Pain during botulinum toxin injections in spastic adults: Influence of patients’ clinical characteristics and of the procedure

Introduction/Background The evaluation of pain during botulinum toxin (BT) injections has never been conducted in adults. Our main objective was to quantified pain perceived by individuals with a stroke, during BT injections. A second objective was to analyze clinical and technical determinants of a painful procedure. Material and method Observational study on 46 persons (19 M/27 W, 60.5 ± 16 years) evaluated without analgesia during injections of BT-A performed by 2 experts (15 years of experience each), 6.5 years after a stroke. Pain was evaluated by numeric verbal scale (0–10) after each step. Pressure hypoesthesia was assessed by Semmes–Weinstein monofilaments. The existence of chronic pain was established from a long-term intake of antalgic drugs. Following are presented in median [25 and 75th percentiles]. Results A total of 1288 numerical verbal scale results were analyzed. The most painful time was stimulation (4 [2.6–5.3]; P P P P P P r  = 0.3, P  = 0.01) and the withdrawal ( r  = 0.4, P  = 0.009). The needle's brand also influenced pain during puncture ( P  = 0.01). Pain was not influenced by the dose or the volume injected, neither by the product used. Conclusion Botulinum Toxin injection is a very painful act which imposes a rigorous pain prevention. Suppressing the stimulation does not suppress pain. Patients at risk for pain should be identified, and the procedure adapted.