Biomechanical investigation of long spinal fusion models using three-dimensional finite element analysis.

BACKGROUND: This study represents the first finite element (FE) analysis of long-instrumented spinal fusion from the thoracic vertebrae to the pelvis in the context of adult spinal deformity (ASD) with osteoporosis. We aimed to evaluate the von Mises stress in long spinal instrumentation for models that differ in terms of spinal balance, fusion length, and implant type. METHODS: In this three-dimensional FE analysis, FE models were developed based on computed tomography images from a patient with osteoporosis. The von Mises stress was compared for three different sagittal vertical axes (SVAs) (0, 50, and 100 mm), two different fusion lengths (from the pelvis to the second [T2-S2AI] or 10th thoracic vertebra [T10-S2AI]), and two different types of implants (pedicle screw or transverse hook) in the upper instrumented vertebra (UIV). We created 12 models based on combinations of these conditions. RESULTS: The overall von Mises stress was 3.1 times higher on the vertebrae and 3.9 times higher on implants for the 50-mm SVA models than that for the 0-mm SVA models. Similarly, the values were 5.0 times higher on the vertebrae and 6.9 times higher on implants for the 100-mm SVA models than that for the 0-mm SVA models. Higher SVA was associated with greater stress below the fourth lumbar vertebrae and implants. In the T2-S2AI models, the peaks of vertebral stress were observed at the UIV, at the apex of kyphosis, and below the lower lumbar spine. In the T10-S2AI models, the peaks of stress were observed at the UIV and below the lower lumbar region. The von Mises stress in the UIV was also higher for the screw models than for the hook models. CONCLUSION: Higher SVA is associated with greater von Mises stress on the vertebrae and implants. The stress on the UIV is greater for the T10-S2AI models than for the T2-S2AI models. Using transverse hooks instead of screws at the UIV may reduce stress in patients with osteoporosis.

Tumor-Specific Immunoenhancing Effects after Local Cryoablation for Metastatic Bone Tumor in a Mouse Model.

We investigated the abscopal effect after cryoablation (CA) on bone metastasis using a mouse model. Breast cancer cells were implanted in the bilateral tibiae of mice. The left tumor was treated locally with CA, and the right abscopal tumor (AT) was left untreated. The mice were divided into four groups based on the combination of CA and intraperitoneal administration of anti-PD-1 antibody (PD) as treatment interventions (Control, CA, PD, and CA + PD). The reduction ratio of the size of AT, the quantitative immune effects at enzyme-linked immunospot (ELISPOT) assay, and the intensity of infiltration of immune-related cells to AT were compared among the groups. CA alone showed a significant immunoenhancing effect on the volume change ratio of AT from day 0 to day 14 (Control-CA: p < 0.05), ELISPOT assay (Control-CA: p < 0.01), and CD4+ cell count in immunostaining (Control-CA: p < 0.05). CA alone showed no significant immunoenhancing effect on CD8+ and Foxp3+ cell counts in immunostaining, but the combination of CA and PD showed a significant immunoenhancing effect (Control-CA + PD: p < 0.01 [CD8, Foxp3]). The results suggested that the abscopal effect associated with the local cryotherapy of metastatic bone tumors was activated by CA and enhanced by its combination with PD.

Prevalence and Risk Factors for the Development of Venous Thromboembolism After Spinal Tumor Surgery.

OBJECTIVE: Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary thromboembolism (PTE), is a deleterious complication that can be fatal. However, the prevalence and underlying risk factors for VTE after spinal tumor surgery remain poorly defined. METHODS: Ninety-six patients undergoing spinal tumor surgery with postoperative screening for DVT and PTE were reviewed. We evaluated the relationship between postoperative VTE and the following factors: age, sex, height, weight, body mass index, location of the tumor, type of tumor (primary or metastasis), type of operation (excisional surgery or palliative surgery), surgical approach (posterior or combined), operative time, intraoperative blood loss, perioperative transfusion, amount of transfusion, duration of postoperative bed rest (<7 days or >7 days), preoperative paralysis, postoperative paralysis, and postoperative neurological worsening. RESULTS: The overall prevalence of VTE was 25.0% (24/96). The rate of DVT and PTE was 20.8% (20/96) and 6.3% (6/96), respectively. PTE only was identified in 4 of 6 PTE-positive patients, and both PTE and DVT were identified in 2. In univariate analysis, the duration of postoperative bed rest of the VTE group was significantly longer than that of the non-VTE group (P = 0.03). In multivariate analysis, only prolonged duration of postoperative bed rest was a significant independent risk factor (P = 0.036). CONCLUSIONS: The prevalence of VTE after spinal tumor surgery was 25.0%. Prolonged duration of postoperative bed rest was a risk factor for postoperative VTE. No DVT was found in 4 of 6 PTE-positive patients, suggesting that screening for PTE itself is also needed in high-risk cases of VTE.

