Found in space: computer-assisted orthognathic alignment of a total face allograft in six degrees of freedom

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.

In Vivo Accuracy of a New Digital Planning System in Terms of Jaw Relation, Extent of Surgical Movements and the Hierarchy of Stability in Orthognathic Surgery

This retrospective cohort study compares the virtual planned and postoperative jaw positions in patients undergoing orthognathic surgery. Surgery was virtually planned with the Digital Münster Model Surgery system (DMMS). Primary outcome: Spatial difference in the maxillo-mandibulo relation between virtual planning and postoperative result. Secondary outcome: Possible relationship between the measured differences and surgical movements as well as the postoperative stability according to Proffit. Ninety female and sixty-one male patients were included in the study. The average translation errors were 0.54 ± 0.50 mm (anteroposterior), 0.37 ± 0.33 mm (mediolateral), and 0.33 ± 0.28 mm (superoinferior). Orientation errors were 0.86 ± 0.79 degrees (yaw), 0.54 ± 0.48 degrees (roll), and 0.90 ± 0.72 degrees (pitch). The surgical procedures do not differ with respect to their error sizes. Maxilla forward and class II maxilla up with mandible forward are the most precise procedures. Most significant differences were found in the anteroposterior direction, whereby the extent of the surgical movement has no effect on the magnitude of the error. The process of planning with the DMMS followed by surgery is highly accurate and shows error values well below the clinically accepted limit of two millimeters in translation and four degrees in rotation.

Imaging of Facial Reconstruction and Face Transplantation

Pre- and postoperative imaging is increasingly used in plastic and reconstructive surgery for the evaluation of bony and soft tissue anatomy. Imaging plays an important role in preoperative planning. In the postoperative setting, imaging is used for the assessment of surgical positioning, bone healing and fusion, and for the assessment of early or delayed surgical complications. This article will focus on imaging performed for surgical reconstruction of the face, including orthognathic surgery, facial feminization procedures for gender dysphoria, and face transplantation.

Virtual 3D planning and prediction accuracy in two bimaxillary face transplantations in Helsinki

BACKGROUND

The aim of this study was to describe the 3D planning process used in our two composite face transplantations and to analyze the accuracy of a virtual transplantation in predicting the end-result of face transplantation.

METHODS

The study material consists of two bimaxillary composite face transplantations performed in the Helsinki University Hospital in 2016 and 2018. Computed tomography (CT) scans of the recipient and donor were used to define the osteotomy lines and perform the virtual face transplantation and to 3D print customized osteotomy guides for recipient and donor. Differences between cephalometric linear and angular measurements of the virtually simulated and the actual postoperative face transplantation were calculated.

RESULTS

No changes to the planned osteotomy lines were needed during surgery. The differences in skeletal linear and angular measurements of the virtually simulated predictions and the actual postoperative face transplantations of the two patients varied between 0.1-5.6 mm and 0.7°-4°. The postoperative skeletal relationship between maxilla and mandible in both patients were almost identical in comparison to the predictions.

CONCLUSIONS

3D planning is feasible and provides close to accurate bone reconstruction in face transplantation. Preoperative virtual transplantation assists planning and improves the outcome in bimaxillary face transplantation.

Maxillofacial Bony Considerations in Facial Transplantation

Alloplastic facial transplantation has become a new rung on the proverbial reconstructive ladder for severe facial wounds in the past couple of decades. Since the first transfer including bony components in 2006, numerous facial allotransplantations across many countries have been successfully performed, many incorporating multiple bony elements of the face. There are many unique considerations to facial transplantation of bone, however, beyond the considerations of simple soft tissue transfer. Herein, we review the current literature and considerations specific to bony facial transplantation focusing on the pertinent surgical anatomy, preoperative planning needs, intraoperative harvest and inset considerations, and postoperative protocols.

Facial Transplantation

Facial transplantation represents a unique surgical solution for challenging facial injury patterns in which conservative reconstructive techniques fail to provide a satisfactory functional and aesthetic result. With advances in the field of vascularized composite allotransplantation over the past 15 years, more than 40 of these procedures have been performed worldwide with two recent reports of facial re-transplantation. In this article we discuss the multidisciplinary approach that is required for successful transplantation as well as the surgical techniques used and postoperative management. With ongoing research, recent technological innovation, and increased efforts to promote greater generalizability and transparency in this field, patients with these complex injuries will continue to see improvements in their treatment options, and thus quality of life.

