Abstract
Spondylolisthesis without a defect in the neural arch, the "pseudo-spondylolisthesis" of Junghanns, usually affects the fourth lumbar vertebra. The essential lesion is an increase in the angle between tile inferior facets and the pedicles which allows subluxation at the inferior joints. The forward displacement averages less than one centimetre. It commonly produces a clinical picture of backache and sciatica, but may present with. a "drop foot," and in unusual instances compression of the cauda euluina may occur. Patients seen in the early stages without signs of nerve root compression are best treated by localised spinal fusion. Late fusion may afford no relief because of secondary changes in the spine, but these patients obtain some benefit from a corset. Laminectomy is indicated for severe symptoms in patients who show signs of nerve root compression; it should be followed by spinal fusion.