Multimodal Deep Learning-based Radiomics Approach for Predicting Surgical Outcomes in Patients with Cervical Ossification of the Posterior Longitudinal Ligament.

STUDY DESIGN: A retrospective analysis. OBJECTIVE: This research sought to develop a predictive model for surgical outcomes in patients with cervical ossification of the posterior longitudinal ligament (OPLL) using deep learning and machine learning (ML) techniques. SUMMARY OF BACKGROUND DATA: Determining surgical outcomes assists surgeons in communicating prognosis to patients and setting their expectations. Deep learning and ML are computational models that identify patterns from large datasets and make predictions. METHODS: Of the 482 patients, 288 patients were included in the analysis. A minimal clinically important difference (MCID) was defined as gain in Japanese Orthopaedic Association (JOA) score of 2.5 points or more. The predictive model for MCID achievement at 1 year post-surgery was constructed using patient background, clinical symptoms, and preoperative imaging features (x-ray, CT, MRI) analyzed via LightGBM and deep learning with RadImagenet. RESULTS: The median preoperative JOA score was 11.0 (IQR: 9.0-12.0), which significantly improved to 14.0 (IQR: 12.0-15.0) at 1 year after surgery (P < 0.001, Wilcoxon signed-rank test). The average improvement rate of the JOA score was 44.7%, and 60.1% of patients achieved the MCID. Our model exhibited an area under the receiver operating characteristic curve of 0.81 and the accuracy of 71.9% in predicting MCID at 1 year. Preoperative JOA score and certain preoperative imaging features were identified as the most significant factors in the predictive models. CONCLUSION: A predictive ML and deep learning model for surgical outcomes in OPLL patients is feasible, suggesting promising applications in spinal surgery. LEVEL OF EVIDENCE: 4.

Risk factors for early-onset adjacent segment degeneration after one-segment posterior lumbar interbody fusion.

Adjacent segment degeneration (ASD) is a major postoperative complication associated with posterior lumbar interbody fusion (PLIF). Early-onset ASD may differ pathologically from late-onset ASD. The aim of this study was to identify risk factors for early-onset ASD at the cranial segment occurring within 2 years after surgery. A retrospective study was performed for 170 patients with L4 degenerative spondylolisthesis who underwent one-segment PLIF. Of these patients, 20.6% had early-onset ASD at L3-4. In multivariate logistic regression analysis, preoperative larger % slip, vertebral bone marrow edema at the cranial segment on preoperative MRI (odds ratio 16.8), and surgical disc space distraction (cut-off 4.0 mm) were significant independent risk factors for early-onset ASD. Patients with preoperative imaging findings of bone marrow edema at the cranial segment had a 57.1% rate of early-onset ASD. A vacuum phenomenon and/or concomitant decompression at the cranial segment, the degree of surgical reduction of slippage, and lumbosacral spinal alignment were not risk factors for early-onset ASD. The need for fusion surgery requires careful consideration if vertebral bone marrow edema at the cranial segment adjacent to the fusion segment is detected on preoperative MRI, due to the negative impact of this edema on the incidence of early-onset ASD.

Management of Cervical Spinal Cord Injury without Major Bone Injury in Adults.

The incidence of cervical spinal cord injury (CSCI) without major bone injury is increasing, possibly because older people typically have pre-existing cervical spinal canal stenosis. The demographics, neurological injury, treatment, and prognosis of this type of CSCI differ from those of CSCI with bone or central cord injury. Spine surgeons worldwide are debating on the optimal management of CSCI without major bone injury. Therefore, this narrative review aimed to address unresolved clinical questions related to CSCI without major bone injury and discuss treatment strategies based on current findings. The greatest divide among spine surgeons worldwide hinges on whether surgery is necessary for patients with CSCI without major bone injury. Certain studies have recommended early surgery within 24 h after injury; however, evidence regarding its superiority over conservative treatment remains limited. Delayed MRI may be beneficial; nevertheless, reliable factors and imaging findings that predict functional prognosis during the acute phase and ascertain the necessity of surgery should be identified to determine whether surgery/early surgery is better than conservative therapy/delayed surgery. Quality-of-life assessments, including neuropathic pain, spasticity, manual dexterity, and motor function, should be performed to examine the superiority of surgery/early surgery to conservative therapy/delayed surgery.

