Characterizing gait abnormalities in patients with cervical spondylotic myelopathy: a neuromuscular analysis

Differentiating Shoulder Pathology from Cervical Spine Pathology: An Algorithmic Approach

Accurate and timely diagnosis of musculoskeletal conditions is an essential component of high-quality orthopaedic care. The proximity of the shoulder to the cervical spine leads to a multitude of pathologic conditions whose clinical presentations overlap, posing a diagnostic challenge to orthopaedic providers. Missed or delayed diagnosis of the etiology for patient-described 'shoulder pain' causes frustration among patients, incurs increased healthcare costs, and delays treatment. Moreover, patients with concurrent conditions of the cervical spine and shoulder require deliberate consideration for how each condition contributes to patients' symptoms. The purpose of this review was to describe a systematic approach for evaluating and differentiating pathologies of the shoulder and cervical spine.

Degenerative cervical myelopathy: Where have we been? Where are we now? Where are we going?

Degenerative cervical myelopathy (DCM), a recently coined term, encompasses a group of age-related and genetically associated pathologies that affect the cervical spine, including cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament (OPLL). Given the significant contribution of DCM to global disease and disability, there are worldwide efforts to promote research and innovation in this area. An AO Spine effort termed 'RECODE-DCM' was initiated to create an international multistakeholder consensus group, involving patients, caregivers, physicians and researchers, to focus on launching actionable discourse on DCM. In order to improve the management, treatment and results for DCM, the RECODE-DCM consensus group recently identified ten priority areas for translational research. The current article summarizes recent advancements in the field of DCM. We first discuss the comprehensive definition recently refined by the RECODE-DCM group, including steps taken to arrive at this definition and the supporting rationale. We then provide an overview of the recent advancements in our understanding of the pathophysiology of DCM and modalities to clinically assess and diagnose DCM. A focus will be set on advanced imaging techniques that may offer the opportunity to improve characterization and diagnosis of DCM. A summary of treatment modalities, including surgical and nonoperative options, is then provided along with future neuroprotective and neuroregenerative strategies. This review concludes with final remarks pertaining to the genetics involved in DCM and the opportunity to leverage this knowledge toward a personalized medicine approach.

Remodeling of the brain correlates with gait instability in cervical spondylotic myelopathy

Introduction

Cervical spondylotic myelopathy (CSM) is a common form of non-traumatic spinal cord injury (SCI) and usually leads to remodeling of the brain and spinal cord. In CSM with gait instability, the remodeling of the brain and cervical spinal cord is unclear. We attempted to explore the remodeling of these patients' brains and spinal cords, as well as the relationship between the remodeling of the brain and spinal cord and gait instability.

Methods

According to the CSM patients' gait, we divided patients into two groups: normal gait patients (nPT) and abnormal gait patients (aPT). Voxel-wise z-score transformation amplitude of low-frequency fluctuations (zALFF) and resting-state functional connectivity (rs-FC) were performed for estimating brain changes. Cross-sectional area (CSA) and fractional anisotropy (FA) of the spinal cord were computed by Spinal cord toolbox. Correlations of these measures and the modified Japanese Orthopedic Association (mJOA) score were analyzed.

Results

We found that the zALFF of caudate nucleus in aPT was higher than that in healthy controls (HC) and lower than that in nPT. The zALFF of the right postcentral gyrus and paracentral lobule in HC was higher than those of aPT and nPT. Compared with the nPT, the aPT showed increased functional connectivity between the caudate nucleus and left angular gyrus, bilateral precuneus and bilateral posterior cingulate cortex (PCC), which constitute a vital section of the default mode network (DMN). No significantly different FA values or CSA of spinal tracts at the C2 level were observed between the HC, nPT and aPT groups. In CSM, the right paracentral lobule's zALFF was negatively correlated with the FA value of fasciculus gracilis (FCG), and the right caudate zALFF was positively correlated with the FA value of the fasciculus cuneatus (FCC). The results showed that the functional connectivity between the right caudate nucleus and DMN was negatively correlated with the CSA of the lateral corticospinal tract (CST).

Discussion

The activation of the caudate nucleus and the strengthening functional connectivity between the caudate nucleus and DMN were associated with gait instability in CSM patients. Correlations between spinal cord and brain function might be related to the clinical symptoms in CSM.

Degenerative Cervical Myelopathy: A Practical Approach to Diagnosis

STUDY DESIGN

Narrative Review.

