title: Herniation of an enlarged middle cerebral artery through a temporal bone defect in association with an arteriovenous malformation.
abstract: We present a previously undescribed variant of the middle cerebral artery (MCA) protruding through a defect in the temporal bone, associated with a large arteriovenous malformation (AVM). The patient, a 59-year-old male, presented with a large right frontoparietal AVM with feeding aneurysms and a recent haemorrhage. Preoperative imaging demonstrated a tortuous right MCA feeder abutting the anterosuperior temporal bone in the region of the pterion. An associated temporal bone defect was visible. The patient underwent a pterional craniotomy for surgical clipping of aneurysms associated with the AVM. On reflection of the temporalis muscle, the MCA branch was transected as it coursed through a defect in the temporal bone. This patient demonstrates that the MCA may deviate from its usual anatomy and herniate through a defect in the skull. Because a pterional craniotomy is such a common surgical approach, knowledge and anticipation of such anatomic variants are essential to avoid catastrophic vascular injury during surgery.
authors.affiliation: Department of Neurosurgery, St. George Hospital, Kogarah, New South Wales, Australia.
authors.forename: Darryl Alan
authors.initials: DA
authors.lastname: Raley
authors.forename: Andrew Stewart
authors.initials: AS
authors.lastname: Davidson
authors.forename: Michael Kerin
authors.initials: MK
authors.lastname: Morgan
mesh_terms: D017542:Aneurysm, Ruptured / Q000601:surgery; D002533:Cerebral Angiography; D003399:Craniotomy; D057510:Endovascular Procedures; D006547:Hernia / Q000473:pathology; D059685:Herniorrhaphy; D006801:Humans; D002532:Intracranial Aneurysm / Q000601:surgery; D002538:Intracranial Arteriovenous Malformations / Q000150:complications / Q000473:pathology* / Q000601:surgery; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000473:pathology* / Q000601:surgery; D011183:Postoperative Complications; D013701:Temporal Bone / Q000002:abnormalities* / Q000473:pathology / Q000601:surgery; D014057:Tomography, X-Ray Computed