Mo1628 A New Potential Method Per Anus Endoscopic Myotomy for Treatment of Internal Anal Sphincter Achalasia

Abstract

A New Potential Method Per Anus Endoscopic Myotomy for Treatment of Internal Anal Sphincter Achalasia Lei Wang*, Qiang Cai, Chaoqiang Fan, Wei Ren, Jin Yu digestive diseases, xinqiao hospital chongqing, Chongqing, China; medicine, division of digestive diseases, Alanta, GA Background: Internal anal sphincter achalasia (IASA) is a condition with presentation similar to Hirschsprung’s disease (HD), but with the presence of ganglion cells on rectal suction biopsy (RSB). The diagnosis is made on anorectal manometry (ARM) by the absence of the rectosphincteric reflex on rectal balloon inflation. Internal sphincter myectomy (ISM) is the treatment of choice for patients with IASA. Per oral endoscopic myotomy(POEM) is new method for treatment of esophageal achalasia in recent years. By this method, the muscle layer of the GI wall can be incised safely in the submucosal tunnel. Because the pathogenesis of IASA is similar to the esophageal achalasia, we hypothesized that the per anal endoscopic myotomy(PAEM) can be used to treat IASA and evaluated the efficacy and safety of PAEM in animal model. Materials And Methods: Five 8-week-old pigs were used for this experiment. Under ketamine sedation, baseline internal anal sphincter (IAS) pressures were recorded and the pigs underwent normal sigmoidoscopy. The mucosal incision was made at approximately 1cm orally to the proximal margin of the Z line to creat mucosal entrance to the submucosal space. A submucosal tunnel was created from approximately 1cm to 10cm above the Z line of anus with triangle knife in the posterior wall. Then the scope was introduced into the submucosal tunnel and advanced toward the now visible fibers of the IASA. The circular muscle layer was incised 7cm to 9cm length by triangle knife in the submucosal tunnel. The incision was closed with the clips. Manometry was repeated on day 5 after the procedure. The two animals were euthanized on day 7 and the other three animals were euthanized on day 14. Results: All the five pigs were observed for 1 week and the three pigs were observed 2 weeks. All the pigs appeared to do well, with no evidence of fever or loss of appetite during observing time. The anal maximum resting pressure (AMRP) significantly decreased from an average of 44.5 cmH2O to an average of 14.3 cmH2O after the myotomy. There were significant differences between before and post PAEM with respect to histologic evaluation of inflammation and muscle defection. The circular layer appeared to be cleanly cut with no significant adhesions. Necropsy revealed no evidence of perianal inflammation. Conclusion: Per anal endoscopic myotomy is feasible, safe, and effective in the short term. It has the potential for being useful in patients with achalasia.