Transversus abdominis plane block or subcutaneous wound infiltration after open radical prostatectomy: a randomized study

Abstract

Open radical retropubic prostatectomy (ORRP) is associated with moderate pain. We hypothesized that a transversus abdominis plane (TAP) block would reduce post-operative pain, morphine consumption and opioid-related side effects compared with wound infiltration and placebo in this population. This was a randomized, double-blind and placebo-controlled study. The operations were performed with patients in general anaesthesia. Patients were allocated to receive either bilateral TAP block (n = 23), wound infiltration (n = 25) or placebo (n = 25). Treatment was 40 ml ropivacaine 0.75% and placebo was 40 ml saline 0.9%. Pre-operatively, all patients received oral gabapentin, ibuprofen and paracetamol, followed by oral paracetamol and ibuprofen at regular doses and intervals, and patient-controlled analgesia with IV morphine from 0 h to 24 h post-operatively. Visual analogue scale pain score during mobilization 4 h post-operatively (primary outcome) did not differ significantly between the TAP block and placebo group (TAP 28 ± 22 mm vs. placebo 33 ± 18 mm, P = 0.64). Pain scores (as area under the curve) during the first 24 h were not significantly different among any of the three groups, neither at rest nor during mobilization. Morphine consumption (0-24 h) did not differ significantly between groups {TAP block = 15 [8-23] mg, infiltration 15 [8-36] mg, placebo 15 [3-30] mg, [median (interquartile range)]}. Levels of nausea, sedation and number of vomits were not different among the groups. Neither TAP block nor wound infiltration with ropivacaine improved a basic multimodal analgesic regimen with paracetamol, ibuprofen and gabapentin after ORRP.