辻 崇

STUDY DESIGN: Prospective, multicenter, nationwide study. OBJECTIVE: To investigate perioperative complications and risk factors in surgery for thoracic ossification of the posterior longitudinal ligament (T-OPLL) using data from the registry of the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament. SUMMARY OF BACKGROUND DATA: There is no prospective multicenter study of surgical complications and risk factors for T-OPLL, and previous multicenter retrospective studies have lacked details. METHODS: Surgical methods, preoperative radiographic findings, pre- and postoperative thoracic myelopathy (Japanese Orthopaedic Association [JOA] score), prone and supine position test (PST), intraoperative ultrasonography, and intraoperative neurophysiological monitoring (IONM) were investigated prospectively in 115 cases (males: 55, females: 60, average age 53.1 y). Factors related to perioperative complications and risk factors for postoperative motor palsy were identified. RESULTS: Posterior decompression and fusion with instrumentation with or without dekyphosis was performed in 85 cases (74%). The JOA recovery rate at 1 year after surgery in all cases was 55%. Motor palsy occurred postoperatively in 37 cases (32.2%), with a mean recovery period of 2.7 months. A long recovery period for postoperative motor palsy was significantly associated with a high number of T-OPLL levels (P < 0.0001), lower preoperative JOA score (P < 0.05), and greater estimated blood loss (P < 0.05). Perioperative complications or postoperative motor palsy were significantly related to a higher number of T-OPLL levels, comorbid ossification of ligamentum flavum rate, lower preoperative JOA score, higher preoperative positive PST rate, more surgical invasiveness, a lower rate of intraoperative spinal cord floating in ultrasonography, and higher rate of deterioration of IONM. CONCLUSION: This study firstly demonstrated the perioperative complications with high postoperative motor palsy rate in a nationwide multicenter prospective study. Surgical outcomes for T-OPLL should be improved by identifying and preventing perioperative complications with significant risk factors. LEVEL OF EVIDENCE: 3.

Background: Cost-utility analysis of surgery for degenerative lumber spondylolisthesis (DS) is essential for healthcare providers and patients to select appropriate treatment. The purpose of this study was to review the cost-utility of decompression alone versus decompression with fusion for DS. Methods: A retrospective review of 99 consecutive patients who were treated for Meyerding grade 1 DS at two representative spine centers was performed. Patients with significant spinal instability were treated by decompression with fusion (F group, 40 patients) all others were treated by decompression surgery alone (D group, 59 patients). All patients were followed for three years. Demographic and radiographic data, health-related quality of life (HRQoL), and the direct cost for surgery were analyzed, and the incremental cost-effectiveness ratio (ICER) was determined using cost/quality-adjusted life years (QALY). Results: There were no differences between the groups in baseline demographics (D vs. F: age 68 ± 9 vs. 66 ± 7 years 37% vs. 40% female) or HRQoL (ODI: D, 41 ± 16 vs. F, 46 ± 13%). The F group had a higher initial-surgery cost ($18,992 ± 2932) but lower reoperation frequency (7%) than the D group ($7660 ± 2182 and 12%, respectively). The three-year total direct cost was higher for F than for D ($19,222 ± 3332 vs. $9668 ± 6,168, p =.01). ICER was higher for F at one year ($136,408 ± 187,911 vs. $237,844 ± 212,049, p &lt .01), but was comparable for F and D at three years (D, $41,923 ± 44,503 vs. F, $51,313 ± 32,849, p =.17). Conclusion: At the three-year follow-up, the two methods had comparable cost-utility. Both methods were cost-effective (defined as an ICER within three times the per-capita gross domestic product).

Purpose: Hinge-like hyper-mobility is occasionally observed at the atlanto-occipital (O-C1) joint. However, it has not been clear if this kind of hinge-like hyper-mobility at the O-C1 joint should be regarded as “pathologic”, or referred to as “instability”. To solve this issue, we aimed to establish a reliable radiographic assessment method for this specific type of O-C1 instability and figure out the “standard value” for the range of motion (ROM) of the O-C1 joint. Methods: To figure out the standard range of the O-C1 angle, we acquired magnetic resonance imaging (MRI) sagittal views of the cervical spine for 157 healthy volunteers [average: 37.4 year-old (yo)] without spine diseases, at neutral, maximum flexion and maximum extension positions. Results: The average value (AVE) for ROM of O-C1 angle was 9.91°. The standard value for ROM of O-C1 angle was calculated as 0°–21°. There was no statistically significant gender difference. We also found that the older population (≧ 40 yo) significantly had a larger ROM of O-C1 angle (AVE: 11.72°) compared to the younger population (&lt  40 yo) (AVE: 8.99°). Conclusions: We consider that hinge-like instability at O-C1 joint, which cannot be assessed by measuring Powers ratio, can be assessed by measuring the range of O-C1 angles using dynamic-MRI. Evaluation of O-C1 instability is important especially when we perform surgical treatment for diseases with upper cervical instability (such as retro-odontoid pseudotumor). We consider that the current study provides important information in such a case.

Although the number of patients with intervertebral disc (IVD) degeneration is increasing in aging societies, its etiology and pathogenesis remain elusive and there is currently no effective treatment to prevent this undesirable condition. The unfolded protein response (UPR) is a cellular machinery that plays critical roles in handling endoplasmic reticulum (ER) stress, a condition caused by the accumulation of unfolded proteins in the ER lumen. This study aimed to elucidate the potential role of the UPR mediated by pancreatic endoplasmic reticulum kinase (PERK), one of the major ER stress sensors in mammalian cells, in the development of IVD degeneration. IVD degeneration was artificially induced in Wister rats by percutaneously puncturing the coccyx IVDs and human IVDs were collected from patients who underwent spinal surgery. Expression of the UPR target genes was elevated in degenerative IVDs in both humans and rats. The induction of ER stress in annulus fibrosus cells significantly increased the transcripts for tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) in a nuclear factor (NF)-κB pathway-dependent manner. The expression of TNF-α and IL-6 was significantly reduced by treatment with a selective PERK inhibitor, GSK2606414, and by gene silencing against PERK and activating transcription factor 4 (ATF4) transcripts. Our findings indicate that the UPR mediated by the PERK pathway is causally related to the development of IVD degeneration, suggesting that PERK may be a potential molecular target for suppressing the degenerative changes in IVDs. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1334–1345, 2018.

Study Design. Single-center retrospective analysis of consecutively collected data. Objective. To determine the clinical characteristics of idiopathic spinal epidural lipomatosis (SEL). Summary of Background Data. SEL is associated with the overt accumulation of nonencapsulated adipose tissue in the epidural space, leading to spinal cord or nerve root compression. The etiology of this condition is currently not completely understood. Methods. Data of 166 male patients who underwent primary surgery for lumbar spinal canal stenosis (LSS) from May 2013 to February 2016 were retrospectively reviewed. Participants were divided into three groups based on the degree of epidural lipomatous lesion. Patient data of age at surgery, body mass index, prevalence of common noncommunicable diseases, blood tests, arteriosclerotic index, and preoperative clinical scores (assessed using the Japanese Orthopedic Association Back Pain Evaluation Questionnaire) were evaluated. Multivariate analysis was performed to assess the potential associated factors for idiopathic SEL. Results. Patients with LSS with severe SEL had a significantly higher body mass index and elevated serum levels of total cholesterol and triglyceride compared with those without SEL. Analysis of preoperative clinical scores revealed that patients with SEL experienced pain more frequently and showed less walking ability than did those without SEL. Multivariate analysis revealed that hyperlipidemia was significantly associated with idiopathic SEL (odds ratio =3.74, 95% confidence interval =1.31-10.64). Conclusion. Our data suggest that aberrant lipid metabolism is related to the pathogenesis of idiopathic SEL and that patients with LSS with idiopathic SEL have more severe pain than do those without SEL.

