The STING in the tale of Teflon®: Delayed ureteric obstruction after subureteric transurethral injection with polytetrafluoroethylene paste for vesicoureteral reflux.

INTRODUCTION: "Subureteric Teflon INGection" (STING) of polytetrafluoroethylene (PTFE/polytef) paste to treat vesicoureteral reflux (VUR) in children was popularised in 1984. It was later abandoned as an implantation material because of the possibility of migration from the injection site. Giant-cell foreign-body granuloma to Polytef in the bladder is a rare cause of ureteric obstruction. Only a handful of cases have been reported in the literature. METHODS: We performed a prospective analysis of a series of 6 adult patients who had childhood STING and presented with foreign-body granuloma to Polytef in the bladder. We report their clinical presentation, findings and treatment. RESULTS: 1 male and 5 females with a history of STING procedure in childhood for VUR presented in later life with foreign-body granuloma to Polytef. The median age at first STING procedure and at presentation to the Urology Department was 3 and 34 years respectively. The most common clinical presentations were flank pain and urinary tract infection (UTI) and all patients had radiological findings of calcified lesions at the vesicoureteric junction(s). 4 patients had histological findings of giant-cell foreign-body granuloma. 4 patients required definitive ureteric reimplantation. CONCLUSION: Polytef granuloma causing distal ureteric obstruction may give rise to significant morbidity and renal damage. Due to the likelihood of progression of the granuloma, excision and ureteric reimplantation is considered the standard approach in the management of patients with viable kidneys. LEVEL OF EVIDENCE: Level 5.

Evaluation of the Impact of Ureteroscope, Access Sheath, and Irrigation System Selection on Intrarenal Pressures in a Porcine Kidney Model.

Introduction: Elevated intrarenal pressure (IRP) during flexible ureterorenoscopy (FURS) is a predictor of postoperative complications. The aim of this study is to evaluate IRP during FURS in a porcine kidney model to determine the safest combination of irrigation device, ureteral access sheath (UAS), and ureteroscope. Methods: Urinary tracts were harvested from Landrace pigs slaughtered for the food chain. Two flexible ureteroscopes, 8.7F and 9.5F, were evaluated. Irrigation systems evaluated included the following: TraxerFlow™ (Rocamed, France), SAPS™ single action pumping system (Boston Scientific), Pathfinder Plus™ (Utah Medical), and a manual "bag squeeze." This experiment was conducted with no UAS, followed by an 11/13F UAS and then a 12/14F UAS. IRPs were measured in the prepared porcine kidney during all possible combinations of scope, UAS, and irrigation system. Results: Pressures were significantly reduced when using 12/14F UAS compared with 11/13F UAS (16.45 ± 5.3 cmH2O vs 32.73 ± 35.66 cmH2O, p = 0.006), and when using 11/13F UAS compared with no UAS (32.73 ± 35.66 cmH2O vs 49.5 ± 29.36 cmH2O, p = 0.02). Pressures were significantly reduced with the 8.7F scope compared with the 9.5F scope (24.1 ± 21.24 cmH2O vs 41.68 ± 34.5 cmH2O, p = 0.001). SAPS generates significantly greater IRP than TraxerFlow, Pathfinder Plus, and a "bag squeeze" (p < 0.05). The most dangerous combination was using the SAPS, no UAS, and larger ureteroscope leading to an IRP of 100.6 ± 16.1 cmH2O. The safest combination was using Pathfinder Plus with a 12/14F UAS and smaller ureteroscope giving an IRP of 11.6 ± 3.65 cmH2O. Conclusion: IRPs are reduced by selecting larger UAS and a small ureteroscope. The SAPS generates significantly higher IRPs than other irrigation systems. To maintain safe IRPs during FURS, urologists should use large UAS, narrow ureteroscopes, and be cautious in the selection of an irrigation device.

Evaluation of a new disposable flexible ureterorenoscope and comparison to an established disposable flexible ureterorenoscope: a prospective, observational study.

PURPOSE: To objectively and subjectively assess the performance and surgical outcomes of the new Innovex EU-scope™ single-use digital flexible ureteroscope (fURS). METHODS: A prospective cohort study was carried out (August 2019 to May 2020). The new single-use fURS (Innovex Medical Devices Co. Shanghai, China) was analysed with regard to visibility, manoeuvrability, laser interference and overall performance using a validated Likert scale. Outcomes are compared to the LithoVue™ (Boston Scientific, Marlborough, MA). RESULTS: One hundred patients were included in this study. 50 cases underwent retrograde fURS using the Innovex EU-scope™ and 50 with the LithoVue™. There were no differences in the patient demographics data, or operative data between the two groups. The Innovex EU-scope™ scored higher visibility scores compared to the LithoVue™, median 4, interquartile range (IQR) (4-4), vs. 3.5, IQR (3-5), p = 0.5086. Both scopes had similar manoeuvrability scores. The Innovex EU-scope™ scored significantly lower with regard to comfort compared to the LithoVue, median 4 IQR (3-4) vs. 4.5 IQR (4-5), p = 0.0445. Whereas, laser interference, affected the Innovex much less than the LithoVue™. Both scopes scored well for overall performance. The median overall performance score for the Innovex was 4 IQR (4-4) vs. 4 IQR (4-5). CONCLUSIONS: This Innovex EU-scope™ has good objective and subjective visibility and manoeuvrability profiles. This single-use flexible ureteroscope may achieve similar clinical outcomes to an established single use instrument.