Electromyographic assessment of dexamethasone in treatment of post-tonsillectomy pain: Randomized, placebo-controlled trial

Introduction: Surface electromyographic (sEMG) study of post-tonsillectomy swallow-evoked muscular reactions was performed to assess analgesic properties of dexamethasone. Methods: Sixty randomly chosen operated adults were divided into 2 groups. Group 1 (n = 30) was treated with dexamethasone (Dexacort, 20 mg); group 2 (n = 30) was treated with placebo. Pain assessment included visual analogue scale (VAS) pain score and the EMG data such as the timing, electric amplitude and graphic patterns of muscular activity during deglutition. We investigated masseter, infrahyoid and submental-submandibular muscles. Records from trapezius muscle were used for control. The results were compared with previously established normative database. The sEMG data were compared with VAS pain score with regard to changes in clinical condition of the patients. Results: Surface EMG signs of analgesia after tonsillectomy did not always correspond with the VAS pain score. Dexamethasone normalizes muscular activity in deglutition as detected by the EMG records. Statistically significant difference in muscle reactions was detected between the 2 groups. Conclusion: If dexamethasone is administered, the reduction of the postoperative pain could be secondary to the reduction of edema. The sEMG might be used for quantitative evaluation of analgesics via assessment of neuromuscular reactions to analgesia.