What instrument is used prior to the insertion of the resectoscope in a TURP procedure?

The instrument used prior to the insertion of the resectoscope in a Transurethral Resection of the Prostate (TURP) procedure is the Van Buren sound. This instrument is designed to assess and dilate the urethra, allowing for easier passage of the resectoscope. The Van Buren sound is a type of urethral sound that helps in determining the size and patency of the urethra, ensuring that the subsequent insertion of the resectoscope can be performed smoothly and safely.

This step is crucial in the preparation for TURP, as an adequately dilated urethra minimizes the risk of trauma and complications during the resection process. The use of sounds is a standard practice in urology to facilitate procedures that involve instrumentation through the urethra. Other instruments listed, such as urethral dilators, scalpel, and forceps, serve different roles in the surgical process but are not specifically used for this preparatory task.