Cervical Pain and Disability – Part One

Patients report widely diverging levels of disability and pain in response to neck problems, with some have almost no disability and little pain and others with severe interference with normal life and high pain report. There may be different neurological and pathological events which underlie this variety which reflect the neck syndrome present. Initially most work was on finding an anatomical site of injury or damage to explain the symptoms but this has led to limited success in explaining the clinical syndromes. The pain mechanisms which may be responsible for the reported symptoms are now increasingly investigated.

The first step towards targeting more specific and accurate e.g. whiplash treatment at someone with neck pain is to understand which neck pain syndrome is dominant in the patient’s presentation. Repetitive minor events, sustained postural stresses or a defined incident such as a whiplash injury may all contribute to trauma suffered by the neck. If inflammatory changes are present due to these factors then this is understood to have profound effects on the way pain is processed in the local area of tissue damage and in the spinal cord and brain, the central nervous system. Animal research work provides most evidence but can be interpreted to understand human pain.

The central nervous system can be pushed into a state of heightened sensitivity and overreact to incoming stimuli as a result of the chain reaction caused by the injury in the locally injured part and in the spinal cord and brain. On investigation of patients with whiplash syndrome and also with more non-specific neck pain the presence of a reduced pain threshold and a reduced pain tolerance has been established. Hyperalgesia is the medical term for this increase in pain response to a normally painful stimulus.

All whiplash injuries, whatever their severity, show some degree of hyperalgesia, but those who have mild symptoms or recover completely show a decrease over 2 or 3 months. In patients with chronic and with more severe pain presentation this hyperalgesia persists. As whiplash patients are known to exhibit damaged neck and head structures after their injury, this could cause localised areas of sensitisation. A second explanation is that there has been sensitisation of the central nervous system which then overreacts to incoming stimuli, interpreting them as pain and being responsible for pain maintenance.

The internal nerve mechanisms of the central nervous system are very likely important in neck pain problems but there is evidence of ongoing pain sources in the shape of damaged neck structures. Investigation of the facet joints of the neck by injection blocks has indicated they are a pain source in some chronic whiplash pain patients. Referred pain is also a typical phenomenon, with pain being perceived away from the site of its generation. This may be because the nervous system interprets pain inputs from bodily structures such as joints and discs as related to other areas linked with the same sensory nerve pathways.

Head pain can be referred from the upper neck segments of the third cervical vertebra and above, with arm pain potentially referred from those segments below this level and down to the first thoracic vertebra. Even in parts of the body where the patient is not complaining of any symptoms there may be evidence of a heightened pain response on testing. Both patients with general neck pain and whiplash may exhibit a hyperalgesic response to incoming stimuli. There may be a more involved upset in neurological functioning in the whiplash groups with overreaction to heat, cold and pressure.

If there is greater pain and it is more widespread then the amount of wider sensitivity to sensory inputs is also increased, which is generally found in whiplash patients and also in sufferers from chronic nerve root pain in the neck. Both these conditions, cervical radiculopathy (where one of the exiting nerve roots from the spinal cord is compromised by for example compression) and whiplash may initiate complicated changes in the processing of pain information within the central nervous system. However, these changes in the central processing may be maintained by some pain inputs from the injured or altered disc, neck muscle, joint or ligament.

Jonathan Blood Smyth is the Superintendent of Physiotherapy at an NHS hospital in the South-West of the UK. He writes articles about back pain, neck pain, and injury management. If you are looking for physiotherapists in Bolton visit his website.