Does Magnetic Resonance Imaging Improve the Predictive Performance of a Validated Clinical Prediction Rule Developed to Evaluate Surgical Outcome in Patients With Degenerative Cervical Myelopathy?

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 data sets 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 postsurgery was constructed using patient background, clinical symptoms, and preoperative imaging features (x-ray, CT, MRI) analyzed through 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.

Changes in cortical thickness: yet another indication of supraspinal adaptations in degenerative cervical myelopathy

This scientific commentary refers to 'Patterns of cortical thickness alterations in degenerative cervical myelopathy: associations with dexterity and gait dysfunctions', by Muhammad et al. (https://doi.org/10.1093/braincomms/fcae279).

Contemporary Practice Patterns in the Treatment of Cervical Stenosis and Central Cord Syndrome: A Survey of the Cervical Spine Research Society

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

To evaluate for areas of consensus and divergence of opinion within the spine community regarding the management of cervical spondylotic conditions and acute traumatic central cord syndrome (ATCCS) and the influence of the patient's age, disease severity, and myelomalacia.

SUMMARY OF BACKGROUND DATA

There is ongoing disagreement regarding the indications for, and urgency of, operative intervention in patients with mild degenerative myelopathy, moderate to severe radiculopathy, isolated axial symptomatology with evidence of spinal cord compression, and ATCCS without myelomalacia.

METHODS

A survey request was sent to 330 attendees of the Cervical Spine Research Society (CSRS) 2021 Annual Meeting to assess practice patterns regarding the treatment of cervical stenosis, myelopathy, radiculopathy, and ATCCS in 16 unique clinical vignettes with associated MRIs. Operative versus nonoperative treatment consensus was defined by a management option selected by >80% of survey participants.

RESULTS

Overall, 116 meeting attendees completed the survey. Consensus supported nonoperative management for elderly patients with axial neck pain and adults with axial neck pain without myelomalacia. Operative management was indicated for adult patients with mild myelopathy and myelomalacia, adult patients with severe radiculopathy, elderly patients with severe radiculopathy and myelomalacia, and elderly ATCCS patients with pre-existing myelopathic symptoms. Treatment discrepancy in favor of nonoperative management was found for adult patients with isolated axial symptomatology and myelomalacia. Treatment discrepancy favored operative management for elderly patients with mild myelopathy, adult patients with mild myelopathy without myelomalacia, elderly patients with severe radiculopathy without myelomalacia, and elderly ATCCS patients without preceding symptoms.

CONCLUSIONS

Although there is uncertainty regarding the treatment of mild myelopathy, operative intervention was favored for nonelderly patients with evidence of myelomalacia or radiculopathy and for elderly patients with ATCCS, especially if pre-injury myelopathic symptoms were present.

LEVEL OF EVIDENCE

Level V.

Associating T1-Weighted and T2-Weighted Magnetic Resonance Imaging Radiomic Signatures With Preoperative Symptom Severity in Patients With Cervical Spondylotic Myelopathy

BACKGROUND

Preoperative symptom severity in cervical spondylotic myelopathy (CSM) can be variable. Radiomic signatures could provide an imaging biomarker for symptom severity in CSM. This study utilizes radiomic signatures of T1-weighted and T2-weighted magnetic resonance imaging images to correlate with preoperative symptom severity based on modified Japanese Orthopaedic Association (mJOA) scores for patients with CSM.

METHODS

Sixty-two patients with CSM were identified. Preoperative T1-weighted and T2-weighted magnetic resonance imaging images for each patient were segmented from C2-C7. A total of 205 texture features were extracted from each volume of interest. After feature normalization, each second-order feature was further subdivided to yield a total of 400 features from each volume of interest for analysis. Supervised machine learning was used to build radiomic models.

RESULTS

The patient cohort had a median mJOA preoperative score of 13; of which, 30 patients had a score of >13 (low severity) and 32 patients had a score of ≤13 (high severity). Radiomic analysis of T2-weighted imaging resulted in 4 radiomic signatures that correlated with preoperative mJOA with a sensitivity, specificity, and accuracy of 78%, 89%, and 83%, respectively (P < 0.004). The area under the curve value for the ROC curves were 0.69, 0.70, and 0.77 for models generated by independent T1 texture features, T1 and T2 texture features in combination, and independent T2 texture features, respectively.

