Transcallosal Retroforniceal Transchoroidal Approach: To the Posterior Third Ventricle and Beyond.

BACKGROUND: The transcallosal retroforniceal transchoroidal approach represents an advanced neurosurgical technique that allows access to lesions located within the posterior third ventricle and mesencephalon. It relies on a comprehensive understanding of microsurgical anatomy and embryology, integrating modern neurosurgical operative techniques to minimize retraction and injury to the normal neuronal structures. METHODS: We report the cases of two patients undergoing treatment via this approach, one presenting with a thalamic cavernoma and the other with cystic low-grade glioma of the midbrain. RESULTS: In these 2 cases, the decision to use the transcallosal approach was mainly due to improved trajectory, gravitational retraction of the hemisphere, and improved delivery of the lesion into the operative field by gravity alone. CONCLUSION: Through a detailed description of the surgical approach and anatomy, we illustrate the feasibility of the transcallosal retroforniceal transchoroidal approach for accessing lesions located deeply in the brain.

Single Vessel Double Anastomosis for Flow Augmentation - A Novel Technique for Direct Extracranial to Intracranial Bypass Surgery.

BACKGROUND: A double anastomosis using a single superficial temporal artery (STA) donor branch for both a proximal side-to-side (S2S) and a distal end-to-side anastomosis is a novel direct bypass technique for use in selected patients necessitating flow augmentation. OBJECTIVE: To describe the single-vessel double anastomosis (SVDA) technique, including its indications, advantages, and limitations, in addition to reporting our cases series of patients who underwent a SVDA bypass surgery. METHODS: Patients undergoing a SVDA bypass at a single institution between January 2010 and February 2016 were retrospectively reviewed. Intraoperative flow data was collected, including STA cut-flow, bypass flows, and cut flow index (CFI). Bypass patency was assessed by cerebral angiography and quantitative magnetic resonance angiography with noninvasive optimal vessel analysis. Adverse events occurring during the hospital stay and clinical status at last follow up was recorded. RESULTS: Seven patients underwent SVDA bypass. Mean follow-up was 14.5 mo. Initial CFI for the S2S bypasses averaged 0.56 ± 0.25 and CFI after the SVDA averaged 1.15 ± 0.24. There was a statistically significant average difference in CFI before and after the SVDA bypass (p < .013). Thirteen bypasses (93%) were patent postoperatively, and remained patent at last follow up. Four patients experienced various postoperative complications. None of the patients had a new stroke since hospital discharge. CONCLUSION: SVDA is a novel technique that can be advantageous for selected cases of extracranial-to-intracranial bypass. Expertise in bypass procedures is a necessary prerequisite. Graft patency rates and complications appear comparable to other bypass techniques.

Side-to-Side and End-to-Side Double Anastomosis Using the Parietal-Branch of the Superficial Temporal Artery-A Novel Technique for Extracranial to Intracranial Bypass Surgery: 3-Dimensional Operative Video.

In this 3-dimensional video, we perform a side-to-side and end-to-side double anastomosis using the parietal-branch of the superficial temporal artery (STA) to provide flow augmentation in a symptomatic 59-yr-old male with bilateral internal carotid artery occlusion at the origin, and left M1 segment occlusion. The patient suffered multiple left hemispheric strokes despite maximal medical therapy and was found to have poor hemodynamic reserve in the left hemisphere during evaluation with regional and global blood oxygenation level-dependent functional magnetic resonance imaging with CO2-challenge as well as quantitative magnetic resonance angiography and noninvasive optimal vessel analysis pre- and post-acetazolamide challenge. Postoperatively, the patient did very well and his hemodynamic studies improved significantly. The importance of this technique relies on the fact that we are using a single donor vessel to perform 2 anastomoses, and carries the following advantages: (1) the frontal STA branch remains intact and therefore can still be used at a later time if further revascularization is needed; (2) wound complications related to devascularizing the scalp from harvesting both STA branches are reduced; (3) 2 vascular territories are augmented (frontal and temporal) while using a single donor; (4) we are maximizing donor potential and optimizing cut flow index (CFI; total bypass flow postanastomosis divided by bypass cut flow) by flow augmenting 2 separate vascular beds therefore increasing demand. To explain that fourth point further: if the STA donor is able to carry a maximum 100 mL/min when cut, and after performing the first anastomosis bypass flow is only 37 mL/min, CFI will be 37/100 = 0.37, reflecting low demand, a poor indicator of graft patency, as previously published.1,2 By adding a second anastomosis which demands an additional 60 mL/min from the same STA donor, CFI (60 + 37)/100 improves to 1. Institutional Review Board approval was obtained for the review of patient chart and video files. Informed consent was obtained directly from the patient via telephone regarding use of media for educational and publication purposes.

