National trends in lumbar facet cyst surgical management: Rising fusion utilization without improved five-year outcomes over decompression alone.

BACKGROUND CONTEXT

Lumbar facet cysts can contribute to lumbar radiculopathy and stenosis. Certain patients with lumbar facet cysts may be considered for surgical intervention, which can include decompression (D) alone or decompression with fusion (D+F). However, the use of one modality versus the other remains a topic of discussion.

PURPOSE

The current study utilized a large, national dataset to characterize yearly rates of D versus D+F utilization, identify factors independently associated with D+F relative to D, compare 90-day overall costs (measured by insurer-payments), and analyze 5-year survival to lumbar reoperation.

STUDY DESIGN/SETTING

Retrospective cohort study.

PATIENT SAMPLE

The 2010 to 2022 PearlDiver M170 database was queried for adult patients (>17 years of age) who underwent D or D+F with a same-day diagnosis of a lumbar facet synovial cyst. Exclusion criteria included multilevel fusion, coded infection, trauma, or neoplasm related to the spine within 90 days prior to surgery, and database inactivity within 90 days following surgery.

OUTCOME MEASURES

Calendar year incidence rates of D and D+F, independent predictors of D+F relative to D, 90-day postoperative insurer-payments, and 5-year survival to lumbar reoperation.

METHODS

Calendar year incidence rates for both cohorts were trended with linear regression. Multivariable logistic regression was conducted to identify independent predictors of D+F relative to D. Ninety-day postoperative insurer-payments were compared with a Wilcoxon rank sum test. To determine 5-year survival to subsequent lumbar reoperations, a 1:1 match controlling for age, sex, Elixhauser comorbidity index (ECI), spondylolisthesis, and preoperative nicotine or tobacco use was completed for the two groups. Kaplan-Meier curves for matched cohorts were created and compared with log-rank test (Mantel-Cox). Significance was defined as P < 0.0045, per Bonferroni correction.

RESULTS

A total of 45,380 patients with surgically managed lumbar facet cysts were identified, of which D alone was performed for 33,988 (74.9%) and D+F for 11,392 (25.1%). The relative incidence of decompression with fusion increased at a greater rate than D alone, such that D+F rose from 22.9% in 2010 to 29.4% in 2022 (β, slope = 0.58% per year, P < 0.0001). Multivariable analysis found D+F to be independently more likely for those with younger age (odds ratio [OR] 1.20, per decade decrease), female sex (OR 1.18), higher ECI (OR 1.06, per 2-point increase), spondylolisthesis (OR 5.04), and treatment by an orthopaedic surgeon (OR 1.29, relative to neurosurgeon) (P < 0.0001 for all). Ninety-day overall insurer-payments were greater for D+F relative to D (median: $7,744 versus $3,731, P < 0.0001). Five-year reoperation-free survival was not significantly different after matching between D versus D+F cohrots (91.5% versus 90.6%, respectively) (P = 0.6000).

CONCLUSION

Patients with lumbar facet cysts were found to be predominantly managed with decompression alone but decompression with fusion gradually increased over the study period. Factors associated with fusion included clinical (age, sex, ECI, and spondylolisthesis) and non-clinical (orthopaedic surgeon provider) variables. With similar 5-year reoperation rates between matched cohorts, careful patient selection for those most likely to benefit from fusion may optimize outcomes and resource utilization at a national level.