A study from the Oregon Health and Science University has found that complex spinal operations for seniors with lower back problems rose 15-fold between 2002 and 2007. This occurred even though the incidence of lower back problems remained steady during this period and with little evidence that these operations are beneficial to patients.

Back problems among seniors are largely the result of spinal stenosis, a narrowing of the spinal canal, the space inside of the spinal column. This space isn't very large to begin with. As people age, it tends to shrink, often due to bone spurs or enlargement of spinal discs. This shrinkage may not cause any symptoms. If it places pressure on any of the nerves running up and down the spinal column, it can cause a host of painful problems.

There are three general types of surgical procedures that can be used when stenosis leads to pain. These are decompression, simple fusion and complex fusion. Decompression is probably the least controversial of all back operations. Its goal is to remove any offending material pressing on nerves that may be causing pain. This may involve shaving a bone or removal of bone fragments, portions of a bulging spinal disc or material that has leaked out from inside of a disc.

Simple fusion is usually the welding together of two spinal vertebrae, the bones that run along the spinal column. This is most often done when one specific vertebra has become enlarged or displaced. Complex fusion may involve a variety of artificial implants and/or attachment of multiple vertebrae or two vertebrae at multiple sites. Spinal fusion is a much more controversial operation than decompression is. There is little evidence that complex spinal fusions are more effective than simple ones are.

The study limited itself to looking at Medicare claims for operations for lumbar (lower back) stenosis from 2002-2007. Stenosis in the lower spine most commonly leads to pain or cramping in the leg or calf. Complex fusions were once rare, but rose over 15-fold in Medicare patients between 2002 and 2007, from 1.3 per 100,000 patients to 19.9 per 100,000. Yet the total number of operations for lumbar spinal stenosis actually decreased in this period.

The surgical literature doesn't seem to justify this large increase in the number of complex operations (complex fusions). The more invasive the spinal surgery is, the more likely it is to be accompanied by complications, and the more expensive it becomes. 5.6% of all patients in the study who underwent complex fusion procedures suffered life-threatening complications, compared to 2.3% of those undergoing decompression operations, the simplest type of spinal surgery. Average hospital costs for complex fusions were $80,888, compared to $23,724 for decompression operations.

So why are so many complex fusions being performed?

Richard Deyo, lead author of the study, suggests that both financial considerations and pride are driving the increase: "Financial incentives to hospitals and surgeons for more complex procedures may play a role as may desires of surgeons to be local innovators." Hospitals and surgeons are paid more for complex procedures. Deyo also suggests that "many surgeons genuinely believe that more complex procedures are more advantageous," but that view is "shaped heavily by manufacturers of surgical implants and devices."

In other words, this increase is not only about the needs of the patient.

The study suggests that both surgeons and patients need to look more carefully at whether it makes sense to treat a particular case of lumbar stenosis by complicated means.

A report detailing the study was published in the April 7, 2010 issue of the Journal of the American Medical Association (JAMA).

Richard A. Deyo, MD, MPH, is a professor of family medicine and internal medicine at the Oregon Health and Science University.