Mesenteric neovascularization during spring-mediated intestinal lengthening.

BACKGROUND: Short gut syndrome, a condition characterized by inadequate absorption of nutrients owing to decreased bowel length, has minimal avenues for treatment. We have proposed spring-mediated distraction enterogenesis to lengthen bowel in porcine jejunum as a treatment for short gut. We aim to evaluate the extent of mesenteric neovascularization in segments of lengthened bowel via spring-mediated enterogenesis. METHODS: Female juvenile Yucatan pigs underwent laparotomy and insertion of gelatin-encapsulated compressed nitinol springs, held in place with plication sutures, into the jejunum. At surgery and sacrifice, macroscopic mesenteric blood vessels were counted between the plication sites. Histologic samples of the mesentery were obtained to evaluate microscopic vasculature. RESULTS: A statistically significant increase in macroscopic mesenteric blood vessels was seen after intestinal lengthening (before: 1.9 ±â€¯0.7 vessels, after: 4.7 ±â€¯1.2 vessels, p = 0.001). A statistical significance is also seen in the density of arterioles (control: 3.0 ±â€¯3.0 vessels/mm, spring: 7.0 ±â€¯9.0 vessels/mm, p = 0.01) and venules (control: 4.0 ±â€¯3.0 vessels/mm, spring: 8.0 ±â€¯8.0 vessels/mm, p = 0.003). CONCLUSION: Intestinal segments lengthened by intraluminal springs demonstrated total greater number of macroscopic vessels and microscopic blood vessels per length of mesentery as compared to control. This suggests local changes within the mesentery to recruit blood supply to growing intestine. LEVEL OF EVIDENCE: N/A TYPE OF STUDY: Treatment study.

Mechanical lengthening of porcine small intestine with decreased forces.

INTRODUCTION: short bowel syndrome is marked by inadequate intestinal surface area to absorb nutrients. Current treatments are focused on medical management and surgical reconfiguration of the dilated intestine. We propose the use of spring-mediated distraction enterogenesis as a novel intervention to increase intestinal length. Given our previous success lengthening intestinal segments using springs with spring constant ~7 N/m that exerts 0.46 N or higher, we sought to determine the minimal force needed to lengthen porcine small intestinal segments, and to explore effects on intestine over time. METHODS: Juvenile Yucatan pigs underwent laparotomy with enterotomy to introduce nitinol springs intraluminally (n = 21 springs). Bowel segments (control, spring-distracted) were retrieved on post-operative day (POD) 7 and 14, and lengths measured. Thickness of cross-sectional intestinal layers were measured using H&E, and submucosal collagen fiber orientation measured using trichrome stained sections. RESULTS: all pigs survived to POD7 and 14. Spring constants of at least 2 N/m exerting a minimum force of 0.10 N significantly lengthened intestinal segments (p <0.0001). The stronger the spring force, the greater the induced thickness of various intestinal layers at POD7 and 14. Collagen fiber orientation was also more disordered because of stronger springs. CONCLUSION: a spring constant of approximately 2 N/m exerting 0.10 N and greater significantly lengthens intestinal segments and stimulates intestinal structural changes at POD7 and 14. This suggests a decreased force is capable of inducing spring-mediated distraction enterogenesis.

Treating children with achalasia using per-oral endoscopic myotomy (POEM): Twenty-one cases in review.

BACKGROUND: Per-oral endoscopic myotomy (POEM), a modern treatment for achalasia, has only recently emerged as an option for pediatric patients. Here we describe and characterize the success of POEM in children with achalasia. METHODS: A single-institution prospective cohort study was performed of patients <18 years old who underwent POEM from 2014 to 2019. Main outcomes were success at one year (Eckardt ≤3), procedure duration, complications, reintervention. RESULTS: The median age of patients (n = 21) was 13 years (range 2-17). Median procedure duration was 92 min (range 52-259) with case duration plateau of 87.4 min and learning rate of 15.5 cases. Intraoperative complications included capnoperitoneum requiring needle decompression and mucosotomy requiring additional clips. One patient experienced chest pain with small capnoperitoneum seen on chest radiography, and three patients had extraluminal carbon dioxide found incidentally on routine radiography. All were managed with observation. Pre- versus 1-month postprocedure Eckardt scores were significantly improved (7 ±â€¯2 versus 1 ±â€¯2, p < 0.0001, and median ±â€¯SD) with 100% symptomatic relief at one year. To achieve this, 13 patients required further dilation(s), one required laparoscopic Heller myotomy, and two required repeat POEM. CONCLUSIONS: POEM is a viable and safe treatment for pediatric patients with achalasia. We demonstrate improvement in symptoms and procedure proficiency with minimal intra- and postoperative complications. TYPE OF STUDY: Prospective cohort study. LEVEL OF EVIDENCE: Level II.