Microsurgical resection of a large petroclival meningioma via translabyrinthine approach combined with middle fossa craniotomy.

Petroclival meningiomas arise from the upper two-thirds of the clivus at the petroclival junction and are reached via various approaches. As petroclival meningiomas expand, they displace the brainstem and basilar artery toward the contralateral side. Because of their proximity to critical structures and deep skull base location, surgical treatment is challenging. Although several approaches have been introduced, their rationales vary. Herein, the authors demonstrate microsurgical resection of a large petroclival meningioma via a translabyrinthine approach combined with middle fossa craniotomy. For each approach, the pros and cons should be carefully evaluated based on the patient's presentation and lesion characteristics. The video can be found here: https://stream.cadmore.media/r10.3171/2022.1.FOCVID21253.

How I do it: management of M2 tear injury caused by drilling during intradural anterior clinoidectomy for microsurgical clipping of intracranial aneurysms.

BACKGROUND: High-speed drilling is associated with potential injury to neurovascular structures, particularly during intradural drilling of the anterior clinoid process. METHOD: During an anterior clinoidectomy, a cotton patty and middle cerebral artery branches became inadvertently wrapped around the bit, causing a tear on the inferior M2 trunk. Following temporary clipping of the internal carotid artery, the tear was identified. Temporary clips were placed proximally and distally. The tear was then repaired with interrupted microsutures. CONCLUSION: Extreme care should be exercised during clinoidectomy. Should small vascular injury occur, direct microsuturing can be a good alternative to sacrificing or implantation anastomosis repair.

A Rare Complication of Endovascular Embolization: Extruded Onyx on Trigeminal Nerve.

Objectives To demonstrate a rare complication of endovascular tumor embolization with onyx. Design Operative video. Setting Department of neurological surgery in a university hospital. Participants A 39-year-old male who was diagnosed with a right sided hemangioblastoma. Main Outcome Measures Surgical resection of the tumor, preservation of the cranial nerves and extruded embolization material on trigeminal nerve. Results The tumor was embolized with onyx the day before surgery. Patient woke up with no sensation in the right side of his face. Diffusion magnetic resonance imaging (MRI) showed a small restricted diffusion area within the right superior cerebellar vermis. Microsurgical resection of the tumor was uneventful and complete resection was achieved (Fig. 1). After the resection was completed, the trigeminal nerve was identified. Some of the capillaries overlying the nerve as well as the cerebellum and brain stem had extruded onyx-embolic material (Fig. 2). Some of the onyx over the cerebellum was removed; however, the ones on the trigeminal nerve and brain stem were not removed due to the risk of injury to the nerve. Postoperative MRI confirmed total resection. Patient made excellent recovery except he continued to have no sensation in the right side of his face. Conclusion Preoperative embolization is an important adjunct to resection of large hemangioblastomas in selected cases because it may facilitate circumferential dissection and debulking of the tumor. Although extrusion of the embolization material is relatively common, immediate extrusion of onyx and its transfixion on a cranial nerve has not been reported before. Judicial selection of preoperative embolization is required in hemangioblastomas. The link to the Video can be found at: https://youtu.be/s0DjD26Xkas .

Gross Total Resection of Chordoid Glioma of the Third Ventricle via Anterior Interhemispheric Transcallosal Transforaminal Approach at Two Stages.

Suprasellar tumors in particular tumors located in the retrochiasmatic area and anterior third ventricle are challenging cases in terms of optimal surgical exposure. Several approaches have been described including transsylvian, translamina terminalis, endoscopic endonasal, and anterior interhemispheric. Each approach has advantages and disadvantages. In this video, we present a case of retrochiasmatic anterior third ventricular tumor that was operated via anterior interhemispheric transcallosal transforaminal approach. The patient is a 42-year-old female who presented with sudden onset of severe headache and depressed level of consciousness. Computed tomography (CT) scan of the head showed a hemorrhage in the third ventricle and suprasellar cisterns. CT angiogram and magnetic resonance imaging (MRI) confirmed diagnosis of hemorrhagic mass lesion in the third ventricle. Upon further questioning of her family, we found out that she was having excessive urination and short-term memory problems for last 2 weeks. First, ventriculostomy was placed for obstructive hydrocephalus. She then underwent surgical resection via anterior interhemispheric transcallosal transforaminal approach. Foramen of Monro was enlarged by performing transchoroidal dissection. Using transforaminal route, tumor was resected. Due to the narrow surgical corridor and high vascularity of the tumor, decision was made to come back at a second stage. Using same surgical approach, in the second stage, gross total resection was performed. Postoperative MRI confirmed gross total resection. Histopathology was chordoid glioma of the third ventricle. She made excellent recovery with persistent diabetes insipidus. Currently, she is completing radiation therapy. In this video, we demonstrate techniques and pitfalls of anterior interhemispheric transcallosal approach to anterior third ventricular tumor. The link to the video can be found at: https://youtu.be/CI5c6Zup8sY .

Microsurgical Resection of Tuberculum Sellae Meningioma via Pterional Craniotomy with Extradural Anterior Clinoidectomy and Optic Unroofing.

