Demographic age-related variation in Circle of Willis completeness assessed by digital subtraction angiography.

OBJECTIVE: Incomplete circle of Willis (CoW) configuration is an important risk factor for cerebrovascular pathology, namely aneurysm formation and ischemic stroke. This study was performed to characterize CoW variation using digital subtraction angiography and to identify demographic and physiologic features that may influence the risk of having an incomplete CoW configuration. MATERIALS AND METHODS: A retrospective review of 274 patients who underwent cerebral angiography by a single surgeon for any indication was conducted. Each CoW branch was graded as normal, hypoplastic, or aplastic. Univariate and multivariate regression analyses were conducted to assess the impact of age, gender, race, and certain comorbidities on CoW configuration. RESULTS: A complete CoW was identified in 37.23% of patients. In univariate analysis, patients <40 years old were more likely to have a complete CoW (odds ratio [OR]: 4.973, 95% confidence interval [CI]: 2.610-9.476, P < 0.001) as were patients <70 years old (OR: 2.849, 95% CI: 1.131-7.194, P < 0.05). Univariate analysis on demographic factors and comorbidities revealed CoW completeness to decrease with hypertension (OR: 0.575, 95% CI: 0.347-0.951, P = 0.031) and diabetes mellitus (OR: 0.368, 95% CI: 0.180-0.754, P = 0.006). Multivariable logistic regression analysis used to assess the impact of age on CoW completeness showed age to be an independent predictor of complete CoW, with an inverse correlation between increasing age and CoW completeness (OR: 0.955, 95% CI: 0.937-0.973, P < 0.001) after controlling for potential confounders including hypertension and diabetes mellitus. CONCLUSIONS: CoW configuration shows considerable variation with age; however, further investigation is required to elucidate the full impact of other demographic and vascular risk factors on CoW anatomy.

Malignant Melanotic Schwannian Tumor Presenting with Spinal Cord Infarction Due to Occlusion of the Artery of Adamkiewicz: Case Report and Review of the Literature.

BACKGROUND: Malignant melanotic schwannian tumors (MMSTs) are rare peripheral nerve sheath tumors that typically exhibit benign clinical presentation and histopathology but malignant long-term behavior. CASE DESCRIPTION: We report a case of a 22-year-old male with a T9-11 MMST who presented with acute paraplegia and complete loss of sacral function. Despite emergent decompression, he did not recover motor, sensory or bladder function, although bowel function did normalize. CONCLUSIONS: The anatomic location and rapid presentation of permanent deficits are suggestive of infarction of the spinal cord supplied by the artery of Adamkiewicz, a rare presentation of this disorder and of spinal schwannomas in general.

The role of diffusion tensor imaging in the diagnosis, prognosis, and assessment of recovery and treatment of spinal cord injury: a systematic review.

OBJECTIVEDiffusion tensor imaging (DTI) is an MRI tool that provides an objective, noninvasive, in vivo assessment of spinal cord injury (SCI). DTI is significantly better at visualizing microstructures than standard MRI sequences. In this imaging modality, the direction and amplitude of the diffusion of water molecules inside tissues is measured, and this diffusion can be measured using a variety of parameters. As a result, the potential clinical application of DTI has been studied in several spinal cord pathologies, including SCI. The aim of this study was to describe the current state of the potential clinical utility of DTI in patients with SCI and the challenges to its use as a tool in clinical practice.METHODSA search in the PubMed database was conducted for articles relating to the use of DTI in SCI. The citations of relevant articles were also searched for additional articles.RESULTSAmong the most common DTI metrics are fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity. Changes in these metrics reflect changes in tissue integrity. Several DTI metrics and combinations thereof have demonstrated significant correlations with clinical function both in model species and in humans. Its applications encompass the full spectrum of the clinical assessment of SCI including diagnosis, prognosis, recovery, and efficacy of treatments in both the spinal cord and potentially the brain.CONCLUSIONSDTI and its metrics have great potential to become a powerful clinical tool in SCI. However, the current limitations of DTI preclude its use beyond research and into clinical practice. Further studies are needed to significantly improve and resolve these limitations as well as to determine reliable time-specific changes in multiple DTI metrics for this tool to be used accurately and reliably in the clinical setting.

Completion of the Circle of Willis Varies by Gender, Age, and Indication for Computed Tomography Angiography.

OBJECTIVE: The circle of Willis (CoW) is the foremost anastomosis and blood distribution center of the brain. Its effectiveness depends on its completion and the size and patency of its vessels. Gender-related and age-related anatomic variations in the CoW may play an important role in the pathogenesis of cerebrovascular diseases. In this study, we analyzed computed tomography angiograms (CTAs) to assess for differences in CoW completion related to gender, age, and indication for CTA. METHODS: A total of 834 CTAs were retrospectively analyzed for all CoW vessels to compare the incidence of complete CoW and variation frequency based on gender, age, and indication. RESULTS: The incidence of complete CoW was 37.1% overall. CoW completion showed a statistically significant decrease with increasing age for all age groups in both men (47.0%, 29.4%, 18.8%) and women (59.1%, 44.2%, 30.9%). Completion was greater in women (43.8%) than in men (31.2%) overall and for all age groups. These gender differences were all statistically significant except for the 18-39 years age group. The most frequent of the 28 CoW variations were absent posterior communicating artery (PCOM) bilaterally (17.1%), right PCOM (15.3%), and left PCOM (10.9%). Ischemic stroke and the 18-39 years age group of hemorrhagic stroke showed a statistically significant reduction in completion relative to trauma. CONCLUSIONS: The incidence of complete CoW is likely greater in women for all age groups and likely decreases with age in both genders. The most frequently absent vessel is likely the PCOM, either unilaterally or bilaterally. Completion may play a role in ischemic stroke and a subset of patients with hemorrhagic stroke.

