In this study, doctors from Japan present the results of surgery for a condition called thoracic myelopathy. Myelopathy is any damage or pressure on the spinal cord. Thoracic refers to the mid-portion of the spine between the cervical (neck) spine and the lumbar (low back) spine.
All cases were caused by ossification of the posterior longitudinal ligament (OPLL). Ossification is the change of soft tissue into bone. The PLL is a band of ligamentous tissue that runs down the length of the spine. Posterior means it’s along the back of the vertebral bones of the spine.
Surgery for thoracic myelopathy removes the back part of the bone called a laminectomy or decompression. Decompressive laminectomy for the thoracic spine doesn’t have as good of results as for cervical myelopathy. There is a major risk of paralysis with this operation.
The reason for this is that the normal thoracic spine is curved forward so it’s difficult to take pressure off the spinal cord. After a decompressive laminectomy, the natural curve keeps the spinal cord pushed backward with a greater chance for continued pressure on the cord. The ribs also tend to get in the way when performing the surgery from behind the spine (posterior).
Over the years the surgeons doing this study have used three different surgical methods to treat OPLL. They describe each operation and the results over time. The three procedures are:
The authors say the risk of spinal cord damage is the highest when posterior decompression is done by laminectomy alone. Paralysis can occur early right after surgery or much later. When decompression or extirpation is done, fusion with the hook and rod system is advised.
If paralysis occurs after decompression, the surgeon can do a second operation to fuse the spine. Based on their experience with 51 OPLL patients, the authors offer surgeons specific guidelines for choosing the best surgical method for each patient.