Spinal epidural abscess in a patient with piriformis pyomyositis.

BACKGROUND: Spinal epidural abscess resulting from piriformis pyomyositis is extremely rare. Such condition can result in serious morbidity and mortality if not addressed in a timely manner. CASE DESCRIPTION: The authors describe the case of a 19-year-old male presenting with a 2-week history of fever, low back pain, and nuchal rigidity. When found to have radiographic evidence of a right piriformis pyomyositis, he was transferred to our institution for further evaluation. Because he demonstrated rapid deterioration, cervical, thoracic, and lumbar magnetic resonance imaging scans were emergently performed. They revealed an extensive posterior spinal epidural abscess causing symptomatic spinal cord compression extending from C2 to the sacrum. He underwent emergent decompression and abscess evacuation through a dorsal midline approach. Postoperatively, he markedly improved. Upon discharge, the patient regained 5/5 strength in both upper and lower extremities. Cultures from the epidural abscess grew methicillin-sensitive Staphylococcus aureus warranting a 6-week course of intravenous nafcillin. CONCLUSION: A 19-year-old male presented with a holospinal epidural abscess (C2 to sacrum) originating from piriformis pyomyositis. The multilevel cord abscess was emergently decompressed, leading to a marked restoration of neurological function.

Novel imaging approaches to cerebrovascular disease.

Imaging techniques available to the physician treating neurovascular disease have substantially grown over the past several decades. New techniques as well as advances in imaging modalities continuously develop and provide an extensive array of modalities to diagnose, characterize, and understand neurovascular pathology. Modern noninvasive neurovascular imaging is generally based on computed tomography (CT), magnetic resonance (MR) imaging, or nuclear imaging and includes CT angiography, CT perfusion, xenon-enhanced CT, single-photon emission CT, positron emission tomography, magnetic resonance angiography, MR perfusion, functional magnetic resonance imaging with global and regional blood oxygen level dependent imaging, and magnetic resonance angiography with the use of the noninvasive optional vessel analysis software (River Forest, Ill). In addition to a brief overview of the technique, this review article discusses the clinical indications, advantages, and disadvantages of each of those modalities.

Increased prevalence and rupture status of feeder vessel aneurysms in posterior fossa arteriovenous malformations.

BACKGROUND: Posterior fossa arteriovenous malformations (AVMs) are considered to have a higher risk of poor outcome, as are AVMs with associated aneurysms. We postulated that posterior fossa malformations may be more prone to associated feeder vessel aneurysms, and to aneurysmal source of hemorrhage. OBJECTIVE: To examine the prevalence and hemorrhagic risk of posterior fossa AVM-associated feeder vessel aneurysms. METHODS: A retrospective review of AVMs was performed with attention paid to location and presence of aneurysms. The hemorrhage status and origin of the hemorrhage was also reviewed. RESULTS: 571 AVMs were analyzed. Of 90 posterior fossa AVMs, 34 (37.8%) had aneurysms (85% feeder vessel, 9% intranidal, 15% with both). Of the 481 supratentorial AVMs, 126 (26.2%) harbored aneurysms (65% feeder vessel, 29% intranidal, 6% both). The overall incidence of feeder aneurysms was higher in posterior fossa AVMs, which were evident in 34.4% of infratentorial AVMs compared to 18.5% of supratentorial malformations (p<0.01). The presence of intranidal aneurysms was similar in both groups (9.2% vs 8.8%). Feeder artery aneurysms were much more likely to be the source of hemorrhage in posterior fossa AVMs than in supratentorial AVMs (30% vs 7.6%, p<0.01). CONCLUSIONS: Posterior fossa AVMs are more prone to developing associated aneurysms, specifically feeder vessel aneurysms. Feeder vessel aneurysms are more likely to be the source of hemorrhage in the posterior fossa. As such, they may be the most appropriate targets for initial and prompt control by embolization or surgery due to their elevated threat.

