Reliability and application of the new morphological classification system for chronic symptomatic osteoporotic thoracolumbar fracture

A Novel Bipedicular Dissociation Fracture Pattern of Vertebral Osteoporotic Fractures of the Elderly

INTRODUCTION

CVFs are common, with several classification systems available. We have encountered osteoporotic vertebral fractures (OVFs) with PDF, a never-described fracture pattern.This study evaluates this unique fracture's characteristics.

METHODS

Retrospective study of surgically treated OVFs during 2016 to 2020.

RESULTS

Of 105 patients, 85 had classifiable OVFs and 20 had uni-PDF (n = 10, 9.5%) or bi-PDF (n = 10, 9.5%). Both cohorts mainly had single vertebral fractures and upper end plate involvement with cleft sign found in 30% of PDFs versus 15.3% of OVFs (P < 0.001), higher incidence of burst fractures (40% vs. 25.9%; P < 0.001). Posterior vertebral body collapse was higher for PDFs (13.2 ± 9.3% vs. 18.3 ± 8.5%; P = 0.02). Most OVFs underwent balloon kyphoplasty (BKP) (94%). Most bi-PDFs were regarded unstable; six patients underwent PSF (2 short PSF, 1 PSF + BKP, and 3 BKP with intravertebral pedicular lag screws at the fractured vertebra). Half of the bi-PDFs underwent BKP-developed nonunion.

CONCLUSION

Our study is novel in describing an unrecognized OVF pattern disregarded in current classification systems. We found notable differences in fracture characteristics, prefracture functional status, and surgical results between OVF and PDF cohorts. We suggest adding this fracture pattern as a unique OF-4 subtype or a specific entity between OF-4 and 5, with uni-PDF as type A and bi-PDF as type B.

Exploring deep learning radiomics for classifying osteoporotic vertebral fractures in X-ray images

Purpose

To develop and validate a deep learning radiomics (DLR) model that uses X-ray images to predict the classification of osteoporotic vertebral fractures (OVFs).

Material and methods

The study encompassed a cohort of 942 patients, involving examinations of 1076 vertebrae through X-ray, CT, and MRI across three distinct hospitals. The OVFs were categorized as class 0, 1, or 2 based on the Assessment System of Thoracolumbar Osteoporotic Fracture. The dataset was divided randomly into four distinct subsets: a training set comprising 712 samples, an internal validation set with 178 samples, an external validation set containing 111 samples, and a prospective validation set consisting of 75 samples. The ResNet-50 architectural model was used to implement deep transfer learning (DTL), undergoing -pre-training separately on the RadImageNet and ImageNet datasets. Features from DTL and radiomics were extracted and integrated using X-ray images. The optimal fusion feature model was identified through least absolute shrinkage and selection operator logistic regression. Evaluation of the predictive capabilities for OVFs classification involved eight machine learning models, assessed through receiver operating characteristic curves employing the "One-vs-Rest" strategy. The Delong test was applied to compare the predictive performance of the superior RadImageNet model against the ImageNet model.

Results

Following pre-training separately on RadImageNet and ImageNet datasets, feature selection and fusion yielded 17 and 12 fusion features, respectively. Logistic regression emerged as the optimal machine learning algorithm for both DLR models. Across the training set, internal validation set, external validation set, and prospective validation set, the macro-average Area Under the Curve (AUC) based on the RadImageNet dataset surpassed those based on the ImageNet dataset, with statistically significant differences observed (P<0.05). Utilizing the binary "One-vs-Rest" strategy, the model based on the RadImageNet dataset demonstrated superior efficacy in predicting Class 0, achieving an AUC of 0.969 and accuracy of 0.863. Predicting Class 1 yielded an AUC of 0.945 and accuracy of 0.875, while for Class 2, the AUC and accuracy were 0.809 and 0.692, respectively.

Conclusion

The DLR model, based on the RadImageNet dataset, outperformed the ImageNet model in predicting the classification of OVFs, with generalizability confirmed in the prospective validation set.

