Risk Factors for Residual Back Pain After Balloon Kyphoplasty for Osteoporotic Vertebral Fracture.

Background: Balloon kyphoplasty (BKP) is a method for the management of osteoporotic vertebral body fracture (OVF). However, improvement in back pain (BP) is poor in some patients, also previous reports have not elucidated the exact incidence and risk factors for residual BP after BKP. We clarified the characteristics of residual BP after BKP in patients with OVF. Hypothesis: In this study, we hypothesize that some risk factors may exist for residual BP 2 years after the treatment of OVF with BKP. Patients and Methods: A multicenter cohort study was performed where patients who received BKP within 2 months of OVF injury were followed-up for 2 years. BP at 6 months after surgery and final observation was evaluated by Visual Analog Scale (VAS) score. Patients with a score of 40 mm or more were allocated to the residual BP group, and comparisons between the residual back pain group and the improved group were made for bone density, kyphosis, mobility of the fractured vertebral body, total spinal column alignment, and fracture type (fracture of the posterior element, pedicle fracture, presence or absence of posterior wall damage, etc.). Also, Short Form 36 (SF-36) for physical component summary (PCS) and mental component summary (MCS) at the final follow-up was evaluated in each radiological finding. Results: Of 116 cases, 79 (68%) were followed-up for 2 years. Two years after the BKP, 26 patients (33%) experienced residual BP. Neither age nor sex differed between the groups. In addition, there was no difference in bone mineral density, BKP intervention period (period from onset to BKP), and osteoporosis drug use. However, the preoperative height ratio of the vertebral body was significantly worse in the residual BP group (39.8% vs. 52.1%; p = 0.007). Two years after the operation, the vertebral body wedge angle was significantly greater in the residual BP group (15.7° vs. 11.9°; p = 0.042). In the multiple logistic regression model with a preoperative vertebral body height ratio of 50% or less [calculated by receiver operating characteristic (ROC) curve], the adjusted odds ratio for residual BP was 6.58 (95% confidence interval 1.64-26.30; p = 0.007); similarly, patients with vertebral body height ratio less than 50% had a lower score of SF-36 PCS 24.6 vs. 32.2 p = 0.08. Conclusion: The incidence of residual BP 2 years after BKP was 33% in the current study. The risk factor for residual BP after BKP was a preoperative vertebral body height ratio of 50% or less, which should be attentively assessed for the selection of a proper treatment scheme and to provide adequate stabilization. Level of Evidence: III.

Muscle strength rather than appendicular skeletal muscle mass might affect spinal sagittal alignment, low back pain, and health-related quality of life.

Sarcopenia is defined as decreasing in muscle strength and mass, and dynapenia is defined as decreasing in muscle strength and maintained muscle mass. This study elucidated the prevalence and characteristics of sarcopenia and dynapenia and evaluate in elderly spinal disorders patients. 1039 spinal disorders patients aged ≥ 65 years were included. We measured age, grip strength, muscle mass, spinal sagittal alignment parameters, low back pain (LBP) scores and health-related quality of life (HR-QoL) scores. Based on the previous reports, patients were categorised into normal group: NG, pre-sarcopenia group: PG, dynapenia group: DG, and sarcopenia group: SG. Pre-sarcopenia, dynapenia, and sarcopenia were found in 101 (9.7%), 249 (19.2%), and 91 (8.8%) patients, respectively. The spinal sagittal alignment parameters, trunk muscle mass, LBP, and HR-QoL scores were significantly worse in DG and SG compared with those in PG and NG. Spinal alignment, trunk muscle mass, and clinical outcomes, including LBP and HR-QoL scores, were maintained in the PG and poor in the DG and SG. Thus, intervention for muscle strength may be a treatment option for changes of spinal sagittal alignment and low back pain.

Relationship between body mass index and spinal pathology in community-dwelling older adults.