Revision balloon kyphoplasty and vertebra-pediculoplasty using cannulated screws for osteoporotic vertebral fractures with cement dislodgement following conventional balloon kyphoplasty.

We report the usefulness of revision balloon kyphoplasty (re-BKP) and vertebra-pediculoplasty using cannulated screws (VPCS) for osteoporotic vertebral fractures (OVF) following cement dislodgement of conventional BKP. Between 2015 and 2020, three patients with OVF developed symptomatic cement dislodgement following BKP and underwent re-BKP. All three patients showed a loose cemented mass and spinal instability. Balloon inflation was performed in the gap between the loosened cemented mass and the remaining cortical bone rim, and this extended gap was filled with cement. To prevent re-dislodgement of the cement mass, a cannulated screw was inserted into the cemented mass through the pedicle. All patients achieved early pain relief, and improved vertebral stability of the fractured vertebra and all related symptoms, with no perioperative complications. Re-BKP and VPCS are innovative concepts and could be an effective minimally invasive treatment for OVF following cement dislodgement of conventional BKP treatment.

Effects of Radiation on the Bone Strength of Spinal Vertebrae in Rats.

STUDY DESIGN: A controlled laboratory study. OBJECTIVE: The aim of this study was to examine bone damage caused by irradiation to spinal vertebrae in rats. SUMMARY OF BACKGROUND DATA: Radiotherapy is widely used in the treatment of malignant spine tumors. However, a few studies have reported vertebral fractures following radiotherapy as an adverse reaction. There are no reports on irradiation- induced changes in bone fragility, mechanical and structural changes focusing on the spine, and the mechanism of irradiation-induced bone osteoporosis. METHODS: Eighty-four female Wistar rats were randomly allocated to the 20 Gy irradiated or the nonirradiated (control) group. The lumbar vertebrae were irradiated with an external focal radiation dose of 20 Gy. Biomechanical, structural, and histological analyses were performed at 0, 2, 4, 6, 8, 12, and 24 weeks after irradiation. Structural analysis and bone density measurement of vertebral trabecular bone were performed by µCT. Histopathological evaluation was performed by hematoxylin and eosin staining and immunostaining. RESULTS: The bone strength at 2 weeks after irradiation (311 ±â€Š23 N) was 22% lower than that before irradiation (398 ±â€Š34 N) (P  < 0.05). The trabecular spacing increased, and trabecular connectivity and width decreased significantly in the irradiated group compared with those in the non-irradiated group. The three-dimensional structure model became coarse, and the trabecular structure continued to thin and disrupt after irradiation. There was no significant change in the bone mineral density in both groups. CONCLUSION: A decrease in bone strength was observed 2 weeks after irradiation. Bone mineral density remained unaltered, whereas the microstructure of trabecular bone changed, suggesting bone damage by irradiation.Level of Evidence: N/A.

Validation and comparison of trunk muscle activities in male participants during exercise using an innovative device and abdominal bracing maneuvers.

BACKGROUND: Abdominal bracing is effective in strengthening the trunk muscles; however, assessing performance can be challenging. We created a device for performing abdominal trunk muscle exercises. The effectiveness of this device has not yet been evaluated or comparedOBJECTIVE: We aimed to quantify muscle activity levels during exercise using our innovative device and to compare them with muscle activation during abdominal bracing maneuvers. METHODS: This study included 10 men who performed abdominal bracing exercises and exercises using our device. We measured surface electromyogram (EMG) activities of the rectus abdominis (RA), external oblique, internal oblique (IO), and erector spinae (ES) muscles in each of the exercises. The EMG data were normalized to those recorded during maximal voluntary contraction (%EMGmax). RESULTS: During the bracing exercise, the %EMGmax of IO was significantly higher than that of RA and ES (p< 0.05), whereas during the exercises using the device, the %EMGmax of IO was significantly higher than that of ES (p< 0.05). No significant difference was observed in the %EMGmax of any muscle between bracing exercises and the exercises using the device (p= 0.13-0.95). CONCLUSIONS: The use of our innovative device results in comparable activation to that observed during abdominal bracing.

