Cavernous venous malformations in and around the central nervous system. Part 1: Dural and extradural.

Cavernous-type malformations are venous lesions that occur in multiple locations throughout the body, and when present in the CNS, they have canonically been referred to as cavernomas, cavernous angiomas, and cerebral cavernous malformations. Herein all these lesions are referred to as "cavernous venous malformations" (CavVMs), which is congruent with the current International Society for the Study of Vascular Anomalies classification system. Even though histologically similar, depending on their location relative to the dura mater, these malformations can have different features. In Part 1 of this review, the authors discuss and review pertinent clinical knowledge with regard to CavVMs as influenced by anatomical location, starting with the dural and extradural malformations. They particularly emphasize dural CavVMs (including those in the cavernous sinus), orbital CavVMs, and spinal CavVMs. The genetic and histopathological features of CavVMs in these locations are reviewed, and commonalities in their presumed mechanisms of pathogenesis support the authors' conceptualization of a spectrum of a single disease entity. Illustrative cases for each subtype are presented, and the pathophysiological and genetic features linking dural and extradural to intradural CavVMs are examined. A new classification is proposed to segregate CavVMs based on the location from which they arise, which guides their natural history and treatment.

Cavernous venous malformations in and around the central nervous system. Part 2: Intradural.

Cavernous venous malformations (CavVMs) account for a spectrum of lesions with a shared pathogenesis. Their anatomical location dictates their clinical features and surgical treatment. Extradural and dura-based CavVMs were discussed in Part 1 of this review. In this part, intradural CavVMs are discussed, encompassing malformations growing within the intradural space without direct dural involvement. In addition to classic intra-axial CavVMs, cranial nerve CavVMs, intraventricular CavVMs, and intradural extramedullary spinal CavVMs are discussed in this group, given the similar natural history and specific management challenges. Herein the authors focus on critical clinical aspects of and surgical management of these malformations based on their location and discuss optimal surgical approaches at each of these anatomical locations with illustrative cases. The commonalities of the natural history and surgical management that are dictated by anatomical considerations lend to a new location-based taxonomy for classification of CavVMs.

Positioning Transclival Tumor-Treating Fields for the Treatment of Diffuse Intrinsic Pontine Gliomas.

Diffuse intrinsic pontine glioma (DIPG) carries an extremely poor prognosis, with 2-year survival rates of <10% despite the maximal radiation therapy. DIPG cells have previously been shown to be sensitive to low-intensity electric fields in vitro. Accordingly, we sought to determine if the endoscopic endonasal (EE) implantation of an electrode array in the clivus would be feasible for the application of tumor-treating fields (TTF) in DIPG. Anatomic constraints are the main limitation in pediatric EE approaches. In our Boston Children's Hospital's DIPG cohort, we measured the average intercarotid distance (1.68 ± 0.36 cm), clival width (1.62 ± 0.19 cm), and clival length from the base of the sella (1.43 ± 0.69 cm). Using a linear regression model, we found that only clival length and sphenoid pneumatization were significantly associated with age (R2 = 0.568, p = 0.005 *; R2 = 0.605, p = 0.0002 *). Critically, neither of these parameters represent limitations to the implantation of a device within the dimensions of those currently available. Our findings confirm that the anatomy present within this age group is amenable to the placement of a 2 × 1 cm electrode array in 94% of patients examined. Our work serves to demonstrate the feasibility of implantable transclival devices for the provision of TTFs as a novel adjunctive therapy for DIPG.

Falcotentorial Meningioma Resection Through the Supracerebellar Infratentorial Approach: 2-Dimensional Operative Video.

