Ultrasound-guided superficial cervical plexus block for analgesia in patients undergoing craniotomy via suboccipital retrosigmoid approach: study protocol of a randomised controlled trial

The Efficacy of Scalp Nerve Block in Postoperative Pain Management after Microvascular Decompression: A Randomized Clinical Trial

The scalp nerve block, created by injecting local anesthetics around the scalp nerves, is reported to effectively reduce pain after surgery. In this study, we evaluated the efficacy of scalp nerve block in patients with hemifacial spasm (HFS) undergoing microvascular decompression (MVD). Seventy-four patients who underwent MVD for HFS were enrolled. The block group received scalp nerve block with 0.5% ropivacaine before surgery. The primary outcome was cumulative dose of rescue analgesics 24 h postoperatively. The secondary outcomes were included pain scores, postoperative antiemetic consumption, and Quality of Recovery-15 scale. The cumulative dose of rescue analgesics at 24 h postoperatively was not significantly different between the two groups (4.80 ± 3.64 mg vs. 5.92 ± 3.95 mg, p = 0.633). However, the pain score was significantly reduced in the block group at 6, 12, and 24 h postoperatively. Postoperative antiemetic consumption was lower in the block group than the control group at 12 h. There were no significant differences between the two groups for other secondary outcomes. In MVD for HFS, a preoperative scalp nerve block might reduce postoperative pain in the early postoperative period, but a larger study using a multimodal approach is needed to confirm the efficacy of a scalp block.

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 (AUC1-48), 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 µg vs 9.8 µg, 95% CI: -8.0 to -2.4; p=0.001). The total perioperative consumption of sufentanil (45.0 µg vs 54.5 µg, 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 AUC1-48 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.

TRIAL REGISTRATION NUMBER

NCT04036812.

A preliminary animal study on the prediction of nerve block success using ultrasonographic parameters

This study aimed to evaluate the diagnostic value of ultrasonographic parameters as an indicator for predicting regional nerve block success. Ultrasound-guided sciatic nerve block was performed in seven dogs using either 2% mepivacaine (nerve-block group) or saline (sham-block group). The cross-sectional area (CSA), nerve blood flow (NBF), and shear wave velocity (SWV) of the sciatic nerve (SWV_N), SWV of the biceps femoris muscle (SWV_M), and their ratio (SWV_NMR) were measured at 0, 30, 60, and 90 min after the nerve block as well as the change rate of each parameter from the baseline. A receiver operating characteristic (ROC) curve analysis was performed to determine the diagnostic value of each parameter in the prediction of nerve block success. No significant changes were observed in the CSA or NBF in association with the nerve block. The SWV_N and SWV_NMR in the nerve-block group were significantly higher than those in the sham-block group at 90 min and at 30, 60, and 90 min, respectively (p < 0.05). The change rates of SWV_N and SWV_NMR in the nerve-block group were significantly higher than those in the sham-block group at all time points (p < 0.05). The ROC curve analysis showed that SWV_N had a moderate diagnostic accuracy (area under the curve [AUC], 0.779), whereas SWV_NMR and change rates of SWV_N and SWV_NMR had a high diagnostic accuracy (AUC, 0.947, 0.998, and 1.000, respectively). Ultrasonographic evaluation of the SWV_N and SWV_NMR could be used as indicators for predicting nerve block success.

Role of Superficial Cervical Plexus Nerve Block as an Adjuvant to Local Anesthesia in the Maxillofacial Surgical Practice

PURPOSE

Infiltration techniques are used as an adjuvant to regional anesthesia. In this study, we evaluated the efficacy of the superficial cervical plexus nerve block, as an alternative to local infiltration techniques; in the management of mandibular fractures and peri-mandibular space infections.

METHODS

A prospective randomized controlled trial was conducted on 24 patients having either mandibular fractures or peri-mandibular space infections; and were scheduled for surgery under regional anesthesia (eg, inferior alveolar nerve block, long buccal nerve block). The control group involved delivering a combination of regional anesthesia along with local infiltration. The experimental group received regional anesthesia with a superficial cervical plexus nerve block. The following parameters were studied: pain, onset and duration of anesthesia, time interval until first analgesic request, pulse rate and blood pressure [at different time intervals].

RESULTS

Intergroup comparison was done using unpaired t-test. Intragroup comparison was done using repeated measures ANOVA (for >2 observations), followed by a post hoc test. The superficial cervical plexus nerve block group showed highly statistically significant (P < .01) improvement in terms of intra-operative pain at 30 minutes, duration of anesthesia, intraoperative anesthetic requirement, time interval until first analgesic request and intraoperative diastolic blood pressure at 10 minutes.

CONCLUSION

It can be concluded that the combination of a regional anesthesia technique with a superficial cervical plexus nerve block is an alternative and safe technique for patients undergoing surgery for mandible fractures and perimandibular space infections, with clear advantages over local infiltration.