Search

One of the defining narratives of the COVID-19 pandemic has been the acceptance and distribution of vaccine.Compare the outcomes of COVID-19 positive vaccinated and unvaccinated stroke patients.This is a single-center retrospective study of COVID-19-vaccinated and unvaccinated stroke patients between April 2020 and March 2022. All patients presenting with stroke regardless of treatment modalities were included. NIHSS was used to assess stroke severity. The primary outcome was functional capacity of the patients at discharge.The study cohort comprised 203 COVID-19 positive stroke patients divided into 139 unvaccinated and 64 fully vaccinated patients. At discharge, the mRS score was significantly lower in the vaccinated cohort (3[1-4] vs 4[2-5], OR=0.508, p=0.011). At 3 months of follow-up, the median mRS score was comparable between both cohorts.Although vaccination did not show any significant difference in stroke patient outcomes on follow-up, vaccines were associated with lower rates of morbidity and mortality at discharge among stroke patients during the pandemic.

OBJECTIVE Stent-assisted coil (SAC) embolization has been the mainstay endovascular treatment for bifurcation aneurysms. The recent introduction of the Woven EndoBridge (WEB) device has presented an alternative endovascular treatment modality for these aneurysms. Direct comparisons of outcomes between these two modalities are limited in the literature. Here, the authors compared the outcomes of bifurcation aneurysms treated with SAC and WEB devices. METHODS This retrospective single-center study comprised 148 bifurcation aneurysms that were treated endovascularly with SAC or WEB devices between 2011 and 2019. The primary outcome was complete occlusion of the aneurysm at 6 months on catheter angiography. RESULTS The SAC and WEB cohorts comprised 85 and 63 aneurysms, respectively. The baseline characteristics were well balanced after inverse probability weight (IPW) adjustment, except for smoking status. The 6-month complete occlusion rate was higher in the WEB cohort than the SAC cohort (67.4% vs 40.6%; unadjusted OR [95% CI] 3.014 [1.385–6.563], p = 0.005). However, this difference in complete occlusion rates did not remain significant after IPW adjustment and multiple imputations. The neck remnant rate was lower in the WEB cohort than the SAC cohort (20% vs 50%; OR [95% CI] 0.250 [0.107–0.584], p = 0.001), and this difference remained significant after IPW adjustment (OR [95% CI] 0.304 [0.116–0.795], p = 0.015) and multiple imputations. CONCLUSIONS Use of SAC and WEB demonstrated comparable 6-month complete occlusion rates for bifurcation aneurysms. WEB appeared to be associated with a lower rate of neck remnant at 6 and 12 months compared with SAC. WEB was also associated with fewer complications and decreased retreatment rates compared with SAC.

Traditional Gamma Knife radiosurgery (GKRS) of brain arteriovenous malformations (AVMs) using digital subtraction angiography (DSA) requires head immobilization using a stereotactic frame.We describe our protocol of frameless GKRS using DSA while maintaining high spatial resolution for precision.This study is a retrospective review of patients with unruptured AVMs who underwent frameless GKRS. Magnetic resonance imaging and 3-dimensional DSA were obtained without a stereotactic frame for all patients. The imaging studies were merged for contouring of the AVM nidus. During GKRS treatment, patients were immobilized using an individually molded thermoplastic mask.Thirty-one patients were included in the analysis. The median age is 45.0 years (interquartile range [IQR]: 28.0-55.0). The median nidus size is 3.0 cm (IQR: 2.0-3.4). One patient had a Spetzler-Martin grade I, 11 had a grade II, 11 had a grade III, 6 had a grade IV, and 2 had a grade V AVM. Eleven patients underwent preradiosurgical embolization, 3 patients had previous microsurgical resection and/or embolization, and 1 patient had prior radiosurgery. The median administered dose was 20 Gy (IQR: 18.0-21.0). All patients completed their treatment with the planned radiation dose without complications.This is the first study that integrates DSA in the treatment planning of brain AVMs using GKRS without utilizing a stereotactic head frame. Frameless GKRS provides numerous advantages over frame-based techniques including improved patient experience and the capability of fractionation and thus expanding the eligibility of more AVMs for radiosurgery, while maintaining high spatial resolution of the AVM using angiography data.

Background The transradial access (TRA) is rapidly gaining popularity for neuroendovascular procedures as there is strong evidence for its benefits compared to the traditional transfemoral access (TFA). However, the transition to TRA bears some challenges including optimization of the interventional suite set-up and workflow as well as its impact on fellowship training. Objective To compare the learning curves of TFA and TRA for diagnostic cerebral angiograms in neuroendovascular fellowship training. Methods We prospectively collected diagnostic angiogram procedural data on the performance of 2 neuroendovascular fellows with no prior endovascular experience who trained at our institution from July 2018 until June 2019. Metrics for operator proficiency were minutes of fluoroscopy time, procedure time, and volume of contrast used. Results A total of 293 diagnostic angiograms were included in the analysis. Of those, 57.7% were TRA and 42.3% were TFA. The median contrast dose was 60 cc, and the median radiation dose was 14 000 μGy. The overall complication rate was 1.4% consisting of 2 groin hematomas, 1 wrist hematoma, and 1 access-site infection using TFA. The crossover rate to TFA was 2.1%. Proficiency was achieved after 60 femoral and 95 radial cases based on fluoroscopy time, 52 femoral and 77 radial cases based on procedure time, and 53 femoral and 64 radial cases based on contrast volume. Conclusion Our study demonstrates that the use of TRA can be safely incorporated into neuroendovascular training without causing an increase in complications or significantly prolonging procedure time or contrast use.

