The Use of Computer-Aided Design and Manufacturing in Acute Mandibular Trauma Reconstruction

Advances in Three-Dimensional Printing for Craniomaxillofacial Trauma Reconstruction: A Systematic Review

Craniomaxillofacial (CMF) fractures present significant challenges for plastic surgeons due to their intricate nature. Conventional methods such as autologous bone grafts have limitations, necessitating advancements in reconstructive surgery techniques. This study reviewed the use of three-dimensional printing for CMF trauma reconstruction using human studies. A systematic search of PubMed, EMBASE, and Google Scholar was conducted in February 2024 for case reports, case series, and clinical trials related to CMF trauma reconstruction using three-dimensional printing technology. The authors' systematic review included 20 studies and a total of 170 participants with CMF bone defects. In general, the authors observed low bias risk in analyzed case reports and series, serious bias risk in nonrandomized controlled trials, and moderate bias risk in randomized controlled trials. The printed objects included CMF structure model prototypes, patient-specific implants, and other custom surgical devices. Studies reveal successful outcomes, including restored facial symmetry and function, restored orbital occlusion, resolved enophthalmos and diplopia, achieved cosmetically symmetrical lower face reconstruction, and precise fitting of surgical devices, enhancing patient and surgeon comfort. However, complications such as local infection, implant exposure, and persistent diplopia were reported. Three-dimensional printed devices reduced surgery time but increased preparation time and production costs. In-house production options could mitigate these time and cost expenditures. Three-dimensional printing holds potential in CMF trauma reconstruction, addressing both functional and esthetic restoration. Nevertheless, challenges persist in implementing this advanced technology in resource-limited environments.

Streamlining complex mandibular fracture treatment: Integration of virtual surgical planning and short-segment drilling guides

This study aimed to evaluate the feasibility and accuracy of a combined virtual surgical planning (VPS) and short-segment drilling guides (SSDGs) workflow for the treatment of complex mandibular fractures. Consecutive patients with complex mandibular fractures underwent treatment using the VPS and SSDGs workflow from August 2020 to April 2022. Various mandibular landmarks were compared between the preoperative virtual surgical plan and postoperative data, including condylar distance (CoD), mandibular angle width (GoL-GoR), GoMeGo angle (∠GoL-Me-GoR), the difference in mandibular angles between the left and right sides (Δ∠Co-Go-Me), and the difference in length between the left and right mandibular body (ΔGo-Me). Additionally, preoperative preparation time and surgical duration were retrospectively analyzed and compared to conventional surgery. All 14 consecutive patients with complex mandibular fractures achieved successful reduction using the VPS and SSDGs workflow. Three-dimensional comparison revealed a mean deviation distance of 0.91 ± 0.50 mm and a root-mean-square deviation of 1.75 ± 0.47 mm between the preoperative designed mandible model and the postoperative mandible model. The percentage of points with deviation distances less than 2 mm, 1 mm, and 0.5 mm between preoperative and postoperative models were 78.47 ± 8.87 %, 60.02 ± 14.28 %, and 38.64 ± 15.48 %, respectively. There were no significant differences observed in CoD, GoL-GoR, ∠GoL-Me-GoR, Δ∠Co-Go-Me, and ΔGo-Me between preoperative virtual surgical planning and postoperative measurements. Furthermore, no significant differences were found in the injury-to-surgery interval, admission-to-surgery interval, and surgical duration between the workflow and conventional surgery. The combined VPS and SSDGs workflow proved to be an accurate and feasible method for treating complex mandibular fractures. It offers advantages such as minimal preoperative preparation time and the ability to precise transfer screw positions of the pre-bent reconstruction plate during surgery. This approach is particularly suitable for managing complex mandibular fractures.

Can a Point-of-Care 3D Printing Workflow Produce Accurate and Successful Results for Craniomaxillofacial Trauma?

BACKGROUND

Computer-aided design and manufacturing (CAD/CAM) is having a profound impact on craniomaxillofacial surgery, and point-of-care (POC) solutions for repairing facial trauma are starting to emerge.

PURPOSE

The purpose of this study was to demonstrate the success and accuracy of a POC 3D printing workflow for craniomaxillofacial trauma.

