3.1 Cervical spine disorders

Degenerative disorders of the cervical spine may present as any combination of neck pain, radiculopathy, or myelopathy. A careful history and physical examination is essential, as each diagnosis requires different treatment options and prognoses. This includes proper interpretation of patients’ complaints, a thorough physical examination, and an appropriate selection and review of diagnostic tests. In addition, various other aetiologies such as neoplastic, infectious, and inflammatory processes must be considered. This chapter will describe the history, physical examination, and treatment for degenerative disorders of the cervical spine.

A patient presenting with degenerative cervical disc disease typically presents with axial neck pain, radicular symptoms, myelopathic symptoms, or a combination of any of these. Patients with axial neck pain may present with pain referred to the shoulder, upper arm, or interscapular area (Figure 3.1.1) and, if so, these symptoms should not be confused with radicular symptoms associated with nerve root involvement. These patients may also complain of neck stiffness, muscle spasm, or headache. Upper cervical radiculopathy involving the C3 or C4 nerve root may be confused with axial neck pain, as the pain is typically in the neck and the trapezius muscle. Occipitocervical pain, particularly with neck rotation in elderly patients, may be a sign of degenerative atlanto-occipital or atlanto-axial joint pain.

In the setting of degenerative disease, radicular symptoms may be caused by a herniated disc, chronic disc degeneration with osteophyte formation, or instability within the spinal motion segment. While most patients will present with signs and symptoms consistent with involvement of a single nerve root, multiple roots are occasionally involved. Paresthesias generally develop in the early stages of compression. As the inflammatory process continues, radicular pain follows. Pain is typically exacerbated with Valsalva manoeuvres, neck extension, and when rotating the head toward the symptomatic side. Reproduction of pain with hyperextension and lateral rotation toward the symptomatic side is diagnostic and referred to as a positive Spurling’s sign (Figure 3.1.2). This decreases the size of the intervertebral foramen, further impinging the involved nerve root. This can also be accomplished with axial compression, but the latter is less reliable. An additional reliable indicator of cervical radiculopathy is the shoulder abduction relief sign, in which the ipsilateral shoulder is abducted, relieving the tension of the effected nerve root. A positive finding corresponds to the relief of the radicular symptoms. Similarly, axial traction of the neck may relieve radicular symptoms, also by increasing the dimension of the neural foramina.

Each cervical nerve root has its own characteristic pain distribution and motor deficits (Figures 3.1.3–3.1.7). Compression of C3 or C4 will manifest with pain about the posterior neck, occiput, and over the trapezius muscle and shoulder. Occasionally, C4 radiculopathy is referred down the anterior superior chest. C5 radiculopathy typically radiates down over the shoulder to the lateral aspect of the proximal arm. Patients will complain of fatigue or frank weakness in shoulder abduction and overhead activities, as the deltoid is almost purely innervated by the C5 nerve root (while the biceps has duel innervation form both C5 and C6). The biceps reflex primarily indicates C5 pathology. C6 radiculopathy involves neck pain radiating across the biceps, anterior arm, the radial aspect of the forearm, and the dorsum of the thumb and index finger. Weakness affects the biceps and/or wrist extensors. The extensor carpi radialis longus and brevis are innervated by C6, while the extensor carpi ulnaris is primarily innervated by C7. Therefore wrist extensor weakness may reflect either C6 or C7 pathology. The brachioradialis reflex is most directly affected by C6 compression. C7 radiculopathy is associated with pain along the posterior shoulder and arm, posterolateral forearm, and the middle finger. However, involvement of the index and ring fingers, as well as the first web space, can also be seen. The triceps muscle is most commonly affected, resulting in weakness and a diminished reflex. Unlike shoulder weakness, however, weakness of the triceps muscle is an infrequent complaint, unless the patient uses the muscle repetitively. Patients with C8 radiculopathy describe pain along the ulnar border of the arm and forearm to the small finger, often involving the ulnar half of the ring finger. Motor deficits may be noted with abduction, adduction, and flexion of the fingers. Intrinsic muscle atrophy of the hand is frequently seen in chronic cases.

The symptoms of cervical myelopathy may include gait difficulties, decreased manual dexterity, paresthesias, urinary urgency or frequency, spasticity, or weakness. In contrast to cervical or lumbar radiculopathy, pain is not a common presenting symptom. The gait disturbance is an early presenting complaint and the symptoms are usually insidious and slowly progressive. The characteristic stooped wide-based gait of the elderly is a common end result. Complaints involving clumsy or numb hands suggest upper extremity involvement, which may occur concurrently with, or follow, gait changes. Manual dexterity deficiencies will often silently progress until the patients are surprised at the lack of their ability to complete routine activities of daily living. Hand weakness may also be present, which typically manifests as decreased grip strength. Patients may have coexistent cervical and/or lumbar stenosis, in which case the clinical presentation may manifest as both upper and lower motor neuron lesions.