The use of flow diverters for treating intracranial aneurysms has been widely used in the past decade; however, data comparing pipeline embolization device (PED; Medtronic Inc) and flow-redirection endoluminal device (FRED; MicroVention) in the treatment of intracranial aneurysms remain scarce.To compare the outcomes of PED and FRED in the treatment of intracranial aneurysms.This is a single-center retrospective review of aneurysms treated with PED and FRED devices. Patients treated with PED or FRED were included. Cases requiring multiple or adjunctive devices were excluded. Primary outcome was complete aneurysm occlusion at 6 months. Secondary outcomes included good functional outcome, need for retreatment, and any complication.The study cohort comprised 150 patients, including 35 aneurysms treated with FRED and 115 treated with PED. Aneurysm characteristics including location and size were comparable between the 2 cohorts. 6-month complete occlusion rate was significantly higher in the PED cohort (74.7% vs 51.5%; P = .017) but lost significance after inverse probability weights. Patients in the PED cohort were associated with higher rates of periprocedural complications (3.5% vs 0%; P = .573), and the rate of in-stent stenosis was approximately double in the FRED cohort (15.2% vs 6.9%; P = .172).Compared with PED, FRED offers modest 6-month occlusion rates, which may be due to aneurysmal and baseline patient characteristics differences between both cohorts. Although not significant, FRED was associated with a higher complication rate mostly because of in-stent stenosis. Additional studies with longer follow-up durations should be conducted to further evaluate FRED thrombogenicity.

OBJECTIVEThe advent of mechanical thrombectomy (MT) has become an effective option for the treatment of acute ischemic stroke in addition to tissue plasminogen activator (tPA). With recent advances in device technology, MT has significantly altered the hospital course and functional outcomes of stroke patients. The authors’ goal was to establish the most up-to-date reperfusion and functional outcomes with the evolution of MT technology.METHODSThe authors conducted a retrospective study of 403 patients who underwent MT for ischemic stroke at their institution from 2010 to 2017. They collected data on patient comorbidities, National Institutes of Health Stroke Scale (NIHSS) score on arrival, tPA administration, revascularization outcomes, and functional outcomes on discharge.RESULTSIn 403 patients, the mean NIHSS score on presentation was 15.8 ± 6.6, with 195 (48.0%) of patients receiving tPA prior to MT. Successful reperfusion (thrombolysis in cerebral infarction score 2B or 3) was achieved in 84.4%. Hemorrhagic conversion with significant mass effect was noted in 9.9% of patients. The median lengths of ICU and hospital stay were 3.0 and 7.0 days, respectively. Functional independence (modified Rankin Scale score 0–2) was noted in 125 (31.0%) patients, while inpatient mortality occurred in 43 (10.7%) patients.CONCLUSIONSAs MT has established acute ischemic stroke as a neurosurgical disease, there is a pressing need to understand the hospital course, hospital- and procedure-related complications, and outcomes for this new patient population. The authors provide a detailed account of key metrics for MT with the latest device technology and identify the predictors of unfavorable outcomes and inpatient mortality.

Study Design: Literature review. Objectives: Paraspinal muscle integrity is believed to play a critical role in low back pain (LBP) and numerous spinal deformity diseases and other pain pathologies. The influence of paraspinal muscle atrophy (PMA) on the clinical and radiographic success of spinal surgery has not been established. We aim to survey the literature in order to evaluate the impact of paraspinal muscle atrophy on low back pain, spine pathologies, and postoperative outcomes of spinal surgery. Methods: A review of the literature was conducted using a total of 267 articles identified from a search of the PubMed database and additional resources. A full-text review was conducted of 180 articles, which were assessed based on criteria that included an objective assessment of PMA in addition to measuring its relationship to LBP, thoracolumbar pathology, or surgical outcomes. Results: A total of 34 studies were included in this review. The literature on PMA illustrates an association between LBP and both decreased cross-sectional area and increased fatty infiltration of paraspinal musculature. Atrophy of the erector spinae and psoas muscles have been associated with spinal stenosis, isthmic spondylolisthesis, facet arthropathy, degenerative lumbar kyphosis. A number of studies have also demonstrated an association between PMA and worse postoperative outcomes. Conclusions: PMA is linked to several spinal pathologies and some studies demonstrate an association with worse postoperative outcomes following spinal surgery. There is a need for further research to establish a relationship between preoperative paraspinal muscle integrity and postoperative success, with the potential for guiding surgical decision making.