STUDY DESIGN, SETTING, SAMPLE

A retrospective cohort study was undertaken to analyze subjects presenting to a level 1 trauma center after sustaining facial trauma and were then treated using the POC 3D printing workflow. Subjects were excluded if they were not treated with the POC 3D printing workflow, were lost to follow-up, or if clinical data were incomplete.

PREDICTOR VARIABLE

Predictor variables included the cause of trauma (mechanism), location of the mandibular fracture, type of fracture, mandibular severity score, and repair error (ie, root mean square error (RMSE) value for planned vs actual outcome).

MAIN OUTCOME VARIABLE(S)

The primary outcome variables were case success and case error. Success was defined as clinical and radiographic evidence of bony stability at 3 months. Case accuracy was calculated overlaying preoperative plan data to postoperative data generating a numerical value (RMSE value, mm).

COVARIATES

Covariates included age (years), gender (male/female), surgery time (mins), and CAD/CAM time (preoperative).

ANALYSES

Descriptive statistics were calculated for each variable. Dependence between rates or counts was established using the Wilcoxon rank sum or Fisher's exact test. Linear regression model was computed to discern how predictor variables influence RMSE. A P value < .05 was considered statistically significant.

RESULTS

The sample included 27 subjects (19 male/8 female). The average age of all subjects was 46.4 ± 18.0 years. Common mechanisms of injury were assault (33%) and self-inflicted gunshots (SIGSW; 30%), and the average severity score for mandible injury was (13.5 ± 3.3). Ninety-three percent of cases were deemed successful. The average repair accuracy (RMSE value) was 3.4 ± 1.8 mm. A linear regression model indicated those injured by a fall (β-coefficient 1.99; P = .010), motor vehicle collision (β-coefficient 1.49; P = .043), or SIGSW (β-coefficient 2.82; P < .001) correlated with RMSE.

CONCLUSION AND RELEVANCE

In-house CAD/CAM technologies can be utilized at the POC to repair complex facial trauma accurately and successfully.

Computer-assisted preoperative planning of bone fracture fixation surgery: A state-of-the-art review

Background: Bone fracture fixation surgery is one of the most commonly performed surgical procedures in the orthopedic field. However, fracture healing complications occur frequently, and the choice of the most optimal surgical approach often remains challenging. In the last years, computational tools have been developed with the aim to assist preoperative planning procedures of bone fracture fixation surgery. Objectives: The aims of this review are 1) to provide a comprehensive overview of the state-of-the-art in computer-assisted preoperative planning of bone fracture fixation surgery, 2) to assess the clinical feasibility of the existing virtual planning approaches, and 3) to assess their clinical efficacy in terms of clinical outcomes as compared to conventional planning methods. Methods: A literature search was performed in the MEDLINE-PubMed, Ovid-EMBASE, Ovid-EMCARE, Web of Science, and Cochrane libraries to identify articles reporting on the clinical use of computer-assisted preoperative planning of bone fracture fixation. Results: 79 articles were included to provide an overview of the state-of-the art in virtual planning. While patient-specific geometrical model construction, virtual bone fracture reduction, and virtual fixation planning are routinely applied in virtual planning, biomechanical analysis is rarely included in the planning framework. 21 of the included studies were used to assess the feasibility and efficacy of computer-assisted planning methods. The reported total mean planning duration ranged from 22 to 258 min in different studies. Computer-assisted planning resulted in reduced operation time (Standardized Mean Difference (SMD): -2.19; 95% Confidence Interval (CI): -2.87, -1.50), less blood loss (SMD: -1.99; 95% CI: -2.75, -1.24), decreased frequency of fluoroscopy (SMD: -2.18; 95% CI: -2.74, -1.61), shortened fracture healing times (SMD: -0.51; 95% CI: -0.97, -0.05) and less postoperative complications (Risk Ratio (RR): 0.64, 95% CI: 0.46, 0.90). No significant differences were found in hospitalization duration. Some studies reported improvements in reduction quality and functional outcomes but these results were not pooled for meta-analysis, since the reported outcome measures were too heterogeneous. Conclusion: Current computer-assisted planning approaches are feasible to be used in clinical practice and have been shown to improve clinical outcomes. Including biomechanical analysis into the framework has the potential to further improve clinical outcome.

