Rising Use of Ultrasound-Guided Carpal Tunnel Injections: National Trends, Drivers of Utilization, and Outcomes

Purpose: Carpal tunnel syndrome may be considered for carpal tunnel injection (CTI). Ultrasound (US) guidance has been proposed to improve CTI accuracy, but the trend across the years, factors associated with utilization, and outcomes are not well characterized. Methods: Patients undergoing CTI with or without US guidance were identified from the PearlDiver M170 database (2010-2022). The trend of US-guided CTI was assessed by linear regression. Patient demographics and provider specialty were compared by multivariable analyses. Two-year survival to repeat injection and carpal tunnel release (CTR) were assessed by univariable and multivariable analyses. Results: Of 478,645 patients undergoing CTIs, US guidance was used for 62,525 (13.1%). Over the years, this utilization increased from 3.6% to 17.1% (β = 0.97 %/year).Factors statistically significantly associated with US utilization were region (relative to South, Northeast: odds ratio [OR] = 1.62, West: OR = 1.08, Midwest: OR=1.06), Medicare insurance (relative to commercial, OR = 1.07), higher Elixhauser Comorbidity Index (OR = 1.04), and younger age (OR = 1.03 per decade). Relative to hand surgeons, lower utilization was noted for other orthopedic surgeons (OR = 0.71) and plastic surgeons (OR = 0.04), and higher utilization was noted for multiple specialties, led by physical medicine and rehabilitation (OR = 9.36) and anesthesia (OR = 8.34).US guidance was associated with higher incidence of repeat CTI (15.0% vs 12.9%, OR = 1.37). In unadjusted analyses, CTR incidence was lower following US-guided CTI (31.1% vs 37.8%). However, when controlling for provider specialty, the direction of this association reversed, with greater odds of CTR following US-guided CTI (OR=1.21). Conclusions: Utilization of US-guided CTI increased from 2010 to 2022. The association with nonclinical drivers suggests lack of therapeutic consensus. Although unadjusted analyses revealed lower CTR incidence following US-guided CTI, the reversal of this association after controlling for provider specialty highlights the influence of provider-level variability and room for algorithm-driven care pathways. Type of study/level of evidence: Retrospective cohort, therapeutic IIc.