Trigeminal Nerve Schwannoma of the Cerebellopontine Angle.

Introduction  Large and even moderate sized, extra-axial cerebellopontine angle (CPA) tumors may fill this restricted space and distort the regional anatomy. It may be difficult to determine even with high resolution magnetic resonance imaging (MRI) if the tumor is dural-based, or what the nerve of origin is if a schwannoma. While clinical history and exam are helpful, they are not unequivocal, particularly since many patients present with a myriad of symptoms, or conversely an incidental finding. We present an atypical appearing, asymptomatic CPA tumor, ultimately identified at surgery to be a trigeminal schwannoma. Case History  A 40-year-old man presented with new-onset seizure. MRI identified an incidental heterogeneously contrast-enhancing CPA lesion ( Fig. 1A - D ). The tumor was centered on the internal auditory canal (IAC) with no tumor extension into Meckel's cave, IAC or jugular foramen. Audiometry demonstrated 10db of relative left-sided hearing loss with 100% word recognition. Physical examination was negative for focal neurologic deficits. A retrosigmoid craniotomy was performed and an extra-axial, yellow-hued mass was encountered and resected, which was ultimately confirmed to originate from the trigeminal nerve ( Video 1 ). Gross total resection was achieved, and the patient recovered from surgery with partial ipsilateral trigeminal sensory loss and no other new neurologic deficits. Conclusion  Pure CPA trigeminal schwannomas are rare, but should be considered in the differential for enhancing CPA lesions. Although, Meckel's cave involvement is frequently observed, it is not universal, and pure CPA schwannomas of all cranial nerves IV-XII have been reported in the literature. The link to the video can be found at: https://youtu.be/AlodYCu70F8

Fourth-generation bypass and flow reversal to treat a symptomatic giant dolichoectatic basilar trunk aneurysm

BACKGROUND: Giant dolichoectatic basilar trunk aneurysms have an unfavorable natural history and are associated with high morbidity, but their neurosurgical treatment is complex and challenging. METHODS: Flow reversal reconstruction with fourth-generation bypass and proximal vertebral artery clip occlusion is performed via orbitozygomatic craniotomy with the Kawase approach under rapid ventricular pacing. CONCLUSION: Fourth-generation bypass is an innovative, technically challenging, and clinically effective tool in the treatment armamentarium for giant dolichoectatic basilar trunk aneurysms

Double-Interposition Bypass: Technical Case Report of a Novel Intraoperative Bypass Salvage Technique

BACKGROUND AND IMPORTANCE: Complex cerebrovascular bypass operations may confer an increased risk of intraoperative complications, such as graft thrombosis. Novel techniques are needed to optimize the management of these challenging cases. CLINICAL PRESENTATION: A woman in her late 20s was incidentally diagnosed with a 1.5-cm basilar apex aneurysm, which grew to 3.5 cm over 2 years of active surveillance. Definitive treatment was then recommended with flow reversal and Hunterian ligation of the basilar trunk planned as a radial artery graft (RAG) bypass: M2 (S-Ec) RAG (E-Sc*) P2. Intraoperative graft thrombosis prompted multiple attempted salvage maneuvers; however, complete excision and repeat anastomosis were ultimately required. The procedure was completed using a novel double-interposition technique, with ligation of the index RAG approximately 1 cm proximal to the distal anastomosis (final bypass: M2 [S-Ec*] RAG [E-Ec*] RAG\u27 [E-Sc] P2). These technical modifications yielded a less deep recipient site for the repeat bypass and an end-to-end anastomosis rather than an end-to-side anastomosis, collectively facilitating a more efficient and facile salvage. The patient recovered well from surgery, and flow reversal was successfully achieved within the aneurysm. CONCLUSION: Despite the increased risk of intraoperative thrombosis with complex cerebrovascular bypass operations, facility with salvage techniques can lead to technically and clinically excellent outcomes. We report the successful use of a novel fourth-generation double-interposition bypass that shortens the working distance and uses a more favorable anastomosis technique. This bypass may facilitate safe and efficient microsurgery in patients who require complete revision of an intracranial-intracranial construct

Synchronous Presentation of a Cervical Spinal Schwannoma and Primary Progressive Multiple Sclerosis in a 65-year-old Man.

Schwannomas are common benign neoplasms of the myelinating cells surrounding peripheral nerve axons. Though uncommon, lesions arising in the cervical spine may produce radicular pain and myelopathic weakness. Multiple sclerosis (MS) is a common autoimmune disorder with the capacity to mimic nearly any neurologic disease, including spinal cord neoplasms. We report the third case of synchronously presenting primary progressive MS and spinal schwannoma. A 65-year-old man presented with six months of progressive weakness and pain of the right shoulder, forearm, and hand. MRI demonstrated a contrast-enhancing transforaminal lesion at C7, most consistent with a benign nerve sheath tumor. Additional history disclosed several years of worsening fatigue, accompanied by bilateral weakness and lancinating leg pain. MRI of the neuraxis demonstrated abnormalities consistent with chronic demyelinating disease intracranially and within the spinal cord; cerebrospinal fluid (CSF) analysis revealed nine oligoclonal bands and an elevated IgG index, resulting in the diagnosis of MS. Given the symptomatic C7 lesion, the patient subsequently underwent right C6-C7 facetectomy, gross total resection of the tumor, and C6-T1 posterior instrumented fusion. Postoperatively, the patient rapidly recovered normal right upper extremity function, and pathology confirmed benign schwannoma. Synchronously presenting co-morbid neurologic diagnoses are exceedingly rare. Nonetheless, the high incidence and protean nature of MS make it particularly susceptible to such confounding clinical cases. Correspondingly, MS should be considered when neurologic abnormalities are not compatible with a focal radiographic lesion, and the present report emphasizes the value of a good history and exam in unraveling similarly challenging cases

Spinal Dorsal Intradural Arteriovenous Fistulae: Natural History, Imaging, and Management

In this review, we describe the pathophysiology, diagnosis, and treatment of spinal dorsal intradural arteriovenous fistulae (DI-AVFs), focusing on novel research areas. DI-AVFs compose the most common subgroup of spinal arteriovenous lesions and most commonly involve the thoracic spine, followed by lumbar and sacral segments. The pathogenesis underlying DI-AVFs is an area of emerging understanding, thought to be attributable to venous congestion and hypertension that precipitate ascending myelopathy. Patients with DI-AVFs typically present with motor, sensory, or urinary dysfunction, although a wide swath of other less common symptoms has been reported. DI-AVFs can be subdivided by spinal region, which in turn is associated with 4 distinct clinical phenotypes: craniocervical junction (CCJ), subaxial cervical, thoracic, and lumbosacral. Patients with CCJ and lumbosacral DI-AVFs have particularly interesting presentations and treatment considerations. High-value diagnostic findings on magnetic resonance imaging include flow voids, missing-piece sign, and T2-weighted intramedullary hyperintensity. However, digital subtraction angiography is the gold standard for diagnosis and localization of DI-AVFs, as well as for definitive treatment planning. Surgical disconnection of DI-AVFs is almost universally curative and frontline treatment especially for CCJ and lumbosacral DI-AVFs. Endovascular techniques evolve in promising ways, such as improved visualization, distal access, and liquid embolic techniques. The pathophysiology of DI-AVFs is better understood using newly identified radiological diagnostic markers. Despite new techniques and devices introduced in the endovascular field, surgery remains the gold-standard treatment for DI-AVFs