CONCLUSIONS

Radiomic models correlate with preoperative mJOA scores using T2 texture features in patients with CSM. This may serve as a surrogate, objective imaging biomarker to measure the preoperative functional status of patients.

The Deterioration of Cervical Kyphosis During Neck Flexion after Laminoplasty Affects the Surgical Outcome of Cervical Spondylotic Myelopathy

STUDY DESIGN

A retrospective single-center study.

OBJECTIVE

The present study investigated whether postoperative cervical alignment changes, in addition to preoperative patient backgrounds, imaging parameters, and disease severity, affect outcomes 1 year after laminoplasty.

METHODS

One hundred and three cervical spondylotic myelopathy (CSM) patients who underwent laminoplasty were enrolled. Preoperative and postoperative (1-year) Japanese Orthopedic Association (JOA) scores, cervical alignment, and balance on X-rays were assessed. Patients were classified into 2 groups for a univariate analysis according to the status of the recovery rate (RR) of the JOA score ≥50%. A multiple logistic regression analysis was performed to identify factors associated with good surgical outcomes a.

RESULTS

The mean RR of the JOA score was 47.5% and the loss of cervical lordosis in the neutral position was 5.5°. The univariate analysis revealed slight differences in age, sex, and the duration of disease. Preoperative C2-7 angles were not significantly different. The C2-7 angle during flexion after surgery was significantly smaller in Group F. In the multiple logistic regression analysis, significant factors associated with the status of RR≥50% were a younger age (OR: .75, 95%CI: .59-.96), shorter duration of disease (OR: .94, 95%CI: .89-.99), and a lordotic C2-7 angle during neck flexion after surgery (OR: 1.47, 95%CI: 1.1-1.95).

CONCLUSION

We retrospectively assessed the surgical outcomes of laminoplasty in 103 CSM cases. In addition to an older age and longer duration of disease, postoperative deteriorations in cervical kyphosis during neck flexion had a negative impact on outcomes.

The impact of phosphodiesterase inhibition on neurobehavioral outcomes in preclinical models of traumatic and non-traumatic spinal cord injury: a systematic review

Study design

Systematic review.

Objective

The objective of this study was to evaluate the impact of phosphodiesterase (PDE) inhibitors on neurobehavioral outcomes in preclinical models of traumatic and non-traumatic spinal cord injury (SCI).

Methods

A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines and was registered with PROSPERO (CRD42019150639). Searches were performed in MEDLINE and Embase. Studies were included if they evaluated the impact of PDE inhibitors on neurobehavioral outcomes in preclinical models of traumatic or non-traumatic SCI. Data were extracted from relevant studies, including sample characteristics, injury model, and neurobehavioral assessment and outcomes. Risk of bias was assessed using the SYRCLE checklist.

Results

The search yielded a total of 1,679 studies, of which 22 met inclusion criteria. Sample sizes ranged from 11 to 144 animals. PDE inhibitors used include rolipram (n = 16), cilostazol (n = 4), roflumilast (n = 1), and PDE4-I (n = 1). The injury models used were traumatic SCI (n = 18), spinal cord ischemia (n = 3), and degenerative cervical myelopathy (n = 1). The most commonly assessed outcome measures were Basso, Beattie, Bresnahan (BBB) locomotor score (n = 13), and grid walking (n = 7). Of the 22 papers that met the final inclusion criteria, 12 showed a significant improvement in neurobehavioral outcomes following the use of PDE inhibitors, four papers had mixed findings and six found PDE inhibitors to be ineffective in improving neurobehavioral recovery following an SCI. Notably, these findings were broadly consistent across different PDE inhibitors and spinal cord injury models.

Conclusion

In preclinical models of traumatic and non-traumatic SCI, the administration of PDE inhibitors appeared to be associated with statistically significant improvements in neurobehavioral outcomes in a majority of included studies. However, the evidence was inconsistent with a high risk of bias. This review provides a foundation to aid the interpretation of subsequent clinical trials of PDE inhibitors in spinal cord injury.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=150639, identifier: CRD42019150639.

