Intraoperative cryoanalgesia on reducing post-tonsillectomy pain scales: a meta-analysis of randomized controlled trials.

Objective: To assess the effect of intraoperative cryoanalgesia on subjective pain scores of patients after tonsillectomy.

Methods: A systematic review of PubMED, Web of Science, EMBASE was performed using the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) standards. For the first time, we included and quantitative synthesized English-language randomized controlled trials (RCT) evaluating patients of all age groups with benign pathology who underwent tonsillectomy with intraoperative cryoanalgesia versus without.

Results: A total of 835 publications were identified, and 7 articles with 463 participants met our criteria were selected for meta-analysis. The standard mean difference for overall subjective pain score, subjective pain scores at postoperation Day1 (POD1), POD7 were -1.44 with 95% confidence interval (CI) [-2.17, -0.72], P = .0001; -1.20 with 95% CI [-1.89, -0.50], P = .0007; -0.90 with 95% CI [-1.46, -0.35], P = .001 respectively, both in favor of cryoanalgesia. Nevertheless, subgroup analysis by surgical technique showed no robust effect between hot technique and "relative" hot technique on overall pain: (-1.72, 95% CI [-2.71, -0.73]) vs. (-1.06, 95% CI [-2.20, 0.07]), p=.39; on POD1: (-1.56, 95% CI [-2.78, -0.33]) vs. (-0.97, 95% CI [-1.83, -0.11]), p=.39; and on POD7 (-1.11, 95% CI [-1.81, -0.40]) vs. (-0.89, 95% CI [-2.02, 0.25]), p=.13. The standard mean difference for postoperative secondary bleeding rate was 1.29 with 95% CI 0.37,4.52], p = .06, no difference in 2 groups.

Conclusion: Limited evidence suggests that intraoperative cryoanalgesia during tonsillectomy leads to lower subjective pain score on overall, POD1 and POD7 without differences on post-operation bleeding rate.