What's the "catch" in upper-limb post-stroke spasticity: expanding the role of botulinum toxin applications

More than a third of stroke patients will develop post-stroke spasticity, especially involving the paretic upper limbs. Despite established, intensive rehabilitation programmes in place, spasticity may still affect a post-stroke patient's quality of life and create economic and caregiver burdens. Hence, there is a need to explore how botulinum toxin (BTX) therapy may further improve patient outcomes. Consensus guidelines on the clinical use of BTX for established and symptomatic upper-limb spasticity are now available. While BTX therapy has been universally shown to reduce muscle tone in spasticity, its corresponding improvement in functional-outcome measures are far from consistent. This review article attempts to analyse the reasons for the inconsistency and makes the case that improved and reliable functional outcomes after BTX therapy may be achieved when: patient-specific goals that incorporate realistic expectations (such as improving passive as well as active functions and reducing pain) are used as functional-outcome measures; patients are followed up over a reasonable amount of time so as to optimise learning, rehabilitation and possibly even allow plasticity to occur; and, correct and thoughtful muscle targeting that considers various factors, such as spread, technique and avoidance of compensatory muscles, is employed. This article also summarises the characteristics of post-stroke patients who are at greatest risk for developing spasticity and those who are most likely to become the "best responders;" and, it attempts to outline the potential advantages of early BTX therapy in the acute to sub-acute post-stroke period, while spasticity is still evolving.