Percutaneous abscess drainage

Percutaneous abscess drainage

Percutaneous Stephen G. Gerzof, Abscess Drainage Richard percutaneous drainage G UIDED nal abscesses has become well of abdomiestablished as an in...

6MB Sizes 1 Downloads 157 Views

Percutaneous Stephen

G. Gerzof,

Abscess Drainage Richard

percutaneous drainage G UIDED nal abscesses has become well

of abdomiestablished as an interventional radiologic procedure in many centers. It offers an important simple alternative to traditional surgical drainage. It represents a practical integration of several of today’s radiologic procedures. High quality cross-sectional imaging in combination with percutaneous catheter techniques allows safe placement of abdominal drainage catheters. This simple method of mechanical drainage, when employed with systemic antibiotics, is successful in treating abdominal abscess without surgery in the great majority of cases. The abdominal abscess is a space-occupying lesion whose mass effect typically displaces surrounding structures and viscera to provide a safe “window” for percutaneous access.‘*2 Percutaneous drainage of these lesions is based on the following four steps: (1) Cross-sectional imaging is employed to demonstrate the abscess and its relationships to surrounding structures. (2) Based on these scans, a safe percutaneous route that avoids viscera, pleura, major vessels, and other vital structures is planned. (3) A diagnostic needle aspiration is then performed through this projected pathway to confirm the diagnosis and verify the adequacy of the route. (4) Following confirmation, a catheter is inserted, the abscess evacuated, and the catheter sutured in place to provide effective continuous drainage. From the Department of Radiology, Tufts University School of Medicine, Boston, Mass. Stephen G. Gerzof, M.D.: Chief. Body CT and Vltrasound, VA Medical Center, Associate Professor of Radiology, Tufts University; Richard Spira, M.D.: Instructor in Radiology. Tufts University; Alan H. Robbins, M.D.: Professor of Radiology, Tufts University School of Medicine, Chief; Radiology Service, VA Medical Center. Reprint requests should be addressed to Stephen G. Gerzof. M.D., Department of Radiology, VA Medical Center, IS0 South Huntington Avenue, Boston, Mass. 02130. 0 I98I by Grune & Stratton. Inc. 0037-198X/81/16014009$02.00/0

62

Spira,

and Alan

H. Robbins

DIAGNOSIS

OF AND

ABSCESS

WITH

CT

ULTRASOUND

An abscess is a fluid collection of water density that blends with surrounding tissues and therefore is usually not seen on conventional radiographs unless it contains gas. Sectional imaging, however, clearly shows its fluid nature. When organized, it generally assumes a spherical or elliptical shape with convex bordersm3 Although the majority of intraperitoneal abscesses are unilocular, loculation occasionally occurs in retroperitoneal abscesses, especially psoas abscesses. CT and ultrasound each display the abscess with its own characteristic signs.2 The CT signs of abscess include: (1) A soft-tissue mass with low density center (usually O-25 Hounsfield units).‘6 The margins may be smooth or ill-defined, depending on maturity of the abscess (Fig. 1). (2) The “Rind Sign,” a rim of peripheral enhancement that appears after infusion of intravenous contrast4”** It results from hypervascularity of dilated vessels in the inflamed abscess wall. (3) The presence of gas in the mass, either as a frank air-fluid level or in the form of multiple small bubbles. (4) Displacement of surrounding structures. (5) Edema of surrounding tissue planes. Sonographic signs of abscess are variable and depend on the homogenicity of the abscess contents and on scan techniquee2 They include: (1) an echo-free mass with good sound transmission (Fig. 2);‘,9 (2) occasional low level internal echoes that may layer dependently; and (3) a highly echogenic mass caused by microbubbles in the abscess.” When an air-fluid level is present, visualization of the deeper portion of the abscess may be impossible and the diagnosis may not be apparent.2,‘0 These ultrasound and CT signs are nonspecific and a wide range of diagnostic possibilities must be considered prior to needle aspiration.2*3 These include postoperative fluid collections, such as biloma, lymphocele, urinoma, seroma, or hematoma (mnemonic:BLUSH). In addition,

