Gupta Gaurav, Radhakrishna Mohan, Tamblyn Isaac, Tran D Q, Besemann Markus, Thonnagith Atikun, Elgueta Maria Francisca, Robitaille Marie Eve, Finlayson Roderick J
Department of Anesthesia, Montreal General Hospital.
US Army Med Dep J. 2017 Jul-Sep(2-17):33-38.
This prospective, randomized trial compared neurostimulation (NS) and ultrasound (US) guided lateral femoral cutaneous nerve (LFCN) block. We hypothesized that US would result in a shorter total anesthesia-related time (sum of performance and onset times).
Twenty-one volunteers were enrolled. The right lower limb was randomized to an NS- or US-guided LFCN block. The alternate technique was employed for the left lower limb. With NS, paresthesias were sought in the lateral thigh at a stimulatory threshold of 0.6 mA (pulse width=0.3 ms; frequency=2 Hz) or lower. With US, local anesthetic was deposited under the inguinal ligament, ventral to the iliopsoas muscle. In both groups, 5 mL of lidocaine 2% were used to anesthetize the nerve. During the procedure of the block, the performance time and number of needle passes were recorded. Subsequently, a blinded observer assessed sensory block in the lateral thigh every minute until 20 minutes. Success was defined as loss of pinprick sensation at a point midway between the anterior superior iliac spine and the lateral knee line. The blinded observer also assessed the areas of sensory block in the anterior, medial, lateral, and posterior aspects of the thigh and mapped this distribution onto a corresponding grid.
Both modalities provided comparable success rates (76.2%-95.2%), performance times (162.1 to 231.3 seconds), onset times (300.0 to 307.5 seconds) and total anesthesia related-times (480.1 to 554.0 seconds). However US required fewer needle passes (3.2±2.9 vs 9.5±12.2; P=.009). There were no intergroup differences in terms of the distribution of the anesthetized cutaneous areas. However considerable variability was encountered between individuals and between the 2 sides of a same subject. The most common areas of sensory loss included the central lateral two-eighths anteriorly and the central antero-inferior three-eighths laterally.
Ultrasound guidance and NS provide similar success rates and total anesthesia-related times for LFCN block. The territory of the LFCN displays wide inter- and intra-individual variability.
这项前瞻性随机试验比较了神经刺激（NS）和超声（US）引导下的股外侧皮神经（LFCN）阻滞。我们假设超声引导会使总的麻醉相关时间（操作时间和起效时间之和）更短。
招募了21名志愿者。将右下肢随机分配接受NS或US引导的LFCN阻滞。左下肢采用另一种技术。采用NS时，在大腿外侧寻找感觉异常，刺激阈值为0.6 mA（脉宽 = 0.3 ms；频率 = 2 Hz）或更低。采用US时，将局部麻醉药注射到腹股沟韧带下方、髂腰肌前方。两组均使用5 mL 2%利多卡因麻醉神经。在阻滞过程中，记录操作时间和进针次数。随后，由一位不知情的观察者每分钟评估一次大腿外侧的感觉阻滞情况，直至20分钟。成功定义为在前上棘和外侧膝线中点处针刺感觉消失。这位不知情的观察者还评估了大腿前、内、外和后侧的感觉阻滞区域，并将这种分布绘制在相应的网格上。
两种方法的成功率（76.2% - 95.2%）、操作时间（162.1至231.3秒）、起效时间（300.0至307.5秒）和总的麻醉相关时间（480.1至554.0秒）相当。然而，超声引导所需的进针次数更少（3.
