Assessing the Impact of Preoperative MRI-Based Vertebral Bone Quality Scores on 5-Year Prognosis in Lumbar Spine Surgery.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To assess the utility of preoperative vertebral bone quality (VBQ) scores in predicting the 5-year clinical outcomes following lumbar spine surgery. SUMMARY OF BACKGROUND DATA: Osteoporosis poses a significant concern in older adults undergoing spinal surgery. The VBQ score, assessed through preoperative magnetic resonance imaging (MRI), is associated with subsequent osteoporotic fractures and postoperative complications. However, previous report on the impact of VBQ score on mid-term clinical outcomes after lumbar spine surgery remains lacking. METHODS: A total of 189 patients who underwent lumbar surgery (≤3-disc levels) for lumbar spinal stenosis between 2010 and 2016 were enrolled. Patients were classified into high (>3.35), middle (2.75 to 3.35), and low (<2.73) VBQ score groups based on tertiles. Clinical scores, including Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and Short Form-36 (SF-36), were recorded preoperatively and 1, 2, and 5 years postoperatively. RESULTS: Comparative analysis showed significant differences among the VBQ groups throughout the study period in low back pain (P=0.013), walking ability (P=0.005), social life function (P=0.010) of JOABPEQ, and physical component summary of the SF-36 (P=0.018) following lumbar spine surgery. A higher VBQ score was significantly correlated with worse 5-year postoperative outcomes for all domains except for lumbar function of the JOABPEQ using multiple linear regression analysis, adjusting for age, sex, BMI, hyperlipidemia, surgical procedures, and each preoperative score. CONCLUSION: A high preoperative VBQ score is a risk factor for poor 5-year clinical outcomes after lumbar spine surgery. Evaluation of the VBQ score through routine preoperative MRI facilitates osteoporotic screening in lumbar patients without radiation exposure and healthcare costs, while also demonstrating its potential as a prognostic indicator of postoperative clinical outcomes. LEVEL OF EVIDENCE: 3.

Short-Term Risk Factors for Distal Junctional Kyphosis after Spinal Reconstruction Surgery in Patients with Osteoporotic Vertebrae.

STUDY DESIGN: Level 3 retrospective cohort case-control study. PURPOSE: This study aimed to investigate the risk factors for distal junctional kyphosis (DJK) caused by osteoporotic vertebral fractures following spinal reconstruction surgery, with a focus on the sagittal stable vertebra. OVERVIEW OF LITERATURE: Despite the rarity of reports on DJK in this setting, DJK was reported to reduce when the lower instrumented vertebra (LIV) was extended to the sagittal stable vertebra in the posterior corrective fixation for Scheuermann's disease. METHODS: This study included 46 patients who underwent spinal reconstruction surgery for thoracolumbar osteoporotic vertebral fractures and kyphosis and were followed up for 1 year postoperatively. DJK was defined as an advanced kyphosis angle >10° between the LIV and one lower vertebra. The patients were divided into groups with and without DJK. The risk factors of the two groups, such as patient background, surgery-related factors, radiographic parameters, and clinical outcomes, were analyzed. RESULTS: The DJK and non-DJK groups included 14 and 32 patients, respectively, without significant differences in patient background. Those with instability in the distal adjacent LIV disc had a significantly higher risk of DJK occurrence (28.6% vs. 3.2%, p=0.027). DJK occurrence significantly increased in those with the sagittal stable vertebra not included in the fixation range (57.1% vs. 18.8%, p=0.020). Other preoperative radiographic parameters were not significantly different. Instability in the distal adjacent LIV disc (adjusted odds ratio, 14.50; p=0.029) and the exclusion of the sagittal stable vertebra from the fixation range (adjusted odds ratio, 5.29; p=0.020) were significant risk factors for DJK occurrence. CONCLUSIONS: Regarding spinal reconstruction surgery in patients with osteoporotic vertebral fractures, instability in the distal adjacent LIV disc and the exclusion of the sagittal stable vertebra from the fixation range were risk factors for DJK occurrence in the short term.

