Microsurgical Resection of Trigeminal Schwannomas: 3-Dimensional Operative Video.

Trigeminal schwannomas are benign lesions arising from the Schwann cells of the trigeminal nerve. This is an unusual tumor that accounts for less than 0.4% of intracranial pathologies, even though they are the second most frequent schwannoma after the vestibular schwannoma. The tumor spreads along the natural course of the V nerve at its cisternal portion, along the ganglion inside Meckel's cave or through its peripheral division. Even though the tumor can reach great size and become multicompartmental. We present a 51-yr-old woman, with an history of 3 mo of incapacitating facial pain, that was found on examination to be on the territory of the third division of the trigeminal nerve on the right side. The MRI depicted a large homogeneous enhancing lesion at the base of the right middle fossa with extension through the petrous apex to the most superior and medial part of the posterior fossa. The patient was operated by the senior author, through a middle fossa approach, dissecting between the two layers of the middle fossa dura (the apparent inner and the true outer layer of the cavernous sinus), the so called middle fossa "peeling". We achieved total resection of the tumor, but the patient presented after surgery with facial nerve paresis. This is thought to be related to geniculate ganglion manipulation, as it was unprotect by bone at the middle fossa and the patient maintained lacrimal function (post-geniculate alteration). It resolved completely after 6 mo. The patient consented to publication of her images.

Anterior Transpetrosal Approach and Microsurgical Resection of a Petrous Tentorial Meningioma: 3-Dimensional Operative Video.

Tentorial meningiomas are challenging tumors because of its complex relationship with vital neurovascular structures. We present the case of a 41-yr-old female with a history of right-sided facial numbness associated with pain around the ear. Magnetic resonance imaging demonstrated a lesion in the right tentorium edge closely related with the porus trigeminus, suggestive of a meningioma. Because of worsening of symptoms the patient underwent surgery for tumor removal. A standard temporo-zygomatic craniotomy was performed, followed by an extradural peeling of the middle fossa; the petrous apex was drilled allowing access to the posterior fossa dura. Dural opening was carried connecting the temporal and posterior fossa, and the tentorium was then cut to the incisura. The tumor was identified and completely removed reaching Simpson grade I resection. Postoperatively, the patient presented a right dry eye in the first days that fully improved, and also a right-sided facial paralysis (House-Brackmann grade IV) and diplopia, both recovered completely after 4 mo. We believe that facial paralysis was the result of an undesired traction of the geniculate ganglion, or upon the nerve itself. To avoid such complication, dissection over the GSPN must be carried parallel to that nerve. Facial numbness and pain improved with no neurological other deficits. Tentorial meningiomas are complex deep-seated lesions that can be successfully approached through an anterior transpetrosal route in selected cases. Informed consent was obtained from the patient for publication of this operative video. Anatomical images were a courtesy of the Rhoton Collection, American Association of Neurological Surgeons/Neurosurgical Research and Education Foundation.

Microsurgical Resection of Glomus Jugulare Tumors With Facial Nerve Reconstruction: 3-Dimensional Operative Video.

Paragangliomas are tumors originating from the paraganglionic system (autonomic nervous system), mostly found at the region around the jugular bulb, for which reason they are also termed glomus jugulare tumors (GJT). Although these lesions appear to be histologically benign, clinically they present with great morbidity, especially due to invasion of nearby structures such as the lower cranial nerves. These are challenging tumors, as they need complex approaches and great knowledge of the skull base. We present the case of a 31-year-old woman, operated by the senior author, with a 1-year history of tinnitus, vertigo, and progressive hearing loss, that evolved with facial nerve palsy (House-Brackmann IV) 2 months before surgery. Magnetic resonance imaging and computed tomography scans demonstrated a typical lesion with intense flow voids at the jugular foramen region with invasion of the petrous and tympanic bone, carotid canal, and middle ear, and extending to the infratemporal fossa (type C2 of Fisch's classification for GJT). During the procedure the mastoid part of the facial nerve was identified involved by tumor and needed to be resected. We also describe the technique for nerve reconstruction, using an interposition graft from the great auricular nerve, harvested at the beginning of the surgery. We achieved total tumor resection with a remarkable postoperative course. The patient also presented with facial function after 6 months. The patient consented with publication of her images.

Microsurgical Resection of Cerebellopontine Angle Meningioma.

