Cervical Spondylotic Myelopathy: Signs and Symptoms are Protean

•Pain in the neck, subscapular area, or shoulder.

•Numbness or paresthesias in the upper extremities. These are usually nonspecific, although dermatomal specific sensory complaints can occur from a coexisting radiculopathy.

•Sensory changes in the lower extremities. These are common and typically involve the dorsal columns.

•Motor weakness in the upper or lower extremities.

•Gait difficulties. Many patients with cervical spondylotic myelopathy have a "spastic gait" that is broad-based, hesitant, and jerky, (1) compared with the smooth rhythmic normal gait.

•Myelopathic or "upper motor neuron" findings (ie, spasticity, hyperreflexia, clonus, Babinski and Hoffman signs, and bowel and bladder dysfunction). These often occur within a confusing framework of:

•"Lower motor neuron" findings (eg, upper extremity hyporeflexia and atrophy). The upper motor neuron signs predominate typically below the level of the clinically expressed lesion.

Gorter (9) reviewed 1,076 cases of cervical spondylotic myelopathy and concluded that a subtle gait disturbance is the most common presentation. Spastic gait occurred first, followed temporally by upper extremity numbness and loss of fine motor control of the hands. Lundsford et al (10) confirmed this presentation pattern in their series as well.

Numbness, decreased vibratory sense, and decreased fine motor control in the hands are common in patients with cervical spondylotic myelopathy. Epstein et al (11) found that 55% of their patients with cervical spondylotic myelopathy over age 65 had such symptoms. No specific spinal level accounts for this hand involvement, although it is believed to be associated with dysfunction above the C6-C7 level. (1)

Bowel and bladder dysfunction is also common. In a series of 269 patients, (12) bowel dysfunction was observed in 15% and bladder dysfunction was observed in 18%. Epstein et al (11) found that 20% of their patients with cervical spondylotic myelopathy over age 65 had bladder dysfunction, mostly associated with urinary retention. Likewise, Lundsford et al (10) found that 50% of their patients had bowel or bladder dysfunction or both.

Diagnosis
Keep three facts in mind when contemplating the diagnosis of cervical spondylotic myelopathy (13- 17):

• It can cause a vast array of signs and symptoms
• There are no pathognomonic findings
• The onset is insidious, with long periods of fixed disability and episodic worsening.

Differential diagnosis is broad
The differential diagnosis of cervical spondylotic myelopathy is quite broad. It is important to exclude both multiple sclerosis (a central demyelinating process with a tendency to cause both motor and sensory abnormalities) and amyotrophic lateral sclerosis (which affects both upper and lower motor neurons), as their clinical presentations are similar to that of cervical spondylotic myelopathy. Cervical spondylotic myelopathy does not affect the cranial nerves or the normal jaw jerk reflex, whereas these other disorders may. In addition, amyotrophic lateral sclerosis is a pure motor disease; therefore, sensation is not affected. (2) Cervical spondylotic myelopathy may have motor findings similar to those of amyotrophic lateral sclerosis, in addition to sensory findings such as numbness or paresthesias in the upper extremities. Other disorders in the differential diagnosis include spinal cord tumors, syringomyelia, subacute combined degeneration, cerebral hemisphere disease, and peripheral neuropathy. Normal pressure hydrocephalus, with its gait and bladder involvement, should also be considered.

Radiographic studies: MRI most valuable
The diagnostic workup of cervical spondylotic myelopathy often includes cervical radiographs, which may demonstrate osteophyte formation, kyphosis, or subluxation. The most valuable tool, however, is MRI. Along with the ability to rule out a tumor or syrinx (a slit-like cavity in the spinal cord), MRI allows for specific evaluation of the spinal cord, intervertebral discs, vertebral osteophytes, and ligaments. (4) Signal changes on T2-weighted MRI images at the level of spinal compression are often increased in patients with cervical spondylotic myelopathy. Such findings are thought to represent edema, inflammation, ischemia, myelomalacia, or gliosis. Several studies assessed preoperative and postoperative MRIs in patients with cervical spondylotic myelopathy and correlated the degree of T2-weighted signal changes with subsequent postoperative improvement.(18-20)

Cleveland Clinic Journal of Medicine
Volume 70, Number 10, October 2003