CLINICAL STUDY
Image-Guided Pediatric Ureteric Stent Insertions: An 11-Year Experience Madeleine Sertic, Joao Amaral, MD, Dimitri Parra, MD, Michael Temple, MD, and Bairbre Connolly, MB
ABSTRACT Purpose: To report the technical success and complication rates for double J ureteric stent placements by interventional radiologists in children. Materials and Methods: A retrospective analysis of double J ureteric stents placed between January 2001 and December 2011 was conducted. Data collected included patient demographics, procedural details (indication, double J stent size, access approach, concurrent procedures), technical and functional success, tube dwell time, and procedure-related complications. Descriptive statistics were employed. Placement of 59 double J ureteric stents was attempted in 49 procedures performed on 35 pediatric patients (26 boys and 9 girls) with a mean age of 7.3 years (range, 22 d–17.9 y; median age, 4 y) and a mean weight of 22 kg (range, 2.5–70 kg). Results: There were 44 de novo double J stent insertion attempts: 20 one-stage procedures (17 anterograde, 3 retrograde through the urethra) and 24 two-stage anterograde procedures through an existing nephrostomy tube. There were 15 exchanges; 11 were anterograde, and 4 were retrograde (2 urethral, 2 Mitrofanoff). Of 49 procedures, 15 were performed as combined procedures with a urologist. Technical success was 95% (56 of 59), and primary functional success was 95% (53 of 56). Complications included two minor complications occurring during the procedure and four complications occurring after the procedure. Conclusions: Image-guided insertion of a double J ureteric stent is an effective treatment for pediatric urologic obstructive conditions. The procedure is both technically and functionally successful in a high percentage of pediatric patients.
Pediatric interventional uroradiology techniques have evolved since the 1970s and play an important role in pediatric urologic care (1). Although renal biopsy and nephrostomy tube insertion are the most common pediatric interventional nephrourologic procedures, placement of double J ureteric stents is also frequently performed. Most ureteric stent insertions are performed cystoscopically by urologists; less often, procedures are performed by interventional radiologists, or combined procedures are performed by interventional radiologists and urologists. Double J stents are inserted to relieve or prevent ureteral obstruction (2). In children, ureteric obstruction can be caused by various conditions, including congenital or postoperative ureteropelvic junction obstruction, From Image Guided Therapy, Diagnostic Imaging, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada M5G 1X8 Received September 13, 2013; final revision received March 13, 2014; accepted March 27, 2014. Address correspondence to B.C.; E-mail: [email protected]
congenital or postoperative ureterovesical junction obstruction, calculi, surgical strictures (after transplant or ureteric implantation), and strictures from malignancy or treatment of malignancy (eg, radiation). Accurate placement of a double J stent in children can be difficult because of patient size, structural congenital anatomic abnormalities, or both. Cases are being increasingly referred by urologists to interventional radiologists to avail of their technical expertise and skill in fluoroscopic guidance as well as the range of devices available for difficult stent insertion. After insertion, complications such as flank pain, dysuria, frequency, urgency, and lower urinary tract symptoms frequently occur (2), and mild hematuria is almost always encountered (3). Ureteric stents require elective interval exchanges because of issues of encrustation and bacterial colonization (4). The purpose of this study is to report the technical success and complication rates for double J ureteric stent placements by interventional radiologists in children.
None of the authors have identified a conflict of interest. & SIR, 2014
MATERIALS AND METHODS
J Vasc Interv Radiol 2014; XX:]]]–]]]
Approval was obtained from the institutional research ethics board for this retrospective study. The clinical
http://dx.doi.org/10.1016/j.jvir.2014.03.028
2
’
Image-Guided Pediatric Ureteric Stent Insertion
setting was a tertiary care pediatric hospital. Medical records of all patients who underwent a ureteric double J stent insertion or exchange between January 2001 and December 2011 were retrospectively reviewed. The study group included patients with double J stent insertions or exchanges performed by interventional radiologists and insertions or exchanges performed as combined procedures with interventional radiologists and urologists. Procedures performed solely by urologists were not included. Cases were identified through the picture archiving and communication system and the interventional radiology database (EshIGT; Esh Software Design & Implementation LTD, Toronto, Ontario, Canada), a database that is prospectively collected. Information was retrospectively collected from imaging studies, procedural reports, patient charts, and clinic correspondence. Data gathered for analysis included patient demographics (age, gender, weight); primary diagnosis and indication for treatment; length and size of the stent inserted; method of insertion; any concurrent procedures; and outcomes, including dwell period, removals, and any resulting complications. Because patients may have had more than one stent inserted over a period of time, each double J stent was counted individually for data collection and analysis. Similarly, a procedure involving a bilateral insertion counted as two stents in the analysis. Descriptive statistics (mean, median, and range for continuous measures; frequency and percentages for categorical measures) are reported.
Sertic et al
’
JVIR
collecting system to gain access down into the ureter and bladder. Retrograde insertion involved access via the urethra or the bladder, advancing in a retrograde fashion via the ureteric orifice into the renal collecting system. Double J stents placed with a urologist and interventional radiologist working together were classified as combined. Concurrent procedures included other procedures performed by urologists, interventional radiologists, or other clinicians under the same anesthetic. The number and type of complications directly related to ureteric stent insertion were recorded. Complications were categorized as occurring during the procedure or after the procedure. Complications that arose after insertion of the double J stent was completed were subdivided into early complications (o 24 h) and late complications (4 24 h). Complications that arose during the procedure were classified as major or minor, in accordance with Society of Interventional Radiology (SIR) guidelines (Table 1) (5). Technical success was defined as placement of a double J stent in the ureter, with the upper “J” in the patient’s renal collecting system and the lower “J” in the patient’s urinary bladder. Functional success was defined as adequate urinary drainage through or around the stent to achieve decompression of the collecting system, as judged clinically, biochemically, and by ultrasound. Dwell time of the stent was calculated in days from the date of insertion to the date of removal.
Techniques Definitions A double J ureteric stent insertion was defined as de novo placement of a double J ureteric stent, where no prior stent was present. An exchange was defined as the replacement of an existing stent with a new stent, using over-the-wire techniques. Insertions were classified as one stage when the entire access and stent placement was performed during one procedure. Insertions were classified as two stage when prior access had already been established (ie, through an existing nephrostomy). Anterograde insertions involved placement from the renal
All ureteric double J stent insertions were performed in the interventional radiology suite by a pediatric interventional radiologist using a combination of sonographic and fluoroscopic guidance. All procedures were performed under general anesthesia (type and depth at the discretion of the anesthesiologist), and antibiotic prophylaxis was employed. In anterograde insertions, the patient was placed in a prone or prone oblique position. The pelvicalyceal system of the appropriate kidney was identified and punctured under ultrasound guidance, using a micropuncture technique and
Table 1 . Complications of Double J Stent Insertion Classification
Complication
During procedure Minor B Urine leak (n ¼ 1)
Necessary Treatment Foley catheterization
Large pleural effusion, right lung collapse (n ¼ 1)
Fluid aspiration from pleural space during procedure
Moderate hematuria (n ¼ 1) Klebsiella oxytoca infection and stent blockage (n ¼ 1)
None Full course of intravenous and oral antibiotics
After procedure Early Late
Urine leak owing to undersized stent (n ¼ 1)
Replacement with larger stent
Enterobacter cloacae urinary tract infection (n ¼ 1)
PICC insertion for antibiotic treatment
PICC ¼ peripherally inserted central catheter.
