The Effects of Botulinum Toxin A on Pain in Ischemic Vasospasm.

PURPOSE: The purpose was to describe the impact of botulinum toxin A (BTX-A) administration in patients with ischemic vasospasm on the magnitude and timing of pain relief and subsequent effect on opioid use. The secondary purposes were to determine the role of photoplethysomgraph (PPG) testing on treatment decisions, effect on patient-reported outcomes, and additional procedures. METHODS: A retrospective analysis of patients who received BTX-A injections was performed. Botulinum toxin type A was injected subcutaneously in symptom-specific 2-level patterns. Pain, shortened version of the Disabilities of the Arm, Shoulder, and Hand (QuickDASH), and opioid use (quantified by median morphine equivalents) were recorded and the need for repeat injections or unplanned surgeries was assessed. RESULTS: All patients (n = 20 patients; 31 hands) had ischemic pain from vasospasm and failed multiple pharmacological options. Average follow-up was 10.5 months. All patients had abnormal PPG amplitude (mean, 6.43 mm) at room temperature and increased amplitude (mean, 19.55 mm) after immersion in warm water. All patients (n = 12) with a PPG amplitude increase of 4 mm or greater had clinical success. Eleven of 13 patients had a clinically relevant decrease in pain at 20 minutes after injection. Clinically significant pain relief was sustained for 3 months (visual analog scale decreased by a mean of 4). Median morphine equivalent usage view decreased from 82.5 to 0 after injection. Patient-reported disability (QuickDASH) improved from 49 before treatment to 29 and 26 at 6 weeks and 6 months after BTX-A injection, respectively. Three patients were retreated for recurrent symptoms. Four patients required unplanned secondary procedures. CONCLUSIONS: Botulinum toxin type A administration can result in rapid (within 20 minutes) and sustained pain relief for several months with a reduction in opioid prescriptions. Botulinum toxin type A administration also improved patient-reported disability for 6 months. Use of PPG testing to determine baseline perfusion deficit and capacity to improve after warm water immersion was helpful in consideration of BTX-A use. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.