Expansive laminoplasty can be performed to treat cervical myelopathy in the ossification of posterior longutitional ligament (OPLL) and cervical spondylotic myelopathy (CSM).
Our retrospective study used 18 patients' CT films and measured spinal canal area, spinal canal distance, and the respective evaluations (used by JOA-Score). The result shows that the expansion of the spinal canal was not related to the JOA-Score, but expantion of the spinal canal area and spinal canal distance has a significant relation.
The lower cervical vertebrae has a wide spinal canal by nature, and so expansion is shignt compared the other spines.
This operative method involves cutting off the procesus and openning the lamina. Use of a small spacer will not provide sufficient expansion due to a small lamina angle.