Prediction of primary admission total charges following cervical disc arthroplasty utilizing machine learning.

BACKGROUND CONTEXT: Cervical disc arthroplasty (CDA) has become an increasingly popular alternative to anterior cervical discectomy and fusion, offering benefits such as motion preservation and reduced risk of adjacent segment disease. Despite its advantages, understanding the economic implications associated with varying patient and hospital factors remains critical. PURPOSE: To evaluate how hospital size, geographic region, and patient-specific variables influence charges associated with the primary admission period following CDA. STUDY DESIGN: A retrospective analysis using machine learning models to predict and analyze charge factors associated with CDA. PATIENT SAMPLE: Data from the National Inpatient Sample (NIS) database from 2016 to 2020 was used, focusing on patients undergoing CDA. OUTCOME MEASURES: The primary outcome was total charge associated with the primary admission for CDA, analyzed against patient demographics, hospital characteristics, and regional economic conditions. METHODS: Multivariate linear regression and machine learning algorithms including logistic regression, random forest, and gradient boosting trees were employed to assess their predictive power on charge outcomes. Statistical significance was set at the 0.003 level after applying a Bonferroni correction. RESULTS: The analysis included 3,772 eligible CDA cases. Major predictors of charge identified were hospital size and ownership type, with large and privately owned hospitals associated with higher charges (p<.001). The Western region of the U.S. also showed significantly higher charges compared to the Northeast (p<.001). The gradient boosting trees model showed the highest accuracy (AUC=85.6%). Length of stay and wage index were significant charge drivers, with each additional inpatient day increasing charges significantly (p<.001) and higher wage index regions correlating with increased charges (p<.001). CONCLUSIONS: Hospital size, geographic region, and specific patient demographics significantly influence the charges of CDA. Machine learning models proved effective in predicting these charges, suggesting that they could be instrumental in guiding economic decision-making in spine surgery. Future efforts should aim to incorporate these models into broader clinical practice to optimize healthcare spending and enhance patient care outcomes.

What Is the Epidemiology of Cervical and Thoracic Spine Fractures?

BACKGROUND: Vertebral fractures are associated with enduring back pain, diminished quality of life, as well as increased morbidity and mortality. Existing epidemiological data for cervical and thoracic vertebral fractures are limited by insufficiently powered studies and a failure to evaluate the mechanism of injury. QUESTION/PURPOSE: What are the temporal trends in incidence, patient characteristics, and injury mechanisms of cervical and thoracic vertebral fractures in the United States from 2003 to 2021? METHODS: The United States National Electronic Injury Surveillance System-All Injury Program (NEISS-AIP) database collects data on all nonfatal injuries treated in US hospital emergency departments and is well suited to capture epidemiological trends in vertebral fractures. As such, the NEISS-AIP was queried from 2003 to 2021 for cervical and thoracic fractures. The initial search by upper trunk fractures yielded 156,669 injuries; 6% (9900) of injuries, with a weighted frequency of 638,999 patients, met the inclusion criteria. The mean age was 62 ± 25 years and 52% (334,746 of 638,999) of patients were females. Descriptive statistics were obtained. Segmented regression analysis, accounting for the year before or after 2019 when the NEISS sampling methodology was changed, was performed to assess yearly injury trends. Multivariable logistic regression models with age and sex as covariates were performed to predict injury location, mechanism, and disposition. RESULTS: The incidence of cervical and thoracic fractures increased from 2.0 (95% CI 1.4 to 2.7) and 3.6 (95% CI 2.4 to 4.7) per 10,000 person-years in 2003 to 14.5 (95% CI 10.9 to 18.2) and 19.9 (95% CI 14.5 to 25.3) in 2021, respectively. Incidence rates of cervical and thoracic fractures increased for all age groups from 2003 to 2021, with peak incidence and the highest rate of change in individuals 80 years or older. Most injuries occurred at home (median 69%), which were more likely to impact older individuals (median [range] age 75 [2 to 106] years) and females (median 61% of home injuries); injuries at recreation/sports facilities impacted younger individuals (median 32 [3 to 96] years) and male patients (median 76% of sports facility injuries). Falls were the most common injury mechanism across all years, with females more likely to be impacted than males. The proportion of admissions increased from 33% in 2003 to 50% in 2021, while the proportion of treated and released patients decreased from 53% to 35% in the same period. CONCLUSION: This epidemiological study identified a disproportionate increase in cervical and thoracic fracture incidence rates in patients older than 50 years from 2003 to 2021. Furthermore, high hospital admission rates were also noted resulting from these fractures. These findings indicate that current osteoporosis screening guidelines may be insufficient to capture the true population at risk of osteoporotic fractures, and they highlight the need to initiate screening at an earlier age. LEVEL OF EVIDENCE: Level III, prognostic study.

