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A prospective multicenter observational study.The aim was to investigate the validity of transcranial motor-evoked potentials (Tc-MEP) in cervical spine surgery and identify factors associated with positive predictive value when Tc-MEP alerts are occurred.The sensitivity and specificity of Tc-MEP for detecting motor paralysis are high; however, false-positives sometimes occur.The authors examined Tc-MEP in 2476 cases of cervical spine surgeries and compared patient backgrounds, type of spinal disorders, preoperative motor status, surgical factors, and the types of Tc-MEP alerts. Tc-MEP alerts were defined as an amplitude reduction of more than 70% from the control waveform. Tc-MEP results were classified into two groups: false-positive and true-positive, and items that showed significant differences were extracted by univariate analysis and detected by multivariate analysis.Overall sensitivity was 66% (segmental paralysis: 33% and lower limb paralysis: 95.8%) and specificity was 91.5%. Tc-MEP outcomes were 33 true-positives and 233 false-positives. Positive predictive value of general spine surgery was significantly higher in cases with a severe motor status than in a nonsevere motor status (19.5% vs . 6.7%, P =0.02), but not different in high-risk spine surgery (20.8% vs . 19.4%). However, rescue rates did not significantly differ regardless of motor status (48% vs . 50%). In a multivariate logistic analysis, a preoperative severe motor status [ P =0.041, odds ratio (OR): 2.46, 95% confidence interval (95% CI): 1.03-5.86] and Tc-MEP alerts during intradural tumor resection ( P0.001, OR: 7.44, 95% CI: 2.64-20.96) associated with true-positives, while Tc-MEP alerts that could not be identified with surgical maneuvers ( P =0.011, OR: 0.23, 95% CI: 0.073-0.71) were associated with false-positives.The utility of Tc-MEP in patients with a preoperative severe motor status was enhanced, even in those without high-risk spine surgery. Regardless of the motor status, appropriate interventions following Tc-MEP alerts may prevent postoperative paralysis.

A prospective, multicenter study.This study clarified the uses and limitations of transcranial motor-evoked potentials (Tc-MEPs) for nerve root monitoring during adult spinal deformity (ASD) surgeries.Whether Tc-MEPs can detect nerve root injuries (NRIs) in ASD surgeries remains controversial.We prospectively analyzed neuromonitoring data from 14 institutions between 2017 and 2020. The subjects were ASD patients surgically treated with posterior corrective fusion using multichannel Tc-MEPs. An alert was defined as a decrease of ≥70% in the Tc-MEP's waveform amplitude from baseline, and NRI was considered as meeting the focal Tc-MEP alerts shortly following surgical procedures with postoperative nerve root symptoms in the selected muscles.A total of 311 patients with ASD (262 women and 49 men) and a mean age of 65.5 years were analyzed. Tc-MEP results revealed 47 cases (15.1%) of alerts, including 25 alerts after 10 deformity corrections, six three-column osteotomies, four interbody fusions, three pedicle screw placements or two decompressions, and 22 alerts regardless of surgical maneuvers. Postoperatively, 14 patients (4.5%) had neurological deterioration considered to be all NRI, 11 true positives, and three false negatives (FN). Two FN did not reach a 70% loss of baseline (46% and 65% loss of baseline) and one was not monitored at target muscles. Multivariate logistic regression analysis revealed that risk factors of NRI were preexisting motor weakness ( P0.001, odds ratio=10.41) and three-column osteotomies ( P =0.008, odds ratio=7.397).Nerve root injuries in our ASD cohort were partially predictable using multichannel Tc-MEPs with a 70% decrease in amplitude as an alarm threshold. We propose that future research should evaluate the efficacy of an idealized warning threshold (e.g., 50%) and a more detailed evoked muscle selection, in reducing false negatives.

A prospective multicenter study.This study aims to evaluate patient-reported outcomes using the Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) and clarify clinical factors that affect the therapeutic effects for patients with cervical ossification of the posterior longitudinal ligament (OPLL).Although previous studies identified factors that affected the surgical outcomes, their assessment was mainly based on the Japanese Orthopedic Association score, which only includes neurological function. Investigating this pathology through multiple functions and quality of life (QOL) is pivotal to understanding the comprehensive clinical pictures of the cervical OPLL and its therapeutic outcomes.This study was performed by the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament. A total of 478 patients with myelopathy caused by cervical OPLL from 28 institutions were prospectively registered from 2014 to 2017 and followed up for 2 years. Of the patients, 168 received laminoplasties and fully completed questionnaires. Demographic information, imaging findings, and clinical outcomes were collected. Patients were grouped according to effective or ineffective surgical outcomes as defined by the JOACMEQ using logistic regression analyses.Laminoplasty resulted in functional improvement in the cervical spine and upper extremity around 40% of the patients, while QOL showed only 21.4% ( P0.01). Multivariable analyses revealed that younger age and a postoperative decrease in arm or hand pain were correlated with significantly improved function of the upper extremities. A reduction in lower limb pain favorably affected the postoperative lower extremity function. A postoperative reduction in upper extremity pain enhanced the QOL recovery.Surgeons should recognize the diversity of surgical outcomes after laminoplasty and understand the necessity of pain management even after the surgery to enhance bodily functions and QOL in patients with cervical OPLL.

STUDY DESIGN A cross-sectional study. OBJECTIVE The present study aimed to investigate the prevalence of neuropathic pain (NeP) in subjects suffering from neck and shoulder pain (NSP) to reveal the impact of NeP on the health-related quality of life (HRQOL) in middle-aged and elderly people with NSP in a health checkup. SUMMARY OF BACKGROUND DATA No previous studies have established the relationship between NSP and NeP as potential risk factors contributing to a decreased quality of life (QOL) in the general population. METHODS The present study involved 203 participants (men: 84, women: 119; mean age: 63.3 years). For each subject, anthropometric measurements, physical function examinations, and blood testing were performed. A cut-off score of ≥0 on the short-form Spine painDETECT questionnaire (SF-SPDQ) defined the presence of NeP. Subsequently, the NSP (+) subjects were divided into two sub-groups: the NeP (+) and NeP (-) groups. For the assessment of QOL, the Medical Outcomes Study 36-item short-form health survey (SF-36) and the EuroQol 5 dimension 5 level version (EQ-5D-5L) tool were used. RESULTS The study included 100 NSP (+) and 103 NSP (-) subjects. Among the NSP (+) subjects, 46 and 54 subjects were found to be NeP (+) and NeP (-), respectively. For SF-36, the multivariate regression analysis revealed that the prevalence of NeP was associated with a lower physical QOL (odds ratio [OR] 3.56) and lower mental QOL (OR 4.04). Similarly, the NeP prevalence was found to be the predictor for low QOL scores in EQ-5D-5L (EQ-5D-5L index value

Study design A prospective, multicenter study. Objective To evaluate the usefulness of transcranial motor-evoked potentials (Tc-MEPs) during supine-to-prone position change for thoracic ossification of the posterior longitudinal ligament (T-OPLL). Summary of background data Supine-to-prone position change might be a risk of spinal cord injury in posterior decompression and fusion surgeries for T-OPLL. Methods The subjects were 145 patients with T-OPLL surgically treated with posterior decompression and fusion using Tc-MEPs in 14 institutes. Tc-MEPs were monitored before surgery from supine-to-prone position and intraoperatively in 7 institutes and only intraoperatively in the other 7 institutes because of disapproval of the anesthesia department. In cases of Tc-MEP alert after position change, we adjusted the cervicothoracic posture. When the MEP did not recover, we reverted the position to supine and monitored the Tc-MEPs in supine position. Results There were 83 and 62 patients with/without Tc-MEP before position change to prone (group A and B). The true-positive rate was lower in group A than group B, but without statistical significance (8.4% vs 16.1%, p = 0.12). In group A, 5 patients who had Tc-MEP alert during supine-to-prone position change were all female and had larger body mass index values and upper thoracic lesions. Among the patients, 3 underwent surgeries after cervicothoracic alignment adjustment, and 2 had postponed operations to 1 week later with halo-vest fixation because of repeated Tc-MEP alerts during position change to prone. The Tc-MEP alert at exposure was statistically more frequent in group B than in group A (p = 0.033). Conclusion Tc-MEP alert during position change is an important sign of spinal cord injury due to alignment change at the upper thoracic spine. Tc-MEP monitoring before supine-to-prone position change was necessary to prevent spinal cord injury in surgeries for T-OPLL.Level of Evidence: 4.

