Clinico-Radiographic Discordance: An Evidence-Based Commentary on the Management of Degenerative Cervical Spinal Cord Compression in the Absence of Symptoms or With Only Mild Symptoms of Myelopathy

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.

Radiological Progression of Degenerative Cervical Myelopathy in a Clinically Stable Patient: Case Report

Degenerative cervical myelopathy (DCM) is a common neurological condition, with disease progression that is both variable and difficult to predict. Here, we present a case of DCM in a gentleman in his late 60s with significant radiological disease progression without consequent change in clinical symptoms. The case serves as a reminder of an enduring medical aphorism that clinical history and examination should be prioritized above more complex data, such as imaging investigations. In addition, the case also highlights that guidelines should be contextualized within individual clinical circumstances.

Evidence-based commentary on the diagnosis, management, and further research of degenerative cervical spinal cord compression in the absence of clinical symptoms of myelopathy

Degenerative cervical myelopathy (DCM) represents the final consequence of a series of degenerative changes in the cervical spine, resulting in cervical spinal canal stenosis and mechanical stress on the cervical spinal cord. This process leads to subsequent pathophysiological processes in the spinal cord tissues. The primary mechanism of injury is degenerative compression of the cervical spinal cord, detectable by magnetic resonance imaging (MRI), serving as a hallmark for diagnosing DCM. However, the relative resilience of the cervical spinal cord to mechanical compression leads to clinical-radiological discordance, i.e., some individuals may exhibit MRI findings of DCC without the clinical signs and symptoms of myelopathy. This degenerative compression of the cervical spinal cord without clinical signs of myelopathy, potentially serving as a precursor to the development of DCM, remains a somewhat controversial topic. In this review article, we elaborate on and provide commentary on the terminology, epidemiology, natural course, diagnosis, predictive value, risks, and practical management of this condition-all of which are subjects of ongoing debate.

T1 mapping in patients with cervical spinal canal stenosis with and without decompressive surgery: A longitudinal study

BACKGROUND AND PURPOSE

Cervical spinal canal stenosis (cSCS) is a common cause of spinal impairment in the elderly. With conventional magnetic resonance imaging (MRI) suffering from various limitations, high-resolution single-shot T1 mapping has been proposed as a novel MRI technique in cSCS diagnosis. In this study, we investigated the effect of conservative and surgical treatment on spinal cord T1 relaxation times in cSCS.

METHODS

T1-mapping was performed in 54 patients with cSCS at 3 Tesla MRI at the maximum-, above and below the stenosis. Subsequently, intraindividual T1-differences (ΔT1) intrastenosis were calculated. Twenty-four patients received follow-up scans after 6 months.

RESULTS

Surgically treated patients showed higher ΔT1 at baseline (154.9 ± 81.6 vs. 95.3 ± 60.7), while absolute T1-values within the stenosis were comparable between groups (863.7 ± 89.3 milliseconds vs. 855.1 ± 62.2 milliseconds). In surgically treated patients, ΔT1 decreased inverse to stenosis severity. After 6 months, ΔT1 significantly decreased in the surgical group (154.9 ± 81.6 milliseconds to 85.7 ± 108.9 milliseconds, p = .021) and remained unchanged in conservatively treated patients. Both groups showed clinical improvement at the 6-month follow-up.

CONCLUSIONS

Baseline difference of T1 relaxation time (ΔT1) might serve as a supporting marker for treatment decision and change of T1 relaxation time might reflect relief of spinal cord narrowing indicating regenerative processes. Quantitative T1-mapping represents a promising additional imaging method to indicate a surgical treatment plan and to validate treatment success.

Comprehensive Physiotherapeutic Management of Atlas Occipitalization: A Case Report

The atlas (C1) and occipital bone at the base of the skull fuse together in atlas occipitalization, an uncommon congenital abnormality. Because it can result in cervical spine instability, nerve impingement, and related symptoms including stiffness, pain, and neurological impairments, it poses a challenging therapeutic problem. We describe the case of a female patient, 27 years old, who had gradually deteriorating neck discomfort, stiffness, and limited cervical mobility for six years prior to presentation. Her symptoms worsened over time despite conservative treatment, so more testing was necessary. Atlas occipitalization, congenital fusion at the C7 and D1 vertebrae, and other related cervical spine pathologies were identified by imaging examinations. The intricacies of atlas occipitalization and related cervical spine pathologies are highlighted in this case study, along with the diagnostic difficulties and interdisciplinary therapeutic strategy needed to address them. To improve cervical range of motion (ROM), lessen discomfort, and improve functional results, the patient underwent a thorough musculoskeletal examination and was given a customized physiotherapeutic intervention.

