Relation between pelvic floor neurophysiological abnormalities and erectile dysfunction in patients with obstructed defecation

Abstract
Background
Obstructed defecation is a common pelvic floor medical problem among adult population. Pelvic floor disorders were reported to be associated with sexual dysfunction including erectile dysfunction among male patients. The aim was to determine the relation between pelvic floor neurophysiological abnormalities and erectile dysfunction in male patients with obstructed defecation.

Methods
This cross-sectional study included 65 married male patients with obstructed defecation and a control group consisted of 15 apparently healthy married males. Assessment of obstructed defecation severity was done by using modified obstructed defecation score, time of toileting and Patient Assessment of Constipation-Quality of Life questionnaire. Assessment of erectile functions was done using erectile function domain of International Index of Erectile Function questionnaire and Erectile Dysfunction-Effect on Quality of Life Questionnaire. Anal manometry and dynamic pelvis magnetic resonance imaging were done. Electrophysiological studies included pudendal nerve motor conduction study and needle electromyography of external anal sphincter, puborectalis and bulbocavernosus muscles.

Results
There were 32 patients (49.2%) who had erectile dysfunction. The maximum straining anal pressure was significantly higher among patients with erectile dysfunction. Pudendal nerve terminal motor latency was significantly delayed and the percentage of bilateral pudendal neuropathy was significantly higher among patients with erectile dysfunction. The percentage of electromyography evidence of denervation with chronic reinnervation in the external anal sphincter and bulbocavernosus muscles were significantly higher among patients with erectile dysfunction. Regression analysis detected three co-variables to be associated with significantly increasing the likelihood of development of erectile dysfunction. These were maximum straining anal pressure (odd ratio = 1.122), right pudendal nerve terminal motor latency (odd ratio = 3.755) and left pudendal nerve terminal motor latency (odd ratio = 3.770).

Conclusions
Erectile dysfunction is prevalent among patients with obstructed defecation. It is associated with characteristic pelvic floor electrophysiological abnormalities. Pelvic floor neurophysiological changes vary from minimal to severe neuromuscular abnormalities that usually accompanying erectile dysfunction. Pudendal neuropathy and increased maximum straining anal pressure are essential risk factors for increasing the likelihood of development of erectile dysfunction in patients with obstructed defecation.