Study design A prospective multicenter observational study. Objective To elucidate the efficacy of transcranial motor-evoked potentials (Tc(E)-MEPs) in degenerative cervical myelopathy (DCM) surgery by comparing cervical spondylotic myelopathy (CSM) to cervical ossification of the posterior longitudinal ligament (OPLL) and investigate the timing of Tc(E)-MEPs alerts and types of interventions affecting surgical outcomes. Summary of background data Although CSM and OPLL are the most commonly encountered diseases of DCM, the benefits of Tc(E)-MEPs for DCM remain unclear and comparisons of these two diseases have not yet been conducted. Methods We examined the results of Tc(E)-MEPs from 1176 DCM cases (840 CSM /336 OPLL) and compared patients background by disease, preoperative motor deficits, and the type of surgical procedure. We also assessed the efficacy of interventions based on Tc(E)-MEPs alerts. Tc(E)-MEPs alerts were defined as an amplitude reduction of more than 70% below the control waveform. Rescue cases were defined as those in which waveform recovery was achieved after interventions in response to alerts and no postoperative paralysis. Results Overall sensitivity was 57.1%, and sensitivity was higher with OPLL (71.4%) than with CSM (42.9%). The sensitivity of acute onset segmental palsy including C5 palsy was 40% (OPLL/CSM: 66.7%/0%) whereas that of lower limb palsy was 100%. The most common timing of Tc(E)-MEPs alerts was during decompression (63.16%), followed by screw insertion (15.79%). The overall rescue rate was 57.9% (OPLL/CSM: 58.3%/57.1%). Conclusion Since Tc(E)-MEPs are excellent for detecting long tract injuries, surgeons need to consider appropriate interventions in response to alerts. The detection of acute onset segmental palsy by Tc(E)-MEPs was partially possible with OPLL, but may still be difficult with CSM. The rescue rate was higher than 50% and appropriate interventions may have prevented postoperative neurological complications.Level of Evidence: 3.

Study design A retrospective analysis of prospectively collected data. Objective This study aimed to create a prognostic model for surgical outcomes in patients with cervical ossification of the posterior longitudinal ligament (OPLL) using machine learning (ML). Summary of background data Determining surgical outcomes helps surgeons provide prognostic information to patients and manage their expectations. ML is a mathematical model that finds patterns from a large sample of data and makes predictions outperforming traditional statistical methods. Methods Out of 478 patients, 397 and 370 patients had complete follow-up information at 1 and 2 year respectively and were included in the analysis. A minimal clinically important difference (MCID) was defined as an acquired Japanese Orthopaedic Association (JOA) score of 2.5 points or more, after which a ML model that predicts whether MCID can be achieved 1 and 2 years after surgery was created. Patient background, clinical symptoms, and imaging findings were used as variables for analysis. The ML model was created using LightGBM, XGBoost, random forest, and logistic regression, after which the accuracy and area under the receiver operating characteristic curve (AUC) were calculated. Results The mean JOA score was 10.3 preoperatively, 13.4 at 1 year after surgery, and 13.5 at 2 years after surgery. XGBoost showed the highest AUC (0.72) and high accuracy (67.8) for predicting MCID at 1 year, while random forest had the highest AUC (0.75) and accuracy (69.6) for predicting MCID at 2 years. Among the included features, total preoperative JOA score, duration of symptoms, body weight, sensory function of the lower extremity sub-score of the JOA, and age were identified as having the most significance in most of ML models. Conclusion Constructing a prognostic ML model for surgical outcomes in patients with OPLL is feasible, suggesting the potential application of ML for predictive models of spinal surgery.Level of Evidence: 4.

STUDY DESIGN Prospective multicenter study. OBJECTIVE To examine transcranial motor evoked potential (Tc-MEP) waveforms in intraoperative neurophysiological monitoring (IONM) in surgery for intradural extramedullary (IDEM) tumors, focused on the characteristics for cervical, thoracic and conus lesions. SUMMARY OF BACKGROUND DATA IDEM tumors are normally curable after resection, but neurological deterioration may occur after surgery. IONM using Tc-MEPs during surgery is important for timely detection of possible neurological injury. METHODS The subjects were 233 patients with IDEM tumors treated surgically with Tc-MEP monitoring at 9 centers. The alarm threshold was ≥70% waveform deterioration from baseline. A case with a Tc-MEP alert that normalized and had no new motor deficits postoperatively was defined as a rescue case. A deterioration of manual muscle test (MMT) score ≥1 compared to the preoperative value was defined as postoperative worsening of motor status. RESULTS The 233 patients (92 males, 39%) had a mean age of 58.1 ± 18.1 years, and 185 (79%), 46 (20%) and 2 (1%) had schwannoma, meningioma, and neurofibroma. These lesions had cervical (C1-7), thoracic (Th1-10), and conus (Th11-L2) locations in 82 (35%), 96 (41%) and 55 (24%) cases. There were no significant differences in preoperative motor deficit among the lesion levels. Thoracic lesions had a significantly higher rate of poor baseline waveform derivation (0% cervical, 6% thoracic, 0% conus, p

STUDY DESIGN A prospective multicenter study. OBJECTIVE To evaluate and compare the surgical outcomes after open-door (OD) and double-door (DD) laminoplasties in subjects with cervical ossification of the posterior longitudinal ligament (OPLL). SUMMARY OF BACKGROUND DATA Although previous studies compared clinical results after OD and DD laminoplasties, they were performed at a single institution with a relatively small sample size targeting mixed pathologies, including cervical spondylotic myelopathy. METHODS This study was performed by the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament. A total of 478 patients with myelopathy caused by cervical OPLL from 28 institutions were prospectively registered from 2014 to 2017 and followed up for 2 years. Of these, 41 and 164 patients received OD and DD laminoplasties, respectively. Demographic information, medical history, and imaging findings were collected. Clinical outcomes were assessed using the cervical Japanese Orthopaedic Association, Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire, and visual analog scale scores. RESULTS Age, sex, symptom duration, and comorbidities were not significantly different between the groups. Segmental ossification was the most frequent in both the groups. No significant differences in K-line type, canal occupying ratio, C2 to C7 angles, and range of motion were found. Both the procedures reduced the cervical range of motion postoperatively. A comparable frequency of perioperative complications was observed between the groups. The cervical Japanese Orthopaedic Association scores showed a similar improvement at 2 years postopera- tively. The reduction in visual analog scale score for neck pain was favorable in the OD group (P = 0.02), while other pain assessments did not show any significant differences between the groups. The functional outcomes assessed using the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire presented equivalent effective rates. CONCLUSION The results demonstrated almost comparable surgical outcomes between OD and DD laminoplasties. Lamino- plasty is a valuable technique as a therapeutic option for cervical OPLL.Level of Evidence: 2.

STUDY DESIGN Prospective multicenter study. OBJECTIVE The purpose of the study is to examine cases with poor baseline waveform derivation for all muscles in multichannel monitoring of transcranial motor-evoked potentials (Tc-MEPs) in spine surgery. SUMMARY OF BACKGROUND DATA Intraoperative neuromonitoring (IONM) is useful for identifying neurologic deterioration during spinal surgery. Tc-MEPs are widely used for IONM, but some cases have poor waveform derivation, even in multichannel Tc-MEP monitoring. METHODS The subjects were 3625 patients (mean age 60.1 years, range 4-95; 1886 females, 1739 males) who underwent Tc-MEP monitoring during spinal surgery at 16 spine centers between April 2017 and March 2020. Baseline Tc-MEPs were recorded from the deltoid, abductor pollicis brevis, adductor longus, quadriceps femoris, hamstrings, tibialis anterior, gastrocnemius, and abductor hallucis (AH) muscles after surgical exposure of the spine. RESULTS The 3625 cases included cervical, thoracic, and lumbar lesions (50%, 33% and 17%, respectively) and had preoperative motor status of no motor deficit, and motor deficit with manual muscle testing (MMT) ≥3 and MMT

Study design Prospective multicenter study. Objectives The purpose of this study was to characterize a population of patients with degenerative cervical myelopathy (DCM) combined with a history of falling, and to identify the predictors associated with those falls. Summary of background data Falls among patients with DCM are common and can lead to the worsening of neurological symptoms. However, there are no prospective studies that have investigated the risk factors for falls in these patients. Methods We prospectively enrolled patients scheduled for surgery for DCM and evaluated the significance of various preoperative measures for predicting falls. We then examined the correlation between the number of falls and the preoperative factors. Lastly, we performed stepwise logistic regression analysis to assess the concurrent effects of various factors on the occurrence of falls. Results Among the 135 patients analyzed, 64 experienced one or more falls from the time of enrollment to 1 year postoperatively. Univariate analysis showed that the preoperative potassium and albumin levels, handgrip strength, and the Japanese Orthopaedic Association score for the assessment of cervical myelopathy (C-JOA score) were lower and Nurick grade was higher in the fallers group. Serum potassium level, handgrip strength, C-JOA score, Nurick grade, European Quality of Life-5 Dimensions (EQ-5D) score, t1 pelvic angle, and sagittal vertical axis had weak correlations with the number of falls. The fallers group had a lower C-JOA and EQ-5D scores and a lower recovery rate at one year postoperatively. Stepwise multiple logistic regression analysis identified preoperative potassium level and handgrip strength as the independent preoperative predictors for falling. Conclusion We identified preoperative lower serum potassium level and weaker handgrip strength as significant predictors of falls in patients with DCM. Therefore, DCM patients with these risk factors should be cautious about falls and might be candidates for immediate surgical intervention.Level of Evidence: N/A.