Prognostic Factors for the Postoperative Improvement of Spinal Cord-Related Neuropathic Pain in Patients with Degenerative Cervical Myelopathy.

Introduction: The number of patients with degenerative cervical myelopathy (DCM) requiring surgical treatment has markedly increased in today's aging society. Such patients often exhibit impaired activities of daily living because of motor dysfunction as well as neuropathic pain (NeP). Although many studies have demonstrated the safety and efficacy of surgical treatment for DCM, residual postoperative NeP has not been well described. Therefore, this study aimed to identify the predictors of postoperative NeP improvement in patients with DCM. Methods: This retrospective study included 92 outpatients with postoperative chronic NeP (≥3 months) related to DCM. Data were obtained from clinical information, magnetic resonance imaging (MRI) findings, and patient-based questionnaires using the Neuropathic Pain Symptom Inventory (NPSI) and the Brief Scale for Psychiatric Problems in Orthopaedic Patients. Univariate and multivariate analyses were performed for patients with NPSI improvement rates <30% and ≥30% to identify prognostic factors. Results: Among 92 patients, 61 (66.3%) had residual NeP, with a low improvement rate even after surgery. The independent negative prognostic factors for NeP improvement after surgery were older age at operation (odds ratio (OR): 0.932), longer symptom duration before surgery (OR: 0.589), and higher preoperative NPSI score (OR: 0.932). The cut-off value of symptom duration before surgery for postoperative NeP improvement was 1 year. By contrast, the preoperative Japanese Orthopaedic Association score and MRI findings, including signal intensity change and the degree of spinal cord compression, were not associated with postoperative NeP improvement. Moreover, even in patients with an NPSI improvement rate ≥30%, the NPSI subscores for deep pain and paresthesia/dysesthesia remained high. Conclusions: Discrepancies between physician- and image-based assessments and patient-based assessments were identified as factors associated with improvement in postoperative NeP. Our findings are important for both spine surgeons and patients to manage patient expectations with respect to recovery during the postoperative course.

Clinical impact of short limited lumbar fusion for adult spinal deformity with postural and radiological abnormalities.

Extensive surgical spinopelvic fusion for patients with adult spinal deformity (ASD) to achieve optimal radiological parameters should be avoided. The aim of this study was to review clinical and imaging findings in patients with ASD with postural and radiological abnormalities who underwent a novel three-level limited lumbar fusion as two-stage surgery in an attempt to propose a better tolerated alternative to spinopelvic long fusion to the pelvis. The subjects were 26 patients with a minimum follow-up period of 2 years. Cobb angle, C7 sagittal vertical axis, and pelvic incidence (PI) minus lumbar lordosis (LL) were significantly improved after surgery and maintained at follow-up. Most radiological parameters were corrected with lateral interbody fusion (LIF) as the initial surgery, and few with posterior fusion. PI-LL remained high after limited lumbar fusion, but scores on patient-based questionnaires and sagittal and coronal tilt in gait analysis improved. In cases with postoperative progression of proximal junctional kyphosis (11.5%), residual L1-L2 local kyphosis after LIF was the most significant radiological feature. In some cases of ASD with postural abnormalities, short limited lumbar fusion gives sufficient postoperative clinical improvement with preservation of spinal mobility and activities of daily living. The range of fixation should be determined based on radiological parameters after LIF to avoid postoperative complications.

Prognosis after Palliative Surgery for Patients with Spinal Metastasis: Comparison of Predicted and Actual Survival.

Prediction of prognosis is a key factor in therapeutic decision making due to recent the development of therapeutic options for spinal metastases. The aim of the study was to examine predictive scoring systems and identify prognostic factors for 6-month mortality after palliative surgery. The participants were 75 patients with spinal metastases who underwent palliative surgery and had a minimum follow-up period of 1 year. Associations of actual survival with categories based on the revised Tokuhashi score and new Katagiri score were evaluated. Univariate and multivariate analyses were performed to identify prognostic factors for 6-month mortality after palliative surgery. The median actual survival period was longer than those predicted using the scoring systems. However, 21.3% of patients died of cancers within 6 months after surgery. A higher CRP/albumin ratio (odds ratio: 0.39; cut-off 0.409) and absence of postoperative adjuvant therapy (odds ratio: 7.15) were independent risk factors for 6-month mortality. There was no association of mortality with primary site, severity of sarcopenia, or other biomarkers. These results suggest that careful consideration is needed to determine whether palliative surgery is the best option for patients with a high preoperative CRP/albumin ratio and/or absence of postoperative adjuvant therapy, regardless of predictions made from scoring systems.