Volume XX
’
Number X
’
Month
’
2014
Neff Percutaneous Access Set (Cook, Inc, Bloomington, Indiana) (3,6). An 18-gauge/16-gauge needle and 0.035-inch wire may be used in neonates or infants (7). After puncture, the wire was inserted into the collecting system and advanced down the ureter for stability. The tract was dilated commonly using a dilator with a peel-away sheath, and the sheath was left in the renal pelvis to maintain pelvic access and to facilitate wire and catheter exchanges. The access wire was maintained through the sheath as a safety wire. A second wire (Glidewire; Terumo, Tokyo, Japan; or Amplatz Super Stiff Guidewire; Boston Scientific, Natick, Massachusetts) was advanced down the ureter into the bladder using a directional catheter (eg, Bernstein or JB1 catheter; Cook, Inc). In the event of a tight ureteric stricture, balloon dilation was performed before double J stent placement. The directional catheter was removed, and the double J stent (Cook, Inc) was advanced over the wire. The wire was removed while positioning the distal “J” in the bladder and the proximal “J” in the renal pelvis. The length of the double J stent was calculated in several ways: by measuring the catheter using an external radiopaque ruler placed under the patient, by measuring the length of the guide wire required to reach the bladder, by using an internal radiopaque graduated catheter placed in the ureter (Cook, Inc), or by a formula estimation where stent length (cm) ¼ patient age (y) þ 10 (8). When the distal coil of the double J stent was in the bladder, the wire was withdrawn as the pusher advanced the proximal coil into the renal pelvis, using the radiopaque tip of the pusher as a marker. The decision to place a temporary nephrostomy was at the discretion of the operator (eg, if there was significant bleeding or clot (3) or concern regarding the ability to drain adequately around the double J stent). Retrograde insertions were performed with the patient in the supine position. Retrograde placement was most often performed under direct cystoscopic vision by a urologist. In this study, only placements performed by an interventional radiologist or placements performed as a combined procedure with a urologist were included in the analysis. Retrograde placements by an interventional radiologist via a Mitrofanoff appendicovesicostomy (surgical connection between the skin at the umbilicus and the urinary bladder using the appendix as a conduit) were also included. The technique of “body flossing” was employed in difficult cases. This technique involved a wire advanced from above, through the renal collecting system, snared in the bladder, and exited either via the urethra or a Mitrofanoff appendicovesicostomy. Passage of the wire in the reverse direction was also possible to achieve body flossing. Body flossing provided greater support to the wire in cases of tight strictures, difficult balloon dilation, or facilitated passage of the double J stent over the wire. It was performed either as a combined procedure with a urologist and interventional radiologist or by an interventional radiologist alone.
3
Double J stent exchanges were performed in an anterograde or a retrograde fashion. Anterograde exchanges by the interventional radiologist involved snaring the proximal double J stent in the renal collecting system. If an internal-external nephroureterostomy stent (Salle Intraoperative Pyeloplasty Stent Set; Cook, Inc) was in place, the exchange was facilitated by placing a wire directly through the indwelling stent from above, down into the bladder, over which the double J stent was then placed. These procedures were considered exchanges rather than two-stage insertions because of the preexisting stent in the ureter. Retrograde exchanges performed by the interventional radiologist involved snaring the double J stent from below (the bladder) via the urethra or through a Mitrofanoff appendicovesicostomy using a snare (25 mm) and a directional catheter. Bladder distention was required to open the folds of augmented bladders. The distal tip of the indwelling stent was snared within the bladder and exteriorized about 1 inch. Through the partially exteriorized double J stent, a Glidewire or an Amplatz Super Stiff Guidewire was passed retrograde into the pelvicalyceal system, and the double J stent was removed. A catheter was advanced over the wire to opacify the pelvicalyceal system as a landmark for placement of the new double J stent. The new double J stent was inserted over the guide wire.
Demographics Over an 11-year period, placement of 59 double J stents was attempted during 49 procedures on 35 pediatric patients (26 boys, 9 girls). The mean age of the patients at double J stent placement was 7.3 years (range, 22 d– 18 y; median age, 4 y), and the mean weight was 21.9 kg (range, 2.5–70 kg; median, 16.9 kg). The diagnoses of the 35 patients are shown in Table 2. The most frequent indications for stent placements were the management or prevention of worsening hydronephrosis or hydroureteronephrosis, infection, and exchanges of existing stents. Almost 80% of double J stents were placed in boys (n ¼ 47; 79.7%). Table 2 . Underlying Diagnoses for Double J Stent Insertions
Underlying Diagnoses
No. Patients
No. Double J Stents
Congenital ureteric strictures UPJ obstruction
7 6
19 6
Malignancy
5
11
Metabolic/stone disease Renal transplant
5 4
8 5
Prior posterior urethral valves
3
4
Prior bladder exstrophy Miscellaneous*
2 3
2 4
Note. Several patients had more than one primary diagnosis or indication for drainage. UPJ ¼ ureteropelvic junction. n Neurogenic bladder (n ¼ 1), prune-belly syndrome (n ¼ 1), multicystic dysplastic kidney disease (n ¼ 1).
4
’
Image-Guided Pediatric Ureteric Stent Insertion
Sertic et al
RESULTS Placement of 59 double J stents was attempted, 44 of 59 (75%) insertions and 15 of 49 (25%) exchanges, in 35 patients. Nine patients had multiple stents placed (bilateral insertions [n ¼ 4 of 35; 11%], repeated stent exchanges [n ¼ 2 of 35; 6%], or both [n ¼ 3 of 35; 9%]). Three placements failed (n ¼ 3 of 59; 5%). There were 10 bilateral insertions—20 of 59 double J stents (34%). In one instance, a patient had a duplicated right system, and a double J ureteric stent was inserted into each of the patient’s two right ureters. In 39 procedures (66%), a nephrostomy tube was left in situ. In 13 of 59 (22%) procedures (8 insertions, 5 exchanges), balloon dilation of the ureter was required to place the double J stent. Balloon sizes ranged from 3–6 mm diameter. A summary of stent placement techniques employed is provided in Table 3. Of 44 insertions, 3 (7%) were retrograde; of 15 exchanges, 11 (73%) were anterograde, and 4 (27%) were retrograde (Table 3). An interventional radiologist performed 44 of 59 (75%) double J stent procedures, and an interventional radiologist together with a urologist performed 15 of 59 (25%) double J stent procedures: 9 (60%) insertions (including lithotripsy [n ¼ 4], cystoscopy [n ¼ 2], and retrograde through the urethra [n ¼ 3]) and 6 (40%) exchanges (3 anterograde and 3 retrograde—through the urethra [n ¼ 2] and through a Mitrofanoff appendicostomy [n ¼ 1]). The urologist requested assistance in 9 of the 15 cases because of technical difficulties and inability to perform the exchanges cystoscopically (exact technical difficulty could not be determined retrospectively). Body flossing was employed in three instances. These variations all were performed as combined procedures with a urologist. There were 15 of 59 (25%) combined double J stent procedures performed with a urologist, including lithotripsy (n ¼ 4 of 15; 27%), diagnostic cystoscopy (n ¼ 2 of 15; 13%), exchanges (n ¼ 6 of 15; 40%), and one-stage retrograde insertions (n ¼ 3 of 15; 20%). Multiple concomitant procedures were performed in the same sitting in 45 of 59 (92%) procedures, including 41 nephrostomy tube insertions or exchanges, 13 ureteric dilations, 6 cystoscopies, 3 cystograms, 4 nephrolithotomies (2 laser Table 3 . Summary of Double J Stent Placement Techniques Insertions (n ¼ 44) One-stage
Anterograde (percutaneous) Retrograde (through urethra)
n ¼ 17 n¼3
Two-stage
Through nephrostomy
n ¼ 24
