Surgical treatment patterns among Medicare beneficiaries newly diagnosed with lumbar spinal stenosis.

Background Context: Lumbar spinal stenosis (LSS) is a prevalent degenerative condition in the elderly that can be managed medically or with surgical treatments. Recent studies have shown an increase in the utilization of surgery in the United States and great regional variations. An understanding of treatment patterns and costs in a population-based setting will help identify subgroup differences to help inform strategies for optimal care in patients with LSS.

Purpose: This study sought to examine surgical treatment rate and types, time to treatment, and patient characteristics that affect treatment patterns for newly diagnosed LSS in the US Medicare population.

Study Design: A retrospective longitudinal study of administrative claims was performed on a 5% randomly selected sample of Medicare beneficiaries.

Patient Sample: Six thousand two hundred sixty-five Medicare beneficiaries newly diagnosed with LSS in the first quarter of 2003 were identified and followed until the end of 2005.

Outcome Measures: Rate of LSS surgery, type and timing of LSS surgery, and Medicare costs.

Methods: A "de novo" LSS patient cohort was defined as those with claims with a primary diagnosis of LSS during the period of January to March 2003, excluding those with a LSS diagnosis in 2002. These patients were stratified into surgery and nonsurgery cohorts based on the presence of procedure codes for LSS surgery. The surgery cohort was further divided into three subgroups: laminectomy or laminotomy only; fusion only; and fusion with laminectomy or laminotomy. All Medicare claims for these patients were extracted and reviewed through December 2005. Descriptive statistics were carried out for demographic characteristics, comorbidities, treatment rates, and Medicare costs.

Results: This study indicated that 21% of LSS patients underwent surgery within 3 years of initial diagnosis. Surgery skews toward the healthier and younger patients. Overall, 78% of LSS surgeries were performed in the year of diagnosis, 13% in the second, and 9% in the third. Although laminectomies and laminotomies were the most frequently performed procedures across all years, a higher percentage of fusions were performed in addition to laminectomy or laminotomy in the second or third years after diagnosis than in the first year. The 3-year Medicare payments were $49,624 in the surgery cohort in comparison with $36,691 in the nonsurgery cohort. Patients who underwent a laminectomy/laminotomy alone incurred significantly lower Medicare payments ($42,293) than those who had fusion alone ($57,171) or laminectomy/laminotomy plus fusion ($63,555).

Conclusions: The surgical management of LSS varies with respect to timing and type of surgery provided. Such variation needs to be explained beyond demographic and comorbid factors.