Prognostic Factors and Optimal Surgical Management for Lumbar Spinal Canal Stenosis in Patients with Diffuse Idiopathic Skeletal Hyperostosis.

Lumbar spinal canal stenosis (LSS) and diffuse idiopathic skeletal hyperostosis (DISH) tend to develop in the elderly, resulting in an increased need for lumbar surgery. However, DISH may be a risk factor for poor clinical outcomes following lumbar decompression surgery, especially in patients with DISH extending to the lumbar segment (L-DISH). This study aimed to identify the prognostic factors of LSS with L-DISH and propose an optimal surgical management approach to improve clinical outcomes. Of 934 patients who underwent lumbar decompression surgery, 145 patients (15.5%) had L-DISH. In multivariate linear regression analysis of the JOA score improvement rate, the presence of vacuum phenomenon at affected segments (estimate: −15.14) and distance between the caudal end of L-DISH and decompressed/fused segments (estimate: 7.05) were independent prognostic factors. In logistic regression analysis of the surgical procedure with JOA improvement rate > 25% in L-DISH patients with both negative prognostic factors, the odds ratios of split laminotomy and short-segment fusion were 0.64 and 0.21, respectively, with conventional laminotomy as the reference. Therefore, to achieve better clinical outcomes in cases with decompression at the caudal end of L-DISH, decompression surgery without fusion sparing the osteoligamentous structures at midline should be considered as the standard surgery.

Symptom-based pharmacotherapy for neuropathic pain related to spinal disorders: results from a patient-based assessment.

Existing guidelines advocate an updated therapeutic algorithm for chronic neuropathic pain (NeP), but pharmacotherapeutic management should be individualized to pain phenotypes to achieve higher efficacy. This study was aimed to evaluate the efficacy of medications, based on NeP phenotypes, and to propose symptom-based pharmacotherapy. This retrospective study was enrolled 265 outpatients with chronic NeP related to spinal disorders. The patients were classified into three groups: spinal cord-related pain, radicular pain, and cauda equina syndrome. Data were obtained from patient-based questionnaires using Neuropathic Pain Symptom Inventory (NPSI) and the Brief Scale for Psychiatric Problems in Orthopaedic Patients, and from clinical information. The proportions of patients with ≥ 30% and ≥ 50% reduction in NPSI score for each pain subtype (spontaneous pain, paroxysmal pain, evoked pain, and paresthesia/dysesthesia) and drugs were evaluated. The pain reduction rate was significantly lower in patients with spinal cord-related pain, especially for paresthesia/dysesthesia. For spinal cord-related pain, duloxetine and neurotropin had insufficient analgesic effects, whereas mirogabalin was the most effective. Pregabalin or mirogabalin for radicular pain and duloxetine for cauda equina syndrome are recommended in cases of insufficient analgesic effects with neurotropin. The findings could contribute to better strategies for symptom-based pharmacotherapeutic management.

Prognostic Factors for Cervical Spinal Cord Injury without Major Bone Injury in Elderly Patients.

In the current aging society, there has been a marked increase in the incidence of cervical spinal cord injury (CSCI) without major bone injury. This multi-center study aimed to identify predictors of neurological improvement in elderly patients with CSCI without major bone injury. The participants were 591 patients aged ≥65 years with CSCI without major bone injury and a minimum follow-up period of three months. Neurologic status was defined using the American Spinal Injury Association (ASIA) impairment scale (AIS). Univariate and multi-variate analyses were performed to identify prognostic factors for walking recovery in AIS A-C cases and full upper extremity motor recovery in AIS D cases. In AIS A-C cases, body mass index (odds ratio (OR): 1.112), magnetic resonance imaging signal change (OR: 0.240), AIS on admission (OR: 3.497), comorbidity of dementia/delirium (OR: 0.365), and post-injury pneumonia (OR: 0.194) were identified as independent prognostic factors for walking recovery. The prevalence of ossification of the posterior longitudinal ligament (OR: 0.494) was also found to be an independent prognostic factor in AIS B and C cases only. In AIS D cases, age (OR: 0.937), upper extremity ASIA motor score on admission (OR: 1.230 [per 5 scores]), and operation (OR: 0.519) were independent prognostic factors for full motor recovery. The severity of AIS at admission was the strongest predictor of functional outcomes. Promoting rehabilitation, however, through measures to reduce cognitive changes, post-injury pneumonia, and unhealthy body weight changes can contribute to greater neurological improvement in AIS A-C cases.