Cerebrospinal Fluid Leak Presenting as Epiphora.

A 52-year-old woman underwent a right frontotemporal craniotomy for microsurgical clip obliteration of a ruptured right dorsal variant ophthalmic segment carotid aneurysm. During the craniotomy, a defect involving the orbital roof was inadvertently created. The patient was noted postoperatively to have fluid egressing from her OD. The fluid was analyzed and based on glucose and chloride levels was determined to be cerebrospinal fluid (CSF). CT scan of the head demonstrated the orbital roof defect created during surgery. After placement of a lumbar drain, fluid egress from the eye significantly decreased, further confirming the suspicion for CSF leak. Patient was found to have a conjunctival defect of the OD, approximately 2.5 cm × 1.5 cm, extending to the fornix from 9 to 12 o'clock. The conjunctival defect and fornix were repaired with an amniotic membrane graft and a temporary tarsorrhaphy with subsequent resolution of CSF egress. The case report is in compliance with the Health Insurance Portability and Accountability Act.

Clipping of a ruptured anterior communicating artery aneurysm with right A1-A2 sectioning and reanastomosis.

We showcase the microsurgical clipping of a previously coiled and ruptured anterior communicating artery aneurysm, done through a right-sided approach. Initial clipping with a fenestrated clip occluded the flow in the right A2. After temporary clipping of both A1 and A2 vessels, we cut the right A1 and A2, clipped the aneurysm with a straight clip while preserving the flow in the left A1 and A2 and then performed reanastomosis of the right A1-A2 in an end to end fashion. This strategy allowed for complete obliteration of the aneurysm while preserving the flow in all four vessels. The video can be found here: http://youtu.be/4Y024zU5NVo.

Carotid bypass for carotid occlusion.

The 2-year risk of ipsilateral ischemic stroke following internal carotid artery occlusion (ICAO) in a patient undergoing maximal medical therapy is 5-8% per year. While medical therapy may reduce the risk of stroke, it does not completely eliminate it. Since the 1985 extracranial-intracranial (EC-IC) bypass study, additional trials have been conducted to further investigate the usefulness of EC-IC bypass surgery in more selected patients with cerebral ischemia and impaired hemodynamic reserve. These important studies will be briefly reviewed in this article, as well as a discussion regarding the utility of bypass surgery for ICAO in current clinical practice. In addition, a short discussion regarding the pathophysiology of carotid occlusion will be presented. We will also highlight our own institutional patient selection criteria based on the latest methods for hemodynamic assessment, as well as our intraoperative flow assisted surgical techniques (FAST), and post-operative patient follow-up.

Clipping of bilateral MCA aneurysms and a coiled ACOM aneurysm through a modified lateral supraorbital craniotomy.

We showcase the microsurgical clipping of a left middle cerebral artery (MCA) aneurysm-(B) done through a modified right lateral supraorbital craniotomy, as well as clipping of a previously coiled anterior communicating (ACOM) artery aneurysm-(C) and a bilobed right MCA aneurysm-(A). Splitting of the right sylvian fissure is initially performed following which a subfrontal approach is used to expose and dissect the contralateral sylvian fissure. The left MCA aneurysm is identified and clipped. The ACOM aneurysm is then clipped following multiple clip repositioning based on flow measurements. The right MCA aneurysm is then identified and each lobe is clipped separately. The first picture showcased in this video is a side to side right and left ICA injection in AP projection. In this picture, (A) points to the bilobed right MCA aneurysm, (B) to the left middle cerebral artery (MCA) aneurysm, and (C) to the previously coiled anterior communicating (ACOM) artery aneurysm. The red dotted line shows that both MCA aneurysms lie within the same plane which makes it easier to clip both of them, through one small craniotomy. The video can be found here: http://youtu.be/4cQC7nHsL5I .

Extracranial aneurysms of the distal posterior inferior cerebellar artery: Resection and primary reanastomosis as the preferred management approach.