Background: In patients with ossification of the posterior longitudinal ligament (OPLL) in the cervical spine, it is well known that the thoracic ossified lesions often coexist with the cervical lesions and can cause severe myelopathy. However, the prevalence of OPLL at each level of the thoracic and lumbar spinal segments is unknown. The aims of this study were to investigate how often OPLL occurs at each level in the thoracolumbar spine in patients with a radiological diagnosis of cervical OPLL and to identify the spinal levels most likely to develop ossification. Methods: Data were collected from 20 institutions in Japan. Three hundred and twenty-two patients with a diagnosis of cervical OPLL were included. The OPLL index (OP index), defined as the sum of the vertebral body and intervertebral disc levels where OPLL is present, was used to determine disease severity. An OP index ≥20 was defined as severe OPLL. The prevalence of OPLL at each level of the thoracic and lumbar spinal segments was calculated. Results: Women were more likely to have ossified lesions in the thoracolumbar spine than men. Severe OPLL was significantly more common in women than in men (20% vs. 4.5%). For thoracic vertebral OPLL, the most frequently affected was the T1 segment in both men and women, followed by the T1/2 and T3/4 intervertebral levels in men and women, respectively. Ossified lesions were frequently seen at the intervertebral and vertebral levels around the cervicothoracic and thoracolumbar junctions in men with severe OPLL, whereas OPLL was more diffusely distributed in the thoracic spine in women with severe OPLL. Conclusion: Thoracolumbar OPLL occurred most often at T1 in men and at T3/4 in women. In severe OPLL cases, although ossified lesions were frequently seen at the intervertebral and vertebral levels around the cervicothoracic and thoracolumbar junctions in men, OPLL could be observed more diffusely in the thoracic spine in women.

This retrospective cohort study was designed to validate the reliability of measurement of the lateral capitellohumeral angle (LCHA), an index of sagittal angulation of the elbow, in healthy children. The results were compared to the Baumann angle (BA), which is a similar concept to LCHA. Sixty-two radiographs of the elbow in healthy children (range, 2-11 years) were reviewed by 6 examiners at 2 sessions. The mean value and reliability of the measurement of LCHA and BA were assessed. Intraobserver reliability and interobserver reliability were calculated using intraclass correlation coefficients (ICCs). The mean LCHA value was 45° (range, 22° to 70°) and the mean BA was 71° (range, 56° to 86°). The ICCs for intraobserver reliability of the LCHA measurements were almost perfect for 2 examiners, substantial for 3 examiners, and moderate for 1 examiner with a mean value of 0.77 (range, 0.57-0.95). For BA measurements, the ICCs were almost perfect for 1 examiner and substantial for 5 examiners with a mean value of 0.74 (range, 0.66-0.83). The ICCs for interobserver reliability between the first and second measurements were both moderate for LCHA (0.56 and 0.51) and for BA (0.52 and 0.50). LCHA showed almost the same reliability in measurement as BA, which is the gold standard assessment for coronal alignment of the elbow. LCHA showed moderate-to-good reliability in the evaluation of sagittal plane elbow alignment.

Study Design: Multicenter retrospective study. Background: Postoperative surgical site infection is one of the most serious complications following spine surgery. Previous studies do not appear to have investigated pyogenic discitis following lumbar laminectomy without discectomy. This study aimed to identify risk factors for postoperative pyogenic discitis following lumbar decompression surgery. Methods: We examined data from 2721 patients undergoing lumbar laminectomy without discectomy in five hospitals from April 2007 to March 2012. Patients who developed postoperative discitis following laminectomy (Group D) and a 4: 1 matched cohort (Group C) were included. Fisher's exact test was used to determine risk factors, with values of p &lt; 0.05 considered statistically significant. Results: The cumulative incidence of postoperative discitis was 0.29% (8/2721 patients). All patients in Group D were male, with a mean age of 71.6 +/- 7.2 years. Postoperative discitis was at L1/2 in 1 patient, at L3/4 in 3 patients, and at L4/5 in 4 patients. Except for 1 patient with discitis at L1/2, every patient developed discitis at the level of decompression. The associated pathogens were methicillin-resistant Staphylococcus aureus (n = 3, 37.5%), methicillin-susceptible Staphylococcus epidermidis (n = 1, 12.5%), methicillin-sensitive S. aureus (n = 1, 12.5%), and unknown (n = 3, 37.5%). In the analysis of risk factors for postoperative discitis, Group D showed a significantly lower ratio of patients who underwent surgery in the winter and a significantly higher ratio of patients who had Modic type 1 in the lumbar vertebrae compared to Group C. Conclusions: Although further prospective studies, in which other preoperative modalities are used for the evaluation, is needed, our data suggest the presence of Modic type 1 as a risk factor for discitis following laminectomy. Latent pyogenic discitis should be carefully ruled out in patients with Modic type 1. If lumbar laminectomy is performed for such patients, more careful observation is necessary to prevent the development of postoperative discitis. (C) 2017 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

OBJECTIVE A number of studies have reported that surgery for cervical intramedullary tumors via the posterior approach can result in postoperative sagittal malalignment of the cervical spine; however, the risk factors remain unclear. The purpose of this study was to investigate the changes in cervical spinal alignment after surgery for cervical intramedullary tumors in adults and to elucidate the risk factors for cervical spinal sagittal misalignment. METHODS Data for the period from April 2001 to December 2011 for all adults who had undergone surgery for cervical intramedullary spinal cord tumors at a single institution were retrospectively analyzed to determine the postoperative changes in cervical spine alignment. Patients younger than 20 years of age and those who required postoperative radiotherapy were excluded from the study. Patients were divided into 2 groups according to tumor location: upper tumor (U) group, in which the central region of the tumor was above the C-5 level; and lower tumor (L) group, in which the central region of the tumor was at or below the C-5 level. Changes in alignment of the cervical spine were measured on plain lateral radiographs. Data on atrophy of the deep extensor muscles (DEMs), tumor location, detachment of the DEMs from the C-2 spinous process, the C2-7 angle before surgery, patient age at surgery, tumor histology, patient sex, tumor size, and number of laminae affected were reviewed for each patient, and the correlation of each of these factors with cervical spinal malalignment was evaluated using statistical analysis. RESULTS The 54 adults eligible for analysis had a mean age of 49.1 years. Ependymoma was the most common cervical intramedullary tumor (63.0%) in this series. In the tumor location U group, the kyphotic angle of the C2-7 spinal segments increased after surgery (-5.8 degrees +/- 2.8 degrees). In contrast, in the L group, the C2-7 lordotic angle increased after surgery (6.4 degrees +/- 2.6 degrees). In the univariate analysis, atrophy of the DEMs, detachment of the DEMs from the C-2 spinous process, and an upper cervical location of the tumor were identified as factors significantly correlated with the development of cervical spinal kyphosis after surgery. Multiple linear regression analysis revealed the following as risk factors for kyphotic change of the cervical spine after surgery: 1) atrophy of the DEMs after surgery (beta = -0.54, p &lt; 0.01), and 2) detachment of the DEMs from the C-2 spinous process (b = -0.37, p &lt; 0.01). CONCLUSIONS Atrophy of the DEMs after surgery and detachment of the DEMs from the C-2 spinous process are directly related to the risk of cervical spinal kyphosis after surgery for cervical intramedullary tumors in adults. Therefore, preservation of the DEMs, especially those attached to the C-2 spinous process, is important for the prevention of kyphotic malalignment of the cervical spine after surgery for intramedullary tumors.

