Correction: The leptomeninges as a critical organ for normal CNS development and function: First patient and public involved systematic review of arachnoiditis (chronic meningitis).

[This corrects the article DOI: 10.1371/journal.pone.0274634.].

Histologic Assessment of Lumbosacral Transitional Vertebrae Pseudoarticulation as a Source of Pain in Bertolotti Syndrome.

BACKGROUND: Bertolotti syndrome (BS) is characterized by chronic pain and functional impairment associated with lumbosacral transitional vertebrae (LSTVs). The study aimed to investigate the histologic characteristics of the pseudoarticulation between the enlarged transverse process and sacrum seen in Castellvi 2a LSTV and explore the involvement of nervous tissue in pain generation. METHODS: Immunohistochemical analysis using S100 protein staining was performed to assess the presence of nerve tissue. RESULTS: These changes included fibrillation, chondrocyte cloning, alterations in the proteoglycan matrix, and focal chondrocyte necrosis. Notably, no nerve tissue was observed in any of the specimens, as confirmed by negative S100 protein staining. CONCLUSIONS: The study findings suggest that nerve tissue is not involved in the nociceptive mechanisms underlying pain in BS. The histologic similarities between the pseudoarticulation and osteoarthritic joints indicate that pseudoarticulation itself may be a significant source of pain in BS. These insights contribute to our understanding of the pathophysiology of BS and support treatment paradigms prioritizing pain control with medications such as NSAIDs before considering surgical intervention. Future studies with larger sample sizes and in vivo models are needed to further validate these findings and explore the changes in joint histology under biomechanical forces in LSTVs.

Pedicle Subtraction Osteotomies for Surgical Correction of Fixed Sagittal Imbalance: A Meta-Analysis and Systematic Review.

BACKGROUND AND OBJECTIVES: Disruption of the spine's sagittal balance is associated with significant negative impacts on quality of life. Compared with other spinal osteotomies, pedicle subtraction osteotomy (PSO), which can potentially offer greater correction, is considered technically challenging and performed at lower rates. The aim of this study was to review the use of PSO to correct fixed sagittal imbalance and assess its efficacy and associated perioperative complications. METHODS: In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, the PubMed, EBSCO host, MEDLINE, and Google Scholar databases were queried for full-text English manuscripts published from 1961 to 2022, exploring PSO for the management of fixed sagittal imbalance. Studies were included if they reported preoperative and postoperative radiographic measurements. The mean Methodological Index for Nonrandomized Studies (MINORS) for included articles was 9.6 ± 1.1. The outcomes of interest included etiology, operative time, blood loss, complications, radiographic outcomes, and patient-reported outcomes. Statistical analysis was performed using a random-effects, inverse variance-weighted meta-analysis of observational data. Pre and postoperative radiographic and clinical outcomes were compared using a Student t-test. RESULTS: Fourteen studies with 595 patients were included. Meta-analysis showed that the mean operative time was 7.2 ± 2.0 hours, and the average blood loss was 2033 ± 629 mL. After PSO, there was a significant improvement in sagittal vertebral axis (12.41-3.92 cm, P = .0003), LL (13.35°-42.60°, P = .000002), PSO angle (5.11° to -26.91°, P = .0001), and Oswestry Disability Index (55.36-27.35, P = .02). Common complications include pseudarthrosis (8.1%), neurological deficits (7.8%), and proximal junctional failure (6.0%). CONCLUSION: PSO offers significant correction of sagittal vertebral axis, lumbar lordosis, PSO angle, and Oswestry Disability Index scores despite its reduced utilization in recent years. Blood loss and high complication rates must be considered when evaluating the efficacy of this procedure; however, surgeon experience and operative techniques can be used to reduce morbidity.

Patients May Return to Work Sooner After Laminoplasty: Occupational Outcomes of the Cervical Spondylotic Myelopathy Surgical Trial.

