The business was formed initially for the purpose of developing an alternative to the Plaster of Paris (PoP) method for limb immobilisation based on earlier R&D on polymeric materials that would phase change from solid to malleable gel and back again to a solid in the temperature range 37 degrees (normal body temperature) to 55/56 degrees (comfortable for human tolerance).
To determine the viability of the torc2 system for replacing PoP, discussions were held with The University of Warwick Medical School’s Orthopaedic specialists who were unanimous in their praise of the concept but felt that the most effective use for the system would be in niche splinting applications.
At the second round of talks we were presented with a set of slides indicating their “wish list” regarding the areas where the properties of the material would have significant impact on issues relating to time for manufacture, fit, comfort and re-use. These areas included Ankle Foot Orthosis (AFO), Hip Spica, and Prosthetic Socket.
Following these revelations the focus of the company was re-directed along the splinting route and a seed investor sought to provide early working capital for prototype development of the AFO, which was the first item on the “wish list”.
This existing modelling process for this item relies mainly on taking a plaster cast of the limb which is removed by cutting in two, then a silicone pattern of the inside of the cast is made which is then sent off-site to be used by an Orthotics Company to shape a high temperature plastics splint from sheet material. This results in an inefficient system which can take up to 3 months and where one third of AFOs have to be returned for refits as there is little or no ability to adjust directly on the patient.
For the hip spica cast the key issues that were highlighted relate to the use of general anaesthesia in theatre to re-fit a new cast when the treatment extends beyond a 5-6 weeks period, the availability of theatre should an emergency arise, major problems with hygiene, and the high cost of the theatre/medical team each time the cast has to be removed and replaced.
The third item was a prosthetic socket for lower limb amputees where the major issue is the need for a really close fit of the socket to the residual limb to avoid pressure sores developing. Since the residual limb shape frequently changes the ideal socket will be one that can be easily altered by the amputees themselves without the need for continual visits to their orthotist.
The solution to most of the problems identified by the clinicians is a system of modelling directly onto affected limbs using the torc material that can be re-shaped many times at 56-60 degrees C but which on cooling back to body temperature becomes a rigid support structure again.
Following early R&D work a materials blend was eventually created and tested at the temperature range required using a DMTA (Dynamic Mechanical Thermal Analysis) machine at The University of Warwick’s Digital Lab.
Each splint or movement restricting cast requires a specific means of heating to get to the temperature at which the shape may be changed. Where the heating system is built into the device appropriate thermostatic protection will also be built in so that the patient is not exposed to an unacceptable risk of burning due to overheating.
In the case of the AFO, should any minor change be needed, the heating method will be external and under the control of the fitting technician. Where there is a need for extreme rigidity the AFO can be produced with stiffening pieces in precisely the areas as directed by the consulting clinician rather than by simply increasing the material thickness. Working with Warwick Manufacturing Group and The Manufacturing Technology Centre additive layer manufacturing methods will be harnessed to create 3-D printed splints. The use of this latest technology in conjunction with the torc2 material will allow the manufacture of bespoke orthotics within hours instead of weeks.
In-built heating for the hip spica and prosthetic sockets will be effected mostly by embedded flexible silicone heater systems monitored and controlled by sensors for thermostatic temperature control and for providing either a wired or wireless output/display for additional safety or recording purposes. Further development to 3-D printed heater circuits and sensors will follow as this technique becomes more commercially viable.
In the case of the hip spica cast, which is most often used to treat severe hip dysplasia in infants and very young children, the torc2 version will allow the clinician to carry out refits necessitated by growth in an outpatient/clinic environment without the need for a costly theatre team and the risks associated with repeated anaesthesia.
The torc2 hip spica system, when fully developed, will offer the following benefits;
- Safe and easy shaping to patient for best fit.
- Can be fitted/refitted in a single visit to an outpatient department or clinic.
- Multi-zoned heater control for releasing individual areas that require examination or adjustment for growth.
- Re-usable many times.
- Water resistant for showering or swimming.
- Impact cushioning to reduce effect of knocks.
- Wash/wipe clean surfaces for good hygiene.
- Anti-microbial formulations available for reducing infection.
- Suitable for embedding sensors and communication chips.
The prosthetic socket device will also have a built-in heater accessible via a mains AC to DC adapter so that amputees themselves may easily make shape changes for best fit to the residual limb end as often as needed. The malleable section will reshape to the new 3-D contours to provide an accurate fit and reduce the potential of high spots causing pressure sores.
The torc system is the subject of the following Patent applications: