Retrieval of proximally migrated double J ureteric stents in children using goose neck snare.

PURPOSE: Proximal migration of the ureteric double J stent is a rare but known complication. We describe three cases where a minimally invasive technique for retrieval of displaced double J stents using Amplatz(™) goose-neck snare was successful.
MATERIALS AND METHODS: A retrospective review of patients with displaced double J stent was carried out, in whom cystoscopy guided retrieval of double J stent was attempted with the help of Amplatz goose-neck snare under radiological control.
RESULTS: All three patients were under the age of 3 years. Two patients had migrated double J stent following pyeloplasty and in one patient the double J stent was displaced during a retrograde insertion of double J stent. In all cases, retrieval of displaced double J stent was successfully achieved using Amplatz goose-neck snare. There were no postoperative complications.
CONCLUSION: Our method of retrieval of stent from renal pelvis is simple, safe and minimally invasive. This technique is a useful and safe alternative option for retrieval of proximally migrated double J stents in children.

INTRODUCTION

Insertion of double J (JJ) stent is common in pediatric urology practice. Complications of ureteric stents include stone formation, encrustation, fragmentation of stent, fistula and migration of stent. Proximal migration of the ureteric stent is a rare but a known complication.[12] Various methods of retrieval of stent have been described in adults,[2-5] but these are technically more challenging in children and infants due to the small anatomical caliber. We describe a series of three patients under the age of 3 years, where we demonstrate a minimally invasive technique for retrieval of displaced double J stent using Amplatz™ goose-neck snare under radiological control.

MATERIALS AND METHODS

A retrospective review over a period of 5 years from 2000 to 2005 at our institution was carried out to identify proximal migration of double J stents in pediatric patients. A total of three patients were identified and Amplatz goose-neck snare under radiological control was used to retrieve the proximally migrated double J stents in all the three cases.

Equipment

An 8-F 30° cystoscope was used for the retrieval of double J stents in all the three patients. Amplatz goose-neck snare of appropriate size was used with the help of a 0.035 guide wire. Standard fluoroscopy machine that allowed screening, Digital Subtraction Angiography (DSA) and road map facilities were used for all the three procedures. The radiation dose, whilst not measured exactly in each individual patient, was minimal, involving screening for a minute or two in total, and a single radiograph was taken for records.

Technique

The patient is positioned as for cystoscopy under general anesthesia and an 8-F 30° cystoscope is introduced into the bladder. A 0.035 guide wire is introduced via the cystoscope into the appropriate ureteric orifice and the position checked with fluoroscopy. The cystoscope is removed and replaced by a catheter that comes with the Amplatz goose-neck snare. The catheter is placed adjacent to the double J stent and an appropriate size Amplatz goose-neck snare is introduced through the catheter under fluoroscopy control. The snare is then pushed against the stent and deployed and twisted in order to engage the double J stent. Once the snare is engaged with the stent, the catheter along with the snare and the held double J stent are removed urethrally whilst screening, confirming that the engagement is maintained all the time [Figure 1].

Figure 1

(a) Dislodged stent and Amplatz goose-neck snare in dilated renal pelvis. (b) The Amplatz goose-neck snare is deployed to retrieve the dislodged stent

RESULTS

There were three pediatric patients. It is our practice to remove the ureteric stent 8 weeks following pyeloplasty via a cystoscope. In two cases, migration of double J stent was noted at the time of cystoscopy for elective removal of the stent following pyeloplasty. In one of these two cases, ureteroscopy and stent retrieval was attempted at the time of detection of stent migration, however, without success. In the third case, the patient had a pyeloplasty 2 years back and underwent a retrograde insertion of the double J stent for persistent hydronephrosis. The stent was displaced proximally during retrograde insertion of double J stent. In all the three cases, an Amplatz goose-neck snare under radiological control was used to retrieve the proximally migrated double J stents. The patient characteristics are displayed in Table 1. There were no postoperative complications noted. The average total time of procedure spent under general anesthesia in the operating room was 20 minutes.

Table 1

Case features

DISCUSSION

Dislodgement and migration of double J ureteric stents are rare but known complications. Distally migrated stents into the urinary bladder can be easily removed using forceps with cystoscopy guidance. However, the difficulty arises when the stent migrates proximally. In a comparison study, the stent-to-ureter length ratio was lower in the migrated than in the non-migrated group of patients with ureteric stents, suggesting that shorter ureteric stents predisposed stent migration proximally. The incidence of ureteric stents migrating proximally is quoted as 2%.[2] A shorter than ideal stent, inadequate distal curl and a proximal curl in the upper calyx appear to be significant factors in the process of stent migration.[6]

It is important to reposition or remove a proximally migrated stent as it may cause obstruction or poor drainage to the urinary flow. This can be achieved either by an invasive procedure opening the renal pelvis or via less invasive methods. Numerous methods of retrieval of ureteric stents have been described in the literature. Among these methods, ureteroscopy with the use of grasping forceps, helical basket and ureteral balloon dilator tip have been described in adults.[3-5] In a study on 37 adult patients, ureteroscopy has been used to retrieve the stents with a 91.9% success rate and no complications.[7] Although flexible ureteroscopy has been shown to be a safe and effective modality in the treatment of upper ureteral calculi, with a 90% success rate in children,[8] use of flexible ureteroscopy for stent retrieval in children is yet to be reported. Ureteroscopy and retrieval of proximal stent might be feasible in children, but it may be difficult in young children and infants due to the small anatomical caliber of the ureter.

Fluoroscopy guided retrieval of proximally migrated ureteric stents is an alternative option to ureteroscopy. Under fluoroscopic guidance, an antegrade approach for the removal of such stents via pre-existing non-dilated nephrostomy routes has been described.[9] However, most studies in literature have described a retrograde approach.[1011] Use of goose-neck snare under fluoroscopy guidance for migrated stent retrieval is a straightforward, well-tolerated, minimally invasive retrograde technique described in adults.[10] However, our series represents the only study describing the retrieval of stent from renal pelvis in children using Amplatz goose-neck snare.

In our small series of three pediatric patients, the proximally migrated double J ureteric stents were successfully retrieved using the Amplatz goose-neck snare under fluoroscopy guidance. The technique is simple, minimally invasive with minimal radiation exposure. The patients in our series were very young at 2, 8 and 30 months of age, and in our experience, ureteroscopic retrieval of migrated double J stent in one child was unsuccessful and we attribute this to the small anatomical caliber of ureter in young children. We believe that this technique with Amplatz goose-neck snare is a safe and alternative option for retrieval of proximally migrated double J stents in infants and young children.