Decompressive hemicraniectomy after malignant middle cerebral artery infarction: rationale and controversies.

Malignant middle cerebral artery stroke carries a very poor prognosis. Significant retrospective data support the hypothesis that decompressive hemicraniectomy decreases mortality rates due to this disease entity. Recently, 3 randomized controlled studies have been published and shed light on these issues and enhance the quality of evidence revolving around this procedure. In this review, the rationale, risks, benefits, and unanswered questions related to hemicraniectomy for acute ischemic stroke are reviewed with an emphasis on how 3 randomized trials have influenced knowledge on this life-saving yet controversial procedure. Further randomized studies are needed to clarify lingering questions regarding age indications and impact on quality of life.

Moyamoya disease: a review of histopathology, biochemistry, and genetics.

OBJECT: Moyamoya disease (MMD) is a rare cerebrovascular disorder involving stenosis of the major vessels of the circle of Willis and proximal portions of its principal branches. Despite concerted investigation, the pathophysiology of the disorder has not been fully elucidated. Currently, the major proteins believed to play an active role in the pathogenesis include vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), transforming growth factor-ß1 (TGFß1), and granulocyte colony-stimulating factor (G-CSF). In terms of the genetics, recent literature suggests a low penetrance autosomal dominant or polygenic mode of transmission involving chromosomes 3, 6, 8, 12, and 17 for familial MMD. This review summarizes the current knowledge on the histopathology, pathophysiology and genetics of MMD. METHODS: A PubMed/Medline systematic study of the literature was performed, from which 45 articles regarding MMD pathophysiology were identified and analyzed. CONCLUSIONS: Moyamoya disease is characterized by the intimal thickening and media attenuation of the proximal vessels of the circle of Willis as well as the development of an aberrant distal vascular network. The primary proteins that are currently implicated in the pathophysiology of MMD include VEGF, bFGF, HGF, TGFß1, and G-CSF. Furthermore, the current literature on familial MMD has pointed to a low penetrance autosomal dominant or polygenic mode of transmittance at loci on chromosomes 3, 6, 8, 12, and 17.

Posterior fossa arteriovenous malformations.

Arteriovenous malformations (AVMs) of the posterior fossa are complex neurovascular lesions that are less common than their supratentorial counterparts, accounting for < 15% of all AVMs. The majority of patients with these lesions present with intracranial hemorrhage, a factor that has been consistently shown to increase one's risk for subsequent bleeding. Studies have additionally shown a posterior fossa or deep AVM location to portend a more aggressive natural history. The authors reviewed the literature on posterior fossa AVMs, finding their annual rupture rates to be as high as 11.6%, an important factor that underscores the importance of aggressive treatment of lesions amenable to intervention as therapeutic options and results continue to improve.

A computer vision approach to identifying the manufacturer and model of anterior cervical spinal hardware.

OBJECTIVE: Recent advances in computer vision have revolutionized many aspects of society but have yet to find significant penetrance in neurosurgery. One proposed use for this technology is to aid in the identification of implanted spinal hardware. In revision operations, knowing the manufacturer and model of previously implanted fusion systems upfront can facilitate a faster and safer procedure, but this information is frequently unavailable or incomplete. The authors present one approach for the automated, high-accuracy classification of anterior cervical hardware fusion systems using computer vision. METHODS: Patient records were searched for those who underwent anterior-posterior (AP) cervical radiography following anterior cervical discectomy and fusion (ACDF) at the authors' institution over a 10-year period (2008-2018). These images were then cropped and windowed to include just the cervical plating system. Images were then labeled with the appropriate manufacturer and system according to the operative record. A computer vision classifier was then constructed using the bag-of-visual-words technique and KAZE feature detection. Accuracy and validity were tested using an 80%/20% training/testing pseudorandom split over 100 iterations. RESULTS: A total of 321 total images were isolated containing 9 different ACDF systems from 5 different companies. The correct system was identified as the top choice in 91.5% ± 3.8% of the cases and one of the top 2 or 3 choices in 97.1% ± 2.0% and 98.4 ± 13% of the cases, respectively. Performance persisted despite the inclusion of variable sizes of hardware (i.e., 1-level, 2-level, and 3-level plates). Stratification by the size of hardware did not improve performance. CONCLUSIONS: A computer vision algorithm was trained to classify at least 9 different types of anterior cervical fusion systems using relatively sparse data sets and was demonstrated to perform with high accuracy. This represents one of many potential clinical applications of machine learning and computer vision in neurosurgical practice.

Presentation, Treatment, and Long-Term Outcome of Intrasellar Chordoma: A Pooled Analysis of Institutional, SEER (Surveillance Epidemiology and End Results), and Published Data.