Facial Transplantation: Complications, Outcomes, and Long-Term Management Strategies

Within the past two decades, vascularized facial composite allotransplantation has evolved into a viable option in the reconstructive surgeons' armamentarium for patients with extensive facial disfigurements. As it has expanded the frontiers of microsurgical reconstructive techniques, facial transplantation has come to garner widespread interest within both the medical community and the general public. The procedure has established itself as an amalgamation of the forefronts of reconstructive microsurgery, immunology, and transplantation science. Therein too lies its complexity as multifaceted scientific developments are met with ethical and social issues. Both patients and physicians are faced with the everlasting challenges of immunosuppression regimens and their inherent complications, long-term aesthetic and functional considerations, the role of revision procedures, and the inevitable psychosocial implications. This article reflects on the medical and surgical advancements in facial transplantation surgery and highlights anticipated future challenges. It aims to encourage discussion regarding anticipated barriers to current practice and suggest future directions as we transition into the next phase of facial allograft transplantation.

Three-dimensional nasal septum and maxillary changes following rapid maxillary expansion in patients with cleft lip and palate

OBJECTIVES

To determine the three-dimensional changes of the nasal septum (NS), alveolar width, alveolar cleft volume, and maxillary basal bone following rapid maxillary expansion (RME) in consecutive patients with unilateral cleft lip and palate (UCLP).

MATERIALS AND METHODS

A retrospective investigation was conducted based on the analysis of cone-beam computed tomography (CBCT) data of 40 consecutive patients with UCLP (mean age 11.1 ± 2.2 years). Scans were acquired prior to RME (T0) and after removal of the expander (T1) before graft surgery. A three-dimensional analysis of the effects of RME on the nasal septum, alveolar width, alveolar cleft volume, and maxillary basal bone was performed.

RESULTS

No changes in the NS deviation were observed following RME (P > .05). Significant increases of the alveolar transverse dimension were found in the anterior (14.2%; P < .001) and posterior (7.7%; P < .001) regions as well as in the volume of the alveolar cleft (19.6%; P < .001). No changes in the basal bone dimensions and morphology were observed (P > .05).

CONCLUSIONS

Following RME, no changes were observed in the NS and maxillary basal bones of patients with UCLP despite the significant gain in the anterior and posterior alveolar width and the increase of the alveolar cleft defect. Clinicians should be aware that maxillary changes following RME in patients with UCLP are restricted to the dentoalveolar region.

Dental considerations and the role of prosthodontics and maxillofacial prosthetics in facial transplantation

BACKGROUND

Facial transplantation (FT) is a challenging reconstructive endeavor that requires the expertise of a multidisciplinary team. The specific role of maxillofacial prosthodontists has not yet been reported in detail.

METHODS

This review considers the contributions of prosthodontists throughout the FT process, from patient selection and dental evaluation to long-term dental rehabilitation of the transplant patient postoperatively. Moreover, considerations of dental management are evaluated.

RESULTS

In the almost 40 FT reported in the literature, the most consistently documented contribution by prosthodontists is the fabrication of a donor mask to maintain donor integrity. Though infrequently reported, prosthodontists have the potential to plan and perform a variety of dental procedures and follow-up plans.

CONCLUSIONS

When applicable, facial transplant teams are tasked with providing optimal stomatognathic function and dental occlusion to recipients with severe facial disfigurement. The maxillofacial prosthodontist's contribution is crucial to the long-term dental restoration of the edentulous facial transplant candidate, in addition to the fabrication of the donor mask which fulfills the team's ethical responsibilities.

PRACTICAL IMPLICATIONS

Maxillofacial prosthodontists play a pivotal role in facial transplantation, particularly when jaw segments are intended for transplantation.

Achievements and Challenges in Facial Transplantation

: The first facial transplantation in 2005 ushered in a new era in reconstructive surgery, offering new possibilities for the repair of severe disfigurements previously limited by conventional techniques. Advances in allograft design, computerized preoperative planning, surgical technique, and postoperative revisions have helped push the boundaries in this new frontier of vascularized composite allotransplantation. Over the past 12 years, 40 of these procedures have been performed across the world, offering the field the opportunity to reflect on current outcomes. Successes achieved in the brief history of facial transplantation have resulted in a new set of obstacles the field must now overcome. In this review, we aim to highlight the achievements, major challenges, and future directions of this rapidly evolving field.

Computerized Approach to Facial Transplantation: Evolution and Application in 3 Consecutive Face Transplants

Face transplant (FT) candidates present with unique anatomic and functional defects unsuitable for autologous reconstruction, making the accurate design and transplantation of patient-specific allografts particularly challenging. In this case series, we present our computerized surgical planning (CSP) protocol for FT.

