Topical Glyceryl Trinitrate Ointment for Pain Related to Anal Hypertonia After Stapled Hemorrhoidopexy

Abstract

Postoperative pain after stapled hemorrhoidopexy is cause for considerable concern and may be related to contracture of continence muscles. We compared glyceryl trinitrate 0.4% ointment with lidocaine chlorohydrate 2.5% gel as topical therapy to relieve the pain of anorectal muscular spasm after stapled hemorrhoidopexy. This was a single-blind, parallel-group, randomized controlled trial. The study was conducted at a university teaching hospital in Rome, Italy. Patients with severe postoperative anal pain after stapled hemorrhoidopexy, clinical evidence of anal hypertonia, and elevated anal resting pressure on manometric assessment were enrolled. Patients treated for concomitant anorectal disease were excluded. Participants were randomly assigned to receive twice-daily, local topical application of glyceryl trinitrate or lidocaine for a total of 14 days. Pain intensity was measured on a visual analog scale at baseline and after 2, 7, and 14 days of therapy. Anal resting pressure was measured pre- and postoperatively and after 14 days of therapy. Of 480 patients undergoing stapled hemorrhoidopexy, 121 had severe postoperative pain (score >3) and underwent clinical examination; 45 patients (13 women, 28 men) had clinically evident anal hypertonia and underwent anorectal manometry; 41 patients had elevated anal resting pressure and entered the study. Mean pain scores were significantly lower with glyceryl trinitrate than with lidocaine on day 2 (2.5 ± 1.0 vs 4.0 ± 1.1, p < 0.0001); day 7 (1.4 vs 2.8, p < 0.0001); and day 14 (0.4 vs 1.4, p = 0.003). Anal resting pressure was significantly lower with glyceryl trinitrate than with lidocaine on day 14 (75.4 ± 7.4 mmHg vs 85.6 ± 7.9 mmHg, p < 0.0001). GTN-induced reduction in sphincter tone could not be evaluated during the initial period, when pain was most intense. Because anorectal manometry was performed only in patients with severe pain and clinical evidence of anal hypertonia, firm conclusions cannot be drawn as to frequency of hypertonia after SH. Bias may have been introduced because the surgical team could not be blinded. Topical 0.4% glyceryl trinitrate is effective in relieving pain and reducing anal resting pressure in patients with anal hypertonia after stapled hemorrhoidopexy.