Following a fascinating conversation with a Senior Orthotist, I thought I would offer his thinking on the future of casting for orthoses.
His answer to the question above was – NO! He went on to say.
We are not talking about replacing it with direct scanning, which is as popular as ever with AM technology, but the next step, which is the use of smart textiles.
Be prepared in the next decade to reminisce with a new era of O and P graduates, as they hold back the laughter on how we wrapped limbs in POP to purely gain an accurate 3D shape. Even as the decade passes, we will likely not be looking back at POP (or whatever other casting medium) with rose tinted glasses, as it is and always has been just a pain – from the process of applying, time to cure and to remove, via means of scissors (uncomfortable), knife or scalpel (dangerous and intimidating). Ask any of your clients, or more specifically challenging paediatric clients if they fondly remember their first casting experiences; the answer will likely be no. It just isn’t a nice experience or product, for the purpose in which we are using it – 3D shape capture.
The use POP or polyester in Orthotics requires significant skill, logistics and post-processing to generate a positive cast that is optimum. It’s wasteful on so many levels; add to this a bubbling anxiety that you may see a plastic insert from literally thousands of finished POP rolls lodged in a sea mammal in an Attenborough documentary, it’s time we moved on.
Anyone who is scanning will already understand that although it has obvious benefits, it does still in fact have nuances and it is not suitable for every client. Here are some of the issues in no particular order; cost, movement rendering capture unusable, the physicality of getting around a limb even with something like a structure 2 sensor and tablet is difficult and certainly for most children (or those with sensory or spasticity) you are going to need a second pair of hands to physically hold that limb in the ideal position. The last is often where people resist or dismiss direct scanning, as they feel this disconnect of ‘feel’. The physical tactile connection of holding and correcting a limb, sensing a feel for range, resistance, soft tissue and in many respects they are correct as some limbs still need human interaction.
The answer will likely be Smart textiles. This is not a new area, as many plantar measuring socks exist and the world of robotics is littered with different systems. The newer systems are typically Smart Embedded Cooperative Systems of often a matrix structure equipped with a set of stretchable biocompatible multi-modal sensors systems, which are mechanically flexible and unobtrusive or more recently optoelectronic sensing.
The next step for example with AFO casting, would be to simply be able to fit an AFO casting sock onto a client. The smart, portable and stretchable textile sleeve with integrated sensors will connect to a smartphone to visualize a digital limb model which can be saved and exported for manufacture. This will undoubtedly be ground breaking, not limited to just workflow in day to day saving of time, but the whole process just being far more pleasant for clinician and client. We should have the ability to have a client stand in a shoe and capture pitch for a desired shoe, the ability to still be able to hold and correct a limb, with multiple casts being able to be done in a matter of seconds until settling on the final alignment you’re seeking, with increased accuracy and no waste, it’s a win win.
What of the future after this? What really is exciting are the multi modal qualities of sensors, measuring anything from PH, temperature, or deformation. The ideal would be the impact of wearing a sensor sock to gain not just 3D capture, but motion capture of joints and plantar pressures. To then pull all of this together to send full biometrics that can be interpreted and analysed to bring together an ideal prescription from simply donning a textile sock, or any part of the body for that matter. We may even see these sensors embedded into our wearable orthoses and prostheses to gain real time data, pressure warnings as well as monitoring of diseases and pathology over time.
There are considerable challenges to overcome before extending this technology beyond three-dimensional (3D) capture. To note; the continuum of joint angles, and the hysteretic properties of the matrix elastomers with conductive materials produce varying conductivities during cyclic loading. Either way, I can’t wait for it to replace traditional casting.
Would you happily adopt smart textiles for casting?
