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Nonvascular Pediatric Interventional Radiology
Canadian Association of Radiologists Journal 63 (2012) S49eS58 www.carjonline.org
Vascular and Interventional Radiology / Radiologie vasculaire et radiologie d’intervention
Nonvascular Pediatric Interventional Radiology Joshua Burrill, MBBSa,b, Manraj K. S. Heran, MDb,c,* a Department of Radiology, St Paul’s Hospital, Vancouver, British Columbia, Canada Department of Radiology, BC Children’s Hospital, Vancouver, British Columbia, Canada c Department of Radiology, Vancouver General Hospital, Vancouver, British Columbia, Canada b
Abstract Interventional radiology procedures are increasingly in demand in both the adult and pediatric populations. Pediatric procedures mirror many of the adult procedures but with increased complexity due to considerations related to patient size and the requirements for sedation and radiation protection. This article reviews the various nonvascular pediatric interventional procedures and provides information on sedation and radiation protection. The aim is to provide a greater exposure to the possible treatment options for pediatric patients and to facilitate understanding of imaging after various interventions. Resume La demande de procedures de radiologie d’intervention ne cesse de cro^ıtre chez les patients adultes et pediatriques. Les actes pediatriques sont analogues a ceux pratiques chez les adultes, mais ils presentent une complexite accrue en raison de facteurs lies a la taille du patient et aux modalites de sedation et de radioprotection. L’article passe en revue les diverses procedures en radiopediatrie d’intervention non vasculaire et fournit de l’information sur la sedation et la radioprotection. Il vise a mieux faire conna^ıtre les choix de traitement possibles des patients pediatriques et a faciliter l’interpretation de l’imagerie apres plusieurs interventions. Ó 2012 Canadian Association of Radiologists. All rights reserved. Key Words: Pediatric radiology; Interventional radiology; Nonvascular interventional radiology; Pediatric interventional radiology
Interventional radiology (IR) is an essential hospital specialty that provides an independent diagnostic and treatment modality as well as an adjunct to medical and surgical therapies. The need for pediatric IR is increasing, with the scope of pediatric intervention that ranges from common procedures, such as vascular access and abscess drainage, through to complex and potentially rare procedures, such as vein of Galen embolization. This review will cover the various nonvascular pediatric IR (PIR) procedures performed in a specialist pediatric centre. Sedation Although some PIR procedures can be done without sedation or anesthetic support, the majority of PIR requires some degree of sedation, ranging from mild sedation to general anesthetic with intubation. The increased risks
associated with pediatric sedation are well known [1]. Although there are practices in which the radiology department provides a range of sedation support to their PIR patients, in our institution, there is a multidisciplinary approach to each procedure, with sedation being supervised by an anesthesiologist. Anesthetic or sedation care is tailored to each patient, based on the duration and type of procedure. The anesthesiologist not only determines the level of sedation but all aspects of associated patient care, including hydration, temperature, oxygenation, and cardiovascular status, all of which are important in pediatric patients, especially during more-complex, time-consuming procedures. When possible, we also combine multiple procedures in one sitting to avoid the risks and patient stress related to multiple episodes of sedation. Coagulopathy
Disclosures: The authors have no conflicts of interest to disclose. * Address for correspondence: Manraj Kanwal Singh Heran, MD, Department of Radiology, British Columbia’s Children’s Hospital, 4480 Oak Street, Vancouver, BC V6H 3V4, Canada. E-mail address: [email protected] (M. K. S. Heran).
The Society of Interventional Radiology (SIR) has published guidelines for the management of coagulation status and hemostasis risk [2]. These guidelines are nonspecific
0846-5371/$ - see front matter Ó 2012 Canadian Association of Radiologists. All rights reserved. doi:10.1016/j.carj.2011.08.003
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regarding the population with which they deal; however, the literature these guidelines refer to includes adult and pediatric studies. Procedures are categorized into low, moderate, and significant risk, with preprocedure laboratory tests and management strategies for each category. Radiation Protection Exposure to ionizing radiation during PIR procedures is an area of concern, with a higher estimated risk of cancer than with adults [3]. This concern has been increasingly recognized in recent years, with an emphasis on reducing pediatric exposure by using such dose-reduction tools as those provided by the Image Gently campaign [4]. Technological advances have allowed for a range of dose-reduction features, including pulse fluoroscopy, last image-hold, contrast overlay, and pediatric-specific dose settings that lower the kV and mA. Imaging modalities that do not use ionizing radiation, such as ultrasound, should be used when possible but not to the detriment of patient safety. Magnetic resonance imaging (MRI) also is being considered for use during PIR procedures; however, considerable limitations exist in allowing this to become a practical tool outside the research setting. During angiography, the patient dose can be reduced by using patient shielding, removing the grid for infants, reducing the air gap between the image receptor and patient, and optimizing the source-to-skin distance [5]. Drainage Image-guided drainage of collections is performed for both diagnostic and therapeutic reasons (Figure 1). Appendicitis-related abscesses are the most common intraabdominal abscesses in the pediatric population [6]. Diagnostic taps can be performed to characterize collections and, in cases of possible infection, confirm the diagnosis before therapeutic drainage. In patients with massive ascites, paracentesis can be performed to relieve mass-related symptoms. Ideally, all drainage procedures would be performed by using the Seldinger technique and ultrasound guidance. However, adequate visualization of the collection and overlying or adjacent structures is essential, and may require the use of either fluoroscopic or computed tomography (CT) guidance, such as in the case of deep intra-abdominal collections in teenage patients. A combined fluoroscopic and ultrasound approach can be used to avoid CT. The collection is cannulated with a 22-gauge needle and a guidewire is inserted. A Tuohy Borst adapter is placed on the hub of the needle, which then can be pulled back over the guidewire while injecting contrast to ensure that bowel has not been traversed. Perirectal or deep pelvic abscesses may sometimes be best drained via a transrectal approach, by using either transrectal or transabdominal ultrasound to visualize the procedure. The size of the drainage catheter placed depends on the nature of the collection. Catheters, 5F-8F, are usually sufficient for simple fluid-type collections, whereas larger drains (12F-14F) may be required for more complex collections.
Pleural Effusions and Empyema The drainage of pleural effusions and empyema is typically performed by using the Seldinger technique under ultrasound guidance. Intrapleural fibrinolytics, such as tissue plasminogen activator, are recommended when the collection is multiloculated, which increases the success of drainage [7]. Chest drains can be removed if there is no significant residual effusion and the drain output is <25 mL/day. Biopsy In the case of complex masses and uncertain pathology, attendance by a pathologist or trained pathology technician can ensure that an adequate tissue sample is obtained, thereby reducing the risk of a second procedure. Coaxial guide needles can act as conduits for multiple biopsies and allow the biopsy tract to then be embolized with Gelfoam. Careful intraprocedural imaging and review of any prior imaging before the procedure ensures that the optimum tract is used with appropriate targeting of the aspects of the lesion to be biopsied (such as obtaining samples of viable tumour while avoiding areas of necrosis). Hepatic Pediatric liver biopsies are performed for a variety of indications, including investigation of abnormal liver function tests, confirmation of biliary atresia, assessment for nonalcoholic steatohepatitis, and staging viral hepatitis, and for metallic element analysis. Although uncommon, biopsies also may be requested of intrahepatic mass lesions, such as suspected primary or secondary neoplasms. The North American Society for Pediatric Gastroenterology and Nutrition have published a position statement on outpatient percutaneous liver biopsies due to the increased risk for hemorrhagic shock in pediatric patients [8]. They recommend that the procedure be performed by an experienced physician, with adequate observation after the procedure and before discharge. They also recommend that patients limit their activities after the procedure and be within 30 minutes from the facility where the biopsy was performed for 24 hours after biopsy. The latter recommendation is of particular relevance to Canadian institutions where the patient may reside a significant distance away from the facility. In such circumstances, patients may be admitted overnight for optimal observation. These procedures are best done by using ultrasound visualization. Minor complications can be seen in 0.7%-11.7% of patients, with major complications in 0.7%-6.4% [9]. Although there are many approaches to performing hepatic biopsies, in our institution, we prefer to perform ultrasoundguided 18-gauge core biopsies by using an epigastric approach. We find the procedure easier to perform, and direct compression can be applied to the area after biopsy, potentially aiding in hemostasis. For biopsies of focal liver masses, we typically use a coaxial technique with consideration given to embolization of the tract at the end of the procedure, by using either Gelfoam pledgets or a thick Gelfoam slurry.