BACKGROUND AND OBJECTIVES: Return-to-work (RTW) is an important outcome for employed patients considering surgery for cervical spondylotic myelopathy (CSM). We conducted a post hoc analysis of patients as-treated in the Cervical Spondylotic Myelopathy Surgical Trial, a prospective, randomized trial comparing surgical approaches for CSM to evaluate factors associated with RTW. METHODS: In the trial, patients were randomized (2:3) to either anterior surgery (anterior cervical decompression/fusion [ACDF]) or posterior surgery (laminoplasty [LP], or posterior cervical decompression/fusion [PCDF], at surgeon's discretion). Work status was recorded at 1, 3, 6, and 12 months postoperatively. For patients working full-time or part-time on enrollment, time to RTW was compared across as-treated surgical groups using discrete-time survival analysis. Multivariate logistic regression was used to assess predictors of RTW. Clinical outcomes were compared using a linear mixed-effects model. RESULTS: A total of 68 (42%) of 163 patients were working preoperatively and were analyzed. In total, 27 patients underwent ACDF, 29 underwent PCDF, and 12 underwent LP. 45 (66%) of 68 patients returned to work by 12 months. Median time to RTW differed by surgical approach (LP = 1 month, ACDF = 3 months, PCDF = 6 months; P = .02). Patients with longer length-of-stay were less likely to be working at 1 month (odds ratio 0.51; 95% CI, 0.29-0.91; P = .022) and 3 months (odds ratio 0.39; 95% CI, 0.16-0.96; P = .04). At 3 months, PCDF was associated with lower Short-Form 36 physical component summary scores than ACDF (estimated mean difference [EMD]: 6.42; 95% CI, 1.4-11.4; P = .007) and LP (EMD: 7.98; 95% CI, 2.7-13.3; P = .003), and higher Neck Disability Index scores than ACDF (EMD: 12.48; 95% CI, 2.3-22.7; P = .01) and LP (EMD: 15.22; 95% CI, 2.3-28.1; P = .014), indicating worse perceived physical functioning and greater disability, respectively. CONCLUSION: Most employed patients returned to work within 1 year. LP patients resumed employment earliest, while PCDF patients returned to work latest, with greater disability at follow-up, suggesting that choice of surgical intervention may influence occupational outcomes.

Lumbar Facet Arthroplasty Versus Fusion for Grade-I Degenerative Spondylolisthesis with Stenosis: A Prospective Randomized Controlled Trial.

BACKGROUND: The comparative effectiveness of decompression plus lumbar facet arthroplasty versus decompression plus instrumented lumbar spinal fusion in patients with lumbar spinal stenosis and grade-I degenerative spondylolisthesis is unknown. METHODS: In this randomized, controlled, Food and Drug Administration Investigational Device Exemption trial, we assigned patients who had single-level lumbar spinal stenosis and grade-I degenerative spondylolisthesis to undergo decompression plus lumbar facet arthroplasty (arthroplasty group) or decompression plus fusion (fusion group). The primary outcome was a predetermined composite clinical success score. Secondary outcomes included the Oswestry Disability Index (ODI), visual analog scale (VAS) back and leg pain, Zurich Claudication Questionnaire (ZCQ), Short Form (SF)-12, radiographic parameters, surgical variables, and complications. RESULTS: A total of 321 adult patients were randomized in a 2:1 fashion, with 219 patients assigned to undergo facet arthroplasty and 102 patients assigned to undergo fusion. Of these, 113 patients (51.6%) in the arthroplasty group and 47 (46.1%) in the fusion group who had either reached 24 months of postoperative follow-up or were deemed early clinical failures were included in the primary outcome analysis. The arthroplasty group had a higher proportion of patients who achieved composite clinical success than did the fusion group (73.5% versus 25.5%; p < 0.001), equating to a between-group difference of 47.9% (95% confidence interval, 33.0% to 62.8%). The arthroplasty group outperformed the fusion group in most patient-reported outcome measures (including the ODI, VAS back pain, and all ZCQ component scores) at 24 months postoperatively. There were no significant differences between groups in surgical variables or complications, except that the fusion group had a higher rate of developing symptomatic adjacent segment degeneration. CONCLUSIONS: Among patients with lumbar spinal stenosis and grade-I degenerative spondylolisthesis, lumbar facet arthroplasty was associated with a higher rate of composite clinical success than fusion was at 24 months postoperatively. LEVEL OF EVIDENCE: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

C1-2 hypermobility and its impact on the spinal cord: a finite element analysis.