Exchanges (n ¼ 15) Anterograde Percutaneous Through nephrostomy Through nephrouterostomy Retrograde Through urethra
n¼4 n¼2 n¼2
Through Mitrofanoff appendicovesicostomy n ¼ 2
’
JVIR
lithotripsies), 2 pyelograms, 1 abdominal drainage, 1 chest tube insertion, and 1 central venous line insertion. Stent size and length varied according to patient size. Stent sizes ranged from 3.7-F to 8-F (3.7-F, n ¼ 9; 4.7-F, n ¼ 22; 5-F, n ¼ 5; 6-F, n ¼ 14; 8-F, n ¼ 6). The intended stent size was not recorded in the three technical failures (see later on). Stent length ranged from 10–26 cm (10 cm, n ¼ 10; 12 cm, n ¼ 9; 14 cm, n ¼ 6; 16 cm, n ¼ 5; 18 cm, n ¼ 4; 20 cm, n ¼ 3; 22 cm, n ¼ 11; 24 cm, n ¼ 6; 25 cm, n ¼ 1; 26 cm, n ¼ 1). Of 59 attempted stent placements, 56 (95%) were technically successful. Technical failure occurred on two nonconsecutive occasions in a patient with multiple congenital severe ureteric strictures (n ¼ 2). The other technical failure involved an inability to cannulate the ureter in a 54-day-old (3.9-kg) patient with a urinoma secondary to posterior urethral valves—a nephrostomy tube was left instead (n ¼ 1). Of the remaining 56 stents, 53 (95%) were functionally primarily successful, and 3 (5%) were initial functional failures. Two functional failures occurred in a 3.5-kg neonate with hyperoxaluria and ureteric strictures. Both 3.7-F stents were positioned appropriately but proved too small for optimal drainage, resulting in urinary retention and leakage around the patient’s nephrostomy tubes. The stents were replaced with 4.7-F double J stents, which functioned well (secondarily functionally successful). The last functional failure occurred in a patient in whom the double J stent was inserted but because of the small size of the patient’s collecting system, the coil in the upper collecting system did not form properly and subsequently migrated anterograde into the bladder (n ¼ 1). This stent also required replacement. Among the patients in whom a double J stent was successfully placed, the primary functional success was 95% (n ¼ 53 of 56), and the remainder were secondarily functionally successful.
Complications Two complications occurred during the procedure, classified as SIR Minor B (ie, nominal therapy, no consequence) (5). One insertion of a double J ureteric stent caused a small perforation in the ureter and a urine leak with urinoma and associated ileus, which resolved with Foley catheterization (n ¼ 1, Minor B). The other complication involved a patient with multiple complex medical issues who developed an acute pleural effusion with associated lung collapse during a combined lithotripsy procedure. The pleural effusion was thought to be caused by tracking into the chest of the irrigation fluid used during the lithotripsy. Urgent evacuation of the pleural fluid (350 mL of serosanguineous fluid) was required (n ¼ 1, Minor B). Complete reexpansion of the lung followed, with resolution of respiratory compromise and no sequelae. Four complications occurred after the procedure. There was one early complication that involved moderate
Volume XX
’
Number X
’
Month
’
2014
self-limiting hematuria that did not require transfusion. The three late complications included urine leak around nephrostomies from undersized bilateral double J stents, which was resolved by an exchange for larger stents (n ¼ 1); bacteriuria infection with Enterobacter cloacae which required a peripherally inserted central catheter for intravenous antibiotic treatment (n ¼ 1); and Klebsiella oxytoca treated with intravenous and oral antibiotics (n ¼ 1). The stent dwell times were calculated for 50 of the 56 stents successfully placed. Four stent removals were not performed at our institution, and two double J stents in one patient in whom stent placement was palliative treatment were still in place at the time of death. Mean dwell time was 113 days (range, 6–340 d; median, 96 d). A urologist removed 38 double J stents; 35 were removed cystoscopically, and 3 were removed during surgery (pyeloplasty [n ¼ 1], ureterectomy [n ¼ 1], nephroureterectomy [n ¼ 1]). An interventional radiologist removed 12 double J stents (12 of 50; 24%); 7 were removed during stent exchanges, and 5 were removed as a sole procedure. Mean time between double J stent exchanges performed by an interventional radiologist was 111 days (range, 8–305 d; median, 96 d).
DISCUSSION Double J ureteric stents are an effective means to relieve ureteric obstruction, and placement of a double J stent is one of the most common urologic procedures (2). Double J stents increasingly are placed by interventional radiologists (3,6). However, there is little in the literature describing pediatric image-guided ureteric stent placement. Roebuck (6) and Barnacle et al (3) published reviews on pediatric interventional uroradiology. Barnacle et al (3) reported the most common indications for pediatric ureteric intervention below the ureteropelvic junction were congenital or postoperative vesicoureteral obstruction, transplant-related ureteric stricture, and malignant ureteric obstruction. The findings of Barnacle et al (3) are similar to our experience (Table 2). Roebuck (6) commented that stents usually are placed in ureters after balloon dilation. Balloon dilation was employed in only 13 cases in our series, and double J stent placement was successful in all 13 cases. In three instances, balloon dilation enabled a double J stent to be placed successfully after a prior failure without balloon ureteroplasty. The overall 90% technical and functional success rate in the present study is comparable to reports in the current literature. Kljucevsek and Kljucevsek (9) outlined their experiences with percutaneous insertion of ureteric stents in 10 children with ureteral obstruction using an anterograde approach. They concluded that the imageguided percutaneous approach is useful when the endoscopic or retrograde approach is not an option. Our
5
results compare favorably with their 80% initial success rate (8 of 10 on first attempt; 100% success rate with second attempt). Although the anterograde approach of image-guided ureteric stent insertion has been in practice since the 1980s, the retrograde approach is still relatively novel. In 2007, Carrafiello et al (10) described success with fluoroscopically guided retrograde replacement of ureteric stents in adult patients through the urethra. They recommended the fluoroscopic approach when the cystoscopic approach either fails or is suboptimal. Cystoscopy relies on the ability to see through clear urine. Fluoroscopic exchanges have an advantage when it is impossible to see through urine (eg, bloody, mucoid, or cloudy urine from an augmented bladder) as well as the advantage of the smaller caliber of the devices, which are easier to manipulate inside the bladder and consequently involve a lower risk of causing bleeding (10). Other studies reported fluoroscopically guided replacement success rates ranging from 97%–100% (11–15). The retrograde exchanges reported in the present study were similarly successful without any complications. In patients with a Mitrofanoff appendicovesicostomy, cystoscopic visualization of the ureteric orifices may be very difficult because of augmentation, cloudy mucus, and/or the unfavorable angle of access for a rigid cystoscope from the umbilicus. A fluoroscopic exchange using a snare and an angled catheter has significant advantages. Distention of the bladder to efface the mucosal folds of the augmented bladder and the use of an angled catheter for snaring are imperative The main disadvantage is the radiation dose associated with snaring, which is cumulative in a patient who may return for repeat exchanges. The issue of forgotten stents has been discussed in the literature (16–19). The recommended dwell times vary widely in the literature from exchanges at 6 weeks to 6 months, although double J stents can be left in place for 12 months without any issues (6,9,17). It is necessary to have a system in place (as arranged by a urologist or interventional radiologist) to ensure the timely exchange of a patient’s double J stent is not overlooked. Our practice goal is to exchange a double J stent electively at approximately 3 months. The mean dwell time of double J ureteric stents inserted by our department was 113 days (ie, 3.75 mo) (median, 96 d). Characteristic morbidity from symptomatic indwelling ureteric stents includes fever, dysuria, abdominal or flank pain, hematuria, and nocturia (4). Forgotten stents can become encrusted and fragment, causing ureteral obstruction. One study estimated a 6.9-fold increase in cost of care in patients with forgotten stents compared with patients with stents removed in a timely fashion (18). Bacterial colonization of an indwelling stent is common and may be clinically silent. The incidence of bacteriuria and urinary tract infection found in this group is likely an underestimate. Ben-Meir et al (20)
