Preoperative scar hyperalgesia is associated with post-operative pain in women undergoing a repeat Caesarean delivery.

C M Ortner, M Granot, P Richebé, M Cardoso, L Bollag, R Landau

Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA. cortner@uw.edu

European journal of pain (London, England) 2013 Jan

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Over 1.4 million Caesarean deliveries are performed annually in the United States, out of which 30% are elective repeat procedures. Post-operative hyperalgesia is associated with an increased risk for persistent post-surgical pain; however, there are no data on whether residual scar hyperalgesia (SHA) from a previous Caesarean delivery (CD) persists until the next delivery. We hypothesized that residual SHA may be present in a substantial proportion of women and is associated with increased post-operative pain. One hundred and sixty-three women scheduled for a repeat CD under spinal anaesthesia were enrolled into the study. Mechanical temporal summation (mTS) and SHA index were measured preoperatively. SHA was considered present when the index was >0. Post-operative pain scores at 12, 24 and 48 h and wound hyperalgesia (WHA) at 48 h were recorded. SHA was present in 67 women 41% with a median SHA index of 0.42 (Q (25) = 0.25; Q (75) = 1.1, range 0.03-4.25). Women with SHA had overall higher post-operative pain scores and SHA was correlated with preoperative mTS (r = 0.164, p < 0.05), post-operative pain severity (r = 0.25, p < 0.002) and WHA at 48 h (r = 0.608, p < 0.001). Severe pain (visual analogue pain scale-S48 ≥ 7, n = 20) was predicted with a sensitivity and specificity of 60% and 62%, respectively. Positive predictive value was 18% and negative predictive value was 92%. Preoperative SHA is present in 41% of women scheduled for repeat CD and is associated with increased mTS and post-operative pain. Screening for preoperative SHA may predict women at risk for increased post-operative pain, and guide post-operative analgesia to include anti-hyperalgesic drugs. © 2012 European Federation of International Association for the Study of Pain Chapters.

Citation

C M Ortner, M Granot, P Richebé, M Cardoso, L Bollag, R Landau. Preoperative scar hyperalgesia is associated with post-operative pain in women undergoing a repeat Caesarean delivery. European journal of pain (London, England). 2013 Jan;17(1):111-23