Development of a Novel Risk Stratification Score to Predict 30-Day Mortality in Cervical Trauma Patients: CLAAD Score.

STUDY DESIGN: Case control. OBJECTIVE: Traumatic cervical spine injuries are associated with a substantial risk of mortality. The aim of this study is to develop a novel mortality prediction model for patients with cervical trauma who require operative treatment. SUMMARY OF BACKGROUND DATA: Patients with cervical spine trauma have a high risk of postoperative complications and mortality. There are few reliable systems that can accurately predict mortality after surgery for cervical spine trauma, and those that do exist are typically not specific to cervical trauma. MATERIALS AND METHODS: The National Surgical Quality Improvement Program (NSQIP) database was used to identify patients undergoing surgery for cervical spine trauma. Univariate analyses were performed to identify variables associated with mortality. Variables that were found to be significant in the univariate models were compiled into a multivariable model. The final model was compared with the American Society of Anesthesiologists (ASA), a modified Charlson comorbidity index (mCCI), and the 5-factor modified frailty index (mFI-5) in respect to predicting 30-day mortality after cervical trauma. The score was then externally validated using the Nationwide Inpatient Sample (NIS) database. RESULTS: Fifty-five (6.7%) of 822 patients did not survive 30 days after surgery. The final multivariable logistic regression model consisted of the following variables: circumferential fusion "C." long "L" fusion (more than 4 levels), anemia "A," age over 60 "A," and dialysis "D." The risk of mortality increased with increasing CLAAD score, with mortality rates of 0.9%, 3.1%, 7.4%, 22.7%, and 14.3% for scores of 0, 1, 2, 3, and 4, respectively. The CLAAD model had an AUC of 0.73 for predicting mortality after cervical trauma. CONCLUSIONS: The CLAAD score is a simple and effective system that can help identify patients at risk of increased mortality within 30 days of cervical trauma. LEVEL OF EVIDENCE: Level III.

The cost-utility of intraoperative tranexamic acid in adult spinal deformity patients undergoing long posterior spinal fusion.

PURPOSE: This study aims to evaluate the cost-utility of intraoperative tranexamic acid (TXA) in adult spinal deformity (ASD) patients undergoing long posterior (≥ 5 vertebral levels) spinal fusion. METHODS: A decision-analysis model was built for a hypothetical 60-year-old adult patient with spinal deformity undergoing long posterior spinal fusion. A comprehensive review of the literature was performed to obtain event probabilities, costs and health utilities at each node. Health utilities were utilized to calculate Quality-Adjusted Life Years (QALYs). A base-case analysis was carried out to obtain the incremental cost and effectiveness of intraoperative TXA. Probabilistic sensitivity analysis was performed to evaluate uncertainty in our model and obtain mean incremental costs, effectiveness, and net monetary benefits. One-way sensitivity analyses were also performed to identify the variables with the most impact on our model. RESULTS: Use of intraoperative TXA was the favored strategy in 88% of the iterations. The mean incremental utility ratio for using intraoperative TXA demonstrated higher benefit and lower cost while being lower than the willingness-to-pay threshold set at $50,000 per quality adjusted life years. Use of intraoperative TXA was associated with a mean incremental net monetary benefit (INMB) of $3743 (95% CI 3492-3995). One-way sensitivity analysis reported cost of blood transfusions due to post-operative anemia to be a major driver of cost-utility analysis. CONCLUSION: Use of intraoperative TXAs is a cost-effective strategy to reduce overall perioperative costs related to post-operative blood transfusions. Administration of intraoperative TXA should be considered for long fusions in ASD population when not explicitly contra-indicated due to patient factors.

Life Expectancy After Treatment of Metastatic Bone Disease: An International Trend Analysis.

INTRODUCTION: The decision to treat metastatic bone disease (MBD) surgically depends in part on patient life expectancy. We are unaware of an international analysis of how life expectancy among these patients has changed over time. Therefore, we asked (1) how has the life expectancy for patients treated for MBD changed over time, and (2) which, if any, of the common primary cancer types are associated with longer survival after treatment of MBD? METHODS: We reviewed data collected from 2000 to 2022 in an international MBD database, as well as data used for survival model validation. We included 3,353 adults who underwent surgery and/or radiation. No patients were excluded. Patients were grouped by treatment date into period 1 (2000 to 2009), period 2 (2010 to 2019), and period 3 (2020 to 2022). Cumulative survival was portrayed using Kaplan-Meier curves; log-rank tests were used to determine significance at P < 0.05. Subgroup analyses by primary cancer diagnosis were performed. RESULTS: Median survival in period 2 was longer than in period 1 ( P < 0.001). Median survival (at which point 50% of patients survived) had not been reached for period 3. Median survival was longer in period 2 for all cancer types ( P < 0.001) except thyroid. Only lung cancer reached median survival in period 3, which was longer compared with periods 1 and 2 ( P < 0.001). Slow-growth, moderate-growth, and rapid-growth tumors all demonstrated longer median survival from period 1 to period 2; only rapid-growth tumors reached median survival for period 3, which was longer compared with periods 1 and 2 ( P < 0.001). DISCUSSION: Median duration of survival after treatment of MBD has increased, which was a consistent finding in nearly all cancer types. Longer survival is likely attributable to improvements in both medical and surgical treatments. As life expectancy for patients with MBD increases, surgical methods should be selected with this in mind. LEVEL OF EVIDENCE: VI.