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Figure 1. Abscess drainage. A 15-year-old male patient with Crohn disease presenting with right lower quadrant pain and fever. (A, B) Axial T2 fat-saturation magnetic resonance imaging and coronal reconstruction, showing a right iliac fossa abscess (arrow) with a sinus tract to the cecum (arrow heads). (C) The abscess was cannulated under ultrasound and fluoroscopic guidance, and contrast was injected to confirm filling of the abscess (white arrows), followed by placement of a guidewire (black arrow). (D) A pigtail catheter was then inserted over the guidewire as seen on subsequent imaging.
Transjugular liver biopsies may be necessary in the pediatric population when there is an increased risk of bleeding from a percutaneous biopsy due to coagulopathy or the presence of a large amount of ascites [10]. This procedure may be technically challenging in small children due to patient size; however, the concurrent use of transabdominal ultrasound can be useful in obtaining adequate samples while minimizing procedural complications, such as the risk of transcapsular pass (Figure 2). Renal Renal biopsy is almost always performed by using ultrasound guidance and is done to establish a tissue diagnosis or to assess the histopathologic response to treatment. Transplant kidneys are usually biopsied with the patient lying supine because they are most often placed in the iliac fossae. Native kidneys are typically biopsied with the patient lying prone, although the procedure can be done with the patient in a lateral position [11]. Usually, two 18-gauge core biopsies are sufficient for diagnosis. However, in our institution, we have a renal pathology technician present at the time of the
procedure to confirm adequate tissue samples. Major complications, including hemorrhage, have been reported in 1.5%-3.4% of children, although this rarely requires active management, such as transarterial embolization [11]. Nephrostomy and Other Genitourinary Intervention Percutaneous cannulation of the renal tract is a high-risk procedure for hemorrhage, and, therefore, it is essential to correct any coagulopathy. Antibiotic prophylaxis is highly recommended [11]. Nephrostomy The indications for pediatric nephrostomy are similar to those in the adult setting. The most common indication is an obstructed (potentially infected) renal collecting system due to various causes, including urolithiasis, hematoma, mycetoma, anatomical pelviureteric or vesicoureteric junction obstruction, or extrinsic masses [11]. The patient is positioned prone or semiprone. Because a nephrostomy procedure is more painful than a renal biopsy, adequate sedation is
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using intravenous urography to delineate the calyceal anatomy [11]. Communication with the urologist is essential before obtaining access for percutaneous nephrolithotomy to ensure that the site of access simplifies the process of stone removal, thereby reducing the length of the urologic procedure and the need for repeated intervention. Stone-free rates after a single session range from 86.9%- 98.5% [13]. Access is obtained with the patient lying prone or semiprone. The nephrostomy can be performed by direct puncture directed at the calculus, or of a dilated calyx obstructed by the calculus (Figure 3). When there is a significant stone burden that involves multiple lower pole calyces, a superior calyceal puncture may aid in avoiding multiple percutaneous nephrolithotomies [16].
Figure 2. Transjugular liver biopsy. A 2-year-old boy with a coagulopathy that required a liver biopsy. The armored sheath was placed into the right hepatic vein (white arrows) with both fluoroscopic and ultrasound imaging. The ultrasound (black arrowheads) enabled a safe biopsy to be performed without traversing the liver capsule with the biopsy needle (black arrow).
essential. Visualization and access is typically easier in the pediatric population due to patient size and less subcutaneous fat. However, careful periprocedural ultrasound is needed to identify the ideal calyx to access and to avoid bowel. Various access needles can be used. Micropuncture sets are often used, especially when there is minimal pelvicaliceal dilatation. However, in neonates and infants, micropuncture technique may have reduced success due to the thin renal parenchyma being indented but not traversed by the 5F dilator, which can result in malpositioning of the nephrostomy tube [12]. Percutaneous nephrostomies can provide access for ureteric intervention. As in adults, ureteric obstruction can be treated with internal-external nephrostomies or double-J ureteric stents. Anastomotic ureteric strictures related to renal transplantation can be treated with balloon dilation followed by insertion of a ureteric stent. Percutaneous Nephrolithotomy Pediatric patients account for approximately 1%-3% of all patients with urolithiasis [13,14]. They are at high risk for recurrence, and a significant number of the patients have a metabolic predisposition [14]. Imaging is essential for treatment planning, with ultrasound being the imaging modality of choice. However, there are differences of opinion as to whether CT is helpful. Some researchers think that CT optimizes treatment and access planning, and can identify those patients with a retrorenal colon, which has a reported incidence of 1%-14% [15]. Other researchers recommend
Figure 3. Percutaneous nephrolithotomy. A 19-month-old girl with sacral agenesis, cloacal malformation, and solitary left kidney, with a staghorn calculus. (A) Volume rendered coronal image from a noncontrast computed tomography, showing the large left staghorn calculus (arrows). (B) A fluoroscopic image of dual percutaneous guidewires down the left ureter (white arrows), with a 14F peel-away sheath left as an access conduit for stone removal (black arrows).
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Endoluminal and Percutaneous Gastrointestinal Intervention Treatment of Esophageal Strictures There are multiple causes of esophageal strictures in the pediatric patient. In our institution, as elsewhere, the most common cause that requires intervention is a postsurgical stricture related to esophageal atresia repair [7]. Other causes include achalasia, eosinophilic esophagitis, strictures related to fundoplication, and ingestion of corrosives (Figure 4). Fluoroscopic-guided balloon dilation of the esophageal stricture is our treatment of choice. Esophageal dilation is typically performed with the patient under general anesthetic with patient intubation by using a cuffed endotracheal tube for airway protection, thereby reducing the risk of aspiration. After a diagnostic contrast esophagram is performed, balloon dilation is performed over a guidewire. The balloon size depends on patient size, the cause and degree of stricture, and previous intervention. The aim of the procedure is to adequately dilate the esophagus without causing perforation, a complication that occurs in fewer than 1% of cases and more commonly in strictures related to corrosive ingestion than surgery [17,18]. For very high-grade strictures, to minimize the risk of esophageal perforation and possible mediastinitis, is best to consider serial dilation over more than one session rather than attempting to achieve complete relief of the stricture at one sitting. Success is confirmed by relief of symptoms, and the procedure can be repeated if symptoms recur. Although the risk of perforation is rare, there is
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controversy as to the need for a postprocedure esophagram as well as the necessity of the child remaining nil by mouth for a period of time [18]. In our institution, we keep the patient nil by mouth for 1 hour, then sips of clear fluids for 24 hours, then full fluids for a further 24 hours before commencing a normal diet as tolerated. The use of concomitant acid blockers is important because many strictures are aggravated by reflux. Indications for esophageal stents in the pediatric population are not well-defined but include recurrent severe strictures after balloon dilation, often due to surgery or corrosive ingestion (Figure 4), and esophageal leaks [19]. Various, usually removable, esophageal stents have been used in children, including modified tracheobronchial stents [20], silicon stents [21], and biodegradable stents [22], with good results. These ideally should be removed no later than 4-6 weeks to reduce the risk of mucosal adhesion and ingrowth [19]. Large and Small Bowel Balloon Dilation Small bowel and colonic strictures also can be treated with balloon dilation [23,24]. Stable access of the duodenum can be difficult when using a peroral approach due to overdilation of the stomach and fundal looping of guidewires (Figure 5). If a gastrostomy is available, it greatly simplifies stable access to the stricture [17]. Gastrostomy Gastrostomy (G)-tube insertion can be done for patients who are unable to ingest enough oral nutrition but who have
Figure 4. Caustic esophageal stricture. A 4-year-old girl who swallowed bleach. (A) Esophagram, showing local focal stricture (black arrows), with 2 focal perforations leaking into the right pleural space (white arrows). (B) Snare retrieval (white arrow) of an orally placed guidewire (black arrow) via a previously placed gastrostomy. (C) This procedure enabled stable access for the deployment of 2 covered self-expanding esophageal stents with no subsequent leak (arrows).
