Long-lasting effect of a single botulinum toxin injection in the treatment of oropharyngeal dysphagia secondary to upper esophageal sphincter dysfunction: a pilot study.

Objective: To evaluate the efficacy of botulinum toxin (BTX-A) injection in the cricopharyngeus muscle in patients with neurological dysphagia caused by alteration in the upper esophageal sphincter (UES) opening and with preserved pharyngeal contraction.

Material And Methods: A prospective pilot study was undertaken in 10 patients (7 brain lesions and 3 cervical spinal cord injuries), with a minimum time-lapse of 6 months from neurological lesion to BTX-A injection. Dysfunction of the UES opening and the presence of pharyngeal contraction were diagnosed by videofluoroscopy (VDF) and esophageal manometry (EM). The BTX-A (100 U) injection was guided by endoscopy. Clinical, VDF, and EM follow-ups were carried out at 3 weeks, 3 and 6 months, and at 1 year post-injection.

Results: Prior to treatment, 6 patients were fed by nasogastric tube. VDF showed impairment of the UES opening, residue in pyriform sinuses, and aspiration in all cases. During follow-up, there was a decrease in the number of patients that had aspiration: 3 patients at one year. During swallowing, EM showed a mean UES relaxation of 90% (range: 74.5-100%), residual pressure 3.2 mmHg (range: 0-13 mmHg) and pharyngeal amplitude 52 mmHg (range: 25-80 mmHg). At follow-up, a significant improvement in UES relaxation (98% (89-100%)) and pharyngeal contraction (97 mmHg (35-165 mmHg)) was observed. At 3 months, 6 patients were eating exclusively by mouth.

Conclusions: One single injection of BTX-A in the UES has long-lasting effectiveness in patients with neurological dysphagia caused by alteration in the UES opening and with pharyngeal contraction. Nevertheless, a randomized control trial should be done to confirm these results and rule out the effect of potential spontaneous improvement of neurological injury.