Seminars in Roentgenology,

Vol. XVI. No. 1 (January),

1981

PERCUTANEOUS

ABSCESS

DRAINAGE

63

Fig. 1. CT scan of lesser sac abscess. The abscess (A) displaces the stomach (St) ventrad and the splenic flexure caudad (therefore not seen on this scan) to provide a safe percutaneous drainage route (black arrow and electronic cursor mark1 from a point just below the left costal margin. To avoid the diaphragm, the needle enters from below and angles upwards. P. pancreas, Sp. spleen, L, liver.

consideration must be given to pancreatic pseudocyst (sterile or septic); cysts of other origin; fluid-filled hollow viscus, particularly distended stomach, small bowel, colon, or genitourinary structure; and primary or secondary neoplasms. Differentiation between septic and sterile fluid collections requires Gram stain or bacteriologic culture.” In a patient with fever, elevated

Fig. 2. with good Note how (arrowheads)

WBC, clinical suspicion of sepsis, and a fluid collection or mass demonstrated by CT or ultrasound, the most effective diagnostic method is needle aspiration. In this situation, our dictum is, “The shortest distance between two points is a straight needle.” Of course, due caution should be taken to minimize inadvertent needling of a normal fluid-filled viscus.

Liver abscess. (A) Transverse sonogram shows a 4 x 6 cm echo-free lesion (arrowheads) in left lobe of liver (L) sound transmission and irregular walls. Cursor marks (white dots) indicate cutaneous entry site, angle, and depth. stomach gas (St) obscures the left upper quadrant. LB) Midline sagittal sonogram localizes the liver abscess in a cephalocaudal direction.

64

GEFZ’OF.

L 00 P8cf

0

K A

/ “1

/iii?--

Fig. 3. Angiocatheter technique. (Al Diagram of Fig. 2A shows projected entry site (x), projected route (dotted line), and target point (+ j at the near side of the abscess. P, pancreas with calcifications. Ao, aorta, K. left kidney. (6) 20gauge Teflon sleeve needle with needle stop is inserted over planned route to appropriate depth. (Cl After insertion of J-guidewire, an 8-F dilator is passed over the wire. (D) An 8-F pigtail catheter is inserted over the wire and advanced until it engeges the far wall of the abscess. (E) The abscess is evacuated by manual syringe suction. The catheter is then sutured securely to the skin and connected to a closed biliary drainage system. (Fig. 3F on facing page).

SPIRA.

AND

ROBBINS

PERCUTANEOUS

ABSCESS

65

DRAINAGE

Fig. 3F. Follow-up CT scan 7 days later shows the pigtail catheter (arrow) in place with no residuum. Confirmation of complete resolution prevents too early catheter removal and possible recurrence.

PERCUTANEOUS

DRAINAGE

Selection Criteria Prerequisites for percutaneous abscess drainage include a well-defined unilocular abscess cavity. safe percutaneous access, concurring surgical opinion, and immediate operative back-up in case of failure or complication.’ Contraindications include abscence of safe percutaneous access, which in our experience is uncommon; internal septation, a relative contraindication since it can be overcome by the placement of a separate catheter to drain each loculation; and coagulopathy, also a relative contraindication. Once confirmed by needle aspiration, either surgical or percutaneous drainage of the abscess is usually necessary, since undrained abdominal abscesses have unacceptably high morbidity and mortality rates.‘“.‘3 Infected hematomas may be diagnosed by needle aspiration but the presence of solid clot is felt to require surgical evacuation (Birkett DH, personal communication). Route Planning Early in our experience with abscess drainage, using gray-scale ultrasound and a 2.5 min CT scanner, it was not always predictable which of the modalities would be better for imaging an abscess in a particular location. However, analy-

