Endovascular Mechanical Thrombectomy for Right Hemispheric Stroke Syndrome Due to Acute Left A1-A2 Junction Thromboembolic Occlusion.

Background: Endovascular mechanical thrombectomy (EVT) for large vessel occlusions has had a dramatic impact on the management of acute ischemic stroke. Extended use of EVT beyond American Heart Association guidelines has been successful in carefully selected cases. Case Report: A 71-year-old male presented to our comprehensive stroke center upon awakening with mild left hemiparesis. He was found to have a chronic occlusion of the right supraclinoid segment of the internal carotid artery. Angiography demonstrated large vessel occlusion of the contralateral A1-A2 junction that was successfully recanalized. Imaging at 24 hours displayed no evidence of infarct, the patient rapidly improved during hospitalization, and he was discharged on postoperative day 7 with a National Institutes of Health Stroke Scale score of zero. Conclusion: We describe successful EVT of a patient presenting with false-localizing symptoms consistent with a right hemispheric acute ischemic stroke secondary to left A1-A2 junction large vessel occlusion. This case demonstrates the importance of a high index of suspicion when evaluating atypical stroke presentations and the effectiveness of EVT in the treatment of distal small-caliber vessels.

Diffusely invasive supratentorial rosette-forming glioneuronal tumor: illustrative case.

BACKGROUND: Rosette-forming glioneuronal tumors (RGNTs) are rare tumors composed of mixed glial and neurocytic components. Most lesions are confined to the posterior fossa, especially in the region of the fourth ventricle, in young adults. In few instances, diffuse involvement of the supratentorial region is identified, thereby creating significant challenges in diagnosis, surgical intervention, and prognostication. OBSERVATIONS: The authors present a 23-year-old female with chronic headaches, papilledema, and hydrocephalus who underwent radiographic evaluation revealing obstructive hydrocephalus and diffuse supratentorial enhancing and nonenhancing cystic and nodular lesions. The patient underwent a right frontal craniotomy and septostomy. An exophytic nonenhancing right frontal horn lesion was resected, and an enhancing third-ventricular lesion was biopsied. Final pathology of both of the lesions sampled was consistent with RGNT. Next-generation sequencing demonstrated tumor alterations in the FGFR-1 and PIK3CA genes. Targeted therapy with the FGFR inhibitor erdafitinib demonstrated a partial remission. LESSONS: Diffuse supratentorial spread of RGNT is an extremely rare presentation of an already uncommon pathology. In some cases, gross-total resection may not be feasible. Goals of surgery include acquiring tissue for diagnosis, maximizing safe resection, and treating any associated hydrocephalus. FGFR inhibitors may be of benefit in cases of disease progression.

The Longissimus Capitis Insertion as a Superficial Landmark for the Sigmoid Sinus: An Anatomical Study.

Objective Many external anatomical landmarks have been used for approximating deeper, intracranial structures. Herein, we evaluate the attachment of the longissimus capitis (LC) on the mastoid process as a landmark for the underlying sigmoid sinus. Methods Adult cadavers underwent dissection of the posterior occiput with special attention to the attachment of the LC muscle. Once the periphery of the muscle's tendon of attachment was determined, a burr hole was made in this area and evaluated internally for its relationship to the sigmoid sinus. Results From an intracranial view, burr holes on all sides were over the sigmoid sinus and just slightly lateral to the center of the sinus. The distance from the midline to the medial border of the insertion of the LC had a mean of 63.0 ± 7.2 mm. The width of the tendon of insertion of the LC on the mastoid process had a mean of 17.6 ± 5.7 mm. The length of the tendon insertion of the LC had a mean of 14.7 ± 4.7 mm. The distance from the inferior border of the insertion of the LC to the tip of the mastoid process had a mean of 6.2 ± 4.5 mm. Conclusion To our knowledge, use of the attachment site of the LC on the mastoid process as an external landmark for the underlying sigmoid sinus has not previously been reported. Based on our cadaveric findings, the sigmoid sinus is centered under the attachment of the LC regardless of the width of its tendon.

Detethering the superficial temporal artery: Application to tension free superficial temporal artery-middle cerebral artery bypasses.

