Department of Anesthesia, Toronto Western Hospital, 399 Bathurst St., Toronto, ON, Canada.
Anesth Analg. 2011 Apr;112(4):982-6. doi: 10.1213/ANE.0b013e31820b5ea3. Epub 2011 Feb 2.
Successful continuous femoral nerve blockade (CFNB) has been associated with the elicitation of a patella motor response during needle and catheter insertion. We evaluated whether a patella motor response is necessary when CFNB is performed in conjunction with ultrasound (US) guidance.
Ninety-eight patients undergoing CFNB (along with sciatic nerve block and spinal anesthetic) for total knee arthroplasty participated in this cohort observational study. Using out-of-plane US guidance alone, the tip of an insulated Tuohy needle was positioned superficial to the midpoint of the femoral nerve visualized in short axis. A nerve stimulator was turned on and the type of motor response (patella versus medial muscle) and minimum stimulating current from the needle were recorded. A stimulating catheter was then inserted and the type of motor response and minimum current from the catheter were recorded. Ten milliliters mepivacaine 2% was injected through the catheter. The primary outcome was sensory block defined as loss of sensation to pinprick on the anterior surface of the distal thigh measured 20 minutes after mepivacaine injection.
Forty-three patients demonstrated a patella motor response, 43 demonstrated a medial motor response, and 12 demonstrated no motor response from the catheter. The proportion of patients with sensory block differed according to motor response from the catheter (patella [98%], medial [91%], and no motor response [75%]; P = 0.02), but there was no significant difference between a patella (98%) and medial (91%) motor response from the catheter (P = 0.58). The proportion of patients with motor block 20 minutes after local anesthetic injection also differed according to motor response from the catheter (patella [95%], medial [77%], and no motor response [67%]; P = 0.03). In addition, there was a significant difference between a patella (95%) and medial (77%) motor response from the catheter (P = 0.01). The mean minimum stimulating currents did not differ between patella and medial motor responses elicited from the catheter (P = 0.06). Postoperative pain and analgesic consumption were similar regardless of the type of motor response from the catheter.
Based on observational data, a patella or medial motor response from the catheter similarly results in sensory block of the anterior thigh when CFNB is performed in conjunction with out-of-plane US guidance.
成功的连续股神经阻滞（CFNB）与在针和导管插入过程中引出髌骨运动反应有关。我们评估了当 CFNB 与超声（US）引导联合使用时，是否需要髌骨运动反应。
98 例接受 CFNB（同时进行坐骨神经阻滞和脊髓麻醉）行全膝关节置换术的患者参与了这项队列观察性研究。单独使用平面外 US 引导，将绝缘 Tuohy 针的尖端置于短轴中可视化的股神经中点的浅层。打开神经刺激器，记录运动反应类型（髌骨与内侧肌肉）和从针获得的最小刺激电流。然后插入刺激导管，并记录导管的运动反应类型和最小电流。通过导管注射 10 毫升 2%甲哌卡因。主要结局是感觉阻滞，定义为注射甲哌卡因后 20 分钟测量的大腿前表面的刺痛感觉丧失。
43 例患者出现髌骨运动反应，43 例出现内侧运动反应，12 例患者无导管运动反应。根据导管运动反应，感觉阻滞的患者比例不同（髌骨[98%]、内侧[91%]和无运动反应[75%]；P=0.02），但髌骨（98%）和内侧（91%）之间无导管运动反应差异无统计学意义（P=0.58）。局部麻醉注射后 20 分钟，运动阻滞的患者比例也根据导管的运动反应而不同（髌骨[95%]、内侧[77%]和无运动反应[67%]；P=0.03）。此外，髌骨（95%）和内侧（77%）之间的导管运动反应差异有统计学意义（P=0.01）。从导管引出的髌骨和内侧运动反应的最小刺激电流平均值无差异（P=0.06）。无论导管的运动反应类型如何，术后疼痛和镇痛药物的消耗均相似。
根据观察数据，当 CFNB 与平面外 US 引导联合使用时，导管引出的髌骨或内侧运动反应同样会导致大腿前侧的感觉阻滞。
