Instrumentation failure following pediatric spine deformity growth-sparing surgery using traditional growing rods or vertical expandable prosthetic titanium ribs.

BACKGROUND: Instrumentation failure (IF) is a major complication associated with growth-sparing surgery for pediatric spinal deformities; however, studies focusing on IF following each surgical procedure are lacking. We aimed to evaluate the incidence, timing, and rates of unplanned return to the operating room (UPROR) associated with IF following each surgical procedure in growth-sparing surgeries using traditional growing rods (TGRs) and vertical expandable prosthetic titanium ribs (VEPTRs). METHODS: We reviewed 1,139 surgical procedures documented in a Japanese multicenter database from 2015 to 2017. Of these, 544 TGR and 455 VEPTR procedures were included for evaluation on a per-surgery basis. IF was defined as the occurrence of an implant-related complication requiring revision surgery. RESULTS: The surgery-based incidences of IF requiring revision surgery in the TGR and VEPTR groups were 4.3% and 4.0%, respectively, with no significant intergroup difference. Remarkably, there was a negative correlation between IF incidence per surgical procedure and the number of lengthening surgeries in both groups. In addition, rod breakage in the TGR group and anchor-related complications in the VEPTR group tended to occur relatively early in the treatment course. The surgery-based rates of UPROR due to IF in the TGR and VEPTR groups were 2.0% and 1.5%, respectively, showing no statistically significant difference. CONCLUSIONS: We found that IF, such as anchor related-complications and rod breakage, occurs more frequently earlier in the course of lengthening surgeries. This finding may help in patient counseling and highlights the importance of close postoperative follow-up to detect IF and improve outcomes.

Ten-Year Clinical Outcomes of Endoscope-Assisted Minimally Invasive Surgical Decompression for Lumbar Spinal Stenosis with Degenerative Spondylolisthesis and Comparison with Conservative Treatment.

Introduction: This study aimed to evaluate the 10-year clinical outcomes of endoscope-assisted, minimally invasive surgical (MIS) decompression for lumbar spinal canal stenosis (LSS) with lumbar degenerative spondylolisthesis (DS) and to compare the radiographic changes in patients who underwent this procedure with those who underwent conservative therapy at 10-year follow-up. Methods: Between April 2007 and April 2010, 347 consecutive patients with DS and evidence of LSS underwent conservative treatment first from 2 to 4 weeks. The 114 patients who failed conservative treatment were then treated surgically by endoscope-assisted MIS decompression. Of them, 91 patients were followed for more than 10 years (group S), and 146 of the 233 patients treated conservatively were followed for more than 10 years (group C). Clinical outcomes of endoscope-assisted MIS decompression were assessed using the Short Form Health Survey-36 score (SF-36), the Roland Morris Disability Questionnaire (RDQ), and the neurological leg symptoms of the Japanese Orthopaedic Association Score (JOA score). Radiographic changes of the two groups were assessed by %slip, dynamic %slip, range of motion (ROM), and the height of the disc (DH) on plain radiographs. Results: Significant improvements in clinical outcomes on the SF-36, RDQ, and neurological leg symptoms of the JOA were observed. Radiographic assessment did not show significant differences in the assessed items between the two groups at baseline and after last treatment. Both groups had significantly decreased ROM and DH. Conclusions: The 10-year clinical outcomes of endoscope-assisted MIS decompression for DS were generally good. Furthermore, on radiographic comparison, the progress of spondylolisthesis after this procedure was virtually the same as in the natural course of the disease at 10-year follow-up.

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.

Incidence and causes of instrument-related complications after primary definitive fusion for pediatric spine deformity.