Same-Admission Microvascular Maxillofacial Ballistic Trauma Reconstruction Using Virtual Surgical Planning: A Case Series and Systematic Review

Study Design

Retrospective case series; systematic review.

Objective

It is unknown whether the use of virtual surgical planning (VSP) to facilitate same-admission microsurgical reconstruction of the mandible following acute maxillofacial ballistic trauma (MBT) is sufficient to achieve definitive reconstruction and functional occlusion.

Methods

A single-center retrospective analysis was conducted for patients who underwent microsurgical reconstruction of the mandible using VSP after acute MBT. The PubMed/MEDLINE, Embase, ScienceDirect, and Scopus databases were systematically reviewed using blinded screening. Studies were evaluated via thematic analysis.

Results

Five patients were treated by same-admission and microsurgical reconstruction of the mandible using VSP. We observed an average of 16.4 ± 9.1 days between initial presentation and reconstruction, an average length of stay of 51.6 ± 17.9 days, 6.2 ± 2.8 operations, and 1.6 ± 0.9 free flaps per patient. Four types and 8 total flaps were employed, most commonly the anterior lateral thigh flap (37.5%). Care yielded complete flap survival. Each patient experienced at least 1 minor complication. All patients achieved centric occlusion, oral nutrition, and an approximation of their baseline facial aesthetic. Follow up was 191.0 ± 183.9 weeks. Systematic review produced 8 articles that adhered to inclusion criteria. Consensus themes in the literature were found for clinical goal and function of VSP when practicing MBT reconstruction, yet disagreement was found surrounding optimal treatment timeline.

Conclusions

Same-admission microsurgical reconstruction after MBT is safe and effective to re-establish mandibular form and function. VSP did not delay reconstruction, given the need for preparation prior to definitive reconstruction.

3D Printing and Virtual Surgical Planning in Oral and Maxillofacial Surgery

Compared to traditional manufacturing methods, additive manufacturing and 3D printing stand out in their ability to rapidly fabricate complex structures and precise geometries. The growing need for products with different designs, purposes and materials led to the development of 3D printing, serving as a driving force for the 4th industrial revolution and digitization of manufacturing. 3D printing has had a global impact on healthcare, with patient-customized implants now replacing generic implantable medical devices. This revolution has had a particularly significant impact on oral and maxillofacial surgery, where surgeons rely on precision medicine in everyday practice. Trauma, orthognathic surgery and total joint replacement therapy represent several examples of treatments improved by 3D technologies. The widespread and rapid implementation of 3D technologies in clinical settings has led to the development of point-of-care treatment facilities with in-house infrastructure, enabling surgical teams to participate in the 3D design and manufacturing of devices. 3D technologies have had a tremendous impact on clinical outcomes and on the way clinicians approach treatment planning. The current review offers our perspective on the implementation of 3D-based technologies in the field of oral and maxillofacial surgery, while indicating major clinical applications. Moreover, the current report outlines the 3D printing point-of-care concept in the field of oral and maxillofacial surgery.

Short-Segment Drilling Guides for the Management Comminuted Mandibular Fractures

ABSTRACT

Treatment of a severely comminuted mandibular fracture is challenging. This technical note describes a novel office-based workflow, combining virtual surgery planning with short-segment drilling guides. The authors reduced the comminuted mandibular fractures via virtual surgery planning. Then, the reconstructed mandible model was printed using an in-house 3D printer. Next, the reconstruction plate was preformed according to the shape of the mandibular model surface, and the position of the screw hole in the mandibular surface was determined. Finally, hand-made short-segment drilling guides for screw position transfer were fabricated with temporary resin. During the operation, the authors reset the guides for the drill to make screw holes as planned. After the hole was drilled, the pre-bent plate was applied to the mandible. The fracture was expected to be reduced, when tightening the screws. In our workflow, by using short and simple operative procedures, the authors were able to achieve precise reduction and reduce the operation time.