Study design Prospective, multicenter, observational study. Objective The aim of this study was to investigate the efficacy of intervention after an alert in intraoperative neurophysiological monitoring (IONM) using transcranial motor-evoked potentials (Tc-MEPs) during surgery for thoracic ossification of the posterior longitudinal ligament (T-OPLL). Summary of background data T-OPLL is commonly treated with posterior decompression and fusion with instrumentation. IONM using Tc-MEPs during surgery reduces the risk of neurological complications. Methods The subjects were 79 patients with a Tc-MEP alert during posterior decompression and fusion surgery for T-OPLL. Preoperative muscle strength (manual muscle testing [MMT]), waveform derivation rate at the start of surgery (baseline), intraoperative waveform changes; and postoperative motor paralysis were examined. A reduction in MMT score of ≥1 on the day after surgery was classified as worsened postoperative motor deficit. An alert was defined as a decrease in Tc-MEP waveform amplitude of ≥70% from baseline. Alerts were recorded at key times during surgery. Results The patients (35 males, 44 females; age 54.6 years) had OPLL at T1-4 (n = 27, 34%), T5-8 (n = 50, 63%), and T9-12 (n = 16, 20%). The preoperative status included sensory deficit (n = 67, 85%), motor deficit (MMT ≤4) (n = 59, 75%), and nonambulatory (n = 26, 33%). At baseline, 76 cases (96%) had a detectable Tc-MEP waveform for at least one muscle, and the abductor hallucis had the highest rate of baseline waveform detection (n = 66, 84%). Tc-MEP alerts occurred during decompression (n = 47, 60%), exposure (n = 13, 16%), rodding (n = 5, 6%), pedicle screw insertion (n = 4, 5%), posture change (n = 4, 5%), dekyphosis (n = 2, 3%), and other procedures (n = 4, 5%). After intraoperative intervention, the rescue rate (no postoperative neurological deficit) was 57% (45/79), and rescue cases had a significantly better preoperative ambulatory status and a significantly higher baseline waveform derivation rate. Conclusion These results show the efficacy of intraoperative intervention following a Tc-MEP alert for prevention of neurological deficit postoperatively.Level of Evidence: 2.

STUDY DESIGN A retrospective study. OBJECTIVE This study aims to establish a new, easy-to-implement global spinal balance (GSB) classification based on individual pelvic anatomical measurements in adult spinal deformity patients, and to validate this classification in terms of patients' quality of life (QOL). SUMMARY OF BACKGROUND DATA Coronal (central sacral vertical line) and sagittal (C7 sagittal vertical axis [C7 SVA]) lines are standard parameters to evaluate GSB. However, these parameters do not consider individual differences in height and physique. Therefore, a new classification to more simply evaluate GSB related to QOL would be a beneficial tool. METHODS This study included 279 patients with adult spinal deformity. The enrollment criteria included age >18 years and scoliosis >30°. GSB was evaluated based on C7 coronal vertical axis and C7 SVA, and was graded with our sagittal (Grades 1-3) and coronal classifications (Grades 1-3), where larger values represented worse GSB. In addition, total global balance classification (Grades 1-3) was also established based on both coronal and sagittal classifications. Patient self-assessment measures of health status were collected using the Scoliosis Research Society patient questionnaire (SRS-22). The relationships between responses to the SRS-22 and GSB were evaluated using partial correlation coefficients, adjusted by age. RESULTS A newly described coronal classification correlated with the preoperative function (P < 0.02), pain (P = 0.001), subtotal (P < 0.001) domains in the SRS-22, whereas a newly described sagittal classification was correlated with the preoperative subtotal domain (P < 0.001). There were also significant correlations between total global balance and the preoperative function (P = 0.03) and subtotal domains (P < 0.001) in the SRS-22. CONCLUSION We present a simple new classification for GSB that strongly correlates with QOL in patients with adult spinal deformity, thereby translating clinical data into meaningful patient outcomes and livelihoods.Level of Evidence: 4.

STUDY DESIGN Prospective study. OBJECTIVE This study aimed to investigate the changes in rib cage deformity in adolescent idiopathic scoliosis (AIS) by comparing the preoperative and postoperative three-dimensional (3D) reconstruction images using simultaneous biplanar radiographic scanning technique (EOS) (EOS Imaging, Paris, France). SUMMARY OF BACKGROUND DATA EOS data are limited for the analyses of preoperative and postoperative rib cage deformity. METHODS A total of 67 Lenke type 1 or 2 AIS patients who underwent surgery (59 females and 8 males) were enrolled in this study. The mean patient age was 14.4 years (range: 11-17 yr). In all patients, posterior corrective fusion was performed with a rod rotation maneuver based on segmental pedicle fixation. Spinal parameters (scoliosis and kyphosis) and rib cage parameters (max thickness, thoracic index (TI), rib hump (RH), surface spinal penetration index (sSPI), end thoracic hump ratio, vertebra-sternum angle, rib vertebral angle difference at the apex, and vertebral lateral decentering), were measured. 3D images were assessed preoperatively and postoperatively at 2-year follow-up. RESULTS Both main thoracic (MT) and proximal thoracic scoliosis were significantly corrected (51° to 15°, 30° to 17°, P

STUDY DESIGN A multicenter retrospective analysis of a prospectively maintained database. OBJECTIVE To examine the characteristics of reoperation for surgical site infection (SSI) after spinal instrumentation surgery, including the efficacy of treatment for SSI and instrumentation retention. SUMMARY OF BACKGROUND DATA Aging of the population and advances in surgical techniques have increased the demand for spinal surgery in elderly patients. Treatment of SSI after this surgery has the main goals of eliminating infection and retaining instrumentation. METHODS The subjects were 16,707 patients who underwent spine surgery with instrumentation in 11 hospitals affiliated with the Nagoya Spine Group from 2004 to 2015. Details of those requiring reoperations for SSI were obtained from surgical records at each hospital. RESULTS There were significant increases in the mean age at the time of surgery (54.6-63.7 years) and the number of instrumentation surgeries (726-1977) from 2004 to 2015. The incidence of reoperation for SSI varied from 0.9% to 1.8%, with a decreasing trend over time. Reoperation for SSI was performed in 206 cases (115 men, 91 women; mean age 63.2 years). The average number of reoperations (1.4 vs. 2.3, P

STUDY DESIGN Retrospective study. OBJECTIVE The purpose of the study was to examine survival after surgery for a metastatic spinal tumor using prognostic factors in the new Katagiri score. SUMMARY OF BACKGROUND DATA Surgery for spinal metastasis can improve quality of life and facilitate treatment of the primary cancer. However, choice of therapy requires identification of prognostic factors for survival, and these may change over time due to treatment advances. The new Katagiri score for the prognosis of skeletal metastasis includes classification of the primary tumor site and the effects of chemotherapy and hormonal therapy. METHODS The subjects were 201 patients (127 males, 74 females) who underwent surgery for spinal metastases at six facilities in the Nagoya Spine Group. Age at surgery, gender, follow-up, metastatic spine level, primary cancer, new Katagiri score (including primary site, visceral metastasis, laboratory data, performance status (PS), and chemotherapy) and survival were obtained from a prospectively maintained database. RESULTS Posterior decompression (n = 29) and posterior decompression and fixation with instrumentation (n = 182) were performed at a mean age of 65.9 (range, 16-85) years. Metastasis was present in the cervical (n = 19, 10%), thoracic (n = 155, 77%), and lumbar (n = 26, 13%) spine, and sacrum (n = 1, 1%). In multivariate analysis, moderate growth (HR 2.95, 95% CI, 1.27-7.89, P

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The objective of this study was to elucidate the rate and causes of reoperation for late neurological deterioration after cervical laminoplasty by comparing cases of cervical spondylotic myelopathy (CSM) with those of ossification of the posterior longitudinal ligament (OPLL). SUMMARY OF BACKGROUND DATA: Although the long-term surgical outcomes of cervical laminoplasty in patients with CSM or OPLL are satisfactory, reoperation is sometimes required for late neurological deterioration after laminoplasty. However, limited information is available about long-term follow-up in such cases. METHODS: This retrospective cohort study included 623 patients who underwent cervical laminoplasty for cervical myelopathy (average follow-up duration, 6.1 [range, 2-15] years). The rate of reoperations for late neurological deterioration (>6 mo after the initial surgery) was investigated. RESULTS: Primary diagnoses were CSM and OPLL in 522 (83.8%) and 101 (16.2%) patients, respectively. During the follow-up period, 10 (1.6%) patients required reoperation: 7 (1.3%) in the CSM group and 3 (3.0%) in the OPLL group. No significant difference was found between the CSM and OPLL groups regarding patients requiring reoperation (P = 0.26). The mean elapsed time between primary surgery and reoperation was 4.7 ±â€Š3.2 and 10.0 ±â€Š5.7 years in the CSM and OPLL groups, respectively. The predicted risk percentages of reoperation at 10 years after primary surgery were 2.9% and 1.0% in the CSM and OPLL group, respectively. The causes of reoperation for CSM were C5 palsy in five, severe radiculopathy in one, and restenosis due to instability after laminoplasty in one case; the cause of reoperation for OPLL was enlargement of ossification in all three cases. CONCLUSION: Although the clinical outcomes of laminoplasty were favorable in most patients, reoperation for late neurological deterioration was required in approximately 1.0% to 3.0% of CSM and OPLL cases within 10 years after laminoplasty. LEVEL OF EVIDENCE: 4.