PURPOSE: To clarify the relationship between body mass index (BMI) and spinal pathologies including spinal sagittal balance, back extensor strength (BES), paraspinal muscle mass, prevalent vertebral fracture, disc degeneration, Modic changes, low back pain, and quality of life (QOL) in community-dwelling older adults. METHODS: This study included 380 participants (age: ≥ 65 years, male/female: 152/228) from the Shiraniwa Study. Multivariate nonlinear regression analysis was used to investigate the relationship between BMI and sagittal vertical axis (SVA), BES, paraspinal muscle mass, visual analog scale (VAS) for low back pain, Oswestry Disability Index (ODI), and EuroQoL-5 Dimension (EQ5D) score after adjusting for sex, age, Hospital Anxiety and Depression Scale score, and Charlson Comorbidity Index. In addition, multiple logistic regression analysis was used to investigate the association between BMI and prevalent vertebral fracture, disc degeneration, and Modic changes. RESULTS: BMI was significantly correlated with SVA, BES, paraspinal muscle mass, VAS, ODI, and EQ5D score. The increase in BMI was associated with the deterioration of all outcomes, which accelerated when the BMI increased from approximately 22-23 kg/m2. Moreover, overweight/obesity was significantly correlated with disc degeneration and Modic changes. CONCLUSION: Increased BMI is significantly associated with spinal pathologies such as SVA, BES, paraspinal muscle mass, VAS, QOL, disc degeneration, and Modic changes. The findings suggest that measures for controlling overweight and obesity among older adults can play an important role in the prevention and treatment of spinal pathologies.

Machine-learning-based approach for nonunion prediction following osteoporotic vertebral fractures.

PURPOSE: An osteoporotic vertebral fracture (OVF) is a common disease that causes disabilities in elderly patients. In particular, patients with nonunion following an OVF often experience severe back pain and require surgical intervention. However, nonunion diagnosis generally takes more than six months. Although several studies have advocated the use of magnetic resonance imaging (MRI) observations as predictive factors, they exhibit insufficient accuracy. The purpose of this study was to create a predictive model for OVF nonunion using machine learning (ML). METHODS: We used datasets from two prospective cohort studies for OVF nonunion prediction based on conservative treatment. Among 573 patients with acute OVFs exceeding 65 years in age enrolled in this study, 505 were analyzed. The demographic data, fracture type, and MRI observations of both studies were analyzed using ML. The ML architecture utilized in this study included a logistic regression model, decision tree, extreme gradient boosting (XGBoost), and random forest (RF). The datasets were processed using Python. RESULTS: The two ML algorithms, XGBoost and RF, exhibited higher area under the receiver operating characteristic curves (AUCs) than the logistic regression and decision tree models (AUC = 0.860 and 0.845 for RF and XGBoost, respectively). The present study found that MRI findings, anterior height ratio, kyphotic angle, BMI, VAS, age, posterior wall injury, fracture level, and smoking habit ranked as important features in the ML algorithms. CONCLUSION: ML-based algorithms might be more effective than conventional methods for nonunion prediction following OVFs.

Decreased muscle mass and strength affected spinal sagittal malalignment.

PURPOSE: Correction surgeries for spinal malalignment showed good clinical outcomes; however, there were concerns including increased invasiveness, complications, and impact on medico-economics. Ideally, an early intervention is needed. To better understand the patho-mechanism and natural course of spinal alignment, the effect of factors such as muscle mass and strength on spinal sagittal imbalance were determined in a multicenter cross-sectional study. METHODS: After excluding metal implant recipients, 1823 of 2551 patients (mean age: 69.2 ± 13.8 years; men 768, women 1055) were enrolled. Age, sex, past medical history (Charlson comorbidity index), body mass index (BMI), grip strength (GS), and trunk muscle mass (TM) were reviewed. Spinal sagittal imbalance was determined by the SRS-Schwab classification. Multiple comparison analysis among four groups (Normal, Mild, Moderate, Severe) and multinomial logistic regression analysis were performed. RESULTS: On multiple comparison analysis, with progressing spinal malalignment, age in both sexes tended to be higher; further, TM in women and GS in both sexes tended to be low. On multinomial logistic regression analysis, age and BMI were positively associated with spinal sagittal malalignment in Mild, Moderate, and Severe groups. TM in Moderate and Severe groups and GS in the Moderate group were negatively associated with spinal sagittal malalignment. CONCLUSION: Aging, obesity, low TM, and low GS are potential risk factors for spinal sagittal malalignment. Especially, low TM and low GS are potentially associated with more progressed spinal sagittal malalignment. Thus, early intervention for muscles, such as exercise therapy, is needed, while the spinal sagittal alignment is normal or mildly affected.

