Targeted high concentration botulinum toxin A injections in patients with Raynaud's phenomenon: a retrospective single-centre experience.

Raynaud's phenomenon is a vasospastic condition affecting hands and feet which may lead to rest pain, ischemic ulcers and gangrene. Botulinum toxin A has been shown to improve peripheral circulation and relieve vasospastic symptoms. Our aim was to assess our treatment outcomes following Botulinum toxin A injections in patients with Raynaud's phenomenon and to explore the importance of toxin concentration and injection sites. Retrospective chart review of patients with primary and secondary Raynaud's syndrome treated with Botulinum toxin A injections and a literature review was conducted. The toxin dose, injection sites, symptom relief, healing of ulcers and complications were assessed. A total of 30 treatment episodes over a 7½ year period were included. All patients had failed medical management. Botulinum toxin A injection was injected primarily in the vicinity of the palmar digital neurovascular bundle. The average total Botulinum toxin A dose injected was 156 U and the concentration was 50 U/ml. All patients reported an improvement in symptoms and healing of digital ulcers. One patient reported a temporary muscle weakness. Six patients had a single treatment episode with long term benefit. Systemic sclerosis patients had an average of 6-month interval between treatment episodes. Higher doses of Botulinum toxin A has been well tolerated with no long term adverse effects. Our study shows that targeted low volume higher concentration Botulinum toxin A injections are effective in treating Raynaud's phenomenon.