Meningiomas are a common pineal region tumor in adults.1 They frequently reach large size with pending serious neurological consequences.1 Although they are more common in women, their presence in men might raise concerns about a higher-grade meningioma. Accordingly, their treatment starts with surgical resection. Their origin is the falcotentorial junction involving the midbrain tectum and the vital deep venous system. The torcular, transverse sinuses, cerebellar veins, straight sinus, internal occipital veins, basal veins, and internal cerebral veins are encountered requiring a cautious fine intra-arachnoidal dissection under high magnification.2 Multiple surgical approaches are described for pineal area tumors with the advantages and disadvantages of each guiding the selection of the approach.3 We believe that the main deciding factor is the relationship of the vein of Galen and its tributaries to the tumor, simply choosing the route that encounters the tumor first and the vein last. We demonstrate the surgical nuances of removing a pineal area meningioma that displaced the vein of Galen superiorly, prompting the resection through a lateral infratentorial supracerebellar approach. We currently prefer the 3/4 concord position because it provides a superb direct exposure over one cerebellar hemisphere, with the cerebellum relaxed downward while the bridging veins are not severely stretched with gravity.4 The sitting surgeon with resting arms in an ergonomic position is able to perform fine microsurgical dissection over extended time.5 The patient was a 57-year-old man with a large falcotentorial meningioma. The patient consented to the surgery and publication of his images.

Preservation of Cranial Nerves Function in Glomus Jugulare Surgery: 2-Dimensional Operative Video.

Owing to their invasive character, extreme vascularity, and critical location, glomus jugulare tumors present a formidable challenge. Techniques have been developed for safe and successful removal of even giant glomus paragangliomas.1-3 Preoperative evaluation including genetic, hormonal, and multiplicity workup4 has enhanced the safety of surgical management, as did modern preoperative embolization by eliminating excessive blood loss.5 Despite these advancements, surgical outcomes of glomus jugulare remain haunted by cranial nerve dysfunction such as facial nerve palsies and hearing loss, with lower cranial nerves dysfunction being the most morbid. These can be avoided by technical maneuvers to preserve the cranial nerves. The external ear canal is not closed to maintain conductive hearing. The facial nerve is not transpositioned and kept inside a bony protective canal. Cranial nerves IX, X, and XI are the most vulnerable because they pass through the jugular foramen ventral to the venous bulb wall. They are preserved by intrabulbar dissection that maintains a protective segment of the venous wall over the nerves. By mastering the anatomy of the upper neck, meticulous dissection is performed to preserve the course of IX, X, XI, and XII.6,7 Ligation of the jugular vein is delayed until the tumor is totally isolated to avoid diffuse bleeding.7 We present the case of a 60-yr-old woman with a glomus jugulare tumor with intradural, extradural, and cervical extension. The technical nuances of cranial nerves preservation are demonstrated. The patient consented to the procedure and publication of her images. Images at 2:12, 2:50, and 3:09 from Al-Mefty and Teixeira,6 with permission from JNSPG.

Multicentric Chordoma With Initial Resection by Bilateral Transcondylar Approach: 2-Dimensional Operative Video.

Chordoma is a rare skull base tumor with malignant behavior.1-3 It invades locally with high recurrences, metastasizes distally, and seeds after interventions.1-4 Chordoma exemplifies the malignant progression doctrine as it accumulated genetic mutations. The natural history of untreated disease is 2.4 yr on average survival.5 Best tumor control is achieved by radical resection, followed by high doses radiation. Multicentric chordoma is an ill-defined challenging entity extremely rare in the literature. However, chordoma is known for distal metastasis, particularly to the lungs, iatrogenic cerebrospinal fluid (CSF) dissemination with drop metastasis, or surgical implantation. A subset of patients present with synchronous or metachronous regional or distal neuraxial lesions associated with the initial chordoma. Patients presenting with multicentric bony axial lesions and no extra-axial metastases point toward the multicentric chordoma concept rather than local, hematogenous, or CSF spread.6-12 Biopsy of these multicentric lesions can show a spectrum of abnormalities ranging from benign notochordal tumor to chordomas confirming the multicentric hypothesis.9 We present a patient who underwent a bilateral transcondylar approach for giant craniovertebral junction chordoma and then treated with radiation and a second lesion at the C6 transverse foramen. Six years later, she presented with a chordoma at the petrous apex. The patient consented to surgery and to the publications of her image. The participants and any identifiable individuals consented to publication of his/her image. Image at 1:39 reprinted with permission from Al-Mefty O, Operative Atlas of Meningiomas. Vol 1, © LWW, 1998.