sis of our cases using modern equipment (Picker 8OL Digital Gray-Scale and Ohio Nuclear 2010 CT scanner with 2-set scan time) has clarified this issue. Rapid CT scanning clearly has become the diagnostic standard and is the imaging modality of choice for suspected abdominal and retroperitonal abscess.h,7x’4 It is more reliable in providing rapid and accurate diagnosis, particularly in the postoperative patient in whom retained barium, bowel gas, open wounds, stomas, suture lines, drain sites, and bandages often preclude contact ultrasound scanning or limit penetration of the ultrasound beam. Because of its encompassing image of the entire abdomen with detailed anatomic display of the abscess and all of the surrounding structures, CT is far better than ultrasound for route planning and for exclusion of concomitant disease.‘.” It is the only modality that images the bowel in relation to an abscess, a crucial factor in patients with intraperitoneal or interloop abscess, in whom the bowel must be identified in order to avoid perforation.237 Ultrasound alone has been adequate for diagnosis and route planning in retroperitoneal and renal abscesses.’ It is also useful in larger intraperitoneal abscesses, which are usualI) cnteroparietal in location, ie, lying in contact with the parietal peritoneum.‘5 CT is essential for diagnosis and localization of the small deep intraperi-

66

GERZOF,

toneal abscess. If CT is not available, barium studies may occasionally suffice to localize bowel displacement. Used in combination with the sonogram, these films often provide enough information for planning a safe route. In accordance with general surgical principles, an extraperitoneal route is preferred to a transperitoneal route for percutaneous drainage whenever possible.‘6 This is principally for ease in avoiding the small bowel, since there have been no complications related to the transperitoneal approach.’ Accordingly, with any abscess the projected percutaneous drainage route should be correlated with surgical anatomy and the well established operative approaches for that location.4S7X’7V’8 In planning the projected drainage route, there are three factors to consider: cutaneous entry site, angle of entry, and depth. They are meticulously planned prior to needling, based on the CT and ultrasound scans. Once selected, these three factors uniquely define a line in space. This line is now the projected drainage route that the radiologist follows with the aspiration needle. The entry site is marked on the skin and confirmed on a repeat scan. The angle of entry is measured from the scan with a goniometer (plastic variable angle measuring device available in most radiology departments). The depth is measured as the distance from the entry site to the near wall of the abscess. This distance is transposed to the aspiration needle with a needle stop in order to avoid perforation of the far wall of the abscess and disseminating the infection. Abscess

Aspiration

and Drainage

Although CT is superior for diagnosis and route planning, ultrasound tends to be superior for guidance during the catheter introduction procedure. It provides closer monitoring by multiplanar scanning and simultaneous imaging, making final guidance easier for the operator. The lack of ionizing radiation offers an element of safety important to the patient but even more so to the operator. Diagnostic

Aspiration

We have used a 25-30 cm 20-gauge Teflon sleeve needle for diagnostic aspiration of

SPIRA,

AND

ROBBINS

abscesses. We prefer it to the 22-gauge needle because the lumen of the latter is often too small to allow aspiration of thick purulent material. Rarely, when the diagnosis is in doubt or there is a major element of uncertainty in the route, we do use a 22-gauge needle for simple diagnostic aspiration. The skin at the entry site is sterilized and draped. Under local anesthesia, a 4 mm skin incision is made with a no. 11 blade. The incision is widened by blunt dissection with a curved hemostat. Using a rubber-shod Kelley clamp as a needle stop placed at the premeasured depth, the needle is inserted in a single pass, the clamp and stylet are removed, and a small sample (~5 cc) is aspirated for immediate Gram stain and culture.““’ It is essential to send specimens for anaerobic as well as aerobic cultures to avoid incomplete or incorrect bacteriologic diagnosis.*’ Prior to drainage, treatment with intravenous antibiotics is instituted. Appropriateness of antibiotic choice is corroborated by Gram stain and cultures.‘,*’ If the fluid is obviously purulent, drainage is immediately instituted, using either the angiocatheter or trocar catheter technique described in the next section. The drainage should be performed without moving the patient, lest any change in position alter the anatomic relationships and invalidate the preselected drainage route. If clear and sterile, the fluid is totally aspirated and the Teflon sleeve removed. However, if the aspirate appears indeterminate to inspection, the decision to either insert drainage catheters or simply aspirate and remove the Teflon sleeve must await the results of Gram stain. If one evacuates a fluid collection and then discovers it was infected, a catheter can no longer be inserted into the collapsed cavity.