Extracranial-intracranial bypass has been shown to be effective in the surgical treatment of moyamoya disease, complex aneurysms, and tumors that involve proximal vasculature in carefully selected patients. Branches of the superficial temporal artery (STA) are used commonly for the bypass surgery; however, an appropriate length of the donor vessel must be harvested to avoid failure secondary to anastomotic tension. The goal of this cadaveric study was to investigate quantitatively operative techniques that can increase the STA length available to facilitate tension-free STA-middle cerebral artery (MCA) bypass. We conducted a cadaveric study using a total of 16 sides in eight cadavers. Measurements of the STA trunk with its frontal branch (STAfb) were taken before and after skeletonization and detethering of the STA with the STAfb and mobilization of the parietal branch of the STA. A final measurement of the STA with the STAfb was taken for the free length gained toward visible proximal cortical branches of the MCA. Paired student's t-tests were used to compare the mean length before and after mobilization and unpaired t-tests to analyze according to laterality. The mean length of the STA with the STAfb was 9.0 cm prior to modification. After skeletonization and mobilization, the mean lengths increased significantly to 10.5 and 11.3 cm, respectively (p < 0.05). Especially in the cases that had the coiled and tortuous STA, skeletonization was considerably effective to increase the length of the STA with the STAfb. After simulating a bypass by bringing the STAfb to the recipient MCA site, the mean extended length of the STA with the STAfb was 3.0 cm. There were no statistically significant differences between sides in all measurements. We report a significant increase in the mean STA length available (3.0 cm) following skeletonization and mobilization. Clinical applications of the extended length of the STA with the STAfb may facilitate tension-free STA-MCA bypasses and improve outcomes. Further studies are needed in a clinical context.

Vertebral artery dissection and associated ruptured intracranial pseudoaneurysm successfully treated with coil assisted flow diversion: A case report and review of the literature.

Dissecting intracranial pseudoaneurysms (IPs) are associated with a high incidence of rupture and poor neurologic outcomes. Lesions in the posterior circulation are particularly malignant and pose even greater management challenges. Traditional management consists of microsurgical vessel sacrifice with or without bypass. Flow diversion (FD) in the setting of subarachnoid hemorrhage (SAH) represents a reconstructive treatment option and can be paired with coil embolization to promote more rapid thrombosis of the lesion. We report a case of a ruptured dissecting vertebral artery (VA) IP successfully acutely treated with coil-assisted FD. A 53-year-old male presented with a right V4 dissection spanning the origin of the posterior inferior cerebellar artery and associated ruptured V4 IP. The patient was treated with coil-assisted FD. Oral dual-antiplatelet therapy (DAPT) was initiated during the procedure, and intravenous tirofiban was used as a bridging agent. Immediate obliteration of the IP was achieved, with near-complete resolution of the dissection within 48 h. The patient made a complete recovery, and angiography at 6 weeks confirmed total IP obliteration, reconstruction of the VA, and a patent stent. The use of FD and DAPT in the setting of acute SAH remains controversial. We believe that coil-assisted FD in carefully selected patients offers significant advantages over traditional microsurgical and endovascular options. The risks posed by DAPT and potential for delayed thrombosis with FD can be effectively mitigated with planning and the development of protocols. We discuss the current literature in the context of our case and review the challenges associated with treating these often devastating lesions.

Middle Fossa Encephaloceles Treated via the Transmastoid Approach: A Case Series and Review of the Literature.

BACKGROUND: Middle fossa (MF) encephaloceles are rare lesions resulting from herniation through defects in the tegmen tympani or mastoideum. Underlying etiologies and clinical presentations are variable. Surgical goals include fistula obliteration, resection of nonfunctioning parenchyma, and dehiscence repair. The middle cranial fossa approach (MCFA), transmastoid approach (TMA), and combined (MCFA + TMA) approaches have been described. The minimally invasive TMA provides excellent exposure of the pathology and allows for ample working room to repair the defect. OBJECTIVE: To present short-term follow-up results in patients treated via the TM repair at our institution. METHODS: A retrospective review of patients with symptomatic encephaloceles treated via the TMA by our multidisciplinary team. Patient demographics, clinical presentations, intraoperative findings, repair technique, and outcomes were highlighted. RESULTS: A total of 16 encephaloceles in 13 patients were treated. Defect etiologies included spontaneous (50.0%), secondary to chronic infection (25.0%), or cholesteatoma (18.8%). Defects were most often within the tegmen mastoideum (68.8%). Average length of surgery was 3.3 h (95% CI: 2.86-3.67) and length of stay 3.9 d (95% CI: 3.09-4.79). On short-term follow-up (average 11.5 mo), no patients experienced postoperative cerebrospinal fluid leak or recurrence. The majority of patients (83.3%) experienced confirmed improvement or stabilization of hearing. CONCLUSION: MF encephaloceles present with various clinical manifestations and result from multiple underlying etiologies. The TMA is an alternative to craniotomy and our short-term results suggest that this approach may be utilized effectively in appropriately selected cases.

Iatrogenic Middle Cerebral Artery Ruptured Pseudoaneurysm Successfully Treated With a Pipeline Embolization Device.