Early surgery compared to nonoperative management for mild degenerative cervical myelopathy: a cost-utility analysis

BACKGROUND CONTEXT

Degenerative cervical myelopathy (DCM) is a form of acquired spinal cord compression and contributes to reduced quality of life secondary to neurological dysfunction and pain. There remains uncertainty regarding optimal management for individuals with mild myelopathy. Specifically, owing to lacking long-term natural history studies in this population, we do not know whether these individuals should be treated with initial surgery or observation.

PURPOSE

We sought to perform a cost-utility analysis to examine early surgery for mild degenerative cervical myelopathy from the healthcare payer perspective.

STUDY DESIGN/SETTING

We utilized data from the prospective observational cohorts included in the Cervical Spondylotic Myelopathy AO Spine International and North America studies to determine health related quality of life estimates and clinical myelopathy outcomes.

PATIENT SAMPLE

We recruited all patients that underwent surgery for DCM enrolled in the Cervical Spondylotic Myelopathy AO Spine International and North America studies between December 2005 and January 2011.

OUTCOME MEASURES

Clinical assessment measures were obtained using the Modified Japanese Orthopedic Association scale and health-related quality of life measures were obtained using the Short Form-6D utility score at baseline (preoperative), 6 months, 12 months and 24 months postsurgery. Cost measures inflated to January 2015 values were obtained using pooled estimates from the hospital payer perspective for surgical patients.

METHODS

We employed a Markov state transition model with Monte Carlo microsimulation using a lifetime horizon to obtain an incremental cost utility ratio associated with early surgery for mild myelopathy. Parameter uncertainty was assessed through deterministic means using one-way and two-way sensitivity analyses and probabilistically using parameter estimate distributions with microsimulation (10,000 trials). Costs and utilities were discounted at 3% per annum.

RESULTS

Initial surgery for mild degenerative cervical myelopathy was associated with an incremental lifetime increase of 1.26 quality-adjusted life years (QALY) compared to observation. The associated cost incurred to the healthcare payer over a lifetime horizon was $12,894.56, resulting in a lifetime incremental cost-utility ratio of $10,250.71/QALY. Utilizing a willingness to pay threshold in keeping with the World Health Organization definition of "very cost-effective" ($54,000 CDN), the probabilistic sensitivity analysis demonstrated that 100% of cases were cost-effective.

CONCLUSIONS

Surgery compared to initial observation for mild degenerative cervical myelopathy was cost-effective from the Canadian healthcare payer perspective and was associated with lifetime gains in health-related quality of life.

Effect of Cervical Stenosis and Rate of Impact on Risk of Spinal Cord Injury During Whiplash Injury

STUDY DESIGN

Finite Element Study.

OBJECTIVE

To determine the risk of spinal cord injury with pre-existing cervical stenosis during a whiplash injury.

SUMMARY OF BACKGROUND DATA

Patients with cervical spinal stenosis are often cautioned on the potential increased risk of spinal cord injury (SCI) from minor trauma such as rear impact whiplash injuries. However, there is no consensus on the degree of canal stenosis or the rate of impact that predisposes cervical SCI from minor trauma.

METHODS

A previously validated three-dimensional finite element model of the human head-neck complex with the spinal cord and activated cervical musculature was used. Rear impact acceleration was applied at 1.8 m/s and 2.6 m/s. Progressive spinal stenosis was simulated at the C5 to C6 segment, from 14 mm to 6 mm, at 2 mm intervals of ventral disk protrusion. Spinal cord von Mises stress and maximum principal strain were extracted and normalized with respect to the 14 mm spine at each cervical spine level from C2 to C7.

RESULTS

The mean segmental range of motion was 7.3 degrees at 1.8 m/s and 9.3 degrees at 2.6 m/s. Spinal cord stress above the threshold for SCI was noted at C5 to C6 for 6 mm stenosis at 1.8 m/s and 2.6 m/s. The segment (C6-C7) inferior to the level of maximum stenosis also showed increasing stress and strain with a higher rate of impact. For 8 mm stenosis, spinal cord stress exceeded SCI thresholds only at 2.6 m/s. Spinal cord strain above SCI thresholds were only noted in the 6 mm stenosis model at 2.6 m/s.

CONCLUSION

Increased spinal stenosis and rate of impact are associated with greater magnitude and spatial distribution of spinal cord stress and strain during a whiplash injury. Spinal canal stenosis of 6 mm was associated with consistent elevation of spinal cord stress and strain above SCI thresholds at 2.6 m/s.

Assessment of Cervical Myelopathy Risk in Ossification of the Posterior Longitudinal Ligament Patients With Spinal Cord Compression Based on Segmental Dynamic Versus Static Factors

OBJECTIVE

Using segmental dynamic and static factors, we aimed to elucidate the pathogenesis and relationship between ossification of the posterior longitudinal ligament (OPLL) and the severity of cervical myelopathy.

