Plastic Surgery Applications Using Three-Dimensional Planning and Computer-Assisted Design and Manufacturing:

3D Technology for Autologous Breast Reconstruction: Increased Aesthetic Outcomes and Quality of Life Utilizing Patient-Specific Templates

BACKGROUND

In autologous breast reconstruction accomplishing aesthetically pleasing outcomes represents an integral challenge. Three-dimensional (3D) technology may aid in accurate flap shaping and subsequent breast appearance.

OBJECTIVES

The aim of this study was to evaluate the applicability of 3-dimensional technology for surgical planning and its influence on outcomes for breast reconstruction.

METHODS

Outcomes of 50 female patients who underwent deep epigastric artery perforator flap breast reconstruction were analyzed. The patient population was divided into 2 study groups (with 3D technology vs without), including 25 patients each. Based on individual 3D scans and simulations, patient-specific templates were utilized intraoperatively in the 3D group. Quality of life assessment and aesthetic evaluations of breast appearance were statistically evaluated and compared.

RESULTS

Various scales of the BREAST-Q showed statistically significantly better values in the 3D group (P < .05). Concerning breast appearance, patients with 3D technology rated their breast shape and projection statistically significantly higher compared to the control group (P < .05). In addition, blinded ratings of external plastic surgeons were statistically significantly higher related to shape, symmetry, and projection of breasts with 3D technology (P < .05). All patients treated with 3D technology-assisted breast reconstruction strongly recommended this approach.

CONCLUSIONS

Patient-specific templates represent a practical method for facilitating personalized flap planning and shaping. Results demonstrated that 3D technology significantly enhances breast reconstruction outcomes concerning aesthetics and postoperative quality of life.

LEVEL OF EVIDENCE: 3 (THERAPEUTIC)

Virtual surgical planning in orthognathic surgery: A prospective evaluation of postoperative accuracy

OBJECTIVES

The development of 3D computer-assisted technologies over the past years has led to vast improvements in orthognathic surgery. The aim of the present study was to evaluate differences in maxillary position between 3D virtual surgical planning (VSP) and surgical results.

MATERIALS AND METHODS

We assessed data from 25 patients who underwent bimaxillary non-segmented orthognathic surgery with 3D VSP. Each patient underwent a postoperative CT scan within 40 days after surgery. We compared the STL (Standard Triangulation Language) file from the VSP with that obtained from the postoperative CT.

RESULTS

According to our comparative analysis, the postoperative and VSP 3D models did not statistically differ. The Lin concordance correlation coefficient was always >0.95 for each landmark, but in 21 patients (84 % of the sample) we identified at least one point with a difference of more than 1.5 mm between the postoperative and VSP 3D model on at least one axis. The most frequently observed differences corresponded to sagittal translation and pitch rotation.

CONCLUSIONS

An intraoperative clinical and aesthetic evaluation of the consequences of bone movements on patient face is strongly recommended, also when we use VSP because we may have clinically significant differences from the planning.

Three-Dimensional Planning for Vascularized Bone Grafts: Implementation and Surgical Application for Complex Bone Reconstruction in the Hand and Forearm

Background/Objectives: Vascularized bone grafts have been successfully established for complex bone defects. The integration of three-dimensional (3D) simulation and printing technology may aid in more precise surgical planning and intraoperative bone shaping. The purpose of the present study was to describe the implementation and surgical application of this innovative technology for bone reconstruction. Methods: This prospective pilot study was conducted between June 2019 and June 2024. For this evaluation, patients who received vascularized bone reconstruction assisted with 3D technology were included. For reconstruction, the free medial femoral condyle (MFC) flap was used as the vascularized bone graft. Patient-specific 3D-printed templates, based on individual 3D simulations according to defect characteristics, were used for surgical planning, including flap elevation, shaping and inset. Results: A total of six patients (five male) with an average age of 39 years (range 19-62 years) and a mean follow-up time of 15 months (range 5-24 months) were analysed. The indications were as follows: avascular necrosis of the carpal bones, a metacarpal defect after tumor resection and pseudoarthrosis after a fractured ulna. Three patients received an osteochondral and three patients received a cortico-cancellous MFC flap. Conclusions: Our evaluation of clinical application revealed enhanced preoperative planning as well as intraoperative performance. Although the implementation for this technology is challenging, the new insights gained in planning and surgical guidance have led us to incorporate this technology into our standard routine.

Application and exploration of interprofessional education in the teaching of plastic and reconstructive surgery: a narrative review

The growing discussion on "interdisciplinary integration" brings attention to the "interprofessional education" (IPE) in the field of plastic surgery. IPE not only improves the precision and effectiveness of plastic and reconstructive surgery but also plays an important role in personalized treatment. Whereas, the implementation of IPE in plastic and reconstructive surgery field faces huge difficulties such as technology combination, standard making, and lacking of qualified talents. This article individually summarizes the latest developments in the integration of plastic and reconstructive surgery with engineering, basic science, and human science. It looks forward to the future practice and innovation of IPE in the field of plastic and reconstructive surgery, analyzes the challenges in cultivating innovative professional talents, and proposes methods to overcome these difficulties in a way that invites further discussion.