Background: Endovascular advances have shifted the treatment algorithms for traumatic intracranial pseudoaneurysms (IPs) from vessel sacrifice to reconstruction. The Pipeline embolization device (PED) is a flow-diverting stent that promotes endothelialization across the lesion and reconstitutes the parent vessel lumen. Case Report: A 66-year-old male with a history of a right orbital apex lesion presented for biopsy with ophthalmology. Ophthalmology performed a right lateral orbitotomy complicated by brisk arterial bleeding from a proximal right middle cerebral artery (MCA) pseudoaneurysm. The MCA pseudoaneurysm was treated endovascularly with a PED, resulting in immediate stasis of contrast within the lesion without compilation. Interval follow-up angiograms 6 weeks and 6 months after the procedure showed no evidence of recurrence and a widely patent stent. Conclusion: The PED provided a rapid, minimally invasive, and durable treatment option for an acutely ruptured IP. We illustrate that endovascular management with flow diversion can be effectively used in select cases and provides a way to reconstruct the damaged vessel lumen and obliterate the aneurysm.

Transradial access for anterior circulation deployment of pipeline embolization device: A case report, literature review, and technical note.

Common femoral artery (CFA) transfemoral access (TFA) has been the traditional route for neuroendovascular intervention with flow diversion including the pipeline embolization device (PED) for the treatment of wide-necked aneurysms. Successful deployment requires significant catheter support, thus making alternative access challenging. A 56-year-old-female presented with subarachnoid hemorrhage secondary to a large ruptured posterior communicating artery (PCOM) aneurysm as well as found to have an unruptured left superior cerebellar artery (SCA) aneurysm. Endovascular embolization of PCOM aneurysm via TFA was complicated by a right CFA pseudoaneurysm. The SCA aneurysm was treated 8 weeks later via left TFA with consequent development of a left CFA pseudoaneurysm. Contrasted magnetic resonance angiography revealed recurrence at the neck of the PCOM aneurysm at 4-month follow-up, treated via transradial access (TRA) PED flow diversion to avoid additional groin complications. Anatomic, procedural, and clinical considerations for TRA anterior circulation flow diversion using the PED are reviewed.

Anatomical Considerations for Endovascular Intervention for Extracranial Carotid Disease: A Review of the Literature and Recommended Guidelines.

Patient selection for endovascular intervention in extracranial carotid disease is centered on vascular anatomy. We review anatomical considerations for non-traumatic disease and offer guidelines in patient selection and management. We conducted a systematic literature review without meta-analysis for studies involving anatomical considerations in extracranial carotid intervention for non-traumatic disease. Anatomical considerations discussed included aortic arch variants, degree of vessel stenosis, angulation, tortuosity, and anomalous origins, and atheromatous plaque morphology, composition, and location. Available literature suggests that anatomical risks of morbidity are largely secondary to increased procedural times and difficulties in intervention system delivery. We recommend the prioritization of endovascular techniques on an individual basis in cases where accessible systems and surgeon familiarity provide an acceptable likelihood of rapid access and device deployment.

Multiple flow-related intracranial aneurysms in the setting of contralateral carotid occlusion: Coincidence or association?

The prevalence of intracranial aneurysms (IAs) is higher in patients with internal carotid artery (ICA) stenosis, likely due to alterations in intracranial hemodynamics. Severe stenosis or occlusion of one ICA may result in increased demand and altered hemodynamics in the contralateral ICA, thus increasing the risk of contralateral IA formation. In this article, we discuss a relevant case and a comprehensive literature review as it pertains to the association of ICA stenosis and IA. Our patient was a 50-year-old female with a chronic asymptomatic right ICA occlusion who presented with diffuse subarachnoid hemorrhage. Emergent angiography revealed left-sided A1-A2 junction, paraclinoid, left middle cerebral artery (MCA) bifurcation, and left anterior temporal artery aneurysms. Brisk filling of the right anterior circulation through the anterior communicating artery was also identified, signifying increased demand on the left ICA circulation. Complete obliteration of all aneurysms was achieved with coil embolization and clipping. For our literature review, we searched the PubMed and EMBASE databases for case reports and case series, as well as references in previously published review articles that described patients with concurrent aneurysms and ICA stenosis. We selected articles that provided adequate information about the case presentations to compare aneurysm and patient characteristics. Our review revealed a higher number of patients with multiple aneurysms contralateral (25%) to rather than ipsilateral to (6%), the ICA stenosis. We discuss the pathogenesis and management of multiple flow-related IA in the context of the existing literature related to concurrent ICA stenosis and IA.

Cell Culture Model to Study Cerebral Aneurysm Biology.