Trunk Muscle Mass Measured by Bioelectrical Impedance Analysis Reflecting the Cross-Sectional Area of the Paravertebral Muscles and Back Muscle Strength: A Cross-Sectional Analysis of a Prospective Cohort Study of Elderly Population.

Trunk muscles play an important role in supporting the spinal column. A decline in trunk muscle mass, as measured by bioelectrical impedance analysis (TMM-BIA), is associated with low back pain and poor quality of life. The purpose of this study was to determine whether TMM-BIA correlates with quantitative and functional assessments traditionally used for the trunk muscles. We included 380 participants (aged ≥ 65 years; 152 males, 228 females) from the Shiraniwa Elderly Cohort (Shiraniwa) study, for whom the following data were available: TMM-BIA, lumbar magnetic resonance imaging (MRI), and back muscle strength (BMS). We measured the cross-sectional area (CSA) and fat-free CSA of the paravertebral muscles (PVM), including the erector spinae (ES), multifidus (MF), and psoas major (PM), on an axial lumbar MRI at L3/4. The correlation between TMM-BIA and the CSA of PVM, fat-free CSA of PVM, and BMS was investigated. TMM-BIA correlated with the CSA of total PVM and each individual PVM. A stronger correlation between TMM-BIA and fat-free CSA of PVM was observed. The TMM-BIA also strongly correlated with BMS. TMM-BIA is an easy and reliable way to evaluate the trunk muscle mass in a clinical setting.

Gender-specific analysis for the association between trunk muscle mass and spinal pathologies.

We investigated the relationship between trunk muscle mass and spinal pathologies by gender. This multicenter cross-sectional study included patients aged ≥ 30 years who visited a spinal outpatient clinic. Trunk and appendicular muscle mass were measured using bioelectrical impedance analysis. The Oswestry Disability Index (ODI), visual analog scale (VAS) score for low back pain, sagittal vertical axis (SVA), and EuroQol 5 Dimension (EQ5D) score were investigated to evaluate spinal pathology. The association between trunk muscle mass and these parameters was analyzed by gender using a non-linear regression model adjusted for patients' demographics. We investigated the association between age and trunk muscle mass. We included 781 men and 957 women. Trunk muscle mass differed significantly between men and women, although it decreased with age after age 70 in both genders. Lower trunk muscle mass was significantly associated with ODI, SVA, and EQ5D score deterioration in both genders; its association with VAS was significant only in men. Most parameters deteriorated when trunk muscle mass was < 26 kg in men and < 19 kg in women. Lower trunk muscle mass was associated with lumbar disability, spinal imbalance, and poor quality of life in both genders, with significant difference in muscle mass.

Using artificial intelligence to diagnose fresh osteoporotic vertebral fractures on magnetic resonance images.

BACKGROUND CONTEXT: Accurate diagnosis of osteoporotic vertebral fracture (OVF) is important for improving treatment outcomes; however, the gold standard has not been established yet. A deep-learning approach based on convolutional neural network (CNN) has attracted attention in the medical imaging field. PURPOSE: To construct a CNN to detect fresh OVF on magnetic resonance (MR) images. STUDY DESIGN/SETTING: Retrospective analysis of MR images PATIENT SAMPLE: This retrospective study included 814 patients with fresh OVF. For CNN training and validation, 1624 slices of T1-weighted MR image were obtained and used. OUTCOME MEASURE: We plotted the receiver operating characteristic (ROC) curve and calculated the area under the curve (AUC) in order to evaluate the performance of the CNN. Consequently, the sensitivity, specificity, and accuracy of the diagnosis by CNN and that of the two spine surgeons were compared. METHODS: We constructed an optimal model using ensemble method by combining nine types of CNNs to detect fresh OVFs. Furthermore, two spine surgeons independently evaluated 100 vertebrae, which were randomly extracted from test data. RESULTS: The ensemble method using VGG16, VGG19, DenseNet201, and ResNet50 was the combination with the highest AUC of ROC curves. The AUC was 0.949. The evaluation metrics of the diagnosis (CNN/surgeon 1/surgeon 2) for 100 vertebrae were as follows: sensitivity: 88.1%/88.1%/100%; specificity: 87.9%/86.2%/65.5%; accuracy: 88.0%/87.0%/80.0%. CONCLUSIONS: In detecting fresh OVF using MR images, the performance of the CNN was comparable to that of two spine surgeons.