6
’
Image-Guided Pediatric Ureteric Stent Insertion
found there was no statistically significant correlation between rates of stent colonization and symptomatic urinary tract infection in children. They reported a 9.8% rate of subsequent urinary tract infection in their population (20), comparable to our rate of 8.9% (3 of 56). Enterococcus was found to be the most frequent pathogen, whereas Enterobacter species were the responsible pathogens in only 2.4% of cases (20). Yeniyol et al (21) also studied the rates of bacterial infection associated with double J stents and found Escherichia coli to be the most common pathogen, followed by Klebsiella. The difference in results between the most frequent bacterial colonizations (Enterobacter and Klebsiella) in the present study and the colonizations reported in the literature is likely due to the small number of confirmed infections in our small patient population. Hybrid rooms provide significant advantages for urologic procedures and facilitate multidisciplinary collaboration. Concurrent and combined procedures can be more readily accommodated in hybrid rooms in an anticipated planned manner for complex cases or in unplanned cases when one clinician experiences unexpected difficulties during a procedure. For example, when a two-stage anterograde insertion of a double J stent initially failed, a urologist was present and able to assist in a successful retrograde insertion, avoiding the need to abandon the procedure, reschedule it, and undergo a repeated general anesthetic for the patient. Conversely, in four cases when a urologist was unable to insert a ureteric stent, an interventional radiologist was able to insert a stent in three of the four cases. The immediate management of the child with acute pleural effusion and pulmonary collapse was also facilitated by the availability of ultrasound, fluoroscopy, and the expertise of the interventional radiologist to place a pleural catheter expeditiously. In this series of double J stents, 45 concurrent procedures were performed during the double J stent procedures. The collaboration between services in a hybrid room is important in a multidisciplinary approach to patient-centered care. The advantages far outweigh the logistical difficulties of bookings and case planning. The present study has several limitations, including that it was a retrospective review of a limited number of patients from a single institution. The wide range of pathologies; different approaches employed; the variety of devices, wires, catheters, and balloons used; and the unique challenges encountered in many of the individual cases are difficult to capture in a retrospective review such as this. The specific technical difficulties encountered in any one case that prompted the assistance of an interventional radiologist or urologist were not always clearly documented and could not be identified retrospectively. All insertions were performed by dedicated pediatric interventional radiologists in a tertiary care pediatric center. The collaboration with
Sertic et al
’
JVIR
urologists was an important additional factor in achieving the high success rate in more complex cases. Although the study includes a relatively large number of procedures, the number of individual patients is not large enough to determine statistically risk factors for complications of ureteric stent insertions. The full range of symptoms associated with double J stents may have been underreported because some children were too young or nonverbal, potentially resulting in an underestimate of their symptoms. Given the long time span of the study, some patients were lost to follow-up. Only a small number of patients had double J stents inserted in a retrograde fashion during the period of this review, and the outcomes of this technique cannot be comprehensively examined in this study. In conclusion, image-guided insertion of double J ureteric stents in children through an anterograde or a retrograde approach is an effective means for managing ureteric obstruction with a good success rate and an acceptable complication rate. In complex cases, various approaches may be required to achieve success. Access to hybrid rooms for performance of these types of procedures may be helpful.
REFERENCES 1. Mandell VS, Mandell MJ, Gaisie G. Pediatric urologic radiology. Intervention and endourology. Urol Clin North Am 1985; 12:151–168. 2. Mendez-Probst CE, Fernandez A, Denstedt JD. Current status of ureteral stent technologies: comfort and antimicrobial resistance. Curr Urol Rep 2010; 11:67–73. 3. Barnacle AM, Wilkinson AG, Roebuck DJ. Paediatric interventional uroradiology. Cardiovasc Intervent Radiol 2011; 34:227–240. 4. Richter S, Ringel A, Shalev M, Nissenkorn I. The indwelling ureteric stent: a ‘friendly’ procedure with unfriendly high morbidity. BJU Int 2000; 85:408–411. 5. Sacks D, McClenny TE, Cardella JF, Lewis CA. Society of Interventional Radiology clinical practice guidelines. J Vasc Interv Radiol 2003; 14(9 Pt 2): S199–S202. 6. Roebuck DJ. Genitourinary intervention in children. Pediatr Radiol 2011; 41:17–26. 7. Koral K, Saker MC, Morello FP, Rigsby CK, Donaldson JS. Conventional versus modified technique for percutaneous nephrostomy in newborns and young infants. J Vasc Interv Radiol 2003; 14:113–116. 8. Palmer JS, Palmer LS. A simple and reliable formula for determining the proper JJ stent length in the pediatric patient: age þ 10. Urol 2007; 70: 264. 9. Kljucevsek D, Kljucevsek T. Percutaneous insertion of double-J ureteral stent in children with ureteral obstruction: our experiences. J Pediatr Urol 2013; 9:188–192. 10. Carrafiello G, Lagana D, Mangini M, et al. Fluoroscopically guided retrograde replacement of ureteral stents. Radiol Med 2007; 112: 821–825. 11. White PG, Evans C. Minimally invasive removal of retained ureteric stents. Br J Urol 1990; 66:328. 12. Ellis JH, Brodeur FJ Jr, Marx MV, Sheffner SE. Superelastic guide-wire snare for removal of foreign bodies from the urinary tract. Radiology 1992; 183:871–873. 13. de Baere T, Denys A, Pappas P, Challier E, Roche A. Ureteral stents: exchange under fluoroscopic control as an effective alternative to cystoscopy. Radiology 1994; 190:887–889. 14. Boardman P, Cowan NC. Technical report: fluoroscopically guided retrograde ureteric stent retrieval and replacement using a guide catheter directed snare. Clin Radiol 1997; 52:308–309.
Volume XX
’
Number X
’
Month
’
2014
15. Wetton CW, Gedroyc WM. Retrograde radiological retrieval and replacement of double-J ureteric stents. Clin Radiol 1995; 50:562–565. 16. Singh I. Indwelling JJ ureteral stents—a current perspective and review of literature. Indian J Surg 2003; 65:405–412. 17. Fishman JR, Presto AJ 3rd. The forgotten ureteral stent. West J Med 1994; 160:569–570. 18. Sancaktutar AA, Sö ylemez H, Bozkurt Y, Penbegül N, Atar M. Treatment of forgotten ureteral stents: how much does it really cost? A costeffectiveness study in 27 patients. Urol Res 2012; 40:317–325.
7
19. Singh V, Srinivastava A, Kapoor R, Kumar A. Can the complicated forgotten indwelling ureteric stents be lethal? Int Urol Nephrol 2005; 37: 541–546 20. Ben-Meir D, Golan S, Ehrlich Y, Livne PM. Characteristics and clinical significance of bacterial colonization of ureteral double-J stents in children. J Pediatr Urol 2009; 5:355–358. 21. Yeniyol CO, Tuna A, Yener H, Zeyrek N, Tilki A, Coskuner A. Bacterial colonization of double J stents and bacteriuria frequency. Int Urol Nephrol 2002; 34:199–202.
