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There are few reports concerning determinants of the surgical outcome of anterior decompression and fusion (ADF) when performed for ossification of the posterior longitudinal ligament of the thoracic spine (T-OPLL). We investigated prognostic factors associated with neurological recovery in the patients with T-OPLL.This retrospective study included consecutive cases of T-OPLL patients from January 2002 to January 2020 and minimum one-year follow-up. Data were collected for sex, age, body mass index, preoperative manual muscle test score for the weakest muscle, surgical data, and preoperative and postoperative findings on radiographs, magnetic resonance images, and computed tomography scans. Imaging data were also collected, including preoperative kyphotic angles, canal occupancy ratio, type of OPLL, and high-intensity areas on T2-weighted images. The Japanese Orthopaedic Association score for thoracic myelopathy (T-JOA) was used to evaluate the recovery of the thoracic myelopathy. The patients were categorized according to whether the improvement in T-JOA score was50% or ≤50%.Forty-six patients who underwent anterior procedures for T-OPLL were included in the study. Preoperative and postoperative T-JOA scores were 4.2 ± 2.3 and 7.9 ± 2.1, respectively. The improvement in the T-JOA score was 54.5 ± 25.6%. The proportion of patients with beak-type OPLL was significantly higher in the50% JOA improvement group (23/27) than in the ≤50% group (9/19) (p = 0.009) and the canal occupancy ratio was significantly lower in the50% group (56.3 ± 12.2% vs 64.4 ± 8.73%; p = 0.0163). There were no significant between-group differences in other factors.Beak-type ossification and a low canal occupancy ratio are predictors of good outcome after ADF in patients with T-OPLL. ADF should be considered in patients with either or both of these features.

Factors related to postoperative mechanical failure after long fusion with lower instrumented vertebra (LIV) at L5 have not been well investigated. Elucidating such factors may allow us to perform alternatives to spinopelvic fusion for adult spinal deformity (ASD) cases. We investigated the incidence and risk factors of LIV failure in patients with ASD who underwent surgical treatment of long corrective fusion until the L5 vertebrae.Between 2009 and 2018, 52 patients who underwent corrective fusions to L5 were followed-up for at least one-year. We evaluated the associated patient factors for LIV failure which include loosening of the pedicle screw of LIV, fracture of LIV, distal junctional kyphosis (DJK).The mean age of the participants was 71.2 ± 7.59 (range, 44-84). LIV failure occurred in 20 patients (38.5%), and 6 patients (11.5%) underwent secondary surgery for caudal segments. The mean pelvic incidence (PI) was 52.5 ± 9.8 in the failure group versus 45.3 ± 11.4 in non-failure group (P = 0.02) and pelvic tilt (PT) was 39.1 ± 9.0 versus 32.4 ± 13.0. There were no significant differences in sex, age, body mass index, number of levels fused, and other radiographic data. Logistic regression analysis that included T1 pelvic angle, PT, PI - postoperative LL and PI also identified PI as the only significant determinant of LIV failure (OR = 1.07, P = 0.034). Receiver operating characteristic analysis demonstrated that a PI over 50.0° was associated with LIV failure (sensitivity 63%, specificity 70%, AUC 0.694).LIV failure was frequently observed after long corrective fusion for patients with ASD. High PI was found to be a significant risk factor for the LIV failure.

Background Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by heterotopic bone formation in the posterior longitudinal ligament of the spine. Although the patients with OPLL are more common in the 60s and 70s, we know that there are markedly young patients (e.g., early 40s). However, to the best of our knowledge, there is few reports characterize young patients with cervical OPLL in terms of the imaging features, subjective symptoms, and ADL problems. Methods This is the multicenter cross-sectional study. Two hundred and thirty-seven Japanese symptomatic patients with cervical OPLL confirmed by standard X-rays collected from 16 institutions belonging to the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament formed by the Japanese Ministry of Health, Labor and Welfare were recruited. Whole spine CT data as well as demographic data such as age, gender, patients-based evaluations, and the 36-item Short Form Health Survey (SF-36) were evaluated. Results Young group (≦ 45 years old) consisted of 23 patients (8 females and 15 males), accounting for 9.7% of the total. Their characteristics were high body mass index (BMI), significant involvement of trauma in the onset and deterioration of symptoms, and the predominance of thoracic OPLL. The patient-based evaluations did not show a significant difference between the young and non-young groups, or between the genders in the young group except for bodily pain (BP) of SF-36. Female patients in young group had significantly lower BP score of SF-36 than that of male in young group. Conclusions Characteristics of young patients with cervical OPLL were high BMI, significant involvement of trauma in the onset and deterioration of symptoms, lower BP score of SF-36 in female, and the predominance of thoracic OPLL.

Introduction Anterior decompression and fusion have shown favorable neurologic outcomes in patients with cervical myelopathy. However, implant migration sometimes occurs immediately after multilevel anterior cervical corpectomy with fusion (ACCF). Risk factors associated with early bone graft migration have not been precisely documented. The study aimed to investigate how frequently bone graft subsidence occurs after ACCF and to determine the factors affecting implant migration. Methods Forty-seven consecutive patients who underwent ACCF for ossification of the posterior longitudinal ligament at our hospital between 2007 and 2015 and were able to complete 1 year of follow-up were enrolled. Patients treated with hybrid fixation were excluded. Data on demographics and radiographic findings, namely, fused segment angle and fused segment height (FSH), were collected. Implant migration was defined as subsidence of >3 mm. The patients were divided into 2-segment (2F), 3-segment (3F), and ≥4-segment (4F) groups. Results were compared between the groups using one-way analysis of variance, the Mann-Whitney U test, and the chi-square test. Results Mean age was 61.6 years in the 2F group (n = 17), 62.1 years in the 3F group (n = 21), and 69 years in the 4F group (n = 9). There were no significant between-group differences in demographics or clinical characteristics. Implant subsidence occurred in 3 cases (17.6%) in the 2F group, 4 (19%) in the 3F group, and 3 (33.3%) in the 4F group. Revision surgery was required in 2 cases (1 patient each in the 3F and 4F groups). Logistic regression analysis showed a significant association of increased FSH and increased risk of postoperative implant subsidence. Conclusions A postoperative increase in FSH may affect graft stability and lead to early implant migration.

