Nerve Injury After Whiplash

Nerve injury after whiplash is a type of injury that has been documend in the medical literature.

Rear-end automobile collisions can cause very high accelerations of the human head, even during low speed crashes. During this rapid movement, the tissues of the neck can be strained or torn. Studies from the peer- reviewed medical literature have documented injuries to the muscles of the front and back of the neck, the ligaments of the spine, the vertebral and carotid arteries, and the many nerves that travel along the spine.

Two new studies have documented cases of nerve injuries after rear-end automobile collisions. In both of these reports, patients suffered injuries to the brachial plexus, the bundle of nerves and blood vessels that travel from the neck to the shoulder. Nerve injury after whiplash

The first study¹ details the case of a 30-year-old man who was riding a bus when it was struck from behind. He felt immediate pain on the left side of his neck, and went directly to the emergency room. X-ray imaging was normal, there were no neurological deficits, and he was sent home with some analgesics and instructions to see a physiotherapist.

After four months of physical therapy, the patient was referred to an orthopedic specialist for unremitting pain in his left shoulder and numbness and weakness in his left arm. The orthopedic physicians found a flattening of the cervical curve on x-ray (which is common after whiplash ligamentous injury) and nerve conduction studies showed a stretch injury to the brachial plexus.

“Clinical examination found revealed an altered shoulder profile, wasting over the upper trapezius region and left scapular musculature, severe winging of scapula upon press up position off the wall and possible development of impingement in his left shoulder.”

All of the nerves that innervate the shoulder and arm pass through the neck. This bundle of nerves, known as the brachial plexus, can be injured during a rear-end collision, when the front of the neck is rapidly stretched.

The patient was diagnosed with injury to the long thoracic nerve and spinal accessory nerve, both of which were injured during the violent extension of the head at the time of the crash.

The second study² reports on a 50-year-old woman who presented to the authors three years after a whiplash injury. The patient had progressive neck pain and stiffness, and “treatment with analgesics had proven unsatisfactory.”

The authors write that the patient had trouble lifting her shoulders, and the clinical examination showed atrophy of the muscles of the neck. EMG testing, as in the first study, found altered nerve functioning of the spinal accessory nerve. The patient was treated with botulinum toxin, “which considerably reduced her pain and spasm.”

These two studies show that the nerves of the human neck can be damaged in rear-end collisions, just as other studies have found. For patients who have shoulder pain, neurological symptoms, or muscle atrophy or spasm, it would be wise to look at the possibility of nerve injury. As the authors of one of these studies state, “Early diagnosis and treatment of these injuries may lead to more effective pain relief and a better functional outcome.” ¹

Omar N, Alvi F, Srinivasan MS. An unusual presentation of whiplash injury: long thoracic and spinal accessory nerve injury. European Spine Journal 2007;June 22, E-publication ahead of print.
Tan EK, Lo YL, Thomas J, Chan LL. Bilateral trapezius hypertrophy with dystonia and atrophy. Canadian Medical Association Journal 2007;176(12):1702-1703.