53 - Thoracolumbar intradural lesion

Abstract

The spinal canal is compartmentalized into an extradural and an intradural space (thecal sac). Spinal intradural tumors occur outside (intradural extramedullary) or inside (intradural intramedullary) of the spinal cord. Meningiomas and nerve sheath tumors such as schwannomas and neurofibromas are the most common histological types of intradural extramedullary tumors. In this chapter, we will discuss the diagnosis and management of spinal schwannomas. Schwannomas usually originate from Schwann cells in the dorsal (sensory) nerve root. Therefore their clinical presentation commonly includes radicular symptoms and local back pain. Sensory changes, myelopathy, sphincter disturbance, and weakness (usually a late finding) can also occur depending on the tumor size and location and the spinal level involved. Fortunately, most schwannomas and other primary intradural tumors are benign and a complete surgical resection is curative. The surgical approach and need for spinal instrumented fusion are dictated by the size of the tumor, spinal level (i.e., the cervicothoracic junction is vulnerable for kyphosis), location within the spinal canal, bony erosion, amount of surgical bony removal (i.e., facetectomy and pediculectomy), preexisting scoliosis or spondylolisthesis, patient’s overall medical condition, and bone quality. A small decompression (hemilaminectomy or laminectomy) without fusion usually suffices for most schwannomas. An initial tumor debulking enables manipulation and circumferentially dissection of the tumor capsule. Intraoperative neurophysiologic monitoring should be used in all cases. The sensory root of tumor origin can be safely sacrificed, but all passing nerve roots, especially motor roots, must be preserved. Overall, an early microsurgical resection of intradural tumors is associated with good outcomes and resolution of preoperative neurological deficits.