STUDY DESIGN Prospectively collected, multicenter, nationwide study. OBJECTIVE The aim of this study was to investigate recent surgical methods and trends, outcomes, and perioperative complications in surgery for thoracic ossification of the ligamentum flavum (T-OLF). SUMMARY OF BACKGROUND DATA A prospective multicenter study of surgical complications and risk factors for T-OLF has not been performed, and previous multicenter retrospective studies have lacked details for these items. METHODS Surgical methods, pre- and postoperative thoracic myelopathy (Japanese Orthopedic Association [JOA] score), symptoms, and intraoperative neurophysiological monitoring were investigated prospectively in 223 cases. Differences in these factors between fusion and nonfusion procedures for T-OLF were examined. The minimum follow-up period was 2 years after surgery RESULTS.: The mean JOA score was 6.2 points preoperatively, and 7.9, 8.2, and 8.2 points at 6 months, 1, and 2 year postoperatively, giving mean recovery rates of 35.0%, 40.9%, and 41.4% respectively. Posterior decompression and fusion with instrumentation was performed in 109 cases (48.9%). There were 45 perioperative complications in 30 cases (13.5%), with aggravation of motor disturbance in the lower extremities being most common (4.0%, n = 9). Patients treated with fusion had a significantly higher BMI, rate of gait disturbance, ossification occupation rate of OLF at computed tomography, and intramedullary high intensity area at magnetic resonance imaging (P

Study design A prospective multicenter study. Objective This study aims to investigate the postoperative complications of anterior decompression with fusion (ADF) for the treatment of cervical ossification of the posterior longitudinal ligament (OPLL). Summary of background data Surgical treatment for cervical OPLL has a high risk of various complications. ADF is reported to be effective for cervical OPLL, especially for massive OPLL. However, few studies have focused on the surgical complications of ADF. Methods We prospectively included 102 patients undergoing ADF for severe cervical OPLL with average canal occupying ratio of 49.8%. We evaluated systemic and local complications, neurological complications, and risk factors related to the postoperative complications. Results Frequently observed complications included graft/ implant complications (18.6%), neurological complications (11.8%), and cerebrospinal fluid leak (11.8%). Motor palsy involving only the upper extremity was found in nine patients (8.8%), and other motor palsies involving the lower extremities were found in three patients (2.9%). None of the preoperative factors were significantly associated with the occurrence of neurological palsies, whereas the number of operated levels was a significant factor related to the postoperative graft/implant complications (P = 0.003; odds ratio, 2.112). The incidence of graft/implant complications and related reoperation increased as the number of operated levels increased (especially four levels or more). Most motor palsies were observed immediately after surgery. Of the motor palsies in the bilateral upper extremities and palsies involving the lower extremities, 85.7% showed good recovery, whereas only 40% of unilateral upper extremity motor palsies showed good recovery during the follow-up period. Conclusion In ADF for cervical OPLL, the number of operated levels was a significant factor related to the postoperative complication. Specifically, the incidence of graft/implant complications and reoperation rate increased in ADF with four or more levels.Level of Evidence: 3.

STUDY DESIGN A prospective cohort study. OBJECTIVE This study aimed to investigate the relationship between preoperative cervical sagittal alignment and postoperative kyphosis in patients with cervical spondylotic myelopathy (CSM) and to determine the cut-off angle for predicting the postlaminoplasty kyphosis. SUMMARY OF BACKGROUND DATA There have been several reports describing a cervical kyphosis after laminoplasty. However, there has been no study on the cut-off angle for predicting the postoperative kyphosis in a large series of patients with CSM. METHODS A total of 1025 consecutive patients with CSM (642 men and 383 women; mean age, 64.4 yr; range, 23-93 yrs) who underwent laminoplasty were included. The average follow-up period was 30.0 months. Radiography was performed before the surgery and at final follow-up. The cervical alignment with neutral view was measured by using the Cobb method. An alignment of C2-7 lordotic angle more than 0° was defined as lordosis and C2-7 lordotic angle less than 0° was defined as kyphosis. The incidence of postoperative kyphosis was evaluated on lateral radiographs. RESULTS In all patients, the mean C2-7 alignment in the neutral position was 11.5° lordotic before surgery and 14.2° lordotic at final follow-up. In the patient without preoperative kyphotic alignment, receiver operating characteristic curve of preoperative C2-7 lordotic angle showed 7° as a predictor for the postlaminoplasty kyphosis (area under the curve = 0.75, P

STUDY DESIGN A cross-sectional study. OBJECTIVE The aim of this study was to investigate the lumbar thecal sac dimensions and spinal cord area on magnetic resonance (MR) imaging in healthy volunteers. SUMMARY OF BACKGROUND DATA There are few reports regarding lumbar spine MRI in healthy subjects, and the difference in spinal canal dimensions by age remains unclear. METHODS A total of 629 healthy volunteers were enrolled, including ≥50 males, females, and subjects in each of the 20s to 70s age decades. The anteroposterior and transverse diameters of the thecal sac and axial areas of the thecal sac and spinal cord were measured at the disc levels on T2-weighted axial MR images. The anteroposterior-to-transverse ratio of the thecal sac (APTR) was calculated. RESULTS The thecal sac area from T12/L1 to L4/5 was reduced in older age group, but there was no significant difference in L5/S1. The thecal sac area was significantly reduced in older age group: 89.9%, 86.0%, 84.6%, 80.3% at T12/L1, L1/2, L2/3, and L3/4, respectively, and 79.9% at L4/5 in subjects in their 70 s relative to that in subjects in their 20 s. The APTR was significantly reduced in older age group from T11/12 to L2/L3 in males and at T10/11, L3/4 and from T11/12 to L2/3 in females. Narrow thecal sac areas

STUDY DESIGN Prospective multicenter study. OBJECTIVE The aim of this study was to evaluate transcranial motor evoked potential (Tc-MEP) waveform monitoring in spinal surgery for patients with severe obesity. SUMMARY OF BACKGROUND DATA Spine surgeries in obese patients are associated with increased morbidity and mortality. Intraoperative Tc-MEP monitoring can identify neurologic deterioration during surgery, but has not been examined for obese patients. METHODS The subjects were 3560 patients who underwent Tc-MEP monitoring during spine surgery at 16 centers. Tc-MEPs were recorded from multiple muscles via needle or disc electrodes. A decrease in Tc-MEP amplitude of ≥70% from baseline was used as an alarm during surgery. Preoperative muscle weakness with manual muscle test (MMT) grade ≤4 was defined as a motor deficit, and a reduction of one or more MMT grade postoperatively was defined as deterioration. RESULTS The 3560 patients (1698 males, 47.7%) had a mean age of 60.0 ± 20.3 years. Patients with body mass index >35 kg/m2 (n = 60, 1.7%) were defined as severely obese. Compared with all other patients (controls), the rates of preoperative motor deficit (41.0% vs. 29.6%, P

Study design Prospective multicenter observational study. Objective To evaluate transcranial motor-evoked potentials (Tc-MEPs) baseline characteristics of lower limb muscles and to determine the accuracy of Tc-MEPs monitoring based on preoperative motor status in surgery for high-risk spinal disease. Summary of background data Neurological complications are potentially serious side effects in surgery for high-risk spine disease. Intraoperative spinal neuromonitoring (IONM) using Tc-MEPs waveforms can be used to identify neurologic deterioration, but cases with preoperative motor deficit tend to have poor waveform derivation. Methods IONM was performed using Tc-MEPs for 949 patients in high-risk spinal surgery. A total of 4454 muscles in the lower extremities were chosen for monitoring. The baseline Tc-MEPs was recorded immediately after exposure of the spine. The derivation rate was defined as muscles detected/muscles prepared for monitoring. A preoperative neurological grade was assigned using the manual muscle test (MMT) score. Results The 949 patients (mean age 52.5 ± 23.3 yrs, 409 males [43%]) had cervical, thoracic, thoracolumbar, and lumbar lesions at rates of 32%, 40%, 26%, and 13%, respectively. Preoperative severe motor deficit (MMT ≤3) was present in 105 patients (11%), and thoracic ossification of the posterior longitudinal ligament (OPLL) was the most common disease in these patients. There were 32 patients (3%) with no detectable waveform in any muscles, and these cases had mostly thoracic lesions. Baseline Tc-MEPs responses were obtained from 3653/4454 muscles (82%). Specificity was significantly lower in the severe motor deficit group. Distal muscles had a higher waveform derivation rate, and the abductor hallucis (AH) muscle had the highest derivation rate, including in cases with preoperative severe motor deficit. Conclusion In high-risk spinal surgery, Tc-MEPs collected with multi-channel monitoring had significantly lower specificity in cases with preoperative severe motor deficit. Distal muscles had a higher waveform derivation rate and the AH muscle had the highest rate, regardless of the severity of motor deficit preoperatively.Level of Evidence: 3.

