Definition

Cervical sprain or strain typically refers to acute pain arising from injured soft tissues of the neck, including muscles, tendons, and ligaments. The most common event leading to such injuries is motor vehicle collision. The mechanism of injury is complex. During a rear-end motor vehicle collision, the initial head and neck acceleration lags behind vehicular acceleration. Eventually, head and neck acceleration reaches up to 21⁄2 times the maximum car acceleration, which subsequently results in dramatic deceleration at end range of motion of the neck [1,2]. Whereas such injury can also result in fracture, disc, or neurologic injury, cervical strain or sprain, by definition, excludes these entities.

Although these other entities need to be excluded from the differential diagnosis, recent evidence implicates the zygapophyseal joints as a source of neck pain after whiplash injury. Specifically, in a randomized controlled trial in which the medial branches of the cervical dorsal rami were blocked with local anesthetic or treated with saline, it was shown that 60% of patients with whiplash injury had complete neck pain relief after injection of local anesthetic compared with no relief by injection of placebo [3].

Many factors have been associated with worse outcome in acceleration-deceleration injuries involving motor vehicles. Older women tend to have a worse prognosis than that of younger women and men in general. In addition, poor education and a history of prior neck pain are prognostic factors for worse pain in women. Low family income, history of prior neck pain, and lack of awareness of head position in the crash are associated with a poor prognosis in men [4]. Additional crash-related factors associated with a worse outcome include occupancy in a truck, being a passenger, colliding with a moving object, and getting hit head-on or perpendicularly [5]. A high intensity of neck pain, a decreased onset of latency of the initial pain, and radicular symptoms are also prognostic of worse outcomes [6]. Because many of these injuries result in initiation of litigation by patients, this too is a poor prognostic indicator.

Other causes include sleeping in awkward positions, lifting or pulling heavy objects, and repetitive motions involving the head and neck.

Estimates exist that 1 million whiplash injuries each year are due to motor vehicle collisions. The annual incidence varies worldwide, but in North America and western Europe, the incidence is likely to be at least 300 per 100,000 inhabitants [6].

Symptoms

The most common presentation of patients with cervical strain or sprain is nonradiating neck pain (Fig. 6.1). Patients will also complain of neck stiffness, fatigue, and worsening of symptoms with cervical range of motion. The pain often extends into the trapezius region or interscapular region. Headache, probably the most common associated symptom, originates in the occiput region and radiates frontally. Increased irritability and sleep disturbances are common. Paresthesias, radiating arm pain, dysphagia, visual symptoms, auditory symptoms, and dizziness may be reported [7,8]. Whereas an isolated cervical sprain or strain injury should be without these symptoms, there is the possibility of concomitant neurologic or bone injury. If these symptoms are present, alternative diagnoses should be suspected. Myelopathic symptoms, such as bowel and bladder dysfunction, which suggest a different diagnosis that is more serious, must be investigated.

Physical Examination

The primary finding in a cervical sprain or strain injury is decreased or painful cervical range of motion. This may be accompanied by tenderness of the cervical paraspinal, trapezius, occiput, or anterior cervical (i.e., sternocleidomastoid) muscles (Fig. 6.2).

A thorough neurologic examination should be performed to rule out myelopathic or radicular processes. In an isolated cervical sprain injury, the neurologic examination findings should be normal.

The result of the neurocompression test, in which the patient is asked to rotate and extend the head, thereby reducing the neuroforaminal space, should be negative with cases of cervical sprain or strain.

Functional Limitations

Restricted range of motion of the cervical spine may contribute to difficulty with daily activities, such as driving. Patients often complain of neck fatigue, heaviness, and pain with static cervical positions, such as reading and working at the computer. Sleep may be affected as well.