Interventional radiology of the gastrointestinal tract

Gordon K McLean received his medical degree from Dartmouth Medical School. Following 1 year’s training in Internal Medicine, he began a residency in Diagnostic Radiology under Dr. Stanley Baum at the University of Pennsylvania. At the completion of the residency and a l-year stint as Chief Resident, Dr. McLean entered into specialized training in Vascular and Interventional Radiology under the tutelage of Dr. Ernest J. Ring. At the completion of his fellowship, he was asked to join the stagof the University of Pennsylvania. Dr. McLean remained at the University for 10 years, eventually reaching the rank of Full Professor and becoming the Director of Angiography and Interventional Radiology. In 1989, Dr. McLean left the University and joined the staff at The Western Pennsylvania Hospital. Here, he continues to devote all of his professional time to the practice of interventional radiology. 90

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INTERVENTIONAL RADIOLOGY OF THE GASTROINTESTINAL TRACT

The relatively short history of interventional radiology has been a turbulent and fascinating one. Initially a small and largely unnoticed outgrowth of diagnostic vascular radiology, it has steadily and increasingly grown, spilling over the boundaries of organ systems and medical disciplines. In the 196Os, a handful of angiographers explored the clinical possibilities of opening and closing blood vessels using relatively atraumatic catheter techniques. At the beginning of the 199Os, the full-time interventional radiologist is becoming commonplace not only in the university setting but in the community hospital as well. Currently, there are more than 100 interventional radiology training programs in the United States and Canada. Subspecialty medical journals have appeared. Lectures, practical tutorials, and categorical courses are regularly listed in national medical publications. A vigorous subspecialty society, the Society of Cardiovascular and Interventional Radiology, also has emerged, attracting a membership of more than 1,000 practicing physicians and scientists. Understandably, radiologists have not been the only physicians to explore and apply the principles of interventional medicine. For example, in addition to interventional radiologists, we now have interventional cardiologists and endourologists, physicians specializing in the use of minimally invasive technologies in their particular areas of interest. The gastrointestinal (GI) tract has not been left out of this revolution, and indeed the development and application of the techniques of fiberoptic endoscopy have revolutionized the diagnosis and treatment of many GI diseases. Impressive as they may be, however, endoscopes and enCUW Probl

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doscopists cannot provide solutions to all of the problems that may plague the digestive tract. By using specialized instruments and techniques guided by highly sophisticated imaging equipment, interventional radiologists can often bring effective and unique solutions to these problems. A discussion of some of these instruments and techniques forms the subject of this monograph.

GASTROINTESTINAL

INTUBATION

Gastrointestinal intubation has long been a routine procedure in the management of many disease processes. Tubes are often placed for decompression of the stomach and small bowel or for the infusion of elemental diets for enteric alimentation. Most tube placement is passive, relying on gravity and peristalsis to carry tubes through the stomach and the pylorus and into the duodenum and small bowel. Occasionally, radiologists are called on to actively assist bowel intubation by manipulating both the patient and the tube under fluoroscopic control. Unfortunately, many of those patients whose need for intestinal intubation is most critical have decreased or absent peristalsis, and traditional tube placement techniques may be frustrating and unsuccessful. Since the 196Os, a variety of methods has been described for intubating the aperistaltic patient.‘-13 Because of the need for specialized equipment and skills, these methods often did not find wide application; however, the expansion of interventional radiology has largely changed this picture. Currently, any center with an established or developing capability in interventional radiology already has both the equip91

ment bate,

and the technical expertise needed to inturapidly and safely, almost any portion of the

bowel. GASTRIC INTUBATION Simple Intubation If a standard nasogastric tube is already in the stomach, it is often possible to direct a J-tipped guidewire out of one of its distal side holes. If a nasogastric tube is not in place, a small one (e.g., no. B-10 French pediatric nasogastric tube) with an added end hole or a specially cut large side hole should be passed. If the intubation is intended to be only temporary, the tube may be introduced through the mouth rather than the nose, avoiding injury to the nasopharynx. Once the tube is in the stomach, a standard guidewire is advanced through the end hole or out of the precut side hole, and the tube is then exchanged for a selective catheter or larger decompression tube. Dificult Intubation If a particularly difficult intubation is anticipated, the patient should be premeditated with a mild sedative (e.g., 1 mg of midazolam hydrochloride by slow intravenous [IV] push), and the oropharynx and proximal esophagus should be anesthetized with a topical spray (e.g., benzocaine [Cetacaine; Cetylite Industries, Inc, Pennsauken, New Jersey1 spray). A no. 8 to 10 French pediatric nasogastric tube is coated with water-soluble lubricant and passed through the patient’s nose or mouth into the esophagus and advanced until minimal resistance is felt. A small amount of contrast material may then be injected through the catheter to outline the obstruction. If the obstruction is quite high and the risk of aspiration great, oily contrast material or a dilute barium mixture should be used. If possible, 2 to 3 mL of water-soluble contrast medium is preferable because of its ability to impart greater anatomic definition and facilitate subsequent guidewire passage. Particular care should be taken with friable lesions to prevent submucosal injection of the contrast material. The initial tube is then exchanged for a selective catheter over a floppy-tipped guidewire. Depending on the topography of the obstruction, the catheter should either be straight or have a gentle distal curve. If the distal esophageal lumen is obvious, a standard guidewire (i.e., either straight or one with a %-mm J curve) can be used to gently probe and pass the obstruction. More often, a torquecontrolled guidewire (e.g., Lunderquist-Ring torque guide [Cook, inc., Bloomington, Indiana]) should be used to allow more controlled exploration of the obstruction. Usually the tip of these malleable guides should be bent at a 30- to &-de92

gree angle approximately 1.5 cm from the wire’s tip. Under continuous fluoroscopic observation, the external portion of the guidewire is then rotated while only the gentlest forward pressure is applied.” It is the gentle searching motion of the moving guidewire that allows a safe and controllable cannulation of the tract; the guidewire should never be forced into a tract in an attempt to buckle through an obstruction. If the lesion is particularly friable, one of the newer “atraumatic” vascular guidewires (e.g., Wholey Hi-Torque standard [ACS, Mountain View, California]) should be used. Once the guidewire appears to be through the obstruction, the catheter is gently advanced over it, and contrast is injected to confirm intraluminal placement. The torque guide is then removed, and a standard floppy-tipped guidewire is advanced well into the stomach.

CROSSING THE PYLORUS In many patients, a long curved (e.g., cobra type) catheter can be used to cross the pylorusx 9 The catheter is advanced along the greater curvature until its tip lies in the distal antrum and is directed up toward the pylorus. Injecting 100 to 500 cc of air through the catheter will distend the gastric antrum, facilitating catheter passage and often filling the duodenal bulb, making fluoroscopic identification easier (Fig 1). Small amounts of water-soluble contrast may also be injected periodi-

FIG 1. A cobra-type catheter has been advanced along the greater curvature into the antrum. Air injected through the tube has filled the stomach and duodenum (d), which can now be easily identified. (From McLean GK, Ring EJ, Freiman DB: Cardiovasc lntervent Rad,ol 1982; 5108-116. Used by permission.) Curr

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tally to check the position of the catheter tip and define the topography of the gastric antrum. If the gastric antrum is scarred and distorted 01 if the stomach is markedly dilated, small-caliber angiographic-type catheters may be ineffective. More often, a small bowel intubation tube, such as the Herlinger enteroclysis tube (Cook, Inc.1 may be used effectively. This large-bore tube is controlled by a heavy torque cable attached to a knurled external knob. By rotating the torque cable and providing a fulcrum effect by palpation of the stomach with a leaded glove, one can rapidly advance the tube directly up to and through the pylorus. If the pylorus is patulous, it can be easily crossed with any guidewire-catheter combination. If there is postpeptic scarring or pyloric spasm, standard flexible-tipped guidewires are usually ineffective (Fig 2). In such cases, torque-controlled guidewires should be used to negotiate the pyloric channel in a controlled fashion. Once the tip of the catheter appears to be in the proximal duodenum, contrast material should be injected to confirm proper positioning. Often, the angle between the first and second portions of the duodenum is acute, and it may be difficult to advance a stiff torque guide, such as the Lunderquist-Ring torque

wire, further into .I ,lodenum. In such a case, the malleable tit, of .-e Guide should be formed d reintroduced (Fig 3). If a into a wide C curve soft-tipped torqueal, guide (e.g., Wholey HiTorque standard) wa: .csed to cross the pylorus, it can generally be redirected deeper into the duodenum without the net 1 for re: haping. CROSSING

STENOTIC

GASTROENTEROSTOMZES

Most gastroenterostomies can be cannulated with a straight or gently curved angiographic catheter. Examination of previous barium studies is extremely important since individual surgical preference dictates a wide variety of sites for placement of the anastomosis. If previous barium studies are unavailable or have demonstrated no flow through the anastomosis, examination of the surgical report should give a clue as to the location to be searched. If the anastomosis is moderately patent, simple torquing of the catheter and probing with a straight or J-shaped guidewire should permit fairly rapid and selective entry into either the afferent or efferent limb of the bowel (Fig 4).14 If the

FIG 2. In this projectron, the pylorus (oj is well seen. The chances of a floppy-tipped guidewire buckling through the pyloric channel and into the duodenal cap (0) are small. This guidewire should be exchanged for one with torque control, or, alternatively, a more rigid intubation tube should be used. (From McLean GK, Ring EJ, Freiman DB: Card~asc Intervent &d/o/ 1982; 5: 10% 116. Used by permission ) Cum

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FIG 3. The guidewire has passed into the second portion of the duodenum, and the catheter is berng advanced over it. Note the C curve on the wire’s tip that allows it to buckle through the duodenal Iumen. (From McLean GK, Ring EJ, Freiman DB: Cardiovasc Intervent Radml 1982; 5:108116. Used by permission.) 93

tion or those in whom multiple attempts to visualize a dysfunctional gastroenterostomy have proved unsuccessful. Although the endoscope cannot provide the complete overall mapping of stricture topology possible with fluoroscopy, it may be invaluable in locating the proximal portion of the stricture and providing the requisite stiffness needed to engage it with a guidewire.15 Endoscopic attempts to cross difficult strictures should usually be performed under fluoroscopy not only to facilitate intubation but also to assure that an appropriate length of guidewire is passed beyond the stricture (Fig 5). A common failing of endoscopists is to pass an inadequate length of guidewire through the constricted area, causing subsequent attempts to dilate the stricture or pass large-bore tubes to suffer from an insufficient length of distal guidewire. Once fluoroscopy has confirmed placement of a sufficient length of guidewire beyond the area, an attempt is made to cross the stricture with a diagnostic or balloon dilatation catheter. If the catheter and guidewire begin to buckle in the proximal bowel as resistance is met in the narrowed area, the endoscope may actually be used to provide a point of support at the site of buckling. The endoscopist directly applies the endoscope to the “back wall” of the catheter-guidewire combination, thus preventing undue buckling in the stomach or gastric remnant. FIG 4. The gastroenterostomy (arrows) has been crossed and a guidewire placed in the efferent loop of bowel. It is often difficult to distinguish the afferent and efferent limbs, and generous amounts of contrast and delayed spot films may be needed to reliably separate the two. (From McLean GK, Ring EJ, Freiman DB: Card/ovast lntervent Radio/ 1982; 5:108116. Used by permission.)

anastomosis is strictured, torque-controlled guidewires should be used in the manner described previously. Because the afferent and efferent limbs may be superimposed on the anteroposterior projection, selective intubation is usually best accomplished with the patient in a steep oblique position. A tilting fluoroscopic table is also very helpful in this setting since it allows the anastomotic site to be identified with only a small volume of contrast medium. If the gastric remnant is particularly dilated or the anastomosis has been placed at a high and somewhat inaccessible position, use of the small bowel tube with its heavy torque cable as described above may speed intubation considerably. : ENDOSCOPICAL.LY

ASSISTED

INTUBATIONS

Occasionally, endoscopic assistance may be invaluable for intubating the bowel, particularly in patients with long-standing gastric outlet obstruc94

