Pain and aging: A unique challenge in neuroinflammation and behavior.

Chronic pain is one of the most common, costly, and potentially debilitating health issues facing older adults, with attributable costs exceeding $600 billion annually. The prevalence of pain in humans increases with advancing age. Yet, the contributions of sex differences, age-related chronic inflammation, and changes in neuroplasticity to the overall experience of pain are less clear, given that opposing processes in aging interact. This review article examines and summarizes pre-clinical research and clinical data on chronic pain among older adults to identify knowledge gaps and provide the base for future research and clinical practice. We provide evidence to suggest that neurodegenerative conditions engender a loss of neural plasticity involved in pain response, whereas low-grade inflammation in aging increases CNS sensitization but decreases PNS sensitivity. Insights from preclinical studies are needed to answer mechanistic questions. However, the selection of appropriate aging models presents a challenge that has resulted in conflicting data regarding pain processing and behavioral outcomes that are difficult to translate to humans.

Outcomes of patients undergoing single-level arthroplasty versus anterior lumbar interbody fusion.

BACKGROUND: Compared to vertebral body fusion, artificial discs are thought to lessen the risks of adjacent segment disease and the need for additional surgery by maintaining spinal mobility as they mimic the intervertebral disc structure. No studies have compared the rates of postoperative complications and the requirement for secondary surgery at adjacent segments among patients who have undergone anterior lumbar interbody fusions (ALIF) versus those undergoing lumbar arthroplasty. METHODS: An all-payer claims database identified 11,367 individuals who underwent single-level ALIF and lumbar arthroplasty for degenerative disc disease (DDD) between January 2010 and October 2020. Rates of complications following surgery, the need for additional lumbar surgeries, length of stay (LOS), and postoperative opioid utilization were assessed in matched cohorts based on logistic regression models. Kaplan-Meyer plots were created to model the probability of additional surgery. RESULTS: Following 1:1 exact matching, 846 records of patients who had undergone ALIF or lumbar arthroplasty were analyzed. All-cause readmission within 30-30 days following surgery was significantly higher in patients undergoing ALIF versus arthroplasty (2.6% vs. 0.71%, p = 0.02). LOS was significantly lower among the patients who had undergone ALIF (1.043 ± 0.21 vs. 2.17 ± 1.7, p < .001). CONCLUSIONS: ALIF and lumbar arthroplasty procedures are equally safe and effective in treating DDD. Our findings do not support that single-level fusions may biomechanically necessitate revisional surgeries.

The role of bone mineral density in adult spinal deformity patients undergoing corrective surgery: a matched analysis.

STUDY DESIGN: Retrospective cohort. BACKGROUND: Over 44 million adults are estimated to have either osteoporosis or osteopenia. Adult spinal deformity (ASD) is estimated to affect between 32 and 68% of the elderly population. OBJECTIVE: Retrospective investigation comparing rates of postoperative complications following thoracolumbar scoliosis surgery in patients with normal bone mineral density (BMD) to those with osteopenia or osteoporosis in addition to analyzing the effects of pretreatment with anti-osteoporotic medications in patients with low BMD. METHODS: Using administrative database of Humana beneficiaries, ICD-9 and ICD-10 diagnosis codes were used to identify ASD patients undergoing multilevel thoracolumbar fusions between 2007 and 2017. RESULTS: The propensity matched population analyzed in this study contained 1044 patients equally represented by those with a history of osteopenia, osteoporosis, or normal BMD. Osteopenia and osteoporosis were associated with increased odds of revision surgery (OR 2.01 95% CI 1.36-2.96 and OR 1.57, 95% CI 1.05-2.35), respectively. Similarly, there was an almost twofold increased odds of proximal and distal junctional kyphosis in patients with osteopenia and osteoporosis (OR 1.95, 95% CI 1.40-2.74 and OR 1.88, 95% CI 1.34-2.64), respectively. A total of 258 (37.1%) patients with osteoporosis were pretreated with anti-osteoporotic medications and there was no statistically significant decrease in odds of proximal or distal junctional kyphosis or revision surgery in these patients. CONCLUSION: Patients with ASD undergoing multilevel thoracolumbar fusion surgery have significantly higher rates of postoperative pseudarthrosis, proximal and distal junctional kyphosis, and revision surgery rates compared to patients with normal BMD.