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Figure 5. Duodenal stricture dilation. A 15-year-old patient with chronic inflammatory disease of the antrum and proximal duodenum, which resulted in a tight stricture. (A) A stricture identified on T2-weighted coronal magnetic resonance imaging (arrow). (B) The stricture was crossed (arrow) by using fluoroscopy. (C, D) The stricture (arrow) was dilated with a 12-mm balloon.
adequate bowel for absorption, including neurologically impaired children and those patients with structural or functional esophageal abnormalities, high metabolic needs, or severe illness [25]. The procedure can be performed endoscopically, surgically, or laparoscopically, or by using image guidance. Image-guided G-tube insertion is performed by using a combination of ultrasound and fluoroscopic guidance, with either an antegrade or retrograde technique [25]. The procedure can be performed with the patient under sedation. The ideal puncture position for the G tube is lateral to the rectus muscle and approximately 2 cm below the costal margin, which allows for patient growth. We use the retrograde technique in our institution. This involves percutaneous puncture of the gas-insufflated stomach followed by insertion of 2 Cope pediatric retention sutures (Cook Medical, Bloomington, IN), which are used to bring the gastric wall and abdominal wall in direct contact and reduce the risk of an intraperitoneal gastric leak. A G tube can then be inserted over a guidewire. Both the nasogastric tube and the G tube should be left on free drainage overnight before starting a slow build up to full feeds. The stay sutures can be cut at the skin after 2 weeks. The antegrade approach uses a G tube with a fixed disk on one end, which avoids the need for stay sutures. There are cases of bowel obstruction due to these disks, which caused abscess formation and perforation [26].
Minor pneumoperitoneum is a common adverse effect of the procedure and can be aspirated by using a 27-gauge needle if there is significant pneumoperitoneum [25]. The most serious complication is peritonitis, which occurs in approximately 3% of cases [25,27]. G tubes need to be left for about 6 weeks to allow for a well-healed tract, which reduces the risk of separation of the gastric and anterior abdominal walls. After 6 weeks, the small-bore (typically 5F-8F) pigtail catheter can be upsized to a Mic-Key lowprofile G tube (Kimberley-Clark, Dallas, TX) which is both easier to use and esthetically more pleasing than a pigtail catheter. Gastrojejunostomy Insertion Transgastric jejunostomy tubes may be needed in some patients to reduce the incidence of significant reflux. A gastrojejunostomy (GJ) tube can either be a single lumen tube or a dual lumen tube with a gastric port. These tubes can be placed at the time of the initial gastrostomy or later, as required (Figure 6). Various GJ tubes are available, some that require adjustment of the jejunal component length. Jejunostomy tubes also can be placed through existing gastrostomy tubes for ease of placement and to reduce the risk of gastroperitoneal dehiscence, which is particularly useful for surgically placed gastrostomies because a 5F GJ tube
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Figure 6. Gastrojejunostomy insertion. Retrograde insertion of gastrojejunostomy tube. (A) Percutaneous puncture of the gastric bubble (arrow) with both nasojejunal and nasogastric tubes in situ. (B) The stay-sutures (white arrow) are inserted, followed by a hockey stick catheter (black arrow), which is passed into the jejunum and exchanged over a guidewire for the gastrojejunostomy tube.
fits snugly into an externally cut 12F gastrostomy tube. Of note, jejunostomy tubes can cause intussusception and perforation [25]. Percutaneous Cecostomy Cecostomy is a treatment for fecal incontinence, by providing an access port for regular antegrade enemas. The pediatric causes of fecal incontinence include spinal dysraphism, Hirschsprung disease, chronic constipation, other structural or functional anorectal abnormalities, and neurogenic bowel [26]. In these patients, overflow incontinence occurs and regular enemas can reduce the incidence of this debilitating condition. Percutaneous cecostomy is a relatively simple procedure first advocated by Shandling et al [28]. Percutaneous puncture is performed to place 1 or 2 Cope stay sutures (Cook Medical), followed by another puncture for insertion of a guidewire and, after tract dilation, an 8.5F pigtail cecostomy tube. After 6 weeks, this pigtail catheter usually is replaced with a Chait Trapdoor cecostomy tube (Cook Medical) due to its low profile and unobtrusive appearance (Figure 7). Percutaneous cecostomy in pediatric patients is a very successful procedure, particularly for those with neurogenic fecal incontinence, and is a low-risk procedure, with minimal complications [29,30].
commonly performed by using a Roux-en-Y, and ERCP is then not possible. In these cases, biliary obstruction can be investigated and treated by using percutaneous transhepatic cholangiography (PTC) [31]. The PTC success rate, even of nondilated systems, is higher than 90%, with an approximately 11% minor complication rate [32]. In neonates with cholestatic jaundice, there are multiple possible causes, including biliary atresia. Percutaneous cholecystocholangiography is an alternative to laparoscopic cholangiography in cases of cholestatic jaundice in which the
Hepatobiliary Intervention The majority of pediatric biliary interventions are performed on liver transplantation recipients, and, therefore, cases are concentrated in transplantation centres [31]. Another common indication is the evaluation of neonatal cholestasis. The risk of sepsis, although less than 1%, is serious. Therefore, appropriate antibiotic prophylaxis is essential [32]. Biliary investigation of nontransplanted livers is usually performed by endoscopic retrograde cholangiopancreatography (ERCP). Liver transplantations are
Figure 7. Chait cecostomy. Tubogram through the Chait tube, confirming its correct location within the cecum.