Bilateral Sagittal Split Osteotomy: Description of Surgical Technique to Complement the Procedural Cognition Simulation in the Craniofacial Interactive Virtual Assistant-Professional Edition

Operative experience for the contemporary trainee has become exceedingly more challenging in the setting of more stringent hospital regulations. Surgical training is thus shifting toward more self-directed, independent learning to maximize operative opportunities as they become available; yet, this can prove difficult for complex surgeries like craniofacial procedures. The intricate anatomy and fine reconstructive techniques employed cannot be readily depicted onto a two-dimensional page. To address this educational gap, the Craniofacial Interactive Virtual Assistant-Pro Edition (CIVA-Pro) was developed as a web-based surgical simulator to aid learners with conceptualizing the surgical principles utilized in these cases. The current work reviews the Bilateral Sagittal Split Osteotomy module of CIVA-Pro, providing detailed narratives for each chapter with expert commentary on broadened indications and future directions.

Surgery-first approach with 3D customized passive self-ligating brackets and 3D surgical planning: Case report

It is possible to unify three-dimensional customized orthodontic techniques and three-dimensional surgical technology. In this case report, it is introduced a treatment scheme consisting of passive self-ligation customized brackets and virtual surgical planning combined with the orthognathic surgery-first approach in a Class III malocclusion patient. Excellent facial and occlusal outcomes were obtained in a reduced treatment time of five months.

Development and refinement of computer-assisted planning and execution system for use in face-jaw-teeth transplantation to improve skeletal and dento-occlusal outcomes

PURPOSE OF REVIEW

To describe the development and refinement of the computer-assisted planning and execution (CAPE) system for use in face-jaw-teeth transplants (FJTTs).

RECENT FINDINGS

Although successful, some maxillofacial transplants result in suboptimal hybrid occlusion and may require subsequent surgical orthognathic revisions. Unfortunately, the use of traditional dental casts and splints pose several compromising shortcomings in the context of FJTT and hybrid occlusion. Computer-assisted surgery may overcome these challenges. Therefore, the use of computer-assisted orthognathic techniques and functional planning may prevent the need for such revisions and improve facial-skeletal outcomes.

SUMMARY

A comprehensive CAPE system for use in FJTT was developed through a multicenter collaboration and refined using plastic models, live miniature swine surgery, and human cadaver models. The system marries preoperative surgical planning and intraoperative execution by allowing on-table navigation of the donor fragment relative to recipient cranium, and real-time reporting of patient's cephalometric measurements relative to a desired dental-skeletal outcome. FJTTs using live-animal and cadaveric models demonstrate the CAPE system to be accurate in navigation and beneficial in improving hybrid occlusion and other craniofacial outcomes. Future refinement of the CAPE system includes integration of more commonly performed orthognathic/maxillofacial procedures.

The Use of Virtual Surgical Planning in Total Facial Skeletal Reconstruction of Treacher Collins Syndrome: A Case Report

Facial skeletal reconstruction of patients with severe Treacher Collins syndrome (TCS) requires correction of both midface and mandibular deficiencies. Implementing virtual surgical planning can provide an accurate three-dimensional analysis of craniofacial abnormalities, creating calvarial donors that match the anatomy of the desired malar augmentation and facilitating bimaxillary movements, positioning, and fixation in orthognathic surgery. We present a case of an 18-year-old patient with TCS, who underwent staged zygomaticomaxillary reconstruction and double-jaw osteotomy with sliding genioplasty, using computer-assisted surgical planning. Following these operations, the patient achieved not only improved facial harmony but also class I occlusion.

Combining Virtual Surgical Planning, Intraoperative Navigation, and 3-Dimensional Printing in Prosthetic-Based Bilateral Microtia Reconstruction

Reconstructing auricular deformities for bilateral microtia is a demanding challenge especially after failed autologous reconstruction. This case report presents a novel application of virtual surgical planning, computer-assisted design, and intraoperative surgical navigation to preplan and execute placement of custom-tailored silicone auricular prostheses and titanium osseointegrated implants for a bone-anchored hearing aid system in a patient with Treacher Collins syndrome in whom autologous reconstruction had previously failed. Through a collaborative approach between the reconstructive surgeon and anaplastologist, the implementation of advanced digital technologies may offer a superior esthetic and functional outcome to patients with previously failed reconstruction.

Total Face, Eyelids, Ears, Scalp, and Skeletal Subunit Transplant Cadaver Simulation: The Culmination of Aesthetic, Craniofacial, and Microsurgery Principles

BACKGROUND

The application of aesthetic, craniofacial, and microsurgical principles in the execution of face transplantation may improve outcomes. Optimal soft-tissue face transplantation can be achieved by incorporating subunit facial skeletal replacement and subsequent tissue resuspension. The purpose of this study was to establish a reconstructive solution for a full face and scalp burn and to evaluate outcome precision and consistency.

