By Vladimir Djuric, M.D.

"Whiplash" is a term used to describe traumatic injury to the neck typically resulting from rear-impact motor vehicle accidents. It is one of the most common causes of chronic pain in developed countries with a prevalence of 1% in the general population. Typically, the prognosis after common whiplash is quite good. Three-quarters of those injured recover completely within six months. Unfortunately, for the remaining 25% persistent neck pain, headaches, shoulder pain, and a variety of other symptoms can become a permanent fixture in their lives. In 10% the symptoms are severe; 4% are unable to return to their previous occupation.

Until recently our understanding of the pathophysiology of whiplash has been very limited. Thanks to several key researchers this has changed immensely over the past decade. Bogduk and his colleagues in Australia have conducted excellent studies identifying cervical facet joints as a primary cause of ongoing pain. Small tears in the intervertebral disc wall have also been implicated as residual "pain generators". The usual diagnostic tests (X-ray, CT, MRI, and EMG) are typically normal, giving little insight into what is responsible for the ongoing pain. This can prove to be quite frustrating for both the patient and his physicians who are searching for a diagnosis. Only provocative spine injection procedures done under fluoroscopy (X-ray) can reliably and objectively identify the exact source of pain.

Even so, once identified the treatment options remain quite limited. Medications such as non-steroidals, narcotics, and muscle relaxants only treat the symptoms; most of the time inadequately. Physical therapy and chiropractic may provide a considerable degree of symptom relief, but many times these benefits are temporary, prompting frequent return visits. Even the latest treatment, radiofrequency thermal ablation, a procedure which destroys the nerves supplying the painful structure, works for only about a year before the nerves grow back and the procedure needs to be repeated.

A relatively unknown yet very effective treatment for cervical spinal pain is prolotherapy. Also known as non-surgical ligament reconstruction, prolotherapy works by addressing the cause of the pain: ligament and tendon relaxation and joint instability. The usual early diagnosis, cervical sprain/strain, although non-specific, is appropriate in that it implicates soft tissue as the injured structure. More specifically, it is the connective tissue, rich in pain sensitive nerve endings, which sustains the brunt of the injury. Structures including ligament, tendon, joint capsule and the intervertebral disc wall are all made of this connective tissue. In cases where the stretch capacity of the connective tissue has been exceeded, laxity and incompetence may result, rendering the intervertebral segment unstable. The excess motion leads to irritation of the nerve endings and thus pain.

What may start as a very localized problem can spread to adjacent areas and even the contralateral side. This "regionalization" of symptoms is due to compensatory postural and movement abnormalities; unsuccessful adaptations made by the body in an effort to minimize pain (similar to a limp due to a painful hip or knee). Sleep disturbances, difficulty with concentration, depression, and anxiety are other complications of whiplash. Buskila and colleagues found that over 20% of individuals sustaining neck injuries went on to develop symptoms consistent with fibromyalgia, making whiplash one of the most common traumatic causes of this condition.

Based on the history, pain diagram, and physical examination findings, a specific cervical segment can usually be identified as the probable cause of pain. Individuals with segmental hypermobility or recurrent somatic dysfunction of the upper cervical segments (C2-3 and above) usually complain of pain at the base of the skull and headaches. Middle cervical dysfunction tends to produce primary neck discomfort. Lower cervical involvement (C5-6 is the most commonly injured segment) leads to lower neck and posterior shoulder pain. These symptoms are commonly attributed to myofascial pain syndrome, suggesting muscular etiology even though the symptoms are directly related to spinal dysfunction.

Prolotherapy involves the injection of a proliferant solution, usually 15% dextrose mixed with anesthetic, into the damaged connective tissue. Once injected, the proliferant elicits an inflammatory response. The first step in the natural healing cascade is thus initiated. After an initial "clean-up" by various white blood cells, fibroblasts migrate to the area to begin the repair process. These cells produce collagen which repairs and reinforces the damaged connective tissue. As it matures, the collagen shrinks, slowly tightening the hypermobile segment. As with any painful condition, early diagnosis and intervention is extremely important. As chronicity progresses, pain centralization and multifocal involvement make treatment much more difficult and time consuming. Even so, even the most complicated whiplash sufferers stand to benefit, at least to some degree, from prolotherapy.

The treatment involves a series of injections spaced 2-4 weeks apart. In the neck, the spinous ligaments, facet joint capsules and muscular attachments of the trapezius, levator scapulae and suboccipital muscles are usually addressed. Surprisingly, the multiple injections are very well tolerated by the patient, although some are premedicated prior to the treatment in order to ease some of the discomfort.

Significant improvement, defined as a 50% drop in pain score, should be realized by the fourth treatment. Patients with localized symptoms and cervicogenic (tension) headaches, usually have the earliest and most impressive results.

Prolotherapy is not a first line treatment for whiplash. However, in cases where most other interventions have failed, it is surprisingly effective. Because new collagen tissue is created and the weakened segment is strengthened, the treatment is in many instances permanent. For many patients it is the only treatment likely to provide lasting benefit and improve quality of life.