在麻醉领域，超声引导外周神经阻滞［1］和血管穿刺［2］ 目前已得到广泛应用，但超声引导椎管内麻醉的发展比较缓慢，因为在行腰椎管的超声扫查时，目标组织的位置相对比较深，骨性组织阻碍了超声束进入椎管，导致获得的声窗较窄［3］。尽管存在技术上的困难，随着超声设备和成像技术的提高，近年来已有一些研究应用超声技术辅助确定椎间隙水平、预测穿刺针进针深度和穿刺的困难程度［4-7］，这些研究的对象主要为孕产妇和肥胖患者［8-10］，也有用于脊柱畸形［11］和脊柱手术史患者［12-13］的个案报道。本文报道1例既往行L3、L4椎弓根螺钉内固定，在超声引导下成功实施椎管内麻醉的病例。

A patient with previous L3-4 posterior lumbar interbody fusion, pedicle screws instrumentation and L3-4 decompression, was scheduled for left total hip arthroplasty. Two years ago, due to poor landmarks palpation, the patient experienced a failed lumbar puncture after multiple attempts before herniorrhaphy. His plain radiography showed bilateral partial laminectomy at L3-4 level, and between L3 and L4, two posterior pedicle screws connected by metal rods on both sides. This time, we used ultrasound to locate L4-5 interlaminar space in paramedian sagittal oblique view and identified the spine midline by transverse interlaminar view before puncture. According to this information, L4-5 puncture point was verified and the combined spinal-epidural anesthesia was performed in a paramedian approach. After withdrawing clear cerebral spinal fluid, 15 mg hyperbaric bupivicaine was injected into intrathecal space. An epidural catheter was then inserted into the epidural space. The sensory block level was fixed at T10 to S within 10 minutes. Intraoperatively, the patient received 10 mL 2% (mass fraction) lidocaine through the epidural catheter in total. The surgery was uneventful. No neurologic complication was observed after the surgery. This case report demonstrates that ultRASound imaging can provide useful information for neuraxial needle placement and can be a valuable tool in managing patients with anatomical change around the spine.