Association of Malnutrition with Surgical and Hospital Outcomes after Spine Surgery for Spinal Metastases: A National Surgical Quality Improvement Program Study of 1613 Patients.

Background: Malnutrition is a common condition that may exacerbate many medical and surgical pathologies. However, few have studied the impact of malnutrition on surgical outcomes for patients undergoing surgery for metastatic disease of the spine. This study aims to evaluate the impact of malnutrition on perioperative complications and healthcare resource utilization following surgical treatment of spinal metastases. Methods: We conducted a retrospective cohort study using the 2011-2019 American College of Surgeons National Surgical Quality Improvement Program database. Adult patients with spinal metastases who underwent laminectomy, corpectomy, or posterior fusion for extradural spinal metastases were identified using the CPT, ICD-9-CM, and ICD-10-CM codes. The study population was divided into two cohorts: Nourished (preoperative serum albumin values ≥ 3.5 g/dL) and Malnourished (preoperative serum albumin values < 3.5 g/dL). We assessed patient demographics, comorbidities, intraoperative variables, postoperative adverse events (AEs), hospital LOS, discharge disposition, readmission, and reoperation. Multivariate logistic regression analyses were performed to identify the factors associated with a prolonged length of stay (LOS), AEs, non-routine discharge (NRD), and unplanned readmission. Results: Of the 1613 patients identified, 26.0% were Malnourished. Compared to Nourished patients, Malnourished patients were significantly more likely to be African American and have a lower BMI, but the age and sex were similar between the cohorts. The baseline comorbidity burden was significantly higher in the Malnourished cohort compared to the Nourished cohort. Compared to Nourished patients, Malnourished patients experienced significantly higher rates of one or more AEs (Nourished: 19.8% vs. Malnourished: 27.6%, p = 0.004) and serious AEs (Nourished: 15.2% vs. Malnourished: 22.6%, p < 0.001). Upon multivariate regression analysis, malnutrition was found to be an independent and associated with an extended LOS [aRR: 3.49, CI (1.97, 5.02), p < 0.001], NRD [saturated aOR: 1.76, CI (1.34, 2.32), p < 0.001], and unplanned readmission [saturated aOR: 1.42, CI (1.04, 1.95), p = 0.028]. Conclusions: Our study suggests that malnutrition increases the risk of postoperative complication, prolonged hospitalizations, non-routine discharges, and unplanned hospital readmissions. Further studies are necessary to identify the protocols that pre- and postoperatively optimize malnourished patients undergoing spinal surgery for metastatic spinal disease.

Racial disparities in the management and outcomes of primary osseous neoplasms of the spine: a SEER analysis.

PURPOSE: Primary osseous neoplasms of the spine, including Ewing's sarcoma, osteosarcoma, chondrosarcoma, and chordoma, are rare tumors with significant morbidity and mortality. The present study aims to identify the prevalence and impact of racial disparities on management and outcomes of patients with these malignancies. METHODS: The 2000 to 2020 Surveillance, Epidemiology, and End Results (SEER) Registry, a cancer registry, was retrospectively reviewed to identify patients with Ewing's sarcoma, osteosarcoma, chondrosarcoma, or chordoma of the vertebral column or sacrum/pelvis. Study patients were divided into race-based cohorts: White, Black, Hispanic, and Other. Demographics, tumor characteristics, treatment variables, and mortality were assessed. RESULTS: 2,415 patients were identified, of which 69.8% were White, 5.8% Black, 16.1% Hispanic, and 8.4% classified as "Other". Tumor type varied significantly between cohorts, with osteosarcoma affecting a greater proportion of Black patients compared to the others (p < 0.001). A lower proportion of Black and Other race patients received surgery compared to White and Hispanic patients (p < 0.001). Utilization of chemotherapy was highest in the Hispanic cohort (p < 0.001), though use of radiotherapy was similar across cohorts (p = 0.123). Five-year survival (p < 0.001) and median survival were greatest in White patients (p < 0.001). Compared to non-Hispanic Whites, Hispanic (p < 0.001) and "Other" patients (p < 0.001) were associated with reduced survival. CONCLUSION: Race may be associated with tumor characteristics at diagnosis (including subtype, size, and site), treatment utilization, and mortality, with non-White patients having lower survival compared to White patients. Further studies are necessary to identify underlying causes of these disparities and solutions for eliminating them.

Novel Intrafraction Motion Tracking During Postoperative Spine Stereotactic Irradiation for a Patient With Carbon Fiber Fixation Hardware.

