Muscle-Specific Dosing of OnabotulinumtoxinA in Post-Stroke Upper-Limb Spasticity: A Descriptive Literature Review

BACKGROUND: Botulinum neurotoxin type A is widely used in the management of post-stroke upper-limb spasticity; however, many studies report total injected doses rather than muscle-specific dosing, limiting clinical applicability. This study aimed to evaluate how frequently muscle-level dosing protocols of onabotulinumtoxinA are reported and to assess consistency of dosing patterns across published studies. METHODS: A literature search was conducted in PubMed, Wiley/Cochrane Library, and EBSCO/CINAHL using a structured search strategy informed by PRISMA guidelines. Studies published within the last 10 years reporting on onabotulinumtoxinA treatment in post-stroke upper-limb spasticity with muscle-specific dosing data were included. Studies not providing muscle-level dosing or not allowing extraction of post-stroke upper-limb data were excluded. Data were summarized descriptively and compared across studies. RESULTS: Twenty-seven full-text articles were assessed, and five studies met the inclusion criteria. Muscle-specific dosing was consistently reported for commonly treated muscles such as biceps brachii and wrist and finger flexors, whereas other muscles were less frequently targeted. Variability in dosing between studies was observed, particularly in multicenter real-world datasets. Standardized high-dose protocols contrasted with individualized dosing strategies, which generally showed more moderate dose ranges. Expert recommendations often suggest higher doses than those observed in routine clinical practice. CONCLUSIONS: Muscle-specific dosing of onabotulinumtoxinA in post-stroke upper-limb spasticity is reported infrequently, and substantial variability exists between studies and clinical practice. Standardized reporting of muscle-level dosing and its relationship to baseline spasticity severity is needed to improve clinical applicability and reproducibility.