Treatment of conus medullaris arteriovenous malformation: the role of microsurgical treatment

OBJECTIVE Conus medullaris arteriovenous malformation (AVM) is rare and challenging to treat. To better define the presentation, prognosis, and optimal treatment of these lesions, the authors present their treatment experiences for conus medullaris AVM. METHODS Eleven patients with AVM of the conus medullaris were identified between March 2013 and December 2021. Among these patients, 7 who underwent microsurgical treatment were included. Patient data, including age, sex, symptoms at presentation, neurological status, radiological findings, nidus depth (mainly pial lesion vs intramedullary lesion), type of treatment, and recurrence at follow-up, were collected. Postoperative angiography was performed in all patients. Spinal cord function was evaluated using the Frankel grade at the time of admission and 1 year after surgery. RESULTS All 7 patients presenting with myeloradiculopathy were treated surgically. Four patients (57.1%) underwent endovascular embolization, followed by resection. The other 3 patients underwent microsurgery only. Complete occlusion was confirmed with postoperative angiography in all patients. Of the 3 patients who were nonambulatory before surgery (Frankel grade C), 2 were able to walk after surgery (Frankel grade D) and 1 remained nonambulatory (Frankel grade C) at 1-year follow-up. CONCLUSIONS Based on the authors’ clinical experiences, the results of multimodal treatment for conus medullaris AVM are good, with microsurgical treatment playing an important role. The microsurgical strategy can differ depending on the location of the nidus, and when possible, good results can be expected through microsurgical resection.