Surgical Site Infection After Autologous Cranioplasty for Decompressive Craniectomy in Traumatic Brain Injury: A Retrospective Review of Two Level 1 Trauma Centers.

OBJECT: Surgical site infection (SSI) after cranioplasty can result in unnecessary morbidity. This analysis was designed to determine the risk factors of SSI after cranioplasty in patients who received a decompressive craniectomy with the autologous bone for traumatic brain injury (TBI). METHODS: A retrospective review was performed at two level 1 academic trauma centers for adult patients who underwent autologous cranioplasty after prior decompressive craniectomy for TBI. Demographic and procedural variables were collected and analyzed for associations with an increased incidence of surgical site infection with two-sample independent t tests and Mann Whitney U tests, and with a Bonferroni correction applied in cases of multiple comparisons. Statistical significance was reported with a P value of < 0.05. RESULTS: A total of 71 patients were identified. The mean interval from craniectomy to cranioplasty was 99 days (7-283), and 3 patients developed SSIs after cranioplasty (4.2%). Postoperative drain placement (P > 0.08) and administration of intrawound vancomycin powder (P = 0.99) were not predictive of infection risk. However, a trend was observed suggesting that administration of prophylactic preoperative IV vancomycin is associated with a reduced infection rate. CONCLUSIONS: The SSI rate after autologous cranioplasty in TBI patients is lower than previously reported for heterogeneous groups and indications, and the infection risk is comparable to other elective neurosurgical procedures. As such, the authors recommend attempting to preserve native skull and perform autologous cranioplasty in this population whenever possible.

Association of osteopenia and osteoporosis with higher rates of pseudarthrosis and revision surgery in adult patients undergoing single-level lumbar fusion.

OBJECTIVE: Patients with osteopenia or osteoporosis who require surgery for symptomatic degenerative spondylolisthesis may have higher rates of postoperative pseudarthrosis and need for revision surgery than patients with normal bone mineral densities (BMDs). To this end, the authors compared rates of postoperative pseudarthrosis and need for revision surgery following single-level lumbar fusion in patients with normal BMD with those in patients with osteopenia or osteoporosis. The secondary outcome was to investigate the effects of pretreatment with medications that prevent bone loss (e.g., teriparatide, bisphosphonates, and denosumab) on these adverse outcomes in this patient cohort. METHODS: Patients undergoing single-level lumbar fusion between 2007 and 2017 were identified. Based on 1:1 propensity matching for baseline demographic characteristics and comorbidities, 3 patient groups were created: osteopenia (n = 1723, 33.3%), osteoporosis (n = 1723, 33.3%), and normal BMD (n = 1723, 33.3%). The rates of postoperative pseudarthrosis and revision surgery were compared between groups. RESULTS: The matched populations analyzed in this study included a total of 5169 patients in 3 groups balanced at baseline, with equal numbers (n = 1723, 33.3%) in each group: patients with a history of osteopenia, those with a history of osteoporosis, and a control group of patients with no history of osteopenia or osteoporosis and with normal BMD. A total of 597 complications were recorded within a 2-year follow-up period, with pseudarthrosis (n = 321, 6.2%) being slightly more common than revision surgery (n = 276, 5.3%). The odds of pseudarthrosis and revision surgery in patients with osteopenia were almost 2-fold (OR 1.7, 95% CI 1.26-2.30) and 3-fold (OR 2.73, 95% CI 1.89-3.94) higher, respectively, than those in patients in the control group. Similarly, the odds of pseudarthrosis and revision surgery in patients with osteoporosis were almost 2-fold (OR 1.92, 95% CI 1.43-2.59) and > 3-fold (OR 3.25, 95% CI 2.27-4.65) higher, respectively, than those in patients in the control group. Pretreatment with medications to prevent bone loss prior to surgery was associated with lower pseudarthrosis and revision surgery rates, although the differences did not reach statistical significance. CONCLUSIONS: Postoperative pseudarthrosis and revision surgery rates following single-level lumbar spinal fusion are significantly higher in patients with osteopenia and osteoporosis than in patients with normal BMD. Pretreatment with medications to prevent bone loss prior to surgery decreased these complication rates, although the observed differences did not reach statistical significance.

Pediatric Brainstem Gliomas: A Retrospective Study of 180 Patients from the SEER Database.

