Initial experience with transcarotid arterial revascularization with flow reversal in the management of symptomatic carotid stenosis.

OBJECTIVE: The aim of this study was to evaluate the efficacy of transcarotid arterial revascularization (TCAR) as a viable intervention in the treatment of symptomatic carotid artery stenosis. METHODS: The authors performed a retrospective review of prospectively collected data of the first 62 consecutive patients treated at Rhode Island Hospital in Providence, Rhode Island, who underwent a TCAR for symptomatic carotid artery stenosis between November 11, 2020, and March 31, 2022. Relevant demographic, comorbidity, and perioperative data were extracted through retrospective chart review. Patients with asymptomatic carotid artery stenosis were excluded. The authors also evaluated patients using pertinent physiological and anatomical high-risk criteria as described in the ROADSTER trial. Risk factors were aggregated to form a composite risk total for every patient. The primary outcome of this study was the 30-day adverse outcome rate of stroke, myocardial infarction, and/or death. Periprocedural stroke was identified by clinical symptoms and radiographic findings. Secondary endpoints included device and procedural success, 30-day mortality, 30-day stroke rate, and postoperative complications. RESULTS: The authors analyzed the first 62 patients with > 50% symptomatic carotid artery stenosis who underwent TCAR at their institution. The mean age of the cohort was 71.5 years, and the cohort was predominantly male (67.7%). The most common high-risk medical criteria were age older than 75 years (45.3%) and severe coronary artery disease (13.6%). The most common anatomical high-risk criteria were high bifurcation (35.1%) and contralateral stenosis requiring treatment within 30 days (15.8%). Fifty percent of patients had at least 1 medical high-risk criterion, 50% had at least 1 anatomical risk criterion, and 82% of patients had 2 or more high-risk criteria of any kind. Among this group, all patients (100%) underwent successful revascularization, with 1 (1.6%) requiring intraprocedural conversion to carotid endarterectomy. Postprocedurally, there was 1 nondisabling stroke (1.6%) and 3 deaths (4.8%) within 30 days of the procedure, with only 1 death directly attributable to the procedure. One patient (1.6%) experienced a neck hematoma. In total, 4 patients (6.5%) experienced a major complication. The overall complication rate was 8.0%. CONCLUSIONS: The authors' initial experience with TCAR suggests that it might provide an effective alternative to carotid endarterectomy and carotid artery stenting in the management of symptomatic carotid stenosis in patients with high-risk anatomical and medical characteristics.

Marital Status Independently Predicts Mortality in Adult Patients with Craniopharyngioma: A SEER-Based Study.

BACKGROUND: The relationship between marital status and overall survival (OS) in adult patients with craniopharyngioma has not been explored in depth. We aimed to elucidate the impact of marital status on the prognosis of craniopharyngioma patients excluding bias from baseline demographics and treatment. METHODS: We extracted 1539 patients diagnosed with craniopharyngioma between 2000 and 2019 from the Surveillance, Epidemiology, and End Results database and divided patients into 4 marital subgroups: married, single, divorced/separated, and widowed. Kaplan-Meier curves with a log-rank test were used to discern differences in OS between marital subgroups. Univariate and multivariate Cox regression were used to identify independent prognostic factors of mortality. RESULTS: There were 1539 eligible patients: 863 (56.1%) were married, 466 (30.3%) were single, 135 (8.8%) were divorced/separated, and 75 (4.9%) were widowed. Widowed patients had the worst mean OS, 5-year OS and 10-year OS at 84.2 months, 58.0% and 26.9%, respectively. After stratifying patients by age, our multivariate analysis showed that marital status was an independent predictor of mortality in middle-aged craniopharyngioma patients (40-60 years, P < 0.001), but not in young adults (18-39 years, P = 0.646) or elderly patients (>60 years, P = 0.076). Among middle-aged patients, single (hazard ratio 1.72, confidence interval 1.19-2.47, P = 0.004) and divorced/separated patients (hazard ratio = 2.29, confidence interval = 1.49-3.54, P < 0.001) showed a higher risk of mortality compared to married patients (reference). CONCLUSIONS: Marital status is an independent prognostic factor predicting OS for middle-aged patients with craniopharyngioma. Providing additional social and psychological support for single and divorced/separated patients may improve outcomes for this vulnerable population.

Endoscopic Techniques for Spinal Oncology: A Systematic Literature Review.

