Post-operative pain after ultrasound transversus abdominis plane block versus trocar site infiltration in laparoscopic nephrectomy: a prospective study

Background: Transversus abdominis plane (TAP) block is useful in reducing post-operative pain in laparoscopic nephrectomy compared to placebo. The purpose of this work is to compare post-operative pain and recovery after TAP block or trocar site infiltration (TSI) in this surgery. Methods: A prospective, single blinded study on patients scheduled for laparoscopic nephrectomy. Patients were assigned to two groups: TSI Group: trocar site infiltration at the end of surgery; TAP Group: unilateral ultrasound-guided TAP block after induction. Sevoflurane and remifentanit, in a target controlled infusion mode, were used for maintenance of general anesthesia. Before the end of surgery paracetamol, tramadol and morphine were administered. Visual analogue scale (VAS 0-100 ram) at rest and with cough was applied in three moments: in recovery room (T1 at admission and T2 before discharge) and 24h after surgery (T3). Pain scores with incentive spirometer were also evaluated at T3. In recovery, morphine was administered as a rescue drug whenever VAS > 30 mm. Time to oral intake, chair sitting, ambulation and length of hospital stay were evaluated 24 h after surgery. Statistical analysis: Student's t-test and Chi-square test, and linear regression models. A p-value <0.05 was considered significant. Data are presented as mean (SD). Results: Forty patients were enrolled in the study. The primary outcome variable. VAS pain scores did not show a statistical significant difference between groups (p>0.05). VAS at rest (TAP vs. TSI groups) was: T1 =33 +/- 29 vs. 39 +/- 32, T2= 10 +/- 9 vs. 17 +/- 18 and T3 =7 +/- 12 vs. 10 +/- 18. VAS with cough (TAP vs. TS' groups) was: Ti = 51 +/- 34 vs. 45 +/- 32, T2 =24 +/- 24 vs. 1+2 and T3 =20 +/- 23 vs. 23 +/- 23. VAS with incentive spirometer (TAP vs. TSI groups) was: T3 =21 +/- 27 vs. 21 +/- 25. Intraoperative remifentanil consumption was similar between TAP (0.16 +/- 0.07 mcg.kg(-1).min(-1)) and TSI (0.18 +0.9 mg.kg(-1).min(-1)) groups. There were no differences in opioid consumption between TAP (4.4 +/- 3.49 mg) and TSI (6.87 +/- 4.83 mg) groups during recovery. Functional recovery parameters were not statistically different between groups. Conclusions: Multimodal analgesia with TAP block did not show a significant clinical benefit compared with trocar site infiltration in laparoscopic nephrectomies. (C) 2016 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda.