Montreal General Hospital, Department of Anesthesia, McGill University, Montreal, Quebec, Canada.
Reg Anesth Pain Med. 2018 Aug;43(6):590-595. doi: 10.1097/AAP.0000000000000767.
This randomized trial compared ultrasound (US)-guided interscalene block (ISB) and small-volume supraclavicular block (SCB) for arthroscopic shoulder surgery. We hypothesized that SCB would provide equivalent analgesia to ISB 30 minutes after surgery without the risk of hemidiaphragmatic paralysis (HDP).
All patients received an US-guided intermediate cervical plexus block. In the ISB group, US-guided ISB was performed with 20 mL of levobupivacaine 0.5% and epinephrine 5 μg/mL. In the SCB group, US-guided SCB was carried out using 20 mL of the same local anesthetic agent: 3 and 17 mL were deposited at the "corner pocket" (ie, intersection of the first rib and subclavian artery) and posterolateral to the brachial plexus, respectively. A blinded investigator assessed ISBs and SCBs every 5 minutes until 30 minutes using a composite scale that encompassed the sensory function of the supraclavicular nerves, the sensorimotor function of the axillary nerve, and the motor function of the suprascapular nerve. We considered the blocks complete if, at 30 minutes, a composite score equal or superior to 6 points (out of 8 points) was achieved. Thus, onset time was defined as the time required to reach a minimal composite score of 6 points. The blinded investigator also assessed the presence of HDP at 30 minutes with US. Subsequently, all patients underwent general anesthesia. Postoperatively, a blinded investigator recorded pain scores at rest at 0.5, 1, 2, 3, 6, 12, and 24 hours. Patient satisfaction at 24 hours, consumption of intraoperative and postoperative narcotics, and opioid-related adverse effects were also tabulated.
Both groups displayed equivalent postoperative pain scores at 0.5, 1, 2, 3, 6, 12, and 24 hours. Interscalene blocks resulted in a higher incidence of HDP (95% vs 9%; P < 0.001), a shorter onset time, and a higher proportion of patients with minimal composite scores of 6 points at 30 minutes (100% vs 77%; P = 0.048). However, no intergroup differences were found in terms of performance time, procedural pain, number of needle passes, intraoperative/postoperative opioid consumption, adverse effects, and patient satisfaction at 24 hours.
Compared with ISB, small-volume SCB results in equivalent postoperative analgesia and a lower incidence of HDP. Because the latter cannot be completely avoided with small-volume SCB, further trials are required to investigate the optimal diaphragm-sparing nerve block for shoulder surgery.
This study was registered at ClinicalTrials.gov, identifier NCT03224884.
本随机试验比较了超声引导下肌间沟阻滞（ISB）和锁骨上小容量阻滞（SCB）在关节镜肩关节手术中的效果。我们假设，与 ISB 相比，SCB 在手术后 30 分钟内提供等效的镇痛效果，且不会引起膈肌麻痹（HDP）。
所有患者均接受超声引导下颈丛阻滞。在 ISB 组中，使用 20 mL 左旋布比卡因 0.5%和肾上腺素 5 μg/mL 进行超声引导下 ISB。在 SCB 组中，使用相同的局部麻醉剂进行超声引导下 SCB：3 毫升和 17 毫升分别注入到“角囊”（即第一肋和锁骨下动脉的交点）和臂丛后外侧。一名盲法研究者每隔 5 分钟评估 ISB 和 SCB，直到 30 分钟，采用包括锁骨上神经感觉功能、腋神经感觉运动功能和肩胛上神经运动功能的综合评分。如果在 30 分钟时达到 6 分（满分 8 分）或更高的综合评分，则认为阻滞完全。因此，起效时间定义为达到最小综合评分 6 分所需的时间。盲法研究者还在 30 分钟时使用超声评估 HDP 的发生情况。随后，所有患者均接受全身麻醉。术后，盲法研究者记录患者在 0.5、1、2、3、6、12 和 24 小时的静息疼痛评分。还记录了 24 小时时的患者满意度、术中及术后阿片类药物的使用情况以及与阿片类药物相关的不良反应。
两组患者在 0.5、1、2、3、6、12 和 24 小时的术后疼痛评分均无差异。ISB 组出现更高的 HDP 发生率（95%比 9%；P<0.001）、更短的起效时间以及更高比例的患者在 30 分钟时达到最小综合评分 6 分（100%比 77%；P=0.048）。然而，两组在操作时间、程序疼痛、进针次数、术中/术后阿片类药物使用、不良反应以及 24 小时时的患者满意度方面均无差异。
与 ISB 相比，小容量 SCB 可产生等效的术后镇痛效果，且 HDP 发生率更低。由于小容量 SCB 并不能完全避免 HDP，因此需要进一步研究用于肩部手术的最佳膈神经保留神经阻滞方法。
本研究在 ClinicalTrials.gov 注册，注册号为 NCT03224884。
