Efficacy of botulinum toxin A for the treatment of hemiparesis in adults with chronic upper limb spasticity.

Introduction: this study aimed to evaluate the effectiveness of botulinum toxin A (BoNT-A) injection in hemiparetic patients with chronic spasticity in the upper limb resulting from stroke or traumatic brain injury.

Methods: we conducted a retrospective study including 45 patients seen, in our department of Physical Medicine and Rehabilitation, between January 2014 and December 2016. All patients received an injection of BoNT-A (Dysport, 100 U/ml). Affected upper-extremity muscles could be injected as per the investigator's discretion to a maximum total dose of 1000 U. We evaluated muscle tone using Modified Ashworth Scale (MAS). Functional disability was assessed using Modified Frenchay Scale (MFS), Nine Hole Peg Test (NHPT) and Barthel Index (BI). Quality of life (QoL) was assessed using the 36-Item Short Form Health Survey (SF-36). The achievement of treatment goal was assessed by the Goal Attainment Scaling (GAS).

Results: patients decreased their MAS score over the first and the third months (p<0.05). MFS showed improvement at 1 month after injection with a median change from baseline of 8 (range: 1-16; p<0.001). The change from baseline ranged from 0 to 5 points for NHPT at 1 month after injection (p< 0.001). This functional improvement was maintained to 3 months. Improvements in Barthel Index was observed at 3 months with a median change from baseline of 5 points (range 0-15; p<0.001). The mean change from baseline of SF-36 score was 4.77 ± 3.39 (p<0.001). The mean GAS T-score was 47.04 ±7.78 (median 50, IQR 7.7), giving a mean (SD) change from baseline of 25.36 ± 8.46 (95% CI 22.82 to 27.90; p <0.001). Binary logistic regression was used to identify the independent factors predicting a favorable functional outcome of Bon-T treatment. It showed that neglect was independent predictive factor treatment failure (p=0.009, OR=3.2) while previous injection of BoNT-A was an independent predictive factors of treatment success (p=0.009, OR=0.3).

Conclusion: our study showed a good response to BoNT-A injection delivered in the management of chronic upper limb spasticity resulting from stroke or traumatic brain injury. It demonstrated its outcome in improving muscle tone, function and QoL. It also showed that the majority of patients achieved their goal as defined at the start of the treatment, mainly for patients who received previous injection of BoNT-A.