BACKGROUND/AIMS: Large population-based studies are needed to assess the epidemiology and survival risk factors associated with pediatric brainstem gliomas. This retrospective study explores factors that may influence survival in this population. METHODS: Utilizing the SEER database, the authors retrospectively assessed survival in histologically confirmed brainstem gliomas in patients aged 17 and younger. Survival was described with Kaplan-Meyer curves and multivariate regression analysis. RESULTS: This analysis of 180 cases showed that age (hazard ratio [HR] 1.04, 95% CI 0.96-1.14, p = 0.34), non-white race (HR 1.00, 95% CI 0.35-2.85 p > 0.99), distant or invasive extension of the tumor (HR 0.4, 95% CI 0.08-2.53, p = 0.37), and radiation therapy (HR 1.27, 95% CI 0.52-3.11, p = 0.61) were not associated with decreased survival. High-grade tumor status (HR 8.64, 95% CI 3.49-21.41, p < 0.001) was associated with decreased survival. Partial resection (HR 0.11, 95% CI 0.04-0.30, p < 0.001) and gross-total resection (HR 0.03, 95% CI 0.01-0.14, p < 0.001) were associated with improved survival. CONCLUSIONS: High-grade brainstem gliomas have a worse prognosis. Early diagnosis and surgery appear to be associated with improved survival, while the role of radiation is unclear.

Cervical arthroplasty: what does the labeling say?

OBJECTIVE The aim of this paper was to comprehensively review each of the Food and Drug Administration (FDA)-approved labels of 7 total cervical disc replacements, assess the exact methodology in which the trial was conducted, and provide a broad comparison of these devices to allow each surgeon to determine which disc best suits his or her specific treatment goals based on the specific labels and not the studies published. METHODS The FDA-approved labels for each of the 7 artificial discs were obtained from the official FDA website. These labels were meticulously compared with regard to the statistical analysis performed, the safety and efficacy data, and the randomized controlled trial that each artificial disc was involved in to obtain the FDA approval for the product or device. Both single-level and 2-level approvals were examined, and primary and secondary end points were assessed. RESULTS In the single-level group, 4 of the 7 artificial discs-Prestige LP, Prestige ST, Bryan, and Secure-C-showed superiority in overall success. Prestige ST showed superiority in 3 of 4 outcome measures (neurological success, revision surgery, and overall success), while the other aforementioned discs showed superiority in 2 or fewer measures (Prestige LP, neurological and overall success; Bryan, Neck Disability Index [NDI] and overall success; Secure-C, revision surgery and overall success; Pro-Disc C, revision surgery). The PCM and Mobi-C discs demonstrated noninferiority across all outcome measures. In the 2-level group, Prestige LP and Mobi-C demonstrated superiority in 3 outcome measures (NDI, secondary surgery, and overall success) but not neurological success. CONCLUSIONS This paper provides a comprehensive analysis of 7 currently approved and distributed artificial discs in the United States. It compares specific outcome measures of these devices against those following the standard of care, which is anterior cervical discectomy and fusion. This information will provide surgeons the opportunity to easily answer patients' questions and remain knowledgeable when discussing devices with manufacturers.

Cost per quality-adjusted life year gained of revision fusion for lumbar pseudoarthrosis: defining the value of surgery.

STUDY DESIGN: Single cohort study of patients undergoing revision fusion for lumbar pseudoarthrosis. OBJECTIVE: To assess the 2-year comprehensive costs of revision arthrodesis for lumbar pseudoarthrosis at our institution and determine the associated cost per quality-adjusted life year (QALY) gained in this patient population. SUMMARY OF BACKGROUND DATA: The proportion of lumbar spine operations involving a fusion procedure has increased over the past 2 decades. Similarly, there has been a corresponding increase in the incidence and prevalence of pseudoarthrosis. However, the cost-effectiveness of revision surgery for pseudoarthrosis-associated back pain has yet to be examined. METHODS: Forty-seven patients undergoing revision instrumented arthrodesis for pseudoarthrosis-associated back pain were included. Two-year total back-related medical resource utilization, missed work, and health-state values (QALYs, calculated from EuroQuol 5D with US valuation) were assessed. Two-year resource use was multiplied by unit costs based on Medicare national allowable payment amounts (direct cost) and patient and care-giver work-day losses were multiplied by the self-reported gross-of-tax wage rate (indirect cost). The mean total 2-year cost per QALY gained after revision surgery was assessed. RESULTS: The mean (±SD) duration of time between prior fusion and development of symptomatic pseudoarthrosis was 2.69±3.09 years. None of the patients developed symptomatic pseudoarthrosis after 2 years of revision surgery. A mean cumulative 2-year gain of 0.35 QALYs was reported. The mean (±SD) total 2-year cost of revision fusion was $41,631±$9691 (surgery cost: $23,865±$270; outpatient resource utilization cost: $4885±$2301; indirect cost: $12,879±$8171). Revision instrumented arthrodesis was associated with a mean 2-year cost per QALY gained of $118,945. CONCLUSIONS: Revision arthrodesis was associated with improved 2-year quality of life in patients with pseudoarthrosis-related back pain. Nevertheless, in our experience revision surgery was shown to be marginally cost-effective at $118,945 per QALY gained.

