Department of Anesthesiology, Hospital Clinic, University of Barcelona, Barcelona, Spain.
Anesthesiology. 2011 Sep;115(3):589-95. doi: 10.1097/ALN.0b013e3182276d10.
Intraneural injection during nerve-stimulator-guided sciatic block at the popliteal fossa may be a common occurrence. Although intraneural injections have not resulted in clinically detectable neurologic injury in small studies in human subjects, intraneural injections result in postinjection inflammation in animal models. This study used clinical, imaging, and electrophysiologic measures to evaluate the occurrence of any subclinical neurologic injury in patients with intraneural injection during sciatic popliteal block.
Twenty patients undergoing popliteal block were enrolled; 17 patients completed the study protocol. After tibial nerve response was achieved by nerve stimulation (0.3-0.5 mA; 2 Hz; 0.1 ms), 20 ml mixture of mepivacaine (1.25%) and radiopaque contrast (2 ml) were injected. Location and spread of the injectant were assessed by ultrasound measurements of the sciatic nerve area before and after injection, and by computed tomography. In addition to clinical neurologic evaluations, serial electrophysiologic studies (nerve conduction and late response studies using predefined criteria) were performed at baseline and at 1 week and 3 weeks after the block for signs of subclinical neurologic dysfunction.
Sixteen injections (94%, 95% CI: 71-100%) met criteria for an intraneural injection. Postinjection nerve area on ultrasound increased by 45% (95% CI: 29-58%), P < 0.001. Computed tomography demonstrated fascicular separation in 70% (95% CI: 44-90%), air within the nerve in 29% (95% CI: 10-56%), contrast along bifurcations in 65% (95% CI: 38-86%), and concentric contrast layers in 100% (95% CI: 84-100%). Neither clinical nor electrophysiologic studies detected neurologic dysfunction indicating injury to the nerve.
Nerve-stimulator-guided sciatic block at the popliteal fossa often results in intraneural injection that may not lead to clinical or electrophysiologic nerve injury.
在腘窝神经刺激器引导下坐骨神经阻滞时，可能会发生神经内注射。尽管在人类受试者的小研究中，神经内注射并未导致临床上可检测到的神经损伤，但在动物模型中，神经内注射会导致注射后炎症。本研究使用临床、影像学和电生理测量来评估在坐骨神经腘窝阻滞时发生神经内注射的患者是否存在亚临床神经损伤。
共纳入 20 名接受腘窝阻滞的患者；17 名患者完成了研究方案。在通过神经刺激（0.3-0.5 mA；2 Hz；0.1 ms）获得胫神经反应后，注射 20 ml 甲哌卡因（1.25%）和不透射线对比剂（2 ml）的混合物。在注射前后通过超声测量坐骨神经区域评估注射剂的位置和扩散，并通过计算机断层扫描进行评估。除了临床神经评估外，还在基线和阻滞后 1 周和 3 周时使用预设标准进行连续电生理研究（神经传导和晚期反应研究），以寻找亚临床神经功能障碍的迹象。
16 次注射（94%，95%置信区间：71-100%）符合神经内注射标准。超声检查显示注射后神经面积增加 45%（95%置信区间：29-58%），P<0.001。计算机断层扫描显示 70%（95%置信区间：44-90%）存在束分离，29%（95%置信区间：10-56%）存在神经内空气，65%（95%置信区间：38-86%）存在分支处对比剂，100%（95%置信区间：84-100%）存在同心对比层。临床和电生理研究均未发现表明神经损伤的神经功能障碍。
在腘窝神经刺激器引导下的坐骨神经阻滞常导致神经内注射，但可能不会导致临床或电生理神经损伤。