BACKGROUND: Due to its ultraminimally invasive nature, endoscopic spinal surgery is an attractive tool in spinal oncologic care. To date, there has been no comprehensive review of this topic. The authors therefore present a thorough search of the medical literature on endoscopic techniques for spinal oncology. METHODS: A systematic review using PubMed was conducted using the following keywords: endoscopic spine surgery, spinal oncology, and spinal tumors. RESULTS: Collectively, 19 cases described endoscopic spine surgery for spinal oncologic care. Endoscopic spine surgery has been employed for the care of patients with spinal tumors under the following 4 circumstances: (1) to obtain a reliable tissue diagnosis; (2) to serve as an adjunct during traditional open surgery; (3) to achieve targeted debulking; or (4) to perform definitive resection. These cases employing endoscopic techniques highlight the versatility of this approach and its utility when applied to the right patient and with an experienced surgeon. CONCLUSIONS: Our systematic review suggests that, given the right patient and an experienced surgeon, endoscopic spine surgery should be considered in the armamentarium for spinal oncologic care for both staging and definitive resection. CLINICAL RELEVANCE: This systematic literature review showed that endoscopic techniques have been successfully applied across the spectrum of care in spinal oncology, from diagnosis to definitive treatment.

Spatiotemporal Distribution of Electrically Evoked Spinal Compound Action Potentials During Spinal Cord Stimulation.

OBJECTIVES: Recent studies using epidural spinal cord stimulation (SCS) have demonstrated restoration of motor function in individuals previously diagnosed with chronic spinal cord injury (SCI). In parallel, the spinal evoked compound action potentials (ECAPs) induced by SCS have been used to gain insight into the mechanisms of SCS-based chronic pain therapy and to titrate closed-loop delivery of stimulation. However, the previous characterization of ECAPs recorded during SCS was performed with one-dimensional, cylindrical electrode leads. Herein, we describe the unique spatiotemporal distribution of ECAPs induced by SCS across the medial-lateral and rostral-caudal axes of the spinal cord, and their relationship to polysynaptic lower-extremity motor activation. MATERIALS AND METHODS: In each of four sheep, two 24-contact epidural SCS arrays were placed on the lumbosacral spinal cord, spanning the L3 to L6 vertebrae. Spinal ECAPs were recorded during SCS from nonstimulating contacts of the epidural arrays, which were synchronized to bilateral electromyography (EMG) recordings from six back and lower-extremity muscles. RESULTS: We observed a triphasic P1, N1, P2 peak morphology and propagation in the ECAPs during midline and lateral stimulation. Distinct regions of lateral stimulation resulted in simultaneously increased ECAP and EMG responses compared with stimulation at adjacent lateral contacts. Although EMG responses decreased during repetitive stimulation bursts, spinal ECAP amplitude did not significantly change. Both spinal ECAP responses and EMG responses demonstrated preferential ipsilateral recruitment during lateral stimulation compared with midline stimulation. Furthermore, EMG responses were correlated with stimulation that resulted in increased ECAP amplitude on the ipsilateral side of the electrode array. CONCLUSIONS: These results suggest that ECAPs can be used to investigate the effects of SCS on spinal sensorimotor networks and to inform stimulation strategies that optimize the clinical benefit of SCS in the context of managing chronic pain and the restoration of sensorimotor function after SCI.

Gross total resection and survival outcomes in elderly patients with spinal chordoma: a SEER-based analysis.

Objective: The association between aggressive resection and improved survival for adult spinal chordoma patients has not been well characterized in the geriatric population. Thus, the present study aimed to elucidate the relationship between gross total resection (GTR) and survival outcomes for patients across different age groups. Methods: The authors isolated all adult patients diagnosed with spinal chordoma from the 2000-2019 Surveillance, Epidemiology, and End Results database and divided patients into three surgical subgroups: no surgery, subtotal resection (STR), and GTR. Kaplan-Meier curves with a log-rank test were used to discern differences in overall survival (OS) between surgical subgroups. Univariate and multivariate analyses were used to identify prognostic factors of mortality. Results: There were 771 eligible patients: 227 (29.4%) received no surgery, 267 (34.6%) received STR, and 277 (35.9%) received GTR. Patients receiving no surgery had the lowest 5-year OS (45.2%), 10-year OS (17.6%), and mean OS (72.1 months). After stratifying patients by age, our multivariate analysis demonstrated that patients receiving GTR aged 40-59 (HR=0.26, CI=0.12-0.55, p<0.001), 60-79 (HR=0.51, CI=0.32-0.82, p=0.005), and 80-99 (HR=0.14, CI=0.05-0.37, p<0.001) had a lower risk of mortality compared to patients undergoing no surgery. The frequency of receiving GTR also decreased as a function of age (16.4% [80-99 years] vs. 43.2% [20-39 years]; p<0.001), but the frequency of receiving radiotherapy was comparable across all age groups (48.3% [80-99 years] vs. 45.5% [20-39 years]; p=0.762). Conclusion: GTR is associated with improved survival for middle-aged and elderly patients with spinal chordoma. Therefore, patients should not be excluded from aggressive resection on the basis of age alone. Rather, the decision to pursue surgery should be decided on an individual basis.