Standard clinical approaches and emerging modalities for glioblastoma imaging.

Glioblastoma (GBM) is the most common primary adult intracranial malignancy and carries a dismal prognosis despite an aggressive multimodal treatment regimen that consists of surgical resection, radiation, and adjuvant chemotherapy. Radiographic evaluation, largely informed by magnetic resonance imaging (MRI), is a critical component of initial diagnosis, surgical planning, and post-treatment monitoring. However, conventional MRI does not provide information regarding tumor microvasculature, necrosis, or neoangiogenesis. In addition, traditional MRI imaging can be further confounded by treatment-related effects such as pseudoprogression, radiation necrosis, and/or pseudoresponse(s) that preclude clinicians from making fully informed decisions when structuring a therapeutic approach. A myriad of novel imaging modalities have been developed to address these deficits. Herein, we provide a clinically oriented review of standard techniques for imaging GBM and highlight emerging technologies utilized in disease characterization and therapeutic development.

Interposition Grafting of the Facial Nerve After Resection of a Large Facial Nerve Schwannoma: 2-Dimensional Operative Video.

Facial nerve schwannomas can develop at any portion of the facial nerve.1 When arising from the mastoid portion of the facial nerve, the tumor will progressively erode the mastoid, giving the schwannoma an aggressive radiological appearance.1,2 The facial nerve is frequently already paralyzed, or no fascicles can be saved during resection. In these cases, end-to-end interposition grafting is the best option for facial reanimation.1,3-5 The healthy proximal and distal facial nerves are prepared prior to grafting. The great auricular nerve is readily available near the surgical site and represents an excellent graft donor with minimal associated morbidity.4,6 We demonstrate this technique through a case of a 48-yr-old male who presented with a complete right-sided facial nerve palsy due to a large facial schwannoma that invaded the mastoid and extended to the hypoglossal canal, causing hypoglossal nerve paralysis, and petrous carotid canal. His 4-yr follow-up showed no recurrent tumor with restored facial nerve function palsy to a House-Brackman grade III, and full recovery of his hypoglossal nerve function. The patient consented to the surgery and the publication of his image.

Extirpation of Recurrent Petrous Apex Cholesterol Granuloma Through the Zygomatic Approach: 2-Dimensional Operative Video.

Petrous apex cholesterol granulomas are believed to result from blockage of the normal aeration of the petrous air cells, resulting in a repetitive cycle of mucosal engorgement, hemorrhage, and granuloma formation.1 The lesion usually progressively expands causing compressive symptoms. The thick granulomatous wall envelopes various ages of breakdown products, including a cholesterol-containing fluid, which is typically hyperintense on T1 and T2 weighted magnetic resonance imaging. Drainage procedures, regardless of the route (endoscopic, endonasal, or transtemporal), with or without stenting or marsupialization, will only temporarily drain this cholesterol-containing fluid, with consequently frequent recurrences.2-5 A total exoneration of the granuloma and obliteration of the cavity with vascularized tissue will assure a more durable outcome.1 The extradural zygomatic/middle fossa approach provides a short distance to the petrous apex and is purely extradural. By sectioning the zygoma, temporal lobe retraction is avoided.6 We present a case of a 29-yr-old male who presented in the year 2000 with progression of a left petrous apex cholesterol granuloma despite 2 previous drainage and stenting procedures. The patient consented for surgery and photo publication. Images in video at 2:41 © JNSPG, republished from Eisenberg et al1 with permission.

Transcondylar Odontoid Resection and Stabilization for Craniovertebral Degenerative Compression: 2-Dimensional Operative Video.