METHODS

Retrospective analysis of 163 OPLL patients' 815 segments. Imaging was used to evaluate each segmental space available for the spinal cord (SAC), OPLL diameter, type, bone space, K-line, the C2-7 Cobb angle, each segmental range of motion (ROM), and total ROM. Magnetic resonance imaging was used to evaluate spinal cord signal intensity. Patients were divided into the myelopathy group (M group) and the without myelopathy group (WM group).

RESULTS

Minimal SAC (p = 0.043), (C2-7) Cobb angle (p = 0.004), total ROM (p = 0.013), and local ROM (p = 0.022) were evaluated as an independent predictor of myelopathy in OPLL. Different from the previous report, the M group had a straighter whole cervical spine (p < 0.001) and poorer cervical mobility (p < 0.001) compared to the WM group. Total ROM was not always a risk factor for myelopathy, as its impact depended on SAC, when SAC > 5 mm, the incidence rate of myelopathy decreased with the increase of total ROM. Lower cervical spine (C5-6, C6-7) showing increased "Bridge-Formation," along with spinal canal stenosis and segmental instability (C2-3, C3-4) in the upper cervical spine, could cause myelopathy in M group (p < 0.05).

CONCLUSION

Cervical myelopathy is linked to the OPLL's narrowest segment and its segmental motion. The hypermobility of the C2-3 and C3-4, contributes significantly to the development of myelopathy in OPLL.

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.

Could spinal cord oscillation contribute to spinal cord injury in degenerative cervical myelopathy?

Introduction

Degenerative Cervical Myelopathy [DCM] is a slow-motion spinal cord injury. Compression and dynamic compression have been considered disease hallmarks. However, this is likely an oversimplification, as compression is more commonly incidental and has only modest correlation to disease severity. MRI studies have recently suggested spinal cord oscillation could play a role.

Research question

To determine if spinal cord oscillation could contribute to spinal cord injury in degenerative cervical myelopathy.

Material and methods

A computational model of an oscillating spinal cord was developed from imaging of a healthy volunteer. Using finite element analysis, the observed implications of stress and strain, were measured in the context of a simulated disc herniation. The significance was bench marked by comparison to a more recognised dynamic injury mechanism; a flexion extension model of dynamic compression.

Results

Spinal cord oscillation altered both compressive and shear strain on the spinal cord. Following initial compression, compressive strain moves from within the spinal cord to the spinal cord surface, whilst shear strain is magnified by 0.1-0.2, depending on the amplitude of oscillation. These orders of magnitude are equivalent to a dynamic compression model.

Discussion and conclusion

Spinal cord oscillation could significantly contribute to spinal cord damage across DCM. Its repeated occurrence with every heartbeat, draws parallels to the concept of fatigue damage, which could reconcile differing theories on the origins of DCM. This remains hypothetical at this stage, and further investigations are required.

The Natural History of Degenerative Cervical Myelopathy

Degenerative cervical myelopathy (DCM) is the most frequent cause of spinal cord dysfunction and injury in the adult population and leads to significant loss of quality of life and economic impact from its associated medical care expenditures and loss of work. Surgical intervention is recommended for patients manifesting progressing neurological signs and symptoms of myelopathy, but the optimal management in individuals who have mild and clinically stable disease manifestations is controversial. Understanding the natural history of DCM is, thus, important in assessing patients and identifying those most appropriately indicated for surgical management. Despite the attempts to rigorously perform studies of the natural history of these patients, most published investigations suffer from methodological weaknesses or are underpowered to provide definitive answers. Investigations of particular patient subsets, however, provide some clinical guidance as to which patients stand most to benefit from surgery, and these may include those with lower baseline mJOA scores, evidence of segmental hypermobility, cord signal changes on MRI, abnormal somatosensory or motor-evoked potentials, or the presence of certain inflammatory markers. Clinicians should assess patients with mild myelopathy and those harboring asymptomatic cervical spinal cord compression individually when making treatment decisions and an understanding of the various factors that may influence natural history may aid in identifying those best indicated for surgery. Further investigations will likely identify how variables that affect natural history can be used in devising more precise treatment algorithms.

Predictive Nomogram for Clinical Prognosis in Cervical Spondylotic Myelopathy With Intramedullary T2-Weighted Increased Signal Intensity: A Novel Digital Tool for Patient Prognosis Education

Aims

To establish a predictive nomogram for clinical prognosis in cervical spondylotic myelopathy (CSM) with intramedullary T2-weighted increased signal intensity (ISI).

