Three-Dimensional Analysis of Donor Masks for Facial Transplantation:

Computerized Surgical Planning in Face Transplantation

Face transplantation (FT) has emerged as a critical intervention for patients with complex facial deformities unsuitable for conventional reconstructive methods. It aims to restore essential functions such as facial expression, mastication, and speech, while also improving psychosocial health. The procedure utilizes various surgical principles, addressing unique challenges of craniofacial complexity and diverse injury patterns. The integration of Computerized Surgical Planning (CSP) leverages computer-aided technologies to enhance preoperative strategy, intraoperative navigation, and postoperative assessment. CSP utilizes three-dimensional computed tomography, printing, angiography, and navigation systems, enabling surgeons to anticipate challenges and reduce intraoperative trial and error. Through four clinical cases, including a groundbreaking combined face and bilateral hand transplant, CSP's role in FT is highlighted by its ability to streamline operative processes and minimize surgical revisions. The adoption of CSP has led to fewer cadaveric rehearsals, heightened operative precision, and greater alignment with preoperative plans. Despite CSP's advancements, it remains complementary to, rather than a replacement for, clinical expertise. The demand for technological resources and multidisciplinary teamwork is high, but the improved surgical outcomes and patient quality of life affirm CSP's value in FT. The technology has become a staple in reconstructive surgery, signaling a step forward in the evolution of complex surgical interventions.

Oculopalpebral prosthesis prototype design using the additive manufacturing technique: A case study

Three-dimensional (3D) printing technology has advanced for applications in the field of reconstructive surgery. This study reports the application of a comprehensive methodology to obtain an anatomical model, using computed tomography and 3D printing, to treat a patient with cancer who designed a prototype oculopalpebral prosthesis for the reconstruction of the affected area of the face (left eye). A personalized prototype was obtained, which adapted to the face of the person, and improved the aesthetics and quality of life. The applied techniques helped to make definitive prostheses using materials that could be permanent. The training and tests carried out in this study favored the understanding and assimilation of the technology and the possibility of applying it to patients in need of facial prosthetic rehabilitation.

Using Smartphone Exophthalmometry to Measure Eyeball Protrusion

Importance

The current clinical criterion standard for measuring abnormal eyeball protrusion is still the historic Hertel exophthalmometer, which is prone to reading errors. Therefore, a smartphone application has been developed to measure exophthalmos.

Objective

To evaluate a relatively simple noninvasive measurement method for exophthalmos using a smartphone.

Design, Setting, and Participants

This cross-sectional study compared smartphone exophthalmometry with the existing reference standard, the Hertel exophthalmometer, or a professional high-resolution 3-dimensional scanner. Participants were patients with exophthalmos due to Graves orbitopathy and other intraorbital conditions and healthy volunteers who were recruited between June 2019 and January 2022 from the Department of Ophthalmology, University Hospital Zurich.

Interventions

All participants were examined twice by 3 different operators using 3 different methods (smartphone, high-resolution scanner, or Hertel exophthalmometer) at an interval of a minimum of 2 weeks or after exophthalmos-changing treatment.

Main Outcome Measures

Accuracy and precision, test-retest reliability, and interoperator reliability of eyeball protrusion measurements obtained with the smartphone compared to the Hertel exophthalmometer and the high-resolution face scanner.

Results

Of 39 participants, 23 patients (median [IQR] age, 54 [44-59] years; 15 [65%] female and 8 [35%] male) showed a mean difference in eyeball protrusion of 3.3 mm and 16 healthy volunteers (median [IQR] age, 32 [30-37] years; 11 [69%] female and 5 [31%] male) of 0.8 mm without any significant difference between the 3 methods. Accuracy and precision agreement between exophthalmos measures with the smartphone and the Hertel exophthalmometer showed an intraclass correlation coefficient (ICC) of 0.89 (95% CI, 0.80-0.94) and 0.93 (95% CI, 0.83-0.97) for the high-resolution scanner. Interoperator agreement was highest for the high-resolution scanner (ICC, 0.99 [95% CI, 0.98-0.99]), followed by the smartphone (ICC, 0.95 [95% CI, 0.92-0.97]) and the Hertel exophthalmometer (ICC, 0.91 [95% CI, 0.85-0.95]). Test retest reliability was similarly high for the smartphone (ICC, 0.93 [95% CI, 0.82-0.95]), the Hertel exophthalmometer (ICC, 0.92 [95% CI, 0.83-0.96]), and the high-resolution scanner (ICC, 0.95 [95% CI, 0.89-0.97]).

Conclusions and Relevance

The findings of this study demonstrate relatively high accuracy and precision, interoperator reliability, and test-retest reliability for smartphone exophthalmometry. These data support the use of a smartphone in place of a Hertel exophthalmometer for measuring exophthalmos in the future.