EXPANDABLE INTRAVERTEBRAL IMPLANTS IN POST-TRAUMATIC VERTEBRAL NECROSIS - NEW CLASSIFICATION SUGGESTION

The progressive evolution of post-traumatic vertebral necrosis and consequent loss of structural integrity of the vertebral body along with neurological risk, makes it one of the most feared and unpredictable pathologies in spine traumatology. Several studies have addressed the role of vertebroplasty, kyphoplasty, and corpectomy in its treatment; however, it remains a controversial concept without a defined therapeutic algorithm. The recent emergence of expandable intravertebral implants, which allow, by a percutaneous transpedicular application, the capacity for intrasomatic filling and maintenance of the height of the vertebral body, makes them a viable option, not only in the treatment of acute vertebral fractures, but also in non-union cases. In this study, we present a review of the current evidence on the application of expandable intravertebral implants in cases of post-traumatic vertebral necrosis. Based on the available scientific literature, including previous classifications of post-traumatic necrosis, and on the mechanical characteristics of the main expandable intravertebral implants currently available, we propose a simplified classification of this pathology, considering parameters that influence surgical therapeutic guidance, the morphology and the dynamics of the necrotic vertebra's mobility. According to its stages and based on authors' experience and on the scarce literature, we propose an initial therapeutic algorithm and suggest preventive strategies for this disease, considering its main risk factors, that is, fracture comminution and impairment of vertebral vascularity. Therefore, expandable intravertebral implants have a promising role in this condition; however, large prospective studies are needed to confirm their efficacy, to clarify the indications of each of these devices, and to validate the algorithm suggestion regarding treatment and prevention of post-traumatic vertebral necrosis. Level of Evidence III, Systematic Review/Actualization.

Grading Systems of Lumbar Facet Joint Inflammatory Changes on Magnetic Resonance Imaging: A Scoping Review

STUDY DESIGN

A scoping review.

OBJECTIVE

We aimed to identify and characterize grading systems of the inflammatory features of the lumbar facet joints (FJs) noted on magnetic resonance imaging and summarize their reliability.

SUMMARY OF BACKGROUND DATA

Chronic low back pain is one of the most common causes of disability worldwide and is frequently accompanied by FJ osteoarthritis. Inflammatory changes in the lumbar FJs are commonly noted in imaging studies of patients with FJ osteoarthritis and low back pain. Several grading systems for these inflammatory changes have been developed. However, these grading system's features and reliability have yet to be reviewed.

MATERIALS AND METHODS

We performed a literature search of studies reporting grading systems for FJ inflammatory changes published in English or Spanish between 1985 and 2022. We collected data on reported interreader reliability measures of each grading system. Finally, we compared the features of inflammation described by each system.

RESULTS

Six studies met the inclusion criteria and were used in our analysis. Features commonly graded in these systems are the hyperintensity signal noted within the FJ, bone marrow edema, and the extent of the soft-tissue edema surrounding the FJs. We found that the interreader reliability measures ranged from 0.56 to 0.96.

CONCLUSIONS

Only 6 studies have reported methods for documenting inflammation in the FJs. Studies varied in the precise tissues and phenomena included in the grading systems. However, the systems were generally reliable. Future studies should document the reliability of these methods when independent investigators are not involved in developing the classification schemes. Further work might combine one or more of these measures to establish a standard and reliable grading system for inflammatory changes in the FJs, including signal intensity within the joint, bone marrow edema, and soft-tissue inflammation.

Internal replacement of a vertebral body in pseudarthrosis-Armed kyphoplasty with bone graft-filled stents: Case report

Background

Post-traumatic vertebral necrosis and pseudarthrosis represents one of the most concerning and unpredictable challenges in spinal traumatology. The evolution of this disease at the thoracolumbar transition usually courses with progressive bone resorption and necrosis, leading to vertebral collapse, retropulsion of the posterior wall and neurological injury. As such, the therapeutic goal is the interruption of this cascade, seeking to stabilize the vertebral body and avoid the negative consequences of its collapse.

Case description

We present a clinical case of a pseudarthrosis of T12 vertebral body with severe posterior wall collapse, treated with removal of intravertebral pseudarthrosis focus by transpedicular access, T12 armed kyphoplasty with VBS® stents filled with cancellous bone autograft, laminectomy and stabilization with T10-T11-L1-L2 pedicle screws. We present clinical and imaging detailed results at 2-year follow-up and discuss our option for this biological minimally invasive treatment for vertebral pseudarthrosis that mimics the general principles of atrophic pseudarthrosis therapeutic and allows to perform an internal replacement of the necrotic vertebral body, avoiding the aggression of a total corpectomy.

Conclusions

This clinical case demonstrates a successful outcome of the surgical treatment of pseudarthrosis of vertebral body (mobile nonunion vertebral body) in which expandable intravertebral stents allow to perform an internal replacement of the necrotic vertebral body by creating intrasomatic cavities and filling them with bone graft, obtaining a totally bony vertebra with a metallic endoskeleton, which is biomechanically and physiologically more similar to the original one. This biological internal replacement of the necrotic vertebral body technique can be a safe and effective alternative over cementoplasty procedures or total vertebral body corpectomy and replacement for vertebral pseudarthrosis and may have several advantages over them, however long-term prospective studies are needed in order to prove the effectiveness and advantages of this surgical option in this rare and difficult pathological entity.

