In actual fact, achalasia affects the entire esophagus, which is paralyzed (chalasia=relaxation), much too long, and subject to muscular hypertrophy; esophageal folds are therefore lacking, as is correctly shown in the figure accompanying the article. Impedance manometry confirms the fact that the entire esophagus is affected: no spasmolytic drugs will help, the esophagus is passively closed, which is shown by the elastance pressure volume curve.
The esophagus does not have a lower sphincter but a centimeter-long muscular elastic closure segment consisting of two spiral shaped tubes that are inconspicuously embedded in the muscle wall (and act as an extension splint/brace. The muscle fibers in the esophagus are arranged in an elongated spiral in an oval shape and transport food.
If a botulinum toxin injection is carried out the endoscope penetrates into this long segment and unintentionally distends it. Botox paralyzes only skeletal muscles. In human beings, smooth muscles in a spiral arrangement are found in the distal esophagus (2).
Myotomy always splits only the easily detachable, very thick outer layer of the elastic esophageal closure segment and not the thinner, inner layer that has grown together with the epithelium. The inner tube therefore remains paralyzed but does not act as an obstruction any longer.
The studies do not provide any new treatment for achalasia, merely for reflux esophagitis—by tightening the slack closure mechanism. The existing comprehensive literature does not include the underlying etiology that explains all these disorders.
Footnotes
Conflict of interest statement
The author declares that no conflict of interest exists.
The authors of the article have chosen not to publish a reply.
References
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