Background and aims: Third-space endoscopy is a novel, safe, and effective method for treating different gastrointestinal conditions. However, several failed endoscopic procedures are attributed to incomplete myotomy. Lighting devices are used to prevent organic injuries. We aimed to investigate the feasibility of using a hand-made LED-probe (LP) in third-space procedures.Patients and Methods: This prospective study was conducted in a tertiary-care center in Mexico between December 2016 and January 2019. We included peroral endoscopic myotomy (POEM) and gastric peroral endoscopic myotomy(G-POEM) procedures. Pseudoachalasia, peptic ulcer, normal gastric emptying scintigraphy (GES) and prepyloric tumors were excluded. LP was used to guide or confirm procedures. Clinical and procedural characteristics were recorded and analyzed.Results: Seventy third-space procedures were included (42POEM,28G-POEM), with an average patient age of 46.7±14.3 and 43.7±10.1 years, respectively. For the POEM and G-POEM groups, respectively, 18/42(42.9%) and 13/28(46.7%) patients were males; median procedure times were 50 (interquartile range[IQR]: 38-71) and 60(IQR: 48-77) min, median LP placement times were 5(IQR: 4-6) and 6(IQR: 5-7) min, mild adverse events occurred in 4(9.4%) and 4(14.2%) of cases, and clinical success at 6 months occurred in 100% and 85.7% of cases. Integrated relaxation pressure (IRP) improved from 27.3±10.8 to 9.5±4.1 mmHg (p<0.001); retention percentage at 4 hours also improved. LP was successfully placed and adequate myotomy confirmed including 14.2% and 17.8% of POEM and G-POEM difficult patients. Conclusions: Using an LP is promising and allows guiding during third-space procedures either for submucosal tunnel creation or myotomy confirmation, with excellent safety and efficacy in clinical practice.

Background and aims: Third-space endoscopy is a novel, safe, and effective method for treating different gastrointestinal conditions. However, several failed endoscopic procedures are attributed to incomplete myotomy. Lighting devices are used to prevent organic injuries. We aimed to investigate the feasibility of using a hand-made LED-probe (LP) in third-space procedures. Patients and Methods: This prospective study was conducted in a tertiary-care center in Mexico between December 2016 and January 2019. We included peroral endoscopic myotomy (POEM) and gastric peroral endoscopic myotomy(G-POEM) procedures. Pseudoachalasia, peptic ulcer, normal gastric emptying scintigraphy (GES) and prepyloric tumors were excluded. LP was used to guide or confirm procedures. Clinical and procedural characteristics were recorded and analyzed. Results: Seventy third-space procedures were included (42POEM,28G-POEM), with an average patient age of 46.7±14.3 and 43.7±10.1 years, respectively. For the POEM and G-POEM groups, respectively, 18/42(42.9%) and 13/28(46.7%) patients were males, median procedure times were 50 (interquartile range[IQR]: 38-71) and 60(IQR: 48-77) min, median LP placement times were 5(IQR: 4-6) and 6(IQR: 5-7) min, mild adverse events occurred in 4(9.4%) and 4(14.2%) of cases, and clinical success at 6 months occurred in 100% and 85.7% of cases. Integrated relaxation pressure (IRP) improved from 27.3±10.8 to 9.5±4.1 mmHg (p<0.001); retention percentage at 4 hours also improved. LP was successfully placed and confirmed adequate myotomy including 14.2% and 17.8% of POEM and G-POEM difficult patients. Conclusions: Using an LP is promising and allows guiding during third-space procedures either for submucosal tunnel creation or myotomy confirmation, with excellent safety and efficacy in clinical practice.