A 56-year-old multiparous woman presents with stress urinary incontinence (SUI). Urodynamic studies confirm genuine stress incontinence with a urethral closure pressure of 18 cmH2O (normal >30 cmH2O), indicating intrinsic sphincter deficiency (ISD). Mid-urethral sling (MUS) surgery with retropubic tension-free vaginal tape (TVT) is planned. What is the theoretical mechanism by which TVT corrects SUI based on the integral theory?

• A TVT creates a hammock support at the bladder neck, reinforcing the urethrovesical junction to prevent bladder neck descent
• B TVT compresses the urethra directly, increasing urethral closure pressure by mechanical obstruction
• C TVT reinforces the pubourethral ligaments and anterior vaginal wall under the mid-urethra, creating a 'backboard' that resists kinking/compression of the mid-urethra during increased intra-abdominal pressure ✓
• D TVT anchors to the pubic bone and shortens the urethra, improving sphincteric coaptation

Explanation

The integral theory (Petros and Ulmsten) proposes that stress urinary incontinence results from laxity of the pubourethral ligaments and anterior vaginal wall, which normally act as a rigid backboard allowing the puborectalis to compress the mid-urethra. The TVT tape is placed tension-free under the mid-urethra (not the bladder neck), reinforcing the pubourethral ligament complex and anterior vaginal wall. During increased intra-abdominal pressure (cough, sneeze), the pubococcygeus contracts and kinks the mid-urethra against the tape backboard, preventing urinary leakage. This hammock mechanism of mid-urethral support is different from the older Burch colposuspension which primarily supported the bladder neck. TVT requires no tension at rest and uses the patient's own collagen-rich tissue response to the tape for long-term cure.

Reference: Shaw's Textbook of Gynaecology, 17th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.