Integration of MRI and somatosensory evoked potentials facilitate diagnosis of spinal cord compression

This study aimed to integrate magnetic resonance imaging (MRI) and related somatosensory evoked potential (SSEP) features to assist in the diagnosis of spinal cord compression (SCC). MRI scans were graded from 0 to 3 according to the changes in the subarachnoid space and scan signals to confirm differences in SCC levels. The amplitude, latency, and time-frequency analysis (TFA) power of preoperative SSEP features were extracted and the changes were used as standard judgments to detect neurological function changes. Then the patient distribution was quantified according to the SSEP feature changes under the same and different MRI compression grades. Significant differences were found in the amplitude and TFA power between MRI grades. We estimated three degrees of amplitude anomalies and power loss under each MRI grade and found the presence or absence of power loss occurs after abnormal changes in amplitude only. For SCC, few integrated approach combines the advantages of both MRI and evoked potentials. However, integrating the amplitude and TFA power changes of SSEP features with MRI grading can help in the diagnosis and speculate progression of SCC.

A New Framework for Investigating the Biological Basis of Degenerative Cervical Myelopathy [AO Spine RECODE-DCM Research Priority Number 5]: Mechanical Stress, Vulnerability and Time

STUDY DESIGN

Literature Review (Narrative).

OBJECTIVE

To propose a new framework, to support the investigation and understanding of the pathobiology of DCM, AO Spine RECODE-DCM research priority number 5.

METHODS

Degenerative cervical myelopathy is a common and disabling spinal cord disorder. In this perspective, we review key knowledge gaps between the clinical phenotype and our biological models. We then propose a reappraisal of the key driving forces behind DCM and an individual's susceptibility, including the proposal of a new framework.

RESULTS

Present pathobiological and mechanistic knowledge does not adequately explain the disease phenotype; why only a subset of patients with visualized cord compression show clinical myelopathy, and the amount of cord compression only weakly correlates with disability. We propose that DCM is better represented as a function of several interacting mechanical forces, such as shear, tension and compression, alongside an individual's vulnerability to spinal cord injury, influenced by factors such as age, genetics, their cardiovascular, gastrointestinal and nervous system status, and time.

CONCLUSION

Understanding the disease pathobiology is a fundamental research priority. We believe a framework of mechanical stress, vulnerability, and time may better represent the disease as a whole. Whilst this remains theoretical, we hope that at the very least it will inspire new avenues of research that better encapsulate the full spectrum of disease.

Functional MRI evidence for primary motor cortex plasticity contributes to the disease's severity and prognosis of cervical spondylotic myelopathy patients

OBJECTIVE

To investigate the brain mechanism of non-correspondence between diseases severity and compression degree of the spinal cord in cervical spondylotic myelopathy (CSM) patients and to test the utility of brain imaging biomarkers for predicting prognosis of CSM.

METHODS

We calculated voxel-wise zALFF from 54 CSM patients and 50 healthy controls using resting-state fMRI data. In analysis 1, we identified the brain regions exhibited significant differences of zALFF between CSM patients and healthy controls. In analyses 2 through 3, we investigated the zALFF differences between light-symptom CSM patients and severe-symptom CSM patients while carefully matching the degree of compression between these two groups. In analysis 4, we tested the utility of zALFF within the primary motor cortex (M1) for predicting the prognosis of CSM.

RESULTS

We found that (1) compared with the healthy controls, CSM patients exhibited higher ALFF within left M1, bilateral superior frontal gyrus, and lower zALFF within right precuneus and calcarine, suggesting altered brain neural activity in CSM patients; (2) after matching the compression degree, the CSM patients with more severe clinical symptoms exhibited higher zALFF within M1, indicating cortical function contributes to disease's severity of CSM; (3) taking the M1 zALFF as features in the prognosis prediction model improves the prediction accuracy, indicating that the M1 zALFF provide additional value for predicting the prognosis of CSM patients following decompression surgery.

CONCLUSION

The functional state of M1 contributes to the disease's severity of CSM and can provide complementary information for predicting the prognosis of CSM following decompression surgery.

KEY POINTS

• Cervical spondylotic myelopathy (CSM) patients exhibited increased zALFF within the primary motor cortex (M1), bilateral superior frontal gyrus, and decreased zALFF within the right precuneus and calcarine. • After matching the compression degree, the CSM patients with more severe clinical symptoms exhibited higher zALFF within M1, indicating cortical function contributes to disease severity of CSM. • zALFF within M1 provided additional value for predicting the prognosis of CSM patients.