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Figure 8. Cholecystocholangiogram. An 8-week-old neonate with jaundice that was concerning for biliary atresia. (A) An ultrasound, demonstrating the presence of a collapsed gallbladder (arrows). (B) Percutaneous cholecystocholangiogram via cannulation of the gallbladder (black arrow), demonstrating a normal cystic duct (white arrowhead), normal common bile duct (white arrows), and attenuated intrahepatic bile ducts (black arrowheads), thereby excluding the diagnosis of biliary atresia.
gallbladder can be identified on ultrasound [33,34]. This occurs in types 1 and 3 of biliary atresia, which represent approximately 22% of biliary atresia cases. The procedure involves percutaneous cannulation of the gallbladder by using a 22- to 27-gauge needle. Contrast is then injected to identify any abnormality with the biliary tree (Figure 8). Due to the needle size, there is minimal risk, and there should be no significant complications [33,34]. Other Gastrointestinal Interventions Salivary Glands Sialorrhea or drooling is normal in children younger than 4 years of age. In children older than this, it is abnormal and may be due to a neurologic disorder, for example, cerebral palsy [35]. Approximately 90% of saliva is produced by the
submandibular and parotid glands. Ultrasound-guided injection of botulinum toxin A into the parotid and submandibular glands has been used successfully to reduce the amount of drooling. The procedure is effective in about 70% of patients and has a average duration of between 2 and 4.6 months [35]. Minor complications, such as dry mouth, are common. The most concerning major complications are difficulties swallowing, which results in aspiration pneumonia, or inadvertent injection of the facial nerve, which results in reversible facial nerve palsy. Botulinum toxin also is injected into the muscles around the hip joint as a treatment for hip pain in patients with cerebral palsy and hip spasm [36]. Salivary duct stenosis is uncommon in children, with the most common cause of obstructive sialadenitis being debris and/or calculi [37,38]. Fluoroscopic-guided balloon dilation has been used as a successful treatment for duct stenosis when it does occur [17,37].
Figure 9. Stent insertion for tracheal stenosis. A 23-month-old patient with tracheomalacia and stenosis, resulting from aberrant left pulmonary artery (‘‘pulmonary sling’’). (A) A tracheogram, showing stenoses of the trachea and left and right main bronchi (arrows) after attempted surgical reconstruction. (B) Stent reconstruction of the distal trachea and the right and left mainstem bronchi, with resultant wide patency.
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Other Pediatric Interventions Tracheobronchial Intervention Tracheobronchial intervention for pediatric airway obstruction and stenosis is a complex entity that requires the involvement of a multidisciplinary team. This has been reviewed in greater detail elsewhere [7,39,40]. Balloon dilation and stenting have been used to treat tracheomalacia, bronchomalacia, tracheal obstruction, and postoperative tracheal stenosis (Figure 9). Many questions remain regarding the indication for stenting, the type of stent to use, and the durability and/or long-term complication profile of these stents. Musculoskeletal Intervention Musculoskeletal intervention in pediatric patients mirrors those in adults, including bone biopsies, spinal pain procedures (eg, nerve root blocks), joint injections, and radiofrequency ablation of osteoid osteomas [26]. Conclusion The majority of the procedures covered in this article are also performed on the adult population. Most physicians are aware that the concept that the ‘‘pediatric patient is a small adult’’ is wrong. When dealing with an adolescent, the majority of IR procedures are identical in technique to those performed on adults. However, for younger children, a wide variety of techniques and equipment is needed to cope with variations in body size and physiology. As more PIR procedures are performed, a greater awareness of the different techniques can guide those in a general radiology department. This awareness, combined with the introduction of adult complex interventional procedures to the pediatric population, reinforces the nonmedical truism that, when PIR is concerned, ‘‘adults are just big kids.’’ References [1] Cravero JP, Beach ML, Blike GT, et al. The incidence and nature of adverse events during pediatric sedation/anesthesia with propofol for procedures outside the operating room: a report from the Pediatric Sedation Research Consortium. Anesth Analg 2009;108:795e804. [2] Malloy PC, Grassi CJ, Kundu S, et al. Consensus guidelines for periprocedural management of coagulation status and hemostasis risk in percutaneous image-guided interventions. J Vasc Interv Radiol 2009; 20(Suppl):S240e9. [3] Brenner D, Elliston C, Hall E, et al. Estimated risks of radiationinduced fatal cancer from pediatric CT. AJR Am J Roentgenol 2001; 176:289e96. [4] Alliance for Radiation Safety in Pediatric Imaging. Steps for radiation safety in pediatric interventional radiology. Available at: http://spr. affiniscape.com/associations/5364/ig/index.cfm?page¼603. Accessed December 13, 2011. [5] Heran MK, Marshalleck F, Temple M, et al. Joint quality improvement guidelines for pediatric arterial access and arteriography: from the Societies of Interventional Radiology and Pediatric Radiology. J Vasc Interv Radiol 2010;21:32e43. [6] Hogan MJ, Hoffer FA. Biopsy and drainage techniques in children. Tech Vasc Interv Radiol 2010;13:206e13.
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[7] Roebuck DJ, Hogan MJ, Connolly B, et al. Interventions in the chest in children. Tech Vasc Interv Radiol 2011;14:8e15. [8] Fox VL, Cohen MB, Whitington PF, et al. Outpatient liver biopsy in children: a medical position statement of the North American Society for Pediatric Gastroenterology and Nutrition. J Pediatr Gastroenterol Nutr 1996;23:213e6. [9] Harwood J, Bishop P, Liu H, et al. Safety of blind percutaneous liver biopsy in obese children: a retrospective analysis. J Clin Gastroenterol 2010;44:e253e5. [10] Kaye R, Sane SS, Towbin RB. Pediatric intervention: an updatedpart II. J Vasc Interv Radiol 2000;1:807e22. [11] Barnacle AM, Roebuck DJ, Racadio JM. Nephro-urology interventions in children. Tech Vasc Interv Radiol 2010;13:229e37. [12] Koral K, Saker MC, Morello FP, et al. Conventional versus modified technique for percutaneous nephrostomy in newborns and young infants. J Vasc Interv Radiol 2003;14:113e6. [13] Straub M, Gschwend J, Zorn C. Pediatric urolithiasis: the current surgical management. Pediatr Nephrol 2010;25:1239e44. [14] Hiorns MP. Imaging of urinary tract lithiasis: who, when and how? Pediatr Radiol 2008;38(Suppl 3):S497e500. [15] Chan R, Li DK. An extreme case of retrorenal colon. AJR Am J Roentgenol 2006;187:W438. [16] Anand A, Kumar R, Dogra PN, et al. Safety and efficacy of a superior caliceal puncture in pediatric percutaneous nephrolithotomy. J Endourol 2010;24:1725e8. [17] Roebuck DJ, McLaren CA. Gastrointestinal intervention in children. Pediatr Radiol 2011;41:27e41. [18] Antoniou D, Soutis M, Christopoulos-Geroulanos G. Anastomotic strictures following esophageal atresia repair: a 20-year experience with endoscopic balloon dilatation. J Pediatr Gastroenterol Nutr 2010; 51:464e7. [19] Kramer RE, Quiros JA. Esophageal stents for severe strictures in young children: experience, benefits, and risk. Curr Gastroenterol Rep 2010; 12:203e10. [20] Best C, Sudel B, Foker JE, et al. Esophageal stenting in children: indications, application, effectiveness, and complications. Gastrointest Endosc 2009;70:1248e53. [21] Foschia F, De Angelis P, Torroni F, et al. Custom dynamic stent for esophageal strictures in children. J Pediatr Surg 2011;46:848e53. [22] Vandenplas Y, Hauser B, Devreker T, et al. A biodegradable esophageal stent in the treatment of a corrosive esophageal stenosis in a child. J Pediatr Gastroenterol Nutr 2009;49:254e7. [23] Diamond IR, Hayes-Jordan A, Chait P, et al. A novel treatment of congenital duodenal stenosis: image-guided treatment of congenital and acquired bowel strictures in children. J Laparoendosc Adv Surg Tech A 2006;16:317e20. [24] van Rijn RR, van Lienden KP, Fortuna TL, et al. Membranous duodenal stenosis: initial experience with balloon dilatation in four children. Eur J Radiol 2006;59:29e32. [25] Connolly B, Krishnamurthy G, Amaral J. Upper gastrointestinal access in children: techniques and outcomes. Tech Vasc Interv Radiol 2010; 13:222e8. [26] Kaye RD, Sane SS, Towbin RB. Pediatric intervention: an updatedpart I. J Vasc Interv Radiol 2000;11:683e97. [27] Lewis EC, Connolly B, Temple M, et al. Growth outcomes and complications after radiologic gastrostomy in 120 children. Pediatr Radiol 2008;38:963e70. [28] Shandling B, Chait PG, Richards HF. Percutaneous cecostomy: a new technique in the management of fecal incontinence. J Pediatr Surg 1996;31:534e7. [29] Chait PG, Shandling B, Richards HM, et al. Fecal incontinence in children: treatment with percutaneous cecostomy tube placementda prospective study. Radiology 1997;203:621e4. [30] Donkol RH, Al-Nammi A. Percutaneous cecostomy in the management of organic fecal incontinence in children. World J Radiol 2010;2: 463e7. [31] Racadio JM, Kukreja K. Pediatric biliary interventions. Tech Vasc Interv Radiol 2010;13:244e9.