Long-term outcomes after revision neural decompression and fusion for same-level recurrent lumbar stenosis: defining the effectiveness of surgery.

STUDY DESIGN: Single-cohort study of patients undergoing revision neural decompression and fusion for same-level recurrent lumbar stenosis. OBJECTIVE: To assess the long-term outcomes of revision surgery using validated patient-reported outcomes measures. SUMMARY OF BACKGROUND DATA: Recurrent lumbar stenosis may occur after lumbar spine surgery, leading to significant discomfort and radicular pain. Although numerous studies have reported clinical outcomes after primary lumbar surgery, there remains a paucity of data on the outcomes after revision surgery for recurrent same-level stenosis. METHODS: Fifty-three patients undergoing revision neural decompression and instrumented fusion for same-level recurrent stenosis-associated back and leg pain were included in this study. Baseline and 2-year visual analog scale for leg pain (LP-VAS), visual analog scale for low back pain (BP-VAS), Oswestry Disability Index (ODI), Zung self-reported depression score (ZDS), time to narcotic independence, time to return to work, health-state utility [EuroQol (EQ-5D)], and physical and mental quality of life [SF-12 physical and mental component scores (PCS and MCS)] were assessed. RESULTS: Mean±SD duration of time between index surgery and revision surgery was 4.00±4.19 years. A significant improvement from baseline was observed in BP-VAS (9.28±1.01 vs. 5.00±2.94, P=0.001), LP-VAS (9.55±0.93 vs. 3.45±2.95, P=0.001), and ODI (36.02±6.01 vs. 21.75±12.08, P=0.001). Mean±SD SF-12 PCS (7.17±11.22, P=0.001), SF-12 MCS (12.57±13.03, P=0.001), ZDS (12.37±16.80, P=0.001), and EQ-5D (0.42±0.34, P=0.001) were also significantly improved. The mean cumulative 2-year gain in health-utility state was 0.84 QALY. Median (interquartile range) duration of postoperative narcotic use was 6 (1.4-12.2) months and time of missed work was 6 (4.0-10.0) months. CONCLUSIONS: Our study suggests that revision neural decompression and instrumented fusion for recurrent same-level stenosis provides significant improvement in all patient-assessed outcome metrics and should be offered as a viable treatment option.

Sociodemographics Impact Competitiveness in the Neurosurgical Match: Survey Results.

BACKGROUND: The neurosurgical match involves selecting future neurosurgeons who will comprise the future national workforce, based on a competitive ranking process of applicants. We aimed to identify which sociodemographic and academic factors influence competitiveness and rank position in the match. METHODS: A Council of State Neurosurgical Societies (CSNS) survey was distributed to current U.S. neurosurgical residents. The primary outcome measure was self-reported rank position of matched program. Variables included sociodemographic and academic metrics. Fisher exact, logistic regression, and t tests were performed. RESULTS: Among the 72 respondents, median United States Medical Licensing Examination Step 1 score was 248, 34.7% were Alpha Omega Alpha inductees, 77.8% completed 1-3 sub-internship rotations, median number of publications was 5, and 13.9% had a Ph.D. Sociodemographic analysis demonstrated that 69.4% were male and 30.6% were female. Applicants with a home neurosurgery program or of female gender had statistically significantly higher odds of matching into a top 3 program on their rank list (odds ratio = 9 and odds ratio = 6, respectively). Female applicants exhibited similar mean, but less variance, compared with male respondents for United States Medical Licensing Examination Step 1 scores and number of publications. Respondents with a top 3 program match were more likely to agree that the home program supported their pursuance of neurosurgery. CONCLUSIONS: Two sociodemographic factors were independently associated with high match rank: presence of home neurosurgery program and female gender. Female respondents reported consistently strong academic metrics (similar mean, but less variance, compared with male respondents).

