Transtracheal thoracic natural orifice transluminal endoscopic surgery (NOTES) in a swine model.

Abstract

Natural orifice transluminal endoscopic surgery (NOTES) has the potential to be the final frontier in minimally invasive procedures in thoracic surgery. In order for thoracic pleural NOTES to 1 day be ready for clinical trials, each step of the procedure must be independently evaluated for both safety and efficacy. The aim of this study was to evaluate the trachea as a portal of entry for thoracic NOTES. Eight 40-kg swine underwent right thoracic pleuroscopy in a survival model. In order to avoid inadvertent injury to the superior vena cava, endobronchial ultrasound was employed to select the location of airway incision. A 7-mm linear incision was then performed at the chosen location using an endoscopic electrocautery needle knife through a therapeutic flexible videobronchoscope. The mediastinal fat and parietal pleura were then dissected with electrocautery, and complete right pleuroscopy was performed. The tracheal and mediastinal portal of entry were then sealed with 1-2 cc of fibrin sealant. The pigs were kept alive for 21 days postoperatively. Postmortem diagnostic bronchoscopy was performed to assess tracheal healing. All tracheal specimens underwent histologic examination for healing and signs of mediastinal infection. Thoracic NOTES procedures on all eight pigs were successful. There were no intraoperative complications except for one minor bleeding episode within the mediastinal dissection site which stopped spontaneously. Two pigs died from severe laryngospasm in the early postoperative period. Six pigs survived for 21 days post-procedure and experienced uneventful postoperative courses. Postmortem examination demonstrated complete tracheal healing with appropriate scarring in all pigs. The trachea appears to be a safe port of entry for thoracic NOTES procedures in a swine model. Smaller tracheal incisions followed by balloon dilatation are associated with less postoperative morbidity and mortality. Tracheal incisions sealed with fibrin sealant healed rapidly and without signs of mediastinal infection. This procedure represents a work in progress and is not yet ready for human trials.