Sympathetic block with botulinum toxin to treat complex regional pain syndrome

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.

Conflict of interest statement

Potential conflict of interest: The authors report filing a patent for the use of botulinum toxins in sympathetic block.

Figures

Fig 1

Duration of analgesia. Analgesic duration of lumbar sympathetic block is extended by botulinum toxin type A (BTA). Black line represents bupivacaine; red line represents bupivacaine plus BTA. Median time to analgesic failure was 69 days after lumbar sympathetic block with BTA compared with fewer than 8 days among those receiving local anesthetic alone. Log-rank, p < 0.02.

Fig 2

Change in visual analog pain score (VAS) over time. Botulinum toxin type A (BTA) reduces VAS sores of pain intensity over protracted time periods in responders. Assignment to the BTA-enhanced lumbar sympathetic block was associated with a mean decrease in VAS of 1.6 points (95% confidence interval, 1.2–2.0; p < 0.0001). Patients appear to be BTA responders or nonresponders. Despite refractory long-standing pain, Patients 1, 2, and 7 experienced long-term significant reduction in pain. Note time scales for each patient and each injection differ because each patient recorded pain until they perceived they had returned to baseline. All injections occurred on day 7 after a 1-week “run-in” period. Black lines represent bupivacaine; red lines represent bupivacaine plus BTA. Patients 1 (A), 2 (B), 4 (C), 5 (D), 6 (E), 7 (F), 8 (G), and 9 (H).