Preemptiue Analgesia Clinical lixidence of Neu.roplasticitl, Contributing to Postoperatite Pain

Recent evidence suggests that surgical incision and othcr noxious perioperative cvents may induce prolongcd changes in central ncurnl function tbat later contribute to postopcrativc pain. Thc present study tcstcd the hypothesis that pstients receiving epidural fentanyl bE&rc incision would have less pain and need fetver analgcsics post operatively than patients receiving thc same dose ofepidural fentanyl afcr incision, Thirty patients (ASA physical status 2) scheduled for clcctive thoracic surg€ry through a posterolateral thoracotomy in cision were randomized to one of two groups of equal size and prospectivcly srudied in a double-blind manner. Dpidural catheters were pllccd ric the L2*L3 or L3-L4 interspaces preoperatively, and thc position wss confirmed with lidocaine. Group I received epidural fentanyl (4 pg/kg, in 20 ml nornral saline) bcfore surgical incision, followed by cpidural normal saline (20 ml) infused 15 min after incision. Group 2 reccivcd cpidural normal snline (20 ml) bcfore surgical incision, follorved by cpidural fentanyl (4 pg/kg, in 20 ml normal salinc) infused 15 min after incision. No additicnal analgosics wcre used bcforc or during the opcration. Arresthcsia was induccd with tltiopcntal (3-5 mg/kg) and maintained rlith NIO/O2 and isollurane. Paralysis rvas achieved'rvith pancuronium (0,1 mg/ kg), Postopemtive analgesia consislcd of patient-controllcd inha-