Development of posttraumatic frontal brain abscess in association with an orbital roof fracture and odontogenic abscess: A case report.

Background: Brain abscess is a potentially fatal condition. Orbital fractures caused by penetrating injury may be associated with intracranial infection. Such complication associated with blunt trauma, orbital roof fractures, and odontogenic abscesses is exceedingly rare. Case Description: We report the case of a 40-year-old transgender female with a frontal abscess presenting several weeks following a motor vehicle crash from which she suffered multiple facial fractures and an odontogenic abscess. On computed tomography scan, the patient had multiple right-sided facial fractures, including a medial orbital wall fracture and a right sphenoid fracture extending into the superior orbital roof. There was hemorrhage notable in the right frontal lobe. Communication with the ethmoid sinuses likely provided a conduit for bacterial spread through the orbit and into the intracranial and subdural spaces. Conclusion: Skull base fractures that communicate with a sinus, whether it be frontal, ethmoid, or sphenoid may increase the risk of brain abscess, especially in patients who develop an odontogenic abscess. Surgical repair of the defect is essential, and treating patients prophylactically with antibiotics may be beneficial.

A Review of Functional Restoration From Spinal Cord Stimulation in Patients With Spinal Cord Injury.

Traumatic spinal cord injury often leads to loss of sensory, motor, and autonomic function below the level of injury. Recent advancements in spinal cord electrical stimulation (SCS) for spinal cord injury have provided potential avenues for restoration of neurologic function in affected patients. This review aims to assess the efficacy of spinal cord stimulation, both epidural (eSCS) and transcutaneous (tSCS), on the return of function in individuals with chronic spinal cord injury. The current literature on human clinical eSCS and tSCS for spinal cord injury was reviewed. Seventy-one relevant studies were included for review, specifically examining changes in volitional movement, changes in muscle activity or spasticity, or return of cardiovascular pulmonary, or genitourinary autonomic function. The total participant sample comprised of 327 patients with spinal cord injury, each evaluated using different stimulation protocols, some for sensorimotor function and others for various autonomic functions. One hundred eight of 127 patients saw improvement in sensorimotor function, 51 of 70 patients saw improvement in autonomic genitourinary function, 32 of 32 patients saw improvement in autonomic pulmonary function, and 32 of 36 patients saw improvement in autonomic cardiovascular function. Although this review highlights SCS as a promising therapeutic neuromodulatory technique to improve rehabilitation in patients with SCI, further mechanistic studies and stimulus parameter optimization are necessary before clinical translation.

Fast inference of spinal neuromodulation for motor control using amortized neural networks.

Objective.Epidural electrical stimulation (EES) has emerged as an approach to restore motor function following spinal cord injury (SCI). However, identifying optimal EES parameters presents a significant challenge due to the complex and stochastic nature of muscle control and the combinatorial explosion of possible parameter configurations. Here, we describe a machine-learning approach that leverages modern deep neural networks to learn bidirectional mappings between the space of permissible EES parameters and target motor outputs.Approach.We collected data from four sheep implanted with two 24-contact EES electrode arrays on the lumbosacral spinal cord. Muscle activity was recorded from four bilateral hindlimb electromyography (EMG) sensors. We introduce a general learning framework to identify EES parameters capable of generating desired patterns of EMG activity. Specifically, we first amortize spinal sensorimotor computations in a forward neural network model that learns to predict motor outputs based on EES parameters. Then, we employ a second neural network as an inverse model, which reuses the amortized knowledge learned by the forward model to guide the selection of EES parameters.Main results.We found that neural networks can functionally approximate spinal sensorimotor computations by accurately predicting EMG outputs based on EES parameters. The generalization capability of the forward model critically benefited our inverse model. We successfully identified novel EES parameters, in under 20 min, capable of producing desired target EMG recruitment duringin vivotesting. Furthermore, we discovered potential functional redundancies within the spinal sensorimotor networks by identifying unique EES parameters that result in similar motor outcomes. Together, these results suggest that our framework is well-suited to probe spinal circuitry and control muscle recruitment in a completely data-driven manner.Significance.We successfully identify novel EES parameters within minutes, capable of producing desired EMG recruitment. Our approach is data-driven, subject-agnostic, automated, and orders of magnitude faster than manual approaches.

