Combined Transcranial and Endonasal Approach for Clipping of a Partially Thrombosed Giant Aneurysm of the Lower Basilar Artery

The conventional transcranial approach for treating lower basilar artery aneurysms is challenging because the deep and narrow surgical field limits surgical maneuvering for clipping. We report a case of a 77-year-old female who presented with right hemiparesis caused by a partially thrombosed giant aneurysm in her lower basilar artery. We performed neck clipping and thrombus debulking using a combined transcranial and endonasal approach. This approach enabled us to secure the parent artery from the endonasal side, which is difficult to achieve with the transcranial approach alone. It also allowed for early thrombus removal, thereby widening the surgical field on the transcranial side. Additionally it compensated for the transcranial blind spot by observing the clip tip from the endonasal side. After surgery, the patient required 3 months of rehabilitation for residual right hemiparesis before being discharged. Follow-up imaging revealed a reduction in the size of the partially thrombosed aneurysm. To our knowledge, this is the first report of a combined transcranial and endonasal approach for the treatment of a basilar artery aneurysm. For lower basilar artery aneurysms, this combined approach may offer advantages in achieving safe parent artery control, thrombus debulking, and neck clipping.