Impact of Incident Osteoporotic Vertebral Fractures on 5-Year Postoperative Outcomes and Spinal Alignment Following Lumbar Fusion Surgery.

Introduction: Osteoporotic vertebral fractures (OVFs) are a significant problem among older patients who are undergoing spine surgery. This study examined the influence of incident OVFs on clinical outcomes and spinal alignment 5 years following short-segment fusion (SSF) for lumbar spinal stenosis. Methods: We studied 88 patients who underwent SSF (≤2-disc level) for lumbar spinal stenosis with instability and were followed up for more than 5 years postoperatively. Those with prior OVFs were excluded. We evaluated incident OVFs with plain whole-spine lateral radiography preoperatively (before) and at 5 years postoperatively (after). Using preoperative lumbar computed tomography, Hounsfield unit (HU) values were evaluated. The patients were classified into two groups according to the presence of incident OVFs. Repeated-measures analysis of variance was utilized to compare the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and the 36-item Short-Form Health Survey (SF-36), and spinal parameters were recorded before and after. Multiple linear regression analyses were employed to investigate the association between the incident OVFs and the clinical scores and spinal alignment recorded after. Results: In the fracture group, the clinical course of low back pain score on the JOABPEQ, physical component summary SF-36 score, and spinal alignment including C7 sagittal vertical axis (SVA), thoracic kyphosis (TK), and pelvic tilt were significantly worse. Multiple linear regression revealed a significant correlation between incident OVFs and worse 5-year postoperative spinal alignment, which includes SVA and TK. The optimal threshold for the HU values for predicting the incidence of OVFs within 5 years postoperatively was 83.0 (area under the curve 0.701). Conclusions: Incident OVFs in patients following SSF were significantly correlated with the 5-year clinical outcomes and spinal alignment. Patients at risk of OVFs, especially those with HU values below 83, must take preventive measures against OVFs, as this could prevent deteriorating midterm postoperative clinical outcomes and spinal alignment. Level of Evidence: 3.

Degeneration of Cervical Multifidus Muscles Negatively Affects Physical Activity-related Quality of Life After Laminoplasty for Degenerative Cervical Myelopathy.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: The study aimed to investigate the related factors affecting physical activity-related quality of life (QOL) after 2 years of cervical laminoplasty for degenerative cervical myelopathy (DCM), focusing on the degree of preoperative degeneration of the cervical multifidus muscles. SUMMARY OF BACKGROUND DATA: The association between paraspinal muscle degeneration and clinical outcomes after spinal surgery is being investigated. The effect of preoperative degeneration of the cervical multifidus muscles in patients undergoing cervical laminoplasty is ambiguous. METHODS: Patients who underwent laminoplasty for DCM and followed up for more than 2 years were reviewed. To evaluate physical QOL, the physical component summary (PCS) of the 36-Item Short-Form Health Survey (SF-36) was recorded at 2 years postoperatively. The degree of preoperative degeneration in the multifidus muscles at the C4 and C7 levels on axial T2-weighted magnetic resonance imaging (MRI) was categorized according to the Goutallier grading system. The correlation between 2-year postoperative PCS and each preoperative clinical outcome, radiographic parameter, and MRI finding, including Goutallier classification, was analyzed. Variables with a P value <0.10 in univariate analysis were included in multiple linear regression analysis. RESULTS: In total, 106 consecutive patients were included. The 2-year postoperative PCS demonstrated significant correlation with age (R=-0.358, P=0.002), preoperative JOA score (R=0.286, P=0.021), preoperative PCS (R=0.603, P<0.001), C2-C7 lordotic angle (R=-0.284, P=0.017), stenosis severity (R=-0.271, P=0.019), and Goutallier classification at the C7 level (R=-0.268, P=0.021). In multiple linear regression analysis, sex (ß=-0.334, P=0.002), age (ß=-0.299, P=0.013), preoperative PCS (ß=0.356, P=0.009), and Goutallier classification at the C7 level (ß=-0.280, P=0.018) were significantly related to 2-year postoperative PCS. CONCLUSIONS: Increased degeneration of the multifidus muscle at the C7 level negatively affected physical activity-related QOL postoperatively. These results may guide spine surgeons in predicting physical activity-related QOL in patients with DCM after laminoplasty. LEVEL OF EVIDENCE: Level III.

