Right Pretemporal-Transsylvian Approach for Resection of a Midbrain Cavernous Malformation: 3-Dimensional Operative...

Area of Science:

• Neurosurgery
• Vascular Neurosurgery
• Cerebrovascular Surgery

Background:

• Brainstem cavernous malformations (CMs) are rare cerebrovascular lesions, comprising 15-18% of intracranial CMs.
• These lesions in the posterior fossa present significant surgical challenges due to their deep location and proximity to critical neurovascular structures.

Purpose of the Study:

• To demonstrate the surgical resection of a pontomesencephalic cavernous malformation.
• To highlight the utility of the pretemporal approach via the oculomotor-tentorial triangle (OTT) for accessing brainstem lesions.

Main Methods:

• A 49-year-old female patient with a symptomatic pontomesencephalic CM underwent surgical resection.
• A right orbitozygomatic craniotomy and pretemporal-transsylvian approach were utilized, involving Sylvian fissure splitting and temporal lobe retraction to expose the OTT.
• The CM was accessed deep to the posterior cerebral and superior cerebellar arteries within the OTT and resected using an intracapsular technique.

Main Results:

• Postoperative imaging confirmed gross total resection of the 25-mm pontomesencephalic CM.
• Initial postoperative deficits included right CN III palsy and left hemiparesis, which resolved completely by 6-month follow-up.

Conclusions:

• The oculomotor-tentorial triangle (OTT) serves as a crucial surgical workspace for accessing ventrolateral pontomesencephalic and midbrain lesions.
• The pretemporal-transsylvian corridor provides effective access to the OTT, facilitating the safe resection of challenging brainstem cavernous malformations.