Navigation Techniques in Endoscopic Spine Surgery.

Endoscopic spine surgery (ESS) advances the principles of minimally invasive surgery, including minor collateral tissue damage, reduced blood loss, and faster recovery times. ESS allows for direct access to the spine through small incisions and direct visualization of spinal pathology via an endoscope. While this technique has many applications, there is a steep learning curve when adopting ESS into a surgeon's practice. Two types of navigation, optical and electromagnetic, may allow for widespread utilization of ESS by engendering improved orientation to surgical anatomy and reduced complication rates. The present review discusses these two available navigation technologies and their application in endoscopic procedures by providing case examples. Furthermore, we report on the future directions of navigation within the discipline of ESS.

Safety of Sheathless Transradial Balloon Guide Catheter Placement for Acute Stroke Thrombectomy.

BACKGROUND: Transradial access has been described for mechanical thrombectomy in acute stroke, and proximal balloon occlusion has been shown to improve recanalization and outcomes. However, sheathed access requires a larger total catheter diameter at the access site. We aimed to characterize the safety of sheathless transradial balloon guide catheter use in acute stroke intervention. METHODS: Consecutive patients who underwent sheathless right-sided transradial access for thrombectomy with a balloon guide catheter were identified in a prospectively collected dataset from 2019 to 2021. Demographics, procedure details, and short-term outcomes were collected and reported with descriptive statistics. RESULTS: A total of 48 patients (20 women) with a mean age of 72.3 years were identified. Of patients, 56.3% had occlusions in the left-sided circulation; 35 (72.9%) had M1 occlusions, 7 (14.6%) had M2 occlusions, and 6 (12.5%) had internal carotid artery occlusions. Tissue plasminogen activator was administered to 16 (33.3%) patients. Five (10.4%) patients underwent intraprocedural carotid stenting. The cohort had successful reperfusion after a median of 1 (interquartile range: 1, 2) pass. Median time from access to recanalization was 31 (interquartile range: 25, 53) minutes. A postprocedural Thrombolysis In Cerebral Infarction score of ≥2b was achieved in 46 (95.8%) patients. Five patients had wrist access site hematomas. All hematomas resolved with warm compresses, and no further intervention was required. CONCLUSIONS: Sheathless radial access using a balloon guide catheter may be safely performed for acute ischemic stroke with excellent radiographic outcomes. Further investigation is warranted to evaluate the comparative effectiveness of sheathless compared with sheathed transradial balloon guide access.

Incidence, Characteristics, and Outcomes of Pseudomeningocele and Cerebrospinal Fluid Fistula after Posterior Fossa Surgery.

OBJECTIVE: Posterior fossa approaches are common neurosurgical procedures. Rates of postoperative infection, pseudomeningocele, and cerebrospinal fluid (CSF) fistula are high; however, evidence regarding predisposing risk factors and treatment outcomes remain sparse. METHODS: A retrospective cohort study was carried out of all posterior fossa surgeries conducted at a single institution between January 2015 and October 2019. Univariate statistical methods and stepwise logistic regression were used to assess which factors contributed most to risk of development of postoperative complications. RESULTS: A total of 269 patients were included; 18.6% experienced any postoperative complication, 13% developed either pseudomeningocele or CSF fistula, and 9.7% developed an infection. In multivariate analysis, development of a pseudomeningocele was significantly associated with previous cranial surgery (hazard ratio [HR], 3.15; 95% confidence interval [CI], 1.12-9.28; P = 0.0391). Development of a CSF fistula was significantly associated with index surgery for resection of neoplasm (HR, 7.65; 95% CI, 1.86-22.31; P = 0.0174). Development of an infection was significantly associated with concurrent CSF fistula (HR, 7.16; 95% CI, 1.91-23.19; P = 0.0041) and concurrent pseudomeningocele (HR, 3.41; 95% CI, 1.37-5.95; P = 0.0082) and nonsignificantly associated with diabetes requiring treatment (HR, 2.42; 95% CI, 0.69-8.50; P = 0.168). Other hypothesized risk factors for these complications, such as nonmidline approaches to the posterior fossa, watertight duraplasty, use of dural fibrin sealant, and cranioplasty were not associated with these complications on multivariate analysis. Although many patients with pseudomeningocele were successfully managed with observation, only 38% of patients in whom CSF diversion was attempted avoided surgery. CONCLUSIONS: History of diabetes, cranioplasty, revision surgery, and surgery for tumor resection are identified as risk factors for the development of infection, pseudomeningocele, and CSF fistula, respectively.