Assessment of Cervical and Lumbar Kinematics in Simulated Open and Closed Kinetic Chain.

BACKGROUND: The pelvic girdle and spine vertebral column work as a long chain influenced by pelvic tilt. This study aims to assess the effect of open and closed chain anterior pelvic tilt (APT) or posterior pelvic tilt (PPT) on cervical and lumbar spine kinematics using an in vitro cadaveric spine model. METHODS: Three human cadaveric spines with intact pelvis were suspended with the skull fixed in a metal frame. Optotrak 3-dimensional motion system captured coordinates of pin markers at 24 different points for real-time tracking of cervical and lumbar regions. Additional geometric parameters were measured to calculate pelvic incidence and pelvic tilt. A force-torque digital gauge applied consistent force to standardize the acetabular or sacral axis' APT and PPT during simulated open- and closed-chain movements, respectively. RESULTS: In closed-chain PPT, significant differences in relative intervertebral decompression were noted between spinal levels C2/C3 (4.85 mm) and C5/C6 (1.26 mm), while compression was noted between L1/L2 (-2.54 mm) and L5/S1 (-11.84 mm) and between L3/L4 (-2.78 mm) and L5/S1 (-11.84 mm) (P < 0.05). Displacement during closed-chain PPT was significantly greater than during open-chain PPT for cervical and lumbar spines. In closed-chain APT, significant differences in relative intervertebral decompression were noted between spinal levels L1/L2 (2.87 mm) and L5/S1 (24.48 mm) and between L3/L4 (2.94 mm) and L5/S1 (24.48 mm) (P < 0.05). Pelvic incidence remained the same as the pelvis tilted anterior and posterior. CONCLUSIONS: In PPT, open-chain pelvic tilts did not produce as much cervical and lumbar intervertebral displacement compared with closed-chain pelvic tilts. In contrast, APT saw fewer differences between open- and closed-chain tilting. There was a reciprocal relationship between pelvic tilt and sacral slope, producing a constant pelvic incidence throughout all pelvic tilt angles. CLINICAL RELEVANCE: The results of this study may help determine how a patient's pelvic tilt is causing pain and using that knowledge to guide rehabilitation of stabilizing muscles. The data produced here may also be helpful in determining which rehabilitation exercises may be more difficult or prone to injury for patients with either excessive anterior or posterior pelvic tilt.

Does Preoperative Bone Mineral Density Impact Fusion Success in Anterior Cervical Spine Surgery? A Prospective Cohort Study.

OBJECTIVE: The purpose of this study was to identify risk factors for pseudarthrosis in patients undergoing anterior cervical discectomy and fusion (ACDF) with a focus on the role of bone mineral density (BMD) on arthrodesis. METHODS: We retrospectively reviewed a prospectively collected database of patients undergoing 1- to 4-level ACDF for degenerative indications between 2012 and 2018 at a single institution. All patients were required to have undergone a preoperative dual-energy x-ray absorptiometry (DEXA) scan. Fusion status was assessed on computed tomography (CT) scans obtained 1 year postoperatively. Patients were divided into subgroups based on fusion status and compared on the basis of demographic, BMD, and surgical variables to determine risk factors for pseudarthrosis. RESULTS: We identified 79 patients for inclusion in this study. Fusion was achieved in 65 patients (82%), while 14 patients (18%) developed pseudarthrosis. The pseudarthrosis subgroup demonstrated significantly lower BMD than their counterparts who achieved successful fusion in both mean hip (-1.4 ± 1.2 vs. -0.2 ± 1.2, respectively; P = 0.002) and spine T-scores (-0.8 ± 1.8 vs. 0.6 ± 1.9, respectively; P = 0.02). The pseudarthrosis group had a substantially higher proportion of patients with osteopenia (57.1% vs. 20.0%) and osteoporosis (21.5% vs. 6.2%; P < 0.001) than the fusion group. Multivariate analysis demonstrated osteopenia (odds ratio [OR] 8.76, P = 0.04), osteoporosis (OR 9.97, P = 0.03), and low BMD (OR 11.01, P = 0.002) to be associated with an increased likelihood of developing pseudarthrosis. CONCLUSIONS: The results of this study suggest that both osteopenia and osteoporosis are associated with increased rates of pseudarthrosis in patients undergoing elective ACDF.

