Analysis of the spastic gait caused by cervical compression myelopathy

The value of Clinical signs in the diagnosis of Degenerative Cervical Myelopathy - A Systematic review and Meta-analysis

STUDY DESIGN

Delayed diagnosis of degenerative cervical myelopathy (DCM) is likely due to a combination of its subtle symptoms, incomplete neurological assessments by clinicians and a lack of public and professional awareness. Diagnostic criteria for DCM will likely facilitate earlier referral for definitive management.

OBJECTIVES

This systematic review aims to determine (i) the diagnostic accuracy of various clinical signs and (ii) the association between clinical signs and disease severity in DCM?

METHODS

A search was performed to identify studies on adult patients that evaluated the diagnostic accuracy of a clinical sign used for diagnosing DCM. Studies were also included if they assessed the association between the presence of a clinical sign and disease severity. The QUADAS-2 tool was used to evaluate the risk of bias of individual studies.

RESULTS

This review identified eleven studies that used a control group to evaluate the diagnostic accuracy of various signs. An additional 61 articles reported on the frequency of clinical signs in a cohort of DCM patients. The most sensitive clinical tests for diagnosing DCM were the Tromner and hyperreflexia, whereas the most specific tests were the Babinski, Tromner, clonus and inverted supinator sign. Five studies evaluated the association between the presence of various clinical signs and disease severity. There was no definite association between Hoffmann sign, Babinski sign or hyperreflexia and disease severity.

CONCLUSION

The presence of clinical signs suggesting spinal cord compression should encourage health care professionals to pursue further investigation, such as neuroimaging to either confirm or refute a diagnosis of DCM.

The Frequency of Symptoms in Patients With a Diagnosis of Degenerative Cervical Myelopathy: Results of a Scoping Review

STUDY DESIGN

Delayed diagnosis of degenerative cervical myelopathy (DCM) is associated with reduced quality of life and greater disability. Developing diagnostic criteria for DCM has been identified as a top research priority.

OBJECTIVES

This scoping review aims to address the following questions: What is the diagnostic accuracy and frequency of clinical symptoms in patients with DCM?

METHODS

A scoping review was conducted using a database of all primary DCM studies published between 2005 and 2020. Studies were included if they (i) assessed the diagnostic accuracy of a symptom using an appropriate control group or (ii) reported the frequency of a symptom in a cohort of DCM patients.

RESULTS

This review identified three studies that discussed the diagnostic accuracy of various symptoms and included a control group. An additional 58 reported on the frequency of symptoms in a cohort of patients with DCM. The most frequent and sensitive symptoms in DCM include unspecified paresthesias (86%), hand numbness (82%) and hand paresthesias (79%). Neck and/or shoulder pain was present in 51% of patients with DCM, whereas a minority had back (19%) or lower extremity pain (10%). Bladder dysfunction was uncommon (38%) although more frequent than bowel (23%) and sexual impairment (4%). Gait impairment is also commonly seen in patients with DCM (72%).

CONCLUSION

Patients with DCM present with many different symptoms, most commonly sensorimotor impairment of the upper extremities, pain, bladder dysfunction and gait disturbance. If patients present with a combination of these symptoms, further neuroimaging is indicated to confirm the diagnosis of DCM.

Gait function assessed using 3D gait analysis in patients with cervical spinal myelopathy before and after surgical decompression: a systematic review and meta-analysis

BACKGROUND

Degenerative cervical myelopathy (DCM) is the most common cause of cervical spinal cord dysfunction in adults and the result of chronic degenerative changes of the cervical spine. The compression of the spinal cord can lead to ischemia, inflammation, and neuronal apoptosis with a consequent impairment of the neurological function. Gait impairment is one of the most frequent signs of DCM.

PURPOSE

To investigate the changes in spatio-temporal gait parameters assessed using 3D gait analysis in patients affected by DCM compared with healthy controls and the effect of surgical decompression on these parameters.

STUDY DESIGN/SETTING

Systematic review and meta-analysis.

PATIENT SAMPLE

The meta-analysis included 267 patients with DCM and 276 healthy controls.

OUTCOME MEASURES

Spatio-temporal parameters of gait were assessed. The primary outcome was gait speed; the secondary outcomes were cadence, stride length, step width, stride time, single-limb support time, and double-limb support time.

METHODS

Studies reporting spatial and/or temporal gait parameters measured using 3D gait analysis in patients with DCM were included. Data sources were Embase, Medline, and the Core Collection of Web of Science. Meta-analyses were performed to investigate the influence of surgical decompression in patients measured before and after surgery as well as to compare gait parameters of patients with DCM with controls.

