Predictors of kyphotic deformity in osteoporotic vertebral compression fractures: a radiological study

Does Early Treatment With Teriparatide Prevent the Need for Surgical Intervention in Osteoporotic Vertebral Compression Fractures

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVE

The primary objective of this study is to evaluate the efficacy of early administration of Teriparatide in preventing the necessity of surgical intervention in individuals with osteoporotic vertebral compression fractures.

METHODS

In a 24-month follow-up retrospective analysis, 191 OVCF patients from January 2016 to October 2020 were randomly assigned to Non teriparatide Group A (n = 104) or Group B teriparatide (n = 87). At baseline, 6 months, 1 year, and 2 years following treatment, demographic data and need of surgical intervention, VAS, ODI, union rates, and kyphosis development, were examined.

RESULTS

Our study found that non-teriparatide group individuals had an 11.53% higher risk of non-union formation that required surgery. Only 8.63% of teriparatide group patients needed surgery. Both groups had significant VAS score reductions. Non-teriparatide group scores declined from 8.38 ± 0.74 to 3.15 ± 1.40, while teriparatide group scores decreased from 8.49 ± 0.73 to 1.11 ± 0.31. The 2-year follow-up ODI scores significantly decreased, with values of 25.02 ± 13.94 for non-teriparatide patients and 15.11 ± 2.17 for teriparatide patients. The kyphosis progression angles in the teriparatide group were considerably lower (4.97 ± 0.78°) compared to the other group (8.09 ± 1.25°).

CONCLUSION

With increasing elderly populations, it is necessary to take measures to prevent surgical intervention in osteoporotic spinal compression fractures. Teriparatide can be employed as an early medication in the management of these fractures to avert non-union and the minimise the progression of kyphosis.

Multidisciplinary and Coordinated Management of Osteoporotic Vertebral Compression Fractures: Current State of the Art

Osteoporotic vertebral compression fractures (OVCFs) present a significant health concern, affecting a substantial portion of the older adult population worldwide. This narrative review explores the prevalence, diagnostic challenges and management strategies for OVCFs. Despite the increasing incidence and impact on morbidity and mortality, existing clinical guidelines lack consistency and clear diagnostic and therapeutic recommendations. The review addresses key questions faced by physicians dealing with older adult patients experiencing acute back pain, offering insights into triage, radiological assessments and classification systems. We propose a comprehensive algorithm for clearing OVCF, considering clinical presentation, radiological findings and morphological aspects. Emphasis is placed on the importance of medically treating osteoporosis alongside OVCF management. The review encompasses relevant literature from 1993 to 2023, provides a detailed discussion on triage issues and incorporates a clinically oriented classification system developed by the German Society for Orthopaedics and Trauma. The Material and Methods section outlines the extensive literature search carried out in PUBMED, encompassing clinical and experimental studies, systematic reviews and meta-analyses. The articles retained focused mainly on answering critical questions regarding radiological assessments, imaging modalities and the presence of a specific classification system for OVCFs. The review emphasises that the evaluation and management of OVCFs necessitates a multidisciplinary approach involving spine specialists and bone disease experts. It also addresses the role of conservative versus surgical treatments, with a focus on percutaneous vertebral augmentation. The conclusion summarises the algorithm derived for use in emergency departments and general practice, aiming to streamline OVCF management, reduce unnecessary examinations and ensure optimal patient care. The algorithm recommends primary diagnosis using computed tomography, with magnetic resonance imaging reserved for specific cases. The review advocates a holistic approach, integrating medical and surgical interventions to address the complex challenges posed by OVCFs in ageing populations.

Is Teriparatide Superior in Treating Osteoporotic Vertebral Compression Fractures in Comparison to Bisphosphonates Treatment Alone: A 2-Year Retrospective Analysis

STUDY DESIGN

Retrospective cohort study.

PURPOSE

This study aimed to compare the efficacy of bisphosphonates and teriparatide in the management of osteoporotic vertebral compression fractures with regard to pain management, prevention of nonunion, and radiological as well as clinical outcomes.

OVERVIEW OF LITERATURE

Osteoporosis refers to a skeletal disorder characterized by decreased bone strength caused by poor bone density and quality causing fragility, resulting in long periods of pain-related immobilization.

