Depoets, diverticular tunneling stricturotomy. Esophageal atresia with tracheoesophageal fistula is the most common congenital foregut malformation. These defects require repair and anastomosis soon after birth, but are often complicated by postoperative stricture and anastomotic diverticula. Strictures are the most common complication of the procedure and are traditionally managed using balloon dilation or incisional therapy, however sometimes anastomotic diverticula arise despite adequate anastomotic lumen diameter and require open surgical revision. Given the growth of natural orifice transluminal endoscopic surgeries, procedures like per-oral endoscopic myotomy serve as templates for possible third space submucosal therapies and the management of anastomosis related diverticula. This case details an 8-year-old female with a history of type C EATF status post esophageal anastomosis at birth. Despite incisional therapy and balloon dilation to 15 mm, she experienced persistent symptoms and development of a significant proximal diverticulum. We propose the use of an endoscopic third space submucosal tunneling procedure to carry out stricturotomy of an anastomotic scar band and management of its associated diverticulum. Procedure per-oral endoscopic tunneling stricturotomy or dPOETS presents an augmented use of the POEM technique and provides a minimally invasive approach in an otherwise treatment unresponsive situation. The following case was carried out by a pediatric gastroenterologist and therapeutic endoscopist. Endoscopy showed proximal dilation to 35 mm in a left wall diverticulum extending 1 cm distal to the anastomotic scar band and an intraoperative esophagram showed an anastomosis measuring 18 mm in diameter by 4 mm in length with a scar band adjacent to the diverticulum. Notably though, on endoscopy no mucosal disruptions were appreciated. An endoflip procedure using a 322N catheter showed no narrowing at the anastomosis site and no repetitive intergrade contractions were seen consistent with dysmotility which is frequently seen in esophageal atresia. A mucosal bleb was then created approximately 3 cm proximal to the diverticulum using an endoscopic needle and a methylene blue saline solution. A hybrid T-type knife was then introduced for mucosotomy, hydrodissection, and submucosal tunneling. The methylene blue solution was injected to further distend the submucosal space. After undermining the mucosotomy edges, the endoscope with transparent cap was then introduced. This cycle of injection and electrocautery continued upon full introduction of the endoscope to begin tunneling towards the scar band. The endoscope was intermittently removed from the submucosal space to evaluate the progression of dissection relative to the scar band and diverticulum by assessing for submucosal elevation and methylene blue discoloration on the mucosal surface. Use of the methylene blue solution provided not only a means to distend the submucosal space but improved differentiation of submucosal connective tissue from smooth muscle, vasculature, and the anastomotic scar tissue which has a similar appearance to muscle fibers but with a less organized fiber orientation. As the clean dissection plane between the submucosa and the muscle layer approached the anastomotic scar band, the appearance of the tissue in this interface changed from easily dissectable healthy submucosal tissue to more opaque, sturdy scar tissue that, when cut with electrocautery, will char. This post-incisional appearance with electrocautery mirrors that of muscle, however, this post-anastomotic region bears no muscle tissue and is comprised solely of scar tissue. Notably, this transition correlated with the endoscopic distance to the luminal scar band. Dissection proceeded slowly through this region to avoid accidental mucosotomy given the lack of a clear dissection plane, and here you can see the tunnel and submucosal swelling extending distal to the anastomotic scar band. At several locations, the stricturotomy was full thickness measuring approximately 2 centimeters in diameter, as seen in this clip, where apparent mediastinal fat is visualized at 11 o'clock. However, the majority of the submucosal tunnel approximately and immediately distal to the anastomotic scar was walled with muscularis propria on its deep surface. At the conclusion of the submucosal dissection, the tunnel was 3 centimeters in length and extended approximately 5 millimeters distal to the scar band. In non-expection of the lumen, the scar band is largely obliterated at the level of the stricturotomy adjacent to the diverticulum, as illustrated in this before and after comparison, and notably, the submucosal remains elevated secondary to underlying submucosal saline cushion. The mucosotomy site was closed using 7 through-the-scope clips, and attention was paid to avert the mucosal edges upon clipping and closure of the submucosal space, as illustrated here. The procedure was completed without any notable intraoperative complications. The patient's postoperative course remained unremarkable. On post-op day 1, an esophagram showed no leak from the depo at site and improved contour of the esophageal diverticulum. She was discharged on post-op day 3 to complete a 7-day course of prophylactic antibiotics and slowly advanced her diet to reach full diet on post-op day 7. Two months post-operatively, her solid food dysphagia remains resolved. Historically, open surgical stricturoplasty, often with esophageal tapering, was the only available therapy for symptomatic anastomotic diverticular disease with appropriate lumen diameter. An alternative to our depo at approach may have been repeat endoscopic incisional therapy with deeper incisions that would extend to the base of the diverticulum, however, this was felt to carry a high risk for difficult-to-close luminal perforation. The depo at procedure offers a minimally invasive endoscopic approach. Notably, however, unlike other third space esophageal procedures like depome and zepome, this procedure is a stricturotomy rather than a myotomy. Additionally, unlike these procedures, there's a lack of a clear dissection plane as you approach the anastomotic scar band, as seen here, and frequent and generous submucosal injection directed towards the mucosal surface can aid in prevention of accidental mucosotomy. However, amidst anastomotic scar tissue, this becomes more challenging, as seen here. This image shows now excised scar band and the stricturotomy site. This case is valuable for several reasons, but notably it offers a novel use of endoscopic third space submucosal tunneling in the pediatric population. Although a similar procedure to depome and zepome, there's a lack of a clear dissection plane in the region of the anastomosis where anastomotic scar and submucosal tissue blend. This requires a slow, methodical approach to submucosal third space dissection. The depo at procedure details yet another application of endoscopic third space submucosal surgery.

esophageal atresia

tracheoesophageal fistula

diverticular tunneling stricturotomy

minimally invasive procedure

pediatric endoscopy