Lower preoperative Hounsfield unit values as a risk factor for poor 5-year clinical outcomes after lumbar spine surgery.

OBJECTIVE: Hounsfield Unit (HU) value has been associated with future osteoporotic fractures and postoperative complications. However, no studies on the impact of low HU values on mid-term clinical outcomes following lumbar spine surgery have been reported. We aimed to evaluate the usefulness of preoperative HU values for 5-year clinical outcomes following lumbar spine surgery. METHODS: We enrolled 200 patients who underwent lumbar surgery (≤ 3-disc levels) for lumbar spinal stenosis. HU values were assessed using preoperative lumbar computed tomography as part of routine preoperative planning for lumbar surgery. Patients were divided into two groups based on the cutoff value of the HU values obtained from the receiver operating characteristic curve for the incidence of vertebral fractures within five years postoperatively. Clinical scores preoperatively and 1, 2, and 5 years postoperatively, including Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and Short Form-36 (SF-36), were compared using a mixed-effects model. RESULTS: Comparative analysis indicated that all domains of JOABPEQ, except for lumbar function, and the physical component summary of the SF-36 were significantly worse in the low HU group than in the high HU group. Using multiple regression analysis, low HU values were significantly correlated with worse 5-year postoperative scores in all domains of JOABPEQ and SF-36. CONCLUSION: Low preoperative HU values are a risk factor for poor 5-year clinical outcomes after lumbar spine surgery. HU values are not only a valuable tool for analyzing bone mineral density but also may be a valuable poor prognostic factor of postoperative clinical outcomes.

Residual Paresthesia After Surgery for Degenerative Cervical Myelopathy: Incidence and Impact on Clinical Outcomes and Satisfaction.

STUDY DESIGN: Multicenter, prospective cohort study. OBJECTIVE: The current study aimed to identify the incidence of residual paresthesias after surgery for degenerative cervical myelopathy (DCM), and to demonstrate the impact of these symptoms on clinical outcomes and patient satisfaction. SUMMARY OF BACKGROUND DATA: Surgery for DCM aims to improve and/or prevent further deterioration of physical function and quality-of-life (QOL) in the setting of DCM. However, patients are often not satisfied with their treatment for myelopathy when they have severe residual paresthesias, even when physical function and QOL are improved after surgery. MATERIALS AND METHODS: The authors included 187 patients who underwent laminoplasty for DCM. All patients were divided into two groups based on their visual analog scale score for paresthesia of the upper extremities at one year postoperatively (>40 vs. ≤40 mm). Preoperative factors, changes in clinical scores and radiographic factors, and satisfaction scales at one year postoperatively were compared between groups. The authors used mixed-effect linear and logistic regression modeling to adjust for confounders. RESULTS: Overall, 86 of 187 patients had severe residual paresthesia at one year postoperatively. Preoperative patient-oriented pain scale scores were significantly associated with postoperative residual paresthesia ( P =0.032). A mixed-effect model demonstrated that patients with severe postoperative residual paresthesia showed significantly smaller improvements in QOL ( P =0.046) and myelopathy ( P =0.037) than patients with no/mild residual paresthesia. Logistic regression analysis identified that residual paresthesia was significantly associated with lower treatment satisfaction, independent of improvements in myelopathy and QOL (adjusted odds ratio: 2.5, P =0.010). CONCLUSION: In total, 45% of patients with DCM demonstrated severe residual paresthesia at one year postoperatively. These patients showed significantly worse treatment satisfaction, even after accounting for improvements in myelopathy and QOL. As such, in patients who experience higher preoperative pain, multidisciplinary approaches for residual paresthesia, including medications for neuropathic pain, might lead to greater clinical satisfaction. LEVEL OF EVIDENCE: 3.

Factors Predicting the Final Diagnosis in Image-Guided Percutaneous Needle Biopsy for Suspected Spinal Tumors.

