Effects of Repeated Injections of Higher Doses of Botulinum Toxin on Lower Limbs of Spastic Hemiplegic Patients on Functional and Biomechanical Parameters of Gait

Background and aims : This study assed the cumulative effect of 3 injection cycles of Botulinum neurotoxin (BONT) of increasing doses on functional gait capacity (temporospatial parameters of gait : 1st and 2nd domains-ICF). Secondary outcomes were to assess the effect on hyper-resistance (HR)(1st domain-ICF). Methods : 32 people with HR after chronic stroke underwent 3 BONT injection cycles with increasing total doses (400, 600 and 800 U of Xeomeen). Evaluation of walking capacity (Quantified gait analysis -QGA- and clinical evaluations : 6MWT, 10mWT, timed up the stairs, TUG) were performed before and 1 month after each injection cycle for a total of 6 evaluations. Results : on the activities domain of the ICF, RM-ANOVA showed improvements on the 6MWT (+27m after cycle 2, +43.8m after cycle 3), the 10mWT (-1.6s after cycle 2, -1.8s before cycle 3) and the time up and down the stairs (-13.7s after cycle 2, -14.8s after cycle 3) after the 2nd and 3rd cycle of injections, but not after the 1st one (p<0.05), the TUG test improved after the 2nd cycle of injections (-2.9s before cycle 3). Improvements were also found on some of the spatiotemporal parameters assessed by the QGA. On the body structure and functions domain, significant reduction of HR on specific muscle groups (plantar flexors knee extended and flexed : reduction of 2 scores at the MAS after 3 cycles, p