The sphenopalatine ganglion (SPG) is a vasoactive mediator of the anterior intracranial circulation in mammals. SPG stimulation has been demonstrated to alter blood-brain barrier (BBB) permeability, although this phenomenon is not well characterized.To determine the effect of SPG stimulation on the BBB using rat models.Extravasation of fluorescent tracer 70 kDa FITC-dextran into rat brain specimens was measured across a range of stimulation parameters to assess BBB permeability. Tight junction (TJ) morphology was compared by assessing differences in the staining of proteins occludin and ZO-1 and analyzing ultrastructural changes on transmission electron microscopy (TEM) between stimulated and unstimulated specimens.SPG stimulation at 10 Hz maximally increased BBB permeability, exhibiting a 6-fold increase in fluorescent traceruptake (1.66% vs 0.28%, p 0.0001). This effect was reversed 4-hours after stimulation (0.36% uptake, p = 0.99). High-frequency stimulation at 20 Hz and 200 Hz did not increase tracer extravasation, (0.26% and 0.28% uptake, p = 0.999 and p = 0.998, respectively). Stimulation was associated a significant decrease in the colocalization of occludin and ZO-1 with endothelial markers in stimulated brains compared to control (74.6% vs. 39.7% and 67.2% vs. 60.4% colocalization, respectively, p 0.0001), and ultrastructural changes in TJ morphology associated with increased BBB permeability were observed on TEM.This study is the first to show a reversible, frequency-dependent increase in BBB permeability with SPG stimulation and introduces a putative mechanism of action through TJ disruption. Bypassing the BBB with SPG stimulation could enable new paradigms in delivering therapeutics to the CNS. Further study of this technology is needed.

Rapid reperfusion of ischemic penumbra in patients with acute stroke is critical to neurological recovery. Achieving reperfusion after first-pass mechanical thrombectomy has been associated with improved patient outcomes. However, the predictors for obtaining first-pass reperfusion are not well known.A single-institution retrospective study of all patients who underwent mechanical thrombectomy at a tertiary care center from January 2010 until March 2019 was conducted to assess for predictors of first-pass reperfusion.A total of 257 patients were reviewed. Successful reperfusion was obtained in 63.4% of patients, and in 38% of patients on the first pass. On multivariate analysis, increasing door-to-puncture time was a negative predictor of FPR (OR 0.989, 95% CI = 0.980-0.997) and use of combined thrombectomy technique with stent-retriever and aspiration was a positive predictor of FPR compared to aspiration or stent-retriever alone (OR 4.441, 95% CI = 1.001-19.699).Combination therapy using stent-retriever and aspiration may increase the chance of obtaining FPR, whereas delays in starting the procedure after patient arrival may decrease the odds of FPR. Rapid thrombectomy initiation and procedural technique may play in optimizing rates of FPR and ultimately patient outcomes, however, randomized controlled trials assessing these variables are necessary to determine optimal treatment strategies.

Introduction Novel machine learning (ML) methods are being investigated across medicine for their predictive capabilities while boasting increased adaptability and generalizability. In our study, we compare logistic regression with machine learning for feature importance analysis and prediction in first-pass reperfusion. Methods We retrospectively identified cases of ischemic stroke treated with mechanical thrombectomy (MT) at our institution from 2012–2018. Significant variables used in predictive modeling were demographic characteristics, medical history, admission NIHSS, and stroke characteristics. Outcome was binarized TICI on first pass (0-2a vs 2b-3). Shapley feature importance plots were used to identify variables that strongly affected outcomes. Results Accuracy for the Random Forest and SVM models were 67.1% compared to 65.8% for the logistic regression model. Brier score was lower for the Random Forest model (0.329 vs 0.342) indicating better predictive capability. Other supervised learning models performed worse than the logistic regression model, with accuracy of 56.2% for Naive Bayes and 61.6% for XGBoost. Shapley plots for the Random Forest model showed use of aspiration, hyperlipidemia, hypertension, use of stent retriever, and time between symptom onset and catheterization as the top five predictors of first pass reperfusion. Conclusion Use of machine learning models, such as Random Forest, for the study of MT outcomes, is more accurate than logistic regression for our dataset, and identifies new factors that contribute to achieving first pass reperfusion. The benefits of machine learning, such as improved predictive capabilities, integration of new data, and generalizability, establish ML as the preferred model for studying outcomes in stroke.

Neuroangiography has seen a recent shift from transfemoral to transradial access. In transradial neuroangiography, the right dominant hand is the main access used. However, the left side may be used specifically for left posterior circulation pathologies and when right access cannot be used. This study describes our initial experience with left radial access for diagnostic neuroangiography and assesses the feasibility and safety of this technique. We performed a retrospective review of a prospective database of consecutive patients between April 2018 and January 2020, and identified 20 patients whom a left radial access was used for neurovascular procedures. Left transradial neuroangiography was successful in all 20 patients and provided the sought diagnostic information; no patient required conversion to right radial or femoral access. Pathology consisted of anterior circulation aneurysms in 17 patients (85%), brain tumor in 1 patient (5%), and intracranial atherosclerosis disease involving the middle cerebral artery in 2 patients (10%). The left radial artery was accessed at the anatomic snuffbox in 18 patients (90%) and the wrist in 2 patients (10%). A single vessel was accessed in 7 (35%), two vessels in 8 (40%), three vessels in 4 (20%), and four vessels in 1 (5%). Catheterization was successful in 71% of the cases for the right internal carotid artery and in only 7.7% for the left internal carotid artery. There were no instances of radial artery spasm, radial artery occlusion, or procedural complications. Our initial experience found the left transradial access to be a potentially feasible approach for diagnostic neuroangiography even beyond the left vertebral artery. The approach is strongly favored by patients but has significant limitations compared with the right-sided approach.

Errors in communication are a major source of preventable medical errors. Neurosurgical patients frequently present to the neuro-intensive care unit (NICU) postoperatively, where handoffs occur to coordinate care within a large multidisciplinary team. A multidisciplinary working group at our institution started an initiative to improve postoperative neurosurgical handoffs using validated quality improvement methodology. Baseline handoff practices were evaluated through staff surveys and serial observations. A formalized handoff protocol was implemented using the evidence based IPASS format (Illness severity, Patient summary, Action list, Situational awareness and contingency planning, Synthesis by receiver). Cycles of objective observations and surveys were employed to track practice improvements and guide iterative process changes over one year. Surveys demonstrated improved perceptions of handoffs as organized (17.1% vs 69.7%, p 0.001), efficient (27.0% vs. 72.7%, p 0.001), comprehensive (17.1% vs. 66.7%, p 0.001), and safe (18.0% vs. 66.7%, p 0.001), noting improved teamwork (31.5% vs. 69.7%, p 0.001). Direct observations demonstrated improved communication of airway concerns (47.1% observed vs. 92.3% observed, p 0.001), hemodynamic concerns (70.6% vs. 97.1%, p = 0.001), intraoperative events (52.9% vs. 100%, p 0.001), neurological examination (76.5% vs. 100%, p 0.001), vital sign goals (70.6% vs. 100%, p 0.001), and required postoperative studies (76.5% vs. 100%, p 0.001). Receiving teams demonstrating improved rates of summarization (47.1% vs. 94.2%, p = 0.005) and asking questions (76.5% vs 98.1%, p = 0.004). The mean handoff time during long-term follow-up was 4.4 min (95% confidence interval = 3.9-5.0 min). Standardization of handoff practices yields improvements in communication practices for postoperative neurosurgical patients.

OBJECTIVE In this study, the authors aimed to investigate procedural and clinical outcomes between radial and femoral artery access in patients undergoing thrombectomy for acute stroke. METHODS The authors conducted a single-institution retrospective analysis of 104 patients who underwent mechanical thrombectomy, 52 via transradial access and 52 via traditional transfemoral access. They analyzed various procedural and clinical metrics between the two patient cohorts. RESULTS There was no difference between patient demographics or presenting symptoms of stroke severity between patients treated via transradial or transfemoral access. The mean procedural time was similar between the two treatment cohorts: 60.35 ± 36.81 minutes for the transradial group versus 65.50 ± 29.92 minutes for the transfemoral group (p = 0.451). The mean total fluoroscopy time for the procedure was similar between the two patient cohorts (20.31 ± 11.68 for radial vs 18.49 ± 11.78 minutes for femoral, p = 0.898). The majority of patients underwent thrombolysis in cerebral infarction score 2b/3 revascularization, regardless of access site (92.3% for radial vs 94.2% for femoral, p = 0.696). There was no significant difference in the incidence of access site or periprocedural complications between the transradial and transfemoral cohorts. CONCLUSIONS Acute stroke intervention performed via transradial access is feasible and effective, with no significant difference in procedural and clinical outcomes compared with traditional transfemoral access. Larger studies are required to further validate the efficacy and limitations of transradial access for neurointerventional procedures.

Sphenopalatine ganglion (SPG) stimulation has been shown to reversibly alter blood-brain barrier (BBB) permeability. It is widely used for the treatment of cluster headaches in Europe and is well tolerated in humans. The therapeutic potential for SPG stimulation in other central nervous system (CNS) diseases has yet to be explored. Glioblastoma Multiforme (GBM) remains one of the most difficult primary CNS neoplasms to treat, with an average survival of approximately 18 months at the time of diagnosis. Since 2004, the gold standard of treatment for GBM in the United States includes surgery followed by treatment with temozolomide (TMZ) and radiation. We sought to determine if SPG stimulation could increase chemotherapy concentrations in rodent brains with an intact BBB. Here, we show a statistically significant (p = 0.0006), five-fold upregulation of TMZ crossing the BBB and reaching brain parenchyma in rats receiving low-frequency (LF, 10 Hz) SPG stimulation. All the measurements were performed using a highly sensitive liquid chromatography mass spectrometry (LCMS) method that was developed for quantitation of TMZ in plasma and brain tissue. Our treatment paradigm shows novel delivery route by which we could more effectively and safely deliver TMZ in a targeted manner, to minimize systemic toxicity and maximize action at the target tissue.

Background Aneurysms associated with fenestrations of intracranial arteries are exceptionally rare findings. Management strategies for these aneurysms are not well-defined, especially regarding endovascular treatment. We sought to investigate the strategies and feasibility of endovascular treatment approaches for various fenestration-associated intracranial aneurysms. Methods We performed a retrospective chart review of 2000 aneurysms treated endovascularly, identifying 8 aneurysms located at arterial fenestrations. The technical details and procedural outcomes were reviewed to identify common management approaches, technical nuances, and treatment outcomes. Results There were 3 (37.5%) aneurysms associated with fenestrations of the basilar artery or vertebrobasilar junction. All 3 were successfully treated with a previously undescribed coil-assisted flow-diversion technique, resulting in complete obliteration. Three (37.5%) aneurysms were associated with fenestrations of the anterior communicating artery. Of those, 2 were successfully treated with stent-assisted coil embolization and 1 with coil embolization alone. One (12.5%) aneurysm was associated with a fenestration of the paraclinoid internal carotid artery and 1 (12.5%) aneurysm found was at the takeoff of the posterior inferior cerebellar artery at a fenestration of the vertebral artery. Both were successfully treated with coil-assisted flow diversion. There were no permanent procedural complications. Major considerations for endovascular management of these aneurysms were the dominance of fenestration trunks, aneurysms arising from the fenestration apex or a fenestration limb, amenability to flow diversion, and anticipation of vascular remodeling. Conclusions Fenestration-associated aneurysms are very rare. We have identified common factors to help guide decision-making for endovascular approaches and demonstrate successful aneurysm treatment using these methods.