Optimal machine learning methods for radiomic prediction models: Clinical application for preoperative T2*-weighted images of cervical spondylotic myelopathy

INTRODUCTION

Predicting the postoperative neurological function of cervical spondylotic myelopathy (CSM) patients is generally based on conventional magnetic resonance imaging (MRI) patterns, but this approach is not completely satisfactory. This study utilized radiomics, which produced advanced objective and quantitative indicators, and machine learning to develop, validate, test, and compare models for predicting the postoperative prognosis of CSM.

MATERIALS AND METHODS

In total, 151 CSM patients undergoing surgical treatment and preoperative MRI was retrospectively collected and divided into good/poor outcome groups based on postoperative modified Japanese Orthopedic Association (mJOA) scores. The datasets obtained from several scanners (an independent  scanner) for the training (testing) cohort were used for cross-validation (CV). Radiological models based on the intramedullary hyperintensity and compression ratio were constructed with 14 binary classifiers. Radiomic models based on 237 robust radiomic features were constructed with the same 14 binary classifiers in combination with 7 feature reduction methods, resulting in 98 models. The main outcome measures were the area under the receiver operating characteristic curve (AUROC) and accuracy.

RESULTS

Forty-one (11) radiomic models were superior to random guessing during CV (testing), with significant increased AUROC and/or accuracy (P AUROC < .05 and/or P accuracy < .05). One radiological model performed better than random guessing during CV (P accuracy < .05). In the testing cohort, the linear SVM preprocessor + SVM, the best radiomic model (AUROC: 0.74 ± 0.08, accuracy: 0.73 ± 0.07), overperformed the best radiological model (P AUROC = .048).

CONCLUSION

Radiomic features can predict postoperative spinal cord function in CSM patients. The linear SVM preprocessor + SVM has great application potential in building radiomic models.

Degenerative Cervical Myelopathy: Insights into Its Pathobiology and Molecular Mechanisms

Degenerative cervical myelopathy (DCM), earlier referred to as cervical spondylotic myelopathy (CSM), is the most common and serious neurological disorder in the elderly population caused by chronic progressive compression or irritation of the spinal cord in the neck. The clinical features of DCM include localised neck pain and functional impairment of motor function in the arms, fingers and hands. If left untreated, this can lead to significant and permanent nerve damage including paralysis and death. Despite recent advancements in understanding the DCM pathology, prognosis remains poor and little is known about the molecular mechanisms underlying its pathogenesis. Moreover, there is scant evidence for the best treatment suitable for DCM patients. Decompressive surgery remains the most effective long-term treatment for this pathology, although the decision of when to perform such a procedure remains challenging. Given the fact that the aged population in the world is continuously increasing, DCM is posing a formidable challenge that needs urgent attention. Here, in this comprehensive review, we discuss the current knowledge of DCM pathology, including epidemiology, diagnosis, natural history, pathophysiology, risk factors, molecular features and treatment options. In addition to describing different scoring and classification systems used by clinicians in diagnosing DCM, we also highlight how advanced imaging techniques are being used to study the disease process. Last but not the least, we discuss several molecular underpinnings of DCM aetiology, including the cells involved and the pathways and molecules that are hallmarks of this disease.

Clinical predictors of achieving the minimal clinically important difference after surgery for cervical spondylotic myelopathy: an external validation study from the Canadian Spine Outcomes and Research Network

OBJECTIVE

Recently identified prognostic variables among patients undergoing surgery for cervical spondylotic myelopathy (CSM) are limited to two large international data sets. To optimally inform shared clinical decision-making, the authors evaluated which preoperative clinical factors are significantly associated with improvement on the modified Japanese Orthopaedic Association (mJOA) scale by at least the minimum clinically important difference (MCID) 12 months after surgery, among patients from the Canadian Spine Outcomes and Research Network (CSORN).

METHODS

The authors performed an observational cohort study with data that were prospectively collected from CSM patients at 7 centers between 2015 and 2017. Candidate variables were tested using univariable and multiple binomial logistic regression, and multiple sensitivity analyses were performed to test assumptions about the nature of the statistical models. Validated mJOA MCIDs were implemented that varied according to baseline CSM severity.

