Posterior Mesh Fixation at the Levator Ani Level in Apical Pelvic Organ Prolapse

This study is a multicenter, randomized, controlled, evaluator-blinded, non-inferiority clinical trial. The null hypothesis is that colposacropexy with posterior mesh fixation to the vaginal vault (without rectovaginal dissection) is associated with an anatomical and/or functional failure rate that is equal to or more than 15% higher than colposacropexy with posterior mesh fixation to the levator ani muscle (deep rectovaginal dissection). A non-inferiority margin of 15% has been selected because smaller differences are not considered clinically relevant.

With this project, the investigators aim to evaluate the outcomes of a simplified colposacropexy technique that avoids dissection of the rectovaginal space and deep pelvic mesh fixation. Demonstrating non-inferiority would imply rejecting the null hypothesis.

The procedure is indicated for women with stage II-IV uterine or vault prolapse according to the POP-Q classification, with or without associated anterior and/or posterior vaginal wall defects. The decision to perform surgery will be made by the gynecologists, independent of trial participation, to ensure that study enrollment does not influence standard surgical indications. Exclusion criteria include previous abdominal or vaginal mesh prolapse reconstructive surgery or POP-Q stage I or asymptomatic prolapse.

Sample size calculations assume a 91% success rate for the standardized procedure (Lee 2014), a non-inferiority margin of 15%, a 95% confidence interval, and 80% statistical power. A total of 166 patients (83 per group) are required, accounting for a 10% dropout rate.

DESCRIPTION OF THE SURGICAL TECHNIQUE

The vesicovaginal dissection and exposure of the sacral promontory will be performed identically in both groups. A predesigned polypropylene mesh will be used, consisting of:

• an apical end for fixation to the sacral promontory,
• two lateral arms shaped like "butterfly wings" to cover and support the anterior and lateral vaginal walls,
• and two lower arms designed for fixation to the levator ani muscle.

Fixation of the mesh to the vagina, sacral promontory, and (when applicable) the levator ani muscle will be performed using nitinol helical mechanical sutures (Spire'it). At the vesicovaginal space, the mesh will be anchored at the anatomical depth corresponding to the vesical neck level in both groups.

The only difference between groups involves the posterior compartment dissection and mesh fixation:

• Group A (standard technique): the posterior arms of the mesh are anchored bilaterally to the levator ani muscle with mechanical sutures.
• Group B (simplified technique): the posterior arms are removed, and the mesh is anchored only to the vaginal vault or cervix with mechanical sutures, without rectovaginal dissection.

Inclusion criteria

• Women with primary or recurrent apical prolapse (uterine or vaginal vault) stage II-IV according to the POP-Q classification.
• Women with symptomatic POP with indication of reconstructive POP surgery.
• Agreement to comply with all scheduled visits and assessments through 12 months post-surgery.
• Understand and accept the study procedures and sign the informed consent.

Exclusion criteria

• History of abdominal reconstructive surgery for pelvic organ prolapse.
• History of vaginal reconstructive surgery for prolapse using mesh.
• Stage I prolapse according to the POP-Q classification, or asymptomatic prolapse.
• Medical contraindication to general anesthesia.
• Patient preference for vaginal surgical treatment.
• Declines participation in the study.
• Patients with disabilities or unable to understand the terms of the study.