Efficacy of preincisional versus post incisional unilateral ultrasound-guided transversus abdominis plane block in patients undergoing appendectomy under subarachnoid block

Background: Transversus abdominis plane (TAP) block produces effective postoperative analgesia and reduces postoperative opioid consumption after abdominal surgeries. It could be instituted preoperatively or postoperatively. Objectives: This study determined which period of institution of TAP block is more efficacious in postoperative analgesia in patients undergoing open appendicectomy. Patients and Methods: Eighty patients undergoing open appendicectomy were randomized, of which eight were excluded for various reasons (these were; three for protocol violations, four declined further participations, while one for prolonged surgery). A total of 72 patients received SAB, of which half received (n = 36) TAP block with 20 ml of 0.375% plain marcaine before skin incision (preoperative TAP block group) while the other half (n = 36) received same volume and concentration of TAP block at the end of surgery (postoperative TAP block group). Pain was evaluated postoperatively at rest and on movement by numerical rating scale (NRS) over 24 h. Results: Pain scores were significantly lower in the preoperative TAP block group than in the postoperative TAP block group, especially in the first 6 h (P < 0.001) postoperatively; although, both demonstrated lower pain score. Furthermore, total analgesic consumption (paracetamol and tramadol) was significantly higher in the postoperative TAP block group (P = 0.001 and P = 0.002). Conclusion: Preoperatively, administered TAP block increases time to first analgesic request, provides a longer duration of analgesia and reduces total analgesic requirement in comparison to postoperative TAP block in patients undergoing open appendicectomy.