The aim of the present study was to investigate the factors associated with C5 palsy by focusing on radiological parameters using multivariable analysis. The authors retrospectively assessed 190 patients with cervical spondylotic myelopathy treated by open-door laminoplasty. Four radiographic parameters-the number of expanded lamina, C3-C7 angle, lamina open angle and space anterior to the spinal cord-were evaluated to clarify the factors associated with C5 palsy. Of the 190 patients, 11 developed C5 palsy, giving an overall incidence of 5.8%. Although the number of expanded lamina, lamina open angle and space anterior to the spinal cord were significantly larger in C5 palsy group than those in non-palsy group, a multiple logistic regression analysis revealed that only the space anterior to the spinal cord (odds ratio 2.60) was a significant independent factor associated with C5 palsy. A multiple linear regression analysis indicated that the lamina open angle was associated with the space anterior to the spinal cord and the analysis identified the following equation: space anterior to the spinal cord (mm) = 1.54 + 0.09 x lamina open angle (degree). A cut-off value of 53.5A degrees for the lamina open angle predicted the development of C5 palsy with a sensitivity of 72.7% and a specificity of 83.2%. The larger postoperative space anterior to the spinal cord, which was associated with the lamina open angle, was positively correlated with the higher incidence of C5 palsy.

Control of phosphate metabolism is crucial to regulate aging in mammals. Klotho is a well-known anti-aging factor that regulates phosphate metabolism: mice mutant or deficient in Klotho exhibit phenotypes resembling human aging. Here we show that ectonucleotide pyrophosphatase/phosphodiesterase 1 (Enpp1) is required for Klotho expression under phosphate overload conditions. Loss-of-function Enpp1(ttw/ttw) mice under phosphate overload conditions exhibited phenotypes resembling human aging and Klotho mutants, such as short life span, arteriosclerosis and osteoporosis, with elevated serum 1,25(OH)(2)D-3 levels. Enpp1(ttw/ttw) mice also exhibited significantly reduced renal Klotho expression under phosphate overload conditions, and aging phenotypes in these mice were rescued by Klotho overexpression, a low vitamin D diet or vitamin D receptor knockout. These findings indicate that Enpp1 plays a crucial role in regulating aging via Klotho expression under phosphate overload conditions.

Study Design. Laboratory study. Objective. To elucidate the potential involvement of the interleukin- 6 (IL-6)/ Janus kinase (JAK)/ signal transducers and activator of transcription (STAT3) pathway in the development of intervertebral disc (IVD) degeneration. Summary of Background Data. IL-6 plays a crucial role in IVD degeneration; however, the downstream intracellular signaling of IL-6 in the IVD is not fully understood. Methods. The expression levels of IL-6 and suppressors of cytokine signaling 3 (SOCS3), a target gene of the IL-6/JAK/ STAT3 pathway, were evaluated in rat and human degenerated IVD samples. The effects of IL-6 on primary rat annulus fibrosus (AF) cells were analyzed using quantitative PCR, immunocytochemistry, and Western blotting. The potential efficacy of a JAK inhibitor, CP690,550, in neutralizing the effect of IL-6 was evaluated in vitro. Results. A high expression of IL-6 and SOCS3 was observed in both rat and human degenerated IVD samples. In rat AF cells, IL-6 markedly induced the phosphorylation of STAT3 and the expression of cyclooxygenase-2 and matrix metalloprotease-13. CP690,550 significantly suppressed the phosphorylation of STAT3 and offset the catabolic effect of IL-6 in rat AF cells. Conclusion. Our results suggest that the IL-6/ JAK/ STAT3 pathway is involved in the pathogenesis of IVD degeneration and that CP690,550 suppresses the catabolic effect of the IL-6 in the IVD.

The pathomechanism of the ligamentum flavum (LF) hypertrophy in diabetic patients with lumbar spinal canal stenosis (LSCS) remains unclear. A cross-sectional study was undertaken to investigate the mechanism of LF hypertrophy in these patients. Twenty-four diabetic and 20 normoglycemic patients with LSCS were enrolled in the study. The structure of the LF in the study subjects was evaluated using histological and immunohistochemical methods, and the levels of sorbitol, pro-inflammatory cytokines, and the fibrogenic factor, TGF-1, in the LF were analyzed. In vitro experiments were performed using NIH3T3 fibroblasts to evaluate the effect of high-glucose conditions and an aldose reductase inhibitor on the cellular production of sorbitol, pro-inflammatory factors, and TGF-1. We found that the LF of diabetic patients exhibited significantly higher levels of sorbitol and pro-inflammatory cytokines, TGF-1 and of CD68-positive staining than that of the normoglycemic subjects. The diabetic LF was significantly thicker than that of the controls, and showed evidence of degeneration. The high glucose-cultured fibroblasts exhibited significantly higher levels of sorbitol, pro-inflammatory factors, and TGF-1 compared to the low glucose-cultured cells, and these levels were dose-dependently reduced by treatment with the aldose reductase inhibitor. Taken together, our data suggests that increased sorbitol levels in the LF of diabetic patients results in increased production of pro-inflammatory and fibrogenic factor, which contribute to LF hypertrophy, and could increase the susceptibility of diabetic patients to LSCS. Furthermore, aldose reductase inhibition effectively reduced the levels of sorbitol and sorbitol-induced pro-inflammatory factor expression in high glucose-cultured fibroblasts. (c) 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1058-1066, 2017.

We describe the use of a C1 laminar screw in combination with a C2 laminar screw as a salvage technique to treat two patients, one with persistent first intersegmental artery and the other with vertebral artery occlusion after cervical spine fracture. The combined use of C1 and C2 laminar screws allows for good fixation of the atlantoaxial joint with a lower risk of vertebral artery injury therefore, it can be an alternative surgical procedure for patients with congenital or traumatic anomalous vertebral artery. Copyright

Background: Ossification of the posterior longitudinal ligament (OPLL) can cause myelopathy that is often managed surgically. Knowledge of predictors of surgical outcomes can provide decision support to surgeons. The aims of this study were to investigate the relationships between preoperative physical signs and postoperative functional outcomes in patients with OPLL and to clarify whether physical signs could predict functional outcomes. Methods: Fifty-five patients with OPLL who had undergone cervical laminoplasty were included in this study. Six physical signs including hyperreflexia, Babinski sign, sensory disturbance, grip strength, 10-s grip and release test, and bladder dysfunction, and four other factors including age, duration of symptoms, history of minor trauma and preoperative Japanese Orthopaedic Association (JOA) score were investigated as potential predictive prognostic factors using both univariate and multivariate analyses. Results: The mean recovery rate of JOA score was 62.5 +/- 32.5%. The neurological recovery rate was negatively associated with age (P = 0.002), the duration of symptoms (P = 0.002) and Babinski sign (P - 0.007), whereas it was positively correlated with grip strength (P - 0.011). Multiple logistic regression analyses revealed that age (Odds ratio: 0.89, 95% CI: 0.81-0.99) and Babinski sign (Odds ratio: 0.18, 95% CI: 0.04-0.89) were factors associated with functional outcomes. Conclusions: Satisfactory functional outcomes could be expected for patients who are young and do not exhibit the Babinski sign, showing that the Babinski sign could be useful as an indicator of the window of opportunity for achieving satisfactory functional outcomes. (C) 2016 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

