Revisiting a laryngoscope’s industrial design
Medical device design is experiencing a phenomenal growth, perhaps enabled by technology dissemination and new manufacturing methods. The World Health Organisation provides further clarity on growth patterns in their publication Medical devices: Managing the mismatch. However, their argument in the report is that medical device design focuses on, and is developed for, industrialized countries and not developing contexts. Incredibly they suggest that "up to three quarters of these devices do not function in their new settings (non-industrialised countries) and remain unused".
These figures stood out for me, in particular whilst reflecting on a laryngoscope I worked on in 1998 whilst working for the design firm SYZYGY. The design in question, was based on the principle of using a disposable transparent component to illuminate a patient's mouth and, among other requirements, inspect a patients larynx. Although the design received an SABS award, its ultimate market success was not in South Africa, but abroad. The reason being, that due to cost implications, South African surgeons would reuse the disposable blades until failure. Such reuse introduced a risk of component failure that had not been catered for in the design phase.
Fifteen years later, I wonder how the laryngoscope would have been designed if, not only the WHO recommendations of catering for lack of needs assessment, appropriate design, robust infrastructure, spare parts when devices break down, consumables, and a lack of information for procurement and maintenance were taken into account. Not only these requirements, but also the plethora of technologies and manufacturing processes that are now available to the designer and product user. The concept featured at the top of this page, and the image below, are a result of how this product could be re-conceived.
The concept challenges the design trajectories being deployed on recent laryngoscopes. For example, laryngoscopes commonly make use of screw-in type bulb or LEDs to illuminate the patients mouth, and more recently, video capability has been added to facilitate the analysis of detailed close-ups. Although such functionality is desirable, the specialist components and circuitry used necessitates a specific network of suppliers. Frequently, the resolution of such functionality on contemporary laryngoscopes ensures that standard autoclaves cannot be used for sterilisation due to the heat and steam potentially degrading the device.
In the concept shown above, a non-industrial system perspective has been used, and only key functionality fixed. The blade (curved component) encloses three optical fibres, and the handle and rear cap provide sealing and external connectivity. In other words, two of the optical fibres channel and project light from the handle light source to the tip of the laryngoscope blade, and the choice of illumination technology is up to the user who can fit an LED or bulb. The single and central optical fibre links the tip of the blade to the handle cap, where a coupling is made with an external video camera, or even a smart-phone camera with its own optical fibre link.
Perhaps the largest deviation this concept takes from traditional and contemporary laryngoscope designs, is that rather than using mass-production technologies such as injection moulding, this use of Computer Numeric Control (CNC) machining is used. The use of this process with production materials that embody a forging quality, such as Acrylonitrile butadiene styrene (ABS) and Stainless steel, somewhat ironically allows for maintenance and repairs to be carried out with hand-made process and equipment in remote areas.