OBJECTIVE: Various complications have been reported in the treatment of pediatric spinal deformities. Among these, instrument-related complications could be critical concerns and risks of reoperation. This study aimed to identify the incidence and causes of complications after primary definitive fusion for pediatric spine deformities. METHODS: The authors retrospectively collected data from 14 institutions about patients who underwent primary definitive fusion between 2015 and 2017. There were 1490 eligible patients (1184 female and 306 male), with a mean age of 13.9 years. The incidence, causes, and reoperation rates were analyzed according to 4 etiologies of pediatric spine deformity (congenital, neuromuscular, syndromic, idiopathic). The complications were also categorized as screw-, hook-, or rod-related complications, implant loosening or backout, and junctional problems. RESULTS: The incidence of overall instrument-related complications was 5.6% (84 cases). Regarding etiology, the incidence rates were 4.3% (idiopathic), 6.8% (syndromic), 7.9% (congenital), and 10.4% (neuromuscular) (p < 0.05). The most common causes were pedicle screw malposition (60.7%), followed by implant backout or loosening (15.4%), junctional problems (13.1%), rod breakage (4.8%), and other complications (6.0%). Univariate analysis showed that etiology, type of deformity (kyphosis), surgical procedure, operation time, and estimated blood loss were significant factors. Multivariate analysis revealed that etiology (neuromuscular), surgical procedure (combined approach), and operation time (> 5 hours) remained as significant risk factors. Among all patients with instrument-related complications, 45% (38/84) required revision surgery. Of these cases, > 50% were related to pedicle screw malposition. Medial breach was the most common complication regardless of location, from upper thoracic to lumbar spine. CONCLUSIONS: Pedicle screw malposition was the primary cause of overall complications and subsequent reoperation. In addition to more precise screw insertion techniques, meticulous confirmation of pedicle screw placement, especially of medial breach, may reduce the overall instrument-related complications and revision rates.

The L-type Amino Acid Transporter (LAT1) Expression in Patients with Scoliosis.

Introduction: Amino acid transporters are transmembrane proteins that are known to mediate the transfer of amino acids. As one of the amino acid transporters, LAT1, which is encoded by Slc7a5, mediates the cellular uptake of the essential amino acids. Recently, most studies have focused on examining the relationship between LAT1 and skeletal formation in terms of development. However, little is known regarding the clinical features of LAT1 in the cartilage, which might result in the development of skeletal deformities such as scoliosis. Thus, the aim of this study was to investigate the expression of L-type amino acid transporter 1 (LAT1) and its solute carrier transporter 7a5 (Slc7a5) in patients with pediatric scoliosis and to compare with the relationship between LAT1 and Slc7a5 expression and their clinical features. Methods: We have prospectively recruited 56 patients who underwent corrective spinal fusion for scoliosis. The patients comprised 40 girls and 16 boys, with a mean age of 13.1 years at the time of surgery. There were 34 idiopathic scoliosis (IS) patients, whereas 22 were congenital scoliosis (CS) patients. During the surgery, an epiphyseal part of the spinous process at apical vertebra was harvested; then, LAT1 and Slc7a5 expressions in the cartilage were evaluated. Results: As per our findings, LAT1 expression was observed in the cartilage in 60.7% (34 out of 56) of the patients. LAT1 expression in IS patients was 76%, which were statistically higher compared to 36% in CS patients. When compared with LAT1 expression, no statistical difference was noted in terms of age, gender, body mass index (BMI), Cobb angle, and Risser grade. Meanwhile, the mean Slc7a5 expression in IS patients was determined to be significantly higher than that in CS patients. No significant correlation was observed between Slc7a5 expression and age, BMI, and Cobb angle. Conclusions: LAT1 and Slc7a5 expression in IS and CS patients showed significant differences. These expressions were found to be not correlated with age, stature, and severity of the deformity.

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.

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.

Association of low back pain with muscle weakness, decreased mobility function, and malnutrition in older women: A cross-sectional study.

BACKGROUND: Low back pain (LBP) and decreased mobility function are common problem among older people. Muscle weakness has been reported as a risk factor for these conditions, and exercise therapy can improve them. We created a novel exercise device that also measures abdominal trunk muscle strength. Malnutrition has also emerged as a major problem among older people. Muscle is a direct key linking decreased mobility function and malnutrition. This study aimed to examine the associations of LBP with not only decreased physical function and muscle weakness but also nutritional status of older people. METHODS: We examined the associations of LBP with muscle weakness, decreased mobility function (locomotive syndrome [LS]), and malnutrition among older women. The study included 101 female patients aged 60 years or older scheduled to undergo surgery for degenerative lower extremity diseases. Preoperatively, physical tests including abdominal trunk muscle strength assessment using the device and laboratory tests were conducted. Subjects with LBP (numerical rating scale ≥2; range, 0-4) during the preceding month were allocated to the LBP group (n = 36). Other subjects were allocated to the non-LBP group (n = 65). RESULTS: The LBP group had lower abdominal trunk and knee extensor muscle strength, lower serum albumin, and hemoglobin levels as blood biomarkers associated with malnutrition risk, and higher LS test scores than the non-LBP group. A multivariate analysis showed that abdominal trunk muscle weakness and advanced LS were associated with LBP. LBP intensity was negatively correlated with abdominal trunk and knee extensor muscle strength and positively correlated with the LS test score. The serum hemoglobin level was negatively correlated with the LS test score. CONCLUSION: Abdominal trunk muscle weakness and decreased mobility function were associated with LBP among older women.