Background Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by heterotopic bone formation in the posterior longitudinal ligament of the spine. We know that the size and distribution of the ossified lesions in patients with OPLL are different in each case. However, the characteristics of the patients with radiologically severe cervical OPLL remain unknown. Methods The participants of our study were symptomatic patients with cervical OPLL who were diagnosed by standard radiographs of the cervical spine. Whole-spine CT data and demographic data such as age and sex were obtained from 20 institutions belonging to the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament. According to the number of the levels involved by OPLL, we stratified the patients into two subgroups: severe group (S-group) and non-severe group (NS-group) to delineate the characteristics of radiologically severe patients with cervical OPLL. We also evaluated the most compressed level and the degree of occupying ratio of cervical spinal canal by OPLL at the most compressed level. Results A total of 234 patients with a mean age of 65 years were recruited. The S-group consisted of 48 patients (21%, 12 females and 36 males) and the NS-group consisted of 92 patients (79%, 22 females and 70 males). The mean age of males in the S-group (68 years old) was significantly higher than that of males in the NS-group (64 years old); however there was no significant difference in the mean age in females between the S-group (69 years old) and the NS-group (66 years old). No significant difference of body mass index, ossification of the nuchal ligament-positivity and presence of diabetes mellitus were found between the S- and the NS-group. Conclusions It is likely that the manner of extension of cervical OPLL is different between male and female patients.

Introduction: Osteoporotic vertebral fracture (OVF) is the most common osteoporotic fracture, and some patients require surgical intervention to improve their impaired activities of daily living with neurological deficits. However, many previous reports have focused on OVF around the thoracolumbar junction, and the surgical outcomes of lumbar OVF have not been thoroughly discussed. We aimed to investigate the surgical outcomes for lumbar OVF with a neurological deficit. Methods: Patients who underwent fusion surgery for thoracolumbar OVF with a neurological deficit were enrolled at 28 institutions. Clinical information, comorbidities, perioperative complications, Japanese Orthopaedic Association scores, visual analog scale scores, and radiographic parameters were compared between patients with lower lumbar fracture (L3-5) and those with thoracolumbar junction fracture (T10-L2). Each patient with lower lumbar fracture (L group) was matched with to patients with thoracolumbar junction fracture (T group). Results: A total 403 patients (89 males and 314 females, mean age: 73.8 ± 7.8 years, mean follow-up: 3.9 ± 1.7 years) were included in this study. Lower lumbar OVF was frequently found in patients with lower bone mineral density. After matching, mechanical failure was more frequent in the L group (L group: 64%, T group: 39%; p < 0.001). There was no difference between groups in the clinical and radiographical outcomes, although the rates of complication and revision surgery were still high in both groups. Conclusions: The surgical intervention for OVF is effective in patients with myelopathy or radiculopathy regardless of the surgical level, although further study is required to improve clinical and radiographical outcomes. Level of evidence: Level III

A retrospective multicenter study. Body mass index (BMI) is recognized as an important determinant of osteoporosis and spinal postoperative outcomes; however, the specific impact of BMI on surgery for osteoporotic vertebral fractures (OVFs) remains inconclusive. This retrospective multicenter study investigated the impact of BMI on clinical outcomes following fusion surgery for OVFs. 237 OVF patients (mean age, 74.3 years; 48 men and 189 women) with neurological symptoms who underwent spinal fusion were included in this study. Patients were grouped by World Health Organization BMI categories: low BMI (18.5 kg/m2), normal BMI (≥18.5 and 25 kg/m2), and high BMI (≥25 kg/m2). Patients' backgrounds, surgical method, radiological findings, pain measurements, activities of daily living (ADL), and postoperative complications were compared after a mean follow-up period of 4 years. As results, the proportion of patients able to walk independently was significantly smaller in the low BMI group (75.0%) compared with the normal BMI group (89.9%; P = .01) and the high BMI group (94.3%; P = .04). Improvement in the visual analogue scale for leg pain was significantly less in the low BMI group than the high BMI group (26.7 vs 42.8 mm; P = .046). Radiological evaluation, the Frankel classification, and postoperative complications were not significantly different among all 3 groups. Improvement of pain intensity and ADL in the high BMI group was equivalent or non-significantly better for some outcome measures compared with the normal BMI group. Leg pain and independent walking ability after fusion surgery for patients with OVFs improved less in the low versus the high BMI group. Surgeons may want to carefully evaluate at risk low BMI patients before fusion surgery for OVF because poor clinical results may occur.

Background: Although diffuse idiopathic skeletal hyperostosis (DISH) is known to coexist with the ossification of spinal ligaments (OSLs), details of the radiographic relationship remain unclear. Methods: We prospectively collected data of 239 patients with symptomatic cervical ossification of the posterior longitudinal ligament (OPLL) and analyzed the DISH severity on whole-spine computed tomography images, using the following grades: grade 0, no DISH, grade 1, DISH at T3–T10, grade 2, DISH at both T3–T10 and C6–T2 and/or T11–L2, and grade 3, DISH beyond C5 and/or L3. Ossification indices were calculated as the sum of vertebral and intervertebral levels with OSL for each patient. Results: DISH was found in 107 patients (44.8%), 65 (60.7%) of whom had grade 2 DISH. We found significant associations of DISH grade with the indices for cervical OPLL (r = 0.45, p &lt, 0.0001), thoracic ossification of the ligamentum flavum (OLF, r = 0.41, p &lt, 0.0001) and thoracic ossification of the supra/interspinous ligaments (OSIL, r = 0.53, p &lt, 0.0001). DISH grade was also correlated with the index for each OSL in the whole spine (OPLL: r = 0.29, p &lt, 0.0001, OLF: r = 0.40, p &lt, OSIL: r = 0.50, p &lt, 0.0001). Conclusion: The DISH grade correlated with the indices of OSL at each high-prevalence level as well as the whole spine.

