Giant Invasive Schwannomas of C1 Root – Technical Challenges and Report of the First Two Cases in Literature

Abstract

Abstract Giant invasive schwannomas (GISs) have been defined as different from other spinal schwannomas. C1 schwannomas are rare and often described with other high cervical tumors. GISs of C1 have not been previously described. Two cases of GIS are reported. In both patients, presenting with myelopathy, the lesions were extradural and intradural with posterior, lateral, and anterior extensions, compressing the cervicomedullary junction (CMJ) and displacing it. The V3-4 segments of the vertebral artery (VA) were closely associated. A posterolateral approach was used to initially expose and debulk the extradural portion of the lesion, which allowed access to the intradural component. The latter was followed anterior and/or posterior to the CMJ and excised completely. The tumors were dissected at the VA. Bleeding from the perivertebral venous plexus was controlled using topical hemostats. A small bit of tumor was left in a blind area anterior to the C1 arch in one patient. There were no complications and both patients improved in the postoperative period. GIS of the C1 are rare lesions in a difficult location. Complex relationships to the CMJ, lower cranial nerves, VA, and bony spine need a careful preoperative understanding of the anatomy and planning of surgery.