To assess the efficacy of endoscopic-guided botulinum toxin injection into the cricopharyngeus muscle and evaluate the duration of its effects.

A 3-year prospective study of 12 patients undergoing injection of botulinum toxin was conducted, with a telephone survey to assess dysphagia pre-operatively, and at 1, 3 and 6 months post-treatment, using the MD Anderson Dysphagia Inventory.

Median age was 66.2 years. Causes of cricopharyngeal dysphagia included idiopathic cricopharyngeal hypertrophy (67 per cent), previous cerebrovascular accident (17 per cent), cranial nerve palsy (8 per cent) and previous chemoradiotherapy to the neck (8 per cent). There were no complications. Two patients had repeat injections after six months. There was significant improvement in MD Anderson Dysphagia Inventory scores at one and three months versus pre-operative scores (73.1 ± 14.9 vs 46.9 ± 7.6, p = 0.0001, and 65.1 ± 11.5 vs 46.9 ± 7.6, p = 0.0001), but not at six months (51.0 ± 11.0 vs 46.9 ± 7.6, p = 0.14).

Endoscopic-guided injection of botulinum toxin into the cricopharyngeus muscle is a safe and effective method for treating cricopharyngeal muscle dysfunction, lasting up to six months.