Vertebra-Pediculoplasty: A New Approach to Treatment of Split-Type and Delayed-Union Osteoporotic Vertebral Fracture with a Risk of Cement Dislodgement.

BACKGROUND: The clinical outcomes of balloon kyphoplasty (BKP) for split-type osteoporotic vertebral fractures (OVF) are poor. These may be owing to the vertebral body bifurcating anteriorly and posteriorly when a load is applied and the filled cement being unstable. We report the usefulness of BKP combined with pediculoplasty using cannulated screws (vertebra-pediculoplasty) for OVF with a risk of cement dislodgement. METHODS: Between April 2020 and February 2021, this surgery was performed on 10 patients with split-type and delayed-union OVF. The diagnosis was made using imaging findings on preoperative computed tomography or intraoperative images during balloon inflation. Early postoperative ambulatory rehabilitation was performed, and clinical outcomes were evaluated. RESULTS: Early pain relief was obtained in all patients. The stability of the fractured vertebrae was demonstrated using both supine and seated radiographs from the early postoperative period, and good clinical results were obtained. The cement in this surgery was stabilized using a cannulated screw in the vertebral body, anteroposteriorly, and craniocaudally. The cement mass integrated with the cannulated screw was stabilized with the vertebral lamina and pedicle as a stopper. CONCLUSIONS: Vertebra-pediculoplasty could be an effective method for managing OVF with a high risk of cement dislodgement, which has been difficult to treat using conventional BKP.

Abscopal Effect of Frozen Autograft Reconstruction Combined with an Immune Checkpoint Inhibitor Analyzed Using a Metastatic Bone Tumor Model.

We evaluated the abscopal effect of re-implantation of liquid nitrogen-treated tumor-bearing bone grafts and the synergistic effect of anti-PD-1 (programmed death-1) therapy using a bone metastasis model, created by injecting MMT-060562 cells into the bilateral tibiae of 6-8-week-old female C3H mice. After 2 weeks, the lateral tumors were treated by excision, cryotreatment using liquid nitrogen, excision with anti-PD-1 treatment, and cryotreatment with anti-PD-1 treatment. Anti-mouse PD-1 4H2 was injected on days 1, 6, 12, and 18 post-treatment. The mice were euthanized after 3 weeks; the abscopal effect was evaluated by focusing on growth inhibition of the abscopal tumor. The re-implantation of frozen autografts significantly inhibited the growth of the remaining abscopal tumors. However, a more potent abscopal effect was observed in the anti-PD-1 antibody group. The number of CD8+ T cells infiltrating the abscopal tumor and tumor-specific interferon-γ (IFN-γ)-producing spleen cells increased in the liquid nitrogen-treated group compared with those in the excision group, with no significant difference. The number was significantly higher in the anti-PD-1 antibody-treated group than in the non-treated group. Overall, re-implantation of tumor-bearing frozen autograft has an abscopal effect on abscopal tumor growth, although re-implantation of liquid nitrogen-treated bone grafts did not induce a strong T-cell response or tumor-suppressive effect.

Simultaneous-onset infectious spondylitis with vertebral fracture mimicking an acute osteoporotic vertebral fracture erroneously treated with balloon kyphoplasty: illustrative case.

BACKGROUND: Early balloon kyphoplasty (BKP) intervention for acute osteoporotic vertebral fracture (OVF) has been reported to be more effective than the conservative treatment. However, complications of early BKP intervention are still unknown. OBSERVATIONS: A 71-year-old patient with OVF of L2 underwent BKP 2 weeks after symptom onset. Preoperative magnetic resonance imaging (MRI) and radiograph were compatible with new L2 OVF. Although computed tomography (CT) images revealed the atypical destruction of lower endplate of L2 as OVF, L2 BKP was planned. After BKP, his back pain improved dramatically. Two weeks after BKP, his lower back pain recurred. MRI and CT confirmed the diagnosis of infectious spondylitis with paravertebral abscess formation. With adequate antibiotic treatment and rehabilitation, he was symptom-free and completely ambulatory without signs of infection. LESSONS: Signal changes on the fractured vertebral bodies during initial MRI and fractured vertebral instability on radiograph can mislead the surgeon to interpret the infection as a benign compression fracture. If the patients exhibit unusual destruction of the endplate on CT imaging, "simultaneous-onset" spondylitis with vertebral fracture should be included in the differential diagnosis. To determine the strategy for OVF, preoperative biopsy is recommended if simultaneous-onset spondylitis with vertebral fracture is suspected.

