From the Anesthesia, Intensive Care and Pain Therapy, AUSL, IRCCS (Scientific Research and Care Institute), Reggio Emilia, Italy (G.C., F.B., G.F.D.) the Anesthesia, Intensive Care and Pain Therapy, Ospedale di Circolo, Varese, Italy (A.L.A.) the Anesthesia and Intensive Care, IRCCS Ospedale San Raffaele, Italy (M.G.) the Anesthesia and Pain Therapy, ASST Gaetano Pini-CTO, Milano, Italy (V.L.E.C.).
Anesthesiology. 2018 Aug;129(2):241-248. doi: 10.1097/ALN.0000000000002254.
WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Both extra- and intraneural sciatic injection resulted in significant axonal nerve damage. This study aimed to establish the minimum effective volume of intraneural ropivacaine 1% for complete sensory-motor sciatic nerve block in 90% of patients, and related electrophysiologic variations.
Forty-seven consecutive American Society of Anesthesiologists physical status I-II patients received an ultrasound-guided popliteal intraneural nerve block following the up-and-down biased coin design. The starting volume was 15 ml. Baseline, 5-week, and 6-month electrophysiologic tests were performed. Amplitude, latency, and velocity were evaluated. A follow-up telephone call at 6 months was also performed.
The minimum effective volume of ropivacaine 1% in 90% of patients for complete sensory-motor sciatic nerve block resulted in 6.6 ml (95% CI, 6.4 to 6.7) with an onset time of 19 ± 12 min. Success rate was 98%. Baseline amplitude of action potential (mV) at ankle, fibula, malleolus, and popliteus were 8.4 ± 2.3, 7.1 ± 2.0, 15.4 ± 6.5, and 11.7 ± 5.1 respectively. They were significantly reduced at the fifth week (4.3 ± 2.1, 3.5 ± 1.8, 6.9 ± 3.7, and 5.2 ± 3.0) and at the sixth month (5.9 ± 2.3, 5.1 ± 2.1, 10.3 ± 4.0, and 7.5 ± 2.7) (P < 0.001 in all cases). Latency and velocity did not change from the baseline. No patient reported neurologic symptoms at 6-month follow-up.
The intraneural ultrasound-guided popliteal local anesthetic injection significantly reduces the local anesthetic dose to achieve an effective sensory-motor block, decreasing the risk of systemic toxicity. Persistent electrophysiologic changes suggest possible axonal damage that will require further investigation.
坐骨神经外膜和内膜注射均可导致明显的轴突神经损伤。本研究旨在确定 90%患者完全感觉-运动性坐骨神经阻滞的最小有效神经内罗哌卡因 1%体积，并探讨相关的电生理变化。
47 例连续的美国麻醉医师协会（ASA）Ⅰ-Ⅱ级患者，根据上下偏倚硬币设计，接受超声引导的腘窝神经内阻滞。起始容积为 15ml。进行基线、5 周和 6 个月的电生理测试。评估振幅、潜伏期和速度。6 个月时还进行了电话随访。
罗哌卡因 1%在 90%患者中用于完全感觉-运动性坐骨神经阻滞的最小有效体积为 6.6ml（95%CI，6.4 至 6.7），起效时间为 19±12min。成功率为 98%。基线时踝、腓骨、外踝和比目鱼肌的动作电位（mV）振幅分别为 8.4±2.3、7.1±2.0、15.4±6.5 和 11.7±5.1。第 5 周时明显降低（4.3±2.1、3.5±1.8、6.9±3.7 和 5.2±3.0），第 6 个月时进一步降低（5.9±2.3、5.1±2.1、10.3±4.0 和 7.5±2.7）（所有病例均 P<0.001）。潜伏期和速度从基线开始没有变化。在 6 个月的随访中，没有患者报告有神经症状。
神经内超声引导的腘窝局部麻醉注射显著降低了实现有效感觉-运动阻滞的局部麻醉剂量，降低了全身毒性的风险。持续的电生理变化提示可能存在轴突损伤，需要进一步研究。
