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Updated: Jun 24, 2026

Chronic Post-Ischemia Pain Model for Complex Regional Pain Syndrome Type-I in Rats
Published on: January 21, 2020
Sympathetic block with botulinum toxin to treat complex regional pain syndrome
Ian Carroll1, J David Clark, Sean Mackey
1Department of Anesthesiology, Stanford University School of Medicine, Stanford, CA 94304-1573, USA. irc39@pain.stanford.edu
Abstract:
Complex regional pain syndrome is a refractory pain condition with few tested therapies. We hypothesized that botulinum toxin A (BTA) would prolong analgesia after sympathetic blocks in patients with complex regional pain syndrome. We compared the duration of standard lumbar sympathetic block (LSB) with bupivacaine to LSB with bupivacaine and BTA in nine patients with refractory complex regional pain syndrome. Median time to analgesic failure was 71 (95% confidence interval, 12-253) days after LSB with BTA compared with fewer than 10 days (95% confidence interval, 0-12) after standard LSB (log-rank, p < 0.02). BTA profoundly prolonged the analgesia from sympathetic block in this preliminary study.
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