Novel endoscopic application of a new flexible-fiber CO₂ laser for esophageal mucosal ablation in a porcine model

Background and study aims: The CO₂ laser is a surgical tool that is widely used because of its predictable penetration depth and minimal collateral damage due to efficient absorption of CO₂ laser energy by tissue water. Until recently, endoscopic use was limited by lack of an efficient, flexible delivery system. The aim of the current study was to evaluate the performance, efficacy, and safety of a novel, photonic band-gap CO₂ laser configured for esophageal mucosal ablation. Materials and methods: This was an endoscopic experimental study in a porcine survival model. Initial evaluation was done on ex vivo tissue followed by endoscopic studies at 7-, 10-, 15-, and 20-W power and at 0-, 1-, 2-, 5-, and 10-mm distances, using continuous and pulsed currents, to determine optimal performance settings. In an IACUC-approved protocol, six pigs underwent circumferential ablation of the distal 6 cm of the esophagus at 10W continuous current. The animals were monitored for 2 or 4 weeks to evaluate delayed effects. Prior to euthanasia, the proximal esophagus was ablated to evaluate the homogeneity of ablation and depth of injury immediately after single and repeat ablation. Results: The animals resumed normal diets within 24 hours and experienced no dysphagia or weight loss. Pathology at 2 and 4 weeks revealed complete re-epithelialization with minimal histologic injury. A single application of the laser produced complete transepithelial ablation of a mean of 83.3% of the surface area (range 55%-100%); depth of injury was to the muscularis mucosa in five pigs and to the superficial submucosa in one pig. With ablation, sloughing, and re-ablation, a mean of 95% transepithelial ablation was achieved (range 80% -100%) with similar depth of injury. Conclusions: Using a novel, flexible CO₂ laser, homogeneous ablation was achieved with predictable penetration and minimal deep tissue injury. These results warrant further evaluation of the laser in Barrett's esophagus, as it may overcome the limitations of current technologies including perforation, stricture, and inhomogeneity.