目的 探讨超声定位腰硬联合麻醉技术用于剖宫产手术的临床价值。方法 240例择期行剖宫产手术的产妇，随机分为对照组（传统体表标志定位法）和超声组（超声成像技术定位法），每组120例，准确定位L3～L4间隙后实施腰硬联合麻醉。手术前评估麻醉效果，记录两组产妇的身高、体质量、体质量指数、麻醉前定位所需的时间、两组实施腰硬联合麻醉需要穿刺的次数，测量超声组皮肤至硬膜外腔的距离及两组穿刺针的长度，记录两组产妇硬膜外腔置管时出血、出现神经刺激征象、术后并发硬脊膜穿破后头痛的例数，记录术后第1、3、7日出现腰痛的例数以及术后出现下肢感觉或运动异常的例数。结果 超声组麻醉前定位时间明显长于对照组(P<0.01），腰硬联合麻醉1次成功率高于对照组(P<0.01），麻醉并发症发生率明显低于对照组(P<0.01）。结论 超声成像技术定位L3～L4椎间隙，有助于提高腰硬联合麻醉的1次穿刺成功率，且与麻醉操作相关的并发症发生率低，具有一定的临床应用价值。

Objective To investigate the clinical value of locating the interspinous space by ultrasound imaging technique for combined spinal and epidural anesthesia of cesarean section. Methods Two hundred and forty pregnant women who were going to undergo the cesarean section were randomly divided into the control group (traditional landmark locating method, n=120) and ultrasound group (ultrasound imaging technique locating method, n=120). The space between the third and fourth lumbar vertebrae was properly located and combined spinal and epidural anesthesia was performed. Before the surgery, the anesthesia effect was evaluated for recording height, body mass, body mass index, time for locating before anesthesia, the number of punctures for combined spinal and epidural anesthesia, needle length, and bleeding or nerve irritation symptoms due to the epidural catheter of two groups and the distance of the skin to the epidural space of the ultrasound group. The incidence of post epidural puncture headache and abnormalities of lower extremity sensory or motor after the surgery and the incidence of backache on 1, 3, and 7 d after the surgery were recorded. Results Compared to the control group, the time for locating the interspinous space of the ultrasound group was significantly longer (P<0.01); the success rate of combined spinal and epidural anesthesia performed by one puncture was significantly higher (P<0.01); and the incidence of anesthesia related complications was significantly lower (P<0.01). Conclusion Locating the space between the third and fourth lumbar vertebrae by ultrasound imaging technique is helpful for improving the success rate of combined spinal and epidural anesthesia performed by one puncture and decreasing anesthesia related complications and has certain value in clinical applications.