Background:Spinal epidural arteriovenous fistulas (SEDAVFs) are rare lesions characterized by shunting between arterial feeders and the epidural venous plexus. Type A SEDAVFs demonstrate secondary intradural drainage and may produce congestive myelopathy resembling a spinal dural arteriovenous fistulas (SDAVFs). We report a right L3 Type A SEDAVF initially classified and treated as a SDAVF, resulting in persistent epidural shunting and recurrent symptoms. Case Description:A 73-year-old male presented with progressive gait instability, lower-extremity spasticity, and paresthesia. Conventional spinal angiography demonstrated a right L3 arteriovenous fistula with intradural perimedullary drainage, initially classified as a SDAVF. Three-dimensional rotational angiography (3DRA) was not performed initially. The patient underwent intradural coagulation and transection of the arterialized draining veins, with temporary improvement. Symptoms recurred 1 year later, and progressed over 6 months. Repeat angiography demonstrated persistent shunting with initial epidural venous plexus drainage and secondary retrograde intradural reflux, consistent with a Type A SEDAVF. 3DRA localized the fistulous point and showed no spinal cord arterial contribution from the embolized pedicle. Transarterial embolization with 33% n-butyl cyanoacrylate achieved complete occlusion. Gait, strength, and spasticity improved, with occlusion maintained at 6-month angiographic follow-up. Conclusion:Type A SEDAVFs may mimic SDAVFs when secondary intradural reflux dominates the angiographic appearance. Intradural draining vein interruption without elimination of the epidural shunt may leave persistent fistulous flow. Careful localization of the fistulous point and drainage sequence is essential, and 3DRA should be considered when conventional angiography does not clearly distinguish a dural from an epidural shunt.

Single-photon emission computed tomography/computed tomography (SPECT/CT) is an emerging imaging modality that identifies sites of heightened bone metabolism in response to increased stresses. The relationship between sacroiliac (SI) joint radiotracer uptake and anatomic biomechanical parameters is poorly understood.

Background:Esthesioneuroblastomas (ENBs) are rare malignancies of the upper digestive tract, often demonstrating local metastasis to the intracranial space through the cribriform plate. These tumors show high rates of recurrence locally following treatment. Here, we report a patient with advanced recurrent ENB 2 years following initial treatment, affecting both the spine and intracranial space without evidence of local recurrence or contiguous extension from the initial tumor site.Case Description:A 32-year-old male presents with a 2 month history of neurological symptoms 2 years following treatment of Kadish C/AJCC stage IVB (T4a, N3, M0) ENB. No evidence of locoregional recurrent disease was observed prior with intermittent imaging. Imaging revealed a large ventral epidural tumor invading multiple levels of the thoracic spine as well as a ring enhancing lesion in the right parietal lobe. The patient was treated surgically with debridement, decompression, and posterior stabilization of the thoracic spine followed by radiotherapy to the spinal and parietal lesions. Chemotherapy was also initiated. Despite treatment, the patient passed away 6 months after surgery.Conclusion:We report a case of delayed recurrent ENB with widespread metastases to the central nervous system without evidence of local disease or contiguous extension from initial tumor site. This represents a highly aggressive form of this tumor as recurrences are primarily locoregional. In follow-up of ENB treatment, clinicians must be cognizant of these tumors demonstrated ability to spread to distal regions. All new onset neurological symptoms should be investigated fully even if no local recurrence is observed.

Objective: Spinal cord sarcoidosis is a rare disorder with diverse clinical and radiographic presentations. Neurosarcoidosis may be misdiagnosed as it presents similarly to cervical spondylotic myelopathy (CSM), a more common neurosurgical pathology. Although uncommon, there is a need to distinguish these entities and identify an approach to diagnosis and treatment. A review of the current literature is provided to guide neurosurgeons receiving these patient referrals.Methods: A systematic literature review was conducted through the PubMed database with keywords "sarcoid", "cervical", and "myelopathy" to identify case reports of patients presenting with myelopathic symptoms due to neurosarcoidosis. All articles discussing patients with a presumed diagnosis of cervical spondylotic myelopathy (CSM) treated surgically with decompression but later diagnosed with neurosarcoidosis were reviewed.Results: PubMed identified 83 candidate articles, of which five met inclusion criteria. Nine total patients were reviewed. 55 % were male with a mean age of 57 & PLUSMN; 11.5 years (range 29-69 years). All patients underwent surgical decompression for a presumed diagnosis of CSM. Post-operative course led to subsequent neurologic decline within average of 1.4 & PLUSMN; 1.7 months (range 0-5 months) after surgery. Sarcoidosis was diagnosed with further testing and steroid, or immunosuppressant therapy was initiated with variable improvement.Conclusions: Although rare, neurosarcoidosis is an important differential diagnosis when considering etiologies of myelopathy and requires a high degree of suspicion. In patients with suspected findings, early diagnosis and medical treatment may prevent avoidable surgery and associated complications.