Methods

The clinical data of 680 patients with CSM with intramedullary T2-weighted ISI were retrospectively analyzed. The patients were divided into the modeling group (476) and the validation group (204) by using a random number table at a ratio of 7:3. The independent prognostic factors were screened using multivariate logistic regression analysis. The factors were subsequently incorporated into the establishment of the predictive nomogram. The area under the receiver operating characteristic (ROC) curve (AUC) was undertaken to estimate the discrimination of the predictive nomogram. The calibration curve and the Hosmer-Lemeshow test were used to assess the calibration of the predictive nomogram. The clinical usefulness of the predictive nomogram was evaluated by decision curve analysis (DCA).

Results

Based on the pre-operative Japanese Orthopedic Association (JOA) score, maximal canal compromise (MCC), and maximal spinal cord compression (MSCC), we established a predictive nomogram. The AUCs in the modeling group and validation group were 0.892 (95% CI: 0.861~0.924) and 0.885 (95% CI: 0.835~0.936), respectively, suggesting good discrimination of the nomogram. Calibration curves showed a favorable consistency between the predicted probability and the actual probability. In addition, the values of P of the Hosmer-Lemeshow were 0.253 and 0.184, respectively, suggesting good calibration of the nomogram. DCA demonstrated that the nomogram had good clinical usefulness.

Conclusion

We established and validated a predictive nomogram for the clinical prognosis in CSM with intramedullary T2-weighted ISI. This predictive nomogram could help clinicians and patients identify high-risk patients and educate them about prognosis, thereby improving the prognosis of high-risk patients.

Quantitative MR Markers in Non-Myelopathic Spinal Cord Compression: A Narrative Review

Degenerative spinal cord compression is a frequent pathological condition with increasing prevalence throughout aging. Initial non-myelopathic cervical spinal cord compression (NMDC) might progress over time into potentially irreversible degenerative cervical myelopathy (DCM). While quantitative MRI (qMRI) techniques demonstrated the ability to depict intrinsic tissue properties, longitudinal in-vivo biomarkers to identify NMDC patients who will eventually develop DCM are still missing. Thus, we aim to review the ability of qMRI techniques (such as diffusion MRI, diffusion tensor imaging (DTI), magnetization transfer (MT) imaging, and magnetic resonance spectroscopy (1H-MRS)) to serve as prognostic markers in NMDC. While DTI in NMDC patients consistently detected lower fractional anisotropy and higher mean diffusivity at compressed levels, caused by demyelination and axonal injury, MT and 1H-MRS, along with advanced and tract-specific diffusion MRI, recently revealed microstructural alterations, also rostrally pointing to Wallerian degeneration. Recent studies also disclosed a significant relationship between microstructural damage and functional deficits, as assessed by qMRI and electrophysiology, respectively. Thus, tract-specific qMRI, in combination with electrophysiology, critically extends our understanding of the underlying pathophysiology of degenerative spinal cord compression and may provide predictive markers of DCM development for accurate patient management. However, the prognostic value must be validated in longitudinal studies.

Improving Awareness Could Transform Outcomes in Degenerative Cervical Myelopathy [AO Spine RECODE-DCM Research Priority Number 1]

STUDY DESIGN

Literature Review (Narrative).

OBJECTIVE

To introduce the number one research priority for Degenerative Cervical Myelopathy (DCM): Raising Awareness.

METHODS

Raising awareness has been recognized by AO Spine RECODE-DCM as the number one research priority. This article reviews the evidence that awareness is low, the potential drivers, and why this must be addressed. Case studies of success from other diseases are also reviewed, drawing potential parallels and opportunities for DCM.

RESULTS

DCM may affect as many as 1 in 50 adults, yet few will receive a diagnosis and those that do will wait many years for it. This leads to poorer outcomes from surgery and greater disability. DCM is rarely featured in healthcare professional training programs and has received relatively little research funding (<2% of Amyotrophic Lateral Sclerosis or Multiple Sclerosis over the last 25 years). The transformation of stroke and acute coronary syndrome services, from a position of best supportive care with occasional surgery over 50 years ago, to avoidable disability today, represents transferable examples of success and potential opportunities for DCM. Central to this is raising awareness.

CONCLUSION

Despite the devastating burden on the patient, recognition across research, clinical practice, and healthcare policy are limited. DCM represents a significant unmet need that must become an international public health priority.

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.

Degenerative cervical myelopathy: Neuroradiological, neurophysiological and clinical correlations in 27 consecutive cases

•

New insight into prognostic factors for recovery of clinical function following posterior decompression for degenerative cervical myelopathy.

•

An increase of IOM amplitude of at least 50% coupled with preoperative T2-only and diffuse T2 signal changes on MRI is a positive prognostic factors for clinical improvement 6 months after surgery.

•

Clinical improvement at 6 months follow-up can be expected in patients with T1 hypo intensity if a diffuse border of the lesion on T2 images is present.