BACKGROUND: Chordoma that occurs primarily in the sella turcica is rare and presents unique treatment challenges. OBJECTIVE: The purpose of this study was to determine common features, treatment approaches, and survival characteristics of intrasellar chordoma. METHODS: Institutional databases, the SEER (Surveillance Epidemiology and End Results) database, and PubMed/EMBASE were queried for chordoma with a primarily intrasellar component. The SEER database was also queried for adult skull base chordoma. Patient-level data were extracted where available. Kaplan-Meier survival analyses were conducted. RESULTS: Among 80 cases, the mean age at presentation was 55.6 (standard deviation, 15.9), with a female predominance (1.16:1.00). Patients experienced symptoms for a mean duration of 19.0 months, including cranial nerve deficits, hypopituitarism, and hyperprolactinemia. Among patients receiving treatment, 77.5% underwent surgery. In addition, less than half of the patients (n = 34, 47.3%) received adjuvant radiation therapy. The 5-year overall survival (OS) of intrasellar chordoma was 60.0% (standard error [SE], 6.9). Patients aged 40 years and younger had a 5-year OS of 80.8% (SE, 12.2), compared with patients older than 40 years, who had an OS of 55.4% (SE, 7.7) (Mantel-Cox, P = 0.044). Males experienced a lower 5-year OS (44.0; SE, 9.7) than did females (76.8; SE, 8.5), (Mantel-Cox, P = 0.003). Median OS was greater in patients with skull base chordoma than in patients with intrasellar chordoma (Mantel-Cox, P = 0.046). CONCLUSIONS: Intrasellar chordoma presents frequently with visual disturbances and hyperprolactinemia and has a slightly higher incidence in females. Young age predicts a better prognosis. Intrasellar chordoma has a lower overall survival than has skull base chordoma.

Endoscopic Approach to Clival Chordomas: The Northwestern Experience.

INTRODUCTION: Chordomas are rare primary bone tumors with a low-grade histology but an aggressive clinical behavior characterized by local invasion and recurrence. When occurring in the skull base, their treatment is limited by proximity to critical neurovascular structures. Open surgical approaches can carry high morbidity, making the development of alternative approaches desirable. We describe our experience with endoscopic endonasal approaches to clival chordomas over 13 years. METHODS: We performed a retrospective chart review of patients diagnosed with clival chordomas and treated with an endoscopic endonasal approach between 2003 and 2015 at Northwestern Memorial Hospital. We reviewed presenting symptoms, tumor location and size, extent of resection, complications, recurrence, adjuvant treatment, retreatment, and follow-up duration. RESULTS: A total of 23 charts were reviewed, with 17 included in our final review. Mean age was approximately 48 years. The most common presenting symptom was diplopia present in 70.6% of patients. Mean tumor volume was 20.2 cm3. Gross total resection was achieved in 52.9% of patients. With a mean follow-up period of 63.4 months, 5 patients had a recurrence. The most common complication was cerebrospinal fluid (CSF) leak, which was noted in 6 patients. Tumor volume was significantly higher in patients with CSF leak. No correlation between intradural extension and postoperative CSF leak was noted. CONCLUSIONS: Clival chordoma are challenging entities to treat. The best outcomes are achieved with gross total resection followed by adjuvant radiotherapy treatment. We show that the endonasal endoscopic corridor is a viable alternative approach to these lesions.

Microsurgical Treatment of Previously Coiled Intracranial Aneurysms: Systematic Review of the Literature.

OBJECTIVE: To assess indications, complications, clinical outcomes, and technical nuances of microsurgical treatment of previously coiled intracranial aneurysms. METHODS: A systematic review of the literature was performed using PubMed/MEDLINE and EMBASE databases from January 1990 to December 2013. English-language articles reporting on microsurgical treatment of previously coiled intracranial aneurysms were included. Articles that involved embolization materials other than coils were excluded. Data on aneurysm characteristics, indications for surgery, techniques, complications, angiographic obliteration rates, and clinical outcomes were collected. RESULTS: The literature review identified 29 articles reporting on microsurgical clipping of 375 previously coiled aneurysms. Of the aneurysms, 68% were small (<10 mm). Indications for clipping included the presence of a neck remnant (48%) and new aneurysmal growth (45%). Rebleeding before clipping was reported in 6% of cases. Coil extraction was performed in 13% of cases. The median time from initial coiling to clipping was 7 months. The angiographic cure rate was 93%, with morbidity and mortality of 9.8% and 3.6%, respectively. CONCLUSIONS: Microsurgical clipping of previously coiled aneurysms can result in high obliteration rates with relatively low morbidity and mortality in select cases. Considerations for microsurgical strategies include the presence of sufficient aneurysmal tissue for clip placement and the potential need for temporary occlusion or flow arrest. Coil extraction is not needed in most cases.

Survival after surgery and stereotactic radiosurgery for patients with multiple intracranial metastases: results of a single-center retrospective study.