Concomitant Traumatic Brain Injury Delays Surgery in Patients With Traumatic Spinal Cord Injury.

BACKGROUND AND OBJECTIVES: Growing evidence supports prompt surgical decompression for patients with traumatic spinal cord injury (tSCI). Rates of concomitant tSCI and traumatic brain injury (TBI) range from 10% to 30%. Concomitant TBI may delay tSCI diagnosis and surgical intervention. Little is known about real-world management of this common injury constellation that carries significant clinical consequences. This study aimed to quantify the impact of concomitant TBI on surgical timing in a national cohort of patients with tSCI. METHODS: Patient data were obtained from the National Trauma Data Bank (2007-2016). Patients admitted for tSCI and who received surgical intervention were included. Delayed surgical intervention was defined as surgery after 24 hours of admission. Multivariable hierarchical regression models were constructed to measure the risk-adjusted association between concomitant TBI and delayed surgical intervention. Secondary outcome included favorable discharge status. RESULTS: We identified 14 964 patients with surgically managed tSCI across 377 North American trauma centers, of whom 2444 (16.3%) had concomitant TBI and 4610 (30.8%) had central cord syndrome (CCS). The median time to surgery was 20.0 hours for patients without concomitant TBI and 24.8 hours for patients with concomitant TBI. Hierarchical regression modeling revealed that concomitant TBI was independently associated with delayed surgery in patients with tSCI (odds ratio [OR], 1.3; 95% CI, 1.1-1.6). Although CCS was associated with delayed surgery (OR, 1.5; 95% CI, 1.4-1.7), we did not observe a significant interaction between concomitant TBI and CCS. In the subset of patients with concomitant tSCI and TBI, patients with severe TBI were significantly more likely to experience a surgical delay than patients with mild TBI (OR, 1.4; 95% CI, 1.0-1.9). CONCLUSION: Concomitant TBI delays surgical management for patients with tSCI. This effect is largest for patients with tSCI with severe TBI. These findings should serve to increase awareness of concomitant TBI and tSCI and the likelihood that this may delay time-sensitive surgery.

Open Access Publication in Total Knee Arthroplasty Is Associated With Increased Social Media Attention, but Is Not Associated With Increased Citations.

BACKGROUND: Open access (OA) publication is growing in total joint arthroplasty literature. While OA manuscripts are free to view, these publications require a fee from authors. This study aimed to compare social media attention and citation rates between OA and non-OA publications in the total knee arthroplasty (TKA) literature. METHODS: There were 9,606 publications included, with 4,669 (48.61%) as OA articles. The TKA articles were identified from 2016 to 2022. Articles were grouped as OA or non-OA and Altmetric Attention Score (AAS), a weighted count of social media attention, and the Mendeley readership were analyzed using negative binomial regressions while adjusting for days since publication. RESULTS: The OA articles had greater mean AAS (13.45 versus 8.42, P = .012) and Mendeley readership (43.91 versus 36.72, P < .001). OA was not an independent predictor of number of citations when compared to non-OA articles (13.98 versus 13.63, P = .914). Subgroup analysis of studies in the top 10 arthroplasty journals showed OA was not an independent predictor of AAS (13.51 versus 9.53, P = .084) or number of citations (19.51 versus 18.74, P = .495) but was an independent predictor of Mendeley readership (49.05 versus 40.25, P < .003). CONCLUSION: The OA publications in the TKA literature were associated with increased social media attention, but not overall citations. This association was not observed among the top 10 journals. Authors may use these results to weigh the relative importance of readership, citations, and online engagement to the cost of OA publication.

Inflation-adjusted medicare physician reimbursement for adult spinal deformity surgery substantially declined from 2002 to 2020.

