Abstract:

Objective　To investigate the imaging anatomical characteristics of intramedullary ependymoma in cervical spinal cord and formulate appropriate surgical strategy.　Methods　Tumors in 26 patients with intramedullary ependymoma in the cervical spinal cord were categorized by analyzing the pre-operative magnetic resonance imaging (MRI) characteristics and the compressed alteration of the spinal cord,and removed with assistance from real time neuro-electrophysiological monitoring.　Results　The tumors were classified into three types based on their morphological changes and the anatomical relationship between the spinal cord and the tumor : Type I: Solid tumor with syringomyelia or cyst；Type II: Solid tumor；Type III: Tumor tubercle in the cyst. For type I, tumors were removedstarting from operating at the posteriormedian sulcus at the border of the poles of the tumor and the syringomyelia or cyst,or at the center of the tumors. For type II,tumors were resected starting from operating at the posterior median sulcus at the center of the tumors, and for type III, starting from operating at the posterior median sulcus at the point close to the tumor tubercles.When the introperative neuro-electrophysiological monitor indicated a 50% reduction of the amplitude or a 10% delay of the latency of somatosensory evoked potential (SEP), andor the amplitude of motor evoked potential (MEP) for the target muscles dropped to 20%, surgical procedures should be suspended for its recovery. The final pathological diagnosis of all the cases was intramedullary ependymoma. Post-operative MRI indicated of all the cases, 23 were total removed, 3 partially, without death during surgery. Post-operative symptoms were significantly improved in 23 patients, partially in 2 and deteriorated in 1.　Conclusion　Classification based on pre-operative MRI characteristics and formulation of appropriate surgical strategy may be helpful for total removal of intramedullary ependymomain the cervical spinal cord and reduction of injury of spinal cord.

Key words: Intramedullary ependymoma, Spinal Tumor, Magnetic resonance imaging, Microsurgical operation