Dynamic Magnetic Resonance Imaging in Surgical Planning of Pelvic Organ Prolapse

Objectives: Up to one-third of women with pelvic organ prolapse (POP) have concomitant rectal prolapse that often manifests as defecatory dysfunction. Dynamic magnetic resonance imaging (dMRI) of the pelvis provides both anatomic and functional information that can be used in conjunction with a physical examination for treatment planning such as combined urogynecologic and colorectal surgery. This study aims to correlate physical exam findings with dMRI interpretation and assess dMRI's role in treatment management of POP.

Methods: Patients who underwent pelvic dMRI ordered by gynecologists, urologists, and urogynecologists from January 2016 to March 2020 were identified in the electronic medical record. The most common reasons for ordering dMRI were defecatory dysfunction (including fecal incontinence and constipation) and prolapse. Patient data reviewed included body mass index (BMI), parity, mode of delivery, smoking history, history of hysterectomy, and prolapse stage. (Table 1). Pre-imaging pelvic physical exam findings were compared to dMRI reports. Surgical planning before and after dMRI was reviewed. Patients were grouped by surgical status following dMRI and the two groups were compared with equal variance T-test, Fischer exact test, and Wilcoxon rank-sum test, depending on the variable analyzed. Kappa was calculated to compare dMRI and physical exam findings.

Results: Sixty-four patients underwent dMRI during the study period. Of those, 57 (89%) patients were eligible for analysis. Eight patients were excluded due to incomplete documentation regarding surgical prolapse management. Patients were primarily Caucasian (n=49, 86%) and mean age was 61.7 years (range 31-87). There was no significant difference in age, BMI, parity, mode of delivery, smoking history, history of prior hysterectomy, or prolapse stage between patients who did and did not have surgery following dMRI. There was also no significant difference noted between the aforementioned groups when evaluating for presence of anterior, posterior, or apical prolapse noted on dMRI. Of patients who did not have prolapse surgery following dMRI, surgery was considered prior to imaging in 12 (57%) of patients. Of patients who did have prolapse surgery following imaging, surgery was considered in 28 (78%) patients prior to imaging (p=0.14). When comparing physical exam findings to dMRI results, 19 (52%) patients had anterior prolapse on physical exam, 30 (81%) had posterior prolapse, and 19 (59%) had apical prolapse, compared to dMRI results reporting 42 (76%), 45 (82%), and 12 (23%) respectively (kappa=0.33, [CI 0.08,0.59], kappa=0.11 [CI -0.24, 0.47], and kappa=0.02 [CI -0.22,0.26]). Significant bowel findings including enterocele, rectal prolapse, patulous anal canal, and incomplete evacuation were noted on 35% (n=19) dMRIs. Of patients who subsequently underwent surgery, 8 (24%) underwent concurrent rectopexy with Colorectal surgery (Table 2).

Conclusions: These findings highlight the utility of dMRI in conjunction with physical examination for surgical planning for patients with POP and defecatory dysfunction.