Non-neoplastic craniovertebral junction lesions are well known with various etiologies.1,2 They are frequently associated with craniovertebral junction instability. Many require only stabilization for their management.2 However, when significant irreducible anterior compression is present, surgical decompression becomes necessary.2-4 The traditional decompression route is direct anterior, such as the transoral, transmaxillary, or endoscopic endonasal approaches with a separate posterior stabilization.1,2 The transcondylar approach offers a wide and direct exposure to the anterolateral foramen magnum and atlantoaxial space, allowing extensive decompression, total resection of the odontoid, and associated pannus, even with large lateral extension, as well as fusion in the same surgical setting.5 The surgical manipulation is parallel to the dural sac in the sagittal plane, which could be safer than perpendicular dissection.5 Understanding the regional anatomy allows safe exposure and transposition of the vertebral artery with the surrounding alveolar and venous plexus (suboccipital cavernous sinus).5-7 We present this technique's details in a case of a 72-yr-old female who presented with progressively worsening bilateral upper extremity weakness and significant anterior compression due to irreducible odontoid degenerative changes. We demonstrate the steps necessary to achieve adequate exposure and decompression. The patient agreed to the surgical intervention. Images at 2:46, 3:00, and 3:25 reused from Al-Mefty et al,5 by permission from JNSPG. Images at 9:28 from Symonds et al,3 by permission of Oxford University Press. Image at 2:15, © Ossama Al-Mefty, used with permission.

Metachronous Skull Base Paraganglioma Surgical Management: 2-Dimensional Operative Video.

Paragangliomas (PGLs) are benign hypervascular tumors that can develop in head and neck at different locations, primarily in the carotid bifurcation, jugular bulb, tympanic plexus, and vagal ganglia.1 Different gene mutations have been linked to the familial inherited forms, which can represent approximately 30% of all PGLs.1,2 These are classified into 5 different clinical syndromes: PGL 1 to 5.1 These patients have increased risk for synchronous and metachronous lesions requiring an extensive work-up for hormone secretion and other associated neoplasms, as well as attentive follow-up for lifelong management.1,3 Surgical resection is the best treatment option as it can be curative when the resection is total.2-4 Preservation of the lower cranial nerve function is central to the management of head and neck PGLs, given the gravity of bilateral injuries.3 Irradiation therapy should be considered if the risk for bilateral lower cranial nerve injuries is high.5 Surgically, intrabulbar resection with preservation of the medial wall of the jugular bulb protects the lower cranial nerve function.3 Other technical finesses, including maintaining the facial nerve in its bony fallopian canal (facial bridge), avoiding carotid artery sacrifice, preservation of the ear canal, and preoperative embolization, contributed markedly to outcome improvement.2,3 We report a case of a 34-yr-old male with PGL 3 with a left glomus jugulare tumor that recurred and a right carotid body tumor. Patient consented to surgery and photography. Image at 3:44 republished from Al-Mefty and Teixeira,3 with permission from JSNPG.

Resection of a Medulla Oblongata Hemangioblastoma: 2-Dimensional Operative Video.

Hemangioblastomas are benign vascular tumors that can be sporadic or multiple, as part of Von Hippel-Lindau disease. They develop at any level of the central nervous system, with a predilection for the dorsal medulla among brainstem locations. Radical resection of the solid portion of the tumor is the best treatment option.1,2 The resection should be en bloc to avoid uncontrollable intraoperative hemorrhage hindering safe dissection. Preservation of the venous drainage during the progressive dissection of the tumor of the surrounding structures and interruption of numerous small arterial feeders is a tenet for safe surgical resection.3 Once the tumor is completely disconnected, the large draining veins can be coagulated, and the tumor removed. We demonstrate these technical principles in the surgery of a 30-yr-old female with an exophytic hemangioblastoma from the dorsal medulla obstructing the fourth ventricle outflow. We demonstrate the resection of this lesion through a suboccipital craniotomy in a sitting position.4 The patient consented to the surgery and publication of images. Image at 1:26 from Kadri and Al-Mefty,4 by permission from the Congress of Neurological Surgeons.

Giant Ossified Clival Chondrosarcoma Resection: 2-Dimensional Operative Video.