Risk factors of the poor long-term prognosis of osteoporotic vertebral fractures: A multicenter cohort study.

INTRODUCTION: The presence of existing osteoporotic vertebral fracture (OVF) increases the mortality risk. However, the influence of the characteristics of OVF is unclear. This study aimed to investigate the influence of new OVF on patients' long-term prognosis using our past cohort study. METHOD: This is an extension study of our cohort study carried out between 2005 and 2007. In the present extension study, of 420 patients, 197 whose contact information was available at the 6-month follow-up were included in the telephone survey in 2018. Five patients refused to participate in the survey, and 82 could not be contacted. Eventually, 110 patients were enrolled. Of the Demographic data, radiological findings, medical history, and clinical outcome were investigated at injury onset and at the 6-month follow-up. A proportional hazard model was used to investigate the risk factors for mortality. RESULTS: Among 110 patients, 33 died. Male sex and low body mass index (BMI <18.5 kg/m2) were significant risk factors for mortality [hazard ratio (HR) = 6.40, 1.01-40.50; 5.24, 1.44-19.04, respectively]. The history of stroke and liver disease increased the risk of mortality (HR = 13.37, 1.93-92.7; 6.62, 1.15-38.14, respectively). As regards radiological findings, local kyphosis progression per 1° or ≥7° were significant risk factors of mortality (HR = 1.20, 1.06-1.36; 5.38, 1.81-16.03, respectively). CONCLUSIONS: A telephone survey at 12 years after the occurrence of OVF analyzed risk factors for mortality and showed that a progression of local kyphosis in fractures between injury onset and 6 months after injury was a risk factor of poor prognosis.

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.

Relationship of back muscle and knee extensors with the compensatory mechanism of sagittal alignment in a community-dwelling elderly population.

Compensatory mechanisms, such as a decrease in thoracic spine kyphosis and posterior tilting or rotation of the pelvis, aim to achieve optimal alignment of the spine. However, the effect of muscle strength on these compensatory mechanisms has not been elucidated. This study aimed to investigate the impact of back muscle and lower extremity strength on compensatory mechanisms in elderly people. Overall, 409 community-dwelling elderly participants (164 men, 245 women) were included. Age, disc degeneration, and 2 or more vertebral fractures showed a significant increase of risk for sagittal vertical axis (SVA) deterioration. Conversely, stronger back, hip flexor, and knee extensor muscles reduced the risk for SVA deterioration. To investigate the association of each muscle's strength with compensatory mechanisms, 162 subjects with pelvic incidence-lumbar lordosis > 10° were selected. The linear regression model for thoracic kyphosis demonstrated a negative correlation with back muscle strength and positive correlation with vertebral fracture. The regression analysis for pelvic tilt demonstrated a positive correlation with knee extensor strength. Back, hip flexor, and knee extensor muscle strength were associated with sagittal spinal alignment. Back muscle strength was important for the decrease in thoracic kyphosis, and knee extensor strength was associated with pelvic tilt.

Presence of sarcopenia does not affect the clinical results of balloon kyphoplasty for acute osteoporotic vertebral fracture.