Hip fracture is the most severe bone fragility fracture among osteoporotic injuries. Family history is a known risk factor for fracture and now included among criteria for osteoporosis diagnosis and treatment; however, genetic factors underlying family history favoring fracture remain to be elucidated. Here we demonstrate that a missense SNP in the ALDH2 gene, rs671 (ALDH2*2), is significantly associated with hip fracture (odds ratio = 2.48, 95% confidence interval: 1.20-5.10, p = 0.021). The rs671 SNP was also significantly associated with osteoporosis development (odds ratio = 2.04, 95% confidence interval: 1.07-3.88, p = 0.040). For analysis we enrolled 92 hip fracture patients plus 48 control subjects without bone fragility fractures with higher than -2.5 SD bone mineral density. We also recruited 156 osteoporosis patients diagnosed as below -2.5 SD in terms of bone mineral density but without hip fracture. Association of rs671 with hip fracture and osteoporosis was significant even after adjustment for age and body mass index. Our results provide new insight into the pathogenesis of hip fracture.

Osteoporosis is characterized as a metabolic disorder of bone tissue, and various metabolic markers are now available to support its diagnosis and evaluate treatment effects. Substances produced as end products of metabolomic activities are the correlated factors to the biological or metabolic status, and thus, metabolites are considered highly sensitive markers of particular pathological states, including osteoporosis. Here we undertook comprehensive serum metabolomics analysis in postmenopausal women with or without low bone mineral density (low BMD vs controls) for the first time using capillary electrophoresis/mass spectrometry. Among the metabolites tested, 57 were detected in sera. Levels of hydroxyproline, Gly-Gly and cystine, differed significantly between groups, with Gly-Gly and cystine significantly lower in the low BMD group and hydroxyproline, a reported marker of osteoporosis, significantly higher. Levels of TRACP5b, a bone resorption marker, were significantly higher in the low BMD group, supporting the study's validity. Taken together, our findings represent novel metabolomic profiling in low BMD in postmenopausal women. (C) 2016 Elsevier Inc All rights reserved.

Background: In addition to genetic factors, environmental and lifestyle factors are thought to play an important role in the onset of adolescent idiopathic scoliosis (AIS). This cross-sectional study was conducted to explore lifestyle factors related to AIS. Methods: This study included 2,759 Japanese female junior high school students who planned a secondary screening after an initial moire topography screening indicated possible scoliosis. The students and their mothers, or guardians, were asked to fill out a questionnaire consisting of 38 questions about demographic factors, lifestyle-related factors, social factors, household environment, participation in sports, health status, and factors related to the mother's pregnancy and delivery. The questionnaire was completed by 2,747 students (a 99.6% response rate). After excluding students with heart disease, neurological disease, or a congenital vertebral anomaly, 2,600 students were eligible for assessment. After undergoing a secondary screening with standing radiographs of the spine, students were assigned to the normal (control) group if radiographs showed a curve of &lt; 15 degrees or to the scoliosis group if they had a curve of &gt;= 15 degrees. The odds ratios (ORs) for AIS in relation to the possible risk or preventive factors were estimated by logistic regression analyses. Results: No lifestyle-related factor was significantly associated with AIS. However, AIS was associated with classical ballet training (OR, 1.38; 95% confidence interval [CI], 1.09 to 1.75); the odds of AIS developing increased as the child's frequency of training, number of years of experience, and duration of training in ballet increased. The OR for AIS was 1.5 times higher for participants whose mothers had scoliosis. AIS was also associated with a low body mass index (BMI). These associations remained even after mutual adjustment was performed. Conclusions: No association was found between AIS and lifestyle-related factors. However, classical ballet training, a family history of scoliosis, and low BMI may be associated with AIS.

Introduction: Although appropriate dorsal migration of the spinal cord is a desired end point of cervical laminoplasty, it is difficult to predict in advance the spinal cord position after surgery and to control it during surgery. The aim of the present study was to investigate the factors that affect postoperative spinal cord position after cervical laminoplasty using multivariable analysis. Materials and methods: We retrospectively assessed 56 consecutive patients with cervical spondylotic myelopathy treated by open-door laminoplasty. The postoperative anterior space of the spinal cord was measured at 204 levels, and its maximum value was measured at 56 levels within the decompressed area. To identify the factors that regulate the postoperative spinal cord position, we evaluated seven radiological parameters, including the C3–C7 lordosis angle (LA), LA of the decompressed area, C3–C7 spinal cord lordosis angle (SCLA), SCLA of the decompressed area, spinal canal sagittal diameter at C5, number of expanded lamina, and postoperative dural sac diameter. Results: The postoperative anterior space of the spinal cord was 5.5 ± 1.4 mm, and its maximum value was 6.4 ± 1.3 mm. A multiple linear regression analysis revealed that the number of expanded laminae (standardized partial regression coefficient: β = 0.17, p = 0.009) and dural sac diameter (β = 0.43, p &lt  0.001) was significantly associated with anterior space of the spinal cord. Although these parameters were also significantly associated with the maximum value, their relative contributions were reversed β = 0.49 (p &lt  0.001) for the number of expanded laminae and 0.25 (p = 0.029) for the dural sac diameter. Conclusions: The number of expanded laminae and dural sac diameter was significantly associated with the spinal cord position after laminoplasty. These factors could help to predict spinal cord position following laminoplasty and achieve adequate indirect decompression of the spinal cord.

Background and purpose: Adolescent idiopathic scoliosis (AIS) is a structural, lateral curvature with rotation of the spine that develops around puberty. The influence of this spinal deformity on three-dimensional trunk movements during gait has not yet been elucidated. The aim of this study was to determine the influence of spinal curve pattern (single thoracic curve vs. single lumbar curve) on trunk kinematics during gait. Methods: Twenty-two patients with a single thoracic curve (Lenke type 1) and 17 patients with a single lumbar curve (Lenke type 5) were included in this study. Trunk symmetry in the sagittal, coronal, and transverse planes during gait was evaluated using an optoelectronic motion capture system. Results: In the type 1 group, the trunk was significantly rotated towards the concave side in the transverse plane during gait (mean difference of transverse rotation angle between concave side load and the convex side load, 8.8 +/- 0.6 degrees, p &lt; 0.01). In the type 5 group, the trunk was significantly rotated towards the convex side in the coronal plane throughout the stance phase of gait (mean difference of coronal inclination angle, 1.9 +/- 0.3 degrees, p &lt; 0.05). Conclusions: The AIS patients with a single thoracic curve showed asymmetrical trunk movement in the transverse plane, and patients with a single lumbar curve showed asymmetrical trunk movement in the coronal plane. These results indicate that the spinal curve pattern influenced trunk kinematics, and suggest that the global postural control strategy of patients with AIS differs according to the curve pattern. (C) 2016 Elsevier B.V. All rights reserved.