Risk Factors and Prevention of C5 Palsy After Anterior Cervical Decompression and Fusion: Similarity of the Pathomechanism With That After a Posterior Approach.

STUDY DESIGN: This was a retrospective study. OBJECTIVE: The objective of this study was to review clinical and imaging findings after anterior cervical decompression and fusion, as a basis for prevention of C5 palsy. SUMMARY OF BACKGROUND DATA: C5 palsy is a common postoperative complication in spine surgery, but the mechanistic basis for this condition is unknown. MATERIALS AND METHODS: The subjects were 239 patients with cervical myelopathy who underwent anterior cervical decompression and fusion including at C4-C5 disk level at our hospital from 2001 to 2018. Twelve of these patients (5.0%) had C5 palsy postoperatively. Clinical features and imaging findings were compared in patients with and without C5 palsy. RESULTS: In patients with C5 palsy, the sagittal alignment of the cervical spine was kyphotic, the width of the C5 intervertebral foramen was narrower, and the lateral decompressed line was wider beyond the medial part of the Luschka joint. Age, sex, disease, the number of fused segments, decompression width, and anterior shift of the spinal cord did not differ significantly between patients with and without C5 palsy. CONCLUSIONS: These results indicate that the pathomechanism of C5 palsy may be dependent on the location of the lateral decompression line, especially in patients with cervical kyphosis and a narrow C5 intervertebral foramen. Excessive lateral decompression beyond the Luchka joint might lead to C5 root kinking between the intervertebral foramen and posterior edge of vertebra. This pathomechanism may be similar in anterior and posterior approaches. To prevent C5 palsy, the medial line of the Luschka joint should be confirmed intraoperatively and decompression should be performed within the Luschka joints. Alternatively, medial foraminotomy should be used in cases needing wide decompression, such as those with massive ossification of the posterior longitudinal ligament, lateral osteophytes, and symptomatic foraminal stenosis. LEVEL OF EVIDENCE: Level III.

Negative impact of short-level posterior lumbar interbody fusion in patients with diffuse idiopathic skeletal hyperostosis extending to the lumbar segment.

OBJECTIVE: The development of diffuse idiopathic skeletal hyperostosis (DISH) often requires further surgery after posterior decompression without fusion because of postoperative intervertebral instability. However, there is no information on whether fusion surgery is recommended for these patients as the standard surgery. The aim of this study was to review the clinical and imaging findings in lumbar spinal canal stenosis (LSS) patients with DISH affecting the lumbar segment (L-DISH) and to assess the indication for fusion surgery in patients with DISH. METHODS: A total of 237 patients with LSS underwent 1- or 2-level posterior lumbar interbody fusion (PLIF) at the authors' hospital and had a minimum follow-up period of 2 years. Patients with L-DISH were classified as such (n = 27, 11.4%), whereas those without were classified as controls (non-L-DISH; n = 210, 88.6%). The success rates of short-level PLIF were compared in patients with and those without L-DISH. The rates of adjacent segment disease (ASD), pseudarthrosis, postoperative symptoms, and revision surgery were examined in the two groups. RESULTS: L-DISH from L2 to L4 correlated significantly with early-onset ASD, pseudarthrosis, and the appearance of postsurgical symptoms, especially at a lower segment and one distance from the segment adjacent to L-DISH, which were associated with the worst clinical outcome. Significantly higher percentages of L-DISH patients developed ASD and pseudarthrosis than those in the non-L-DISH group (40.7% vs 4.8% and 29.6% vs 2.4%, respectively). Of those patients with ASD and/or pseudarthrosis, 69.2% were symptomatic and 11.1% underwent revision surgery. CONCLUSIONS: The results highlighted the negative impact of short-level PLIF surgery for patients with L-DISH. Increased mechanical stress below the fused segment was considered the reason for the poor clinical outcome.