Radiation Disrupts the Protective Function of the Spinal Meninges in a Mouse Model of Tumor-induced Spinal Cord Compression.

BACKGROUND: Recent advances in multidisciplinary treatments for various cancers have extended the survival period of patients with spinal metastases. Radiotherapy has been widely used to treat spinal metastases; nevertheless, long-term survivors sometimes undergo more surgical intervention after radiotherapy because of local tumor relapse. Generally, intradural invasion of a spinal tumor seldom occurs because the dura mater serves as a tissue barrier against tumor infiltration. However, after radiation exposure, some spinal tumors invade the dura mater, resulting in leptomeningeal dissemination, intraoperative dural injury, or postoperative local recurrence. The mechanisms of how radiation might affect the dura have not been well-studied. QUESTIONS/PURPOSES: To investigate how radiation affects the spinal meninges, we asked: (1) What is the effect of irradiation on the meningeal barrier's ability to protect against carcinoma infiltration? (2) What is the effect of irradiation on the meningeal barrier's ability to protect against sarcoma infiltration? (3) What is the effect of irradiation on dural microstructure observed by scanning electron microscopy (SEM)? (4) What is the effect of irradiation on dural microstructure observed by transmission electron microscopy (TEM)? METHODS: Eighty-four 10-week-old female ddY mice were randomly divided into eight groups: mouse mammary tumor (MMT) implantation 6 weeks after 0-Gy irradiation (nonirradiation) (n = 11), MMT implantation 6 weeks after 20-Gy irradiation (n = 10), MMT implantation 12 weeks after nonirradiation (n = 10), MMT implantation 12 weeks after 20-Gy irradiation (n = 11), mouse osteosarcoma (LM8) implantation 6 weeks after nonirradiation (n = 11), LM8 implantation 6 weeks after 20-Gy irradiation (n = 11), LM8 implantation 12 weeks after nonirradiation (n = 10), and LM8 implantation 12 weeks after 20-Gy irradiation (n = 10); female mice were used for a mammary tumor metastasis model and ddY mice, a closed-colony mice with genetic diversity, were selected to represent interhuman diversity. Mice in each group underwent surgery to generate a tumor-induced spinal cord compression model at either 6 weeks or 12 weeks after irradiation to assess changes in the meningeal barrier's ability to protect against tumor infiltration. During surgery, the mice were implanted with MMT (representative of a carcinoma) or LM8 tumor. When the mice became paraplegic because of spinal cord compression by the growing implanted tumor, they were euthanized and evaluated histologically. Four mice died from anesthesia and 10 mice per group were euthanized (MMT-implanted groups: MMT implantation occurred 6 weeks after nonirradiation [n = 10], 6 weeks after irradiation [n = 10], 12 weeks after nonirradiation [n = 10], and 12 weeks after irradiation [n = 10]; LM8-implanted groups: LM8 implantation performed 6 weeks after nonirradiation [n = 10], 6 weeks after irradiation [n = 10], 12 weeks after nonirradiation [n = 10], and 12 weeks after irradiation [n = 10]); 80 mice were evaluated. The spines of the euthanized mice were harvested; hematoxylin and eosin staining and Masson's trichrome staining slides were prepared for histologic assessment of each specimen. In the histologic assessment, intradural invasion of the implanted tumor was graded in each group by three observers blinded to the type of tumor, presence of irradiation, and the timing of the surgery. Grade 0 was defined as no intradural invasion with intact dura mater, Grade 1 was defined as intradural invasion with linear dural continuity, and Grade 2 was defined as intradural invasion with disruption of the dural continuity. Additionally, we euthanized 12 mice for a microstructural analysis of dura mater changes by two observers blinded to the presence of irradiation. Six mice (three mice in the 12 weeks after nonirradiation group and three mice in the 12 weeks after 20-Gy irradiation group) were quantitatively analyzed for defects on the dural surface with SEM. The other six mice (three mice in the 12 weeks after nonirradiation group and three mice in the 12 weeks after 20-Gy irradiation group) were analyzed for layer structure of collagen fibers constituting dura mater by TEM. In the SEM assessment, the number and size of defects on the dural surface on images (200 µm × 300 µm) at low magnification (× 2680) were