METHODS

In a 24-month follow-up retrospective study, 191 patients with osteoporotic vertebral compression fractures were randomly assigned to the bisphosphonate group (n=104) or the teriparatide group (n=87), with patients opting for their treatment between January 2016 and October 2020. Demographic data and patient-reported outcomes scores, including the Visual Analog Scale (VAS), Oswestry Disability Index (ODI), union rates, and kyphosis progression, were assessed at baseline, 6 months, 1 year, and 2 years after treatment.

RESULTS

Both groups had a significant decrease in VAS, from 8.38±0.74 to 3.15±1.40 in the bisphosphonate group and from 8.49±0.73 to 1.11±0.31 in the teriparatide group. The ODI scores reduced significantly at 2-year follow-ups, recording 25.02±13.94 and 15.11±2.17 in the bisphosphonate and teriparatide groups, respectively. Risks of nonunion development were slightly higher at 11.53% in the bisphosphonate group and 8.63% in the teriparatide group required operative intervention. The kyphosis progression angles were also significantly lower in the teriparatide group (4.97°±0.78°) than in the bisphosphonate group (8.09°±1.25°).

CONCLUSIONS

Over time, numerous studies have demonstrated the efficacy of bisphosphonates and teriparatide in ameliorating pain. In this study, the efficacy of teriparatide surpassed that of bisphosphonates in certain aspects, such as the initial 6-month union rates and reduction in the progression of segmental kyphosis. However, bisphosphonates and teriparatide yield similar and favorable union rates at 1 year and final follow-up.

Prediction of Progressive Collapse in Osteoporotic Vertebral Fractures Using Conventional Statistics and Machine Learning

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The objective of this study was to determine prognostic factors for the progression of osteoporotic vertebral fracture (OVF) following conservative treatment.

SUMMARY OF BACKGROUND DATA

Few studies have evaluated factors associated with progressive collapse (PC) of OVFs. Furthermore, machine learning has not been applied in this context.

MATERIALS AND METHODS

The study involved the PC and non-PC groups based on a compression rate of 15%. Clinical data, fracture site, OVF shape, Cobb angle, and anterior wedge angle of the fractured vertebra were evaluated. The presence of intravertebral cleft and the type of bone marrow signal change were analyzed using magnetic resonance imaging. Multivariate logistic regression analysis was performed to identify prognostic factors. In machine learning methods, decision tree and random forest models were used.

RESULTS

There were no significant differences in clinical data between the groups. The proportion of fracture shape ( P <0.001) and bone marrow signal change ( P =0.01) were significantly different between the groups. Moderate wedge shape was frequently observed in the non-PC group (31.7%), whereas the normative shape was most common in the PC group (54.7%). The Cobb angle and anterior wedge angle at diagnosis of OVFs were higher in the non-PC group (13.2±10.9, P =0.001; 14.3±6.6, P <0.001) than in the PC group (10.3±11.8, 10.4±5.5). The bone marrow signal change at the superior aspect of the vertebra was more frequently found in the PC group (42.5%) than in the non-PC group (34.9%). Machine learning revealed that vertebral shape at initial diagnosis was a main predictor of progressive vertebral collapse.

CONCLUSION

The initial shape of the vertebra and bone edema pattern on magnetic resonance imaging appear to be useful prognostic factors for progressive collapse in osteoporotic vertebral fractures.

Development and Internal Validation of Supervised Machine Learning Algorithm for Predicting the Risk of Recollapse Following Minimally Invasive Kyphoplasty in Osteoporotic Vertebral Compression Fractures

Background

The published literatures indicate that patients with osteoporotic vertebral compression fractures (OVCFs) benefit significantly from percutaneous kyphoplasty (PKP), but this surgical technique is associated with frequent postoperative recollapse, a complication that severely limits long-term postoperative functional recovery.

Methods

This study retrospectively analyzed single-segment OVCF patients who underwent bilateral PKP at our academic center from January 1, 2017 to September 30, 2019. Comparing the plain films of patients within 3 days after surgery and at the final follow-up, we classified patients with more than 10% loss of sagittal anterior height as the recollapse group. Univariate and multivariate logistic regression analyses were performed to determine the risk factors affecting recollapse after PKP. Based on the logistic regression results, we constructed one support vector machine (SVM) classifier to predict recollapse using machine learning (ML) algorithm. The predictive performance of this prediction model was validated by the receiver operating characteristic (ROC) curve, 10-fold cross validation, and confusion matrix.

