Botulinum toxin vs. topical glyceryl trinitrate ointment for pain control in patients undergoing hemorrhoidectomy: a randomized trial.

PURPOSE: The maximum resting pressure in the anal canal is greatly raised after hemorrhoidectomy. This increase is likely to be the cause of postoperative pain, which is still the most troublesome early problem after hemorrhoidectomy. This study was designed to compare, after hemorrhoidectomy, the effects of intrasphincter injection of botulinum toxin vs. application of glyceryl trinitrate ointment in improving wound heating and reducing postoperative pain at rest or during defecation. METHODS: Thirty patients with hemorrhoids of third and fourth degree were included in the study and randomized in two groups. Anorectal manometry was performed preoperatively and 5 and 40 days after hemorrhoidectomy. One group received one injection containing 20 IU of botulinum toxin, whereas the other an application of 300 mg of 0.2 percent glyceryl trinitrate ointment three times daily for 30 days. RESULTS: Five days after hemorrhoidectomy, maximum resting pressure was significantly reduced compared with baseline values in both groups (85 +/- 15 vs. 68 +/- 11 mmHg for the group treated with botulinum toxin, 87 +/- 11 vs. 78 +/- 11 mniHg for the group treated with glyceryl trinitrate ointment). Overall analysis of postoperative pain at rest showed a significant reduction in the botulinum toxin group vs. glyceryl trinitrate group, whereas pain during defecation and time of healing were similar. Adverse effects, such as headaches, were observed only in the glyceryl trinitrate group. Forty days after hemorrhoidectomy in the glyceryl trinitrate group, maximum resting pressure values were similar to preoperative ones, whereas the values were still reduced in the botulinum toxin group. CONCLUSIONS: A single intrasphincter injection of botulinum toxin was more effective and safer than repeated applications of glyceryl trinitrate in reducing early postoperative pain at rest but not during defecation.