Department of Neurosurgery, Medical University of Vienna, Austria.
J Neurosurg Spine. 2012 Feb;16(2):114-26. doi: 10.3171/2011.10.SPINE11109. Epub 2011 Nov 25.
Thoracic idiopathic spinal cord herniation (TISCH) is a rare neurological disorder characterized by an incarceration of the spinal cord at the site of a ventral dural defect. The disorder is associated with clinical signs of progressive thoracic myelopathy. Surgery can withhold the natural clinical course, but surgical repair of the dural defect bears a significant risk of additional postoperative motor deficits, including permanent paraplegia. Intraoperative online information about the functional integrity of the spinal cord and warning signs about acute functional impairment of motor pathways could contribute to a lower risk of permanent postoperative motor deficit. Motor evoked potential (MEP) monitoring can instantly and reliably detect dysfunction of motor pathways in the spinal cord. The authors have applied MEPs during intraoperative neurophysiological monitoring (IOM) for surgical repair of TISCH and have correlated the results of IOM with its influence on the surgical procedure and with the functional postoperative outcome.
The authors retrospectively reviewed the intraoperative neurophysiological data and clinical records of 4 patients who underwent surgical treatment for TISCH in 3 institutions where IOM, including somatosensory evoked potentials and MEPs, is routinely used for spinal cord surgery. In all 4 patients the spinal cord was reduced from a posterior approach and the dural defect was repaired using a dural graft.
Motor evoked potential monitoring was feasible in all patients. Significant intraoperative changes of MEPs were observed in 2 patients. The changes were detected within seconds after manipulation of the spinal cord. Monitoring of MEPs led to immediate revision of the placement of the dural graft in one case and to temporary cessation of the release of the incarcerated spinal cord in the other. Changes occurred selectively in MEPs and were reversible. In both patients, transient changes in intraoperative MEPs correlated with a reversible postoperative motor deficit. Patients without significant changes in somatosensory evoked potentials and MEPs demonstrated no additional neurological deficit postoperatively and showed improvement of motor function during follow-up.
Surgical repair of the dural defect is effected by release and reduction of the spinal cord and insertion of dural substitute over the dural defect. Careful monitoring of the functional integrity of spinal cord long tracts during surgical manipulation of the cord can detect surgically induced impairment. The authors' documentation of acute loss of MEPs that correlated with reversible postoperative motor deficit substantiates the necessity of IOM including continuous monitoring of MEPs for the surgical treatment of TISCH.
特发性胸段脊髓脊膜膨出（TISCH）是一种罕见的神经系统疾病，其特征为脊髓在腹侧硬脑膜缺损部位嵌顿。该疾病与进行性胸段脊髓病的临床体征相关。手术可以阻止自然临床病程，但硬脑膜缺损的手术修复存在显著的术后运动功能障碍风险，包括永久性截瘫。术中有关脊髓功能完整性的即时信息以及关于运动通路急性功能损伤的警告信号，可能有助于降低永久性术后运动功能障碍的风险。运动诱发电位（MEP）监测可以即时、可靠地检测脊髓运动通路的功能障碍。作者在 3 家机构应用 MEP 进行术中神经生理监测（IOM），以修复 TISCH，并将 IOM 结果与手术过程和术后功能结果相关联。
作者回顾性分析了在 3 家机构接受 TISCH 手术治疗的 4 例患者的术中神经生理数据和临床记录，这 3 家机构常规在脊髓手术中应用 IOM，包括体感诱发电位和 MEP。在所有 4 例患者中，脊髓均通过后路复位，硬脑膜缺损采用硬脑膜移植物修复。
所有患者均可行 MEP 监测。2 例患者出现显著的术中 MEP 变化。脊髓操作后几秒钟内即检测到变化。MEP 监测导致 1 例患者的硬脑膜移植物位置立即修正，另 1 例患者的脊髓嵌顿释放暂时停止。变化选择性地出现在 MEP 中，并且是可逆转的。在这 2 例患者中，术中 MEP 的变化与术后可逆转的运动功能障碍相关。体感诱发电位和 MEP 无显著变化的患者术后无额外神经功能缺损，并在随访中表现出运动功能改善。
硬脑膜缺损的手术修复通过脊髓的释放和复位以及硬脑膜替代物在硬脑膜缺损处的插入来完成。在脊髓操作过程中仔细监测长束脊髓的功能完整性，可以检测到手术引起的损伤。作者记录到与术后运动功能障碍可逆转相关的 MEP 急性丧失，证实 IOM 包括对 TISCH 手术治疗的持续 MEP 监测的必要性。