Utility of automated MRI perfusion (RAPID) with or without MR angiography for detection of angiographic vasospasm after aneurysmal subarachnoid hemorrhage.

Delayed cerebral ischemia (DCI) is a major etiology of poor neurologic outcomes after aneurysmal subarachnoid hemorrhage (aSAH). Although the development of DCI is certainly multifactorial, the presence of vasospasm is strongly correlated with it. Cerebral angiography remains the gold standard for evaluation of vasospasm, though it is not always practical or cost-effective. In this study, the authors assess the utility of automated MRI Perfusion imaging, with or without MR Angiography (MRA), as a confirmatory tool for suspected angiographic vasospasm. All patients admitted to a single institution with aneurysmal subarachnoid hemorrhage between January 2014 and February 2020 and who underwent MR Perfusion imaging with or without MRA for suspected vasospasm no >24 h prior to an angiogram were identified. 43 subjects were identified. 29 of these patients (67%) underwent simultaneous MRA. 25 patients (53%) received intra-arterial treatment for symptomatic vasospasm. The sensitivity, specificity, PPV, and NPV of MR Perfusion were 43%, 82%, 53%, and 75% for any angiographic vasospasm and 57%, 81%, 42%, and 89% for treated vasospasm. The sensitivity, specificity, PPV, and NPV of MR Perfusion in conjunction with MRA were 61%, 81%, 59%, and 82% for any angiographic vasospasm and 62%, 74%, 35%, and 89% for treated vasospasm. The sensitivity, specificity, PPV, and NPV of transcranial Dopplers (TCDs) in these patients were 35%, 93%, 71%, and 75% for angiographic vasospasm and 42%, 90%, 47%, and 88% for treated vasospasm. Automated MR Perfusion imaging demonstrated relatively low sensitivity and PPV for detection of angiographic and treated vasospasm in this subset of patients after aSAH.

Neighborhood-Level Socioeconomic Status Predicts Extended Length of Stay After Elective Anterior Cervical Spine Surgery.

BACKGROUND: A significant portion of health care spending is driven by a small percentage of the overall population. Understanding risk factors predisposing patients to disproportionate use of health care resources is critical. Our objective was to identify risk factors leading to a prolonged length of stay (LOS) after cervical spine surgery. METHODS: A single-center cohort analysis was performed on patients who underwent elective anterior spine surgery from 2015 to 2021. Multivariate logistic regression evaluated the effects of sociodemographic factors including Area of Deprivation Index (quantifies income, education, employment, and housing quality), procedural, and discharge characteristics on postoperative LOS. Extended LOS was defined as greater than the 90th percentile in midnights for the study population (≥3 midnights). RESULTS: A total of 686 patients were included in the study, with a mean age of 57 years (range, 26-92 years), median of 1 level (1-4) fused, and median LOS of 1 midnight (interquartile range, 1-2). After adjusting for confounders, patients had increased odds of extended LOS if they were highly disadvantaged on the Area of Deprivation Index (odds ratio [OR], 2.24; 95% confidence interval [CI], 1.04-4.82; P = 0.039); had surgery on Thursday or Friday (OR, 1.94; 95% CI, 1.01-3.72; P = 0.046); had a corpectomy performed (OR, 2.81; 95% CI, 1.26-6.28; P = 0.012); or discharged not to home (OR, 8.24; 95% CI, 2.88-23.56; P < 0.001). Patients with extended LOS were more likely to present to the emergency department or be readmitted within 30 days after discharge (P = 0.024). CONCLUSIONS: After adjusting for potential cofounders, patients most disadvantaged on Area of Deprivation Index were more likely to have an extended LOS.

Influence of Time of Discharge and Length of Stay on 30-Day Outcomes After Elective Anterior Cervical Spine Surgery.

BACKGROUND: Encouraging early time of discharge (TOD) for medical inpatients is commonplace and may potentially improve patient throughput. It is unclear, however, whether early TOD after elective spine surgery achieves this goal without a consequent increase in re-presentations to the hospital. OBJECTIVE: To evaluate whether early TOD results in increased rates of hospital readmission or return to the emergency department after elective anterior cervical spine surgery. METHODS: We analyzed 686 patients who underwent elective uncomplicated anterior cervical spine surgery at a single institution. Logistic regression was used to evaluate the relationship between sociodemographic, procedural, and discharge characteristics, and the outcomes of readmission or return to the emergency department and TOD. RESULTS: In multiple logistic regression, TOD was not associated with increased risk of readmission or return to the emergency department within 30 days of surgery. Weekend discharge (odds ratio [OR] 0.33, 95% CI 0.21-0.53), physical therapy evaluation (OR 0.44, 95% CI 0.28-0.71), and occupational therapy evaluation (OR 0.32, 95% CI 0.17-0.63) were all significantly associated with decreased odds of discharge before noon. Disadvantaged status, as measured by area of deprivation index, was associated with increased odds of readmission or re-presentation (OR 1.86, 95% CI 0.95-3.66), although this result did not achieve statistical significance. CONCLUSION: There does not appear to be an association between readmission or return to the emergency department and early TOD after elective spine surgery. Overuse of inpatient physical and occupational therapy consultations may contribute to decreased patient throughput in surgical admissions.

Endoscopic Techniques for Lumbar Interbody Fusion: Principles and Context.

Endoscopic techniques in spine surgery are rapidly evolving, with operations becoming progressively safer and less invasive. Lumbar interbody fusion (LIF) procedures comprise many spine procedures that have benefited from endoscopic assistance and minimally invasive approaches. Though considerable variation exists within endoscopic LIF, similar principles and techniques are common to all types. Nonetheless, innovations continually emerge, requiring trainees and experienced surgeons to maintain familiarity with the domain and its possibilities. We present two illustrative cases of endoscopic transforaminal lumbar interbody fusion with a comprehensive literature review of the different approaches to endoscopic LIF procedures.

Intraoperative Monitoring of Spinal Cord Perfusion using Ultrasound in an Ovine Model.

Ultrasound imaging can be used to visualize the spinal cord and assess localized cord perfusion. We present in vivo data in an ovine model undergoing spinal cord stimulation and propose development of transcutaneous US imaging as a potential non-invasive imaging modality in spinal cord injury.Clinical Relevance- Ultrasound imaging can be used to aid in prognosis and diagnosis by providing qualitative and quantitative characterization of the spinal cord. This modality can be developed as a low cost, portable, and non-invasive imaging technique in spinal injury patients.

A survey study examining the motivations, concerns, and perspectives of medical students engaging in neurosurgical research.

BACKGROUND: In a competitive landscape for neurosurgical residency admission, research productivity is increasingly important. Medical school applicants to neurosurgery report high numbers of "scholarly products" as published by the National Residency Match Program. Despite increased student involvement in research and productivity, to the best of our knowledge, no previous reported studies have examined student perspectives on their involvement in neurosurgical research. METHODS: For 2 consecutive years (February 2019 and February 2020), medical students (n = 55) from around the United States presented original research at the Student Neurosurgical Research Conference. Participants were administered a mixed-method survey designed to assess experiences and perspectives on engaging in neurosurgical research. Survey responses were analyzed independently by two researchers to assess for common themes and perspectives. RESULTS: Medical students engaged in all types of research work across nearly every neurosurgical subfield with "Basic/Bench Lab work" (38.5%) and "Chart Review" (23.1%) representing the majority of projects. Students commonly cited "curiosity/interest," and "residency application competitiveness" as main reasons for participation in research. About 66% of respondents reported experiencing anxiety/concern about research productivity "often" or "very often." Thematic analysis revealed that sources of research-related stress were (1) having enough publications to match into residency, and (2) having enough time in medical school to engage in research. CONCLUSION: Medical students engaging in neurosurgical research are highly motivated students driven by scientific curiosity and pressure to prepare for competitive residency applications. Students experience anxiety due to time constraints in medical curricula and increasing demands for scholarly productivity.

Existing clinical evidence on the use of cellular bone matrix grafts in spinal fusion: updated systematic review of the literature.

OBJECTIVE: Spinal fusion surgery is increasingly common; however, pseudarthrosis remains a common complication affecting as much as 15% of some patient populations. Currently, no clear consensus on the best bone graft materials to use exists. Recent advances have led to the development of cell-infused cellular bone matrices (CBMs), which contain living components such as mesenchymal stem cells (MSCs). Relatively few clinical outcome studies on the use of these grafts exist, although the number of such studies has increased in the last 5 years. In this study, the authors aimed to summarize and critically evaluate the existing clinical evidence on commercially available CBMs in spinal fusion and reported clinical outcomes. METHODS: The authors performed a systematic search of the MEDLINE and PubMed electronic databases for peer-reviewed, English-language original articles (1970-2020) in which the articles' authors studied the clinical outcomes of CBMs in spinal fusion. The US National Library of Medicine electronic clinical trials database (www.ClinicalTrials.gov) was also searched for relevant ongoing clinical trials. RESULTS: Twelve published studies of 6 different CBM products met inclusion criteria: 5 studies of Osteocel Plus/Osteocel (n = 354 unique patients), 3 of Trinity Evolution (n = 114), 2 of ViviGen (n = 171), 1 of map3 (n = 41), and 1 of VIA Graft (n = 75). All studies reported high radiographic fusion success rates (range 87%-100%) using these CBMs. However, this literature was overwhelmingly limited to single-center, noncomparative studies. Seven studies disclosed industry funding or conflicts of interest (COIs). There are 4 known trials of ViviGen (3 trials) and Bio4 (1 trial) that are ongoing. CONCLUSIONS: CBMs are a promising technology with the potential of improving outcome after spinal fusion. However, while the number of studies conducted in humans has tripled since 2014, there is still insufficient evidence in the literature to recommend for or against CBMs relative to cheaper alternative materials. Comparative, multicenter trials and outcome registries free from industry COIs are indicated.

Emergency medical services protocols for traumatic brain injury in the United States: A call for standardization.

BACKGROUND: Traumatic brain injury (TBI) with acute elevation in intracranial pressure (ICP) is a neurologic emergency associated with significant morbidity and mortality. In addition to indicated trauma resuscitation, emergency department (ED) management includes empiric administration of hyperosmolar agents, rapid diagnostic imaging, anticoagulation reversal, and early neurosurgical consultation. Despite optimization of in-hospital care, patient outcomes may be worsened by variation in prehospital management. In this study, we evaluate geographic variation between emergency medical services (EMS) protocols for patients with suspected TBI. METHODS: We performed a cross-sectional analysis of statewide EMS protocols in the United States in December 2020 and included all complete protocols published on government websites. Outcome measures were defined to include protocols or orders for the following interventions, given TBI: (1) hyperventilation and end-tidal capnography (EtCO2) goals, (2) administration of hyperosmolar agents, (3) tranexamic acid (TXA) administration for isolated head injury, (4) non-invasive management including head-of-bed elevation, and (5) hemodynamic goals. RESULTS: We identified 32 statewide protocols including Washington, D.C., 4 of which did not include specific guidance for TBI. Of 28 states providing ventilatory guidance, 22/28 (78.6%) recommend hyperventilation, with 17/22 (77.3%) restricting hyperventilation to signs of acute herniation. The remaining 6 states prohibited hyperventilation. Regarding EtCO2 goals among states permitting hyperventilation, 17/22 (77.3%) targeted an EtCO2 of < 35 mmHg, while 5/22 (22.7%) provided no guide EtCO2 for hyperventilation. Rhode Island was the only state identified that included hypertonic saline (3%), and Delaware was the only state that allowed TXA in the setting of isolated TBI with GCS ≤ 12. Only 15/32 (46.9%) identified states recommend head-of-bed elevation. For blood pressure goals, 12/28 (42.9%) of states set minimum systolic blood pressure at 90 mmHg, while 10/28 (35.7%) set other SBP goals. The remaining 6/28 (21.4%) did not provide TBI-specific SBP goals. CONCLUSIONS: There is wide variation among civilian prehospital protocols for traumatic brain injury. Prehospital care within the first "golden hour" may dramatically affect patient outcomes. Neurocritical care providers should be mindful of geographic variation in local protocols when designing and evaluating quality improvement interventions and should aim to standardize prehospital care protocols.