Tumors of the spine are categorized into three classes: 1) intramedullary tumors, 2) intradural extramedullary tumors and 3) extramedullary tumors. Intramedullary tumors are located inside the spinal cord itself. They destroy and/or expand the spinal cord. Extramedullary intradural tumors are outside the spinal cord but inside the dura (the tough fibrous sheath that surrounds the spinal cord). They compress the spinal cord. Extradural tumors are outside the dura, usually associated with the bones (vertebrae) of the spine. They may compress the dura and spinal cord or may destroy the vertebrae, producing spinal instability.

Tumors in each of the three categories may be benign or malignant. The most common intradural extramedullay tumors (meningiomas and schwanommas) are benign, whereas the most common extradural tumors are malignant.

The featured video demonstrates surgical resection of a meningioma. Meningiomas are benign tumors arising from the dura. As they grow and reach a certain size, they compress the spinal cord, producing such symptoms as weakness, paralysis, numbness, incontinence, or pain. The surgical steps shown in this video consist of removing bone (laminectomy) to expose the dura (not shown in video), opening the dura, opening the arachnoid (filmy membrane inside the dura), detaching the tumor from the dura to devascularize and debulk it, dissecting the tumor from the spinal cord and nerve rootlets, removing the tumor, and closing the dura.

Schwanommas are the other common type of intradural extramedullary tumors of the spine. They arise from the covering of the nerves emerging from the spinal cord. They may traverse the dura through the nerve root sleeve and become both intra- and extradural. The following MRI image shows an intradural/extradural schwannoma:

Axial Post-Contrast MRI of Cervical Spine