Carbon-fiber reinforced (CFR) polyetheretherketone hardware is an alternative to traditional metal hardware used for spinal fixation surgeries before postoperative radiation therapy for patients with spinal metastases. CFR hardware's radiolucency decreases metal artifact, improving visualization and accuracy of treatment planning. We present the first clinical use and proof of principle of CFR spinal hardware with tantalum markers used for successful tracking of intrafraction motion (IM) using Varian TrueBeam IMR (Intrafraction Motion Review) software module during postoperative spine stereotactic radiation. A 63-year-old woman with history of endometrial cancer presented with acute back pain. Imaging demonstrated pathologic T12 vertebral fracture with cord compression. She underwent T12 vertebrectomy with circumferential decompression and posterior instrumented T10-L2 fusion at our facility using CFR-polyetheretherketone hardware with tantalum screw markers followed by postoperative stereotactic body radiation therapy to 3000 cGy in 5 fractions delivered to T11-T12. Tantalum screw markers were used for IMR tracking. During irradiation, 260 kV images were acquired, and IMR software was able to identify and track markers. During the entire treatment, the IM motions were less than 3 mm. This is the first presented case of CFR spinal hardware with tantalum markers used for successful IMR tracking of IM during daily spine stereotactic treatment. Future work will be needed to improve workflow and create a spine-specific IMR protocol.

Socioeconomic and Racial/Ethnic Disparities in Perception of Health Status and Literacy in Spine Oncological Patients: Insights from the All of Us Research Program.

STUDY DESIGN: A cross-sectional study was performed using the National Institutes of Health All of Us survey database. OBJECTIVE: The aim of this study was to assess socioeconomic and racial disparities in the perception of personal health, health literacy, and healthcare access among spine oncology patients. SUMMARY OF BACKGROUND DATA: Racial, ethnic, and socioeconomic disparities in health literacy and perception of health status have been described for many disease processes. However, few studies have assessed the prevalence of these disparities among spine oncology patients. METHODS: Adult spine oncology patients, identified using ICD-9/10-CM codes, were categorized by race/ethnicity: White/Caucasian (WC), Black/African-American (BAA), and Non-White Hispanic (NWH). Demographics and socioeconomic status were assessed. Questionnaire responses regarding baseline health status, perception of health status, health literacy, and barriers to healthcare were compared. RESULTS: Of the 1,175 patients identified, 207 (17.6%) were BAA, 267 (22.7%) were NWH, and 701 (59.7%) were WC. Socioeconomic status varied among cohorts, with WC patients reporting higher levels of education ( P<0.001 ), annual income greater than $50K ( P<0.001 ), and home ownership ( P<0.001 ). BAA and NWH patients reported greater rates of 7-day "Severe fatigue" ( P<0.001 ) and "10/10 pain" ( P<0.001 ) and lower rates of "Completely" able to perform everyday activities ( P<0.001 ). WC patients had a higher response rate for "Excellent/Very Good" regarding their own general health ( P<0.001 ) and quality ( P<0.001 ). The WC cohort had a significantly higher proportion of patients responding "Never" when assessing difficulty understanding ( P<0.001 ) and needing assistance with health materials ( P<0.001 ). BAA and NWH were significantly less likely to report feeling "Extremely" confident with medical forms ( P<0.001 ). BAA and NWH had significantly higher response rates to feeling "Somewhat Worried" about healthcare costs ( P<0.001 ) and with delaying medical care given "Can't Afford Co-pay" ( P<0.001 ). CONCLUSION: We identified disparities in perception of health status, literacy, and access among spine oncology patients. LEVEL OF EVIDENCE: 4.

Differences in Outcomes and Health Care Resource Utilization After Surgical Intervention for Metastatic Spinal Column Tumor in Safety-Net Hospitals.