Catheter Techniques The choice of catheter technique depends on the size, depth, easeof access,and location of the abscess.’ The less traumatic 8-French pigtail catheter is used for smaller, deeper abscesses, for abscessesclose to bowel, and for parenchymal abscesses (intrarenal or intrahepatic). The trocar catheter is used for larger, more superficial, nonparenchymal abscessesin which there is a wide safe percutaneous access.

PERCUTANEOUS

ABSCESS

Angiocatheter technique (Fig. 3). A 0.035 inch 80 cm floppy or J tip angiographic guidewire is inserted through the Teflon sleeve into The sleeve is removed, taking the abscess.4,7,22 care to avoid withdrawal of the tip of the guidewire from within the abscess. An 8-F angiographic dilator is passedover the guidewire to slightly widen the track. An 8-F multiple side hole pigtail catheter is then introduced over the guidewire into the abscesscavity, taking care not to advance the wire within the abscess.The pigtail tip, which straightens for introduction over the guidewire, immediately resumes its tight coil within the abscess.This prevents perforation of the far wall as the pigtail catheter is advanced into the abscessand resists accidental dislodgement. After removal of the guidewire, the abscessis completely evacuated by manual syringe suction, and the catheter is securely sutured to the skin. Trocar catheter technique (Fig. 4). This technique is initially the same as the angiocatheter technique with respect to route planning, localization, and diagnostic aspiration. However, rather than a guidewire, a catheter with a selfcontained stylet that has a cutting edge is employed.7.23*24 After removal of both the aspiration needle and its sheath, the skin incision is widened slightly and a 12- or 16-F Argyle Ingram trocar catheter (Sherwood Medical Industries, St. Louis, MO.) is inserted at the same site, angle, and depth as the immediately preceding aspiration needle.’ A Kelley clamp must bc usedas a needlestop to prevent perforation of the far wall of the abscess,since considerable force may be required to advance this wider catheter through the subcutaneous tissues. On entry into the abscess,the central stylet is carefully maintained in fixed position, somewhat like a guidewire, while the catheter is gently advanced over the stylet into the abscess.Slight resistance is felt when the catheter tip engages the far wall of the abscess.The stylet is then removed, the abscess evacuated by syringe suction, and the catheter sutured in position. Subsequent

67

DRAINAGE

Management

In both techniques, the catheter is connected to a closed biliary bag collection system left to gravity drainage only. The catheter is taped securely in place to avoid traction by the bag.

Complete evacuation of the abscessshould be documented by repeat imaging studies. The position of the radiopaque catheter is also documented by AP and lateral radiographs. Once in position, percutaneously placed catheters are managed somewhat like surgically placed drains. However, irrigation is usually unnecessary since purulent material does not clot. Daily drainage volumes are charted to evaluate progress. The catheter is removed when clinical response(temperature and WBC count return to normal), cessation of drainage, and follow-up scans indicate complete resolution. This averagesaround I O-l 4 days.’ Sinograms arc usually not required except when follow-up scan demonstrates persistent residuum, significant drainage continues beyond 5-7 days, or an enteric tistula is suspected as the underlying cause of the abscess.Sinograms should be performed with low pressure by hand injection under close fluoroscopic control to avoid rupture of the abscess. DISCUSSION

Percutaneous abscess drainage is ;L logical extension of the radiologic techniques in sectional imaging and catheter placement and is considered conservative compared to surgery. At first it appears to be a striking departure from the universally accepted but heretofore unchallenged operative methods of abscessdrainage. However, it does in fact adhere to basic principles of surgical management by effecting decompression, evacuation, and continuous drainage without dissemination of sepsis. Furthermore, more percutaneous drainage routes closely follow the recommended operative approach to abscessesin similar locations.7 Despite the fact that wide operative incision and drainage is not established, successin over 90% of intraabdominal abscesses indicates that small percutaneously placed catheters provide adequate drainage.’ It cannot be overemphasized that thorough correlation with clinical data and other radiographic studies is essential prior to diagnostic needle aspiration. Percutaneous abscess drainage has several advantages over operative drainage. They include: (1) avoidance of surgery, general anesthesia, and related perioperative complications; (2) significant saving of time and expense; (3) better patient acceptance; (4) easier nursing

