Multiple lumbar spondylolyses.

Spondylolysis of more than one lumbar vertebra occurring in the same individual is rare. The incidence of multiple lumbar spondylolyses appears to vary between 1.2% and 5.6%. Most cases respond to conservative treatment. When surgery is indicated, it must be radical, and the fusion should include all the defects and the intervening normal vertebrae and the sacrum. The condition is more common among men, and trauma plays a major role in its initial appearance.