Comparison of Topical Ropivacaine with and Without Ketamine on Post-surgical Pain in Children Undergoing Tonsillectomy: a Randomized Controlled Double-blind Study

Purpose: Tonsillectomy in pediatric patients may cause severe postoperative pain. Topical local anesthetics are an easy and safe way to control post-tonsillectomy pain, but there is no benefit during the early postoperative stage. Topical ketamine shows a good effect on early stage postoperative pain. We compared the effect of topical ropivacaine with and without ketamine on post-tonsillectomy pain.

Methods: Patients aged 3-7 years undergoing tonsillectomy were selected to participate in the study. Our study was performed in a randomized, placebo-controlled, double-blind manner. Patients were randomly assigned to one of two groups using computer-generated random numbers. The researchers who assessed the pain score, the caregivers, and the patient were blinded to group assignment. One group received topical ropivacaine with saline (RS group) and the other group received topical ropivacaine with 20 mg ketamine (RK group) on the tonsillar bed. Pain scores using the modified Children's Hospital of Eastern Ontario Pain Scale (mCHEOPS) at 15 min and 30 min, and at 1, 2, 4, 8, 16 and 24 h were recorded. Rescue analgesic requirement and complications were also recorded.

Results: A total of 66 patients were randomly assigned to the RS group (n = 33) and the RK group (n = 33). The mCHEOPS scores were significantly lower in the RK group at 15 min (P = 0.046). The mCHEOPS scores of the two groups decreased with time, but there was no intergroup interaction. The RS group received more analgesics until 1 h after surgery and the RK group received more analgesics during 1-24 h after surgery. There were no differences in adverse outcomes.

Conclusions: Topical ropivacaine with ketamine can reduce immediate postoperative pain and analgesic requirement better than ropivacaine alone.