[Note: Talk advertised as 'Medical Electronics']
Professor Tony Pipe, Deputy Director of the Bristol Robotics Laboratory, gave a talk on their work in the field of Robotically-Assisted Minimally Invasive Surgery (RA-MIS). The laboratory is jointly run by UWE and the University of Bristol.
Minimally Invasive (‘keyhole’) Surgery (MIS) has many advantages for the patient as it minimises disruption and contamination of the body tissues and damage to the skeleton, resulting in less pain, lower risk of infection and faster recovery. However it can make the work of surgeons harder as there is restricted access, which severely limits the number of effective ‘fingers’, or ‘hands’ that can actually work within the body cavity. This restricted access is mirrored as constrained movement of the surgeon’s shoulders and arms and can lead to strain injuries in those areas. Additionally the surgery can take up to twice as long as ‘open’ surgery.
Prof. Pipe demonstrated the tools used in MIS, essentially extended pliers and scissors, designed to fit within a 10 mm diameter access. These tools used a system of wires to transmit movement some 300 mm to the tool tip or end effector. This method allows them to be used alongside MRI scanners, unlike a motor-driven tip. However stretching of the wires and other wear means that the tools must be re-worked after about six operations at a cost of around £15k.
The da Vinci commercial robotic system was briefly described, allowing a surgeon to work at a desk remote from the operating table. The surgery itself being carried out by several ‘Puma’-type robotic arms fitted with MIS tools similar to those described earlier but with a degree of rotation on the end effector. Surprisingly an assistant was also required, at the table, to push organs out of the way with a wooden paddle.
One of the things that makes MIS harder for the surgeon is the lack of feedback and the inability to feel lumps etc. within soft tissues. Prof. Pipe described a three-fingered tool that the laboratory had been working on that was controlled by an exo-skeleton that fitted over the hand. Wires had been added to this framework that could be used to apply feedback forces. The laboratory was also working on a novel tactile sensor, which resembled an inside-out cashier’s rubber ‘thimble’, i.e. the ‘bobbles’ are on the inside. A miniature camera allows the position of the ‘bobbles’ to be determined as they are displaced by pressure on the outside tip of the ‘thimble’. Tests with gell-like simulations of soft tissues showed that this sensor is 97% as effective as a human finger in detecting buried ‘tumours’.
From the surgeon’s viewpoint MIS is clearly not without its problems, especially when treating soft-tissues where time in theatre can be doubled. The same was not true when treating multiple fractures. The conventional approach had been for the surgeon to find and mate the largest pieces of bone and pin them together and then to find the next largest piece and so on. This involved a lot of trial and error. Now it is possible to scan the fracture and ‘solve’ the ‘jig-saw’ off-line. MIS can then be used to directly place the bone segments in the correct position, halving the operation time.
Prof. Pipe said that they had a robotic solution to the bone-setting problem that they hoped to patent. He went on to describe a proof of concept model for a ‘pill’ that could pass through the body and ‘feel’ the tissue on the way. This model was similar to their fingertip sensor but egg-shaped. Ultimately they would hope to have an externally powered device that could be tracked through the body and, possibly, ‘backed-up’ if need be. Such a device could potentially deliver medication directly to the affected area, which would be especially useful for treating tumours.
In all this was a very interesting talk. We get used to new technologies producing improvements and while this is true for MIS from the patient’s point of view it is not necessarily the case for surgeons, as they need a far more training and then have to work longer and in a cramped state. However the introduction of robotics should certainly improve the lot of the surgeon and produce further benefits to the patient.
People talk of ‘disruptive technologies’ and, I think, image processing is definitely one of those. When I first became involved with robots we were intimidated by the amount of data that the human eye/brain combination appeared to process. Robotic ‘seeing’ was restricted to ‘beam-breaking’ or ‘bent lines’ detecting the height of objects on an assembly line. A TV camera cost the best part of a week’s wage and now it, (and the image processing!), form the basis of a neat tactile ‘fingertip’! This illustrates the ‘core message’ of technology, the rich inter-play of disciplines, in this case optics, electronics and mathematics. (And the manufacturing techniques that drive down costs, etc. etc.).
