Transurethral En Bloc Resection of Bladder Tumor Using an Endoscopic Submucosal Dissection Technique: Preliminary Results in an Animal Model

BACKGROUND Transurethral resection of bladder tumor (TURBT) technique has been considered the routine method for removing most bladder tumors for decades. In contrast, endoscopic submucosal dissection (ESD) is the gold-standard treatment for gastrointestinal superficial tumors. We investigated the effectiveness and applicability of a new technique for en bloc bladder tumor resection using ESD procedure. METHODS Four Landrace Large White Duroc female pigs were anesthetized with isoflurane prior endoscopic resection using a large-caliber prototype fiber bronchoscope. After local infiltration of the submucosa with sodium hyaluronate using an injector needle, a section of the target area (1.0-2.0 cm diameter circular area) was cut with the Dual Knife. RESULTS In total, seven target sections were resected from the pigs. The median size of the resected sections was 1.8 cm (range 1.0-2.5 cm) and the median time taken to perform the resection of one section was 20 min (range 4-35 min). These target sections were completely resected en bloc. Although the small bladder perforations occurred on two occasions, no other short-term complications such as uncontrollable bleeding were observed. CONCLUSION This procedure is a slightly difficult in the pigs with thin bladder walls. However, this procedure with the slim flexible cystoscope may allow us to be able to remove bladder tumors using only light sedation, especially for cases when small tumor recurrence is observed during routine cystoscopy for the patients with non-muscle invasive bladder cancer.