[Neurobiology of postoperative impotence after rectal excision]

The present study was conducted to determine the changes in the neuro-andrologic profile of patients with impotence following rectal ablative surgery.

The study comprised 18 patients who had undergone rectal surgery: abdominoperineal resection of the rectum (AP) in 12 cases (67%), anterior resection of the rectum (AR) in 6 cases (33%). The pharmacologic erection test was negative in 60% of the patients (56% of the AP cases and 67% of the RA cases; differences not significant). Sympathetic lesion was demonstrated in 67% of the patients (50% of the AP cases and 100% of the AR cases; significant difference). Parasympathetic lesion was demonstrated in 38% of the patients (56% of the AP and in none of the RA cases; tendency towards statistical significance). Pudendal lesion was demonstrated in 83% of the patients, although no significant differences concerning pudendal involvement were observed between both types of surgery (92% of the AP group and 67% of the RA group). The frequency of the pudendal lesion was significantly greater than the parasympathetic lesion and the sympathetic lesion tended to be significantly greater than the parasympathetic lesion in patients undergoing ablative rectal surgery. No significant differences were observed between the pudendal and the sympathetic lesion in these patients. No relationship was observed between the type of neurologic lesion and the results of the pharmacologic erection test.

The type of neurological lesion appears to be related with the level of the rectal surgery. The sympathetic innervation would be more frequently compromised in anterior resection of the rectum. The parasympathetic innervation would be more frequently compromised in abdominoperineal resection. The pudendal innervation would be affected by both types of surgical techniques.