The clinical value of magnetic resonance defecography in males with obstructed defecation syndrome.

BACKGROUND: The aim of the present study was to assess the relationship between symptoms of obstructed defecation and findings on magnetic resonance (MR) defecography in males with obstructed defecation syndrome (ODS).
METHODS: Thirty-six males with ODS who underwent MR defecography at our institution between March 2013 and February 2016 were asked in a telephone interview about their symptoms and subsequent treatment, either medical or surgical. Patients were divided into 2 groups, one with anismus (Group 1) and one with prolapse without anismus (Group 2). The interaction between ODS type and symptoms with MR findings was assessed by multivariate analysis for categorical data using a hierarchical log-linear model. MR imaging findings included lateral and/or posterior rectocele, rectal prolapse, intussusception, ballooning of levator hiatus with impingement of pelvic organs and dyskinetic puborectalis muscle.
RESULTS: There were 21 males with ODS due to anismus (Group 1) and 15 with ODS due to rectal prolapse/intussusception (Group 2). Mean age of the entire group was 53.6 ± 4.1 years (range 18-77 years). Patients in Group 1 were slightly older than those in Group 2 (age peak, sixth decade in 47.6 vs 20.0%, p < 0.05). Symptoms most frequently associated with Group 1 patients included small volume and hard feces (85.0%, p < 0.01), excessive strain at stool (81.0%, p < 0.05), tenesmus and fecaloma formation (57.1 and 42.9%, p < 0.05); symptoms most frequently associated with Group 2 patients included mucous discharge, rectal bleeding and pain (86.7%, p < 0.05), prolonged toilet time (73.3%, p < 0.05), fragmented evacuation with or without digitation (66.7%, p < 0.005). Voiding outflow obstruction was more frequent in Group 1 (19.0 vs 13.3%; p < 0.05), while non-bacterial prostatitis and sexual dysfunction prevailed in Group 2 (26.7 and 46.7%, p < 0.05). At MR defecography, two major categories of findings were detected: a dyskinetic pattern (Type 1), seen in all Group 1 patients, which was characterized by non-relaxing puborectalis muscle, sand-glass configuration of the anorectum, poor emptying rate, limited pelvic floor descent and final residue ≥ 2/3; and a prolapsing pattern (Type 2), seen in all Group 2 patients, which was characterized by rectal prolapse/intussusception, ballooning of the levator hiatus with impingement of the rectal floor and prostatic base, excessive pelvic floor descent and residue ≤ 1/2. Posterolateral outpouching defined as perineal hernia was present in 28.6% of patients in Group 1 and were absent in Group 2. The average levator plate angle on straining differed significantly in the two patterns (21.3° ± 4.1 in Group 1 vs 65.6° ± 8.1 in Group 2; p < 0.05). Responses to the phone interview were obtained from 31 patients (18 of Group 1 and 13 of Group 2, response rate, 86.1%). Patients of Group 1 were always treated without surgery (i.e., biofeedback, dietary regimen, laxatives and/or enemas) which resulted in symptomatic improvement in 12/18 cases (66.6%). Of the patients in Group 2, 2/13 (15.3) underwent surgical repair, consisting of stapled transanal rectal resection (STARR) which resulted in symptom recurrence after 6 months and laparoscopic ventral rectopexy which resulted in symptom improvement. The other 11 patients of Group 2 were treated without surgery with symptoms improvement in 3 (27.3%).
CONCLUSIONS: The appearance of various abnormalities at MR defecography in men with ODS shows 2 distinct patterns which may have potential relevance for treatment planning, whether conservative or surgical.