Lumbar Disk Herniation: Clinical Manifestations

The S1 root syndrome includes sciatic pain (“sciatica”) from the buttock to the posterior thigh, to the posterior or lateral calf, and into the foot. When due to disk herniation, it often increases with coughing or sneezing. Numbness and paresthesias commonly occur on the lateral aspect of the foot, the sole, and the heel. Weakness, if present, is in plantar flexion of the ankle and foot. The ankle jerk is absent.

The sciatic pain of the L5 root syndrome is indistinguishable from that of the S1 root syndrome. Dorsiflexion of the foot and eversion and inversion of the ankle may be weak. The ankle and knee jerk are normal, but the internal hamstring reflex may be diminished or absent. Sensory change develops in the dorsal and medial aspects of the foot and great toe. In the less common L4 root syndrome, pain radiates to the lateral and anterior thigh. The quadriceps muscle is weak and atrophied, and the knee jerk is lost. Sensory change occurs in the anterior thigh and pretibial regions. The clinical manifestations of herniation at L4-5 and L5-S1 are summarized in Plate 4-4.

Compression of the cauda equina by a midline disk herniation or tumor may lead to bladder or bowel dysfunction, often with bilateral sciatica, saddle anesthesia, and leg weakness. This is a surgical emergency because deficits may become irreversible if treatment is delayed,

In lumbar spinal stenosis, congenital or acquired narrowing of the spinal canal or intervertebral foramina is caused by disk bulging or protrusion, bony hypertrophic changes, or thickening of the ligamentum flavum. In addition to back pain that is relieved by sitting or bending forward, symptoms include pain or other sensory disturbances occurring in one or both legs with exercise, occasionally in a radicular distribution, and resolving with rest. Such “neurogenic claudication” is distinguished from vascular claudication by the lack of any circulatory abnormality in the legs; the arterial pulses are normal.

TREATMENT

Most of the monoradicular syndromes, even those with mild neurologic deficit, respond to conservative care for several weeks; this involves a short period of bed rest (generally not more than 2 or 3 days), followed by mobilization and an exercise program. For patients with a definite diagnosis of radiculopathy secondary to a herniated disk who do not improve, options are limited. Some choose more prolonged rest, whereas some with mild symptoms may choose to return to activities of daily living despite the pain.

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