RESUMEN
Preoperative diagnosis of free disc fragment is important in order to avoid treatment by chymopapain and percutaneous method of disc removal or anterior discectomy. This retrospective case analysis was to study the cause, physical findings and appropriate investigation to identify free disc fragment before surgery. One hundred and thirteen operative patients of herniated lumbar disc were studied. Of these, eleven patients (9.7%) were diagnosed with free disc fragment. The results revealed that one patient was diagnosed preoperatively with free disc fragment by myelography and MRI and three other patients using MRI alone. We concluded that preoperative diagnosis of free disc fragment can be made through identification of a large myelographic defect and/or sagittal scan MRI showing migration of disc material from native disc space.