RESULTS

Thirteen studies reporting on 267 patients with DCM and 276 healthy controls met the inclusion criteria. Seven studies compared patients with DCM with healthy controls, three studies compared gait in patients with DCM before and after surgical decompression, and three studies performed both comparisons. Compared with healthy controls, patients with DCM had slower gait speed (Standardized Mean Difference (SMD), -1.49; 95% confidence interval (CI) [-1.86; -1.13]; p<.001), lower cadence (SMD, -0.78; 95%CI [-1.00; -0.56]; p<.001), shorter stride length (SMD, -1.27; 95%CI [-1.53, -1.01]; p<.001), greater step width (SMD, 0.98; 95%CI [0.42, 1.54]; p=.003), longer stride time (SMD, 0.77; 95%CI [0.37, 1.16]; p=.009), single-limb support phase (SMD, -0.68; 95%CI [-1.06; -0.29]; p=.011), and double-limb support phase (SMD 0.84; 95%CI [0.35, 1.32]; p=.012). After surgical decompression, patients with DCM showed an improvement in gait speed (SMD, 0.57 (95%CI [0.29; 0.85]; p=.003) and no significant differences in other spatio-temporal parameters.

CONCLUSIONS

Patients with DCM have clearly different spatio-temporal gait parameters than healthy controls. Gait speed is the only spatio-temporal gait parameter that improves significantly after surgical decompression suggesting that gait speed may be an important clinical outcome parameter in patients with DCM.

Analysis of Spastic Gait in Patients With Cervical Myelopathy Using the Timed Up and Go Test With a Laser Range Sensor

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

This study aimed to objectively evaluate spastic gait and reveal its novel characteristics via analysis of gait in patients with cervical myelopathy (CM) using the Timed Up and Go (TUG) test with a laser range sensor.

SUMMARY OF BACKGROUND DATA

Among patients with CM, spastic gait is a common diagnostic symptom; thus, objective assessments of spastic gait would be useful for the diagnosis of CM and recognition of disease status. Although spastic gait has been objectively evaluated in previous studies, the methods employed in those studies are not suitable for clinical settings.

METHODS

In total, 37 and 24 participants were recruited for a control group and CM group, respectively. CM was diagnosed by spine surgeons. We developed a laser TUG test, in which the position and velocity of both the legs were captured. The parameter values for both groups were statistically compared, and odds ratios were calculated using logistic regression analyses.

RESULTS

The total TUG-test time, time to stand up, time to first step, number of steps, and trajectory error for the CM group were significantly higher than those for the control group, whereas the average velocity and average stride length for the CM group were significantly lower than those for the control group. There was a significant independent association between the total TUG-test time and CM. The optimal cutoff point of the total test time for CM risk was approximately 9 seconds.

CONCLUSION

Through the use of the laser TUG test, we were able to identify characteristics of spastic gait, which leads to difficulty in standing and taking the first step, wobbling while walking, and an increased risk of falling. We found that the risk of CM was higher if the individual took longer than 9 seconds to complete the TUG test.Level of Evidence: 4.

Improving Assessment of Disease Severity and Strategies for Monitoring Progression in Degenerative Cervical Myelopathy [AO Spine RECODE-DCM Research Priority Number 4]

STUDY DESIGN

Narrative Review.

OBJECTIVE

To (i) discuss why assessment and monitoring of disease progression is critical in Degenerative cervical myelopathy (DCM); (ii) outline the important features of an ideal assessment tool and (iii) discuss current and novel strategies for detecting subtle deterioration in DCM.

METHODS

Literature review.

RESULTS

Degenerative cervical myelopathy is an overarching term used to describe progressive injury to the cervical spinal cord by age-related changes of the spinal axis. Based on a study by Smith et al (2020), the prevalence of DCM is approximately 2.3% and is expected to rise as the global population ages. Given the global impact of this disease, it is essential to address important knowledge gaps and prioritize areas for future investigation. As part of the AO Spine RECODE-DCM (Research Objectives and Common Data Elements for Degenerative Cervical Myelopathy) project, a priority setting partnership was initiated to increase research efficiency by identifying the top ten research priorities for DCM. One of the top ten priorities for future DCM research was: What assessment tools can be used to evaluate functional impairment, disability and quality of life in people with DCM? What instruments, tools or methods can be used or developed to monitor people with DCM for disease progression or improvement either before or after surgical treatment?

CONCLUSIONS

With the increasing prevalence of DCM, effective surveillance of this population will require both the implementation of a monitoring framework as well as the development of new assessment tools.

Epidemiological study of cervical cord compression and its clinical symptoms in community-dwelling residents

BACKGROUND

Degenerative compressive myelopathy (DCM) is caused by cervical cord compression. The relationship between the magnitude and clinical findings of cervical cord compression has been described in the literature, but the details remain unclear. This study aimed to clarify the relationship between the magnitude and clinical symptoms of cervical cord compression in community-dwelling residents.

METHODS

The present study included 532 subjects. The subjective symptoms and the objective findings of one board-certified spine surgeon were assessed. The subjective symptoms were upper extremity pain and numbness, clumsy hand, fall in the past 1 year, and subjective gait disturbance. The objective findings were: Hoffmann, Trömner, and Wartenberg signs; Babinski's and Chaddock's signs; hyperreflexia of the patellar tendon and Achilles tendon reflexes; ankle clonus; Romberg and modified Romberg tests; grip and release test; finger escape sign; and grip strength. Using midsagittal T2-weighted magnetic resonance imaging, the anterior-posterior (AP) diameters (mm) of the spinal cord at the C2 midvertebral body level (DC2) and at each intervertebral disc level from C2/3 to C7/T1 (DC2/3-C7/T1) were measured. The spinal cord compression ratio (R) for each intervertebral disc level was defined and calculated as DC2/3-C7/T1 divided by DC2. The lowest R (LR) along C2/3 to C7/T1 of each individual was divided into 3 grades by the tertile method. The relationship between LR and clinical symptoms was investigated by trend analysis.

