Point of View

Over the past 15 years, Deyo and his colleagues at the University of Washington have refined the techniques to study large regional and national databases relevant to the treatment of low back disorders. Despite some methodological limitations (sampling and recording errors), these databases give a reasonably accurate picture of national trends in spinal surgery. Deyo et al confirm that the annual rate for spinal fusion has been growing rapidly, particularly as that operation is used for the treatment of degenerative disc disease and for spinal stenosis in the population over 60 years of age. The growth trajectory accelerated even further following the Food and Drug Administration approval of fusion cages in 1996, far exceeding the annual growth rates for total hip and knee replacements. One of the few benefits of aging is that you have lived through historical changes that may help inform current events. When I was a resident, surgery for hip arthritis was relatively rare because the risks of operation were significant and the benefits uncertain. Only young men with unilateral disease were eligible for hip fusion; cup arthroplasty required highly motivated, relatively thin patients; femoral prosthetic replacements often failed with time; and the results of osteotomy and “hanging hip” were unpredictable. The advent of total hip replacement (THR) was a revolutionary advance with predictable and excellent functional results obtained in patients with disabling arthritis of the hip. The annual rates for THR grew rapidly as more surgeons learned the techniques, as referring physicians became aware of the excellent results, and as patients with arthritis learned from the media and friends about the operation. THR went from an operation limited to a few centers, to an operation performed in all but the smallest hospitals. With that growth came enhanced awareness of the complications and longer term problems that caused failures, as well as a better appreciation the durability of total hip operation in properly selected patients. Today, the annual rates of THR and total knee replacement remain significantly variable as a function of geographic location, but the relative risk for surgery appears to be fairly constant from year to year. Is it possible that we are seeing a similar evolution in surgery for lumbar spinal degeneration? Since the introduction in 1911 of spinal fusion techniques by Hibbs and Albee, there have been a variety of operations developed to treat degenerative spinal conditions. When a diagnosis of spinal stenosis is evident, the benefit of decompression versus decompression with fusion has been contested with few studies to scientifically inform that debate. When low back pain has been the predominant complaint, spinal fusion has been advocated. Initially, surgeons have been enthusiastic about new fusion techniques (facet, intertransverse process, anterior interbody, posterior interbody, and circumferential {360 degree} fusion techniques) only to discover the longer term results often were unpredictable and disappointing. New internal fixation devices also have been touted as the latest breakthrough in the management of low back disorders. Some of these devices, most notably the pedicle screw, may have enhanced the rate of biologic fusion but not necessarily the clinical results. Moreover, these devices have also been associated with increased morbidity, blood loss, and the risk of further surgery particularly in older patients. The introduction of the cage had been hailed as the latest advance in spinal surgery. Deyo et al infer but cannot prove a causal relationship between the introduction of the cage in 1996 and the ensuing rapid increase in the annual rate of lumbar spine surgery. It would be fortuitous if the results of this new technique are so good that we are now observing a phenomenon similar to rapidly growing surgical rates that followed the introduction of total hip replacement? Alas, that seems unlikely. Patients with degenerative hip disease usually present with a typical history and characteristic physical findings. Radiographs of the hip confirm the clinical diagnosis and only rarely are further studies required. In contrast many patients with degenerative spinal conditions have a history of nonspecific back pain and nonspecific physical findings. Even when there is a classic history of stenosis (claudication, forward flexed posture), the physical examination is limited in its ability to localize the level(s) of possible involvement. Confirmation of a specific, localized clinical diagnosis by plane radiography is difficult with the exception of degenerative spondylolisthesis. As Kellgren and Lawrence observed, most patients over age 60 have radiologic evidence of lumbar From the Department of Orthopaedic Surgery, University of Vermont, Burlington, Vermont. The manuscript submitted does not contain information about medical device(s)/drug(s). No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript. Address correspondence to John W. Frymoyer, MD, Department of Orthopaedic Surgery, University of Vermont, Burlington, VT 05401; E-mail: Tofrys@aol.com