OBJECTIVE: The authors present a finite element analysis (FEA) evaluating the mechanical impact of C1-2 hypermobility on the spinal cord. METHODS: The Code_Aster program was used to perform an FEA to determine the mechanical impact of C1-2 hypermobility on the spinal cord. Normative values of Young's modulus were applied to the various components of the model, including bone, ligaments, and gray and white matter. Two models were created: 25° and 50° of C1-on-C2 rotation, and 2.5 and 5 mm of C1-on-C2 lateral translation. Maximum von Mises stress (VMS) throughout the cervicomedullary junction was calculated and analyzed. RESULTS: The FEA model of 2.5 mm lateral translation of C1 on C2 revealed maximum VMS for gray and white matter of 0.041 and 0.097 MPa, respectively. In the 5-mm translation model, the maximum VMS for gray and white matter was 0.069 and 0.162 MPa. The FEA model of 25° of C1-on-C2 rotation revealed maximum VMS for gray and white matter of 0.052 and 0.123 MPa. In the 50° rotation model, the maximum VMS for gray and white matter was 0.113 and 0.264 MPa. CONCLUSIONS: This FEA revealed significant spinal cord stress during pathological rotation (50°) and lateral translation (5 mm) consistent with values found during severe spinal cord compression and in patients with myelopathy. While this finite element model requires oversimplification of the atlantoaxial joint, the study provides biomechanical evidence that hypermobility within the C1-2 joint leads to pathological spinal cord stress.

Radiographic Alignment Parameters for Lumbosacral Reconstruction in Patients With Altered S1 Morphology.

STUDY DESIGN: Retrospective quantitative analysis study. OBJECTIVES: Pelvic incidence has been established as central radiographic marker which determines patient-specific correction goals during surgery for adult spinal deformity. In cases with sacral doming or sacral osteotomy where the PI cannot be calculated, reliable radiographic parameters need to be established to determine surgical goals. We aim to determine multiple radiographic parameters and formulas that can be utilized when the S1 superior endplate is obscured. METHODS: Retrospective analysis was performed on 68 healthy volunteers without prior spine surgery with full-length radiographs. Pelvic incidence, sacral slope, and pelvic tilt were calculated for each patient. Additional measurements such as L4, L5, and S2 incidence, tilt, and slope were collected. A new radiographic parameter defined as the L4-Sciatic notch angle was measured. Regression analysis was performed on each value to determine its relationship with S1 based incidence, tilt, and slope. RESULTS: Mean values for L5 incidence, L4 incidence, and L4 sciatic notch angle were 21.8° ± 8.9, 4.4° ± 8.1, and 44.4° ± 12, respectively. The linear regression analysis produced the following formulas which can be utilized to determine deformity correction goals when pelvic incidence can be calculated pre-operatively: L5i = .65*S1i-11.4, L4i = .44*S1i-18.6, and L4SNA = -.34*S1i + 66.5. In settings where pelvic incidence cannot be calculated, the following formulas can be utilized: L5i = .66*S2i-32.3 and L4SNA = -.02*S2i2 + 1.1*S2i + 63.5. P-values for all regression analyses were <.001. CONCLUSION: This study provides target radiographic alignment values that can be utilized for patients with either pre-operative altered S1 endplates or in cases with intraoperative alteration of S1 (sacral osteotomy).

Review of mechanisms of expandable spine surgery devices.

