A Novel Retrieval Technique for Ureteral Stents Under Ultrasound Guidance in Male Patients

Efficacy of the novel, innovative, single-use grasper integrated flexible cystoscope for ureteral stent removal: A systematic review

BACKGROUND

We aimed to define the published impact, efficacy, cost-effectiveness and precise role of the Isiris-α device: the world's first sterile, single-use grasper integrated flexible cystoscope (SUGIFC) for ureteral stent removal.

METHODS

After PROSPERO registration (CRD42021228755), the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines were utilized. The search terms "Grasper Integrated Flexible Cystoscope," and "Isiris," within the following databases: PubMed, Scopus, Cochrane Library, Web of Science and EMBASE were searched.

RESULTS

In this review, a cumulative total experience (10 publications) included 970 "SUGIFC" procedures (755 patients). However, only 366/970 procedures were actually used for "ureteral stent removal," with the remainder being surveillance cystoscopy only (603/970) or foreign body retrieval (1/970). Procedure-related and device failures in planned "removal of ureteral stents," was reported in 8/366 (346 patients) and 1/366 (346 patients), respectively. The cost-benefit utilizing the SUGIFC device is advantageous compared to "in-theatre" stent removals and favours less busy centres where maintenance, repair and replacement costs are more relevant. Other listed benefits include shorter stent indwelling times, shorter procedure duration, lower rates of bacteriuria and urinary tract infections, fewer emergency department visits and lower readmission rates. Technical limitations include the absence of an independent working channel, a narrower visual field and the lack of image universality since the monitor is device-specific.

CONCLUSION

The SUGIFC device needs to be outweighed against local costs and individual health systems. Its application in ambulatory ureteral stent removal may become significant due to the accessibility and convenience that it offers the attending urologist.

Trans-urethral snare stent removal: a novel, self-constructed innovation for simultaneous ureteral stent removal and safety guidewire insertion

BACKGROUND

Ureteral stent insertion and subsequent removal remains one of the most common procedures performed in endourology. We aimed to evaluate a novel, one-step method, permitting simultaneous stent removal and guidewire passage using a self-constructed suture snare via standard cystoscopy. This method should be used prior to ureteroscopy, in cases of minimal stent encrustation and peri-ureteral mucosal oedema, where identification and subsequent cannulation of the ureteral orifice may be a challenge.

METHODS

A self-constructed suture snare is constructed using an open-ended ureteral catheter to facilitate this novel 'Switch' technique. Operative duration, cost feasibility and potential complications with this novel method were assessed in patients with an indwelling stent duration above 100 days.

RESULTS

Age inclusion in this study ranged from 21 to 35 years, with kidney, ureter and bladder scores below 6, in the five patients assessed. Previous ureteral stent indwelling time ranged from 106 to 315 days. Reasons for (pre-stented) ureteroscopy were mostly stone related. The overall recorded procedure time for the Switch technique was successfully performed in less than 96 s (range 68-95 s) in all cases within this series. No procedure-related complications were reported.

CONCLUSION

Utilizing the suture snare, the novel Switch technique was successfully performed in all cases assessed. This method is both time and cost feasible and could be easily utilized in resource-limited areas, regional centres or in cases where a stent grasper is not available, may have malfunctioned or cannot adequately approximate due to distal ureteral stent encrustation.

Quantifying the forces needed for ureteral stent removal: Initial evaluation of magnetic stent removal devices on benchtop and porcine models

BACKGROUND

Indwelling ureteral stents are commonly used in pediatric surgeries for kidney stones and urinary tract obstruction, but often require instrumentation or anesthesia for removal. We evaluated the use of novel magnet devices to remove indwelling ureteral stents with a distally attached magnetic bead. Since the forces required for stent removal are unknown, we aimed to characterize and quantify the forces required for stent removal for future prototype testing.

METHODS

A custom 3-D urinary tract model was used for benchtop testing, and 6 female porcine subjects were used for in vivo testing after obtaining institutional approval. A modified porcine urethral model that patterned the human female urethral anatomy with approximately 4.5 cm urethral length was used. A HF-10 digital force gauge measured the force required to remove stents with varying properties (stent size, presence of curl, and size of distal magnetic bead). These force measurements were compared to the quantified magnetic forces generated by external magnets and catheter tip magnets. Furthermore, the magnetic retrieval devices were tested with various magnetic beads on both benchtop and porcine models.

RESULTS

The required force for removal of a 5 Fr x 14 cm double J stent was significantly higher in the benchtop model compared to the porcine model (4.7N v. 0.8N, p < 0.001). Forces of at least 1N were required from the external magnets to move the stent and bead across a 4-5 cm distance from the bladder neck to the urethral meatus. External magnets at a distance of 4-5 cm produced insufficient forces for removal, and thus they failed to remove the magnetic bead and stent from the bladder. The catheter-based retrieval device showed better success with a variety of different magnet pairs on the retrieval device and stent. Furthermore, the addition of saline to the bladder allowed for better retrieval rates of the smallest beads, even by the smallest magnetic tip catheters.

CONCLUSIONS

The forces required for ureteral stent removal are <1N in the porcine model, and improved benchtop models that emulate such parameters will facilitate future stent removal device testing. Given this threshold, external magnets did not generate sufficient force for stent removal at the required distance of 4-5 cm, whereas catheter tip magnetic retrieval overcomes the minimum distance limitation and showed successful retrieval. While these results are encouraging, further studies will define the optimal combination of catheter magnetic tip size and stent magnetic bead size.