Chondrosarcomas are a spectrum of tumors with variable clinical behavior, histologically classified as grades I, II, and III.1 Maximal surgical resection with adjuvant radiation is the gold standard for grade III malignant tumors.2,3 Lower-grade skull base chondrosarcomas have a slow progressive local growth pattern with an overall benign profile.1,4 In these grade I and II tumors, radical resection can be sufficient in achieving long-term control of the disease without the need for adjuvant therapy, thus avoiding the long-term side effects of irradiation in relatively young patients.4,5 As a slow-growing tumor, skull base chondrosarcoma might reach a giant size with progressive neurological deficits prior to diagnosis. In these cases, to achieve maximal resection, skull base approaches tailored to the patient's anatomy are essential.4,6 Cranial approach is frequently needed due to the calcified nature of part of the tumor that is not amenable to resection through the endonasal approach. The endoscope is extremely helpful combined with the microscopic resection. We demonstrate these techniques through in the surgery of a 39-yr-old female who presented with progressive neurological deficits from a giant ossified chondrosarcoma and underwent a combined petrosal approach for the resection of her tumor. A postoperative small enhancement remained stable on the 4-yr follow-up exam. The pathology confirmed grade II chondrosarcoma, with the patient recovering from her neurological deficit except the third nerve. The patient consented to the surgery and publication of images. Image at 1:36 reprinted with permission from Al-Mefty O, Operative Atlas of Meningiomas. Vol 1, ©LWW, 1998.

Combined Microscopic-Endoscopic Transmastoid Resection of a Petrous Meningioma: 2-Dimensional Operative Video.

Petrous meningiomas are defined as tumors with a basal dural attachment on the posterior surface of the petrous bone.1 Their insertion can be anterior to the meatus (petrous apex meningiomas), or posterior to the meatus, with associated hyperostotic bony invasion either pre- or retro-meatal.2 These meningiomas are amenable to curative surgical removal and have better surgical outcomes than more medially located true petroclival meningiomas that originate medial to the fifth nerve.2-4 They, however, remain challenging because of their close relationship to critical neurovascular structures in the cerebellopontine angle.5 The posterior petrous meningiomas might reach a significant size with compression of the cerebellum, the brainstem, and involvement of the cranial nerves, and extend posteriorly to the transverse sigmoid sinus.2,6 Transmastoid approach with skeletonization and lateral reflection of the transverse sigmoid sinus provides a superb exposure without cerebellar retraction.6,7 The ease and complete resection of the tumor and invaded bone can be facilitated by combined microscopic-endoscopic techniques. We demonstrate these principles through the resection of a petrosal meningioma in a 56-yr-patient who presented with headaches, nystagmus, and mild cerebellar signs. The patient consented to the procedure. Image at 1:36 reprinted with permission from Al-Mefty O, Operative Atlas of Meningiomas. Vol 1, ©LWW, 1998.

The Resection of a Thalamic Pilocytic Astrocytoma Through the Transchoroidal Fissure, Transcallosal Approach: 2-Dimensional Operative Video.

Surgical resection is the primary treatment of pilocytic astrocytomas and total removal can be curative. However, these lesions occur in critical areas, such as the thalamus, being surrounded by critical life neurovascular structures, which imposes a surgical challenge.1-5 Exhaustive acquisition and meticulous interpretation of preoperative radiological exams; reliable surgical orientation based on profound microneurosurgical anatomic knowledge and judicious discernment of the neuroanatomic distortions on the surface and deep-seated structures inflicted by the neuropathological entity; embracing and comprehensive application of the vast scope of available intraoperative guidance imaging and neurophysiological monitoring; in alliance with the mastered carefully microsurgical technique supported by endoscopic visualization are the keystones to the pursed duet "cure with quality of life" in the treatment of these lesions. We present the case of a 17-yr-old young lady with a progressive motor deficit in her right hemibody for over 2 yr. Her radiological investigation demonstrated a left thalamic lesion displacing the projection fibers (corticospinal tract) within the internal capsule laterally. The patient consented to the surgical procedure. The surgical strategy, intraoperative findings, and microsurgical and endoscopic technique, as well as the postoperative radiological and clinical evaluation are presented. The patient gave her informed consent for the publication of the case.

Recurrent Chordoma Resection in the Advanced Multimodality Image Guided Operating Suite: 2-Dimensional Operative Video.