Sarcopenia has been associated with poor clinical outcomes in several diseases. Herein, the clinical results of balloon kyphoplasty (BKP) for acute osteoporotic vertebral fracture (OVF) treatment were assessed and compared between sarcopenia and non-sarcopenia patients. Sixty patients who underwent BKP for treatment of acute OVF with poor prognostic factors between April 2016 and September 2017 and were assessed for sarcopenia were enrolled. Clinical results (back pain on visual analogue scale [VAS]; short-form [SF] 36; vertebral deformity; activities of daily living levels; and incidence of adjacent vertebral fractures) were compared between the two groups at 6 months post-BKP. Data analysis revealed that back pain on VAS, SF-36 scores, and vertebral deformity improved from baseline to 6 months after BKP. Thirty-nine patients (65.0%) were diagnosed with sarcopenia and demonstrated a lower body mass index (21.2 vs. 23.3 kg/m2, p = 0.02), skeletal muscle mass index (5.32 vs. 6.55 kg/m2, p < 0.01), hand-grip strength (14.7 vs. 19.2 kg, p = 0.01), and bone mineral density of the femoral neck (0.57 vs. 0.76 g/cm2, p < 0.01) than those of patients without sarcopenia. However, no significant differences were observed in the clinical results between these groups. Therefore, BKP's clinical results for the treatment of acute OVF are not associated with sarcopenia.

Impact of paravertebral muscle in thoracolumbar and lower lumbar regions on outcomes following osteoporotic vertebral fracture: a multicenter cohort study.

We investigated the effect of paravertebral muscle (PVM) on poor prognosis in osteoporotic vertebral fracture (OVF) and remaining lower back pain (LBP) in the thoracolumbar and lower lumbar regions. Additional OVF occurrence in the thoracolumbar and remaining LBP in the lumbar region was significantly related to PVM fat infiltration percentage. PURPOSE: Paravertebral muscle (PVM) is an important component of the spinal column. However, its role in the healing process after osteoporotic vertebral fracture (OVF) is unclear. This study aimed to clarify the effect of PVM in thoracolumbar and lower lumbar regions on OVF clinical and radiological outcomes. METHODS: This was a multicenter prospective cohort study from 2012 to 2015. Patients ≥ 65 years old who presented within 2 weeks after fracture onset were followed up for 6 months. PVM was measured at the upper edge of the L1 and L5 vertebral body in the magnetic resonance imaging (MRI) T2-axial position at registration. The cross-sectional area (CSA), relative CSA (rCSA), and fat infiltration percentage (FI%) were measured. Severe vertebral compression, delayed union, new OVF, and remaining low back pain (LBP) were analyzed. RESULTS: Among 153 patients who were followed up for 6 months, 117 with measurable PVM were analyzed. Their average age was 79.1 ± 7.2 years, and 94 were women (80.3%). There were 48 cases of severe vertebral compression, 21 delayed unions, 11 new OVF, and 27 remaining LBP. Among all poor prognoses, only the FI% of the PVM was significantly associated with new OVF (p = 0.047) in the thoracolumbar region and remaining LBP (p = 0.042) in the lumbar region. CONCLUSION: The occurrence of additional OVF in the thoracolumbar region and remaining LBP in the lumbar region was significantly related to the FI% of the PVM. Physicians should be aware that patients with such fatty degeneration shown in acute MRI may require stronger treatment.

Predictors of dropout from cohort study due to deterioration in health status, with focus on sarcopenia, locomotive syndrome, and frailty: From the Shiraniwa Elderly Cohort (Shiraniwa) study.

BACKGROUND: Conditions of the elderly like sarcopenia, locomotive syndrome, and frailty have been attracting attention recently. However, the relationship of these 3 conditions and the difference in the magnitude of influence each has on deterioration in health status remain unclear. The purpose of this study was to investigate the prevalence and relationship of sarcopenia, locomotive syndrome, and frailty, and to clarify their influence on the dropout from cohort study due to deterioration in health status. METHODS: The 1st survey of the Shiraniwa Elderly Cohort (Shiraniwa) study was conducted in 2016. We examined 409 participants (aged ≥ 65 years; 164 males, 245 females) and assessed sarcopenia, locomotive syndrome, and frailty. Those who could not attend the 2nd survey (2017) due to deterioration in health status were defined as the Dropout group. We investigated the predictors of Dropout using multiple logistic regression analysis. RESULTS: The prevalence of sarcopenia, locomotive syndrome stage 2, and frailty were 4.4%, 40.1%, and 14.2%, respectively; 89.7% of participants with frailty were also diagnosed with locomotive syndrome stage 2. From the results of the 2nd survey, 46 people were classified into the Dropout group. Independent predictors of the Dropout were locomotive syndrome stage 2 (adjusted odds ratio [OR]: 2.42, 95% confidence interval [CI]: 1.11-5.31) and frailty (adjusted OR: 3.37, 95%CI: 1.56-7.30). CONCLUSIONS: Locomotive syndrome stage 2 was the most common condition in the elderly, and most people with frailty also had locomotive syndrome stage 2. Locomotive syndrome stage 2 and frailty independently influenced the dropout from cohort study due to deterioration in health status. These results suggest that screening for locomotive syndrome is useful for early detection of the elderly with a risk of deterioration in health status, and screening for frailty may contribute to detecting the elderly with higher risk of deterioration in health status.

