Neuropathic component of postoperative pain for predicting post-cesarean chronic pain at three months: a prospective observational study

BACKGROUND: Recent investigations have showed that cesarean section (CS) might be a cause of chronic pain, with a consequent decrease in quality of life. METHODS: Prospective observational study in a Spanish tertiary hospital. Main outcome measure was to assess early neuropathic characteristics of pain (DN2 score 23) one week after CS as a potential risk factor for post-cesarean section chronic pain (PCSCP) at three months. Secondary outcome was to identify other risk factors. Six hundred ten consecutive consenting patients undergoing CS were interviewed preoperatively, at discharge from recovery room and 24 hours postoperatively. Telephone follow-up interviews were conducted one week, three months and twelve months following surgery. RESULTS: We analyzed 597 consecutive patients. The incidence of PCSCP at three and twelve postoperative months were 6.2% and 1% respectively. Subjects with NRS score superior to five on movement one week after CS presented higher incidence of PCSCP (NRS superior to five: 19 [52.2%]; NRS equal or lower to five: 172 [30.9%]; P=0.009). On multivariate analysis neuropathic pain one week after CS was associated with a higher risk of PCSCP (AOR=1.63 [95% CI: 1.26-2.11; P<0.001]). Other identified risk factors for PCSCP were: uterine exteriorization during CS (AOR=3.89 [95% CI: 1.25-12.10; P=0.019]) and a lower gestational age (AOR=0.87 [95% CI: 0.78-0.96; P=0.008]). CONCLUSIONS: Incidence of PCSCP at three and twelve postoperative months was low, 6.2% and 1% respectively. Early neuropathic characteristics of pain after one week measured by neuropathic pain questionnaire, consisting of two questions (DN2)23/7 could be used to identify patients at risk for chronic post-surgical pain and develop preventive strategies.