Design, development and evaluation of an inflatable retractor for atraumatic retraction in laparoscopic colectomy

Laparoscopic colectomy is the gold standard in the treatment of malignant tumours arising in the mucosa of the colon wall. The procedure is performed under general endotracheal anaesthesia and involves establishing a pneumoperitoneum with the patient in the Trendelenburg position. However this position can cause anaesthetic difficulties due to excess blood flow to the head and neck, increased pressure on the diaphragm and increased venous pressure. In the absence of steep head-down positioning, the bowels fall or "spill" into the operating field, obstructing the surgical space. The primary goal of this work is to design an atraumatic laparoscopic retractor to minimise the Trendelenburg position whilst effectively retracting the bowels from the operating field. This work details the design, evaluation and optimisation of a novel, hand held, inflatable, laparoscopic retractor, through physical experimentation, computer simulation, and pre-clinical animal investigation. The optimised design for the inflatable retractor performs in line with simulated expectations, and was successfully tested for safety and technical feasibility in vivo in a porcine model, where the bowels were effectively removed from the operating space whilst the model remained in the supine position. These initial results represent a promising approach for the mitigation of the Trendelenburg position, whilst effectively retracting the bowels during laparoscopic colectomy, using this atraumatic, inflatable retractor.