BackgroundEmergence of the novel corona virus (severe acute respiratory syndrome (SARS)-CoV-2) in December 2019 has led to the COVID-19 pandemic. The extent of COVID-19 involvement in the central nervous system is not well established, and the presence or the absence of SARS-CoV-2 particles in the cerebrospinal fluid (CSF) is a topic of debate.Case descriptionWe present two patients with COVID-19 and concurrent neurological symptoms. Our first patient is a 31-year-old man who had flu-like symptoms due to COVID-19 and later developed an acute-onset severe headache and loss of consciousness and was diagnosed with a Hunt and Hess grade 3 subarachnoid haemorrhage from a ruptured aneurysm. Our second patient is a 62-year-old woman who had an ischaemic stroke with massive haemorrhagic conversion requiring a decompressive hemicraniectomy. Both patients’ CSF was repeatedly negative on real-time PCR analysis despite concurrent neurological disease.ConclusionOur report shows that patients’ CSF may be devoid of viral particles even when they test positive for COVID-19 on a nasal swab. Whether SARS-CoV-2 is present in CSF may depend on the systemic disease severity and the degree of the virus’ nervous tissue tropism and should be examined in future studies.

Objective Stereoelectroencephalography (sEEG) requires extensive preoperative planning to optimize placement of electrodes and limit the potential for complications. Flat-detector computed tomography (FD-CT) has previously been used for perioperative vascular imaging to guide the treatment of vascular lesions. This imaging modality provides a detailed depiction of cerebrovascular and bony cranial anatomy, which can be used to guide intracranial electrode implantation. We have developed a novel method to improve preoperative planning for sEEG electrode implantation and limit the potential for postoperative complications by using FD-CT imaging merged with preoperative magnetic resonance imaging (MRI). Methods All patients underwent preoperative FD-CT with selective intra-arterial iodinated contrast dye injection through the late arterial and capillary phases for evaluation of cerebrovascular anatomy. These results were merged with thin-cut MRI for trajectory planning of intracranial sEEG electrodes. All patients underwent routine CT and MRI after electrode placement. Results 39 patients have undergone sEEG implantation according to this protocol, with a total of 541 electrodes placed. Additionally, 25 (64.1%) patients underwent implantation of 70 oblique insular electrodes. There were no clinically significant complications after the implantations. Thirty-six (92.3%) patients underwent operative intervention, including surgical resection in 27 (69.2%) patients. Conclusion FD-CT imaging allows for a detailed depiction of cortical cerebrovascular anatomy through the capillary phase, in addition to bony cranial anatomy. This enables the safe planning of complex trajectories, including high-obliquity insular electrodes and transsulcal trajectories through “empty sulci” while also providing concurrent imaging of bony anatomy to allow for preoperative planning of drill depth and anchor placement.

Traumatic CSF leaks are reported to complicate 10–30% of skull base fractures. CSF rhinorrhea or otorrhea may be clinically apparent but in patients with less obvious leaks, β‎2-transferrin evaluation is the most sensitive and specific confirmatory test to establish the diagnosis of CSF leakage. High-resolution CT effectively identifies the majority of skull base fractures and sites of CSF leakage. Adjunctive imaging modalities such as CT cisternography and magnetic resonance cisternography may be used for further evaluation. Most traumatic CSF leaks of the anterior cranial fossa resolve spontaneously with conservative management including bedrest, head elevation, and avoidance of activities that increase intracranial pressure. The risk of meningitis increases significantly with persistent CSF leakage beyond 1 week, and intervention in the form of CSF diversion or surgical closure of the leak should be pursued. Prophylactic antibiotics have not been shown to decrease the risk of meningitis in patients with traumatic CSF leaks.

Unrepaired orbital floor defects after sinonasal and skull-base tumor resection can lead to herniation of orbital contents into the maxillary or ethmoidal sinuses, possibly resulting in infection and significant cosmetic and functional deficits. Orbital floor defects are usually repaired using prosthetic implants or autogenous material. Nasal septal cartilage has been used previously as a free graft for reconstruction. However, its reliance on local vascular supply can result in ischemia and necrosis in the postoperative period. The vascularized pedicled nasoseptal flap, consisting of mucoperichondrium and mucoperiosteum, is routinely used as an effective reconstruction method for endoscopic repair of cerebrospinal fluid leaks arising from skull base dural defects. However, this flap does not provide rigid structural reconstruction when used alone. We report a case of an orbital floor defect repaired using a pedicled mucochondral-osteal nasoseptal flap. This technique incorporates the structural component of the nasal septal cartilage and bone with the vascularized pedicled nasoseptal flap. This repair technique may be useful in patients requiring postoperative radiotherapy.