Characteristic radiological findings for revision surgery after balloon kyphoplasty.

Balloon kyphoplasty (BKP) sometimes fails to improve patients' outcomes, with revision surgery, using anterior or posterior reconstruction, being required. The purpose of this study was to investigate the radiological risk factors of failure after BKP in the treatment of osteoporotic vertebral fractures (OVFs). This case-control study included 105 patients treated with single BKP and 14 patients  who required revision BKP. We evaluated radiological findings differentiating both groups, using plain radiography and computed tomography, before BKP. Angular flexion-extension motion was significantly greater in the revision than BKP group. While the frequency of pedicle fracture and posterior wall injury was not different between the groups, a split type fracture was more frequent in the revision group. Split type fracture had the highest adjusted odds ratio (OR) for revision (16.5, p = 0.018). Angular motion ≥14° increased the risk for revision surgery by 6-fold (p = 0.013), with endplate deficit having an OR of revision of 5.0 (p = 0.032). The revision rate after BKP was 3.8%, with split type fracture, greater angular motion and large endplate deficit being risk factors for revision. Treatment strategies for patients with these risk factors should be carefully evaluated, considering the inherent difficulties in performing revision surgery after BKP.

Development of a scoring system for predicting adjacent vertebral fracture after balloon kyphoplasty.

BACKGROUND CONTEXT: The incidence of adjacent vertebral fracture (AVFs) is reported to be 10%-38% after balloon kyphoplasty. However, no reports have established a system for prediction of AVF occurrence. PURPOSE: To establish a scoring system for predicting AVF occurrence after balloon kyphoplasty for osteoporotic vertebral fractures (OVFs). DESIGN: A prospective cohort study. PATIENT SAMPLE: Consecutive elderly patients aged 65 years and older who underwent balloon kyphoplasty for OVFs within 2 months after the onset. OUTCOME MEASURES: AVF was confirmed by X-ray. METHODS: From 2015 to 2017, 116 consecutive patients from 10 participating hospitals who underwent balloon kyphoplasty were enrolled in this study. Prior to study enrollment, each patient underwent plain X-ray, computed tomography (CT), and magnetic resonance imaging (MRI) of the thoracic and lumbar spine. Severity of pain was subjectively assessed using a visual analog scale (VAS) based on the average level of back pain that the patient had experienced in the preceding week. After enrollment, subjects underwent balloon kyphoplasty. Quality of life was evaluated using SF-36. Patients were followed up for at least 6 months. RESULTS: Of the 116 patients enrolled, 109 patients with all the required data at the time of enrolment and the 6-month follow-up were included in the study. A total of 32 patients (29%) showed AVFs within the 6-month follow-up. No significant differences were observed in each clinical outcome at 6-month follow-up, although higher VAS score for back pain at 1-month follow-up was observed in the AVF group (37.5) than in the non-AVF group (20.8, p<.001). Wedge angle of vertebrae before surgery was greater in the AVF group (21.6°) than in the non-AVF group (15.7°, p<.001). The change in wedge angle between pre- and postsurgery was greater in the AVF group than in the non-AVF group, whereas the change in local kyphosis was not significantly different. The multiple logistic regression model showed increased odds ratio (OR) of thoracic or thoracolumbar spine, old OVF presence, >25° kyphosis before surgery, and >10°correction for AVF. Based on this result, a simple scoring system for predicting AVF occurrence was developed. The total AVF score was calculated as the sum of the individual scores, which varied from 0 to 6. All patients with 5-6 points sustained AVF. CONCLUSIONS: More severe wedge angle before surgery, correction degree, old OVF presence, and thoracolumbar level were predictive factors for AVF. All patients with AVF risk score of 5 or more showed AVF. This information may aid preoperative risk assessment, informed shared decision-making, and consideration of potential alternative management strategies.

