Biomagnetic retraction for endoscopic surgery

In open surgery the surgeon may use his hands or a range of large instruments to retract organs. In Minimal Access Surgery (MAS, popularly known as 'keyhole' surgery) it is not possible to do this. Special retractors have been developed for MAS, but these do not work very effectively and may sometimes traumatise tissues and organs.This proposal is based on a previous EPSRC pilot grant, the results of which confirmed the feasibility of rendering small areas of tissue ferromagnetic: these localised ferromagnetic regions can then be retracted and manipulated using magnetic probes during MAS and recent variations on this surgical approach: natural office surgery (NOS) and single port laparoscopic surgery (SPLS). The proposed research involves the development of - a novel system for the injection of ferromagnetic media to allow magnetic retraction of bowel during MAS, SPLS and NOS. The ferromagnetic media is injected directly into the bowel and is excreted normally after the operation;- a new method for surface ferromagnetisation of tissues by developing novel ferromagnetic plastic films which adhere to the wet surfaces of the internal organs: these materials (known as muco-adhesive polymers) will be configured primarily for pull retraction by magnetic probes but with other biomedical applications, e.g., surface marking of localised small lesions discovered during examinations with an endoscope; - design and development of novel technologies for magnetic grasping, as distinct from pull retraction, in conjunction with an adjustable magnetic force system which can be deployed either on the inner surface of the abdominal wall or outside the body. Multiple grasping devices, computer controlled from outside the body, can be used to handle the bowel as gently as possible to reduce the risk of injuryThese three strands constitute closely related components of an entirely novel system for magnetic retraction for the various MAS approaches. In the development of each strand extensive use will be made of a computer analysis technique known as finite element modeling, as well as experimentation in models of the relevant anatomy.The project requires the involvement of several different scientific disciplines: chemistry to create the polymer, physics to identify the desired characteristics of the ferromagnetic materials, engineering to create workable products from the scientific knowledge and surgery to direct the application of the entire enterprise.

Development of mucoadhesive films for biomagentic retraction based on PAA-PVA blends. Magentisation acheived through use of FeO nanoparticles both commercial and in-house prepared. Further to this exploration of hybrid gel systems show greater promise for natural orifice surgery (IAA EPSRC/ St Andrews Award)