Independent Predictors for Higher Postoperative Pain Intensity During Recovery After Open Thoracic Surgery: A Retrospective Analysis in 621 Patients

Objective. To evaluate two standard procedure-specific pain regimens and to assess independent predictors for higher pain intensity after thoracic surgery. Methods. Patients received either oral opioid analgesia (Opioid Group) or epidural analgesia and were then bridged to systemic opioid analgesia (EDA + O Group) in this retrospective observational study. Medical history, discharge letters, anesthetic protocols, and pain protocols were evaluated in 621 patients after open thoracotomy and assessed with a stepward back elimination in a multivariate logistic regression model. Results. Data of 621 thoracotomies in 2014 were analyzed, 309 patients in the Opioid Group and 312 patients in the EDA + O Group. Pain scores at rest and on coughing were significantly lower in the EDA1O Group on postoperative days (PODs) 1-4 (P<0.001). Stepwise backward elimination in multivariate logistic regression identified preexisting pain disease (P = 0.034), no epidural analgesia (P< 0.001), opioids in preoperative pain therapy (P< 0.001), and antidepressant medication (P50.003) as independent risk factors for higher pain intensity at rest on PODs 1-4. Same on PODs 5-8 with regard to opioids in preoperative pain therapy (P< 0.001) and antidepressant medication (P = 0.018). Moreover, on PODs 5-8, male gender had a lower risk (P<0.003) for pain, and preexisting musculosceletal disease had a lower risk for more postoperative pain (P = 0.009). On coughing, male gender and younger age proved to have a lower risk for postoperative pain on PODs 1-8 and on PODs 1-4, respectively. Opioids in preexisting pain therapy and antidepressant medication were identified as risk factors for pain on PODs 1-8 on coughing, and pain disease was identified as a risk factor for more pain on PODs 1-4 (P = 0.041). Moreover, preexisting cardiac disease indicated more pain on PODs 1-4 (P = 0.05), and musculoskeletal disease and neurological disease indicated more pain on PODs 5-8 (P= 0.041, and P = 0.023). Conclusions. We present data on independent risk factors for higher pain intensity during recovery after thoracotomy. The lack of postoperative epidural analgesia, female gender, preexisting opioid pain therapy, and chronic pain are the strongest risk factors for higher pain intensity. Antidepressant medication was identified as an independent risk factor at rest and on coughing on all PODs. Study limitations. The study design is retrospective.