Distribution and Polarization of Hematogenous Macrophages Associated with the Progression of Intervertebral Disc Degeneration.

STUDY DESIGN: In vivo study using immunostaining and immunoblot analysis. OBJECTIVE: To determine the distribution of bone marrow-derived macrophages (BMDMs), macrophage polarization and cytokine expression in the process of intervertebral disc (IVD) degeneration. SUMMARY OF BACKGROUND DATA: Knowledge of the detailed distribution of exogeneous macrophages in the disc degeneration process is important for understanding the pathomechanisms and establishing novel therapeutic targets. METHODS: To distinguish BMDMs, GFP-labeled bone marrow chimeric rats (n = 12) were generated. The degenerative process of the intervertebral disc was reproduced in a rat caudal disc puncture model (n = 49). Immunofluorescence staining was performed to observe the distribution of BMDMs, Iba-1 and GFP double-positive cells, and Iba-1 and iNOS (M1 macrophage) or arginase-1 (M2 macrophage) double-positive cells. Immunoblot analysis was used to evaluate differences in cytokines (TNF-α, IL-1ß, IL-6, TGF-ß, IL-4, and IL-10) depending on the distribution of BMDMs. RESULTS: BMDMs infiltrated into the outer annulus fibrosus and endplate, while increasing tissue-resident macrophage was observed inside the annulus fibrosus/nucleus pulposus. The ratio of BMDMs and the polarity change differed among the regions. Especially in the endplate, BMDMs increased gradually and the macrophage phenotype was M2 dominant. Expression of IL-1ß decreased gradually at endplate, and that of IL-4 increased early after disc puncture at inside of the annulus fibrosus. CONCLUSION: During the disc degeneration process, BMDMs were observed mainly around the endplate and outside area of the annulus fibrosus, with few in the inside area of annulus fibrosus and nucleus pulposus. Compared to other IVD area, macrophage polarity and cytokine expression is concomitantly M2-dominant in endplate. Increased hematogenous M2-phenotype macrophages in endplate with progression of IVD degeneration could enhance our understanding of the underlying mechanisms of disc degeneration.Level of Evidence: N/A.

Symptom-based characteristics and treatment efficacy of neuropathic pain related to spinal disorders.

BACKGROUND: Symptom-based therapeutic management is required for neuropathic pain (NeP) to achieve higher treatment efficacy. In spinal disorders, which have a high prevalence of NeP, neurological symptoms are classified into myelopathy, radiculopathy, and cauda equina syndrome. The characteristics of pain and the treatment efficacy for each of these symptoms require clarification. METHODS: A retrospective patient-based outcome study was conducted in 265 outpatients with chronic NeP (≥3 months) related to spinal disorders. The patients were classified into three groups according to their neurological symptoms: spinal cord-related pain, radicular pain, and cauda equina syndrome. Data were obtained from patient-based questionnaires using the Neuropathic Pain Symptom Inventory (NPSI) and the Brief Scale for Psychiatric Problems in Orthopaedic Patients (BS-POP), and from clinical information. RESULTS: Most of the patients with NeP had a NPSI score >10 (moderate to severe pain) and 40% had psychiatric problems. The common subtype of NeP was spontaneous pain and paresthesia/dysesthesia in patients with radicular pain and cauda equina syndrome, whereas more severe paresthesia/dysesthesia was particularly prominent in patients with spinal cord-related pain. The pain reduction rate was significantly lower in these latter patients, especially in association with residual paresthesia/dysesthesia. CONCLUSIONS: The characteristics and treatment efficacy of NeP in patients with spinal disorders varied according to neurological symptoms. Effective treatment was difficult, especially for paresthesia/dysesthesia in patients with spinal cord-related pain. These findings enhance the understanding of the underlying mechanisms of pain and could help in design of symptom-based therapeutic management.

Relationship Between Vertebral Bone Marrow Edema and Early Progression of Intervertebral Disc Wedge or Narrowing After Lumbar Decompression Surgery.

