Ofiram Elisha, Lonstein John E, Skinner Stan, Perra Joseph H
Twin Cites Spine Center, Minneapolis, MN 55404-4515, USA.
Spine (Phila Pa 1976). 2006 Jun 15;31(14):E464-70. doi: 10.1097/01.brs.0000222122.37415.4d.
A retrospective study of 3 patients with skeletal dysplasia, who had a loss of the evoked potentials during prone positioning before spine surgical intervention.
To bring attention to the potential hazard of neurologic compromise during the positioning of patients with skeletal dysplasia for spine surgery. Recommendations are suggested to prevent the disappearance of intraoperative evoked potentials and, therefore, possible neural injury in these patients.
In a very few published cases, loss or attenuation of monitored potentials has been observed at the time of initial patient positioning. Although patients with skeletal dysplasia might be considered particularly vulnerable to spinal cord injury caused by malpositioning of the head and neck, to our knowledge, no association with lost evoked potentials has previously been described.
Intraoperative transcranial electrical motor-evoked potential and/or somatosensory evoked potential baseline studies were performed after induction in the supine position. These studies were repeated as soon as practicable, after intubation and, again, after the patients were turned prone. The neurophysiologist informed the surgeon that evoked potential change in latency or amplitude met warning criteria. Alteration in the surgical plan resulted in successful spinal surgery in these cases.
In case No. 1, repositioning of the head in flexion was sufficient to return the evoked potentials to normal. In the other two cases, attempts to reposition the patients prone failed, and the procedures were abandoned. In case No. 2, four months after the initial surgery, a halo cast for immobilization and craniocervical decompression were needed before the corrective cervical spine surgery, and in case No. 3, two steps were taken after the initial surgery: 1) trial positioning awake on the surgical table before surgery; and 2) awake postintubation prone positioning on the actual surgery day.
Patients with skeletal dysplasia are susceptible to serious neurologic misadventure when turned to a prone position. Neurophysiologic and/or clinical monitoring of patient positioning should be undertaken, and a plan of intervention, should loss of signal or function occur, must be implemented.
对3例骨骼发育不良患者进行回顾性研究，这些患者在脊柱手术干预前俯卧位时诱发电位消失。
引起人们对骨骼发育不良患者脊柱手术定位过程中神经功能受损潜在风险的关注。提出了一些建议，以防止术中诱发电位消失，从而避免这些患者可能出现的神经损伤。
在极少数已发表的病例中，在患者初始定位时观察到监测电位的消失或衰减。尽管骨骼发育不良患者可能被认为特别容易因头颈部位置不当而导致脊髓损伤，但据我们所知，此前尚未描述过与诱发电位消失的关联。
在仰卧位诱导后进行术中经颅电运动诱发电位和/或体感诱发电位基线研究。在插管后尽快再次进行这些研究，并且在患者转为俯卧位后再次进行。神经生理学家告知外科医生诱发电位潜伏期或波幅的变化符合警告标准。在这些病例中，手术计划的改变导致了脊柱手术的成功。
病例1中，将头部重新屈曲定位足以使诱发电位恢复正常。在另外两例中，将患者重新定位为俯卧位的尝试失败，手术被放弃。病例2中，初次手术后四个月，在进行颈椎矫正手术前需要使用头环固定并进行颅颈减压；病例3中，初次手术后采取了两个步骤：1）术前在手术台上进行清醒试验定位；2）在实际手术日进行插管后清醒俯卧位定位。
骨骼发育不良患者转为俯卧位时易发生严重的神经意外情况。应进行患者定位的神经生理和/或临床监测，并且一旦出现信号或功能丧失，必须实施干预计划。
