Real-world complications, utilization patterns, and patient selection for the vertiflex interspinous process device: A national cohort analysis

Background context: The Vertiflex interspinous process device (IPD) offers a minimally invasive alternative for moderate lumbar spinal stenosis (LSS) and is the only FDA-approved stand-alone interspinous spacer. While initial trials demonstrated favorable short-term outcomes, concerns remain regarding long-term efficacy, high revision rates, and patient selection criteria. Purpose: To evaluate complications, utilization trends, and patient selection patterns for Vertiflex IPD using a national insurance database. Study design: Retrospective cohort study using a national insurance claims database. Patient sample: Patients undergoing Vertiflex IPD placement between 2017 and 2023 were identified from the PearlDiver Mariner Database. For comparative analyses of patient selection and annual utilization trends, a reference cohort of patients who underwent single or multi-level lumbar laminectomy or laminotomy without fusion was identified. Outcome measures: 30-day complications, two-year reoperation rates, predictors of reoperation, predictors of IPD utilization compared to lumbar laminectomy/laminotomy, trends in opioid use, and relative annual utilization were investigated. Methods: Univariate logistic regression and multivariable logistic regression controlling for age, gender, and Elixhauser Comorbidity Index (ECI) were used to evaluate patient factors as predictors of Vertiflex IPD selection and reoperation following Vertiflex IPD placement. Two-year cumulative incidence of reoperation was estimated using Kaplan-Meier survival analysis. Bonferroni correction was applied for multiple comparisons (significance threshold p < 0.0042). Results: A total of 6321 patients underwent Vertiflex IPD placement, with 42.2% receiving multi-level implants and 92.5% of procedures performed by pain medicine physicians. The cohort had a mean age of 71.8 ± 8.8 years, mean ECI of 6.6 ± 3.9, and was 55.4% female. Predictors of Vertiflex utilization compared to surgical decompression included older age (70-79: aOR 2.29; 80-99: OR 3.54) female gender (aOR: 1.60), Medicare (aOR: 1.68) or Medicaid insurance (aOR: 1.28), residence in the West (aOR: 1.49) or Southern U.S. (aOR: 1.26), and a higher comorbidity burden, defined as ECI ≥5 (aOR: 1.45) (all p < 0.01). The Kaplan-Meier two-year cumulative incidence of reoperation was 6.30%. Opioid utilization decreased from 54.28% at baseline to 29.44% at 12 months (absolute reduction 24.84%, p < 0.001). Vertiflex usage rose from 0.21% of total decompressions in 2017 to 1.57% in 2020, then declined to 0.80% in 2022. Conclusion: Vertiflex IPD is predominantly used in older patients with greater comorbidity burden compared to those undergoing surgical lumbar decompression, consistent with selection of a less-invasive option for higher-risk patients. The two-year reoperation rate observed in this real-world cohort (6.30%) is lower than earlier FDA trial reports; however, cross-study comparisons were not risk-adjusted and should be interpreted with caution.