Anterior Clinoidectomy: Intradural Step-by-Step En Bloc Removal Technique.

OBJECTIVE: Anterior clinoidectomy is an important and essential skill for skull base and cerebrovascular neurosurgeons. We present a 1-piece intradural anterior clinoidectomy, providing a step-by-step description of the technique, independently of anatomic variations. METHODS: Between 2014 and 2020, 128 patients (119 women and 9 men; average age, 54.6 years) underwent intradural anterior clinoidectomy during microsurgical clipping of carotid-ophthalmic aneurysms. RESULTS: The anterior clinoid process continues medially with the planum sphenoidale, over the optic nerve, laterally with the lesser wing of the sphenoid bone, and inferiorly with the optic strut, which is always found anteriorly to the clinoid segment of the internal carotid artery, and separates the optic canal from the superior orbital fissure. The proposed anterior clinoidectomy followed, one after the other, these 3 fixation points for the detachment of the anterior clinoid process. The main indication for intradural anterior clinoidectomy was the management of vascular lesions around paraclinoid (clinoidal and ophthalmic) segments of the internal carotid artery. Complications of the procedure included injury to the internal carotid artery or the ophthalmic artery, thermal damage to the optic nerve, and invasion of the sphenoid sinus or a pneumatized anterior clinoid process, which could lead to postoperative cerebrospinal fluid leakage. CONCLUSIONS: The anterior clinoidectomy technique described here minimizes the drilling surface for detachment of the anterior clinoid process and reduces operative time as well as the amount of bone dust produced by drilling. It also precisely delineates the localization of the optic strut, preventing carotid or optic nerve damage.

Interhemispheric transcallosal transforaminal approach for decompression of a giant superior cerebellar artery thrombosed aneurysm: Three-dimensional operative video.

BACKGROUND: Giant brain aneurysms account for approximately 5% of all intracranial aneurysms, often presenting with intraluminal thrombosis that causes a mass effect in surrounding neural structures. Although its exact growing mechanism remains unknown, they have to be treated. Despite the most recent advances in neurosurgical fields, the best treatment modality remains unknown and surgery of giant superior cerebellar artery (SCA) aneurysms still is a challenge even for the most experienced neurosurgeons, due to their deep location, surrounding perforating vessels, and intraluminal thrombosis. CASE DESCRIPTION: In this video, we present the case of a 65-year-old woman with progressive hemiparesis and paresis of low cranial nerves. The symptoms were caused by a giant aneurysm located in the origin of the SCA. Despite endovascular embolization of the aneurysm and placement of a flow diverter stent, the aneurysm increased in size causing symptoms progression. In that scenario, we decided to perform a microsurgical decompression of the aneurysm thrombus and coagulation of the vasa vasorum, to reduce the mass effect and prevent the aneurysm from keep growing. CONCLUSION: Through an extensive description of the surgical anatomy, we illustrate an interhemispheric transcallosal transforaminal approach, with the removal of anterior thalamic tubercle to widely expose the aneurysm dome. The surgery was successfully performed, and the patient symptoms improved. The patient signed the Institutional Consent Form, which allows the use of her images and videos for any type of medical publications in conferences and/or scientific articles.

Microsurgical Resection of a Left Supramarginal Gyrus AVM Causing Radionecrosis.

Late radiation necrosis is a rare entity presenting in 2.2% to 9% of radiation-treated arteriovenous malformations (AVMs). It occurs by a mean of 3 years following treatment. There are few reports in the literature of radionecrosis and solid lesions treated with surgery.1-4 To the authors' knowledge, this case has the longest interval between radiosurgery and the presentation of cerebral necrosis. In this surgical video, we present the case of a 51-year-old female with a left supramarginal gyrus AVM that received radiosurgery with gamma knife; after 20 years, she began having seizures and aphasia. The magnetic resonance imaging scan revealed a lesion simulating an intra-axial tumor causing important edema and mass effect. Medical treatment was given including high-dose steroids without success, therefore microsurgery was performed. The surgery was presented in a step-by-step basis and correlation was performed with the involved adjacent anatomy, to illustrate the anatomy of the approach and surgical landmarks. The patient's symptoms resolved completely, and the postoperative magnetic resonance imaging scan showed complete resection and resolution of the edema. The histopathological findings were consistent with a radionecrosis and AVM. The patient signed the Institutional Consent Form, which states that she accepts the procedure and allows the use of her images and videos for any type of medical publications in conferences and/or scientific articles.