Study design, materials and methods
A total of 106 patients with POP who underwent POP repair in our hospital were included and retrospectively analyzed. Patients with preoperative OAB, with previous POP surgery or anti incontinence surgery, active urinary infections, bladder tumor or stones were excluded. All patients were performed reinforcement of the anterior vaginal wall using a mesh. In patients with uterine prolapse and large rectcele, mesh was also placed on the posterior vaginal wall. Urologic and gynecologic history, vaginal examination and overactive bladder symptom score (OABSS) were completed all patients. We diagnosed OAB with 2 or more urgency scores and 3 or more total scores . POP was evaluated at pelvic organ prolapse quantification (POP-Q). The presence or absence of paravaginal defect was evaluated by MRI examination while inducing Valsalva. We diagnosed paravaginal defect that the attachment of the vagina to the pelvic sidewalls was removed. Prior to surgery, urodynamics study examination (UDS), urethral pressure profiles (UPP) or abdominal leak point pressure (ALPP) was performed in all cases. The urethral function was evaluated by Q-tip test and stress test with 200 ml of physiological saline injected into the bladder of the patient. The stress test was performed by injecting 200 - 300 ml of saline into the bladder. Postoperative OAB symptoms were obtained by OABSS 12months after operation and mean follow up periods was 42.7 months. We defined improvement of OAB as either complete resolution of frequency and/or urge incontinence, or improvement (decrease urgency score less than 2 and total score less than 3). They were divided into clinically preoperative OAB group (n=47) and non OAB group (n=59). Factors correlated with de novo OAB after POP repair surgery were examined to elucidate the cause of OAB onset in POP patients.
Results
Twenty-six patients (44.7%) were POP stage 1 to 2 and 21 patients (55.3%) were POP stage 3 to 4. Thirty patients (61.2%) had paravaginal defect. Thirty-three patients (70.0%) had a central defect. In all cases, tension-free vaginal mesh surgery (TVM) was performed for the cystocele. In the 14 cases (29.8%), TVM surgery for the posterior vaginal wall was also performed. Only 7 patients (14.9%) underwent concomitant urinary stress incontinence surgery. There was no significant difference in age (68.4±7.9 vs. 71.3±6.5), morbidity of hypertension, diabetes mellitus and BMI between the OAB improvement group and the OAB persistent group. In 47 preoerative OAB patients, OAB symptoms were improved after surgical treatment in 31 cases (65.9%). Thirteen responders (50.0%) with POP stage 1-2 group while eighteen responders (85.7%) with POP stage 3-4 group reported improvement in OAB after POP repair. Twenty five responders (83.3%) with paravaginal defect group while six responders (35.2%) without paravaginal defect group reported improvement in OAB after POP repair. The odds ratio of OAB improvement after surgery, over POP stage 3 was 6.000 (p=0.013, 95%CI 1.416-25.424), and presence of paravaginal defect was 9.167(p=0.001, 95%CI 2.300-36.530).
Interpretation of results
Women with severe POP or para-vaginal defect who undergo surgical repair experienced significant improvement in OAB symptoms after surgery. In high stage POP and para vaginal defect cases, it is conceivable that sympathetic and para-sympathetic nerves on the dorsal side of the bladder are likely to be extended in a wide range. Neuromodulation therapy in OAB targets these nerves. In this study, nerve and detrusor muscle change were improved by surgery and it was considered to be reversible. Therefore, extension of these nerves by POP may affect the onset of OAB. Severe POP or present of para-vaginal defect are considered a predictor of improvement of OAB symptoms after POP surgery.