RESULTS

The prevalence of subjective gait disturbance increased significantly with the severity of spinal cord compression (p = 0.002812), whereas the other clinical symptoms were not significantly related with the severity of spinal cord compression.

CONCLUSIONS

The magnitude of cervical cord compression had no relationship with any of the neurologic findings. However, subjective gait disturbance might be a better indicator of the possibility of early stage cervical cord compression.

Zonisamide ameliorates progression of cervical spondylotic myelopathy in a rat model

Cervical spondylotic myelopathy (CSM) is caused by chronic compression of the spinal cord and is the most common cause of myelopathy in adults. No drug is currently available to mitigate CSM. Herein, we made a rat model of CSM by epidurally implanting an expanding water-absorbent polymer underneath the laminae compress the spinal cord. The CSM rats exhibited progressive motor impairments recapitulating human CSM. CSM rats had loss of spinal motor neurons, and increased lipid peroxidation in the spinal cord. Zonisamide (ZNS) is clinically used for epilepsy and Parkinson's disease. We previously reported that ZNS protected primary spinal motor neurons against oxidative stress. We thus examined the effects of ZNS on our rat CSM model. CSM rats with daily intragastric administration of 0.5% methylcellulose (n = 11) and ZNS (30 mg/kg/day) in 0.5% methylcellulose (n = 11). Oral administration of ZNS ameliorated the progression of motor impairments, spared the number of spinal motor neurons, and preserved myelination of the pyramidal tracts. In addition, ZNS increased gene expressions of cystine/glutamate exchange transporter (xCT) and metallothionein 2A in the spinal cord in CSM rats, and also in the primary astrocytes. ZNS increased the glutathione (GSH) level in the spinal motor neurons of CSM rats. ZNS potentially ameliorates loss of the spinal motor neurons and demyelination of the pyramidal tracts in patients with CSM.

Kinematic, kinetic, and musculoskeletal modeling analysis of gait in patients with cervical myelopathy using a severity classification

BACKGROUND CONTEXT

Although a few reports have shown a change in gait motion in cervical myelopathy (CM) patients using a three-dimensional (3D) gait analysis system, there has been no detailed quantitative investigation of their gait including musculoskeletal modeling parameters. Also, 3D gait analysis using a classification of severity has not been substantiated.

PURPOSE

This study aimed to investigate kinematic, kinetic, and musculoskeletal modeling parameters of gait motion in CM patients using a severity classification.

STUDY DESIGN

Prospective cohort and cross-sectional study.

PATIENT SAMPLE

Forty-two patients with CM and 40 healthy, age-matched volunteers.

OUTCOME MEASURES

Lower extremity spatiotemporal, kinematic, kinetic, and musculoskeletal modeling parameters.

METHODS

Subjects were classified as to its severity using the Japan Orthopaedic Association score excluding the upper extremity items: group 1 (>10 points); group 2 (7-9 points); and group 3 (<6 points). A 3D motion analysis system and musculoskeletal modeling software were used to obtain the spatiotemporal, kinematic (the lower extremity joints angles in the sagittal plane), kinetic (the lower extremity joints moment and power in the sagittal plane), and musculoskeletal modeling parameters (the muscle-tendon length and velocity).

RESULTS

Genu recurvatum, deteriorated lower-extremity joint motion, and muscle-tendon velocity were observed in severe CM patients (group 3). Muscle-tendon velocities of the long head of the biceps femoris in controls and mild CM patients (groups 1 and 2) showed a bimodal waveform in the negative direction during the initial contact and preswing phases, whereas these characteristics were not present in severe CM patients (group 3).

CONCLUSIONS

The strategies of the knee joint moment during gait motion in severe CM patients were different from those of the normal gait pattern. The imbalance between agonist and antagonist muscle tissue during gait could be involved in the occurrence of genu recurvatum. It might be important for CM patients to consider improving the contraction or extension velocity of the biceps femoris muscle during each gait phase from the early stages of symptoms.

A Diagnostic Approach to Myelopathy Based on Prognostic Factors in Patients With Lower Extremity Symptoms

STUDY DESIGN

Case-control study.

OBJECTIVE

We aimed to identify predictors for latent myelopathy and to develop a diagnostic protocol based on these factors.

SUMMARY OF BACKGROUND DATA

There is no diagnostic protocol for latent myelopathy to avoid misdiagnosis in patients complaining only of lower extremity symptoms.