In cases of suspected spinal tumors on imaging studies, a biopsy is often necessary for establishing the diagnosis. Predictive factors for tumors or malignancies may help in scheduling biopsies or avoiding unnecessary ones. However, there have been few studies on determining these factors. We aimed to determine the factors associated with the final diagnosis in cases requiring spinal biopsy. This study included 117 patients who underwent image-guided (fluoroscopy- or computed tomography [CT]-guided) needle biopsy of the spine. Data on patient demographic, pathological diagnoses, and final diagnoses were retrospectively collected from the medical records. The imaging features and location of lesions were also evaluated on CT and magnetic resonance imaging. Furthermore, factors related to tumors or malignancies were analyzed. The diagnostic accuracy of biopsy was 94.0%, and there was no difference in the diagnostic accuracy between the fluoroscopic and CT-guided biopsies. Sixty-six and fifty-six patients were diagnosed with spinal tumors and malignant tumors, respectively. Multivariate analysis revealed that a history of malignant tumors and the presence of pedicle lesions and/or extravertebral lesions were related factors for both tumors or malignancy in the final diagnosis. These findings can help determine the necessity for or timing of biopsy in patients with suspected spinal tumors.

Risk Factors for Poor Outcome after Palliative Surgery for Metastatic Spinal Tumors.

Palliative surgery is performed to improve the quality of life of patients with spinal metastases. However, it is sometimes difficult to achieve the expected results because the patient's condition, and risk factors related to poor outcomes have not been well elucidated. This study aimed to evaluate the functional outcomes and investigate the risk factors for poor outcomes after palliative surgery for spinal metastasis. We retrospectively reviewed the records of 117 consecutive patients who underwent palliative surgery for spinal metastases. Neurological and ambulatory statuses were evaluated pre- and post-operatively. Poor outcomes were defined as no improvement or deterioration in functional status or early mortality, and the related risk factors were analyzed using multivariate logistic regression analysis. The results showed neurological improvement in 48% and ambulatory improvement in 70% of the patients with preoperative impairment, whereas 18% of the patients showed poor outcomes. In the multivariate analysis, low hemoglobin levels and low revised Tokuhashi scores were identified as risk factors for poor outcomes. The present results suggest that anemia and low revised Tokuhashi scores are related not only to life expectancy but also to functional recovery after surgery. Treatment options should be carefully selected for the patients with these factors.

Deep Learning Algorithm for Identifying Cervical Cord Compression Due to Degenerative Canal Stenosis on Radiography.

STUDY DESIGN: Cross-sectional study. OBJECTIVE: Validate the diagnostic accuracy of a deep-learning algorithm for cervical cord compression due to degenerative canal stenosis on radiography. SUMMARY OF BACKGROUND DATA: The diagnosis of degenerative cervical myelopathy is often delayed, resulting in improper management. Screening tools for suspected degenerative cervical myelopathy would help identify patients who require detailed physical evaluation. MATERIALS AND METHODS: Data from 240 patients (120 with cervical stenosis on magnetic resonance imaging and 120 age and sex-matched controls) were randomly divided into training (n = 198) and test (n = 42) data sets. The deep-learning algorithm, designed to identify the suspected stenosis level on radiography, was constructed using a convolutional neural network model called EfficientNetB2, and radiography and magnetic resonance imaging data from the training data set. The accuracy and area under the curve of the receiver operating characteristic curve were calculated for the independent test data set. Finally, the number of correct diagnoses was compared between the algorithm and 10 physicians using the test cohort. RESULTS: The diagnostic accuracy and area under the curve of the deep-learning algorithm were 0.81 and 0.81, respectively, in the independent test data set. The rate of correct responses in the test data set was significantly higher for the algorithm than for the physician's consensus (81.0% vs . 66.2%; P = 0.034). Furthermore, the accuracy of the algorithm was greater than that of each individual physician. CONCLUSIONS: We developed a deep-learning algorithm capable of suggesting the presence of cervical spinal cord compression on cervical radiography and highlighting the suspected levels on radiographic imaging when cord compression is identified. The diagnostic accuracy of the algorithm was greater than that of spine physicians. LEVEL OF EVIDENCE: Level IV.

