I might have a chance to be part of a group that gets surgery to insert a Dynesys screw to hold my lumbar spine in place. The surgeon would use this system to keep my spondylolisthesis from getting worse. What can I expect for results from this operation?
Lumbar spondylolisthesis (one vertebra slips forward over another) is a common cause of spinal stenosis (narrowing of the spinal canal). Older adults are affected most often. They experience disabling leg pain that makes standing and walking difficult. The leg pain may be accompanied by back pain as well.
Surgery is often needed if conservative (nonoperative) care doesn't help. The surgeon removes any bone pressing on the spinal cord or spinal nerves. This procedure is called a decompression. With the removal of the supportive bone, the spine has to be stabilized somehow.
Bone chips are usually taken from the patient's pelvis and used as graft material to fuse the spinal segment. The disadvantage of the fusion is pain at the donor site. The Dynesys system was developed to bypass the fusion.
The Dynesys is a long screw that goes through the pedicle into the vertebral body to hold it in place. The pedicle is part of the bony ring that encloses the spinal canal. This is a fairly new procedure and long-term results aren't available yet. Results after two to four years have been published.
Partial or complete pain relief was possible for most of the patients. Walking distance improved quite a bit. Two-thirds of the group were able to stop taking pain medication.
Complications include loose or broken screws and degeneration observed at the next spinal level.
The rate of change at the adjacent vertebral level appears to be about the same as reported after spinal fusion. But there is some evidence from other studies that the degeneration isn't caused by the dynamic stabilization process. It could very well just be a natural progression of aging.