STUDY DESIGN: Observational cohort study. OBJECTIVE: The aim of this study was to investigate the association between safety-net hospital (SNH) status and hospital length of stay (LOS), cost, and discharge disposition in patients undergoing surgery for metastatic spinal column tumors. SUMMARY OF BACKGROUND DATA: SNHs serve a high proportion of Medicaid and uninsured patients. However, few studies have assessed the effects of SNH status on outcomes after surgery for metastatic spinal column tumors. PATIENTS AND METHODS: This study was performed using the 2016-2019 Nationwide Inpatient Sample database. All adult patients undergoing metastatic spinal column tumor surgeries, identified using ICD-10-CM coding, were stratified by SNH status, defined as hospitals in the top quartile of Medicaid/uninsured coverage burden. Hospital characteristics, demographics, comorbidities, intraoperative variables, postoperative complications, and outcomes were assessed. Multivariable analyses identified independent predictors of prolonged LOS (>75th percentile of cohort), nonroutine discharge, and increased cost (>75th percentile of cohort). RESULTS: Of the 11,505 study patients, 24.0% (n = 2760) were treated at an SNH. Patients treated at SNHs were more likely to be Black-identifying, male, and lower income quartile. A significantly greater proportion of patients in the non-SNH (N-SNH) cohort experienced any postoperative complication [SNH: 965 (35.0%) vs . N-SNH: 3535 (40.4%), P = 0.021]. SNH patients had significantly longer LOS (SNH: 12.3 ± 11.3 d vs . N-SNH: 10.1 ± 9.5 d, P < 0.001), yet mean total costs (SNH: $58,804 ± 39,088 vs . N-SNH: $54,569 ± 36,781, P = 0.055) and nonroutine discharge rates [SNH: 1330 (48.2%) vs . N-SNH: 4230 (48.4%), P = 0.715) were similar. On multivariable analysis, SNH status was significantly associated with extended LOS [odds ratio (OR): 1.41, P = 0.009], but not nonroutine discharge disposition (OR: 0.97, P = 0.773) or increased cost (OR: 0.93, P = 0.655). CONCLUSIONS: Our study suggests that SNHs and N-SNHs provide largely similar care for patients undergoing metastatic spinal tumor surgeries. Patients treated at SNHs may have an increased risk of prolonged hospitalizations, but comorbidities and complications likely contribute greater to adverse outcomes than SNH status alone. LEVEL OF EVIDENCE: 3.

Prevalence and Influence of Frailty on Hospital Outcomes After Surgical Resection of Spinal Meningiomas.

OBJECTIVE: Frailty has been shown to affect patient outcomes after medical and surgical interventions. The Hospital Frailty Risk Score (HFRS) is a growing metric used to assess patient frailty using International Classification of Diseases, Tenth Revision codes. The goal of this study was to investigate the impact of frailty, assessed by HFRS, on health care resource utilization and outcomes in patients undergoing surgery for spinal meningiomas. METHODS: A retrospective cohort study was performed using the 2016-2019 National Inpatient Sample database. Adult patients with benign or malignant spinal meningiomas, identified using International Classification of Diseases, Tenth Revision, Clinical Modification codes, were stratified by HFRS: low frailty (HFRS <5) and intermediate-high frailty (HFRS ≥5). Patient demographics, hospital characteristics, comorbidities, procedural variables, adverse events, length of stay (LOS), discharge disposition, and cost of admission were assessed. Multivariate regression analysis was used to identify predictors of increased LOS, discharge disposition, and cost. RESULTS: Of the 3345 patients, 530 (15.8%) had intermediate-high frailty. The intermediate-high cohort was significantly older (P < 0.001). More patients in the intermediate-high cohort had ≥3 comorbidities (P < 0.001). In addition, a greater proportion of patients in the intermediate-high cohort experienced ≥1 perioperative adverse events (P < 0.001). Intermediate-high patients experienced greater mean LOS (P < 0.001) and accrued greater costs (P < 0.001). A greater proportion of intermediate-high patients had nonroutine discharges (P < 0.001). On multivariate analysis, increased HFRS (≥5) was independently associated with extended LOS (adjusted odds ratio [aOR], 3.04; P < 0.001), nonroutine discharge (aOR, 1.98; P = 0.006), and increased costs (aOR, 2.39; P = 0.004). CONCLUSIONS: Frailty may be associated with increased health care resource utilization in patients undergoing surgery for spinal meningiomas.

A current review of spinal meningiomas: epidemiology, clinical presentation and management.

PURPOSE: To provide an up-to-date review of the epidemiology, histopathology, molecular biology, and etiology of spinal meningiomas, as well as discuss the clinical presentation, clinical evaluation, and most recent treatment recommendations for these lesions. METHODS: PubMed and Google Scholar search was performed for studies related to meningiomas of the spine. The terms "meningioma," "spinal meningioma," "spine meningioma," "meningioma of the spine," "benign spinal tumors," and "benign spine tumors," were used to identify relevant studies. All studies, including primary data papers, meta-analyses, systematic reviews, general reviews, case reports, and clinical trials were considered for review. RESULTS: Eighty-four studies were identified in the review. There were 22 studies discussing adverse postoperative outcomes, 21 studies discussing tumor genetics, 19 studies discussing epidemiology and current literature, 9 studies discussing radiation modalities and impact on subsequent tumor development, 5 studies on characteristic imaging findings, 5 studies discussing hormone use/receptor status on tumor development, 2 discussing operative techniques and 1 discussing tumor identification. CONCLUSION: Investigations into spinal meningiomas generally lag behind that of intracranial meningiomas. Recent advancements in the molecular profiling of spinal meningiomas has expanded our understanding of these tumors, increasing our appreciation for their heterogeneity. Continued investigation into the defining characteristics of different spinal meningiomas will aid in treatment planning and prognostication.