Background: This study investigated how diffuse idiopathic skeletal hyperostosis (DISH) influences clinical characteristics in patients with cervical ossification of the posterior longitudinal ligament (OPLL). Although DISH is considered unlikely to promote neurologic dysfunction, this relationship remains unclear. Methods: Patient data were prospectively collected from 16 Japanese institutions. In total, 239 patients with cervical OPLL were enrolled who had whole-spine computed tomography images available. The primary outcomes were visual analog scale pain scores and the results of other self-reported clinical questionnaires. Correlations were sought between clinical symptoms and DISH using the following grading system: 1, DISH at T3-T10, 2, DISH at both T3–10 and C6–T2 and/or T11–L2, and 3, DISH beyond the C5 and/or L3 levels. Results: DISH was absent in 132 cases, grade 1 in 23, grade 2 in 65, and grade 3 in 19. There were no significant correlations between DISH grade and clinical scores. However, there was a significant difference in the prevalence of neck pain (but not in back pain or low back pain) among the three grades. Interestingly, DISH localized in the thoracic spine (grade 1) may create overload at the cervical spine and lead to neck pain in patients with cervical OPLL. Conclusion: This study is the first prospective multicenter cross-sectional comparison of subjective outcomes in patients with cervical OPLL according to the presence or absence of DISH. The severity of DISH was partially associated with the prevalence of neck pain.

The patient was an 82-year-old woman with a diagnosis of lumbar radiculopathy due to foraminal stenosis accompanied by ossification of the ligamentum flavum (OLF). Computed tomography scans of the lumbar spine revealed ossification in the capsular portion of the ligamentum flavum around the L2–L3 facet joint. In addition, computed tomography images acquired a few months before the onset of radiculopathy had shown that the ossification site had gradually expanded to include the superior articular process. The patient’s symptoms disappeared immediately after excision of the OLF. Histopathological examination of the resected specimen indicated replacement of degenerated ligamentum flavum with ossified tissue via a gradual endochondral ossification process. It is important to be aware that foraminal stenosis can in rare cases occur due to OLF, even in the lumbar spine.

Objective To visualize neural activity in the brachial plexus using magnetoneurography (MNG). Methods Using a 124- or 132-channel biomagnetometer system with a superconducting quantum interference device, neuromagnetic fields above the clavicle and neck region were recorded in response to electrical stimulation of the median and ulnar nerves in five asymptomatic volunteers (four men and one woman; age, 27–45 years old). Equivalent currents were computationally reconstructed from neuromagnetic fields and visualized as pseudocolor maps. Reconstructed currents at the depolarization site and compound nerve action potentials (CNAPs) at Erb’s point were compared. Results Neuromagnetic fields were recorded in all subjects. The reconstructed equivalent currents propagated into the vertebral foramina, and the main inflow levels differed between the median nerve (C5/C6–C7/T1 vertebral foramen) and the ulnar nerve (C7/T1–T1/T2). The inward current peaks at the depolarization site and CNAPs showed high linear correlation. Conclusions MNG visualizes neural activity in the brachial plexus and can differentiate the conduction pathways after median and ulnar nerve stimulations. In addition, it can visualize not only the leading and trailing components of intra-axonal currents, but also inward currents at the depolarization site. Significance MNG is a novel and promising functional imaging modality for the brachial plexus.

Prospective observational single-center study.To evaluate anterior decompression and fusion (ADF) or posterior surgery (PS) for patients with cervical spondylotic myelopathy (CSM) using the modified K-line (mK-line) and to compare clinical and radiologic outcomes between these 2 techniques.The authors have previously reported that insufficient posterior decompression is often seen after laminoplasty for CSM in patients with preoperative anterior clearance of the spinal cord4 mm on the basis of the mK-line. However, to our knowledge, no study has investigated the role, if any, of the mK-line in surgical decision making for patients with CSM.A total of 87 patients were enrolled who underwent surgery for treatment of CSM between 2011 and 2015 at our hospital and who could be followed up for at least 2 years. ADF was selected as a more favorable procedure than PS in patients with anterior spinal clearance of4 mm on preoperative midsagittal magnetic resonance imaging. On the basis of the Japanese Orthopedic Association (JOA) scoring system for cervical myelopathy, the rate of recovery of the JOA scores at 2 years after surgery was investigated as a clinical outcome to compare these 2 groups.Mean age was 65.1 (±12.9) years in the ADF group (n=26) and 70.5 (±8.6) years in the PS group (n=61). In the PS group, 10 patients underwent posterior decompression with fusion. Mean preoperative and postoperative JOA scores were 10.5 and 14.1 points in the ADF group and 9.8 and 13.1 points in the PS group, respectively, showing no significant difference in recovery rate of JOA score between the ADF (58.9%) and PS (47.1%) groups. However, patients with a minimum interval between the mK-line and the anterior compression factor on the midsagittal image (minimum interval of the spinal cord)4 mm tended to have unsatisfactory outcomes (recovery rate 29.6%) compared with patients with minimum interval of the spinal cord4 mm (53.6%, P=0.07) in the PS group.Preoperative intervention using the mK-line is useful to predict residual cord compression and might homogenize postoperative clinical outcomes in both anterior surgery and PS.