BACKGROUND: Phrenic nerve dysfunction has been associated with cervical neuroforaminal stenosis in limited case reports and case-controlled studies. It is -nclear if magnetic resonance imaging of the cervical spine should be included in the workup of patients with pulmonary dysfunction. A systematic review of the current literature was conducted on the topic to provide an outline of the body of knowledge and some guidance for neurosurgeons that receive these patient referrals.METHODS: A systematic literature review was conducted through the PubMed database to identify articles related to phrenic nerve dysfunction secondary to cervical stenosis.RESULTS: A total of 12 case reports were found. The median subject age was 64 years, 11 were male. Presenting symptoms included shortness of breath (n = 9), radiculopathy (n = 7), myelopathy (n = 5), reduced pulmonary function (n = 6), weakness (n = 4), and neck pain (n = 5). Ten of these patients underwent surgical intervention, all having improvements in their pulmonary and neuro-logical symptoms at follow-up ranging from 10 days to 2 years. -CONCLUSIONS: Cervical stenosis, resulting in neuroforaminal stenosis, may be related to phrenic nerve dysfunction in select patients with idiopathic dia-phragmatic paralysis or pulmonary dysfunction. Surgical decompression im-proves pulmonary and neurological symptoms.

•The optimal approach for stabilization of traumatic spondylolisthesis of the cervical spine is unknown.•This report presents a case where C2 pedicle lag-screws were used and reviews the supporting literature.•C2 pedicle lag-screws has been shown to be a viable option in the management of traumatic spondylolisthesis of the axis.•The supporting evidence for use of C2 pedicle lag screw placement is limited to level IV studies.

BACKGROUND:Overshunting of cerebrospinal fluid may lead to intracranial hypotension and dilation of spinal epidural veins. Radiculopathy may rarely occur secondary to engorged spinal epidural veins. In addition, the cause of radiculopathy may be obscured by concomitant spinal degenerative changes. We present a case and review the pathogenesis as well as the current clinical literature.CASE DESCRIPTION:A 29-year-old woman presented with positional headaches from intracranial hypotension in the setting of cerebrospinal fluid overshunting. The patient also had back pain and lumbar radiculopathy, which became more severe after lumboperitoneal shunt placement. On radiographic work-up, there was evidence of right L5 nerve root impingement secondary to a disc bulge and an engorged lumbar epidural venous plexus secondary to overshunting. The patient underwent surgery for a planned L4-5 decompression with a transforaminal lumbar interbody fusion. The operation was complicated by rapid blood loss originating from the epidural venous plexus, and we were unable to safely place the interbody graft.CONCLUSIONS:Spinal surgeons need to be aware of the rare diagnosis of radiculopathy secondary to epidural venous plexus engorgement, as it may change the treatment approach or lead to deleterious intraoperative consequences, such as hemorrhage.

Traditional still cameras can only focus on a single plane for each image while rendering everything outside of that plane out of focus. However, new light-field imaging technology makes it possible to adjust the focus plane after an image has already been captured. This technology allows the viewer to interactively explore an image with objects and anatomy at varying depths and clearly focus on any feature of interest by selecting that location during post-capture viewing. These images with adjustable focus can serve as valuable educational tools for neurosurgical residents. We explore the utility of light-field cameras and review their strengths and limitations compared to other conventional types of imaging. The strength of light-field images is the adjustable focus, as opposed to the fixed-focus of traditional photography and video. A light-field image also is interactive by nature, as it requires the viewer to select the plane of focus and helps with visualizing the three-dimensional anatomy of an image. Limitations include the relatively low resolution of light-field images compared to traditional photography and video. Although light-field imaging is still in its infancy, there are several potential uses for the technology to complement traditional still photography and videography in neurosurgical education.