OBJECTIVES: Patients with systemic cancer and a single brain metastasis who undergo treatment with resection plus radiotherapy live longer and have a better quality of life than those treated with radiotherapy alone. Historically, whole-brain radiotherapy (WBRT) has been the mainstay of radiation therapy; however, it is associated with significant delayed neurocognitive sequelae. In this study, the authors looked at survival in patients with single and multiple intracranial metastases who had undergone surgery and adjuvant stereotactic radiosurgery (SRS) to the tumor bed and synchronous lesions. METHODS: The authors retrospectively reviewed the records from an 8-year period at a single institution for consecutive patients with brain metastases treated via complete resection of dominant lesions and adjuvant radiosurgery. The cohort was analyzed for time to local progression, synchronous lesion progression, new intracranial lesion development, systemic progression, and overall survival. The Kaplan-Meier method (stratified by age, sex, tumor histology, and number of intracranial lesions prior to surgery) was used to calculate both progression-free and overall survival. A Cox proportional-hazards regression model was also fitted with the number of intracranial lesions as the predictor and survival as the outcome controlling for disease severity, age, sex, and primary histology. RESULTS: The median overall follow-up among the 150-person cohort eligible for analysis was 17 months. Patients had an average age of 46.2 years (range 16-82 years), and 62.7% were female. The mean (± standard deviation) number of intracranial lesions per patient was 2.5 ± 2.3. The mean time between surgery and stereotactic radiosurgery (SRS) was 3.2 ± 4.1 weeks. Primary cancers included lung cancer (43.3%), breast cancer (21.3%), melanoma (10.0%), renal cell carcinoma (6.7%), and colon cancer (6.7%). The average number of isocenters per treated lesion was 7.6 ± 6.6, and the average treatment dose was 17.8 ± 2.8 Gy. One-year survival for patients in this cohort was 52%, and the 1-year local control rate was 77%. The median (±standard error) overall survival was 13.2 ± 1.9 months. There was no difference in survival between patients with a single lesion and those with multiple lesions (p = 0.319) after controlling for age, sex, and histology of primary tumor. Patients with primary breast histology had the greatest overall median survival (22.9 ± 6.2 months); patients with colorectal cancer had the shortest overall median survival (5.3 ± 1.8 months). The most common cause of death in this series was systemic progression (79%). CONCLUSIONS: These results confirm that 1-year survival for patients with multiple intracranial metastases treated with resection followed by SRS to both the tumor bed and synchronous lesions is similar to established outcomes for patients with a single intracranial metastasis.

De novo large fusiform posterior circulation intracranial aneurysm presenting with subarachnoid hemorrhage 7 years after therapeutic internal carotid artery occlusion: case report and review of the literature.

BACKGROUND AND IMPORTANCE: Although the use of proximal artery occlusion, or hunterian ligation, for the treatment of intracranial aneurysms has decreased greatly over the past decades, this approach still finds use for certain giant and complex aneurysms. The main risks of artery sacrifice are ischemic complications but also, although rare, de novo aneurysm formation. We present here a case of de novo formation of a large fusiform basilar artery aneurysm 7 years after internal carotid artery occlusion. CLINICAL PRESENTATION: A 17-year-old male patient with a history of a giant right cavernous aneurysm treated 7 years earlier with right-sided endovascular internal carotid artery occlusion presented to our institution with a thunderclap headache. At the time of initial evaluation, the patient was neurologically intact and imaging revealed a 22 × 10-mm fusiform aneurysm of the distal basilar artery with mass effect on the adjacent pons as well as a small amount of subarachnoid and intraventricular blood. Complete occlusion of the right internal carotid artery was demonstrated with retrograde filling of the right middle cerebral artery from the enlarged right posterior communicating artery. The patient was subsequently treated with hunterian occlusion of the basilar artery below anterior inferior cerebellar arteries. A superficial temporal artery to middle cerebral artery bypass was performed on the right side before this occlusion. CONCLUSION: Further studies on the epidemiology of de novo aneurysms after carotid artery occlusion are warranted. Patients at higher risk of the development of intracranial aneurysms should be followed aggressively after hunterian ligation, and the possibility of an extracranial-intracranial bypass should be discussed.

Past, present, and future perspectives on the endovascular treatment of acute ischemic stroke.

Interventional neuroradiology plays a continuously expanding and exciting role in the treatment of acute stroke, as evidenced by the development of several important advances, including the advent of multiple new devices and therapies. Furthermore, guidelines regarding endovascular interventions in the setting of acute stroke have been developed and used. In addition to technological advances, the field of pharmacology in the setting of acute stroke is constantly evolving. In a rapidly expanding field, we aim to review significant recent advances related to the endovascular treatment of stroke as well as provide perspective for future directions.