Multimodality treatment of conus medullaris arteriovenous malformations: 2 Decades of experience with combined endovascular and microsurgical treatments

BACKGROUND: Conus medullaris arteriovenous malformations (AVMs) are rare, challenging spinal vascular lesions that cause progressive debilitating myeloradiculopathy. Only sporadic reports of conus AVMs have been published. OBJECTIVE: To better define the presentation, prognosis, and optimal treatment of these lesions, we present the first case series of conus AVMs, reflecting over 2 decades of experience with a multimodality endovascular and surgical approach. METHODS: We retrospectively reviewed the charts of 16 patients with a conus AVM evaluated at our institution from 1989 to 2010. For each patient, the following clinical data were collected: age, sex, symptoms, angiographic findings, type of treatment, complications, degree of angiographic obliteration, recurrence at follow-up, and need for re-treatment. Ambulatory status, Frankel Grade, motor function, and bladder/bowel function were assessed before treatment, at discharge, and at last follow-up. RESULTS: All 16 patients were treated. Eight (50%) patients underwent embolization followed by microsurgical resection, and 8 (50%) underwent microsurgical resection only. The rate of complete angiographic obliteration was 88%. At last follow-up (mean, 70 months), 43% of patients neurologically improved, 43% were stable, and 14% worsened in comparison with before treatment. During follow-up, 3 recurrences were detected, including the only 2 instances of long-term neurological decline. In the absence of recurrence, all patients ambulatory before treatment remained ambulatory at follow-up, whereas 75% of the initially nonambulatory patients regained the ability to walk. CONCLUSION: Although conus AVMs are challenging to treat, excellent long-term outcomes are possible with a multimodality approach. Recurrence is associated with long-term neurological decline and calls for close follow-up.