ISSLS PRIZE IN CLINICAL SCIENCE 2019: clinical importance of trunk muscle mass for low back pain, spinal balance, and quality of life-a multicenter cross-sectional study.

STUDY DESIGN: A multicenter cross-sectional study. OBJECTIVES: To clarify the relationship of trunk muscle mass with low back pain, spinal sagittal balance, and quality of life. Few reports have investigated the relationship of trunk muscle mass with lumbar spine function and spinal balance, and the clinical significance of trunk muscle mass remains unclear. METHODS: Patients attending spinal outpatient clinics at 10 different medical institutions were enrolled in this study. Patient demographics, trunk muscle mass and appendicular skeletal muscle mass (ASM) measured by bioelectrical impedance analysis (BIA), body mass index (BMI), Charlson Comorbidity Index (CCI), the Oswestry Disability Index (ODI), visual analog scale (VAS) for low back pain, sagittal vertical axis (SVA), and EuroQol 5 Dimension (EQ5D) score were investigated. Multivariate nonlinear regression analysis was used to investigate the association of trunk muscle mass with the ODI, VAS score, SVA, and EQ5D score. RESULTS: Of 2551 eligible patients, 1738 (mean age 70.2 ± 11.0 years; 781 men and 957 women) were enrolled. Trunk muscle mass was significantly correlated with the ODI, VAS score, SVA, and EQ5D score (P < 0.001) when adjusted for age, sex, BMI, ASM, CCI, and history of lumbar surgery. Patient deterioration was associated with a decrease in trunk muscle mass, and the deterioration accelerated from approximately 23 kg. CONCLUSIONS: Trunk muscle mass was significantly associated with the ODI, VAS score, SVA, and EQ5D score. Trunk muscle mass may assume an important role to elucidate and treat lumbar spinal dysfunction and spinal imbalance. These slides can be retrieved under Electronic Supplementary Material.

Association between MRI findings and back pain after osteoporotic vertebral fractures: a multicenter prospective cohort study.

BACKGROUND CONTEXT: Osteoprotic vertebral fractures (OVFs) are common in elderly people. The association between back pain due to OVF with magnetic resonance imaging (MRI) signal change is unclear. In this study we hypothesized that MRI findings would be a predictive factor for back pain measured by visual analogue scale (VAS) at 6 months follow-up. PURPOSE: The aim was to study the MRI findings that predict back pain after OVF and the association between radiological findings and scores of back pain. STUDY DESIGN: Multicenter prospective cohort study. PATIENT SAMPLE: A total of 153 OVF patients. OUTCOME MEASURE: The outcome measures were VAS back pain and MRI signal change. METHODS: This study was performed from 2012 to 2015. Consecutive patients with less than 2-week-old OVFs at 11 institutions were enrolled prospectively. MRI was performed at enrollment and at 1, 3, and 6 months follow-up. T1- and T2-weighted images (T1WI and T2W1) were obtained at each time point and their association with VAS scores of back pain at 6 months were investigated. Anterior compression ratio, posterior compression ratio, and angular motion of vertebral bodies were also measured on X-rays at each follow-up. This research had no financial support. There are no conflicts of interest. RESULT: The 6 months follow-up was completed by 153 patients. At enrollment, the average VAS score of back pain was 75 mm, and it had improved at the 6-month follow-up to an average score of 20 mm. There was a significant correlation between T1 diffuse low signal change and VAS scores at the 6-month follow-up (p<.01). T2 high signal changes (odds ratio; 4.01, p<.01) and old vertebral fractures (odds ratio; 2.47, p=.04) were independent risk factors for back pain. The correlation between angular motion of vertebrae on X-rays and the VAS score of back pain was significant at all time points. CONCLUSION: This study demonstrates the radiological factors associated with persistent back pain after an OVF and the association between the VAS score of back pain and radiological findings. In addition, T2 high signal changes in acute phase and old vertebral fractures were independent risk factors for residual back pain.

