Basilar Impression: A Systematic Review and Meta-Analysis of Clinical Features, Operative Strategies and Outcomes.

OBJECTIVE: Basilar Impression (BI) is a rare yet debilitating abnormality of the craniovertebral junction (CVJ), known to cause life-threatening medullary brainstem compression. Our study analyzes surgical approaches for BI and related outcomes. METHODS: A systematic review was conducted using PubMed, Google Scholar, and Web of Science electronic databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to critically assess primary articles examining BI. RESULTS: We analyzed 87 patients from 65 articles, mostly female (55.17%) with a mean age of 46.31 ± 17.94 years, commonly presenting with motor (59.77%) and sensory deficits (55.17%). Commonly employed procedures included posterior occipitocervical fusion (24.14%), anterior decompression (20.69%), and combined anterior decompression with posterior fusion (21.84%). Patients who underwent anterior approaches were found to be older (55.38 ± 17.67 vs. 45.49 ± 18.78 years, p < 0.05) and had a longer duration from symptom onset to surgery (57.39 ± 64.33 vs. 26.02 ± 29.60 months, p < 0.05) compared to posterior approaches. Our analysis revealed a significant association between a longer duration from symptom onset to surgery and an increased likelihood of undergoing odontoidectomy and decompression (OR: 1.02, 95% CI: 1.00-1.03, p < 0.05). Furthermore, after adjusting for all other covariates, a history of rheumatoid arthritis and the use of a posterior approach were significantly associated with an elevated risk of postoperative complications (p < 0.05). CONCLUSIONS: The treatment approach to complex CVJ disease should be tailored to the surgeon's experience and the nature of the compressive pathology.

Predictors of syrinx presentation and outcomes in pediatric Chiari malformation type I: a single institution experience of 218 consecutive syrinx patients.

PURPOSE: Chiari I malformation (CM-I) in pediatric patients can impose substantial neurologic and functional impairment. Additionally, the presence of syrinx is often a harbinger of clinical compromise, but little attention has been devoted to identifying features associated with syrinx development and the clinical impact of syrinx resolution. Therefore, this study aims to identify clinical and radiographic variables associated with preoperative syrinx presence and postoperative syrinx reduction in pediatric patients with CM-I and determine the relationship between postoperative syrinx reduction and clinical symptom improvement. METHODS: The authors performed a retrospective analysis of 435 consecutive pediatric patients who underwent surgical treatment of CM-I from 2001 to 2021 at a single tertiary pediatric medical center. All patients underwent pre- and postoperative MRI, and clinical and radiographic variables were recorded and subject to inferential analysis. RESULTS: Syrinx at presentation was independently associated with symptoms of spinal cord dysfunction at presentation (OR 2.17 (95% CI 1.05-4.48); p = 0.036), scoliosis (OR 5.33 (2.34-10.86); p = 0.001), and greater pB-C2 (posterior basion to C2 distance) measurement length (OR 1.14 (95% CI 1.01-1.30); p = 0.040). Syrinx at presentation was inversely associated with tussive headaches at presentation (OR 0.27 (95% CI 0.16-0.47); p = 0.001) and cranial nerve deficits at presentation (OR 0.49 (95% CI 0.26-0.92); p = 0.025). Postoperatively, patients with radiographic evidence of syrinx improvement had greater rates of symptom improvement (93.1% vs 82.1%; p = 0.049), better CCOS scores (15.4 vs 14.2; p = 0.001), and decreased rates of readmission (6.0% vs 25.0%, p = 0.002) and reoperation (0.5% vs 35.7%; p = 0.001). The difference in syrinx resolution was similar but not statistically significant (10.3% vs 16.7%; p = 0.251). AO joint anomaly (OR 0.20, 95% CI 0.04-0.95; p = 0.026) and foramen magnum diameter (OR 1.12, 95% CI 1.00-1.25; p = 0.049) were the only independent predictors of syrinx improvement, and surgical technique was the only predictor for syrinx resolution (OR 2.44, 95% CI 1.08-5.50; p = 0.031). Patients that underwent tonsil reduction surgery whose syrinx improved had a wider foramen magnum diameter than those whose did not improve (34.3 vs 31.7; p = 0.028). CONCLUSIONS: Radiographic syrinx improvement is associated with greater rates of symptom improvement and less readmissions and reoperations for CM-I. AO joint anomalies and narrower foramen magnums were independent risk factors for the lack of syrinx improvement. These novel insights will help guide preoperative patient counseling, pre- and intraoperative surgical decision-making, and postoperative clinical prognostication in the treatment of pediatric CM-I.

