Respiratory dysfunction in degenerative cervical myelopathy: A systematic review.

INTRODUCTION: Degenerative cervical myelopathy is a condition of symptomatic cervical spinal cord compression secondary to a range of degenerative spinal pathology. Respiratory symptoms such as shortness of breath are not uncommonly reported by people with DCM and respiratory dysfunction has been described in several DCM studies. The objective of this review was therefore to systematically synthesise the current evidence on the relationship between DCM and respiratory function.

METHODS: The review was registered on PROSPERO and adhered to PRISMA guidelines. Ovid MEDLINE and Embase were searched from inception to 14th March 2023. DCM studies reporting on any measure or outcome relating to respiratory function or disease were eligible. Reference lists of included studies and relevant reviews articles were hand searched. Title, abstract and full text screening, risk of bias and GRADE assessments were completed in duplicate. A quantitative synthesis is presented.

RESULTS: Of 1991 studies identified by literature searching, 13 met inclusion criteria: 3 cohort studies, 5 case-control studies, 1 case series and 4 case studies. Forced vital capacity (FVC), peak expiratory flow rate (PEFR) and maximal voluntary ventilation (MVV) were reported to be lower in DCM patients than controls; there was inconsistency in comparisons of forced expiratory volume in 1 s (FEV1). There was conflicting evidence on whether surgical decompression was associated with improvements in respiratory parameters and on the relationship between level of spinal cord compression and respiratory dysfunction.

CONCLUSION: DCM may be associated with respiratory dysfunction. However, consistency and quality of evidence is currently low. Further work should characterise respiratory dysfunction in DCM patients more rigorously and investigate putative mechanisms such as disruption to cervical nerve roots responsible for diaphragmatic innervation and damage to descending spinal projections from brainstem respiratory centres.