METHODS

This case-control study identified 791 patients discussed at conferences from April 2006 to August 2012. Overall, 460 patients complaining only of lower extremity symptoms and who underwent spine surgery were included as participants; 54 underwent surgery involving the cervical and thoracic vertebrae and were assigned to the cervical-thoracic group (C-T group); 406 underwent lumbar surgery and were assigned to the lumbar group (L group).

RESULTS

By univariate analysis, age ≥67 years, patellar tendon (PT) hyperreflexia, Achilles tendon (AT) hyperreflexia, spastic gait, and gait inability were more common in the C-T group than in the L group. By multivariate analysis, age ≥67 years (OR, 8; P = 0.001), AT hyperreflexia (OR, 20.5; P < 0.001), spastic gait (OR, 225; P < 0.001), and gait inability (OR, 64; P < 0.001) were significant predictive factors. In patients with age ≥67 years, PT hyperreflexia, and/or AT hyperreflexia, the sensitivity for myelopathy diagnosis was 98%. In patients with spastic gait or gait inability, the specificity of myelopathy diagnosis was 96%.

CONCLUSIONS

We analyzed factors that predict latent myelopathy in patients complaining only of lower extremity symptoms. We believe a diagnostic protocol based on the predictors shown in this study would contribute to the accurate diagnosis of latent myelopathy.

LEVEL OF EVIDENCE

4.

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

BACKGROUND CONTEXT

Gait impairment is a hallmark of cervical spondylotic myelopathy (CSM). It has been shown to affect quality of life but has not been well defined. Further electromyographic (EMG) characterization of the gait cycle may help elucidate the true neuromuscular pathology with implications on prognosis and rehabilitation techniques.

PURPOSE

This study compares neuromuscular activity in patients with CSM to that of healthy age-matched controls.

STUDY DESIGN

Nonrandomized, prospective, concurrent control cohort study.

METHODS

Neuromuscular activity was measured in 40 patients with symptomatic CSM during a series of over-ground gait trials at a self-selected speed before surgical intervention. External oblique, multifidus, erector spinae, rectus femoris, semitendinosus, tibialis anterior, medial gastrocnemius, and medial deltoid were assessed. Identical measurements were taken in 25 healthy control patients. Differences in time of muscle onset, peak EMG, time to peak EMG, and integrated electromyography (iEMG) were assessed using one-way ANOVA.

RESULTS

There were no significant differences between patients with CSM and healthy controls with respect to time of muscle contraction onset. Peak EMG muscle activity was significantly higher in the medial deltoid of patients with CSM (39.3% vs. 23.3% sMVC, p=.042), but no other differences were seen in the remaining muscles tested. They also demonstrated significantly longer time to peak EMG muscle activity compared with controls in 5 of the 8 muscles tested, including the multifidus (20.2 vs. 16.8 ms, p=.050), erector spinae (18.2 vs. 8.9 ms, p<.001), semitendinosis (26.3 vs. 22.4 ms, p=.037), tibialis anterior (14.7 vs. 11.0 ms, p=.050), and medial deltoid (24.2 vs. 9.2 ms, p<.001). Compared with controls, patients with CSM demonstrated significantly higher iEMG activity in the semitendinosis (586.5% vs. 272.5 sMVC, p=.047) and medial deltoid (87.62% vs. 22.5% sMVC, p=.008).

CONCLUSIONS

The onset of muscle activity is not delayed in CSM patients, but many key muscles take longer to fully contract. This produces a situation in which patients with CSM are unable to fully fire their muscles with sufficient speed to maintain a normal gait. The core and lower extremity muscles do not contract with increased peak amplitude in response, but the deltoid and hamstring muscles are more active, suggesting compensatory activity as patients attempt to maintain balance. The end result is less efficient ambulation. These findings provide a more nuanced understanding of gait in individuals suffering from CSM and may have implications on rehabilitation protocols.

Foot Tapping Test as Part of Routine Neurologic Examination in Degenerative Compression Myelopathies: A Significant Correlation between 10-sec Foot-tapping Speed and 30-m Walking Speed

Introduction

Leg spasticity in degenerative compression myelopathy causes impairment of fast and rapid repetitive movements, which tends to appear despite the disproportionate paucity of clinical weakness. As clinically useful measures used to quantify the slowness of voluntary leg movements in this pathological condition, we compared the foot tapping test (FTT) with the simple walking test, which is now considered the gold standard in this field.

Methods

We compared the FTT with the simple walking test, the grip-and-release test, and the functional scales of Nurick and the Japanese Orthopedic Association (JOA) in 77 patients with cervical compression myelopathy and 56 age-matched healthy subjects. The FTT was conducted on both sides separately, and the subject, while being seated on a chair, moved his/her toes up and down repeatedly to tap the floor as fast and as vigorously as possible for 10 sec with his/her heels planted on the floor.

Results

The number of 10-sec foot tapping in the patient group significantly correlated with the Nurick grades (r = −0.566; P < 0.0001), the JOA scores (r = 0.520; P < 0.0001), and the grip-and-release rates (r = 0.609; P < 0.0001). It also significantly correlated with the 30-m walking time (r = −0.507; P < 0.0001) and the number of steps taken (r = −0.494; P < 0.0001). Assessments of wheelchair-dependent patients and side-to-side comparison, in which the simple walking test plays no role, revealed significantly fewer FTT taps in wheelchair-bound patients than in the ambulatory patients and a significant trend for cervical compression myelopathy to dominantly affect the upper and lower limbs on the same side.