Spinal Cord Motion in Degenerative Cervical Myelopathy: The Level of the Stenotic Segment and Gender Cause Altered Pathodynamics

In degenerative cervical myelopathy (DCM), focally increased spinal cord motion has been observed for C5/C6, but whether stenoses at other cervical segments lead to similar pathodynamics and how severity of stenosis, age, and gender affect them is still unclear. We report a prospective matched-pair controlled trial on 65 DCM patients. A high-resolution 3D T2 sampling perfection with application-optimized contrasts using different flip angle evolution (SPACE) and a phase-contrast magnetic resonance imaging (MRI) sequence were performed and automatically segmented. Anatomical and spinal cord motion data were assessed per segment from C2/C3 to C7/T1. Spinal cord motion was focally increased at a level of stenosis among patients with stenosis at C4/C5 (n = 14), C5/C6 (n = 33), and C6/C7 (n = 10) (p < 0.033). Patients with stenosis at C2/C3 (n = 2) and C3/C4 (n = 6) presented a similar pattern, not reaching significance. Gender was a significant predictor of higher spinal cord dynamics among men with stenosis at C5/C6 (p = 0.048) and C6/C7 (p = 0.033). Age and severity of stenosis did not relate to spinal cord motion. Thus, the data demonstrates focally increased spinal cord motion depending on the specific level of stenosis. Gender-related effects lead to dynamic alterations among men with stenosis at C5/C6 and C6/C7. The missing relation of motion to severity of stenosis underlines a possible additive diagnostic value of spinal cord motion analysis in DCM.

Diffusion magnetic resonance imaging reveals tract-specific microstructural correlates of electrophysiological impairments in non-myelopathic and myelopathic spinal cord compression

BACKGROUND AND PURPOSE

Non-myelopathic degenerative cervical spinal cord compression (NMDC) frequently occurs throughout aging and may progress to potentially irreversible degenerative cervical myelopathy (DCM). Whereas standard clinical magnetic resonance imaging (MRI) and electrophysiological measures assess compression severity and neurological dysfunction, respectively, underlying microstructural deficits still have to be established in NMDC and DCM patients. The study aims to establish tract-specific diffusion MRI markers of electrophysiological deficits to predict the progression of asymptomatic NMDC to symptomatic DCM.

METHODS

High-resolution 3 T diffusion MRI was acquired for 103 NMDC and 21 DCM patients compared to 60 healthy controls to reveal diffusion alterations and relationships between tract-specific diffusion metrics and corresponding electrophysiological measures and compression severity. Relationship between the degree of DCM disability, assessed by the modified Japanese Orthopaedic Association scale, and tract-specific microstructural changes in DCM patients was also explored.

RESULTS

The study identified diffusion-derived abnormalities in the gray matter, dorsal and lateral tracts congruent with trans-synaptic degeneration and demyelination in chronic degenerative spinal cord compression with more profound alterations in DCM than NMDC. Diffusion metrics were affected in the C3-6 area as well as above the compression level at C3 with more profound rostral deficits in DCM than NMDC. Alterations in lateral motor and dorsal sensory tracts correlated with motor and sensory evoked potentials, respectively, whereas electromyography outcomes corresponded with gray matter microstructure. DCM disability corresponded with microstructure alteration in lateral columns.

CONCLUSIONS

Outcomes imply the necessity of high-resolution tract-specific diffusion MRI for monitoring degenerative spinal pathology in longitudinal studies.

The effect of ageing on presentation, management and outcomes in degenerative cervical myelopathy: a systematic review

OBJECTIVE

Degenerative cervical myelopathy (DCM) is a disabling neurological condition. The underlying degenerative changes are known to be more common with age, but the impact of age on clinical aspects of DCM has never been synthesised. The objective of this study is to determine whether age is a significant predictor in three domains-clinical presentation, surgical management and post-operative outcomes of DCM.

METHODS

a systematic review of the Medline and Embase databases (inception to 12 December 2019), registered with PROSPERO (CRD42019162077) and reported in accordance with preferred reporting items of systematic reviews and meta-analysis (PRISMA) guidelines, was conducted. The inclusion criteria were full text articles in English, evaluating the impact of age on clinical aspects of DCM.

RESULTS

the initial search yielded 2,420 citations, of which 206 articles were eventually included. Age was found to be a significant predictor in a variety of measures. Within the presentation domain, older patients have a worse pre-operative functional status. Within the management domain, older patients are more likely to undergo posterior surgery, with more levels decompressed. Within the outcomes domain, older patients have a worse post-operative functional status, but a similar amount of improvement in functional status. Because of heterogenous data reporting, meta-analysis was not possible.

