Large Vestibular Schwannoma: A Two-Stage Surgery.

Treatment of large vestibular schwannoma (VS) has historically centered on total resection of the lesion. Staged surgery has been used for VS that is highly vascularized, unexpected events during surgery, and thinned and stretched facial nerve with serious adherence causing difficult dissection. We present a case of a patient with a large VS resected through a two-stage surgery through the same retrosigmoid craniotomy.

Transcallosal-Transchoroidal Approach for a Symptomatic Third Ventricular Cavernous Malformation in a Pediatric Patient: Surgical Video.

Cavernous malformations of the third ventricle are rare, deep-seated lesions that pose a formidable surgical challenge due to the rich, surrounding anatomy. Despite the potential morbidity of surgical treatment, the possibility of catastrophic, spontaneous hemorrhage in this location is even more feared and aggressive treatment is warranted, especially if the patient had suffered previous hemorrhages and is currently symptomatic. We demonstrate this approach (Video 1) on a 16-year-old boy who presented with right-sided hemiparesis (power grade 4), intense headaches, difficulties with learning and concentration, and memory loss, mainly affecting short-term memory. The patient had a previous unsuccessful excision at another center 3 months after initial hemorrhage. The absence of hydrocephalus and medial thalamic location favored a modified transcallosal transchoroidal (or subchoroidal) approach. Due to the anatomy of the lesion, no other microsurgical approaches were considered. The surgery at our center (second attempt) was performed 5 months after initial hemorrhage. The head was placed in neutral position, with a slight elevation of the vertex and the midline in a vertical position. A callosotomy had already been performed during the patient's first excision attempt at another center. Although dissection through the tela choroidea is commonly performed medially to the choroidal fissure when one wants to enter the third ventricle, we chose to carefully dissect through this structure laterally, because this thalamic lesion extended almost into the ependymal surface of the third ventricle. This way, the choroidal plexus became a protective cushion for the fornix. On entering the third ventricle, a mulberry-like lesion was readily identified and the cavernoma was located. The central contents of the cavernoma were dissected initially, causing relative deflation of the lesion and more maneuverability to dissect it away from the surrounding structures. Neuromonitoring was used to avoid brainstem injury. Postoperative magnetic resonance imaging showed complete resection with no signs of hemorrhage or ischemia. The patient was discharged on postoperative day 5 with no new neurologic deficits. The patient was also able to return to school after 1 month and showed complete recovery. Unfortunately, neuropsychologic evaluation was unavailable to understand his improvement better. Microsurgical dissection images in this video are a courtesy of the Rhoton Collection, American Association of Neurological Surgeons (AANS)/Neurosurgical Research and Education Foundation (NREF).

Superficial Temporal Artery-Middle Cerebral Artery Bypass Ex Vivo Hybrid Simulator: Face, Content, Construct, and Concurrent Validity.

BACKGROUND: Cerebrovascular bypass surgical procedures require highly developed dexterity and refined bimanual technical skills. To attain such a level of prowess, neurosurgeons and residents have traditionally relied on "flat" models (without depth of field), such as chicken wings, live rats, silicone vessels, and other materials that stray far from the reality of the operating room, albeit more accessible. We have explored the use of a hybrid ex vivo simulator that takes advantage of the availability of placenta vessels and retains the complexity of surgery performed on a human skull to create a more realistic method for the development of cerebrovascular bypass surgical skills. METHODS: Twelve ex vivo simulators were constructed using 3 human placentas and 1 synthetic human skull for each. Face, content, construct, and concurrent validity were assessed by 12 neurosurgeons (6 trained vascular surgeons and 6 general neurosurgeons) and compared with those of other bypass models. RESULTS: The fidelity grade was ranked as low (Linkert scale score, 1-2), medium (score, 3), and high (score, 4-5). The face and content validity of the model showed high fidelity to superficial temporal artery-middle cerebral artery bypass surgery. Construct validity showed that cerebrovascular neurosurgeons had better performance, and concurrent validity highlighted that all surgical steps were present. CONCLUSION: The simulator was found to have strong face and content, construct, and concurrent validity for microsurgical cerebrovascular training, allowing for simulation of all surgical steps of the bypass procedure. The hybrid simulator seems to be a promising method for shortening the bypass surgery learning curve. However, more studies are required to evaluate the predictive validity of the model.

Cavernous Sinus Hemangioma: Surgical Aspects.

Resection of lesions in the cavernous sinus remains a challenge to neurosurgeons due to its complex anatomy. This video (Video 1) presents the most relevant landmarks of the cavernous sinus region, helping to understand the surgical anatomy. A 55-year-old female presented with diplopia, partial ptosis, and facial dysesthesia in the left ophthalmic territory. Magnetic resonance imaging revealed a lesion in the left cavernous sinus. Microsurgical resection was performed through an approach that included a fronto-orbital craniotomy, an extradural clinoidectomy, and intradural resection of the lesion through the anteromedial triangle. This maneuver expands the optic-carotid and carotid-oculomotor space, therefore the operative corridor.1,2 Both the carotid and optic nerves are untethering and can be gently and safely mobilized. The result of the histopathologic study was hemangioma. Despite the complex anatomy and surgical challenges, it is possible to treat lesions in the cavernous sinus region without causing major deficits, mainly in the nonmeningioma tumors. This is why it is important to choose a safe route to the sinus, such as the anteromedial or Parkinson triangle.3.