A prospective study. The aim of this study was to characterize the risk factors for poor outcome following cervical laminoplasty in patients with cervical spondylotic myelopathy (CSM). Previous research has identified a variety of potential predictive factors that might affect outcomes after cervical laminoplasty. However, no study till date has assessed the effects of such risk factors, including internal medicine comorbidity and quantitative performance tests, on the outcome of laminoplasty in a large series of patients with CSM. A total of 505 consecutive patients with CSM (311 males; 194 females; mean age, 66.6 years; age range, 41–91 years) who underwent double-door laminoplasty were prospectively included. The average postoperative follow-up period was 26.5 months (range, 12–66 months). We evaluated the recovery rate (RR) on the basis of the Japanese Orthopaedic Association score. Logistic regression analysis was performed to identify the risk factors for poor outcome, which was defined as a postoperative RR of50%. Relationship between outcome and various clinical and imaging predictors was examined. Two hundred ninety-five patients had good outcomes with RR50%, whereas 210 patients had poor outcomes with RR50%. Compared with the good-outcome group, the poor-outcome group had a significantly higher prevalence of diabetes and hypertension and use of anticoagulant/antiplatelet agent and smoking history (P 0.05). Multivariate logistic regression analysis showed independent risks associated with increased age (odds ratio [ORs] = 1.029, 95% confidence interval [CI] = 1.004–1054, P = 0.023). Logistic regression analysis determined that symptom duration of CSM (OR = 1.017, 95% CI = 1.008–1.026, P 0.001) and preoperative 10-second step test (OR = 0.922, 95% CI = 0.865–0.983, P = 0.013) were significant risk factors for poor outcome. These findings suggest that advanced age, long-term CSM symptoms, and lower score of preoperative 10-second step test are risk factors for poor outcome in patients with CSM. Level of Evidence: 2.

Study design A retrospective analysis of magnetic resonance imaging (MRI) was conducted. Objective This study aims to develop an automated system for the detection of spinal schwannoma, by employing deep learning based on object detection from MRI. The performance of the proposed system was verified to compare the performances of spine surgeons. Summary of background data Several MRI scans were conducted for the diagnoses of patients suspected to suffer from spinal diseases. Typically, spinal diseases do not involve tumors on the spinal cord, although a few tumors may exist at the unexpectable level or without symptom by chance. It is difficult to recognize these tumors; in some cases, these tumors may be overlooked. Hence, a deep learning approach based on object detection can minimize the probability of overlooking these tumors. Methods Data from 50 patients with spinal schwannoma who had undergone MRI were retrospectively reviewed. Sagittal T1 and T2 weighted magnetic resonance imaging (T1WI and T2WI) were used in the object detection training and for validation. You Only Look Once version3 was used to develop the object detection system, and its accuracy was calculated. The performance of the proposed system was compared to that of two doctors. Results The accuracies of the proposed object detection based on T1W1, T2W1 and both T1W1 and T2W1 were 80.3%, 91.0%, and 93.5%, respectively. The accuracies of the doctors were 90.2% and 89.3%. Conclusions Automated object detection of spinal schwannoma was achieved. The proposed system yielded a high accuracy that was comparable to that of the doctors. Level of evidence 4.

Study design Prospective multicenter study. Objective The aim of this study was to compare the clinical and radiographic results of laminoplasty (LAMP), anterior decompression with fusion (ADF), and posterior decompression with fusion (PDF) for degenerative cervical myelopathy (DCM). Summary of background data Although ADF, LAMP, and PDF have been performed for DCM, little is known about the difference in impact of these surgical treatments on clinical and radiographic outcomes. Methods We prospectively enrolled patients who were scheduled for surgery for DCM and compared the clinical and radiographic results of ADF, LAMP, and PDF. Results In total, 171 patients completed the 1-year follow-up. Regarding clinical outcomes, the Japanese Orthopedic Association score for the assessment of cervical myelopathy (C-JOA score), European Quality of Life-5 Dimensions (EQ-5D), and Neck Disability Index (NDI) scores improved in all groups postoperatively. However, no significant differences were found in C-JOA, EQ-5D, and NDI scores and recovery rate among the groups. Regarding radiographic parameters, although the operation had no effect on cervical lordosis (CL) and the C2-7 sagittal vertical axis (SVA) in the ADF group, they worsened in the LAMP and PDF group. Although there were no significant differences in any preoperative radiographic parameters within the ADF and LAMP group, CL was significantly lower and the C2-7 SVA was significantly higher in the nonrecovery group within the PDF group. Logistic regression analysis showed that preoperative lower CL was an independent risk factor for poor recovery in the PDF group. Conclusion Although groups showed no significant differences in clinical outcomes, cervical alignment worsened after surgery in the LAMP and PDF groups. Within the PDF group, lower CL was an independent risk factor for poor recovery. Therefore, the indications for PDF in DCM patients with preoperative kyphotic alignment should be carefully considered. Level of evidence 3.

STUDY DESIGN A retrospective review of prospectively collected data. OBJECTIVE The aim of this study was to compare quality of life (QOL) outcomes of posterior lumbar interbody fusion (PLIF) with lateral lumbar interbody fusion (LLIF) using reports from patients obtained at the 2-year postoperative follow-up. SUMMARY OF BACKGROUND DATA Indirect decompression with LLIF is used to treat degenerative lumbar diseases that require neural decompression. However, the difference in improvement in QOL following indirect decompression compared with direct neural decompression using PLIF is unclear. METHODS We enrolled 284 consecutive patients with degenerative lumbar spondylolisthesis in the present study, 203 who underwent PLIF and 81 who underwent LLIF. All patients completed a minimum of 2 years of follow-up. We evaluated the effectiveness of surgery in each category of the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ). RESULTS The results of preoperative JOABPEQ and the severity of thecal sac stenosis were not significantly different between PLIF and LLIF, neither was the rate of perioperative complications (14.8% and 15.4% for the PLIF and LLIF groups, respectively; P = 0.91). The effectiveness at 2 years postoperatively was almost the same for all five domains of the JOABPEQ: 62.6% and 68.9% for pain-related disorders (P = 0.34), 38.3% and 42.7% for lumbar spine dysfunction (P = 0.51), 65.8% and 67.5% for gait disturbance (P = 0.79), 53.5% and 48.8% for social life dysfunction (P = 0.47), and 29.1% and 33.3% for psychological disorders (P = 0.48) following PLIF and LLIF, respectively. Visual analogue scale results for back and lower-limb pain and numbness of the lower limbs were almost the same for both groups. No significant differences were observed in terms of perioperative complications and radiographical outcomes. CONCLUSION Indirect decompression using LLIF improves QOL and radiographical outcomes to a comparable degree as direct decompression via PLIF. LEVEL OF EVIDENCE 4.

A prospective comparative imaging study.This study investigated whether the postoperative classification of and alterations in increased signal intensity (ISI) of the spinal cord reflected the postoperative severity of symptoms and surgical outcomes in cervical spondylotic myelopathy (CSM) patients.Although ISI on performing magnetic resonance imaging (MRI) is observed in CSM patients, alterations in ISI have not been investigated. The association of postoperative ISI with surgical outcomes in CSM patients remains controversial.Totally, 505 consecutive CSM patients (311 males) with a mean age of 66.6 (range, 41-91) years were enrolled. All were treated with laminoplasty and underwent MRI scans: preoperatively and after an average of 26.5 months postoperatively (range 12-66 months). ISI was classified pre- and postoperatively into three groups based on sagittal T2-weighted magnetic resonance images: Grade 0, none; Grade 1, light (obscure); and Grade 2, intense (bright). The patients' pre- and postoperative neurological statuses were evaluated using the Japanese Orthopaedic Association scoring system for cervical myelopathy (JOA score) and other quantifiable tests, including the 10-s grip and release (10-s GR) test and 10-s step test.Preoperatively, 168 patients had Grade 0 ISI, 169 had Grade 1, and 168 had Grade 2; postoperatively, 210 patients had Grade 0 ISI, 94 had Grade 1, and 201 had Grade 2. Patients with postoperative Grade 0 ISI had a better postoperative JOA score, recovery rate, and 10-s GR and 10-s step test scores than those with other grades. The postoperative ISI grade improved in 66 patients (13.1%), worsened in 57 (11.3%), and remained unchanged in 382 (75.6%).Postoperative ISI partially reflects postoperative symptoms and surgical outcomes. Alterations in ISI were observed postoperatively in 123 patients (24.4%) and were not correlated with surgical outcomes.2.

Study design Retrospective study. Objective The goal of the study was to investigate the significance of a change in latency in monitoring of transcranial muscle-action potential (Tc-MsEP) waveforms. Summary of background data Tc-MsEP has become a common approach in spine surgery due to its sensitivity and importance in motor function. Many reports have defined the alarm point of Tc-MsEP waveform as a particular decrease in amplitude, but evaluation of the waveform latency has not attracted as much attention. Methods The subjects were 70 patients who underwent spine surgery using intraoperative Tc-MsEP monitoring. The peak latency was defined as the period from stimulation until the waveform amplitude reached its peak. Relationships with postoperative paralysis were examined separately for latency delays of 5% or more and 10% or more, and in combination with a decrease in amplitude of 70% or more from baseline. Results Acceptable baseline Tc-MsEP responses were obtained from 1225 of 1372 muscles in the extremities (89.3%). Seven of the 70 patients (10%) had postoperative paralysis. A decrease in intraoperative amplitude of 70% or more from baseline occurred in 25 cases, with sensitivity 100%, specificity 71%, false positive rate 29%, and positive predictive value (PPV) 28% for prediction of postoperative paralysis. Compared to baseline, 15 cases had a latency delay of 5% or more, which gave a sensitivity of 100%, specificity of 87%, false positive rate of 0%, and PPV 47%, and 8 cases had a delay of 10% or more, which gave a sensitivity of 86%, specificity of 97%, false positive rate of 3%, and PPV 75%. A combination of a decrease in amplitude of 70% or more from baseline and a delay in latency of 10% or more from baseline had a sensitivity of 86%, specificity of 98%, and a false positive rate of 2%, and PPV 86%. Conclusion Combined use of latency and amplitude could lead to reduction of false positives and increase of PPV in Br(E)-MsEP monitoring. Level of evidence 3.