Trocar catheter technique. IA) Oiagrsm of Fig. 1. Aspiration needle is in position. The depth to the Fig. 4A-F (this page). near side of the abscess has been transposed to the aspiration needle with a rubber-shod clamp. (8) The aspiration needle is inserted in a single pass over the planned route. H.3 A small sample of material is aspirated for immediate Gram stain. (D) Trocar catheter in position. Note that the trocar catheter is being inserted from below upwards to avoid the diaphragm. A direct intercostal approach may transgress the pleura, causing pyopneumothorax. IE) The trocar catheter is advanced in a single motion into the abscess over the preselected route. (F) After removal of the clamp, the central stylat is held fixed in position, while the outer catheter is gently advanced over the stylet. Tha catheter should slide easily until slight resistance indicates it has engaged the far wall. During this maneuver. the central stylet functions as a guidewire. Note: care muSt be taken not to advance the cutting edge of the stylet to avoid perforating the far watt. Fig. 46-I (facing page). IG) Stylet is removed and the abscess is manually evacuated by syringe suction. The catheter is sutured 88cUrely t0 the skin with two 1-O silk sutUr8s. and the catheter is connected to closed biiiary bag drainage, With decrease in mass effect (arrows). the surrounding structures return to normal position and close the percutaneous access window. The catheter must now be protected against inadvertant fallout, since reinsertion may be impossible. (H) Follow-up CT scan shows catheter (arrow) with a small residuum (A), The OutermOSt portion of the catheter iS not seen. since it lies below the scan plane and was inserted from below upwards. The catheter remained in place for several days until complete resolutiOn Of the cavity and was than removed. (1) Follow-up scan 1 yr later shows complete resolution. Note the normal close relation of the stomach (St). spleen (SpL and splanic flaxure (CL Displacement by the abscess is required for percutaneous access to this area. Arrowhead indicates linear fibrous scar of previous drainage route.

Fig. 46-l.

See

legend

facing

page

70

GERZOF,

care, since frequent change of absorbent bandages is replaced by the closed collection system; (5) earlier diagnosis and treatment, which may account for the decreased morbidity and mortality; and (6) a lower recurrence rate.7 These last two factors are in part due to the nature of noninvasive imaging, which defines the full extent of the abscess prior to drainage, views the entirety of the abdomen to exclude concomitant abscesses and other abnormalities, and will demonstrate undrained residuum prior to removal of the drainage tube. Using this methodology we have not yet encountered any recurrence.7s’2 From our experience with over 70 cases, we have reached several important conclusions: (1) The procedure is best performed by those who are experienced in cross-sectional imaging and who are skilled in guided needle biopsy, aspiration, and Seldinger techniques. (2) Percutaneous accessibility of an abscess is determined by its size and location. The larger and more superficial the abscess, the easier the percutaneous access. (3) The combination of CT for anatomic detail followed by ultrasonography for triplanar guidance provides the easiest and safest method for diagnosis, localization, and drainage in most cases.

SPIRA,

AND

ROBBINS

(4) Transperitoneal drainage routes may be safely used for intraperitoneal abscesses when CT or a combination of ultrasound and barium studies provides the anatomic detail necessary to avoid loops of bowel. (5) The majority of intraabdominal abscesses are amendable to percutaneous drainage techniques because they are both unilocular and have a safe percutaneous access route. (6) The procedure can be performed in most radiology departments with sectional imaging because the technique is relatively simple and the materials are readily available. In conclusion, we feel that this methodology fulfills the criteria of Ochsner and DeBakey for “the ideal type of drainage procedure . . . characterized by directness, simplicity, and above all avoidance of unnecessary contamination of uninvolved areas.“” Thus, when sectional imaging demonstrates a unilocular abscess cavity with a safe percutaneous route, a trial of percutaneous drainage should be considered as a method of definitive treatment. Only if it fails should surgery be performed. Open drainage is always available for the surgeon if he feels that the clinical situation warrants operative intervention.