Age is Associated with Level of First-Time Anterior Cervical Discectomy and Fusion: An Ordinal Analysis of Factors Influencing Timing of Cervical Degeneration.

BACKGROUND: Symptomatic cervical spondylosis is often treated with anterior cervical discectomy and fusion (ACDF). However, few factors can predict which cervical level will degenerate and require intervention. This analysis evaluates preprocedural factors associated with level of first-time single-level ACDF. METHODS: We performed a retrospective analysis of patients who underwent single-level ACDF without prior history of spine surgery. Mann Whitney U-tests and Spearman rank-order correlation were performed for analyses of associations between variables of interest and ACDF level. Adjusted odds-ratios were calculated by proportional-odds logistic regression, with age, sex, body mass index, current tobacco use, history of neck trauma, preoperative radicular symptoms, and preoperative myelopathic symptoms as covariates. RESULTS: One hundred forty-one patients met inclusion criteria, and age demonstrated a negative correlation with ACDF level, such that younger patients tended to have ACDF performed at inferior subaxial levels (P = 0.0006, rho = -0.31, moderately strong relationship). Patients with preoperative radicular symptoms and myelopathic symptoms were more likely to have ACDF performed at inferior (P = 0.0001) and superior (P < 0.0001) levels, respectively. Patient sex, body mass index, current tobacco use, and history of neck trauma were not predictive of ACDF level. When adjusting for the above variables in a proportional-odds ordinal logistic regression model, a one-year increase in age conferred a 4% increase in the odds of requiring an ACDF at a given superior level compared to the adjacent inferior level. CONCLUSIONS: Age is correlated with level of first-time single level ACDF. Individual subaxial levels may have unique biomechanical properties that influence degeneration.

3D-Printed Spine Models for Planning Staged Minimally Invasive Transverse Process Resections for Bertolotti Syndrome: Technical Note.

Background: Three-dimensional (3D) printing has enabled numerous advances in spine surgery execution and education. However, few examples exist to outline how this technology can aid the performance of complex spine surgery using minimally invasive surgery (MIS) techniques. Therefore, we present a case that illustrates the benefits of 3D-printed spine model production before and after correction of a congenital lumbosacral anomaly using an MIS approach. Case Report: A 40-year-old woman with Bertolotti syndrome underwent a staged bilateral L6 MIS transverse process resection for the treatment of severe and progressive axial back pain which had repeatedly failed conservative management. 3D-printed spine models were used for pre- and post-operative surgical planning and patient counseling. Conclusion: 3D-printed spine models can aid in the planning of complex spine cases suited for an MIS approach.

Metastatic Infiltration of Nervous Tissue and Periosteal Nerve Sprouting in Multiple Myeloma-Induced Bone Pain in Mice and Human.

Multiple myeloma (MM) is a neoplasia of B plasma cells that often induces bone pain. However, the mechanisms underlying myeloma-induced bone pain (MIBP) are mostly unknown. Using a syngeneic MM mouse model, we show that periosteal nerve sprouting of calcitonin gene-related peptide (CGRP+) and growth associated protein 43 (GAP43+) fibers occurs concurrent to the onset of nociception and its blockade provides transient pain relief. MM patient samples also showed increased periosteal innervation. Mechanistically, we investigated MM induced gene expression changes in the dorsal root ganglia (DRG) innervating the MM-bearing bone of male mice and found alterations in pathways associated with cell cycle, immune response and neuronal signaling. The MM transcriptional signature was consistent with metastatic MM infiltration to the DRG, a never-before described feature of the disease that we further demonstrated histologically. In the DRG, MM cells caused loss of vascularization and neuronal injury, which may contribute to late-stage MIBP. Interestingly, the transcriptional signature of a MM patient was consistent with MM cell infiltration to the DRG. Overall, our results suggest that MM induces a plethora of peripheral nervous system alterations that may contribute to the failure of current analgesics and suggest neuroprotective drugs as appropriate strategies to treat early onset MIBP.SIGNIFICANCE STATEMENT Multiple myeloma (MM) is a painful bone marrow cancer that significantly impairs the quality of life of the patients. Analgesic therapies for myeloma-induced bone pain (MIBP) are limited and often ineffective, and the mechanisms of MIBP remain unknown. In this manuscript, we describe cancer-induced periosteal nerve sprouting in a mouse model of MIBP, where we also encounter metastasis to the dorsal root ganglia (DRG), a never-before described feature of the disease. Concomitant to myeloma infiltration, the lumbar DRGs presented blood vessel damage and transcriptional alterations, which may mediate MIBP. Explorative studies on human tissue support our preclinical findings. Understanding the mechanisms of MIBP is crucial to develop targeted analgesic with better efficacy and fewer side effects for this patient population.

