Small Vestibular Schwannomas: Does Surgery Remain a Viable Treatment Option?

Background Surgery for small vestibular schwannomas (Koos grade I and II) has been increasingly rejected as the optimal primary treatment, instead favoring radiosurgery and observation that offer lower morbidity and potentially equal efficacy. Our study assesses the outcomes of contemporary surgical strategies including tumor control, functional preservation, and implications of pathologic findings. Design Retrospective review.

Inter-site and inter-scanner diffusion MRI data harmonization.

We propose a novel method to harmonize diffusion MRI data acquired from multiple sites and scanners, which is imperative for joint analysis of the data to significantly increase sample size and statistical power of neuroimaging studies. Our method incorporates the following main novelties: i) we take into account the scanner-dependent spatial variability of the diffusion signal in different parts of the brain; ii) our method is independent of compartmental modeling of diffusion (e.g.

Development and application of a microfabricated multimodal neural catheter for neuroscience.

We present a microfabricated neural catheter for real-time continuous monitoring of multiple physiological, biochemical and electrophysiological variables that are critical to the diagnosis and treatment of evolving brain injury. The first generation neural catheter was realized by polyimide-based micromachining and a spiral rolling packaging method. The mechanical design and electrical operation of the microsensors were optimized and tailored for multimodal monitoring in rat brain such that the potential thermal, chemical and electrical crosstalk among the microsensors as well as errors from micro-environmental fluctuations are minimized.

Cochlear implantation after radiation therapy for acoustic neuroma.

Neurofibromatosis type 2 (NF-2) represents the complex issue of hearing restoration after treatment for a patient with bilateral acoustic neuromas. This scenario is difficult for skull base teams considering that all treatment options (including observation of tumors) pose a risk to the patient for further or total hearing loss. In this case of a patient with bilateral deafness, restoration options were auditory brainstem or cochlear implantation (CI).

Excitotoxicity and Metabolic Crisis Are Associated with Spreading Depolarizations in Severe Traumatic Brain Injury Patients.

Cerebral microdialysis has enabled the clinical characterization of excitotoxicity (glutamate >10 μM) and non-ischemic metabolic crisis (lactate/pyruvate ratio [LPR] >40) as important components of secondary damage in severe traumatic brain injury (TBI). Spreading depolarizations (SD) are pathological waves that occur in many patients in the days following TBI and, in animal models, cause elevations in extracellular glutamate, increased anaerobic metabolism, and energy substrate depletion. Here, we examined the association of SD with changes in cerebral neurochemistry by placing a microdialysis probe alongside a subdural electrode strip in peri-lesional cortex of 16 TBI patients requiring neurosurgery.

Final infarct volume discriminates outcome in mild strokes.

Introduction: Knowledge of whether final infarct volume (FIV) predicts disability after mild stroke is limited. We sought to determine if FIV could differentiate good versus poor outcome after mild stroke.

Methods: We retrospectively identified 65 patients with mild stroke (National Institutes of Health Stroke Scale≤5) in a multicenter registry of 2453 patients.

Single probe for real-time simultaneous monitoring of neurochemistry and direct-current electrocorticography.

We report a novel single neural probe for real-time simultaneous monitoring of multiple neurochemicals and direct-current electrocorticography (DC-ECoG). A major advance of this probe is the inclusion of two iridium oxide reference electrodes to improve sensor accuracy. The ECoG reference electrode is identical to the ECoG recording electrodes to significantly improve DC stability, while the reference for electrochemical sensors has 10-fold lower polarization rate to minimize the small current-induced drift in the reference electrode potential.

Improving access and timeliness of care for veterans with head and neck squamous cell carcinoma: A multidisciplinary team's approach.

Objectives/hypothesis: With the prevalence of head and neck squamous cell carcinoma (HNSCC) nearly twice as high in veterans (6%) than general populations (3%), the noted problems of long waits and access to care in United States Veterans Affairs (VA) hospitals across the country are pressing. We examined primary outcome measures of timeliness and access to care for our patients with HNSCC assessing a multidisciplinary team approach at our VA hospital.

Study Design: Retrospective chart review.

