Background Methylene blue injection as a long-acting analgesic is widely used in anorectal diseases. However, there are few clinical studies on the effect of methylene blue injection on postoperative pain and anal function of anal fistulectomy in elderly patients.
Objective To observe the effect of methylene blue injection with two different concentrations on postoperative pain of anal fistulectomy in elderly patients.
Methods From March 2012 to December 2020, 80 elderly patients over sixty years old with anal fistulectomy were divided into two groups by random number method. Patients in the two groups were respectively injected with 0.1% and 0.05% methylene blue injection. Postoperative pain (NRS), anal bulge, wound-edge edema at different time points, uroschesis, wound healing time, copracrasia (Wexner score) and other adverse reactions were observed and compared between the two groups.
Results The Wexner score of 0.05% methylene blue injection group was lower than that of 0.1% methylene blue injection group at 1 month after surgery, and the difference between the two groups was statistically significant (MdIQR: 2.002.00, 3.00 vs 3.002.00, 4.00, P=0.009). There was no significant difference in Wexner score between the two groups at 3 months after surgery (P ＞ 0.05). No significant difference was found in the score of NRS, anal bulge, wound-edge edema, at the 1st day, the 3rd day, the 7th day after surgery as well as in the score of uroschesis, wound healing time or other adverse reactions between the two groups (all P＞0.05).
Conclusion 0.1% methylene blue injection and 0.05% methylene blue injection are equivalent to postoperative pain of anal fistulectomy in elderly patients. However, 0.05% methylene blue injection has less effect on anal function and lower risk of copracrasia.
DownLoad: