Comparison of Postoperative Seizures Between Burr-Hole Evacuation and Craniotomy in Patients With Nonacute Subdural Hematomas: A Bi-Institutional Propensity Score-Matched Analysis.

BACKGROUND AND OBJECTIVES: Postoperative seizures are a common complication after surgical drainage of nonacute chronic subdural hematomas (SDHs). The literature increasingly supports the use of prophylactic antiepileptic drugs for craniotomy, a procedure that is often associated with larger collections and worse clinical status at admission. This study aimed to compare the incidence of postoperative seizures in patients treated with burr-hole drainage and those treated with craniotomy through propensity score matching (PSM). METHODS: A retrospective cohort analysis was conducted on patients with surgical drainage of nonacute SDHs (burr-holes and craniotomies) between January 2017 to December 2021 at 2 academic institutions in the United States. PSM was performed by controlling for age, subdural thickness, subacute component, and preoperative Glasgow Coma Scale. Seizure rates and accompanying abnormalities on electroencephalographic tracing were evaluated postmatching. RESULTS: A total of 467 patients with 510 nonacute SDHs underwent 474 procedures, with 242 burr-hole evacuations (51.0%) and 232 craniotomies (49.0%). PSM resulted in 62 matched pairs. After matching, univariate analysis revealed that burr-hole evacuations exhibited lower rates of seizures (1.6% vs 11.3%; P = .03) and abnormal electroencephalographic findings (0.0% vs 4.8%; P = .03) compared with craniotomies. No significant differences were observed in postoperative Glasgow Coma Scale (P = .77) and length of hospital stay (P = .61). CONCLUSION: Burr-hole evacuation demonstrated significantly lower seizure rates than craniotomy using a propensity score-matched analysis controlling for significant variables.

Importance of Multispecialty Coordination of Care in an Electroconvulsive Therapy Patient With Musculoskeletal, Neurological, and Vascular Injuries: A Case Report.

ABSTRACT: Electroconvulsive therapy (ECT) is considered an effective therapy for patients suffering from severe, life-threatening, intractable depression. This treatment modality delivers controlled electrical currents (typically no more than 100 J) under general anesthesia to induce seizure. Although generally considered to have a high safety profile, physiological changes induced during the ictal phase of ECT, such as elevation in blood pressure and intracranial pressure, impose additional risks to patients with concomitant cardiovascular or cerebrovascular conditions. We describe the successful use of ECT in a unique case complicated by a combination of acute vertebral artery dissection, traumatic intracerebral hemorrhage, and cervical spine injury sustained from a suicide attempt by intentional motor vehicle collision. Although ECT can be safely administered in the presence of recent vertebral artery dissection and traumatic intraparenchymal hemorrhage, an emphasis on multispecialty coordination is crucial to monitor and reduce the risk of elevated blood pressure and further cervical spine injury.

Establishing connectivity through microdissections of midbrain stimulation-related neural circuits.

Comprehensive understanding of the neural circuits involving the ventral tegmental area is essential for elucidating the anatomo-functional mechanisms governing human behaviour as well as the therapeutic and adverse effects of deep brain stimulation for neuropsychiatric diseases. While the ventral tegmental area has been successfully targeted with deep brain stimulation for different neuropsychiatric diseases, the axonal connectivity of the region has not been fully understood. Here using fiber micro-dissections in human cadaveric hemispheres, population-based high-definition fiber tractography, and previously reported deep brain stimulation hotspots, we find that the ventral tegmental area participates in an intricate network involving the serotonergic pontine nuclei, basal ganglia, limbic system, basal forebrain, and prefrontal cortex, which is implicated in the treatment of obsessive-compulsive disorder, major depressive disorder, Alzheimer's disease, cluster headaches, and aggressive behaviors.

Metal-Solvent Complex Formation at the Surface of InP Colloidal Quantum Dots.

The surface chemistry of colloidal semiconductor nanocrystals (QDs) profoundly influences their physical and chemical attributes. The insulating organic shell ensuring colloidal stability impedes charge transfer, thus limiting optoelectronic applications. Exchanging these ligands with shorter inorganic ones enhances charge mobility and stability, which is pivotal for using these materials as active layers for LEDs, photodetectors, and transistors. Among those, InP QDs also serve as a model for surface chemistry investigations. This study focuses on group III metal salts as inorganic ligands for InP QDs. We explored the ligand exchange mechanism when metal halide, nitrate, and perchlorate salts of group III (Al, In Ga), common Lewis acids, are used as ligands for the conductive inks. Moreover, we compared the exchange mechanism for two starting model systems: InP QDs capped with myristate and oleylamine as X- and L-type native organic ligands, respectively. We found that all metal halide, nitrate, and perchlorate salts dissolved in polar solvents (such as n-methylformamide, dimethylformamide, dimethyl sulfoxide, H2O) with various polarity formed metal-solvent complex cations [M(Solvent)6]3+ (e.g., [Al(MFA)6]3+, [Ga(MFA)6]3+, [In(MFA)6]3+), which passivated the surface of InP QDs after the removal of the initial organic ligand. All metal halide capped InP/[M(Solvent)6]3+ QDs show excellent colloidal stability in polar solvents with high dielectric constant even after 6 months in concentrations up to 74 mg/mL. Our findings demonstrate the dominance of dissociation-complexation mechanisms in polar solvents, ensuring colloidal stability. This comprehensive understanding of InP QD surface chemistry paves the way for exploring more complex QD systems such as InAs and InSb QDs.

Vitamin D Receptor Antagonist MeTC7 Inhibits PD-L1.

Small-molecule inhibitors of PD-L1 are postulated to control immune evasion in tumors similar to antibodies that target the PD-L1/PD-1 immune checkpoint axis. However, the identity of targetable PD-L1 inducers is required to develop small-molecule PD-L1 inhibitors. In this study, using chromatin immunoprecipitation (ChIP) assay and siRNA, we demonstrate that vitamin D/VDR regulates PD-L1 expression in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) cells. We have examined whether a VDR antagonist, MeTC7, can inhibit PD-L1. To ensure that MeTC7 inhibits VDR/PD-L1 without off-target effects, we examined competitive inhibition of VDR by MeTC7, utilizing ligand-dependent dimerization of VDR-RXR, RXR-RXR, and VDR-coactivators in a mammalian 2-hybrid (M2H) assay. MeTC7 inhibits VDR selectively, suppresses PD-L1 expression sparing PD-L2, and inhibits the cell viability, clonogenicity, and xenograft growth of AML cells. MeTC7 blocks AML/mesenchymal stem cells (MSCs) adhesion and increases the efferocytotic efficiency of THP-1 AML cells. Additionally, utilizing a syngeneic colorectal cancer model in which VDR/PD-L1 co-upregulation occurs in vivo under radiation therapy (RT), MeTC7 inhibits PD-L1 and enhances intra-tumoral CD8+T cells expressing lymphoid activation antigen-CD69. Taken together, MeTC7 is a promising small-molecule inhibitor of PD-L1 with clinical potential.

Model-based image updating in deep brain stimulation with assimilation of deep brain sparse data.

BACKGROUND: Accuracy of electrode placement for deep brain stimulation (DBS) is critical to achieving desired surgical outcomes and impacts the efficacy of treating neurodegenerative diseases. Intraoperative brain shift degrades the accuracy of surgical navigation based on preoperative images. PURPOSE: We extended a model-based image updating scheme to address intraoperative brain shift in DBS surgery and improved its accuracy in deep brain. METHODS: We evaluated 10 patients, retrospectively, who underwent bilateral DBS surgery and classified them into groups of large and small deformation based on a 2 mm subsurface movement threshold and brain shift index of 5%. In each case, sparse brain deformation data were used to estimate whole brain displacements and deform preoperative CT (preCT) to generate updated CT (uCT). Accuracy of uCT was assessed using target registration errors (TREs) at the Anterior Commissure (AC), Posterior Commissure (PC), and four calcification points in the sub-ventricular area by comparing their locations in uCT with their ground truth counterparts in postoperative CT (postCT). RESULTS: In the large deformation group, TREs were reduced from 2.5 mm in preCT to 1.2 mm in uCT (53% compensation); in the small deformation group, errors were reduced from 1.25 to 0.74 mm (41%). Average reduction of TREs at AC, PC and pineal gland were significant, statistically (p ⩽ 0.01). CONCLUSIONS: With more rigorous validation of model results, this study confirms the feasibility of improving the accuracy of model-based image updating in compensating for intraoperative brain shift during DBS procedures by assimilating deep brain sparse data.

First demonstration of a novel nerve-targeting fluorophore in a cohort of ex vivo human tissues.

Iatrogenic nerve injury is a common complication across all surgical specialties. Better nerve visualization and identification during surgery will improve outcomes and reduce nerve injuries. The Gibbs Laboratory at Oregon Health and Science University has developed a library of near-infrared, nerve-specific fluorophores to highlight nerves intraoperatively and aid surgeons in nerve identification and visualization; the current lead agent is LGW16-03. Prior to this study, testing of LGW16-03 was restricted to animal models; therefore, it was unknown how LGW16-03 performs in human tissue. To advance LGW16-03 to clinic, we sought to test this current lead agent in ex vivo human tissues from a cohort of patients and determine if the route of administration affects LGW16-03 fluorescence contrast between nerves and adjacent background tissues (muscle and adipose). LGW16-03 was applied to ex vivo human tissue from lower limb amputations via two strategies: (1) systemic administration of the fluorophore using our first-in-kind model for fluorophore testing, and (2) topical application of the fluorophore. Results showed no statistical difference between topical and systemic administration. However, in vivo human validation of these findings is required.

United Network for Organ Sharing (UNOS) Database Analysis of Factors Associated With Kidney Transplant Time on Waiting List.

INTRODUCTION:  In the United States (U.S.), African Americans and other minority groups have longer wait times for kidney transplantation than Caucasians. To date, many studies analyzing time spent on the waitlist for each race/ethnicity have been done. However, there are few to no studies examining waitlist time after the 2019 policy changes to the geographic distribution of donated kidneys. METHODS: Data collected from the National Organ Procurement and Transplantation Network database were used to analyze associations between race and time spent on the waitlist for a kidney transplant in the U.S. Additional sub-categorical data were analyzed to determine further associations and potential covariates, such as gender, age, citizenship, primary source of payment, region of transplant center, BMI, Kidney Donor Profile Index (KDPI), renal diagnosis, and presence/type of diabetes. Data were analyzed using odds ratios and validated by Bonferroni-Holm's corrected chi-square tests at confidence intervals of 95% to determine if there are statistically significant differences between transplant time spent on the waitlist and ethnicity, as well as age, diagnosis category, region of transplant center, and KDPI. RESULTS: Statistically significant increased odds of remaining on the transplant list at two years existed for all non-white races/ethnicities, except those identifying as multiracial. Asian American candidates had the greatest odds of remaining on the waitlist greater than two years in comparison to white candidates: 1.51 times that of a patient categorized as white (odds ratio [OR] 1.51, confidence interval [CI] 1.44-1.57). African American/Black, (OR 1.38, CI 1.34-1.43) Pacific Islander (OR 1.38, CI 1.17-1.63), Hispanic candidates (OR 1.37, CI 1.32-1.41), and American Indian or Native Alaskan candidates (OR 1.23, CI 1.12-1.46) also had increased odds of remaining on the transplant waitlist greater than two years compared to white candidates. DISCUSSION: In this study, ethnic disparities persisted as a barrier for non-white individuals receiving treatment for end-stage kidney disease, specifically in the context of time spent on the waitlist for a kidney transplant. Further research is needed regarding the causes of these disparities in time spent on the waitlist, such as cultural restrictions in organ donation, racial differences in parameters for organ match, and institutionalized racism in health care practitioners.

The New England Neurosurgical Society: growth and evolution over 70 years.

The New England Neurosurgical Society (NENS) was founded in 1951 under the leadership of its first President (Dr. William Beecher Scoville) and Secretary-Treasurer (Dr. Henry Thomas Ballantine). The purpose of creating the NENS was to unite local neurosurgeons in the New England area; it was one of the first regional neurosurgical societies in America. Although regional neurosurgical societies are important supplements to national organizations, they have often been overshadowed in the available literature. Now in its 70th year, the NENS continues to serve as a platform to represent the needs of New England neurosurgeons, foster connections and networks with colleagues, and provide research and educational opportunities for trainees. Additionally, regional societies enable discussion of issues uniquely relevant to the region, improve referral patterns, and allow for easier attendance with geographic proximity. In this paper, the authors describe the history of the NENS and provide a roadmap for its future. The first section portrays the founders who led the first meetings and establishment of the NENS. The second section describes the early years of the NENS and profiles key leaders. The third section discusses subsequent neurosurgeons who steered the NENS and partnerships with other societies. In the fourth section, the modern era of the NENS and its current activities are highlighted.

Race and Ethnicity and the Utilization of Security Responses in a Hospital Setting.

BACKGROUND: Security emergency responses (SERs) are utilized by hospitals to ensure the safety of patients and staff but can cause unintended morbidity. The presence of racial and ethnic inequities in SER utilization has not been clearly elucidated. OBJECTIVE: To determine whether Black and Hispanic patients experience higher rates of SER and physical restraints in a non-psychiatric inpatient setting. DESIGN: Retrospective cohort study. PARTICIPANTS: All patients discharged from September 2018 through December 2019. EXPOSURE: Race and ethnicity, as reported by patients at time of registration. MAIN OUTCOMES: The primary outcome was whether a SER was called on a patient. The secondary outcome was the incidence of physical restraints among patients who experienced a SER. KEY RESULTS: Among 24,212 patients, 18,755 (77.5%) patients identified as white, 2,346 (9.7%) as Black, and 2,425 (10.0%) identified with another race. Among all patients, 1,827 (7.6%) identified as Hispanic and 21,554 (89.0%) as non-Hispanic. Sixty-six (2.8%) Black patients had a SER activated during their first admission, compared to 295 (1.6%) white patients. In a Firth logit multivariable model, Black patients had higher adjusted odds of a SER than white patients (adjusted odds ratio (aOR) 1.37 [95% confidence interval: 1.02, 1.81], p = 0.037). Hispanic patients did not have higher odds of having a SER called than non-Hispanic patients. In a Poisson multivariable model among patients who had a SER called, race and ethnicity were not found to be significant predictors of restraint. CONCLUSION: Black patients had higher odds of a SER compared to white patients. No significant differences were found between Hispanic and non-Hispanic patients. Future efforts should focus on assessing the generalizability of these findings, the underlying mechanisms driving these inequities, and effective interventions to address them.

Functional Reorganization of the Mesial Frontal Premotor Cortex in Patients With Supplementary Motor Area Seizures.

BACKGROUND: Direct cortical stimulation of the mesial frontal premotor cortex, including the supplementary motor area (SMA), is challenging in humans. Limited access to these brain regions impedes understanding of human premotor cortex functional organization and somatotopy. OBJECTIVE: To test whether seizure onset within the SMA was associated with functional remapping of mesial frontal premotor areas in a cohort of patients with epilepsy who underwent awake brain mapping after implantation of interhemispheric subdural electrodes. METHODS: Stimulation trials from 646 interhemispheric subdural electrodes were analyzed and compared between patients who had seizure onset in the SMA (n = 13) vs patients who had seizure onset outside of the SMA (n = 12). 1:1 matching with replacement between SMA and non-SMA data sets was used to ensure similar spatial distribution of electrodes. Centroids and 95% confidence regions were computed for clustered head, trunk, upper extremity, lower extremity, and vision responses. A generalized linear mixed-effects model was used to test for significant differences in the resulting functional maps. Clinical, radiographic, and histopathologic data were reviewed. RESULTS: After analyzing direct cortical stimulation trials from interhemispheric electrodes, we found significant displacement of the head and trunk responses in SMA compared with non-SMA patients ( P < .01 for both). These differences remained significant after accounting for structural lesions, preexisting motor deficits, and seizure outcome. CONCLUSION: The somatotopy of the mesial frontal premotor regions is significantly altered in patients who have SMA-onset seizures compared with patients who have seizure onset outside of the SMA, suggesting that functional remapping can occur in these brain regions.

Digital Spatial Profiling for Characterization of the Microenvironment in Adult-Type Diffusely Infiltrating Glioma.

Diffusely infiltrating gliomas are associated with high morbidity and mortality due to the infiltrative nature of tumor spread. They are morphologically complex tumors, with a high degree of proteomic variability across both the tumor itself and its heterogenous microenvironment. The malignant potential of these tumors is enhanced by the dysregulation of proteins involved in several key pathways, including processes that maintain cellular stability and preserve the structural integrity of the microenvironment. Although there have been numerous bulk and single-cell glioma analyses, there is a relative paucity of spatial stratification of these proteomic data. Understanding differences in spatial distribution of tumorigenic factors and immune cell populations between the intrinsic tumor, invasive edge, and microenvironment offers valuable insight into the mechanisms underlying tumor proliferation and propagation. Digital spatial profiling (DSP) represents a powerful technology that can form the foundation for these important multilayer analyses. DSP is a method that efficiently quantifies protein expression within user-specified spatial regions in a tissue specimen. DSP is ideal for studying the differential expression of multiple proteins within and across regions of distinction, enabling multiple levels of quantitative and qualitative analysis. The DSP protocol is systematic and user-friendly, allowing for customized spatial analysis of proteomic data. In this experiment, tissue microarrays are constructed from archived glioblastoma core biopsies. Next, a panel of antibodies is selected, targeting proteins of interest within the sample. The antibodies, which are preconjugated to UV-photocleavable DNA oligonucleotides, are then incubated with the tissue sample overnight. Under fluorescence microscopy visualization of the antibodies, regions of interest (ROIs) within which to quantify protein expression are defined with the samples. UV light is then directed at each ROI, cleaving the DNA oligonucleotides. The oligonucleotides are microaspirated and counted within each ROI, quantifying the corresponding protein on a spatial basis.

Emerging drugs for the treatment of major depressive disorder.

INTRODUCTION: Major depressive disorder (MDD) continues to be one of the highest contributors to disease burden and years lived with disability in the world. Current existing treatments have been associated with intolerable side effects, long onset of action and suboptimal remission rates. Newer agents are being developed that will be reviewed here, such as glutamate and gamma-aminobutyric acid (GABA) and the reinvigorated testing of psychedelic drugs. This review will summarize the target mechanisms of the newer ADTs currently in development and available on the market. AREAS COVERED: It briefly covers the existing agents for MDD and treatment-resistant depression (TRD) and the need for new agents with higher efficacy. Therapeutic agents currently in Phase II or later clinical trials are listed and discussed, based on a thorough review of the US National Institutes of Health clinicaltrials.gov index and a search of the Informa Pharmaprojects database. Compounds of interest are grouped into scientific rationale and include atypical antipsychotics, GABA positive allosteric modulators, glutamatergic agents, opioids, orexin 2 receptor antagonists, and psychedelics. EXPERT OPINION: New therapeutic agents currently in development are promising, with a more rapid onset of action and the ability to augment and treat TRD.

PTEN Regulates Dendritic Arborization by Decreasing Microtubule Polymerization Rate.

Phosphatase and tensin homolog (PTEN) is a major negative regulator of the phosphatidylinositol-3-kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR) pathway. Loss-of-function mutations in PTEN have been found in a subset of patients with macrocephaly and autism spectrum disorder (ASD). PTEN loss in neurons leads to somal hypertrophy, aberrant migration, dendritic overgrowth, increased spine density, and hyperactivity of neuronal circuits. These neuronal overgrowth phenotypes are present on Pten knock-out (KO) and reconstitution with autism-associated point mutations. The mechanism underlying dendritic overgrowth in Pten deficient neurons is unclear. In this study, we examined how Pten loss impacts microtubule (MT) dynamics in both sexes using retroviral infection and transfection strategies to manipulate PTEN expression and tag the plus-end MT binding protein, end-binding protein 3 (EB3). We found Pten KO neurons sprout more new processes over time compared with wild-type (WT) neurons. We also found an increase in MT polymerization rate in Pten KO dendritic growth cones. Reducing MT polymerization rate to the WT level was sufficient to reduce dendritic overgrowth in Pten KO neurons in vitro and in vivo Finally, we found that rescue of dendritic overgrowth via inhibition of MT polymerization was sufficient to improve the performance of Pten KO mice in a spatial memory task. Taken together, our data suggests that one factor underlying PTEN loss dependent dendritic overgrowth is increased MT polymerization. This opens the possibility for an intersectional approach targeting MT polymerization and mTOR with low doses of inhibitors to achieve therapeutic gains with minimal side effects in pathologies associated with loss of neuronal PTEN function.SIGNIFICANCE STATEMENT Loss of Pten function because of genetic deletion or expression of mutations associated with autism spectrum disorder (ASD), results in overgrowth of neurons including increased total dendritic length and branching. We have discovered that this overgrowth is accompanied by increased rate of microtubule (MT) polymerization. The increased polymerization rate is insensitive to acute inhibition of mechanistic target of rapamycin (mTOR)C1 or protein synthesis. Direct pharmacological inhibition of MT polymerization can slow the polymerization rate in Pten knock-out (KO) neurons to rates seen in wild-type (WT) neurons. Correction of the MT polymerization rate rescues increased total dendritic arborization and spatial memory. Our studies suggest that phosphatase and tensin homolog (PTEN) inhibits dendritic growth through parallel regulation of protein synthesis and cytoskeletal polymerization.

General Method to Increase Carboxylic Acid Content on Nanodiamonds.

Carboxylic acid is a commonly utilized functional group for covalent surface conjugation of carbon nanoparticles that is typically generated by acid oxidation. However, acid oxidation generates additional oxygen containing groups, including epoxides, ketones, aldehydes, lactones, and alcohols. We present a method to specifically enrich the carboxylic acid content on fluorescent nanodiamond (FND) surfaces. Lithium aluminum hydride is used to reduce oxygen containing surface groups to alcohols. The alcohols are then converted to carboxylic acids through a rhodium (II) acetate catalyzed carbene insertion reaction with tert-butyl diazoacetate and subsequent ester cleavage with trifluoroacetic acid. This carboxylic acid enrichment process significantly enhanced nanodiamond homogeneity and improved the efficiency of functionalizing the FND surface. Biotin functionalized fluorescent nanodiamonds were demonstrated to be robust and stable single-molecule fluorescence and optical trapping probes.

Association between interhospital transfer and increased in-hospital mortality in patients with spinal epidural abscesses.

BACKGROUND CONTEXT: Spinal epidural abscess (SEA) is an uncommon yet serious infection, associated with significant morbidity and mortality. Patients diagnosed with SEA often require surgical interventions or critical care services that are not available at community hospitals and are therefore transferred to tertiary care centers. Little is known about the effects of interhospital transfer on acute outcomes for patients with SEA. PURPOSE: To study the effects of interhospital transfer on acute outcomes for patients with SEA. STUDY DESIGN: Cross sectional analysis using the 2009 to 2017 National Inpatient Sample (NIS). PATIENT SAMPLE: Using the 2009 to 2017 NIS, we identified cases of SEA using ICD, Ninth, or Tenth Revision diagnosis codes 324.1 & G06.1. OUTCOME MEASURES: Our primary endpoint was in hospital mortality. METHODS: The association between interhospital transfer and inpatient mortality was assessed using multivariable logistic regression to adjust for potential covariates. Patient and hospital factors associated with interhospital transfer were assessed in a secondary analysis. RESULTS: A total of 21.5% of patient with SEA were treated after transfer from another hospital. After adjusting for covariates, those who presented after transfer had higher odds of death during hospitalization (OR: 1.51, 95% CI 1.27-1.78, p<.001). Transferred patients were significantly more likely to live in rural communities (11.4 % vs. 5.3 % for nontransferred patients). CONCLUSIONS: Interhospital transfer, which occurred more frequently in patients from rural hospitals, was associated with death even after controlling for disease severity. Addressing healthcare delivery disparities across the US, including across the rural-urban spectrum, will require better understanding of the observed increased mortality of interhospital transfer as a preventable source of in-hospital mortality for SEA.

Understanding secondary overtriage for neurosurgical patients in a rural tertiary care setting.

OBJECTIVE: Excessive interfacility transfer to a tertiary care facility of minimally injured patients for subspecialty evaluation leads to overuse of resources and is referred to as secondary overtriage (SO). Little is known regarding the epidemiology of SO in rural settings, particularly for patients with a mild head injury who may be safely managed without admission to level I trauma centers. METHODS: In order to determine the rate of SO for neurosurgical patients with Glasgow Coma Scale (GCS) of 13-15 referred to a rural level 1 trauma center, we conducted a retrospective chart review of 224 patients evaluated for potential transfer to Dartmouth-Hitchcock Medical Center from January 1, 2014 through December 31, 2014. SO was defined as any admission where a patient was transferred from an outside facility, had a length of stay shorter than 48 h, did not require neurosurgical intervention, and was alive at the time of discharge. RESULTS: Of the 224 patients evaluated, 163 patients were transferred. Of the 163 patients included in this study, 43 (26.4%) met criteria for SO, 59 (36.2%) patients met criteria for intervention, and 61 (37.2%) patients met criteria for observation. CONCLUSIONS: Approximately a quarter of the total patients who are transferred to a rural level I trauma center for neurosurgical evaluation are minimally injured, do not require neurosurgical intervention, and are discharged within 48 h of presentation. Management at their referring facility with remote neurosurgical consultation is likely safe in this population. Understanding the rate of SO in neurosurgical patients and risk factors present in this group can better guide future transfer policies at rural medical centers.