15.1 Cervical Spine Disorders, Radiculopathy, and Whiplash

Cervical Spine Disorders, Radiculopathy, and Whiplash

Functional Cervical Anatomy

The craniovertebral region includes the occiput, atlas and axis. The paired occipital condyles articulate with the superior surfaces of the atlas at C0–C1. This region contributes mainly to flexion and extension, as in a nod. Small motion in other planes and coupled motion can occur. One dynamic imaging study reported about 18° of mean flexion–extension at C0–C1, with substantial variability. A fixed percentage of a person's total cervical movement is unsuitable for clinical localization.

The C1–C2 complex has a median articulation around the dens and two lateral articulations. The transverse ligament of the atlas holds the dens against the anterior arch, and the alar ligaments help limit excessive motion. This level contributes a large portion of axial rotation. For example, one in vivo study reported about 38° of rotation at C1–C2 during a total rotation of about 72° to one side. These are group measurements, not an individual safety threshold.

The subaxial facets guide motion, with coupled movements that vary with level, posture and direction. The uncovertebral articulations form where the uncinate processes meet the adjacent superior vertebral bodies. Their position near the intervertebral foramina explains how degenerative enlargement can contribute to foraminal narrowing and affect an exiting nerve root.

Cervical Radiculopathy and Segmental Findings

Cervical radiculopathy involves dysfunction of a nerve root. Disc herniation or degenerative foraminal narrowing can contribute. Assess radiating symptoms, strength, sensation and reflexes, and compare sides. Root distributions overlap, and a typical map alone cannot determine the symptomatic level.

Cervical nerves C1 through C7 exit above the corresponding numbered vertebra. C8 exits between C7 and T1, and T1 exits between T1 and T2. Thus, a lateral C5–C6 disc or foraminal lesion commonly affects C6. The exact structural cause requires clinical correlation.

Look for concordance. Wrist extensor weakness plus a reduced brachioradialis reflex and altered thumb sensation supports C6 involvement more than thumb paresthesia alone. Compare possible peripheral entrapment, shoulder pathology and central signs before selecting treatment.

Wainner Cervical Radiculopathy Cluster

Perform provocative tests only when serious pathology and trauma precautions have been considered. Wainner and colleagues compared a four-item cluster with an electrodiagnostic reference. The items were:

1. Spurling A. In sitting, use side-bending toward the involved side and controlled axial compression. Record which symptoms are reproduced. Familiar radiating arm symptoms are more informative for radicular pain than isolated local neck discomfort.
2. Cervical distraction. Apply controlled distraction in supine and note whether symptoms diminish. The diagnostic response differs from prescribing a traction treatment dose.
3. Upper limb tension test A (ULTT1). The median-biased sequence uses scapular depression, shoulder abduction, forearm supination with wrist and finger extension, shoulder external rotation and elbow extension. Cervical side-bending can help differentiate the response. Compare familiar symptoms and side-to-side response rather than treating any sensation of stretch as positive.
4. Active ipsilateral rotation below 60°. Measure rotation toward the symptomatic side when safe.

In the original study, the positive likelihood ratio was 6.1 for three positive findings and 30.3 when all four were positive. The latter confidence interval was 1.7–538.2. A negative ULTT1 reduced probability in that study, but its estimated negative likelihood ratio of 0.12 also had a wide interval. Independent validation using a different reference approach supported the pattern of greater specificity with more positive findings. Estimates vary with setting and method.

A likelihood ratio multiplies pretest odds. For example, a 23% pretest probability gives odds of 0.23 ÷ 0.77. Multiplication by 30.3 gives odds of about 9.05, or about 90% post-test probability in this example. Use the cluster to update a working diagnosis, then interpret strength, sensation, reflexes and the course of symptoms.

Degenerative Cervical Myelopathy and the Cook Cluster

Degenerative cervical myelopathy (DCM) is a clinical syndrome of spinal cord dysfunction from degenerative compression. Disc and osteophyte changes and ligamentous changes can contribute. Ask about hand dexterity, bilateral limb symptoms, gait, falls and bladder or bowel change. Examine strength, sensation, gait and long-tract signs. Hyperreflexia, clonus or an extensor plantar response can coexist with reduced reflexes or weakness at an affected root level.

