Considerations in the surgical treatment of superior-wall type aneurysm at the proximal (M1) segment of the middle cerebral artery

Summary

Objective. To present our experience and analyze the risks of neck clipping for superior-wall type aneurysms of the proximal segment of the middle cerebral artery (M1-Sup aneurysm).

Methods. Of 14 patients with M1-Sup aneurysms, 4 suffered postoperative infarctions in the territory of the lenticulostriate arteries (LSA) or fronto-orbital arteries. We re-examined our intraoperative findings and clinical records in an effort to identify possible causes.

Results. The patency of the LSA was confirmed at the end of surgery in all 14 cases. We posit that temporary occlusion of the LSA by a permanent clip resulted in delayed obstruction of the LSA in 3 patients. Other possibilities we considered were relatively long temporary occlusion of the M1, slipping of the clips and twisting of the clip blades after release of the brain retractors.

Conclusion. M1-Sup aneurysms are some of the most complicated aneurysms; they carry the risk of perforator injury during neck clipping. Surgical considerations to avoid perforator injury are discussed.