BACKGROUND: Extracranial aneurysms of the posterior inferior cerebellar artery (PICA) are rare, with only 22 reported cases in the English literature. For saccular extracranial distal PICA aneurysms not amenable to coiling, a surgically placed clip is not protected by the cranium postoperatively, and can be subject to movement in the mobile cervical region. Furthermore, fusiform or complex aneurysms cannot be clipped primarily. Resection and primary reanastomosis is a useful surgical approach not previously described for these extracranial lesions. CASE DESCRIPTION: We report three cases of extracranially located distal PICA aneurysms successfully treated with this surgical strategy at our center. One patient harboring a broad necked saccular aneurysm originally underwent successful primary clipping of the aneurysm but sustained a second subarachnoid hemorrhage (SAH) on postoperative day 25 due to clip dislodgement from vigorous neck movement. The other two patients were found to have fusiform and complex aneurysms, respectively. All three patients were ultimately treated with resection and end-to-end PICA anastomosis, which successfully obliterated their aneurysms. CONCLUSIONS: Resection and primary reanastomosis of extracranial distal PICA aneurysms averts the risk of clip dislodgement due to neck movement and/or compression by soft tissues in the upper cervical region. It is a safe and efficacious technique, which we propose as the preferred management strategy for these rare vascular lesions.

Surgical management of cervical radiculopathy caused by redundant vertebral artery loop.

In this article, the authors describe the case of a 27-year-old female presenting with a 2-year history of neck pain and radiculopathy attributable to compression of the right C-7 nerve root by tortuosity of the vertebral artery at the level of the C6-7 cervical foramina. An anterolateral approach to the transverse foramen was used to perform a vascular decompression to decompress the nerve root. The procedure was uneventful, and the patient woke up with almost all of her symptoms resolved. The authors also include a literature review of techniques performed in this setting, showing that multiple surgical approaches can be used and should be tailored to the patient symptoms and lesion characteristics.

External carotid artery stenting to treat patients with symptomatic ipsilateral internal carotid artery occlusion: a multicenter case series.

BACKGROUND: The external carotid artery (ECA) anastomoses in many distal territories supplied by the internal carotid artery (ICA) and is an important source of collateral circulation to the brain. Stenosis of the ECA in ipsilateral ICA occlusion can produce ischemic sequelae. OBJECTIVE: To examine the effectiveness of ECA stenting in treating symptomatic ipsilateral ICA occlusion. METHODS: We retrospectively reviewed patient databases from 5 academic medical centers to identify all individuals who underwent ECA stenting after 1998. For all discovered cases, coinvestigators used a common submission form to harvest relevant demographic information, clinical data, procedural details, and follow-up results for further analysis. RESULTS: Twelve patients (median age, 66 years; range, 45-79 years) were identified for our cohort. Vessel disease involvement included severe ECA stenosis >or= 70% in 11 patients and ipsilateral ICA occlusion in all patients. Presenting symptoms included signs of transient ischemic attack, stroke, and amaurosis fugax. ECA stenting was associated with preservation of neurological status in 11 patients and resolution of symptoms in 5 patients at a median follow-up time of 26 months (range, 1-87 months; mean, 29 months). Symptomatic in-stent restenosis did not occur within any patient during the follow-up course. CONCLUSION: We found ECA stenting in symptomatic ipsilateral ICA disease to be a potentially effective strategy to preserve neurological function and to relieve ischemic symptoms. Further investigation with larger studies and longer follow-up periods is warranted to elucidate the true indications of this management strategy.

Periprocedural MRI perfusion imaging to assess and monitor the hemodynamic impact of intracranial angioplasty and stenting for symptomatic atherosclerotic stenosis.

We aimed to assess the clinical value of MRI perfusion imaging in the periprocedural management of intracranial atherosclerosis, analyzing if changes in mean transit time (MTT), cerebral blood volume (CBV) and cerebral blood flow (CBF) correlated with angiographic outcomes. Pre-procedural and post-procedural MRI perfusion was performed on six patients who underwent angioplasty and/or stenting for symptomatic intracranial atherosclerosis. MTT, CBV and CBF were analyzed and graded. In 83% of patients, perfusion imaging correlated with angiographic outcomes. Perfusion parameters improved to normal in two patients. Two showed marked improvement and one showed mild improvement. In one patient, the results of the post-procedural MRI perfusion prompted an angiogram, which confirmed stent occlusion. Semi-quantitative scores of MTT and CBF changed over time (p=0.05, p=0.03) whereas CBV did not change significantly (p>0.05). We conclude that MRI perfusion appears a promising technique for analyzing the impact of intracranial stenosis on cerebral hemodynamics before and after treatment.