STUDY DESIGN: A retrospective study. OBJECTIVES: The aim of this study was to review clinical and imaging features in patients with lumbar spinal canal stenosis (LSS) with and without postoperative early progression of intervertebral disc degeneration (IDD) and to identify predictive factors. SUMMARY OF BACKGROUND DATA: Progression of IDD after lumbar decompression surgery can induce low back pain and leg pain, and may require revision surgery. However, risk factors for postoperative radiological changes indicating IDD linked to development of symptoms have not been described. METHODS: We included 564 patients with LSS without degenerative lumbar scoliosis who underwent lumbar decompression surgery without fusion. Clinical features and imaging findings were compared in cases with (group P) and without (group N) progression of IDD (intervertebral disc wedge or narrowing) at 1 year after surgery. RESULTS: Of the 564 patients, 49 (8.7%) were in group P. On preoperative MRI, all patients in group P had findings of vertebral bone marrow edema (diffuse high intensity on T2-weighted images and low-intensity on T1-weighted images), compared to only 5.4% in group N. The rate of revision surgery was significantly higher in group P in 5 years' follow-up (12.2% vs. 1.4%, P < 0.01). In group P, 44.9% of patients developed postoperative symptoms associated with postoperative radiological changes, and the frequency was higher in narrowing-type than in wedge-type cases. Vertebral bone marrow edema area and IDD grade were not predictors for postoperative early IDD progression. CONCLUSION: Careful consideration is required to determine whether lumbar decompression surgery should be performed if vertebral bone marrow edema is detected on MRI, since this is a predictor for a negative clinical outcome. If surgery is symptomati-cally urgent, careful clinical and radiological follow-up is required.Level of Evidence: 4.

Short-Term Outcome and Predictors of Therapeutic Effects of Intradiscal Condoliase Injection for Patients with Lumbar Disc Herniation.

INTRODUCTION: Intradiscal chondroitin sulfate ABC endolyase (condoliase) injection for lumbar disc herniation (LDH) is an intermediate between conservative treatment and surgery. This approach can only be performed once in a lifetime; therefore, understanding the factors that determine the indication for the use of condoliase and predict outcomes is important. The aim of this study was to review clinical and imaging findings in patients after intradiscal condoliase injection, and to assess the short-term outcomes and factors associated with therapeutic effects. METHODS: The subjects were 42 patients with LDH who underwent intradiscal condoliase injection. Patients with and without a ≥50% improvement from baseline of leg pain at 3 months after injection were defined as responders and non-responders, respectively. Clinical features and radiological findings were compared between these groups. RESULTS: Of the 42 patients, 32 (76.2%) were responders and 10 (23.8%) were non-responders. Of 8 patients with a history of discectomy at the same level as LDH, 6 (75.0%) were responders. Non-responders had a significantly longer time from onset to treatment, smaller herniated volume before treatment, lower percentage reduction of herniated mass, and less intervertebral disc degeneration before treatment. There were no significant differences in LDH types (subligamentous extrusion or transligamentous extrusion types), high-intensity area within the herniation, changes in disc height, and region of condoliase injection between the two groups. CONCLUSIONS: Intradiscal condoliase injection had a good short-term therapeutic effect in patients with LDH, including in transligamentous extrusion-type and revision cases as well as subligamentous extrusion-type cases. Administration of intradiscal condoliase injection may be most effective in patients with a larger herniated mass volume before treatment, and least effective in cases with a longer time and less intervertebral disc degeneration before treatment.

Clinical and imaging features of surgically treated low lumbar osteoporotic vertebral collapse in patients with Parkinson's disease.

Osteoporosis and Parkinson's disease (PD) are age-related diseases, and surgery for osteoporotic vertebral collapse (OVC) in PD patients become more common. OVC commonly affects the thoracolumbar spine, but low lumbar OVC is frequent in patients with lower bone mineral density (BMD). The aim of this study was to identify differences in clinical and imaging features of low lumbar OVC with or without PD and to discuss the appropriate treatment. The subjects were 43 patients with low lumbar OVC below L3 who were treated surgically, including 11 patients with PD. The main clinical symptoms were radicular pain in non-PD cases and a cauda equina sign in PD cases. Rapid progression and destructive changes of OVC were seen in patients with PD. The morphological features of OVC were flat-type in non-PD cases with old compression fracture, and destruction-type in PD cases without old compression fracture. Progression of PD was associated with decreased lumbar lordosis, lower lumbar BMD, and severe sarcopenia. High postoperative complication rates were associated with vertebral fragility and longer fusion surgery. Progression of postural instability as a natural course of PD may lead to mechanical stress and instrumentation failure. Invasive long-fusion surgery should be avoided for single low lumbar OVC.

