Resection of a Midbrain Arteriovenous Malformation-A Combined Microsurgical and Endovascular Strategy: 3-Dimensional Operative Video

Brainstem arteriovenous malformations (AVMs) represent 2% to 7% of all brain AVMs.(1-3) Compared with other locations, a greater proportion present with hemorrhage and subsequently have a worse prognosis.(2,4) Surgery has been associated with poor outcomes,(5,6) with parenchymal AVMs associated with higher rates of incomplete resection and morbidity compared with subpial type.7 Concerns over latency from radiosurgery to obliteration after hemorrhage, potential for incomplete obliteration, and risk of adverse radiation effects are cited by proponents of surgery.(6-9) Limited access to the anterior brainstem and difficulty controlling deep feeders add to the complexity of surgery. Previous authors have recommended occlusion in situ for parenchymal brainstem AVMs.(9,10) We present a case showing microsurgical management of a parenchymal midbrain AVM. The patient, 46-year-old man, presented with an acute headache and diplopia following hemorrhage 1 year prior. Examination revealed bilateral ptosis, conjugate upgaze palsy, right abduction paresis, and normal light and accommodation reflexes in keeping with a dorsal midbrain lesion. Magnetic resonance and digital subtraction angiography confirmed a compact midbrain AVM (1.6 cm) extending from the pulvinar thalamus to the right quadrigeminal plate, supplied by posterior thalamoperforating, right posteromedial choroidal and branches of the P3 segment and SCA posteriorly, and drainage by the vein of Galen. Tractography showed displacement of the long tracts. A combination of a posteroanterior microsurgical approach and selective anteroposterior embolization of feeders allowed complete resection with no new deficits. The patient consented to the procedure. We demonstrated that brainstem AVMs can safely be resected in experienced hands, with selective preoperative embolization, use of indocyanine videoangiography, and intraoperative neurophysiological monitoring. The patient signed the Institutional Consent Form, which states that he accepts the procedure and allows the use his images and videos for any type of medical publications in conferences and/or scientific articles.

Automated summary

Brainstem AVMs, comprising 2% to 7% of all brain AVMs, have a worse prognosis due to a higher proportion of hemorrhage. Surgery, despite its associated poor outcomes, is favored by some due to concerns over latency and potential risks of other treatment options. This case demonstrates that in experienced hands, complete resection of brainstem AVMs can be achieved with a combination of selective embolization, neurophysiological monitoring, and microsurgical techniques.