Which of the following mode of treatment for achalasia is associated with high rate of recurrence?

Botulinum toxin, injected into the lower esophageal sphincter under endoscopic guidance, inhibits acetylcholine release from nerve endings and improves dysphagia in about 66% of cases of achalasia for at least 6 months. This technique is useful only for temporary relief of symptoms, thus associated with high rate of recurrence. Ref: Harrison's Internal Medicine, 18th Edition, Chapter 292