Pathomechanism and prevention of further surgery after posterior decompression for lumbar spinal canal stenosis in patients with diffuse idiopathic skeletal hyperostosis.

BACKGROUND CONTEXT: Diffuse idiopathic skeletal hyperostosis (DISH) is a risk factor for further surgery after posterior decompression without fusion for patients with lumbar spinal canal stenosis (LSS). However, a strategy to prevent revision surgery has not been described. PURPOSE: The aim of this study was to review clinical and imaging findings in LSS patients with DISH extending to the lumbar segment and to propose countermeasures for prevention of revision surgery. STUDY DESIGN: A retrospective study. PATIENTS SAMPLE: A total of 613 consecutive patients with LSS underwent posterior decompression without fusion at our hospital and had a minimum follow-up period of 2 years. We defined patients with DISH bridging to the lumbar segment as L-DISH cases (group D, n=111), and those without as non-L-DISH cases (group N, n=502). OUTCOME MEASURE: Demographic data including the rate of revision surgery, neurological examination using Japanese Orthopaedic Association score, radiological studies comprised plain lumbar radiography, CT, and high-resolution MRI were assessed. METHODS: Clinical features and imaging findings were compared in patients with and without L-DISH. Revision surgery and surgical procedures (conventional laminotomy or lumbar spinous process-splitting [split] laminotomy) were examined in the two groups. No funding was received for this study. RESULTS: L-DISH from L2 to L4 was a risk factor for disc degeneration such as a vacuum phenomenon and for further surgical treatment. The rate of revision surgery was higher in group D than in group N (9.0% vs. 4.0%, p=.026). There was no significant difference in this rate for patients in groups D and N who underwent conventional laminotomy; however, for those who underwent split laminotomy, the rate was significantly higher in group D (16.7% vs. 2.1%, p=.0006). Furthermore, the rate of revision surgery after split laminotomy at a lower segment adjacent to L-DISH was significantly higher than that after conventional laminotomy (37.5% vs. 7.7%, p=.037). CONCLUSIONS: A negative impact of lumbar spinous process-splitting laminotomy was found, especially with decompression at a lower segment adjacent to L-DISH. In such cases, surgery sparing the osteoligamentous structures at midline, including the spinous process and supra- and interspinous ligaments, should be selected.

Differences in clinical and radiological features of thoracic disc herniation presenting with acute progressive myelopathy.

PURPOSE: Symptomatic thoracic disc herniation (TDH) is relatively rare, but patients with progressive myelopathy require surgical treatment without delay in diagnosis. The aim of this study was to review clinical and radiological features in patients with TDH presenting with myelopathy. METHODS: A total of 28 consecutive patients with thoracic myelopathy (Frankel grade C or worse) due to TDH who underwent surgery were divided into 3 groups based on the time for development of myelopathy (acute (< 72 h), subacute (within a few weeks), and chronic [gradually over > 1 month)] and their data were analyzed. RESULTS: The patients in the acute group were significantly younger and had a higher body mass index (BMI) compared to those in the subacute and chronic groups. Most cases of acute myelopathy were affected in the upper thoracic level, whereas all patients with subacute and chronic myelopathy had lesions in the lower thoracic level below T8-9. Interestingly, the affected thoracic level in patients with acute myelopathy matched the upper line of the sternum. The rate of acquired walking ability without assistance was only 50.0% in the acute group. CONCLUSIONS: This study suggests that TDH presenting with acute myelopathy may have different clinical and radiological features compared to those of TDH with subacute and chronic myelopathy. Upper TDH should be suspected in cases of acute myelopathy that develops with sudden-onset back pain after certain triggers in younger and higher BMI people. These affected thoracic level matched with the upper line of the sternum in each case.

Primary intradural extramedullary Ewing sarcoma: A case report and literature review.