OBJECTIVES

The objective of this review is to provide a stepwise approach to the assessment of patients with potential symptoms of degenerative cervical myelopathy (DCM).

METHODS

N/A.

RESULTS

DCM is an overarching term used to describe progressive compression of the cervical spinal cord by age-related changes to the spinal axis. These alterations to normal anatomy narrow the spinal canal, reduce the space available for the spinal cord, and may ultimately compress the ascending and descending neural tracts. Patients with DCM present with a wide range of symptoms that can significantly impact quality of life, including bilateral hand numbness and paresthesia, gait impairment, motor weakness of the upper and lower extremities, and bladder and bowel dysfunction. Unfortunately, DCM is often misdiagnosed, resulting in delayed assessment and management by the appropriate specialist. The proper evaluation of a patient with suspected DCM includes obtaining a detailed patient history, conducting a comprehensive neurological examination, and ordering appropriate tests to rule in or out other diagnoses.

CONCLUSION

This review summarizes a stepwise approach to the diagnosis of patients with DCM.

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.

Imaging and Electrophysiology for Degenerative Cervical Myelopathy [AO Spine RECODE-DCM Research Priority Number 9]

STUDY DESIGN

Narrative review.

OBJECTIVE

The current review aimed to describe the role of existing techniques and emerging methods of imaging and electrophysiology for the management of degenerative cervical myelopathy (DCM), a common and often progressive condition that causes spinal cord dysfunction and significant morbidity globally.

METHODS

A narrative review was conducted to summarize the existing literature and highlight future directions.

RESULTS

Anatomical magnetic resonance imaging (MRI) is well established in the literature as the key imaging tool to identify spinal cord compression, disc herniation/bulging, and inbuckling of the ligamentum flavum, thus facilitating surgical planning, while radiographs and computed tomography (CT) provide complimentary information. Electrophysiology techniques are primarily used to rule out competing diagnoses. However, signal change and measures of cord compression on conventional MRI have limited utility to characterize the degree of tissue injury, which may be helpful for diagnosis, prognostication, and repeated assessments to identify deterioration. Early translational studies of quantitative imaging and electrophysiology techniques show potential of these methods to more accurately reflect changes in spinal cord microstructure and function.

CONCLUSION

Currently, clinical management of DCM relies heavily on anatomical MRI, with additional contributions from radiographs, CT, and electrophysiology. Novel quantitative assessments of microstructure, perfusion, and function have the potential to transform clinical practice, but require robust validation, automation, and standardization prior to uptake.

Balance effort, Cone of Economy, and dynamic compensatory mechanisms in common degenerative spinal pathologies

BACKGROUND

Changes in balance are common in individuals with spinal disorders and may cause falls. Balance efficiency, is the ability of a person to maintain their center of gravity with minimal neuromuscular energy expenditure, oftentimes referred to as Cone of Economy (CoE). CoE balance is defined by two sets of measures taken from the center of mass (CoM) and head: 1) the range-of-sway (RoS) in the coronal and sagittal planes, and 2) the overall sway distance. This allows spine caregivers to assess the severity of a patient's balance, balance pattern, and dynamic posture and record the changes following surgical intervention. Maintenance of balance requires coordination between the central nervous and musculoskeletal systems.

RESEARCH QUESTION

To discern differences in balance effort values between common degenerative spinal pathologies and a healthy control group.

METHODS

Three-hundred and forty patients with degenerative spinal pathologies: cervical spondylotic myelopathy (CSM), adult degenerative scoliosis (ADS), sacroiliac dysfunction (SIJD), degenerative lumbar spondylolisthesis (DLS), single-level lumbar degeneration (LD), and failed back syndrome (FBS), and 40 healthy controls were recruited. A functional balance test was performed approximately one week before surgery recorded by 3D video motion capture.

RESULTS

Balance effort and compensatory mechanisms were found to be significantly greater in degenerative spinal pathologies patients compared to controls. Head and Center of Mass (CoM) overall sway ranged from 65.22 to 92.78 cm (p < 0.004) and 35.77-53.31 cm (p < 0.001), respectively in degenerative spinal pathologies patients and in comparison to controls (Head: 44.52 cm, CoM: 22.24 cm). Patients with degenerative spinal pathologies presented with greater trunk (1.61-2.98°, p < 0.038), hip (4.25-5.87°, p < 0.049), and knee (4.55-6.09°, p < 0.036) excursion when compared to controls (trunk: 0.95°, hip: 2.97°, and knee: 2.43°).