PURPOSE: Physician fees for orthopaedic surgeons by the Centers for Medicare and Medicaid Services (CMS) are increasingly scrutinized. The present retrospective review aims to assess whether adult spinal deformity (ASD) surgeries are properly valued for Medicare reimbursement. METHODS: Current Procedural Terminology (CPT) codes related to posterior fusion of spinal deformity of ≤ 6, 7-12, and ≥ 13 vertebral levels, as well as additional arthrodesis and osteotomy levels, were assessed for (1) Compound annual growth rate (CAGR) from 2002 to 2020, calculated using physician fee data from the CMS Physician Fee Schedule Look-Up Tool; and (2) work relative value units (RVUs) per operative minute, using data from the National Surgical Quality Improvement Program. RESULTS: From 2002 to 2020, all CPT codes for ASD surgery had negative inflation-adjusted CAGRs (range, - 18.49% to - 27.66%). Mean physician fees for spinal fusion declined by 26.02% (CAGR, - 1.66%) in ≤ 6-level fusion, 27.91% (CAGR, - 1.80%) in 7- to 12-level fusion, and 28.25% (CAGR, - 1.83%) ≥ 13-level fusion. Fees for both 7-12 (P < 0.00001) and ≥ 13 levels (P < 0.00001) declined more than those for fusion of ≤ 6 vertebral levels. RVU per minute was lower for 7- to 12-level and ≥ 13-level (P < 0.00001 for both) ASD surgeries than for ≤ 6-level. CONCLUSIONS: Reimbursement for ASD surgery declined overall. CAGR for fusions of ≥ 7 levels were lower than those for fusions of ≤ 6 levels. For 2012-2018, ≥ 7-level fusions had lower RVU per minute than ≤ 6-level fusions. Revaluation of Medicare reimbursement for longer-level ASD surgeries may be warranted. LEVEL OF EVIDENCE: III.

Predicting Risk of 30-day Postoperative Morbidity Using the Pathologic Fracture Mortality Index.

INTRODUCTION: The purpose of this study was to evaluate the ability of the Pathologic Fracture Mortality Index (PFMI) to predict the risk of 30-day morbidity after pathologic fracture fixation and compare its efficacy with those of the American Society of Anesthesiologists (ASA) physical status, modified Charlson Comorbidity Index (mCCI), and modified frailty index (mFI-5). METHODS: Cohorts of 1,723 patients in the American College of Surgeons National Surgical Quality Improvement Program database from 2005 to 2020 and 159 patients from a tertiary cancer referral center who underwent fixation for impending or completed pathologic fractures of long bones were retrospectively analyzed. National Surgical Quality Improvement Program morbidity variables were categorized into medical, surgical, utilization, and all-cause. PFMI, ASA, mCCI, and mFI-5 scores were calculated for each patient. Area under the curve (AUC) was used to compare efficacies. RESULTS: AUCs predicting all-cause morbidity were 0.62, 0.54, and 0.56 for the PFMI, ASA, and mFI-5, respectively. The PFMI outperformed the ASA and mFI-5 in predicting all-cause ( P < 0.01), medical ( P = 0.01), and utilization ( P < 0.01) morbidities. In the 2005 to 2012 subset, the PFMI outperformed the ASA, mFI-5, and mCCI in predicting all-cause ( P = 0.01), medical ( P = 0.03), and surgical ( P = 0.05) morbidities but performed similarly to utilization morbidity ( P = 0.19). In our institutional cohort, the AUC for the PFMI in morbidity stratification was 0.68. The PFMI was associated with all-cause (odds ratio [OR], 1.30; 95% confidence interval [CI], 1.12 to 1.51; P < 0.001), medical (OR, 1.19; 95% CI, 1.03 to 1.40; P = 0.046), and utilization (OR, 1.32; 95% CI, 1.14 to 1.52; P < 0.001) morbidities but not significantly associated with surgical morbidity (OR, 1.21; 95% CI, 0.98 to 1.49; P = 0.08) in this cohort. DISCUSSION: The PFMI is an advancement in postoperative morbidity risk stratification of patients with pathologic fracture from metastatic disease. LEVEL OF EVIDENCE: III.

Predicting Mortality Following Odontoid Fracture Fixation in Elderly Patients: CAADS-16 Score.

STUDY DESIGN: Retrospective Review of a National Database. INTRODUCTION: By utilizing a national database, this study aims to quantify the predictors of 30-day mortality after odontoid fixation and guide appropriate management for patients in whom the choice between operative and non-operative management is unclear. METHODS: The American College of Surgeons National Surgical Quality Improvement Database was queried using Current Procedural Terminology (CPT) codes and International Classification of Disease (ICD) codes to identify patients 60 or older who underwent surgical fixation of an odontoid fracture from 2005 to 2020. Risk factors for mortality significant in univariate and subsequent multivariate analysis were used to develop a scoring system to predict post-operative mortality. RESULTS: 608 patients were identified. Patients were split into a non-mortality 30 days post-op group, and into a mortality 30 days post-op group. The following risk factors were included in the scoring system: functional dependency, disseminated cancer, albumin less than 3.5, WBC count greater than 16 k, anterior surgical approach, and pre-op SIRS. Using a cutoff value of 2, the CAAD-16 score had a sensitivity and specificity of 82% and 81%, respectively. The ASA score, cutoff at 4, showed a sensitivity and specificity of 64% and 75% respectively. CONCLUSIONS: This sample of 294 patients represents one of the largest samples of odontoid fracture fixation patients available in the literature and comes from a nationally representative database. We structure relevant risk factors into the CAADS-16 score, which has the potential to be a clinically relevant tool to prevent short-term postoperative mortality.