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.

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.

Incidence and Risk Factors for Unplanned Return to the Operating Room Following Primary Definitive Fusion for Pediatric Spinal Deformity: A Multicenter Study with Minimum 2-year Follow-Up.

STUDY DESIGN: A retrospective multicenter cohort study. OBJECTIVE: The aim of this study was to identify the incidence and risk factors for UPROR within minimum 2-year follow-up in primary definitive fusion for pediatric spinal deformity. SUMMARY OF BACKGROUND DATA: Several previous reports have elucidated the incidence of complications after pediatric scoliosis surgery; however, there has been no study that described the incidence and risk factors for unplanned return to the operating room (UPROR) with long-term follow-up in surgery for pediatric scoliosis with every etiology. METHODS: We retrospectively extracted data of patients aged <19 years, from 14 institutes in Japan, who underwent primary definitive fusion surgery for spinal deformity between January 1, 2015 and December 31, 2017. The primary outcomes were the incidence of UPROR within the minimum 2-year follow-up period for any reason. Univariate and multivariate logistical analyses were conducted to identify potential risk factors associated with UPROR. RESULTS: We identified 1417 eligible patients (287 males and 1130 females) with a mean age of 13.9 years. UPROR for any reason within minimum 2-year follow-up was identified in 68 patients (4.8%). The most frequent cause for UPROR was implant failure found in 29 patients, followed by surgical site infection in 14 patients, junctional problems in 10 patients, and neurological complications in six patients. The multivariate logistic regression analysis revealed that a diagnosis of kyphosis (odds ratio [OR], 2.65; 95% confidence interval [CI] 1.16-6.04), etiology of congenital or structural type (OR 2.21; 95% CI 1.08-4.53), etiology of syndromic type (OR 2.67; 95% CI 1.27-5.64), and increased operation time of ≥300 minutes (OR 1.81; 95% CI 1.07-3.07) were the risk factors for the incidence of UPROR. CONCLUSION: The present multicenter study identified for the first time the incidence and risk factors for UPROR with minimum 2-year follow-up after primary definitive fusion surgery for pediatric spinal deformity with every etiology.Level of Evidence: 3.

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.

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.

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.

More Than 10-year Follow-up After Laminoplasty and Pedicle Screw Fixation for Cervical Myelopathy Associated With Athetoid Cerebral Palsy.

STUDY DESIGN: Retrospective case series. OBJECTIVE: The aim of this study was to investigate the clinical outcomes >10 years following laminoplasty and pedicle screw fixation for cervical myelopathy associated with athetoid cerebral palsy (CP). SUMMARY OF BACKGROUND DATA: Surgery for cervical myelopathy associated with CP remains a challenge because of perioperative instrumentation failure and adjacent segment problems due to patients' repetitive involuntary neck movements with deformity of the cervical spine. METHODS: A single-center series of 14 patients were reviewed. The patients comprised seven women and seven men with a mean age of 52 years at the time of surgery. The mean follow-up period was 12.5 years. The Barthel index (BI), which shows independence in activities of daily life, and Japanese Orthopaedic Association (JOA) score were assessed. Radiographic evaluation included changes of the C2-C7 angle in the sagittal plane, fusion rate, adjacent segment degeneration, and instrument failure. RESULTS: The 10-year BI and JOA score significantly improved at 36% and 31%, respectively. The preoperative Cobb angle of the sagittal plane from C2-C7 measured 11.9° of kyphosis, which improved to 0.8° of lordosis. In the radiographic analysis, 35% (proximal) and 21% (distal) of the adjacent segment showed progression in degeneration of more than one grade after 10 years. More than 90% of the patients who underwent magnetic resonance imaging showed progressive disc degeneration on either side after 10 years. Autofusion inside the disc or anterior vertebral bony bridging was observed in 86% of intervertebral levels without anterior procedures. CONCLUSION: The procedure showed favorable initial stability and maintained favorable clinical outcomes in patients with CP. More than 90% of the patients showed disc degeneration on either side. The rate of proximal adjacent segment degeneration was higher than that of distal segments with or without symptoms at the >10-year follow-up. LEVEL OF EVIDENCE: 4.

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.

Indication for anterior spinal cord decompression via a posterolateral approach for the treatment of ossification of the posterior longitudinal ligament in the thoracic spine: a prospective cohort study.