SIGNIFICANCE

The results of this study indicate that patients from a wide variety of degenerative spinal pathologies similarly exhibit markedly diminished balance (and compensatory mechanisms) as indicated by increased sway on a Romberg test and a larger Cone of Economy (CoE) as compared to healthy controls. Balance effort, as measured by overall sway, was found to be approximately double in patients with degenerative spinal pathologies compared to healthy matched controls. Clinicians can compare CoE parameters among symptomatic patients from the different cohorts using the Haddas' CoE classification system to guide their postoperative prognosis.

Fear-avoidance and Patients' Reported Outcomes are Strongly Correlated With Biomechanical Gait Parameters in Cervical Spondylotic Myelopathy Patients

STUDY DESIGN

This was a prospective cohort study.

OBJECTIVE

The aim was to explores whether fear-avoidance is associated with altered gait patterns in cervical spinal myelopathy (CSM) patients.

SUMMARY OF BACKGROUND DATA

Fear-avoidance is associated with activity restriction and emotional distress in chronic pain patients and with poorer spine surgery outcomes. In adults with spinal deformity, fear and avoidance correlates with gait pattern disruptions. Patients having CSM also display distorted gait.

METHODS

Ninety CSM patients completed the Tampa Scale for Kinesiophobia (TSK) questionnaire, and the Fear-avoidance Beliefs Questionnaire (FABQ). Each patient performed a series of gait trials. Pearson's product correlation analysis was used to determine the relationship between the self-reported fear of movement measures and the objective gait biomechanical data.

RESULTS

The TSK total score was correlated with walking speed ( P =0.003), cadence ( P =0.012), stride ( P =0.010) and step ( P =0.036) time, and stride ( P =0.018) and step ( P =0.035) length. The FABQ physical dimension was correlated with walking speed ( P <0.001), cadence ( P <0.001), stride ( P <0.001) and step ( P =0.006) time, stride ( P <0.001) and step ( P <0.001) length, and gait deviation index ( P <0.001). The FABQ work dimension was correlated with walking speed ( P =0.001), cadence ( P =0.001), stride ( P =0.001) and step ( P =0.008) time, and stride ( P =0.014) and step ( P =0.002) length.

CONCLUSIONS

These results provide a framework for further investigation of the relationship between psychosocial factors and objectively measured function in patients with CSM. This study demonstrates a strong correlation between fear and avoidance of movement, as measured with the TSK and FABQ and multiple biomechanical gait parameters, as measured with gait analysis. The current results may imply that fear and avoidance may compound and worsen functional deficits arising from CSM, and strongly suggest that fear and avoidance beliefs should be included as a component of presurgical diagnostic process for CSM patients.

Degenerative cervical myelopathy presenting as subjective lower limb weakness could be a trap towards misdiagnosis

When patients presenting with subjective lower limb weakness (SLLW) are encountered, it is natural to suspect a lumbar pathology and proceed with related clinical examination, investigations and management. However, SLLW could be a sign of degenerative cervical myelopathy (DCM) due to an evolving cord compression. In such circumstances, if symptoms are not correlated to myelopathy at the earliest, there could be potential complications over time. In this study, we intend to analyse the outcomes after surgical management of the cervical or thoracic cord compression in patients with SLLW. Retrospectively, patients who presented to our center during the years 2010–2016 with sole complaint of bilateral SLLW but radiologically diagnosed to have a solitary cervical or thoracic stenosis, or tandem spinal stenosis and underwent surgical decompression procedures were selected. Their clinical presentation was categorised into three types, myelopathy was graded using Nurick’s grading and JOA scoring; in addition, their lower limb functional status was assessed using the lower extremity functional scale (LEFS). Functional recovery following surgery was assessed at 6 weeks, 3 months, 6 months, one year, and two years. Selected patients (n = 24; Age, 56.4 ± 10.1 years; range 32–78 years) had SLLW for a period of 6.4 ± 3.2 months (range 2–13 months). Their preoperative JOA score was 11.3 ± 1.8 (range 7–15), and LEFS was 34.4 ± 7.7 (range 20–46). Radiological evidence of a solitary cervical lesion and tandem spinal stenosis was found in 6 and 18 patients respectively. Patients gradually recovered after surgical decompression with LEFS 59.8 ± 2.7 (range 56–65) at 1 year and JOA score 13.6 ± 2.7 (range − 17 to 100) at 2 years. The recovery rate at final follow up was 47.5%. Our results indicate the importance of clinically suspecting SLLW as an early non-specific sign of DCM to avoid misdiagnosis, especially in patients without conventional upper motor neuron signs. In such cases, surgical management of the cord compression resulted in significant functional recovery and halted the progression towards permanent disability.