RESULTS

Among 205 patients with CSM, there were 64 (31%) classified as mild, 86 (42%) as moderate, and 55 (27%) as severe. Overall, 52% of patients achieved MCID and the mean change in mJOA score at 12 months after surgery was 1.7 ± 2.6 points (p < 0.01), but the subgroup of patients with mild CSM did not significantly improve (mean change 0.1 ± 1.9 points, p = 0.8). Univariate analyses failed to identify significant associations between achieving MCID and sex, BMI, living status, education, smoking, disability claims, or number of comorbidities. After adjustment for potential confounders, the odds of achieving MCID were significantly reduced with older age (OR 0.7 per decade, 95% CI 0.5-0.9, p < 0.01) and higher baseline mJOA score (OR 0.8 per point, 95% CI 0.7-0.9, p < 0.01). The effects of symptom duration (OR 1.0 per additional month, 95% CI 0.9-1.0, p = 0.2) and smoking (OR 0.4, 95% CI 0.2-1.0, p = 0.06) were not statistically significant.

CONCLUSIONS

Surgery is effective at halting the progression of functional decline with CSM, and approximately half of all patients achieve the MCID. Data from the CSORN confirmed that older age is independently associated with poorer outcomes, but novel findings include that patients with milder CSM did not experience meaningful improvement, and that symptom duration and smoking were not important. These findings support a nuanced approach to shared decision-making that acknowledges some prognostic uncertainty when weighing the various risks, benefits, and alternatives to surgical treatment.

The prediction of intraoperative cervical cord function changes by different motor evoked potentials phenotypes in cervical myelopathy patients

Background

Surgery is usually the treatment of choice for patients with cervical compressive myelopathy (CCM). Motor evoked potential (MEP) has proved to be helpful tool in evaluating intraoperative cervical spinal cord function change of those patients. This study aims to describe and evaluate different MEP baseline phenotypes for predicting MEP changes during CCM surgery.

Methods

A total of 105 consecutive CCM patients underwent posterior cervical spine decompression were prospectively collected between December 2012 and November 2016. All intraoperative MEP baselines recorded before spinal cord decompression were classified into 5 types (I to V) that were carefully designed according to the different MEP parameters. The postoperative neurologic status of each patient was assessed immediately after surgery.

Results

The mean intraoperative MEP changes range were 10.2% ± 5.8, 14.7% ± 9.2, 54.8% ± 31.9, 74.1% ± 24.3, and 110% ± 40 in Type I, II, III, IV, and V, respectively. There was a significant correlation of the intraoperative MEP change rate with different MEP baseline phenotypes (r = 0.84, P < 0.01). Postoperative transient new spinal deficits were found 0/31 case in Type I, 0/21 in Type II, 1/14 in Type III, 2/24 in Type IV, and 4/15 in Type V. No permanent neurological injury was found in our cases series.

Conclusions

The MEP baselines categories for predicting intraoperative cervical cord function change is proposed through this work. The more serious the MEP baseline abnormality, the higher the probability of intraoperative MEP changes, which is beneficial to early warning for the cervical cord injury.

The Impact of Riluzole on Neurobehavioral Outcomes in Preclinical Models of Traumatic and Nontraumatic Spinal Cord Injury: Results From a Systematic Review of the Literature

STUDY DESIGN

Systematic review.

OBJECTIVE

To evaluate the impact of riluzole on neurobehavioral outcomes in preclinical models of nontraumatic and traumatic spinal cord injury (SCI).

METHODS

An extensive search of the literature was conducted in Medline, EMBASE, and Medline in Process. Studies were included if they evaluated the impact of riluzole on neurobehavioral outcomes in preclinical models of nontraumatic and traumatic SCI. Extensive data were extracted from relevant studies, including sample characteristics, injury model, outcomes assessed, timing of evaluation, and main results. The SYRCLE checklist was used to assess various sources of bias.