Image-Guided Pediatric Ureteric Stent Insertions: An 11-Year Experience Madeleine Sertic, Joao Amaral, MD, Dimitri Parra, MD, Michael Temple, MD, and Bairbre Connolly, MB
ABSTRACT Purpose: To report the technical success and complication rates for double J ureteric stent placements by interventional radiologists in children. Materials and Methods: A retrospective analysis of double J ureteric stents placed between January 2001 and December 2011 was conducted. Data collected included patient demographics, procedural details (indication, double J stent size, access approach, concurrent procedures), technical and functional success, tube dwell time, and procedure-related complications. Descriptive statistics were employed. Placement of 59 double J ureteric stents was attempted in 49 procedures performed on 35 pediatric patients (26 boys and 9 girls) with a mean age of 7.3 years (range, 22 d–17.9 y; median age, 4 y) and a mean weight of 22 kg (range, 2.5–70 kg). Results: There were 44 de novo double J stent insertion attempts: 20 one-stage procedures (17 anterograde, 3 retrograde through the urethra) and 24 two-stage anterograde procedures through an existing nephrostomy tube. There were 15 exchanges; 11 were anterograde, and 4 were retrograde (2 urethral, 2 Mitrofanoff). Of 49 procedures, 15 were performed as combined procedures with a urologist. Technical success was 95% (56 of 59), and primary functional success was 95% (53 of 56). Complications included two minor complications occurring during the procedure and four complications occurring after the procedure. Conclusions: Image-guided insertion of a double J ureteric stent is an effective treatment for pediatric urologic obstructive conditions. The procedure is both technically and functionally successful in a high percentage of pediatric patients.
Pediatric interventional uroradiology techniques have evolved since the 1970s and play an important role in pediatric urologic care (1). Although renal biopsy and nephrostomy tube insertion are the most common pediatric interventional nephrourologic procedures, placement of double J ureteric stents is also frequently performed. Most ureteric stent insertions are performed cystoscopically by urologists; less often, procedures are performed by interventional radiologists, or combined procedures are performed by interventional radiologists and urologists. Double J stents are inserted to relieve or prevent ureteral obstruction (2). In children, ureteric obstruction can be caused by various conditions, including congenital or postoperative ureteropelvic junction obstruction, From Image Guided Therapy, Diagnostic Imaging, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada M5G 1X8 Received September 13, 2013; final revision received March 13, 2014; accepted March 27, 2014. Address correspondence to B.C.; E-mail: [email protected]
congenital or postoperative ureterovesical junction obstruction, calculi, surgical strictures (after transplant or ureteric implantation), and strictures from malignancy or treatment of malignancy (eg, radiation). Accurate placement of a double J stent in children can be difficult because of patient size, structural congenital anatomic abnormalities, or both. Cases are being increasingly referred by urologists to interventional radiologists to avail of their technical expertise and skill in fluoroscopic guidance as well as the range of devices available for difficult stent insertion. After insertion, complications such as flank pain, dysuria, frequency, urgency, and lower urinary tract symptoms frequently occur (2), and mild hematuria is almost always encountered (3). Ureteric stents require elective interval exchanges because of issues of encrustation and bacterial colonization (4). The purpose of this study is to report the technical success and complication rates for double J ureteric stent placements by interventional radiologists in children.
None of the authors have identified a conflict of interest. & SIR, 2014
MATERIALS AND METHODS
J Vasc Interv Radiol 2014; XX:]]]–]]]
Approval was obtained from the institutional research ethics board for this retrospective study. The clinical
http://dx.doi.org/10.1016/j.jvir.2014.03.028
2
’
Image-Guided Pediatric Ureteric Stent Insertion
setting was a tertiary care pediatric hospital. Medical records of all patients who underwent a ureteric double J stent insertion or exchange between January 2001 and December 2011 were retrospectively reviewed. The study group included patients with double J stent insertions or exchanges performed by interventional radiologists and insertions or exchanges performed as combined procedures with interventional radiologists and urologists. Procedures performed solely by urologists were not included. Cases were identified through the picture archiving and communication system and the interventional radiology database (EshIGT; Esh Software Design & Implementation LTD, Toronto, Ontario, Canada), a database that is prospectively collected. Information was retrospectively collected from imaging studies, procedural reports, patient charts, and clinic correspondence. Data gathered for analysis included patient demographics (age, gender, weight); primary diagnosis and indication for treatment; length and size of the stent inserted; method of insertion; any concurrent procedures; and outcomes, including dwell period, removals, and any resulting complications. Because patients may have had more than one stent inserted over a period of time, each double J stent was counted individually for data collection and analysis. Similarly, a procedure involving a bilateral insertion counted as two stents in the analysis. Descriptive statistics (mean, median, and range for continuous measures; frequency and percentages for categorical measures) are reported.
Sertic et al
’
JVIR
collecting system to gain access down into the ureter and bladder. Retrograde insertion involved access via the urethra or the bladder, advancing in a retrograde fashion via the ureteric orifice into the renal collecting system. Double J stents placed with a urologist and interventional radiologist working together were classified as combined. Concurrent procedures included other procedures performed by urologists, interventional radiologists, or other clinicians under the same anesthetic. The number and type of complications directly related to ureteric stent insertion were recorded. Complications were categorized as occurring during the procedure or after the procedure. Complications that arose after insertion of the double J stent was completed were subdivided into early complications (o 24 h) and late complications (4 24 h). Complications that arose during the procedure were classified as major or minor, in accordance with Society of Interventional Radiology (SIR) guidelines (Table 1) (5). Technical success was defined as placement of a double J stent in the ureter, with the upper “J” in the patient’s renal collecting system and the lower “J” in the patient’s urinary bladder. Functional success was defined as adequate urinary drainage through or around the stent to achieve decompression of the collecting system, as judged clinically, biochemically, and by ultrasound. Dwell time of the stent was calculated in days from the date of insertion to the date of removal.
Techniques Definitions A double J ureteric stent insertion was defined as de novo placement of a double J ureteric stent, where no prior stent was present. An exchange was defined as the replacement of an existing stent with a new stent, using over-the-wire techniques. Insertions were classified as one stage when the entire access and stent placement was performed during one procedure. Insertions were classified as two stage when prior access had already been established (ie, through an existing nephrostomy). Anterograde insertions involved placement from the renal
All ureteric double J stent insertions were performed in the interventional radiology suite by a pediatric interventional radiologist using a combination of sonographic and fluoroscopic guidance. All procedures were performed under general anesthesia (type and depth at the discretion of the anesthesiologist), and antibiotic prophylaxis was employed. In anterograde insertions, the patient was placed in a prone or prone oblique position. The pelvicalyceal system of the appropriate kidney was identified and punctured under ultrasound guidance, using a micropuncture technique and
Table 1 . Complications of Double J Stent Insertion Classification
Complication
During procedure Minor B Urine leak (n ¼ 1)
Necessary Treatment Foley catheterization
Large pleural effusion, right lung collapse (n ¼ 1)
Fluid aspiration from pleural space during procedure
Moderate hematuria (n ¼ 1) Klebsiella oxytoca infection and stent blockage (n ¼ 1)
None Full course of intravenous and oral antibiotics
After procedure Early Late
Urine leak owing to undersized stent (n ¼ 1)
Replacement with larger stent
Enterobacter cloacae urinary tract infection (n ¼ 1)
PICC insertion for antibiotic treatment
PICC ¼ peripherally inserted central catheter.
