Surgical approaches and nuances for arteriovenous malformations in the posterior fossa

Arteriovenous malformations (AVMs) of the brain are an important cause of hemorrhagic stroke particularly in the young. Posterior fossa AVMs carry a greater risk of hemorrhage than their supratentorial counterparts but also pose unique treatment challenges. Expanding awareness and increasing use of imaging studies have increased rates of posterior fossa AVM diagnosis and treatment. These intriguing AVMs account for 7-15% of brain AVMs. Studies suggest that their risk of morbidity and mortality is greater than that observed with supratentorial AVMs [1,2]. It is helpful to classify posterior fossa AVMs according to their anatomical location: Hemispheric cerebellar AVMs, which constitute approximately 75% of all posterior fossa AVMs, and brainstem AVMs, which are less common but are associated with a worse prognosis in general. A number of factors make posterior fossa AVMs challenging to treat surgically, but success can be achieved with careful patient selection; judicious preoperative embolization; attention to details of positioning, technique, and anatomy; vigilant and attentive neuroanesthesia; and diligent postoperative care and rehabilitation. This chapter will present a global approach to the management of posterior fossa AVMs. The clinical presentation and natural history of these AVMs will be discussed followed by nuances in their management. Finally, in light of the surgical challenges of posterior fossa AVM resection, an overview of surgical techniques and approaches commonly used for the treatment of these lesions will be given. History Clingenstein’s report of the first infratentorial AVM was published in 1908, almost half a century after the initial description of AVMs as a separate pathological entity by Luschka and Virchow [3,4]. In 1932, Olivercrona was the first to perform an excision of a posterior fossa AVM; however, outcomes of the surgical procedure were not documented [4]. Logue and Monckton reported the first posterior fossa AVM excision confirmed by postoperative angiography in 1954 [5]. These authors also described brainstem AVMs and judged them to be inoperable. In 1965, Mount performed the first surgical obliteration of a brainstem AVM but the patient had a poor neurological outcome [6]. In 1972, Green and Vaughan microsurgically removed a posterior fossa AVM, inaugurating the era of microsurgery for AVM treatment [7]. Since then, a significant knowledge base has been accumulated regarding patient selection, technique, and complication avoidance, which has led to improved outcomes [1,2,8,9].