Residency · Residency · Orthopedic Surgery
Cervical Myelopathy and Radiculopathy
Introduction
Cervical spondylosis is the most common cause of spinal cord dysfunction in adults over 55 years. The degenerative cascade produces two distinct clinical syndromes: cervical radiculopathy (nerve root compression) and cervical myelopathy (spinal cord compression). Distinguishing between these entities and understanding their natural history guides treatment decisions ranging from conservative management to surgical decompression.
Pathophysiology
The degenerative cascade involves disc desiccation, loss of height, osteophyte formation, facet hypertrophy, ligamentum flavum buckling and hypertrophy, and uncovertebral joint spurring. Radiculopathy results from nerve root compression in the neural foramen by disc herniation, osteophytes, or foraminal stenosis, with C5-C6 and C6-C7 being the most commonly affected levels. Myelopathy results from spinal cord compression due to central stenosis, causing ischemia, demyelination, and neuronal loss, and may be insidious and progressive. Ossification of the posterior longitudinal ligament (OPLL) is a significant cause of myelopathy, particularly in East Asian populations. A congenitally narrow canal with a sagittal diameter less than 13 mm predisposes to myelopathy.
Cervical Radiculopathy
Clinical Presentation
Patients present with neck pain radiating into the arm in a dermatomal distribution, along with numbness, tingling, and weakness corresponding to the affected nerve root. | Root | Disc Level | Motor Weakness | Sensory Loss | Reflex |
| C5 | C4-C5 | Deltoid, biceps | Lateral arm | Biceps | |
|---|---|---|---|---|---|
| C6 | C5-C6 | Wrist extensors, biceps | Lateral forearm, thumb/index | Brachioradialis | |
| C7 | C6-C7 | Triceps, wrist flexors, finger extensors | Middle finger | Triceps | |
| C8 | C7-T1 | Finger flexors, hand intrinsics | Medial forearm, ring/small finger | None reliable | |
| T1 | T1-T2 | Hand intrinsics | Medial arm | None reliable |
The C5 root (C4-C5 disc) causes deltoid and biceps weakness, lateral arm sensory loss, and diminished biceps reflex. The C6 root (C5-C6 disc) causes wrist extensor and biceps weakness, lateral forearm and thumb/index sensory loss, and diminished brachioradialis reflex. The C7 root (C6-C7 disc) causes triceps, wrist flexor, and finger extensor weakness, middle finger sensory loss, and diminished triceps reflex. The C8 root (C7-T1 disc) causes finger flexor and hand intrinsic weakness with medial forearm and ring/small finger sensory loss. The T1 root (T1-T2 disc) causes hand intrinsic weakness with medial arm sensory loss.
Physical Examination
The Spurling test applies axial compression with extension and lateral bend toward the affected side to reproduce radicular symptoms and has high specificity at 93%. The shoulder abduction relief sign shows relief of symptoms with the arm placed on top of the head, reducing tension on the nerve root. Motor, sensory, and reflex testing are performed as outlined above. Peripheral nerve entrapment should be ruled out (double crush phenomenon).
Natural History
The prognosis is favorable, with 75 to 90% of patients improving with nonoperative management. Most acute soft disc herniations resorb over time.
Cervical Myelopathy
Clinical Presentation
Myelopathy presents with insidious onset of gait disturbance, hand clumsiness, and balance difficulty. Upper motor neuron signs include hyperreflexia, clonus, spasticity, and a Babinski sign (upgoing toes). Hand myelopathy signs include loss of fine motor skills, difficulty with buttons, and deteriorating handwriting. The Lhermitte sign produces an electric shock sensation down the spine with neck flexion. The gait is broad-based, spastic, and unsteady. Bowel and bladder dysfunction occurs in advanced cases.
Physical Examination
The Hoffman sign (flicking the middle finger DIP produces thumb and index finger flexion) suggests upper motor neuron disease. The inverted radial reflex (tapping the brachioradialis produces finger flexion instead of wrist extension) is another sign. Lower extremity hyperreflexia and ankle clonus are present. The grip-and-release test is abnormal when the patient cannot complete 20 repetitions in 10 seconds. Tandem gait assessment reveals difficulty walking heel-to-toe.
Severity Grading
The modified Japanese Orthopedic Association (mJOA) score ranges from 0 to 18. Mild myelopathy corresponds to a score of 15 to 17, moderate to 12 to 14, and severe to below 12.
