The relationship of defecation symptoms and posterior vaginal wall prolapse in women undergoing pelvic organ prolapse surgery.

Background: Defecation symptoms are common among women with pelvic organ prolapse. However, the relationship between posterior vaginal wall prolapse and defecation symptoms remains debatable. Even though there is a plausible biomechanical rationale for posterior wall prolapse to cause obstructed defecation, previous studies have drawn contradictory conclusions regarding the association.

Objective: We aimed to examine the association between posterior vaginal wall prolapse and defecation symptoms by assessing the following: (1) does prevalence of defecation symptoms increase along with posterior wall prolapse severity, (2) is postoperative symptom improvement greater in women who underwent posterior compartment procedures in comparison with those who did not, and (3) is symptom improvement related to the symptom's correlation with the degree of prolapse?

Study Design: We used data from a nationwide longitudinal cohort study with 3515 women undergoing pelvic organ prolapse surgery. We measured the prevalence of 9 defecation symptoms at baseline and at 6 and 24 months after surgery using the short form of the Pelvic Floor Distress Inventory. Baseline degree of prolapse was categorized in stages as defined by the Pelvic Organ Prolapse Quantification System. The relationship between the degree of posterior wall prolapse and prevalence of bothersome defecation symptoms was studied with logistic regression and adjusted for patient characteristics and severity of anterior wall and apical prolapse. Generalized estimating equations were used to assess the longitudinal change in symptom prevalence in groups of participants with and without repair for posterior vaginal compartment. Correlations between symptom improvement and symptom dependency on the degree of prolapse was assessed by calculating Pearson's correlation coefficient.

Results: The stage of posterior wall prolapse (stage 2 vs stage 0) correlated with splinting, straining, incomplete evacuation, fecal incontinence of liquid stool, pain during defecation, fecal urgency, and anorectal prolapse (adjusted odds ratios, 2.7, 2.1, 2.0, 1.5, 2.1, 1.4, and 2.2, respectively; P ≤ .007 for all). Flatal incontinence and fecal incontinence of solid stool were not associated with the severity of posterior vaginal wall prolapse. Obstructed defecation symptoms (splinting, straining, and incomplete evacuation) improved more in women undergoing posterior compartment surgery compared with women undergoing repair for other compartments. The greatest improvement at follow-up was observed for those symptoms that showed strongest association with the degree of prolapse at baseline.

Conclusion: Obstructed defecation symptoms are dependent on the posterior wall anatomy. Women presenting with posterior wall prolapse, and these symptoms can expect to improve after surgery. Other defecation symptoms also improve after pelvic organ prolapse surgery, but they are not as specific to posterior wall anatomy as obstructed defecation symptoms.