Introduction: Approximately 3% of osteoporotic vertebral fractures develop osteoporotic vertebral collapse (OVC) with neurological deficits, and such patients are recommended to be treated surgically. However, a proximal junctional fracture (PJFr) following surgery for OVC can be a serious concern. Therefore, the aim of this study is to identify the incidence and risk factors of PJFr following fusion surgery for OVC. Methods: This study retrospectively analyzed registry data collected from facilities belonging to the Japan Association of Spine Surgeons with Ambition (JASA) in 2016. We retrospectively analyzed 403 patients who suffered neurological deficits due to OVC below T10 and underwent corrective surgery; only those followed up for ≥2 years were included. Potential risk factors related to the PJFr and their cut-off values were calculated using multivariate logistic regression analysis and receiver operating characteristic (ROC) analysis. Results: Sixty-three patients (15.6%) suffered PJFr during the follow-up (mean 45.7 months). In multivariate analysis, the grade of osteoporosis (grade 2, 3: adjusted odds ratio (aOR) 2.92; p=0.001) and lower instrumented vertebra (LIV) level (sacrum: aOR 6.75; p=0.003) were independent factors. ROC analysis demonstrated that lumbar bone mineral density (BMD) was a predictive factor (area under curve: 0.72, p=0.035) with optimal cut-off value of 0.61 g/cm(2) (sensitivity, 76.5%; specificity, 58.3%), but that of the hip was not (p=0.228). Conclusions: PJFr was found in 16% cases within 4 years after surgery; independent risk factors were severe osteoporosis and extended fusion to the sacrum. The lumbar BMD with cut-off value 0.61 g/cm(2) may potentially predict PJFr. Our findings can help surgeons select perioperative adjuvant therapy, as well as a surgical strategy to prevent PJFr following surgery.

Background: The purpose of this study was to clarify the clinical features of ossification of the posterior longitudinal ligament (OPLL) and extreme ossification at multiple sites. Methods: This prospective study involved patients with a diagnosis of cervical OPLL at 16 institutions in Japan. Patient-reported outcome measures, including responses on the Japanese Orthopaedic Association (JOA) Cervical Myelopathy Evaluation Questionnaire (JOA-CMEQ), JOA Back Pain Evaluation Questionnaire (JOA-BPEQ), and visual analog scale pain score, were collected to investigate clinical status. In each patient, the sum of the levels at which OPLL was located (OP index) was evaluated on whole-spine computed tomography, along with ossification of other spinal ligaments including the anterior longitudinal ligament (OALL), ligament flavum (OLF), supra- and intraspinous ligaments (SSL), and diffuse idiopathic skeletal hyperostosis (DISH). The distribution of OP index values in the study population was investigated, and the clinical and radiologic characteristics of patients in the top 10% were assessed. Results: In total, 236 patients (163 male, 73 female; mean age 63.5 years) were enrolled. Twenty-five patients with OP index ≥ 17 were categorized into a high OP index group and the remainder into a moderate/low OP index group. There were significantly more women in the high OP index group. Patients in the high OP index group also had significantly poorer scores for lower extremity function and quality of life on the JOA-CMEQ and in each domain but not for body pain on the JOA-BPEQ compared with those in the moderate/low OP index group. Patients in the high OP index group had more OALL in the cervical spine and more OLF and SSL in the thoracic spine. The prevalence of DISH was also significantly higher in the high OP index group. In the high OP index group, interestingly, OPLL was likely to be present adjacent to DISH in the cervicothoracic and thoracolumbar spine, especially in men, and often coexisted with DISH in the thoracic spine in women. Conclusion: This prospective cohort registry study is the first to demonstrate the clinical and radiologic features of patients with OPLL and a high OP index. In this study, patients with a high OP index had poorer physical function in the lumbar spine and lower extremities and were also predisposed to extreme ossification of spinal ligaments other than the OPLL.

Background Thoracic ossification of ligamentum flavum (T-OLF), as one of the causes of thoracic myelopathy, is often combined with other spinal disorders. Concurrent lumbar spinal canal stenosis (LCS) is often obscured by symptoms due to T-OLF, leading to difficulty in identifying the origin of these neurological findings. It is common to be misdiagnosed or delayed diagnosis due to the complicated nature. We evaluated the prevalence, distribution, and clinical characteristics of OLF, especially in patients with LCS. Methods The authors performed a retrospective analysis of the outcomes of 61 patients who underwent thoracic surgeries performed for symptomatic T-OLF. In all the patients, whole spine lesions were evaluated preoperatively. We examined the factors related to poor outcomes (the recovery rate of the Japanese Orthopedic Association score for thoracic myelopathy is less than 40%) following OLF surgeries. We compared the clinical outcomes according to whether there was concurrent LCS, and determined the optimal surgical approach. Results The occurrence of T-OLF increased with age. Forty-six cases (75.4%) were considered to be tandem T-OLF and LCS (LCS group). An advanced age, and concurrent LCS were associated with a poor outcome after the surgery. The LCS group significantly included a greater number of elderly, and more light-weighted patients with Modic change in thoracic spine and a greater sagittal vertical axis, resulting in the lower neurological recovery. Additional lumbar surgery (13cases) effectively improved both the T-JOA and L-JOA scores (from 6.5 ± 2.0 points to 8.0 ± 1.8 points, p = 0.0406, and from 14.5 ± 4.7 points to 20.7 ± 2.6 points, p = 0.001, respectively) in OLF patients with LCS. Conclusions T-OLF was highly associated with other spinal disorders. Poor outcomes in T-OLF surgery could be associated with age and concurrent LCS, and an additional surgery for another lumbar lesion significantly improved neurological findings in T-OLF patients.