Results

Among the 346 consecutive patients (346 vertebral bodies in total), postoperative recollapse was observed in 40 patients (11.56%). The results of the multivariate logistical regression analysis showed that high body mass index (BMI) (Odds ratio [OR]: 2.08, 95% confidence interval [CI]: 1.58–2.72, p < 0.001), low bone mineral density (BMD) T-scores (OR: 4.27, 95% CI: 1.55–11.75, p = 0.005), presence of intravertebral vacuum cleft (IVC) (OR: 3.10, 95% CI: 1.21–7.99, p = 0.019), separated cement masses (OR: 3.10, 95% CI: 1.21–7.99, p = 0.019), cranial endplate or anterior cortical wall violation (OR: 0.17, 95% CI: 0.04–0.79, p = 0.024), cement-contacted upper endplate alone (OR: 4.39, 95% CI: 1.20–16.08, p = 0.025), and thoracolumbar fracture (OR: 6.17, 95% CI: 1.04–36.71, p = 0.045) were identified as independent risk factors for recollapse after a kyphoplasty surgery. Furthermore, the evaluation indices demonstrated a superior predictive performance of the constructed SVM model, including mean area under receiver operating characteristic curve (AUC) of 0.81, maximum AUC of 0.85, accuracy of 0.81, precision of 0.89, and sensitivity of 0.98.

Conclusions

For patients with OVCFs, the risk factors leading to postoperative recollapse were multidimensional. The predictive model we constructed provided insights into treatment strategies targeting secondary recollapse prevention.

Osteoporotic vertebral fractures: radiologic diagnosis, clinical and radiologic factors affecting surgical decision making: WFNS Spine Committee Recommendations

With the varied literature on osteoporotic vertebral fracture that may predispose to diagnostic and management dilemma, it is timely to evaluate and streamline the evidence. The aim of this review is to create recommendations on osteoporotic vertebral fractures regarding radiologic diagnosis, and clinical and radiological factors affecting surgical decision making. A computerized literature search was done using PubMed, Google scholar and Cochrane Database of Systematic Reviews from 2010 to 2020. For radiologic diagnosis, the keywords "osteoporotic vertebral fractures" and "radiologic diagnosis" were used yielding 394 articles (19 relevant articles). For clinical and radiological factors affecting surgical decision making, the keywords "osteoporotic vertebral fractures", "radiologic diagnosis", and "surgery" were used yielding 568 articles (25 relevant articles). All pertinent data were reviewed, and consensus statements were obtained in two virtual separate consensus meetings of the World Federation of Neurosurgical Societies (WFNS) Spine committee. The statements were voted and yielded positive or negative consensus using the Delphi method. This review summarizes the WFNS Spine Committee recommendations on the radiologic diagnosis, and clinical and radiological factors affecting surgical decision making of osteoporotic vertebral fractures.

Risk Factors for Failure in Conservatively Treated Osteoporotic Vertebral Fractures: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVES

Osteoporosis is one of the most common diseases of the elderly, whereby vertebral body fractures are in many cases the first manifestation. Even today, the consequences for patients are underestimated. Therefore, early identification of therapy failures is essential. In this context, the aim of the present systematic review was to evaluate the current literature with respect to clinical and radiographic findings that might predict treatment failure.

METHODS

We conducted a comprehensive, systematic review of the literature according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) checklist and algorithm.

RESULTS

After the literature search, 724 potentially eligible investigations were identified. In total, 24 studies with 3044 participants and a mean follow-up of 11 months (range 6-27.5 months) were included. Patient-specific risk factors were age >73 years, bone mineral density with a t-score <-2.95, BMI >23 and a modified frailty index >2.5. The following radiological and fracture-specific risk factors could be identified: involvement of the posterior wall, initial height loss, midportion type fracture, development of an intravertebral cleft, fracture at the thoracolumbar junction, fracture involvement of both endplates, different morphological types of fractures, and specific MRI findings. Further, a correlation between sagittal spinal imbalance and treatment failure could be demonstrated.

CONCLUSION

In conclusion, this systematic review identified various factors that predict treatment failure in conservatively treated osteoporotic fractures. In these cases, additional treatment options and surgical treatment strategies should be considered in addition to follow-up examinations.

