A study evaluated the economic aspects of the manufacturing of 3D-printed hand orthoses compared to conventional low-temperature thermoplastic orthoses and found that the initial investment might be a hurdle in the implementation of 3D-printed devices, but that lower material cost and less waste is a benefit. They also noted that large-scale use of the infrastructure and developments in 3D printing technology might reduce future investment.
The researchers conducted a prospective cost minimization analysis from a healthcare provider perspective that included eight 3D-printed orthoses and nine low-temperature thermoplastic orthoses. They found that the mean cost per orthosis was higher in 3D-printed orthoses (€46.54 or $54.49 USD) than in the thermoplastic orthoses (€ 30.28 or $35.45 USD). The main cost factors in 3D-printed orthoses were the labor (62.2 percent) and purchase cost (22.2 percent), while the material (69.4 percent) and labor cost (30.6 percent) were most important in low-temperature thermoplastic orthoses.
To manufacture the 3D-printed orthoses, the affected limb was scanned by the therapist during the first appointment using an optical structure sensor (Mark I Structure Sensor, Occipital Inc.) rigged on a tablet. A purpose-built and CE-marked application (Spentys Point-of-Care Solution) was used to design the orthosis based on the scan by semiautomated modelling.
After converting the model of the orthosis into a Standard Tesselation Language (STL) file, the orthosis was printed in-house using Digital Light Processing technology with photosensitive resin (BASF Ultracur3D, ST45B, black).
Post-processing after printing included manually wiping off residual resin with ethanol and curing the orthosis with UV-light in a vacuum chamber (atum3D Curing Station; atum3D). The structural supports were then removed, and edges smoothed with sandpaper. During the second appointment, the orthosis was fitted to the patient, adding the Velcro straps. All steps were performed by hand therapists, with an average active time of approximately 45 minutes, while the printing took around 11 hours.
To manufacture the low-temperature thermoplastic orthoses, a pattern of the orthosis was drawn by the therapist on a spare plastic foil, using the hand and arm of the patient as template. The thermoplastic sheet (Klarity KS 3.2 mm, Klarity Medical & Equipment Co.) was then cut accordingly and heated for a few minutes in a water bath (WDB 6-100/4; Heuser Apparatebau) at a temperature of 70 degrees Celsius. Once heated and softened, the material was adjusted to the patient’s forearm and hand, and post-processed by cutting down overlaps, smoothing and correcting the edges using a heat gun, and adjusting the Velcro straps. The manufacturing of the orthosis was made in one therapy session, taking an average time of 14 minutes.
The open-access study, “Economic evaluation of the manufacturing of 3D-printed wrist orthoses vs. low temperature thermoplastic wrist orthoses,” was published in 3D Printing in Medicine.