FIG 5. An’endoscope has been used to pass a guidewire through the scarred antrum and pylorus in a pediatric patient. In this case, concomitant fluoroscopy has been used to ensure that an adequate length of wire was passed before a balloon dilatation is attempted. The guide’s tip is well into the third portion of the duodenum. Curr

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MANIPULATING GUIDE THROUGH THE BOWEL

WIRES

AND

TUBES

The instruments and techniques best suited for gaining access to the bowel differ from those best suited for manipulating through the bowel itself. Although relatively stiff torque-controlled guides may be ideally suited to cannulating the pylorus or a stenotic anastomosis, once it is inside the bowel, the tip of such a guidewire will repeatedly catch the valvulae conniventes, making passage difficult or impossible. Passage through the lumen of mobile and distensible loops of bowel is best achieved by using guides with extremely flexible tips that will easily buckle around obstructions (e.g., Coons interventional wire [Cook, Inc.]). Similarly, preformed torque-control catheters such as the cobra catheters are usually not well suited for passage through the bowel. A long straight catheter or one with a very gentle distal curve will advance more easily. The distensibility of the bowel together with its peristalsis make passage of catheters and guidewires through it quite different in feel from the passage of catheters and guidewires through the vascular or biliary tree. Often, when catheters and guidewires are advanced externally, there is no immediate corresponding movement at the tip. Instead, the forward pressure is transmitted slowly through the system so that the guidewire moves ahead in a “plastic” fashion after an interval of 10 to 30 seconds.’ If access to the bowel has been gained through the stomach, there is a tendency for catheters and guidewires to coil up into the fundus during manipulation. Frequent fluoroscopic checks should be made to ensure that the path of the guidewire and catheter through the stomach is as straight as possible. If a large loop is formed in the stomach, pulling the catheter and guidewire back somewhat may actually help advance the tip further into the distal bowel. If unusually tight bends in the bowel are encountered (e.g., at the ligament of Treitzl, it may be necessary to reintroduce torque-control guidewires and catheters to negotiate such difficult curves. If a tube is being introduced for simple bowel decompression or enteric alimentation, the tube should be advanced at least to the level of the ligament of Treitz (Fig 6). Preferably, the distal portion of the tube should lie beyond the ligament in the proximal jejunum; more proximal placement risks gastric reflux of the infused so1ution.16 Therefore, when the guidewire over which the final tube will be advanced is placed, it should be positioned well into the proximal jejunum. Often, tension must be applied to the guide to get the tube to advance through a tight pyloric sphincter or around difficult bends in the bowel. Application of this tension causes some length of wire to be pulled Curr

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FIG 6. A nasogastric tube shown advanced to the proper depth in the bowel. The tube’s tip (arrow) should be just past the duodenojejunal junction or ligament of Treitz (T). This position assures maximum use of the small bowel’s absorptive surface while minimizing reflux into the stomach. (From McLean GK, Ring EJ, Freiman DB: Cardiovasc Intervent Radio/ 1982; 5:1088116. Used by permission.)

back, and if the wire is not well beyond the ligament of Treitz, its stiff portion may be insufficient to carry the tube into the proximal jejunum. The techniques for manipulating through the bowel are consistent no matter which portal of entry is selected. In most instances, entry would be through the esophagus; however, successful bowel intubation can be accomplished through the rectum, surgically constructed stomas, or spontaneous enterocutaneous fistulas (Fig 7). TRANSGASTROSTOMY Early

Postoperative

INTUBATION Placement

If a feeding gastrostomy tube has been inserted recently, its external track will be immature, and the tube cannot be safely removed. This situation may be remedied by placement of one or more anchoring devices such as the Cope viscerostomy anchor (Cook, Inc.l.‘7 If such anchors are not readily available or are believed to be contraindicated, all manipulations must be carried out with the gas95

FIG 7. Oblique view of an intubation of the colon. Involvement of the dist al colon by lymphoma has caused a partial obstruction. Using the techniques described in the text, the operator has passed a guidewire through the rectum and sigmoid colon, and it is almost in position to guide passage of a small-bore decompression tube. (From McLean GK, Ring EJ, Freiman DB: Cardiovasc Intervent Radio/ 1982; 5:108116. Used by permission.)

trostomy tube in place. Careful inspection of the lumen of the indwelling gastrostomy tube should first be carried out to ensure that it will admit a small bowel feeding tube. If the lumen is inadequate, attempts at small bowel intubation should be abandoned, or a small-caliber angiographic catheter should be substituted for the small bowel tube. It is important to be aware that if the latter course is chosen, the tube should remain in place for only a short time since such catheters are unsuitable for long-term bowel intubation (see later discussion).

Most feeding gastrostomy tubes that have been placed surgically or endoscopically are positioned so that the tip of the indwelling tube is directed up toward the gastric fundus. Although it may be possible to manipulate catheters and guidewires out an end hole or side vent of the tube, it is usually extremely difficult to guide these catheters into the gastric antrum. One may attempt to alter an unfavorable angle of approach to the pylorus by first manipulating a guidewire out of one of the gastrostomy side vents and passing no. 8 and I2 French Teflon biliary dilators coaxially over the

FIG 8. A, a typical Stamm-type gastrostomy wtth the Malecot tip directed up toward the gastric fundus. Here, a gurdewrre advanced into the tube passes out a side vent and buckles up against the fundus (open arrow). B, by passrng Teflon dilators through the tube and rotating them cephalad (curved arrow), one can sometimes Improve the awkward angle. The gurdewrre now has a more direct approach to the pyloric regron. For clarity, the outer gastrostomy tube IS not shown here. (From McLean GK, Rombeau JL. Caldwell MD, et al: AJR 1982, 139:11291133 Used by permrsslon.) 96

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guide into the gastrostomy tube. While external traction is applied to the tube, the relatively rigid Teflon catheters can be rotated cephalad in a coronal plane, changing the vector of the gastrostomy. A guidewire passed through the central dilator is then directed into the gastric antrum and toward the pylorus (Fig 8).18

Late Postoperative Placement Most gastrostomy tubes that have been in place for 4 to 6 weeks can be removed safely by cutting any anchoring sutures and pulling the tube directly out. Since tube removal may be painful, mild sedation (e.g., 1-2 mg of midazolam by slow IV

push) is advised. If the gastrostomy tract is large (i.e., no. 16 French or greater), torque-controlled catheters and guidewires can be readily manipulated through it to cannulate the pylorus.18 A torque-controlled catheter or a combination of torquable guidewire and catheter is advanced through the gastric lumen and into the duodenum (Fig 9,AJ. Once the proper depth of bowel has been reached, an exchange guidewire is placed (Fig 9,B). The original gastrostomy tube may then be replaced after threading the jejunal feeding tube through its lumen, or an endotracheal tube (which is thinner walled) may be used.lsPzl To preserve the self-sealing external end of most feeding tubes, one must back-load them into the gastrostomy

FIG 9. A, the surgically

placed gastrostomy tube has been completely removed from this patlent with recurrent asptration of gastric contents. A torque guide has been passed across the antrum, and its tip now lies at the junction of the second and third portions of the duodenum. 8, a long, floppy-tipped guidewire suitable for catheter exchanging has been passed well into the small bowel. Despite such an apparently straightforward approach, tube placement may not be simple, and sufficient wire should be advanced to allow back-tension to be applied as the tube is advanced. C, contrast fills the tetunum (J), showtng that the feeding tube IS in good position. The contrast-filled lumen of the smaller tube is seen passing through the larger gastrostomy (arrows). Back-loadrng this small bowel tube has allowed its self-seallng outer valve to be retained. (A and C from McLean GK, Rombeau JL, Caldwell MD, et al: AJR 1982; 139:1129-l 133. Used by permlssron.) Curr

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tube prior to threading the tip over the guidewire and into the small bowel (Fig 9,C). Placement

After

Gastric

Resection

In patients who have a Bilroth II gastroenterostomy, the anastomosis usually lies directly beneath the entry site of the gastrostomy tube (Fig 10,A). A preformed catheter of the Simmons type is advanced through the gastrostomy tube and reformed in the gastric remnant. A guidewire passed through this catheter will be directed almost 180 degrees from the angle of entry of the gastrostomy and can be used to probe the gastric p0uch.l’ Occasionally, endoscopic and fluoroscopic manipulation must be combined to cross a particularly tight anastomosis. Once the anastomosis has been traversed and the efferent loop entered, the more distal small bowel is intubated in the usual fashion (Fig 10,B).

OTHER

SITES

OF INTUBATZON

Any portal of entry into the GI tract may be used in a manner analogous to those described earlier. Tubes may be directly placed through cutaneous

FIG 10. A, contrast

stomas to allow local decompression or infusion of nutrient solutions. If the stoma is patulous, direct access with a straight catheter and a flexible-tip guidewire is usually most efficacious. Stenotic stomas require the use of a torque guide in combination with a catheter as previously described for esophageal stenoses. Indwelling surgical tubes may be removed and replaced with tubes more suitable for enteric alimentation.” The techniques of replacement are straightfotward and involve only a simple exchange over a guidewire of the indwelling surgical drain and subsequent redirection into the more distal portion of the bowel as necessary. Even the transhepatic route has been used in unusual instances.23 Although the more unusual routes are not well suited to chronic intubation, they may provide a ready and effective alternative to IV hyperalimentation over the short term. Rectal intubation for dilatation of strictures of the colon and rectum or for decompression is usually accomplished simply. All rectal intubations, especially those preceding a dilatation, should be performed under antibiotic coverage. This requirement should not be overlooked even if there has been a proximal diverting colostomy.

’

injected through an indwelling gastrostomy tube fills the gastric remnant. Even with such a small residual pouch, the lack of filling of the anastomosed small bowel will make this intubation difficult. Review of the operative note is often extremely helpful in such cases. B, a small Simmons-type catheter has been used to locate and enter the efferent loop. The exchange guidewire has been passed well out into the small bowel, and the guiding catheter is being removed before the feeding tube is placed, (From McLean GK, Rombeau JL, Caldwell MD, et al: AN 1982; 139:1129-l 133. Used by permission,) 98

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The patient is placed on a fluoroscopic table in the left lateral decubitus position. A soft catheter or red rubber tube is coated with lubricant and introduced into the rectum, and air is injected to define the anatomy. Because of the tendency for contrast material to pool in the rectum, it should be used sparingly. The techniques employed are identical to those described earlier for other portions of the GI tract (see Fig 7). Occasionally, strictures located deep within the distal bowel require an endoscopic approach. In such cases, the colonoscope is advanced up to the stricture, and a guidewire is advanced across under fluoroscopic guidance. Once the guidewire is well into the proximal bowel lumen, the colonoscope may be removed and the intubation and/or dilatation is completed under fluoroscopic guidance. TUBE

SELECTION

AND

PLACEMENT

Because of their stiffness and relatively low coefficients of friction, polyvinyl and polyethylene tubes are the easiest to position in the bowel. Although suitable only for short-term placement, they can serve a variety of therapeutic and diagnostic needs. The guidewire over which the tube will be introduced should be long enough to accommodate the entire tube externally; a ZlO- to 260-cm heavy duty exchange guide is usually adequate. If the tube has no end hole, one should be cut with a large hole punch. The tube is coated with water-soluble surgical lubricant and threaded over the guidewire. If an esophageal lesion prevents easy passage, the esophageal lumen can be enlarged by means of balloon dilatation (see later discussion). If resistance at the pylorus or gastroenterostomy is present, there is a tendency for both tube and wire to buckle in the stomach; however, if a sufficient length of guidewire has been advanced beyond the ligament of Treitz or into the small bowel, there should be little difficulty in applying sufficient tension to the wire to allow the tube to pass. In the rare instances in which no standard tube can be advanced across the pylorus or other obstruction, a toposcopic or everting catheter may be effective.24 First developed for catheterization of tortuous blood vessels, this design has been adapted to the GI system, and catheters are available for both interventional radiologic and endoscopic use. Unfortunately, the tubes that are easiest to pass through the bowel are those least well suited for long-term use. Standard polyethylene or polyvinyl nasogastric 10 to 12 French tubes can usually be passed with little difficulty. Even standard angiographic catheters have also been used for enteric alimentation, their small size and torque control allowing them to be manipulated beyond highCurr

