Operative treatment of spondylolisthesis in young patients.

In a series of 91 patients under 20 years of age with lytic spondylolisthesis treated by different operations, 66 (73%) showed a displacement of more than 30 per cent at admission. If the displacement exceeds 30 per cent, it often progresses to a subtotal olisthesis. Spinal fusion should be performed before the displacement exceeds a third of the length of the vertebra. A posterior fusion with two massive tibial grafts was carried out in 78 patients (87.5%). Concurrent with fusion laminectomy was performed in 18 patients. Anterior vertebral body fusion was performed in 3 patients and posterolateral fusion in 10, in 4 of these as a secondary operation. Laminectomy alone was carried out in 4 patients, 3 of these having a total olisthesis. Laminectomy without fusion should be performed only in exceptional cases in young patients. Non-union or uncertain union after the primary operations occurred in 17 cases (19.5%); 15 reoperations were performed in 13 patients. The degree of displacement at operation did not influence the results. A progression of displacement despite dorsal fusion was observed in 14 patients. The final results of operative treatment were: good in 55 patients (60.4%); satisfactory in 23 (24.1%); unsatisfactory in 13 (15.5%). Posterolateral fusion seems to be preferable to posterior fusion.