Postcesarean section pain prediction by preoperative experimental pain assessment

Background: Postcesarean section pain is a common cause of acute pain in obstetrics, yet pain relief and patient satisfaction are still inadequate in many cases. The present study was conducted to determine whether preoperative assessment of experimental pain perception by quantitative sensory tests could predict the level of postcesarean section pain. Methods: Fifty-eight women who were scheduled for elective cesarean section were enrolled in the study. Heat pain threshold and magnitude estimation of suprathreshold pain stimuli at 44°-48°C were assessed for both algosity (the sensory dimension of pain intensity) and unpleasantness 1 or 2 days before surgery. The day after the operation, the women reported the level of pain at the surgical wound on a visual analog scale at rest and during activity. Regression analysis was performed to evaluate the usefulness of preoperative scores in predicting postcesarean section pain. Results: Postoperative visual analog scale scores at rest and during activity significantly correlated with preoperative suprathreshold pain scores at 44°-48°C (r = 0.31-0.58 for algosity and r = 0.33-0.74 for unpleasantness). The stimulus of 48°C was found to be the best predictor of postoperative pain for both conditions (r = 0.434-0.527; P < 0.01). In contrast to suprathreshold pain stimuli, pain threshold was not correlated with postoperative pain. Conclusions: The results show that a simple and quick preoperative test is useful in identifying those women who will experience greater pain after a cesarean section. This test may be suggested for caregivers to tailor the postoperative treatment to specific patient needs and to improve postoperative outcome and patient satisfaction.