Association of Neighborhood Socioeconomic Deprivation With Utilization and Costs of Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: A retrospective analysis. OBJECTIVE: The aim of our study was to analyze the association of Area Deprivation Index (ADI) with the utilization and costs of elective anterior cervical discectomy and fusion (ACDF) surgery. SUMMARY OF BACKGROUND DATA: ADI, a comprehensive neighborhood-level measure of socioeconomic disadvantage, has been shown to be associated with worse perioperative outcomes in a variety of surgical settings. MATERIALS AND METHODS: The Maryland Health Services Cost Review Commission Database was queried to identify patients who underwent primary elective ACDF between 2013 and 2020 in the state. Patients were stratified into tertiles by ADI, from least disadvantaged (ADI1) to most disadvantaged (ADI3). The primary endpoints were ACDF utilization rates per 100,000 adults and episode-of-care total costs. Univariable and multivariable regression analyses were performed. RESULTS: A total of 13,362 patients (4984 inpatient and 8378 outpatient) underwent primary ACDF during the study period. In our study, there were 2,401 (17.97%) patients residing in ADI1 neighborhoods (least deprived), 5974 (44.71%) in ADI2, and 4987 (37.32%) in ADI3 (most deprived). Factors associated with increased surgical utilization were increasing ADI, outpatient surgical setting, non-Hispanic ethnicity, current tobacco use, and diagnoses of obesity and gastroesophageal reflux disease. Factors associated with lower surgical utilization were: non-white race, rurality, Medicare/Medicaid insurance status, and diagnoses of cervical disk herniation or myelopathy. Factors associated with higher costs of care were increasing ADI, older age, Black/African American race, Medicare or Medicaid insurance, former tobacco use, and diagnoses of ischemic heart disease and cervical myelopathy. Factors associated with lower costs of care were outpatient surgical setting, female sex, and diagnoses of gastroesophageal reflux disease and cervical disk herniation. CONCLUSIONS: Neighborhood socioeconomic deprivation is associated with increased episode-of-care costs in patients undergoing ACDF surgery. Interestingly, we found greater utilization of ACDF surgery among patients with higher ADI. LEVEL OF EVIDENCE: 3.

The Statistical Fragility of Trials Comparing Cervical Disc Arthroplasty and Anterior Cervical Discectomy and Fusion: A Meta Analysis.

STUDY DESIGN: Meta-analysis. OBJECTIVE: Assess the robustness of randomized controlled trials (RCTs) that compared cervical disc arthroplasty (CDA) and anterior cervical discectomy and fusion (ACDF) for the treatment of symptomatic degenerative cervical pathology by using fragility indices. SUMMARY OF BACKGROUND DATA: RCTs comparing these surgical approaches have shown that CDA may be equivalent or even superior to ACDF due to better preservation of normal spinal kinematics. METHODS: RCTs reporting clinical outcomes after CDA versus ACDF for degenerative cervical disc disease were evaluated. Data for outcome measures were classified as continuous or dichotomous. Continuous outcomes included: Neck Disability Index (NDI), overall pain, neck pain, radicular arm pain, and modified Japanese Orthopaedic Association (mJOA) scores. Dichotomous outcomes included: any adjacent segment disease (ASD), superior-level ASD, and inferior-level ASD. The fragility index (FI) and continuous FI (CFI) were determined for dichotomous and continuous outcomes, respectively. The corresponding fragility quotient (FQ) and continuous FQ (CFQ) were calculated by dividing FI/CFI by sample size. RESULTS: Twenty-five studies (78 outcome events) were included. Thirteen dichotomous events had a median FI of 7 (IQR: 3-10) and the median FQ was 0.043 (IQR: 0.035-0.066). Sixty-five continuous events had a median CFI of 14 (IQR: 9-22) and median CFQ of 0.145 (IQR: 0.074-0.188). This indicates that, on average, altering the outcome of 4.3 patients out of 100 for the dichotomous outcomes, and 14.5 out of 100 for continuous outcomes, would reverse trial significance. Of the 13 dichotomous events that included lost to follow-up data, 8 (61.5%) represented ≥7 patients lost. Of the 65 continuous events reporting lost to follow-up data, 22 (33.8%) represented ≥14 patients lost. CONCLUSION: RCTs comparing ACDF and CDA have fair to moderate statistical robustness and do not suffer from statistical fragility.

