Anterior Dorsal Root Entry Zone Approach in the Treatment of Spinal Intramedullary Glioma.

ABSTRACT

Surgical removal of lateral or ventrolateral spinal intramedullary gliomas remains a challenge. For lateral or ventrolateral tumors, the dorsal root entry zone (DREZ) myelotomy (equivalent to dorsolateral sulcus approach) and the posterior midline myelotomy would require dissection of the posterolateral tract or posterior column tracts and cause neurologic dysfunction. In Video 1, we introduce a novel approach in which myelotomy was performed anterior to DREZ. The spinal cord was entered between the DREZ and dorsal spinocerebellar tracts, and the surgical path was posterior to the lateral corticospinal tract. Thus no important spinal cord tracts were damaged. The patients with intramedullary glioma depicted in this video had no new neurologic dysfunction postoperatively. This approach has also been reported in treating intramedullary cavernous malformations.1 Compared with the DREZ approach, myelotomy anterior to the DREZ has 2 advantages. First, the blood vessels anterior to DREZ are always sparser than the posterolateral sulcus. Second, the injury of the somatosensory tract and posterior horn of the spinal cord caused by the dorsolateral sulcus approach can be avoided. Special technique details for this approach are as follows 1) Myelotomy anterior to DREZ can be optional for selective cases of lateral or ventrolateral intramedullary tumor. 2) It is difficult for cervical intramedullary tumors because the cervical dorsal roots always cover the area of the anterior DREZ. 3) It is useful for a multisegment tumor to cut the dentate ligament. 4) Hemilaminectomy can be used in selective cases for this approach.