INTRODUCTION: Expandable devices such as interbody cages, vertebral body reconstruction cages, and intravertebral body expansion devices are frequently utilized in spine surgery. Since the introduction of expandable implants in the early 2000s, the variety of mechanisms that drive expansion and implant materials have steadily increased. By examining expandable devices that have achieved commercial success and exploring emerging innovations, we aim to offer an in-depth evaluation of the different types of expandable cages used in spine surgery and the underlying mechanisms that drive their functionality. AREAS COVERED: We performed a review of expandable spinal implants and devices by querying the National Library of Medicine MEDLINE database and Google Patents database from 1933 to 2024. Five major types of mechanical jacks that drive expansion were identified: scissor, pneumatic, screw, ratchet, and insertion-expansion. EXPERT OPINION: We identified a trend of screw jack mechanism being the predominant machinery in vertebral body reconstruction cages and scissor jack mechanism predominating in interbody cages. Pneumatic jacks were most commonly found in kyphoplasty devices. Critically reviewing the mechanisms of expansion and identifying trends among effective and successful cages allows both surgeons and medical device companies to properly identify future areas of development.

Exploring tribology and material contact science in spine surgery: implications for implant design.

Tribology, an interdisciplinary field concerned with the science of interactions between surfaces in contact and their relative motion, plays a well-established role in the design of orthopedic implants, such as knee and hip replacements. However, its applications in spine surgery have received comparatively less attention in the literature. Understanding tribology is pivotal in elucidating the intricate interactions between metal, polymer, and ceramic components, as well as their interplay with the native human bone. Numerous studies have demonstrated that optimizing tribological factors is key to enhancing the longevity of joints and implants while simultaneously reducing complications and the need for revision surgeries in both arthroplasty and spinal fusion procedures. With an ever-growing and diverse array of spinal implant devices hitting the market for static and dynamic stabilization of the spine, it is important to consider how each of these devices optimizes these parameters and what factors may be inadequately addressed by currently available technology and methods. In this comprehensive review, the authors' objectives were twofold: 1) delineate the unique challenges encountered in spine surgery that could be addressed through optimization of tribological parameters; and 2) summarize current innovations and products within spine surgery that look to optimize tribological parameters and highlight new avenues for implant design and research.

A retrospective analysis of perioperative complications of lateral approach lumbar interbody fusion in patients with prior abdominal surgery or a history of colonic inflammatory disease.

BACKGROUND CONTEXT: Lateral approaches for lumbar interbody fusion (LIF) allow for access to the lumbar spine and disk space by passing through a retroperitoneal corridor either pre- or trans-psoas. A contraindication for this approach is the presence of retroperitoneal scarring that may occur from prior surgical intervention in the retroperitoneal space or from inflammatory conditions with fibrotic changes and pose challenges for the mobilization and visualization needed in this approach. However, there is a paucity of evidence on the prevalence of surgical complications following lateral fusion surgery in patients with a history of abdominal surgery. PURPOSE: The primary aim of this study is to describe the association between surgical complications following lateral interbody fusion surgery and prior abdominal surgical. STUDY DESIGN: Retrospective study. PATIENT SAMPLE: Patients over the age of 18 who underwent lateral lumbar interbody fusion at a large, tertiary care center between 2011 and 2019 were included in the study. OUTCOME MEASURES: The primary outcome included medical, surgical, and thigh-related complications either in the intraoperative or 90-day postoperative periods. Additional outcome metrics included readmission rates, length of stay, and operative duration. METHODS: The electronic health records of 250 patients were reviewed for demographic information, surgical data, complications, and readmission following surgery. The association of patient and surgical factors to complication rate was analyzed using multivariable logistic regression. Statistical analysis was performed using R statistical software (R, Vienna, Austria). RESULTS: Of 250 lateral interbody fusion patients, 62.8% had a prior abdominal surgery and 13.8% had a history of colonic disease. The most common perioperative complication was transient thigh or groin pain/sensory changes (n=62, 24.8%). A multivariable logistic regression considering prior abdominal surgery, age, BMI, history of colonic disease, multilevel surgery, and the approach relative to psoas found no significant association between surgical complication rates and colonic disease (OR 0.40, 95% CI 0.02-2.22) or a history of prior abdominal surgeries (OR 0.56, 95% CI 0.20-1.55). Further, the invasiveness of prior abdominal surgeries showed no association with overall spine complication rate, lateral-specific complications, or readmission rates (p>.05). CONCLUSION: Though retroperitoneal scarring is an important consideration for lateral approaches to the lumbar spine, this study found no association between lateral lumbar approach complication rates and prior abdominal surgery. Further study is needed to determine the impact of inflammatory colonic disease on lateral approach spine surgery.

