Injection of botulinum toxin A for the treatment of dysfunction of the upper esophageal sphincter

Abstract

Objective

The objective was to evaluate changes in swallow safety and dietary status after the transcutaneous injection of botulinum toxin A into the upper esophageal sphincter in a series of outpatients with dysphagia.

Study design

This was an experimental, prospective, nonrandomized study.

Methods

Patients who were at risk for aspiration and who had an unsuccessful trial of swallowing therapy were admitted to the study. All patients showed significant pooling of fluids in the postcricoid region. All patients were treated in the office; none had previous esophageal dilatation. The upper border of the cricoid cartilage was identified using standard electromyogram procedures and 100 U of botulinum toxin (Botox A) were injected. Outcomes were assessed using the penetration-aspiration scale, patients' short-term and long-term subjective impressions of their ability to swallow, and change in dietary status.

Results

Thirteen patients underwent an instrumental evaluation of swallowing function at approximately 6 months after treatment to corroborate the self-reported changes in swallowing. Of the 13 patients, 12 showed an overall improvement in their ability to take an oral diet safely as evidenced by the penetration-aspiration scale. Of the 12 patients who were on a non-oral or nearly non-oral diet, 9 resumed a normal oral diet. The remaining 3 were on an oral diet supplemented by percutaneous endoscopic gastrostomy feeding. One patient remained on a non-oral diet.

Conclusions

Injection of Botox A in the office with no additional treatments resulted in a long-term increase in swallow safety, a reduction of penetration and/or aspiration, and a reduced need for non-oral feeding. Injection of Botox A in the office should be considered when there is failure of the cricopharyngeus muscle to relax after the swallow, significant pooling in the cricopharyngeal region, and a risk for penetration and aspiration.

Introduction

Before 1994, the primary treatment of primary upper esophageal sphincter (UES) dysfunction included surgical myotomy, dilatation, or neurectomy of the pharyngeal plexus [1], [2], [3]. Since 1994, botulinum toxin A (BTX A) has been used as an alternative to surgery for the treatment of UES dysfunction. The injection of BTX A does not enhance UES function, but rather reduces its tonic and active contraction; thus, only patients with absolute or relative hypertonicity of the UES may benefit from a BTX A injection.

When injected into a muscle, BTX A causes flaccidity by inhibiting the release of acetylcholine from the nerve endings. Disorders characterized by excessive or inappropriate muscle contraction or spasmodic muscle activity, such as spasmodic dysphonia and oral mandibular dystonia, show a reduction in the spasmodic behavior when the affected musculature is injected with BTX A. Treatment outcome is usually measured clinically in terms of improved function.

Botulinum toxin A exists as 8 serotypes, although only the A type is routinely used in human movement disorders of the head and neck. Because of its effectiveness, relative ease of administration, and safety record, the injection of BTX A has gained acceptance for the treatment of movement disorders of the upper aerodigestive tract and the head and neck. Since its first reported human use in 1980, for the treatment of strabismus [4], BTX A has been used to treat a variety of disorders that include blepharospasm, hemifacial spasm, laryngeal spasm, and temporomandibular joint dysfunction among others [5].

Various reports have described the use of BTX A for the treatment of cricopharyngeal dysfunction [6], [7], [8], [9], [10], [11], [12], [13]. Investigators have reported on the injection of BTX A under direct intraoperative observation or under transendoscopic visualization to improve swallowing function or to improve tracheoesophageal speech production in laryngectomy patients who present with dysfunction of the upper esophageal sphincter.

Table 1 summarizes previously reported results using BTX A for the treatment of UES dysfunction [6], [7], [8], [9], [10], [11], [12], [13]. In all of the previous studies, BTX A was injected under direct visualization during transcervical surgery or under endoscopic visualization. Favorable results were reported in some cases; in others, no follow-up or very short-term follow-up or results were reported. However, it may be argued that both the transendoscopic and the trancervical procedures reported in Table 1, or even the general anesthesia used in these cases, may contribute to the reduction of tone of the UES. Moreover, no specific short-term or long-term outcome measures were used to assess the previously reported results.

The purpose of the present study was to evaluate the effect of an unsedated transcutaneous injection of BTX A in the office in patients with dysphagia associated with UES dysfunction and who have not responded to conventional swallowing therapy.