title: Microsurgical and angiographic anatomy of middle cerebral artery aneurysms: prevalence and significance of early branch aneurysms.
abstract: OBJECTIVE
  To determine the prevalence of early branch aneurysms, characterize these lesions angiographically and anatomically, and determine their clinical significance.
  
  
  METHODS
  The authors conducted a retrospective review of 125 consecutive patients with a diagnosis of middle cerebral artery (MCA) aneurysm. Eighty-four patients harboring 100 MCA aneurysms were studied; 41 patients were excluded for lack of adequate imaging or for fusiform morphology of the aneurysm. Demographic characteristics including age, side, sex, subarachnoid hemorrhage, intracerebral hematoma, multiple aneurysms, and type of treatment were obtained.
  
  
  RESULTS
  The average patient age was 57.3 years (range, 29-79 yr); 69 were women and 15 were men. Fifty-eight were right MCA aneurysms and 42 were left aneurysms. Fourteen patients had multiple MCA aneurysms. Thirty-nine of 100 aneurysms were associated with subarachnoid hemorrhage. Twelve of 100 aneurysms were associated with an intracerebral hematoma. The average aneurysm sizes were 9.1 mm overall (range, 2.0-27.0 mm), 12.3 mm for ruptured aneurysms, and 7.5 mm for unruptured. There were 36 M1 bifurcation aneurysms, 39 early frontal branch aneurysms, 18 early temporal branch aneurysms, four lenticulostriate artery aneurysms, and three trifurcation aneurysms.
  
  
  CONCLUSIONS
  In our retrospective review, the majority of MCA aneurysms arose along the M1 segment proximal to the M1 bifurcation. Early frontal branch aneurysms were more common than typical M1 segment bifurcation aneurysms. M1 segment aneurysms arising from early frontal and early temporal branches have distinct anatomic features that impact surgical management and outcome. Understanding the relationship between the recurrent lenticulostriate arteries arising from the proximal segments of these early branches and the aneurysm neck should allow surgeons to avoid many postoperative ischemic complications when dealing with these challenging lesions.
authors.affiliation: Georgia Neurosurgical Institute, Mercer University School of Medicine, Macon, Georgia, USA. jayulm@ganeurosurg.org
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Ulm
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Fautheree
authors.forename: Necmettin
authors.initials: N
authors.lastname: Tanriover
authors.forename: Antonino
authors.initials: A
authors.lastname: Russo
authors.forename: Erminia
authors.initials: E
authors.lastname: Albanese
authors.forename: Albert L
authors.initials: AL
authors.lastname: Rhoton
authors.forename: Robert A
authors.initials: RA
authors.lastname: Mericle
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Lewis
mesh_terms: D000328:Adult; D000368:Aged; D002533:Cerebral Angiography / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000601:surgery; D008297:Male; D008866:Microsurgery / Q000706:statistics & numerical data; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging* / Q000601:surgery; D019635:Neurosurgical Procedures / Q000706:statistics & numerical data; D015995:Prevalence; D014481:United States / Q000453:epidemiology