Volume XX
’
Number X
’
Month
’
2014
Neff Percutaneous Access Set (Cook, Inc, Bloomington, Indiana) (3,6). An 18-gauge/16-gauge needle and 0.035-inch wire may be used in neonates or infants (7). After puncture, the wire was inserted into the collecting system and advanced down the ureter for stability. The tract was dilated commonly using a dilator with a peel-away sheath, and the sheath was left in the renal pelvis to maintain pelvic access and to facilitate wire and catheter exchanges. The access wire was maintained through the sheath as a safety wire. A second wire (Glidewire; Terumo, Tokyo, Japan; or Amplatz Super Stiff Guidewire; Boston Scientific, Natick, Massachusetts) was advanced down the ureter into the bladder using a directional catheter (eg, Bernstein or JB1 catheter; Cook, Inc). In the event of a tight ureteric stricture, balloon dilation was performed before double J stent placement. The directional catheter was removed, and the double J stent (Cook, Inc) was advanced over the wire. The wire was removed while positioning the distal “J” in the bladder and the proximal “J” in the renal pelvis. The length of the double J stent was calculated in several ways: by measuring the catheter using an external radiopaque ruler placed under the patient, by measuring the length of the guide wire required to reach the bladder, by using an internal radiopaque graduated catheter placed in the ureter (Cook, Inc), or by a formula estimation where stent length (cm) ¼ patient age (y) þ 10 (8). When the distal coil of the double J stent was in the bladder, the wire was withdrawn as the pusher advanced the proximal coil into the renal pelvis, using the radiopaque tip of the pusher as a marker. The decision to place a temporary nephrostomy was at the discretion of the operator (eg, if there was significant bleeding or clot (3) or concern regarding the ability to drain adequately around the double J stent). Retrograde insertions were performed with the patient in the supine position. Retrograde placement was most often performed under direct cystoscopic vision by a urologist. In this study, only placements performed by an interventional radiologist or placements performed as a combined procedure with a urologist were included in the analysis. Retrograde placements by an interventional radiologist via a Mitrofanoff appendicovesicostomy (surgical connection between the skin at the umbilicus and the urinary bladder using the appendix as a conduit) were also included. The technique of “body flossing” was employed in difficult cases. This technique involved a wire advanced from above, through the renal collecting system, snared in the bladder, and exited either via the urethra or a Mitrofanoff appendicovesicostomy. Passage of the wire in the reverse direction was also possible to achieve body flossing. Body flossing provided greater support to the wire in cases of tight strictures, difficult balloon dilation, or facilitated passage of the double J stent over the wire. It was performed either as a combined procedure with a urologist and interventional radiologist or by an interventional radiologist alone.
3
Double J stent exchanges were performed in an anterograde or a retrograde fashion. Anterograde exchanges by the interventional radiologist involved snaring the proximal double J stent in the renal collecting system. If an internal-external nephroureterostomy stent (Salle Intraoperative Pyeloplasty Stent Set; Cook, Inc) was in place, the exchange was facilitated by placing a wire directly through the indwelling stent from above, down into the bladder, over which the double J stent was then placed. These procedures were considered exchanges rather than two-stage insertions because of the preexisting stent in the ureter. Retrograde exchanges performed by the interventional radiologist involved snaring the double J stent from below (the bladder) via the urethra or through a Mitrofanoff appendicovesicostomy using a snare (25 mm) and a directional catheter. Bladder distention was required to open the folds of augmented bladders. The distal tip of the indwelling stent was snared within the bladder and exteriorized about 1 inch. Through the partially exteriorized double J stent, a Glidewire or an Amplatz Super Stiff Guidewire was passed retrograde into the pelvicalyceal system, and the double J stent was removed. A catheter was advanced over the wire to opacify the pelvicalyceal system as a landmark for placement of the new double J stent. The new double J stent was inserted over the guide wire.
Demographics Over an 11-year period, placement of 59 double J stents was attempted during 49 procedures on 35 pediatric patients (26 boys, 9 girls). The mean age of the patients at double J stent placement was 7.3 years (range, 22 d– 18 y; median age, 4 y), and the mean weight was 21.9 kg (range, 2.5–70 kg; median, 16.9 kg). The diagnoses of the 35 patients are shown in Table 2. The most frequent indications for stent placements were the management or prevention of worsening hydronephrosis or hydroureteronephrosis, infection, and exchanges of existing stents. Almost 80% of double J stents were placed in boys (n ¼ 47; 79.7%). Table 2 . Underlying Diagnoses for Double J Stent Insertions
Underlying Diagnoses
No. Patients
No. Double J Stents
Congenital ureteric strictures UPJ obstruction
7 6
19 6
Malignancy
5
11
Metabolic/stone disease Renal transplant
5 4
8 5
Prior posterior urethral valves
3
4
Prior bladder exstrophy Miscellaneous*
2 3
2 4
Note. Several patients had more than one primary diagnosis or indication for drainage. UPJ ¼ ureteropelvic junction. n Neurogenic bladder (n ¼ 1), prune-belly syndrome (n ¼ 1), multicystic dysplastic kidney disease (n ¼ 1).
4
’
Image-Guided Pediatric Ureteric Stent Insertion
Sertic et al
RESULTS Placement of 59 double J stents was attempted, 44 of 59 (75%) insertions and 15 of 49 (25%) exchanges, in 35 patients. Nine patients had multiple stents placed (bilateral insertions [n ¼ 4 of 35; 11%], repeated stent exchanges [n ¼ 2 of 35; 6%], or both [n ¼ 3 of 35; 9%]). Three placements failed (n ¼ 3 of 59; 5%). There were 10 bilateral insertions—20 of 59 double J stents (34%). In one instance, a patient had a duplicated right system, and a double J ureteric stent was inserted into each of the patient’s two right ureters. In 39 procedures (66%), a nephrostomy tube was left in situ. In 13 of 59 (22%) procedures (8 insertions, 5 exchanges), balloon dilation of the ureter was required to place the double J stent. Balloon sizes ranged from 3–6 mm diameter. A summary of stent placement techniques employed is provided in Table 3. Of 44 insertions, 3 (7%) were retrograde; of 15 exchanges, 11 (73%) were anterograde, and 4 (27%) were retrograde (Table 3). An interventional radiologist performed 44 of 59 (75%) double J stent procedures, and an interventional radiologist together with a urologist performed 15 of 59 (25%) double J stent procedures: 9 (60%) insertions (including lithotripsy [n ¼ 4], cystoscopy [n ¼ 2], and retrograde through the urethra [n ¼ 3]) and 6 (40%) exchanges (3 anterograde and 3 retrograde—through the urethra [n ¼ 2] and through a Mitrofanoff appendicostomy [n ¼ 1]). The urologist requested assistance in 9 of the 15 cases because of technical difficulties and inability to perform the exchanges cystoscopically (exact technical difficulty could not be determined retrospectively). Body flossing was employed in three instances. These variations all were performed as combined procedures with a urologist. There were 15 of 59 (25%) combined double J stent procedures performed with a urologist, including lithotripsy (n ¼ 4 of 15; 27%), diagnostic cystoscopy (n ¼ 2 of 15; 13%), exchanges (n ¼ 6 of 15; 40%), and one-stage retrograde insertions (n ¼ 3 of 15; 20%). Multiple concomitant procedures were performed in the same sitting in 45 of 59 (92%) procedures, including 41 nephrostomy tube insertions or exchanges, 13 ureteric dilations, 6 cystoscopies, 3 cystograms, 4 nephrolithotomies (2 laser Table 3 . Summary of Double J Stent Placement Techniques Insertions (n ¼ 44) One-stage
Anterograde (percutaneous) Retrograde (through urethra)
n ¼ 17 n¼3
Two-stage
Through nephrostomy
n ¼ 24