Mechanisms governing cerebral aneurysm (CA) formation, progression, and rupture remain incompletely understood. However, understanding such mechanisms is critical to improving treatment for patients harboring CA. In vitro studies facilitate dissecting molecular mechanisms underlying vascular pathology and allow screening of therapies that can be subsequently explored in vivo. Cerebral vascular smooth muscle cells (VSMC) are an important constituent of the vessel wall, and phenotypic modulation of these cells to a pro-inflammatory, pro-matrix remodeling phenotype appears to be important in CA pathology. We have taken a reductionist approach using cultured cerebral VSMC to further explore CA biology. We describe techniques for culturing cerebral VSMC and outline experimental approaches incorporating these cells to study CA biology.

Treatment with dimethyl fumarate reduces the formation and rupture of intracranial aneurysms: Role of Nrf2 activation.

Oxidative stress and chronic inflammation in arterial walls have been implicated in intracranial aneurysm (IA) formation and rupture. Dimethyl fumarate (DMF) exhibits immunomodulatory properties, partly via activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway which reduces oxidative stress by inducing the antioxidant response element (ARE). This study evaluated the effects of DMF both in vitro, using tumor necrosis factor (TNF)-α-treated vascular smooth muscle cells (VSMC), and in vivo, using a murine elastase model to induce aneurysm formation. The mice were treated with either DMF at 100 mg/kg/day P.O. or vehicle for two weeks. DMF treatment protected VSMCs from TNF-α-induced inflammation as demonstrated by its downregulation of cytokines and upregulation of Nrf2 and smooth muscle cell markers. At higher doses, DMF also inhibited the pro-proliferative action of TNF-α by increasing apoptosis which protected the cells from aponecrosis. In mice, DMF treatment significantly decreased the incidence of aneurysm formation and rupture, at the same time increasing Nrf2 levels. DMF demonstrated a neuroprotective effect in mice with a resultant inhibition of oxidative stress, inflammation, and fibrosis in the cerebrovasculature. This suggests a potential role for DMF as a rescue therapy for patients at risk for formation and rupture of IAs.

Cauda Equina Syndrome Secondary to Diffuse Infiltration of the Cauda Equina by Acute Myeloid Leukemia: Case Report and Literature Review.

BACKGROUND: Cauda equina syndrome (CES) results from the dysfunction of the lumbar, sacral, and coccygeal rootlets composing the cauda equina. The underlying etiology is most commonly compression secondary to a large herniated lumbosacral disk; however, any pathology affecting the rootlets can result in the syndrome. METHODS: We present a rare case of CES secondary to neoplastic polyradiculitis in a patient with acute myelogenous leukemia (AML) and review the pertinent literature. A 72-year-old male with a medical history of AML presented with 2 weeks of difficulty ambulating, followed by acute-onset low back pain radiating to the buttocks bilaterally. RESULTS: Imaging of the lumbar spine demonstrated diffuse enhancement and thickening of the cauda equina rootlets. Lumbar puncture showed numerous blasts with monocytoid features consistent with AML, and the patient was diagnosed with polyradiculopathy of the cauda equina secondary to diffuse metastatic infiltration. CONCLUSIONS: Central nervous system involvement of leukemia is poorly understood, even though such lesions are not uncommon in advanced disease. As treatment has improved, many types of leukemia, such as AML, are believed to be curable, and patients with the disease are living longer. With improved survival, it is reasonable to suspect that such involvement by AML may become more common. Our patient is a classic presentation of CES secondary to diffuse infiltration by AML and serves as an example of this rare manifestation of hematologic malignancy.

Arteriovenous Fistula of the Filum Terminale: A Case Report and Review of the Literature.

BACKGROUND: Fistulas of the filum terminale are rare lesions that result from a fistulous connection between the artery and vein of the filum terminale. These lesions often present as progressive thoracic myelopathy secondary to venous hypertension that is transmitted to the coronal venous plexus of the spinal cord. Frequently, filum fistulas will be associated with lumbar stenosis and likely form as a result of chronic inflammation and compression. However, owing to the relative rarity of filum fistulas and the commonality of lumbar stenosis, the presence of a filum fistula could be overlooked or misdiagnosed. CASE DESCRIPTION: We have presented the case of a 62-year-old man with severe lumbar stenosis who had presented with progressive thoracic myelopathy. The evaluation, including spinal angiography, identified a low-flow arteriovenous fistula within the filum terminale that was successfully treated with microsurgical obliteration. The patient tolerated the procedure well, with good functional recovery within 1 month. CONCLUSION: Just as was the case with our patient, these lesions demonstrate a high association with lumbar stenosis and tethered or tight cord syndrome. We reviewed the clinical presentation, imaging findings, surgical management, and possible mechanisms of development for these rarely encountered fistulas.