Modification of Sagittal Split Osteotomy in Class II Asymmetry: Optimizing Bone Contact between Proximal and Distal Segments

BACKGROUND

Computer-assisted surgical simulation (CASS) allows more precise orthognathic surgery. However, few studies have evaluated associations between CASS-designed bilateral sagittal split osteotomy (SSO) and bone contact surface in class II mandibular asymmetry. This study aims to evaluate the effects of using computer-assisted simulation and design modification of SSO to improve bony contact in skeletal class II asymmetry.

METHODS

This retrospective analysis reviewed 28 patients with class II asymmetry who underwent orthognathic surgery, including 15 with modified SSO (group CS) and 13 with conventional SSO (group C). Modified SSO was designed under CASS. Operative characteristics, postoperative outcomes, and complications were collected and compared between the two groups.

RESULTS

Bony contact was found at the distal end of the proximal segment in all group CS patients, while bone gap was noted in all group C patients ( P < 0.05). Moreover, bone graft was used in four group C patients but was not used in all cases in group CS patients ( P < 0.05). A trend toward lower operative time or perioperative bleeding was noted in group CS, but without statistical significance. After 1-year follow-up, inferior alveolar nerve disturbances were noted in two group CS patients and one group C patient. Palpable bone gap with uneven jaw line was noted in two group C patients 1 year after surgery and one patient received fat graft treatment.

CONCLUSION

The simulation-based SSO modification provides appropriate contact surface and eliminates the bone gap between proximal and distal segments in class II asymmetry.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Changes in Nasal Tip Aesthetics Over Time Following Asian Tip Plasty

OBJECTIVES

This study aimed to evaluate the sequential postoperative changes in tip aesthetics, by evaluating the aesthetic performance of the septal extension graft with or without tip grafting.

METHODS

A total of 62 patients who underwent rhinoplasty with tip plasty were included. Using a three-dimensional scanner, we measured anthropometric aesthetic features of the nasal tip, including tip height, tip width, nasolabial angle, and columellar lobular angle. Preoperative and 1-month and 12-month postoperative anthropometric parameters were compared. The patients were grouped according to surgical techniques (i.e., septal extension only and septal extension plus tip grafting groups) and subtype of tip graft.

RESULTS

The 1-month postoperative values of all four aesthetic features were significantly increased compared with the preoperative values. The tip height, tip width, and nasolabial angle at 12 months were significantly decreased compared with 1 month post-operation values, whereas the tip height and width were still greater than the preoperative values. No difference was found between 1 and 12 month values of columellar lobular angle. There were no differences in the degree of decrease in tip height, tip width, nasolabial angle, and columellar lobular angle between the septal extension graft only and septal extension graft plus tip graft groups. There were no differences in the tip graft by subtypes, single- and multi-layer tip grafts.

CONCLUSIONS

Increased tip height, tip width, and widened nasolabial angle gained immediately after septal extension grafting surgery gradually decreased over the year regardless of addition of tip graft or tip grafting methods.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:678-683, 2024.

Efficacy and feasibility of a forehead flap surgical guide for nasal reconstruction

For successful nasal reconstruction using a forehead flap, three-dimensional (3D) nasal defects need to be translated into a two-dimensional (2D) forehead surface. For this study, a patient-specific 3D-printed forehead flap guide that could precisely translate a virtually simulated nasal shape into a 2D flap template was developed. The study aimed to evaluate the feasibility and efficacy of a 3D-printed forehead flap guide for nasal reconstructions. The 3D nasal surface was scanned using a 3D camera, and a 'digital clay' process was performed to correct the nasal deformity. The 3D morphology was flattened into a 2D forehead flap guide. The guide was 3D-printed and used for the forehead flap design. Photographic records were used to conduct anthropometric and aesthetic evaluations. Between October 2016 and August 2020, forehead flaps were performed using the forehead flap guide (guide group) and traditional templating method (control group) in 16 and 15 patients, respectively. The alar shape was more symmetric in the guide group than in the control group, with smaller right-to-left differences in alar width (p = 0.01) and height (p = 0.05). Regarding aesthetic evaluations, nose contour (p = 0.02) and nasal symmetry (p = 0.033) were better in the guide group than in the control group. The mean operative time was significantly shorter (91.9 ± 10.7 min) in the guide group than in the control group (116.4 ± 13.6 min) (p = 0.001). Our findings suggest that a 3D-printed forehead flap surgical guide can be effectively used in nasal reconstruction to reduce operative time and improve aesthetic outcomes.

Synergy between artificial intelligence and precision medicine for computer-assisted oral and maxillofacial surgical planning

OBJECTIVES

The aim of this review was to investigate the application of artificial intelligence (AI) in maxillofacial computer-assisted surgical planning (CASP) workflows with the discussion of limitations and possible future directions.

MATERIALS AND METHODS

An in-depth search of the literature was undertaken to review articles concerned with the application of AI for segmentation, multimodal image registration, virtual surgical planning (VSP), and three-dimensional (3D) printing steps of the maxillofacial CASP workflows.