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The difficulty with all of grade obstructions.ZS these tubes is that over a relatively short period of time they become extremely rigid and begin to erode the bowel wall.““, 27 A variety of tubes has been designed for longterm placement in the bowel. Unfortunately, many of these tubes suffer from an inherent deficiency in that they were designed for passive placement and not for active guidewire-directed placement. Tubes such as the Dobhoff (Biosearch, Somerville, New Jersey) may be placed over a guidewire by passing the end of the guidewire into the most distal side hole and bringing it out the hub. The weighted tip of the tube folds back as it is advanced over the guidewire into the bowel.” This approach is clumsy and risks failure if the weighted tip of the tube remains folded (i.e., kinked) once it is placed deep in the bowel (Fig 11). The recent development of enteric tubes (e.g., McLean-Ring enteric feeding tube [Cook, Inc.11 specifically designed for placement over the guidewire considerably simplifies intubations for enteric alimentation.28 The distal ends of such tubes are weighted, and the tips are pierced through with an end hole, allowing the entire tube to be advanced directly over a standard guidewire. Once the guidewire is in position, these tubes are passed coaxially over the guide into the bowel (Fig 12). Replacement of such tubes is also simple, since the guidewire may be advanced directly through the end hole, allowing for a direct and simple exchange. COMPLKXTIONS

Enthusiasm for tube placement should be tempered by the knowledge that iatrogenic intubation injuries are relatively common.27’ “, 3o The most common problems are those of simple occlusion from inspissation of injected materials or kinking of the soft tube material (Fig 13). The frequently reported complications resulting from passage of feeding tubes into the tracheobronchial tree should be avoided if fluoroscopic guidance is used during placement.“1-33 Necropsy studies have shown that 60% of patients sustain injury to the esophagus or hypopharynx following gastric intubation, but only 2% of these intubation injuries will be clinically apparent.34 Ulceration and mucosal bruising are the most common injuries, but actual perforation of the hypopharynx, esophagus, or stomach may occur. The risk of intubation injury is greatest in the pediatric age group.35 When tubes remain in the bowel for long periods of time, their physical characteristics change. Polyvinyl and polyethylene tubes begin to discolor and harden after as little as 6 to I2 hours in the small 99

FIG 11. A, placement of a Dobhoff tube usrng a guidewire. The guide has been advanced well into the bowel beyond the duodenojefunal junction (arrow). The tube is being advanced over the guidewire. Only the metal-weighted tip is visrble as it folds back while passing through the pylorus (P). 6, the tube is now in place, with I& trp past the ligament of Treitz (T). Contrast fills the bowel, but the weighted-tip remarns folded back, kinking off the distal end of the tube. (From McLean GK, Ring EJ, Freiman DB: Caru’iovasc lntervent RacOol 7982; 5108-i 16 Used by permission.)

FIG 13.

FIG 12. A guidewire-directed tube being passed into the proximal small bowel. By sliding coaxially over the heavy guide, the tube can be rapidly and accurately placed almost anywhere in the bowel.

100

A transgastrostomy feeding tube that no longer functions properly. Most such problems result from inadequate flushing with water or saline so that feeding solutions are not effectrvely cleared from the lumen. Here, a combination of kinking and knotting of the tube in the stomach has produced a partial occlusion. (From McLean GK, Rombeau JL, Caldwell MD, et al: AJR 1982; 139:1129-1133. Used by permissron.)

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bowel .26,27 If these tubes are not exchanged on a regular basis, erosion and ulceration of the mucosa may eventually lead to perforation. For the most part, silicone rubber (Silastic) and other biologically compatible tubes can remain safely in the lumen of the bowel for long periods of time and are well tolerated by most patients. However, even the softest and most biocompatible tubes can erode into the bowel wa11.3”

GASTROINTESTINAL

DILATATION

Traditionally, patients with enteric strictures have been treated by bougienage or surgery. Bougienage of esophageal strictures is a relatively benign procedure, and in experienced hands, success rates of 80% or greater have been reported.“” However, when strictures are long or irregular or are associated with esophageal ulceration or malignancy, the blind passage of a bougie may be hazardous. The advent of esophageal replacement procedures such as gastroplasty or colonic interposition has further limited the utility and safety of blind bougienage by giving rise to a whole new type of stricture resulting from enteric anastomoses and associated with a complex restruc-

FIG 14. A, 2 months

after a gastric liquids. A small-bore tube tube’s tip is indenting the conventional bougienage. the anastomotic stricture.

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tured anatomy (Fig 14). In many cases, fiberoptic endoscopy may extend the effectiveness of conventional forms of bougienage by allowing a more precise visualization of the proximal portion of the stricture; however, endoscopy cannot provide the overview of stricture anatomy afforded by contrast studies done under direct fluoroscopic control (Fig 15). Surgical resection or bypass of strictures is another traditional method of treatment. Operative repair of esophageal strictures may offer long-term success rates as high as 83%,37 but patients are subjected to the morbidity and mortality of operative intervention, which may run as high as 17% and 30%) respectively.38 For those lesions located distal to the esophagus, surgery has traditionally been the only form of therapy. However, the operative mortality in elderly patients and particularly in those with malignancies may be so high as to preclude this means of therapy in symptomatic patients. In response to the risks and limitations of surgery and bougienage, techniques have been developed to permit rapid, atraumatic placement of balloon dilating catheters into enteric strictures.3” Although initial placement of balloon catheters results in some shear stress to the strictured area,

pull-through procedure for obstructing esophageal carcinoma, this man is still unable to swallow solids or passed into the esophagus demonstrates severe narrowing at and above the anastomotic site. Note that the inferior mucosal surface (arrow). This is the type of postsurgical anatomy that is at high risk for perforation with B, using fluoroscopic guidance and atraumatic torque-controlled guidewires, the operator has safely crossed Here, a dilating balloon has been positioned for treatment of the stricture.

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TECHNIQUE

FIG 15. In this young woman, a flexible, pediatric direct the passage of a bougie through ture. Despite all precautions, the bougie and this mediastinal abscess resulted.

endoscope was used to a high esophageal stricperforated the esophagus

this stress is minimal, much less than that resulting from the passage of bougies. Once they are properly positioned, dilating balloons apply a purely radial force to the stricture. Balloons specifically designed for dilatation of enteric strictures are available in diameters of 10, 1.2, 1.5, and 20 mm. Although composed of plastics with a high tensile strength, inflation pressures of these balloons are limited to a range of 4 to 6 atm because of their large diameter (LaPlace’s law). Fortunately, these relatively low inflation pressures appear to be adequate for the treatment of the majority of enteric strictures. Enteric balloons have a working length of 8 cm, simplifying the dilatation of esophageal strictures, which are frequently long. Smaller diameter vascular balloons are occasionally useful for the initial dilatation of extremely tight strictures (Fig 161. These balloons may be used in tandem to obtain a larger effective working diameter, but attempting to obtain a “definitive” diameter with them is awkward and less effective than using enteric balloons.

102

FOR

ESOPHAGEAL

DILATATION

If available, previous esophagograms should be reviewed to gain familiarity with the relevant anatomy. Unless the dilatation precedes placement of a permanent drainage or feeding tube, the oropharynx is the preferred route of approach since passage of large dilating balloon catheters through the nasopharynx may be difficult and traumatic. The hypopharynx is initially anesthetized with a topical anesthetic spray (benzocaine). If patients are particularly apprehensive or if previous experience has shown that the dilatation is likely to be painful, an IV anxiolytic agent (e.g., 1 mg of midazolam) is used. An exchange guidewire of 210 to 260 cm is then passed through the catheter and is used for placement of the dilating balloon catheter. Selection of the appropriate size of dilating balloon depends on the diameter of the stricture and the surrounding esophagus. If the stricture is particularly tight (i.e., a lumen of 2 mm or less), initial dilatation may be best accomplished with a 6- to 8-mm vascular dilating balloon. If the lumen is larger, the initial balloon used may be an esophageal dilating balloon with a lo- to 12-mm inflated diameter. If the initial dilatation is easy and the procedure is well tolerated by the patient, balloons of increasing size are substituted up to a diameter of 20 mm or more (Fig 17). If at any time the patient suffers severe pain, or if a persistent waist remains in the balloon despite maximum inflation pressures (i.e., approximately 6 atm), the dilatation is discontinued. Balloons are inflated three times, each inflation lasting 30 to 60 seconds. Immediately following the dilatation, an esophagogram is obtained using dilute barium or watersoluble contrast material. The apparent esophageal diameter and appearance should not be used to predict the patient’s response (i.e., symptomatic outcome) (Fig 18). Estimates of outcome based on the apparent luminal diameter seen on postdilatation studies have been shown to have no correlation with short- or long-term symptomatic response.40, 41 Spot films are taken solely to document the presence or absence of any mucosal esophageal tears so that appropriate instructions about diet can be given (Fig 19). In the absence of radiographically obvious mucosal injury, patients are instructed to begin intake of clear liquids 4 hours after discharge and to begin advancing their diet as tolerated beginning the following morning. If small mucosal tears are seen, patients should take nothing orally until the following morning and are instructed to limit their intake to clear liquids for the following 24 hours, and then advance their diet as tolerated. Injuries more extensive than small mucosal tears mandate hospital admisCurr

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1990

FIG 16. A, a high-grade caustic stricture that produced balloon. B, 24 hours after the initial dilatation,

complete a 15mm

dysphagia. Here, the lnltial dllatatlon is being entenc balloon is used to achieve a functional

sion and close monitoring for at least 24 hours following dilatation. Most patients can be discharged immediately after the procedure. Those patients receiving IV medications are monitored for 1 to 2 hours and then discharged. For most patients, the frequency of dilatation following the initial treatment is dictated purely by symptomatic response. Inpatients with severe strictures are dilated on alternate days while in the hospital. Outpatients with severe strictures are generally dilated once each week until the symptoms abate sufficiently for them to be able to monitor their own need for redilatation. When patients are able to monitor their own symptoms adequately, they are instructed to contact the interventional radiology section to schedule an appointment for repeat outpatient dilatation. Curr

Probl

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1990

performed esophageal

with an &mm lumen.

vascular

Occasionally, intubation and dilatation of the esophagus may be requested in patients with a feeding gastrostomy and an obstructing esophageal carcinoma prior to the operative placement of a Celestin tube or other esophageal endoprosthesis. The techniques for the procedure are essentially those described earlier and merely require a different access route. The gastrostomy tube is first removed, and a catheter and torque control guidewire are passed through the stomach and up into the esophagus. Particular care should be exercised when one is dealing with large obstructing carcinomas since necrosis is common and perforation through the esophageal wall is a risk. Once the guidewire and catheter are passed through the esophagus, a balloon is used to dilate the esophagus to a diameter suitable for place103

FIG 17. A, gradual

dilatation of a trght anastomotic stricture. The cular balloon, Here two distinct waists can be seen (same A lumen of 8-mm has been achieved as the initial step. esophageal balloon. Note that this balloon has a diameter a functional 15.mm lumen was achieved in this patient.

initial balloon selected for dilatation of this anastomotic lesion is an 8-mm vaspatient as in Fig 14). B, after three inflations, the balloon has a smooth contour C, 10 days after the first treatment, the lesion is being dilated with a 15mm of approximately IO-mm at the waist, a considerable improvement. Eventually,

FIG 18. A, prior to dilatation, there ing achalasia. B, a 20-mm

is little appreciable lumen in the region of the lower esophageal sphincter of this elderly man wtth long-standesophageal balloon has been inflated across the narrowed region of the lower esophageal sphincter. Some authors have advocated using multiple large balloons to treat patients with achalasia. w C, the postdilatation contrast study is not very impressive. Although the lumen is nominally increased compared with Ai the result appears to be minimal. Despite this, the patient reported full symptomatic relief for the next 4 months, a “good” result with this chronic condition.