Impact of Affective Disorders on Inpatient Opioid Consumption and Hospital Outcomes Following Open Posterior Spinal Fusion for Adult Spine Deformity.

OBJECTIVE: Affective disorders (ADs) are common and have a profound impact on surgical recovery, though few have studied the impact of ADs on inpatient narcotic consumption. The aim of this study was to assess the impact of ADs on inpatient narcotic consumption and healthcare resource utilization in patients undergoing spinal fusion for adult spinal deformity. METHODS: A retrospective cohort study was performed using the 2016-2017 Premier Healthcare Database. Adults who underwent adult spinal deformity surgery were identified using International Classification of Disease, Tenth Revision, codes. Patients were grouped based on comorbid diagnosis of an AD. Demographics, comorbidities, intraoperative variables, complications, length of stay, admission costs, and nonroutine discharge rates were assessed. Increased inpatient opioid use was categorized by morphine milligram equivalents consumption greater than the 75th percentile. Multivariate regression analysis was used to identify predictors of increased healthcare recourse utilization. RESULTS: Of the 1831 study patients, 674 (36.8%) had an AD. A smaller proportion of patients in the AD cohort were 65+ years of age (P = 0.001), while a greater proportion of patients in the AD cohort identified as non-Hispanic White (P < 0.001). A greater proportion of patients in the AD cohort had increased morphine milligram equivalents consumption (P < 0.001). The AD cohort also had a longer mean length of stay (P < 0.001). A greater proportion of patients in the AD cohort had nonroutine discharges (P = 0.039) and unplanned 30-day readmission (P = 0.041). On multivariate analysis, AD was significantly associated with increased cost (odds ratio: 1.61, P < 0.001) and nonroutine discharge (odds ratio: 1.36, P = 0.035). CONCLUSIONS: ADs may be associated with increased inpatient opioid consumption and healthcare resource utilization.

Association of inpatient opioid consumption on postoperative outcomes after open posterior spinal fusion for adult spine deformity.

INTRODUCTION: Opioids are the most commonly used analgesic in the postoperative setting. However, few studies have analyzed the impact of high inpatient opioid use on outcomes following surgery, with no current studies assessing its effect on patients undergoing spinal fusion for an adult spinal deformity (ASD). Thus, the aim of this study was to investigate risk factors for high inpatient opioid use, as well as to determine the impact of high opioid use on outcomes such as adverse events (AEs), hospital length of stay (LOS), cost of hospital admission, discharge disposition, and readmission rates in patients undergoing spinal fusion for ASD. METHODS: A retrospective cohort study was performed using the Premier healthcare database from the years 2016 and 2017. All adult patients > 40 years old who underwent thoracic or thoracolumbar fusion for ASD were identified using the ICD-10-CM diagnostic and procedural coding system. Patients were then categorized into three cohorts based on inpatient opioid use: Low MME (morphine milligram equivalents), Medium MME, and High MME. Patient demographics, comorbidities, treating hospital characteristics, intraoperative variables, postoperative AEs, LOS, discharge disposition, and total cost of hospital admission were assessed in the analysis. Multivariate regression analysis was done to determine independent predictors of high inpatient MME, prolonged LOS, and increased hospital cost. RESULTS: Of 1673 patients included, 417 (24.9%) were classified as Low MME, 840 (50.2%) as Medium MME, and 416 (24.9%) as High MME. Age significantly decreased with increasing MME (Low: 71.0% 65 + years vs Medium: 62.0% 65 + years vs High: 47.4% 65 + years, p < 0.001), while the proportions of patients presenting with three or more comorbidities were similar across the cohorts (Low: 20.1% with 3 + comorbidities vs Medium: 18.0% with 3 + comorbidities vs High: 24.3% with 3 + comorbidities, p = 0.070). With respect to postoperative outcomes, the proportion of patients who experienced any AE (Low: 60.2% vs Medium: 68.8% vs High: 70.9%, p = 0.002), extended LOS (Low: 6.7% vs Medium: 20.7% vs High: 45.4%, p < 0.001), or non-routine discharge (Low: 66.6% vs Medium: 73.5% vs High: 80.1%, p = 0.003) each increased along with total MME. In addition, rates of 30-day readmission were greatest among the High MME cohort (Low: 8.4% vs Medium: 7.9% vs High: 12.5%, p = 0.022). On multivariate analysis, medium and high MME were associated with prolonged LOS [Medium: OR 4.41, CI (2.90, 6.97); High: OR 13.99, CI (8.99, 22.51), p < 0.001] and increased hospital cost [Medium: OR 1.69, CI (1.21, 2.39), p = 0.002; High: OR 1.66, CI (1.12, 2.46), p = 0.011]. Preadmission long-term opioid use [OR 1.71, CI (1.07, 2.7), p = 0.022], a prior opioid-related disorder [OR 11.32, CI (5.92, 23.49), p < 0.001], and chronic pulmonary disease [OR 1.39, CI (1.06, 1.82), p = 0.018] were each associated with a high inpatient MME on multivariate analysis. CONCLUSION: Our study demonstrated that increasing inpatient MME consumption was associated with extended LOS and increased hospital cost in patients undergoing spinal fusion for ASD. Further studies identifying risk factors for increased MME consumption may provide better risk stratification for postoperative opioid use and healthcare resource utilization.

