Study DesignSystematic review.ObjectivesThe pre-symptomatic state of Degenerative Cervical Myelopathy (DCM), wherein degenerative changes and spinal cord compression are seen without clinical findings, is poorly understood and inconsistently categorised. Clear identification may elucidate the temporality of DCM development. Therefore, a systematic assessment was undertaken of current terminology for pre-DCM states, with the objective of standardising definitions and informing an AO Spine expert position statement.MethodsMedline and Embase were searched for all studies on asymptomatic spinal compression or clinical findings preceding DCM, returning 3585 studies. After screening, 96 studies were included in the final analysis. The terminology used for pre-DCM states and their definitions were extracted, along with their frequencies or speciality/country of author in the literature.ResultsMultiple terms were used to represent pre-DCM stages, including "asymptomatic" (86 studies), "non-myelopathic" (26 studies), "without myelopathy" (15 studies), "pre-symptomatic" (9 studies) and "sub-clinical" (7 studies). "asymptomatic" was associated with the greatest inconsistency. Some defined this as patients with radiological signs of spinal degeneration with/without spinal cord compression but no clinical signs of myelopathy, whereas others used the term synonymously with healthy controls. This inconsistency is particularly challenging in clinical studies in which DCM patients are compared to those with pre-DCM states and/or healthy volunteers.ConclusionThere is substantial inconsistency in the terms used to describe pre-DCM states. There is no clear relationship between the terms used and the country or speciality of the main author. Standardised definitions for these disease states should be agreed and used in future studies.

Combined Neurosurgical and Orthopedic Spine Program Vancouver General Hospital University of British Columbia Vancouver BC Canada

Department of Neurological Surgery Thomas Jefferson University Philadelphia PA USA

Department of Neurological Surgery University of California Davis Sacramento CA USA

Department of Neurology University Hospital Brno and Masaryk University Brno Czech Republic

Department of Neurosurgery Barrow Neurological Institute Phoenix AZ United States

Department of Neurosurgery Faculty of Medicine KU Leuven Leuven Belgium

Department of Neurosurgery PGIMER Chandigarh India

Department of Neurosurgery The Newcastle Upon Tyne Hospitals NHS Foundation Trust Newcastle UK

Department of Orthopaedic Surgery and Spinal Surgery The University of Tokyo Hospital Tokyo Japan

Department of Orthopaedics University of British Columbia Vancouver BC Canada

Division of Neurosurgery Department of Clinical Neurosciences University of Cambridge Cambridge UK

Division of Neurosurgery Department of Surgery University Malaya Medical Centre Petaling Jaya Malaysia

Division of Neurosurgery Department of Surgery University of Toronto Toronto ON Canada

Division of Neurosurgery Geneva University Hospitals University of Geneva Geneva Switzerland

Division of Orthopaedic Surgery Clinica Alemana de Santiago Universidad del Desarrollo Santiago Chile

Division of Orthopaedic Surgery Hospital del Trabajador Santiago Chile

Division of Orthopaedic Surgery PGIMER Chandigarh India

School of Clinical Medicine University of Cambridge Cambridge UK

School of Health Sciences Faculty of Medicine and Health University of Sydney Sydney Australia

Spine and Orthopedics Chong Hua Hospital Cebu Philippines

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