A decision tree analysis to predict clinical outcome of minimally invasive lumbar decompression surgery for lumbar spinal stenosis with and without coexisting spondylolisthesis and scoliosis.

BACKGROUND CONTEXT: Implementing machine learning techniques, such as decision trees, known as prediction models that use logical construction diagrams, are rarely used to predict clinical outcomes. PURPOSE: To develop a clinical prediction rule to predict clinical outcomes in patients who undergo minimally invasive lumbar decompression surgery for lumbar spinal stenosis with and without coexisting spondylolisthesis and scoliosis using a decision tree model. STUDY DESIGN/SETTING: A retrospective analysis of prospectively collected data. PATIENT SAMPLE: This study included 331 patients who underwent minimally invasive surgery for lumbar spinal stenosis and were followed up for ≥2 years at 1 institution. OUTCOME MEASURES: Self-report measures: The Japanese Orthopedic Association (JOA) scores and low back pain (LBP)/leg pain/leg numbness visual analog scale (VAS) scores. Physiologic measures: Standing sagittal spinopelvic alignment, computed tomography, and magnetic resonance imaging results. METHODS: Low achievement in clinical outcomes were defined as the postoperative JOA score at the 2-year follow-up <25 points. Univariate and multiple logistic regression analysis and chi-square automatic interaction detection (CHAID) were used for analysis. RESULTS: The CHAID model for JOA score <25 points showed spontaneous numbness/pain as the first decision node. For the presence of spontaneous numbness/pain, sagittal vertical axis ≥70 mm was selected as the second decision node. Then lateral wedging, ≥6° and pelvic incidence minus lumbar lordosis (PI-LL) ≥30° followed as the third decision node. For the absence of spontaneous numbness/pain, sex and lateral olisthesis, ≥3mm and American Society of Anesthesiologists physical status classification system score were selected as the second and third decision nodes. The sensitivity, specificity, and the positive predictive value of this CHAID model was 65.1, 69.8, and 64.7% respectively. CONCLUSIONS: The CHAID model incorporating basic information and functional and radiologic factors is useful for predicting surgical outcomes.

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.

Change in Physical and Mental Quality-of-Life between the Short- and Mid-Term Periods after Cervical Laminoplasty for Cervical Spondylotic Myelopathy: A Retrospective Cohort Study with Minimum 5 Years Follow-up.

The mid-term surgical outcomes of cervical spondylotic myelopathy (CSM), evaluated using the cervical Japanese Orthopedic Association (cJOA) score, are reported to be satisfactory. However, there remains room for improvement in quality-of-life (QOL), especially after short-term follow-up. We aimed to demonstrate changes in mental and physical QOL between short- and mid-term follow-ups and determine the predictive factors for deterioration of QOL. In this retrospective cohort study, 80 consecutive patients underwent laminoplasty for CSM. The outcome measures were Short Form-36 Physical Component Summary (PCS), Mental Component Summary (MCS), and cJOA scores. PCS and MCS scores were compared at the 2- and 5-year postoperative time points. Additionally, a multivariate logistic regression model was used to identify the predictive factors for deterioration. Significant factors in the logistic regression analysis were analyzed using receiver-operating characteristic curves. The results showed that MCS scores did not deteriorate after 2 years postoperatively (p = 0.912). Meanwhile, PCS significantly declined between 2 and 5 years postoperatively (p = 0.008). cJOA scores at 2 years postoperatively were significantly associated with PCS deterioration at 2-year follow-up. In conclusion, only physical QOL might show deterioration after short-term follow-up. Such deterioration is likely in patients with a cJOA score <13.0 at 2 years postoperatively.

Age-related morphological and functional changes in the small intestine of senescence-accelerated mouse.