evaluated. A total of 12 images (two per mouse) were evaluated for this assessment. The days from surgery to paraplegia were compared between each of the tumor groups using the Kruskal-Wallis test. The scores of intradural tumor invasion grades and the number of defects on dural surface per SEM image were compared between irradiation group and nonirradiation group using the Mann-Whitney U test. Interobserver reliabilities of assessing intradural tumor invasion grades and the number of dural defects on the dural surface were analyzed using Fleiss'κ coefficient. P values < 0.05 were considered statistically significant. RESULTS: There was no difference in the median (range) time to paraplegia among the MMT implantation 6 weeks after nonirradiation group, the 6 weeks after irradiation group, the 12 weeks after nonirradiation group, and the 12 weeks after irradiation group (16 days [14 to 17] versus 14 days [12 to 18] versus 16 days [14 to 17] versus 14 days [12 to 15]; χ2 = 4.7; p = 0.19). There was also no difference in the intradural invasion score between the MMT implantation 6 weeks after irradiation group and the 6 weeks after nonirradiation group (8 of 10 Grade 0 and 2 of 10 Grade 1 versus 10 of 10 Grade 0; p = 0.17). On the other hand, there was a higher intradural invasion score in the MMT implantation 12 weeks after irradiation group than the 12 weeks after nonirradiation group (5 of 10 Grade 0, 3 of 10 Grade 1 and 2 of 10 Grade 2 versus 10 of 10 Grade 0; p = 0.02). Interobserver reliability of assessing intradural tumor invasion grades in the MMT-implanted group was 0.94. There was no difference in the median (range) time to paraplegia among in the LM8 implantation 6 weeks after nonirradiation group, the 6 weeks after irradiation group, the 12 weeks after nonirradiation group, and the 12 weeks after irradiation group (12 days [9 to 13] versus 10 days [8 to 13] versus 11 days [8 to 13] versus 9 days [6 to 12]; χ2 = 2.4; p = 0.50). There was also no difference in the intradural invasion score between the LM8 implantation 6 weeks after irradiation group and the 6 weeks after nonirradiation group (7 of 10 Grade 0, 1 of 10 Grade 1 and 2 of 10 Grade 2 versus 8 of 10 Grade 0 and 2 of 10 Grade 1; p = 0.51), whereas there was a higher intradural invasion score in the LM8 implantation 12 weeks after irradiation group than the 12 weeks after nonirradiation group (3 of 10 Grade 0, 3 of 10 Grade 1 and 4 of 10 Grade 2 versus 8 of 10 Grade 0 and 2 of 10 Grade 1; p = 0.04). Interobserver reliability of assessing intradural tumor invasion grades in the LM8-implanted group was 0.93. In the microstructural analysis of the dura mater using SEM, irradiated mice had small defects on the dural surface at low magnification and degeneration of collagen fibers at high magnification. The median (range) number of defects on the dural surface per image in the irradiated mice was larger than that of nonirradiated mice (2 [1 to 3] versus 0; difference of medians, 2/image; p = 0.002) and the median size of defects was 60 µm (30 to 80). Interobserver reliability of assessing number of defects on the dural surface was 1.00. TEM revealed that nonirradiated mice demonstrated well-organized, multilayer structures, while irradiated mice demonstrated irregularly layered structures at low magnification. At high magnification, well-ordered cross-sections of collagen fibers were observed in the nonirradiated mice. However, disordered alignment of collagen fibers was observed in irradiated mice. CONCLUSION: Intradural tumor invasion and disruptions of the dural microstructure were observed in the meninges of mice after irradiation, indicating radiation-induced disruption of the meningeal barrier. CLINICAL RELEVANCE: We conclude that in this form of delivery, radiation is associated with disruption of the dural meningeal barrier, indicating a need to consider methods to avoid or limit Postradiation tumor relapse and spinal cord compression when treating spinal metastases so that patients do not experience intradural tumor invasion. Surgeons should be aware of the potential for intradural tumor invasion when they perform post-irradiation spinal surgery to minimize the risks for intraoperative dural injury and spinal cord injury. Further research in patients with irradiated spinal metastases is necessary to confirm that the same findings are observed in humans and to seek irradiation methods that prevent or minimize the disruption of meningeal barrier function.

