Surgical Treatment of Thoracic Spinal Extradural-Intradural Arterio-Venous Malformation: 2-Dimensional Microsurgery

Extradural-intradural arterio-venous malformations (AVMs), also referred to as spinal juvenile metameric (type III) AVM, are extremely rare and are mostly reported as case reports. Most cause a progressive neurological deterioration. They are treated by embolization, surgery, or a combination. Most extradural-intradural AVMs are not completely obliterated after treatment.^1-3 Following institutional review board approval, we present a case of a 71-year-old female, treated by embolization and surgery 40 years before presentation with progressive thoracic myelopathy. As the surgical video contains no patient identifying information or external features permitting identification, the requirement for patient consent for video publication was waived in accordance with the institutional policy. Digital subtraction angiography demonstrated only the paravertebral component, eliminating the option for embolization. Surgical closure using intraoperative monitoring, clipping technique, and indocyanine green (ICG) injection enabled closure of the intradural component visualized by ICG; however, as the preoperative angiography failed to visualize the spinal AVM, postoperative angiography was waived. The postoperative course was uneventful, and intramedullary engorged vessels resolved on the 2-month follow-up magnetic resonance imaging. Angiographically occult intradural AVMs should be explored through a wide surgical exposure with multilevel laminectomy, aided by intraoperative ICG angiography.