Clinical outcomes of nonoperatively managed degenerative cervical myelopathy: an ambispective longitudinal cohort study in 117 patients

Abstract

OBJECTIVE Degenerative cervical myelopathy (DCM) is among the most common pathologies affecting the spinal cord but its natural history is poorly characterized. The purpose of this study was to investigate functional outcomes in patients with DCM who were managed nonoperatively as well as the utility of quantitative clinical measures and MRI to detect deterioration. METHODS Patients with newly diagnosed DCM or recurrent myelopathic symptoms after previous surgery who were initially managed nonoperatively were included. Retrospective chart reviews were performed to analyze clinical outcomes and anatomical MRI scans for worsening compression or increased signal change. Quantitative neurological assessments were collected prospectively, including modified Japanese Orthopaedic Association (mJOA) score; Quick-DASH; graded redefined assessment of strength, sensation, and prehension–myelopathy version (GRASSP–M: motor, sensory, and dexterity); grip dynamometer; Berg balance scale score; gait stability ratio; and gait variability index. A deterioration of 10% was considered significant (e.g., a 2-point decrease in mJOA score). RESULTS A total of 117 patients were included (95 newly diagnosed, 22 recurrent myelopathy), including 74 mild, 28 moderate, and 15 severe cases. Over a mean follow-up of 2.5 years, 57% (95% CI 46%–67%) of newly diagnosed patients and 73% (95% CI 50%–88%) of patients with recurrent DCM deteriorated neurologically. Deterioration was best detected with grip strength (60%), GRASSP dexterity (60%), and gait stability ratio (50%), whereas the mJOA score had low sensitivity (33%) in 50 patients. A composite score had a sensitivity of 81% and a specificity of 82%. The sensitivity of anatomical MRI was 28% (83 patients). CONCLUSIONS DCM appears to have a poor natural history; however, prospective studies are needed for validation. Serial assessments should include mJOA score, grip strength, dexterity, balance, and gait analysis. The absence of worsening on anatomical MRI or in mJOA scores is not sufficient to determine clinical stability.

Degenerative Cervical Myelopathy: Clinical Presentation, Assessment, and Natural History

“…Each of the proposed scales provides another aspect of assessment and means to follow patients both pre and postoperatively. However, in general, it is believed that DCM is reasonably well followed with the mJOA in conjunction with objective testing of DCM patients with examination of myelopathic signs and objective measures of grip strength, dexterity, balance, and gait [31,32]. As such, most recommendations for determining severity of DCM in patients and clinical decision making primarily utilize mJOA.…”

“…Martin et al suggested that the primary purpose of MRI in DCM is to establish the diagnosis and for surgical planning. In their longitudinal study of DCM patients, MRI had a sensitivity of only 28% in detecting clinical deterioration of DCM and should not be relied upon as a measure to follow DCM patients [32]. Martin et al suggested that the primary purpose of MRI in DCM is to establish the diagnosis and for surgical planning.…”

“…The deterioration occurred with mild, moderate, and severe cases of DCM. The authors concluded that DCM appears to have a poor natural history and serial assessment by a battery of tests assessing for grip strength, dexterity, balance, and gait, in addition to the mJOA, in order to detect clinical deterioration where surgery would be indicated [32].…”

Tracking White and Gray Matter Degeneration along the Spinal Cord Axis in Degenerative Cervical Myelopathy

“…Indeed, recent work suggests that >50% of patients with mild-moderate DCM will decline over a 2.5year follow-up period and that conventional magnetic resonance imaging (MRI) techniques are insensitive to detect this change. 8 Quantitative MRI (qMRI) techniques can provide biomarkers sensitive to spinal cord tissue integrity 9 and underlying pathology in DCM 7,10 and help in clinical decision making (i.e., early surgery vs. conservative treatment).…”

How Is Spinal Cord Function Measured in Degenerative Cervical Myelopathy? A Systematic Review

“…The reliance on these outcome measures has increased to the point that clinical practice guidelines (CPGs) published by AOSpine are based on the mJOA alone, recommending surgery for moderate-severe cases and mild cases that show progressive deterioration [ 4 ]. However, reliance on the mJOA is problematic in several ways, as scores can be affected by other medical conditions, interobserver reliability is limited [ 5 , 6 ], and it remains unclear how to best assess patients for neurological deterioration, although comprehensive clinical assessments and quantitative microstructural MRI have been proposed [ 7 , 8 ].…”