RESULTS

The search yielded a total of 3180 unique citations. A total of 16 studies were deemed relevant and were summarized in this review. Sample sizes ranged from 14 to 90, and injury models included traumatic SCI (n = 9), degenerative cervical myelopathy (n = 2), and spinal cord-ischemia (n = 5). The most commonly assessed outcome measures were BBB (Basso, Beattie, Besnahan) locomotor score and von Frey filament testing. In general, rats treated with riluzole exhibited significantly higher BBB locomotor scores than controls. Furthermore, riluzole significantly increased withdrawal thresholds to innocuous stimuli and tail flick latency following application of radiant heat stimuli. Finally, rats treated with riluzole achieved superior results on many components of gait assessment.

CONCLUSION

In preclinical models of traumatic and nontraumatic SCI, riluzole significantly improves locomotor scores, gait function, and neuropathic pain. This review provides the background information necessary to interpret the results of clinical trials on the impact of riluzole in traumatic and nontraumatic SCI.

Genetics of Degenerative Cervical Myelopathy: A Systematic Review and Meta-Analysis of Candidate Gene Studies

Degenerative cervical myelopathy (DCM) is estimated to be the most common cause of adult spinal cord impairment. Evidence that is suggestive of a genetic basis to DCM has been increasing over the last decade. A systematic search was conducted in MEDLINE, EMBASE, Cochrane, and HuGENet databases from their origin up to 14th December 2019 to evaluate the role of single genes in DCM in its onset, clinical phenotype, and response to surgical intervention. The initial search yielded 914 articles, with 39 articles being identified as eligible after screening. We distinguish between those contributing to spinal column deterioration and those contributing to spinal cord deterioration in assessing the evidence of genetic contributions to DCM. Evidence regarding a total of 28 candidate genes was identified. Of these, 22 were found to have an effect on the radiological onset of spinal column disease, while 12 genes had an effect on clinical onset of spinal cord disease. Polymorphisms of eight genes were found to have an effect on the radiological severity of DCM, while three genes had an effect on clinical severity. Polymorphisms of six genes were found to have an effect on clinical response to surgery in spinal cord disease. There are clear genetic effects on the development of spinal pathology, the central nervous system (CNS) response to bony pathology, the severity of both bony and cord pathology, and the subsequent response to surgical intervention. Work to disentangle the mechanisms by which the genes that are reviewed here exert their effects, as well as improved quality of evidence across diverse populations is required for further investigating the genetic contribution to DCM.

Cord compression defined by MRI is the driving factor behind the decision to operate in Degenerative Cervical Myelopathy despite poor correlation with disease severity

OBJECTIVES

The mainstay treatment for Degenerative Cervical Myelopathy (DCM) is surgical decompression. Not all cases, however, are suitable for surgery. Recent international guidelines advise surgery for moderate to severe disease as well as progressive mild disease. The goal of this study was to examine the factors in current practice that drive the decision to operate in DCM.

STUDY DESIGN

Retrospective cohort study.

METHODS

1 year of cervical spine MRI scans (N = 1123) were reviewed to identify patients with DCM with sufficient clinical documentation (N = 39). Variables at surgical assessment were recorded: age, sex, clinical signs and symptoms of DCM, disease severity, and quantitative MRI measures of cord compression. Bivariate correlations were used to compare each variable with the decision to offer the patient an operation. Subsequent multivariable analysis incorporated all significant bivariate correlations.

RESULTS

Of the 39 patients identified, 25 (64%) were offered an operation. The decision to operate was significantly associated with narrower non-pathological canal and cord diameters as well as cord compression ratio, explaining 50% of the variance. In a multivariable model, only cord compression ratio was significant (p = 0.017). Examination findings, symptoms, functional disability, disease severity, disease progression, and demographic factors were all non-significant.

CONCLUSIONS

Cord compression emerged as the main factor in surgical decision-making prior to the publication of recent guidelines. Newly identified predictors of post-operative outcome were not significantly associated with decision to operate.

Route to diagnosis of degenerative cervical myelopathy in a UK healthcare system: a retrospective cohort study

OBJECTIVES

Degenerative cervical myelopathy (DCM) presents insidiously, making initial diagnosis challenging. Surgery has been shown to prevent further disability but existing spinal cord damage may be permanent. Delays in surgery lead to increased disability and reduced postoperative improvements. Therefore, rapid surgical assessment is key to improving patient outcomes. Unfortunately, diagnosis of DCM in primary care is often delayed. This study aimed to characterise patients with DCM route to diagnosis and surgical assessment as well as to plot disease progression over time.

