Waterjet aided transurethral dissection of urothelial carcinoma: A prospective clinical study

Introduction & Objectives: Conventional wire-loop transurethral resection of the bladder (TURB) contradicts the basic oncologic principle of resecting tumour en bloc by dissecting through normal tissue. The application of a water jet dissector for mucosal elevation was shown to improve resection of lesions of the gastrointestinal tract. We present the first prospective clinical trial on the application of a combined waterjet dissector and needle-knife in transurethral dissection (TUD) of non muscle-invasive urothelial carcinoma of the bladder (NMIBC). Objective was the evaluation of applicability, efficacy and safety of a transurethral resection of NMIBC by a combined water-jet dissector and needle-knife (HybridKnife®, ERBE Germany). Materials & Methods: Preclinical studies showed that a beam pressure of 30bar and application angles of the water beam of 20-90° to be optimal for the rapid and vigorous elevation of superficial layers of the bladder wall, including mucosa, submucosa and superficial fibres of the detrusor muscle adjacent to the lamina submucosa, known as “bleb-effect”. 30 urothelial carcinomas of the bladder in 17 unselected patients were elevated and dissected with the HybridKnife®. The goal was to determine the safety, effectiveness of resection and overall applicability of the HybridKnife®. Results: No perforation or other complication was seen. All tumours could be dissected from the bladder wall en bloc. TUD of NMIBC by using the HybridKnife® is technically feasible with a steep learning curve seemingly facilitating resection of papillary and solid tumours. Conclusions: The application of the HybridKnife® in TUD of NMIBC is an elegant en bloc dissection technique allowing principles of oncological surgery in transurethral removal of NMIBC. It seems to facilitate histopathologic assessment. A possibly improved oncologic outcome has to be addressed in further studies.