CONCLUSION

the current evidence demonstrates that age significantly influences the presentation, management and outcomes of DCM. Although older patients have worse health at all individual timepoints, they experience the same absolute benefit from surgery as younger patients. This finding is of particular relevance when considering the eligibility of older patients for surgery.

The Prevalence of Asymptomatic and Symptomatic Spinal Cord Compression on Magnetic Resonance Imaging: A Systematic Review and Meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVES

Cervical spinal cord compression (SCC) due to degenerative changes of the spine is a frequent finding on magnetic resonance imaging (MRI). While most people remain asymptomatic, a proportion develop symptoms of degenerative cervical myelopathy (DCM). DCM is an often-progressive neurological disease that can cause quadriplegia. The epidemiology of SCC and DCM is poorly understood. We sought to estimate the prevalence of degenerative cervical SCC and DCM from cross-sectional cohorts undergoing MRI.

METHODS

We conducted a systematic review and meta-analysis of MRI reports on human subjects older than 16 years with degenerative SCC. A predetermined search strategy was used to identify relevant literature on MEDLINE. Title and abstract screenings were followed by full text screening. Data was extracted and analyzed by fixed or random-effects models.

RESULTS

The present search returned 1506 publications. Following our exclusion criteria, 19 studies were included. Subgroup analysis of 3786 individuals estimated the prevalence of asymptomatic SCC in a healthy population as 24.2% with a significantly higher prevalence of SCC in older populations compared with younger populations and American/European populations compared with Asian populations. Subgroup analysis of 1202 individuals estimated the prevalence of DCM in a healthy population as 2.3%.

CONCLUSIONS

We present the first estimates of the prevalence of asymptomatic SCC and DCM. Studies investigating the epidemiology of SCC are heterogeneous in methodology and results. These data indicate the need for more studies into the epidemiology of SCC and DCM performed with consistent methodologies.

Current surgical practice for multi-level degenerative cervical myelopathy: Findings from an international survey of spinal surgeons

Degenerative cervical myelopathy (DCM) results from compression of the cervical spine cord as a result of age related changes in the cervical spine, and affects up to 2% of adults, leading to progressive disability. Surgical decompression is the mainstay of treatment, but there remains significant variation in surgical approaches used. This survey was conducted in order to define current practice amongst spine surgeons worldwide, as a possible prelude to further studies comparing surgical approaches.

METHODS

An electronic survey was developed and piloted by the investigators using SurveyMonkey. Collected data was categorical and is presented using summary statistics. Where applicable, statistical comparisons were made using a Chi-Squared test. The level of significance for all statistical analyses was defined as p < 0.05. All analysis, including graphs was performed using R (R Studio).

RESULTS

127 surgeons, from 30 countries completed the survey; principally UK (66, 52%) and North America (15, 12%). Respondents were predominantly Neurosurgeons by training (108, 85%) of whom 84 (75%) reported Spinal Surgery as the principal part of their practice. The majority indicated they selected their surgical procedure for multi-level DCM on a case by case basis (62, 49%). Overall, a posterior approach was more popular for multi-level DCM (74, 58%). Region, speciality or annual multi-level case load did not influence this significantly. However, there was a trend for North American surgeons to be more likely to favour a posterior approach.

CONCLUSIONS

A posterior approach was favoured and more commonly used to treat multi-level DCM, in an international cohort of surgeons. Posterior techniques including laminectomy, laminectomy and fusion or laminoplasty appeared to be equally popular.

T1 Mapping Quantifies Spinal Cord Compression in Patients With Various Degrees of Cervical Spinal Canal Stenosis

Age-related degeneration of the cervical spinal column is the most common cause of spinal cord lesions. T1 mapping has been shown to indicate the grade and site of spinal cord compression in low grade spinal canal stenosis (SCS). Aim of our study was to further investigate the diagnostic potential of a novel T1 mapping method at 0.75 mm resolution and 4 s acquisition time in 31 patients with various grades of degenerative cervical SCS. T1 mapping was performed in axial sections of the stenosis as well as above and below. Included subjects received standard T2-weighted MRI of the cervical spine (including SCS-grading 0-III), electrophysiological, and clinical examination. We found that patients with cervical SCS showed a significant difference in T1 relaxation times within the stenosis (727 ± 66 ms, mean ± standard deviation) in comparison to non-stenotic segments above (854 ± 104 ms, p < 0.001) and below (893 ± 137 ms, p < 0.001). There was no difference in mean T1 in non-stenotic segments in patients (p = 0.232) or between segments in controls (p = 0.272). Mean difference of the T1 relaxation times was significantly higher in grade III stenosis (234 ± 45) vs. in grade II stenosis (176 ± 45, p = 0.037) vs. in grade I stenosis (90 ± 87 ms, p = 0.010). A higher difference in T1 relaxation time was associated with a central efferent conduction deficit. In conclusion, T1 mapping may be useful as a tool for SCS quantification in all grades of SCS, including high-grade stenosis with myelopathy signal in conventional T2-weighted imaging.