Recurrent skull base chordomas are challenging lesions. They already had maximum radiation, and in the absence of any effective medical treatment, surgical resection is the only treatment.1,2 Surgery on recurrent previously radiated chordomas, however, carries much higher risk and the likelihood of subtotal resection. Maximizing tumor resection allows longer tumor control.3-5 The Advanced Multimodality Image Guided Operating Suite developed at the Brigham and Women's Hospital, Harvard Medical School, with the support of the National Institutes of Health, provides an optimal environment to manage these tumors. It offers the capability to obtain and integrate multiple modalities during surgery, including magnetic resonance imaging (MRI), positron emission tomography-computed tomography (PET-CT), endoscopy, ultrasound, fluoroscopy, and the ability to perform emergent endovascular procedures.5-7 The patient is a 39-yr-old male, presenting after 19 yr follow-up of a surgical resection and proton beam treatment for a skull base chordoma. He developed progressive ophthalmoplegia due to recurrence of his chordoma at the right petrous apex and cavernous sinus. Preoperative angiography demonstrated narrowing of the petrous segment of the right carotid artery suspect of radiation-induced angiopathy. The presence of radiation-induced angiopathy increases the risk of intraoperative carotid rupture, and the availability of endovascular intervention in the operative suite added favorable preparedness to deal with such complications if they happen. Given the clinical and radiological progression, surgical intervention was carried out through the prior zygomatic approach with the goal of performing maximum resection.8 The patient had an uneventful postoperative course and remained stable until he had a second recurrence 4 yr later. The patient consented to the procedure.

Resection of Giant Invasive Parasagittal Atypical Meningioma With a Venous Graft Reconstruction of the Sagittal Sinus: 2-Dimensional Operative Video.

Parasagittal meningioma becomes challenging when it involves the sagittal sinus and frequently invades the skull1; hence, resection of the invasive bone and management of the involved sinus are the two crucial issues in these tumors; notwithstanding the practice of conservative surgical resection coupled with irradiation (radiosurgery or stereotactic radiotherapy),2 radical surgical removal, including the invaded bone and sinus (Simpson grade I), alleviates recurrences. It is more valuable and particularly recommended in grade II meningiomas,3 since radical surgery is the principal factor in a long control of grade II meningioma4 and radiation effectiveness is directly related to gross total removal.5 On the other hand, removal of tumor involving the sinus and sinus reconstruction has been recommended and practiced for years.6-10 When the sinus is occluded, preservation of the collateral venous drainage becomes paramount.11 If the collateral venous drainage included cutaneous and dural channels, as in this patient, reconstructing of the sinus would become preventative of a major venous complication. Sindou et al8 even advocate the routine reconstruction of occluded sinus to minimize morbidity. The patient is 39 yr old with a giant parasagittal meningioma that invaded the skull, occluded the sinus at the mid-third, and had venous collateral through the dura and cutaneous veins. He underwent radical resection with reconstruction of the sinus by saphenous vein graft. Patient consented for the operation and publication of images. Illustrations at 1:51 and 2:15 from Al-Mefty O, Operative Atlas of Meningiomas, © LWW, 1997, with permission.

"Save the Nerve": Technical Nuances for Hearing Preservation and Restoration in Vestibular Schwannoma Surgery: 2-Dimensional Operative Video.

Hearing loss is a significant disability that inflects dysfunction and affects the patient quality of life. Consequently, hearing preservation and the potential of hearing restoration are prized quests in the management of vestibular schwannoma.1 Although small intracanalicular vestibular schwannomas are commonly observed, progressive hearing loss occurs despite the absence of tumor growth; hence, surgical resection can be performed with the sole aim of hearing preservation in well-informed and eager patients. Hearing preservation by surgical resection has proven to be durable.1-4 In this group of patients, we concur with Yamakami et al2 that vascularized meatal flap to reconstruct the canal helps prevent scarring of the cochlear nerve and provides cerebrospinal fluid (CSF) bathing to the cochlear nerve, yielding better long-term hearing preservation. With larger tumors and more severe hearing loss at presentation, microsurgical resection should aim at preserving the cochlear nerve, a goal frequently achievable, which offers the potential for hearing restoration with cochlear implants.3 The results of cochlear implants in restoration of severe hearing loss have been to say the least most impressive.5 We demonstrate these 2 frequently encountered clinical situations with 2 surgical videos showing specific surgical tenets, including intra-arachnoidal dissection, medial to lateral manipulation of the tumor, preservation of the labyrinthine artery, as well as reconstruction of the internal auditory canal.2,3,6,7 The patients consented to the surgery and to the publication of their picture in a surgical video. Illustration in video © 1997 O. Al-Mefty. Used with permission. All rights reserved.