Three-dimensional morphometric analysis of facial units in virtual smiling facial images with different smile expressions

PURPOSE

Accuracy of image matching between resting and smiling facial models is affected by the stability of the reference surfaces. This study aimed to investigate the morphometric variations in subdivided facial units during resting, posed and spontaneous smiling.

MATERIALS AND METHODS

The posed and spontaneous smiling faces of 33 adults were digitized and registered to the resting faces. The morphological changes of subdivided facial units at the forehead (upper and lower central, upper and lower lateral, and temple), nasal (dorsum, tip, lateral wall, and alar lobules), and chin (central and lateral) regions were assessed by measuring the 3D mesh deviations between the smiling and resting facial models. The one-way analysis of variance, Duncan post hoc tests, and Student's t-test were used to determine the differences among the groups (α = .05).

RESULTS

The smallest morphometric changes were observed at the upper and central forehead and nasal dorsum; meanwhile, the largest deviation was found at the nasal alar lobules in both the posed and spontaneous smiles (P < .001). The spontaneous smile generally resulted in larger facial unit changes than the posed smile, and significant difference was observed at the alar lobules, central chin, and lateral chin units (P < .001).

CONCLUSION

The upper and central forehead and nasal dorsum are reliable areas for image matching between resting and smiling 3D facial images. The central chin area can be considered an additional reference area for posed smiles; however, special cautions should be taken when selecting this area as references for spontaneous smiles.

Validating a Novel Device to Improve Skin Color Matching for Face Transplants

Facial vascularized composite allotransplantation (VCA) offers an added layer of complexity when compared to solid organ transplantation. VCAs must account for aesthetic variables such as skin tone and color. The goal of this study is to validate the Nix Color Sensor as a novel tool to be added to the plastic surgeon's armamentarium for evaluating skin color match of the donor and recipient.

METHODS

A prospective study of 100 individuals was conducted. All participants were photographed and scanned with the Nix Color Sensor. Sixty pairwise comparisons were randomly generated. Skin color analysis was performed using photographs and the Nix Color Sensor. Delta E2000 values were compared to mean evaluator ratings using a Spearman correlation analysis.

RESULTS

One hundred patients were included. A Spearman's correlation demonstrated a strong inverse correlation between Delta E2000 values and the mean evaluator ratings. The higher the mean evaluator rating for likeness, the lower the delta. A correlation coefficient of -0.850 demonstrates a statistically significant relationship (P < 0.01).

CONCLUSIONS

When the Delta E2000 rises above 5 there is a significant drop in the mean evaluator ratings. As mean evaluator ratings of 5 and above would be considered adequate for face transplant amongst most plastic surgeons, an E2000 value of 5 or lower should be targeted when matching donors with recipients for face transplant. The Nix Color Sensor positively correlates to the plastic surgeon's perception of skin color and can serve as an adjunct in donor selection for facial VCAs.

The First Successful Combined Full Face and Bilateral Hand Transplant

BACKGROUND

Vascularized composite allotransplantation has redefined the frontiers of plastic and reconstructive surgery. At the cutting edge of this evolving paradigm, the authors present the first successful combined full face and bilateral hand transplant.

METHODS

A 21-year-old man presented for evaluation with sequelae of an 80 percent total body surface area burn injury sustained after a motor vehicle accident. The injury included full face and bilateral upper extremity composite tissue defects, resulting in reduced quality of life and loss of independence. Multidisciplinary evaluation confirmed eligibility for combined face and bilateral hand transplantation. The operative approach was validated through 11 cadaveric rehearsals utilizing computerized surgical planning. Institutional review board and organ procurement organization approvals were obtained. The recipient, his caregiver, and the donor family consented to the procedure.

RESULTS

Combined full face (i.e., eyelids, ears, nose, lips, and skeletal subunits) and bilateral hand transplantation (i.e., forearm level) was performed over 23 hours on August 12 to 13, 2020. Triple induction and maintenance immunosuppressive therapy and infection prophylaxis were administered. Plasmapheresis was necessary postoperatively. Minor revisions were performed over seven subsequent operations, including five left upper extremity, seven right upper extremity, and seven facial secondary procedures. At 8 months, the patient was approaching functional independence and remained free of acute rejection. He had significantly improved range of motion, motor power, and sensation of the face and hand allografts.

CONCLUSIONS

Combined face and bilateral hand transplantation is feasible. This was the most comprehensive vascularized composite allotransplantation procedure successfully performed to date, marking a new milestone in plastic and reconstructive surgery for patients with otherwise irremediable injuries.

Attitudes May Be Hard to Change: Canadian Organ Donors Consider Face and Hand Donation

Despite the success of composite tissue allograft (CTA) such as face and hand transplant at improving recipients’ quality of life, organ donors’ hesitation needs to be better understood. The aim of the study was to assess Canadian organ donors’ willingness to donate their face and hands, and the efficacy of an educational intervention.