Bracing After Surgical Stabilization of Thoracolumbar Fractures: A Systematic Review of Evidence, Indications, and Practices.

BACKGROUND: The role of spinal orthotic braces after surgical stabilization is not clearly defined. We systematically reviewed the published literature to determine patterns of practice, indications, and current evidence for the use of orthotic braces after surgical thoracolumbar fracture stabilization. METHODS: A search was performed for publications including descriptions of postoperative management and outcomes after surgical stabilization of thoracolumbar injuries. Differences between wearing versus not wearing a postoperative brace were examined with regard to loss of deformity correction, pain, return to previous work activity, functional improvement, instrumentation failure rate, pseudoarthrosis, and the percentage of reported complications. RESULTS: This search yielded 76 pertinent studies. Postoperative bracing (POB) was adopted in 62 studies for a median wear time of 13.3 weeks. No significant differences in terms of pain, return to work, Frankel score improvement, or instrumentation failure were found between the POB and non-POB groups. Loss of surgical kyphotic reduction was slightly greater in the POB group (4.79° vs. 3.77°; P < 0.001). The overall complication rate was also higher in the POB group (16.3% vs. 11.9%; P < 0.01). The pseudoarthrosis rate was lower in the braced group (2.4% vs. 6.0%; P < 0.001). CONCLUSIONS: Most surgeons use braces for 3 months after surgical thoracolumbar fracture stabilization. Given the lack of clinical or biomechanical evidence for this, and the additional costs and potential discomfort to patients, further investigation is warranted to determine when and if POB for surgically stabilized thoracolumbar fractures is indicated. Controlled studies should include a careful analysis of pseudoarthrosis and complication rates.

Starvation promotes concerted modulation of appetitive olfactory behavior via parallel neuromodulatory circuits.

The internal state of an organism influences its perception of attractive or aversive stimuli and thus promotes adaptive behaviors that increase its likelihood of survival. The mechanisms underlying these perceptual shifts are critical to our understanding of how neural circuits support animal cognition and behavior. Starved flies exhibit enhanced sensitivity to attractive odors and reduced sensitivity to aversive odors. Here, we show that a functional remodeling of the olfactory map is mediated by two parallel neuromodulatory systems that act in opposing directions on olfactory attraction and aversion at the level of the first synapse. Short neuropeptide F sensitizes an antennal lobe glomerulus wired for attraction, while tachykinin (DTK) suppresses activity of a glomerulus wired for aversion. Thus we show parallel neuromodulatory systems functionally reconfigure early olfactory processing to optimize detection of nutrients at the risk of ignoring potentially toxic food resources.

A paradigm for the evaluation and management of spinal coccidioidomycosis.

BACKGROUND: Coccidioidomycosis is a fungal infection that is endemic to parts of the Southwestern United States. When infection involves the spine, the treatment strategies can be challenging. We have devised a management protocol for spinal coccidioidomycosis based on a review of the literature and our experience. METHODS: The electronic literature search of National Library of Medicine for publications from 1964 to 2014 was performed using the following keywords: Coccidioidomycosis and spine. The search yielded 24 papers. Treatment strategies were summarized into a treatment protocol. RESULTS: A total of 164 cases of spinal coccidioidomycosis were identified, ranging in age from <10 to >80 years. Males (n = 131) and African-Americans (n = 79) were strikingly over-represented. Medical therapy: Once a diagnosis of spinal coccidioidomycosis is established, antifungal therapy should always be started. Antifungal therapy with amphotericin B or azoles like fluconazole. Medical therapy needs to be continued for many years and sometimes indefinitely to reduce disease recurrence or progression. Surgical management is indicated in cases with mechanical instability, neurologic deficit, medically intractable pain, or progression of infection despite antifungal therapy. CONCLUSIONS: This work provides a working protocol involving assessment and reassessment for the management of spinal coccidioidomycosis. Medical management with antifungal agents in some cases can provide satisfactory disease control. However, in patients with mechanical instability, neurologic deficit, medically intractable pain or disease progression disease control may only be achieved with surgical debridement and stabilization.

A single-fly assay for foraging behavior in Drosophila.

For many animals, hunger promotes changes in the olfactory system in a manner that facilitates the search for appropriate food sources. In this video article, we describe an automated assay to measure the effect of hunger or satiety on olfactory dependent food search behavior in the adult fruit fly Drosophila melanogaster. In a light-tight box illuminated by red light that is invisible to fruit flies, a camera linked to custom data acquisition software monitors the position of six flies simultaneously. Each fly is confined to walk in individual arenas containing a food odor at the center. The testing arenas rest on a porous floor that functions to prevent odor accumulation. Latency to locate the odor source, a metric that reflects olfactory sensitivity under different physiological states, is determined by software analysis. Here, we discuss the critical mechanics of running this behavioral paradigm and cover specific issues regarding fly loading, odor contamination, assay temperature, data quality, and statistical analysis.