104

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FIG 19. Postdilatation esophagram. Only mlnimal mucosal irregularity is seen following balloon dilatation of this midesophageal stricture. This patient will be able to begin oral Intake in 4 hours.

ment of the endoprosthesis. Following the dilatation, the balloon catheter is removed over an exchange guidewire, which can then be used to guide passage of a large nasogastric tube. If the nasogastric tube is left in place through the dilated area, it can serve as a guide for placement of the endoprosthesis. The presence of the tube decreases the chances of esophageal tearing or disruption during the surgical procedure.

TECHNIQUES OF GASTROENTEROSTOMY PYLORIC DILATATION

AND

In patients with stenotic gastroenterostomies or strictures of the pylorus, the oropharynx is anesthetized as previously described. A nasogastric tube is initially passed into the stomach, and thin barium or water-soluble contrast medium is injected through the tube to define the stricture fluoroscopically. Depending on the anatomy, a straight or curved catheter or a small bowel intubation tube used in combination with torque control guidewires is advanced into the stomach or gastric remnant to traverse the stenosis. In some patients with stenotic gastroenterostoCurr

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1990

mies, the obstruction will be so complete as to block any passage of contrast material through the anastomosis. If this is the case, examination of previous upper GI studies may be helpful in determining the exact location of the surgical anastomosis. In the absence of such information, examination of the surgical report may be invaluable since the site of anastomosis may vary considerably according to the individual surgeon’s preference. Once a guidewire and catheter have been passed through the anastomosis, the catheter should be injected with contrast medium to define the anatomy (Fig 20,A and B). If a single Roux-en-Y loop has been used, a balloon catheter is substituted, and the dilatation is performed as described earlier. Generally, balloons with a 12- to 15-mm inflated diameter are suitable for gastroenterostomies. If the stricture is in a patient who has been operated on for morbid obesity, careful consultation with the operating surgeon prior to dilatation is essential, since the exact size of the anastomosis may be critical in determining the long-term effectiveness of the surgery. The length of esophageal dilating balloons (i.e., 8 cm) may prove to be somewhat awkward when one is dilating strictured gastroenterostomies; however, the precise sizing available by using these balloons generally overrides any disadvantages (Fig 20,C and D). Long balloons have a tendency to fold or kink when crossing bends in small bowel loops. These folds or kinks should not be mistaken for the actual stricturing lesion. Shorter balloons (i.e., 3-6 cm) with inflated diameters of 15, 18, and 20 mm are made for cardiac valvuloplasty and, if readily available, may prove useful in selected cases in which the use of long balloons is particularly awkward. In patients with long-standing pyloric obstruction, the stomach may be markedly distended, and the catheters used for most routine stricture intubations may prove ineffective (Fig 21). In such cases, the Herlinger tube used for diagnostic intubation of the small bowel may prove extremely effective. This tube is directed by means of a large torque control cable combined with external palpation with a leaded glove. With some practice, this technique will allow a rapid intubation of the pylorus in the majority of patients. In rare instances, the stomach will be so dilated and the pylorus or gastroenterostomy so stenotic that conventional means of fluoroscopically guided intubation will fail. In such cases, strictures may be bypassed by combining the advantages of fluoroscopy with those of endoscopy. An endoscope can be advanced up to the proximal aspect of the stricture and the guidewire passed into it under direct visualization. It is essential that the endoscopy be performed where fluoroscopy is 105

FIG 20. A, contrast

fills a small gastric pouch. Although some of the contrast has entered the drainrng bowel loop, the exact pornt of connection is not apparent. B, after the pouch was gently probed wrth a guidewire, the connection was located and crossed. A catheter is being used to fill the jejunum with contrast. C, a 12-mm drlatrng balloon has been selected to approximate the size of the original surgical anastomosis. D, following the dilatation, there IS good emptyrng of the gastric pouch. Contrast now flows into the efferent jefunal limb.

106

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FIG 21. Gastric distention complicating pyloric intubation. The guidewire has been passed through a stenotic pyloric channel, and its tip is coiled at the ligament of Treitz. Note the long path followed by the guide through this markedly enlarged stomach. This degree of distention will make intubation of the small bowel extremely difficult.

available since endoscopists tend to pass too short a length of guidewire beyond the strictured segment. When later attempts are made to exchange for a balloon catheter, the short length of guidewire pulls back through the stricture, frostrating the procedure. Usually, once fluoroscopy has shown that an adequate length of guidewire has been advanced through the stricture, the endoscope can be withdrawn and a regular catheter inserted as previously described. Occasionally, if the initial catheter or the balloon catheter buckles excessively in the stomach, the endoscope must be reintroduced and used as a fulcrum point against which the catheter can push so as to allow the catheter to advance through the stricture (Fig 22). Generally, balloons with a lo- to 15-mm inflated diameter are used to dilate the pylorus. Since these strictures tend to be associated with longstanding peptic disease, they are generally very difficult to dilate, and the achieved lumen is less than that of the fully inflated balloon catheter. However, balloons of these sizes will produce a lumen adequate for gastric emptying and relief of the symptoms of gastric outlet obstruction in the majority of patients (Fig 23).

TECHNIQUE FOR DILATING ENTERZC STRICTURES

MZSCELLANEOUS

A stricture associated with a cutaneous stoma can be directly intubated by a combination of direct visualization and fluoroscopy. The guidewire, followed by a catheter, is passed an adequate distance into the loop of bowel. After contrast meCurr

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1990

FIG 22. A, combining endoscopy and fluoroscopy to dilate a difficult stricture. The pylorus was successfully crossed with a guidewire but proved to be too tight for passage of the catheter. The balloon shown here was chosen because its small outer diameter (1.e , no 7 French) permitted it to pass through the pylorus. B, the endoscope remains In place while a second, more definitive 12-mm balloon is passed. The support offered by the relatively rigid endoscope greatly facilitates intubation In selected cases.

dium injection confirms intraluminal placement, exchange is made for an appropriate size balloon catheter (Fig 24). Rectal strictures and distal colonic strictures are approached by placing the patient in a lateral decubitus position on a fluoroscopic table. A short catheter with a general purpose curve is introduced into the rectum and is used to direct a torque control guidewire up to and through the stricture. If a single balloon is used to dilate coionic strictures, it should be at least 20 mm in inflated diameter (Fig 251. Often, multiple balloons must be used so that an approximately normal luminal diameter can be achieved. By use of a triple balloon technique, a nearly circular lumen of virtually any desired diameter can be obtained.” Before dilatation of any rectal or colonic stricture is attempted, the patient should be placed on broadspectrum antibiotics; patients with prosthetic heart valves or other conditions that place them at increased risk should receive lV antibiotics. These precautions should be observed even when strictures in a defunctionalized loop of bowel (i.e., a mucous fistula) are dilated. Strictures deep within the bowel may be ex107

FIG 23. A, tble findings outlt

srmp throw call\ con1 tion

108

of long-standing peptic disease are seen in this barium study of a 77-year-old woman with symptoms of subi :otal gas ;tric ?t obstruction. B, a 12-mm balloon has been inflated in the pylorus. It is difficult to distinguish resistant or residual ste ‘noses hvorn )le kinking of the balloon in the bowel. Note that only a short length of wire remains in the duodenum after manipulatrng the ball1 3017 Jgh the stenosis. C, the balloon has been partially deflated and pulled back through the region of the pyloric channel. F:Iuorosc( opir, no deformation of the balloon was seen, so it was reasonable to assume that a 12-mm channel had been achieved. D, injec :ted rast shows some mucosal detarl but is usually not able to predict symptomatic outcome In this case, the symptoms of out let obstr UCwere relieved

Cum Probl

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1990

FIG 24. A, air and contrast injected into the subcutaneous portion of an rleocutaneous stoma demonstrate passed through the stricture and contrast injected to confirm intraluminal placement. C, a heavy-duty ileal loop. D, a IO-mm dilating balloon is inflated in the stricture. Prophylaxis wrth antibiotics should stoma-associated strictures.

tremely difficult to approach without endoscopic guidance. The endoscope can be used to approach a lesion and pass a guidewire through the strictured area. Fluoroscopic guidance is essential to ensure that a length of guidewire adequate for subsequent catheter exchanges is passed. Generally, balloons with a 15- to ZO-mm inflated diameter should be used for enteroenteric anastomotic strictures (Fig 261. COMPLKXTIONS

Because of the advantages of fluoroscopic control and the application of a predominantly radial dilating force to the strictured area, complications are extremely unusual when enteric strictures are dilated by balloon catheter technique. Judicious use of torque guides and frequent injections of contrast should minimize any risk of perforation. A cautious approach is especially important when one is dilating those patients with malignant strictures, since necrotic tumor may replace part of the bowel wall. If the catheter perforates the bowel wall, it is withdrawn while gently injecting contrast material until the true lumen can be identified, and a torque control guide is used to redirect the catheter along the appropriate route. Dilatation is generally undertaken in stages to minimize the risks of esophageal tears or perforation. Through-and-through tears (i.e., perforations) of the esophagus have been reported in patients undergoing balloon dilatation.43m4” Small mucosal tears are occasionally seen after dilatation, but these are generally not symptomatic. Overall, the incidence of esophageal tears, either into or through the mucosa, has been less than 2% .‘O,43P45 This number includes even those patients with ulcers associated with their strictures; there appears Cum

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1990

a structure. B, a curved catheter is guidewire has been coiled In the be undertaken prior to dilatation of

to be no increased incidence of perforation OI tearing of the esophagus in patients with associated ulcerations (Fig 27). Contrast studies performed immediately after dilatation are primarily intended to exclude the possibility of disruption of the bowel. Either a barium mixture or water-soluble contrast medium may be used-the choice depends on the clinical circumstances. These studies are important for medicolegal reasons and to assist in the selection of an appropriate diet following the procedure. In most cases, patients can begin a liquid diet 8 hours after the dilatation. The diet is then advanced as tolerated starting the following day. If any disruption of the mucosa is seen or suspected, this process should be delayed for at least 24 hours following the dilatation. It is interesting that the radiographic appearance seen on studies obtained immediately after a dilatation has essentially no predictive value in regard to eventual symptomatic outcome. By and large, postdilatation radiographs are disappointing, showing a lumen that is much smaller than would have been predicted from the size of the balloon used and that frequently appears entirely inadequate for relief of symptoms. However, several reviews have demonstrated absolutely no correlation between the postdilatation radiographs and symptomatic relief.40’41 Accordingly, these studies should be viewed solely as documentation of mucosal integrity following the procedure. OUTCOME

Overall, most enteric strictures can be successfully intubated and dilated; esophageal dilatations especially have shown high rates of success,40, 43,44,46 47 Strictures occurring in the GI 109

FIG 25. A, a double-contrast

examination demonstrates a carcinoma of the sigmoid colon. B, following surgrcal resection and construction of an end-to-end anastomosrs, the patient experienced recurrent symptoms of colonic obstruction. The postoperative barium study shows a high-grade stricture at the anastomotic line. C, a 20.mm balloon has been centered in the stricture and inflation begun. Note that the patient IS In the lateral decubitus position. D, full inflation has been achieved. Note that the original anastomosis was slightly larger than the balloon drameter (i.e., approximately 24 mm).

tract distal to the esophagus involve more technical difficulties, and consequently, intubation failure rates as high as 30% have been reported in anastosome series.“’ Strictures at gastrojejunal moses appear to be those that present the most technical difficulties (Fig 28). In fact, as a group, anastomotic strictures present more difficulties than those occurring in the native bowel. The majority of enteric strictures respond well to dilatation, with more than 80% showing improvement or relief of symptoms on short-term fol110

low

up.4o.