METHODS

Seven mock face transplants (14 cadavers) were completed in the span of 1 year. Components of the vascularized composite allograft included the eyelids, nose, lips, facial muscles, oral mucosa, total scalp, and ears; and skeletal subunits of the zygoma, nasal bone, and genial segment. Virtual surgical planning was used for osteotomy selection, and to evaluate postoperative precision of hard- and soft-tissue elements.

RESULTS

Each transplant experience decreased each subsequent transplant surgical time. Prefabricated cutting guides facilitated a faster dissection of both donor and recipient tissue, requiring minimal alteration to the allograft for proper fixation of bony segments during inset. Regardless of donor-to-recipient size discrepancy, ample soft tissue was available to achieve tension-free allograft inset. Differences between virtual transplant simulation and posttransplant measurements were minimal or insignificant, supporting replicable and precise outcomes.

CONCLUSIONS

This facial transplant model was designed to optimize reconstruction of extensive soft-tissue defects of the craniofacial region representative of electrical, thermal, and chemical burns, by incorporating skeletal subunits within the allograft. The implementation of aesthetic, craniofacial, and microsurgical principles and computer-assisted technology improves surgical precision, decreases operative time, and may optimize function.

Technology and vascularized composite allotransplantation (VCA)-lessons learned from the first bilateral pediatric hand transplant

The reconstructive principle of replacing "like with like" is best met with vascularized composite allotransplantation in which the components of an existing defect are "matched" to the greatest extent possible in a single stage restoration. Hand transplantation is a labor-intensive and time-intensive process and can be conceptualized into distinct phases that include (1) patient selection and preoperative preparation, (2) technical execution of the procedure, and (3) postoperative rehabilitation and follow-up. The advent of technological innovations, such as 3D printing technology, novel implant technology, as well as innovative imaging technology, such as functional magnetic resonance imaging have the potential of favorably affecting all phases of this process, thus contributing to improved outcomes. The use of these technologies in the world's first case of bilateral hand transplantation in a pediatric patient is discussed.

Transformation of Face Transplants: Volumetric and Morphologic Graft Changes Resemble Aging After Facial Allotransplantation

Facial allotransplantation restores normal anatomy to severely disfigured faces. Although >30 such operations performed worldwide have yielded promising short-term results, data on long-term outcomes remain scarce. Three full-face transplant recipients were followed for 40 months. Severe changes in volume and composition of the facial allografts were noted. Data from computed tomography performed 6, 18 and 36 months after transplantation were processed to separate allograft from recipient tissues and further into bone, fat and nonfat soft tissues. Skin and muscle biopsies underwent diagnostic evaluation. All three facial allografts sustained significant volume loss (mean 19.55%) between 6 and 36 months after transplant. Bone and nonfat soft tissue volumes decreased significantly over time (17.22% between months 6 and 18 and 25.56% between months 6 and 36, respectively), whereas fat did not. Histological evaluations showed atrophy of muscle fibers. Volumetric and morphometric changes in facial allografts have not been reported previously. The transformation of facial allografts in this study resembled aging through volume loss but differed substantially from regular aging. These findings have implications for risk-benefit assessment, donor selection and measures counteracting muscle and bone atrophy. Superior long-term outcomes of facial allotransplantation will be crucial to advance toward future clinical routine.

Computer-assisted, Le Fort-based, face-jaw-teeth transplantation: a pilot study on system feasiblity and translational assessment

PURPOSE

Le Fort-based face-jaw-teeth transplantation (FJTT) attempts to marry bone and teeth geometry of size-mismatched face-jaw-teeth segments to restore function and form due to severe mid-facial trauma. Recent development of a computer-assisted planning and execution (CAPE) system for Le Fort-based FJTT in a pre-clinical swine model offers preoperative planning, and intraoperative navigation. This paper addresses the translation of the CAPE system to human anatomy and presents accuracy results.

METHODS

Single-jaw, Le Fort-based FJTTs were performed on plastic models, one swine and one human, and on a human cadaver. Preoperative planning defined the goal placement of the donor's Le Fort-based FJTT segment on the recipient. Patient-specific navigated cutting guides helped achieve planned osteotomies. Intraoperative cutting guide and donor fragment placement were compared with postoperative computed tomography (CT) data and the preoperative plan.

RESULTS

Intraoperative measurement error with respect to postoperative CT was less than 1.25 mm for both mock transplants and 3.59 mm for the human cadaver scenario. Donor fragment placement (as compared to the planned position) was less accurate for the human model test case (2.91 mm) compared with the swine test (2.25 mm) and human cadaver (2.26 mm).

CONCLUSION

The results indicate the viability of the CAPE system for assisting with Le Fort-based FJTT and demonstrate the potential in human surgery. This system offers a new path forward to achieving improved outcomes in Le Fort-based FJTT and can be modified to assist with a variety of other surgeries involving the head, neck, face, jaws and teeth.