Deep arteriovenous malformations in the basal ganglia, thalamus, and insula: Microsurgical management, techniques, and results

Background: Arteriovenous malformations (AVMs) in the basal ganglia, thalamus, and insula are considered inoperable given their depth, eloquence, and limited surgical exposure. Although many neurosurgeons opt for radiosurgery or observation, others have challenged the belief that deep AVMs are inoperable. Further discussion of patient selection, technique, and multimodality management is needed. Objective: To describe and discuss the technical considerations of microsurgical resection for deep-seated AVMs. Methods: Patients with deep AVMs who underwent surgery during a 14-year period were reviewed through the use of a prospective AVM registry. Results: Microsurgery was performed in 48 patients with AVMs in the basal ganglia (n = 10), thalamus (n = 13), or insula (n = 25). The most common Spetzler-Martin grade was III-(68%). Surgical approaches included transsylvian (67%), transcallosal (19%), and transcortical (15%). Complete resection was achieved in 34 patients (71%), and patients with incomplete resection were treated with radiosurgery. Forty-five patients (94%) were improved or unchanged (mean follow-up, 1.6 years). Conclusion: This experience advances the notion that select deep AVMs may be operable lesions. Patients were highly selected for small size, hemorrhagic presentation, young age, and compactness-factors embodied in the Spetzler-Martin and Supplementary grading systems. Overall, 10 different approaches were used, exploiting direct, transcortical corridors created by hemorrhage or maximizing anatomic corridors through subarachnoid spaces and ventricles that minimize brain transgression. The same cautious attitude exercised in selecting patients for surgery was also exercised in deciding extent of resection, opting for incomplete resection and radiosurgery more than with other AVMs to prioritize neurological outcomes.