Pathogenesis of Lumbar Spinal Canal Stenosis Associated with Lumbar Spondylolysis, with Special Reference to the Relation between Pars Defect and Stenotic Area

Eleven patients treated surgically for lumbar spinal canal stenosis associated with lumbar spondylolysis were reviewed to investigate the pathogenesis of the lumbar nerve root involvement in spondylolysis. In accordance with the location of neural compression, spinal canal stenosis was divided into three categories; subarticular recess stenosis(five patients), central and subarticular recess stenosis (two patients) and stenosis at the pars defect (four patients). Stenosis in more than half of the patients was found to be degenerative, as it is in usual cases, rather than due to spondylolysis.