Genomics of human intracranial aneurysm wall.

BACKGROUND AND PURPOSE: The pathogenesis of intracranial aneurysms (IAs) remains elusive. Most studies have focused on individual genes, or a few interrelated genes or products, at a time in human IA. However, a broad view of pathologic mechanisms has not been investigated by identifying pathogenic genes and their interaction in networks. Our study aimed to analyze global gene expression patterns in the IA wall. METHODS: To our knowledge, our group was the first to perform Illumina microarray analysis on human IA via comparison of aneurysm wall and superficial temporal artery tissues from 6 consecutive patients. We adopted stringent statistical criteria to the individual genes; genes with a false discovery rate <0.01 and >2-fold change were selected as differentially expressed. To identify the overrepresented biologic pathways with the differentially expressed genes, we performed hypergeometric testing of the genes selected by relaxed criteria of P<0.01 and fold change >1.5. RESULTS: There are 326 distinct differentially expressed genes between IA and superficial temporal artery tissues (>2-fold change) with a false discovery rate <0.01. Analysis of the Kyoto Encyclopedia of Genes and Genomes pathways revealed the most impacted functional pathways: focal adhesion, extracellular matrix receptor interaction, and cell communication. Analysis of the Gene Ontology also supported the involvement of another 2 potentially important pathways: inflammatory response and apoptosis. CONCLUSIONS: The differentially expressed genes in the aneurysm wall may shed light on aneurysm pathobiology and provide novel targets for therapeutic intervention. These data will help generate hypotheses for future studies.

Endovascular embolization of a recurrent cervical giant cell neoplasm using N-butyl 2-cyanoacrylate.

Pre-operative endovascular embolization of spinal giant cell tumors (GCTs) has been an effective strategy to reduce blood loss during surgical resection. Traditionally, spinal GCTs have been embolized with polyvinyl acetate (PVA) particles. We present the pre-operative embolization of a recurrent cervical GCT with N-butyl 2-cyanoacrylate (NBCA) rather than PVA. The patient was a 17-year-old female who, 3 months prior, had undergone a surgical resection of a cervical GCT without pre-operative embolization. She returned with tumor recurrence in the approximate location. Resection was recommended, and pre-operative embolization was requested. The tumor was embolized with NBCA. Post-embolization angiography demonstrated significantly decreased tumor "blush" and a significant reduction of the vascular supply. This is the first reported use of NBCA for the pre-operative embolization of a cervical GCT. The benefits of NBCA over PVA particles include superior penetration, permanent tumor embolization and lower exposure to radiation due to shorter procedure time.

Basilar artery occlusion following C1 lateral mass fracture managed by mechanical and pharmacological thrombolysis.

BACKGROUND: Vertebral artery injury following cervical spine trauma can be associated with stroke. We present a case of a C1 fracture resulting in vertebral artery dissection and neurological decline as a result of basilar artery occlusion treated with chemical and mechanical thrombolysis resulting in basilar artery patency and clinical improvement. CASE DESCRIPTION: The patient is a 43-year-old female who was involved in a motor vehicle collision where she sustained multiple cervical spine injuries including a comminuted fracture of the left lateral mass of C1 resulting in vertebral artery dissection which eventually led to a basilar artery embolus and occlusion. A total of 15 mg of intraarterial tissue plasminogen activator was infused throughout the clot, followed by mechanical clot embolectomy using an FDA-approved device. Her neurological exam improved post-procedurally and she was discharged with a left hemiparesis to a rehabilitation facility 3 weeks after admission. At 15 month follow up, she is neurologically intact with the exception of some subtle difficulty with fine motor movement in the right upper extremity and mild dysmetria on the right. CONCLUSIONS: With this case, we report a rare and potentially devastating complication of C1 fracture. To our knowledge there are only two previously reported cases where a C1 fracture has been associated with basilar artery occlusion resulting in death and locked-in syndrome respectively. In this case, chemical thrombolysis and mechanical thrombectomy resulted in recanalization of the basilar artery with excellent long-term neurological outcome.