3 million abdominal laparoscopic (key-hole) procedures are undertaken each year. The use of laparoscopic techniques to reduce patient trauma, speed up operations and reduce healthcare costs is expected to increase. CO2 insufflation is currently used to visualise the surgical field and create a space to operate within the abdomen. CO2 insufflation raises abdominal pressure which can result in reduced heart and lung function, hypercapnia, hypoxaemia and post-operative pain, all of which can prolong a patient’s stay in hospital. CO2 losses occur due to the use of suction devices and leakage, and difficulties can be encountered in using electrosurgical and laser based cutting and sealing devices. There is also a requirement for additional and frequent organ retraction.

  Figure. Deployed auxetic cylinder expansion mechanism

This project is working with a team of surgeons and an NHS business development manager to devise novel mechanical expansion mechanisms for an innovative new device – the LaparOsphereTM - for space creation and organ retraction in laparoscopic surgery. The device is intended to provide improved access and visibility for the surgeon, eliminate patient side effects associated with CO2 insufflation, enable the use of suction without deflation, improve the use of thermal cutting systems, remove the need for multiple gas tight access ports, eliminate recurrent deflation caused by CO2 leaks, remove the requirement for medical grade CO2, and reduce the need for additional instruments.

The researchers have attended theatre to help measure surface pressures and retraction distances applied to organs during abdominal surgery. These measurements have provided key inputs into the design requirements of the space creation and organ retraction device. CAD, Finite Element Modelling (Figure), laser cutting and 3D printing are being used to design and produce viable expansion mechanisms for simulation and testing during the development process.