Feasibility, safety, and efficacy of circumferential spine stereotactic body radiotherapy.

Background: With advances in systemic therapy translating to improved survival in metastatic malignancies, spine metastases have become an increasingly common source of morbidity. Achieving durable local control (LC) for patients with circumferential epidural disease can be particularly challenging. Circumferential stereotactic body radiotherapy (SBRT) may offer improved LC for circumferential vertebral and/or epidural metastatic spinal disease, but prospective (and retrospective) data are extremely limited. We sought to evaluate the feasibility, toxicity, and cancer control outcomes with this novel approach to circumferential spinal disease. Methods: We retrospectively identified all circumferential SBRT courses delivered between 2013 and 2019 at a tertiary care institution for post-operative or intact spine metastases. Radiotherapy was delivered to 14-27.5 Gy in one to five fractions. Feasibility was assessed by determining the proportion of plans for which ≥95% planning target volume (PTV) was coverable by ≥95% prescription dose. The primary endpoint was 1-year LC. Factors associated with increased likelihood of local failure (LF) were explored. Acute and chronic toxicity were assessed. Detailed dosimetric data were collected. Results: Fifty-eight patients receiving 64 circumferential SBRT courses were identified (median age 61, KPS ≥70, 57% men). With a median follow-up of 15 months, the 12-month local control was 85% (eight events). Five and three recurrences were in the epidural space and bone, respectively. On multivariate analysis, increased PTV and uncontrolled systemic disease were significantly associated with an increased likelihood of LF; ≥95% PTV was covered by ≥95% prescription dose in 94% of the cases. The rate of new or progressive vertebral compression fracture was 8%. There were no myelitis events or any grade 3+ acute or late toxicities. Conclusions: For patients with circumferential disease, circumferential spine SBRT is feasible and may offer excellent LC without significant toxicity. A prospective evaluation of this approach is warranted.

Utilization of Machine Learning to Model Important Features of 30-day Readmissions following Surgery for Metastatic Spinal Column Tumors: The Influence of Frailty.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The aim of this study was to determine the relative importance and predicative power of the Hospital Frailty Risk Score (HFRS) on unplanned 30-day readmission after surgical intervention for metastatic spinal column tumors. METHODS: All adult patients undergoing surgery for metastatic spinal column tumor were identified in the Nationwide Readmission Database from the years 2016 to 2018. Patients were categorized into 3 cohorts based on the criteria of the HFRS: Low(<5), Intermediate(5-14.9), and High(≥ 15). Random Forest (RF) classification was used to construct predictive models for 30-day patient readmission. Model performance was examined using the area under the receiver operating curve (AUC), and the Mean Decrease Gini (MDG) metric was used to quantify and rank features by relative importance. RESULTS: There were 4346 patients included. The proportion of patients who required any readmission were higher among the Intermediate and High frailty cohorts when compared to the Low frailty cohort (Low:33.9% vs. Intermediate:39.3% vs. High:39.2%, P < .001). An RF classifier was trained to predict 30-day readmission on all features (AUC = .60) and architecturally equivalent model trained using only ten features with highest MDG (AUC = .59). Both models found frailty to have the highest importance in predicting risk of readmission. On multivariate regression analysis, Intermediate frailty [OR:1.32, CI(1.06,1.64), P = .012] was found to be an independent predictor of unplanned 30-day readmission. CONCLUSION: Our study utilizes machine learning approaches and predictive modeling to identify frailty as a significant risk-factor that contributes to unplanned 30-day readmission after spine surgery for metastatic spinal column metastases.

Assessment of Frailty Indices and Charlson Comorbidity Index for Predicting Adverse Outcomes in Patients Undergoing Surgery for Spine Metastases: A National Database Analysis.

