Surgical trends in the treatment of diseases of the lumbar spine in Utah's Medicare population, 1984 to 1990.

Chronic low back pain is a major source of disability in this country. The rate of surgical treatment for back disorders varies between small geographic areas in the northeastern United States. A statewide database was utilized to determine rate of surgery for mechanical low back problems in Utah's Medicare population from 1984 to 1990. The average surgery rate for Medicare enrollees was 274.7 per 100,000, and the Utah laminectomy and discectomy rates were at least 20% higher than the U.S. average. Back surgery rates rose by 55% over the study period, primarily because of increasing rates of surgery for spinal stenosis. There was statistically significant variation in surgery rates among regions in the state, with the highest region having a rate 50% greater than the lowest region. Rates of surgery for spinal stenosis had more variation than those for herniated disc surgery. There was no significant correlation between the number of surgeons performing back surgery and the rate of surgery. The variation and increase in back surgery rates in Utah's Medicare population are likely related to changes in the use of surgery for treatment of spinal stenosis and not to an increase in the number of back surgeons. Further investigation is needed to understand better the reasons for the observed increase in back surgery rates.