Cervical disc degeneration: important considerations for the manual therapist

ABSTRACT

Cervical disc degeneration (CDD) is a progressive, age-related occurrence that is frequently associated with neck pain and radiculopathy. Consistent with the majority of published clinical practice guidelines (CPG) for neck pain, the 2017 American Physical Therapy Association Neck Pain CPG recommends cervical manipulation as an intervention to address acute, subacute, and chronic symptoms in the ‘Neck Pain With Mobility Deficits’ category as well for individuals with ‘Chronic Neck Pain With Radiating Pain’. While CPGs are evidence-informed statements intended to help optimize care while considering the relative risks and benefits, these guidelines generally do not discuss the mechanical consequences of underlying cervical pathology nor do they recommend specific manipulation techniques, with selection left to the practitioner’s discretion. From a biomechanical perspective, disc degeneration represents the loss of structural integrity/failure of the intervertebral disc. The sequelae of CDD include posterior neck pain, segmental hypermobility/instability, radicular symptoms, myelopathic disturbance, and potential vascular compromise. In this narrative review, we consider the mechanical, neurological, and vascular consequences of CDD, including information on the anatomy of the cervical disc and the mechanics of discogenic instability, the anatomic and mechanical basis of radiculitis, radiculopathy, changes to the intervertebral foramen, the importance of Modic changes, and the effect of spondylotic hypertrophy on the central spinal canal, spinal cord, and vertebral artery. The pathoanatomical and biomechanical consequences of CDD are discussed, along with suggestions which may enhance patient safety.

KEYWORDS:

• Cervical spine
• manual therapy
• biomechanics
• clinical decision making
• degenerative disc
• spondylosis

Implications for practice

1. Degenerative cervical segments are inherently unstable in rotation and translation and should be treated accordingly.

2. Positioning lower cervical segments in mid-range (neutral to slight flexion) during manual interventions maximizes space for neural structures without stressing degenerative tissues.

3. Traction based interventions may have less impact on CNS structures while accounting for the altered axis of rotation at the degenerative segment.

4. Reserving thrust manipulation for segments with inherently greater structural stability may enhance the safety of the intervention.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.

Notes on contributors

Brian T. Swanson

Brian T. Swanson is an Assistant Professor in the Doctor of Physical Therapy program, Department of Rehabilitation Sciences, University of Hartford, West Hartford, Connecticut.

Douglas Creighton

Douglas Creighton is an Associate Professor in the Doctor of Physical Therapy program, Human Movement Science Department, Oakland University, Rochester, Michigan.