Paraspinal muscle fatty degeneration as a predictor of progressive vertebral collapse in osteoporotic vertebral compression fractures

BACKGROUND CONTEXT

Most osteoporotic vertebral compression fractures (OVCFs) are treated conservatively; however, in some patients, progressive vertebral body collapse leads to spinal deformity and cord compression. These complications are strongly associated with impaired performance activities of daily living and a poor quality of life.

PURPOSE

To identify the role of the paraspinal muscle as a risk factor for progressive vertebral body collapse in patients with OVCF.

STUDY DESIGN

This was a retrospective observational study.

PATIENT SAMPLE

Fifty-five consecutive patients with OVCF who were treated conservatively from January 2018 to June 2020 in a single spine center and had a minimum follow-up of 6 months.

OUTCOME MEASURES

A lateral plain radiograph in a neutral posture was taken when the patient was first diagnosed and at 1, 3, and 6 months after the first diagnosis. Vertebral height was measured at the point of maximal collapse of the affected vertebral body; vertebral collapse (%) was also measured. The cross-sectional area (CSA) and fatty degeneration of the paraspinal muscle were measured using the open-source software Image J. The visual analogue scale (VAS) scores were collected at the time of initial fracture diagnosis and at 1, 3, and 6 months.

METHODS

The clinical and radiological data were analyzed. In the L4-5 intervertebral disc level, axial T2-weighted magnetic resonance imaging was used to measure the CSA and fatty degeneration of the paraspinal muscles. Correlation and multiple regression analyses were performed to analyze the risk factors associated with progressive vertebral body collapse.

RESULTS

The vertebral collapse difference was strongly associated with paraspinal muscle fatty degeneration (r=0.684, p=.000) and body mass index (r=0.300, p=.026). Multiple linear regression analysis demonstrated that the risk factor for progression of vertebral collapse was paraspinal muscle fatty degeneration (β=0.724, p=.000). There was a statistically significant correlation between the progression in vertebral collapse and VAS score at 3 (r=0.402, p=.002) and 6 months (r=0.604, p=.000).

CONCLUSIONS

In patients with OVCF, fatty degeneration of the paraspinal muscle was a predictive factor for progressive vertebral body collapse. This study suggests that more attention should be paid to patients with paraspinal sarcopenia among those with OVCFs.

Relationship between number of radiological risk factors for delayed union after osteoporotic vertebral fracture and clinical outcomes

This study demonstrated that number of three specific radiological risk factors (MR T2WI confined high-intensity pattern and diffuse low-intensity pattern, thoracolumbar vertebrae involvement, middle column injury) added prognostic information for delayed union, kyphotic deformity, and prolonged pain.

PURPOSE

Delayed union after osteoporotic vertebral fracture (OVF) causes prolonged pain, QOL impairment, progression of collapse, kyphotic deformity, and neurologic impairment. Some specific radiological findings can be useful for predicting delayed union. We aimed to explore the prevalence and concomitance of various types of radiological risk factors for delayed union after osteoporotic vertebral fracture (OVF) and to assess the impact of risk factor number on clinical outcomes.

METHODS

A total of 508 patients with fresh OVF from 25 institutes were evaluated. All patients were treated conservatively without surgical interventions. At the 6-month follow-up, the patients were classified into bone union and delayed union groups based on plain X-ray findings. We examined the presence and absence of three specific radiological risk factors (MR T2WI confined high-intensity pattern and diffuse low-intensity pattern, thoracolumbar vertebrae involvement, middle column injury) and analyzed clinical outcomes according to numbers of radiological risk factors.

RESULTS

Delayed union was observed in 101 patients (19.9%) at the 6-month follow-up. The most common radiological risk factor was thoracolumbar vertebrae involvement (73.8%), followed by middle column injury (33.9%) and specific MRI findings (T2WI confined high-intensity pattern and diffuse low-intensity pattern) (29.7%). Overall, 85 (16.7%) patients had zero radiological risk factors, 212 (42.7%) had one, 137 (27.0%) had two, and 69 (13.6%) had three. When assessing the number of radiographic risk factors which included the MRI findings (the 3-risk factor method), the odds ratio for delayed union after acute OVF was 5.8 in the 2/3-risk factor group and 13.1 in the 3/3-risk factor group. Even when assessing the number of radiographic risk factors without MRI findings (2-risk factor method), the odds ratio was 3.2 in the 1/2-risk factor group and 10.2 in the 2/2-risk factor group.