There are multiple physical examination findings consistent with cervical myelopathy. The finger escape sign is tested by asking the patient to hold all digits of the hand in an adducted and extended position. A positive finding is elicited when the two ulnar digits fall into flexion and abduction within 30s. In the grip and release test, the patient is asked to form a fist and then release all digits into extension, then to rapidly repeat the sequence. If the patient is unable to perform this motion 20 times within a 10-s period, the test is positive. To perform the Oppenheim test, a sharp object is run along the crest of the tibia. Extension of the great toe is a positive finding. The Babinski sign is a specific indicator of cord compression and is also positive when the great toe extends. It is elicited by running a sharp object distally along the lateral border of the plantar aspect of the foot and medially across the metatarsal heads. A Hoffmann reflex is strongly indicative of cervical cord impingement. It is present when the fingers and thumb flex in response to rapid extension of the distal interphalangeal joint of the long finger. Patients with spinal cord compression at C6 may exhibit the inverted radial reflex where, by tapping the distal brachioradialis tendon, a diminished reflex is elicited with a reciprocal contraction of the finger flexors (Figure 3.1.8). L’Hermitte’s sign refers to the perception of a generalized electric shock involving the upper and lower extremities as well as the truck with flexion of the neck (Figure 3.1.9). The scapulohumeral, or Shimizu, reflex is a very sensitive test which is elicited by tapping the tip of the spine of the scapula. The test is positive if there is brisk scapular elevation with abduction of the humerus. Finally, clonus may appear several weeks following cord compression. A positive test is defined as more than two repetitive beats during sudden wrist or ankle dorsiflexion.

Patients with symptomatology relating to their cervical spine are often initially sent for plain radiographic evaluation. However, degenerative changes are exceedingly common in the aging population and are very non-specific. Plain cervical radiography is therefore more useful in ruling out more threatening diagnoses such as neoplasm, or traumatic situations that might result in axial, coronal, or sagittal malalignment.

Magnetic resonance imaging (MRI) is the test of choice for patients with radiculopathy or myelopathy, as both the sensitivity and specificity are high. Readily demonstrated is cervical stenosis and secondary soft tissue abnormalities such as disc herniations, ligamentum flavum hypertrophy, facet hypertrophy, or other less common causes. It should be noted that there is MRI evidence of nerve root compression in as many as 19% of asymptomatic individuals, therefore radiographic abnormalities must be correlated with the patient’s history and physical exam findings. In patients with long-standing cervical myelopathy, MRI may also reveal intrinsic cord pathology such as atrophy or oedema. Limitations of MRI are difficulty in distinguishing soft tissue versus bone as in ossification of the posterior longitudinal ligament (OPLL) and less accurate assessment of bony foraminal stenosis.

Computed tomography (CT) is also a non-invasive study and is better at demonstrating bony abnormalities, as cortical margins are much more distinct than those seen with MRI. Therefore, stenosis secondary to osteophytes, hypertrophy of the uncovertebral joints, or hypertrophy of the zygoapophyseal joints are readily demonstrated with CT imaging. While axial images are helpful, 45-degree oblique reconstruction views will better assess the foramina and bony foraminal stenosis. CT myelography is an invasive study that precisely demonstrates the degree of spinal cord deformation and mechanical blocks to the flow of cerebrospinal fluid. A filling defect of myelographic dye on an oblique projection is a typical finding of nerve root compression (Figure 3.1.10). The combination of MRI and CT gives accurate imaging of bone and soft tissue landmarks and makes myelography rarely needed clinically.

The natural history of axial neck pain without neurological involvement is generally favourable and surgical intervention is not thought to result in better outcomes than conservative treatment measures. Non-operative treatment in patients with isolated neck pain is therefore recommended. The natural history of cervical radiculopathy was elucidated in a classic study published in 1963 by Lees and Turner. They conservatively followed 51 patients that initially presented with radicular pain. Of the ten patients with 10–19-year follow-up, three had only a single pain episode and no recurrence of symptoms, while three continued to have persistent mild symptoms. Only four were found to have more troublesome symptoms. No patients went on to develop myelopathic symptoms. These findings support the practice of initial conservative treatment in patients presenting with radiculopathy. The natural history of cervical myelopathy is highly variable. Some patients have a protracted course with only mild symptoms, while others go on to develop progressive disability.

As mentioned previously, patients with axial neck pain and/or radicular symptoms should be initially treated non-operatively. This should include non-narcotic analgesics, anti-inflammatories, a soft collar, and progressive exercises. Physical therapy modalities such as heat and ultrasound may make the patient more comfortable, although it is unclear if this has any significant advantage over the natural history. In the setting of neck pain without neurological involvement, cervical fusion procedures offer unpredictable results and should generally be avoided. Some surgeons favour the use of discography and fusion but controversy exists regarding the specificity of cervical discograms and fusion for axial neck pain.