Point-of-care computer-assisted design and manufacturing technology and its utility in post-traumatic mandibular reconstruction: An Australian public hospital experience

Application of load-bearing osteosynthesis plates is the current gold-standard management for complex mandibular fractures. Traditionally, this has required a transcutaneous submandibular approach, carrying with it the risk of damage to the facial nerve and obvious extraoral scarring. The existing literature describes the use of computer-assisted design and manufacturing technology through external vendors to aid transoral mandibular reconstruction. However, the reliance on third-party manufacturers comes with significant drawbacks, notably increased financial costs and manufacturing delays. We describe our experience in using point-of-care three-dimensional-printed surgical models to aid with the application of mandibular reconstruction plates. Utilising a virtual three-dimensional reconstruction of the patient’s preoperative computed tomography facial bones, we fabricate a custom model of the patient’s mandible with the department’s in-house three-dimensional printer. Stock plates are subsequently pre-bent and adapted to the three-dimensional model, with plate and screw position marked and screw lengths measured with callipers. By using a custom three-dimensional-printed surgical model to pre-contour the plates, we are able to position stock reconstruction plates via a transoral approach. Moreover, our unit’s utilisation of in-house computer-assisted design and manufacturing software and hardware allows us deliver a same-day turnaround for both surgical planning and performing the operation. Patient-specific surgical planning guides can facilitate the safe and efficient transoral application of mandibular reconstruction plates. Moreover, the use of point-of-care computer-assisted design and manufacturing technology ensures timely and cost-effective manufacturing of the necessary biomodel.

Advanced Three-Dimensional Technologies in Craniofacial Reconstruction

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Describe the evolution of three-dimensional computer-aided reconstruction and its current applications in craniofacial surgery. 2. Recapitulate virtual surgical planning, or computer-assisted surgical simulation, workflow in craniofacial surgery. 3. Summarize the principles of computer-aided design techniques, such as mirror-imaging and postoperative verification of results. 4. Report the capabilities of computer-aided manufacturing, such as rapid prototyping of three-dimensional models and patient-specific custom implants. 5. Evaluate the advantages and disadvantages of using three-dimensional technology in craniofacial surgery. 6. Critique evidence on advanced three-dimensional technology in craniofacial surgery and identify opportunities for future investigation.

SUMMARY

Increasingly used in craniofacial surgery, virtual surgical planning is applied to analyze and simulate surgical interventions. Computer-aided design and manufacturing generates models, cutting guides, and custom implants for use in craniofacial surgery. Three-dimensional computer-aided reconstruction may improve results, increase safety, enhance efficiency, augment surgical education, and aid surgeons' ability to execute complex craniofacial operations. Subtopics include image analysis, surgical planning, virtual simulation, custom guides, model or implant generation, and verification of results. Clinical settings for the use of modern three-dimensional technologies include acquired and congenital conditions in both the acute and the elective settings. The aim of these techniques is to achieve superior functional and aesthetic outcomes compared to conventional surgery. Surgeons should understand this evolving technology, its indications, limitations, and future direction to use it optimally for patient care. This article summarizes advanced three-dimensional techniques in craniofacial surgery with cases highlighting clinical concepts.

Computer-Aided Design and Manufacturing versus Conventional Surgical Planning for Head and Neck Reconstruction: A Systematic Review and Meta-Analysis

BACKGROUND

Virtual surgical planning and computer-aided design/computer-aided manufacturing (CAD/CAM) for complex head and neck reconstruction has a number of cited advantages over conventional surgical planning, such as increased operative efficiency, fewer complications, improved osseous flap union, immediate osseointegrated dental implant placement, and superior functional and aesthetic outcomes. The authors performed a systematic review and meta-analysis of the available evidence on CAD/CAM maxillofacial reconstruction with the primary purpose of determining which approach is more efficacious.

METHODS

In accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a PubMed and Embase database search was performed to identify English-language, human-subject studies of CAD/CAM-assisted head and neck reconstruction. All comparative studies were included in a meta-analysis to identify differences in operative time, ischemia time, surgical-site occurrence, microvascular complication, and partial or total flap loss between the two groups. All included studies (comparative and noncomparative) were used in the systematic review, summarizing the various flap characteristics, technical nuances, and functional and aesthetic outcomes.

RESULTS

Twelve articles were included in the meta-analysis, representing 277 patients in the CAD/CAM group and 419 patients in the conventional group. CAD/CAM was associated with 65.3 fewer minutes of operating room time (95 percent CI, -72.7 to -57.9 minutes; p < 0.0001) and 34.8 fewer minutes of ischemia time (95 percent CI, -38 to -31.5 minutes; p < 0.0001). There were no significant differences in surgical-site occurrence, nonunion, flap loss, microvascular complications, or hardware-related complications.

