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Usability for medical devices is moving to the forefront of many manufacturers’ design approaches, as it has changed from being viewed as just another ’regulatory hurdle’ to an integral process implemented throughout development. It can often take time, however, for such shifts to propagate backwards to academia and be adopted and supported across the board.

Having attended the AAMI Human Factors for Medical Devices course earlier this year, I was interested to note whether usability would be high on the agenda at the International Society for Computer Assisted Orthopaedic Surgery annual meeting in Vancouver, Canada. Having presented research at the previous two meetings and as a named contributor on additional research this year, I was keen to catch up on the current clinical and research issues in the industry.

Computer assisted orthopaedic surgery (CAOS) is an active clinical and research space where computer science, engineering, and robotics principles are applied to traditional orthopaedic procedures with the goal of improving operative and post-operative outcomes. For instance, when a patient receives a joint replacement, the surgeon can use CAOS technology to preoperatively plan the implant size and location, interoperatively track and/or guide the placement of the implant, and determine post-operatively how closely the procedure adhered to the preoperative plan, providing insight into the long-term survivability of the implant.

It is a focused application of the broader field of computer assisted surgery (CAS), which includes the creation of accurate 3D models of patient anatomy from medical scans, diagnostics and preoperative planning, surgical simulation, interoperative navigation, and finally robotic surgery. The field as a whole aims to use technology to deliver greater surgical precision and better operative outcomes for the patient.

Perhaps the most recognisable application of CAS technology is Intuitive Surgical’s da Vinci Surgical System, films of which can be viewed on YouTube peeling a grape or folding a paper crane. The system was designed to facilitate complex minimally invasive surgery while being controlled remotely and it can be argued that much of the initial commercial traction from the system was due to its ease of use and reduction of physical exertion, rather than a clearly demonstrated superiority to traditional operational approaches, which has largely been the case for subsequent CAS adoption. 

This is still cutting edge technology and isn’t supported everywhere. Publically-funded healthcare systems like those in Canada and the UK, while employing a number of da Vinci systems, tend to shy away from the cutting edge of medtech, favouring technology with firmly established safety and efficacy. 

There was interesting debate around how technological advancement without demonstration of superiority to the gold standard of care is unlikely to gain market traction in publically funded healthcare systems. Particularly as the ability to compare a new intervention to the gold standard of care remains a challenge as surgeon preference carries as much weight as peer-reviewed publication in determining functional outcomes. This discussion led onto what I believed was the primary takeaway from the conference: the importance of human factors and usability when designing complex computer assisted surgery systems. Will usability drive the adoption of these new technologies to a broader audience?

These systems have always been accurate. It’s whether or not they’ve been easy to use” said an American surgeon during one session. Looking back at some of the early CAS and CAOS systems, it’s easy to see why early adopters abandoned the technology. Requiring around 10-15 cases before a surgeon can achieve the required accuracy of implantation, or adding 30+ minutes to an intervention (which would reduce the total number of operations a surgeon can do in a day) are complications that have understandably caused rejection of CAS adoption by surgeons. These are the kind of issues that are driving manufacturers to integrate usability into their technical product requirements – so that the benefits can be more clearly perceived without impacting on a surgeon’s workload.

Companies like Exactech are moving optical trackers and touchscreens into the sterile field to reduce occlusion and system interaction problems, while Intellijoint mounts a single camera directly to the patient’s hard tissue and uses removable optical markers to improve the surgeon’s ability to physically navigate the operating field.

CAOS technologies have long been viewed as a nuisance, impacting the entire surgical timeline, from cleaning and sterilization, through setup, and finally during the intervention. With the final version of the FDA’s Human Factors for Medical Devices Guidance due out in the near future, factors such as increasing recognition of AAMI/IEC 62366, and a willingness from healthcare institutions to consider increased capital costs when they’ve been demonstrated to benefit the institution in the long run, are making a positive impact towards acceptance.

I believe that we’ll begin to see CAS and CAOS adoption rates increase in the coming years but only if manufacturers begin to leverage usability as a mechanism for winning over surgeons who have abandoned or refuse to allow the technology into their operating theatres.

If you’d like to talk to us about human factors for medical devices, please contact our human factors/usability specialists or our medical device team: or call 01223 264428

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