In Cook's derivation sample, defining a positive cluster as at least three findings yielded a positive likelihood ratio of 30.9, with a 95% confidence interval of 5.5–181.8. When the screening cutoff was at least one finding, a negative result meant zero findings and had a negative likelihood ratio of 0.18. These are study results with uncertainty. Do not count clonus as one of the five, use a low count to disregard a concerning presentation, or use the cluster as confirmation of the cause.

Progressive hand dysfunction and gait decline with long-tract signs call for prompt medical and spine assessment. MRI is used to investigate cord compression. With acute or rapidly worsening deficits, follow the emergency pathway. Withhold cervical thrust and traction when cord compromise is suspected and unresolved.

Canadian C-Spine Rule in Acute Trauma

The rule was developed in alert (GCS 15), stable patients aged 16 years or older with acute blunt trauma and concern for cervical spine injury. Check eligibility before using it. The original study excluded, among others, people with acute paralysis or known vertebral disease. Manage patients outside the eligible population using the relevant trauma pathway.

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1. High-risk factors. Age 65 years or older, extremity paresthesias, or a dangerous mechanism indicates imaging. Examples include a fall from at least 1 metre or five stairs, axial loading of the head, high-speed motor vehicle collision above 100 km/h, rollover or ejection, motorized recreational vehicle collision, and bicycle collision.
2. Low-risk factors. If no high-risk factor is present, at least one of these permits active motion assessment: simple rear-end motor vehicle collision, sitting in the emergency department, walking at any time after injury, delayed neck pain, or absence of midline cervical tenderness. A rear-end collision involving rollover, high-speed impact, being pushed into oncoming traffic or impact by a large truck or bus is not simple.
3. Active rotation. If permitted, ask for 45° of active rotation to each side without forcing the movement. If the patient cannot do it, imaging is indicated. If both directions meet the criterion, the rule does not indicate imaging.

The original rule addressed radiography. Under contemporary adult trauma pathways such as ACR and NICE, noncontrast CT is generally the initial cervical spine study when the rule indicates imaging. Follow the local pathway. A negative rule addresses clinically important cervical spine injury in the eligible setting. It does not screen for concussion or vascular injury. Acute unfamiliar head or neck pain with new focal or transient neurological symptoms calls for emergency assessment regardless of the spine rule.

Whiplash-Associated Disorders

Whiplash describes an acceleration–deceleration mechanism affecting the neck. Apply the Quebec Task Force grades after assessing serious injury and neurological status. The grades describe the presentation and do not establish a treatment protocol by themselves.

For uncomplicated injury after appropriate assessment, education, graded return to activity and suitable movement and exercise support recovery. Recheck symptoms and function. Neurological signs warrant appropriate medical evaluation and monitoring, with new or progressive signs changing the urgency. Suspected fracture or dislocation is managed through the trauma pathway before rehabilitation.

Craniocervical Flexion Test (CCFT)

The CCFT is a low-load test of controlled nodding and endurance. It assesses performance indirectly and can show substitution by more superficial muscles. Place a pressure sensor behind the upper neck with the patient supine and the neck supported in a neutral position. Set the baseline to 20 mmHg. Ask the patient to nod gently without pushing the head back, lifting it or breath-holding. Progress through 22, 24, 26, 28 and 30 mmHg, as control permits. Observe the motion and check for marked sternocleidomastoid or scalene substitution.

Record the highest controlled level maintained for 10 seconds as the pressure rise above baseline. For the performance index in the original approach, multiply this activation score by the number of successful 10-second holds at that level, up to 10. For example, at 24 mmHg, an activation score of 4 mmHg and six successful holds give an index of 24. If retraction or marked superficial substitution appears at 24 mmHg, do not award that level. Rest and check performance at the previous controlled level.

Worked Case: Neck Pain With Arm Symptoms

A patient with four weeks of right neck and arm pain reports tingling in the thumb. Right rotation is 38°. Spurling A and ULTT1 reproduce the familiar arm symptoms, which decrease during cervical distraction. Right wrist extension is mildly weak and the brachioradialis reflex is reduced compared with the left. The history and examination show no signs requiring emergency evaluation and the weakness is stable.

The four cluster findings increase the probability of cervical radiculopathy. The thumb, wrist extension and reflex findings support a working hypothesis of C6 involvement. Record strength, sensation, reflexes and task limitations at baseline. Choose education and tolerable active exercise, and consider an adjunct if it improves function or participation. Reassess the neurological findings and seek medical evaluation if weakness progresses or new bilateral, gait or other concerning findings appear.