Effects of Peritonsillar Infiltration with Bupivacaine and Oral Dextromethorphan on Post-Tonsillectomy Pain

Jung, Dae Gun; Park, So Young; Park, Hae Seop; Lee, Shi Hyung; Lim, Phil Kyu; Cho, Ju Eun

Abstract

BACKGROUND AND OBJECTIVES: Peripheral tissue or nerve injury often leads to post-injury pain hypersensitivity caused by peripheral and central sensitization. Central sensitization which plays a significant role is triggered by nociceptive afferent inputs and mainly results from N-methyl-D-aspartic acid (NMDA) receptor activation. If the afferent impulses are prevented from gaining access to the CNS or if NMDA receptor is blocked by antagonist, central sensitization will not develop and then less pain will result. Previous studies demonstrated that preoperative infiltration of local anesthetics or oral NMDA receptor antagonist could alleviate postoperative pain. We investigated the effects of peritonsillar infiltration with bupivacaine and oral dextromethorphan on post-tonsillectomy pain.
MATERIALS AND METHODS
Forty consecutive patients were randomly allocated to one of four groups. Group I was bupivacaine-treated group, and group II was dextromethorphan-treated group. Group III was both bupivacaine and dextromethorphan-treated group, and group IV was control group. Pain scores were assessed using self-rating numeric rating scale ( NRS) at rest and on swallowing during the postoperative day 0, 1, 2, and 7. Doses of supplementary diclofenac administered postoperatively were also recorded.
RESULTS
Group I, II, and III showed significantly lower NRS pain scores compared with control group at rest and on swallowing throughout the postoperative 7 days. Diclofenac doses were not statistically different among the four groups.
CONCLUSION
Preoperative peritonsillar infiltration with bupivacaine and/or medication with dextromethorphan contributed to decrease the intensity of postoperative pain after tonsillectomy.