Rates of Lower Back Surgery Vary to 20-Fold, Ten-Year Review Finds

Study Shows Wide Regional Variations in Spinal SurgeryRates of Lower Back Surgery Vary to 20-Fold, Ten-Year Review FindsNewswise — Rates of lower back surgery among older adults—especially for an increasingly frequent procedure called lumbar fusion—vary widely across different regions of the United States, reports a study in the Nov. 1 issue of Spine (http://www.spinejournal.com).

Although the study can't explain the reasons for the variation, the findings raise concerns about the quality of the scientific evidence on back surgery in general and lumbar fusion in particular, according to a research group from Dartmouth Medical School. The lead author was Dr. James N. Weinstein, Chairman of Orthopaedic Surgery and Professor in Community & Family Medicine and Senior member of the Center for the Evaluative Clinical Sciences at the Dartmouth-Hitchcock Medical Center and Dartmouth Medical School. Dr. Weinstein is also Editor-in-Chief of Spine, the leading peer-reviewed journal on the study of the spine.

The researchers analyzed nationwide data on rates of lumbar spine (lower back) surgery among Medicare recipients aged 65 and older, between 1992 and 2003. The results showed a dramatic increase in spinal surgery during this time—in 2003, Medicare spent over $1 billion on spinal surgery.

There was a particularly sharp increase in the rate of lumbar fusion surgery—an operation performed to fuse adjacent vertebrae together—after the introduction of a new surgical implant device in the mid-1990s. The average rate of lumbar fusion doubled from 0.3 to 1,000 Medicare enrollees in 1993 to 0.6 per 1,000 in 1998, increasing further to 1.1 per 1,000 enrollees in 2003. As a percentage of total Medicare spending for back surgery, lumbar fusion increased from 14 percent in 1992 to 47 percent in 2003.

The study also found wide variation in rates of lower back surgery among Medicare recipients living in the 306 different U.S. hospital referral regions. Rates of lumbar discectomy and laminectomy—procedures commonly performed for patients with disc-related back problems—varied 8-fold across regions. For spinal fusion, the variation was even greater—20 times higher in some regions than others. This was much larger than the variation for other major operations in older adults, such as hip replacement or surgery for hip fracture.

Regions with lower rates of back surgery in the 1992-93 tended to have low rates in 2002-03 as well. The variations were unrelated to the regional supply of orthopedic surgeons and neurosurgeons. Regions with high rates of spinal fusion included Idaho Falls, Idaho, Missoula, Mont., and Mason City, Iowa. The lowest rates were found in Bangor, Maine, Covington, Ky., and Terre Haute, Ind.

The study permits no conclusions about why the variations in back surgery rates are so high—likely contributors include "lack of scientific evidence, financial incentives and disincentives to surgical intervention, and differences in clinical training and professional opinion," the authors believe. The variation is unlikely to be related to patient preferences; rates sometimes vary substantially even for neighboring, demographically similar regions.

Dr. Weinstein and his fellow researchers voice concern about the quality of research evidence regarding back surgery, particularly lumbar fusion. "The scientific evaluation of outcomes for spine surgery has not kept up with the changes in operative techniques," they write.

In the absence of high-quality research, "Major surgery is often conducted without an adequate scientific basis for making a reasonably accurate estimate of the likely outcomes," Dr. Weinstein and colleagues write. They urge redoubled efforts at effective assessment of medical technologies, concluding, "The mobilization of talent and focus of interest required to meet the larger task of improving the scientific basis of everyday practice will require the active participation of the funding agencies and academic medical centers."

About SpineRecognized internationally as the leading journal in its field, Spine (http://www.spinejournal.com) is the leading subspecialty journal for the treatment of spinal disorders. Edited by Dr. James N. Weinstein, Chairman of Orthopaedic Surgery and Professor in Community & Family Medicine and Senior member of the Center for the Evaluative Clinical Sciences at the Dartmouth-Hitchcock Medical Center and Dartmouth Medical School, the Journal is affiliated with major specialty societies worldwide, including the Argentine Society for the Study of Spine Pathology · Asia Pacific Orthopaedic Association - Spinal Section · Cervical Spine Research Society · Chinese Orthopaedic Association · Finnish Spine Research Society · International Society for the Study of the Lumbar Spine · Japan Spine Research Society · Korean Society of Spine Surgery · Scoliosis Research Society · Spine Section of the Hellenic Orthopaedic Association · Spine Society of Australia · Spine Society of Europe (Affiliate).

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