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[32] Lorenz JM, Funaki B, Leef JA, et al. Percutaneous transhepatic cholangiography and biliary drainage in pediatric liver transplant patients. AJR Am J Roentgenol 2001;176:761e5. [33] Meyers RL, Book LS, O’Gorman MA, et al. Percutaneous cholecystocholangiography in the diagnosis of obstructive jaundice in infants. J Pediatr Surg 2004;39:16e8. [34] Nwomeh BC, Caniano DA, Hogan M. Definitive exclusion of biliary atresia in infants with cholestatic jaundice: the role of percutaneous cholecysto-cholangiography. Pediatr Surg Int 2007;23: 845e9. [35] Khan WU, Campisi P, Nadarajah S, et al. Botulinum toxin A for treatment of sialorrhea in children: an effective, minimally invasive approach. Arch Otolaryngol Head Neck Surg 2011;137: 339e44.
[36] Lundy CT, Doherty GM, Fairhurst CB. Botulinum toxin type A injections can be an effective treatment for pain in children with hip spasms and cerebral palsy. Dev Med Child Neurol 2009;51: 705e10. [37] Faure F, Querin S, Dulguerov P, et al. Pediatric salivary gland obstructive swelling: sialendoscopic approach. Laryngoscope 2007; 117:1364e7. [38] Jabbour N, Tibesar R, Lander T, et al. Sialendoscopy in children. Int J Pediatr Otorhinolaryngol 2010;74:347e50. [39] Jacobs JP, Quintessenza JA, Botero LM, et al. The role of airway stents in the management of pediatric tracheal, carinal, and bronchial disease. Eur J Cardiothorac Surg 2000;18:505e12. [40] McLaren CA, Elliott MJ, Roebuck DJ. Tracheobronchial intervention in children. Eur J Radiol 2005;53:22e34.
Vascular and Interventional Radiology / Radiologie vasculaire et radiologie d’intervention
Nonvascular Pediatric Interventional Radiology Joshua Burrill, MBBSa,b, Manraj K. S. Heran, MDb,c,* a Department of Radiology, St Paul’s Hospital, Vancouver, British Columbia, Canada Department of Radiology, BC Children’s Hospital, Vancouver, British Columbia, Canada c Department of Radiology, Vancouver General Hospital, Vancouver, British Columbia, Canada b
Abstract Interventional radiology procedures are increasingly in demand in both the adult and pediatric populations. Pediatric procedures mirror many of the adult procedures but with increased complexity due to considerations related to patient size and the requirements for sedation and radiation protection. This article reviews the various nonvascular pediatric interventional procedures and provides information on sedation and radiation protection. The aim is to provide a greater exposure to the possible treatment options for pediatric patients and to facilitate understanding of imaging after various interventions. Resume La demande de procedures de radiologie d’intervention ne cesse de cro^ıtre chez les patients adultes et pediatriques. Les actes pediatriques sont analogues a ceux pratiques chez les adultes, mais ils presentent une complexite accrue en raison de facteurs lies a la taille du patient et aux modalites de sedation et de radioprotection. L’article passe en revue les diverses procedures en radiopediatrie d’intervention non vasculaire et fournit de l’information sur la sedation et la radioprotection. Il vise a mieux faire conna^ıtre les choix de traitement possibles des patients pediatriques et a faciliter l’interpretation de l’imagerie apres plusieurs interventions. Ó 2012 Canadian Association of Radiologists. All rights reserved. Key Words: Pediatric radiology; Interventional radiology; Nonvascular interventional radiology; Pediatric interventional radiology
Interventional radiology (IR) is an essential hospital specialty that provides an independent diagnostic and treatment modality as well as an adjunct to medical and surgical therapies. The need for pediatric IR is increasing, with the scope of pediatric intervention that ranges from common procedures, such as vascular access and abscess drainage, through to complex and potentially rare procedures, such as vein of Galen embolization. This review will cover the various nonvascular pediatric IR (PIR) procedures performed in a specialist pediatric centre. Sedation Although some PIR procedures can be done without sedation or anesthetic support, the majority of PIR requires some degree of sedation, ranging from mild sedation to general anesthetic with intubation. The increased risks
associated with pediatric sedation are well known [1]. Although there are practices in which the radiology department provides a range of sedation support to their PIR patients, in our institution, there is a multidisciplinary approach to each procedure, with sedation being supervised by an anesthesiologist. Anesthetic or sedation care is tailored to each patient, based on the duration and type of procedure. The anesthesiologist not only determines the level of sedation but all aspects of associated patient care, including hydration, temperature, oxygenation, and cardiovascular status, all of which are important in pediatric patients, especially during more-complex, time-consuming procedures. When possible, we also combine multiple procedures in one sitting to avoid the risks and patient stress related to multiple episodes of sedation. Coagulopathy
Disclosures: The authors have no conflicts of interest to disclose. * Address for correspondence: Manraj Kanwal Singh Heran, MD, Department of Radiology, British Columbia’s Children’s Hospital, 4480 Oak Street, Vancouver, BC V6H 3V4, Canada. E-mail address: [email protected] (M. K. S. Heran).