Contemporary Trends in Minimally Invasive Sacroiliac Joint Fusion Utilization in the Medicare Population by Specialty.

BACKGROUND AND OBJECTIVES: Sacroiliac (SI) joint dysfunction constitutes a leading cause of pain and disability. Although surgical arthrodesis is traditionally performed under open approaches, the past decade has seen a rise in minimally invasive surgical (MIS) techniques and new federally approved devices for MIS approaches. In addition to neurosurgeons and orthopedic surgeons, proceduralists from nonsurgical specialties are performing MIS procedures for SI pathology. Here, we analyze trends in SI joint fusions performed by different provider groups, along with trends in the charges billed and reimbursement provided by Medicare. METHODS: We review yearly Physician/Supplier Procedure Summary data from 2015 to 2020 from the Centers for Medicare and Medicaid Services for all SI joint fusions. Patients were stratified as undergoing MIS or open procedures. Utilization was adjusted per million Medicare beneficiaries and weighted averages for charges and reimbursements were calculated, controlling for inflation. Reimbursement-to-charge (RCR) ratios were calculated, reflecting the proportion of provider billed amounts reimbursed by Medicare. RESULTS: A total of 12 978 SI joint fusion procedures were performed, with the majority (76.5%) being MIS procedures. Most MIS procedures were performed by nonsurgical specialists (52.1%) while most open fusions were performed by spine surgeons (71%). Rapid growth in MIS procedures was noted for all specialty categories, along with an increased number of procedures offered in the outpatient setting and ambulatory surgical centers. The overall RCR increased over time and was ultimately similar between spine surgeons (RCR = 0.26) and nonsurgeon specialists (RCR = 0.27) performing MIS procedures. CONCLUSION: Substantial growth in MIS procedures for SI pathology has occurred in recent years in the Medicare population. This growth can largely be attributed to adoption by nonsurgical specialists, whose reimbursement and RCR increased for MIS procedures. Future studies are warranted to better understand the impact of these trends on patient outcomes and costs.

Predicting 30-day mortality after surgery for metastatic disease of the spine: the H2-FAILS score.

PURPOSE: Scoring systems for metastatic spine disease focus on predicting long- to medium-term mortality or a combination of perioperative morbidity and mortality. However, accurate prediction of perioperative mortality alone may be the most important factor when considering surgical intervention. We aimed to develop and evaluate a new tool, the H2-FAILS score, to predict 30-day mortality after surgery for metastatic spine disease. METHODS: Using the National Surgical Quality Improvement Program database, we identified 1195 adults who underwent surgery for metastatic spine disease from 2010 to 2018. Incidence of 30-day mortality was 8.7% (n = 104). Independent predictors of 30-day mortality were used to derive the H2-FAILS score. H2-FAILS is an acronym for: Heart failure (2 points), Functional dependence, Albumin deficiency, International normalized ratio elevation, Leukocytosis, and Smoking (1 point each). Discrimination was assessed using area under the receiver operating characteristic curve (AUC). The H2-FAILS score was compared with the American Society of Anesthesiologists Physical Status Classification (ASA Class), the 5-item modified Frailty Index (mFI-5), and the New England Spinal Metastasis Score (NESMS). Internal validation was performed using bootstrapping. Alpha = 0.05. RESULTS: Predicted 30-day mortality was 1.8% for an H2-FAILS score of 0 and 78% for a score of 6. AUC of the H2-FAILS was 0.77 (95% confidence interval: 0.72-0.81), which was higher than the mFI-5 (AUC 0.58, p < 0.001), ASA Class (AUC 0.63, p < 0.001), and NESMS (AUC 0.70, p = 0.004). Internal validation showed an optimism-corrected AUC of 0.76. CONCLUSIONS: The H2-FAILS score accurately predicts 30-day mortality after surgery for spinal metastasis. LEVEL OF EVIDENCE: Prognostic level III.

Laminectomy vs Fusion for Intradural Extramedullary Tumors.