Influence of lower limbs discrepancy and pelvic coronal rotation on pelvic incidence, pelvic tilt and sacral slope.

PURPOSE: Pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS) are important parameters in sagittal spine alignment evaluation. The measurements are a projection of the three-dimensional pelvis onto a two-dimensional radiograph and they may be influenced by orientation of the pelvis. The aim of this study was to assess the influence of pelvic rotation in the coronal plane (CPR) on radiographic accuracy of PI, PT, and SS measurements. METHODS: Radiological evaluation of the CPR angel was performed on 1 radiological phantom. The radiographs were taken in 5° CPR increments over a range of 0°-45° (evaluated with a digital protractor). On each of the lateral radiograph, PI, PT, and SS were measured three times by three independent researchers. The lowest CPR that changed PI, PT, or SS by ≥6° (the highest reported error of measurement of these parameters) was considered as unacceptable. Next, CPR was calculated based on the distance between femoral heads (FHD). The agreement of the calculated and measured CPR was quantified by the intraclass correlation coefficient (ICC) and the median error for a single measurement (SEM), with value 0.75 considered as excellent agreement. RESULTS: PI, PT and SS could be measured with an acceptable error of 6° on radiographs with up to 20° pelvic rotation. From 20° CPR onwards the S1 endplate was distorted, that makes the measurements of PI, PT and SS questionable. There was an excellent agreement between CPR measured with a protractor and calculated based on FHD with ICC of 0.99 and SEM of 1.1°. CONCLUSIONS: Rotation of the pelvis in the coronal plane during acquisition of radiographs influences PI, PT and SS measurements. Substantial error of PI, PT and SS measurements occurs with CPR of more than 20° which is equivalent to a lower limb discrepancy of 5.2 cm. CPR may be calculated while acquiring the radiograph. Further evaluation of the influence of CPR on spinopelvic parameters with a larger sample would be valuable.

Varus knee osteoarthritis: how can we identify ACL insufficiency?

PURPOSE: The aim of this prospective study was to determine the clinical value of lateral radiographs and corresponding MRI scans in the preoperative evaluation of the functional integrity of the anterior cruciate ligament (ACL) in a consecutive series of 78 patients (93 knees) with medial compartment osteoarthritis. METHODS: All knees received standardised radiographs and MRI imagery. The wear pattern on the lateral radiograph was described based on a modified Keyes classification. On MRI, the ACL and the percentage of intact posterior cartilage in relation to the anteroposterior tibia width were assessed. RESULTS: The MRI showed an intact ACL in 23 (25 %) knees, evidence of ACL degeneration in 54 (58 %) knees and a complete ACL tear in 16 (17 %) knees. All knees with an intact ACL showed ≥14 % intact posterior cartilage on sagittal MRI scans, except for one knee. All knees with a torn ACL demonstrated <14 % intact posterior cartilage. Of the 54 knees with evidence of ACL degeneration, eight knees had <14 % intact posterior cartilage similar to the wear pattern present in knees with torn ACLs. Out of the 24 knees with a torn or degenerated ACL and <14 % intact posterior cartilage on MRI, 23 (96 %) knees demonstrated posterior bony erosion on corresponding lateral radiographs. CONCLUSIONS: The assessment of intact posterior tibial cartilage on MRI and lateral radiographs helps to identify knees with functional ACL insufficiency. MRI with assessment of both the ACL morphology and the underlying tibial wear pattern appears to provide additional clinical benefit in cases in which the extent of posterior bony erosion on the lateral radiograph cannot be assessed with confidence. LEVEL OF EVIDENCE: Diagnostic study, Level II.