CONCLUSIONS

CAD/CAM is associated with shorter operating room and ischemia times. There are no significant differences in flap or hardware-related complications between CAD/CAM and conventional surgical planning.

Evaluation of in-house, haptic assisted surgical planning for virtual reduction of complex mandibular fractures

Purpose

The management of complex mandible fractures, i.e. severely comminuted or fractures of edentulous/atrophic mandibles, can be challenging. This is due to the three-dimensional loss of bone, which limits the possibility for accurate anatomic reduction. Virtual surgery planning (VSP) can provide improved accuracy and shorter operating times, but is often not employed for trauma cases because of time constraints and complex user interfaces limited to two-dimensional interaction with three-dimensional data.

Methods

In this study, we evaluate the accuracy, precision, and time efficiency of the haptic assisted surgery planning system (HASP), an in-house VSP system that supports stereo graphics, six degrees-of-freedom input, and haptics to improve the surgical planning. Three operators performed planning in HASP on computed tomography (CT) and cone beam computed tomography (CBCT) images of a plastic skull model and on twelve retrospective cases with complex mandible fractures.

Results

The results show an accuracy and reproducibility of less than 2 mm when using HASP for virtual fracture reduction, with an average planning time of 15 min including time for segmentation in the software BoneSplit.

Conclusion

This study presents an in-house haptic assisted planning tool for cranio-maxillofacial surgery with high usability that can be used for preoperative planning and evaluation of complex mandible fractures.

Scoping Zygomaticomaxillary Complex Fractures With the Eyes of Virtual Reality: Operative Protocol and Proposal of a Modernized Classification

INTRODUCTION

Fractures of the zygomaticomaxillary complex (ZMC) represent an extremely heterogeneous group of injuries to the midfacial skeleton. Traditionally, the diagnosis of such fractures was based on 2-dimensional radiograms and, more recently, on volumetric computed tomography (CT) scans, while the treatment was exclusively based on the surgeon's experience. Many classification attempts have been made in the past, but no paper has taken into account the importance of virtual surgical planning (VSP) in proving a modernized classification. The authors propose a classification based on the use of VSP which can guide the surgeon to identify the optimal reduction method and reproduce it in the operating room through the use of navigation.

METHODS

Patients with ZMC fractures were collected to create a study model. The VSP was used to generate 3-dimensional models of fractures. Fractured segments were duplicated and digitally put in the optimal reduction position. Repositioned fragments were overlapped to their original preoperative counterparts and exported to the surgical navigator to be navigated. Planned virtual reduction was overlaid to postoperative CT scan to assess the accuracy of reduction, explored using color maps and the calculation of root mean square error.

RESULTS

For all patients, the application of VSP was successfully accomplished. High accuracy was confirmed between the planned virtual reduction and the postoperative CT scan. A 5-item classification based on VSP is proposed. All patients were included in the presented subclasses.

CONCLUSIONS

The adoption of virtual planning in ZMC fractures allows for an improved study of the displacement of the fracture and might indicate to the surgeons the required maneuvers to achieve optimal reduction. The presented proposal of classification might be an aid to simplify the choice of the most appropriate reduction method and might provide a deeper insight into the morphologic characteristics of fractures.

Facial Reconstruction: A Systematic Review of Current Image Acquisition and Processing Techniques