DESIGN

Retrospective, observational cohort study.

SETTING

Single, tertiary centre using additional clinical records from primary and secondary care centres.

PARTICIPANTS

One year of cervical MRI scans conducted at a tertiary neurosciences centre (n=1123) were screened for cervical cord compression, a corresponding clinical diagnosis of myelopathy and sufficient clinical documentation to plot a route to diagnosis (n=43).

PRIMARY OUTCOME MEASURES

Time to diagnosis from symptom onset, route to diagnosis and disease progression were the primary outcome measures in this study. Disease severity was approximated using a prospectively validated method for inferring modified Japanese Orthopaedic Association (i-mJOA) functional scoring from clinical documentation.

RESULTS

Patients received a referral to secondary care 6.4±7.7 months after symptom onset. Cervical MRI scanning and neurosurgical review occurred 12.5±13.0 and 15.8±13.5 months after symptom onset, respectively. i-mJOA was 16.0±1.7 at primary care assessment and 14.8±2.5 at surgical assessment. 61.0% of patients were offered operations. For those who received surgery, time between onset and surgery was 22.1±13.2 months.

CONCLUSIONS

Route to surgical assessment was heterogeneous and lengthy. Some patients deteriorated during this period. This study highlights the need for a streamlined pathway by which patients with cervical cord compression can receive timely assessment and treatment by a specialist. This would improve outcomes for patients using existing treatments.

Assessment of degenerative cervical myelopathy differs between specialists and may influence time to diagnosis and clinical outcomes

INTRODUCTION

Degenerative Cervical Myelopathy [DCM] often presents with non-specific symptoms and signs. It progresses insidiously and leads to permanent neurological dysfunction. Decompressive surgery can halt disease progression, however significant delays in diagnosis result in increased disability and limit recovery. The nature of early DCM symptoms is unknown, moreover it has been suggested incomplete examination contributes to missed diagnosis. This study examines how DCM is currently assessed, if assessment differs between stages of healthcare, and whether this influences patient management.

STUDY DESIGN

Retrospective cohort study.

METHODS

Cervical MRI scans (N = 1123) at a tertiary neurosciences center, over a single year, were screened for patients with DCM (N = 43). Signs, symptoms, and disease severity of DCM were extracted from patient records. Patients were considered at 3 phases of clinical assessment: primary care, secondary care, and surgical assessment.

RESULTS

Upper limb paraesthesia and urinary dysfunction were consistently the most and least prevalent symptoms respectively. Differences between assessing clinicians were present in the reporting of: limb pain (p<0.005), objective limb weakness (p = 0.01), hyperreflexia (p<0.005), Hoffmann reflex (p<0.005), extensor plantar reflex (p = 0.007), and lower limb spasticity (p<0.005). Pathological reflexes were least frequently assessed by primary care doctors.

CONCLUSION

DCM assessment varies significantly between assessors. Reporting of key features of DCM is especially low in primary care. Incomplete assessment may hinder early diagnosis and referral to spinal surgery.

Assessing structure and function of myelin in cervical spondylotic myelopathy: Evidence of demyelination

PURPOSE

To assess the extent of demyelination in cervical spondylotic myelopathy (CSM) using myelin water imaging (MWI) and electrophysiologic techniques.

METHODS

Somatosensory evoked potentials (SSEPs) and MWI were acquired in 14 patients with CSM and 18 age-matched healthy controls. MWI was performed on a 3.0T whole body magnetic resonance scanner. Myelin water fraction (MWF) was extracted for the dorsal columns and whole cord. SSEPs and MWF were also compared with conventional MRI outcomes, including T2 signal intensity, compression ratio, maximum spinal cord compression (MSCC), and maximum canal compromise (MCC).

RESULTS

Group analysis showed marked differences in T2 signal intensity, compression ratio, MSCC, and MCC between healthy controls and patients with CSM. There were no group differences in MWF and SSEP latencies. However, patients with CSM with pathologic SSEPs exhibited reduction in MWF (p < 0.05). MWF was also correlated with SSEP latencies.

CONCLUSION

Our findings provide evidence of decreased myelin content in the spinal cord associated with impaired spinal cord conduction in patients with CSM. While conventional MRI are of great value to define the extent of cord compression, they show a limited correlation with functional deficits (i.e., delayed SSEPs). MWI provides independent and complementary readouts to spinal cord compression, with a high specificity to detect impaired conduction.

