Role of 0.4 % glyceryl trinitrate ointment after stapled trans-anal rectal resection for obstructed defecation syndrome: a prospective, randomized trial.

Purpose: The anal fissure and spasm represent possible complications and causes of postoperative anal pain in patients that have undergone stapled trans-anal rectal resection (STARR). The etiology of these complications is still questioned such as the treatment modality. This study was designed to evaluate the effectiveness of topical glyceryl trinitrate (GTN) 0.4 % in determining decrease of incidence of postoperative anal spams and fissure and reduction of early postoperative pain.

Methods: From a total of 243 patients referred for obstructed defecation syndrome (ODS) 104 (42.7 %) underwent STARR and were randomized to receive (Group 1) or not (Group 2) topical 0.4 % GTN ointment every 12 h for four postoperative weeks. Postoperative evaluation was made at 1, 6, and 12 months.

Results: At 1 month follow-up, the incidence of anal spasm in Groups 1 and 2 was, respectively, 0 and 14.6 % (6/41) (p = 0.010; Fisher's exact test). The incidence of anal fissure was 4/41 (9.7 %) in Group 2 and 0/44 (0 %) in Group 1 (p = 0.05; Fisher's exact test). Significant differences in median visual analogue scale score between groups were found at 1 week and 1 month follow-up (1; 0-5 vs. 2; 0-7: p = 0.0104; Mann-Whitney U test).

Conclusion: Anal spasm and fissure may represent a cause of early postoperative anal pain in patients that have undergone STARR procedure for ODS. The use of topical GTN 0.4 % ointment in the early postoperative course seems to reduce the incidence of anal spasm and fissure and to improve the associated early postoperative pain.