Image-Guided Percutaneous Multilevel Pediculosynthesis for Treatment of Contiguous Pedicle Stress Fractures: Technical Case Report.

BACKGROUND: Nontraumatic pedicle fracture is uncommon, with sparsely described cases of conservative management versus surgical treatment by open fusion or percutaneous fixation. METHODS: We report the case of a 60-year-old woman with nontraumatic L4 and L5 pedicle fracture who developed additional pedicle fractures at L3 while undergoing conservative management in a brace. The patient underwent percutaneous pediculosynthesis with screw fixation without fusion at L3-5 bilaterally. RESULTS: The treatment led to fracture healing with good radiographic result and resolution of her symptoms. CONCLUSIONS: A trial of conservative management is typically warranted in most cases of nontraumatic pedicle fracture, but there is risk of refractory or progressive symptoms and subsequent fracture. Minimally invasive fixation is a viable surgical option that can be used in multilevel fractures.

Single Nucleotide Polymorphisms and Adolescent Idiopathic Scoliosis: A Systematic Review and Meta-Analysis of the Literature.

STUDY DESIGN: Meta-analysis. OBJECTIVE: To determine the single nucleotide polymorphisms (SNPs) that are related to adult idiopathic scoliosis. SUMMARY AND BACKGROUND DATA: Adolescent idiopathic scoliosis (AIS) is considered one of the most prevalent spinal diseases. Even though the cause of AIS is yet to be determined, family history and sex have shown conclusive associations. Multiple studies have indicated that AIS is more prevalent in families where at least one other first-degree relative is similarly affected, indicating a possible genetic etiology to AIS. MATERIALS AND METHODS: Articles were collected from 3 different search engines and then processed in 2 stages for final article selection for quantitative analysis. Five different genetic models were represented to show the association between the different SNPs and AIS. The Hardy-Weinberg equilibrium was examined using Fisher exact test, with significance set at P <0.05. The final analysis paper's quality was evaluated using the Newcastle Ottawa Scale. Kappa interrater agreement was calculated to evaluate the agreement between authors. RESULTS: The final analysis comprised 43 publications, 19412 cases, 22005 controls, and 25 distinct genes. LBX1 rs11190870 T>C and MATN-1 SNPs were associated with an increased risk of AIS in one or all of the 5 genetic models. IGF-1 , estrogen receptor alfa, and MTNR1B , SNPs were not associated with AIS in all 5 genetic models. Newcastle Ottawa Scale showed good quality for the selected articles. Cohen k = 0.741 and Kappa interrater agreement of 84% showed that the writers were in strong agreement. CONCLUSIONS: There seem to be associations between AIS and genetic SNP. Further larger studies should be conducted to validate the results.

RNA profiling of human dorsal root ganglia reveals sex differences in mechanisms promoting neuropathic pain.

Neuropathic pain is a leading cause of high-impact pain, is often disabling and is poorly managed by current therapeutics. Here we focused on a unique group of neuropathic pain patients undergoing thoracic vertebrectomy where the dorsal root ganglia is removed as part of the surgery allowing for molecular characterization and identification of mechanistic drivers of neuropathic pain independently of preclinical models. Our goal was to quantify whole transcriptome RNA abundances using RNA-seq in pain-associated human dorsal root ganglia from these patients, allowing comprehensive identification of molecular changes in these samples by contrasting them with non-pain-associated dorsal root ganglia. We sequenced 70 human dorsal root ganglia, and among these 50 met inclusion criteria for sufficient neuronal mRNA signal for downstream analysis. Our expression analysis revealed profound sex differences in differentially expressed genes including increase of IL1B, TNF, CXCL14 and OSM in male and CCL1, CCL21, PENK and TLR3 in female dorsal root ganglia associated with neuropathic pain. Coexpression modules revealed enrichment in members of JUN-FOS signalling in males and centromere protein coding genes in females. Neuro-immune signalling pathways revealed distinct cytokine signalling pathways associated with neuropathic pain in males (OSM, LIF, SOCS1) and females (CCL1, CCL19, CCL21). We validated cellular expression profiles of a subset of these findings using RNAscope in situ hybridization. Our findings give direct support for sex differences in underlying mechanisms of neuropathic pain in patient populations.

