Comparative Neuromuscular Histopathology of Cricopharyngeal Achalasia Patients with and without Previous Botulinum Toxin Treatment

Botulinum toxin injection for the treatment of upper esophageal sphincter dysfunction

OBJECTIVES

We sought to review the dysphagia-related outcomes and quality of life in a series of patients with upper esophageal sphincter (UES) dysfunction treated with cricopharyngeal (CP) botulinum toxin (BTX) injection, and to identify patient characteristics or CP muscle histologic features that predict efficacy of BTX injection.

METHODS

A retrospective chart review was performed on patients with UES dysfunction who underwent CP BTX injection. Dysphagia-related quality-of-life questionnaires based on the Eating Assessment Tool (EAT-10) were mailed to patients.

RESULTS

Forty-nine patients (30 female, 19 male; average age, 59 +/- 16 years) with UES dysfunction have been treated at our institution with CP BTX injection since 2000. Seventeen of these patients also underwent CP myotomy. Injections of BTX were occasionally repeated after the treatment effect subsided, and the BTX dose varied widely (average, 39 +/- 19 units). Improvement in symptoms was noted by 65% of patients. The overall complication rate was minimal, although many patients complained of transient worsening of dysphagia after CP BTX injection. Biopsy specimens of the CP muscle were evaluated in the subset of patients with CP BTX injection who proceeded to myotomy, with results of neuropathic, myopathic, and mixed histologic subtypes. The EAT-10 scores demonstrated a general trend toward improved swallowing outcomes after CP BTX injection.

CONCLUSIONS

This study reviewed findings from the largest published series of BTX treatment of UES dysfunction and evaluated the efficacy, patient satisfaction, and complications of this procedure. Dysphagia-related quality-of-life outcomes appear to be improved after CP BTX injection.

Cervical esophageal perforation and cricopharyngeal dysfunction

Spontaneous perforation of the esophagus is an uncommon event; when it does occur, it usually affects the thoracic esophagus. We present a rare and fatal case of spontaneous perforation of the cervical esophagus in a 68-year-old woman. We believe this rupture was related to a proximal outlet obstruction secondary to cricopharyngeal muscle dysfunction.

A 78-year-old man with difficulty swallowing

CP bar is an uncommon but important cause of dysphagia in elderly people. A CP bar is often undetected during upper endoscopy and might be missed with barium radiography if adequate attention is not focused on the hypopharynx. In suspected cases, evaluation for alternative etiologies of dysphagia is important because the CP bar might be an incidental finding. Secondary causes of CP dysfunction resulting from underlying primary myopathic or neuropathic disorders should be considered before therapy. The effectiveness of dilation and surgical myotomy in alleviating dysphagia associated with CP bars has been reported in small series.

Muscle biopsy substantiates long-term MRI alterations one year after a single dose of botulinum toxin injected into the lateral gastrocnemius muscle of healthy volunteers

Despite numerous clinical and experimental studies on botulinum toxin type A (BoNT/A), long-term alterations of muscle texture and fine structure following BoNT/A treatment have thus far not been studied in normal human skeletal muscle. After obtaining institutional review board approval, we performed a prospective, placebo-controlled, double-blinded follow-up study on two healthy adults using magnetic resonance imaging (MRI) and muscle biopsy to visualize long-term alterations after a single BoNT/A injection into the lateral head of the gastrocnemius muscle. MRI disclosed a high-signal-intensity pattern in short tau inversion recovery sequences, and a reduction of the cross-sectional area in the BoNT/A-injected, but not in the saline-injected contralateral control muscle (at 6 to 9 months in volunteer A: 73%, in B: 62%; at 12 months in A: 88%, and in B: 78%). Enzyme histochemistry, 12 months after injection, confirmed neurogenic atrophy of muscle fibers only in the BoNT/A-injected muscle. Electron microscopy revealed additional degenerative changes at the neuromuscular junction. The data confirm that MRI is a suitable tool to monitor the long-term effect of BoNT/A on skeletal muscle. Neurogenic muscle atrophy following a single BoNT/A injection should be taken into consideration when repeated BoNT/A injections into the same muscles are proposed.