REFERENCES I. Doust BD, Quiroz F, Stewart JM: Ultrasonic distinction of abscesses from other intra-abdominal fluid collections. Radiology 1977; 125:213-8 2. Gerzof SG: The role of ultrasound in the search for intra-abdominal and retropcritoneal abscesses. In: Taylor K, ed. Clinics in Diagnostic Ultrasound. New York, Churchill Livingstone (in press) 3. Doust BD, Thompson R: Ultrasonography of abdominal fluid collections. Gastrointest Radio1 1978; 3:273-9 4. Gerzof SG, Robbins AH, Birkett DH: Computed tomography in the diagnosis and management of abdominal abscesses. Gastrointest Radio1 1978; 3:387-94 5. Haaga JR, Alfidi RJ, Havrilla TR, et al: CT detection and aspiration of abdominal abscess. Am J Roentgen01 1977; I28:465-74 6. Koehler PR, Moss AA: Diagnosis of intra-abdominal and pelvic abscesses by computerized tomography. JAMA 1980; 244149952 7. Gerzof SG, Robbins AH, Birkett DH, et al: Percutaneous catheter drainage of abdominal abscesses guided by ultrasound and computed tomography. Am J Roentgen01 1979; 133:1-8 8. Gerzof SG, Robbins AH, Pugatch RD, et al: New applications of old radiographic techniques applied to computed tomography. Comput Tomogr 1977; I:33 l-8

9. Maklad NF, Doust MB, Baum JK: Ultrasonic diagnosis of postoperative intra-abdominal abscess. Radiology 1974; 113:417-2 10. Kressel NY, Filly RA: Ultrasonographic appearance of gas-containing abscesses in the abdomen, Am J Roentgenol 1978; 130:71-3 1 I. Smith EH, Bartrum RJ Jr: Ultrasonically guided percutaneous aspiration of abscesses. Am J Roentgenol 1974; 122:308-l 2 12. Altemeier WA, Culberston WR, Fullen WD, et al: Intra-abdominal abscesses. Am J Surg 1973; 125:70-9 13. Ochsner A, Graves AM: Subphrenic abscess, an analysis of 3372 collected and personal cases. Ann Surg 1933; 98:961-90 14. Robbins AH, Pugatch RD, Gerzof SG, et al: Further observations on the medical efficacy of computed tomography of the chest and abdomen. Radiology (in press) 15. Nagler SM. Poticha SM: Intra-abdominal abscess in regional enteritis. Am J Surg 1979; 137:35&I 16. Ochsner retroperitoneal 1964; 21:156

A: Reminiscence: The development of the operation of subphrenic abscess. Rev Surg

17. Callender CL. Surgical anatomy. Saunders, 1941:317, 345-9, 401

Philadelphia:

WB

PERCUTANEOUS

ABSCESS

DRAINAGE

18. Fitzgerald P. Appendix abscess. In: Rob C, Smith R, eds. Operative Surgery (ed 2). Philadelphia, JB Lippincott, 1968:484 19. Holm HH, Rasmussen SN, Kristensen JK: Ultrasonically guided percutaneous puncture technique. J Clin Ultrasound 1973; 1:27-31 20. Anderson CB, Marr JJ, Ballinger WF: Anerobic infections in surgery: Clinical review. Surgery 1976; 79:3 1324 21. Pedersen JF: Renal antibiotic therapy governed by ultrasound guided aspirations, J Urol 1973; 109:777-8 22. Gronvall J, Gronvall S, Hegedus V: Ultrasound

71

guided drainage of fluid-containing masses usmg angiographic catheterization techniques. Am J Roentgen01 1977; 129:997-1002 23. Ingram JM: Suprapubic cystotomy by trocar catheter: A preliminary report. Am J Obstet Gynecol 1972; I13:1108-I3 24. Ingram JM: Further experience with suprapubic drainage by trocar catheter. Am J Obstct Gynecol 1975; 121:885-91 25. Ochsner A, DeBakey M: Subphrenic abscess: A collective review and an analysis of 3608 collected and personal cases. Int Abstr Surg 1938; 66:426-3X