gms | German Medical Science

Objective: Surgery of large arteriovenous malformations represents one of the most challenging tasks confronting neurosurgeons. Especially those situated in motor areas are difficult to treat due to the risk of producing severe functional impairment. Surgical indication for patients harboring AVMs in these locations is still a controversial matter, and the majority of cases are thus treated conservatively. In the present report the safety of the surgical treatment is discussed in light of the technical development in Neurosurgery.

Methods: We evaluated retrospectively 13 patients with AVMs located in motor brain areas submitted to surgical treatment from January 2006 to February 2009. Preoperative evaluation involved conventional MRI, DSA, 3D angio-CT, functional MRI, and 3D tractography. Operations were performed under continuous electrophysiological monitoring and guided by neuro-navigation. Intraoperative direct brain stimulation served to confirm the preoperative anatomo-functional data, and electrophysiological monitoring helped safe occlusion of AVM feeders. Clinical outcome was evaluated using the Modified Rankin Scale.

Results: Among 13 studied cases, 7 lesions were located in the primary motor cortex, 4 in the insular cortex, involving the internal capsule and/or basal ganglia, and 2 in the posterior fossa involving partially the brainstem. Mean age was 42±22 years. Eight patients were diagnosed after bleeding, among them 3 were admitted in the acute phase. Total resection was achieved in 11 cases, whereas partial resection was in 2. A significant reduction of MEPs to 10–20% of the initial values was not associated with a bad recovery of motor function, but disappearance of potentials was related to a bad outcome. Follow-up was 6.3 (1–23) months, ten out of 13 patients were asymptomatic or presented minor neurological deficits, only two cases deteriorated postoperatively with high grade paresis, but were able to walk in the long-term. One case died due to complications of the intracerebral bleeding preoperatively.

Conclusions: Our data supports the concept that the recent advances in functional imaging and electrophysiological monitoring have contributed significantly to reduce the perioperative morbidity in the latest years. Based on our series, we consider that surgery for large AVMs located in motor areas can be safely performed and should be considered for some selected cases.