Endoloop© Closure of the Urinary Bladder is Safe and Efficient in Female Piglets Undergoing Transurethral NOTES Nephrectomy

Abstract

Recently, we showed that various procedures for rigid Natural Orifice Transluminal Endoscopic Surgery (NOTES) can be successfully performed in piglets. However, the safety and effectiveness of endoscopic closure of the urinary bladder remains to be determined before introducing transurethral NOTES in children. Our study was designed to investigate the safety and impermeability of the urinary bladder after endoscopic closure in transurethrally assisted nephrouretectomy in piglets. Five female piglets (mean weight 14.5 kg; range: 14-15) underwent right-sided transurethral nephroureterectomy using a hybrid technique with one 15 mm trocar placed umbilically and one 3 mm trocar placed transvesically. Hilar dissection was performed with a 5 mm Endoligasure vessel sealing device. After umbilical retrieval of the resected kidney, the urinary bladder was closed by an Endoloop via an umbilical "two in one system" with the assistance of a 2 mm transurethrally placed endoscopic clamp. Endpoints of the study were total operation time, duration of cystoscopy and transurethral trocar positioning, duration of nephrectomy, duration of bladder closure and determination of bladder impermeability. Intraoperatively, bladder filling was performed with normal saline (ml), while bursting pressure (mmHg) was measured by filling the harvested bladder with air. All nephroureterectomies were successfully performed with negligible blood loss. Mean total operation time was 46 min (range: 35-69). Cystoscopy and transurethral trocar positioning took 14 min (range: 9-23), and nephrectomy took 28 min (range: 18-48). Mean duration of bladder closure was 4 min (range: 2-6). Mean volume of intraoperative bladder filling was 94 ml (range: 80-100), indicating adequate capacity after closure with Endoloops. Post-mortem bladder impermeability was confirmed by a mean air filling bursting pressure of 88 mmHg (range: 70-140) indicating sufficient bladder closure. A safe urinary bladder closure is mandatory for transurethral rigid NOTES procedures and can be adequately achieved with Endoloops.