Conclusions

This study contributes to the reassessment of the currently underutilized FTT as part of a routine neurologic examination of degenerative compression myelopathy.

Analysis of spastic gait in cervical myelopathy: Linking compression ratio to spatiotemporal and pedobarographic parameters

BACKGROUND

Gait dysfunction associated with spasticity and hyperreflexia is a primary symptom in patients with compression of cervical spinal cord. The objective of this study was to link maximum compression ratio (CR) to spatiotemporal/pedobarographic parameters.

METHODS

Quantitative gait analysis was performed by using a pedobarograph in 75 elderly males with a wide range of cervical compression severity. CR values were characterized on T1-weighted magnetic resonance imaging (MRI). Statistical significances in gait analysis parameters (speed, cadence, stride length, step with, and toe-out angle) were evaluated among different CR groups by the non-parametric Kruskal-Wallis test followed by the Mann-Whitney U test using Bonferroni correction. The Spearman test was performed to verify correlations between CR and gait parameters.

RESULTS

The Kruskal-Wallis test revealed significant decline in gait speed and stride length and significant increase in toe-out angle with progression of cervical compression myelopathy. The post-hoc Mann-Whitney U test showed significant differences in these parameters between the control group (0.45<CR) and the worst myelopathy group (CR≤0.25). Cadence and step width did not significantly change with CR. On the other hand, the Spearman test revealed that CR was significantly correlated with speed, cadence, stride length, and toe-out angle.

CONCLUSION

Gait speed, stride length, and toe-out angle can serve as useful indexes for evaluating progressive gait abnormality in cervical myelopathy. Our findings suggest that CR≤0.25 is associated with significantly poorer gait performance. Nevertheless, future prospective studies are needed to determine a potential benefit from decompressive surgery in such severe compression patients.

The Role of Gait Analysis in the Evaluation of Patients with Cervical Myelopathy: A Literature Review Study

BACKGROUND

Gait analysis represents one of the newest methodologies used in the clinical evaluation of patients with cervical myelopathy (CM).

OBJECTIVE

To describe the role of gait analysis in the clinical evaluation of patients with CM, as well as its potential role in the evaluation of the functional outcome of any surgical intervention.

METHODS

A literature review was performed in the PubMed, OVID, and Google Scholar medical databases, from January 1995 to August 2016, using the terms "analysis," "anterior," "cervical myelopathy," "gait," "posterior," and "surgery." Clinical series comparing the gait patterns of patients with CM with healthy controls, as well as series evaluating gait and walk changes before and after surgical decompression, were reviewed. Case studies were excluded.

RESULTS

Nine prospective and 3 retrospective studies were found. Most of the retrieved studies showed the presence of characteristic, abnormal gait patterns among patients with CM, consisting of decreased gait speed, cadence, step length, stride length, and single-limb support time. In addition, patients with CM routinely present increased step and stride time, double-limb support time, and step width, and they have altered knee and ankle joint range of motion, compared with healthy controls. Moreover, gait and walk analysis may provide accurate functional assessment of the functional outcome of patients with CM undergoing surgical decompression.

CONCLUSIONS

Gait analysis may well be a valuable and objective tool along with other parameters in the evaluation of functionality in patients with CM, as well as in the assessment of the outcome of any surgical intervention in these patients.

Gait Analysis in Cervical Spondylotic Myelopathy

STUDY DESIGN

Gait analysis of patients with cervical spondylotic myelopathy (CSM) by using a sheet-type gait analysis system.

PURPOSE

The aim of this study was to compare the gait patterns of patients with CSM, evaluated by the Nurick grades, and to determine the threshold values of gait parameters predicting the occurrence of a fall by using a gait recorder.

OVERVIEW OF LITERATURE

Gait disorder due to CSM may progress to severe paraplegia, following even a minor trauma such as a fall. The indications for the surgery of CSM without severe paralysis remain controversial. The quantitative gait analysis and the decision for decompressive surgery in patients with CSM are important in order to prevent severe paraplegia from a fall.

METHODS

One hundred thirty-two subjects (normal, 34; CSM, 98) underwent gait analysis by using a sensor sheet. Measurements of gait cycle parameters included the step and stride length, step width, foot angle, swing phase, and stance phase. CSM was assessed by Nurick grade.

RESULTS

Although the clinical symptoms were lacking, Nurick grade 1 had significant abnormalities in the parameters of velocity, step length, and step angle (p<0.05). Regarding the Nurick grade and walking phase, the length of the stance phase was increased to more than 70% of the entire walking cycle in Nurick grade 4.

CONCLUSIONS

Gait analysis was an objective tool for evaluating the gait stability. Our results suggested that when the percentage of the stance phase in the gait cycle increases to above 70%, the CSM patients have an increased fall risk.

