Introduction: Central nervous system solitary fibrous tumors (CNS-SFTs), previously classified as hemangiopericytomas, are rare and highly vascular mesenchymal neoplasms characterized by an aggressive biological behavior, high recurrence rates, and propensity for venous sinus invasion. Gross-total en bloc resection remains the cornerstone of treatment whenever technically feasible. We present the microsurgical management of a recurrent CNS solitary fibrous tumor invading the transverse sinus. Case Report: A 30-year-old man previously underwent microsurgical resection of a central nervous system solitary fibrous tumor two years earlier. He presented with recurrent headaches associated with visual photopsias. Magnetic resonance imaging demonstrated tumor recurrence centered at the left occipital region with extensive invasion of the left transverse sinus. Preoperative digital subtraction angiography confirmed complete occlusion of the left transverse sinus, allowing safe planning for sinus sacrifice during tumor resection. Microsurgical treatment was performed through a combined left occipital supratentorial and infratentorial craniotomy. To maximize exposure of the transverse-sigmoid junction, a retrosigmoid mastoidectomy was performed, permitting complete skeletonization of the transverse and sigmoid sinuses and facilitating vascular control. Following extradural exposure, the proximal transverse sinus was ligated near the torcular Herophili under direct microscopic visualization after confirming intraluminal tumor extension. Distal ligation was subsequently completed, and the tumor was removed en bloc together with the invaded segment of the transverse sinus, achieving gross-total resection while preserving the surrounding neurovascular structures. Results: The immediate postoperative neurological examination demonstrated no new neurological deficits. During the postoperative period, the patient developed communicating hydrocephalus, cerebrospinal fluid leakage, and bacterial meningitis. These complications were successfully managed with direct surgical repair of the cerebrospinal fluid fistula, implantation of a programmable ventriculoperitoneal shunt, and targeted intravenous antibiotic therapy. The patient recovered without permanent neurological sequelae. Postoperative magnetic resonance imaging confirmed gross-total tumor resection, and follow-up imaging demonstrated no evidence of residual disease. Conclusion: Complete microsurgical resection remains the treatment of choice for recurrent CNS solitary fibrous tumors involving the dural venous sinuses. When preoperative angiography confirms complete venous sinus occlusion, en bloc resection of the involved transverse sinus can be safely performed. A combined occipital supratentorial-infratentorial approach with adjunctive mastoidectomy provides excellent exposure of the transverse-sigmoid junction, facilitating vascular control and radical tumor removal while minimizing neurological morbidity.
Introduction: The retrolabyrinthine approach is a valuable hearing-preservation technique for selected patients with small vestibular schwannomas and serviceable hearing. By preserving the otic capsule while providing a direct surgical corridor to the cerebellopontine angle and posterior aspect of the internal auditory canal, this approach may allow complete tumor removal with limited manipulation of the cerebellum and auditory structures. Careful patient selection, precise temporal bone drilling, meticulous microsurgical dissection, and continuous intraoperative neurophysiological monitoring are essential for optimizing functional outcomes. For the retrolabyrinthine approach, the retrolabyrinthine window—defined as the surgical corridor posterior to the labyrinth and anterior to the sigmoid sinus—should be made as wide as possible to maximize surgical exposure and working space Case Report: A 43-year-old man presented with a Koos grade II vestibular schwannoma and preserved serviceable hearing. Microsurgical gross-total resection was performed through a retrolabyrinthine approach with the patient in the supine position. Following mastoidectomy, the anatomical limits of the retrolabyrinthine corridor were carefully defined, preserving the semicircular canals and avoiding violation of the otic capsule. Adequate bone removal created a sufficiently wide surgical window to expose the posterior internal auditory canal and cerebellopontine angle while maintaining the integrity of the labyrinth. Continuous intraoperative neurophysiological monitoring was used throughout the procedure, including auditory brainstem responses (ABRs), facial motor evoked potentials (MEPs), and direct facial nerve stimulation. Progressive tumor debulking and meticulous microsurgical dissection were performed under high magnification, with particular attention to preservation of the arachnoid planes, cochlear nerve, facial nerve, and vascular supply to the auditory structures. The posterior internal auditory canal was adequately exposed without drilling the otic capsule, maximizing the possibility of hearing preservation. Gross-total tumor removal was achieved with anatomical and functional preservation of both the cochlear and facial nerves. Results: Postoperatively, the patient maintained serviceable hearing and demonstrated normal facial nerve function, corresponding to House-Brackmann grade I, without new neurological deficits. Conclusion: The retrolabyrinthine approach is an effective hearing-preservation option for carefully selected Koos grade II vestibular schwannomas. Creation of an adequately wide retrolabyrinthine corridor, preservation of the otic capsule, meticulous microsurgical dissection, and multimodal neurophysiological monitoring are fundamental for achieving gross-total resection while preserving cochlear and facial nerve function. This technique provides a good balance between tumor control and functional preservation in appropriately selected patients.
