Cervical Spondylotic Myelopathy
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Direct answer
Cervical spondylotic myelopathy is compression of the cervical cord by degenerative disc, facet and ligamentous changes within a narrowed canal, most often at the mid-cervical levels. Its signs are upper motor neurone, including a positive Hoffmann sign, hand clumsiness and a broad-based gait. Surgery is considered for moderate or progressive disease, with anterior or posterior decompression chosen by the number of levels and the pattern of canal narrowing.
What you must remember
- Hoffmann sign: flicking the distal phalanx of the middle finger causes flexion of the thumb and index finger, and a positive result indicates an upper motor neurone lesion in the cord.
- Hand clumsiness: difficulty with buttons, writing and fine grip, from loss of fine motor control, is a common early complaint.
- Gait and reflexes: a broad-based, spastic gait with hyperreflexia, an extensor plantar response and sometimes Lhermitte sign on neck flexion.
- Nurick grading: grade 0 has root symptoms without cord signs, grade I cord signs with normal gait, grade II gait disturbance not preventing employment, grade III gait disturbance preventing employment, grade IV walking only with assistance, and grade V wheelchair bound or bedridden.
- MRI: shows the levels of compression, the cord signal change and the anterior or posterior pattern of narrowing, while CT myelography helps when MRI is contraindicated.
- Surgical choice: anterior decompression suits focal disease, while multilevel disease or ossified posterior longitudinal ligament is usually approached posteriorly.
- Prognosis: early decompression before permanent cord damage gives the best recovery, and marked cord signal change predicts a poorer outcome.
Deciding how to decompress the cord
A 58-year-old retired accountant has clumsy hands, a broad-based gait and MRI evidence of multilevel canal narrowing from C4 to C6. The decision follows severity, the number of levels and the pattern of compression.
- Confirm cord involvement: upper motor neurone signs such as hyperreflexia, a positive Hoffmann sign and a broad-based gait confirm myelopathy rather than radiculopathy alone.
- Grade the severity: Nurick grading and the Japanese Orthopaedic Association score record the baseline and guide the timing of surgery.
- Map the compression: MRI shows the levels, the cord signal change and whether compression is anterior, posterior or both.
- Count the levels: focal anterior compression at one or two levels suits anterior decompression and fusion.
- Choose posterior surgery for multilevel disease: multilevel narrowing, especially with ossified posterior longitudinal ligament, is treated by laminoplasty or laminectomy, depending on stability.
- Counsel on complications: C5 nerve root palsy after posterior decompression and adjacent segment disease after anterior fusion are discussed before consent.
Where the exam tries to catch you
Myelopathy questions test recognition of upper motor neurone signs and the choice of surgical approach.
- Trap: attributing bilateral hand clumsiness and a broad-based gait to peripheral neuropathy Correct: clumsiness with upper motor neurone signs points to cord compression, so the cervical spine must be imaged.
- Trap: choosing anterior fusion for diffuse multilevel canal narrowing Correct: multilevel disease, especially with ossified posterior longitudinal ligament, favours posterior decompression, since anterior surgery across many levels is impractical.
- Trap: operating on mild myelopathy with a normal gait Correct: mild disease can be observed, and surgery is discussed for moderate or progressive myelopathy.
Frequently asked questions
What is the Hoffmann sign in cervical spondylotic myelopathy?
The Hoffmann sign is elicited by flicking the distal phalanx of the middle finger, causing flexion of the thumb and index finger. A positive Hoffmann sign in cervical spondylotic myelopathy indicates an upper motor neurone lesion in the cord.
What is Nurick grading in cervical spondylotic myelopathy?
Nurick grading classifies cervical spondylotic myelopathy from grade 0, with root symptoms only, to grade V, which is wheelchair bound or bedridden. Grade III means a gait disturbance that prevents employment, and grade IV means walking only with assistance.
When is anterior decompression preferred over posterior decompression for cervical myelopathy?
Anterior decompression is preferred for cervical spondylotic myelopathy with focal compression at one or two levels, where anterior pathology dominates. Multilevel disease, or ossified posterior longitudinal ligament, is more often approached posteriorly.
What complication follows posterior decompression for cervical myelopathy?
C5 nerve root palsy is a recognised complication after posterior decompression for cervical spondylotic myelopathy, causing deltoid and shoulder weakness. It usually recovers over weeks to months, and patients are counselled about it before surgery.