Introduction Currently colonic lesions unsuitable for endoscopic resection are treated by segmental resection. However local full thickness excision alone may be sufficient and potentially would reduce immediate complications and subsequent morbidity. A novel technique is presented describing this.

Methods With storyboard planning, the full thickness laparo-endoscopic excision (FLEX) concept evolved to entail initial endoscopic outlining of the lesion to be excised by circumferential argon plasma coagulation 1 cm from the lesion edge under synchronous laparoscopic control. Thereafter three separate brace bars are laparoscopically placed, transmurally around the lesion, from the intraperitoneal aspect 1 cm outside of the area circumscribed endoscopically and under direct endoscopic vision, with each one then being cinched to achieve inversion of the segment to be excised. The serosal aspect of the inversion site is oversewn laparoscopically in two layers to ensure security. A second endoscope is then passed transanally into the sigmoid colon to assist with intraluminal tissue traction. A full thickness excision of the hemi-circumferential fold that has been inverted into the bowel is then performed endoscopically.

The feasibility and safety of this innovative approach was determined in a series of seven large White Landrace-Cross pigs with a sigmoid colonic pseudopolyp (created by endoscopic ink injection) as the target lesion. The first three procedures were used to standardise the technical components and steps and allow immediate assessment of technique competence by post-procedural laparotomy. The next four pigs underwent the same procedure with a post-procedural survival study, concluding with postmortem at 7–10 days to allow peritoneal and resection site scrutiny and bursting pressure assessment.

Results The procedure was technically successful in every case without inducing inadvertent injury or bleeding. Median resected specimen diameter was 2.5 cm (range 2–3). Acute series post mortem examinations confirmed secure apposition without compromise of luminal diameter while all four survival animals thrived post-operatively. Late forensic laparotomy revealed neither sepsis nor complicated healing nor intraperitoneal adhesion formation. Lumen diameter was normal while bursting pressures of the colonic excision site were a median of 245 mm Hg (range 240–260).

Conclusion This novel combined approach proved an effective and safe means of achieving full thickness resection of a site in the colon in this porcine series. While some components could be formatted in future for single port or natural orifice endoscopic working, the FLEX procedure is suitable for evaluation in clinical practice for selected patients.