The safety and efficacy of a new liver retractor for the performance of laparoscopic upper gastrointestinal surgery ?V a preclinical evaluation study

Philip Chiu, MD, Billy Leung, Stanley Sy, Cecilia Chan, Simon Wong, FRCSEd, Carmen Poon, PhD

Department of Surgery, CUHK Jockey Club Minimally Invasive Surgical Skills Center, The Chinese University of Hong Kong

This is a preclinical study to evaluation the safety and effectiveness of a new laparoscopic retractor for liver retraction. The aim is to achieve adequate exposure of the gastroesophageal junction (GEJ) during the performance of laparoscopic upper gastrointestinal surgery.

This study consisted of preclinical experiments in ex-vivo and in-vivo models. In ex-vivo experiments, the physical properties of the new retractor were compared to conventional Nathanson retractor. These included testing of the friction force between the retractor surface and standardized porcine liver. 31 standardized porcine liver samples were prepared, while the liver samples were placed onto the retractor which was fixed on a platform. The platform would then be tilted and the force required to keep the liver in position was measured. In in-vivo experiment, two porcine models and three cadaveric models were recruited. In the non-survival animal experiments, the exposure and durability of exposure of the GEJ was tested with the performance of laparoscopic Nissen fundoplication. The new articulating retractor was introduced through right lower abdominal port. The time to achieve good exposure and the time to complete the fundoplication was recorded. In the cadaveric model, we tested the effect of GE junction exposure by introducing the retractor through placing the abdominal port at different positions.

When compared to Nathanson retractor, the new laparoscopic retractor required less force to maintain the position of liver in ex-vivo study (Fig 1). The coefficient of fraction was found to be significantly higher for the new retractor when compared to Nathanson retractor (Fig 2). We performed laparoscopic Nissen fundoplication in two 30 kg pigs in a non-survival study. The time for effective exposure of GEJ was 2 minutes for first and 1 minute for second pig, while operative time for laparoscopic Nissen Fundoplication was 27 minutes for first and 21 minutes for second pig. There was no readjustment of the retractor during the procedure. In three cadaveric models, the optimal position for introduction of the new liver retractor was found to be at right upper quadrant of the abdomen.

The new articulating laparoscopic liver retractor can achieve excellent exposure of the GEJ to enhance the performance of upper GI surgery. This preclinical data support the conduction of human clinical study using the new designed liver retractor for performance of laparoscopic upper gastrointestinal surgery

Session: Poster Presentation

Program Number: P386

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