The efficacy of surgical treatment on locomotive syndrome and physical function in patients with lumbar spinal canal stenosis.

BACKGROUND: Locomotive syndrome is a condition of reduced mobility due to problems with locomotive organs. Although lumbar spinal canal stenosis is one of the major diseases constituting locomotive syndrome, only few studies have focused on the association between the two pathologies. We aimed to investigate the effect of surgery on lumbar spinal canal stenosis with respect to locomotive syndrome using various physical function tests, including locomotive syndrome risk tests, before and after surgery. METHODS: Clinical data of 101 consecutive patients (male = 46; female = 55; mean age, 69.3 years) who underwent surgery for lumbar spinal canal stenosis at our institute were prospectively collected. Results of physical function tests, including stand-up test, two-step test, and 25-Question Geriatric Locomotive Function Scale, and the sagittal vertical axis were evaluated before and 1 year after surgery. The association between several parameters and improvement of risk level in locomotive syndrome was evaluated. RESULTS: In the total assessment, 93.1% of cases were in stage 2 and 6.9% in stage 1 preoperatively, while 72.4% were in stage 2, 22.4% in stage 1, and 5.2% in stage 0 at 1 year postoperatively. Postoperative improvement in the total assessment was observed in 28.7% of cases. Several physical function tests and sagittal vertical axis showed significant improvement after surgery. On multiple logistic regression analysis, age >75 years (odds ratio = 10.9, confidence interval = 1.09-109) and postoperative sagittal vertical axis >40 mm (odds ratio = 17.8, confidence interval = 1.78-177) were significant risk factors associated with non-improvement in risk level of locomotive syndrome. CONCLUSIONS: Surgical treatment for lumbar spinal canal stenosis improved physical function, including locomotive syndrome. Risk factors associated with non-improvement of locomotive syndrome were later-stage elderly and postoperative sagittal balance impairment.

Efficacy of abdominal trunk muscles-strengthening exercise using an innovative device in treating chronic low back pain: a controlled clinical trial.

Exercise is the most common conservative intervention for chronic low back pain (CLBP). We have developed an innovative exercise device for the abdominal trunk muscles that also measures muscle strength in a sitting position. The device, which is easy for patients with CLBP to use, allows for lumbar stabilization exercise under pressure. This study aimed to examine the efficacy of abdominal trunk muscle strengthening using the device in improving CLBP. We conducted a two-group non-randomized controlled clinical trial. CLBP patients were allocated into two groups. The strengthening group underwent a 12-week exercise program that included abdominal trunk muscle strengthening using our device and stretching exercises, while the control group received a 12-week stretching exercise program. The outcome measures included the improvement of the abdominal trunk muscle strength measured by the device, pain intensity of CLBP, physical function, and quality of life (QOL). A total of 40 participants (20 in each group) were analyzed. The strengthening group showed better improvement in the abdominal trunk muscle strength, CLBP, physical function, and QOL than in the control group. In conclusion, the strengthening exercise using the device with easy stretching was effective in improving the strength of the abdominal trunk muscles, pain intensity of CLBP, physical function, and QOL.

Revision surgery for instrumentation failure after total en bloc spondylectomy: a retrospective case series.

BACKGROUND: There have been several reports of instrumentation failure after three-column resections such as total en bloc spondylectomy (TES) for spinal tumors; however, clinical outcomes of revision surgery for instrumentation failure after TES are seldom reported. Therefore, this study assessed the clinical outcomes of revision surgery for instrumentation failure after TES. METHODS: This study employed a retrospective case series in a single center and included 61 patients with spinal tumors who underwent TES between 2010 and 2015 and were followed up for > 2 years. Instrumentation failure rate, back pain, neurological deterioration, ambulatory status, operation time, blood loss, complications, bone fusion after revision surgery, and re-instrumentation failure were assessed. Data were collected on back pain, neurological deterioration, ambulatory status, and management for patients with instrumentation failure, and we documented radiological bone fusion and re-instrumentation failure in cases followed up for > 2 years after revision surgery. RESULTS: Of the 61 patients, 26 (42.6%) experienced instrumentation failure at an average of 32 (range, 11-92) months after TES. Of these, 23 underwent revision surgery. The average operation time and intraoperative blood loss were 204 min and 97 ml, respectively. Including the six patients who were unable to walk after instrumentation failure, all patients were able to walk after revision surgery. Perioperative complications of reoperation were surgical site infection (n = 2) and delayed wound healing (n = 1). At the final follow-up, bone fusion was observed in all patients. No re-instrumentation failure was recorded. CONCLUSION: Bone fusion was achieved by revision surgery using the posterior approach alone.