Background: Thoracic ossification of ligamentum flavum (T-OLF), as one of the causes of thoracic myelopathy, is often combined with other spinal disorders. Concurrent lumbar spinal canal stenosis (LCS) is often obscured by symptoms due to T-OLF, leading to difficulty in identifying the origin of these neurological findings. It is common to be misdiagnosed or delayed diagnosis due to the complicated nature. We evaluated the prevalence, distribution, and clinical characteristics of OLF, especially in patients with LCS.Methods: The authors performed a retrospective analysis of the outcomes of 61 patients who underwent thoracic surgeries performed for symptomatic T-OLF. In all the patients, whole spine lesions were evaluated preoperatively. We examined the factors related to poor outcomes (the recovery rate of the Japanese Orthopedic Association score for thoracic myelopathy is less than 40%) following OLF surgeries. We further compared the clinical outcomes according to whether there was concurrent LCS, and determined the optimal surgical approach.Results: The occurrence of T-OLF increased with age. Forty-six cases (75.4%) were considered to be tandem T-OLF and LCS (LCS group). An advanced age, and concurrent LCS were associated with a poor outcome after the surgery, rather than type of surgical procedure, the local T-OLF size, configuration, the number of OLF lesions, or radiographic cervical stenosis. The LCS group significantly included a greater number of elderly, and more light-weighted patients with Modic change in thoracic spine and a greater sagittal vertical axis, resulting in the lower neurological recovery. Additional lumbar surgery (13cases) effectively improved both the T-JOA and L-JOA scores (from 6.5 ± 2.0 points to 8.0 ± 1.8 points, p=0.0406, and from 14.5 ± 4.7 points to 20.7 ± 2.6 points, p=0.001, respectively) in OLF patients with LCS.Conclusions: T-OLF was highly associated with other spinal disorders. Poor outcomes in T-OLF surgery could be associated with age and concurrent LCS, and an additional surgery for another lumbar lesion significantly improved neurological findings in T-OLF patients.

Background: Thoracic ossification of ligamentum flavum (T-OLF), as one of the causes of thoracic myelopathy, is often combined with other spinal disorders. Concurrent lumbar spinal canal stenosis (LCS) is often abstruse by symptoms due to T-OLF, leading to difficulty in identifying the origin of these neurological findings. It is common to be misdiagnosed or delayed diagnosis due to the complicated nature. We evaluated the prevalence, distribution, and clinical characteristics of OLF, especially in patients with LCS.Methods: The authors performed a retrospective analysis of the outcomes of 61 patients who underwent thoracic surgeries performed for symptomatic T-OLF. In all the patients, whole spine lesions were evaluated preoperatively. We examined the factors related to poor outcomes (the recovery rate of the Japanese Orthopedic Association score for thoracic myelopathy is less than 40%) following OLF surgeries. We further compared the clinical outcomes according to whether there is concurrent LCS, and determined the optimal surgical approach.Results: The prevalence of T-OLF increased in an age-dependent manner. Forty-six cases (75.4%) were considered to be tandem T-OLF and LCS (LCS group). An advanced age, and concurrent LCS were associated with a poor outcome after the surgery, rather than type of surgical procedure, the local T-OLF size, configuration, the number of OLF lesions, or radiographic cervical stenosis. The LCS group significantly included a greater number of elderly, and more light-weighted patients with Modic change in thoracic spine and a greater SVA, resulting in the lower neurological recovery. Additional lumbar surgery (13cases) effectively improved both the T-JOA and L-JOA scores (from 6.5 ± 2.0 points to 8.0 ± 1.8 points, p=0.0406, and from 14.5 ± 4.7 points to 20.7 ± 2.6 points, p=0.001, respectively) in OLF patients with LCS.Conclusions: T-OLF was highly combined with other spinal disorders. Poor outcomes in T-OLF surgery could be associated with age and concurrent LCS, and an additional surgery for another lumbar lesion significantly improved neurological findings in T-OLF patients.

Background Vertebroplasty with posterior spinal fusion (VP + PSF) is one of the most widely accepted surgical techniques for treating osteoporotic vertebral collapse (OVC). Nevertheless, the effect of the extent of fusion on surgical outcomes remains to be established. This study aimed to evaluate the surgical outcomes of short- versus long-segment VP + PSF for OVC with neurological impairment in thoracolumbar spine. Methods We retrospectively collected data from 133 patients (median age, 77 years; 42 men and 91 women) from 27 university hospitals and their affiliated hospitals. We divided patients into two groups: a short-segment fusion group (S group) with 2- or 3-segment fusion (87 patients) and a long-segment fusion group (L group) with 4- through 6-segment fusion (46 patients). Surgical invasion, clinical outcomes, local kyphosis angle (LKA), and complications were evaluated. Results No significant differences between the two groups were observed in terms of neurological recovery, pain scale scores, and complications. Surgical time was shorter and blood loss was less in the S group, whereas LKA at the final follow-up and correction loss were superior in the L group. Conclusion Although less invasiveness and validity of pain and neurological relief are secured by short-segment VP + PSF, surgeons should be cautious regarding correction loss.

Background The optimal treatment of osteoporosis after reconstruction surgery for osteoporotic vertebral fractures (OVF) remains unclear. In this multicentre retrospective study, we investigated the effects of typically used agents for osteoporosis, namely, bisphosphonates (BP) and teriparatide (TP), on surgical results in patients with osteoporotic vertebral fractures. Methods Retrospectively registered data were collected from 27 universities and affiliated hospitals in Japan. We compared the effects of BP vs TP on postoperative mechanical complication rates, implant-related reoperation rates, and clinical outcomes in patients who underwent posterior instrumented fusion for OVF. Data were analysed according to whether the osteoporosis was primary or glucocorticoid-induced. Results A total of 159 patients who underwent posterior instrumented fusion for OVF were included. The overall mechanical complication rate was significantly lower in the TP group than in the BP group (BP vs TP: 73.1% vs 58.2%, p = 0.045). The screw backout rate was significantly lower and the rates of new vertebral fractures and pseudoarthrosis tended to be lower in the TP group than in the BP group. However, there were no significant differences in lumbar functional scores and visual analogue scale pain scores or in implant-related reoperation rates between the two groups. The incidence of pseudoarthrosis was significantly higher in patients with glucocorticoid-induced osteoporosis (GIOP) than in those with primary osteoporosis; however, the pseudoarthrosis rate was reduced by using TP. The use of TP also tended to reduce the overall mechanical complication rate in both primary osteoporosis and GIOP. Conclusions The overall mechanical complication rate was lower in patients who received TP than in those who received a BP postoperatively, regardless of type of osteoporosis. The incidence of pseudoarthrosis was significantly higher in patients with GIOP, but the use of TP reduced the rate of pseudoarthrosis in GIOP patients. The use of TP was effective to reduce postoperative complications for OVF patients treated with posterior fusion.