PURPOSE: For ossification of the posterior longitudinal ligament (OPLL) in the thoracic spine, anterior decompression is the most effective method for relieving spinal cord compression. The purpose of this study was to prospectively analyze the surgical outcomes based on our strategy in the treatment of thoracic OPLL. METHODS: This study included 23 patients who underwent surgery for thoracic OPLL based on the following strategy between 2011 and 2017. For patients with a beak-type OPLL in the kyphotic curve with a ≥ 50% canal occupying ratio, circumferential decompression via a posterolateral approach and fusion (CDF) was indicated. For other types of OPLL, posterior decompression and fusion (PDF) was commonly indicated. Posterior fusion without decompression (PF) was applied when the spinal cord was separated from the posterior spinal elements. Clinical and radiological outcomes were compared among the CDF, PDF, and PF groups with a minimum of 20-month follow-up. RESULTS: Ten, eleven, and two patients underwent CDF, PDF, and PF, respectively. The preoperative Japanese Orthopedic Association (JOA) score in the CDF group was significantly lower than that in the PDF group. The average recovery rate, according to JOA score, was 63%, 56%, and 25% in the CDF, PDF, and PF groups, respectively. The result in the CDF group was better than that in the PF group. CONCLUSIONS: Anterior decompression was appropriate for patients with localized spinal cord compression by a large OPLL in the kyphotic curve, and CDF via a posterolateral approach appears to be safe and effective. These slides can be retrieved under Electronic Supplementary Material.

Correlation between osteoporotic vertebral fracture and abdominal trunk muscle strength in middle-aged and older women.

We investigated the correlation between abdominal trunk muscle strength and spinal deformities in middle-aged and older women. The results indicated that abdominal trunk muscle weakness, older age, and low lumbar bone mineral density were significant risk factors associated with the presence of OVFs in the lower thoracic and lumbar spine. PURPOSE: We developed an innovative exercise device for the abdominal trunk muscles that also measures muscle strength. We investigated the correlation between the strength and thoracolumbar spinal deformity in middle-aged and older women. METHODS: This study included 206 consecutive female patients who were 50 years or older and scheduled to undergo surgery for degenerative diseases of the lower extremities. Patients with a history of symptomatic osteoporotic vertebral fractures (OVFs) requiring treatments were excluded. Before surgery, patients underwent physical measurements including abdominal trunk muscle strength using our device, full-spine standing radiography, and bone mineral density measurement of the lumbar spine (L-BMD). According to radiographic findings of the radiogram, patients were divided into four groups: control group (n = 134), listhesis group (n = 29), scoliosis group (n = 19), and fracture group (n = 24). The Tukey-Kramer honestly significant difference test was used to compare all measurements among the four groups. To identify factors associated with the presence of OVFs, a multivariate logistic regression analysis was performed. RESULTS: The average abdominal trunk muscle strength in the fracture group was significantly lower than that of the control group. The multivariate analysis revealed that abdominal trunk muscle weakness, older age, and a low L-BMD were associated with OVF findings. CONCLUSIONS: Abdominal trunk muscle weakness in middle-aged and older women was associated with OVF. The strength measurement can be a risk assessment of OVF.

Fluoroscopy-assisted posterior percutaneous reduction for the management of unilateral cervical facet dislocations after unsuccessful closed reduction: A case report.

INTRODUCTION: In some cases of cervical facet dislocations, open reduction becomes imperative when closed reduction fails. In these cases, posterior open reduction with subsequent posterior fixation has been favored in previous reports as reduction using the posterior approach is less challenging than that using the anterior approach. However, it invades the posterior cervical muscles, is associated with a high risk of postoperative axial neck pain, and is less likely to restore cervical lordosis than anterior surgery. In this report, we describe a novel reduction technique, posterior percutaneous reduction, which can address this dilemma. PRESENTATION OF CASE: An attempt to perform closed reduction in a 19-year-old adolescent with a unilateral facet dislocation at the C4-C5 level was unsuccessful. To preserve the posterior cervical muscles and obtain good cervical alignment, we opted for posterior percutaneous reduction and subsequent anterior cervical discectomy and fusion instead of posterior open reduction and fixation. An elevator was inserted into the locked facet percutaneously with fluoroscopic assistance, and reduction was achieved by lever action. Seven days after the percutaneous reduction, anterior cervical discectomy and iliac bone grafting with plate fixation were performed. There were no complications or neurological deficits postoperatively. DISCUSSION: This report describes the case of a patient who underwent anterior cervical discectomy and fusion after posterior percutaneous reduction with preservation of the posterior cervical muscles for unilateral facet dislocation when closed reduction was unsuccessful. CONCLUSION: Posterior percutaneous reduction could be a useful option for the management of cervical facet dislocations.