Central neurocytomas are rare benign tumors of the central nervous system that are typically located in the lateral ventricles. Since they were first reported in the early 1980s, many advancements have been made in terms of their diagnosis and treatment. Despite the progress made, the origin of these rare tumors and effective newer treatment strategies remain elusive. Central neurocytomas represent 0.1–0.5% of all primary brain tumors. Since they are typically intraventricular, these tumors tend to present clinically with hydrocephalus. CT scanning and MRI are useful in localizing these tumors; however, due to their numerous ambiguous features, the ultimate diagnosis relies on immunohistochemistry and electron microscopy studies of sampled tissue. Currently, surgical removal with a gross-total resection of these tumors is the treatment of choice. Various radiotherapy techniques, including both conventional radiotherapy and stereotactic radiosurgery, have been shown to be useful in cases of residual tumor after sub-total resection and tumor recurrence. The benign nature of these tumors tends to offer a favorable outcome for most patients; however, recurrence rates are relatively high and tumors with high-grade features or extraventricular location tend to have a less favorable prognosis. We present a comprehensive review of these rare tumors, including their epidemiology, clinical presentation, radiological presentation, histopathological findings, and options for intervention including surgery, radiation therapy, stereotactic radiosurgery, and chemotherapy.

Peer assessment has been shown to be an effective tool to promote professionalism in medical students. Peer assessment may be particularly useful in anatomy dissection laboratory as the required close collaboration and long hours of anatomy laboratory provide students insights into their peers' work habits and interpersonal skills. The objective of this study was to quantitatively and qualitatively analyze the use of a validated peer assessment tool in Gross Anatomy. Students in a first year medical school class evaluated three members of their dissection group using an online survey tool. The mid-course and end-of-course evaluation included open-ended comments, as well as a five-point scale that measured three work habits, two interpersonal attributes and one overall score. All 267 students completed the assignment. The overall score and four of the five other assessed categories showed significant improvement from the mid- to end-of-course evaluations. Quantitative and qualitative data also revealed significant improvement among the students who received the lowest mid-course assessments. Seventy-six percent of the class agreed with the statement: "Based on the feedback I received, I made a change in how I worked with or taught my peers." The use of this peer assessment tool used by students in anatomy was associated with improvements in work habits and interpersonal attributes, particularly by the cohort of students who received the lowest mid-course feedback. Peer assessment offers students an opportunity to improve their interpersonal skills and work habits.

Teratomas of the spinal cord are incredibly rare, comprising less than 0.5% of all spinal cord tumors. These tumors are exceptionally rare in adults, with only a handful of cases reported in the literature. We present the case of a 49-year-old gentleman with new onset urinary incontinence who presented with a large intradural tumor of the thoracolumbar spine. The patient underwent a laminectomy with midline durotomy for subtotal tumor resection. Surgical pathology diagnosed the tumor as a mature teratoma, exhibiting the presence of all three germ layers. These tumors tend to present with an indolent onset of symptoms characteristic of the tumor location within the spinal cord and the affected surrounding nerve roots. Magnetic resonance imaging (MRI) is useful in determining the location and nature of these tumors, but final diagnosis ultimately rests on histopathological analysis. Surgical resection is the preferred treatment, with subtotal resection being favored if there is a high risk of intraoperative neurological damage due to adherent or infiltrative tumor. In general, the prognosis for these tumors is good, with most patients exhibiting stable or improved neurological status after resection.

SummaryObjective Intracranial monitoring is fundamental to epilepsy surgery, with reported complication rates of 3–17%. We aimed to assess the differences in complication rates between subdural and depth electrodes. Methods We conducted a retrospective review of 317 electrode implantation procedures. All documented abnormal postoperative findings were recorded in our study. Those that resulted in a significant alteration of treatment course, including neurologic deficit, long-term medication use, reoperation, or hospital readmission, were deemed clinically significant. When possible, findings were attributed to a particular electrode type based on relative location to each electrode. Results Postoperative abnormalities were associated with SDE placement in 152 (47.9%) procedures and 40 (25.2%) DE placements (p < 0.001). Twenty-nine (9.1%) clinically significant complications were seen in the subdural electrode (SDE) group compared to 10 associated with DEs (6.3%, p = 0.37). SDEs were associated with increased rates of any postoperative hemorrhage (p < 0.001) or extraaxial collection (p = 0.007). Subdural grid placement was associated with an increased risk of any extraaxial collection (odds ratio [OR 2.42), as well as clinically significant collections (OR 9.47). Previous craniotomy was found to be associated with any abnormal postoperative finding (OR 1.71) as well as radiographic hemorrhage (OR 1.99). Concurrent resection is also associated with abnormal findings (OR 1.83) and extraaxial collections (OR 2.37). The overall complication rate was 9.1%, with 13 procedures (4.1%) resulting in neurologic deficit. However, only two patients (0.6%) had permanent neurologic sequelae resulting from lead placement. Significance Subdural electrodes appear to have an increased rate of abnormal postoperative findings, including hemorrhage and extraaxial collections; however, there was no difference in clinically significant findings. Subdural grids also appear to be associated with symptomatic extraaxial collections, and previous craniotomy increases the risk of hemorrhage. Overall, intracranial monitoring remains a safe and effective procedure for localization of operative seizure foci. Patient selection and risk education for various modalities is an essential aspect of preoperative evaluation.

