Cauda equina lesions following fusion in situ and decompressive laminectomy for severe spondylolisthesis. Four case reports.

The authors report four cases of cauda equina lesions following posterior surgery for severe dysplastic spondylolisthesis: three following fusion in situ, and one following decompressive laminectomy. The patients developed urinary retention, saddle anesthesia, and lax anal tone immediately after surgery. The mechanism of the nerve root damage is thought to be mechanical, occurring during decortication before bone grafting. It is recommended that patients should be counseled about the risk of neurologic impairment following decompressive laminectomy or fusion in situ for severe spondylolisthesis.