Facial Transplantation: Principles and Evolving Concepts

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Appreciate the evolution and increasing complexity of transplanted facial allografts over the past two decades. 2. Discuss indications and contraindications for facial transplantation, and donor and recipient selection criteria and considerations. 3. Discuss logistical, immunologic, and cost considerations in facial transplantation, in addition to emerging technologies used. 4. Understand surgical approaches and anatomical and technical nuances of the procedure. 5. Describe aesthetic, functional, and psychosocial outcomes of facial transplantation reported to date.

SUMMARY

This CME article highlights principles and evolving concepts in facial transplantation. The field has witnessed significant advances over the past two decades, with more than 40 face transplants reported to date. The procedure now occupies the highest rung on the reconstructive ladder for patients with extensive facial disfigurement who are not amenable to autologous reconstructive approaches, in pursuit of optimal functional and aesthetic outcomes. Indications, contraindications, and donor and recipient considerations for the procedure are discussed. The authors also review logistical, immunologic, and cost considerations of facial transplantation. Surgical approaches to allograft procurement and transplantation, in addition to technical and anatomical nuances of the procedure, are provided. Finally, the authors review aesthetic, functional, and psychosocial outcomes that have been reported to date.

Anesthetic Considerations in Facial Transplantation: Experience at NYU Langone Health and Systematic Review

Anesthetic considerations are integral to the success of facial transplantation (FT), yet limited evidence exists to guide quality improvement. This study presents an institutional anesthesia protocol, defines reported anesthetic considerations, and provides a comprehensive update to inform future directions of the field.

Review of Plastic Surgery Biomaterials and Current Progress in Their 3D Manufacturing Technology

Plastic surgery is a broad field, including maxillofacial surgery, skin flaps and grafts, liposuction and body contouring, breast surgery, and facial cosmetic procedures. Due to the requirements of plastic surgery for the biological safety of materials, biomaterials are widely used because of its superior biocompatibility and biodegradability. Currently, there are many kinds of biomaterials clinically used in plastic surgery and their applications are diverse. Moreover, with the rise of three-dimensional printing technology in recent years, the macroscopically more precise and personalized bio-scaffolding materials with microporous structure have made good progress, which is thought to bring new development to biomaterials. Therefore, in this paper, we reviewed the plastic surgery biomaterials and current progress in their 3D manufacturing technology.

3D Printing as a Significant Achievement for Application in Posttraumatic Surgeries - A Literature Review

BACKGROUND

3D printing is increasingly used in many fields of medicine. The broadening of knowledge in this field and the cooperation of doctors and engineers increase the interest in this technology and results in attempts to implement it at every stage of the treatment.

OBJECTIVE

The review aims to summarize the current literature on the use of 3D printing technology in the treatment of post-trauma patients.

METHODS

A review of available scientific publications in PubMed regarding 3D printing and its application in the context of posttraumatic procedures was carried out. Clinical Trials and Reviews from the period 2014-2019 (6-year period) were taken into consideration. The database was searched for "Printing", "ThreeDimensional" [MAJR] [MeSH Term]. Finally, 48 studies have been included in our review article.

RESULTS

3D printing technology has a number of applications in patients who have suffered injuries. 3D printing has found application in the preparation of procedures, accurate visualization of occurring injuries and complications, education of doctors and patients, prototyping, creation of synthetic scaffolding, production and implementation of target implants and rehabilitation.

CONCLUSION

3D printing is increasingly used in providing for posttraumatic patients. It is necessary to conduct further research in this area and to provide development opportunities regarding biopolymers and bioprinting. It is also necessary to improve cooperation between doctors and engineers and to create new centres that can comprehensively use 3D printing - from imaging diagnostics to the production of implants and their surgical use.

Digital dentistry: The new state of the art - Is it disruptive or destructive?

OBJECTIVE

Summarizing the new state of the art of digital dentistry, opens exploration of the type and extent of innovations and technological advances that have impacted - and improved - dentistry. The objective is to describe advances and innovations, the breadth of their impact, disruptions and advantages they produce, and opportunities created for material scientists.

METHODS

On-line data bases, web searches, and discussions with industry experts, clinicians, and dental researchers informed the content. Emphasis for inclusion was on most recent publications along with innovations presented at trade shows, in press releases, and discovered through discussions leading to web searches for new products.

RESULTS

Digital dentistry has caused disruption on many fronts, bringing new techniques, systems, and interactions that have improved dentistry. Innovation has spurred opportunities for material scientists' future research.

SIGNIFICANCE

With disruptions intrinsic in digital dentistry's new state of the art, patient experience has improved. More restoration options are available delivering longer lifetimes, and better esthetics. Fresh approaches are bringing greater efficiency and accuracy, capitalizing on the interest, capabilities, and skills of those involved. New ways for effective and efficient inter-professional and clinician-patient interactions have evolved. Data can be more efficiently mined for forensic and epidemiological uses. Students have fresh ways of learning. New, often unexpected, partnerships have formed bringing further disruption - and novel advantages. Yes, digital dentistry has been disruptive, but the abundance of positive outcomes argues strongly that it has not been destructive.