Multicenter study shows previous surgery negatively affects lumbar stenosis results

Orthopaedics Today
1st on the web (February 25, 2010). Copyright ® 2010 SLACK Incorporated. All rights reserved.

Patients who undergo the typical surgical treatments for spinal stenosis can expect better results if their stenosis is at a lower lumbar level or they had no previous surgery in that area, according to findings of a multicenter, prospective, observational study.

Among the many factors the investigators examined that could impact surgical success, the location/height of the affected segment had the greatest impact on physician-based outcomes. It was associated with a 2.7 odds ratio for a good outcome for L4-L5 compared to L2-L3, said Thomas H. Zweig, MD, of Bern, Switzerland.

“Furthermore, there was a 1.7 odds ratio for an unsuccessful outcome for patients who had previous surgery on the same level,” he said at a recent meeting. “These findings can help quantify the expected outcome for surgery in patients with lumbar spinal stenosis (LSS).”

Spine Tango data

Zweig and colleagues used data from the 6-year-old European Spine Tango Registry for spine surgery for their study. The registry consists mainly of physician-rated outcomes for more than 20,000 documented surgeries conducted at 29 international centers, he said.

When the analysis was performed, 14,000 surgeries were available. From among 4,500 patients in the registry who received surgery for LSS, researchers identified 1,775 who had valid follow-up information detailed on the physician-based data collection forms.

In the study, investigators included patients treated with decompression alone or with decompression in conjunction with posterior fusion and rigid stabilization. They analyzed the patients’ American Society of Anesthesiologists (ASA) classification. About 50% of the patients were ASA class II (mild systemic disease, but no functional limitations). Interestingly, “The type of surgery had no influence, but that has to be further investigated and will be done [as part of] Spine Tango,” he said.

Factors studied

Using the McNab criteria collected from the doctors’ follow-up forms, Zweig and colleagues classified the physicians’ overall outcomes ranked “good” or “excellent” as successful cases (80%) and those that were “fair” or “poor” as unsuccessful cases (20%).

To complete a multivariate regression analysis, investigators applied several covariates assumed to influence LSS surgical outcomes, such as age, gender, spondylolisthesis as additional pathology, type of surgery performed and level treated.

Zweig told Orthopedics Today, that since Spine Tango is a consecutive, prospective and ongoing registry, the data could be re-analyzed at any time to determine longer-term effects these factors might have on surgical outcomes.

Reference:
Zweig TH, Aghayev E, Melloh M, et al. An analysis of the surgical treatment of lumbar spinal stenosis (LSS) — Procedures, outcomes, influential factors. A prospective study of 1775 patients in the international “Spine Tango” registry. Paper #51. Presented at the 36th Annual Meeting of the International Society for the Study of the Lumbar Spine. May 4-8, 2009. Miami.