Introduction: Paraclinoid internal carotid artery (ICA) aneurysms involving the distal dural ring are among the most technically demanding lesions in cerebrovascular neurosurgery because of their close relationship with the optic nerve, anterior clinoid process, and carotid branches. Safe microsurgical treatment requires reliable proximal vascular control, adequate exposure of the paraclinoid ICA, precise identification of the aneurysm neck, and meticulous clip reconstruction while preserving adjacent neurovascular structures. This surgical video demonstrates key technical steps for clipping these complex aneurysms. Case Report: A 63-year-old man was incidentally diagnosed with a right paraclinoid ICA aneurysm involving the distal dural ring. A standard right pterional craniotomy was performed. Because of the aneurysm morphology and its close relationship with the distal dural ring, proximal vascular control was first obtained through cervical exposure of the right internal carotid artery. Temporary cervical ICA occlusion was applied during critical stages of dissection to reduce aneurysm wall tension and facilitate safe manipulation of the aneurysm neck. After wide opening of the sylvian fissure, the paraclinoid ICA was exposed. An intradural anterior clinoidectomy was performed using a high-speed drill, allowing removal of the anterior clinoid process and progressive exposure of the distal dural ring. This maneuver increased working space and provided direct visualization of the proximal aneurysm neck. Careful circumferential microsurgical dissection was then performed to define the relationship between the aneurysm, ICA, optic apparatus, and surrounding structures. After complete identification of the aneurysm neck and adequate vascular control, definitive reconstruction was achieved using two permanent aneurysm clips. Clip placement was performed under direct microscopic visualization, with attention to maintaining parent artery patency and preserving adjacent branches. Intraoperative inspection confirmed complete aneurysm exclusion with preservation of the internal carotid artery and its major branches. Results: The patient had an uneventful postoperative course, without neurological deficits and was discharged home 72 hours after surgery. Conclusion: Microsurgical clipping remains an excellent treatment option for selected paraclinoid aneurysms involving the distal dural ring. Cervical proximal carotid control combined with intradural anterior clinoidectomy provides controlled exposure of the paraclinoid ICA and aneurysm neck, reduces tension during dissection, and facilitates precise clip reconstruction. This surgical video highlights the importance of anatomical knowledge, proximal control, careful clinoid drilling, circumferential neck dissection, and preservation of the parent artery for management of these challenging lesions.