Stereo-EEG Evaluation and Surgical Treatment in Patients With Drug-Resistant Focal Epilepsy Associated With Nodular Heterotopia.

PURPOSE: Nodular heterotopia (NH) is a common cause of drug-resistant epilepsy. Only limited studies detail the treatment of NH with laser interstitial thermal therapy and none analyze the relation between epileptogenicity and NH location. METHODS: We retrospectively studied nine patients with drug-resistant epilepsy and NH who underwent stereoelectroencephalography and subsequent epilepsy surgery. Nodular heterotopia in the frontal lobes or along the bodies of the lateral ventricles was classified as anterior NH. Nodular heterotopia in the trigones, temporal or occipital horns, or temporal lobes was classified as posterior NH. Nodular heterotopia in both anterior and posterior locations was classified as diffuse NH. Interictal and ictal stereoelectroencephalography were analyzed, and patients were followed postoperatively to assess outcomes. RESULTS: Of the six patients who underwent nine laser interstitial thermal therapy procedures either in isolation or in combination with other surgical therapies, four patients were Engel Ia, one was Engel IIb, and one was Engel IIIa, with an average follow-up of 22.8 months. All patients with posterior NH had interictal epileptiform abnormalities and seizures originating from the posterior NH. None of the patients with anterior NH had epileptiform activity recorded from their NH. CONCLUSION: Laser interstitial thermal therapy alone or in combination with other surgical therapies is an effective treatment in those with drug-resistant epilepsy because of NH, even in those with extensive NH and broad seizure onset. We observed a trend suggesting that posterior NH are more likely to be epileptogenic compared with anterior NH and recommend that in patients with anterior NH, alternative epilepsy etiologies and stereoelectroencephalography implantation strategies be considered.

Development and Internal Validation of the Postoperative Analgesic Intake Needs Score: A Predictive Model for Post-Operative Narcotic Requirement after Spine Surgery.

STUDY DESIGN: Retrospective Cohort. OBJECTIVE: The aim of this study was to develop a clinical tool to pre-operatively risk-stratify patients undergoing spine surgery based on their likelihood to have high postoperative analgesic requirements. METHODS: A total of 1199 consecutive patients undergoing elective spine surgery over a 2-year period at a single center were included. Patients not requiring inpatient admission, those who received epidural analgesia, those who had two surgeries at separate sites under one anesthesia event, and those with a length of stay greater than 10 days were excluded. The remaining 860 patients were divided into a derivation and validation cohort. Pre-operative factors were collected by review of the electronic medical record. Total postoperative inpatient opioid intake requirements were converted into morphine milligram equivalents to standardize postoperative analgesic requirements. RESULTS: The postoperative analgesic intake needs (PAIN) score was developed after the following predictor variables were identified: age, race, history of depression/anxiety, smoking status, active pre-operative benzodiazepine use and pre-operative opioid use, and surgical type. Patients were risk-stratified based on their score with the high-risk group being more likely to have high opioid consumption postoperatively compared to the moderate and low-risk groups in both the derivation and validation cohorts. CONCLUSION: The PAIN Score is a pre-operative clinical tool for patients undergoing spine surgery to risk stratify them based on their likelihood for high analgesic requirements. The information can be used to individualize a multi-modal analgesic regimen rather than utilizing a "one-size fits all" approach.

Applying 3-Dimensional Printing and Modeling for Preoperative Reconstruction and Instrumentation Placement Planning in Complex Deformity Surgery.

BACKGROUND: Advances in three-dimensional (3D) printing technology have enabled the development of customized instrumentation and surgical training platforms. However, no existing studies have assessed how patient-specific 3D-printed spine models can facilitate patient education and operative planning in complex spinal deformity correction. OBJECTIVE: To present a cost-effective technique for constructing personalized 3D-printed spine models for patients with severe spinal deformities and to outline how these models can promote informed consent, trainee education, and planning for instrumentation placement and alignment correction. METHODS: We present 2 patients who underwent surgical correction of progressive thoracolumbar deformities. Full-scale 3D-printed models of each patient's spine were produced preoperatively and used during clinic evaluations, surgical planning, and as intraoperative references. RESULTS: Each model took 9 days to build and required less than 60 US dollars of material costs. Both patients were treated with a posterior approach and contiguous multilevel osteotomies. Postoperatively, their alignment parameters and neurological deficits improved. CONCLUSION: Personalized 3D-printed spine models can aid in patient education, surgical training, visualization, and correction of complex spinal deformities.

