To determine whether the presence and severity of cerebral small vessel disease (CSVD), measured by Fazekas scores, are independently associated with functional outcomes after traumatic brain injury (TBI).

TBI remains a leading cause of disability worldwide, yet reliable predictors of long-term outcomes are limited. Microvascular dysfunction has been proposed as a key mechanism of post-traumatic impairment. We hypothesized that pre-existing CSVD is associated with worse functional recovery following TBI.

We retrospectively reviewed adults (≥18 years) evaluated for post-TBI deficits at Mayo Clinic Florida (2010–2024) with available MRI. CSVD burden was graded using Fazekas deep white matter (FD) and periventricular (FPV) scores (0–3). Functional outcome was assessed by the modified Rankin Scale (mRS) within 12 months post-injury. Univariable and multivariable logistic regression identified predictors of poor outcome (mRS 3–6). Ordinal regression assessed associations between Fazekas scores and the full mRS distribution.

Ninety-seven patients (mean age 52.1 ± 22.9 years; 56 females) were included. Inter-rater reliability was high (κ = 0.90 FD, κ = 0.93 FPV). Higher Fazekas scores correlated with older age, vascular risk factors, and cognitive impairment (p < 0.001). In multivariable models, age independently predicted poor outcome (OR = 1.34 per year, p = 0.001). Both FD and FPV remained significant predictors of worse mRS outcomes after adjustment (FD: aOR = 2.83, p = 0.019; FPV: aOR = 2.85, p = 0.002). A dose-dependent effect was noted, with all deaths occurring in patients with FD ≥2 or FPV ≥3.

Pre-existing CSVD, quantified by Fazekas-rated white matter hyperintensities, is independently associated with poorer neurological outcomes after TBI. White matter lesion burden may serve as a potential imaging biomarker for prognostication and rehabilitation planning in TBI care.