Electromyographic characteristics of gait impairment in cervical spondylotic myelopathy

AIM

Gait impairment in cervical spondylotic myelopathy (CSM) is characterised by a number of kinematic and kinetic abnormalities. Surface electromyography (EMG) can evaluate the contributions of individual muscles to a movement pattern and provide insight into the underlying impairments that characterise an abnormal gait. This study aimed to analyse EMG signals from major lower limb muscles in people with CSM and healthy controls during gait.

METHODS

Sixteen people with radiologically confirmed CSM and 16 matched healthy controls participated in gait analysis. Surface EMG was recorded during walking from four lower limb muscles bilaterally. The timing of muscle activation, relative amplitudes of each burst of activity and baseline activation during gait, and the muscles' responses to lengthening as a measure of spasticity were compared using previously validated methods of EMG analysis.

RESULTS

Compared to healthy controls, people with CSM had prolonged duration of activation of biceps femoris (12.5% longer) and tibialis anterior (12.4%), prolonged co-activation of rectus femoris and biceps femoris (5.14%), and impaired scaling of the amplitude of rectus femoris and biceps femoris. Muscle activation in response to lengthening was similar between groups.

CONCLUSION

The results provide evidence for paresis as a contributory factor to gait impairment in CSM, indicated by impaired amplitude and the need for proximal co-activation to compensate for lack of distal power generation. Poor proprioception may have contributed to prolonged activation of tibialis anterior. Analysis of muscle responses to lengthening suggested that spasticity was not an important contributor. These findings have implications for the assessment and rehabilitation of gait impairment in CSM.

A novel experimental model of cervical spondylotic myelopathy (CSM) to facilitate translational research

Cervical spondylotic myelopathy (CSM) is the most common form of spinal cord impairment in adults. However critical gaps in our knowledge of the pathobiology of this disease have limited therapeutic advances. To facilitate progress in the field of regenerative medicine for CSM, we have developed a unique, clinically relevant model of CSM in rats. To model CSM, a piece of synthetic aromatic polyether, to promote local calcification, was implanted microsurgically under the C6 lamina in rats. We included a sham group in which the material was removed 30s after the implantation. MRI confirmed postero-anterior cervical spinal cord compression at the C6 level. Rats modeling CSM demonstrated insidious development of a broad-based, ataxic, spastic gait, forelimb weakness and sensory changes. No neurological deficits were noted in the sham group during the course of the study. Spasticity of the lower extremities was confirmed by a significantly greater H/M ratio in CSM rats in H reflex recordings compared to sham. Rats in the compression group experienced significant gray and white matter loss, astrogliosis, anterior horn cell loss and degeneration of the corticospinal tract. Moreover, chronic progressive posterior compression of the cervical spinal cord resulted in compromise of the spinal cord microvasculature, blood-spinal cord barrier disruption, inflammation and activation of apoptotic signaling pathways in neurons and oligodendrocytes. Finally, CSM rats were successfully subjected to decompressive surgery as confirmed by MRI. In summary, this novel rat CSM model reproduces the chronic and progressive nature of human CSM, produces neurological deficits and neuropathological features accurately mimicking the human condition, is MRI compatible and importantly, allows for surgical decompression.

Effect of the number of involved spinal cord segments on gait function in patients with cervical spondylotic myelopathy

Study Design

Retrospective.

Purpose

To determine the effect of severity of cervical spondylotic myelopathy (CSM) on gait parameters according to the number of involved spinal cord segments.

Overview of Literature

Although there are a large number of studies on CSM, almost all studies have focused on hand function and only a few studies have examined the gait function in patients with CSM.

Methods

Twenty-three patients with CSM underwent magnetic resonance imaging and gait analysis. The subjects were divided into 2 groups; group I consisted of 9 patients with a single-level stenotic lesion and group II comprised 14 patients with multi-level stenotic lesions. Gait parameters were compared between the 2 groups and the normal control group.

Results

There was no significant difference in the Japanese Orthopaedic Association score between the 2 groups. Cadence, walking speed, stride length, and step length were decreased in group II compared to group I and normal control group. Peak ankle plantar flexion moments during the stance phase and peak knee flexion angle during the swing phase were decreased in group II. Peak ankle, knee, and hi p power generation during the stance phase were decreased in group II; in addition, the peak ankle power generation was decreased in group II than in the normal control group.

Conclusions

Patients with multi-level stenotic lesions had decreased gait ability compared to that in patients with a single-level stenotic lesion. The number of involved spinal cord segments can be one cause of gait deterioration in patients with CSM. Performing a gait analysis is useful for accurate evaluation of the patient.

Three-dimensional kinematic gait analysis of Doberman Pinschers with and without cervical spondylomyelopathy

BACKGROUND

The optimal treatment of cervical spondylomyelopathy (CSM) is controversial, with the owner's and clinician's perception of gait improvement often being used as outcome measures. These methods are subjective and suffer from observer bias.

OBJECTIVES

To establish kinematic gait parameters utilizing digital motion capture in normal Doberman Pinschers and compare them with CSM-affected Dobermans.

