Spondylosis describes the degenerative changes within vertebrae and intervertebral discs that occur during ageing or secondarily to trauma or rheumatoid disease. The changes are common in the lower cervical and lower lumbar region.
Several, often related, factors are important in producing signs and symptoms, including:
• Osteophytes-local overgrowth of bone
• Congenital narrowing of the spinal canal
• Disc degeneration with posterior or lateral disc protrusion
• Ischaemic changes in the cord and nerve roots The commoner clinical syndromes will be described. In all these syndromes MRI is now the investigation of choice, if available, replacing myelography. Lateral cervical disc protrusion (Fig. 18.22) The patient complains of pain in the upper limb. A C7 protrusion is the commonest lesion. There is root pain (see p. 898), which radiates into the affected myotome(scapula, triceps and forearm extensors in a C7 lesion) and a sensory disturbance (tingling, numbness) in the affected dermatome. There is weakness and, later, wasting of muscles innervated by the affected root (triceps and finger extensors in a C7 lesion) and reflexes using this root will be lost (the triceps jerk in a C7 lesion). Although the initial pain is often severe, most cases recover with rest and analgesics. It is usual to immobilize the neck in a collar. Plain X-rays of the cervical spine(oblique views) show encroachment into the exit foraminae by osteophytes. In cases where recovery is delayed,
Central cervical disc protrusion (cervical myelopathy) Posterior disc protrusion (see Fig. 18.22), which is common at C4/S, CS/6 and C6/7 levels, causes spinal cord compression (see p. 898). Congenital narrowing of the canal, osteophytic bars and ischaemia are contributory
factors. The patient complains of difficulty in walking. Frequentlythere are no symptoms in the neck. A spastic paraparesis (or tetraparesis) is found, with variable sensory loss. A reflex level in the upper limbs and evidence of lateral disc protrusion may coexist.Plain films may show narrowing of the sagittal diameter of the spinal canal and osteophytes but the changes correlate poorly with signs and symptoms. MRI or myelography is necessary to demonstrate the level and extentof cord compression. Cervical laminectomy or anterior fusion of the vertebral bodies with removal of the disc may be necessary when the ord compression is severe or progressive. The results of surgery are often disappointing. Recovery of the ‘pyramidal’ signs is unusual, although progression may be halted.
A collar should be fitted. Manipulation of the neck should be avoided.
Thoracic disc protrusion Central protrusion of a thoracic disc is a rare cause of paraparesis.
Lateral lumbar disc protrusion
The LS and S1 roots are commonly compressed by lateral prolapse of the L4/S and LS/S1 discs, respectively. There is low back pain and ‘sciatica’ (pain radiating down the buttock and lower limb). The onset may be acute and follow lifting a heavy weight, or may be subacute and
apparently unrelated to exercise. Straight leg raising is limited. There may be loss of reflexes (ankle jerk in an S1 root lesion or knee jerk in
an L4/S lesion) and weakness of plantar flexion (S1) or extension of the great toe (LS). Sensory loss may be found in the affected dermatome.
Plain films of the lumbar spine show narrowing of the disc space, osteophytes or a narrow canal. Unsuspected malignancy or infection may be demonstrated. Most cases resolve with rest and analgesics. In the minority, MRI or myelography is necessary and laminectomy is indicated when a root lesion is shown. Central lumbar disc protrusion (cauda equina syndrome)
A central disc protrusion causes a lesion of the cauda equina with back pain, weakness of the lower limbs, sacral numbness, retention of urine, impotence and areflexia. Many nerve roots are involved.
The onset is either acute (a cause of an acute flaccid paraparesis) or chronic, when intermittent claudication occurs.
Neoplasms in the lumbosacral region cause a similar picture.
The condition should be suspected if a patient with back pain develops retention of urine. Urgent MRI or myelography followed by decompression is indicated. Spinal stenosis
Narrowing of the lumbar spinal canal produces back painand is an important cause of buttock claudication. Congenital narrowing of the cervical canal predisposes to cervical myelopathy from minor disc protrusion.