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

Abstract

BackgroundTransversus 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. MethodsA 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 remifentanil, 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 0–100mm) 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>30mm. Time to oral intake, chair sitting, ambulation and length of hospital stay were evaluated 24h 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). ResultsForty 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. TSI groups) was: T1=51±34 vs. 45±32, T2=24±24 vs. 33±23 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±0.07mcg.kg−1.min−1) and TSI (0.18±0.9mcg.kg−1.min−1) groups. There were no differences in opioid consumption between TAP (4.4±3.49mg) and TSI (6.87±4.83mg) groups during recovery. Functional recovery parameters were not statistically different between groups. ConclusionsMultimodal analgesia with TAP block did not show a significant clinical benefit compared with trocar site infiltration in laparoscopic nephrectomies.