COVID-19 infection in patients with history of pediatric heart transplant in Germany, Austria, and Switzerland.

COVID-19 is a heterogenous infection-asymptomatic to fatal. While the course of pediatric COVID-19 infections is usually mild or even asymptomatic, individuals after adult heart transplantation are at high risk of a severe infection. We conducted a retrospective, multicenter survey of 16 pediatric heart transplant centers in Germany, Austria and Switzerland to evaluate the risk of a severe COVID-19 infection after pediatric heart transplantation between 02/2020 and 06/2021. Twenty-six subjects (11 male) with a median age of 9.77 years at time of transplantation and a median of 4.65 years after transplantation suffered from COVID-19 infection. The median age at time of COVID-10 infection was 17.20 years. Fourteen subjects had an asymptomatic COVID-19 infection. The most frequent symptoms were myalgia/fatigue (n = 6), cough (n = 5), rhinitis (n = 5), and loss of taste (n = 5). Only one subject showed dyspnea. Eleven individuals needed therapy in an outpatient setting, four subjects were hospitalized. One person needed oxygen supply, none of the subjects needed non-invasive or invasive mechanical ventilation. No specific signs for graft dysfunction were found by non-invasive testing. In pediatric heart transplant subjects, COVID-19 infection was mostly asymptomatic or mild. There were no SARS-CoV-2 associated myocardial dysfunction in heart transplant individuals.

Preoperative Mobile Health Data Improve Predictions of Recovery From Lumbar Spine Surgery.

BACKGROUND AND OBJECTIVES: Neurosurgeons and hospitals devote tremendous resources to improving recovery from lumbar spine surgery. Current efforts to predict surgical recovery rely on one-time patient report and health record information. However, longitudinal mobile health (mHealth) assessments integrating symptom dynamics from ecological momentary assessment (EMA) and wearable biometric data may capture important influences on recovery. Our objective was to evaluate whether a preoperative mHealth assessment integrating EMA with Fitbit monitoring improved predictions of spine surgery recovery. METHODS: Patients age 21-85 years undergoing lumbar surgery for degenerative disease between 2021 and 2023 were recruited. For up to 3 weeks preoperatively, participants completed EMAs up to 5 times daily asking about momentary pain, disability, depression, and catastrophizing. At the same time, they were passively monitored using Fitbit trackers. Study outcomes were good/excellent recovery on the Quality of Recovery-15 (QOR-15) and a clinically important change in Patient-Reported Outcomes Measurement Information System Pain Interference 1 month postoperatively. After feature engineering, several machine learning prediction models were tested. Prediction performance was measured using the c-statistic. RESULTS: A total of 133 participants were included, with a median (IQR) age of 62 (53, 68) years, and 56% were female. The median (IQR) number of preoperative EMAs completed was 78 (61, 95), and the median (IQR) number of days with usable Fitbit data was 17 (12, 21). 63 patients (48%) achieved a clinically meaningful improvement in Patient-Reported Outcomes Measurement Information System pain interference. Compared with traditional evaluations alone, mHealth evaluations led to a 34% improvement in predictions for pain interference (c = 0.82 vs c = 0.61). 49 patients (40%) had a good or excellent recovery based on the QOR-15. Including preoperative mHealth data led to a 30% improvement in predictions of QOR-15 (c = 0.70 vs c = 0.54). CONCLUSION: Multimodal mHealth evaluations improve predictions of lumbar surgery outcomes. These methods may be useful for informing patient selection and perioperative recovery strategies.

