My 56-year old twin sister is having spinal fusion in a few weeks. The operation is going to include using interbody cages to replace the damaged disc. I'm very concerned about the long-term picture. She's still pretty young. How well do these things hold up 10 or 20 years from now?

The long-term benefits and results of interbody cage lumbar fusion (ICLF) are largely unknown. Research is limited. Much of what has been reported so far comes from the companies that designed and made the cages.

Doctors at Duke University recently reported on a group of 56 ICLF patients two years after the operation. The results were similar to low back pain patients who had other kinds of operations. They found the fusion worked just fine but the patients often had more pain and less function afterwards. Even two years later, a large number of patients were disabled and unhappy with the results.

The study found a strong link between surgery results and psychosocial factors. Depression, smoking, and a pending lawsuit are three factors most likely to cause poor results after spinal fusion. The researchers suggested patients who smoke or who are depressed should get treatment for these issues before surgery.