Remote motor system metabolic profile and surgery outcome in cervical spondylotic myelopathy

OBJECTIVE In patients with cervical spondylotic myelopathy (CSM), the motor system may undergo progressive functional/structural changes rostral to the lesion, and these changes may be associated with clinical disability. The extent to which these changes have a prognostic value in the clinical recovery after surgical treatment is not yet known. In this study, magnetic resonance spectroscopy (MRS) was used to test 2 primary hypotheses. 1) Based on evidence of corticospinal and spinocerebellar, rubro-, or reticulospinal tract degeneration/dysfunction during chronic spinal cord compression, the authors hypothesized that the metabolic profile of the primary motor cortices (M1s) and cerebellum, respectively, would be altered in patients with CSM, and these alterations would be associated with the extent of the neurological disabilities. 2) Considering that damage and/or plasticity in the remote motor system may contribute to clinical recovery, they hypothesized that M1 and cerebellar metabolic profiles would predict, at least in part, surgical outcome. METHODS The metabolic profile, consisting of N-acetylaspartate (NAA; marker of neuronal integrity), myoinositol (glial marker), choline (cell membrane synthesis and turnover), and glutamate-glutamine (glutamatergic system), of the M1 hand/arm territory in each hemisphere and the cerebellum vermis was investigated prior to surgery in 21 patients exhibiting weakness of the upper extremities and/or gait abnormalities. Age- and sex-matched controls (n = 16) were also evaluated to estimate the pre-CSM metabolic profile of these areas. Correlation and regression analyses were performed between preoperative metabolite levels and clinical status 6 months after surgery. RESULTS Relative to controls, patients exhibited significantly higher levels of choline but no difference in the levels of other metabolites across M1s. Cerebellar metabolite levels were indistinguishable from control levels. Certain metabolites-myo-inositol and choline across M1s, NAA and glutamate-glutamine in the left M1, and myo-inositol and glutamate-glutamine in the cerebellum-were significantly associated with postoperative clinical status. These associations were greatly improved by including preoperative clinical metrics into the models. Likewise, these models improved the predictive value of preoperative clinical metrics alone. CONCLUSIONS These preliminary findings demonstrate relationships between the preoperative metabolic profiles of two remote motor areas and surgical outcome in CSM patients. Including preoperative clinical metrics in the models significantly strengthened the predictive value. Although further studies are needed, this investigation provides an important starting point to understand how the changes upstream from the injury may influence the effect of spinal cord decompression.

Clinical and Imaging Predictors of Surgical Outcome in Multilevel Cervical Ossification of Posterior Longitudinal Ligament: An Analysis of 184 Patients

OBJECTIVE

To investigate the clinical and imaging predictors of surgical outcomes in patients with ossification of the posterior longitudinal ligament (OPLL).

MATERIALS AND METHODS

From May 2010 to April 2012, a total of 200 consecutive patients with cervical OPLL were recruited for this study. Of them, 184 patients (130 men and 54 women) who could be tracked for more than 24 months after surgery were finally included for analysis. Their demographic, clinical and radiological data were collected preoperatively. The recovery ratio in terms of JOA score was used to assess the outcome of the patients preoperatively and at 2 years postoperatively. A JOA recovery rate less than 50% was considered a poor outcome.

RESULTS

Compared with good outcome group, an older mean age at operation, a longer mean duration of symptoms, a lower mean pre-operativer JOA score, and a higher proportion of diabetics were observed in poor outcome group. Patients in poor outcome group were more likely to present kyphotic cervical alignment, smaller mean transverse area of the spinal cord, and intramedullary signal abnormalities. The result of multivariate stepwise logistic regression showed that a longer duration of symptoms and the presence of T1 hypo-intensity intramedullary changes on MRI were significant risk factors of lower JOA recovery ratios.

CONCLUSION

A longer duration of symptom, T1 hypointensity on MRI and a history of minor trauma were highly predictive of a poor outcome for patients undergoing surgical treatment of OPLL. Age at operation, the history of diabetes, the preoperative JOA score, the transverse area of the spinal cord and T2 hyper-intensity on MRI were also associated with the prognosis of OPLL.