ACUTE PAIN AFTER THORACIC-SURGERY PREDICTS LONG-TERM POSTTHORACOTOMY PAIN

Objective: Long-term pain is a common sequela of thoracotomy, occurrin g in approximately 50% of patients 2 years after thoracic surgery. Des pite this alarming statistic, little is known about the factors respon sible for the transition of acute to chronic pain. The aim of the pres ent study is to identify predictors of long-term post-thoracotomy pain . Design: Follow-up was for 1.5 years for patients who had participate d in a prospective, randomized, controlled trial of preemptive, multim odal analgesia. Setting: Subjects were recruited from a tertiary care center. Patients: Thirty patients who had undergone lateral thoracotom y were followed up by telephone, administered a structured interview, and classified according to long-term pain status. Main Outcome Measur es: Present pain status was measured by a verbal rating scale (VAS). M easures obtained within the first 48 h after surgery were compared bet ween patients with and without pain 1.5 years later. These include VAS pain scores at rest and after movement, McGill Pain Questionnaire dat a, patient-controlled morphine consumption (mg), and pain thresholds t o pressure applied to a rib contralateral to the thoracotomy incision. Results: Fifty-two percent of patients reported long-term pain. Early postoperative pain was the only factor that significantly predicted l ong-term pain. Pain intensity 24 h after surgery, at rest, and after m ovement was significantly greater among patients who developed long-te rm pain compared with pain-free patients. A significant predictive rel ationship was also found at 24 and 48 h using the McGill Pain Question naire. Cumulative morphine was comparable for the two groups. Pain thr esholds to pressure applied to a rib contralateral to the incision did not differ significantly between the groups. Conclusion: Aggressive m anagement of early postoperative pain may reduce the likelihood of lon g-term post-thoracotomy pain.