Evaluation of the effectiveness of NSAIDs in the prevention of postoperative pain. Comparison between pre- and postoperative administration of sodium naproxen in orthopedic surgery

The aim of the study was to assess the efficacy of the preoperative sodium Naproxen administration to reduce analgesic requirements in the postoperative period. 75 patients (ASA I-II), 50 male and 25 female, aged between 25 and 70 years and weighed between 50 and 90 kg, undergoing lumbar laminectomy were subjected to the same anesthetic technique. Patients were allocated randomly to one of three groups. Group I received intravenous sodium naproxen (550 mg) immediately after induction of anesthesia. Group II received intravenous sodium Naproxen (550 mg) at the end of surgery. Group III received intravenous normal saline immediately after induction of anesthesia. Postoperative every patient was given by request intramuscular Buprenorphine (0.3 mg) for pain relief (at 6 h intervals). Buprenorphine requirements in the group I were significantly lower than in either of the other groups (p < 0.01 and p < 0.0001 respectively), while significant differences were not observed between group II and III. Moreover the 54% of patients in the group I did not require analgesic drugs in the postoperative period in opposition to the 20% of pts. in the group II and the 12% of pts. in the group III (p < 0.05 and p < 0.01 respectively). We conclude that NSAIDs when given before tissue damage may prevent nociceptor sensitisation and probably reduce hyperexcitability of the spinal cord. Preoperative administration of NSAIDs provides better protection against peripheral nerve sensitisation than postoperative administration.