Several postoperative problems have been reported in conventional cervical laminoplasty (C-LAMP), such as loss of cervical curvature, sagittal imbalance, and loss of range of motion (ROM). Selective laminectomy (S-LAM) is a less invasive procedure that may prevent the problems associated with conventional C-LAMP. In this study, the authors prospectively compared neurological outcomes and radiological parameters in C-LAMP and S-LAM for the treatment of cervical spondylotic myelopathy. Fifty-three patients were enrolled, with 25 patients receiving conventional double-door C-LAMP and 28 patients receiving S-LAM. Measured outcomes included operative time, intraoperative blood loss, Japanese Orthopaedic Association score for neurological recovery, cervical sagittal alignment at C2-7, cervical sagittal vertical axis from occiput to C7, C7 slope, and cervical ROM at C2-7. No difference was found in operative time, whereas intraoperative blood loss was significantly less in the S-LAM group ( P P P P Orthopedics . 2020;43(4);e311–e315.]

Background Decompression through an anterior approach is theoretically effective for the surgical treatment of cervical spondylotic amyotrophy (CSA), because the pathology usually locates at the anterior side. However, most previous studies investigated posterior surgery or a mix of anterior surgery and posterior surgery in their investigation. Only a few small case series have investigated the surgical outcomes of anterior decompression and fusion (ADF). Therefore, we conducted a multicenter retrospective study that included patients who underwent ADF for proximal-type CSA. Methods We analyzed the outcomes of 77 consecutive spinal surgeries performed on proximal-type CSA patients who underwent ADF. Preoperative and postoperative manual muscle tests (MMT) and the patients’ backgrounds, radiological findings, and complications were reviewed. We divided the cases into two groups, good-outcome group (MMT improvement ≧ 2 or improved to MMT 5) and poor-outcome group (others) and evaluated the prognostic factors for outcomes. Results Of the 77 patients, 48 (62%) showed good neurological outcome. Multiple compressive lesions at anterior horn (AH) and/or ventral nerve roots (VNRs) were detected in 66 patients (85.7%) on the magnetic resonance images. The patients with a single compressive lesion at VNR or AH tended to show good neurological recovery when compare to those with multiple lesions. Age and duration of symptoms were related to the poor outcome in univariate analysis. Duration of symptoms was an independent factor associated with postoperative neurological outcome. The cut-off value for poor outcome was 7.0 months for the symptom duration (sensitivity: 79%, specificity: 54%, area under the curve: 0.69). Conclusions Patients with proximal-CSA were more likely to have multiple compressive lesions at an AH and/or a VNR. The prognostic factor for poor neurological outcome was duration of symptoms of ≥7 months.

Additional file 1. Modified Japanese Orthopaedic Association (JOA) scoring system for lumbar function.

Introduction Patients treated with revision surgery after lumbar decompression with fusion typically have persistent low back pain and lower extremity numbness compared with patients treated with only primary surgery. No well-designed study has investigated the persistence and degree of pain after revision surgery following instrumented operation. The purpose of this study is to compare residual pain among patients who underwent reoperation and those who underwent only primary surgery for lumbar degenerative disorder using patient-based evaluation. Methods We reviewed 350 consecutive patients (143 men, 207 women, mean age 63 years) treated with primary lumbar instrumented surgery between October 2010 and February 2014 at our institution and followed up for ≥2 years postoperatively. Patients were categorized into three groups based on number of levels fused: 1-segment, 2-segment, and ≥3-segment fusion (1F, 2F, and ≥3F groups, respectively). We used the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and visual analog scales (VASs) for low back pain and lower extremity pain to evaluate pain intensity pre- and postoperatively. Results Salvage surgery for late-phase complications was required in 5 cases (2.4%), 6 cases (11.3%), and 11 cases (12.1%) in the 1F, 2F, and ≥3F groups, respectively. In the 1F and 2F groups, patients treated with revision surgery had unsatisfactory improvement in the pain domain of JOABPEQ and VASs for low back pain and lower extremity pain compared with patients with only primary short fusion surgery. The ≥3F group showed no significant differences between patients who underwent reoperation and those who underwent only primary surgery. Conclusion Low back pain and lower extremity pain often persist after revision surgery in patients treated with short fusion (≤2-segment) operation. We need to follow pain states in such patients.

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.

Study design Retrospective observational study. Objective We investigated whether bone turnover markers could be a useful indicator for prediction of nonunion. Summary of background data Nonunion is a major complication of lumbar spinal fusion surgery. The involvement of bone turnover in the process of bony union in spinal fusion surgery is, however, poorly understood. Methods Of the 74 patients analyzed, 13 were diagnosed with nonunion. We evaluated the significance of the following risk factors: age, sex, number of fused segments, serum levels of total alkaline phosphatase, procollagen type 1 amino-terminal propeptide (P1NP), tartrate-resistant acid phosphatase 5b (TRACP-5b), and albumin, and history of diabetes mellitus, cigarette smoking, or alcohol use. We also defined the bone turnover ratio (BTR) as a value that equals serum TRACP-5b concentration divided by serum P1NP concentration to evaluate patients' individual bone turnover balance and investigated the significance of BTR as a risk factor. Results Univariate analysis showed that older age, malnutrition, and lower P1NP are risk factors for nonunion. Stepwise logistic regression analysis revealed that in the presence of lower P1NP, higher TRACP-5b becomes a risk factor. Furthermore, we identified BTR as the most significant risk factor for nonunion. The optimum cut-off value of BTR by receiver-operating characteristic curve was 11.74. Conclusion These findings show a relation between bone turnover and nonunion after spinal fusion surgery. The measurement of bone turnover markers could potentially be used to predict nonunion after spinal fusion surgery. Level of evidence 4.

