Why is a sleeve of mucosa left behind just proximal to the verumontanum (veru) in Transurethral Resection of the Prostate (TURP)?

Why a Sleeve of Mucosa is Left Behind Proximal to the Verumontanum in TURP

In TURP, a sleeve of mucosa is left behind just proximal to the verumontanum to preserve urinary continence by protecting the external urethral sphincter from damage during the procedure.

Anatomical and Functional Importance

• The area just proximal to the verumontanum contains the distal urethral sphincter, which is critical for maintaining urinary continence after prostate surgery 1
• Resection too close to this area can damage the sphincter mechanism, leading to post-operative urinary incontinence, which occurs in approximately 1% of TURP procedures 1
• The external sphincter is the primary continence mechanism after TURP, as the procedure removes the internal sphincter (bladder neck) 1, 2

Technical Considerations During TURP

• During TURP, surgeons deliberately preserve a rim of prostatic tissue around the verumontanum to avoid damage to the sphincter mechanism 1
• When performing resection near the apex of the prostate, careful attention must be paid to avoid injury to the sphincter, which could lead to permanent incontinence 2
• The preserved mucosal sleeve serves as a buffer zone between the resection area and the critical sphincter structures 1, 3

Consequences of Sphincter Damage

• Damage to the distal sphincter during TURP can lead to:
  • Permanent stress urinary incontinence (rare but devastating complication, <0.5% of cases) 2
  • Early urge incontinence (more common, occurring in 30-40% of patients) 2
  • Need for artificial urinary sphincter placement in severe cases 4

Risk Factors for Sphincter Injury

• Aggressive resection near the verumontanum 3, 5
• Urethral mucosa rupture during the procedure (increases risk of stricture by OR=2.44) 6
• Lower resection speed (OR=0.48), which may indicate difficult anatomy or less experienced surgeons 6
• Continuous postoperative infection (OR=1.49), which can compromise healing 6

Complications Related to Apical Resection

• Urethral strictures occur in 2.2-9.8% of TURP cases, with higher risk when resection extends too close to the sphincter area 2
• Post-TURP sphincter urethral strictures are particularly challenging to repair while preserving continence 3
• Strictures near the membranous urethra and distal sphincter require specialized surgical techniques to repair while maintaining continence 3, 5

Surgical Technique Considerations

• When performing TURP, the resection should stop at the verumontanum to avoid sphincter injury 1
• For patients who later develop strictures in the sphincter area, specialized urethroplasty techniques are required that preserve the sphincter function 3, 5
• Ventral approach urethroplasty is best suited for repairing strictures close to the membranous urethra to preserve continence 5

Modern Adaptations

• Bipolar TURP has a more favorable perioperative safety profile than monopolar TURP but still requires the same anatomical considerations regarding sphincter preservation 7
• Alternative techniques like laser prostatectomy follow similar principles of sphincter preservation 1

By preserving this mucosal sleeve, surgeons significantly reduce the risk of one of the most devastating complications of TURP—urinary incontinence—while still effectively treating benign prostatic hyperplasia.