Erector Spinae Plane Block Versus Transversus Abdominis Plane Block in Abdominoplasty Surgery

Overview

Abdominoplasty is one of the most popular body-contouring procedures. Patients that undergo body-contouring abdominoplasty usually have important analgesic requirements. Given the substantial incision and soft-tissue undermining associated with this procedure, postoperative pain is a concern for patients and surgeons. Previous studies have typically incorporated multiple nerve blocks to improve analgesia after abdominoplasty. Different anesthetic techniques have been developed to overcome this problem such as Epidural anesthesia, Transversus abdominis plane block either open technique or ultrasound-guided, Paravertebral block and Erector Spinea plane block. Improving postoperative pain control in this kind of surgery leads to earlier mobilization, shortened hospital stay, reduced hospital costs, and increased patient satisfaction. The ultrasound-guided erector spinae plane (ESP) block is a recent block described for various surgeries for postoperative analgesia. It is reported that it have an analgesic effect on somatic and visceral pain by affecting the ventral rami and rami communicantes that include sympathetic nerve fibres, as LA spreads through the paravertebral space. When performed bilaterally it has been reported to be as effective as thoracic epidural analgesia. The transversus abdominis plane (TAP) block is a technique of locoregional anesthesia that blocks the sensorial afferent nerves localized between the transversus abdominis muscle and the internal oblique muscle. In this study, the analgesic efficacy and duration of ultrasound (US) guided Erector spinea plane block and Transversus abdominis plane block when Lidocaine HCL is added as an adjuvant to bupivacaine will be compared.

Sample size was calculated using Power Analysis and Sample Size software program (PASS) version 15.0.5 for windows (2017) using previous results with the mean opioid consumption in the first postoperative day as the primary outcome. Effect size of 0.5 (medium effect size) was calculated using the difference between the mean opioid consumption in TAB group (140 mg) and that in ESPB group (124.6 mg) with an estimated standard deviation of 30 in both groups. This study will add a control group in which only intravenous analgesics will be used; hence the aforementioned effect size was used for sample size calculation using a one-way ANOVA test. Sample sizes of 18 patients in each group are needed to achieve 90% power (1-β) to detect differences among the means using an F test with a 0.05 significance level (α). The size of the variation in the means is represented by the effect size f = σm / σ, which is 0.5. A 20% drop out is expected so the drop-out inflated sample size will be 23 patients in each group.