Introduction: Plastic and reconstructive surgery is based on a culmination of technological advances, diverse techniques, creative adaptations and strategic planning. 3D imaging is a modality that encompasses several of these criteria while encouraging the others. Imaging techniques used in facial imaging come in many different modalities and sub-modalities which is imperative for such a complex area of the body; there is a clear clinical need for hyper-specialized practice. However, with this complexity comes variability and thus there will always be an element of bias in the choices made for imaging techniques. Aims and Objectives: The aim of this review is to systematically analyse the imaging techniques used in facial reconstruction and produce a comprehensive summary and comparison of imaging techniques currently available, including both traditional and novel methods. Methods: The systematic search was performed on EMBASE, PubMed, Scopus, Web of Science and Cochrane reviews using keywords such as "image technique/acquisition/processing," "3-Dimensional," "Facial," and "Reconstruction." The PRISMA guidelines were used to carry out the systematic review. Studies were then subsequently collected and collated; followed by a screening and exclusion process with a final full-text review for further clarification in regard to the selection criteria. A risk of bias assessment was also carried out on each study systematically using the respective tool in relation to the study in question. Results: From the initial 6,147 studies, 75 were deemed to fulfill all selection criteria and selected for meta-analysis. The majority of papers involved the use of computer tomography, though the use of magnetic resonance and handheld scanners using sonography have become more common in the field. The studies ranged in patient population, clinical indication. Seminal papers were highlighted within the group of papers for further analysis. Conclusions: There are clearly many factors that affect the choice of image acquisition techniques and their potential at being ideal for a given role. Ultimately the surgical team's choice will guide much of the decision, but it is crucial to be aware of not just the diagnostic ability of such modalities, but their treatment possibilities as well.

Digital workflow for treating comminuted anterior mandibular fracture - A technical note

Comminuted mandibular fracture poses a surgical challenge. Extensive comminution and absence of reference adds complexity particularly in anterior region. In this technical note, we describe a novel application of virtual surgical planning combined with 3D printing which grants precise anatomic reduction in such cases. Computed Tomography data (mandible) of another patient of same age and sex was utilized to create reference model by virtual surgical planning. Virtually created model was 3D printed and utilized for precontouring the reconstruction plate which assisted in achieving satisfactory outcome.

Utilization of Virtual Surgical Planning for Surgical Splint-Assisted Comminuted Maxillomandibular Fracture Reduction and/or Fixation

Study Design

This article was a technical note.

Objective

To demonstrate the utilization of virtual surgical planning for surgical splint (VSPSS) fabrication. The VSPSS was used as an intraoperative assisting and guiding tool for reduction and/or fixation of treatment of comminuted maxillomandibular fractures.

Methods

The presented technical note showed the fabrication process that began with data acquisition and presurgical planning using virtual surgical planning (VSP). The VSPSS was designed and fabricated after the fractures were reduced digitally in VSP. In the operating room, the VSPSS was seated to guide reduction and/or allow satisfactory fixation in three different situations.

Results

Postoperative radiographs showed an acceptable reduction of the fractures. All patients had stable and repeatable occlusion postoperatively.

Conclusions

The VSPSS is a feasible tool for surgeons to assist in the comminuted maxillomandibular fracture management, decrease operating time, and improve fracture stability.

Trends in Utilization of Virtual Surgical Planning in Pediatric Craniofacial Surgery

INTRODUCTION

While the use of virtual surgical planning (VSP) has been well described in the adult craniofacial literature, there has been little written about pediatric uses or trends. The purpose of this study is to evaluate the evolving utilization of VSP for pediatric craniofacial procedures.

METHODS

The authors' prospective institutional review board-approved craniofacial registry was queried for index craniofacial procedures from January 2011 through December 2018. Data was collected regarding utilization of traditional surgical planning versus VSP, as well as the extent of VSP's influence on the operative procedure. These data were analyzed for trends over time and compared using appropriate statistics.

RESULTS

During the study period, a total of 1131 index craniofacial cases were performed, of which 160 cases (14.1%) utilized VSP. Utilization of VSP collectively increased over time, from 2.0% in 2011 to 18.6% in 2018 (P < 0.001). Utilization rates of VSP varied across procedures from 0% of craniosynostosis cases and fronto-orbital advancement cases to 67% of osteocutaneous free tissue transfers (P < 0.001). The most profound contributor to increase in VSP utilization was orthognathic surgery, utilized in 0% of orthognathic procedures in 2011 to 68.3% of orthognathic procedures in 2018 (P < 0.001).

CONCLUSIONS

Utilization of virtual surgical planning for pediatric craniofacial procedures is increasing, especially for complex orthognathic procedures and osteocutaneous free tissue transfers. Utilization patterns of individual components of the VSP system demonstrate unique footprints across the spectrum of craniofacial procedures, which reinforces the specific and variable benefits of this workflow for treating pediatric craniofacial disorders.