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.

Walk and Run Test in Patients with Degenerative Compression of the Cervical Spinal Cord.

Impaired gait is one of the cardinal symptoms of degenerative cervical myelopathy (DCM) and frequently its initial presentation. Quantitative gait analysis is therefore a promising objective tool in the disclosure of early cervical cord impairment in patients with degenerative cervical compression. The aim of this cross-sectional observational cohort study was to verify whether an objective and easily-used walk and run test is capable of detecting early gait impairment in a practical proportion of non-myelopathic degenerative cervical cord compression (NMDCC) patients and of revealing any correlation with severity of disability in DCM. The study group consisted of 45 DCM patients (median age 58 years), 126 NMDCC subjects (59 years), and 100 healthy controls (HC) (55.5 years), all of whom performed a standardized 10-m walk and run test. Walking/running time/velocity, number of steps and cadence of walking/running were recorded; analysis disclosed abnormalities in 66.7% of NMDCC subjects. The DCM group exhibited significantly more pronounced abnormalities in all walk/run parameters when compared with the NMDCC group. These were apparent in 84.4% of the DCM group and correlated closely with disability as quantified by the modified Japanese Orthopaedic Association scale. A standardized 10-m walk/run test has the capacity to disclose locomotion abnormalities in NMDCC subjects who lack other clear myelopathic signs and may provide a means of classifying DCM patients according to their degree of disability.

Predictors of symptomatic myelopathy in degenerative cervical spinal cord compression.

OBJECTIVES: To update a previously established list of predictors for neurological cervical cord dysfunction in nonmyelopathic degenerative cervical cord compression (NMDCCC). MATERIAL AND METHODS: A prospective observational follow-up study was performed in a cohort of 112 consecutive NMDCCC subjects (55 women and 57 men; median age 59 years, range 40-79 years), either asymptomatic (40 subjects) or presenting with cervical radiculopathy or cervical pain (72 subjects), who had completed a follow-up of at least 2 years (median duration 3 years). Development of clinical signs of degenerative cervical myelopathy (DCM) as the main outcome was monitored and correlated with a large number of demographic, clinical, electrophysiological, and MRI parameters including diffusion tensor imaging characteristics (DTI) established at entry. RESULTS: Clinical evidence of the first signs and symptoms of DCM were found in 15 patients (13.4%). Development of DCM was associated with several parameters, including the clinical (radiculopathy, prolonged gait and run-time), electrophysiological (SEP, MEP and EMG signs of cervical cord dysfunction), and MRI (anteroposterior diameter of the cervical cord and cervical canal, cross-sectional area, compression ratio, type of compression, T2 hyperintensity). DTI parameters showed no significant predictive power. Multivariate analysis showed that radiculopathy, cross-sectional area (CSA) ≤ 70.1 mm2, and compression ratio (CR) ≤ 0.4 were the only independent significant predictors for progression into symptomatic myelopathy. CONCLUSIONS: In addition to previously described independent predictors of DCM development (radiculopathy and electrophysiological dysfunction of cervical cord), MRI parameters, namely CSA and CR, should also be considered as significant predictors for development of DCM.

Spinal Cord MR Diffusion Properties in Patients with Degenerative Cervical Cord Compression.

BACKGROUND AND PURPOSE: Diffusion tensor imaging (DTI) has previously been used as a biomarker of myelopathy in patients with degenerative cervical cord compression (DCCC). However, many factors may affect the diffusion properties of the spinal cord. This prospective study seeks to identify sources of variability in spinal cord DTI parameters in both DCCC patients and healthy subjects. METHODS: The study group included 130 patients with DCCC confirmed by magnetic resonance imaging and 71 control subjects without signs of DCCC. DTI data of the cervical spine were acquired in all subjects. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were measured at different levels of the spinal cord (SCLs). Statistical data analysis was then used to determine diffusion parameters in terms of age, sex, SCL, and spinal cord compression. RESULTS: Significant variations in FA and ADC values emerged when several spinal cord levels were mutually compared in the control group. FA values correlated significantly with age in the DCCC group and sex had a significant influence on ADC values in both groups. The two diffusion parameters in the DCCC group differed significantly between patients with clinical signs of mild-to-moderate myelopathy compared with asymptomatic patients, and correlated with measurements of spinal canal morphology. CONCLUSIONS: Diffusion parameters of the cervical spinal cord were thus shown to respond significantly to spinal cord compression, but were subject to interaction with several other factors including sex, age, and SCL. These findings may be important to the interpretation of DTI measurements in individual patients.