Multi-centre Study to Evaluate ACAF Versus Laminoplasty in Treating Cervical Ossification of the Posterior Longitudinal Ligament

(1)A standard right-side Smith-Robinson approach is performed. (2) The involved disc tissues are removed. The posterior longitudinal ligament is cut down at the levels cephalic and caudal to OPLL. (3) The anterior portion of the middle vertebral bodies is removed according to the thickness of ossification. Suitable cages are placed into each intervertebral space. (4) On the left side of the vertebra, a 2-mm-wide groove is created at the medial border of the transverse foramina. After that, an curved plated is fixed with screws. (5) On the right side of the vertebrae, a similar groove was also created. (6) Finally, tightening the screws to achieve a gradual evaluation of the vertebrae with OPLL.

(1) In the prone position, the skin and nuchal ligament were cut through the posterior median incision, and the paravertebral muscles were stripped layer by layer to expose the bilateral vertebral lamina, lateral mass and articular process.（2) Part of spinous process were removed with bone biting forceps. The side with more severe symptoms was selected as the open side, bone groove was performed at 2-3 mm of the medial edge of bilateral facet joints with the medial cortex was reserved at the shaft side.（3) Slowly lift the lamina and maintained.（4)Determining the opening width of each segment by trial, and selecting the appropriate size Arch miniplate, and fixed with screws.