Predicting Pain Intensity after Mandibular Third Molar Surgery using Cold Pressor Testing: A Quasi-Experimental Study

Background: Patients complain differently about their experiences of post-operative pain. However, clinicians are often guided by their own viewpoints despite the highly subjective nature of pain resulting in suboptimal post-operative pain management. This impacts negatively on the quality of life of patients in the immediate post-operative period. Investigating patients' pain behavior in the pre-operative period may therefore help to predict the intensity of post-operative pain, thereby assisting in identifying patients who are at risk of greater pain after third molar surgery, and allocating extra resources for pain control.

Aim: This study aims to predict the intensity of pain after third molar surgery by correlating post-operative pain perception with the sensory-discriminative dimension and affective response to a cold pressor stimulus.

Materials and methods: This study is a quasi-experimental study that was conducted in the oral surgery clinic of (name of hospital in the title page). The procedure was undertaken in an isolated clinic cubicle with well-controlled room temperature and minimal distraction. Study participants were recruited by convenience sampling. Forty-three consenting participants, 20 years and above, who met eligibility criteria were subjected to pre-operative cold pressor testing. Subsequently, third molar surgery was done and post-operative pain intensity was recorded at specific intervals. Data analyses were completed using IBM SPSS version 25. The Kolmogorov-Smirnov (KS) test was used to test for normality of continuous variables. Ordinal regression was used to test for contributory value of pre-operative measurement while Spearman's rank correlation test was used to test their degree of relationships with post-operative pain P < 0.05.

Result: The median pain threshold was 20 s (Interquartile Range, IQR 12.75-32.25) and the median pain tolerance was 33 s (IQR = 23.00-54.00) from the cold pressor test. The peak median pain score in this study was reached at 3-h after the last stitch. There was a statistically significant predictive effect of both variables on post-operative pain at 3-h.

Conclusion: Sensory-discriminative dimension and affective response to cold pressor test are significant predictors of peak post-operative pain after impacted mandibular third molar surgery.