Exchanges (n ¼ 15) Anterograde Percutaneous Through nephrostomy Through nephrouterostomy Retrograde Through urethra
n¼4 n¼2 n¼2
Through Mitrofanoff appendicovesicostomy n ¼ 2
’
JVIR
lithotripsies), 2 pyelograms, 1 abdominal drainage, 1 chest tube insertion, and 1 central venous line insertion. Stent size and length varied according to patient size. Stent sizes ranged from 3.7-F to 8-F (3.7-F, n ¼ 9; 4.7-F, n ¼ 22; 5-F, n ¼ 5; 6-F, n ¼ 14; 8-F, n ¼ 6). The intended stent size was not recorded in the three technical failures (see later on). Stent length ranged from 10–26 cm (10 cm, n ¼ 10; 12 cm, n ¼ 9; 14 cm, n ¼ 6; 16 cm, n ¼ 5; 18 cm, n ¼ 4; 20 cm, n ¼ 3; 22 cm, n ¼ 11; 24 cm, n ¼ 6; 25 cm, n ¼ 1; 26 cm, n ¼ 1). Of 59 attempted stent placements, 56 (95%) were technically successful. Technical failure occurred on two nonconsecutive occasions in a patient with multiple congenital severe ureteric strictures (n ¼ 2). The other technical failure involved an inability to cannulate the ureter in a 54-day-old (3.9-kg) patient with a urinoma secondary to posterior urethral valves—a nephrostomy tube was left instead (n ¼ 1). Of the remaining 56 stents, 53 (95%) were functionally primarily successful, and 3 (5%) were initial functional failures. Two functional failures occurred in a 3.5-kg neonate with hyperoxaluria and ureteric strictures. Both 3.7-F stents were positioned appropriately but proved too small for optimal drainage, resulting in urinary retention and leakage around the patient’s nephrostomy tubes. The stents were replaced with 4.7-F double J stents, which functioned well (secondarily functionally successful). The last functional failure occurred in a patient in whom the double J stent was inserted but because of the small size of the patient’s collecting system, the coil in the upper collecting system did not form properly and subsequently migrated anterograde into the bladder (n ¼ 1). This stent also required replacement. Among the patients in whom a double J stent was successfully placed, the primary functional success was 95% (n ¼ 53 of 56), and the remainder were secondarily functionally successful.
Complications Two complications occurred during the procedure, classified as SIR Minor B (ie, nominal therapy, no consequence) (5). One insertion of a double J ureteric stent caused a small perforation in the ureter and a urine leak with urinoma and associated ileus, which resolved with Foley catheterization (n ¼ 1, Minor B). The other complication involved a patient with multiple complex medical issues who developed an acute pleural effusion with associated lung collapse during a combined lithotripsy procedure. The pleural effusion was thought to be caused by tracking into the chest of the irrigation fluid used during the lithotripsy. Urgent evacuation of the pleural fluid (350 mL of serosanguineous fluid) was required (n ¼ 1, Minor B). Complete reexpansion of the lung followed, with resolution of respiratory compromise and no sequelae. Four complications occurred after the procedure. There was one early complication that involved moderate
Volume XX
’
Number X
’
Month
’
2014
self-limiting hematuria that did not require transfusion. The three late complications included urine leak around nephrostomies from undersized bilateral double J stents, which was resolved by an exchange for larger stents (n ¼ 1); bacteriuria infection with Enterobacter cloacae which required a peripherally inserted central catheter for intravenous antibiotic treatment (n ¼ 1); and Klebsiella oxytoca treated with intravenous and oral antibiotics (n ¼ 1). The stent dwell times were calculated for 50 of the 56 stents successfully placed. Four stent removals were not performed at our institution, and two double J stents in one patient in whom stent placement was palliative treatment were still in place at the time of death. Mean dwell time was 113 days (range, 6–340 d; median, 96 d). A urologist removed 38 double J stents; 35 were removed cystoscopically, and 3 were removed during surgery (pyeloplasty [n ¼ 1], ureterectomy [n ¼ 1], nephroureterectomy [n ¼ 1]). An interventional radiologist removed 12 double J stents (12 of 50; 24%); 7 were removed during stent exchanges, and 5 were removed as a sole procedure. Mean time between double J stent exchanges performed by an interventional radiologist was 111 days (range, 8–305 d; median, 96 d).
DISCUSSION Double J ureteric stents are an effective means to relieve ureteric obstruction, and placement of a double J stent is one of the most common urologic procedures (2). Double J stents increasingly are placed by interventional radiologists (3,6). However, there is little in the literature describing pediatric image-guided ureteric stent placement. Roebuck (6) and Barnacle et al (3) published reviews on pediatric interventional uroradiology. Barnacle et al (3) reported the most common indications for pediatric ureteric intervention below the ureteropelvic junction were congenital or postoperative vesicoureteral obstruction, transplant-related ureteric stricture, and malignant ureteric obstruction. The findings of Barnacle et al (3) are similar to our experience (Table 2). Roebuck (6) commented that stents usually are placed in ureters after balloon dilation. Balloon dilation was employed in only 13 cases in our series, and double J stent placement was successful in all 13 cases. In three instances, balloon dilation enabled a double J stent to be placed successfully after a prior failure without balloon ureteroplasty. The overall 90% technical and functional success rate in the present study is comparable to reports in the current literature. Kljucevsek and Kljucevsek (9) outlined their experiences with percutaneous insertion of ureteric stents in 10 children with ureteral obstruction using an anterograde approach. They concluded that the imageguided percutaneous approach is useful when the endoscopic or retrograde approach is not an option. Our
5
results compare favorably with their 80% initial success rate (8 of 10 on first attempt; 100% success rate with second attempt). Although the anterograde approach of image-guided ureteric stent insertion has been in practice since the 1980s, the retrograde approach is still relatively novel. In 2007, Carrafiello et al (10) described success with fluoroscopically guided retrograde replacement of ureteric stents in adult patients through the urethra. They recommended the fluoroscopic approach when the cystoscopic approach either fails or is suboptimal. Cystoscopy relies on the ability to see through clear urine. Fluoroscopic exchanges have an advantage when it is impossible to see through urine (eg, bloody, mucoid, or cloudy urine from an augmented bladder) as well as the advantage of the smaller caliber of the devices, which are easier to manipulate inside the bladder and consequently involve a lower risk of causing bleeding (10). Other studies reported fluoroscopically guided replacement success rates ranging from 97%–100% (11–15). The retrograde exchanges reported in the present study were similarly successful without any complications. In patients with a Mitrofanoff appendicovesicostomy, cystoscopic visualization of the ureteric orifices may be very difficult because of augmentation, cloudy mucus, and/or the unfavorable angle of access for a rigid cystoscope from the umbilicus. A fluoroscopic exchange using a snare and an angled catheter has significant advantages. Distention of the bladder to efface the mucosal folds of the augmented bladder and the use of an angled catheter for snaring are imperative The main disadvantage is the radiation dose associated with snaring, which is cumulative in a patient who may return for repeat exchanges. The issue of forgotten stents has been discussed in the literature (16–19). The recommended dwell times vary widely in the literature from exchanges at 6 weeks to 6 months, although double J stents can be left in place for 12 months without any issues (6,9,17). It is necessary to have a system in place (as arranged by a urologist or interventional radiologist) to ensure the timely exchange of a patient’s double J stent is not overlooked. Our practice goal is to exchange a double J stent electively at approximately 3 months. The mean dwell time of double J ureteric stents inserted by our department was 113 days (ie, 3.75 mo) (median, 96 d). Characteristic morbidity from symptomatic indwelling ureteric stents includes fever, dysuria, abdominal or flank pain, hematuria, and nocturia (4). Forgotten stents can become encrusted and fragment, causing ureteral obstruction. One study estimated a 6.9-fold increase in cost of care in patients with forgotten stents compared with patients with stents removed in a timely fashion (18). Bacterial colonization of an indwelling stent is common and may be clinically silent. The incidence of bacteriuria and urinary tract infection found in this group is likely an underestimate. Ben-Meir et al (20)