Implications of Preoperative Depression for Lumbar Spine Surgery Outcomes: A Systematic Review and Meta-Analysis.

Importance: Comorbid depression is common among patients with degenerative lumbar spine disease. Although a well-researched topic, the evidence of the role of depression in spine surgery outcomes remains inconclusive. Objective: To investigate the association between preoperative depression and patient-reported outcome measures (PROMs) after lumbar spine surgery. Data Sources: A systematic search of PubMed, Cochrane Database of Systematic Reviews, Embase, Scopus, PsychInfo, Web of Science, and ClinicalTrials.gov was performed from database inception to September 14, 2023. Study Selection: Included studies involved adults undergoing lumbar spine surgery and compared PROMs in patients with vs those without depression. Studies evaluating the correlation between preoperative depression and disease severity were also included. Data Extraction and Synthesis: All data were independently extracted by 2 authors and independently verified by a third author. Study quality was assessed using Newcastle-Ottawa Scale. Random-effects meta-analysis was used to synthesize data, and I2 was used to assess heterogeneity. Metaregression was performed to identify factors explaining the heterogeneity. Main Outcomes and Measures: The primary outcome was the standardized mean difference (SMD) of change from preoperative baseline to postoperative follow-up in PROMs of disability, pain, and physical function for patients with vs without depression. Secondary outcomes were preoperative and postoperative differences in absolute disease severity for these 2 patient populations. Results: Of the 8459 articles identified, 44 were included in the analysis. These studies involved 21 452 patients with a mean (SD) age of 57 (8) years and included 11 747 females (55%). Among these studies, the median (range) follow-up duration was 12 (6-120) months. The pooled estimates of disability, pain, and physical function showed that patients with depression experienced a greater magnitude of improvement compared with patients without depression, but this difference was not significant (SMD, 0.04 [95% CI, -0.02 to 0.10]; I2 = 75%; P = .21). Nonetheless, patients with depression presented with worse preoperative disease severity in disability, pain, and physical function (SMD, -0.52 [95% CI, -0.62 to -0.41]; I2 = 89%; P < .001), which remained worse postoperatively (SMD, -0.52 [95% CI, -0.75 to -0.28]; I2 = 98%; P < .001). There was no significant correlation between depression severity and the primary outcome. A multivariable metaregression analysis suggested that age, sex (male to female ratio), percentage of comorbidities, and follow-up attrition were significant sources of variance. Conclusions and Relevance: Results of this systematic review and meta-analysis suggested that, although patients with depression had worse disease severity both before and after surgery compared with patients without depression, they had significant potential for recovery in disability, pain, and physical function. Further investigations are needed to examine the association between spine-related disability and depression as well as the role of perioperative mental health treatments.

Ergonomics, musculoskeletal disorders, and surgeon gender in spine surgery: a survey of practicing spine surgeons.

OBJECTIVE: The objective of this study was to gain a greater understanding of the burden of musculoskeletal disorders (MSDs) in spine surgeons, their impact on practice, and risk factors contributing to MSDs, including surgical instrument design and surgical ergonomics. METHODS: An anonymous REDCap survey was distributed via email to the departments of several academic and private centers across the United States, as well as to the AANS/CNS Women in Neurosurgery Section email list. Chi-square tests and Wilcoxon rank-sum tests were used to compare responses by gender. Multivariable linear regression analysis was performed to identify predictors of discomfort in instrument utilization. RESULTS: Survey responses were received from 120 spine surgeons (29.1% response rate), of which 73 were included in the analysis. A very high number of respondents had experienced an MSD (70.4%), 38.2% had undergone treatment for at least one MSD, and 13.4% had lost time at work for at least one MSD. Women were more likely than men to have lost time at work due to an MSD (22.6% vs 5.6%, p = 0.04). Women were more likely than men to report difficulty in instrument grip, comfort, and use on a 20-point Likert scale (mean 10.7 vs 15.2 points, p < 0.0001). This effect persisted when adjusting for glove size and days per week spent operating (p = 0.002). Specifically, women were less likely to agree that the handles of surgical instruments were an appropriate grip (p < 0.0001), that they rarely experienced difficulty when using them (p < 0.0001), and that they rarely needed to use two hands with instruments meant to be used with one hand (p = 0.0002). CONCLUSIONS: The MSD burden in spine surgeons is substantial. While there was no evidence of gender differences in MSD rates and severity, female surgeons report significantly more discomfort with the use of surgical instruments. There is a need for more investigation of MSD risk factors in spine surgeons and mitigation strategies. Gender differences in comfort in instrument use should be further explored and addressed by spine surgeons and device manufacturers.