Study Design: A retrospective cohort study. Objective: This study was conducted to assess the invasiveness, efficacy, and safety of minimally invasive spine stabilization (MISt) for metastatic spinal tumor patients with short life expectancy. Summary of Background Data: Conventional open surgery for metastatic spinal tumors has the disadvantages of significant blood loss, potential infection, damage to back muscles, and extended hospital stays. The minimally invasive spine surgery has changed the treatment of metastatic spinal tumors radically and fundamentally. Materials and Methods: We retrospectively reviewed data from 50 consecutive patients registered with the Keio Spine Research Group (KSRG) who underwent posterior palliative surgery for metastatic spinal tumors from January 2009 to June 2015. Of these, 25 patients underwent MISt surgery (M group), and 25 underwent conventional open surgery (C group). The patients were assessed by demographic data, surgical invasiveness, complications, pain improvement, and neurological recovery. Results: The 2 groups did not differ significantly in baseline characteristics. The M group had significantly less blood loss (M, 340.1 mL C, 714.3 mL P=0.005), less postoperative drainage (M, 136.0 mL C, 627.0 mL P&lt 0.001), lower rates of red blood cell transfusion (M, 3 cases C, 10 cases P=0.029), and a shorter postoperative period of bed rest (M, 2.0 d C, 3.6 d P&lt 0.001), compared with the C group. The perioperative complication rates were significantly lower (P=0.012) in the M group (3 patients, 12%) than in the C group (11 patients, 44%). Neurological deficits and pain improved significantly and comparably in the 2 groups after surgery. Conclusions: MISt is a less invasive and effective alternative surgery to conventional open surgery for metastatic spinal tumors. MISt should be considered as a valid option for the treatment of metastatic spinal tumor patients with a short life expectancy. Level of Evidence: Level 3.

Study Design.Multicenter case-control study.Objective.To characterize the pathogenesis of idiopathic spinal epidural lipomatosis (SEL).Summary of Background Data.SEL is often associated with the history of steroid use or endocrine disorders; however, the pathogenesis of idiopathic SEL remains poorly understood.Methods.Sixteen patients who underwent lumbar decompression surgery due to severe idiopathic SEL were included in the study (L group, 15 men and 1 woman; mean age, 71.5 yrs). Fifteen patients without SEL, who underwent decompression surgery for lumbar canal stenosis, were selected as controls (C group, 14 men and 1 woman; mean age, 70.3 yrs). The following parameters were analyzed in these two groups: body mass index (BMI), medical history, histology, the size of adipocytes in the epidural fat (EF) tissues, and the expression level of the transcripts for adiponectin, leptin, tumor necrosis factor- (TNF-), interleukin (IL)-1, IL-6, and IL-8.Results.The mean BMI of the L group was significantly higher than that of the C group (29.1 vs. 25.2kg/m(2), P=0.006), and there was a significant correlation between BMI and the width of EF in both groups. The average adipocyte size in the EF was significantly larger in the L group than in the C group (2846.8 vs. 1699.0m(2), P=0.017). Furthermore, the expression levels of the transcripts for TNF- and IL-1 in the L group were significantly higher than those in the C group [2.59-fold increase (P=0.023) and 2.60-fold increase (P=0.015), respectively].Conclusion.Our data suggest that the pathogenesis of idiopathic SEL is associated with obesity. In addition, the increased expression of two major inflammatory cytokines in the EF in the L group may indicate that SEL is causally related to chronic inflammation.Level of Evidence: 3

Background: Supra/interspinous ligaments connect adjacent spinous processes and act as a stabilizer of the spine. As with other spinal ligaments, it can become ossified. However, few report have discussed ossification supra/ interspinous ligaments (OSIL), so its epidemiology remains unknown. We therefore aimed to investigate the prevalence and distribution of OSIL in symptomatic patients with cervical ossification of the posterior longitudinal ligament (OPLL). Methods: The participants of our study were symptomatic patients with cervical OPLL who were diagnosed by standard radiographs of the cervical spine. The whole spine CT data as well as clinical parameters such as age and sex were obtained from 20 institutions belong to the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament (JOSL). The prevalence and distribution of OSIL and the association between OSIL and clinical parameters were reviewed. The sum of the levels involved by OPLL (OP-index) and OSIL (OSI-index) as well as the prevalence of ossification of the nuchal ligament (ONL) were also investigated. Results: A total of 234 patients with a mean age of 65 years was recruited. The CT-based evidence of OSIL was noted in 68 (54 males and 14 females) patients (29%). The distribution of OSIL showed a significant thoracic preponderance. In OSIL-positive patients, single-level involvement was noted in 19 cases (28%), whereas 49 cases (72%) presented multi-level involvement. We found a significant positive correlation between the OP-index grade and OSI-index. ONL was noted at a significantly higher rate in OSIL-positive patients compared to negative patients. Conclusions: The prevalence of OSIL in symptomatic patients with cervical OPLL was 29%. The distribution of OSIL showed a significant thoracic preponderance.

Introduction: Few reports have compared the clinical features and imaging characteristics of giant cell tumor and chordoma of the spine. The aim of the present study was to investigate whether the two types of tumors could be differentially diagnosed, by comparing clinical characteristics as well as magnetic resonance imaging (MRI) or computed tomography (CT) findings and then scoring the characteristic findings. Methods: A total of 18 patients were retrospectively assessed. To elucidate the characteristic findings, we investigated the following 10 items: age at diagnosis, sex, and site of occurrence for MRI findings, the pattern of tumor expansion, T1-weighted images, T2-weighted images, septal structure, and cystic changes and for CT findings, calcification or residual bone fragments and incomplete bone shells. Then, we developed a unique scoring system and investigated whether the two tumors could be differentiated by this scoring system. Results: Six items, including, age, site of occurrence, tumor expansion pattern, T2-weighted images, septal structure, and incomplete bone shells, were significantly different between giant cell tumor and chordoma patients. By using newly developed scoring system, the mean scores of 0.9 ± 0.6 (range 0–2) for giant cell tumor and 4.8 ± 1.5 (range 3–6) for chordoma patients were significantly different (P &lt  0.001), thereby allowing the differential diagnosis by setting the cutoff value to three. Conclusions: We found that the six items were useful for differentially diagnosing giant cell tumor and chordoma. These results indicate that it may be possible to distinguish the two types of tumor by scoring these items.

Whether Propionibacterium acnes (P. acnes) causes surgical-site infections (SSI) after orthopedic surgery is controversial. We previously reported that we frequently find P. acnes in intraoperative specimens, yet none of the patients have clinically apparent infections. Here, we tracked P. acnes for 6 months in a mouse osteomyelitis model. We inoculated P. acnes with an implant into the mouse femur in the implant group; the control group was treated with the bacteria but no implant. We then observed over a 6-month period using optical imaging system. During the first 2 weeks, bacterial signals were detected in the femur in the both groups. The bacterial signal completely disappeared in the control group within 28 days. Interestingly, in the implant group, bacterial signals were still present 6 months after inoculation. Histological and scanning electron-microscope analyses confirmed that P. acnes was absent from the control group 6 months after inoculation, but in the implant group, the bacteria had survived in a biofilm around the implant. PCR analysis also identified P. acnes in the purulent effusion from the infected femurs in the implant group. To our knowledge, this is the first report showing that P. acnes causes SSI only in the presence of an implant.

