Pneumothorax complicating botulinum toxin injection in the body of a dilated oesophagus in achalasia

Peroral endoscopic myotomy (POEM) for achalasia

Achalasia is an uncommon disorder that results from the degeneration of ganglion cells of the myenteric plexus in the lower esophageal wall. It is manifested by a loss of peristalsis in the lower part of the esophagus and failure of the lower esophageal sphincter (LES) to relax. Peroral endoscopic myotomy (POEM) is a minimally invasive intervention that aims to treat achalasia. It is regarded as the endoscopic equivalent of Heller myotomy. POEM is a form of natural orifice transluminal endoscopic surgery that is completed by creating a submucosal tunnel in the lower part of esophagus to reach the inner circular muscle bundles of the LES to perform myotomy, while preserving the outer longitudinal muscle bundles. The result is decreased resting pressure of the LES, facilitating the passage of ingested material. POEM was initially introduced to treat achalasia by targeting the LES. POEM has expanded to include gastric POEM (G-POEM), myotomy of the pyloric sphincter to treat gastroparesis, and per rectal endoscopic myotomy to treat adult Hirschsprung's disease.

Complications of botulinum toxin injections for treatment of esophageal motility disorders†

In achalasia and spastic esophageal motility disorders, botulinum toxin (botox) injection is considered an effective and low-risk procedure for short-term symptom relief. It is mainly offered to medically high-risk patients. However, no analysis of risks of botox injections has been performed. To determine the incidence and risk factors of procedure-related complications after esophageal botox injections, we analyzed the records of all patients undergoing botox injection therapy for esophageal motility disorders at four university hospitals in Europe and North America between 2008 and 2014. Complications were assigned grades according to the Clavien-Dindo classification. In 386 patients, 661 botox treatments were performed. Main indications were achalasia (51%) and distal esophageal spasm (DES) (30%). In total, 52 (7.9%) mild complications (Clavien-Dindo grade I) were reported by 48 patients, the majority consisting of chest pain or heartburn (29 procedures) or epigastric pain (5 procedures). No ulceration, perforation, pneumothorax, or abscess were reported. One patient died after developing acute mediastinitis (Clavien-Dindo grade V) following injections in the body of the esophagus. In univariate logistic regression, younger age was associated with an increased risk of complications (OR 1.43, 95%CI 1.03-1.96). Treatment for DES, injections into the esophageal body, more injections per procedure, more previous treatments and larger amount of injected botulinum toxin were no risk factors for complications. Esophageal botox injection seems particularly appropriate for high-risk patients due to low complication rate. However, it should not be considered completely safe, as it is associated with rare side effects that cannot be predicted.

Esophageal perforation, inflammatory mediastinitis and pseudoaneurysm of the thoracic aorta as potential complications of botulinum toxin injection for achalasia

Primary achalasia is a motility disorder of the esophagus involving impaired relaxation of the esophageal sphincter and, in later stages, dilatation and aperistalsis of the tubular esophagus. Endoscopic botulinum toxin injection to the lower esophageal sphincter is an effective and safe option in the treatment algorithm of achalasia, particularly in high-surgical-risk patients. In the present case report, we describe a rare complication of esophageal perforation following botulinum injection, resulting in associated inflammatory mediastinitis and formation of a pseudoaneurysm in the descending aorta. To the authors' knowledge, this is the first report in the literature of this rare complication of endoscopic botulinum injection. A contributing factor might have been the use of an injecting device with a significantly longer adjustable needle. Endoscopists should remain clinically vigilant to the potential complications associated with this common procedure.