If radiculopathy is present, the same non-operative treatment should be given for 2–3 months. A brief course of systemic corticosteroids may help alleviate symptoms and allow the natural history to take its course. Steroid injections, either in the epidural space or targeted toward isolated nerve roots, may also be effective both from a diagnostic and a therapeutic standpoint. Traction is often helpful, as it allows a compressed nerve some temporary relief and likely promotes recovery. Care should be taken to avoid traction that results in extension of the patient’s neck, which narrows the spinal canal and foramina, often resulting in increased symptoms. A cervical collar may be placed in the reverse position such that the narrow portion is anterior, leaving the neck in a slightly flexed position. In patients with radiculopathy, surgical intervention is indicated after several weeks of non-operative management (as outlined earlier) or if signs or symptoms worsen. The exception is the patient presenting with profound muscle weakness. These patients may need early intervention in order to maximize the chances of root recovery.

There is a minimal role for conservative treatment in patients with myelopathy. In patients with cervical stenosis and little or no significant myelopathy, conservative treatment or regular interval observation may be appropriate. As the natural history is that of slow stepwise deterioration, surgical intervention is generally required. Patients with mild to moderate symptoms can be expected to have a greater recovery of function, although some patients with severe symptoms can recover to a significant degree. It is important, however, that these patients understand that the surgical goal is to halt progression of their symptoms and that improvement is not predictable. If it is decided that both the cervical and lumbar spine require decompression, the cervical spine should be addressed first, followed by lumbar decompression at a later date.

Depending on a variety of factors, cervical disc disease can be approached either anteriorly or posteriorly. A patient with isolated radiculopathy (without significant neck pain) attributable to a lateral disc herniation or foraminal stenosis is typically treated posteriorly via a laminoforaminotomy (Figure 3.1.11). In this procedure, the medial 50% or greater of the ipsilateral facet joint is removed and the nerve root is decompressed under direct vision. Any anterior pathology that may be present need not be addressed as long as the extent of the nerve root is decompressed. Advantages of this approach are in the relatively low surgical morbidity and the fact that the motion segment is not destabilized (thus, a fusion procedure is avoided). Potential disadvantages include continued segmental degeneration, the possibility of incomplete decompression, and the inability to restore disc (and therefore foraminal) height. Anterior cervical discectomy and fusion (ACDF) is preferred in patients with radiculopathy or myelopathy associated with segmental kyphosis and significant neck pain. The spondylotic segment is distracted about 2mm, providing additional decompression of the foramen, which is then stabilized with bone graft (Figure 3.1.12). This approach typically directly addresses the compressive pathology on the cord or nerve root, restores disc (and foraminal) height, negates the possibility of repeat disc herniation, and minimizes the neck pain that might have been originating from the previously mobile segment. Disadvantages include the increased morbidity and operative time in harvesting autograft (allograft may also be used), decreased neck motion, complications related to plate utilization, possible non-union, and the possibility that a fused segment may accelerate adjacent segment degeneration. Cervical disc replacement is emerging as an additional treatment option for cervical radiculopathy. It offers many of the advantages associated with anterior neural decompression, while segmental motion is theoretically maintained. Early biomechanical and clinical studies are encouraging; however, long-term results are unknown.

Various surgical options are also available for patients presenting with isolated cervical myelopathy (without significant neck pain). These patients usually have cord compression from large osteophytes or OPLL, often extending posterior to the vertebral body. This situation necessitates partial or complete corpectomies followed by strut grafting. Alternatively, cervical spondylotic myelopathy can be treated posteriorly with multilevel laminectomy; however, postlaminectomy instability and kyphosis is a concern. Laminectomy and fusion is, therefore, another option. An additional posterior option is laminoplasty. While there are multiple specific techniques described, they all generally involve ‘opening’ the lamina of multiple levels in a trapdoor-type fashion, preserving the paraspinal musculature and facets. With this approach, motion is better maintained as compared to fusion procedures (but not entirely preserved) and the procedure is technically less demanding. A significant concern associated with laminoplasty procedures is the notion that it may result in increased postoperative neck pain in some patients. As a general rule, posterior approaches are preferred when decompression is required at more than three levels and when cervical lordosis is maintained. If there is two- to three-level involvement, an anterior approach is preferred. If a kyphotic deformity is present, an anterior approach is mandatory. If multilevel corpectomy and strut grafting is performed, a combined anterior and posterior approach should be considered to provide a biomechanically-sound posterior segmental fixation construct.

When evaluating patients with cervical degenerative conditions, it is essential to obtain a thorough history, provide a detailed physical examination, and obtain appropriate testing. With this information, the physician should be able to provide the vast majority of patients with a proper diagnosis and supply counselling on the natural history of the disease process. Most often, non-operative treatment is the preferred initial treatment and may be curative. Surgery is indicated only after an adequate trial of conservative management, or in patients presenting with cervical myelopathy. Various surgical approaches are available once surgery is decided upon, each approach having its own set of advantages and disadvantages. The ultimate decision should be based upon the patient’s diagnosis and symptoms, the site of the primary pathology, the number of segments involved, the patient’s sagittal alignment, and the surgeon’s preference. Regardless of the diagnosis or surgical approach, patients must be made fully aware of the potential limitations of a proposed intervention, in addition to the benefits. Only then will the probability of a successful procedure from the standpoint of both the physician and the patient be optimized.