Subtemporal, Transapical, and Transcavernous Approach to Clip Low-Lying Basilar Tip Aneurysm: 2-Dimensional Operative Video

Basilar tip aneurysm clipping is technically challenging because of the depth of operative corridor, rarity in presentation, and important perforators supplying deep, critical structures. Two major approaches to basilar tip aneurysms include (1) a frontotemporal (transorbital) trans-sylvian approach for most aneurysms and (2) a modified subtemporal approach for aneurysms with low-lying necks. A 53-yr-old woman presented to our institution with a large unruptured basilar tip aneurysm notable for a low, broad neck (6.4 mm). After discussion of risks and benefits of endovascular vs surgical options, the patient consented to operative intervention. She underwent a right frontotemporal craniotomy with zygomatic osteotomy, intradural petrous apicectomy, elective sectioning of the fourth cranial nerve (CN IV), and intracavernous removal of the dorsum sellae and posterior clinoid process to provide more space for aneurysm dissection. After temporary clipping of the basilar artery, the perforating arteries were dissected free from the aneurysm and the aneurysm occluded with 2 fenestrated clips. Important technical nuances of the approach include (1) achieving ample working room for temporary occlusion aneurysm dissection, (2) careful dissection of the perforators and contralateral P1, and (3) utilization of 2 fenestrated clips to accommodate and preserve the ipsilateral P1 segment. Postoperative angiogram showed complete aneur-ysmal occlusion. Postoperatively, the patient demonstrated mild cognitive impairment and a right CN IV palsy. At 6-wk follow-up, cognition recovered to normalcy. More recently, at 12-mo follow-up, the patient noted intermittent diplopia. Formal neuro-ophthalmologic assessment confirmed persistence of a CN IV palsy treated with prism lenses but no other neurological deficits.

Hydrocephalus Revealed by Relapsing Bilateral Fourth Cranial Nerve Palsy

Introduction: Uni- or bi-lateral fourth cranial nerve palsy due to hydrocephalus and/or after VPS placement is a very rare oculomotor manifestation. We report a case of relapsing bilateral fourth nerve palsies demonstrating recurring hydrocephalus. We reviewed the literature (table1) in order to inform the clinician about the clinical assessment, the past medical history and the radiological findings that prompt research for this peculiar entity and to avoid misdiagnoses like palsies of the sixth cranial nerve. Diagnosis, intervention and outcome: The patient presented with recurrence of diplopia in reading position, partially resolved after a second VPS placement. A diagnosis of bilateral fourth nerves palsies was done after complete neuro-ophthalmological evaluation. A close follow-up demonstrated fluctuating level of diplopia by changing VPS valve resistance. An optimal placement of the VPS offered reduction and stability of diplopia. A final strabismus surgery was necessary to obtain complete symptoms release.