Risk factors for proximal junctional kyphosis after posterior long-segment internal fixation for chronic symptomatic osteoporotic thoracolumbar fractures with kyphosis

Background

This study aimed to analyze the risk factors for proximal junctional kyphosis (PJK) for patients with chronic symptomatic osteoporotic thoracolumbar fractures (CSOTLF) and kyphosis who underwent long-segment internal fixation.

Methods

We retrospectively reviewed the records of patients with CSOTLF complicated with kyphosis who underwent posterior multilevel internal fixation in our hospital between January 2013 and January 2020. The patients’ age, sex, body mass index (BMI), bone mineral density (BMD), smoking status, cause of injury, comorbidities, injury segments, and American Spinal Injury Association (ASIA) grading non-surgical data; posterior ligament complex (PLC) injury, upper and lower instrumented vertebral position (UIV and LIV, respectively), number of fixed segments surgical data, proximal junctional angle (PJA), sagittal vertebral axis (SVA), pelvic incidence (PI), lumbar lordosis (LL), pelvic incidence-lumbar lordosis mismatch (PI-LL), pelvic tilt (PT), and sacral slope (SS) surgical indicators were collected. Patients were divided into postoperative PJK and non-PJK groups.

Results

This study included 90 patients; among them, 30 (31.58%) developed PJK postoperatively. All patients were followed up for > 24 months (mean 32.5 months). Univariate analysis showed significant differences in age, BMI, BMD, PLC injury, UIV, and LIV fixation position, number of fixation stages, and preoperative PJA, SVA, PI-LL, and SS between the two groups (P < 0.05). Additionally, no significant differences were observed in sex, smoking, cause of injury, complications, injury segment ASIA grade, and preoperative PT between the two groups (P > 0.05). Multifactorial logistic regression analysis showed that age > 70 years (OR = 32.279, P < 0.05), BMI > 28 kg/m² (OR = 7.876, P < 0.05), BMD T value < − 3.5 SD (OR = 20.836, P < 0.05), PLC injury (OR = 13.981, P < 0.05), and preoperative PI-LL > 20° (OR = 13.301, P < 0.05) were risk factors for PJK after posterior long-segment internal fixation in elderly patients with CSOTLF complicated with kyphosis.

Conclusion

CSOTLF patients undergoing posterior long segment internal fixation are prone to PJK, and age > 70 years, BMI > 28 kg/m2, BMD T value < − 3.5 SD, preoperative PI-LL > 20° and PLC injury may increase their risk.

Reliability Evaluation of the New AO Spine-DGOU Classification for Osteoporotic Thoracolumbar Fractures

OBJECTIVES

To perform an interobserver and intraobserver agreement evaluation of the new AO Spine-DGOU classification system for osteoporotic thoracolumbar fractures (OFc).

METHODS

Complete imaging studies of 97 patients (radiographs, computed tomography scans, and magnetic resonance imaging) with osteoporotic thoracolumbar fractures were selected and classified using the OFc by 6 spine surgeons (3 senior surgeons with more than 15 years of experience and 3 surgeons with less than 15 years). After a 4-week interval, the same cases were presented to the same evaluators in a random sequence for a new classification assessment. The weighted kappa coefficient (wκ) was used to determine the interobserver and intraobserver agreement.

RESULTS

The interobserver agreement was moderate, wκ = 0.59 (95% confidence interval 0.54-0.64). The intraobserver agreement was fair, wκ = 0.35 (95% confidence interval 0.29-0.40). Interobserver agreement slightly improved for junior staff between first and second evaluation, suggesting a learning effect. Better agreement was obtained by senior staff at the interobserver and intraobserver agreement.

CONCLUSIONS

This independent assessment demonstrated that new OFc allows moderate interobserver agreement and fair intraobserver agreement. Further studies are necessary prior to its widespread adoption.

Inter- and intraobserver reliabilities and critical analysis of the osteoporotic fracture classification of osteoporotic vertebral body fractures

PURPOSE

The Osteoporotic Fracture Working Group (Spine Division of the German Orthopaedic and Trauma Society) has developed a classification system for osteoporotic thoracolumbar fractures, namely the osteoporotic fracture (OF) classification system. The purpose of this study was to determine the inter- and intraobserver reliabilities of the OF classification system for osteoporotic vertebral body fractures (VFs) at a level-one trauma centre.