The Impact of Preoperative Spinal Injection Timing on Postoperative Complications of Lumbar Decompression Surgery.

BACKGROUND AND OBJECTIVES: Epidural steroid injections (ESIs) are commonly used for lower back pain management. The effect of these injections on lumbar decompression surgery outcomes is hitherto underexplored. The study objective was to determine the impact of ESIs on postoperative rates of medical and surgical complications and to define the appropriate interval before lumbar decompression surgery. METHODS: This retrospective all-payer database analysis identified 587 651 adult patients undergoing one- to three-level laminectomies from January 2010 to October 2021. A 2:1 propensity score match accounting for comorbidities, levels of surgery, and demographics was performed to create two cohorts: (1) 43 674 patients who had received an ESI in the 90 days before laminectomy and (2) 87 348 patients who had not received an ESI. The primary outcome was the rates of medical and surgical complications between groups at 30 days postoperatively. Patients were divided into five cohorts based on injection time before surgery: 1 to 30 days, 31 to 45 days, 46 to 60 days, 61 to 75 days, and 76 to 90 days. Logistic regression was performed between groups to identify temporal associations of complication rates. Confidence intervals of 95% are provided when appropriate. P values < .01 were considered significant. RESULTS: Rates of medical complications within 30 days of surgery were significantly higher in those with ESI compared with control (4.83% vs 3.9%, P < .001). Cerebrospinal fluid (CSF) leak rates were increased in the ESI group at 0.28% vs 0.1% (P < .001), but surgical site infection rates were not significantly different between groups (1.31% vs 1.42% P = .11). ESI performed within 30 days was associated with increased odds of CSF leak (OR: 5.32, 95% CI: 3.96-7.15). CONCLUSION: Preoperative ESI increases the risk of CSF leak and medical complications after lumbar decompression. Because these complications were significantly associated with ESIs given 1 to 30 days before surgery, avoiding ESIs at least 30 days before surgery may be advisable.

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.

Ehlers-Danlos Syndrome is Associated with Increased Rates of Adjacent Segment Disease Following TLIF: A Propensity Matched Study.

BACKGROUND: Ehlers-Danlos syndrome (EDS) is a collection of connective tissue disorders which are often associated with tissue laxity and disc degeneration. However, the implications of EDS on the risk of adjacent segment disease (ASD) after transforaminal lumbar interbody fusion (TLIF) are not well described. The objective of this study is to compare the rates of ASD among patients with EDS and those without EDS. METHODS: Patients who underwent 1-3 level TLIF for degenerative disc disease between 2010-2022 were identified using the PearlDiver Mariner all-claims insurance database. Patients with all types of EDS were included. Patients undergoing surgery for tumors, trauma, or infection were excluded. 1:1 propensity matching was performed using demographic factors, medical comorbidities, and surgical factors which were significantly associated with ASD in a linear regression model. The primary outcome measure was the development of ASD. The secondary outcomes were the development of pseudoarthrosis, medical complications, and surgical complications. RESULTS: Propensity matching resulted in 2 equal groups of 85 patients who did or did not have EDS and underwent 1-3 level TLIF. Patients without EDS were less likely to experience ASD (RR 0.18, 95% CI 0.09-0.35, P < 0.001). There was no significant difference between the 2 patient groups with regards to a diagnosis of pseudoarthrosis, and there was no significant difference for all-cause medical and surgical complications between the 2 patient groups. CONCLUSIONS: After propensity matching to control for confounding variables, the findings of this study suggest that EDS may be associated with an increased risk of ASD following TLIF. Future studies are needed to corroborate these findings.