CONCLUSION

Number of radiological risk factors added prognostic information for delayed union, kyphotic deformity, and prolonged pain.

Use of proton density fat fraction MRI to predict the radiographic progression of osteoporotic vertebral compression fracture

OBJECTIVE

This study evaluated the diagnostic performance of the proton density fat fraction (PDFF) in predicting the progression of osteoporotic vertebral compression fractures (OVCFs).

METHODS

The cohort in this retrospective study consisted of 48 patients with OVCFs who underwent spine MRI that included PDFF between December 2016 and June 2018. The patients were divided into two groups (with versus without OVCF progression, based on the radiographic results obtained at the 6-month follow-up examination). Two musculoskeletal radiologists independently calculated the PDFF of the fracture and the PDFF ratio (fracture PDFF/normal vertebrae PDFF) using regions of interest. The mean values of these parameters were compared between the two groups, and the receiver operating characteristic curves were analysed.

RESULTS

The mean age was significantly higher in the group with OVCF progression (71.6 ± 8.4 years) than in the group without (64.8 ± 10.5 years) (p = 0.018). According to reader 1, the PDFF ratio was significantly lower in the group with OVCF progression versus that without OVCF progression (0.38 ± 0.13 vs 0.51 ± 0.20; p = 0.009), whereas the difference in the PDFF itself was not statistically significant. The PDFF ratio [area under the curve (AUC) = 0.723; 95% confidence interval (CI), 0.575-0.842] had a larger AUC than did the PDFF (AUC = 0.667; 95% CI, 0.516-0.796). The optimal cut-off value of the PDFF ratio for predicting OVCF progression was 0.42; this threshold corresponded to sensitivity, specificity, and accuracy values of 84.0%, 60.9%, and 72.9%, respectively.

CONCLUSION

The age and PDFF ratio can be used to predict OVCF progression.

KEY POINTS

• Chemical shift-encoded magnetic resonance imaging provides quantitative parameters for predicting OVCF progression. • The PDFF ratio is significantly lower in patients with OVCF progression. • The PDFF ratio is superior to the PDFF for predicting OVCF progression.

Changes in magnetic resonance imaging signal intensity in predicting complications during acute phase osteoporotic vertebral fractures

Purpose

To demonstrate prediction of complications in osteoporotic vertebral fractures with magnetic resonance imaging (MRI) changes over time.

Methods

MRI signal intensities in osteoporotic vertebral fractures were investigated according to the interval between onset and imaging as follows: 0-10 days (early), 11-20 days (middle), and 21-30 days (later).

Results

The diffuse low pattern rates were 52%, 84%, and 95% and 20%, 24%, and 52% in the early, middle, and later periods on T1-WI and T2-WI, respectively.

Conclusions

The diffuse low pattern increased with time. The MRI prediction of complications depends on the time phase.

Network meta-analysis of percutaneous vertebroplasty, percutaneous kyphoplasty, nerve block, and conservative treatment for nonsurgery options of acute/subacute and chronic osteoporotic vertebral compression fractures (OVCFs) in short-term and long-term effects

BACKGROUND

Osteoporotic vertebral compression fractures (OVCFs) commonly afflicts most aged people resulting back pain, substantial vertebral deformity, functional disability, decreased quality of life, and increased adjacent spinal fractures and mortality. Percutaneous vertebral augmentation (PVA) included percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty (PKP), nerve block (NB), and conservative treatment (CT) are used for the nonsurgery treatment strategy of OVCFs, however, current evaluation of their efficacy remains controversial.

METHODS AND ANALYSIS

A systematic literature search was carried out in PubMed, EMBASE, Web of Knowledge, and the Cochrane Central Register of Controlled Trials up to October 31, 2017. Randomized controlled trials (RCTs) were compared PVP, PKP, NB, or CT for treating OVCFs. The risk of bias for each trial was rated according to the Cochrane Handbook. Mean differences (MDs) with 95% confidence intervals (CIs) were utilized to express VAS (visual analog scale) outcomes. The network meta-analysis (NMA) of the comparative efficacy measured by change of VAS on acute/subacute and chronic OVCFs was conducted for a short-term (<4 weeks) and long-term (≥6-12months) follow-up with the ADDIS software.