OBJECTIVE: The aim of this study was to assess the predictive ability of Metastatic Spinal Tumor Frailty Index (MSTFI) and the Modified 5-Item Frailty Index (mFI-5) on adverse outcomes, compared with the known Charlson Comorbidity Index (CCI). METHODS: A retrospective cohort study was performed using National Surgical Quality Improvement Program database from 2011 to 2019. All adult patients undergoing various procedures for extradural spinal metastases were identified. Patients were stratified into frail and nonfrail cohorts based on CCI, mFI-5, and MSTFI scores. A multivariate logistic regression analysis was used to identify independent predictors of prolonged length of stay, nonroutine discharge, adverse events, and unplanned readmission. RESULTS: Of the 1613 patients included in this study, 21.4% had a CCI >0, 56.6% had an mFI-5 >0, and 76.7% of patients had an MSTFI >0. On multivariate analysis, all 3 indices were found to be predictive of nonroutine discharge (CCI: adjusted odds ratio [aOR], 1.41 vs. mFI-5: aOR, 1.37 vs. MSTFI: aOR, 1.5) and adverse events (CCI: aOR, 1.53 vs. mFI-5: aOR, 1.23 vs. MSTFI: aOR, 1.43). High CCI (adjusted relative risk, 1.67) and MSTFI (adjusted relative risk, 1.14), but not mFI-5, were also associated with a prolonged length of stay, whereas MSTFI was found to be the only significant predictor of unplanned readmission (aOR, 1.22). CONCLUSIONS: Our study suggests that MSTFI frailty index may be more sensitive than both CCI and mFI-5 in identifying adverse outcomes after spine surgery for metastases.

Spine Stereotactic Body Radiotherapy to Three or More Contiguous Vertebral Levels.

Background: With survival improving in many metastatic malignancies, spine metastases have increasingly become a source of significant morbidity; achieving durable local control (LC) is critical. Stereotactic body radiotherapy (SBRT) may offer improved LC and/or symptom palliation. However, due to setup concerns, SBRT is infrequently offered to patients with ≥3 contiguous involved levels. Because data are limited, we sought to evaluate the feasibility, toxicity, and cancer control outcomes of spine SBRT delivered to ≥3 contiguous levels. Methods: We retrospectively identified all SBRT courses delivered between 2013 and 2019 at a tertiary care institution for postoperative or intact spine metastases. Radiotherapy was delivered to 14-35 Gy in 1-5 fractions. Patients were stratified by whether they received SBRT to 1-2 or ≥3 contiguous levels. The primary endpoint was 1-year LC and was compared between groups. Factors associated with increased likelihood of local failure (LF) were explored. Acute and chronic toxicity was assessed. In-depth dosimetric data were collected. Results: Overall, 165 patients with 194 SBRT courses were identified [54% were men, median age was 61 years, 93% had Karnofsky Performance Status (KPS) ≥70, and median follow-up was 15 months]. One hundred thirteen patients (68%) received treatment to 1-2 and 52 to 3-7 (32%) levels. The 1-year LC was 88% (89% for 1-2 levels vs. 84% for ≥3 levels, p = 0.747). On multivariate analysis, uncontrolled systemic disease was associated with inferior LC for patients with ≥3 treated levels. No other demographic, disease, treatment, or dosimetric variables achieved significance. Rates of new/progressive fracture were equivalent (8% vs. 9.5%, p = 0.839). There were no radiation-induced myelopathy or grade 3+ acute or late toxicities in either group. Coverage of ≥95% of the planning target volume with ≥95% prescription dose was similar between groups (96% 1-2 levels vs. 89% ≥3 levels, p = 0.078). Conclusions: For patients with ≥3 contiguous involved levels, spine SBRT is feasible and may offer excellent LC without significant toxicity. Prospective evaluation is warranted.

Toward an artificial intelligence-assisted framework for reconstructing the digital twin of vertebra and predicting its fracture response.

This article presents an effort toward building an artificial intelligence (AI) assisted framework, coined ReconGAN, for creating a realistic digital twin of the human vertebra and predicting the risk of vertebral fracture (VF). ReconGAN consists of a deep convolutional generative adversarial network (DCGAN), image-processing steps, and finite element (FE) based shape optimization to reconstruct the vertebra model. This DCGAN model is trained using a set of quantitative micro-computed tomography (micro-QCT) images of the trabecular bone obtained from cadaveric samples. The quality of synthetic trabecular models generated using DCGAN are verified by comparing a set of its statistical microstructural descriptors with those of the imaging data. The synthesized trabecular microstructure is then infused into the vertebra cortical shell extracted from the patient's diagnostic CT scans using an FE-based shape optimization approach to achieve a smooth transition between trabecular to cortical regions. The final geometrical model of the vertebra is converted into a high-fidelity FE model to simulate the VF response using a continuum damage model under compression and flexion loading conditions. A feasibility study is presented to demonstrate the applicability of digital twins generated using this AI-assisted framework to predict the risk of VF in a cancer patient with spinal metastasis.