Factors affecting retirement and workforce attrition in neurosurgery: results of a Council of State Neurosurgical Societies national survey.

OBJECTIVE: By 2030, the US will not have enough neurosurgeons to meet the clinical needs of its citizens. Replacement of neurosurgeons due to attrition can take more than a decade, given the time-intensive training process. To identify potential workforce retention targets, the authors sought to identify factors that might impact neurosurgeons' retirement considerations. METHODS: The Council of State Neurosurgical Societies surveyed practicing AANS-registered neurosurgeons via email link to an online form with 25 factors that were ranked using a Likert scale of importance regarding retirement from the field (ranging from 1 for not important to 3 for very important). All participants were asked: "If you could afford it, would you retire today?" RESULTS: A total of 447 of 3200 neurosurgeons (14%) responded; 6% had been in practice for less than 5 years, 19% for 6-15 years, 57% for 16-30 years, and 18% for more than 30 years. Practice types included academic (18%), hospital employed (31%), independent with academic appointment (9%), and full independent practice (39%). The most common practice size was between 2 and 5 physicians (46%), with groups of 10 or more being the next most common (20%). Career satisfaction, income, and the needs of patients were rated as the most important factors keeping neurosurgeons in the workforce. Increasing regulatory burden, decreasing clinical autonomy, and the burden of insurance companies were the highest rated for factors important in considering retirement. Subgroup analysis by career stage, practice size, practice type, and geographic region revealed no significant difference in responses. When considering if they would retire now, 45% of respondents answered "yes." Subgroup analysis revealed that midcareer neurosurgeons (16-25 years in practice) were more likely to respond "yes" than those just entering their careers or in practice for more than 25 years (p = 0.03). This effect was confirmed in multivariate logistic regression (p = 0.04). These surgeons found professional satisfaction (p = 0.001), recertification requirements (p < 0.001), and maintaining high levels of income (p = 0.008) important to maintaining employment within the neurosurgical workforce. CONCLUSIONS: This study demonstrates that midcareer neurosurgeons may benefit from targeted retention efforts. This effort should focus on maximizing professional satisfaction and financial independence, while decreasing the regulatory burden associated with certification and insurance authorization. End-of-career surgeons should be surveyed to determine factors contributing to resilience and persistence within the neurosurgical workforce.

Reliability of a Novel Classification System for Thoracic Disc Herniations.

STUDY DESIGN: This is a cross-sectional survey. OBJECTIVE: The aim was to assess the reliability of a proposed novel classification system for thoracic disc herniations (TDHs). SUMMARY OF BACKGROUND DATA: TDHs are complex entities varying substantially in many factors, including size, location, and calcification. To date, no comprehensive system exists to categorize these lesions. METHODS: Our proposed system classifies 5 types of TDHs using anatomic and clinical characteristics, with subtypes for calcification. Type 0 herniations are small (≤40% of spinal canal) TDHs without significant spinal cord or nerve root effacement; type 1 are small and paracentral; type 2 are small and central; type 3 are giant (>40% of spinal canal) and paracentral; and type 4 are giant and central. Patients with types 1 to 4 TDHs have correlative clinical and radiographic evidence of spinal cord compression. Twenty-one US spine surgeons with substantial TDH experience rated 10 illustrative cases to determine the system's reliability. Interobserver and intraobserver reliability were determined using the Fleiss kappa coefficient. Surgeons were also surveyed to obtain consensus on surgical approaches for the various TDH types. RESULTS: High agreement was found for the classification system, with 80% (range 62% to 95%) overall agreement and high interrater and intrarater reliability (kappa 0.604 [moderate to substantial agreement] and kappa 0.630 [substantial agreement], respectively). All surgeons reported nonoperative management of type 0 TDHs. For type 1 TDHs, most respondents (71%) preferred posterior approaches. For type 2 TDHs, responses were roughly equivalent for anterolateral and posterior options. For types 3 and 4 TDHs, most respondents (72% and 68%, respectively) preferred anterolateral approaches. CONCLUSIONS: This novel classification system can be used to reliably categorize TDHs, standardize description, and potentially guide the selection of surgical approach. Validation of this system with regard to treatment and clinical outcomes represents a line of future study.

Catalytic antioxidant nanoparticles mitigate secondary injury progression and promote functional recovery in spinal cord injury model.

Traumatic spinal cord injury exacerbates disability with time due to secondary injury cascade triggered largely by overproduction of reactive oxygen species (ROS) at the lesion site, causing oxidative stress. This study explored nanoparticles containing antioxidant enzymes (antioxidant NPs) to neutralize excess ROS at the lesion site and its impact. When tested in a rat contusion model of spinal cord injury, a single dose of antioxidant NPs, administered intravenously three hours after injury, effectively restored the redox balance at the lesion site, interrupting the secondary injury progression. This led to reduced spinal cord tissue inflammation, apoptosis, cavitation, and inhibition of syringomyelia. Moreover, the treatment reduced scar tissue forming collagen at the lesion site, protected axons from demyelination, and stimulated lesion healing, with further analysis indicating the formation of immature neurons. The ultimate effect of the treatment was improved motor and sensory functions and rapid post-injury weight loss recovery. Histological analysis revealed activated microglia in the spinal cord displaying rod-shaped anti-inflammatory and regenerative phenotype in treated animals, contrasting with amoeboid inflammatory and degenerative phenotype in untreated control. Overall data suggest that restoring redox balance at the lesion site shifts the dynamics in the injured spinal cord microenvironment from degenerative to regenerative, potentially by promoting endogenous repair mechanisms. Antioxidant NPs show promise to be developed as an early therapeutic intervention in stabilizing injured spinal cord for enhanced recovery.

A Pilot Remote Curriculum to Enhance Resident and Medical Student Understanding of Machine Learning in Healthcare.

BACKGROUND: Despite the expanding role of machine learning (ML) in health care and patient expectations for clinicians to understand ML-based tools, few for-credit curricula exist specifically for neurosurgical trainees to learn basic principles and implications of ML for medical research and clinical practice. We implemented a novel, remotely delivered curriculum designed to develop literacy in ML for neurosurgical trainees. METHODS: A 4-week pilot medical elective was designed specifically for trainees to build literacy in basic ML concepts. Qualitative feedback from interested and enrolled students was collected to assess students' and trainees' reactions, learning, and future application of course content. RESULTS: Despite 15 interested learners, only 3 medical students and 1 neurosurgical resident completed the course. Enrollment included students and trainees from 3 different institutions. All learners who completed the course found the lectures relevant to their future practice as clinicians and researchers and reported improved confidence in applying and understanding published literature applying ML techniques in health care. Barriers to ample enrollment and retention (e.g., balancing clinical responsibilities) were identified. CONCLUSIONS: This pilot elective demonstrated the interest, value, and feasibility of a remote elective to establish ML literacy; however, feedback to increase accessibility and flexibility of the course encouraged our team to implement changes. Future elective iterations will have a semiannual, 2-week format, splitting lectures more clearly between theory (the method and its value) and application (coding instructions) and will make lectures open-source prerequisites to allow tailoring of student learning to their planned application of these methods in their practice and research.