Improvement of locomotive syndrome with surgical treatment in patients with degenerative diseases in the lumbar spine and lower extremities: a prospective cohort study.

BACKGROUND: The epidemiology, risk factors, and prevention of locomotive syndrome (LS) have been reported. However, the number of clinical studies about the efficacy of LS treatment, including surgery, has been limited. This study aimed to evaluate LS and its improvement in patients undergoing surgeries for degenerative disease of the lumbar spine and lower extremities, and to discuss the effects of surgery on LS and the issues of LS assessment in these patients. METHODS: We enrolled 257 patients aged ≥60 years that underwent surgery for degenerative diseases of the lumbar spine and lower extremities and agreed to participate in the preoperative and 6- and 12-month postoperative LS examinations. According to the disease location, patients were divided into the lumbar (n = 81), hip (n = 106), knee (n = 43), and foot and ankle (n = 27) groups. Patients underwent LS risk tests, including the stand-up test, two-step test, and 25-Question Geriatric Locomotive Function Scale (GLFS-25) assessment. RESULTS: The preoperative prevalence of LS stage 2 was 95%. Only the hip group showed significant improvements in the stand-up test. The knee group showed the worst results in the stand-up and two-step tests at all time points. All four groups had significant improvements in GLFS-25 scores. Approximately 40% of all patients had improvement in their LS stage postoperatively. However, > 90% of the patients in the knee group had LS stage 2 postoperatively. CONCLUSION: Nearly all elderly patients requiring surgeries for degenerative diseases of the lumbar spine and lower extremities had advanced conditions (LS stage 2). Surgeries could be beneficial in alleviating LS. The LS stage 3 criteria should be established, and the use of the GLFS-25 assessment can be appropriate for advanced LS patients with severe musculoskeletal diseases requiring surgeries.

Long-Term Outcomes of Excision Surgery for Aggressive Vertebral Hemangiomas.

OBJECTIVE: We describe the clinical outcomes in patients with aggressive vertebral hemangiomas (AVHs) after total tumor excision and discuss the treatment options for AVHs. METHODS: A retrospective data review of 15 patients (6 men, 9 women) with AVHs who underwent total excision between 1996 and 2018 was performed. RESULTS: In total, 13 thoracic and 2 lumbar lesions were involved with 8 type A-D tumors and 7 type B-D tumors based on the Weinstein-Boriani-Biagini classification. All tumors showed low or low-iso signal intensity by T1-weighted magnetic resonance imaging. All patients received a combination of preoperative transarterial embolization and total tumor excision including the tumor margins. Eleven patients underwent total tumor excision as the initial surgery (total en bloc spondylectomy = 10 patients, piecemeal total tumor excision = 1 patient), and 4 underwent it as either a revision procedure 2 weeks after ineffective laminectomy or in the long-term follow-up (4-14 years) as a piecemeal total tumor excision. Intraoperative blood loss ranged from 150 to 3400 mL (mean, 1314 mL). None of the cases had a recurrence during the mean follow-up period of 128.4 ± 88.6 months. CONCLUSIONS: Low signal intensity on T1-weighted magnetic resonance imaging was observed in all the patients with AVHs. The long-term clinical results of the preoperative transarterial embolization and total tumor excision were satisfactory. The effect of decompressive incomplete tumor excision is temporary for AVHs, and repeated tumor excision may be necessary because of tumor recurrence in the long term. Reliable total tumor excision during the initial surgery is desirable.

Efficacy and Safety of Abdominal Trunk Muscle Strengthening Using an Innovative Device in Elderly Patients With Chronic Low Back Pain: A Pilot Study.

