The term “whiplash syndrome” is used to describe an injury to one or more elements of the neck region, which can occur when inertial forces are applied to the head.
This name is usually reserved when no signs of cervical spine injury are seen on radiological examinations and in the absence of signs of nerve root injury. It is a diagnosis of exclusion that must be made once other more severe injuries have been ruled out.
Whiplash syndrome (CRS) is a frequent injury, although its prevalence has never been determined in a reference population and its incidence has not been assessed prospectively.
In the US, it has been calculated that between 20 and 52% of those injured in a motor vehicle accident (MVA) may suffer an SLC, inferring that the annual incidence would be around 3.8/1,000 inhabitants, variable according to the different countries.
Despite its bad reputation, CRS is a mild injury, and in most patients, it recovers in 2-3 months without problems. After this period, the rate of recovery decreases, and the symptoms stabilize after 2 years.
Simplistically viewed, the outcome for an individualized patient can follow two paths: the pain will resolve within the first few months, or it will persist indefinitely. What is not clear is the proportion of patients who will not recover.
Despite the great variability between the different authors, studies would indicate that between 14 and 42% of patients with CRS would develop chronic pain in the neck region, and approximately 10% would have constant and significant pain on an ongoing basis. indefinite.
Etiopathogenesis
At the moment of impact, the vehicle is seen to be accelerated forward followed about 100 m later by a similar acceleration of the trunk and shoulders of the injured person from the car seat.
The head, on which no force acts, remains static in space, the result of which is a forced extension of the neck, while the shoulders move forward.
After extension, the inertia of the head is overcome and forward acceleration occurs. At this time, the neck acts as a lever with the increased forward acceleration of the head, forcing the neck to flex.
However, the forces involved are considerable: in an impact at a speed of 32 km/h, the head reaches a maximum acceleration of 12 g during extension.
All studies of rear impact accelerations in a car assume that the force is transmitted directly. The victim’s head is in an anatomical position facing forward, which is not applicable to the reality of most AVMs.
Thus, if the head is in a slight rotation, the impact would further force this rotation before extension occurred. This fact has significant consequences since the rotation of the cervical spine places most of the structures (apophyseal joints, intervertebral disc and ligaments) in a situation that is more susceptible to injury.
Since CRS that progresses to chronicity does not have a fatal outcome, there are no pathological studies available to determine the location or nature of the lesions.
However, we do have studies on experimental animals, carcasses, clinical observations, and studies using radiography, computed tomography (CT), and magnetic resonance imaging (MRI) techniques.
Despite its limitations, and combining the evidence obtained from clinical and animal studies, possible injuries can be inferred in the interapophyseal joints (rupture of the joint capsule, blood effusion, fissures, articular cartilage injuries), intervertebral discs ( disinsertion, fissuring, and rupture of the annulus), muscles (partial or total tears with bruises), ligaments (incision of the anterior joint vertebral ligament.
The interspinous, the posterior common vertebral and the yellow), atlas-axis region (odontoid fracture, among others, ligamentous injuries), vertebrae cervical (unnoticed fractures), brain (bruises and hemorrhages), other structures (temporomandibular joint, cervical sympathetic nerve, avulsion of the occipital due to avulsion of the nuchal ligament, paralysis of the vocal cords.