Ossification of the posterior longitudinal ligament (OPLL) is a progressive disease. The bridging of ossified lesions to the vertebral body gradually increases, thereby decreasing the mobility of the cervical spine; thus, cervical spine function may decrease over time. However, cervical spine function in patients with cervical OPLL has not been evaluated in large prospective studies. Therefore, we conducted a prospective multicenter study to clarify whether ossification spread can influence cervical spine function and quality of life (QOL) in patients with cervical OPLL. In total, 238 patients (162 men, 76 women; mean age, 63.9 years) were enrolled from 16 institutions. Each patient underwent whole spine computed tomography and was evaluated cervical spine function and QOL using the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ). In the multivariate regression analysis, a higher neck VAS score and a larger number of bridge formations of OPLL in the whole spine were significant predictors of adverse outcomes related to cervical spine function. This is the first prospective multicenter study to reveal the impact of ossification spread on cervical spine function. These findings are important to understand the natural course of OPLL and can serve as controls when evaluating postoperative cervical spine function.

This study sought to evaluate the facilitation effect of repetitive multi-train transcranial electrical stimulation (mt-TES) at 2 repetition rates on transcranial electrical motor evoked potential (Tc-MEP) monitoring during spinal surgery, and to assess the induction rate in patients with impaired motor function from a compromised spinal cord or spinal nerve. We studied 32 consecutive patients with impaired motor function undergoing cervical or thoracic spinal surgery (470 muscles). A series of 10 TESs with 5 pulse trains were preoperatively delivered at 2 repetition rates (1 and 5 Hz). All peak-topeak amplitudes of the MEPs of the upper and lower extremity muscles elicited by the 10 TESs were measured. The induction rates of the lower extremity muscles were also assessed with muscle and preoperative lower extremity motor function scores. In each of the muscles, MEP amplitudes were augmented by about 2-3 times at 1 Hz and 5-6 times at 5 Hz. Under the 5-Hz condition, all limb muscles showed significant amplification. Also, in all preoperative motor function score groups, the amplitudes and induction rates of the lower extremity muscles were significantly increased. Moreover, the facilitation effects tended to peak in the last half of the series of 10 TESs. In all score groups of patients with preoperative neurological deficits, repetitive mt-TES delivered at a frequency of 5 Hz markedly facilitated the MEPs of all limb muscles and increased the induction rate. We recommend this method to improve the reliability of intraoperative monitoring during spinal surgery.

Diagnosis of nervous system disease is greatly aided by functional assessments and imaging techniques that localize neural activity abnormalities. Electrophysiological methods are helpful but often insufficient to locate neural lesions precisely. One proposed noninvasive alternative is magnetoneurography (MNG); we have developed MNG of the spinal cord (magnetospinography, MSG). Using a 120-channel superconducting quantum interference device biomagnetometer system in a magnetically shielded room, cervical spinal cord evoked magnetic fields (SCEFs) were recorded after stimulation of the lower thoracic cord in healthy subjects and a patient with cervical spondylotic myelopathy and after median nerve stimulation in healthy subjects. Electrophysiological activities in the spinal cord were reconstructed from SCEFs and visualized by a spatial filter, a recursive null-steering beamformer. Here, we show for the first time that MSG with high spatial and temporal resolution can be used to map electrophysiological activities in the cervical spinal cord and spinal nerve.

Rationale: The meningovertebral ligaments are a group of tissues that connect the dura and the vertebral bone. Abnormal fibrous ligaments in the canal space, which are essentially different from these ligaments, have been identified and their presence very rarely results in spinal disorder. Patient concerns: A 20-year-old Mongolian woman had developed persistent headache at 15 years of age. She then became unable to run fast when she was 19 years old and had progressively declining ability to move. She complained of back pain and unstable gait 6 months prior to presentation. Physical examination revealed exaggerated deep tendon reflexes in the lower extremities and decreased proximal leg muscle strength bilaterally. Diagnoses: Magnetic resonance imaging (MRI) revealed abnormal bands compressing the spinal cord at the T10/11 level, with large epidural lipomatosis dorsal to the dural tube. Intervention: To decompress the cord, posterior laminectomy for T3-L3 and removal of the heterotopic ligaments were performed with T8-L1 posterior fusion. Outcomes: Sufficient decompression of the cord was noted on postoperative MRI at the affected segments. The patient could subsequently walk without a cane and headache resolved immediately after the operation. Lessons: The presence of an aberrant epidural band is a rare pathologic state that often coexists with a surrounding lipomatosis and can lead to spinal cord compression. Removal of the band is a promising treatment for myelopathy caused by the compressive lesion.

Study design Retrospective observational study. Objective To analyze a large consecutive cohort of patients who had undergone spinal instrumentation surgery, to characterize a patient population with surgical site infections (SSI), and to identify preoperative risk factors associated with SSI. Summary of background data Malnutrition is a risk factor for SSI in many health conditions; however, the evidence connecting preoperative malnutrition with SSI in spinal instrumentation surgery is limited because of the small number of retrospective studies. While the modified Glasgow prognostic score (mGPS), C-Reactive protein (CRP)-albumin ratio (CAR), controlling nutritional status index (CONUT), prognostic nutritional index (PNI), platelet-lymphocyte ratio (PLR), and neutrophil-lymphocyte ratio (NLR) are established methods for evaluating nutritious status, little has been reported on the predictive value of these indicators with respect to postoperative spinal infection. Methods We retrospectively investigated 384 patients who underwent spinal instrumentation surgery. We evaluated the significance of risk factors, including mGPS, CAR, CONUT, PNI, PLR, and NLR. We then performed stepwise logistic regression analysis to analyze the concurrent effects of various factors on the prevalence of SSI. Results Of the 384 patients analyzed, 14 were diagnosed with SSIs. Univariate analysis showed that preoperative BMI, lymphocyte count, albumin, erythrocyte sedimentation rate, CRP, CONUT, mGPS, CAR, and PNI were risk factors for SSI. Stepwise logistic regression analysis revealed that higher mGPS and lower BMI before surgery were independent risk factors for SSI. A receiver operating characteristic curve showed that the cut-off values of mGPS and BMI were 1 and 20.39, respectively. Conclusion The risk factors for SSI after spinal instrumentation surgery were mGPS more than or equal to 1 and BMI less than or equal to 20.39 kg/m. These findings could help to identify patients at higher risk of SSI after spinal instrumentation surgery. Level of evidence 4.