43,46.47

It is sometimes difficult to determine the exact end point of a series of planned dilatations, especially if the strictures are long standing. An unbiased appraisal should be made of all patients who have finished a planned course of balloon dilatation. Such a review will allow those in whom the procedure has obviously failed to be referred for surgical repair if indicated. Assessing the long-term efficacy of balloon dilatation in relieving symptomatic strictures is somewhat problematic. Overall, more than 80% of those

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1990

FIG 26. A, supine

and, B, decubitus views from a double-contrast barium study suggest narrowing at the site of an ileocolic anastomosrs. C, a compression spot film confirms the presence of anastomotic narrowing. The patient had complained of persrstent abdominal pain followrng resectron of a cecal carcinoma. D, a colonoscope was used to place an extra-long guidewire through the descending colon and the anastomosis. A dilating balloon has been centered in the anastomosis, which can be identified on fluoroscopy by the visible suture line (arrows). E, as Inflation begins, an obvrous waist appears at the narrowed anastomosrs. F, at full inflation, the stricture IS dilated to 20 mm. This single dilatation provided permanent symptomatic relief. (A-C and E and F from McLean GK, Cooper GS, Hartz WH. et al: Radfology 1987; 165:35540. Used by permrssion.)

patients who undergo a successful dilatation procedure will remain symptom free for 1 year after their last balloon dilatation.4’ This number decreases to approximately 70% at 2 years’ follow up. In a large series, when patients with esophageal and nonesophageal strictures were evaluated separately, the former group initially fared worse than the latter.41 Eighty-one percent of patients treated for esophageal lesions were symptom free 6 months after the procedure, the number decreasing to 71% at 9 months. In contrast, no patients successfully treated for a nonesophageal stricture complained of symptom recurrence until more than 21 months after the dilatation. This pattern differs markedly from that seen during short-term follow-up where failures occur predominantly in the nonesophageal group. Interestingly, procedural characteristics aside from primary failure of intubation and dilatation have proved to be of no value in predicting symp-

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1990

tomatic outcome. Generally speaking, patients in whom other modalities (e.g., bougienage) have failed are more likely to have technically difficult or unsuccessful procedures. This situation suggests that prior failure may select a subgroup of strictures that are more difficult to dilate by any modality. However, once successful intubation and dilatation have been achieved, the history is relatively inconsequential, and long-term symptomatic improvement is unaffected (Fig 291. Patients with malignant strictures have a less favorable prognosis than those with benign strictures in terms of both symptom recurrence and the need for alternative procedures. The striking differences seen at follow up are hardly surprising given the usual clinical course of patients with malignant esophageal or gastrojejunal obstruction. Nonetheless, despite the unimpressive long-term efficacy of the procedure in relieving symptoms, a trial of balloon dilatation is justified in many of

111

FIG 27. A, reflux esophagrtis

has because of the chronicity C, Immediately followrng there IS no demonst;able increased until the patient mains on banum studres, the orrgrnal ulcer.

112

produced an extremely high-grade stenosis of the distal esophagus. Note the small associated ulcer (arrow). B, of the disease process and the severe lumrnal narrowing, drlatation was begun with a small (i.e., 6-mm) ballo on the initial dilatation, the strictured area appears indistinct. Although there IS lrttle appreciable mucosal de1 tail, tear of the esophageal wall. Note the tertiary contractions above the stricture. D, balloon size was gradu, ally could tolerate dilatation with a 20.mm balloon.‘E, the final result is excellent. Although minimal narrowing rethe patient reported complete symptomatrc relref. Note that there is no demonstrable abnormality at the site ? of

Cwr

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1990

FIG 28. A, an obstructed

gastrojejunal anastomosis presentrng considerable technical difficulties. The anastomosis lies almost immediately below the tip of a gastrostomy catheter. The anastomosis has been crossed with diagnostic catheters passed from both above and through the gastrostomy tube. A catheter tip (arrow) is seen injecting contrast Into the efferent Iamb. B, a 12-mm esophageal dilating balloon has been passed through the anastomosis. The configuration of the balloon seen here IS strongly suggestive of a plication defect, a fold II- the bowel wall rather than a true, fixed obstructron. C, full inflation across the anastomosis. Despite the encouraging radiographic appearance, the anastomosrs still did not function after this. Reoperation revealed kinking of the efferent limb.

FIG 29. This stricture at a duodenojejunal anastomosis had been classed as “resistant” after multiple failed attempts at endoscopic dilatation. However, once a guidewire had been passed under fluoroscopy, dilatation was relatively uneventful, and the patlent experienced symptomatic relief.

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113

these patients. Balloon dilatation is a quick procedure associated with very low morbidity and mortality. Alternative modes of treatment, such as radiation therapy, surgical resection, or bypass, involve considerably more time and risk. In addition, some patients are not considered appropriate candidates for any of the more conventional forms of palliative therapy. Given any of these conditions, it

seems reasonable to attempt a short-lived palliation by balloon catheter dilatation of malignant strictures. Anastomotic strictures are an interesting subgroup of benign strictures. Anastomotic strictures are usually short lesions stemming from a single, discrete event, and it would thus appear that these lesions are almost ideally suited for balloon cathe-

FIG 30. A, dilatation of an anestomotrc stenosrs The site of an esophagogastric anastomosis is apparent from the suture Irne. A balloon is being centered In the lesson. B, the waist in the balloon shows a typical thrn and weblike appearance. C, once the lesion has been dilated, the fully Inflated balloon moves freely through the prevtously narrowed site without deformation (the balloon has been somewhat depressurrzed prior to the attempt of this maneuver) D, contrast injected through the balloon catheter flows into the stomach. This single dilatation produced symptomatic relief (A, B, and D from McLean GK, Cooper GS, Hartz WH, et al. Rad/o/ogy 1987; 165:35-40. Used by permrssron.) 114

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1990

ter therapy (Fig 30). Although no statistically significant differences have been seen, life table analysis tends to support this hypothesis.41

PERCUTANEOUS

ACCESS

PERCUTANEOUS

PROCEDURES

GASTROSTOMY

A simple tube gastrostomy is a convenient way of providing long-term enteric alimentation as well as gastric decompression. Although the operation is generally not a complex one, complications are frequently high (9%-46%) because of the risks of general anesthesia in a patient population that is frequently quite debilitated.48-50 Both endoscopic and fluoroscopic techniques that allow placement of a feeding gastrostomy without general anesthesia have been described.51-56 Although both approaches are usually effective, a purely percutaneous approach done under fluoroscopic guidance is the only practical one in patients with advanced esophageal disease in whom an endoscopic approach is not possible. Most patients referred for gastrostomy will be unable to take oral nutrition; however, if any oral intake is possible, it should be discontinued and the patient should fast for at least 24 hours before the procedure. Ultrasound examination and, to a lesser extent, computed tomography (CT) are useful prior to the procedure, since both the left lobe

of the liver and the transverse colon may overlie the area to be punctured. When preprocedural imaging is performed, a safe window of access should be clearly marked on the skin. Intravenous glucagon (1 mg) is given to block gastric peristalsis, and if possible, a pediatric nasogastric tube is passed into the stomach. A sufficient amount of air (usually 200-400 cc) should be insufflated so that the gastric air bubble is easily seen on fluoroscopy. Oblique or lateral views should show the gastric air bubble almost in apposition to the anterior abdominal wall. Adequate gastric distention usually displaces the transverse colon inferiorly, safely away from the site of puncture. If the position of the colon is not clear on fluoroscopy, a rectal tube is placed, and air is inflated to define its exact position. If considerable doubt as to the position of the colon remains, or if there is an abnormally large left hepatic lobe, the initial puncture should be performed under ultrasound guidance. Choice of a puncture site depends on the expected long-term use or uses of the gastrostomy. Simple decompression or direct gastric feedings may be easily accomplished with a tube directed through the lateral portion of the rectus sheath in a cephalad direction. This vector will carry the tube tip up into the gastric fundus (Fig 31). However, if transgastric jejunal intubation will be necessary immediately or in the future, a more lateral and horizontal puncture is preferred, since this

FIG 31. A, placing

a simple feeding gastrostomy. The initial puncture has been directed cephalad through the lateral aspect of the rectus sheath. The guidewire is coiling in the fundus. B, because of scarring from a previous gastric procedure, a tapered, Teflon dilator is passed over the guldewtre before the gastrostomy tube IS inserted. C, a no. 12 French loop catheter has been placed. In most situations, a more lateral approach would be preferred since it would allow for later converslon to a gastrolejunostomy. Cum

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115

will allow more direct access to the gastric antrum and pylorus for small bowel intubation. Once the appropriate puncture site has been selected, local anesthesia is obtained with I% lidocaine (Xylocaine), and a puncture is made through the skin and fascia with a no. 11 scalpel blade. A 22-gauge Chiba needle is then passed through the cutaneous entry site and into the stomach with a single thrust. Too oblique a passage through the gastric wall will make subsequent dilatation of the gastrostomy site difficult. In a patient who has not had previous gastric surgery and does not have ascites or an excessively thick abdominal wall, the Chiba needle should pass directly into the stomach with a single thrust. The Cope biliary catheterization system (Cook Inc.) is then used to enlarge the initial gastrostomy entry site and allow placement of a 0.038-in. standard guidewire. In some circumstances, an initial approach with a 22-gauge Chiba needle may be difficult. If the abdominal wall is particularly thick, if the fascia is particularly tough, if ascites is present, or if a previous gastrostomy or gastric surgery has produced scarring in the area to be punctured, passage of a thin needle will be difficult if not impossible. In such cases, a trocar approach can be used. An 18gauge needle fitted with a 5 French Teflon sheath is passed with a single thrust through the abdominal wall into the stomach in as perpendicular a

FIG 32.

plane as possible. VanSonnenberg et al. have suggested that such an approach may be facilitated somewhat by supporting the gastric wall internally with a fluid-filled intragastric balloon.“” A heavy-duty guidewire (e.g., Amplatz exchange guide, Cook Inc.) should then be passed well into the stomach, and the tract should be dilated with tapered coaxial dilators or an appropriately sized high-pressure dilating balloon catheter. Despite the lack of adhesion of the gastric wall to the abdominal wall, tract dilatation generally does not push the stomach away from the abdominal wall. In most cases, dilatation to a functional lumen of no. 12 French or more is possible at the time of the initial gastrostomy placement. Recently, simple anchoring devices ideally suited to securing the stomach to the abdominal wall have been developed.17, 57 These “viscerostomy anchors” are inserted through a needle and are used to provide greater security during the initial dilatation and catheter placement (Fig 32). A simple Cope loop or Malecot catheter is then advanced into the stomach and is brought back against the anterior abdominal wall (Fig 33). The catheter is secured externally, by direct skin suturing, a Molnar disk, or a stoma to which the catheter may be sewn. A no. 10 French catheter is usually adequate for initial gastric decompression and also has a lumen sufficient for the passage of standard enteric feeding solutions (Fig 34). Obviously, the tube functions

:

A, a Cope

viscerostomy anchor is being used to secure the gastric wall before placement of a percutaneous gastrostomy. The 18-gauge thin-walled needle has been passed into the distended stomach. Note the anchor (arrows) that has been preloaded into the needle. B, a guidewire passed through the needle has pushed the anchor out of the needle’s tip. C, the introducing needle has been withdrawn, leaving the anchor and a guidewire within the gastric lumen. After the anchor’s attaching suture is secured to the skin, the procedure will continue. 116

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1990

FIG 34. A no. 10 French gastrojejunal ament of Treitz. Injection of ideal position for a feeding bowel without reflux back into .ains from the dal contrast

FIG 33. A, a curved duodenum. B, a loop-type catheter in fourth portion catheter is tostomy.

cannula has been used to direct a guidewire into the Note the vrscerostomy anchor at the lateral entry site. catheter has been placed. The loop will anchor the the stomach. Infused feeding solutions will enter the of the duodenum, as shown. On the right, a Malecot seen in the gallbladder following a surgical cholecys-

immediately as a decompressive gastrostomy. Generally, it is prudent to wait at least 24 hours after placement of the gastrostomy before tube feedings are initiated. Although not necessary in the majority of cases, contrast studies may be performed through the gastrostomy tube prior to initiating feeding to exclude the possibility of any leakage of gastric contents into the peritoneum. Although no. 10 French tubes are adequate for decompression and initial feeding, long-term gastrostomies are usually of a larger caliber, and increasing the tube size is mandatory if a liquefied diet is to be used on a long-term basis or if largebore tubes providing both gastric decompression and jejunal feeding are to be used. After the tract has matured for at least 2 to 3 weeks, tubes of increasing size may be substituted. Tract dilatation may often be accomplished directly by passage of these tubes. Alternatives include tapered dilators of the Amplatz (Cook, Inc.) type or a tract balloon like those intended for the development of nephCurr

