Ultrasound-guided superficial cervical plexus block reduces opioid consumption in patients undergoing craniotomy via suboccipital retrosigmoid approach: a randomized controlled trial

Introduction The effectiveness of superficial cervical plexus block (SCPB) at decreasing opioid use and improving hemodynamic stability during suboccipital retrosigmoid craniotomy has not been established. The aim of this study is to evaluate the analgesic effect of preoperative ultrasound-guided SCPB for craniotomy via a suboccipital retrosigmoid approach. Methods This was a prospective, single-center, randomized, double-blind, parallel-group controlled trial One hundred and six adult patients undergoing suboccipital retrosigmoid craniotomy were randomly allocated into either the SCPB group (n=53) to receive 10 mL of 0.5% ropivacaine or the control group (n=53) to receive 0.9% normal saline injected into the superficial layer of prevertebral fascia guided by ultrasound. The primary outcome was the cumulative consumption of sufentanil with patient-controlled intravenous analgesia (PCIA) within 24 hours. Secondary outcomes included the overall perioperative consumption of opioids, the area under the curve of the pain score from 1 hour to 48 hours (AUC(1-48)), intraoperative hemodynamic parameters, and anesthesia depth. Results The mean PCIA pump cumulative consumption of sufentanil in the first 24 hour postoperative period was significantly lowered by SCPB (5.0 mu g vs 9.8 mu g, 95% CI: -8.0 to -2.4; p=0.001). The total perioperative consumption of sufentanil (45.0 mu g vs 54.5 mu g, 95% CI: -14.8 to -4.1; p=0.001) was also significantly decreased by SCPB. The incidence of severe pain within 24 hours was decreased by SCPB (7.5% vs 26.4%, p=0.01). SCPB significantly decreased the AUC(1-48) of the pain score. Intraoperative hemodynamic parameters and anesthesia depth were similar between groups (p>0.05). Discussion SCPB provides effective analgesia in patients undergoing craniotomy and tumor resection via suboccipital retrosigmoid approach. SCPB demonstrates an opioid-sparing effect and allows for the maintenance hemodynamic stability at an appropriate depth of anesthesia.