STUDY DESIGN A prospective cohort study. OBJECTIVE The purpose of this study was to compare the surgical outcomes between nonelderly and elderly patients with cervical spondylotic myelopathy (CSM) and to characterize the preoperative symptoms and postoperative residual symptoms in elderly patients. SUMMARY OF BACKGROUND DATA Age at the time of surgery influences the surgical outcome. However, no report has elucidated residual symptoms after surgery in elderly patients with CSM. We designed a large-scale cohort study examining the surgical outcomes of CSM in elderly patients from a single surgery. METHODS A total of 1025 consecutive patients with CSM (642 men and 383 women; mean age, 64.4 yr; range, 23-93 yr) who underwent laminoplasty were included. Patients were divided into three groups based on age: nonelderly (

STUDY DESIGN A review of accident and incident reports. OBJECTIVE To analyze prevalence, characteristics, and details of perioperative incidents and accidents in patients receiving spine surgery. SUMMARY OF BACKGROUND DATA In our institution, a clinical error that potentially results in an adverse event is usually submitted as an incident or accident report through a web database, to ensure anonymous and blame-free reporting. All reports are analyzed by a medical safety management group. These reports contain valuable data for management of medical safety, but there have been no studies evaluating such data for spine surgery. METHODS A total of 320 incidents and accidents that occurred perioperatively in 172 of 415 spine surgeries were included in the study. Incidents were defined as events that were "problematic, but with no damage to the patient," and accidents as events "with damage to the patient." The details of these events were analyzed. RESULTS There were 278 incidents in 137 surgeries and 42 accidents in 35 surgeries, giving prevalence of 33% (137/415) and 8% (35/415), respectively. The proportion of accidents among all events was significantly higher for doctors than non-doctors [68.0% (17/25) vs. 8.5% (25/295), P

STUDY DESIGN A prospective comparison. OBJECTIVE The purpose of this prospective study was to verify the clinical effectiveness of the 10-s grip and release (G&R) and 10-s step quantitative tests for assessing the severity of cervical spondylotic myelopathy (CSM) and to compare age- and sex-related differences in the results between large cohorts of CSM patients and asymptomatic subjects. SUMMARY OF BACKGROUND DATA To determine the severity of CSM, objective and reproducible means of measuring patient disability are essential. No studies have evaluated differences in quantitative test results between a large series of CSM patients and healthy subjects. METHODS Four hundred fifty-four CSM patients and 818 asymptomatic subjects were included. The Japanese subjects were in their 40s to 70s and were divided according to their age by decade. The 10-s G&R and 10-s step tests were used to quantitatively assess performance. The severity of myelopathy before surgery was evaluated according to a scoring system proposed by the Japanese Orthopaedic Association for cervical myelopathy (JOA score) in the CSM patients. RESULTS In the CSM patients, the 10-s G&R and step test results significantly correlated with the JOA score (P

STUDY DESIGN Prospective randomized controlled study. OBJECTIVES To determine the effect of collar-aided fixation on outcomes after laminoplasty for cervical compressive myelopathy. SUMMARY OF BACKGROUND DATA Patients are often placed in a Philadelphia collar for weeks after cervical laminoplasty. However, the benefit of postoperative collar use remains controversial. We hypothesized that treatment outcomes in postoperative pain in patients without collars would not be inferior to the outcomes in patients using Philadelphia collars for 2 weeks. METHODS This trial analyzed 74 patients (52 males, 22 females, mean age 72.7 years) with cervical compressive myelopathy who had undergone double-door laminoplasty. Before surgery, we randomly assigned patients to the collar-fixation (CF) group (postoperative Philadelphia collar for 2 weeks) or the no-collar (NC) group. The primary outcome was the visual analog scale (VAS) for cervical pain up to 1 year after surgery. Secondary outcomes were Japanese Orthopedics Association score, Short Form 36 score (SF-36), cervical range of motion (ROM), lordotic angle, and complications. RESULTS VAS scores up to 1 year after operation were similar with or without collar fixation (P = 0.487, two-way ANOVA). JOA scores improved significantly in both groups (P = 0.002 in CF, P

STUDY DESIGN Retrospective analysis. OBJECTIVE The goal of this study was to examine the relationship of the proliferation potency based on the MIB-1 index and motor status with features of T2-weighted images (T2WI) and contrast T1-weighted images (T1WI) of spinal schwannoma. SUMMARY OF BACKGROUND DATA Spinal schwannomas account for 55% of spinal tumors, but the relationship of cellular proliferation with MRI findings for spinal schwannoma is unknown. METHODS The subjects were 48 patients (22 males and 26 females) with spinal schwannoma who were classified into three subgroups: iso/homo, high/rim, and hetero/hetero, based on T2WI/contrast T1WI. A retrospective analysis of tumor size and MIB-1 index was performed in the context of these MRI findings. Intraoperative findings and pre- and postoperative motor performance were also examined. RESULTS The average tumor size was 32.4 mm (range 10-130 mm) and the average MIB-1 index was 3.8% (range 1-12). In the three subgroups, there were no significant differences in sex, age, duration of disease, tumor lesion, and dumbbell type. In the hetero/hetero group, the tumor size was significantly greater and the MIB-1 index was significantly higher (both P

Study design Prospective multicenter study. Objective The aim of this study was to study the incidence of nonneurologic adverse events related to transcranial electric stimulation (TES) for intraoperative spinal cord monitoring (IOM) with motor-evoked potentials (MEPs) (Tc(E)- MEPs) and determine the need for safety precautions. Summary of background data Tc(E)-MEPs monitoring requires high-voltage multipulse TES that causes widespread muscle contraction and movement. Improved awareness of TES-induced movement-related adverse events is needed. Methods We analyzed data from 2643 patients who underwent high-risk spinal surgery with intraoperative Tc(E)-MEPs at 11 spinal centers from 2010 to 2016. Information about neurologic and non-neurologic postoperative complications was collected, including type of surgical procedure, operative time, estimated blood loss, and treatment for postoperative adverse events. Results A 70% drop in Tc(E)-MEPs amplitude, which was the alarm criterion to interrupt surgery, predicted postoperative motor deficits with 93.5% sensitivity, 91.0% specificity, a false-positive rate of 8.2%, and a false-negative rate of 0.3%. Non-neurologic adverse events developed in 17 (0.64%) patients and were most commonly because of bite injuries (0.57%), including 11 cases of tongue laceration, two cases of lip laceration, and two cases of tooth breakage. Four (0.15%) tongue lacerations required surgical repair with sutures and two tooth breakages required dental treatment. One patient had hair loss corresponding to the TES site. One patient, who underwent additional IOM with transpharyngeal stimulation, had severe nasal hemorrhage following electrode placement by nasal route, which resolved spontaneously. Non-neurologic adverse events did not significantly affect the accuracy of IOM assessment. Neither operative times nor blood loss significantly influenced the occurrence of adverse events. Conclusion During TES-IOM, both the surgeon and monitoring team must consider the possibility-although rare-of non-neurologic adverse events, particularly bite injuries. Such complications can be minimized by using a soft bite-block and frequently evaluating the intraoral integrity of the anesthetized patient. Level of evidence 4.