The Society of Interventional Radiology (SIR) has published guidelines for the management of coagulation status and hemostasis risk [2]. These guidelines are nonspecific
0846-5371/$ - see front matter Ó 2012 Canadian Association of Radiologists. All rights reserved. doi:10.1016/j.carj.2011.08.003
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regarding the population with which they deal; however, the literature these guidelines refer to includes adult and pediatric studies. Procedures are categorized into low, moderate, and significant risk, with preprocedure laboratory tests and management strategies for each category. Radiation Protection Exposure to ionizing radiation during PIR procedures is an area of concern, with a higher estimated risk of cancer than with adults [3]. This concern has been increasingly recognized in recent years, with an emphasis on reducing pediatric exposure by using such dose-reduction tools as those provided by the Image Gently campaign [4]. Technological advances have allowed for a range of dose-reduction features, including pulse fluoroscopy, last image-hold, contrast overlay, and pediatric-specific dose settings that lower the kV and mA. Imaging modalities that do not use ionizing radiation, such as ultrasound, should be used when possible but not to the detriment of patient safety. Magnetic resonance imaging (MRI) also is being considered for use during PIR procedures; however, considerable limitations exist in allowing this to become a practical tool outside the research setting. During angiography, the patient dose can be reduced by using patient shielding, removing the grid for infants, reducing the air gap between the image receptor and patient, and optimizing the source-to-skin distance [5]. Drainage Image-guided drainage of collections is performed for both diagnostic and therapeutic reasons (Figure 1). Appendicitis-related abscesses are the most common intraabdominal abscesses in the pediatric population [6]. Diagnostic taps can be performed to characterize collections and, in cases of possible infection, confirm the diagnosis before therapeutic drainage. In patients with massive ascites, paracentesis can be performed to relieve mass-related symptoms. Ideally, all drainage procedures would be performed by using the Seldinger technique and ultrasound guidance. However, adequate visualization of the collection and overlying or adjacent structures is essential, and may require the use of either fluoroscopic or computed tomography (CT) guidance, such as in the case of deep intra-abdominal collections in teenage patients. A combined fluoroscopic and ultrasound approach can be used to avoid CT. The collection is cannulated with a 22-gauge needle and a guidewire is inserted. A Tuohy Borst adapter is placed on the hub of the needle, which then can be pulled back over the guidewire while injecting contrast to ensure that bowel has not been traversed. Perirectal or deep pelvic abscesses may sometimes be best drained via a transrectal approach, by using either transrectal or transabdominal ultrasound to visualize the procedure. The size of the drainage catheter placed depends on the nature of the collection. Catheters, 5F-8F, are usually sufficient for simple fluid-type collections, whereas larger drains (12F-14F) may be required for more complex collections.
Pleural Effusions and Empyema The drainage of pleural effusions and empyema is typically performed by using the Seldinger technique under ultrasound guidance. Intrapleural fibrinolytics, such as tissue plasminogen activator, are recommended when the collection is multiloculated, which increases the success of drainage [7]. Chest drains can be removed if there is no significant residual effusion and the drain output is <25 mL/day. Biopsy In the case of complex masses and uncertain pathology, attendance by a pathologist or trained pathology technician can ensure that an adequate tissue sample is obtained, thereby reducing the risk of a second procedure. Coaxial guide needles can act as conduits for multiple biopsies and allow the biopsy tract to then be embolized with Gelfoam. Careful intraprocedural imaging and review of any prior imaging before the procedure ensures that the optimum tract is used with appropriate targeting of the aspects of the lesion to be biopsied (such as obtaining samples of viable tumour while avoiding areas of necrosis). Hepatic Pediatric liver biopsies are performed for a variety of indications, including investigation of abnormal liver function tests, confirmation of biliary atresia, assessment for nonalcoholic steatohepatitis, and staging viral hepatitis, and for metallic element analysis. Although uncommon, biopsies also may be requested of intrahepatic mass lesions, such as suspected primary or secondary neoplasms. The North American Society for Pediatric Gastroenterology and Nutrition have published a position statement on outpatient percutaneous liver biopsies due to the increased risk for hemorrhagic shock in pediatric patients [8]. They recommend that the procedure be performed by an experienced physician, with adequate observation after the procedure and before discharge. They also recommend that patients limit their activities after the procedure and be within 30 minutes from the facility where the biopsy was performed for 24 hours after biopsy. The latter recommendation is of particular relevance to Canadian institutions where the patient may reside a significant distance away from the facility. In such circumstances, patients may be admitted overnight for optimal observation. These procedures are best done by using ultrasound visualization. Minor complications can be seen in 0.7%-11.7% of patients, with major complications in 0.7%-6.4% [9]. Although there are many approaches to performing hepatic biopsies, in our institution, we prefer to perform ultrasoundguided 18-gauge core biopsies by using an epigastric approach. We find the procedure easier to perform, and direct compression can be applied to the area after biopsy, potentially aiding in hemostasis. For biopsies of focal liver masses, we typically use a coaxial technique with consideration given to embolization of the tract at the end of the procedure, by using either Gelfoam pledgets or a thick Gelfoam slurry.
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Figure 1. Abscess drainage. A 15-year-old male patient with Crohn disease presenting with right lower quadrant pain and fever. (A, B) Axial T2 fat-saturation magnetic resonance imaging and coronal reconstruction, showing a right iliac fossa abscess (arrow) with a sinus tract to the cecum (arrow heads). (C) The abscess was cannulated under ultrasound and fluoroscopic guidance, and contrast was injected to confirm filling of the abscess (white arrows), followed by placement of a guidewire (black arrow). (D) A pigtail catheter was then inserted over the guidewire as seen on subsequent imaging.
Transjugular liver biopsies may be necessary in the pediatric population when there is an increased risk of bleeding from a percutaneous biopsy due to coagulopathy or the presence of a large amount of ascites [10]. This procedure may be technically challenging in small children due to patient size; however, the concurrent use of transabdominal ultrasound can be useful in obtaining adequate samples while minimizing procedural complications, such as the risk of transcapsular pass (Figure 2). Renal Renal biopsy is almost always performed by using ultrasound guidance and is done to establish a tissue diagnosis or to assess the histopathologic response to treatment. Transplant kidneys are usually biopsied with the patient lying supine because they are most often placed in the iliac fossae. Native kidneys are typically biopsied with the patient lying prone, although the procedure can be done with the patient in a lateral position [11]. Usually, two 18-gauge core biopsies are sufficient for diagnosis. However, in our institution, we have a renal pathology technician present at the time of the
procedure to confirm adequate tissue samples. Major complications, including hemorrhage, have been reported in 1.5%-3.4% of children, although this rarely requires active management, such as transarterial embolization [11]. Nephrostomy and Other Genitourinary Intervention Percutaneous cannulation of the renal tract is a high-risk procedure for hemorrhage, and, therefore, it is essential to correct any coagulopathy. Antibiotic prophylaxis is highly recommended [11]. Nephrostomy The indications for pediatric nephrostomy are similar to those in the adult setting. The most common indication is an obstructed (potentially infected) renal collecting system due to various causes, including urolithiasis, hematoma, mycetoma, anatomical pelviureteric or vesicoureteric junction obstruction, or extrinsic masses [11]. The patient is positioned prone or semiprone. Because a nephrostomy procedure is more painful than a renal biopsy, adequate sedation is
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using intravenous urography to delineate the calyceal anatomy [11]. Communication with the urologist is essential before obtaining access for percutaneous nephrolithotomy to ensure that the site of access simplifies the process of stone removal, thereby reducing the length of the urologic procedure and the need for repeated intervention. Stone-free rates after a single session range from 86.9%- 98.5% [13]. Access is obtained with the patient lying prone or semiprone. The nephrostomy can be performed by direct puncture directed at the calculus, or of a dilated calyx obstructed by the calculus (Figure 3). When there is a significant stone burden that involves multiple lower pole calyces, a superior calyceal puncture may aid in avoiding multiple percutaneous nephrolithotomies [16].