BACKGROUND: Laminectomy (LA) and LA with fusion (LAF) have been demonstrated as surgical techniques that treat intradural extramedullary tumors (IDEMTs). The purpose of the present study was to compare the rate of 30-day complications following LA vs LAF for IDEMTs. METHODS: Patients undergoing LA for IDEMTs from 2012 to 2018 were identified in the National Surgical Quality Improvement Program database. Patients undergoing LA for IDEMTs were substratified into 2 cohorts: those who received LAF and those who did not. In this analysis, preoperative patient characteristics and demographic variables were assessed. 30-day wound, sepsis, cardiac, pulmonary, renal, and thromboembolic complications, as well as mortality, postoperative transfusions, extended length of stay, and reoperation, were assessed. Bivariate analyses, including χ 2 and t tests, and multivariable logistical regression were performed. RESULTS: Of 2027 total patients undergoing LA for IDEMTs, 181 (9%) also had fusion. There were 72/373 (19%) LAF in the cervical region, 67/801 (8%) LAF in the thoracic region, and 42/776 (5%) LAF in the lumbar region. Following adjustment, patients who received LAF were more likely to have increased length of stay (OR 2.73, P < 0.001) and increased rate of postoperative transfusion (OR 3.15, P < 0.001). Patients undergoing LA in the cervical spine for IDEMTs tended to receive additional fusion (P < 0.001). CONCLUSIONS: Increased length of stay and rate of postoperative transfusion were associated with LAF for IDEMTs. LA in the cervical spine for IDEMTs was associated with additional fusion.

Comparing five equations to calculate estimated glomerular filtration rate to predict acute kidney injury following total joint arthroplasty.

BACKGROUND: Acute kidney injury (AKI) following total joint arthroplasty (TJA) is associated with increased morbidity and mortality. Estimated glomerular filtration rate (eGFR) is used as an indicator of renal function. The purpose of this study was (1) to assess each of the five equations that are used in calculating eGFR, and (2) to evaluate which equation may best predict AKI in patients following TJA. METHODS: The National Surgical Quality Improvement Program (NSQIP) was queried for all 497,261 cases of TJA performed from 2012 to 2019 with complete data. The Modification of Diet in Renal Disease (MDRD) II, re-expressed MDRD II, Cockcroft-Gault, Mayo quadratic, and Chronic Kidney Disease Epidemiology Collaboration equations were used to calculate preoperative eGFR. Two cohorts were created based on the development of postoperative AKI and were compared based on demographic and preoperative factors. Multivariate regression analysis was used to assess for independent associations between preoperative eGFR and postoperative renal failure for each equation. The Akaike information criterion (AIC) was used to evaluate predictive ability of the five equations. RESULTS: Seven hundred seventy-seven (0.16%) patients experienced AKI after TJA. The Cockcroft-Gault equation yielded the highest mean eGFR (98.6 ± 32.7), while the Re-expressed MDRD II equation yielded the lowest mean eGFR (75.1 ± 28.8). Multivariate regression analysis demonstrated that a decrease in preoperative eGFR was independently associated with an increased risk of developing postoperative AKI in all five equations. The AIC was the lowest in the Mayo equation. CONCLUSIONS: Preoperative decrease in eGFR was independently associated with increased risk of postoperative AKI in all five equations. The Mayo equation was most predictive of the development of postoperative AKI following TJA. The mayo equation best identified patients with the highest risk of postoperative AKI, which may help providers make decisions on perioperative management in these patients.

A Five-Year Cost-Utility Analysis Comparing Synthetic Cage Versus Allograft Use in Anterior Cervical Discectomy and Fusion Surgery for Cervical Spondylotic Myelopathy.

STUDY DESIGN: Retrospective cost-utility analysis. OBJECTIVE: To conduct a cost-analysis comparing synthetic cage (SC) versus allograft (Allo) over a five-year time horizon. SUMMARY OF BACKGROUND DATA: SC and Allo are two commonly used interbody choices for anterior cervical discectomy and fusion (ACDF) surgery. Previous analyses comparative analyses have reached mixed conclusions regarding their cost-effectiveness, yet recent estimates provide high-quality evidence. MATERIALS AND METHODS: A decision-analysis model comparing the use of Allo versus SC was developed for a hypothetical 60-year-old patient with cervical spondylotic myelopathy undergoing single-level ACDF surgery. A comprehensive literature review was performed to estimate probabilities, costs (2020 USD) and quality-adjusted life years (QALYs) gained over a five-year period. A probabilistic sensitivity analysis using a Monte Carlo simulation of 1000 patients was carried out to calculate incremental cost-effectiveness ratio and net monetary benefits. One-way deterministic sensitivity analysis was performed to estimate the contribution of individual parameters to uncertainty in the model. RESULTS: The use of Allo was favored in 81.6% of the iterations at a societal willing-to-pay threshold of 50,000 USD/QALY. Allo dominated (higher net QALYs and lower net costs) in 67.8% of the iterations. The incremental net monetary benefits in the Allo group was 2650 USD at a willing-to-pay threshold of 50,000 USD/QALY. One-way deterministic sensitivity analysis revealed that the cost of the index surgery was the only factor which significantly contributed to uncertainty. CONCLUSION: Cost-utility analysis suggests that Allo maybe a more cost-effective option compared with SCs in adult patients undergoing ACDF for cervical spondylotic myelopathy.

