Submucosal endoscopic esophageal myotomy: a novel experimental approach for the treatment of achalasia.
OBJECTIVE
The most permanent method of treating achalasia is a surgical myotomy. Because of the requirement for a mucosal incision and the risk of perforation, this procedure has not generally been approached endoscopically. We hypothesized that we could perform a safe and robust myotomy by working in the submucosal space, accessed from the esophageal lumen.


METHODS
Four pigs were used for this experiment. Baseline lower esophageal sphincter (LES) pressures were recorded and the pigs underwent upper endoscopy using a standard endoscope. A submucosal saline lift was created approximately 5 cm above the LES and a small nick was made in the mucosa in order to facilitate the introduction of a dilating balloon. After dilation, the scope was introduced over the balloon into the submucosal space and advanced toward the now visible fibers of the LES. The circular layer of muscle was then cleanly incised using an electrocautery knife in a distal-to-proximal fashion, without complications. The scope was then withdrawn back into the lumen and the mucosal defect was closed with endoscopically applied clips. The entire procedure took less than 15 minutes. Manometry was repeated on day 5 after the procedure and the animals were euthanized on day 7.


RESULTS
LES pressures fell significantly from an average of 16.4 mm Hg to an average of 6.7 mm Hg after the myotomy. The necropsy examinations revealed no evidence of mediastinitis or peritonitis.


CONCLUSIONS
Endoscopic submucosal esophageal myotomy is feasible, safe, and effective in the short term. It has the potential for being useful in patients with achalasia. The submucosal space is a novel and potentially important field of operation for endoscopic procedures.
Pasricha
P J
PJ
Divison of Gastroenterology, University of Texas Medical Branch at Galveston, Galveston, Texas 77555-0764, USA. jpasrich@utmb.edu
Hawari
R
R
Ahmed
I
I
Chen
J
J
Cotton
P B
PB
Hawes
R H
RH
Kalloo
A N
AN
Kantsevoy
S V
SV
Gostout
C J
CJ
D000818:Animals; D013505:Digestive System Surgical Procedures / Q000379:methods*; D004931:Esophageal Achalasia / Q000601:surgery*; D049630:Esophageal Sphincter, Lower; D004945:Esophagoscopy; D004947:Esophagus / Q000601:surgery; D005240:Feasibility Studies; D008365:Manometry; D023421:Models, Animal; D009092:Mucous Membrane / Q000601:surgery; D009132:Muscles / Q000601:surgery; D013552:Swine