Digital workflow for fabrication of bespoke facemask in burn rehabilitation with smartphone 3D scanner and desktop 3D printing: clinical case study

Three-Dimensional Bioprinting Techniques in Skin Regeneration: Current Insights and Future Perspectives

Skin is composed of three layers: the epidermis, dermis, and hypodermis. It is enriched with skin appendages, including hair follicles, sweat glands, and sebaceous glands, which play essential roles in regulating fluid exchange, controlling body temperature, and providing protection against pathogens. Currently, skin regeneration treatments rely on transplantations. However, this approach has several disadvantages, including hemostasis at the recipient site, limitations in donor area closure, increased graft contraction, and hypertrophic scarring. Recent advancements in three-dimensional (3D) bioprinting technologies have enabled the fabrication of structures that closely mimic native tissues, with the aim of enhancing tissue regeneration. Bioprinting offers several advantages, such as high reproducibility, precision, and the ability to create complex geometries. The most promising bioinks combine excellent biocompatibility and biodegradability, with mechanical and rheological stability. This review highlights the most recent and innovative studies on 3D-printed bioinks in the field of skin tissue engineering. In particular, considering the growing interest in the regenerative potential of exosomes, we discuss cutting-edge research involving exosome-loaded bioinks and their potential to support skin regeneration and repair.

Learning program enhances rehabilitation professionals' perceived ease of using 3d printing: a pilot randomized controlled trial

The pilot study evaluated whether a learning program enhances a positive perception of 3D printing technology in rehabilitation professionals. Physical therapists, occupational therapists and speech-language-hearing therapists were recruited from a rehabilitation department in a middle-sized hospital. Participants were randomized to the control group (n = 13) or the intervention group (n = 14). An eight-week learning program consisted of a lecture on using a 3D printer and related software, a group discussion to integrate 3D printing into their clinical practices, and the implementation in their workplace. Outcome measures included the perception of 3D printing technology assessed by the Japanese version of the modified Technology Acceptance Model questionnaire for 3D printing technology (TAM-J). Assessment time points were pre-and post-intervention. As a result, all participants in the intervention group became capable of producing 3D-printed customized assistive devices. In the within-group analyses, the intervention group showed significant improvements in the TAM-J perception ease of use score (p = 0.012) with a large effect size (r = 0.75). Between-group analyses showed that the intervention group gained an additional improvement in the TAM-J perception ease of use score (p = 0.027) with a moderate effect size (r = 0. 43), indicating a significant improvement in the perceived ease of use of 3D printing technology in the intervention group. These observations suggest the 3D printing learning program could provide rehabilitation professionals with a positive perception of the technical aspect of 3D printing in their workplace.

Evaluating smartphone-based 3D imaging techniques for clinical application in oral and maxillofacial surgery: A comparative study with the vectra M5

PURPOSE

This study aimed to clarify the applicability of smartphone-based three-dimensional (3D) surface imaging for clinical use in oral and maxillofacial surgery, comparing two smartphone-based approaches to the gold standard.

METHODS

Facial surface models (SMs) were generated for 30 volunteers (15 men, 15 women) using the Vectra M5 (Canfield Scientific, USA), the TrueDepth camera of the iPhone 14 Pro (Apple Inc., USA), and the iPhone 14 Pro with photogrammetry. Smartphone-based SMs were superimposed onto Vectra-based SMs. Linear measurements and volumetric evaluations were performed to evaluate surface-to-surface deviation. To assess inter-observer reliability, all measurements were performed independently by a second observer. Statistical analyses included Bland-Altman analyses, the Wilcoxon signed-rank test for paired samples, and Intraclass correlation coefficients.

RESULTS

Photogrammetry-based SMs exhibited an overall landmark-to-landmark deviation of M = 0.8 mm (SD =  ± 0.58 mm, n = 450), while TrueDepth-based SMs displayed a deviation of M = 1.1 mm (SD =  ± 0.72 mm, n = 450). The mean volumetric difference for photogrammetry-based SMs was M = 1.8 cc (SD =  ± 2.12 cc, n = 90), and M = 3.1 cc (SD =  ± 2.64 cc, n = 90) for TrueDepth-based SMs. When comparing the two approaches, most landmark-to-landmark measurements demonstrated 95% Bland-Altman limits of agreement (LoA) of ≤ 2 mm. Volumetric measurements revealed LoA > 2 cc. Photogrammetry-based measurements demonstrated higher inter-observer reliability for overall landmark-to-landmark deviation.

CONCLUSION

Both approaches for smartphone-based 3D surface imaging exhibit potential in capturing the face. Photogrammetry-based SMs demonstrated superior alignment and volumetric accuracy with Vectra-based SMs than TrueDepth-based SMs.

Comparative evaluation of Artec Leo hand-held scanner and iPad Pro for 3D scanning of cervical and craniofacial data: assessing precision, accuracy, and user experience

AIM

This study compares the precision, accuracy, and user experience of 3D body surface scanning of human subjects using the Artec Leo hand-held scanner and the iPad Pro as 3D scanning devices for capturing cervical and craniofacial data. The investigation includes assessing methods for correcting 'dropped head syndrome' during scanning, to demonstrate the ability of the scanner to be used to reconstruct body surface of patients.

