Whiplash (medicine)

Whiplash is the common name for neck sprains, such as those caused by hyper extension/flexion injury to the cervical, thoracic or lumbar spines. The injury is referred to as "whiplash" due to the neck or back being thrown forwards and/or backwards at a rapid speed. This may cause the fibres of the neck muscles to tear, resulting in pain and often a decreased range of movement. Whiplash and whiplash-associated disorders (WAD) represent a range of injuries to the neck caused by or related to a sudden distortion of the neck.

Whiplash is commonly associated with motor vehicle accidents, usually when the vehicle has been hit in the rear, however the injury can be sustained in many other ways, including falls from bicycles or horses.

Cause
The exact injury mechanism that causes whiplash injuries is unknown. A whiplash injury may be the result of impulsive stretching of the spine, mainly the ligament: anterior longitudinal ligament which is stretched or tears, as the head snaps forward and then back again causing a whiplash injury.

Whiplash may be caused by any motion similar to a rear-end collision in a motor vehicle, such as may take place on a roller coaster or other rides at an amusement park, sports injuries such as skiing accidents, other modes of transportation such as airplane travel, or from being hit or shaken. Shaken baby syndrome can result in a whiplash injury.

Symptoms
Symptoms reported by sufferers include: pain and aching to the neck and back, referred pain to the shoulders, sensory disturbance (such as pins and needles) to the arms & legs and headaches. Symptoms can appear directly after the injury, but often are not felt until days afterwards. Whiplash is usually confined to the spinal cord (neck to pubic bone), and the most common areas of the spinal cord affected by whiplash are the neck, and the mid-back (middle of the spine).

Diagnosis
Reliably diagnosing a whiplash injury or disorder is not difficult for a trained doctor. If a patient cannot achieve the full motion, or has excessive range of motion,or chronic pain, the probable ultimate cause is the whiplash motion.Because whiplash may be caused by damage to the soft tissues of the spine (ex: tearing of a disk), these injuries often cannot be seen on an X-ray machine, and an alternative type of scanning machine such as an MRI is used instead. Certain severe injuries caused by whiplash movement, such as torn ligaments of the head-neck-joint system (e.g. the alar ligaments) cannot be displayed with non-functional imaging techniques. For showing ligamental damage functional imaging is essential.

Québec Task Force
The Québec Task Force (QTF) was a task force sponsored by the Société de l'assurance automobile du Québec, the public auto insurer in Quebec, Canada. The QTF submitted a report on whiplash-associated disorders in 1995, which made specific recommendations on prevention, diagnosis and treatment of WAD. These recommendations have become the base for Guideline on the Management of Claims Involving Whiplash-Associated, a guide to classifying WAD and guidelines on managing the disorder. The full report titled Redefining "Whiplash" was published in the April 15, 1995 issue of Spine. An update was published in January of 2001.

Québec Task Force grades of disorder
Four grades of Whiplash-Associated Disorder were defined by the Quebec Task Force on Whiplash-associated disorders (WADs):
 * Grade 1: complaints of neck pain, stiffness or tenderness only but no physical signs are noted by the examining physician.
 * Grade 2: neck complaints and the examining physician finds decreased range of motion and point tenderness in the neck.
 * Grade 3: decreased range of motion plus neurological signs such as decreased deep tendon reflexes, weakness, insomnia and sensory deficits.
 * Grade 4: neck complaints and fracture or dislocation, or injury to the spinal cord.

The QTF grading system is remarkably similar to the one developed by Dr. AC Croft in 1992 and subsequently published in 1993. However, the QTF Guidelines, published some 2 years later, fail to cite Dr. Croft's work. Croft AC: Treatment paradigm for cervical acceleration/deceleration injuries (whiplash). ACA J Chiro 30(1):41-45, 1993.

Consequences
The consequences of whiplash range from mild pain for a few days (which is the case for most people), to severe disability caused by restricted head movement or of the cervical spine, sometimes with persistent pain. The injury can exacerbate pre-existing conditions, such as spondylosis and other degenerative changes.

Whiplash protection
Protection efforts are hampered by lack of knowledge about the causes of whiplash injuries. The focus of preventive measures to date has been on the design of car seats, primarily through the introduction of headrestraints, often incorrectly called headrests. This approach is potentially problematic given the underlying assumption that purely mechanical factors cause whiplash injuries - an unproven theory. So far the injury reducing effects of head restraints appears to have been low, approximately 5-10%, because car seats have become stiffer in order to increase crash-worthiness of cars in high-speed rear-end collisions which in turn could increase the risk of whiplash injury in low-speed rear impact collisions. Improvements in the geometry of car seats through better design and energy absorption could offer additional benefits. Active devices move the body in a crash in order to shift the loads on the car seat.

Some car manufacturers have begun to implement various whiplash protection devices in their products in order to reduce the risk for and severity of injury, such as
 * Mercedes-Benz A-Class Active Head Restraint (AHR) ,
 * Saab (Responsible for the first active head restraint), Opel, Ford, Nissan, Subaru, and Peugeot - Active Head restraint (SAHR) ,
 * Volvo and Jaguar - Whiplash Protection System/Whiplash Prevention System (WHiPS), and
 * Toyota - Whiplash Injury Lessening (WIL).

Whether or not such devices offer a substantial benefit over vehicles without them remains controversial. In a test undertaken by the Swedish National Road Administration and an insurance company (Folksam), one test showed that a whiplash protection device was no guarantee against injury and that the degree of protection varies between vehicles both with and without whiplash protection devices. Yet The Journal of TRAUMA, Volume 51, No 5, November 2001 found that an Active Head Restraint helps reduce the risk of neck injuries by up to 75% in rear-end collisions.