The ability of the small intestine to perform various functions, such as digestion/absorption of nutrients, gradually declines with age. However, the mechanism that causes intestinal senescence remains unclear. Therefore, age-related changes in the jejunum and ileum were evaluated using senescence-accelerated mouse (SAM) strains that possess characteristic phenotypes of aging. In particular, to understand how senescence affects the small intestine, we investigated whether age-related changes in the morphology of the intestinal villi and its capability to digest/absorb nutrients are associated with the senescence phenotypes identified in specific SAM strains. Four SAM strains were selected (SAMP1, SAMP6, SAMP10, and SAMR1; of which SAMR1 served as a control of SAMP strain) and age-related changes in the small intestine were evaluated for each strain. A villus morphological analysis, mRNA expression level analysis of the small intestine-specific molecules, and disaccharidase activity measurement were performed. We observed that the mRNA expression levels of the genes involved in the differentiation of intestinal epithelial cells and in the digestion/absorption of nutrients were markedly decreased in all the SAM strains, especially in the SAMP10 strain. Our results revealed that all the SAM strains spontaneously induced senescence of the small intestine, which occurred due to the disorders affecting the differentiation/maturation system of intestinal epithelial cells. In addition, it was evident that senile phenotypes, such as brain dysfunction, enhanced intestinal senescence in the SAMP10 strain. The results of this study suggest that the brain-intestinal nervous system may play role in maintenance of villous morphology and nutrients uptake via the GLP-2 and IGF-2 signaling pathway.

Direct Lateral Corpectomy and Reconstruction Using an Expandable Cage Improves Local Kyphosis but Not Global Sagittal Alignment.

Recently, an expandable cage equipped with rectangular footplates has been used for anterior vertebral replacement in osteoporotic vertebral fracture (OVF). However, the postoperative changes in global alignment have not been elucidated. The purpose of this study was to evaluate local and global spinal alignment after anterior and posterior spinal fixation (APSF) using an expandable cage in elderly OVF patients. This retrospective multicenter review assessed 54 consecutive patients who underwent APSF for OVF. Clinical outcomes were compared between postoperative sagittal vertical axis (SVA) > 95 mm and ≤95 mm groups to investigate the impact of malalignment. SVA improved by only 18.7 mm (from 111.8 mm to 93.1 mm). VAS score of back pain at final follow-up was significantly higher in patients with SVA > 95 mm than SVA ≤ 95 mm (42.4 vs. 22.6, p = 0.007). Adjacent vertebral fracture after surgery was significantly more frequent in the SVA > 95 mm (37% vs. 11%, p = 0.038). Multiple logistic regression showed significantly increased OR for developing adjacent vertebral fracture (OR = 4.76, 95% CI 1.10-20.58). APSF using the newly developed cage improves local kyphotic angle but not SVA. The main cause for the spinal malalignment after surgery was postoperative development of adjacent vertebral fractures.

Spontaneous Improvement of Postoperative Coronal Imbalance Following Selective Thoracolumbar-Lumbar Fusion in Lenke 5C Adolescent Idiopathic Scoliosis.

OBJECTIVE: To evaluate prevalence and prognosis of postoperative coronal imbalance (CIB) and factors related to its onset and spontaneous improvement in patients with Lenke 5C adolescent idiopathic scoliosis who underwent selective thoracolumbar-lumbar fusion. METHODS: We measured radiographic parameters and evaluated clinical outcomes using the Scoliosis Research Society-22 questionnaire in patients with Lenke 5C adolescent idiopathic scoliosis and a minimum 2-year follow-up. CIB was defined as >2 cm distance between C7 plumb line and central sacral vertical line. We compared parameters between patients with CIB (CIB group) and without CIB (coronal balanced group). RESULTS: Inclusion criteria were met by 29 patients (mean age at surgery:17.0 years; average follow-up period: 45.6 months). CIB was found in 10 patients 1 week after surgery (34.5%); this decreased to 6.9% at final follow-up. Comparative analysis indicated significant values as follows: age at surgery (17.5 years vs. 14.7 years, P = 0.005), lumbosacral curve (5.9° vs. 11.2°, P = 0.02), and L5 tilt (-3.6° vs. -8.1°, P = 0.02) in bending film. Greater changes of lowest instrumented vertebra disc angle, which means scoliotic angles between LIV and LIV+1, were significantly associated with spontaneous improvement of CIB (P = 0.04). Clinical outcomes were comparable between the coronal balanced and CIB groups. CONCLUSIONS: Although CIB was frequently detected in the early postoperative period after selective thoracolumbar-lumbar fusion, it mostly corrected spontaneously. Relatively younger age at surgery and less flexible lumbosacral curve may be related to postoperative CIB, and greater changes of LIV disc angle may be associated with spontaneous improvement of CIB.