Intervertebral disc degeneration proceeds with age and is one of the major causes of lumbar pain and degenerative lumbar spine diseases. However, studies in the field of intervertebral disc biology have been hampered by the lack of reliable cell lines that can be used for in vitro assays. In this study, we show that a chordoma-derived cell line U-CH1-N cells highly express the nucleus pulposus (NP) marker genes, including T (encodes T brachyury transcription factor), KRT19, and CD24. These observations were further confirmed by immunocytochemistry and flow cytometry. Reporter analyses showed that transcriptional activity of T was enhanced in U-CH1-N cells. Chondrogenic capacity of U-CH1-N cells was verified by evaluating the expression of extracellular matrix (ECM) genes and Alcian blue staining. Of note, we found that proliferation and synthesis of chondrogenic ECM proteins were largely dependent on T in U-CH1-N cells. In accordance, knockdown of the T transcripts suppressed the expression of PCNA, a gene essential for DNA replication, and SOX5 and SOX6, the master regulators of chondrogenesis. On the other hand, the CD24-silenced cells showed no reduction in the mRNA expression level of the chondrogenic ECM genes. These results suggest that U-CH1-N shares important biological properties with notochordal NP cells and that T plays crucial roles in maintaining the notochordal NP cell-like phenotype in this cell line. Taken together, our data indicate that U-CH1-N may serve as a useful tool in studying the biology of intervertebral disc. (C) 2016 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society.

Background: In Japan, ossification of the posterior longitudinal ligament (OPLL) has been designated as an intractable disease by the Ministry of Health, Labour, and Welfare. Here we aimed to clarify the epidemiological characteristics of severe OPLL patients by analyzing a national registry of this disease that uses clinical investigation registration forms. Methods: We retrospectively investigated clinical investigation registration forms for 24,502 patients with OPLL. We examined the sex distribution, age of disease onset, period from disease onset to registration, family history, site of ossification as determined by plain radiographs, Japanese Orthopaedic Association score, and number of OPLL surgeries. Results: The male-to-female ratios were 2.7:1 and 1.9:1 for new and renewed registrations, respectively. The mean ages at disease onset were 61.1 and 59.7 years for new and renewed registrations, respectively. The mean periods from disease onset to registration were 2.6 and 8.4 years for new and renewed registrations, respectively. The percentages of new registrations with and without family history were 5.3% and 51.5%, respectively (unknown for 43.3%). Of the new registrations, 3511, 359, and 200 cases exhibited ossification in the cervical spine, thoracic spine, and lumbar spine, respectively; the corresponding numbers for renewed registrations were 13,710, 2484, and 1508. The Japanese Orthopaedic Association score was 9.9 +/- 3.6 for new registrations, and the mean score recovery rate for renewed registrations was 6.0%. The number of OPLL surgeries was one or zero, two, three, four, or five for 21,785, 2167, 412, 99, and 39 patients, respectively, with 11.1% of all patients having undergone multiple surgeries. Conclusions: This study offers new insight into the epidemiological characteristics of severe OPLL. In particular, we found that the age of disease onset was higher than previously reported, the period from disease onset to registration (surgery) was relatively short, and about 90% of the patients required only a single surgery. (C) 2016 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

Background: Although various risk factors have been reported for adjacent segment degeneration after lumbar fusion, the exact mechanisms and risk factors related to adjacent segment degeneration have not been clear. The present study was conducted to evaluate the risk factors for radiological adjacent segment degeneration in patients surgically treated for single-level L4 spondylolisthesis focusing on a single pathology, a specific fusion level, at a set interval. Methods: We assessed preoperative and five-year postoperative radiographs for 72 patients who underwent L4-5 anterior or posterior lumbar interbody fusion for single-level L4 degenerative spondylolisthesis. Adjacent segment degeneration was defined as imaging evidence of one or more of the following conditions at L1-2, L2-3, or L3-4: 1) a loss of more than 20% of the preoperative disc height, 2) anterolisthesis or retrolisthesis greater than 3 mm, 3) or osteophyte formation greater than 3 mm. Results: We found adjacent segment degeneration in 21 patients, with 31 discs affected. Multiple logistic regression analysis identified the following significant independent risk factors for adjacent segment degeneration: female gender (odds ratio 10.80; 95% confidence interval 1.20-96.89), posterior lumbar interbody fusion (odds ratio 7.70; 95% confidence interval 1.82-32.66), and pre-existing disc degeneration (odds ratio 12.29; 95% confidence interval 1.69-89.27). Conclusions: Female gender, posterior lumbar interbody fusion, and pre-existing disc degeneration were significant independent risk factors for radiologically diagnosed adjacent segment degeneration in patients treated for L4 degenerative spondylolisthesis by interbody lumbar fusion. (C) 2015 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

Various silver-coated implants have been developed to prevent implant-associated infections, and have shown dramatic effects in vitro. However, the in vivo results have been inconsistent. Recent in vitro studies showed that silver exerts antibacterial activity by mediating the generation of reactive oxygen species in the presence of oxygen. To maintain its antibacterial activity in vivo, the silver should remain in an ionic state and be stably bound to the implant surface. Here, we developed a novel bacteria-resistant hydroxyapatite film in which ionic silver is immobilized via inositol hexaphosphate chelation using a low-heat immersion process. This bacteria-resistant coating demonstrated significant antibacterial activity both in vitro and in vivo. In a murine bioluminescent osteomyelitis model, no bacteria were detectable 21 days after inoculation with S. aureus and placement of this implant. Serum interleukin-6 was elevated in the acute phase in this model, but it was significantly lower in the ionic-silver group than the control group on day 2. Serum C-reactive protein remained significantly higher in the control group than the ionic-silver group on day 14. Because this coating is produced by a low-heat immersion process, it can be applied to complex structures of various materials, to provide significant protection against implant-associated infections.

Objective: The purpose of this study is to identify factors that affect survival of patients with differentiated thyroid carcinoma with bone metastases and to optimize surgical treatment modality for bone metastatic lesion by comparing duration of patient survival and local control. Methods: We examined 52 bone metastatic lesions from 40 patients with differentiated thyroid carcinoma who were treated surgically between 1994 and 2008 at Keio University Hospital. Median follow-up time was 46 months (range: 4-233 months). Patients' disease-specific survival, local control duration and factors that potentially affected disease-specific survival after bone metastasis surgery were statistically analyzed. Results: The 2-, 5-and 10-year disease-specific survival rates were 77.2, 64.3 and 45.7%, respectively. Factors that were significantly associated with poor survival rates in multivariate analyses included age at bone metastasis surgery &gt;= 65 years (P = 0.0068), time from diagnosis of primary cancer to bone metastasis surgery &gt;= 5 years (P = 0.0018) and presence of visceral metastases (P = 0.0092). The 2-, 5-and 10-year local control rates in our series were 91.4, 72.7 and 63.6%, respectively. The 5-year local control rates for radical and palliative surgery were 84.4 and 55.3%, respectively, and differed significantly (P = 0.019). Conclusions: Because disease-specific survival of patients with differentiated thyroid carcinoma is fairly good, inadequate treatment of bone metastatic lesions can result in severe disabilities. Therefore, radical surgery for bone metastatic lesions should be considered, especially for those with favorable prognostic factors.