Synthetic Interbody Devices and Traditional Bone Graft Are Associated With a Similar Rate of Surgical Complications After 1-2 Level Anterior Cervical Discectomy and Fusions.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: To compare the rates of all-cause surgical complications of synthetic interbody devices versus allograft or autograft in patients undergoing 1-2 levels anterior cervical discectomy and fusion (ACDF) procedures. SUMMARY OF BACKGROUND DATA: Cervical degenerative disorders affect up to 60% of older adults in the United States. Both traditional allograft or autograft and synthetic interbody devices (polyetheretherketone or titanium) are used for decompression and arthrodesis, with increasing utilization of the latter. However, the differences in their postsurgical complication profiles are not well-characterized. PATIENTS AND METHODS: Patients who underwent 1-2 level ACDFs for cervical radiculopathy or myelopathy between 2010 and 2022 were identified using the PearlDiver Mariner all-claims insurance database. Patients undergoing surgery for nondegenerative pathologies, such as tumors, trauma, or infection, were excluded. 1:1 exact matching was performed based on factors that were significant predictors of all-cause surgical complications in a linear regression model. The primary outcome measure was the development of all-cause surgical complications after 1-2 level ACDFs. The secondary outcome was all-cause medical complications. RESULTS: 1:1 exact matching resulted in two equal groups of 11,430 patients who received treatment with synthetic interbody devices or allograft/autograft. No statistically significant difference in all-cause surgical complications was found between the synthetic cohort and the allograft or autograft cohort after 1-2 level ACDFs (Relative Risk: 0.86, 95% confidence interval: 0.730-1.014, P = 0.079). No significant differences were observed regarding any specific surgical complications except for pseudoarthrosis (Relative Risk: 0.73, 95% confidence interval: 0.554-0.974, P = 0.037), which was higher in the allograft/autograft cohort. CONCLUSION: After 1:1 exact matching to control for confounding variables, the findings of this study suggest that all-cause surgical complications are similar in patients undergoing ACDFs with synthetic interbody devices or allograft/autographs. However, the rate of pseudarthrosis appears to be higher in patients with allograft/autographs. Future prospective studies are needed to corroborate these findings.

A Neurosurgical Readmissions Reduction Program in an Academic Hospital Leveraging Machine Learning, Workflow Analysis, and Simulation.

BACKGROUND: Predicting 30-day hospital readmissions is crucial for improving patient outcomes, optimizing resource allocation, and achieving financial savings. Existing studies reporting the development of machine learning (ML) models predictive of neurosurgical readmissions do not report factors related to clinical implementation. OBJECTIVES: Train individual predictive models with good performance (area under the receiver operating characteristic curve or AUROC > 0.8), identify potential interventions through semi-structured interviews, and demonstrate estimated clinical and financial impact of these models. METHODS: Electronic health records were utilized with five ML methodologies: gradient boosting, decision tree, random forest, ridge logistic regression, and linear support vector machine. Variables of interest were determined by domain experts and literature. The dataset was split divided 80% for training and validation and 20% for testing randomly. Clinical workflow analysis was conducted using semi-structured interviews to identify possible intervention points. Calibrated agent-based models (ABMs), based on a previous study with interventions, were applied to simulate reductions of the 30-day readmission rate and financial costs. RESULTS: The dataset covered 12,334 neurosurgical intensive care unit (NSICU) admissions (11,029 patients); 1,903 spine surgery admissions (1,641 patients), and 2,208 traumatic brain injury (TBI) admissions (2,185 patients), with readmission rate of 13.13, 13.93, and 23.73%, respectively. The random forest model for NSICU achieved best performance with an AUROC score of 0.89, capturing potential patients effectively. Six interventions were identified through 12 semi-structured interviews targeting preoperative, inpatient stay, discharge phases, and follow-up phases. Calibrated ABMs simulated median readmission reduction rates and resulted in 13.13 to 10.12% (NSICU), 13.90 to 10.98% (spine surgery), and 23.64 to 21.20% (TBI). Approximately $1,300,614.28 in saving resulted from potential interventions. CONCLUSION: This study reports the successful development and simulation of an ML-based approach for predicting and reducing 30-day hospital readmissions in neurosurgery. The intervention shows feasibility in improving patient outcomes and reducing financial losses.

Correlation Between Rod Fracture and Shear Stress: A Novel Parameter.