Cortical spreading depolarization (CSD) is an electrophysiologic phenomenon found mostly in the setting of neurologic injury resulting in the disturbance of ion homeostasis and leading to changes in the local vascular response. The bioelectric etiology of CSD shares similarities to those in epileptic disorders, yet the relationship between seizures and CSD is unclear, with several studies observing cortical depression before, during, and after seizure activity, thus obscuring our understanding of whether CSD activity potentiates or limits seizures and vice versa. Cortical sampling has exhibited how the redistribution of ion concentrations in the intra- and extracellular environments interplay between the excitation of seizures and the electrical depression of CSD. Modeling of both environments has suggested that CSD synchronizes the affected tissue, creating a favorable environment for seizure activity; however, other studies have demonstrated the opposite: epileptiform activity initiating waves of CSD. Further studies have underscored the role of the vascular response and subsequent ischemia in CSD that contributes to epileptogenesis. Investigations in migraine, traumatic brain injury, and other neurologic injuries suggest that several drugs may target CSD. Manipulations in the occurrence and nature of CSD can potentially alter the threshold for seizure activity, and perhaps minimize immediate and long-term sequelae associated with epilepsy.

Cortical spreading depolarization (CSD) is a spreading loss of ion homeostasis, altered vascular response, change in synaptic architecture, and subsequent depression in electrical activity following an inciting neurological injury. First described by Leão in 1944, this disturbance in neuronal electrophysiology has since been demonstrated in a number of animal studies, and recently a few human studies that examine the occurrence of this depolarizing phenomenon in the setting of a variety of pathological states, including migraines, cerebrovascular accidents, epilepsy, intracranial hemorrhages, and traumatic brain injuries. The onset of CSD has been demonstrated experimentally following a disruption in the neuronal environment leading to glutamate-induced toxicity. This initial event leads to pathological changes in the activity of ion channels that maintain membrane potential. Recovery mechanisms such as sodium-potassium pumps that aim to restore homeostasis fail, leading to osmolar shifts of fluid, swelling of the neuron, and ultimately a measurable depression in cortical activity that spreads in the order of millimeters per minute. Equally important is the resulting change in vascular response. In healthy tissue, increased electrical activity is coupled with release of vasodilatory factors such as nitric oxide and arachidonic acid metabolites that increase local blood flow to meet increased energy expenditure. In damaged tissue, not only is the restorative vascular response lacking but a vasoconstrictive response is promoted and the ischemia that follows adds to the severity of the initial injury. Tissue threatened by this ischemic response is then at elevated risk for CSD propagation and falls into a vicious cycle of electrical and hemodynamic disturbance. Efforts have been made to halt this spreading cortical depression using N-methyl-D-aspartate receptor antagonists and other ion channel blockers to minimize the damaging effects of CSD that can persist long after the triggering insult.

Cadaveric surgical simulation carries the advantage of realistic anatomy and haptic feedback but has been historically difficult to model for intraventricular approaches given the need for active flow of CSF. This feasibility study was designed to simulate intraventricular neuroendoscopic approaches and techniques by reconstituting natural CSF flow in a cadaveric model. In 10 fresh human cadavers, a simple cervical laminectomy and dural opening were made, and a 12-gauge arterial catheter was introduced. Saline was continuously perfused at physiological CSF pressures to reconstitute the subarachnoid space and ventricles. A neuroendoscope was subsequently inserted via a standard right frontal bur hole. In 8 of the 10 cadavers, adequate reconstitution and endoscopic access of the lateral and third ventricles were achieved. In 2 cadavers, ventricular access was not feasible, perhaps because of a small ventricle size and/or deteriorated tissue quality. In all 8 cadavers with successful CSF flow reconstitution and endoscopic access, identifying the foramen of Monro was possible, as was performing septum pellucidotomy and endoscopic third ventriculostomy. Furthermore, navigation of the cerebral aqueduct, fourth ventricle, prepontine cistern, and suprasellar cistern via the lamina terminalis was possible, providing a complementary educational paradigm for resident education that cannot typically be performed in live surgery. Surgical simulation plays a critical and increasingly prominent role in surgical education, particularly for techniques with steep learning curves including intraventricular neuroendoscopic procedures. This novel model provides feasible and realistic surgical simulation of neuroendoscopic intraventricular procedures and approaches.

Biomedical signal and image processing establish a dynamic area of specialization in both academic as well as research aspects of biomedical engineering. The concepts of signal and image processing have been widely used for extracting the physiological information in implementing many clinical procedures for sophisticated medical practices and applications. In this paper, the relationship between electrophysiological signals, i.e., electrocardiogram (ECG), electromyogram (EMG), electroencephalogram (EEG) and functional image processing and their derived interactions have been discussed. Examples have been investigated in various case studies such as neurosciences, functional imaging, and cardiovascular system, by using different algorithms and methods. The interaction between the extracted information obtained from multiple signals and modalities seems to be very promising. The advanced algorithms and methods in the area of information retrieval based on time-frequency representation have been investigated. Finally, some examples of algorithms have been discussed in which the electrophysiological signals and functional images have been properly extracted and have a significant impact on various biomedical applications.