If you're having surgery for degenerative disc disease of the cervical (upper) spine, the technique your surgeon uses may depend on what part of the country you live in, suggests a study in the January issue of Spine. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health.

Persistent regional variations highlight the need for solid scientific research on the techniques and outcomes of cervical spine surgery, according to the new report by Dr Kevin J. McGuire of Beth Israel Deaconess, Boston, and colleagues.

As Number of Procedures Increases, Regional Variations Persist

The researchers analyzed data from a quality improvement project of the American Board of Orthopedic Surgeons, in which Board-certified surgeons provided information on all surgeries performed over a six-month period. Data from 1999 to 2008 were analyzed to track trends in the rates and types of surgery for degenerative cervical disc disease.

The study focused on a procedure called cervical spinal fusion, or anterior cervical discectomy and fusion (ACDF). In this procedure, the diseased disc between two vertebrae is removed and the vertebrae are fused together using bone grafts, hardware, or other techniques. Alternatively, an artificial disc may be implanted between vertebrae, without fusing the vertebrae.

During the decade studied the number of cervical fusions performed by Board-certified orthopedic surgeons increased by two-thirds, while the number of surgeons performing these procedures increased by nearly half. The number of surgeons who described themselves as spine surgeons increased by about one-fourth, while the number who said they were general orthopedic surgeons decreased by one-fourth.

As in previous studies, the techniques used to perform ACDF varied between different U.S. regions. For example, surgeons in the South and Southeast were more likely to use artificial disc implants than Midwest surgeons. The use of metal plates was lower for surgeons in the Northeast but higher in the Southeast. Midwest surgeons were more likely to use bone substitutes (allograft) than the patient's own bone (autograft). Complications were more common when autograft was used.

Variations Highlight Need for More Research Data

Overall rates of spine surgery in the United States have increased substantially in recent years. While spinal fusion is more commonly performed in the lower (lumbar) spine, about 40 percent of fusion procedures are done in the cervical spine. Previous studies have reported "enigmatic regional variations" in the rates of cervical spine surgery significant differences in rates and techniques, with no apparent basis in research evidence.

The new study suggests that these variations persist while the number of cervical fusion surgeries increases. Since there has been little change in the population rates of cervical disc disease, "[O]ne must question the increase in surgical rates among orthopedic candidates, and continued regional variations in the types of procedures," Dr McGuire and colleagues write.

These trends underscore the need for more evidence on the effectiveness of cervical spinal fusion surgery especially since studies suggest that about half of patients will improve without surgical treatment. There is also a lack of comparative data on which surgical technique provides the "best" results.

The study has some important limitations including the fact that it provides no information on procedures performed by neurosurgeons. However, the results suggest that decisions about whether and how to perform cervical spinal fusion are being made based on factors other than scientific evidence. Dr McGuire and coauthors conclude, "The challenge of new technologies and the lack of evidence about comparative effectiveness...limit our ability to provide an informed choice to patients facing preference-based decisions."