Jacobs Michael J, Mess Werner, Mochtar Bas, Nijenhuis Robbert J, Statius van Eps Randolph G, Schurink Geert Willem H
Department of Vascular Surgery, University Hospital Aachen, The Netherlands.
J Vasc Surg. 2006 Feb;43(2):239-46. doi: 10.1016/j.jvs.2005.09.042.
Paraplegia after thoracoabdominal aortic aneurysm (TAAA) repair mainly occurs in patients with Crawford extent I and II. We assessed the impact of monitoring spinal cord integrity and the subsequent adjusted surgical maneuvers on neurologic outcome in repairs of type I and II TAAAs.
Surgical repair of TAAAs was performed in 112 consecutive patients with extent type I (n = 42) and type II (n = 70) aneurysms. The surgical protocol included cerebrospinal fluid drainage, moderate hypothermia, and left heart bypass with selective organ perfusion. Spinal cord function was assessed by means of monitoring motor evoked potentials (MEPs). Significant decreased MEPs always generated adjustments, including raising distal aortic and mean arterial pressure, reattachment of visible intercostal arteries, or endarterectomy of the excluded aortic segment with revascularization of back bleeding intercostal arteries.
Motor evoked potential monitoring could be achieved in all patients. By maintaining a mean distal aortic pressure of 60 mm Hg, MEPs were adequate in 82% of patients. Increasing distal aortic pressure restored MEPs in all patients. In 19 patients (17%), MEPs decreased significantly during aortic cross-clamping because of critical spinal cord ischemia. MEPs returned in all patients after spinal cord blood flow was re-established except in three patients with type II TAAA in whom MEPs could not be restored, and absent MEPs at the end of the procedure corresponded with neurologic deficit. Delayed paraplegia developed in two patients owing to hemodynamic instability with insufficient mean arterial blood pressure to maintain adequate spinal cord perfusion.
Monitoring MEPs is a highly reliable technique to assess spinal cord ischemia during TAAA repair. A surgical protocol including cerebrospinal fluid drainage, left heart bypass, and monitoring of MEPs can reduce the paraplegia rate significantly. Adjusted hemodynamic and surgical strategies induced by changes in MEPs could restore spinal cord ischemia in most patients, preventing early and late paraplegia in all type I patients. In type II patients, early paraplegia occurred in 4.2% and delayed neurologic deficit in 2.9%. Despite all available measures, complete prevention of paraplegia in type II aneurysms seems to be unrealistic.
胸腹主动脉瘤（TAAA）修复术后截瘫主要发生在克劳福德I型和II型患者中。我们评估了监测脊髓完整性以及随后调整手术操作对I型和II型TAAA修复术中神经功能结局的影响。
连续对112例I型（n = 42）和II型（n = 70）动脉瘤患者进行TAAA手术修复。手术方案包括脑脊液引流、中度低温以及采用选择性器官灌注的左心转流。通过监测运动诱发电位（MEP）评估脊髓功能。MEP显著下降时总会进行调整，包括提高远端主动脉和平均动脉压、重新连接可见的肋间动脉，或对被切除的主动脉段进行动脉内膜切除术并对回流血的肋间动脉进行血管重建。
所有患者均能实现运动诱发电位监测。通过维持平均远端主动脉压60 mmHg，82%的患者MEP正常。提高远端主动脉压后所有患者的MEP均恢复正常。19例患者（17%）在主动脉交叉钳夹期间由于严重脊髓缺血MEP显著下降。除3例II型TAAA患者MEP未能恢复外，所有患者在脊髓血流重建后MEP均恢复，手术结束时MEP消失与神经功能缺损相关。2例患者因血流动力学不稳定导致平均动脉血压不足维持足够的脊髓灌注而发生迟发性截瘫。
监测MEP是评估TAAA修复术中脊髓缺血的高度可靠技术。包括脑脊液引流、左心转流和MEP监测的手术方案可显著降低截瘫发生率。MEP变化引起的血流动力学和手术策略调整可使大多数患者的脊髓缺血恢复，预防所有I型患者发生早期和晚期截瘫。在II型患者中，早期截瘫发生率为4.2%，迟发性神经功能缺损发生率为2.9%。尽管采取了所有可用措施，但完全预防II型动脉瘤患者截瘫似乎不现实。
