A сomparison of the different regional anesthesia methods efficacy in chronic pain syndrom prevention in lung cancer surgery

INTERVENTION: All consecutive patients scheduled for thoracotomy are randomly assigned to into three groups: 1) thoracic epidural anesthesia (TEA) ; 2) paravertebral nerve block (PVB) 3) intercostal nerve block (INB) using Research Randomizer (http://www.graphpad.com). In the TEA group, an epidural catheter is placed at T4‐T6 interspace before induction. Then the intra‐epidural infusion of ropivacaine 0.3%, fentanyl 4 µg/mL and epinephrine 2 µg/mL is started at 5‐15 mL/h. Postoperatively, this group received an anesthetic solution containing ropivacaine 0.3%, fentanyl 4 µg/mL and epinephrine 2 µg/mL for 2 days. After day 2, ropivacaine 0.2% was infused alone until the 5th postoperative day. In the PNB group, paravertebral catheter was placed using ultrasound at the T5‐T6 level. Before the induction of general anesthesia, the patients received a bolus of lidocaine 2% ‐ 10 mL and the same anesthetic solution as the TEA group in the volume of 20 ml. At the end of surgery, a second bolus dose (20 ml) of the anesthetic solution was administered. Postoperatively the patients received the anesthetic solution (as in TEA group) with an infusion rate at 8‐12 mL/h during the first 2 days, and then this solution was changed to ropivacaine 0.2% and the infusion was prolonged until the 5th postoperative day. In the INB group, an intercostal nerve block was provided by the surgical team after the lung or lobe resection. A solution of ethanol 96% ‐ 30 mL and novocain 0.5% ‐ 30 mL was mixed and injected into the intercostal space subpleuraly paravertebraly just below the intercostal nerve at three levels (20 mL of solution at each level) to provide the intercostal block at the level of thoracotomy, above and below the incision as it was described in the literature [40,41]. Postoperatively, additional injections of a local anesthetic were administered transdermally in the patients with acute pain syndrome defined by a visual analog score (VAS) above 50 mm. The patients received 0.5% solutio CONDITION: Chronic post‐thoracotomy pain syndrome (CPTPS) is one of the most often side effects in lung surgery. After thoracotomy, its incidence ranges from 30% to 40%. The CPTPS is defined as pain that develops after surgical intervention and lasts for at least 2 months (International Association for the Study of Pain). The mechanism of the CPTPS is a long‐lasting non‐curable acute surgical pain associated with surgical trauma and inflammation of chest wall, lung and pleural parenchyma. For this reason, the APTPS should be effectively prevented and treated as soon as possible. In addition, the presence of a neuropathic component due to injury or irritation of the intercostal nerves is reported, as a mechanism of the pain chronicization. The emergence of a neuropathic pain component is critical for thoracotomy and thoracoscopy due to the features of the chest wall innervation and the surgical techniques. ; Respiratory ; Chronic post‐thoracotomy pain syndrome (CPTPS) PRIMARY OUTCOME: 1. Frequency and intensity of the CPTPS is measured using the Visual Analogue Scale (0 = no pain and 100 mm = worst possible pain) at 6 months after surgery; 2. Effectiveness of TEA, PVB, and INB in CPTPS prevention are measured using the Visual Analogue Scale (0 = no pain and 100 mm = worst possible pain) at 6 months after surgery SECONDARY OUTCOME: 1. Intensity of APTPS and CPTPS between groups are measured using the Visual Analogue Scale (0 = no pain and 100 mm = worst possible pain) at 7 days, 1 and 6 months after surgery.; 2. Pain is measured using the Visual Analogue Scale (0 = no pain and 100 mm = worst possible pain) at 7 days, 1 and 6 months after surgery; INCLUSION CRITERIA: All consecutive patients scheduled for thoracotomy were screened for study inclusion using the following eligibility criteria: adult patients and ASA physical status from I to III.