A digital twin for simulating the vertebroplasty procedure and its impact on mechanical stability of vertebra in cancer patients.

We present the application of ReconGAN, introduced in a previous study, for simulating the vertebroplasty (VP) operation and its impact on the fracture response of a vertebral body. ReconGAN consists of a Deep Convolutional Generative Adversarial Network (DCGAN) and a finite element based shape optimization algorithm to virtually reconstruct the trabecular bone microstructure. The VP procedure involves injecting shear-thinning liquid bone cement through a needle in the trabecular region to reinforce a diseased or fractured vertebra. To simulate this treatment modality, computational fluid dynamics (CFD) is employed to predict the morphology of the injected cement within the bone microstructure. A power-law equation is utilized to characterize the non-Newtonian shear-thinning behavior of the polymethyl methacrylate (PMMA) bone cement during injection simulations. The CFD model is coupled with the level-set method to simulate the motion of the interface separating bone cement and bone marrow. After predicting the cement morphology, a data co-registration algorithm is employed to transform the CFD model to a high-fidelity continuum damage mechanics (CDM) finite element model of the augmented vertebra for predicting the fracture response. A feasibility study is presented to demonstrate the ability of this CFD-CDM framework to investigate the effect of VP on the mechanical integrity of the vertebral body in a cancer patient with a lytic metastatic tumor.

Differences in Health Care Resource Utilization After Surgery for Metastatic Spinal Column Tumors in Patients with a Concurrent Affective Disorder in the United States.

BACKGROUND: Affective disorders, such as depression and anxiety, are exceedingly common among patients with metastatic cancer. The aim of this study was to investigate the relationship between affective disorders and health care resource utilization in patients undergoing surgery for a spinal column metastasis. METHODS: A retrospective cohort study was performed using the 2016-2018 National Inpatient Sample database. All adult patients (≥18 years) undergoing surgery for a metastatic spinal tumor were identified using the International Classification of Diseases, Tenth Revision, Clinical Modification coding systems. Patients were categorized into 2 cohorts: no affective disorder (No-AD) and affective disorder (AD). Patient demographics, comorbidities, hospital characteristics, intraoperative variables, postoperative adverse events (AEs), length of stay (LOS), discharge disposition, and total cost of hospital admission were assessed. A multivariate logistic regression analysis was used to identify independent predictors of increased cost, nonroutine discharge, and prolonged LOS. RESULTS: Of the 8360 patients identified, 1710 (20.5%) had a diagnosis of AD. Although no difference was observed in the rates of postoperative AEs between the cohorts (P = 0.912), the AD cohort had a significantly longer mean LOS (No-AD, 10.1 ± 8.3 days vs. AD, 11.6 ± 9.8 days; P = 0.012) and greater total cost (No-AD, $53,165 ± 35,512 vs. AD, $59,282 ± 36,917; P = 0.011). No significant differences in nonroutine discharge were observed between the cohorts (P = 0.265). On multivariate regression analysis, having an affective disorder was a significant predictor of increased costs (odds ratio, 1.45; confidence interval, 1.03-2.05; P = 0.034) and nonroutine discharge (odds ratio, 1.40; confidence interval, 1.06-1.85; P = 0.017), but not prolonged LOS (P = 0.067). CONCLUSIONS: Our study found that affective disorders were significantly associated with greater hospital expenditures and nonroutine discharge, but not prolonged LOS, for patients undergoing surgery for spinal metastases.

Cost Analysis With Use of Expandable Cage or Cement in Single level Thoracic Vertebrectomy in Metastasis.

STUDY DESIGN: Retrospective case series. OBJECTIVE: Patient with metastatic cancer frequently require spinal operations for neural decompression and stabilization, most commonly thoracic vertebrectomy with reconstruction. Objective of the study was to assess economic aspects associated with use of cement versus expandable cage in patients with single level thoracic metastatic disease. We also looked at the differences in the clinical, radiological, complications and survival differences to assess non-inferiority of PMMA over cages. METHODS: The electronic medical records of patients undergoing single level thoracic vertebrectomy and reconstruction were reviewed. Two groups were made: PMMA and EC. Totals surgical cost, implant costs was analyzed. We also looked at the clinical/ radiological outcome, complication and survival analysis. RESULTS: 96 patients were identified including 70 one-level resections. For 1-level surgeries, Implant costs for use of cement-$75 compared to $9000 for cages. Overall surgical cost was significantly less for PMMA compared to use of EC. No difference was seen in clinical outcome or complication was seen. We noticed significantly better kyphosis correction in the PMMA group. CONCLUSIONS: Polymethylmethacrylate cement offers significant cost advantage for reconstruction after thoracic vertebrectomy. It also allows for better kyphosis correction and comparable clinical outcomes and non-inferior to cages.