Meningiomas of the cerebellopontine angle (CPA) are the second most frequent lesions related to this region (around 10-15%), 1 being the vestibular schwannomas the first (around 85%). This lesions arise from the dura of the petrosal surface of the temporal bone, lateral to the trigeminal nerve ( Fig. 1 ). Variable attachment sites and directions of growth make different clinical presentations and operative challenges. This pathologies can be classified accordingly to they're extension related to the internal acoustic meatus in: postmeatal, premeatal, and large meningiomas with pre- and postmeatal extension ( Fig. 2 ). We present an operative video performed by the senior author (L.A.B.B.). A 64-year-old woman with 3 months of complaint of left facial pain on the V2 territory of the trigeminal nerve and diplopia secondary to VI nerve paresis. Magnetic resonance imaging (MRI) scans demonstrated a large homogeneous enhancing lesion at the left CPA, extending pre- and postmeatal and from the tentorium cerebeli to the jugular foramen region, highly suggestive of CPA meningioma. Surgery was offered to the patient as a first option. In our point of view, neurophysiological monitoring with somatosensory and motor evoked potentials is mandatory while dealing with such large tumors around the CPA. The surgery was performed after a standard retrosigmoid craniotomy, with careful dissection and debulking while devascularizing the tumor from its petrosal attachment. Near-total resection was achieved and the patient had a remarkable postoperative outcome with improvement of the diplopia and facial pain with preservation of VII and VIII nerves function. The pathology demonstrated a grade 1 meningioma. The link to the video can be found at: https://youtu.be/UVVyEhq8Fu0 .

Microsurgical resection of foramen magnum meningioma through a transcondylar approach: three-dimensional operative video.

Foramen magnum (FM) meningiomas are challenging lesions. We present the case of a 38-year-old female with neck pain, dysphonia, and slight twelfth nerve palsy. Imaging workup was highly suggestive of an FM meningioma, and microsurgical resection with the aid of intraoperative neurophysiological monitoring was indicated. A transcondylar approach was employed, the vertebral artery was mobilized, and the tumor was completely removed. Postoperative MRI demonstrated complete resection. There were no signs of cervical instability. The patient presented with improvement of her symptoms and no new neurological deficit on follow-up. FM meningiomas can be successfully resected using a transcondylar approach, since it increases the exposure of the ventral FM, allowing the surgeon to work parallel to the skull base and flush with the tumor's attachment. Informed consent was obtained from the patient for publication of this operative video. The video can be found here: https://youtu.be/itfUOB-6zM0.

Microsurgical Resection of Lateral Tuberculum Sellae Meningioma: Operative Video.

Tuberculum Sellae Meningiomas (TSMs) are lesions dramatically related to the optic apparatus once the principal clinical complain remains on visual alterations. This is the main picture on decision making to evaluate the best time, risk-benefit, and surgical approaches to the patient treatment. In this video, we present a 65 years old female with 30 days complaint of unilateral (right) complete blindness and complete impaired right eye field test. On physical examination, there were normal pupillary function to light tests. The scans demonstrated the presence of a TSM mostly related to the right optic nerve and encasing it altogether with the right internal carotid artery. Promptly, surgery was addressed using a modified one piece cranio-orbital-zygomatic approach with extra-dural anterior clinoidectomy, as this is the procedure of choice of the senior author (LB), with easy access to decompression of the optic canal and nerve. As demonstrated on the video, the optic nerve was encased by the tumor and pushed upwards against the falciform ligament. Complete resection and decompression was established with step by step dissection, starting unroofing the optic canal, opening the ligament and finally with carefully tumor debulking. Pathology demonstrated a grade one meningioma. The patient improved remarkably her visual acuity and visual field tests on the postoperative period, emphasizing the importance of early treatment for nerve function outcome. The link to the video can be found at: https://youtu.be/pALZqDUkltQ .

Combined Presigmoid and Retrosigmoid Approach to Petroclival Meningiomas.

Introduction The management of petroclival meningiomas is among the most intimidating in neurosurgery, due to its difficult accessibility and close relationship with vital structures; therefore, an appropriate exposure is mandatory. We present a surgical video demonstrating a presigmoid transtentorial approach, associated with the opening of the retrosigmoid dura to a petroclival meningioma, performed by the senior surgeon (L.A.B.B.), along with its indications and pitfalls. Approach Decision The patient's clinical history is summed to the tumor's radiological features as its extension, vascularization, and venous drainage, when selecting the appropriate approach. The presigmoid transtentorial approach offers a wide exposure of the petroclival area along with the tumor's attachment. Its association with the retrosigmoid route allows the surgeon to freely work through multiple paths, and parallel to the skull base, reducing the traction in the temporal lobe. Clinical Case This is a 39-year-old female presenting with trigeminal neuralgia. Imaging depicted a petroclival meningioma, extending from the posterior aspect of the cavernous sinus to the cerebellopontine angle, extending inferiorly to the jugular bulb. A Simpson II resection was achieved through a combined presigmoid and retrosigmoid approach, and the patient was discharged with no complications or new deficits. Conclusion Petroclival meningiomas are a formidable and surgically treatable disease. The appropriate approach is design to each patient and should not be the limiting factor for total tumor removal, which is truly given by the absence of a dissection plane between the tumor and the brainstem, nerves and vascular structures of the skull base. The link to the video can be found at: https://youtu.be/MFjqZvElBSo .