Real-time monitoring of extracellular adenosine using enzyme-linked microelectrode arrays.

Throughout the central nervous system extracellular adenosine serves important neuroprotective and neuromodulatory functions. However, current understanding of the in vivo regulation and effects of adenosine is limited by the spatial and temporal resolution of available measurement techniques. Here, we describe an enzyme-linked microelectrode array (MEA) with high spatial (7500 µm(2)) and temporal (4 Hz) resolution that can selectively measure extracellular adenosine through the use of self-referenced coating scheme that accounts for interfering substances and the enzymatic breakdown products of adenosine.

Monocyte Count and 30-Day Case Fatality in Intracerebral Hemorrhage.

Background And Purpose: Monocytes may contribute to secondary injury after intracerebral hemorrhage (ICH). We tested the association of absolute monocyte count with 30-day ICH case fatality in a multiethnic cohort.

Methods: Ethnic/Racial Variations of Intracerebral Hemorrhage (ERICH) study is a prospective, multicenter, case-control study of ICH among white, black, and Hispanic patients.

Assessment of Cerebrovascular Autoregulation Using Regional Cerebral Blood Flow in Surgically Managed Brain Trauma Patients.

Background: Impairment of cerebrovascular autoregulation is a risk factor for ischemic damage following severe brain injury. Autoregulation can be assessed indirectly using intracranial pressure monitoring as a surrogate of cerebral blood volume, but this measure may not be applicable to patients following decompressive craniectomy. Here, we describe assessment of autoregulation using regional cerebral blood flow (rCBF).

The extended transorbital craniotomy: an anatomic study.

Background: Supra-/transorbital approaches are mostly limited to suprasellar and anterior fossa pathologies, whereas lateral supraorbital approaches provide less retrosellar exposure and less overall operative volume, especially in the temporal region.

Objective: Our cadaveric study proposes removal of the lesser and greater wings of the sphenoid bone to increase both the lateral angle typically achieved with pterional approaches and exposure to the temporal lobe and perisellar region.

Methods: In 5 cadaveric specimens, our 3 steps to expand transorbital exposures included the following: step 1, standard transorbital craniotomy via a 3-cm supra-eyebrow incision; step 2, removal of the lesser sphenoid wing completed extradurally; and step 3, partial removal of the greater sphenoid wing.

Spreading depolarizations mediate excitotoxicity in the development of acute cortical lesions.

Spreading depolarizations (SD) are mass depolarizations of neurons and astrocytes that occur spontaneously in acute brain injury and mediate time-dependent lesion growth. Glutamate excitotoxicity has also been extensively studied as a mechanism of neuronal injury, although its relevance to in vivo pathology remains unclear. Here we hypothesized that excitotoxicity in acute lesion development occurs only as a consequence of SD.

Comparing operative exposures of the le fort I osteotomy and the expanded endoscopic endonasal approach to the clivus.

Objectives We compare surgical exposures to the clivus by Le Fort I osteotomy (LFO) and the expanded endoscopic endonasal approach (EEEA). Methods Ten cadaveric specimens were imaged with 1.25-mm computed tomography.

Vestibular schwannoma or tanycytic ependymoma: Immunohistologic staining reveals.

Background: The cerebellopontine angle (CPA) is a common location for primary tumors, most often vestibular schwannomas, and also meningiomas, dermoids, and a host of other neoplasms. Our case report illustrates how radiologic and histopathologic presentations of an unusual variant of ependymal neoplasm can be diagnostically challenging and how accurate diagnosis can affect treatment protocols.

Case History: Our patient had a CPA mass that was a variant of ependymoma known as tanycytic ependymoma that mimicked vestibular schwannoma radiologically and during intraoperative pathologic examination.

Segments of the internal carotid artery during endoscopic transnasal and open cranial approaches: can a uniform nomenclature apply to both?

Background: The classic anatomic view of the course of the internal carotid artery (ICA) and its segments familiar to neurosurgeons by a 3-dimensional microscopic cranial view may be challenging to understand when seen in the unique 2-dimensional view of transnasal endoscopic surgery.

