ABSTRACT
Brainstem arteriovenous malformations (AVMs) consist of malformations in the midbrain, pons, and medulla; they are either superficial pial AVMs or deep AVMs located within the brainstem parenchyma. These lesions previously were considered to be generally untreatable based on anatomic location. However, over the last two decades, approaches to some of these AVMs that allow treatment with an acceptable risk have been developed and used. Microinstrumentation and the neurosurgical microscope, along with stereotaxis, electrophysiologic monitoring, and preoperative embolization, have enabled neurosurgeons to resect some of these lesions safely. Stereotactic radiosurgery also has allowed treatment of many ‘‘inoperable’’ lesions. While the basic principles of AVM physiology apply to brainstem AVMs, a fundamental knowledge of the anatomy of midline and deep neurologic structures of the posterior fossa is critical for the cerebrovascular surgeon to treat these lesions with minimal risk of patient morbidity.