BACKGROUND: We sought to assess the accuracy of a novel parameter proportional to the rod shear stress (RSS) in identifying patients at risk of rod fracture (RF) after surgery for correction of adult spinal deformity. METHODS: We performed a retrospective medical record review of patients aged ≥18 years treated for adult spinal deformity between 2004 and 2014 with ≥24 months of follow-up. The primary outcome was RFs identified radiographically. Patient weight (w), number of instrumented levels (N), and minimum rod diameter (d) were recorded and used to calculate the RSS parameter (RSS=Nwd2). Receiver operating characteristic curves were produced and the area under the curve (AUC ± 95% confidence interval [CI]) was calculated to compare this parameter's discriminative accuracy to that of its constituent variables. The sensitivity, specificity, and likelihood ratios (LRs) were calculated. RESULTS: A total of 28 RF-positive and 154 RF-negative patients were included. The average age was 59.2 ± 9.6 years, and 93.4% were women. The RSS parameter produced the greatest AUC (0.73 ± 0.11). At an RSS cutoff of 30.1, it achieved a sensitivity of 71.4% and specificity of 71.4% (LR, 2.5; 95% CI, 1.8-3.5). The number of instrumented levels produced the next-greatest AUC (0.65 ± 0.12), with a sensitivity of 78.6% and specificity of 50.0% at a cutoff of 15 (LR, 1.6; 95% CI, 1.2-2.0). CONCLUSIONS: The RSS is calculated using easily obtainable information and shows potential as a tool for predicting patient-specific risk of RF after spinal fusion. The number of instrumented levels also correlates strongly with the occurrence of RFs and is not significantly less accurate than the RSS. A larger sample size and prospective validation would be useful in determining with greater confidence which parameter is superior for predicting RFs after spinal fusion.

Cannabis Use is Associated With Higher Rates of Pseudarthrosis Following TLIF: A Multi-Institutional Matched-Cohort Study.

STUDY DESIGN: This was a retrospective cohort study. OBJECTIVE: To compare the rates of pseudarthrosis in patients undergoing 1 to 3 level transforaminal lumbar interbody fusion (TLIF) procedures between cannabis users and noncannabis users. SUMMARY OF BACKGROUND DATA: Recreational use of cannabis is common, though it remains poorly studied and legally ambiguous in the United States. Patients with back pain may turn to adjunctive use of cannabis to manage their pain. However, the implications of cannabis use on the achievement of bony fusion are not well-characterized. METHODS: Patients who underwent 1 to 3 level TLIF for degenerative disc disease or degenerative spondylolisthesis between 2010 and 2022 were identified using the PearlDiver Mariner all-claims insurance database. Cannabis users were identified with ICD 10 code F12.90. Patients undergoing surgery for nondegenerative pathologies such as tumors, trauma, or infection were excluded. 1:1 exact matching was performed using demographic factors, medical comorbidities, and surgical factors which were significantly associated with pseudarthrosis in a linear regression model. The primary outcome measure was development of pseudarthrosis within 24 months after 1 to 3 level TLIF. The secondary outcomes were the development of all-cause surgical complications as well as all-cause medical complications. RESULTS: A 1:1 exact matching resulted in two equal groups of 1593 patients who did or did not use cannabis and underwent 1 to 3 level TLIF. Patients who used cannabis were 80% more likely to experience pseudarthrosis compared with patients who do not [relative risk (RR): 1.816, 95% CI: 1.291-2.556, P <0.001]. Similarly, cannabis use was associated with significantly higher rates of all-cause surgical complications (RR: 2.350, 95% CI: 1.399-3.947, P =0.001) and all-cause medical complications (RR: 1.934, 95% CI: 1.516-2.467, P <0.001). CONCLUSION: After 1:1 exact matching to control for confounding variables, the findings of this study suggest that cannabis use is associated with higher rates of pseudarthrosis, as well as higher rates of all-cause surgical and all-cause medical complications. Further studies are needed to corroborate our findings.

Cerebellopontine angle meningiomas: postoperative outcomes in a modern cohort.

