Although isolation masks are associated with less discomfort compared to N95 respirators, a prior study demonstrated that healthcare providers’ discomfort increases with prolonged use (greater than 2 hours) of wearing isolation-type masks with ear loops and that the discomfort continues to increase on a per-hour basis (3). The mask extender design allows for isolation masks to be secured behind the posterior aspect of the pinna without exerting direct pressure on it, diffusing that pressure broadly across the posterior aspect of the head. This design, first posted online to the National Institutes of Health 3D Printing Exchange (4), has been modified by the authors by lengthening it and adding additional rungs to increase comfort and increased ability to adjust the tension of the straps to achieve a more individualized fit. The combined relief of pressure with tension control decreases discomfort and irritation from mask designs with ear loops. As mask utilization continues to increase among healthcare providers in every setting and among the lay public, this is especially relevant as increasing wearability and decreasing discomfort may increase compliance with the infection control and public health guidelines put forth by local and national institutions.
The modified 3D printed mask extender in the current study was based on a design submitted to the NIH 3D Print Exchange by Davis Becker, an innovation specialist with the VHA Innovation Ecosystem (3, 4). The original design was created from Quinn Callander, a 13-year old boy scout from Maple Ridge, British Columbia (10). That deign was then modified by Ken Lord (11). From feedback from the frontline staff of the mask extender design, one of the authors (ZO) modified to extend the length and add extra rungs to account for the larger cranial sizes and staff with larger volumes of hair.
This design is part of a larger movement of community generated 3D printed solutions to novel issues and supply chain shortages that arose with the advent of this pandemic including ventilator components, personal protective equipment such as splash-proof face shields, surgical masks, N95 masks, N90 masks, powered air-purifying respirator hoods, and controlled air purifying respirator hoods, and environmental solutions such as door handle modifications (5). 3D printing has attempted to solve this issue by facilitating manufacturing of ad hoc personal protective equipment as well as medical equipment during the COVID-19 pandemic (6-8). These efforts have included producing face shields5, innovative ventilator solutions (7), among others. The FDA have issued caution with 3D printed personal protective equipment (8), but they have expressed willingness to work with individuals and entities producing such alternatives and are currently working with the NIH 3D print exchange (8).
Limitations to this work include obtaining formal survey data from wearers and comparing user comfort or discomfort levels compared to not wearing a mask extender. Similar interventions in the 3D printing of face shields for interventional radiologists have been thoroughly evaluated and found to not produce any detriment to ability of physicians to perform their duties while solving the supply chain shortage of personal protective equipment (9). Alternative materials can be used to 3D print these mask extenders. While we used PLA a semi-rigid to rigid polymer, polyethylene terephthalate glycol (PETG) is a more flexible material that is likely well-suited for the extenders; intended purposes. While we considered and explored using PETG polymer, at the time of the study (early COVID-19 pandemic - mid March to late May 2020), PETG was in limited supply and being used at our institution for 3D printed face shields. Furthermore, PETG requires higher print temperature settings for the nozzle and build plate, resulting in slower print speeds and overall longer printer times. These factors may not be optimal for mass production using few desktop 3D printers. For the mask extender design, the anecdotal support and metrics of satisfaction, including personal feedback and requests to produce more mask extenders, have been overwhelmingly positive, and the authors of this study thought it appropriate to share these results to offer this solution to a broader audience as well as encourage continued utilization and modification of 3D printed solutions as the world continues to grapple with the COVID-19 pandemic. Potential improvements to the 3D printed mask extender in the current study may be reducing the number of rungs and decreasing the material volume for faster print speeds and lighter weight of the extender.
In conclusion, the authors offer a modification of a 3D printed mask extender design that decreases discomfort and increases the wearability of isolation mask designs with ear loops thought to relieve posterior auricular skin pressure and ability to control strap tension. The design is simple, produced with inexpensive material (polylactic acid), and have been well-received by healthcare providers at our institution. The authors offer their design, which others may adapt.