The "kickstand rod" technique for correction of coronal malalignment: two-year clinical and radiographic outcomes.

PURPOSE: Restoring coronal alignment in spine deformity patients has been shown to play an important role in improving patient reported outcomes (PRO). Recently, the "kickstand rod" (KSR) technique was developed as a novel coronal correction method in complex spine deformity cases. The goal of the present study was to assess outcomes of this technique at two years of follow-up. METHODS: Consecutive, unique adult patients who underwent KSR constructs for coronal spinal malalignment between 2015 and 2019 with a minimum 2 year clinical and radiographic follow-up were identified. A KSR construct includes a more laterally placed iliac screw and additional rod that effectively depresses the ipsilateral ilium/pelvis for coronal correction, while serving as a buttress to prevent future loss of correction. Outcomes included revision for instrumentation-related complications, radiographic alignment, and PROs. RESULTS: Twenty patients were included with a mean age of 54 years [range: 20-73 years]. Mean follow-up time was 2.5 years [range: 2.0-5.0]. Mean number of levels fused was 17.3 [range: 10-24]. There were significant improvements in coronal alignment (CVA: 5.8 cm ± 2.6 cm vs. 1.7 cm ± 1.5 cm), sagittal alignment (SVA: 5.6 cm ± 5.9 cm vs. 1.6 cm ± 2.5 cm) and major Cobb angle (55º ± 32 vs. 26º ± 21) maintained at 2 years (p < 0.05). One patient experienced an asymptomatic fracture at the shank of the KSR iliac screw. There were significant improvements in Oswestry Disability Index and SRS-22 domains (p < 0.05). CONCLUSION: The KSR technique is a safe and effective method for correcting coronal malalignment in complex spinal deformity patients with no revisions specific for the KSR or iliac screw and significantly improved PROs at a minimum two-year follow-up.

The BTK Safety Score: A Novel Scoring System for Risk Stratifying Patients Undergoing Simultaneous Bilateral Total Knee Arthroplasty.

Selection of appropriate candidates for simultaneous bilateral total knee arthroplasty (si-BTKA) is crucial for minimizing postoperative complications. The aim of this study was to develop a scoring system for identifying patients who may be appropriate for si-BTKA. Patients who underwent si-BTKA were identified in the National Surgical Quality Improvement Program database. Patients who experienced a major 30-day complication were identified as high-risk patients for si-BTKA who potentially would have benefitted from staged bilateral total knee arthroplasty. Major complications included deep wound infection, pneumonia, renal insufficiency or failure, cerebrovascular accident, cardiac arrest, myocardial infarction, pulmonary embolism, sepsis, or death. The predictive model was trained using randomly split 70% of the dataset and validated on the remaining 30%. The scoring system was compared against the American Society of Anesthesiologists (ASA) score, the Charlson Comorbidity Index (CCI), and legacy risk-stratification measures, using area under the curve (AUC) statistic. Total 4,630 patients undergoing si-BTKA were included in our cohort. In our model, patients are assigned points based on the following risk factors: +1 for age ≥ 75, +2 for age ≥ 82, +1 for body mass index (BMI) ≥ 34, +2 for BMI ≥ 42, +1 for hypertension requiring medication, +1 for pulmonary disease (chronic obstructive pulmonary disease or dyspnea), and +3 for end-stage renal disease. The scoring system exhibited an AUC of 0.816, which was significantly higher than the AUC of ASA (0.545; p < 0.001) and CCI (0.599; p < 0.001). The BTK Safety Score developed and validated in our study can be used by surgeons and perioperative teams to risk stratify patients undergoing si-BTKA. Future work is needed to assess this scoring system's ability to predict long-term functional outcomes.

Using Predictive Modeling and Supervised Machine Learning to Identify Patients at Risk for Venous Thromboembolism Following Posterior Lumbar Fusion.

STUDY DESIGN: Retrospective review. OBJECTIVE: To use predictive modeling and machine learning to identify patients at risk for venous thromboembolism (VTE) following posterior lumbar fusion (PLF) for degenerative spinal pathology. METHODS: Patients undergoing single-level PLF in the inpatient setting were identified in the National Surgical Quality Improvement Program database. Our outcome measure of VTE included all patients who experienced a pulmonary embolism and/or deep venous thrombosis within 30-days of surgery. Two different methodologies were used to identify VTE risk: 1) a novel predictive model derived from multivariable logistic regression of significant risk factors, and 2) a tree-based extreme gradient boosting (XGBoost) algorithm using preoperative variables. The methods were compared against legacy risk-stratification measures: ASA and Charlson Comorbidity Index (CCI) using area-under-the-curve (AUC) statistic. RESULTS: 13, 500 patients who underwent single-level PLF met the study criteria. Of these, 0.95% had a VTE within 30-days of surgery. The 5 clinical variables found to be significant in the multivariable predictive model were: age > 65, obesity grade II or above, coronary artery disease, functional status, and prolonged operative time. The predictive model exhibited an AUC of 0.716, which was significantly higher than the AUCs of ASA and CCI (all, P < 0.001), and comparable to that of the XGBoost algorithm (P > 0.05). CONCLUSION: Predictive analytics and machine learning can be leveraged to aid in identification of patients at risk of VTE following PLF. Surgeons and perioperative teams may find these tools useful to augment clinical decision making risk stratification tool.