Research Inefficiency in Degenerative Cervical Myelopathy: Findings of a Systematic Review on Research Activity Over the Past 20 Years

STUDY DESIGN

Scoping review.

OBJECTIVE

To describe activity, themes and trends in degenerative cervical myelopathy (DCM) research over the past 20 years with a view to considering DCM research inefficiency.

METHODS

A systematic review of MEDLINE and Embase for "Cervical" AND "Myelopathy" was conducted following PRISMA guidelines. Full-text papers in English, exclusively studying DCM, published between January 1, 1995 and December 31, 2015 were considered eligible. Country of origin, number of papers published, number of patients studied, research theme, and year of publication were assessed. Comparison was made between developed and developing countries.

RESULTS

A total of 1485 papers and 4 117 051 patients were included. Japan published more papers (450) than any other country while the United States studied the greatest number of patients (3 674 737). Over 99.4% of papers and 78.6% of patients were from developed countries. The number of papers (r = 0.96, P < .001) and patients (r = 0.83 P < .001) studied each year increased significantly overall and for both developed (r = 0.93, P < .001; r = 0.81, P < .001) and developing countries (r = 0.90, P < .001; r = 0.87, P < .001). Surgery was the most prevalent theme (58.3% papers; 55.7% patients) for developed and developing countries. Research from developing countries showed greater thematic variability.

CONCLUSIONS

DCM research activity is increasing internationally, with surgery remaining the focus. Research output has predominantly been from developed countries; however, the rate of growth for developed and developing countries is comparable.

Degenerative Cervical Myelopathy: A Brief Review of Past Perspectives, Present Developments, and Future Directions

Degenerative cervical myelopathy (DCM) is the most common cause of spinal cord injury in developed countries; its prevalence is increasing due to the ageing of the population. DCM causes neurological dysfunction and is a significant cause of disability in the elderly. It has important negative impacts on the quality of life of those affected, as well as on their caregivers. DCM is triggered by a variety of degenerative changes in the neck, which affect one or more anatomical structures, including intervertebral discs, vertebrae, and spinal canal ligaments. These changes can also lead to structural abnormalities, leading to alterations in alignment, mobility, and stability. The principle unifying problem in this disease, regardless of the types of changes present, is injury to the spinal cord due to compression by static and/or dynamic forces. This review is partitioned into three segments that focus on key elements of the past, the present, and the future in the field, which serve to introduce the focus issue on "Degenerative Cervical Myelopathy and the Aging Spine". Emerging from this review is that tremendous progress has been made in the field, particularly in recent years, and that there are exciting possibilities for further advancements of patient care.

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.

Prevalence of anemia and its relationship with neurological status in patients undergoing surgery for degenerative cervical myelopathy and radiculopathy: A retrospective study of 2 spine centers

Both degenerative cervical myelopathy (DCM) and anemia are common among older patients, however insufficient data exists evaluating their co-occurrence and the influence of anemia on baseline neurological status. To address this, we examined a retrospective multicenter series of patients treated for DCM or radiculopathy. Myelopathy was graded using the Nurick scale. Established criteria for diagnosing abnormalities were used to identify blood abnormalities, including macrocytic and microcytic anemia. Multivariable regression was used to determine the impact of hematological anomalies on Nurick grades. In our analysis, we included 725 patients (age of 57.1 ± 11.7), of whom 398 presented with myelopathy and 327 presented with radiculopathy alone. Twenty six percent of all patients were anemic at baseline and the mean preoperative Nurick grade across all patients was 2.09 ± 1.29; mean Nurick grade amongst those with DCM was 2.98 ± 1.12. Compared to those with myelopathy, patients with radiculopathy were significantly younger (53.8 ± 11.0 vs 59.8 ± 11.6, p < 0.001) and less likely to be anemic (16.8% vs 33.7%, p < 0.0001). Nurick grading was significantly higher in myelopathy patients with anemia (3.13 ± 1.19 vs 2.91 ± 1.07, p = 0.05) and macrocytic anemia (4.00 ± 1.41 vs 2.97 ± 1.11, p = 0.04). Multivariate regression demonstrated that anemia (p < 0.001), age (p < 0.0001), and posterior surgical approach (p < 0.0001) were related to worse preoperative Nurick grade. In sum, these data suggest that anemia and degenerative cervical spine pathologies commonly co-occur. Anemia, and macrocytic anemia specifically, is associated with poorer neurological status in myelopathic patients. These data suggest anemia may influence baseline neurological status and impact surgical recovery in patients treated for DCM or radiculopathy.