METHODS

Eighteen volunteers with no prior history of neck weakness were scanned three times in three different positions, using the two different devices. Surface area, scanning time, and participant comfort scores were evaluated for both devices. Precision and accuracy were assessed using Mean Absolute Deviation (MAD), Mean Absolute Percentage Error (MAPE), and Intra-Class Correlation Coefficients (ICC).

RESULTS

Surface area comparisons revealed no significant differences between devices and positions. Scanning times showed no significant difference between devices or positions. Comfort scores varied across positions. MAD analysis identified chin to chest measurements as having the highest variance, especially in scanning position 3. However, no statistical differences were found. MAPE results confirmed accuracy below 5% error for both devices. ICC scores indicated good reliability for both measurement methods, particularly for chin to chest measurements in positions 1 and 3.

CONCLUSION

The iPad Pro using the Qlone app demonstrates a viable alternative to the Artec Leo, particularly for capturing head and neck surface area within a clinical setting. The scanning resolution, with an error margin within ±5%, is consistent with clinically accepted standards for orthosis design, where padding and final fit adjustments allow for bespoke devices that accommodate patient comfort. This study highlights the comparative performance of the iPad, as well as suggests two methods which can be used within clinics to correct head drop for scanning.

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.

Application of 3D Transparent Facemasks in Long-Term Outpatient Rehabilitation of Facial Scars After Burns: A Retrospective Cohort Study of Improved Appearance of Target Scars With Different Healing Time

Severe facial burns may cause scarring problems and affect living quality of patients. With the advent of 3D facemasks, it is being used to treat facial scars; however, its efficacy must be confirmed by adequate studies. A retrospective analysis of 26 patients who visited rehabilitation outpatient clinic from 2017 to 2022. Patients were separated into two groups based on the time to healing (TTH) following burn injury: early healing group (TTH ≤ 21 days) and late healing group (TTH > 21 days). To compare treatment outcomes and differences between the two groups, 3D facemask application was assessed using the Vancouver Scar Scale (VSS), patient satisfaction, and complications. In both groups, there were significant improvements in the total VSS scores (P < .01) and each VSS subscore (P < .01). These scar characteristics improved over time as the treatment progressed. Compared with the late healing group, the early healing group had more obvious effects on improving scar pigmentation (P < .05) and vascularity (P < .05) at similar assessment time points after burns. At the last assessment, there was a significant difference in total VSS scores between groups (P = .009). For the early and late healing groups, respectively, the mean gradient value (SE) of the total VSS scores was 1.550 (0.373) and 1.283 (0.224) over the course of the treatment periods. 3D facemasks are effective in the rehabilitation of facial scars caused by burns, which should be used for prevention and treatment in the initial stages of scar development.

Workflow to develop 3D designed personalized neonatal CPAP masks using iPhone structured light facial scanning

Background

Continuous positive airway pressure (CPAP) is a common mode of respiratory support used in neonatal intensive care units. In preterm infants, nasal CPAP (nCPAP) therapy is often delivered via soft, biocompatible nasal mask suitable for long-term direct skin contact and held firmly against the face. Limited sizes of nCPAP mask contribute to mal-fitting related complications and adverse outcomes in this fragile population. We hypothesized that custom-fit nCPAP masks will improve the fit with less skin pressure and strap tension improving efficacy and reducing complications associated with nCPAP therapy in neonates.

Methods

After IRB approval and informed consent, we evaluated several methods to develop 3D facial models to test custom 3D nCPAP masks. These methods included camera-based photogrammetry, laser scanning and structured light scanning using a Bellus3D Face Camera Pro and iPhone X running either Bellus3D FaceApp for iPhone, or Heges application. This data was used to provide accurate 3D neonatal facial models. Using CAD software nCPAP inserts were designed to be placed between proprietary nCPAP mask and the model infant’s face. The resulted 3D designed nCPAP mask was form fitted to the model face. Subsequently, nCPAP masks were connected to a ventilator to provide CPAP and calibrated pressure sensors and co-linear tension sensors were placed to measures skin pressure and nCPAP mask strap tension.

Results

Photogrammetry and laser scanning were not suited to the neonatal face. However, structured light scanning techniques produced accurate 3D neonatal facial models. Individualized nCPAP mask inserts manufactured using 3D printed molds and silicon injection were effective at decreasing surface pressure and mask strap pressure in some cases by more than 50% compared to CPAP masks without inserts.

Conclusions

We found that readily available structured light scanning devices such as the iPhone X are a low cost, safe, rapid, and accurate tool to develop accurate models of preterm infant facial topography. Structured light scanning developed 3D nCPAP inserts applied to commercially available CPAP masks significantly reduced skin pressure and strap tension at clinically relevant CPAP pressures when utilized on model neonatal faces. This workflow maybe useful at producing individualized nCPAP masks for neonates reducing complications due to misfit.