Department of Anesthesiology and Perioperative Medicine, University Hospital, 530 S. Jackson St., Louisville, KY 40202, USA.
Anesth Analg. 2010 Mar 1;110(3):958-63. doi: 10.1213/ANE.0b013e3181c95b4e. Epub 2009 Dec 23.
Blockade of the sciatic nerve is necessary for complete analgesia of the lower extremity using peripheral nerve blocks. We identified the sciatic nerve in relation to the ischial tuberosity in fresh cadaver dissections as well as in patients to compare sciatic nerve blockade using the conventional approach versus our experimental approach. Specifically, we tested the hypothesis that in patients in the prone position, our novel approach (changing the point of needle insertion to 3 cm lateral from the ischial tuberosity) requires fewer needle passes and less time.
The location of the sciatic nerve in relation to the ischial tuberosity was identified in 20 cadavers; this information was used to devise an alternative approach to the sciatic nerve. In a randomized, controlled, crossover patient study, we compared a prone subgluteal approach (conventional approach, n = 19) with an experimental approach with the insertion point 3 cm lateral to the midpoint of ischial tuberosity with patients in prone position (n = 20). We recorded the number of passes and the time taken to obtain an initial sciatic nerve twitch at a current of 1.5 mA and a twitch at <0.5 mA.
The sciatic nerve averaged 2.8 +/- 0.4 cm from the midpoint of ischial tuberosity in cadavers in prone position. When needles were inserted from surface landmarks, those inserted through the experimental insertion point consistently transected the sciatic nerve. In contrast, needles inserted through the conventional approach were 2.27 +/- 0.47 cm lateral to the sciatic nerve. Clinically, our experimental approach required fewer passes to obtain a sciatic nerve twitch than the conventional approach. We were unable to obtain a twitch in 55% of patients with the conventional approach and converted them to the experimental approach. In patients originally assigned to the experimental approach and those switched to the experimental approach after failure with the conventional approach, we obtained the first sciatic nerve twitch in 1 pass in 45% of the patients and in 3 passes in 85%.
We describe a landmark that is more effective for identifying the location of the sciatic nerve than that used for the prone subgluteal approach.
在外周神经阻滞中，为了实现下肢的完全镇痛，需要阻滞坐骨神经。我们在新鲜尸体解剖和患者中确定坐骨神经与坐骨结节的关系，以比较传统方法和我们的实验方法的坐骨神经阻滞。具体来说，我们检验了这样一个假设，即对于俯卧位的患者，我们的新方法（将进针点从坐骨结节向外侧移动 3 厘米）需要更少的进针次数和更少的时间。
我们在 20 具尸体中确定了坐骨神经与坐骨结节的位置关系，并利用这些信息设计了一种新的坐骨神经进针方法。在一项随机、对照、交叉患者研究中，我们比较了俯卧位下单侧臀部入路（传统方法，n=19）和实验方法（进针点位于坐骨结节中点外侧 3 厘米处，n=20）。我们记录了获得 1.5 mA 初始坐骨神经抽搐和<0.5 mA 抽搐所需的进针次数和时间。
在俯卧位的尸体中，坐骨神经平均距离坐骨结节中点 2.8+/-0.4cm。当从体表标志进针时，通过实验进针点进针的针始终会穿过坐骨神经。相比之下，通过传统进针点进针的针则位于坐骨神经外侧 2.27+/-0.47cm。临床上，我们的实验方法比传统方法需要更少的进针次数来获得坐骨神经抽搐。我们有 55%的患者使用传统方法无法获得抽搐，因此我们将他们转换为实验方法。在最初被分配到实验方法的患者和在传统方法失败后转换为实验方法的患者中，我们有 45%的患者在 1 次进针中获得了第一次坐骨神经抽搐，85%的患者在 3 次进针中获得了第一次坐骨神经抽搐。
我们描述了一种比俯卧位下单侧臀部入路更有效的定位坐骨神经的体表标志。