Diaphragm Sellae Meningioma: Distinct Clinical, Anatomic, and Surgical Considerations: 2-Dimensional Operative Video.

Nestled in the parasellar region, surrounded by critical neurovascular structures, diaphragm sellae meningiomas although rare present distinct clinical, radiological, and surgical considerations.1-3 Consequently, they present surgical challenges that could be overcome with technical nuances. The origin of this meningioma on the diaphragm creates a distorted anatomy, which must be comprehended for the safe approach and resection. Three distinct subtypes of diaphragm sellae meningiomas are described, each with distinctive clinical presentations and surgical treatment implications.2 Type A originates from the upper leaf of diaphragm sellae pushing the stalk posteriorly. It usually presents with unilateral visual loss. Type B originates from the upper leaf of the diaphragm sellae pushing the stalk anteriorly. It presents with few visual symptoms, but memory disturbance and hypopituitarism are common. Type C originates from the inferior leaf of the diaphragm sellae (intrasellar meningioma) presenting with bitemporal hemianopsia and hypopituitarism. Recognizing these variations in this rare tumor subtype is critical to minimizing potential adverse outcomes associated with operative treatment. The cranial approach has been the recommended route for these lesions with an exception of the intrasellar type.1,3 In this article, we depict the pathological anatomy and demonstrate the surgical nuances in handling diaphragm sellae meningioma resection through a cranio-orbital approach4 in a patient who had an unsuccessful trans-sphenoidal resection attempt. The patient consented for the procedure. Image at 1:38 from Al-Mefty O, Operative Atlas of Meningiomas, © LWW, 1997, with permission. Image at 8:56 from Kinjo et al,2 Diaphragma sellae meningiomas, case reports, Neurosurgery, 1995, 36(6), 1082-1092, by permission of the Congress of Neurological Surgeons.

Nuances of Olfactory Groove Meningioma Surgery: 2-Dimensional Operative Video.

Olfactory groove meningiomas frequently present as large or giant-size tumors associated with marked frontal lobe edema and significant frontal lobe dysfunction. Simpson grade I removal was rare in early reports due to their invasion of the ethmoid sinuses and skull base bone,1 which resulted in high recurrence rates.2,3 Indeed, recurrence occurred in the most celebrated case of olfactory groove meningioma.4,5 To achieve Simpson grade I removal (tumor, dura, bone), protect the frontal lobes from additional injury, and provide the best chance for recovery, we demonstrate a few nuances for olfactory groove meningioma surgery: Utilizing a skull base approach with a low dural opening, the frontal veins are preserved, and the frontal lobe is protected from retraction, manipulation, and venous injury. By the time of diagnosis, although the patient's olfaction is often absent, there still remains a role to preserve at least 1 olfactory tract, which might yield some preservation in a limited number of patients. Emphasis has been rightly made on the preservation of the A2 segments, which can be dissected using microsurgical technique. Lastly, multilayer reconstruction of the skull base is required, using an inlay graft, resting on a vascularized pericranial flap, and occlusion of the sinuses with a fat graft. The endonasal endoscopic approach has fallen out of favor due to limitations for complete tumor resection and higher complication rates.6 We present a case of a relatively small olfactory groove meningioma in a 36-yr-old male with partial olfactory loss. The patient consented for surgery. Images at 2:07, 2:29, and 2:54 from Al-Mefty O, Operative Atlas of Meningiomas, © LWW, 1997, with permission. Image at 8:31 public domain by age.