RESULTS

A total of 18 trials among 1994 patients were included in the NMA. The PVA (PVP and PKP) had better efficacy than CT. PKP was first option in alleviating pain in the case of the acute/subacute OVCFs for long term, and chronic OVCFs for short term and long term, while PVP had the most superiority in the case of the acute/subacute OVCFs for short term. NB ranks higher probability than PKP and PVP on acute/subacute OVCFs in short and long-term, respectively.

CONCLUSIONS

The present results suggest that PVA (PVP/PKP) had better performance than CT in alleviating acute/subacute and chronic OVCFs pain for short and long-term. NB may be used as an alternative or before PVA, as far as pain relief is concerned. Various nonsurgery treatments including CT, PVA (PVP/PKP), NB, or a combination of these treatments are performed with the goal of reducing pain, stabilizing the vertebrae, and restoring mobility.

Safety and efficacy of spinal loop rectangle and sublaminar wires for osteoporotic vertebral compression fracture fixation

Background:

Natural history of osteoporotic vertebral compression fractures (OVCFs), that is, collapse, loads the rigid pedicle screw rod construct in the absence of anterior column reconstruction, often leading to implant back outs. Semi rigid spinal loop rectangle and sublaminar wire construct allows controlled axial collapse and does not require anterior column reconstruction.

Materials and Methods:

This is a retrospective study of 50 consecutive patients of OVCFs. The immediate and final follow-up safety (neurologic deficit, implant failure/back out, revision surgeries, and infection) and efficacy (visual analog scale [VAS] score, axial collapse of the fracture, fracture union and retaining, and the attempted segmental deformity correction) parameters were compared to describe the utility of spinal loop rectangle and sublaminar wiring as a novel, low cost modality of spinal instrumentation for treating OVCFs.

Results:

All the twelve patients with Frankel grade D neurologic deficit improved to Frankel grade E and six patients (out of 8) with Frankel grade C improved to Frankel grade E (and remaining two patients improved to Frankel grade D), following surgery. The average preoperative VAS score of 8.98 (ranging from 5 to 10) improved to 2.76 (ranging from 1 to 10) at final follow-up. Controlled collapse of anterior column, union of OVCF nonunion, and retaining of attempted deformity correction by sublaminar wire anchors cephalad and caudal to the transpedicular decompression was seen in each patient at the final follow-up.

Conclusion:

Spinal loop rectangle and sublaminar wiring construct are viable alternative options for stabilizing OVCFs.

Increased sagittal vertical axis is associated with less effective control of acute pain following vertebroplasty

OBJECTIVES

Although vertebroplasty is very effective for relieving acute pain from an osteoporotic vertebral compression fracture, not all patients who undergo vertebroplasty receive the same degree of benefit from the procedure. In order to identify the ideal candidate for vertebroplasty, pre-operative prognostic demographic or clinico-radiological factors need to be identified. The objective of this study was to identify the pre-operative prognostic factors related to the effect of vertebroplasty on acute pain control using a cohort of surgically and non-surgically managed patients.

PATIENTS AND METHODS

Patients with single-level acute osteoporotic vertebral compression fracture at thoracolumbar junction (T10 to L2) were followed. If the patients were not satisfied with acute pain reduction after a three-week conservative treatment, vertebroplasty was recommended. Pain assessment was carried out at the time of diagnosis, as well as three, four, six, and 12 weeks after the diagnosis. The effect of vertebroplasty, compared with conservative treatment, on back pain (visual analogue score, VAS) was analysed with the use of analysis-of-covariance models that adjusted for pre-operative VAS scores.

RESULTS

A total of 342 patients finished the 12-week follow-up, and 120 patients underwent vertebroplasty (35.1%). The effect of vertebroplasty over conservative treatment was significant regardless of age, body mass index, medical comorbidity, previous fracture, pain duration, bone mineral density, degree of vertebral body compression, and canal encroachment. However, the effect of vertebroplasty was not significant at all time points in patients with increased sagittal vertical axis.