Ossification of the posterior longitudinal ligament of the spine (OPLL) is a common spinal disorder among the elderly that causes myelopathy and radiculopathy. To identify genetic factors for OPLL, we performed a genome-wide association study (GWAS) in similar to 8,000 individuals followed by a replication study using an additional similar to 7,000 individuals. We identified six susceptibility loci for OPLL: 20p12.3 (rs2423294: P = 1.10 x 10(-13)), 8q23.1 (rs374810: P = 1.88 x 10(-13)), 12p11.22 (rs1979679: P = 4.34 x 10(-12)), 12p12.2 (rs11045000: P = 2.95 x 10(-11)), 8q23.3 (rs13279799: P = 1.28 x 10(-10)) and 6p21.1 (rs927485: P = 9.40 x 10(-9)). Analyses of gene expression in and around the loci suggested that several genes are involved in OPLL etiology through membranous and/or endochondral ossification processes. Our results bring new insight to the etiology of OPLL.

Ossification of the posterior longitudinal ligament (OPLL) is most frequently seen in the cervical spine. The types of cervical OPLL are classified into continuous, mixed, segmental, and other based on plain lateral X-ray. Computed tomography (CT) imaging is often used in clinical practice for evaluating ossified lesions as it can detect their precise location, size, and shape. However, to date, no CT classification of OPLL lesions has been proposed. One hundred and forty-four patients diagnosed with cervical OPLL by plain radiograph were included in this study. Sagittal and axial CT images of the cervical spine were obtained. We propose three classification systems: A, B, and axial. Classification A comprises two lesion types: bridge and nonbridge. Classification B requires examiners to describe all vertebral and intervertebral levels where OPLL exits in the cervical spine. Axial classification comprises central and lateral lesions identified on axial CT images. Seven observers evaluated CT images using this classification system, and intra- and interrater reliability were examined. Averaged Fleiss' kappa coefficient of interrater agreement was 0.43 +/- A 0.26 among the seven observers, averaged intrarater reliability for the existence of OPLL was 72.4 +/- A 8.8 % [95 % confidence interval (CI) 67.5-76.8]. Fifty-four patients (37.5 %) had the bridge type and 90 the nonbridge type according to Classification A; 102 (70.8 %) had central and 42 (29.2 %) lateral OPLL in the axial classification. Four representative cases defined according to the three classification types are reported here. Subcommittee members of the Investigation Committee on the Ossification of the Spinal Ligaments of the Japanese Ministry of Public Health and Welfare propose three new classification systems of cervical OPLL based on CT imaging: A, B, and axial.

Study design: Retrospective case series. Objective: To evaluate our treatment strategy for cervical dumbbell neurinoma. Summary of background data: In treating cervical dumbbell neurinoma, possible difficulties include reoperation due to recurrent tumor, denervation due to nerve root resection, and postoperative spinal deformity due to extensive bony removal. Methods: We reviewed 75 cases of cervical dumbbell neurinoma that were treated surgically between 1985 and 2006. Postoperative neurological deficits, effects of surgical margins on tumor recurrence, and surgical complications were investigated retrospectively. Results: Sensory and motor deficits due to resection of specific nerve roots appeared temporarily in 33 and 23 % of all cases, and persisted in 8 and 8 % at final evaluation, respectively. Total, subtotal, and partial resection was performed in 57, 13, and 5 cases, respectively. The total resection rate was low in the tumors that had large extraforaminal components. Of the subtotally resected 13 cases, only two cases of high tumor-growth rate required re-operation or showed tumor growth. Among the five partially resected cases, re-operation was necessary in two cases 13 and 15 years later because of aggravated neurological symptoms due to tumor growth. Two patients who underwent C2 laminectomy developed kyphosis, and three patients who underwent facet joint resection and curettage of vertebral body lesions developed scoliosis. Conclusion: Total resection should be attempted for cervical dumbbell tumors. In cases where total resection was potentially of high risk, however, subtotal resection (within the capsule) was found to be a practical choice yielding favorable long-term outcome when the tumor growth rate (MIB-1 index) was low. © 2012 The Japanese Orthopaedic Association.

Ossification of the posterior longitudinal ligament of the spine (OPLL) is a common musculoskeletal disease among people after middle age. The OPLL presents with serious neurological abnormalities due to compression of the spinal cord and nerve roots. The OPLL is caused by genetic and environment factors; however, its etiology and pathogenesis still remain to be elucidated. To determine the susceptibility loci for OPLL, we performed a genome-wide linkage study using 214 affected sib-pairs of Japanese. In stratification analyses for definite cervical OPLL, we found loci with suggestive linkage on 1p21, 2p22-2p24, 7q22, 16q24 and 20p12. Fine mapping using additional markers detected the highest non-parametric linkage score (3.43, P = 0.00027) at D20S894 on chromosome 20p12 in a subgroup that had no complication of diabetes mellitus. Our result would shed a new light on genetic aspects of OPLL. © The Japanese Society for Bone and Mineral Research and Springer Japan 2012.

Background Although microendoscopic discectomy (MED) is a minimally invasive surgical method for lumbar disc herniation (LDH), early postoperative recurrence may outweigh that advantage. The purpose of the present study was to retrospectively investigate the recurrence rate after MED for LDH and to determine the risk factors for recurrence in patients treated by a single surgeon. Materials and Methods The study included 344 patients who underwent MED (213 males and 131 females mean age, 39.3 years age range, 11-82 years mean follow-up, 3.6 years follow-up range, 2.0-6.5 years). The clinical outcomes were evaluated using the Japanese Orthopedic Association Score for Low Back Pain (JOA score). Recurrence factors investigated by logistic regression analysis included age sex level, laterality, and classified type of LDH occupation sports activity and learning curve of the surgeon. Results LDH recurrence was observed in 37 patients (10.8%). It was observed at the same level in the ipsilateral side as the original LDH in 30 patients, in the contralateral side in three patients, and at a level adjacent to the original level in four patients. The mean time interval between MED and the recurrence was 16.6 months (range, 0.5-52 months). Twenty patients (54.1%) developed recurrence within 1 year after MED. Twenty-two patients (59.5%) were treated by revision surgery (MED in 20 patients and microdiscectomy in two patients), and 15 patients (40.5%) were treated conservatively. The mean JOA score of all the patients was 14.7 ± 3.5 before surgery and 26.5 ± 2.2 at the final follow-up, yielding an average recovery rate of 82.3 ± 15.7%. The recovery rate was 83.1 ± 14.8% in patients without recurrence and 75.7 ± 20.4% in patients with recurrence (p = 0.006). By logistic regression analysis, we identified migration of LDH as a significant factor related to recurrence. The patients with caudal migration of LDH had recurrence more frequently (19.0%) than those with rostral migration (12.5%) or without migration (10.2%) (p = 0.04 odds ratio, 2.0 95% confidence interval, 1.0-3.8). Conclusion The recurrence rate and reoperation rate for LDH after MED were comparable to those of conventional discectomy. More than half of the cases of recurrence occurred at an early postoperative phase, and patients with caudally migrated LDH experienced recurrence significantly more often than those with rostrally migrated or nonmigrated LDH. ©2013 Georg Thieme Verlag KG Stuttgart, New York.

