BACKGROUND The sensory innervation of the shoulder is complex and there are variations in the branching patterns of the sensory fibres. Articular branches from the axillary nerve to the subacromial bursa are described in more than 50% of investigated shoulders but the isolated contribution of sensory input from the axillary nerve has never been investigated clinically. We hypothesized that a selective block of the axillary nerve would reduce morphine consumption and pain after arthroscopic subacromial decompression. METHODS We included 60 patients in a randomized, blinded, placebo-controlled study. Patients were randomized to a preoperative selective ultrasound-guided axillary nerve block with 20 mL ropivacaine (7.5 mg/mL) or 20 mL saline. Primary outcome was intravenous morphine consumption 0-4 h postoperatively. Secondary outcome was postoperative pain evaluated by a visual analogue scale (VAS) score (0-100). RESULTS We analysed data from 50 patients and found no significant difference in 0-4 h postoperative morphine consumption between the two groups (ropivacaine 14 mg, placebo 18 mg (P = 0.12)). There was a reduction in postoperative pain: VAS 0-4 h (area under the curve) (ropivacaine 135, placebo 182 (P = 0.03)), VAS after 8 h (ropivacaine 9, placebo 20 (P = 0.01)) and VAS after 24 h (ropivacaine 7, placebo 18 (P = 0.04)). Eight out of 19 patients with a successful selective axillary nerve block needed an interscalene brachial plexus escape block. CONCLUSIONS Selective block of the axillary nerve has some pain relieving effect, but in this setting the effect was unpredictable, variable and far from sufficient in a large proportion of the patients. TRIAL REGISTRATION ClinicalTrials.gov (NCT01463865). Registered: November 1, 2011.

中文翻译：

---

评估关节镜下肩峰下减压后选择性腋窝神经阻滞影响的随机对照试验。

背景技术肩部的感觉神经支配是复杂的，并且感觉纤维的分支图案存在变化。在超过50％的被调查肩膀中描述了从腋神经到肩峰滑囊的关节分支，但从未在临床上研究过从腋神经感觉输入的孤立贡献。我们假设，在关节镜下肩峰下减压后，选择性阻断腋神经将减少吗啡的消耗和疼痛。方法我们在一项随机，双盲，安慰剂对照研究中纳入了60名患者。患者被随机分配至术前用20 mL罗哌卡因（7.5 mg / mL）或20 mL生理盐水进行的超声引导下选择性腋窝神经阻滞。主要结果是术后0-4小时静脉内服用吗啡。次要结果是通过视觉模拟量表（VAS）评分（0-100）评估术后疼痛。结果我们分析了50例患者的数据，发现两组术后0-4 h吗啡消耗量无显着差异（罗哌卡因14 mg，安慰剂18 mg（P = 0.12））。术后疼痛有所减轻：VAS 0-4小时（曲线下面积）（罗哌卡因135，安慰剂182（P = 0.03）），术后8小时的VAS（罗哌卡因9，安慰剂20（P = 0.01））和VAS 24小时后（罗哌卡因7，安慰剂18（P = 0.04））。在成功选择腋窝神经阻滞的19位患者中，有8位需要斜肌间臂丛神经逃逸阻滞。结论腋神经的选择性阻滞具有一定的止痛作用，但在这种情况下，这种作用是不可预测的，可变的，并且在大部分患者中还远远不够。试验注册ClinicalTrials.gov（NCT01463865）。注册日期：2011年11月1日。