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1990

feeding contrast catheter: an atonic placement

catheter with its tip at the ligdemonstrates why this is an the infusate fills only small stomach. (NOTE: gastric funprocedure.)

rostomy ts. Simple gastrostomy tubes (e.g., Foley or MaLecot catheters), transgastric jejunal tubes (e.g., Carey-Alzate-Coons jejunal tube [Cook Inc.]), or specialized tubes such as the Rombeau gastrostomy-jejunostomy tube (Ivac Corporation, San Diego, California) may be placed, depending on the needs of the individual patient (Fig 35). Complications occur, but most are minor and cause no symptoms. VanSonnenberg et al. re-

FIG 35. A Carey-Alzate-Coons transgastnc jejunal tube is seen in positron. Note the Cope viscerostomy anchor (curved arrow) that was used during the initral placement of this tube. The tube itself also has small wrngs (straight arrows) to prevent Its backing out of the stomach. The infusing tip lies well into the jejunum, essentrally eliminating any chance of gastric reflux. 117

FIG 36. A, PIercL junal I ani the t3allc (arrc IW). pass ;ing

118

rtaneous rnfubatron of a proximal jejunal loop. A catheter passed, through the mouth, esophagus, gastric remnar 1t and g astrojeastomosis is injecting contrast into the efferent jejunal limb. B, a balloon-tipped catheter has been placed in the bowel Ic)op and Ion Inflated with dilute contrast to allow easy fluoroscopic localization. The tip of a Chiba needle is seen just bf ?Il)w the balloon A platinum-tipped mandril, or stiff wire guide, with a diameter of 0.018 in. has been passed through the Chib a needle : and is retrograde Into the bowel loop. C, by use of the Cope micropuncture system, access has been increased frc In n the 01.018-in.

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ported a 5% incidence of major complications and an 8% incidence of minor complications in their series.56 In a detailed review of 5 years of experience, Halkier et al. found major complications necessitating surgery in 1.2% of their patients as well as a 0.4% incidence of major hemorrhage.“8 They also reported a 30-day mortality rate of 14.2%, including procedural deaths in 0.8% of cases-excellent figures given the general debilitation of their population.58 Actual dislodgement of the catheter with peritoneal spillage of gastric contents is quite uncommon. Inadvertent puncture of the left lobe of the liver or of another viscus is generally easily avoided by performing a careful ultrasound examination just prior to the procedure. In cases deemed especially risky, CT guidance can be used to guide placement of the initial needle or trocar. Intraperitoneal air or small abdominal wall or gastric wall hematomas may be commonly seen on follow-up CT scans but are not usually associated with any symptoms or change in clinical status.5Y

PERCUTANEOUS LOOPS

INTCJBATION

OF SMALL BOWEL

Occasionally, small bowel loops may be intubated in a fashion almost identical to that previously described. Although the clinical indications are less well defined, patients with obstructed afferent loops or other focally dilated areas of small bowel may be successfully catheterized using techniques similar to those described.60-63 In selected cases, a particular loop of bowel may be accessible through the mouth or a preexistent stoma. In such cases, local injection of air and contrast medium may be used in combination with C-arm fluoroscopy to guide safe puncture (Fig 36). Since the small bowel is normally collapsed, distention with injected air and contrast medium should be augmented by the use of IV glucagon. In most cases, a Chiba needle approach is preferred, since it permits a relatively safe exploration of the abdomen. If the free peritoneum or uninvolved loops of bowel are accidentally entered with the thin needle, the risks are extremely small, and the exploration may be continued under fluoroscopy until the appropriate loop has been safely entered. Interactive ultrasound or CT guidance is extremely helpful in minimizing trauma to uninvolved loops of bowel or the free peritoneum (Fig 371. Once safe access is gained, a variety of tubes

may be passed through the enterostomy and used for decompression, enteric feeding, or a combination of the two. PERCUTANEOUS

CECOSTOMY

Although an unusual procedure, percutaneous cecostomy can be life saving in selected instances. In the vast majority of cases, the cecum will be grossly distended secondary to distal obstruction, volvulus, or other conditions, and CT guidance, although useful, is not mandatory.64 Computed tomography is essential for those cases in which the cecum is not markedly distended and displays some degree of mobility.6” The cecum is punctured directly by percutaneous approach. The point of the cecum located most tangent to the abdominal wall is selected and the puncture is generally made through the anterior axillary or midaxillary line. Although the initial puncture may be made with a trocar system, a thin needle puncture using the Cope system is generally the simplest. Since cecal decompression must usually be carried out over an extended period of time, the risk of fecal spillage into the abdominal cavity must be considered. Following the initial puncture, the cecum may be drawn up against the abdominal wall by using a loop type of catheter or a catheter of the sliding Malecot type. Alternatively, anchoring devices such as the Cope viscerostomy anchor may prove extremely usefu1.17J 57 Viscerostomy anchors allow a more rapid dilatation of the percutaneous access tract so that large-bore decompression tubes can be placed more rapidly. Extensive instrumentation of the cecum is generally not indicated at the time of the initial puncture. Most cecal decompression is simply meant to relieve gaseous distention and minimize the’risks of cecal rupture. Even a very small-bore tube is generally suitable to this task. If abundant liquid stool fills the cecum, a more aggressive approach will be necessary, and placement of no. 10 to 16 French tubes may be required to achieve adequate decompression over the long term. GASTROINTESTINAL

DRAINAGE

PROCEDURES

DRAINAGE OF ABSCESSES WITH PERSISTENT ENTERIC COMMUNICATION General Considerations Drainage of collections having persistent connections with the gut lumen poses some special

guide to a 0.038-in. guide. An 18-gauge needle passed over this has been used to place a viscerostomy anchor (arrow) in the air-fllled bowel loop. D, with the bowel loop secured to the anterior abdominal wall, the hole has been further enlarged and a no. 8 French loop catheter placed in the ]e]unum. Infusion of feedlng solutions may be safely begun withln 24 hours

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119

FIG 37. A, obstruction of the afferent limb was suspected on clinical and radiologic grounds in this patient with recurrent gastric carcinoma. Percutaneous drainage was requested for palliation. B, the drlated afferent limb with dependent debris was easily identified on ultrasound examination. A safe puncture site was chosen beneath the liver edge. C, Chiba needle puncture and injection of a small amount of water-soluble contrast allowed almost the entrre loop to be imaged fluoroscopically. A safe and appropriate site for definrtive drainage was t&n chosen, and the loop was decompressed

120

problems that may require alterations of standard abscess drainage techniques.6” In most cases, the initial drainage procedure should be performed in a standard fashion. Occasionally, a persistent connection to the GI tract will be appreciated at the time of the initial diagnostic study or during the drainage procedure itself. Often, however, such a connection will become apparent only on followup examinations.67 The severe inflammatory reaction and edema associated with many abscesses may obscure connections that become apparent once percutaneous decompression has been accomplished. However, in some cases, such connections are particularly subtle. Demonstrating them may be quite difficult and may not be accomplished for many weeks. Despite extremely high accuracy in defining anatomic relationships, CT scanning, like other forms of cross-sectional imaging, suffers from some inherent difficulties in precisely defining the threedimensional anatomy of a complex abscess cavity. Many abscess cavities examined only with CT demonstrate “loculations” that are more apparent than real. These apparently discrete locules have a continuity that is readily demonstrated once contrast material is injected and the patient is examined under fluoroscopy. The possibility of an occult persistent communication should always be raised when an abscess cavity fails to resolve normally. Given good dependent drainage, effective evacuation of all associated collections, and appropriate antibiotic therapy, most abscess cavities should show significant healing within 1 to 3 weeks after a percutaneous drainage procedure.68 When an abscess fails to heal or shows persistent drainage of purulent or feculant material, the cavity should be actively explored. It should be assumed that there are one or more occult communications that are effectively resupplying the cavity with purulent or contaminated material. Complete filling of the cavity with radiographic contrast, followed by fluoroscopic examination and filming in multiple projections, is the first step and may show internal pointing toward the communication6’ A detailed examination of this sort should not be undertaken at the time of the initial drainage due to the risks of bacteremia and, possibly, septic shock. If a fluoroscopic search proves fruitless, exploration may be undertaken with torqueable catheters and guidewires. Either a flexible sheath in combination with a precurved torque guide (e.g., Lunderquist-Ring torque guide) or a precurved catheter’ such as an MPA (multipurpose catheter) or a cobra can be used (Fig 38,A). Under direct fluoroscopy, the guides and catheters are used to probe the multiple separate recesses of a complex collection. Great care should be taken when any of these Curr

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FIG 38. A, this large,

postoperative, right paracolic collection had not tional support. This course prompted fluoroscopic exploratron, into a second abscess cavity (arrow), which had not previously another tract, this one leading to a leak in the afferent limb of a chosen for drainage. A T tube is usually not required for a leak pose a risk of high-volume drainage.

resolved during been Bilroth of this

instruments are used to explore a cavity or fistulous tract, since the fact that they can be torque controlled requires that they be relatively stiff. Necrotic portions of the cavity wall as well as associated granulation tissue are extremely friable, and perforation with inadvertent extension of the abscess into uncontaminated spaces is always a risk. Frequent injections of water-soluble contrast medium should be made. Once a bowel mucosal pattern is identified fluoroscopically, spot films are taken in multiple projections to define the connection (Fig 38,B). After the communication with the alimentary canal has been demonstrated, it is essential that flow through this leak be controlled. A drainage tube should be placed directly into the fistulous track and, if possible, advanced somewhat into the bowel itself. The exact size and type of tube used depend on both the anatomy of the communication and the amount and nature of the bowel effluent (Fig 38,C). It is true that a tube passed completely through the bowel wall will effectively stent the perforation, preventing early healing; however, the primary therapeutic consideration should be diversion of all intestinal contents so that the abscess cavity or cavities that were originally entered can be effectively drained and allowed to heal. FreCur-r

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despite contrnuous drainage and vrgorous antibiotic and nutriwhich the catheter fell through an unappreciated communrcation demonstrated. B, further probing of the midline abscess revealed II anastomosis. C, in this case, a no. 14 French, rubber T tube was type, but the proximity to the gastric remnant (G) was thought to

quently, at least two tubes are required for this sort of drainage: one tube in the bowel lumen and at least one additional tube in the abscess cavity. With effective diversion, the abscess should respond ‘normally” and begin an obvious healing process. If closure of the abscess is still delayed, the search should be continued for additional communications with the bowel.

Common

Clinical Settings

Using the general principles just discussed, one can effectively manage a wide variety of enteric-associated abscesses by interventional radiologic methods alone. For example, diverticular abscesses have traditionally been managed by a twostage or even a three-stage approach, with surgical drainage and diversion being followed by resection of the diseased bowel and eventual reanastomosis. This sequence can be considerably simplified by substituting percutaneous drainage for the initial surgical procedure. Several series have reported excellent results with this innovative approach.70, 71 Similarly, periappendiceal abscesses occurring outside the context of an acute appendicitis have been successfully managed by percutaneous techniques alone.‘“’ 73 121

Perhaps the most surprising successes of all have occurred with the percutaneous drainage of abdominal abscesses associated with Crohn’s disease.74-76 Traditional wisdom dictates that these lesions will never heal and must be either clinically tolerated or surgically resected, the latter course carrying a discouragingly high risk of recurrence. However, the radiologic literature now contains reports clearly documenting healing not only of the abscess cavities but of their associated enteric communications as well (Fig 39). The implications of this finding as they affect the usual assumptions about abscesses, leaks, and inflammatory bowel disease are interesting. Two possibilities are immediately suggested. The first is that at least some types of Crohn’s lesions can heal in a manner approximating that of more normal bowel. Certainly, the usual manifestation of inflammatory bowel disease (i.e., foci of thickened, dysfunctional bowel with fistulas) is not one that appears conducive to healing of the sort reported. The second possibility is that some of the abscesses and fistulas occurring in the setting of Crohn’s disease are more “garden variety” than is commonly assumed. In other words, the leak may not be the direct re-

sult of a destructive, transmural inflammatory process, but rather is a secondary result of a proximal or distal lesion producing ischemia or bacterial overgrowth. In any case, these encouraging reports have lengthened the list of those enteric abscesses that can be considered appropriate for percutaneous drainage.

