Anterior Controllable Antedisplacement and Fusion as Revision Surgery After Posterior Decompression Surgery in Patients with Ossification of the Posterior Longitudinal Ligament

The aim of the present study was to evaluate the surgical outcomes of anterior controllable antedisplacement and fusion (ACAF) as a revision surgery after posterior decompression surgery (PDS) in patients with ossification of the posterior longitudinal ligament (OPLL). From June 2016 to May 2017, 15 patients (7 men; 8 women) had undergone ACAF as revision after PDS. The Japanese Orthopaedic Association (JOA) score was used to evaluate the pre- and postoperative neurological function. The kappa line and complications were also evaluated. The 15 patients were followed up for 15.1 ± 1.8 months (range, 12–18). The mean interval between the initial PDS and revision ACAF was 40.3 ± 11.3 months (range, 24–62). The JOA score improved from 8.9 ± 1.6 (range, 5–11) before revision ACAF to 13.9 ± 1.6 (range, 11–16) at the final follow-up evaluation (P < 0.05). The JOA recovery rate was 61.9% ± 15.8% (range, 37.5%–90.9%). The kappa line of 7 patients improved from negative values to positive values after ACAF. Five complications (33.3%) developed in 5 patients. No instrument failure or neurological deterioration was observed during the follow-up period. In the present study, the outcomes of ACAF for revision surgery for OPLL were satisfactory. ACAF could improve neurological function significantly and is an alternative surgical procedure for revision of PDS for OPLL.