Objective: We re-examined our 1996 classification of 7 (C1-C7) segments of the ICA, comparing the arterial course in cadaveric dissections for both a transnasal endoscopic transpenoidal approach and frontotemporal craniotomy.

Methods: Five formalin-fixed cadaveric heads injected with colored silicone underwent thin-cut computed tomographic scanning for bony and vascular analysis.

Facial nerve preservation surgery for koos grade 3 and 4 vestibular schwannomas.

Background: Facial nerve preservation surgery for large vestibular schwannomas is a novel strategy for maintaining normal nerve function by allowing residual tumor adherent to this nerve or root-entry zone.

Objective: To report, in a retrospective study, outcomes for large Koos grade 3 and 4 vestibular schwannomas.

Methods: After surgical treatment for vestibular schwannomas in 52 patients (2004-2013), outcomes included extent of resection, postoperative hearing, and facial nerve function.

Inverse neurovascular coupling to cortical spreading depolarizations in severe brain trauma.

Cortical spreading depolarization causes a breakdown of electrochemical gradients following acute brain injury, and also elicits dynamic changes in regional cerebral blood flow that range from physiological neurovascular coupling (hyperaemia) to pathological inverse coupling (hypoperfusion). In this study, we determined whether pathological inverse neurovascular coupling occurred as a mechanism of secondary brain injury in 24 patients who underwent craniotomy for severe traumatic brain injury. After surgery, spreading depolarizations were monitored with subdural electrode strips and regional cerebral blood flow was measured with a parenchymal thermal diffusion probe.

Short-Term Quality-of-Life Changes after Endoscopic Pituitary Surgery Rated with SNOT-22.

Objective Little data exist on short-term quality-of-life (QOL) outcomes, specifically sinonasal measures, after endoscopic pituitary surgery. Design Prospective case series assessed sinonasal QOL before and after the transnasal endoscopic approach to the sella with resection of nasal cavity and sinus tissues. Setting/Participants/Main Outcome Measures A total of 39 adults scheduled to undergo resection for a pituitary mass preoperatively completed the Sinonasal Outcome Test-22 (SNOT-22).

Refining the Indications for the Addition of Orbital Osteotomy during Anterior Cranial Base Approaches: Morphometric and Radiologic Study of the Anterior Cranial Base Osteology.

Objectives In anatomic and radiologic morphometric studies, we examine a predictive method, based on preoperative imaging of the anterior cranial base, to define when addition of orbital osteotomy is warranted. Design Anatomic and radiographic study. Setting In 100 dry skulls, measurements in the anterior cranial fossa included three lines and two angles based on computerized tomography (CT) scans taken in situ and validated using frameless stereotactic navigation.

Onyx HD-500 embolization of intracranial aneurysms: modified technique using continuous balloon inflation under conscious sedation.

The conventional technique of intracranial aneurysm embolization using Onyx HD-500 (ev3 Neurovascular, Irvine, CA, USA) involves repetitive balloon inflation-deflation cycles under general anesthesia. By limiting parent artery occlusion to 5 minutes, this cyclic technique is thought to minimize cerebral ischemia. However, intermittent balloon deflation may lengthen procedure time and allow balloon migration, resulting in intimal injury or Onyx leakage.

Predicting parent vessel patency and treatment durability: a proposed grading scheme for the immediate angiographic results following Onyx HD-500 embolization of intracranial aneurysms.

Introduction: Onyx HD-500 embolization of intracranial aneurysms leads to high rates of complete and durable occlusion. However, little information exists as to what constitutes an optimal immediate angiographic result. We devised a simple grading scheme based on the pattern of parent artery and aneurysm neck reconstruction, and correlated it with long term outcome.

Anatomic variation of the optic strut: classification schema, radiologic evaluation, and surgical relevance.

Objective Anatomic variability of the optic strut in location, orientation, and dimensions is relevant in approaching ophthalmic artery aneurysms and tumors of the anterior cavernous sinus, medial sphenoid wing, and optic canal. Methods In 84 dry human skulls, imaging studies were performed (64-slice computed tomography [CT] scanner, axial view, aligned with the zygomatic arch). Optic strut location related to the prechiasmatic sulcus was classified as presulcal, sulcal, postsulcal, and asymmetric.