Abstract
Cervical radiculopathy is a common disorder characterized by a radiating pain from the neck to the scapular area and the arm with associated symptoms including numbness, paresthesias, and weakness. Although it may be caused by injury, cervical radiculopathy is commonly associated with a normal aging process resulting in desiccation of the cervical discs, development of osteophytes, uncovertebral hypertrophy, disc herniation, and intervertebral foraminal narrowing and impinging on exiting nerve root. Cervical radiculopathy could be a self-limiting condition, but often requires supervised treatment by a spine specialist for optimal outcome. In the initial presentation, obtaining a careful history and combining this with a detailed examination is necessary to identify any red flags indicating myelopathy or progressive neurological deficits that require an expedited and more aggressive workup as well as treatment. In cervical radiculopathy without alarming sign, initial workup includes cervical x-ray followed by initial treatment comprising prescribed NSAIDs, prednisone taper, muscle relaxants, and a few weeks of physical therapy. In persistent cervical radiculopathy, advanced imaging followed by minimally invasive interventions may be necessary to control symptoms, restore function, and improve quality of life. Cervical MRI is the gold standard for diagnosing herniated disc or neuroforaminal impingement leading to cervical radiculopathy. Cervical epidural injection could drastically improve pain and help restore one’s function. Combining such interventions with rehabilitation, patient education, and ergonomic corrections often leads to satisfactory outcome. When 3 to 6 months of medically supervised conservative care fails to improve the patient’s cervical radiculopathy, surgical intervention may become necessary. Depending on etiology of nerve root impingement, cervical discectomy, and fusion, foraminotomy and cervical disc replacement are among surgical solutions.
Definition
Cervical radiculopathy is defined as dysfunction of a cervical nerve root resulting in painful neck, arm, and associated sensory, motor, and reflex abnormality. Involvement of the ventral root of the spinal nerve would result in motor weakness, and involvement of dorsal root of the spinal nerve would result in sensory deficits. Either root involvement may result in reflex abnormality. In most cases, both the ventral and dorsal roots are affected, resulting in cervical radiculopathy.
Cervical radicular pain is a radiating neck pain to the arm in a specific nerve root pattern, but it is not necessarily associated with loss of sensation, motor function, or reflex abnormality. One could experience radicular neck pain without abnormal physical exam findings of radiculopathy.
Cervical spine anatomy consists of seven cervical vertebrae (C1-C7) separated by five cervical discs (C2-C6). The C1 vertebra is ring shaped, does not have a central body, and its lateral masses articulate with the occipital condyle of the skull as well as the C2 vertebrae (C1-C2 joints). The C2 vertebral body is marked by the cephalad extension of the dens, tightly secured in place against the C1 arch by the transverse ligament, allowing for the majority of cervical spine rotation at the C1-C2 junction. There is no disc between C1 and C2 vertebrae. There are five intervertebral discs located anteriorly in between C2 and C6 vertebral bodies (C2-C3, C3-C4, C4-C5, C5-C6, C6-C7 discs). The C7 vertebra connects anteriorly with first thoracic vertebrae by means of C7-T1 disc. C2-C7 vertebrae articulate posterolaterally via facet joints that are situated in the coronal plane with inferior angulation, allowing for flexion, extension, and lateral bending of the neck. Uncinate process and its associated uncovertebral joint are features unique to C3-C7 spine. The uncovertebral joint is rudimentary at birth, evolves with age, stabilizes the cervical spine, and is prone to degenerative changes.
There are eight pairs of cervical nerve roots. Cervical spinal nerves are named corresponding to the vertebral body below the nerve, except C8. The C8 roots exit at the C7-T1 intervertebral foramen. Normally the foramina are largest in the upper cervical spine and gradually narrow distally, with the C7-T1 foramina being the most narrow. The intervertebral foramen is bordered posterolaterally by zygapophyseal joint, anteromedially by the uncovertebral joint, inferiorly and superiorly by the pedicles of the adjacent vertebrae, and anteriorly by the adjacent disc. Degenerative changes of the two joints and loss of disc height or herniation of the disc can result in narrowing of foramina and nerve root impingement.
Cervical spinal nerves exit through inferior portion of the cervical intervertebral foramina. C1-C3 spinal nerves have dorsal innervations including suboccipital (C1), greater occipital (C2), and third occipital nerve (C3). C1-C4 ventral primary rami would form the cervical plexus and C5-C8 ventral primary rami would contribute to brachial plexus innervating the arm.
C7 radiculopathy is the most common radiculopathy followed by C6, C8, and C5 in descending order of incidence. Most common reasons for cervical radiculopathy are posterolateral herniated disc, narrowing of the neuroforamina due to facet spondylosis, hypertrophied uncinate process with foraminal encroachment, and spondylolisthesis with or without instability affecting the adjacent neuroforamina. Less common causes include facet synovial cyst with encroachment of nerve root, extradural mass, spinal tumors, and abscess.
There are other medical conditions resembling cervical radiculopathy that should be carefully ruled out as part of medical evaluation of neck and arm pain. Orthopedic conditions like upper extremity tendinopathy, bursitis, as well as arthralgia could result in arm pain. Neurologic diagnoses such as peripheral nerve entrapment, demyelinating disease, intracranial events and neuromuscular conditions as well as peripheral neuropathy resemble cervical radiculopathy. Vascular conditions including thoracic outlet syndrome and vertebral artery dissection can also mimic cervical radicular symptoms.