The highly homologous proteins ezrin, radixin, and moesin link proteins to the actin cytoskeleton. The two family members expressed in T cells, ezrin and moesin, are implicated in promoting T cell activation and polarity. To elucidate the contributions of ezrin and moesin, we conducted a systematic analysis of their function during T cell activation. In response to TCR engagement, ezrin and moesin were phosphorylated in parallel at the regulatory threonine, and both proteins ultimately localized to the distal pole complex (DPC). However, ezrin exhibited unique behaviors, including tyrosine phosphorylation and transient localization to the immunological synapse before movement to the DPC. To ask whether these differences reflect unique requirements for ezrin vs moesin in T cell signaling, we generated mice with conditional deletion of ezrin in mature T cells. Ezrin−/− T cells exhibited normal immunological synapse organization based upon localization of protein kinase C-θ, talin, and phospho-ZAP70. DPC localization of CD43 and RhoGDP dissociation inhibitor, as well as the novel DPC protein Src homology region 2 domain-containing phosphatase-1, was also unaffected. However, recruitment of three novel DPC proteins, ezrin binding protein of 50 kDa, Csk binding protein, and the p85 subunit of PI3K was partially perturbed. Biochemical analysis of ezrin−/− T cells or T cells suppressed for moesin using small interfering RNA showed intact early TCR signaling, but diminished levels of IL-2. The defects in IL-2 production were more pronounced in T cells deficient for both ezrin and moesin. These cells also exhibited diminished phospholipase C-γ1 phosphorylation and calcium flux. We conclude that despite their unique movement and phosphorylation patterns, ezrin and moesin function together to promote T cell activation.

Tumors of the skull base have historically posed a unique surgical challenge. The abundance of critical neurovascular structures in this region necessitates a distinct balance between the goals of maximal tumor removal and avoidance of neurological deficits. A number of these lesions do not have a set standard treatment paradigm, thus requiring a highly personalized plan of care based around the individual patient. Surgical resection of these lesions has the benefit of allowing direct decompression of the neurovascular elements, potentially leading to significant clinical improvement. Additionally, in a number of scenarios, surgery may be the only treatment option that offers a cure. On the other hand, the primary goal of stereotactic radiosurgery is tumor control, preventing further growth of an existing tumor or residual lesion. The desired therapeutic intervention should be determined based on various factors including the individual patient’s age, symptoms, comorbidities, tumor location, and extent of the involvement of surrounding neurovascular structures. This chapter discusses the surgical considerations for a variety of skull base tumors, including indications for surgery, surgical approaches, and patient outcomes. Due to the variability in location, natural history, and clinical presentation of skull base tumors, the discussion will illustrate the different surgical considerations for specific tumors, including trigeminal schwannomas, glomus jugulare tumors, chordomas, chondrosarcomas, esthesioneuroblastomas, craniopharyngiomas, and skull base meningiomas.

Unrepaired orbital floor defects after sinonasal and skull-base tumor resection can lead to herniation of orbital contents into the maxillary or ethmoidal sinuses, possibly resulting in infection and significant cosmetic and functional deficits. Orbital floor defects are usually repaired using prosthetic implants or autogenous material. Nasal septal cartilage has been used previously as a free graft for reconstruction. However, its reliance on local vascular supply can result in ischemia and necrosis in the postoperative period. The vascularized pedicled nasoseptal flap, consisting of mucoperichondrium and mucoperiosteum, is routinely used as an effective reconstruction method for endoscopic repair of cerebrospinal fluid leaks arising from skull base dural defects. However, this flap does not provide rigid structural reconstruction when used alone. We report a case of an orbital floor defect repaired using a pedicled mucochondral-osteal nasoseptal flap. This technique incorporates the structural component of the nasal septal cartilage and bone with the vascularized pedicled nasoseptal flap. This repair technique may be useful in patients requiring postoperative radiotherapy.

Object Malignant peripheral nerve sheath tumors (MPNSTs) are a rare form of malignancy arising from the Schwann cells of peripheral nerves. MPNSTs of the trigeminal nerve are exceptionally rare, with only a handful of reports in the literature. These tumors are typically very aggressive, resulting in significant patient morbidity and a generally grim prognosis. Most current reports suggest that radical resection with radiation therapy offers the best benefit. In this study, the authors systematically reviewed the world English-language literature on MPNSTs of the trigeminal nerve to analyze the presentations, treatment options, and outcomes for patients with this disease. Methods A literature search for MPNSTs of the trigeminal nerve confined to nonanimal, English-language articles was conducted utilizing the PubMed database, with additional cases chosen from the references of selected articles. Only cases of confirmed MPNSTs of the trigeminal nerve or its peripheral branches, based upon surgical, pathological, or radiological analysis, were included. Results From the literature search, 29 articles discussing 35 cases of MPNSTs of the trigeminal nerve were chosen. With the addition of 1 case from their own institution, the authors analyzed 36 cases of trigeminal MPNSTs. The average age of onset was 44.6 years. These tumors were more commonly seen in male patients (77.1%). The gasserian ganglion was involved in 36.1% of the cases. Of the cases in which the nerve distribution was specified (n = 25), the mandibular branch was most commonly involved (72.0%), followed by the maxillary branch (60.0%) and the ophthalmic branch (32.0%), with 44.0% of patients exhibiting involvement of 2 or more branches. Altered facial sensation and facial pain were the 2 most commonly reported symptoms, found in 63.9% and 52.8% of patients, respectively. Mastication difficulty and diplopia were seen in 22.2% of patients, facial weakness was seen in 19.4%, and hearing loss was present in 16.7%. With regard to the primary treatment strategy, 80.6% underwent resection, 16.7% underwent radiation therapy, and 2.9% received chemotherapy alone. Patients treated with complete resection followed by postoperative radiation therapy had the most favorable outcomes, with no patients showing evidence of disease recurrence with a mean follow-up of 34.6 months. Patients treated with incomplete resection followed by postoperative radiation therapy had more favorable outcomes than patients treated with incomplete resection without radiation therapy or radiation therapy alone. Conclusions Trigeminal MPNSTs most commonly present as altered facial sensation or facial pain, although they exhibit a number of other clinical manifestations, including the involvement of other cranial nerves. While a variety of treatment options exist, due to their highly infiltrative nature, aggressive resection followed by radiation therapy appears to offer the greatest chance of recurrence-free survival.

