Novel endoscopic management of gastroenterological anastomosis leakage by injecting gel-forming solutions: an experimental animal study

Abstract

Background: Anastomotic leakage (AL) after gastrointestinal surgery remains a challenging complication that requires surgical or non-surgical treatment. Although various therapeutic endoscopic techniques are available, no definitive interventions exist. We developed a therapeutic endoscopic submucosal injection method using novel gel-forming mixed solutions to close AL and evaluated the elasticity of the developed hydrogel. The safety and efficacy of the injection method were explored in porcine AL models.

Methods: We developed a novel gel-forming solution, and the formed gel lasted approximately one week within the gastrointestinal wall. An indentation test evaluated the elasticity of the novel hydrogel. After the confirmation of AL on porcine anterior gastric walls, sodium alginate was endoscopically injected into the submucosal layer around the leakage site circularly, followed by a calcium lactate/chitosan-based solution. After that, the outcomes data were collected, and histopathological effectiveness was evaluated.

Results: The increased sodium alginate elasticity with the addition of calcium lactate/chitosan-based solution facilitated long-lasting gel formation. Four pigs with AL underwent this intervention consecutively. Each endoscopic injection was completed in less than 5 min. No significant complications were observed for 3 weeks after the intervention. All AL sites were macroscopically healed. Histopathologic findings at 3 weeks showed that the wall defect was filled with collagen fibers that had grown around the site of the muscle layer tear. No tissue necrosis was observed.

Conclusion: This preclinical study demonstrated that the therapeutic injection method for gastroenterological AL using gel-forming solutions could be an alternative endoscopic treatment, especially in patients with severe conditions or comorbidities. The optimal target of this treatment is small size and early AL without poor blood flow or intense hypertrophic scar lesions.

Keywords: Chitosan; Endoscopic technique; Fistula; Hydrogel; Non-surgical management; Therapeutic endoscopy.