Efficacy of Local Anesthetic Wound Infiltration in Temporomandibular Joint Ankylosis Surgery for Control of Postoperative Pain: A Prospective, Randomized Controlled, and Double-Blinded Trial

Abstract

This study aimed to compare the analgesic efficacy of wound infiltration with ropivacaine alone or with adjuvants clonidine or dexamethasone for postoperative pain in temporomandibular joint ankylosis (TMJA) surgery. The investigators implemented a randomized controlled trial with 3 parallel groups, among the patients of bilateral TMJA visiting the maxillofacial surgery unit between March 12, 2015 and February 5, 2017. At the completion of surgery, wound infiltration was done with 0.25% of ropivacaine (R group), 0.25% of ropivacaine with 0.5 mcg/kg of clonidine (RC group), 0.25% of ropivacaine with 0.1mg/kg of dexamethasone (RD group), and 0.2mL/kg of drug volume on each side. The primary outcome variables were total opioid consumption (fentanyl in micrograms/kilogram) and visual analog scale for pain at rest and movement for 24hours after surgery. The secondary outcome variables were time (minutes) to first rescue analgesic requirement and patient satisfaction scores. The patients, surgeons, and anesthesiologists collecting the data were blinded to the group allocation. Continuous and qualitative data were summarized using mean (standard deviation) and frequency distribution, respectively. About 45 patients were randomized into 3 equal groups. Mean age of the sample was 17.6±8.04years (males=24 [53%]; females=21 [47%]). Surgery for TMJA included gap arthroplasty (n=17), interpositional arthroplasty (n=24), and total TMJ replacement (n=4). Total fentanyl (micrograms) consumption during 24 hours was comparable between all the 3 groups and statistically not significant (P=.40). The pain scores (visual analog scale at rest and movement) were comparable at all time points. No significant difference was noted for time to first rescue analgesic requirement (P=.31). Patient satisfaction was higher in RC group as compared with R group (P=.009). No adverse effects were noted in any group. Within the confines of the sample size and the absence of power calculation, the study implies that wound infiltration with ropivacaine was as efficacious as when mixed with adjuvants, either clonidine or dexamethasone, for control of postoperative pain for 24hours.