Figure 2. Transjugular liver biopsy. A 2-year-old boy with a coagulopathy that required a liver biopsy. The armored sheath was placed into the right hepatic vein (white arrows) with both fluoroscopic and ultrasound imaging. The ultrasound (black arrowheads) enabled a safe biopsy to be performed without traversing the liver capsule with the biopsy needle (black arrow).
essential. Visualization and access is typically easier in the pediatric population due to patient size and less subcutaneous fat. However, careful periprocedural ultrasound is needed to identify the ideal calyx to access and to avoid bowel. Various access needles can be used. Micropuncture sets are often used, especially when there is minimal pelvicaliceal dilatation. However, in neonates and infants, micropuncture technique may have reduced success due to the thin renal parenchyma being indented but not traversed by the 5F dilator, which can result in malpositioning of the nephrostomy tube [12]. Percutaneous nephrostomies can provide access for ureteric intervention. As in adults, ureteric obstruction can be treated with internal-external nephrostomies or double-J ureteric stents. Anastomotic ureteric strictures related to renal transplantation can be treated with balloon dilation followed by insertion of a ureteric stent. Percutaneous Nephrolithotomy Pediatric patients account for approximately 1%-3% of all patients with urolithiasis [13,14]. They are at high risk for recurrence, and a significant number of the patients have a metabolic predisposition [14]. Imaging is essential for treatment planning, with ultrasound being the imaging modality of choice. However, there are differences of opinion as to whether CT is helpful. Some researchers think that CT optimizes treatment and access planning, and can identify those patients with a retrorenal colon, which has a reported incidence of 1%-14% [15]. Other researchers recommend
Figure 3. Percutaneous nephrolithotomy. A 19-month-old girl with sacral agenesis, cloacal malformation, and solitary left kidney, with a staghorn calculus. (A) Volume rendered coronal image from a noncontrast computed tomography, showing the large left staghorn calculus (arrows). (B) A fluoroscopic image of dual percutaneous guidewires down the left ureter (white arrows), with a 14F peel-away sheath left as an access conduit for stone removal (black arrows).
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Endoluminal and Percutaneous Gastrointestinal Intervention Treatment of Esophageal Strictures There are multiple causes of esophageal strictures in the pediatric patient. In our institution, as elsewhere, the most common cause that requires intervention is a postsurgical stricture related to esophageal atresia repair [7]. Other causes include achalasia, eosinophilic esophagitis, strictures related to fundoplication, and ingestion of corrosives (Figure 4). Fluoroscopic-guided balloon dilation of the esophageal stricture is our treatment of choice. Esophageal dilation is typically performed with the patient under general anesthetic with patient intubation by using a cuffed endotracheal tube for airway protection, thereby reducing the risk of aspiration. After a diagnostic contrast esophagram is performed, balloon dilation is performed over a guidewire. The balloon size depends on patient size, the cause and degree of stricture, and previous intervention. The aim of the procedure is to adequately dilate the esophagus without causing perforation, a complication that occurs in fewer than 1% of cases and more commonly in strictures related to corrosive ingestion than surgery [17,18]. For very high-grade strictures, to minimize the risk of esophageal perforation and possible mediastinitis, is best to consider serial dilation over more than one session rather than attempting to achieve complete relief of the stricture at one sitting. Success is confirmed by relief of symptoms, and the procedure can be repeated if symptoms recur. Although the risk of perforation is rare, there is
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controversy as to the need for a postprocedure esophagram as well as the necessity of the child remaining nil by mouth for a period of time [18]. In our institution, we keep the patient nil by mouth for 1 hour, then sips of clear fluids for 24 hours, then full fluids for a further 24 hours before commencing a normal diet as tolerated. The use of concomitant acid blockers is important because many strictures are aggravated by reflux. Indications for esophageal stents in the pediatric population are not well-defined but include recurrent severe strictures after balloon dilation, often due to surgery or corrosive ingestion (Figure 4), and esophageal leaks [19]. Various, usually removable, esophageal stents have been used in children, including modified tracheobronchial stents [20], silicon stents [21], and biodegradable stents [22], with good results. These ideally should be removed no later than 4-6 weeks to reduce the risk of mucosal adhesion and ingrowth [19]. Large and Small Bowel Balloon Dilation Small bowel and colonic strictures also can be treated with balloon dilation [23,24]. Stable access of the duodenum can be difficult when using a peroral approach due to overdilation of the stomach and fundal looping of guidewires (Figure 5). If a gastrostomy is available, it greatly simplifies stable access to the stricture [17]. Gastrostomy Gastrostomy (G)-tube insertion can be done for patients who are unable to ingest enough oral nutrition but who have
Figure 4. Caustic esophageal stricture. A 4-year-old girl who swallowed bleach. (A) Esophagram, showing local focal stricture (black arrows), with 2 focal perforations leaking into the right pleural space (white arrows). (B) Snare retrieval (white arrow) of an orally placed guidewire (black arrow) via a previously placed gastrostomy. (C) This procedure enabled stable access for the deployment of 2 covered self-expanding esophageal stents with no subsequent leak (arrows).
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Figure 5. Duodenal stricture dilation. A 15-year-old patient with chronic inflammatory disease of the antrum and proximal duodenum, which resulted in a tight stricture. (A) A stricture identified on T2-weighted coronal magnetic resonance imaging (arrow). (B) The stricture was crossed (arrow) by using fluoroscopy. (C, D) The stricture (arrow) was dilated with a 12-mm balloon.
adequate bowel for absorption, including neurologically impaired children and those patients with structural or functional esophageal abnormalities, high metabolic needs, or severe illness [25]. The procedure can be performed endoscopically, surgically, or laparoscopically, or by using image guidance. Image-guided G-tube insertion is performed by using a combination of ultrasound and fluoroscopic guidance, with either an antegrade or retrograde technique [25]. The procedure can be performed with the patient under sedation. The ideal puncture position for the G tube is lateral to the rectus muscle and approximately 2 cm below the costal margin, which allows for patient growth. We use the retrograde technique in our institution. This involves percutaneous puncture of the gas-insufflated stomach followed by insertion of 2 Cope pediatric retention sutures (Cook Medical, Bloomington, IN), which are used to bring the gastric wall and abdominal wall in direct contact and reduce the risk of an intraperitoneal gastric leak. A G tube can then be inserted over a guidewire. Both the nasogastric tube and the G tube should be left on free drainage overnight before starting a slow build up to full feeds. The stay sutures can be cut at the skin after 2 weeks. The antegrade approach uses a G tube with a fixed disk on one end, which avoids the need for stay sutures. There are cases of bowel obstruction due to these disks, which caused abscess formation and perforation [26].
Minor pneumoperitoneum is a common adverse effect of the procedure and can be aspirated by using a 27-gauge needle if there is significant pneumoperitoneum [25]. The most serious complication is peritonitis, which occurs in approximately 3% of cases [25,27]. G tubes need to be left for about 6 weeks to allow for a well-healed tract, which reduces the risk of separation of the gastric and anterior abdominal walls. After 6 weeks, the small-bore (typically 5F-8F) pigtail catheter can be upsized to a Mic-Key lowprofile G tube (Kimberley-Clark, Dallas, TX) which is both easier to use and esthetically more pleasing than a pigtail catheter. Gastrojejunostomy Insertion Transgastric jejunostomy tubes may be needed in some patients to reduce the incidence of significant reflux. A gastrojejunostomy (GJ) tube can either be a single lumen tube or a dual lumen tube with a gastric port. These tubes can be placed at the time of the initial gastrostomy or later, as required (Figure 6). Various GJ tubes are available, some that require adjustment of the jejunal component length. Jejunostomy tubes also can be placed through existing gastrostomy tubes for ease of placement and to reduce the risk of gastroperitoneal dehiscence, which is particularly useful for surgically placed gastrostomies because a 5F GJ tube
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Figure 6. Gastrojejunostomy insertion. Retrograde insertion of gastrojejunostomy tube. (A) Percutaneous puncture of the gastric bubble (arrow) with both nasojejunal and nasogastric tubes in situ. (B) The stay-sutures (white arrow) are inserted, followed by a hockey stick catheter (black arrow), which is passed into the jejunum and exchanged over a guidewire for the gastrojejunostomy tube.