Endoscopic Endonasal versus Transcranial Optic Canal Decompression: A Morphometric, Cadaveric Study.

Introduction Decompression of the optic nerve within the optic canal is indicated for compressive visual decline. The two most common approaches utilized for optic canal decompression are a medial approach with an endoscopic endonasal approach and a lateral approach with a craniotomy. Our study is a cadaveric anatomical study comparing the length and circumference of the orbit decompressed via an endoscopic endonasal approach versus a frontotemporal craniotomy. Methods Five cadaveric specimens were utilized. Predissection computed tomography (CT) scans were performed on each specimen. On each specimen, a standard frontotemporal craniotomy with anterior clinoidectomy and superolateral orbital decompression was performed on one side and an endoscopic endonasal approach with medial wall decompression was performed on the contralateral side. Post-dissection CT scans were performed. An independent radiologist provided measurements of the length (mm) and circumference (degrees) of optic canal decompression bilaterally. Results The mean length of optic canal decompression for open and endoscopic approach was 13 mm (range 12-15 mm) and 12.4 mm (range 10-16 mm), respectively. The mean circumference of decompression for open and endoscopic approaches was 252.8 degrees (range 205-280 degrees) and 124.6 degrees (range 100-163 degrees), respectively. Conclusion The endoscopic endonasal and the transcranial approaches provide a similar length of optic canal decompression, but the transcranial approach leads to greater circumferential decompression. The endoscopic endonasal approach has the benefit of being minimally invasive, though. Ultimately, the surgical approach decision should be based on the location of the pathology and the surgeon's comfort.

Imaging as a Pain Biomarker.

In recent years, the hunt for objective biomarkers in chronic pain has intensified, as interest has grown in precision medicine techniques, and the global opioid crisis has underscored the need to accelerate the pace of pain research. A growing body of neuroimaging literature suggests that chronic pain is associated with various alterations in regional brain areas as well as whole-brain networks, which may represent unique radiological pain signatures or biomarkers to guide diagnosis, response, and treatment. Here, we provide a comprehensive and updated literature review on investigative efforts to identify neuroimaging biomarkers for pain.

Transfusion Guidelines in Brain Tumor Surgery: A Systematic Review and Critical Summary of Currently Available Evidence.

OBJECTIVE: Red blood cell (RBC) transfusion is commonly indicated in brain tumor surgery due to risk of blood loss. Current transfusion guidelines are based on evidence derived from critically ill patients and may not be optimal for brain tumor surgeries. Our study is the first to synthesize available evidence to suggest RBC transfusion thresholds in brain tumor patients undergoing surgery. METHODS: A systematic review was conducted using PubMed, EMBASE, and Google Scholar databases in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines to critically assess RBC transfusion thresholds in adult patients with brain tumors and complications secondary to transfusion following blood loss in the operating room or perioperative period. RESULTS: Seven articles meeting our search criteria were reviewed. Brain tumor patients who received blood transfusions were older, had greater rates of American Society of Anesthesiologists class 3 or 4, and presented with increased number of comorbidities including diabetes, hypertension, and cardiovascular diseases. In addition, transfused patients had a prolonged surgical time. Transfusions were associated with multiple postoperative major and minor complications, including longer hospital length of stay, increased return to the operating room, and elevated 30-day mortality. Analysis of transfusion thresholds showed that a restrictive hemoglobin threshold of 8 g/dL is safe in patients, as evidenced by a reduction in length of stay, mortality, and complications (level C class IIa). CONCLUSIONS: A restrictive Hb threshold of 8 g/dL appears to be safe and minimizes potential complications of transfusion in brain tumor patients.

Relative Citation Ratios of Global Surgery, Obstetrics, Trauma, and Anesthesia: Implications and Lessons for Global Neurosurgery.

