Of 76 elderly patients with HFS treated with botulinum toxin, 84.2% were spasm-free at last follow-up (median 44.5 months) and 15.8% continued to have some spasms. Age (p=0.38, CI [0.38, 1.07], OR = 0.94), sex (p=0.59, CI [0.17, 2.89], OR = 0.68), side (p=0.15, CI [0.06, 1.54], OR = 0.31), pre-operative symptom duration (p=0.7, CI [0.5, 1.6], OR = 0.89), and number of pre-operative botulinum toxin treatments (p=0.3, CI [0.149, 1.81], OR = 0.52) were not predictors of spasm-freedom after surgical decompression.