Urodynamics are a key tool in the assessment of lower urinary tract dysfunction in spinal cord injury (SCI). However, as with many forms of urological intervention in those with SCI – it carries a risk of autonomic dysreflexia (AD). This systematic review will aim to ascertain the incidence and predictors of autonomic dysreflexia during urodynamic investigation, in those with spinal cord injury. Prior reviews have evaluated incidence of autonomic dysreflexia from iatrogenic urological triggers broadly – this review will be the first in the literature to assess risk of AD during urodynamics specifically.

This systematic review was conducted and reported in accordance with PRISMA guidelines, and was prospectively registered on the PROSPERO database (PROSPERO ID CRD420251000507) prior to data extraction. Ovid MEDLINE and Embase databases were searched with the search terms ‘Autonomic Dysreflexia’ AND ‘Urodynamics’. Risk of bias assessment was performed via the NIH Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Statistical synthesis/meta-analysis was unfeasible due to heterogeneity of definitions of AD and study populations reported – hence narrative synthesis was performed.

Of a total of 204 articles screened, 17 were ultimately included in this systematic review. Of the 17 included studies, 12 reported on incidence of AD during urodynamics, with reported incidence varyingly broadly from 7.9–90.9%. In studies reporting SCI above T6 specifically, incidence of AD during urodynamics varied from 42.5–83.7%, while in studies reporting incidence in SCI below T6, incidence varied from 5.9–82.3%. There was heterogeneity in results regarding predictors of AD during urodynamics: level of injury was generally predictive of AD incidence, completeness of injury and patient age did not predict AD incidence but did predict its severity, chronicity of SCI only predicted AD depending on definition of 'chronic', and data regarding urodynamic predictors (detrusor overactivity, detrusor-sphincter dyssynergia, compliance, and detrusor pressures) was conflicting. Varying definitions of AD accounted for the heterogenous results – with the 17 included studies using 8 different definitions of AD. Several study cohorts had a high proportion of silent/asymptomatic AD (38-63%), hence some authors suggested continuous or beat-to-beat cardiac monitoring during urodynamics in SCI patients to allow early identification and intervention for AD.

This systematic review identified the incidence of AD during urodynamics to be high, although results regarding predictors of AD in this setting were variable. Clinicians should consider continuous cardiac monitoring during urodynamics in at-risk SCI patients, and remain vigilant to risk of AD even in SCI below T6. Future studies should aim to adopt a universal definition of AD and be prospective, to permit statistical synthesis and meta-analysis to conclusively define predictors of AD during urodynamics.