PREDICTION OF POSTOPERATIVE PAIN AFTER LOWER THIRD MOLAR SURGERY

Abstract

Introduction Severe acute pain after lower third molar surgery (L3MS) has been reported in 16-20 % of the patients. The objective of the present study was to evaluate the predictive potential of a combination of preoperative psychological and psycho-physiological variables in estimating severity of postoperative pain, following this high volume, out-patient surgical procedure. Methods Following ethical committee approval and informed consent, 40 consecutive patients scheduled for L3MS were studied. Preoperative psychometric indicators of anxiety, depression and vulnerability were evaluated by patient questionnaires. Quantitative sensory testing was performed with a Modular Sensory Analyzer (Somedic AB, Sweden) using a contact thermode applied to the skin. Thermal thresholds and supra-threshold heat pain perception (1 s: 44, 45, 46, 47 and 48°C [VAS]) were evaluated. Standardized surgery was performed (LE) during local anesthesia. Postoperative pain management was with rescue acetaminophen 1 g and ibuprofen 600 mg. The patients were instructed to daily record pain (VAS) at rest, and, during mouth-opening, eating and drinking and requirement of analgesics for 14 days following surgery. Results Thirty-eight patients completed the study. Median duration of surgery was 11 min (range 2-21 min). Eight patients returned to the clinic because of pain. Total rescue doses of acetaminophen and ibuprofen were 13.5 g (6.5-22.2 g [median (IQ range)]) and 7 g (3.9-13.8 g), respectively. Moderate to severe pain (VAS > 30) was reported by 23/38 at rest, 25/38 during mouth-opening, 24/38 during drinking and 29/38 during eating. In a multiple regression model the combination of psychological vulnerability and heat pain perception rendered a predictive model that could account for 20 to 40 % of the variance in postoperative pain during resting and dynamic conditions following L3MS (P = 0.001). Implementation of clinically relevant preoperative screening methods may offer more efficacious pain therapies to pain susceptible individuals undergoing lower third molar surgery