Cost-effectiveness of Balloon Kyphoplasty for Patients With Acute/Subacute Osteoporotic Vertebral Fractures in the Super-Aging Japanese Society.

STUDY DESIGN: A propensity score matching study. OBJECTIVE: The aim of this study was to assess the cost-effectiveness of balloon kyphoplasty (BKP) in Japan. SUMMARY OF BACKGROUND DATA: Osteoporotic vertebral fracture (OVF) is a common disease in elderly people. In Japan, the incidence of painful OVF in 2008 was estimated as 880,000, and approximately 40% of patients with painful OVF are hospitalized due to the severity of pain. Japan is the front runner among super-aged societies and rising health care costs are an economic problem. METHODS: BKP and nonsurgical management (NSM) for acute/subacute OVF were performed in 116 and 420 cases, respectively. Quality-adjusted life years (QALY) and incremental costs were calculated on the basis of a propensity score matching study. QALY was evaluated using the SF-6D questionnaire. Finally, using a Markov model, incremental cost-effectiveness ratios (ICERs) were calculated for 71 matched cases. RESULTS: In the comparison between BKP and NSM, mean patients age was 78.3 and 77.7 years, respectively (P = 0.456). The BKP procedure cost 402,988 JPY more than NSM and the gains in QALY at the 6-month follow-up were 0.153 and 0.120, respectively (difference = 0.033). ICERs for 3 and 20 years were 4,404,158 JPY and 2,416,406 JPY, respectively. According to sensitivity analysis, ICERs ranged from 652,181 JPY to 4,896,645 JPY (4418-33,168 GBP). CONCLUSION: This study demonstrated that BKP is a cost-effective treatment option for OVF in Japan. However, the effect might be blunted in patients aged > 80 years. Further research is necessary to elucidate the cost-effectiveness of BKP in this population. LEVEL OF EVIDENCE: 4.

Balloon Kyphoplasty Versus Conservative Treatment for Acute Osteoporotic Vertebral Fractures With Poor Prognostic Factors: Propensity Score Matched Analysis Using Data From Two Prospective Multicenter Studies.

STUDY DESIGN: A multicenter, prospective, single-arm, intervention study. OBJECTIVE: The aim of this study was to investigate efficacy of balloon kyphoplasty (BKP) for acute osteoporotic vertebral fractures (OVFs) in patients with poor prognostic factors. SUMMARY OF BACKGROUND DATA: The indications for BKP remain unclear. Characteristic magnetic resonance imaging (MRI) findings (high-intensity or diffuse low-intensity area in fractured vertebrae on T2-weighted images) were reportedly predictive of delayed union. METHODS: This study enrolled 106 patients with poor prognostic MRI findings who underwent BKP within 2 months after injury, and 116 controls with acute OVFs and the same poor prognostic factors who underwent conservative treatment. Patients were propensity score matched in a logistic regression model adjusted for age, sex, number of baseline old fractures, and fracture level. The primary outcome was reduction in activities of daily living (ADLs) at 6 months after fracture, and the secondary outcomes were improvement in short-form (SF)-36 subscales, back pain visual analog scale (VAS) score, and vertebral body deformity. RESULTS: A decrease in ADLs occurred in 5.6% of patients in the BKP group and 25.6% of patients in the conservative treatment group (P < 0.001). The SF-36 vitality subscale score improved by 26.9 ±â€Š25.9 points in the BKP group and 14.5 ±â€Š29.4 points in the control group (P = 0.03). The VAS pain score improved by 43.4 ±â€Š34.4 in the BKP group and 52.2 ±â€Š29.8 in the control group (P = 0.44). The vertebral body wedge angle improved by 5.5 ±â€Š6.2° in the BKP group and -6.3 ±â€Š5.0° in the control group (P < 0.0001). The percent vertebral body height improved by 15.2 ±â€Š19.2% in the BKP group and -20.6 ±â€Š14.2% in the control group (P < 0.0001). CONCLUSION: ADLs, quality of life, and vertebral deformity showed greater improvement with BKP intervention for acute OVF with poor prognostic factors than with conservative treatment at 6 months after injury. Our treatment strategy uses BKP intervention according to the presence or absence of poor prognostic MRI findings. LEVEL OF EVIDENCE: 4.