NECK, SHOULDER AND ARM PAIN ARISING FROM MEDIAN NERVE AFTER WHIPLASH INJURY

Abstract

Whiplash remains a challenging condition because the pathology is undefined. The purpose of this study was to evaluate the response of chronic neck, shoulder and arm pain to decompression of the median nerve at the wrist and pronator teres level.

In a prospective study of 150 cases following whiplash injury (108 carpal tunnel and 42 pronator teres syndrome) clinical symptoms were assessed by clinical, neurological, radiological and visual analogue scale. The pathophysiology of pain and effects of surgery have also been assessed by neuropeptide studies.

Clinical and neurological examination revealed signs and symptoms of carpal tunnel and pronator teres syndrome along with severe neck, shoulder and arm pain. Local anesthetic infiltration around the median nerve at the wrist and forearm abolished the chronic neck and shoulder pain within 10mins of injection. This demonstrated the site of pathology and temporarily relieved upper limb symptoms and trapezius muscle spasm as well. Neurophysiological studies were always normal.

Surgical intervention in successful cases cured chronic neck shoulder and arm pain with sensory and motor recovery. Also activities of daily life normalised permanently.

The main neurotransmitter peptides Substance P and Calcitonin gene related peptide levels returned to control levels six weeks after surgery in successful cases (p< 0. 005 and p< 0. 05 respectively). This is the biochemical evidence of effect of surgery in relieving pain and neuroinflammatory process.

Our study suggests that neck shoulder and arm pain following whiplash injury is caused by entrapment of the median nerve due to stretching. Surgical decompression of the carpal tunnel and pronator teres muscle yielded 93% and 80% good results respectively with the disappearance of chronic neck shoulder and arm pain. Consequently normalisation of daily activities were observed. Although mild hand symptoms caused by carpal tunnel syndrome have also been cured the primary aim of surgical intervention is to cure chronic neck shoulder and arm pain.