There have been few reports on the incidence and risk factors of the complications after spinal fixation surgery for osteoporotic vertebral collapse (OVC) with neurological deficits. This study aimed to identify the incidence and risk factors of the complications after OVC surgery.In this retrospective multicenter study, a total of 403 patients (314 women and 89 men; mean age 73.8 years) who underwent spinal fixation surgery for OVC with neurological deficits between 2005 and 2014 were enrolled. Data on patient demographics were collected, including age, sex, body mass index, smoking, steroid use, medical comorbidities, and surgical procedures. All postoperative complications that occurred within 6 weeks were recorded. Patients were classified into two groups, namely, complication group and no complication group, and risk factors for postoperative complications were investigated by univariate and multivariate analyses.Postoperative complications occurred in 57 patients (14.1%), and the most common complication was delirium (5.7%). In the univariate analysis, the complication group was found to be older (p = 0.039) and predominantly male (p = 0.049), with higher occurrence rate of liver disease (p = 0.001) and Parkinson's disease (p = 0.039) compared with the no-complication group. In the multivariate analysis, the significant independent risk factors were age (p = 0.021; odds ratio [OR] 1.051, 95% confidence interval [CI] 1.007-1.097), liver disease (p 0.001; OR 8.993, 95% CI 2.882-28.065), and Parkinson's disease (p = 0.009; OR 3.636, 95% CI 1.378-9.599).Complications after spinal fixation surgery for OVC with neurological deficits occurred in 14.1%. Age, liver disease, and Parkinson's disease were demonstrated to be independent risk factors for postoperative complications.

Background To date, there have been little published data on surgical outcomes for patients with PD with thoracolumbar OVF. We conducted a retrospective multicenter study of registry data to investigate the outcomes of fusion surgery for patients with Parkinson’s disease (PD) with osteoporotic vertebral fracture (OVF) in the thoracolumbar junction. Methods Retrospectively registered data were collected from 27 universities and their affiliated hospitals in Japan. In total, 26 patients with PD (mean age, 76 years; 3 men and 23 women) with thoracolumbar OVF who underwent spinal fusion with a minimum of 2 years of follow-up were included (PD group). Surgical invasion, perioperative complications, radiographic sagittal alignment, mechanical failure (MF) related to instrumentation, and clinical outcomes were evaluated. A control group of 296 non-PD patients (non-PD group) matched for age, sex, distribution of surgical procedures, number of fused segments, and follow-up period were used for comparison. Results The PD group showed higher rates of perioperative complications (p

Distal-type cervical spondylotic amyotrophy (CSA) is a rare form of cervical spondylosis that causes muscle weakness of upper extremities. The pathophysiology and appropriate surgical method for the treatment of CSA are still controversial. We investigated clinical outcomes in surgically treated distal-type CSA. The authors executed an analysis of the outcomes of 43 consecutive spinal surgeries performed in distal-type CSA patients. The duration of symptoms, perioperative manual muscle test (MMT) results, radiological findings, and perioperative complications were reviewed. We compared surgical outcomes between different approaches and examined the factors related to poor outcomes (MMT improvement ≤ 0) after surgery. The pathophysiology of CSA was mostly caused by a combination of multiple lesions in the anterior horn and/or nerve root. Nineteen of 29 patients (65.5%) who received anterior approach methods were included in the good outcome group (MMT improvement ≥ 1), whereas 7 of 14 patients (50.0%) in the posterior group were classified as good. In the anterior group, the mean MMT grade significantly improved from 2.6 to 3.4 (p = 0.0035) despite the higher rate of complications. The duration of symptoms was substantially associated with poor outcomes. The MMT grade significantly improved from 2.2 to 3.2 (p = 0.0118) in the

A retrospective analysis of prospectively collected data of 179 consecutive patients who underwent intraoperative neurophysiological monitoring during posterior cervical spine surgery for compression myelopathy.To evaluate preoperative factors in patients with deteriorating spinal cord function due to flexion of the neck during posterior cervical spine surgery by observing changes in waveforms on intraoperative monitoring.We encountered several cases of intraoperative monitoring warning alerts because of neck flexion during posterior cervical spine surgery. We investigated the incidence rate and intraoperative predictors of deteriorating spinal cord function caused by neck flexion based on waveform changes.Subjects were 179 patients who underwent posterior cervical decompression for spinal cord compression. When warning alarms were set off by amplitude changes in the period between skin incision and exposure of the lamina, the neck position was changed from flexion to neutral, and patients whose electrical potentials recovered following cervical repositioning were placed in the flexion-induced potential reduction group. We then analyzed and extracted risk factors for flexion-induced reduction in electrical potentials.In total, 156 patients were analyzed in this study. Monitoring alarms went off intraoperatively for 7 patients (4.5%) at the time of posterior cervical spine exposure. With regard to the most compressed level, the occupancy ratio of the anterior compression component, the kyphotic angle in flexion, and range of motion in the neutral position to flexion were significantly associated with flexion-induced reduction in electrical potentials. Furthermore, logistic regression analysis extracted the occupancy ratio of the anterior compression component at the most compressed level and the kyphotic angle of the most compressed level in flexion.Our findings suggest that a large anterior compression component and large kyphotic angle in neck flexion at the most compressed level are risk factors for intraoperative spinal cord injury during posterior cervical spine surgery.