METHODS

Conventional radiography, magnetic resonance imaging (MRI), and computed tomography (CT) scans of 54 consecutive women who sustained an osteoporotic VF were analysed by six orthopaedic traumatologists with varying levels of experience. The inter- and intraobserver reliabilities of the OF classification system were determined using intraclass correlation coefficients (ICCs) and Cohen's kappa.

RESULTS

The overall interobserver reliability of the OF classification system was good (ICC, 0.62 [0.51, 0.72]). The intraobserver reliability was found to be substantial (overall weighted Cohen's kappa estimate [95% confidence interval {CI}] = 0.74 [0.67, 0.80]) and better when the radiography, MRI, and CT scans were assessed together than when only the radiography and MRI scans were evaluated, although the difference was not significant.

CONCLUSION

The OF classification system is easy to use. It shows good interobserver reliability and substantial intraobserver reliability if diagnostic prerequisites (conventional radiography, MRI, and CT scans) are met.

Spinous Process Fractures in Osteoporotic Vertebral Fractures: A Cross-Sectional Study

Introduction

The purpose of this study was to assess radiological features and clinical scores of osteoporotic vertebral fracture (OVF) accompanied by spinous process fracture (SPF).

Methods

We included painful patients with single-level OVF with intravertebral cleft. SPF was detected using magnetic resonance imaging (MRI) and/or computed tomography (CT). The plain radiographs of the vertebral fractures were evaluated based on the wedging angle of the fractured vertebrae and vertebral instability. We investigated the clinical parameters of age, gender, visual analog scale (VAS) score for low back pain (LBP), Oswestry Disability Index (ODI), and the period from the onset of acute fracture.

Results

MRI and/or CT indicated among 195 patients of OVF with LBP, 41 patients (20.5%) had SPFs. SPFs were observed one level above the fractured vertebral body in 35 patients (85.4%) and at the same level as the fractured vertebral body in 6 patients (14.6%). The prevalence of vertebral fracture of thoracic spine in the SPF-positive group was significantly greater than that in the SPF-negative group. There were no significant differences in age, gender, VAS, ODI, the time period from the onset of acute LBP, wedging angle, and vertebral instability between the presence or absence of SPFs.

Conclusions

SPFs occurred in 20.5% of patients with OVF and LBP. In addition, SPFs often occurred one level above the fractured vertebra, and SPFs with OVF tended to be located in the thoracic spine.

A predictive scoring system for proximal junctional kyphosis after posterior internal fixation in elderly patients with chronic osteoporotic vertebral fracture: A single-center diagnostic study

OBJECTIVE

To establish a predictive scoring system for proximal junctional kyphosis (PJK) after posterior internal fixation in elderly patients with chronic osteoporotic vertebral fracture (COVF).

MATERIALS AND METHODS

The medical records of 88 patients who were diagnosed with COVF and underwent posterior internal fixation in our hospital from January 2013 to December 2017 were retrospectively analyzed. The included patients were divided into two groups according to whether they suffered PJK after surgery, namely, the PJK group (25 cases) and non-PJK group (63 cases). The following clinical characteristics were recorded and analyzed: age, gender, body mass index (BMI), bone mineral density (BMD), smoking history, fracture segment, proximal junction angle, sagittal vertebral axis, pelvic incidence (PI)-lumbar lordosis (LL), pelvic tilt (PT), sacral slope (SS), posterior ligamentous complex (PLC) injury, upper instrumented vertebra, lower instrumented vertebra, and the number of fixed segments. The prevalence of these clinical characteristics in the PJK group was evaluated, and the scoring system was established using logistic regression analysis. The performance of the scoring system was also prospectively validated.

RESULTS

The predictive scoring system was established based on five clinical characteristics confirmed as significant predictors of PJK, namely, age > 70 years, BMI > 28 kg/m², BMD < -3.5 SD, preoperative PI-LL > 20°, and PLC injury. PJK showed a significantly higher score than non-PJK (7.80 points vs. 2.83 points, t=9.556, P<0.001), and the optimal cutoff value for the scoring system was 5 points. The sensitivity and specificity of the scoring system for predicting postoperative PJK were 80.00% and 88.89%, respectively, in the derivation set and 75.00% and 80.00% in the validation set.

CONCLUSION

The predictive scoring system was confirmed with satisfactory sensitivity and specificity in predicting PJK after posterior internal fixation in elderly COVF patients. The risk of postoperative PJK in patients with a score of 6-11 is high, while the score of 0-5 is low.