Bifrontal Interhemispheric Approach Involving Cutting the Superior Sagittal Sinus for Distal Anterior Cerebral Artery Aneurysms

Abstract Background The unilateral interhemispheric approach is a well-known operative technique for distal anterior cerebral artery (DACA) aneurysms. However, this approach presents several risks, such as postoperative venous infarction due to occasional sacrifice of the parasagittal bridging vein or postoperative frontal lobe damage due to retraction force. To overcome these risks, we used a bifrontal craniotomy with a straight dural incision and cutting of the superior sagittal sinus (SSS). This method helps to overcome the shortcomings of the prior unilateral approach. Methods We retrospectively reviewed 61 aneurysm patients (42 unruptured- and 19 ruptured- A2 and A3 aneurysm) who received clipping surgery through bifrontal interhemispheric approach at our institution between March 2007 and December 2017. This included 35 A2 aneurysms and 27 A3 aneurysms, and the mean size of the aneurysms was 5.45 mm. The modified bifrontal interhemispheric approach involved three steps: bifrontal craniotomy of the centrobasal portion of the frontal bone, ligation and division of the anterior one third of the superior sagittal sinus, and approaching the aneurysm via the interhemispheric space. All patients underwent computed tomography (CT) scans on the third and seventh postoperative days for the evaluation of brain retraction damage or venous infarction. Results Of patients with ruptured aneurysms, 79% had a favorable outcome (Glasgow Outcome Scale 4 or 5) 6 months after primary subarachnoid hemorrhage and all patients with unruptured aneurysms had favorable outcomes. The surgical outcome was strongly related to the preoperative neurologic grade of Hunt and Hess (H-H). Three patients had poor outcomes due to their poor H-H grade on admission (Grade III: 2, IV: 1). In follow up CT scans, venous infarction did not occur in any of our 61 patients. Conclusion The modified bifrontal interhemispheric approach might be a safe and effective method for treating A2,3 aneurysm with relatively good clinical outcome and no surgery-related complications.