-Original-

Utility of the Orbitocranial Approach for Clipping of Anterior Communicating Artery Aneurysms: Significance of Dissection of the Interhemispheric Fissure and the Sylvian Fissure

Takayuki Mizunari^1,2, Yasuo Murai¹, Shiro Kobayashi^1,2, Shigeru Hoshino^1,2 and Akira Teramoto¹

¹Department of Neurosurgery, Graduate School of Medicine, Nippon Medical School
²Department of Neurosurgery, Neurosurgical Institute, Nippon Medical School Chiba Hokusoh Hospital

Objective: To investigate the importance of sufficient dissection of the interhemispheric and sylvian fissures, an orbitocranial approach was used for clipping of ruptured anterior communicating artery aneurysms.
Patients and Methods: From January 1998 through March 2009, 41 patients underwent surgery for subarachnoid hemorrhage caused by rupture of an anterior communicating artery aneurysm. Their mean age was 58.4 years, with a range of 37 to 84 years. The preoperative World Federation of Neurosurgical Societies grade was I to III in 32 patients and IV to V in 9 patients. The direction of the aneurysm was upward in 23 patients, forward in 14 patients, and backward in 4 patients. Seven patients had a large aneurysm.
Results: All patients underwent surgery during the acute stage following the subarachnoid hemorrhage (day 0-2). A right orbitocranial approach was used for most patients, but a left orbitocranial approach was used for 9 patients because of the presence of a complicated aneurysm and the positional relationship of the left-right A2 segment. In 12 patients, external decompression was performed. The outcome, using the Glasgow Outcome Scale, was good recovery in 24 patients, moderately disabled in 8 patients, and severely disabled in 4 patients, and 5 patients died. Temporary eye movement disorders developed after surgery in 5 patients but resolved in all patients within 2 months. No patients had olfactory disturbance.
Discussion: Using the orbitocranial approach and sufficient dissection of the interhemispheric and sylvian fissures, we could secure a broad field of vision and surgical field, which contributed to a safe operation. The only postoperative complication caused by the surgical approach was temporary eye movement disorder. Thus, for some patients with aneurysms of the anterior communicating artery, the orbitocranial approach contributes to improved outcomes.

J Nippon Med Sch 2011; 78: 77-83

Keywords
cerebral aneurysm, anterior cerebral artery, approach, clipping

Correspondence to
Takayuki Mizunari, MD, Department of Neurosurgery, Nippon Medical School Chiba Hokusoh Hospital, 1715 Kamagari, Inba-mura, Inba-gun, Chiba 270-1694, Japan
tmizunari@gmail.com

Received, June 10, 2010
Accepted, November 29, 2010