Tumors of the spinal cord and cauda equina show a wide spectrum of histology and require careful diagnosis and treatment. Primary intradural extramedullary Ewing sarcoma (IEES) is extremely rare, and initial imaging and clinical findings for this tumor mimic those of benign intradural spinal tumors. The present report describes a case of a 35-year-old woman who presented with IEES with meningeal seeding, and the literature on the management and clinical course of these tumors was reviewed. An examination revealed right-side leg dominant rapidly progressive hypoesthesia and motor deficits. MRI identified intradural tumors at the T12-L1 and L4-5 levels. Growth and an increase in the number of intradural tumors occurred over 3 weeks. Gadolinium-contrast T1-weighted MRI revealed diffusely enhanced signals for tumorous lesions with meningeal seeding in the cervical and thoracic spinal cord. Excision of a tumor at T12-L1 was performed to alleviate the symptoms and to make a histologic diagnosis. Microscopically, the tumor consisted of dense sheets of small round cells. Immunohistochemically, tumor cells showed intense and diffuse positive staining for CD99, ETS transcription factor ERG and Fli-1 proto-oncogene, ETS transcription factor (FLI1). The sequence analysis revealed the EWS RNA binding protein 1-FLI1 fusion transcript. The lesion was diagnosed as primary intradural ES. Adjuvant chemotherapy following radiotherapy for the whole spine was performed; however, multiple brain metastases were found at 10 months after diagnosis and the patient died of diffusely disseminated disease limited to the central nervous system without evidence of distant metastases at 16 months after the initial diagnosis. In a literature review of IEES cases, the 1- and 5-year overall survival rates were 79.8 and 26.6%, respectively, and the 1-, 2- and 5-year progression-free survival rates were 61.0, 52.3 and 10.9%, respectively. Therefore, primary IEES has a poor prognosis compared with ES of bone, and novel agents and treatment strategies are required.

Expression Analysis of Susceptibility Genes for Ossification of the Posterior Longitudinal Ligament of the Cervical Spine in Human OPLL-related Tissues and a Spinal Hyperostotic Mouse (ttw/ttw).

STUDY DESIGN: Immunohistochemical and real-time reverse transcription-polymerase chain reaction (RT-PCR) analysis. OBJECTIVE: The aim of this study was to analyze the expression of five susceptibility genes (RSPO2, HAO1, CCDC91, RHPH9, and STK38L) for human ossification of the posterior longitudinal ligaments (OPLL) identified in a genome-wide association study. SUMMARY OF BACKGROUND DATA: Detailed expression and functional studies for the five susceptibility genes are needed to aid in clarification of the etiology and pathogenesis of OPLL. METHODS: Immunostaining, cell culture, and real-time RT-PCR were performed on ossified ligament samples collected during anterior cervical decompression for symptomatic OPLL (n = 39 patients) and on control non-OPLL samples (n = 8 patients). Immunohistochemical analysis in spinal hyperostotic mice (ttw/ttw) (n = 25) was also performed. The sample sections were stained for RSPO2, HAO1, CCDC91, RHPH9, STK38L, Runx2, Sox9, and CD90. The mRNA expression levels of the five susceptibility genes were also analyzed in cultured human OPLL and non-OPLL cells subjected to cyclic tensile strain. RESULTS: Immunoreactivity for RSPO2 and Sox9 was evident in proliferating chondrocytes in human OPLL tissues and ttw/ttw mice. Application of cyclic tensile strain to cultured human OPLL cells resulted in increases in mRNA levels for RSPO2, HAO1, and CCDC91. However, individual differences in expression in human OPLL-related samples were seen. HAO1-positive cells were detected only in 3- to 6-week-old ttw/ttw mice that did not simultaneously express RSPO2-positive samples. CONCLUSION: Among the five susceptibility genes, RSPO2, HAO1, and CCDC91 might be contributory factors in progression of OPLL. RSPO2 may be involved in endochondral ossification, especially in mixed or continuous type OPLL, HAO1 may be an initiation factor for OPLL that is rarely seen in mature human OPLL samples, and CCDC91 may be associated with progression of ossification caused by mechanical stress. These findings provide important insights into the pathogenesis and therapeutic targets for OPLL. LEVEL OF EVIDENCE: N/A.