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.

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.

Comparative Study of the Spinopelvic Alignment in Patients With Idiopathic Lumbar Scoliosis Between Adulthood and Adolescence.

BACKGROUND: Understanding the natural history of the spinopelvic alignment in adolescent idiopathic scoliosis (AIS) is important in developing surgical strategies for patients with adult idiopathic lumbar scoliosis (AdLS). Because it is challenging to follow individuals without any treatments, we sought to estimate its natural history by comparing radiographic characteristics of patients with AIS and AdLS. METHODS: We included patients with Lenke 5 AIS and patients with AdLS who were diagnosed with Lenke 5 AIS in adolescence. The Cobb angle of the curve and spinopelvic parameters were measured by whole spine radiographs. The AdLS patients were divided into 2 groups according to age <50 years (AdLS<50) or ≥50 years (AdLS≥50). Radiographic parameters were compared among the AIS, AdLS<50, and AdLS≥50 groups. The relationship between age and each parameter was analyzed using nonlinear regression analysis. RESULTS: We analyzed 40 patients with AIS (all female, mean age 16.8 ± 3.2 years) and 35 patients with AdLS (34 female and 1 male, mean age 55.4 ± 12.1 years). Thoracolumbar/lumbar curve and thoracolumbar kyphosis was significantly greater in the AdLS<50 group compared with the AIS group, without progression after age 50 years. Lumbar lordosis and pelvic tilt deteriorated linearly with age. AIS and AdLS<50 patients maintained sagittal balance, which deteriorated in AdLS≥50 patients. CONCLUSIONS: Our results may predict the following natural course of Lenke 5 AIS: (1) progression of scoliotic deformity of thoracolumbar/lumbar curve with increased thoracolumbar kyphosis; (2) subsequent lumbar hypolordosis followed by pelvic retroversion; and (3) sagittal imbalance after failure of compensation.

Differences in surgical outcome after anterior corpectomy and reconstruction with an expandable cage with rectangular footplates between thoracolumbar and lumbar osteoporotic vertebral fracture.

BACKGROUND: Anterior and posterior spinal fixation (APSF) can provide rigid structural anterior column support in patients with osteoporotic vertebral fracture (OVF). A new rectangular footplate designed based on biomechanical studies of endplates provides better resistance to subsidence. However, differences in characteristics exist between the thoracolumbar and lower lumbar spine. The purpose of this study was to evaluate the surgical outcomes following APSF using an expandable cage with rectangular footplates in the thoracolumbar/lumbar region. METHODS: Consecutive patients who underwent APSF for OVF at multiple centers were retrospectively reviewed. Clinical and radiographic evaluations were performed by dividing the patients into thoracolumbar (TL, T10-L2) and lumbar (L, L3-L5) groups. Surgical indications were incomplete neurologic deficit or intractable back pain with segmental spinal instability. Surgical outcomes including the Japanese Orthopaedic Association (JOA) score and reoperation rate were compared between TL and L groups. RESULTS: Sixty-nine patients were followed-up for more than 12 months and analyzed. Operative intervention was required for 35 patients in the TL group and 34 patients in the L group. Mean ages in the TL and L groups were 76.5 years and 75.1 years, respectively. Intra-vertebral instability was more frequent in the TL group (p<0.001). Screw fixation range was significantly longer in the TL group (p=0.012). The rate of cage subsidence did not differ significantly between the TL group (46%) and L group (44%). Reoperation rate tended to be higher in the TL group (p=0.095). Improvement ratio of JOA score was significantly better in the L group (60%) than in the TL group (46.9%, p=0.029). CONCLUSION: APSF using an expandable cage was effective to treat OVF at both lumbar and thoracolumbar levels. However, the improvement ratio of the JOA score was better in the L group than in the TL group.