MINI: On magnetic resonance imaging, indirect decompression using lateral lumbar interbody fusion and posterior fixation was confirmed immediately after surgery and also continuously progressed after surgery, particularly during the first 6 months. Thecal sac enlargement was also confirmed, and is suspected to be caused by the atrophy of the ligamentum flavum and the disc.A prospective cohort study.The aim of this study was to investigate radiographical changes related to indirect decompression using lateral lumbar interbody fusion (LLIF) with posterior fixation.Indirect lumbar decompression via LLIF is used to treat degenerative lumbar diseases requiring neural decompression. Although evidence suggests that thecal sac enlargement follows shortly after surgery, few studies have described the postoperative changes on MRIs.This study involved 102 patients who underwent indirect decompression at 136 levels, with LLIF and posterior fixation. Magnetic resonance imaging (MRIs) were collected preoperatively and several times postoperatively (over a 2-year period starting immediately after surgery). We then quantified the cross-sectional areas of the thecal sac and ligamentum flavum, as well as the anteroposterior diameter of disc bulging, and qualitatively assessed lumbar spinal stenosis according to a modified version of Schizas' classification [Grades A (mild) to C (severe)]. The Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) was used for the assessment of the clinical symptoms.All changes were observable immediately after surgery, progressed over time, and were significantly different statistically at 2 years after surgery. The thecal sac was significantly larger (189% of preoperative; P 0.0001), while the ligamentum flavum and disc bulge were significantly smaller [58.9% and 67.3% of preoperative (P 0.001), respectively]. The number of patients with grade C (severe) lumbar stenosis also dropped significantly (preoperative, 17.6%; 2 years postoperative, 0%). There were no significant differences in JOABPEQ results at 6 months, 1 year, and 2 years postsurgery.Indirect decompression produces immediate positive results that continue to improve over time. The cross-sectional area of the thecal sac doubled by 2 years after surgery, and the ligamentum flavum cross-sectional area and disc bulging both shrank significantly. At the same time, however, postoperative radiographical improvements do not appear to correlate with clinical symptoms.3.A prospective cohort study. The aim of this study was to investigate radiographical changes related to indirect decompression using lateral lumbar interbody fusion (LLIF) with posterior fixation. Indirect lumbar decompression via LLIF is used to treat degenerative lumbar diseases requiring neural decompression. Although evidence suggests that thecal sac enlargement follows shortly after surgery, few studies have described the postoperative changes on MRIs. This study involved 102 patients who underwent indirect decompression at 136 levels, with LLIF and posterior fixation. Magnetic resonance imaging (MRIs) were collected preoperatively and several times postoperatively (over a 2-year period starting immediately after surgery). We then quantified the cross-sectional areas of the thecal sac and ligamentum flavum, as well as the anteroposterior diameter of disc bulging, and qualitatively assessed lumbar spinal stenosis according to a modified version of Schizas’ classification [Grades A (mild) to C (severe)]. The Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) was used for the assessment of the clinical symptoms. All changes were observable immediately after surgery, progressed over time, and were significantly different statistically at 2 years after surgery. The thecal sac was significantly larger (189% of preoperative; P 0.0001), while the ligamentum flavum and disc bulge were significantly smaller [58.9% and 67.3% of preoperative (P 0.001), respectively]. The number of patients with grade C (severe) lumbar stenosis also dropped significantly (preoperative, 17.6%; 2 years postoperative, 0%). There were no significant differences in JOABPEQ results at 6 months, 1 year, and 2 years postsurgery. Indirect decompression produces immediate positive results that continue to improve over time. The cross-sectional area of the thecal sac doubled by 2 years after surgery, and the ligamentum flavum cross-sectional area and disc bulging both shrank significantly. At the same time, however, postoperative radiographical improvements do not appear to correlate with clinical symptoms. Level of Evidence: 3.

STUDY DESIGN Prospective research in middle-aged and elderly people. OBJECTIVE To investigate low back pain (LBP) and neuropathic pain (NeP); spinal alignment and range of motion (ROM); spinal degenerative changes in plain radiography; osteoporosis; muscle strength; and physical ability as possible risk factors for poor quality of life (QOL). SUMMARY OF BACKGROUND DATA The aging of society has led to an increase in elderly people with chronic pain, including LBP and NeP. However, there has been no analysis of NeP and spinal sagittal alignment as potential risk factors for decreased QOL in the healthy general population. METHODS The subjects were 1128 people (male 473, female 655, average age: 64.3 yrs) who attended an annual health checkup in Yakumo study. The prevalence of LBP and sciatica were investigated using a visual analogue scale (VAS), and NeP was defined as more than or equal to 13 points on the painDETECT questionnaire. Sagittal spinal alignment with spinal ROM was also measured. Body mass index, muscle strength, physical ability, osteoporosis, and lumbar degenerative changes were measured, and 36-item short-form health survey (SF-36) was used for QOL analysis. RESULTS NeP was present in 113 people (10%). The NeP (+) subjects had significantly more severe pain, lower gait speed, higher osteoporosis rate, lumbar kyphosis, and larger spinal inclination (P

Study design A prospective comparative imaging study. Objective This study investigated whether postoperative resolution of spinal cord increased signal intensity (ISI) reflected symptom improvement and surgical outcomes in cervical spondylotic myelopathy (CSM) patients. Summary of background data Although some CSM patients exhibit magnetic resonance imaging (MRI) ISI, its alteration and resolution have not been investigated. The association between postoperative ISI resolution and surgical outcomes in CSM patients remains controversial. Methods A total of 505 consecutive CSM patients (311 males; 194 females) aged a mean of 66.6 years (range, 41-91) were enrolled. All were treated with laminoplasty and underwent MRI scans preoperatively and after an average of 26.5 months postoperatively (range 12-66 months). ISI was classified pre- and postoperatively based on sagittal T2-weighted magnetic resonance images into Grade 0, none; Grade 1, light (obscure); and Grade 2, intense (bright). The patients' pre- and postoperative neurological statuses were evaluated using the Japanese Orthopedic Association scoring system for cervical myelopathy [Japanese Orthopedic Association (JOA) score] and other quantifiable tests, including the 10-s grip and release (10-s G&R) test and 10-s step test. Results A total of 337 patients showed preoperative ISI. Among these, 42 (12.5%) showed postoperative ISI resolution, associated with better postoperative JOA score and recovery rate, 10-s G&R and 10-s step test scores than those who retained it. Patients with preoperative Grade 2 ISI had no postoperative ISI resolution. Patients with ISI improvement from Grade 1 to Grade 0 had better outcomes than those with ISI worsening from Grade 1 to Grade 2. Conclusion Postoperative ISI resolution in CSM patients reflects postoperative symptoms and surgical outcomes. Patients who exhibit ISI resolution have better clinical outcomes. Level of evidence 3.

STUDY DESIGN Self-assembling peptide gel (SPG-178) provides new evidence for the role of a scaffold for treatment of the spinal cord through induction of neuroprotective factors. OBJECTIVE To verify the reproducibility of SPG-178 as scaffold after spinal cord injury, we examine the characteristics of SPG-178 and protective effect on neural cells in vitro and in vivo. SUMMARY OF BACKGROUND DATA The central nervous system extracellular matrix may play a role in maintenance of the neuronal network by inhibiting axonal growth and suppressing formation of additional inadequate synapses. In this study, we show increased expression of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-4 (NT-4), and tropomyosin receptor kinase (TrkA and TrkB) in SPG-178-promoted neurite outgrowth of motor neurons in vitro, and decreased inflammation and glial scar with use of SPG-178 in vivo. METHODS We examined the effect of a self-assembling peptide, SPG-178, as a scaffold for neurite outgrowth of spinal motor neurons in vitro. An in vivo analysis was performed to evaluate if the SPG-178 scaffold attenuated or enhanced expression of various genes after spinal cord injury model rats. RESULTS Expression of NGF, BDNF, NT-4, TrkA, and TrkB increased in SPG-178-promoted neurite outgrowth of motor neurons in vitro. In vivo, SPG-178 increased expression of glial cell line-derived neurotrophic factor and NGF, and decreased glial scar. CONCLUSION This study provides new evidence for the role of SPG-178 as a scaffold in the spinal cord and suggests that this peptide is a neuroprotective factor that may serve as an alternative treatment for neuronal injuries. LEVEL OF EVIDENCE 5.

STUDY DESIGN A prospective cohort study. OBJECTIVE The purpose of this study was to compare surgical outcomes between non-elderly and elderly patients with cervical spondylotic myelopathy (CSM) who underwent laminoplasty. SUMMARY OF BACKGROUND DATA Since age at the time of surgery influences the surgical outcome, we designed a large-scale cohort study to examine the surgical outcome for CSM from a single operative procedure used exclusively in elderly patients. METHODS A total of 505 consecutive patients with CSM (311 men; 194 women) were prospectively enrolled. The mean age was 66.6 years (range, 41-91), and the average postoperative follow-up period was 26.5 ± 12.5 months. Patients were divided into three groups according to age: non-elderly (

Study design A prospective comparative study. Objective This study aimed to establish cervical spine morphometry, alignment, and range of motion (ROM) and to clarify the impact of these age-related and degenerative changes. Summary of background data There are no studies that have evaluated differences in the results of cervical spine radiographs between a large series of cervical spondylotic myelopathy (CSM) patients and healthy subjects. Methods We enrolled 1016 consecutive CSM patients who underwent laminoplasty. CSM patients were also divided based on each decade of life between the fourth and ninth decades. We also enrolled a total of 1230 healthy volunteers as asymptomatic subjects in this study. There were at least 100 men and 100 women in each decade of life between the third and eighth decades. Cervical sagittal alignment on neutral and flexion-extension views was measured by the Cobb method at C2-7. ROM was assessed by measuring the difference in alignment between flexion and extension. Results Cervical lordosis in the neutral position increased gradually with age in both groups. CSM patients showed significantly smaller lordotic angles compared with those shown by asymptomatic subjects within each decade. The total ROM decreased with increasing age in both groups. The total ROM of females was larger than males. The ROM of CSM patients was significantly smaller than asymptomatic subjects. The flexion ROM did not change with aging in either group. There was no significant difference in the flexion ROM between males and females in the two groups. However, the extension ROM decreased gradually in both groups. The extension ROM of CSM patients was significantly smaller than asymptomatic subjects. Conclusion Age-related and degenerative changes in the cervical spine, alignment, and ROM in each decade of life were established between CSM patients and asymptomatic subjects.

