Background:Anterior cervical controllable antedisplacement and fusion (ACAF) is utilized for the treatment of symptomatic ossification of the posterior longitudinal ligament (OPLL). The aims of the procedure are to directly relieve ventral compression of the spinal cord, to reconstruct the spinal canal and restore cervical alignment, and to achieve satisfactory clinical recovery.Description:The detailed steps to perform ACAF have been described previously1. Briefly, following induction of general endotracheal anesthesia, a standard right- or left-sided Smith-Robinson incision is made. Discectomies are performed at the involved levels. By measuring the thickness of the OPLL on an axial preoperative computed tomography scan at each compressed level, the amount of each anterior vertebral body to be resected can be calculated preoperatively. This was, in general, equal to the thickness of the ossified mass at the same level. The previously calculated portion of each involved body in the vertebral body-OPLL complex is resected. Following the creation of a contralateral longitudinal osseous trough, the prebent anterior cervical plate is then placed, and the screws are installed after proper drilling and taping on the remaining vertebral bodies. The screws utilized in this procedure should not be too short to achieve adequate purchase in the vertebral body. Subsequently, the intervertebral cages are inserted. Thus, the vertebral body-OPLL complex is temporarily stabilized for the next procedure. Next, an ipsilateral longitudinal osseous trough is created to completely isolate the vertebral body-OPLL complex. Notably, the objective of complete isolation of the vertebral body-OPLL complex is to further anteriorly hoist the complex to decompress the spinal cord. Finally, screws are inserted through the plate and into each vertebral body and are gradually tightened to displace the bodies anteriorly. Allogenic iliac bone graft is placed in the longitudinal bone troughs to promote fusion.Alternatives:Nonoperative treatment is frequently ineffective. Traditional surgical interventions have included anterior cervical corpectomy and fusion (ACCF), posterior laminoplasty, and laminectomy2,3. ACCF focuses on resecting the ventral ossified mass in order to obtain direct decompression; however, this technique is very technically demanding, with a high risk of complications. In addition, the clinical benefits of ACCF will be limited when the OPLL extends over >3 levels. Posterior decompression can achieve indirect decompression by allowing the spinal cord to float away from the ossified mass. This technique depends largely on the preoperative presence of cervical lordosis and is contraindicated in patients with kyphosis or severe OPLL. In addition, posterior decompression surgery has been associated with a high incidence of late neurological deterioration and even revision surgery2.Rationale:ACAF combines the advantages of direct decompression as occurs with ACCF with the limited manipulation of the canal contents as occurs with the p...