Definition
Whiplash is an injury resulting from a sudden extension or flexion of the neck. Whiplash can also be termed neck sprain or neck strain or, more technically, cervical acceleration/deceleration trauma. It is most often associated with being struck from behind in a car, although it also occurs during contact sports, falls, or other physical activities. Whiplash may also cause damage to vertebrae, ligaments, cervical muscles, or nerve roots.
Description
Whiplash occurs when the body is struck, usually from behind, and the head travels backwards to catch up with the body. The neck will flex until either the facet joints in the back of the vertebrae or the anterior longitudinal ligament in the front of the vertebrae stop the motion.
The muscles that are most often injured during an impact that causes whiplash are the sternocleidomastoids and the longus colli. The sternocleidomastoids are the large straplike muscles running down the front of the neck that pop out when the jaw is flexed. They are used to turn and support the head. The longus colli is a muscle that runs directly in front of the spine is used to turn the head from side to side and to bend the neck forward. The longus colli muscle aids the sternocleidomastoids in holding up the head and moving the neck. Often, the lognus colli muscle is weakened during whiplash and the sternocleidomastoid muscles become overworked as they compensate.
The facet joints in the anterior of the neck may also be damaged during a whiplash injury. There are two facet joints on the back of each vertebra. They are about a centimeter in size and guide the movement of the spine. When the neck bends backward during a whiplash impact, the joints can be compressed and then swell in response. This can cause pain, both in the neck and can also refer pain to other parts of the body. For example, if the facet joints between the second and third cervical vertebrae are compressed, pain may be felt in the back of the head.
A whiplash impact can also damage the anterior longitudinal ligament, which is a tough band of tissue that runs down the front of the vertebral column and holds the vertebral bones together. In automobile accidents, this ligament is often overstretched or torn. If it is torn, it can lead to vertebral disc herniation or to excessive movement of the spinal column. Such movement can result in pain spasms in the neck, cracking and grinding in the neck, or even numbness in the hands and feet.
Whiplash can also result in a herniated vertebral disc. The vertebral bones are cushioned between vertebral discs that are made up of an interior gel-like substance surrounded by a tougher outer layer. If this outer layer becomes damaged, the disc may rupture and the gel-like interior will be compressed out. The ruptured disc can put pressure on adjacent nerve roots and cause tingling, numbness or burning.
Damage to the central nervous system or the peripheral nervous system may occur during a whiplash injury. Most of the damage to the nervous systems involves compression injuries during which pressure is applied to nervous tissues, although damage can also be caused by stretching or torquing (twisting) of nervous tissues. In severe cases, compression injuries can affect the brain resulting in subdural or extradural hematomas (pooling of blood between the brain and the skull). Symptoms of this complication include anosmia (loss of smell), double vision, brief loss of consciousness, confusion and loss of motor skills.
Compression, stretching, and torque injuries to the spinal cord may also occur during trauma associated with whiplash. The most frequently occurring is root syndrome. Nerve roots exit the spinal cord on both sides of the body between vertebrae. When the spaces between vertebrae, also called foramen, become compressed, the nerve roots can be compressed or damaged. This can result in slight numbness, burning or tingling in any of the parts of the body that the nerve enervates. In more severe car accidents, whiplash can cause more critical damage to the spinal cord resulting in major neurological dysfunction or paralysis below the location of the injury. The important variables controlling the severity of the symptoms appear to be the force and the direction of the impact on the spine. As the area impacted by the trauma increases due to increased force, a greater portion of the cord is involved resulting in greater neurological dysfunction.
The peripheral nervous system can also suffer damage in a whiplash injury. These nerves can be compressed in the vertebral foramen and can also be stretched or compressed by other anatomical structures along their path. Only a very small compression or stretching is required to interrupt blood flow to a nerve cell. For example, blood flow to a nerve cell can be completely stopped if the nerve cell is stretched to 15% more than its original length. Such trauma to a nerve cell can result in numbness or tingling in the region affected by the nerve, but usually not pain. It is the irritation of the nerve following the trauma that causes pain in the peripheral nervous system.
Demographics
Anyone can suffer from whiplash, in particular people who drive in automobiles. Whiplash has been documented in people who are driving as slowly as five miles per hour. About 20% of people who are involved in rearend accidents in cars suffer symptoms of whiplash. In the United States, it is estimated that about 1.8 million people are subject to chronic pain and disability after an automobile accident, the majority of whom suffer from neck pain.
Causes and symptoms
Symptoms of whiplash include neck pain and stiffness, shoulder pain and stiffness, lower back pain, headaches in the back of the head, pain, and/or tingling in the hand or arm, dizziness, ringing in the ears and blurred vision. Often the pain associated with whiplash worsens several days following the injury. Some people suffer cognitive or psychological symptoms including difficulty concentrating, difficulty sleeping, memory loss, depression and irritability.
Symptoms of whiplash appear to follow one of two courses. In most people, symptoms will slowly abate within approximately three months. In a smaller proportion of people who experience whiplash, the symptoms become chronic and disability may result.
Diagnosis
Orthopedists (physicians specializing in the bones and joints) use a variety of diagnostic tools to evaluate the extent of injury following whiplash. This usually begins with a history of the accident and the symptoms experienced. A physical examination allows the physician to evaluate the range of motion in the neck, locations of pain in the neck, arms and legs, and function of nerves. An xray is almost always used to determine if any vertebrae have been damaged in the accident. However, because many of the injuries are to soft tissues, they are not well visualized using a standard x ray. The orthopedist may then recommend other diagnostic procedures that visualize these tissues more effectively. Magnetic resonance imaging (MRI) allows for visualization of the spinal cord and nerve roots that emerge between the vertebrae. A computed tomography study (CT) gives precise information about the bone and spinal canal using specialized xray technology. Another technology called a myelogram combines x rays with an injection of dye into the spinal canal and allows for detailed visualization of the spinal canal and nerve roots. An electromyogram (EMG) may also be used to determine the health of nerves and muscles using electrical impulses.
