Innervation of the rectovaginal wall in patients with rectocele compared to healthy controls

To evaluate if pelvic floor innervation differed in patients with rectocele compared to control subjects and to assess if nerve fiber density of the rectovaginal wall correlated to the clinical presentation of rectocele.

Biopsies from 24 female patients with posterior vaginal wall prolapse stage II (ICS-classification) and rectocele verified at defecography were compared to specimens from age and parity-matched control subjects without posterior vaginal wall prolapse. Nerve fiber density was measured using protein gene product (PGP-9.5) antibodies at immunohistochemistry. Anorectal symptoms were recorded using bowel and anorectal function questionnaires.

The two groups were comparable in age and parity. Mean nerve fiber immunofluorescence intensity was 150.3 +/- 12.5 SD in the patient group compared to 139.3 +/- 8.5 SD in the control group (P < 0.01). Symptoms of anorectal dysfunction were more common in the patient group compared to control subjects (P < 0.01) but there was no difference in anal continence. At logistic regression analysis, nerve fiber immunofluorescence intensity showed no significant correlation to age, menopausal age, parity, body mass index (BMI), prolapse quantification, or any specific self-reported anorectal symptom. Increased nerve fiber immunofluorescence intensity was correlated to increased perineal descent (OR 1.3, 95% CI 1.1-2.1) although not to the size of the rectocele (OR 0.5, 95% CI 0.9-1.2).

Our results show that rectocele may be associated with increased rectovaginal innervation, suggestive of reinnervation of the rectovaginal wall. Nerve fiber density correlated poorly with findings at clinical and radiological examination. Neurochemical characterization of the rectovaginal wall may provide further understanding of the pathogenesis of rectocele.