Degenerative Cervical Myelopathy: Development and Natural History [AO Spine RECODE-DCM Research Priority Number 2]

Abstract

Study Design: Narrative review. Objectives: To discuss the current understanding of the natural history of degenerative cervical myelopathy (DCM). Methods: Literature review summarizing current evidence pertaining to the natural history and risk factors of DCM. Results: DCM is a common condition in which progressive arthritic disease of the cervical spine leads to spinal cord compression resulting in a constellation of neurological symptoms, in particular upper extremity dysfunction and gait impairment. Anatomical factors including cord-canal mismatch, congenitally fused vertebrae and genetic factors may increase individuals’ risk for DCM development. Non-myelopathic spinal cord compression (NMSCC) is a common phenomenon with a prevalence of 24.2% in the healthy population, and 35.3% among individuals >60 years of age. Clinical radiculopathy and/or electrophysiological signs of cervical cord dysfunction appear to be risk factors for myelopathy development. Radiological progression of incidental Ossification of the Posterior Longitudinal Ligament (OPLL) is estimated at 18.3% over 81-months and development of myelopathy ranges between 0-61.5% (follow-up ranging from 40 to 124 months between studies) among studies. In patients with symptomatic DCM undergoing non-operative treatment, 20-62% will experience neurological deterioration within 3-6 years. Conclusion: Current estimates surrounding the natural history of DCM, particularly those individuals with mild or minimal impairment, lack precision. Clear predictors of clinical deterioration for those treated with non-operative care are yet to be identified. Future studies are needed on this topic to help improve treatment counseling and clinical prognostication.

Development of a core measurement set for research in degenerative cervical myelopathy: a study protocol (AO Spine RECODE-DCM CMS)

“…The timing of the assessment is an additional source of variation with respect to aggregating outcomes. For studies considering non-operative management due to the current uncertainty around the natural history of DCM (recognised as a critical research priority) 57 this will not be possible. However, for DCM managed operatively, the recovery profile is more stereotyped and felt amenable to standardisation measurement time points.…”

“…So far, AO Spine RECODE-DCM has established the top research priorities and agreed on a single definition and index term 4 8 21–32. It has also agreed on ‘what’ should be measured in DCM research: that is, a minimum data set, which is comprised core data elements (CDE) and a core outcome set (COS).…”

Ossification of the Posterior Longitudinal Ligament: Pathophysiology, Diagnosis, and Management

“…Nonsurgical treatment may be recommended for minimally or asymptomatic OPLL patients 1 but does not mitigate the risk of future neurologic injury. As risk of OPLL progression and myelopathy is unknown, 20 the timing of surgery for patients without notable cord compression and mild symptoms is controversial. However, notable cord compression may be an indication for surgical decompression.…”

The Natural History of Degenerative Cervical Myelopathy

“…An opposing view that DCM is a progressive disease, however, was advanced in the work of Clarke and Robinson, who published a series of 120 patients in 1956 with degenerative spinal cord compression diagnosed by myelography, autopsy, or operation in whom progressive neurological deterioration was generally seen with rare remission They noted that “the patient who had adjusted himself more successfully to his disabilities often regarded himself as improved”; a sentiment echoed in the work of Phillips, who criticized Lees and Turner’s failure to employ the use of any standardized scale to measure myelopathic disability 11,12. Most recent literature conforms to the view that neurological dysfunction from DCM, at least in a large proportion of patients, does progress; but Nouri et al13,14 point out that the largest gap in our knowledge of DCM remains a full understanding of the disease course in nonoperatively treated patients…”