Prospective multicenter study.To analyze the incidence of intraoperative spinal neuromonitoring (IONM) alerts and neurological complications, as well as to determine which interventions are most effective at preventing postoperative neurological complications following IONM alerts in high risk spinal surgeries.IONM may play a role in identifying and preventing neural damage; however, few studies have clarified the outcomes of intervention after IONM alerts.We analyzed 2867 patients who underwent surgery for high risk spinal pathology using transcranial electrical motor-evoked potentials from 2010 to 2016. The high-risk spinal surgery cases consisted of 1009 spinal deformity cases, 622 cervical ossification of posterior longitudinal ligament (OPLL) cases, 249 thoracic-OPLL cases, 771 extramedullary spinal cord tumor cases, and 216 intramedullary spinal cord tumor (IMSCT) cases. We set a 70% amplitude reduction as the alarm threshold for transcranial electrical motor-evoked potentials and analyzed the outcomes of the interventions following monitoring alerts and postoperative neurological deficits.The true positive, false positive, true negative, false negative, and rescue cases of IONM comprised 126, 234, 2362, 9, and 136 cases, respectively. Most alerts and interventions occurred during correction and release in deformity cases, posterior decompression and dekyphosis in OPLL cases, and tumor resection and surgery suspension with steroid injection in spinal cord tumor cases; however, individual interventions varied. The rescue rates (number of patients rescued with intervention after IONM alert/number of true positive cases plus rescue cases) for deformity, cervical-OPLL, thoracic--OPLL, extramedullary spinal cord tumor, and IMSCT cases were 61.4% (35/57), 82.1% (32/39), 40% (20/50), 52.5% (31/59), and 31.6% (18/57), respectively.Our prospective multicenter study identified potential neural damage in 9.5% of cases and 52% rescue cases using IONM. Although the rescue ratios for t-OPLL and IMSCT were relatively low, appropriate intervention immediately after an IONM alert may prevent neural damage even in high-risk spinal surgeries.3.

Prospective, multicenter, nationwide study.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.There is no prospective multicenter study of surgical complications and risk factors for T-OPLL, and previous multicenter retrospective studies have lacked details.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.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.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.3.

STUDY DESIGN Retrospective comparative study. OBJECTIVE To compare the surgical results of anterior and posterior combined surgery (AP) and posterior fixation with vertebroplasty (VP) for treating osteoporotic delayed vertebral collapse. SUMMARY OF BACKGROUND DATA The optimal treatment of osteoporotic delayed vertebral collapse has been controversial. Because of aged patients' numerous comorbid medical complications and frequent instrumentation failure secondary to osteoporosis, it is challenging for surgeons to manage osteoporotic delayed vertebral collapse. In spite of this, there have been few reports comparing the surgical results. METHODS A total of 93 patients with osteoporotic delayed vertebral fracture who underwent spinal surgery were enrolled at 6 hospitals. Sixty-five patients underwent AP surgery in 3 hospitals, and 28 patients underwent VP surgery in the other 3 hospitals. We restricted the spinal-fracture level to thoracolumbar lesion (T10-L2) and excluded patients followed up more than 2 years after surgery. The final numbers of patients included in this study were 24 in the AP group and 21 in the VP group. There were no significant differences between the 2 groups in terms of age, sex, disease duration, or duration of follow-up. RESULTS Operative time was significantly longer and intraoperative blood loss significantly greater in the AP group. No significant difference between the 2 groups was observed in neurological improvement or the angle of kyphosis correction. However, the loss of correction was significantly greater in the VP group. There were no significant differences in perioperative respiratory or other complications. Implant-related complications and pseudarthrosis were more often observed in the VP group. One patient in the VP group underwent additional surgery for progression kyphosis. CONCLUSION AP surgery provides stable spinal fixation and reduces implant failure particularly at the thoracolumbar junction because of load bearing of anterior spinal elements. Surgery-related complications in AP surgery were as few in number as with the VP group, and AP surgery is useful for osteoporotic delayed vertebral fracture.

Retrospective multicenter study.The goal of this study is to determine the characteristic imaging features of spinal ependymoma in a review of magnetic resonance imaging (MRI) data for a large series of surgically proven cases.Common spinal intramedullary neoplasms are mostly ependymomas and comprise 50% to 60% of spinal neuroepithelial tumors in adults. Preoperative prediction of the pathological diagnosis could enhance surgical planning and explanation of the procedure to patients. However, these types of tumors exhibit a variety of MRI findings.Records were examined for 59 patients who underwent surgery for spinal cord ependymoma and had a pathological diagnosis of cellular ependymoma of World Health Organization classification grade II.The ependymomas included 28 in the cervical spine, 34 in the thoracic spine, and 3 conus lesions. All cases were isointense or hypointense on T1-weighted MRI, and 55 (93%) were hyperintense on T2-weighted MRI. Tumors were located centrally in all cases; 50 (85%) showed surrounding cord edema; and 52 (88%) had associated cysts, including 36 (61%) rostral or caudal cysts, 10 (17%) intratumoral cysts, and 6 (10%) with syringomyelia. Of the 59 tumors, 17 (29%) showed the "cap sign," a rim of extreme hypointensity seen around the tumor on T2-weighted images, due to hemosiderin. In gadolinium-enhanced MRI, all cases were enhanced, and 27 (46%), 16 (27%), 11 (19%), and 5 (8%) cases showed homogeneous, heterogeneous, rim, and nodular enhancement, respectively.Hypointense changes on T2-weighted MRI and hemosiderin deposition reflect easy bleeding. Tumors are associated with various types of cysts, and gadolinium-enhancement patterns reflect a variety of intratumor cellular components. In cases in which the whole tumor shows gadolinium enhancement on MRI, rostral, or caudal cyst and a cap sign with hemorrhage are characteristics of grade II classical ependymoma.3.

A prospective imaging study.The study investigated whether the classification of increased signal intensity (ISI) using magnetic resonance imaging (MRI) reflects the severity of symptoms in patients with cervical spondylotic myelopathy (CSM).Although the ISI on MRI in patients with CSM is observed, the degree of ISI has not been examined. The association between ISI and the surgical outcomes in cervical myelopathy remains controversial.A total of 505 consecutive patients with CSM (311 males; 194 females) were enrolled. The mean age was 66.6 years (range, 41-91 yrs), with an average postoperative follow-up period of 26.5 ± 12.5 months. The ISI was classified into three groups based on sagittal T2-weighted MRI as follows: Grade 0, none; Grade 1, light (obscure); and Grade 2, intense (bright). Pre- and postoperative neurological status was evaluated using the Japanese Orthopedic Association scoring system for cervical myelopathy (JOA score) and quantifiable tests, including the 10-s grip and release test (10-s GR test) and the 10-s step test.The preoperative MRI showed 168 patients in Grade 0, 169 patients in Grade 1, and 168 in Grade 2, with no age differences among three groups. Grade 2 patients had a longer duration of symptom compared with the other grades. Grade 0 patients had a better postoperative JOA score and recovery rate compared with the other grades. The preoperative and postoperative scores in the GR test and steps were better in the Grade 0 patients compared with the other grades. Grade 1 and 2 patients had similar outcomes and recovery rates.ISI on MRI in patients with CSM was prospectively classified into three grades. The ISI grading was not associated with the preoperative severity of myelopathy and outcomes.2.

Study design Prospective randomized study. Objective This study aimed to prospectively compare the surgical results of the open- and French-door laminoplasty. Summary of background data Cervical laminoplasty is a common surgical procedure for the treatment of cervical compressive myelopathy. These procedures are primarily classified as either open- or French-door laminoplasties. Only few prospective studies comparing the surgical results of the 2 procedures are available. Methods A total of 92 patients with cervical compressive myelopathy who underwent cervical laminoplasty were prospectively enrolled and randomized into the following 2 groups according to the type of laminoplasty: open-door and French-door groups. A single attending spine surgeon performed all surgical procedures. The following factors were evaluated: surgical duration, blood loss, perioperative complications, neurological assessment using the Japanese Orthopedic Association score, and recovery rate. Radiological evaluations included assessment of the cervical lordotic angle and cervical range of motion. In addition, the ratio of postoperative spinal lamina opening was evaluated by magnetic resonance imaging. Results There were no differences in perioperative complications and neurological outcomes between the 2 groups. The mean reduction in cervical lordotic angle after surgery was significantly greater in the open-door group than the French-door group (3.0° vs. 5.6°). Postoperative cervical range of motion significantly decreased in the open-door group than in the French-door group (19.3° vs. 26.0°). Postoperative cervical lordotic angle in the extension position significantly diminished in the open-door group than in the French-door group (7.9° vs. 14.1°). The ratio of opening of the spinal lamina after surgery was significantly larger in the open-door group than in the French-door group. Conclusion The 2 laminoplasty methods showed almost the same neurological recovery as well as perioperative complications. In cases of open-door laminoplasty, postoperative cervical alignment became more kyphotic and cervical range of motion was more restricted than that in French-door laminoplasty cases after surgery. French-door laminoplasty is preferable to open-door laminoplasty for postoperative cervical alignments. Level of evidence 1.