Long-term functional and radiographic follow-up of surgically treated isthmic spondylolisthesis

We studied patients treated surgically for isthmic spondylolisthesis since 1968, with special emphasis on a detailed functional assessment. We followed up 22 patients for an average of 15 years, with a mean age at time of surgery of 18 years. All patients underwent a thorough physical examination and were evaluated with radiographs at baseline and at follow-up. The functional status of patients at the time of follow-up was assessed with 2 self-report pain and function instruments. All surgical procedures included spinal fusion, 12 of which included internal fixation by using Harrington distraction rods with sacral bars. At final follow-up, there was no statistically significant difference in mean slip percentage or mean slip angle compared with baseline radiographs. Functional evaluation was compared with a control group consisting of 52 patients. We conclude that the long-term radiographic and functional outcome is excellent for patients treated surgically for isthmic spondylolisthesis.