BACKGROUND: The National Institutes of Health has developed a new metric, the Relative Citation Ratio (RCR), to assess the impact of research articles and compare academic productivity across different fields. Global surgery, obstetrics, trauma, and anesthesia (SOTA) are young and increasingly popular fields attracting researchers and funding. This study analyzed the RCR of global neurosurgery; compared it with other global SOTA specialties; and discussed the implications for researchers, academic institutions, and aspiring global neurosurgeons. METHODS: Metadata were downloaded from the National Institutes of Health RCR website for 12 established global surgery specialties, including global neurosurgery. The authors performed descriptive and bivariable inferential analyses to evaluate differences in the number of total publications, median number of citations per year, and median RCR for each specialty for which data were available. RESULTS: Global pediatric surgery had the highest median citations per year (2.00, interquartile range: 0.63-3.50; P = 0.048) and median relative citation ratio (1.36, interquartile range: 0.33-1.95; P = 0.693). In comparison, global neurosurgery articles had 0.20 median citations per year (IQR: 0-1.5) and 0.54 (IQR: 0.12-1.30) median relative citations. The median expected citations per year for all SOTA articles was 1.77. CONCLUSIONS: We observed strong development of global neurosurgery and SOTA research. Overall, the use of the RCR will facilitate standardized interfield and intrafield academic productivity comparisons. Based on the results presented in this study, global neurosurgery is a promising career route for young and aspiring academic neurosurgeons.

Percutaneous screw fixation versus open fusion for the treatment of traumatic thoracolumbar fractures: A retrospective case series of 185 Patients with a single-level spinal column injury.

STUDY DESIGN: Retrospective Single-Center Review of Data at a Level 1 Trauma Center. OBJECTIVE: Compare deformity correction and surgical outcomes of percutaneous instrumentation and open fusion in traumatic thoracolumbar fractures. METHODS: In our retrospective study, all patients undergoing elective spine surgery for TL fractures at a Level 1 trauma center between 2000 and 2017 were reviewed. Patients who underwent percutaneous fixation were given the option of hardware removal after the fracture had healed. RESULTS: A total of 185 patients were included in the study, with 109 treated with an open fusion, and 76 with percutaneous fixation. Twenty-five patients in the latter group had the instrumentation removed after the fracture had healed. None of them required reoperation. In the open fusion group 54.1% of patients required a decompressive laminectomy. Percutaneous fixation patients had a shorter operative time (98.3 min vs 214 min, p < 0.0001), shorter length of stay (9.8 days vs 13.5 days, p = 0.04), and less blood loss (68.4 cc vs 691 cc, p < 0.001). They also had a better correction of their traumatic kyphosis after surgery (p = 0.005). CONCLUSION: Percutaneous fixation is a valuable option for the treatment of TL fractures in cases without evidence of neural compression. It is still unclear whether hardware removal helps prevent adjacent segment degeneration. Percutaneous fixation could allow for better reduction of the fracture with improvement of postoperative alignment.

Trends in Racial and Ethnic Representation Among Neurosurgery Applicants and Residents: A Comparative Analysis of Procedural Specialties.

BACKGROUND: Diversity, equity, and inclusion within the healthcare workforce are conducive to providing culturally competent care. However, few existing studies have assessed the level of racial and ethnic diversity among resident physicians and residency applicants. Our objective was to provide a comparative analysis of the trends in racial and ethnic representation within different subspecialties in medicine. METHODS: Using data from the American Association of Medical Colleges and the Journal of the American Medical Association, we evaluated the racial and ethnic identification of residency applicants and current residents in 9 procedural-focused specialties from 2005 to 2019 and performed a descriptive analysis to compare the different levels of racial and ethnic diversity in these specialties. RESULTS: Among the specialties analyzed during the study period, neurosurgery had the greatest magnitude of differences between Black/African-American residency applicants and current residents. The percentage of Black/African-American applicants was 92% greater than that of Black/African-American residents (10% of applicants vs. 5.2% of residents). In contrast, the percentage of White neurosurgery residents was 17.6% greater than that of White neurosurgery applicants (53.9% of applicants vs. 63.4% of residents). Similar trends were noted in all the specialties evaluated. Obstetrics and gynecology demonstrated the least disparity between Black/African-American applicants and residents (13.7% of applicants vs. 10.2% of residents; 35.4% difference). Hispanic and Asian representation varied widely between specialties. CONCLUSIONS: Among the surveyed specialties, neurosurgery demonstrated the greatest disparity between the percentage of Black/African-American residency applicants and current residents. To further drive progress in this domain, we advocate for a series of initiatives designed to increase underrepresented minority participation in neurosurgery practice and scholarship.