ANIMALS

Nineteen Doberman Pinschers; 10 clinically normal and 9 with CSM.

METHODS

All dogs were enrolled prospectively and fitted with a Lycra(®) body suit, and motion capture was performed and used to reconstruct a 3-D stick diagram representation of each dog based on 32 reflective markers, from which several parameters were measured. These included stride duration, length, and height; maximal and minimal spinal angles; elbow and stifle flexion and extension; and maximum and minimum distances between the thoracic and pelvic limbs. A random-effects linear regression model was used to compare parameters between groups.

RESULTS

Significant differences between groups included smaller minimum (mean = 116 mm; P = .024) and maximum (mean = 184 mm; P = .001) distance between the thoracic limbs in CSM-affected dogs. Additionally, thoracic limb stride duration was also smaller (P = .009) in CSM-affected dogs (mean = 0.7 seconds) when compared with normal dogs (mean = 0.8 seconds). In the pelvic limbs, the average stifle flexion (mean = 100°; P = .048) and extension (mean = 136°; P = .009), as well as number of strides (mean = 2.7 strides; P = .033) were different between groups.

CONCLUSIONS AND CLINICAL IMPORTANCE

Our findings suggest that computerized gait analysis reveals more consistent kinematic differences in the thoracic limbs, which can be used as future objective outcome measures.

Gait impairment in cervical spondylotic myelopathy: comparison with age- and gender-matched healthy controls

INTRODUCTION

Gait impairment is a primary symptom of cervical spondylotic myelopathy (CSM); however, little is known about specific kinetic and kinematic gait parameters. The objectives of the study were: (1) to compare gait patterns of people with untreated CSM to those of age- and gender-matched healthy controls; (2) to examine the effect of gait speed on kinematic and kinetic parameters.

MATERIALS AND METHODS

Sixteen patients with CSM were recruited consecutively from a neurosurgery clinic, and 16 healthy controls, matched to age (± 5 years) and gender, were recruited for comparison. Patients and controls underwent three-dimensional gait analysis using a Vicon(®) motion analysis system, at self-selected speed over a 10-m track. Controls were also assessed at the speed of their CSM match.

RESULTS

At self-selected speed, the CSM group walked significantly more slowly, with shorter stride lengths and longer double support duration. They showed significant decreases in several kinematic and kinetic parameters, including sagittal range of motion at the hip and knee, ankle plantarflexion, anteroposterior ground reaction force (GRF) at toe-off, power absorption at the knee in loading response and terminal stance, and power generation at the ankle. At matched speed, the CSM group showed significant decreases in knee flexion during swing, total sagittal knee range of motion, peak ankle plantarflexion and anteroposterior GRF.

CONCLUSION AND IMPLICATIONS

The findings suggested that people with CSM have significant gait abnormalities that have not been previously reported. In particular, there are key differences in the motor strategies used in the terminal stance phase of gait that cannot be explained by speed alone.

Gait analysis for evaluating the relationship between increased signal intensity on t2-weighted magnetic resonance imaging and gait function in cervical spondylotic myelopathy

OBJECTIVE

To determine relationships between increased signal intensity (ISI) on T2-weighted cervical spine magnetic resonance imaging (MRI) and parameters of gait analysis in patients with cervical spondylotic myelopathy (CSM).

DESIGN

Retrospective comparative study.

SETTING

Gait analysis laboratory.

PARTICIPANTS

Patients (N=36) who undertook cervical laminectomy or laminoplasty because of CSM.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Subjects were evaluated by using the modified Japanese Orthopaedic Association (JOA) scale, the Nurick scale, cervical spine MRI, and gait analysis. Two radiologists classified patients into 3 groups: intense, faint, and no ISI.

RESULTS

Relative to patients without ISI, those with ISI showed significantly slower gait speed, longer step time, decreased single-limb support time, increased double-limb support time, and limited range of motion of knee and ankle (P<.05). Increased intensity tended to correlate with poor gait function including slower gait speed, longer step time, decreased single-limb support time, and increased double-limb support time. The modified JOA and Nurick scale did not correlate with ISI.

CONCLUSIONS

In patients with CSM who received surgical treatment, more intense ISI on T2-weighted MRI correlated preoperatively with increased difficulties in gait function. Gait analysis may be a useful tool for evaluating gait functions in cervical myelopathy.

Intramedullary high signal intensity and neurological status as prognostic factors in cervical spondylotic myelopathy

PURPOSE

The neurological outcome of cervical spondylotic myelopathy (CSM) may depend on multiple factors, including age, symptom duration, cord compression ratio, cervical curvature, canal stenosis, and factors related to magnetic resonance (MR) signal intensity (SI). Each factor may act independently or interactively with others. To clarify the factors in prognosis, we prospectively analyzed the outcomes of patients with myelopathy caused by soft disc herniation in correlation with magnetic resonance imaging (MRI) findings and other clinical parameters.