Introduction: Endolymphatic sac tumors (ELSTs) are rare, locally aggressive papillary neoplasms arising from the endolymphatic sac and duct. Although histologically benign, they may behave aggressively due to progressive bone erosion and invasion of adjacent neurovascular structures. Patients commonly present with progressive hearing loss, tinnitus, vertigo, and vestibular dysfunction, significantly affecting quality of life. Complete microsurgical resection remains the treatment of choice for symptomatic tumors, providing excellent long-term control when total removal is achieved. We present the surgical management of an endolymphatic sac tumor through a transmastoid approach, emphasizing anatomical landmarks and microsurgical principles. Case Report: A 40-year-old man presented with progressive left-sided pulsatile tinnitus, hearing loss, episodic vertigo, and aural fullness, causing significant functional impairment. Computed tomography revealed irregular erosive destruction of the retrolabyrinthine temporal bone, a characteristic finding of ELST. Magnetic resonance imaging demonstrated an intensely enhancing lesion centered on the left endolymphatic sac, located along the posterior surface of the petrous bone and adjacent to the posterior semicircular canal and sigmoid sinus. Microsurgical resection was performed through a transmastoid approach. After complete mastoidectomy, the sigmoid sinus, posterior semicircular canal, and Trautmann’s triangle were widely exposed, providing access to the posterior petrous region. Careful drilling and anatomical identification of surrounding structures allowed controlled tumor exposure while preserving the labyrinth and neurovascular anatomy. The posterior fossa dura within Trautmann’s triangle was opened, enabling direct visualization and complete microsurgical resection under high magnification. Tumor dissection was performed with meticulous attention to its relationship with the sigmoid sinus, posterior semicircular canal, and facial nerve. Continuous unimodal intraoperative facial nerve monitoring was used throughout the procedure, allowing functional assessment and preservation of facial nerve integrity. Gross-total tumor removal was achieved without injury to surrounding neurovascular structures. The operative field was carefully inspected to confirm complete resection and adequate hemostasis. Results: The postoperative course was uneventful, with complete resolution of pulsatile tinnitus and preservation of facial nerve function. The patient remained neurologically intact during long-term follow-up. After 12 years of clinical and radiological surveillance, there was no evidence of tumor recurrence, and the patient remained asymptomatic with preserved neurological function. Conclusion: The transmastoid approach provides a direct and effective surgical corridor for selected endolymphatic sac tumors. Wide exposure of Trautmann’s triangle allows safe access to the posterior petrous region, facilitating complete microsurgical resection while minimizing morbidity. This case demonstrates that tailored skull base surgery can provide durable tumor control and excellent long-term functional outcomes when complete removal is anatomically feasible.
Introduction: Microsurgical resection through the retrosigmoid approach remains a standard treatment option for intracanalicular vestibular schwannomas, particularly in young patients with serviceable hearing. In selected cases, surgery provides immediate tumor removal and long-term tumor control while offering the possibility of preserving hearing and facial nerve function. Meticulous microsurgical technique and continuous intraoperative neurophysiological monitoring are essential to optimize functional outcomes. Case Report: An 18-year-old woman presented with a right-sided Koos grade I intracanalicular vestibular schwannoma and preserved serviceable hearing. Gross-total tumor resection was performed through a retrosigmoid approach with the patient in the park-bench position. After dural opening, cerebrospinal fluid was released to obtain cerebellar relaxation and minimize the need for cerebellar retraction. The internal auditory canal was widely drilled to expose the intracanalicular tumor. Microsurgical dissection was performed under high magnification with continuous neurophysiological monitoring, including auditory brainstem responses (ABRs), facial motor evoked potentials (MEPs), and direct facial nerve stimulation. Particular attention was given to preservation of the arachnoid planes, cochlear nerve, facial nerve, and vascular supply to the auditory structures. Careful tumor mobilization and progressive dissection allowed gross-total removal with anatomical and functional preservation of both the cochlear and facial nerves. Postoperatively, the patient maintained serviceable hearing and normal facial nerve function, corresponding to House–Brackmann grade I, without new neurological deficits. Results: Long-term magnetic resonance imaging follow-up demonstrated no evidence of residual or recurrent tumor. The patient continues to maintain serviceable hearing and normal facial nerve function, confirming a durable favorable outcome. Conclusion: Microsurgical resection through the retrosigmoid approach is an excellent definitive treatment option for selected young patients with small intracanalicular vestibular schwannomas and preserved hearing. Adequate exposure of the internal auditory canal, meticulous microsurgical dissection, preservation of neural and vascular structures, and multimodal neurophysiological monitoring can allow gross-total tumor removal while maintaining hearing and facial nerve function. In appropriately selected patients, this strategy provides durable tumor control and long-term functional preservation without leaving a residual lesion requiring continued surveillance.