To date, few studies have focused on spinopelvic sagittal alignment as a predisposing factor for the development of degenerative spondylolisthesis (DS). The objectives of this study were to compare differences in spinopelvic sagittal alignment between patients with or without DS and to elucidate factors related to spinopelvic sagittal alignment. A total of 100 patients with or without DS who underwent surgery for lumbar spinal canal stenosis were assessed in this study. Fifty patients with DS (DS group) and 50 age- and gender-matched patients without DS (non-DS group) were enrolled. Spinopelvic parameters including pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), L4 slope, L5 slope, thoracic kyphosis (TK), lumbar lordosis (LL) and sagittal balance were compared between the two groups. In the DS group, the percentage of vertebral slip (% slip) was also measured. Several spinopelvic parameters, PI, SS, L4 slope, L5 slope, TK and LL, in the DS group were significantly greater than those in the non-DS group, and PI had positive correlation with % slip (r = 0.35, p &lt; 0.05). Degrees of correlations among spinopelvic parameters differed between the two groups. In the DS group, PI was more strongly correlated with SS (r = 0.82, p &lt; 0.001) than with PT (r = 0.41, p &lt; 0.01). In the non-DS group, PI was more strongly correlated with PT (r = 0.73, p &lt; 0.001) than with SS (r = 0.38, p &lt; 0.01). Greater PI may lead to the development and the progression of vertebral slip. Different compensatory mechanisms may contribute to the maintenance of spinopelvic sagittal alignment in DS and non-DS patients.

Several biomarkers have been used to evaluate osteoarthritis of the limb joints. Here we evaluated the use of serum cartilage metabolites as biomarkers for degenerative lumbar scoliosis (DLS). Fifty-two DLS patients with Cobb angle?&gt;?10 degrees were compared with 19 control patients. Serum levels of hyaluronic acid (HA), keratan sulfate (KS), cartilage oligomeric matrix protein (COMP), collagen type II cleavage (C2C), and procollagen type II C-propeptide (CPII) were measured. Serum levels of KS (DLS 1.20 +/- 0.44 mu g/ml vs. control 0.98 +/- 0.33 mu g/ml), CPII (DLS 1905.1 +/- 948.2?ng/ml vs. control 1223.6 +/- 884.4?ng/ml), and C2C (DLS 219.1 +/- 59.2?ng/ml vs. control 177.7 +/- 71.7?ng/ml) were significantly higher in DLS. There were no significant differences in the levels of HA or COMP. There was a significant positive correlation between the Cobb angle and CPII in DLS. This is the first study to evaluate the cartilage biomarkers in DLS. The results suggest DLS patients have higher levels of type II collagen synthesis and degradation, indicated by elevated serum CPII and C2C, respectively. As type II collagen is a major component of collagens in the nucleus pulposus and facet joint cartilages, its enhanced turnover may be related to the development and progression of DLS. (C) 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:12491253, 2012

BACKGROUND: Because an idiopathic spinal extradural arachnoid cyst (SEAC) is rare, its optimal surgical treatment remains controversial. OBJECTIVE: To evaluate the results of surgical treatments for SEACs and to clarify features of the disease associated with poor outcomes. METHODS: Twelve patients with SEACs who underwent surgery at our hospital between 1988 and 2008 were examined retrospectively. The mean follow-up period was 4.7 years. Total resection of the cyst was performed in 7 patients and closure of the dural defect without cyst resection in 5 patients. Surgical outcomes were evaluated with regard to the duration of symptoms, the size of the cyst, and the surgical procedure used. RESULTS: Neurological recovery was observed in all patients, and there was no recurrence. Poor outcomes were observed in patients with a long duration of symptoms (&gt;1 year, P &lt; .01) and large cyst size (&gt;5 vertebrae, P &lt; .05). The surgical procedure had no significant association with the postoperative neurological recovery. However, there was a significant difference in the degree of the mean postoperative kyphotic angle between the patients treated by total resection of the cyst (9.7 degrees) and those treated by closure of the dural defect without cyst resection through selective laminectomy (2.2 degrees) (P &lt; .01). CONCLUSION: There was no significant difference in postoperative neurological recovery between the 2 surgical procedures. However, closure of the dural defect without cyst resection was less invasive, preventing postoperative kyphotic deformity of the thoracolumbar spine.

Object. This study was conducted to determine whether postoperative changes in the fractional anisotropy (FA) value and diffusion tensor imaging of the cervical spinal cord can predict functional outcome for patients with cervical compressive myelopathy (CCM). Methods. Twenty patients with CCM were treated by laminoplasty from 2008 to 2009. Both T2-weighted MRI and diffusion tensor imaging were performed before and after surgery. The FA values were analyzed and fiber tracking was performed. The fiber tract (FT) ratio was calculated according to the following formula: (number of fibers at the compressed level)/(number of fibers at the C-2 level) x 100%. The Japanese Orthopaedic Association scoring system for cervical myelopathy was used to determine pre- and postoperative neurological status of the patients, and the Hirabayashi method was used to calculate the recovery rate. Results. There was no significant difference in recovery rates between patients with and those without intramedullary high signal intensity on preoperative T2-weighted images. Substantial differences in FA value among spinal cord, bone, and CSF made it difficult to obtain a precise FA value for the compressed spinal cord. There was a significant correlation between the preoperative FT ratio and the recovery rate (p = 0.0006). A poor outcome (recovery rate &lt;40%) could be anticipated for CCM patients with preoperative FT ratios below 60%. Conclusions. The preoperative FT ratio correlated significantly with the recovery rates in CCM patients. Preoperative diffusion tensor tractography can be a new prognostic predictor for neurological recovery in CCM patients after laminoplasty. (http://thejns.org/doi/abs/10.3171/2012.5.SPINE1196)

Study Design. A prospective follow-up study. Objective. To elucidate the impact of lamina closure on long-term outcomes after open-door laminoplasty. Summary of Background Data. In a previous study, we did not find significant associations between lamina closure and short-term outcomes. Methods. Of the original cohort of 82 patients who underwent open-door laminoplasty, 69 were included in this study (52 men, 17 women; mean age, 60.9 yr; mean follow-up, 6.2 yr; 56 with spondylosis or disc herniation, 13 with ossification of posterior longitudinal ligament). Lamina closure was previously observed in 23 of these patients (closure group) but not in 46 (nonclosure group). The Japanese Orthopaedic Association (JOA) scores and Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire were recorded. Results. The JOA score was 9.9 +/- 3.2 in the closure group and 11.2 +/- 2.3 in the nonclosure group before surgery (P = 0.1), 13.8 +/- 2.3 and 13.8 +/- 2.2 at 1.8 years (P = 0.99), and 13.6 +/- 2.2 and 14.2 +/- 2.7 at final follow-up (P = 0.29). The recovery rate of the JOA scores was 56.7 +/- 30.0% and 46.7 +/- 29.2% at 1.8 years (P = 0.22) and 51.0 +/- 32.5 and 57.6 +/- 31.1 at the final follow-up (P = 0.42). The subdomains assessed by the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire at follow-up were cervical spine function, 68.7 +/- 27.5 in the closure group and 67.7 +/- 30.0 in the nonclosure group (P = 0.93); upper extremity function, 78.6 +/- 24.3 and 87.6 +/- 15.4 (P = 0.40); lower extremity function, 69.9 +/- 26.0 and 73.9 +/- 22.5 (P = 0.68); bladder function, 74.6 +/- 22.6 and 84.9 +/- 29.2 (P = 0.18); and quality of life, 53.9 +/- 25.3 and 56.2 +/- 18.1 (P = 0.96). Conclusion. Lamina closure did not significantly impact the long-term surgical outcomes of laminoplasty for cervical myelopathy. Although not statistically significant, the recovery rate tended to decline in the closure group compared with the nonclosure group during the long-term follow-up period, and the utilization of a laminar retention device to prevent the laminar closure should be considered.