Presence and Severity of Mental Illness Is Associated With Increased Risk of Postoperative Emergency Visits, Readmission, and Reoperation Following Outpatient ACDF: A National Database Analysis.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The purpose was to compare rates of postoperative ED visits, readmission, and reoperation between patients with and without preexisting mental illness undergoing outpatient anterior cervical discectomy and fusion (ACDF). METHODS: A retrospective review of the Mariner Database was conducted on patients who underwent ACDF between 2010 and 2017. Exclusion criteria included same day revision surgery and patients with a history of spine infection, trauma, or neoplasm. Patients were grouped into 3 categories: those with existing history of anxiety and/or depression, those with severe mental illness, and those without any history of mental illness. Severe mental illness was defined as a combination of diagnosis including schizophrenia, bipolar disorder, and/or psychotic disorder. Outcome measures were analyzed by comparing groups using multivariate logistic regression. Significance was set at P < 0.05. RESULTS: Patients with anxiety/depression and patients with severe mental illness both had significantly increased risk of ED visits and readmission at 30-day and 90-day intervals. Compared to patients without mental illness, patients with severe mental illness (OR 1.93, P < 0.001) had significantly increased rates of reoperation at 90-days and 1-years postoperatively. Patients with anxiety/depression did not have increased rates of reoperation relative to patients without anxiety/depression at any time interval (P > 0.05). CONCLUSION: Anxiety/depression as well as more severe psychiatric disease such as Schizophrenia and Bipolar disorder were significantly associated with increased healthcare utilization following outpatient ACDF. Patients with preexisting mental illness undergoing outpatient ACDF should be carefully evaluated preoperatively and closely followed postoperatively to reduce risk of adverse events.

Variation in Commercial Insurance Type Impacts Access to Cervical Spine Surgery.

INTRODUCTION: Prior literature has demonstrated that disparities exist in health care access and outcomes by insurance status, and patients with commercial plans fare better than those with Medicaid. However, variation may exist within commercial plans, which may impact care access. The purpose of our study was to determine the association between commercial health insurance plan type and access/time to surgery among patients with degenerative cervical conditions. METHODS: The MarketScan database (IBM Watson Health, Ann Arbor, MI) was utilized to identify the first instance of International Classification of Diseases-10-CM diagnosis codes for cervical myelopathy and radiculopathy. Patients 65 years old or below enrolled from 2015 to 2020 with a minimum of two years of continuous enrollment were included. Surgery for myelopathy included anterior cervical discectomy and fusion (ACDF), posterior cervical laminectomy and fusion, and laminoplasty, whereas surgery for radiculopathy included ACDF, cervical disk arthroplasty, and foraminotomy. The time between first diagnosis and surgery was determined. Insurance plan type was categorized as noncapitated (NC), non-high-deductible health plan, Health Management Organization-type partially or fully capitated plans, or high-deductible health plans (HDHP). Proportional hazards regression was utilized to compare time-to-incidence of surgery by plan type, adjusting for age, and sex. RESULTS: In total, 55,954 patients with cervical myelopathy and 705,117 patients with cervical radiculopathy were included. Mean follow-up was 537 and 657 days for myelopathy and radiculopathy, respectively. At two years postdiagnosis, 22.6% of myelopathy and 5.6% of radiculopathy patients were managed surgically. ACDF was the most common surgery for both myelopathy (85.7% of surgically managed patients) and radiculopathy (80.6%). The mean time to surgery for myelopathy was 101 days, and 196 days for radiculopathy. The most common plan type was NC for both myelopathy (81.5%, n=44,832) and radiculopathy (80.6%, n=559,109). Time-to-occurrence of surgery was significantly higher among both myelopathy and radiculopathy patients with capitated plans and HDHP versus NC plans, but the impact was significantly greater among those with radiculopathy than myelopathy (all P <0.05). CONCLUSIONS: Insurance plan structure has a significant impact on incidence of and on time-to-occurrence of surgery for patients with cervical degenerative conditions. Patients with HDHP plans may experience higher costs, potentially limiting access to care.