MATERIALS AND METHODS

From June 2006 to July 2009, we performed surgical operations in 137 patients with CSM. Of these patients, 70 (51.1%), including 45 men and 25 women with ventral cord compression at one or two levels, underwent anterior cervical discectomy and fusion. The mean duration of follow-up was 32.7 months. We surveyed the cervical curvature index (CCI), canal stenosis (Torg-Pavlov ratio), cord compression ratio, the length of SI change on T2WI, and clinical outcome using the Japanese Orthopedic Association (JOA) score for cervical myelopathy. The MRI SI was evaluated by grade: grade 0, no change in signal intensity; grade 1, light signal change; and grade 2, bright signal change on the T2WI. Multifactorial effects were identified by regression analysis.

RESULTS

The mean preoperative and postoperative JOA scores were 10.5 ± 2.9 and 14.9 ± 2.1, respectively (p < 0.05). The mean recovery rate based on the JOA score was 70.0 ± 20.1%. The respective preoperative JOA scores and recovery ratios(%) were 11.6 ± 2.3 and 81.5 ± 17.0% in 20 patients with SI grade 0; 10.8 ± 2.3 and 70.1 ± 17.3% in 25 patients with grade 1; and 9.2 ± 3.6 and 60.7 ± 20.9% in 25 patients with grade 2, respectively. Post-surgical neurological outcome showed no significant relationship to age, symptom duration, cervical alignment, stenosis, or cord compression.

CONCLUSIONS

Among the variables tested, preoperative neurological status and intramedullary signal intensity were significantly related to neurological outcome. The better the preoperative neurological status was, the better the post-operative neurological outcome. The SI grade on the preoperative T2WI was negatively related to neurological outcome. Hence, the severity of SI change and preoperative neurological status emerged as significant prognostic factors in post-operative CSM.

Reliability of three-dimensional gait analysis in cervical spondylotic myelopathy

BACKGROUND

Gait impairment is one of the primary symptoms of cervical spondylotic myelopathy (CSM). Detailed assessment is possible using three-dimensional gait analysis (3DGA), however the reliability of 3DGA for this population has not been established. The aim of this study was to evaluate the test-retest reliability of temporal-spatial, kinematic and kinetic parameters in a CSM population.

METHODS

Twelve patients with CSM (mean age 54 years) were consecutively recruited from a neurosurgery clinic. 3DGA was conducted on 2 separate days, less than 1 week apart, using the VICON(®) 250 Motion Analysis. The average of 10 gait cycles was analysed. Reliability was assessed using the one-way random intraclass correlation coefficient (ICC), the standard error of measurement (SEM), and Bland-Altman limits of agreement (LOA).

RESULTS

Temporal-spatial parameters showed excellent reliability, with ICCs above 0.9 for speed, cadence, stride length, double support time, and step width. ICCs for kinematic parameters ranged from acceptable (0.62, peak knee flexion in stance) to excellent (0.95, total hip sagittal plane motion). The SEM for all kinematic parameters was below 4°, with the exception of peak hip internal rotation (5.8°). Peak values were less reliable than the total range of motion in a plane. The majority of kinetic parameters showed excellent reliability (ICCs>0.85), with the exception of peak medio-lateral ground reaction force (ICC 0.12).

CONCLUSIONS

This information will enhance the interpretation of gait scores for CSM patients, as an estimate of the change required to exceed measurement error is now available.

Recovery process following cervical laminoplasty in patients with cervical compression myelopathy: prospective cohort study

STUDY DESIGN.: Prospective cohort study. OBJECTIVE.: To investigate the recovery process after laminoplasty in patients with cervical myelopathy, and the effects of patient age and duration of symptoms before surgery on the recovery process. SUMMARY OF BACKGROUND DATA.: The surgical results of laminoplasty for cervical myelopathy have been well documented, but there have been few reports on the recovery process after cervical laminoplasty. METHODS.: The study group consisted of 98 patients who underwent double-door laminoplasty for cervical myelopathy. All cases were followed for a minimum of 5 years. The JOA score, 10 seconds grip and release test (10-second test), and grasp strength were evaluated at "fixed points" after surgery, and the recovery process in each subject was assessed. The maximum recovery time point, defined as the time point when the value just reached a plateau after surgery, was evaluated in each subject.Patients were divided into 2 groups by age (<70 years and > or = 70 years) or duration of symptoms before surgery (<1 year and > or = 1 year), and the effects of these factors on surgical results were investigated. RESULTS.: The preoperative values of all parameters significantly improved 5 years after surgery. The JOA score reached a plateau earlier (8.7 months) than did the grasp strength (21.7 months) and 10-second test (25.6 months). The maximum recovery time point of the JOA score was statistically late in the elder group (> or =70 years) compared to the younger group (<70 years). The recovery rates of the JOA score and the degree of recovery for the 10-second test in patients with symptoms lasting <1 year were statistically greater than those in patients with symptoms lasting > or =1 year. CONCLUSION.: The functional status assessed by the JOA score recovered within 1 year after surgery but further recovery can be expected up to 2 years after surgery. The comparative study suggested that patient age influenced the process of recovery, and the duration of symptoms before surgery influenced the degree of recovery.