• Journal of Korean Neurosurgical Society
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• v.29 no.1
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• pp.118-125
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• 2000

Objective : Trigeminal neurinomas are rare tumors that may locate in the middle fossa or posterior fossa and straddled both the middle and posterior fossa, according to their origin in the nerve complex. The aim of this study was to analyze the clinical presentation, operative approaches employed and outcome in 15 patients who were treated surgically, with special emphasis on surgical approach. Method : Between 1994 and 1998, a total of fifteen patients were histopathologically identified as neurinomas originating from the trigeminal nerve complex at the tumor clinic in the neuroscience center of the our university. Results : The surgical approach to these tumors depends on their anatomical location and tumor size. Six patients had tumors confined to the middle fossa, five patients had tumors limited to the posterior fossa, and four patients both in middle and posterior fossa components of their tumors. Nine neurinomas were removed via the conventional approach(pterional, subtemporal, suboccipital) and six were excised using skull base approach(transzygomatic subtemporal, orbitozygomatic, transpetrosal). Total resection of the tumor was possible in 10 cases. Total resection of tumor was accomplished in 83% of patients following skull base approach compared with 56% of patients following conventional approach. The surgical outcome was excellent or good in 13 cases, fair in one and, poor in one. There was no operative death. In the immediate postoperative period, aggravation of preoperative facial hypesthesia and 6th cranial nerve palsy were common. Although, these deficits were generally transient, eight patients remained with some degree of trigeminal hypesthesia, two had facial weakness, one neurotrophic keratitis, one diplopia, and one mastication difficulty. Conclusion : Surgical approach to the trigeminal neurinoma depends on the tumor location and tumor size. Skull base approach provides more complete tumor excision without increased morbidity compared to conventional approach. Surgeons have to be meticulous in order to reduce postoperative complication.

• Journal of Korean Neurosurgical Society
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• v.67 no.4
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• pp.411-417
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• 2024

Objective : To confirm the usefulness of the extradural anterior clinoidectomy during the clipping of a low riding posterior communicating artery (PCoA) aneurysm through cadaver dissection. Methods : Anatomic measurements of 12 adult cadaveric heads (24 sides total) were performed to compare the microsurgical exposure of the PCoA and internal carotid artery (ICA) before and after clinoidectomy. A standard pterional craniotomy and transsylvian approach were performed in all cadavers. The distance from the ICA bifurcation to the origin of PCoA (D1), pre-anterior clinoidectomy distance from the ICA bifurcation to tentorium (D2), post-anterior clinoidectomy distance from the ICA bifurcation to tentorium (D3), pre-anterior clinoidectomy distance from the tentorium to the origin of PCoA (D4) and post-anterior clinoidectomy distance from the tentorium to the origin of PCoA (D5) and the distance of the ICA obtained after anterior clinoidectomy (D6) were measured. We measured the precise thickness of the blade for the Yasargil clip with a digital precision ruler to confirm the usefulness of the extradural anterior clinoidectomy. Results : Twenty-four sites were dissected from 12 cadavers. The age of the cadavers was 79.83±6.25 years. The number of males was the same as the females. The space from the proximal origin of the PCoA to the preclinoid-tentorium (D4) was 1.45±1.08 mm (max, 4.01; min, 0.56). After the clinoidectomy, the space from the proximal origin of the PCoA to the postclinoid-tentorium (D5) was 3.612±1.15 mm (max, 6.14; min, 1.83). The length (D6) of the exposed proximal ICA after the extradural clinoididectomy was 2.17±1.04 mm on the lateral side and 2.16±0.89 mm on the medial side. The thickness of the Yasargil clip blade used during the clipping surgery was 1.35 mm measured with a digital precision ruler. Conclusion : The proximal length obtained by performing an external anterior clinoidectomy is about 2 mm, sufficient for proximal control during PCoA aneurysm surgery, considering the thickness of the aneurysm clips. In a subarachnoid hemorrhage, performing an extradural anterior clinoidectomy could prevent a devastating situation during PCoA aneurysm clipping.