CONCLUSIONS

For single-level acute osteoporotic vertebral compression fractures, the effect of vertebroplasty was less favourable in patients with increased sagittal vertical axis (> 5 cm) possible due to aggravation of kyphotic stress from walking imbalance.Cite this article: Y-C. Kim, D. H. Bok, H-G. Chang, S. W. Kim, M. S. Park, J. K. Oh, J. Kim, T-H. Kim. Increased sagittal vertical axis is associated with less effective control of acute pain following vertebroplasty. Bone Joint Res 2016;5:544-551. DOI: 10.1302/2046-3758.511.BJR-2016-0135.R1.

Osteoporotic thoracolumbar junctional fracture accompanied by spinous process fracture without posterior ligament injury: its clinical and radiologic significances

PURPOSE

To assess the clinical and radiologic outcome of osteoporotic thoracolumbar junctional fracture accompanied by spinous process fracture (SPF) without posterior ligament injury.

METHODS

A total of 391 patients with single-level osteoporotic thoracolumbar junctional (T10-L2) fracture were selectively enrolled. The patients were divided into two groups by absence (group I) or presence (group II) of SPF. Clinical and radiologic parameters were compared between the two groups.

RESULTS

Group I comprised of 332 patients with only vertebral body fracture, and group II comprised of 59 patients with both vertebral body and SPFs. In all cases of group II, SPFs were located just one level above the fractured vertebral body, and the injury of the posterior ligament was not found. At the time of injury, group II patients showed worse outcomes in anterior vertebral body compression percentage, kyphotic Cobb angle, cranial disk status, and the rate of the initial neurologic injury. Kyphotic alignment changes during 1-year follow-up were compared between the conservative subgroups of groups I and II. At the time of injury, there were no statistical differences in anterior vertebral body compression percentage and Cobb angle between the two conservative subgroups. However, the difference was significant after 1-year follow-up. Comparison of kyphotic alignment change at 12 months after diagnosis within group II was done according to the treatment method. Vertebroplasty subgroup in group II did not show benefit even in preventing such kyphotic alignment change, whereas instrumentation subgroup in group II showed lordotic alignment restoration despite more severe kyphotic alignment at the time of injury.

CONCLUSIONS

Osteoporotic thoracolumbar junctional fracture accompanied by spinous process fracture without posterior ligament injury represented more severe injury with flexion forces on the anterior column and tensile forces on the posterior column, and was related with more severe posttraumatic kyphotic changes during the 12-month follow-up.

Pathogenesis of Vertebral Anterior Wedge Deformity: A 2-Stage Process?

STUDY DESIGN

Biomechanical and radiographical study on cadaveric spines.

OBJECTIVE

To explain the pathogenesis of vertebral "anterior wedge" deformity, which causes senile kyphosis.

SUMMARY OF BACKGROUND DATA

This deformity arises with minimal trauma and is difficult to reproduce in cadaveric spines. We hypothesize that wedging is created by a 2-stage process. First, excessive loading damages a vertebral endplate and decompresses the adjacent intervertebral disc. This alters load sharing between the vertebral body cortex and trabeculae so that subsequent cyclic loading causes progressive collapse of the unsupported anterior cortex.

METHODS

Thirty-four cadaveric thoracolumbar "motion segments," aged 70 to 98 years, were positioned in flexion and overloaded in compression. Physiologically reasonable cyclic compressive loading was then applied to each flexed specimen, at progressively higher loads, for up to 2 hours. Before and after initial overload and again after cyclic loading, the distribution of loading on the vertebra was assessed from measurements of compressive stress within the adjacent disc. These "stress profiles" were repeated in the neutral, flexed, and extended postures. Progressive vertebral body deformity was assessed radiographically.

RESULTS

Compressive overload induced endplate fracture at an average force of 2.31 kN. There was minimal anterior wedging, but pressure in the adjacent disc nucleus (in flexion) fell by an average of 55% and neural arch load bearing increased by 166%. Subsequent cyclic loading exaggerated these changes and concentrated compressive stress within the anterior annulus. After both stages, height of the anterior and posterior vertebral cortexes was reduced by 32% and 12%, respectively, so that anterior wedging of the vertebral body increased from 5.0° to 11.4° on average. All changes were highly significant (P < 0.001).

CONCLUSION

Anterior wedge deformities can be created consistently by a 2-stage process involving initial endplate damage, followed by progressive collapse of the anterior cortex. Detecting initial endplate damage may be important to minimize vertebral deformity in patients with osteoporosis.

LEVEL OF EVIDENCE

N/A.