Treatment
Treatment for whiplash includes a variety of techniques and medications including exercises, pain-relieving medications, traction, massage, heat and ice, and ultrasound, depending on the symptoms. Although a physician should evaluate people who suffer whiplash, most of the time whiplash can be treated using home treatments and extensive medical care is not prescribed.
Both heat and cold are useful for treatment of symptoms of whiplash. Initial treatment for whiplash usually includes cold packs of ice applied to the neck for the first 24 hours. Heat may then be used to relieve pain throughout the neck and shoulders either using heating pads or hot showers. Physical therapists can apply deep heat treatments using ultrasound equipment.
Medications are useful for relieving acute pain associated with whiplash. Non-steroidal anti-inflammatory medications can be very helpful in relieving pain. Antidepressants may be prescribed because they inhibit the transfer of nervous signals along pain pathways.
A soft cervical collar may provide some relief for symptoms of whiplash; however, most physicians recommend that the use of the collar be limited to two to three weeks. Using the cervical collar for long periods may cause muscle strength to decrease and inhibit muscle flexibility.
Physicians have found that movement is important in preventing chronic symptoms of whiplash. Many doctors assert that simple exercises such as walking, muscle strengthening, and range of motion exercises help improve symptoms more quickly than remaining sedentary. In 2000, a study reported in the journal Spine demonstrated that patients who frequently performed a set of exercises immediately following an injury that caused whiplash recovered faster than patients who exercised less. The more active group performed a set of repetitive motion exercises 10 times an hour beginning within 96 hours of injury, while the less active group performed exercises a few times a day beginning two weeks after the injury. Of the more active group, nearly 40% reported that they had no symptoms of whiplash six months following the accident, compared with only 5% of the less active group.
Traction, under the supervision of an orthopedic professional, removes the pressure from the neck, and some people report relief from pain for several hours to several days following treatments. Physical therapy and/chiropractic adjustments are often prescribed to treat symptoms of whiplash. In rare cases, surgery is required to correct whiplash injuries.
Clinical trials
The National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) conducting a study in 2004 focused on preventing acute pain, such as that associated with whiplash, from becoming chronic pain. Research suggests that the emotional response to an injury to the neck, particularly fear of reinjury, contributes significantly to the development of chronic pain from whiplash. The study focused on two anxiety-reducing treatments as a way to prevent such chronic pain from developing. The principal investigator on the two-year study is Dennis C. Turk, Ph.D. (telephone number: 206-543-3387, or email: wads@u.washington.edu). Information is available on the institute's website at .
Resources
BOOKS
Foreman, Stephen M. and Arthur C. Croft. Whiplash Injuries: The Cervical Acceleration/Deceleration Syndrome. Second Edition. Philadelphia: Lippincott, Williams & Wilkins, 1995.
PERIODICALS
Cote, P., J. D. Cassidy, L. Carroll, et al. "A systematic review of the prognosis of acute whiplash and a new conceptual framework to synthesize the literature." Spine 26, no. 19 (2001): e445–e458.
Rosenfeld, M., R. Gunnarsson, and P. Borenstein. "Early Intervention in whiplash-associated disorders: A comparison of two treatment protocols." Spine 25, no. 14 (2000): 1882–1787.
OTHER
Centeno, Christopher J. "What is Whiplash?" Whiplash 101. (January 19, 2004). http://www.whiplash101.com/default1.htm.
Mayo Clinic Staff. "Neck Pain: Sometimes Serious." The Mayo Clinic. (February 07, 2002). http://www.mayoclinic.com/invoke.cfm?id=HQ01111.
"Neck Pain." American Academy of Orthopaedic Surgeons. 2000. (January 23, 2004). http://orthoinfo.aaos.org/brochure/thr_report.cfm?thread_id=11&topcategory=neck.
"Neck Sprain." The America Academy of Orthopaedic Surgeons. May 2000 (January 23, 2004). http://orthoinfo.aaos.org/fact/thr_report.cfm?thread_id=141&topcategory=neck.
"Whiplash." The America Academy of Orthopaedic Surgeons. October 2000 (January 23, 2004). http://orthoinfo.aaos.org/fact/thr_report.cfm?Thread_ID=232&topcategory=Neck.
"NINDS Whiplash Information Page." National Institute of Neurological Disorders and Stroke. July 1, 2001 (January 23, 2004). http://www.ninds.nih.gov/health_and_medical/disorders/whiplash.htm?format=printable.
ORGANIZATIONS
American Chronic Pain Association (ACPA). P.O. Box 850, Rocklin, CA 95677. (916) 632-0922 or (800) 533-3231; Fax: (916) 632-3208. ACPA@pacbell.net.
National Chronic Pain Outreach Association (NCPOA). P.O. Box 274, Millboro, VA 24460. (540) 862-9437; Fax: (540) 862-9485. ncpoa@cfw.com.
National Headache Foundation. 820 N. Orleans, Suite 217, Chicago, IL 60610. (773) 388-6399 or (888) NHF-5552; Fax: (773) 525-7357. info@headaches.org. http://www.headaches.org.
Juli M. Berwald, Ph.D.
