Surgeon-Scientist National Institute of Health Bethesda, Maryland, United States
Introduction: The primary treatment for non-muscle invasive bladder cancer (NMIBC) is transurethral resection of bladder tumor (TURBT). However, the TURBT procedure’s piecemeal approach presents complications such as the risk of tumor cell dissemination (seeding) to healthy areas, absence of detrusor muscle, prolonged irrigation time, and higher risk of bladder perforation. These issues contribute to higher recurrence rates in TURBT cases.
An alternative to the traditional TURBT is the En-bloc resection of bladder tumors (EBRT). EBRT minimizes the complications associated with TURBT by extracting a tumor in a single cut along with a continuous margin of healthy tissue. Utilizing methods such as polypectomy snares, lasers, needle-shaped electrodes, ERBT has the potential to reduce seeding and, consequently, recurrence rates. Additionally, by striving to preserve the detrusor muscle, EBRT is likely to provide a better understanding of recurrence rates while simultaneously reducing them.
Although EBRT offers several benefits, current techniques face challenges such as the immediate extraction of a resected specimen and controlled depth cuts to prevent bladder wall perforations. To address these issues, a modified TURBT instrument (bipolar resectoscope) has been developed. It includes features such as a large vacuum channel for extraction, a guided cutting path for precision, and a modified bipolar cutting loop for enhanced performance. The present challenge is to optimize all aspects of the new design to ensure high-level functionality and compatibility with both existing OR equipment and user’s needs.
Materials and
Methods: (1) Due to a manufacturer update to the cable connector, the current resectoscope prototype cannot interface the Electrosurgery Unit (ESU) with the electrode. The electrode is responsible for cutting and coagulating tissue; Without connection to the ESU, the resectoscope cannot function as intended. (2) When the electrode is placed inside of the resectoscope, it must be securely attached to ensure proper connection to ESU and maintain the cutting path. The current method involves a fixed connection by soldering metal onto the electrode, which is inconvenient to the user as they cannot easily remove/replace the electrode if needed. (3) The button designed for suctioning resected specimens from the bladder is difficult to press both in terms of feel and placement.
Potential design changes were modeled using the Solidworks CAD software. Selected components were fabricated and tested with 3D printers, enabling practical evaluation and refinement of the designs.
Results, Conclusions, and Discussions: The modifications to the resectoscope design effectively addressed the identified issues. (1) The resectoscope connector interface was adapted to accommodate the new ESU connector, allowing it to fit more securely and ensuring a reliable connection to the electrode and consistent power delivery. (2) To transition from the electrode’s fixed connection to a quick-disconnect system, various design options were explored, including a wedge system and a tapered cone and a mating tapered cavity. Ultimately, the spring-loaded lock-and-key system proved to be the most promising solution. (3) The suction button was upgraded to provide better tactile feedback, and two alternate placements were evaluated based on user preferences. Additional design enhancements for the resectoscope include reducing sheath diameter to less than 9mm for a better fit inside the urethra, integrating a smaller compatible camera, minimizing the size of the back-end mechanism, and facilitating quick loading and unloading of the electrode via the front-end.