Symptoms
Classic presentation of cervical radiculopathy is neck discomfort and associated unilateral arm pain in a specific nerve root pattern with sensory, motor, or reflex abnormality. Sensory complaints of numbness, tingling, burning, or electrical sensation follows a dermatomal pattern and weakness follows the same anatomic level myotome pattern. Of the subjective complaints, the distribution of hand paresthesias appears to have the greatest localizing value. There is level 1 evidence that suprascapular (C5-C6), interscapular (C7), and scapular (C8) pain suggests radiculopathy.
Common aggravating factors include motion of the head towards the painful side, free hanging of the arm, lifting heavier items, cough, sneeze, or valsalva. Often, pulling, pushing, and lifting items are not tolerated in the acute phase. Pain may improve when the head is tilted away from the painful side or if the affected arm is placed over the head. Clumsiness and deficits in fine motor movements (grip or pinch force) may precede gross weakness.
Clinicians should routinely inquire about symptoms of myelopathy. Myelopathy symptoms are often bilateral hand numbness, altered dexterity, poor balance, falls, and bowel or bladder dysfunction. These symptoms are not features of a discrete radiculopathy and should alert the clinician to rule out spinal cord compression.
Physical Examination
Full musculoskeletal and neurologic examination is indicated in evaluation of cervical radicular pain. Special attention is made to differentiate between objective findings compatible with radiculopathy and signs of myelopathy. If there is suspicion of other system involvement, physical examination needs to be expanded.
Visual Observation
Simple observation is a first step to proper diagnosis and treatment. Clinicians’ eyes should be trained to notice poor posture, abnormal body mechanics, spinal deformity, muscle atrophy, gait anomaly, use of assistive device, skin abnormalities, and nonverbal cues or behaviors.
Palpation
Ipsilateral tenderness and muscle tightness are common in patients with radiculopathy. The clinician should examine muscles for taut bands, especially in trapezius and periscapular muscles.
Gait Evaluation
It is important to evaluate the patient’s gait as part of the routine spine examination. Gait disturbance is not a normal finding of cervical radiculopathy due to degenerative foramina narrowing, but is a common complaint and finding in patients with cervical myelopathy. Gait disturbance on examination, warrants a more aggressive imaging work up with an MRI. Abnormal gait finding should prompt the clinician to educate the patient and family on fall precaution and use of assistive devices like a walker.
Range of Motion (ROM)
ROM of the cervical spine in all planes should be examined and deficits should be documented. Clinicians carefully reevaluate ROM of the C-spine to monitor progress in treatment. The normal cervical ROM is as follows: extension, 55 degrees; flexion, 45 degrees; lateral bending, 40 degrees; rotation, 70 degrees. Among activities of daily living (ADL), backing up a car requires the most combined ROM (rotation, extension, and side bend). Personal hygiene ADLs such as hand washing, shaving, and applying make-up necessitate a significantly greater ROM relative to mobility ADLs including walking and negotiating stairs.
Sensory Testing
Radiculopathy results in specific dermatomal abnormality in sensory examination of the shoulder girdle and the arms. Light touch, pinprick, and proprioception/vibration should be tested in the symptomatic and symptom-free arm. Based on the specific dermatomal deficits, the clinician can localize the anatomic level of nerve root impingement. There is a degree of overlap between dermatomal innervations of the arm. To date, the most standardized sensory testing guideline is published by International Standards for Neurological Classification of Spinal Cord Injury ( Fig. 5.1 ).
Deep Tendon Reflexes
Reflexes are tested bilaterally and compared. The response levels of deep tendon reflexes are grade 0-4+, with 2+ being normal ( Table 5.1 , Fig. 5.2 ). Clinicians should examine three reflexes as part of cervical spine examination: biceps brachii tendon (C5-C6, C5 primary), brachioradialis tendon (C5-C6, C6 primary), and triceps tendon (C7 primary). Hyporeflexia (diminished) or areflexia indicates involvement of lower motor neuron, including that specific nerve toot tested. Hyperreflexia (brisk) is an indication of central nervous system involvement.
| Root | Reflex | Key Muscle group (Neck and Arm) | Key Sensation point |
|---|---|---|---|
| C2 | Normal reflexes | Neck flexion | 1 cm lateral to occipital protuberance |
| C3 | Normal reflexes | Neck extension and lateral flexion | Supraclavicular fossa, mid-clavicle line |
| C4 | Normal reflexes | Shoulder elevation | Skin over acromioclavicular joint |
| C5 | Diminished biceps deep tendon reflex | Elbow flexor | Radial side of the antecubital fossa |
| C6 | Diminished brachioradialis deep tendon reflex | Wrist extension | Dorsal surface, proximal phalanx of the thumb |
| C7 | Diminished triceps deep tendon reflex | Elbow extension | Dorsal surface, proximal phalanx of the 3rd digit |
| C8 | Normal reflexes | Long finger flexors | Dorsal surface, proximal phalanx of the 5th digit |
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