Uncommon

Approaches

Occasionally, enteric abscesses may develop from rather straightforward pathologic conditions, but in locations that render the usual and customary techniques of access and drainage inapplicable or ineffective. This situation probably occurs most often in the pelvis, a common site for abscesses resulting from small or large bowel disease. Here, the bony pelvis, bladder, uterus, adnexae, and a close and complex arrangement of neural and vascular structures can make direct access to a collection difficult if not impossible. Some innovative approaches have been used successfully in this setting. Haaga and Beale injected gas (carbon dioxide) through their advancing drainage needle into the peritoneum, effec-

FIG 39. A, injection

of contrast into a right flank abscess in a patient with Crohn’s disease. This abscess occurred after resection of some small bowel. Note filling of Edematous and angulated ileal loops. One drain was placed in the collection, and a second was placed in the bowel lumen to prevent further leakage. B, after 6 weeks of catheter drainage, together with antibiotic support and bowel rest, the appearance has changed markedly. The abscess cavity and associated fistula have resolved, leaving only a small, smooth-walled connection to the bowel lumen. Equally dramatic is the change in the appearance of the bowel itself, which now looks essentially normal. This sort of response may indicate that these abscesses were garden-variety postoperative collections and not the result of inflammatory bowel disease. 122

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tively pushing intervening bowel loops out of the way as they approached pelvic collections.77 Equally adventurous was the introduction of a new posterior route through the gluteal muscles and the greater sciatic foramen. This technique is more difficult and has a higher risk of morbidity than more conventional routes, but it has permitted the successful treatment of lesions that were otherwise inaccessible. The possibility of using the lumen of the gut itself as a drainage route should be considered when a problem of difficult access arises. Since, in most cases, the adjacent bowel was the source of infection, it cannot be, a priori, considered an uninvolved space. The source of infection is, in fact, of little consequence; since the enteric lumen is, to a greater or lesser extent, depending on location, populated by a variety of microorganisms, it cannot truly be contaminated by passing a drainage catheter through it. Surgeons have long used a transrectal approach to incise and drain abscesses in the cul-de-sac or presacral space. The radiologic approach is simple and straightforward.7s’ So Computed tomography or ultrasound scanning prior to drainage is essential to ensure that nothing is interposed between the rectal wall and the collection (e.g., the prostate in elderly men). If the collection is small, drainage is probably best carried out under CT or ultrasound guidance. However, if the collection is large, it will protrude into the rectum and be easily visible fluoroscopically. The patient is placed in a lateral position on the fluoroscopic table with the knees drawn up against the chest, and air is instilled into the rectum. Care should be taken when the puncture needle or trocar is passed through the anal canal. The puncture should be made in as short and direct a path as possible, and the track should be immediately dilated to a size sufficient for the subsequent passage of the drainage catheter. Since drains passing through the anal canal are both uncomfortable and difficult to maintain, the drain should, if at all possible, be well anchored within the collection. The Cope loop configuration may be used to advantage here, and the soft materials (e.g., polyurethane) from which these tubes are commonly made will be better tolerated than stiffer plastics. As usual, the size of the drain should be chosen according to the volume and viscosity of the material to be drained; generally, a no. 12 to 14 French tube is indicated. A similar approach through the vagina can be employed for draining collections in the midpelvis of women. Although access through the vaginal fornices is routine for gynecologists who perform colposcopy, it is unfamiliar to most interventional radiologists. As with the transrectal approach, precise definition of the relationships of the pelvic visCur-r Probl

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cera to each other as well as to the abscess is essential prior to beginning the procedure. Actual needle passage may be difficult to carry out under CT guidance since the dorsal lithotomy position that is optimal for exposure is difficult to achieve within the confines of a CT scanner. Ultrasound guidance is therefore preferred, or in the case of extremely large collections, puncture can be safely performed under fluoroscopy. As noted before, secure anchoring of the drain within the collection is probably best achieved with a Cope loop or similar self-retaining catheter. At the opposite end of the gut, the esophagus, stomach, and duodenum may also serve as minimally traumatic routes of access for drainage of paraenteric collections. As in the distal gut, both spontaneous perforation and postoperative leaks and abscesses may occur. The majority of collections found after gastric or duodenal surgery can be directly approached by conventional percutaneous routes. It is the exceptional lesion that requires a transluminal approach. In such cases, intubation of the viscus is carried out as described earlier, and the tube tip is then manipulated through the hole in the bowel wall and into the collection. A creative approach is essential, and both percutaneous and transluminal techniques can be combined in selected lesions. A technique analogous to that for the transgastric drainage of pancreatic pseudocysts can be used?l Since the stomach is easily entered percutaneously, it may afford a better approach to a collection outside the stomach or duodenum than either a purely percutaneous method or intubation via the esophagus. The principal technical challenge in these cases lies not in the initial catheterization and drainage, but rather in maintaining the drainage tube within the extraenteric cavity. For the most part, there are no commercially available self-retaining drains of sufficient length to serve this purpose. However, with an appropriate length of tubing and some suture, a reasonable and functional facsimile can be handmade.“’ In contradistinction to most gastric and duodenal leaks, esophageal leaks, in general, are not easily approached percutaneously. If the collection is large and dissects along tissue planes, it may reach a point where it can be safely entered percutaneously. However, smaller collections or those limited by surgical disruption of normal tissue planes may be approached only through the esophagus. The approach is usually straightforward, being essentially an extension of the standard techniques of esophageal intubation (Fig 40). Of course, if long-term drainage is needed, the tube must be passed through the nose and not the mouth. As already observed, securing the tube may present the greatest technical challenge. Al123

FIG 40. A, an esophagram

performed following surgery complicated by postoperative fevers shows a leak from the distal esophagus (arrow). B, a guidewrre and catheter have been passed down the esophagus and are seen as they enter the abscess. Injected contrast gives a better idea of the extent of the collection than could be gained by a routine esophagram. The catheter was passed through the nose since thus IS the route used for long-term drainage. C, a no. 10 French drainage catheter has been secured within the abscess with a Cope loop lockrng device. Larger tubes are usually not needed for esophageal collections, which generally contain relatively thin, purulent material. Despite the unusual route of access, the management of these abscesses is like that of any other abscess. (From Meranze SG, LaVeen RF, Burke DR, et al: Transesophageal drainage of mediastinal abscesses. Radiology 1987; 165395-398. Used by permission.)

though few drainages of this type have been reported, the procedure is a sensible one that avoids the considerable risks of surgical drainage of the mediastinum and appears to be successful in the majority of cases.83’ 84

DRAINAGE OF ABSCESSES 7 : !:ZOCJGH FISTULOUS TRACTS If a fistulous tract already exists between an abscess and the skin, neither ultrasonography nor CT is necessary to guide the initial drainage, and in fact, simple contrast fistulography is the study likely to provide the most helpful information.85 A fistulogram is first performed by directly injecting contrast mate&l into the tract (Fig 41,A). If the opening is small, a tapered catheter adapter can be used; if the opening is large, a red rubber tube can be advanced into it a short distance, or a fully inflated Foley or similar balloon catheter can be 124

used to obturate the opening, allowing more effective filling of the sinus tract.86 After the anatomy is defined as well as is possible, the tract is cannulated. Since many fistulous :racts are extremely friable, and the danger of creating a false passage is always present, the softest possible instruments should be used. Generally, a red rubber catheter with one or more large added side holes should be tried first. If necessary, the rubber can be coated with a water-soluble surgical lubricant and then advanced into the tract with a gentle spinning motion, that allows the soft rounded tip to find its way along the tract. Frequent injections of water-soluble contrast medium are used to define the anatomy of the tract and disclose any branching points. Spot films should be taken in multiple projections to map the fistula or fistulas. If the fistula is particularly stenotic, or if acute bends make passage of a red rubber tube impractical, a torque-controlled guidewire and a small Curr

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FIG 41. A, a dragnostic

fistulogram performed in a patient with progressive deterioration following what appeared to be routine surgery for duodenal ulcer. A right lower quadrant Penrose drain produced copious quantities of fluid. The tract has been injected. A small catheter was introduced at the cutaneous stoma (arrow), and contrast fills a long tract, terminating in an irregular collection in the right upper quadrant (arrowheads). B, using spot films taken during the diagnostic fistulogram and frequent contrast injections under fluoroscopy, the operator gently advances a guidewrre and catheter through the fistula. The wire’s tip has entered an abscess cavity.

catheter (e.g., 5 French Teflon sheath) can be advanced directly through the tract (Fig 41,B). If a stiff torque guide such as the Lunderquist-Ring guidewire is used, the guide should be advanced only under continuous fluoroscopic guidance while it is rotated continuously and only the gentlest forward pressure is applied. Some of the newer soft-tipped vascular torque guides (e.g., Wholey or TAD guidewires [PSG, Mountain View, Calif]) are probably safer in this setting. The wire should be removed frequently and water-soluble contrast medium gently injected to assure that the catheter and wire remain in the true lumen of the fistula and have not created a false passage. Use of a Touhey-Bourst or similar device to allow contrast medium injection around the guidewire may provide an extra margin of safety, as may the use of a digital roadmapping system.87 Small collections can be adequately drained with small (i.e., no. S-10 French1 pigtail or looptype catheters. Larger collections may require drains as large as no. 12 to 14 French or greater. If the contents of the cavity are particularly thick and purulent, or if continued communication with the bowel is known or suspected, a sump (i.e., two-lumen1 drain probably provides the best Curr

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method of initial drainage. The choice of tube for drainage of the bowel itself depends on the size of the perforation and the volume of fluid in the bowel lumen. In most cases, a simple red rubber drain will suffice, but occasionally, active sump drainage may be necessary. Since complete drainage may require side-byside placement of multiple tubes, portions of the tract may prove too stenotic to permit adequate passage of the drainage catheters. Once a guidewire has been passed through the fistula, either coaxial biliary dilators or (preferably) tract-enlarging balloon catheters can be used to provide an adequate channel and permit passage of tubes of the appropriate size.

MANAGEMENT FISTULAS

OF ENTEROCUTANEOUS

An enterocutaneous fistula is any cutaneous drainage tract that communicates directly with the bowel lumen. Several diverse types of pathology are grouped under this heading, and consequently, there is an appropriate diversity of management techniques. 125

Low-Output

Enterocutaneous

Fistulas

Enterocutaneous fistulas that produce less than 200 mL of drainage daily and are not associated with extensive abscess formation generally present few management problems. The success of conservative therapy is high and the corresponding mortality low.88 Often, such fistulas are discovered incidentally when a routine surgical drain is removed and the cutaneous opening fails to heal. Radiographic exploration of the tract is undertaken as described earlier, and the fistula is intubated (Fig 42,Al. If no abscesses are associated with

the tract, a simple straight drain (i.e., red rubber catheter) is placed just outside the opening in the bowel wall, and the tract is allowed to heal. Generally, most tracts will mature within 2 to 3 weeks, and the drainage catheter can be gradually withdrawn.” If abscesses are associated with the tract, they must be drained. When necessary, the tract should be enlarged to accommodate the appropriate number of drainage catheters (Fig 42,B and Cl. Straight catheters or loop drains are adequate for most collections. If the collection is particularly

FIG 42. A, persistent,

low-volume drainage (i.e., less than 100 mU24 hours) had complicated the postoperative course of this woman after resection of diseased shall bowel. Injection of the fistula demonstrates its connection with a loop of bowel (arrow) as well as filling of an assocrated abscess cavity. B, a simple drainage catheter was easily passed into the distal portion of the abscess cavity. However, because the tract was small, access to the more proximal leak has been lost. C, after enlargement of the tract, two drainage tubes (arrows) can be accommodated. One tube can drain the more distal abscess, and a second can control continued leakage from the distal small bowel. D, the abscess has resolved, and injected contrast fills only a small residual connection and the bowel. This tube (arrows) will be exchanged for a smaller one, which WIII be gradually withdrawn from the tract. 126

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large or contains thickly purulent material, sump drainage may prove more effective. Once isolated from the bowel lumen, the abscesses are managed in a routine fashion, and the drainage catheter is removed once the cavities have healed. After all of the associated abscesses have resolved, the fistula drain itself is gradually withdrawn from the tract (Fig 42,D).

