Cervical plexus blocks (CPBs) have been used in various head and neck surgeries to provide adequate anesthesia and/or analgesia; however, the block is performed in a narrow space in the region of the neck that contains many sensitive structures, multiple fascial layers, and complicated innervation. Since the intermediate CPB was introduced in addition to superficial and deep CPBs in 2004, there has been some confusion regarding the nomenclature and definition of CPBs, particularly the intermediate CPB. Additionally, as the role of ultrasound in the head and neck region has expanded, CPBs can be performed more safely and accurately under ultrasound guidance. In this review, the authors will describe the methods, including ultrasound-guided techniques, and clinical applications of conventional deep and superficial CPBs; in addition, the authors will discuss the controversial issues regarding intermediate CPBs, including nomenclature and associated potential adverse effects that may often be neglected, focusing on the anatomy of the cervical fascial layers and cervical plexus. Finally, the authors will attempt to refine the classification of CPB methods based on the target compartments, which can be easily identified under ultrasound guidance, with consideration of the effects of each method of CPB.

The fascia iliaca compartment block (FICB) provides an analgesic effect in patients with femur fractures. However, the postoperative pain after hip surgery is different from that after femur fracture, because of the difference in the degree and location of tissue trauma. Whether FICB provides effective postoperative analgesia in patients undergoing total hip arthroplasty is not well understood. Moreover, there is no prospective randomized study to evaluate FICB as a postoperative analgesia in hemiarthroplasty. Therefore, we performed a randomized and prospective study to determine the effect of FICB after hemiarthroplasty. The objective of this study was to compare the opioid consumption between patients who received intravenous patient-controlled analgesia (PCA) with and without FICB. Twenty-two patients aged 70 to 90 years who underwent bipolar hemiarthroplasty for femoral neck fracture were recruited and allocated randomly into 2 groups: FICB group (n = 11) and Non-FICB group (n = 11). All patients received spinal anesthesia with 10 mg of 0.5% hyperbaric bupivacaine. After surgery, the FICB was conducted using a modified technique with 0.2% ropivacaine (40 mL) under ultrasonographic guidance, and the intravenous PCA was administered to patients in both groups in the separate block room. The PCA was set up in the only bolus mode with no continuous infusion. The visual analog scale (VAS) and the opioid consumption were noted at 4, 8, 12, 24, and 48 hours postoperatively. The VAS was similar in both groups. The fentanyl requirement at 4, 8, and 12 hours was low in the FICB group. The total amount of fentanyl required in the first 24 hours was 246.3 μg in the FICB group and 351.4 μg in the Non-FICB group. No patient developed any residual sensory-motor deficit during the postoperative period. Patients in the Non-FICB group had nausea (n = 2), and pruritus (n = 1), and 1 patient had nausea in the FICB group during postoperative 2 days. The FICB has a significant opioid-sparing effect in first 24 hours after hemiarthroplasty. This suggests that FICB is an effective way for multimodal analgesia in hip surgery.

Chinese Medical Journal, China

Boohwi Hong, Seunguk Bang, Woosuk Chung, Subin Yoo, Jihyun Chung, and Seoyeong Kim. Korean J Pain 2019;32:206-14. https://doi.org/10.3344/kjp.2019.32.3.206

Because of its rapid onset time, recent years have seen an increase in the use of ultrasound (US)-guided popliteal sciatic nerve block (PSNB) via subparaneural injection for induction of surgical anesthesia. Moreover, in below-knee surgery, combined blocks, as opposed to sciatic nerve block alone, have become more common. These combined blocks often require a large volume of local anesthetic (LA), thus increasing the risk of local-anesthetic systemic toxicity (LAST). Thus, to decrease the risk of LAST, it is important to know the minimum effective volume (MEV) required for an adequate block. We, therefore, aimed to determine the MEV of ropivacaine 0.75% for induction of surgical anesthesia by the method of US-guided popliteal sciatic nerve block via subparaneural injection. Thirty patients underwent a US-guided PSNB with ropivacaine 0.75% at a 20-mL starting volume. Using a step-up/step-down method, we determined injection volumes for consecutive patients from the preceding patient's outcome. When an effective block was achieved within 40 minutes after injection, the next patient's volume was decreased by 2 mL. If the block failed, the next patient's volume was increased by 2 mL. The sensory and motor blockade was graded according to a 4-point scale. The block was considered a success if a combination of anesthesia and paresis (a score of 3 for both the sensory and motor nerves) was achieved within 40 minutes. The primary outcome measure was the MEV resulting in a successful subparaneural block of the sciatic nerve in 50% of patients (MEV50). Additionally, the data were processed with a probit regression analysis to determine the volume required to produce a complete sciatic nerve block in 90% of subjects (ED90). The MEV50 of 0.75% ropivacaine is 6.14 mL (95% confidence interval, 4.33–7.94 mL). The ED90 by probit analysis for a subparaneural injection was 8.9 mL (95% CI, 7.09–21.75 mL). The 6.14-mL MEV50 of ropivacaine 0.75% represents a 71% reduction in volume compared with neurostimulation techniques and a 14.7% reduction in volume compared with US-guided PSNB using the alternative perineural injection technique.

Kwon WJ, et al. J Korean Med Sci. 2018 Oct;33(45):e291. https://doi.org/10.3346/jkms.2018.33.e291