This chapter identifies and discusses a general software development process that involves a number of sequential stages of development and intermediary, transitional project reviews. The purpose of this discussion is to set the basis for explaining how software engineering practices are applied throughout the software development effort. The software breakdown structure is discussed to describe how the software architecture evolves throughout the development process.

This chapter discusses the role of stakeholders within the software development effort. It focuses on understanding stakeholder motivations and the need to properly grasp stakeholder needs and expectations as they impact software requirements. The relationships between stakeholder needs, software requirements, and project planning are examined. The need to solicit stakeholder demands and balance and resolve conflicting demands is discussed. The emphasis is on explaining the importance of software engineering practices and establishing a comprehensive and achievable set of software requirements. The chapter examines the role of continual interaction with stakeholders as the software requirements are translated into the software architecture.

This chapter investigates the challenges associated with the development of a software product. This investigation concentrates on identifying the inherent features of software that obstruct the design of software products and the informal practices applied to influence a software design. The characteristics of software as a “raw material” are discussed, which contributes to the challenges of fashioning a software product. This exploration investigates the history of programming as it has evolved since Charles Babbage designed the first programmable computer, called the Analytical Engine, in 1837. The history of software development is examined to expose the challenges that threaten every software development project. The value of software engineering is substantiated to demonstrate how software engineering provides a progressive, disciplined, and beneficial approach to software development.

This chapter identifies and discusses the software architecture that is the basis for technical and project planning and control. The engineering drawings, diagrams, and models that are used to describe the software architecture are discussed. The relationships among the elements of the software architecture are described to highlight the challenge associated with tracing requirements among the elements of the software architecture.

This chapter discusses the challenges associated with performing software engineering within a software development effort. The project environment imposes many project and technical management processes and procedures that are intended to control the deviation of the technical effort from achieving project objectives. The software engineering effort must be tightly coupled with project management mechanisms to ensure that the software development effort is successfully concluded. In addition, software engineering is responsible for ensuring that the software architecture is established in a manner that reduces software complexity and enables software implementation and testing to be accomplished according to plans, schedules, and budgets.

This chapter discusses the various techniques that should be employed to properly manage software requirements and control the impact of change on the project. Requirements traceability must be expanded to track requirements back to the originating source of stakeholder needs, as well as throughout the software product architecture. This expanded traceability is intended to ensure that the resulting structural component and unit specifications will provide a complete and consistent representation of the software requirements baseline. Change control involves ensuring that every proposed change is properly assessed in terms of its full impact on the software architecture and the work effort necessary to implement and test the synchronized software product. Finally, requirements traceability throughout the software product architecture is critical to satisfying the software functional and physical configuration audits.

This chapter identifies the specific tasks that contribute to the functional analysis and allocation practice. It addresses the complexity assessment of identified functions to determine if further simplification is warranted by decomposing and understanding lower-level functional behaviors. Behavioral modeling tasks are identified to provide a basis for preparing unambiguous representation of software product data processing tasks. The behavioral models provide a basis for performance and resource utilization analysis. The overall architecture is assessed to ensure it is fundamentally noncomplex, internally consistent, and compliant with the established software requirements baseline.

This chapter provides a generic set of tasks for the various software organizations involved in software engineering during the software requirements definition stage. The software requirements definition stage of development translates stakeholder needs, expectations, and constraints into a balanced and achievable set of software requirements. This involves developing the specifications for the software product, the computing environment, and the post-development processes. The computing environment imposes constraints on how the software product operates to support data transaction processes. A key artifact of this stage is a model of the business or embedded systems process it is intended to enable. The operational model forms the basis for deriving the software product, computing environment, and software interface requirements. The software requirements definition stage concludes with the software requirements review.

This chapter discusses the software product functional architecture and its various forms of representation. It also provides guidance to promote the manner in which the function architecture is derived. The functional architecture provides an operational view of the software product with no physical or structural features. It provides an interpretation and translation of software product requirements and the operational model in a software product behavioral representation. The functional architecture provides a basis for determining a noncomplex structural solution.