{Reference Type}: Journal Article {Title}: Surgical Dissection of a Perimedullary Fistula of Conus Medullaris With Long-Term Follow-Up: 2-Dimensional Operative Video. {Author}: Sorenson TJ;Lanzino G; {Journal}: Oper Neurosurg (Hagerstown) {Volume}: 17 {Issue}: 2 {Year}: Aug 2019 1 {Factor}: 2.817 {DOI}: 10.1093/ons/opy346 {Abstract}: Perimedullary fistulae of the spinal cord are rare vascular lesions that can present with different clinical patterns: hemorrhage, progressive myelopathy due to arterial steal and/or venous congestion, or symptoms due to compression of neural structures by engorged vessels. Treatment consists of surgical excision, endovascular embolization, or a combination of the two. If complete obliteration of the nidus exposes the patient to undue risk of permanent neurological deficits, incomplete obliteration with reduction of the vascular supply is a reasonable compromise to improve clinical symptomatology. Partial devascularization may also alter the natural history by decreasing the risk of further growth and bleeding. In this video we illustrate the case of a patient with a perimedullary fistula of the conus treated with surgical disconnection of the main fistulous component. Partial devascularization resulted in resolution of MRI signal changes and symptoms with documented good clinical and radiological outcome and progressive regression of the residual nidus over six years of follow-up.