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

Allan R Martin; Sukhvinder Kalsi-Ryan; Muhammad A Akbar; Anna C Rienmueller; Jetan H Badhiwala; Jefferson R Wilson; Lindsay A Tetreault; Aria Nouri; Eric M Massicotte; Michael G Fehlings

doi:10.3171/2020.9.SPINE201395

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

J Neurosurg Spine. 2021 Apr 9;34(6):821-829. doi: 10.3171/2020.9.SPINE201395.

Authors

Allan R Martin^{1

2}, Sukhvinder Kalsi-Ryan^{3

4}, Muhammad A Akbar^{1

2}, Anna C Rienmueller², Jetan H Badhiwala¹, Jefferson R Wilson¹, Lindsay A Tetreault^{2

5}, Aria Nouri⁶, Eric M Massicotte^{1

2}, Michael G Fehlings^{1

2}

Affiliations

¹ 1Division of Neurosurgery, Department of Surgery, University of Toronto.
² 2Division of Neurosurgery, Krembil Neuroscience Centre, Toronto Western Hospital, University Health Network, Toronto.
³ 3KITE Research Institute, University Health Network, Toronto.
⁴ 4Department of Physical Therapy, University of Toronto, Ontario, Canada.
⁵ 5Graduate Entry Medicine, University College Cork, Ireland; and.
⁶ 6Department of Neurosurgery, Geneva University Hospitals, Geneva, Switzerland.

PMID: 33836502
DOI: 10.3171/2020.9.SPINE201395

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.

Keywords: degenerative cervical myelopathy; nonoperative management; outcomes.