A finite element model of the 3D-printed transparent facemask for applying pressure therapy

Preliminary Study on the Development of a Real-Time Pressure-Monitoring Facial Mask for Burn Rehabilitation

The most common aftereffect of severe burns in patients is hypertrophic scarring. Hypertrophic scars typically form following severe burns; it refers to excessive collagen production in the dermal layer during the healing process, resulting in an abnormal raised scar. Currently, practical treatments for suppressing hypertrophic scars include laser therapy, pressure therapy, and the application of silicone sheets for moisture retention. The most extensively used treatment involves compression therapy using specially designed garments for the affected areas. However, this method has limitations when applied to curved surfaces like the face. To address this issue, three-dimensional (3D) scanning and 3D printing techniques have been actively developed for face masks and have shown promising clinical results. Unfortunately, current facial masks under development lack a sensor system to measure pressure, making it difficult to ensure consistent and appropriate pressures during clinical trials. In this study, we have developed a burn pressure mask capable of real-time pressure monitoring. The facial mask developed in this study utilizes an FSR-type sensor to measure the pressure applied to the skin. We have also embedded electrical wires within the mask to enhance its comfort and wearability. For this study, two patients wore the facial mask with real-time pressure measurement capabilities for 4 weeks in 12 h per day on average. We evaluated whether the mask maintained the appropriate pressure range (15-25 mmHg) throughout the clinical trial and whether it effectively inhibited scar formation. Through the analysis of recorded pressure signal data, we confirmed that the patients consistently maintained the appropriate pressure while wearing the mask during the clinical trial. Additionally, we observed significant differences in skin moisture levels, transepidermal water loss, and scar thickness before and after the experiment. These findings suggest that the facial mask, featuring real-time monitoring capabilities, effectively prevents the formation of hypertrophic scars.

Utility of customized 3D compression mask with pressure sensors on facial burn scars: A single-blinded, randomized controlled trial

PURPOSE

A pressure of approximately 15-25 mmHg is used for effective compression therapy to prevent and treat hypertrophic scar formation in patients with burns. However, conventional facial compression garments present challenges owing to inadequate pressure distribution in curved areas such as the cheeks, around the mouth, and the slope of the nose. This study aimed to evaluate the utility of a custom-made 3D compression mask equipped with pressure sensors to treat facial burn scars.

METHODS

This single-blinded, prospective randomized controlled trial was conducted between May and October 2023, involving 48 burn scars in 12 inpatients with facial burns. We created the custom-made 3D compression mask equipped with pressure sensors, inner lined with biocompatible silicon, and a harness system using 3D printing technology, which can continuously monitor whether an appropriate pressure of 15-25 mmHg maintains. The biological scar properties, Vancouver Scar Scale (VSS), and Patient and Observer Scar Assessment Scale (POSAS) scores in patients with facial burns were assessed before applying the compression mask and garment and at 4 and 12 weeks after application.

RESULTS

Pre-application assessment of biological scar properties, VSS, and POSAS revealed no statistically significant differences between the 3D mask and control groups (p > 0.05 for all). Throughout the 12-week application, skin hydration and scar thickness significantly increased (p < 0.001) and reduced (p = 0.010), respectively, in the 3D mask group compared to the control group. Additionally, significant improvements in scar pliability (p = 0.004) and height (p = 0.009) of VSS, itching (p = 0.047), scar stiffness (p = 0.001), thickness (p = 0.011), and irregularity (p < 0.001) of POSAS-patient component, and scar thickness (p = 0.001), pliability (p = 0.012), and surface area (p = 0.027) of the POSAS-observer component were observed in 3D mask group throughout the 12-week application compared to the control group.

CONCLUSION

The customized 3D compression mask equipped with pressure sensors significantly improved scar thickness, skin hydration, and various assessment scale parameters throughout the 12-week application.

An automated design pipeline for transparent facial orthoses: A clinical study

STATEMENT OF PROBLEM

Transparent facial orthoses (TFOs) are commonly used for the treatment of craniomaxillofacial trauma and burns to prevent hypertrophic and keloid scarring. A TFO is typically customized to the patient's facial contours and relies on a precise fit to ensure good rehabilitative performance. A smart method of TFO design and manufacture is needed which does not require an experienced prosthetist, allowing for rapidly produced, well-fitting TFOs. Whether the rapid application reduces the final level of patient scarring is unclear.

PURPOSE

The purpose of this clinical study was to determine whether a scalable, automated design-through-manufacture pipeline for patient specific TFO fabrication would be successful.

MATERIAL AND METHODS

The automated pipeline received a 3-dimensional (3D) facial scan captured from a depth sensitive mobile phone camera. The scan was cleaned, aligned, and fit to a template mesh, with a known connectivity. The resultant fitted scan was passed into an automated design pipeline, outputting a 3D printable model of a custom TFO. The TFOs were fabricated with 3D printing and were both physically and digitally evaluated to test the fidelity of a digital fit testing system.

RESULTS

A total of 10 individuals were scanned with 5 different scanning technologies (STs). All scans were passed through an automated fitting pipeline and categorized into 2 groups. Each ST was digitally fitted to a ground truth scan. In this manner, a Euclidean distance map was built to the actual facial geometry for each scan. Heatmaps of 3D Euclidean distances were made for all participant faces.

CONCLUSIONS

The ability to automatically design and manufacture a custom fitted TFO using commercially available 3D scanning and 3D printing technology was successfully demonstrated. After considering equipment size and operational personnel requirements, vat polymerization (VP) technology was found to be the most promising route to TFO manufacture.