OBJECT: Tumors of the cerebellopontine angle (CPA) have always proven difficult for neurosurgeons to optimally manage. Studies investigating the natural history and treatment of vestibular schwannomas have dominated the literature in this regard. Distinguishing meningiomas from schwannomas in this location carries particular importance as each tumor type has certain prognostic and surgical considerations. In this study, the authors have characterized the outcomes of 34 patients surgically treated for CPA meningiomas and have investigated various factors that may affect postoperative neurological function. METHODS: The medical records of patients with CPA meningiomas who underwent surgery from 2005 to 2013 at the Duke University Health System were reviewed. Various patient, clinical, and tumor data were gathered from the medical records including patient demographics, pre- and postoperative neurological examinations, duration of symptoms, procedural details, tumor pathology and size, and treatment characteristics. Differences in continuous variables were then analyzed using the Student t-test while categorical variables were evaluated using the chi-square test. RESULTS: A total of 34 patients underwent surgical treatment for CPA meningiomas during the 8-year period. Jugular foramen invasion was seen in 17.6% of tumors, with nearly half (41.2%) extending into the internal acoustic canal. The most common presenting symptom was hearing loss (58.8%), followed by headache (52.9%) and facial numbness/pain (50.0%). The most common cranial nerve (CN) affected was CN X (11.8%), followed by CNs VI and VII (5.9%). Postoperatively, no patients experienced a decrease in hearing, with only 5.9% of patients experiencing facial nerve palsies. Patients with tumors larger than 3 cm had a significantly higher incidence of permanent CN deficits than those with smaller tumors (45.5% vs 5.9%, respectively; p = 0.011). Also, tumor extension into the jugular foramen was associated with the occurrence of lower CN deficits, none of which occurred in tumors without jugular foramen invasion. Internal acoustic canal tumor extension was not seen to be associated with postoperative complications or CN deficits. CONCLUSIONS: Meningiomas of the CPA are challenging lesions to treat surgically. However, the risk of facial palsy and hearing loss is significantly lower when compared with vestibular schwannomas. Novel methods for preoperative differentiation are needed to appropriately counsel patients on surgical risks. Also, due to the significant potential for neurological deficits, further studies are needed to investigate the utility of radiotherapy for these lesions.

Cost-utility analysis of minimally invasive versus open multilevel hemilaminectomy for lumbar stenosis.

STUDY DESIGN: Two-year cost-utility study comparing minimally invasive (MIS) versus open multilevel hemilaminectomy in patients with degenerative lumbar spinal stenosis. OBJECTIVE: The objective of the study was to determine whether MIS versus open multilevel hemilaminectomy for degenerative lumbar spinal stenosis is a cost-effective advancement in lumbar decompression surgery. SUMMARY OF BACKGROUND DATA: MIS-multilevel hemilaminectomy for degenerative lumbar spinal stenosis allows for effective treatment of back and leg pain while theoretically minimizing blood loss, tissue injury, and postoperative recovery. No studies have evaluated comprehensive healthcare costs associated with multilevel hemilaminectomy procedures, nor assessed cost-effectiveness of MIS versus open multilevel hemilaminectomy. METHODS: Fifty-four consecutive patients with lumbar stenosis undergoing multilevel hemilaminectomy through an MIS paramedian tubular approach (n=27) versus midline open approach (n=27) were included. Total back-related medical resource utilization, missed work, and health state values [quality adjusted life years (QALYs), calculated from EuroQuol-5D with US valuation] were assessed after 2-year follow-up. Two-year resource use was multiplied by unit costs based on Medicare national allowable payment amounts (direct cost) and work-day losses were multiplied by the self-reported gross-of-tax wage rate (indirect cost). Difference in mean total cost per QALY gained for MIS versus open hemilaminectomy was assessed as incremental cost-effectiveness ratio (ICER: COST(MIS)-COST(OPEN)/QALY(MIS)-QALY(OPEN)). RESULTS: MIS versus open cohorts were similar at baseline. MIS and open hemilaminectomy were associated with an equivalent cumulative gain of 0.72 QALYs 2 years after surgery. Mean direct medical costs, indirect societal costs, and total 2-year cost ($23,109 vs. $25,420; P=0.21) were similar between MIS and open hemilaminectomy. MIS versus open approach was associated with similar total costs and utility, making it a cost equivalent technology compared with the traditional open approach. CONCLUSIONS: MIS versus open multilevel hemilaminectomy was associated with similar cost over 2 years while providing equivalent improvement in QALYs. In our experience, MIS versus open multilevel hemilaminectomy is a cost equivalent technology for patients with lumbar stenosis-associated radicular pain.

Clin-STAR corner: 2021 update in musculoskeletal pain in older adults with a focus on osteoarthritis-related pain.

Chronic musculoskeletal (MSK) pain remains a leading cause of disability and functional impairment among older adults and is associated with substantial societal and personal costs. Chronic pain is particularly challenging to manage in older adults because of multimorbidity, concerns about treatment-related harm, as well as older adults' beliefs about pain and its management. This narrative review presents data on nine high-quality, peer-reviewed clinical trials published primarily over the past two years that focus on MSK pain management in older adults, of which four were comprehensively reviewed. These studies address contributors to knee osteoarthritis (OA) pain (insomnia), provide evidence for digital delivery or artificial intelligence driven behavioral interventions and potentially more efficient/equally effective modes of delivering glucocorticoids for OA; each of the selected studies have potential for scalability and meaningful impact in the care of older adults.