Degenerative cervical myelopathy: Recent updates and future directions

Advances in patient selection, surgical techniques, and postoperative care have facilitated spine surgeons to manage complex spine cases with shorter operative times, reduced hospital stay and improved outcomes. We focus this article on a few areas which have shown maximum developments in management of degenerative cervical myelopathy and also throw a glimpse into the future ahead. Imaging modalities, surgical decision making, robotics and neuro-navigation, minimally invasive spinal surgery, motion preservation, use of biologics are few of them. Through this review article, we hope to provide the readers with an insight into the present state of art in cervical myelopathy and what the future has in store for us.

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.

Is microdiffusion imaging able to improve the detection of cervical myelopathy? Study protocol of a prospective observational trial (MIDICAM-Trial)

INTRODUCTION

The diagnosis of degenerative cervical myelopathy (DCM) is difficult in numerous patients due to the limited correlation of clinical symptoms, electrophysiology and MRI. This applies especially for early disease stages with mild symptoms or in uncertainty due to comorbidities. Conventional MRI myelopathy signs show a restricted sensitivity to clinical symptoms of at most 60%. It is desirable to select patients for surgical treatment as early as possible before irreversible neurological damage occurs. To improve treatment, a more reliable imaging is necessary. Microdiffusion imaging (MIDI) is an innovative MRI modality to depict tissue alterations within one voxel based on diffusion-weighted imaging (DWI) postprocessing. By separating the affected area into several mesoscopic compartments, pathological changes might be detected more sensitive through this subtle tissue resolution. We hypothesise, that MIDI shows myelopathic alterations more sensitive than conventional MRI and improves the correlation to functional impairment.

METHODS AND ANALYSIS

In this prospective, observational trial, 130 patients with a relevant degenerative cervical spinal stenosis receive MRI including MIDI and a standard clinical and electrophysiological assessment. Special subvoxel diffusion parameters are calculated. Clinical follow-ups are conducted after 3, 6 and with additional MRI and electrophysiology after 12 months. The primary endpoint is the sensitivity of MIDI to detect functional myelopathy defined by clinical and electrophysiological features correlated to conventional MRI myelopathy signs. Twenty healthy subjects will be included as negative control. The results will provide new insights into the development of mesoscopic spinal cord alterations in DCM associated to the clinical course. Aim is to improve the diagnostics of incipient myelopathy through this new modality.

ETHICS AND DISSEMINATION

The study protocol is approved by the Ethics Committee of the University of Freiburg (reference 261/17). The results will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

DRKS00012962.

A comparison of radiological descriptions of spinal cord compression with quantitative measures, and their role in non-specialist clinical management

INTRODUCTION

Magnetic resonance imaging (MRI) is gold-standard for investigating Degenerative Cervical Myelopathy (DCM), a disabling disease triggered by compression of the spinal cord following degenerative changes of adjacent structures. Quantifiable compression correlates poorly with disease and language describing compression in radiological reports is un-standardised.

STUDY DESIGN

Retrospective chart review.

OBJECTIVES

1) Identify terminology in radiological reporting of cord compression and elucidate relationships between language and quantitative measures 2) Evaluate language's ability to distinguish myelopathic from asymptomatic compression 3) Explore correlations between quantitative or qualitative features and symptom severity 4) Investigate the influence of quantitative and qualitative measures on surgical referrals.

METHODS

From all cervical spine MRIs conducted during one year at a tertiary centre (N = 1123), 166 patients had reported cord compression. For each spinal level deemed compressed by radiologists (N = 218), four quantitative measurements were calculated: 'Maximum Canal Compromise (MCC); 'Maximum Spinal Cord Compression' (MSCC); 'Spinal Canal Occupation Ratio' (SCOR) and 'Compression Ratio' (CR). These were compared to associated radiological reporting terminology.

RESULTS

1) Terminology in radiological reports was varied. Objective measures of compromise correlated poorly with language. "Compressed" was used for more severe cord compromise as measured by MCC (p<0.001), MSCC (p<0.001), and CR (p = 0.002). 2) Greater compromise was seen in cords with a myelopathy diagnosis across MCC (p<0.001); MSCC (p = 0.002) and CR (p<0.001). "Compress" (p<0.001) and "Flatten" (p<0.001) were used more commonly for myelopathy-diagnosis levels. 3) Measurements of cord compromise (MCC: p = 0.304; MSCC: p = 0.217; SCOR: p = 0.503; CR: p = 0.256) and descriptive terms (p = 0.591) did not correlate with i-mJOA score. 4) The only variables affecting spinal surgery referral were increased MSCC (p = 0.001) and use of 'Compressed' (p = 0.045).

CONCLUSIONS

Radiological reporting in DCM is variable and language is not fully predictive of the degree of quantitative cord compression. Additionally, terminology may influence surgical referrals.