Overview of the management of primary tumors of the spine.

STUDY DESIGN: Narrative review. OBJECTIVE: To provide a narrative review for diagnosis and management of Primary spine tumors. METHODS: A detailed review of literature was done to identify relevant and well cited manuscripts to construct this narrative review. RESULTS: Primary tumors of the spine are rare with some racial differences reported. There are numerous adjuvant technologies and developments that influence the way we currently manage these tumors. Collimated radiation allows for heavy dosage to be delivered and have been reported to give good local control both as an adjuvant and neoadjuvant setting. These have made surgical decision making even more intricate needing a multicentric approach. Dedicated care has been shown to significantly improve health quality of life measures and survival. CONCLUSION: While, it is beyond the scope of this paper to discuss all primary tumors subtypes individually, this review highlights the developments and approach to primary spine tumors.

Postoperative Stereotactic Body Radiotherapy for Spinal Metastasis and Predictors of Local Control.

BACKGROUND: Spine surgery is indicated for select patients with mechanical instability, pain, and/or malignant epidural spinal cord compression, with or without neurological compromise. Stereotactic body radiotherapy (SBRT) is an option for durable local control (LC) for metastatic spine disease. OBJECTIVE: To determine factors associated with LC and progression-free survival (PFS) for patients receiving postoperative stereotactic spine radiosurgery. METHODS: We analyzed consecutive patients from 2013 to 2019 treated with surgical intervention followed by SBRT. Surgical interventions included laminectomy and vertebrectomy. SBRT included patients treated with 1 to 5 fractions of radiosurgery. We analyzed LC, PFS, overall survival (OS), and toxicity. Univariate and multivariate analyses were performed. RESULTS: A total of 63 patients were treated with a median follow-up of 12.5 mo. Approximately 75% of patients underwent vertebrectomy and 25% underwent laminectomy. One-year cumulative incidence of local failure was 19%. LC was significantly improved for patients receiving radiosurgery ≤40 d from surgery compared to that for patients receiving radiosurgery ≥40 d from surgery, 94% vs 75%, respectively, at 1 yr (P = .03). Patients who received preoperative embolization had improved LC with 1-yr LC of 88% vs 76% for those who did not receive preoperative embolization (P = .037). Significant predictors for LC on multivariate analysis were time from surgery to radiosurgery, higher radiotherapy dose, and preoperative embolization. The 1-yr PFS and OS was 56% and 60%, respectively. CONCLUSION: Postoperative radiosurgery has excellent and durable LC for spine metastasis. An important consideration when planning postoperative radiosurgery is minimizing delay from surgery to radiosurgery. Preoperative embolization and higher radiotherapy dose were associated with improved LC warranting further study.

Damned if you monitor, damned if you don't: medical malpractice and intraoperative neuromonitoring for spinal surgery.

OBJECTIVE: The aim of this study was to identify trends in medical malpractice litigation related to intraoperative neuromonitoring. METHODS: The Westlaw Edge legal research service was queried for malpractice litigation related to neuromonitoring in spine surgery. Cases were reviewed to determine if the plaintiff's assertion of negligence was due to either failure to use neuromonitoring or negligent monitoring. Comparative statistics and a detailed qualitative analysis of the resulting cases were performed. RESULTS: Twenty-six cases related to neuromonitoring were identified. Spinal fusion was the procedure in question in all cases, and defendants were nearly evenly divided between orthopedic surgeons and neurosurgeons. Defense verdicts were most common (54%), followed by settlements (27%) and plaintiff verdicts (19%). Settlements resulted in a mean $7,575,000 damage award, while plaintiff verdicts resulted in a mean $4,180,213 damage award. The basis for litigation was failure to monitor in 54% of the cases and negligent monitoring in 46%. There were no significant differences in case outcomes between the two allegations of negligence. CONCLUSIONS: The use and interpretation of intraoperative neuromonitoring findings can be the basis for a medical malpractice litigation. Spine surgeons can face malpractice risks by not monitoring when required by the standard of care and by interpreting or reacting to neuromonitoring findings inappropriately.