High-Output

Enterocutaneous

Fistulas

Many fistulas that originate in the duodenum, jejunum, and ileum are classed as high-output fistulas. To be termed high output, the drainage volume needs to exceed only 200 mU24 hours, but many of these drain as much as 4,000 mL of intestinal contents each day.8’ The management problems posed by such massive losses of fluid, electrolytes, and nutrients are formidable and are frequently complicated by the presence of one or more intra-abdominal abscesses. Fluoroscopic exploration of the fistula is undertaken in the manner already described. Frequently, multiple tracts interlace beneath the skin in a complex fashion, and familiarity with their relationships is critical when one is attempting to drain the system effectively. Surprisingly, despite their high output, many of these fistulas show no direct point of communication with the bowel lumen when first examined. The tortuous fistulous tracts are often seen to communicate with large irabscesses). All regular spaces (i.e., communicating

FIG 43. Schematic representation of a high-output enterocutaneous frstula. A curved catheter is exploring a tortuous tract (T) to find the source of leakage. A point off the tract leads to a large abscess cavity. This is a sentinel abscess @A), which lies immediately outside the leak In the bowel loop (6). (From McLean GK, Mackie JA, Freiman DB, et al: AJR 1982; 138:615-619. Used by permission.) Cur-r

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abscesses imaged should be carefully entered and explored since there is frequently a “sentinel abscess” near the site of bowel perforation (Fig 43). Access to the bowel lumen is then gained by traversing the abscess cavity with a catheter. Great care should be taken not to probe the tract or abscess cavities too vigorously since the surrounding tissues are necrotic and friable; false passages are easily formed and will confuse an already difficult topography. If the point of communication of the fistula with the bowel is not apparent, the largest extraenteric collection or most central part of the tract is cannulated and drained. Over the next few days, fluoroscopic exploration of the fistulas and abscess cavities is continued until the point of communication with the bowel is identified (Fig 44,A and B). For many enteric fistulas, T tubes are an ideal drainage catheter. Their configuration securely anchors the tube in the bowel, and once adequate side holes have been added, the horizontal limbs can divert much of the flow of intestinal contents from above and below the site of perforation (Fig 44,C). The technique for placing a T tube in the bowel is essentially the same as that used for the common bile duct.“’ s1 The appropriate tube diameter can usually be estimated from a diagnostic fistulogram. It is better to slightly underestimate the size needed rather than to risk enlarging the hole in the bowel wall by placing an oversized tube. Once the initial tube has been placed, it is relatively simple to insert larger tubes at a later date to provide better drainage of intestinal secretions. The horizontal limbs of the T tube should be about 5 to 8 cm long, and side holes should be cut in both limbs to assure adequate drainage of the bowel loops. If the hole in the bowel wall is small, direct placement of a T tube will be difficult ‘and, possibly, counterproductive. In such cases, bowel contents can be effectively diverted through a straight tube of appropriate diameter. A heavy duty exchange guidewire (e.g., Amplatz exchange guide) is advanced well into the bowel lumen, and the intraluminal tube is introduced over the wire. In most cases, the tube can be advanced directly over the wire until both limbs enter the bowel. If there is difficulty in introducing the tube (especially likely with T tubes), both the guidewire and tube are advanced together as a unit. Once a few centimeters of progress has been made, the tube is held in position, and the guidewire is withdrawn to its original location. This procedure is repeated until a sufficient length of the tube has passed into the bowel lumen. If a T tube has been used, the guidewire is removed, and gentle traction is applied to the external limb of the T, causing the tube’s apex to move back to the hole in the bowel wall and bringing the horizontal 127

FIG 44. A, the guide has passed through an abscess and now follows a course corresponding to that of the duodenum. Note that the soft tip of the wire allows it to buckle forward through the bowel lumen. Using atraumatic gurdes such as thrs is essential to avoid perforatrng the friable wall of the fistula and creatrng false channels (same patient as in Figure 41). B, the actual site of leakage has been identified along the superior aspect of the third portion of the duodenum. The diagnostic catheter passed through the fistula is seen (arrowheads) wrth its tip lust wrthin the bowel lumen. Injected contrast fills the duodenal sweep and outlines a nasoentenc tube that had been passed previously (arrow). C, a ‘r tube has been placed in the duodenum through the fistula. Note how the shape of the tube corresponds perfectly to the anatomy. The tube’s sidearms are in ideal position for passive drainage of luminal contents, thus providing maximum protection to the healrng fistula. (C from McLean GK, Mackie JA, Freeman DB, et al: AJR 1982; 138:615619. Used by permission.)

FIG 45. Technrque of passrng a T tube through a fistula into the bowel. A, a heavy-duty guidewire has been placed well into the bowel lumen. The back end of the wire has been passed through one of the sidearms of the T tube and out its long or external limb. The tube is being advanced over the guide, and the leading sidearm enters the cutaneous stoma. B, the T tube is placed in the bowel either by slrding it drrectly over the guide or by advancing both tube and wire as a unit (described in the text). The tube must be advanced until the back of the trailing limb (curved arrow) has passed into the lumen. C, by gently pulling back on the external lamb of the ‘1‘ tube, the operator moves the trarlrng lamb Into proper alignment as shown. (From McLean GK, Mackre JA, Freiman DB, et al. A& 1982, 138.615619. Used by permission.)

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limbs into proper alignment (Fig 4.51.Water-soluble contrast material is injected through the tube to confirm proper location in the bowel. Some of the injected contrast material will probably leak around the tube into the proximal part of the tract. This should not be a cause for concern, since a straight or sump drain may be placed outside the hole in the bowel wall to control any leakage. The tube is connected to a straight drainage or low intermittent suction. Periodic inspection and injection of the tube should be performed under fluoroscopy to see whether any alterations in its size or position are indicated. Additional drains are used to control leakage of intestinal contents around the intraluminal tube as well as to drain any associated abscesses. The high volume of output associated with most enterocutaneous fistulas mandates the use of sumptype drainage in a majority of cases. Sump tubes designed for placement over the guidewire (e.g., Ring-McLean Sump [Cook, Inc.11 generally work best since they can be more precisely placed in the tract and its associated abscess cavities. Small collections that become effectively isolated from the bowel once the intraluminal tube and its associated drains are placed can be controlled with

simple loop-type catheters. The management of abscess occurring in association with a high-output enterocutaneous fistula is identical to that used for any other abscess cavity once control of the fistula has been obtained (Fig 46,A and Bl. The placement of a large-bore tube directly in the bowel, combined with sump drainage of the tract adjacent to the opening in the bowel, should permit complete diversion of the intestinal effluent. After a few weeks of combined intraluminal tube and sump drainage, the volume removed through the backup sump will gradually decrease to extremely low levels (i.e., less than 50-100 mW 24 hours1 as the bowel wall heals around the tube. If the intraluminal drain is clamped too early, there may be an abrupt increase in the volume of sump drainage, and bowel drainage must continue. Once clamping is well tolerated, the intraluminal tube is removed, and the sump drain is placed just outside the bowel. As the volume of sump drainage decreases, the sump is gradually advanced out of the tract. Straight red rubber drains may be substituted for sump drains as the fistula healing progresses (Fig 46,Cl. Drainage of all fistula-associated abscesses must be concurrent with therapy of the fistula itself.

FIG 46. A, management

of abscesses associated with a high-output fistula. The T tube placed In the bowel (arrowheads) has effectively dlverted continued outflow. Two abscesses are associated with this leak: a small collection immediately outslde the duodenum (7) and a second abscess (2) in the retroperitoneum. A catheter has been manipulated Into the more dependent collectton prior to passing a dralnage tube (same patient as In Figure 41). B, with effective dtversion of the Intestinal effluent and good drainage, the cavltles have largely resolved. The upper abscess is gone, and the more dependent space has shrunk to the size of the dralnlng sump catheter. At this point, a smaller, passive drain (i.e , gravity drain) will be substituted for the sump catheter, and this will gradually be wlthdrawn as healing progresses C, all abscesses have resolved, and only a small, smooth tract to the bowel remains (a matured, external flstula) The sump drain IS not needed, and a small red rubber tube has been substituted for It lntermlttent clamping and gradual withdrawal of this tube will complete the treatment of this fistula. (From McLean GK, Mackie JA. Freeman DB. et aI, AJR 1982, 138.615619. Used by permission ) Cum

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129

It should be emphasized that these patients are not easy to manage, and the results of conservative therapy come slowly. The complete exploration of multiple interlocking fistulous tracts and abscess cavities usually requires numerous trips to the fluoroscopy suite over many days. High-output enterocutaneous fistulas tend to drain for prolonged periods. Tubes will repeatedly become obstructed or dislodged and must be replaced. The management of these lesions may be more protracted than that of any other encountered by interventionalists. However, with time and a great deal of

patience, a surprising number of high-ouput enterocutaneous fistulas can be healed by means of interventional radiologic therapy alone.6s Of course, not all patients respond to such conservative therapy. Surgery is almost always indicated in patients with obstruction distal to the leak, those with an end fistula (i.e., lack of bowel continuity), those whose fistulas result from a malignancy, or those who fail to heal after an adequate trial of conservative therapy.87 Even in such cases, however, controlling intestinal output and decreasing the inanition and continuous infection associated with fistulas and abscess cavities will help to stabilize the patient and greatly increase the chances of successful reparative surgery.

Enteropancreaticocutaneous

Fistulas

The combination of pancreatic drainage with an enterocutaneous fistula presents some unique difficulties. The proteolytic nature of pancreatic outflow will delay or even prevent the healing of many tracts.66 Despite the potent proteolytic nature of the effluent, in many cases effective drainage of enteropancreaticocutaneous fistulas can result in the complete healing of such tracts. The initial radiographic exploration of the tract and abscesses must be exceptionally thorough since the combination of pancreatic enzymes and high-output bowel effluent promotes extensive fistulization (Fig 47,A). Once a thorough appreciation of the morbid anatomy has been gained, and the appropriate tubes have been placed, management is undertaken as described earlier (Fig 47,Bl. The time required to effectively close such a fistula is considerably longer than that seen with less complex forms of pathology. The successful closure of an enteropancreaticocutaneous fistula and resolution of associated abscess usually take from 4 to 6 months. In spite of this prolonged course, an extended attempt at conservative tube management is warranted since surgical excision is complex and fraught with a high risk of abscess and sinus tract recurrence. REFERENCES

FIG 47. A, this patient,

who had undergone a partial pancreatectomy, now presents with a chronic drarning fistula Injection of the midline drarnage site has filled an irregular tract that communrcates drrectly with the restdual pancreattc duct (straa,ght arrow), a small collectron In the pancreatic bed (open arrow), and the stomach (curved arrow). 6, &small dram has been manrpulated through the fistula and the restdual duct end lies with its tip In a small collectton (arrow). Some contrast can still be seen entering the stomach. After 1 month of drainage, the retroperitoneal collection had resolved and the gastric fistula closed Drainage of pancreatic secretrons continued for 4 more months, wrth eventual closure of the frstula. 130

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