Imaging
MRI is the gold standard for both radiculopathy and myelopathy, assessing disc herniation, cord compression, foraminal stenosis, and cord signal changes. T2 hyperintensity within the cord suggests myelomalacia or gliosis and is a poor prognostic sign. T1 hypointensity indicates chronic cord damage and a worse prognosis. CT myelography is an alternative when MRI is contraindicated and provides excellent bony detail. Radiographs assess alignment, disc space narrowing, osteophyte formation, and dynamic instability on flexion-extension views. Electrodiagnostic studies (EMG and NCS) help differentiate radiculopathy from peripheral neuropathy but are not useful for myelopathy.
Nonoperative Management (Primarily for Radiculopathy)
Nonoperative management includes NSAIDs, oral corticosteroids (short taper), and neuropathic pain agents (gabapentin, pregabalin). Physical therapy incorporates cervical traction, isometric strengthening, and postural training. Epidural steroid injections with a transforaminal approach can provide temporary relief and have diagnostic value. Activity modification and ergonomic adjustments are recommended, with serial clinical monitoring for any myelopathic signs.
Surgical Management
Indications
Myelopathy requires surgical decompression as the standard of care because it does not reliably improve with conservative management and typically progresses. Radiculopathy warrants surgery for progressive neurological deficit, intractable pain despite 6 to 12 weeks of conservative care, or significant motor weakness.
Anterior Approaches
ACDF (anterior cervical discectomy and fusion) is the workhorse procedure for 1 to 3 level disease, providing direct decompression of disc and osteophytes with high fusion rates exceeding 95% for single-level cases. Anterior cervical corpectomy is used for multilevel disease, OPLL, or vertebral body pathology, involving strut graft with plate fixation. Cervical disc arthroplasty is an alternative to ACDF for single-level disease that preserves motion but is contraindicated in myelopathy, instability, or significant facet arthropathy.
Posterior Approaches
Laminectomy with fusion using lateral mass or pedicle screw fixation is used for multilevel disease involving more than 3 levels when lordotic alignment is maintained. Laminoplasty expands the canal while preserving posterior elements and is ideal for multilevel myelopathy in lordotic spines; it avoids fusion but may cause axial neck pain and C5 palsy. Posterior approaches are preferred when pathology is primarily posterior (ligamentum flavum hypertrophy) or involves more than 3 levels.
Approach Selection
For 1 to 2 levels, the anterior approach is generally preferred. For 3 or more levels, a posterior or combined approach is used. Kyphotic alignment favors an anterior approach to restore lordosis, or a combined anterior-posterior approach. For OPLL, the anterior approach is used for focal disease and the posterior approach for extensive disease due to lower risk of dural tear.
Complications
C5 palsy presents as upper extremity weakness (deltoid) after decompression, occurring in 5 to 10% of cases and usually recovering within 6 months. Adjacent segment disease develops at a rate of 2.9% per year requiring reoperation. Dysphagia after an anterior approach is the most common complication but is usually transient. Other rare complications include recurrent laryngeal nerve injury, esophageal injury, and vertebral artery injury. Hardware failure, pseudarthrosis, and graft subsidence may also occur.
Clinical Pearls
Cervical myelopathy is a surgical disease, as conservative management does not reliably halt progression. The Spurling test is highly specific for radiculopathy, while the Hoffman sign and hyperreflexia suggest myelopathy. T2 cord signal changes on MRI indicate myelomalacia and portend a worse surgical prognosis. Most cervical radiculopathy resolves with nonoperative management, and surgery is reserved for refractory or progressive cases. Approach selection depends on the number of levels, alignment, and location of pathology.
References
- Fehlings MG, Tetreault LA, Riew KD, et al. "A Clinical Practice Guideline for the Management of Patients with Degenerative Cervical Myelopathy." Global Spine Journal. 2017;7(3 Suppl):70S-83S.
- Bono CM, Ghiselli G, Gilbert TJ, et al. "An Evidence-Based Clinical Guideline for the Diagnosis and Treatment of Cervical Radiculopathy from Degenerative Disorders." Spine Journal. 2011;11(1):64-72.
- Nouri A, Tetreault L, Singh A, et al. "Degenerative Cervical Myelopathy: Epidemiology, Genetics, and Pathogenesis." Spine. 2015;40(12):E675-E693.
- Luo J, Cao K, Huang S, et al. "Comparison of Anterior Approach Versus Posterior Approach for the Treatment of Multilevel Cervical Spondylotic Myelopathy." European Spine Journal. 2015;24(8):1621-1630.