fits snugly into an externally cut 12F gastrostomy tube. Of note, jejunostomy tubes can cause intussusception and perforation [25]. Percutaneous Cecostomy Cecostomy is a treatment for fecal incontinence, by providing an access port for regular antegrade enemas. The pediatric causes of fecal incontinence include spinal dysraphism, Hirschsprung disease, chronic constipation, other structural or functional anorectal abnormalities, and neurogenic bowel [26]. In these patients, overflow incontinence occurs and regular enemas can reduce the incidence of this debilitating condition. Percutaneous cecostomy is a relatively simple procedure first advocated by Shandling et al [28]. Percutaneous puncture is performed to place 1 or 2 Cope stay sutures (Cook Medical), followed by another puncture for insertion of a guidewire and, after tract dilation, an 8.5F pigtail cecostomy tube. After 6 weeks, this pigtail catheter usually is replaced with a Chait Trapdoor cecostomy tube (Cook Medical) due to its low profile and unobtrusive appearance (Figure 7). Percutaneous cecostomy in pediatric patients is a very successful procedure, particularly for those with neurogenic fecal incontinence, and is a low-risk procedure, with minimal complications [29,30].
commonly performed by using a Roux-en-Y, and ERCP is then not possible. In these cases, biliary obstruction can be investigated and treated by using percutaneous transhepatic cholangiography (PTC) [31]. The PTC success rate, even of nondilated systems, is higher than 90%, with an approximately 11% minor complication rate [32]. In neonates with cholestatic jaundice, there are multiple possible causes, including biliary atresia. Percutaneous cholecystocholangiography is an alternative to laparoscopic cholangiography in cases of cholestatic jaundice in which the
Hepatobiliary Intervention The majority of pediatric biliary interventions are performed on liver transplantation recipients, and, therefore, cases are concentrated in transplantation centres [31]. Another common indication is the evaluation of neonatal cholestasis. The risk of sepsis, although less than 1%, is serious. Therefore, appropriate antibiotic prophylaxis is essential [32]. Biliary investigation of nontransplanted livers is usually performed by endoscopic retrograde cholangiopancreatography (ERCP). Liver transplantations are
Figure 7. Chait cecostomy. Tubogram through the Chait tube, confirming its correct location within the cecum.
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Figure 8. Cholecystocholangiogram. An 8-week-old neonate with jaundice that was concerning for biliary atresia. (A) An ultrasound, demonstrating the presence of a collapsed gallbladder (arrows). (B) Percutaneous cholecystocholangiogram via cannulation of the gallbladder (black arrow), demonstrating a normal cystic duct (white arrowhead), normal common bile duct (white arrows), and attenuated intrahepatic bile ducts (black arrowheads), thereby excluding the diagnosis of biliary atresia.
gallbladder can be identified on ultrasound [33,34]. This occurs in types 1 and 3 of biliary atresia, which represent approximately 22% of biliary atresia cases. The procedure involves percutaneous cannulation of the gallbladder by using a 22- to 27-gauge needle. Contrast is then injected to identify any abnormality with the biliary tree (Figure 8). Due to the needle size, there is minimal risk, and there should be no significant complications [33,34]. Other Gastrointestinal Interventions Salivary Glands Sialorrhea or drooling is normal in children younger than 4 years of age. In children older than this, it is abnormal and may be due to a neurologic disorder, for example, cerebral palsy [35]. Approximately 90% of saliva is produced by the
submandibular and parotid glands. Ultrasound-guided injection of botulinum toxin A into the parotid and submandibular glands has been used successfully to reduce the amount of drooling. The procedure is effective in about 70% of patients and has a average duration of between 2 and 4.6 months [35]. Minor complications, such as dry mouth, are common. The most concerning major complications are difficulties swallowing, which results in aspiration pneumonia, or inadvertent injection of the facial nerve, which results in reversible facial nerve palsy. Botulinum toxin also is injected into the muscles around the hip joint as a treatment for hip pain in patients with cerebral palsy and hip spasm [36]. Salivary duct stenosis is uncommon in children, with the most common cause of obstructive sialadenitis being debris and/or calculi [37,38]. Fluoroscopic-guided balloon dilation has been used as a successful treatment for duct stenosis when it does occur [17,37].
Figure 9. Stent insertion for tracheal stenosis. A 23-month-old patient with tracheomalacia and stenosis, resulting from aberrant left pulmonary artery (‘‘pulmonary sling’’). (A) A tracheogram, showing stenoses of the trachea and left and right main bronchi (arrows) after attempted surgical reconstruction. (B) Stent reconstruction of the distal trachea and the right and left mainstem bronchi, with resultant wide patency.
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Other Pediatric Interventions Tracheobronchial Intervention Tracheobronchial intervention for pediatric airway obstruction and stenosis is a complex entity that requires the involvement of a multidisciplinary team. This has been reviewed in greater detail elsewhere [7,39,40]. Balloon dilation and stenting have been used to treat tracheomalacia, bronchomalacia, tracheal obstruction, and postoperative tracheal stenosis (Figure 9). Many questions remain regarding the indication for stenting, the type of stent to use, and the durability and/or long-term complication profile of these stents. Musculoskeletal Intervention Musculoskeletal intervention in pediatric patients mirrors those in adults, including bone biopsies, spinal pain procedures (eg, nerve root blocks), joint injections, and radiofrequency ablation of osteoid osteomas [26]. Conclusion The majority of the procedures covered in this article are also performed on the adult population. Most physicians are aware that the concept that the ‘‘pediatric patient is a small adult’’ is wrong. When dealing with an adolescent, the majority of IR procedures are identical in technique to those performed on adults. However, for younger children, a wide variety of techniques and equipment is needed to cope with variations in body size and physiology. As more PIR procedures are performed, a greater awareness of the different techniques can guide those in a general radiology department. This awareness, combined with the introduction of adult complex interventional procedures to the pediatric population, reinforces the nonmedical truism that, when PIR is concerned, ‘‘adults are just big kids.’’ References [1] Cravero JP, Beach ML, Blike GT, et al. The incidence and nature of adverse events during pediatric sedation/anesthesia with propofol for procedures outside the operating room: a report from the Pediatric Sedation Research Consortium. Anesth Analg 2009;108:795e804. [2] Malloy PC, Grassi CJ, Kundu S, et al. Consensus guidelines for periprocedural management of coagulation status and hemostasis risk in percutaneous image-guided interventions. J Vasc Interv Radiol 2009; 20(Suppl):S240e9. [3] Brenner D, Elliston C, Hall E, et al. Estimated risks of radiationinduced fatal cancer from pediatric CT. AJR Am J Roentgenol 2001; 176:289e96. [4] Alliance for Radiation Safety in Pediatric Imaging. Steps for radiation safety in pediatric interventional radiology. Available at: http://spr. affiniscape.com/associations/5364/ig/index.cfm?page¼603. Accessed December 13, 2011. [5] Heran MK, Marshalleck F, Temple M, et al. Joint quality improvement guidelines for pediatric arterial access and arteriography: from the Societies of Interventional Radiology and Pediatric Radiology. J Vasc Interv Radiol 2010;21:32e43. [6] Hogan MJ, Hoffer FA. Biopsy and drainage techniques in children. Tech Vasc Interv Radiol 2010;13:206e13.
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