Antedisplacement and fusion (ACAF) as a revision surgery following initial posterior decompression for cervical spondylotic myelopathy caused by ossification of the posterior longitudinal ligament

Ossification of the posterior longitudinal ligament (OPLL) is a progressive condition that may lead to late neurological deterioration even after successful posterior decompression. Although posterior approaches such as laminoplasty and laminectomy with fusion are commonly performed, some patients ultimately require revision surgery due to progressive kyphosis or enlargement of the ossified lesion. The anterior controllable antedisplacement and fusion (ACAF) technique offers a novel solution by enabling controlled anterior migration of the ossified mass without direct resection. This study aimed to evaluate the clinical and radiographic outcomes of ACAF as a revision procedure for OPLL following failed posterior decompression. This single-center retrospective study included 40 patients who underwent ACAF revision surgery between 2018 and 2024 after prior posterior decompression (laminoplasty or laminectomy with or without fusion). All patients underwent pre- and postoperative radiographic evaluation (X-ray, CT, and MRI) and were followed up. Operative parameters (operative time, estimated blood loss), complication rates, neurological function (Japanese Orthopaedic Association [JOA], Visual Analog Scale [VAS], Neck Disability Index [NDI] scores), and radiographic parameters (C2–7 angle, segmental lordosis, anterior shift of ossified mass, spinal cord drift, and rotation angle) were analyzed. The interval from initial posterior surgery to revision was comparable between the laminoplasty-ACAF and laminectomy-ACAF groups. Operative time and blood loss also showed no significant differences between groups. Each group had one case of C5 nerve root palsy, both resolving within six months, while cerebrospinal fluid leakage occurred slightly more often in the LMP-ACAF group. At final follow-up, both groups showed significant improvements in JOA, VAS, and NDI scores, with no intergroup differences. Radiographically, cervical alignment and segmental lordosis improved significantly in both groups, without implant-related complications or restenosis. Measures of ossified mass displacement, spinal cord drift, and rotation angle were similar across groups. The overall fusion rate was favorable, with slightly higher rates in the LMP-ACAF group. Subgroup analysis excluding prior instrumented fusion cases confirmed sustained significant improvements in cervical alignment. As a revision strategy, ACAF demonstrates encouraging clinical and radiological outcomes in this selected cohort. These preliminary findings suggest ACAF may be a viable surgical alternative for managing OPLL in patients with failed prior posterior decompression, though confirmatory comparative studies are needed.