OBJECTIVE: To examine the efficacy and safety of an innovative, device-driven abdominal trunk muscle strengthening program, with the ability to measure muscle strength, to treat chronic low back pain (LBP) in elderly participants. METHODS: Seven women with non-specific chronic LBP, lasting at least 3 months, were enrolled and treated with the prescribed exercise regimen. Patients participated in a 12-week device-driven exercise program which included abdominal trunk muscle strengthening and 4 types of stretches for the trunk and lower extremities. Primary outcomes were adverse events associated with the exercise program, improvement in abdominal trunk muscle strength, as measured by the device, and improvement in the numerical rating scale (NRS) scores of LBP with the exercise. Secondary outcomes were improvement in the Roland-Morris Disability Questionnaire (RDQ) score and the results of the locomotive syndrome risk test, including the stand-up and two-step tests. RESULTS: There were no reports of increased back pain or new-onset abdominal pain or discomfort during or after the device-driven exercise program. The mean abdominal trunk muscle strength, NRS, RDQ scores, and the stand-up and two-step test scores were significantly improved at the end of the trial compared to baseline. CONCLUSION: No participants experienced adverse events during the 12-week strengthening program, which involved the use of our device and stretching, indicating the program was safe. Further, the program significantly improved various measures of LBP and physical function in elderly participants.

Clinical outcomes and survivals after total en bloc spondylectomy for metastatic leiomyosarcoma in the spine.

PURPOSE: Leiomyosarcoma (LMS) is generally resistant to radiation and chemotherapy. Our study aimed to examine the outcomes of total en bloc spondylectomy (TES) for spinal metastatic LMS and to analyze potential factors associated with survival. METHODS: This study included 10 consecutive patients who underwent TES for spinal metastatic LMS at our institute between 2005 and 2016 and were followed up at a minimum of 3 years after surgery. At the time of TES, all the 10 patients had solitary bone metastases in the spine. Seven patients had a lowered performance status (PS) with an eastern cooperative oncology group (ECOG) grade of 2 or 3 due to back pain or neurological symptoms. The cancer-specific survival (CSS) time from TES to death or last follow-up was the main endpoint. Potential factors associated with survival were evaluated using the Kaplan-Meier analysis and the log-rank test. RESULTS: Five patients underwent a single vertebral resection, and the other five patients underwent two or three consecutive vertebral resections. Three patients developed perioperative complications including pulmonary thromboembolism and pneumothorax. Nine patients improved or fairly maintained their PS with an ECOG grade of 1. The 1-, 3-, and 5-year CSS rates after TES were 90%, 70%, and 47%, respectively. Only postoperative disability (ECOG PS grade 3) was significantly associated with short-term survival after TES. CONCLUSIONS: The clinical outcomes of 10 patients who underwent TES for spinal metastatic LMS were favorable without severe complications. Postoperative disability was significantly associated with short-term survival after TES.

Perioperative Complications and Prognosis of Curative Surgical Resection for Spinal Metastases in Elderly Patients.

OBJECTIVE: The purpose of this study was to evaluate perioperative complications and prognosis associated with curative surgical resection, such as total en bloc spondylectomy, for spinal metastases in elderly patients. METHODS: We retrospectively reviewed 103 consecutive patients who underwent curative surgery between 2010 and 2017 and divided them into group 1 (n = 27, age <50 years), group 2 (n = 47, age ≥50 and <65 years), and group 3 (n = 29, age ≥65 years). Perioperative complication rate and overall survival (OS) after surgery was evaluated. RESULTS: A total of 129 perioperative complications were observed in 76 of 112 surgeries. Among the 3 groups, the total number of complications per person was the highest in group 3, although the difference was not statistically significant. The total number of serious complications per person was the highest in group 3, which was statistically significant. (0.23 vs. 0.51 vs. 0.90; P < 0.05). No significant difference in OS was observed between the groups. In group 3, a significant difference in OS was found between subgroups 1 (renal cell, thyroid, and breast cancer metastasis) and 2 (other primary tumors) (P < 0.01). In group 3, 24 patients (83%) either maintained or had regained their ambulatory capacity at the final follow-up. CONCLUSIONS: Elderly patients who underwent curative surgery had significantly more frequent serious postoperative complications than nonelderly patients. Even in patients with advanced age, curative surgical resection can provide favorable prognosis and local control, especially in those with spinal metastases of renal cell and thyroid cancer.