Randomised Control Study to Assess the Effect of Methylene Blue and Lignocaine as Analgesic in Perianal Surgery in M.Y. Hospital

Abstract

Srashti Shah*, Ankur Maheshwari and Avinash Gautam

Background: Perianal surgeries have been associated with considerable postoperative pain and discomfort. Perianal intradermal injection of methylene blue has been shown to ablate perianal nerve endings and bring about temporary pain relief.

Method: A randomized, prospective, single-blind placebo-controlled trial was conducted. Patients were randomized to intradermal injection at perianal surgeries of either 6 ml of 1% methylene blue and 6 ml of 1% lignocaine or 12 ml of 1% lignocaine. Thus, a total of 12 ml was injected into the perianal skin of each patient prior to surgical dissection. Patients were asked to fill in a pain diary with a visual analogue scale. The primary outcome measure was pain score and analgesic use. Secondary outcomes were complications.

Results: There were 25 patients in the methylene blue arm and 25 patients in the placebo arm. There were no statistically significant differences in the sex, type of hemorrhoid, number of hemorrhoids excised, duration of surgery or hospital stay. The mean pain scores were significantly lower and the use of paracetamol was also significantly less in the methylene blue group during the first three postoperative days. Other complication rates were not significantly different.

Conclusion: Perianal intradermal injection of methylene blue was useful in reducing the initial postoperative pain of perianal surgeries.