Transversus Abdominis Plane Block Reduced Early Postoperative Pain after Robot-assisted Prostatectomy: a Randomized Controlled Trial

Analgesic effect of transversus abdominis plane block (TAP block) in lower major abdominal laparoscopic surgery with about 5 cm of maximum surgical scar has been controversial. We hypothesized that TAP block has benefits, so the analgesic effect of TAP block after robot-assisted laparoscopic prostatectomy (RALP) was evaluated. One hundred patients were enrolled in this prospective, double-blinded, randomized study. Standardized general anesthesia with wound infiltration on camera port and fentanyl dose limit of 3 mu g/kg was provided. Ultrasound-guided, single-shot subcostal TAP block with either 0.375% ropivacaine (Ropivacaine group, 48 patients) or normal saline (Control group, 52 patients) was performed by anesthesiologist in charge (34 anesthesiologists) after surgical procedure. Pain score using numerical rating scale (NRS) and postoperative intravenous fentanyl were evaluated for the first 24 postoperative hours. Median values (interquartile range) of NRS scores when the patients were transferred to post-anesthesia care unit (PACU) were 5 (2-7) in Ropivacaine group and 6 (4-8) in Control group at rest (P = 0.03), 5 (2-8) in Ropivacaine group and 7 (5-8) in Control group during movement (P < 0.01). These significant differences disappeared at the time of discharging PACU. Fentanyl doses for the first 24 postoperative hours were 210 mu g (120-360) in Ropivacaine group and 200 mu g (120-370) in Control group (P = 0.79). These results indicated that subcostal TAP block by anesthesiologists of varied level of training reduced postoperative pain immediate after RALP. TAP block had fundamental analgesic effect, but this benefit was too small to reduce postoperative 24-hour fentanyl consumption.