Cervical Decompression Surgery Normalizes Gait Ground Reaction Forces in Patients With Cervical Spondylotic Myelopathy

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

Investigate the effect of surgical decompression and fusion on gait ground reaction forces (GRFs) parameters in patients with cervical spondylotic myelopathy (CSM) and to compare these values to those of healthy controls.

SUMMARY OF BACKGROUND DATA

Surgical intervention to alleviate spinal cord compression is typically recommended in cases of CSM. While the primary aim of surgery is to halt disease progression, the literature suggests that some symptomatic improvement is often observed postoperatively. Gait analysis via measurement of GRFs is a particularly sensitive means of quantifying changes in ambulatory function, but no comprehensive analysis has been published in the setting of CSM.

METHODS

Forty patients with symptomatic CSM underwent gait analysis with measurement of horizontal and vertical GRFs before and 3 months after surgery. Thirty healthy controls (H) underwent the same battery of tests. Comparisons were made between the pre- and postoperative profiles of patients with CSM as well as to that of the control group.

RESULTS

Before surgery, patients with CSM exhibited disturbances in GRF magnitudes: significantly greater maximum weight acceptance (Pre: 113.7 vs. H: 101.1% body weight [BW], P = 0.040) and push off forces (Pre: 112.2 vs. H: 101.4% BW, P = 0.044), and timing: maximum weight acceptance occurred earlier while mid-stance (Pre: 15.8 vs. H: 17.8% gait cycle [GC], P = 0.018), toe-off (Pre: 65.0 vs. H: 62.9% GC, P = 0.001), braking (Pre: 55.6 vs. H: 54.2% GC, P = 0.003), and propulsion occurred (Pre: 11.9 vs. H: 10.6% GC, P = 0.011) later compared with healthy controls. Surgery improved all GRF parameters (P < 0.039), but postoperative gait profiles did not completely normalize to levels observed in the control group.

CONCLUSION

These observations combined with published data on gait muscle activation and gait patterns in CSM patients support the idea that patients with CSM have an altered gait profile consistent with a series of poorly controlled near falls. Surgical intervention was observed to produce improvements in but not complete resolution of these gait disturbances. These data provide a more comprehensive understanding of gait in the setting of CSM.

LEVEL OF EVIDENCE

3.

The Gait Deviation Index as an indicator of gait abnormality among degenerative spinal pathologies

INTRODUCTION

The Gait Deviation Index (GDI) is a composite measure of gait abnormality derived from lower-limb joint range-of-motion which is increasingly being reported for clinical gait analysis among neurologic and orthopedic patients. A GDI score of 100 is representative of healthy individuals and decreasing scores represent a greater abnormality. Preliminary data is needed to help assess the utility of GDI as a measure of compromised gait among spine patients and to provide reference values for commonly treated pathologies.

METHODS

GDI scores were obtained from healthy adults and four symptomatic degeneration groups: cervical spondylotic myelopathy (CSM), adult degenerative scoliosis (ADS), and single-level lumbar degeneration (LD). Clinical gait analysis was done using a three-dimensional motion tracking system. Evaluations were done 1 week prior to surgical intervention for degeneration groups. Two-sample t-tests were used to compare degenerative cohorts to healthy controls and for inter-cohort comparisons. Pearson correlations were used to test for significant relationships between GDI and walking speed.

RESULTS

Degenerative cohorts all showed significantly lower (worse) GDI scores compared to healthy (all p < 0.001). CSM patients showed the best GDI scores with an average of 90, and LD patients showed the worst GDI scores with an average of 86. Worsening GDI significantly correlated with decreased walking speed among ADS patients.

CONCLUSION

Composite metrics like GDI provide a tempting means to summarize nuanced and complex gait characteristics into a single, comparable value among cohorts. The results of this study provide preliminary GDI scores for common degenerative spine pathologies. These slides can be retrieved under Electronic Supplementary Material.