Comparing Surgical Costs for Adult Spinal Deformity: Posterior-Only Versus Combination Anterior-Posterior

31st Annual Meeting of the North American Spine Society Highlight

As the U.S. aging population increases, the prevalence of adult spinal deformity (ASD) and the need to treat it will also continue to rise. ASD surgical treatments are costly and opinions vary on the best approach. Researchers compared a posterior-only approach to a combination surgical anterior-posterior technique to determine which was most cost effective. Jeffrey L. Gum, MD, presented the results of the study at the 31st Annual Meeting of the North American Spine Society, October 26-29, in Boston.
Man touching a compare concept on a touch screen with his fingerDr. Gum and his team used a database of spinal deformity centers with a minimum two-year follow up. Photo

Adult Spinal Deformity’s Economic Impact

ASD was the ninth most costly condition in United States in 2011, Dr. Gum said. He also noted treatments for these cases cost nearly $76 billion each year in the United States, and they account for 6% of all health care dollars.

“This makes it very important for us to show value for ASD surgery,” said Dr. Gum, who practices spine surgery at Norton Leatherman Spine Center in Louisville, Kentucky. “The way we show value, or cost effectiveness, is dividing cost over outcome.”

In addition to the economic impact, ASD surgery has a high variability among spine surgeons. The study aimed to understand whether posterior-only or a combination anterior-posterior technique when performing a long-instrumented fusion would emerge as an optimal treatment both from a cost and quality perspective.

“If you get 10 deformity surgeons in a room trying to come up with a surgical plan for a case, you’ll most likely get 10 surgical plans if not more,” Dr. Gum said.

Comparing Posterior-Only to Anterior-Posterior for ASD Treatment

The goal of the study was to compare the cost effectiveness of posterior-only versus an anterior-posterior combination approach when performing long-instrumented fusions for ASD, specifically to determine the two-year cost per quality-adjusted life year (QALY) for each approach.

Dr. Gum and his team used a prospective, multi-center, operative, and nonoperative database of spinal deformity centers with a minimum two-year follow up. All patients were adults with radiographic evidence of ASD who had long-instrumented fusions either from posterior-only or using an anterior-posterior approach. The researchers identified the QALYs gained by the two groups by reviewing baseline, one-year, and two-year postoperative SF-6D scores.

The team calculated costs using direct costs from the hospitals, which included any readmissions or revisions within the two-year period. An important point of distinction for this study is Medicare allowable rates were not included in the cost analysis—only actual direct hospital costs.

Out of 196 patients eligible for a two-year follow up, 163 (or 83%) had complete baseline data. Of those 163, the researchers had complete cost and quality data for 117 patients. Of those 117, 72 had a posterior-only approach and 45 had an anterior-posterior approach. Across the two groups of patients, there was no difference in sex, age, BMI, ASA score, or Charlson Comorbidity Index. There was also no difference in levels fused, BMP use, or decompression.

QALYs gained were similar for both posterior-only and anterior-posterior patients. Comparing index surgery costs revealed a $20,000 difference: $64,000 was the mean cost for posterior-only, while anterior-posterior was $84,000. That margin decreased $16,000 when the researchers reviewed two-year costs, which included revision ($73,000 for posterior-only and nearly $90,000 for the combination approach). Revision rates also saw no difference between surgical approaches (24% for both groups).

Posterior Appears More Cost Effective, But a Long-Term Review is Needed

Given the findings of this study, outcomes were similar regardless of approach; a posterior-only approach costs less than anterior-posterior combined.   

Dr. Gum identified the two-year follow up as the biggest limitation of the study, so a longer-term review of outcomes is necessary to understand the true value of posterior-only versus the anterior-posterior approach.

“It’s important to demonstrate value in adult spinal deformity—this may help reduce variability and optimize care,” Dr. Gum said. “When you compare posterior-only and combined posterior-anterior approaches in ASD surgery, posterior-only is more cost effective, at least under our study parameters.”

To view additional meeting highlights from the 31st Annual Meeting of NASS, click here.

Updated on: 03/19/19
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