6
’
Image-Guided Pediatric Ureteric Stent Insertion
found there was no statistically significant correlation between rates of stent colonization and symptomatic urinary tract infection in children. They reported a 9.8% rate of subsequent urinary tract infection in their population (20), comparable to our rate of 8.9% (3 of 56). Enterococcus was found to be the most frequent pathogen, whereas Enterobacter species were the responsible pathogens in only 2.4% of cases (20). Yeniyol et al (21) also studied the rates of bacterial infection associated with double J stents and found Escherichia coli to be the most common pathogen, followed by Klebsiella. The difference in results between the most frequent bacterial colonizations (Enterobacter and Klebsiella) in the present study and the colonizations reported in the literature is likely due to the small number of confirmed infections in our small patient population. Hybrid rooms provide significant advantages for urologic procedures and facilitate multidisciplinary collaboration. Concurrent and combined procedures can be more readily accommodated in hybrid rooms in an anticipated planned manner for complex cases or in unplanned cases when one clinician experiences unexpected difficulties during a procedure. For example, when a two-stage anterograde insertion of a double J stent initially failed, a urologist was present and able to assist in a successful retrograde insertion, avoiding the need to abandon the procedure, reschedule it, and undergo a repeated general anesthetic for the patient. Conversely, in four cases when a urologist was unable to insert a ureteric stent, an interventional radiologist was able to insert a stent in three of the four cases. The immediate management of the child with acute pleural effusion and pulmonary collapse was also facilitated by the availability of ultrasound, fluoroscopy, and the expertise of the interventional radiologist to place a pleural catheter expeditiously. In this series of double J stents, 45 concurrent procedures were performed during the double J stent procedures. The collaboration between services in a hybrid room is important in a multidisciplinary approach to patient-centered care. The advantages far outweigh the logistical difficulties of bookings and case planning. The present study has several limitations, including that it was a retrospective review of a limited number of patients from a single institution. The wide range of pathologies; different approaches employed; the variety of devices, wires, catheters, and balloons used; and the unique challenges encountered in many of the individual cases are difficult to capture in a retrospective review such as this. The specific technical difficulties encountered in any one case that prompted the assistance of an interventional radiologist or urologist were not always clearly documented and could not be identified retrospectively. All insertions were performed by dedicated pediatric interventional radiologists in a tertiary care pediatric center. The collaboration with
Sertic et al
’
JVIR
urologists was an important additional factor in achieving the high success rate in more complex cases. Although the study includes a relatively large number of procedures, the number of individual patients is not large enough to determine statistically risk factors for complications of ureteric stent insertions. The full range of symptoms associated with double J stents may have been underreported because some children were too young or nonverbal, potentially resulting in an underestimate of their symptoms. Given the long time span of the study, some patients were lost to follow-up. Only a small number of patients had double J stents inserted in a retrograde fashion during the period of this review, and the outcomes of this technique cannot be comprehensively examined in this study. In conclusion, image-guided insertion of double J ureteric stents in children through an anterograde or a retrograde approach is an effective means for managing ureteric obstruction with a good success rate and an acceptable complication rate. In complex cases, various approaches may be required to achieve success. Access to hybrid rooms for performance of these types of procedures may be helpful.
REFERENCES 1. Mandell VS, Mandell MJ, Gaisie G. Pediatric urologic radiology. Intervention and endourology. Urol Clin North Am 1985; 12:151–168. 2. Mendez-Probst CE, Fernandez A, Denstedt JD. Current status of ureteral stent technologies: comfort and antimicrobial resistance. Curr Urol Rep 2010; 11:67–73. 3. Barnacle AM, Wilkinson AG, Roebuck DJ. Paediatric interventional uroradiology. Cardiovasc Intervent Radiol 2011; 34:227–240. 4. Richter S, Ringel A, Shalev M, Nissenkorn I. The indwelling ureteric stent: a ‘friendly’ procedure with unfriendly high morbidity. BJU Int 2000; 85:408–411. 5. Sacks D, McClenny TE, Cardella JF, Lewis CA. Society of Interventional Radiology clinical practice guidelines. J Vasc Interv Radiol 2003; 14(9 Pt 2): S199–S202. 6. Roebuck DJ. Genitourinary intervention in children. Pediatr Radiol 2011; 41:17–26. 7. Koral K, Saker MC, Morello FP, Rigsby CK, Donaldson JS. Conventional versus modified technique for percutaneous nephrostomy in newborns and young infants. J Vasc Interv Radiol 2003; 14:113–116. 8. Palmer JS, Palmer LS. A simple and reliable formula for determining the proper JJ stent length in the pediatric patient: age þ 10. Urol 2007; 70: 264. 9. Kljucevsek D, Kljucevsek T. Percutaneous insertion of double-J ureteral stent in children with ureteral obstruction: our experiences. J Pediatr Urol 2013; 9:188–192. 10. Carrafiello G, Lagana D, Mangini M, et al. Fluoroscopically guided retrograde replacement of ureteral stents. Radiol Med 2007; 112: 821–825. 11. White PG, Evans C. Minimally invasive removal of retained ureteric stents. Br J Urol 1990; 66:328. 12. Ellis JH, Brodeur FJ Jr, Marx MV, Sheffner SE. Superelastic guide-wire snare for removal of foreign bodies from the urinary tract. Radiology 1992; 183:871–873. 13. de Baere T, Denys A, Pappas P, Challier E, Roche A. Ureteral stents: exchange under fluoroscopic control as an effective alternative to cystoscopy. Radiology 1994; 190:887–889. 14. Boardman P, Cowan NC. Technical report: fluoroscopically guided retrograde ureteric stent retrieval and replacement using a guide catheter directed snare. Clin Radiol 1997; 52:308–309.
Volume XX
’
Number X
’
Month
’
2014
15. Wetton CW, Gedroyc WM. Retrograde radiological retrieval and replacement of double-J ureteric stents. Clin Radiol 1995; 50:562–565. 16. Singh I. Indwelling JJ ureteral stents—a current perspective and review of literature. Indian J Surg 2003; 65:405–412. 17. Fishman JR, Presto AJ 3rd. The forgotten ureteral stent. West J Med 1994; 160:569–570. 18. Sancaktutar AA, Sö ylemez H, Bozkurt Y, Penbegül N, Atar M. Treatment of forgotten ureteral stents: how much does it really cost? A costeffectiveness study in 27 patients. Urol Res 2012; 40:317–325.
7
19. Singh V, Srinivastava A, Kapoor R, Kumar A. Can the complicated forgotten indwelling ureteric stents be lethal? Int Urol Nephrol 2005; 37: 541–546 20. Ben-Meir D, Golan S, Ehrlich Y, Livne PM. Characteristics and clinical significance of bacterial colonization of ureteral double-J stents in children. J Pediatr Urol 2009; 5:355–358. 21. Yeniyol CO, Tuna A, Yener H, Zeyrek N, Tilki A, Coskuner A. Bacterial colonization of double J stents and bacteriuria frequency. Int Urol Nephrol 2002; 34:199–202.