Microsurgical treatment of suprasellar tumors, in particular tuberculum sellae meningiomas, poses significant challenge. These tumors are surrounded by vital neurovascular structures, such as optic apparatus, pituitary stalk, internal carotid artery and its branches, and anterior cerebral arteries. In large and complex cases, early identification and decompression of these structures may facilitate safer dissection and resection. Therefore, extradural anterior clinoidectomy with optic unroofing facilitates the internal carotid artery exposure and optic nerve decompression. In this video, we describe a 37-year-old female patient who presented with new onset of severe headaches. On visual examination, she was found to have bitemporal visual defects. MRI scan of the head showed a large, approximately 3 cm suprasellar tumor consistent with tuberculum sellae meningioma. She underwent surgical resection via pterional craniotomy with extradural anterior clinoidectomy and optic unroofing. Microsurgical gross total resection was achieved and histopathology was WHO grade II meningioma. She had an uneventful postoperative course and visual field examination improved significantly. In this video, surgical technique in performing extradural anterior clinoidectomy and optic unroofing and steps of microsurgical resection are demonstrated. The link to the video can be found at: https://youtu.be/oPZ8NTyvxJc .

Ruptured Distal Accessory Anterior Cerebral Artery Aneurysm: A case report and literature review.

Aneurysms of the distal anterior cerebral artery (dACA) are rare, consisting only 2-6% of all intracranial aneurysms. dACA aneurysms are often associated with anomalies such as azygous, bihemispheric and triplication of ACA. Among these anomalies accessory anterior cerebral artery (accACA) is an anatomical variant found in 3.3% to 15% of the population. Here we report a case of a 60-year-old female who presented with a Hunt and Hess grade II, Fisher grade III subarachnoid hemorrhage secondary to a ruptured saccular aneurysm originating from the pericallosal-callosomarginal artery bifurcation at the A3 segment of the accessory ACA and underwent an uncomplicated microsurgical clipping.

Intracranial blastomycosis presenting as an enhancing cerebellopontine mass.

Isolated Blastomyces dermatitidis infection of the central nervous system is an uncommonly encountered entity. If left untreated it can be fatal; thus accurate diagnosis in a timely manner is critical. A 37-year-old white male presented with a severe headache. An MRI scan revealed a right-sided enhancing cerebellopontine angle mass with extension into the internal acoustic canal and diffuse basilar enhancement. After thorough assessment of the patient, an open surgical biopsy of the lesion was performed for pathological evaluation. The biopsy demonstrated broad-based budding yeasts. The cerebrospinal fluid antigen enzyme immunoassay (EIA) (MVista®) for Blastomyces dermatitidis was also positive with a level of 4.28 EIA units.

Does the sphenoid angle effect the operation strategy? Anatomical and radiological investigation.

AIM: The aim of our study is to suggest the sphenoid wing-lesser wing angulation (SWA) importance during surgeries directed to this region. MATERIAL AND METHODS: SWA on 40 skulls were measured bilaterally (n=80). The depth of the middle cranial fossa (DMCF) at the level of the SWA was determined. The same measurements were done on 40 randomly selected computerized tomography (CT) scans bilaterally (n=80). RESULTS: The specimens were classified into 3 groups according the degree of SWA; Group-A, SWA was more than 130° (27%), Group-B, SWA was 110-130° (43%) and Group-C, SWA was less than 110° (28%). MCF was measured (mean) as 10.1 mm in Group-A, 6.4 mm in Group-B and 4.6 mm in Group-C. MCF was increasing with the increase in SWA. CT scans were classified into same procedure. Group-A was 26%, Group-B was 42% and Group-C was 31% fitting in the relevant groups. The superior orbital fissure (SOF) was evaluated according to the Sharma's classification. CONCLUSION: We suggest that by the preoperative evaluation of CT scans measurements the SWA, it is possible to estimate the MCF and the type of SOF. This knowledge may be important for all surgeries requiring removal of the sphenoid wing and these region pathologies.

Anatomy of Meckel's cave and the trigeminal ganglion: anatomical landmarks for a safer approach to them.

AIM: Surgical approaches to Meckel's cave (MC) are often technically difficult and sometimes associated with postoperative morbidity. The relationship of surgical landmarks to relevant anatomy is important. Therefore, we attempted to delineate quantitatively their anatomy and the relationships between MC and surrounding structures. MATERIAL AND METHODS: With the aid of a surgical microscope, MC and its contents were studied in 15 formalin-fixed cadaver head specimens. Measurements were made and their relationships were observed. RESULTS: The distance from the zygomatic arch and the lateral end of the petrous ridge to MC was 26.5 and 34.4 mm, respectively. The distance from the arcuate eminence, the facial nerve hiatus, and the foramen spinosum to MC was 16.6, 12.8 and 7.46 mm respectively. The TG lay 5.81 mm posterior to the foramen ovale. The distance from the abducens, trochlear and oculomotor nerves to the trigeminal ganglion was 1.87, 5.53 and 6.57 mm respectively. The distance from the posterior and the anterior walls of the sigmoid sinus to the trigeminal porus was 43.6 and 33.1 mm respectively. The trigeminal porus was on average 7.19 mm from the anterior wall of the internal acoustic meatus. CONCLUSION: The anatomical landmarks as presented herein regarding MC may be used for a safer skull base approach to the region.