Whiplash-associated disorders (WAD) is defined as “an acceleration-deceleration mechanism of energy transfer to the neck.” WAD may result from rear-end or side-impact motor vehicle collisions (MVCs), diving and other sports-related injuries, as well as from falls, assaults, and more. Because many bones and soft tissues may be involved in WAD, there are a variety of clinical signs and symptoms associated with the disorder.
In 1995, the Quebec task force coined the term WAD and broke it down into five divisions: WAD 0 includes no pain or exam findings; WAD I includes neck pain, stiffness, or tenderness as the only complaint with no exam signs; WAD II includes pain, stiffness, or tenderness with exam findings such as decreased range of neck motion and/or point tenderness of the neck; WAD III includes all of WAD II plus altered nerve function (sensory deficits and/or muscle weakness or altered deep tendon reflexes); and WAD IV includes fracture or dislocation with or without spinal cord injury.
WAD is usually seen in rear-end, low-impact collisions with about 90% of cases occurring at speeds of <14 mph. In a rear-end collision, the trunk of the body is initially forced back into the seatback followed by hyperextension of the neck and head, which then recoil forwards—all within about 600 msec, which is much faster than the 1,000 msec needed to voluntarily brace our muscles.
Studies support that the source of neck pain arises more often from injured joints than injured muscles. In about 60% of cases, neck pain is due to injury of the small facet joints, which are located on the sides of the neck, especially at levels C2-3 and C5-6. This can give rise to upper neck pain and/or headache (from C2-3), and/or lower neck pain radiating to the shoulder blades (C5-6) or worse, into the arms.
Fortunately, most acute WAD injured patients recover within three months. Unfortunately, about 40% do not improve and are then classified as having “chronic whiplash” (cWAD). Risk factors for WAD developing into cWAD include the following: 1) rapid and severe onset of neck pain and stiffness symptoms; 2) neurological deficit with arm pain (WAD III); 3) headaches; and 4) when urgent hospital admission is necessary. Older patients, those with pre-existing neck or low back pain, and individuals with slender necks have an elevated risk for a poor recovery. Depression, anxiety, and mood disorders are common in those with cWAD as well.