RESULTS

The existing AI models were trained to address individual steps of CASP, and no single intelligent workflow was found encompassing all steps of the planning process. Segmentation of dentomaxillofacial tissue from computed tomography (CT)/cone-beam CT imaging was the most commonly explored area which could be applicable in a clinical setting. Nevertheless, a lack of generalizability was the main issue, as the majority of models were trained with the data derived from a single device and imaging protocol which might not offer similar performance when considering other devices. In relation to registration, VSP and 3D printing, the presence of inadequate heterogeneous data limits the automatization of these tasks.

CONCLUSION

The synergy between AI and CASP workflows has the potential to improve the planning precision and efficacy. However, there is a need for future studies with big data before the emergent technology finds application in a real clinical setting.

CLINICAL RELEVANCE

The implementation of AI models in maxillofacial CASP workflows could minimize a surgeon's workload and increase efficiency and consistency of the planning process, meanwhile enhancing the patient-specific predictability.

The Feasibility of Computer Simulations and 3-Dimensional-Printed Resection Guides for Skin Cancer Resection

The surgical resection margin in skin cancer is traditionally determined by the lesion's surface boundary without 3-dimensional information. Computed tomography (CT) can offer additional information, such as tumor invasion and the exact cancer extent. This study aimed to demonstrate the clinical application of and to evaluate the safety and accuracy of resection guides for skin cancer treatment. This prospective randomized comparison of skin cancer resection with (guide group; n=34) or without (control group; n=28) resection guide use was conducted between February 2020 and November 2021. Patients with squamous cell carcinoma or basal cell carcinoma were included. In the guide group, based on CT images, the surgical margin was defined, and a 3-dimensional-printed resection guide was fabricated. The intraoperative frozen biopsy results and distance from tumor boundary to resection margin were measured. The margin involvement rates were 8.8% and 17.9% in the guide and control groups, respectively. The margin involvement rate was nonsignificantly higher in the control group as compared with the guide group ( P =0.393). The margin distances of squamous cell carcinoma were 2.3±0.8 and 3.4±1.6 mm ( P =0.01) and those of basal cell carcinoma were 2.8±1.0 and 4.7±3.2 mm in the guide and control groups, respectively ( P =0.015). Margin distance was significantly lower in the guide group than the control group. The resection guide demonstrated similar safety to traditional surgical excision but enabled the minimal removal of normal tissue by precisely estimating the tumor border on CT scans.

Establishing a Point-of-Care Virtual Planning and 3D Printing Program

Virtual surgical planning (VSP) and three-dimensional (3D) printing have become a standard of care at our institution, transforming the surgical care of complex patients. Patient-specific, anatomic models and surgical guides are clinically used to improve multidisciplinary communication, presurgical planning, intraoperative guidance, and the patient informed consent. Recent innovations have allowed both VSP and 3D printing to become more accessible to various sized hospital systems. Insourcing such work has several advantages including quicker turnaround times and increased innovation through collaborative multidisciplinary teams. Centralizing 3D printing programs at the point-of-care provides a greater cost-efficient investment for institutions. The following article will detail capital equipment needs, institutional structure, operational personnel, and other considerations necessary in the establishment of a POC manufacturing program.

Virtual Planning and 3D Printing in Contemporary Orthognathic Surgery

Orthognathic surgery is a powerful tool to improve facial balance, form, and function. Virtual planning and three-dimensional printing has improved our ability to visualize complex anatomy, consider various iterations and execute complex movements, and create accurate splints, plates, and cutting guides. This article will outline the distinct advantages of the use of virtual surgical planning over traditional planning, and it will explore the utility of computer-aided design and technology within contemporary orthognathic surgery, including its expanded applications and limitations.

Mandibular Distraction Osteogenesis in Robin Sequence Using Three-Dimensional Analysis and Planning

SUMMARY

The optimal management of patients with Robin sequence may include neonatal mandibular distraction osteogenesis, which has been used to achieve excellent functional and aesthetic outcomes in appropriate patients. This article and video vignette depict the treatment of micrognathia and airway obstruction secondary to Robin sequence, demonstrating the planning and surgical approach of the senior author (D.M.S.) using mandibular distraction osteogenesis.

The usefulness of patient-specific 3D nasal silicone implant using 3D design and order form

PURPOSE

The need for customized implants has continuously increased, but patient-specific silicone implants are not yet commonly used in the plastic surgery market. We sought to validate the effectiveness of a 3D customized nasal implant design in terms of design and lead time compared with a manually customized implant by a surgeon.

MATERIALS AND METHODS

Based on the computed tomography (CT) findings of 15 patients who planned rhinoplasty, a surgeon wrote order forms reflecting the surgical plan and subsequently designed implants manually using epoxy on a 3D printed skull. Separately, engineers analyzed the CT findings and designed 3D implants based on the order forms.

RESULTS

Epoxy designs were 3D-scanned, converted into a stereolithography format and compared with 3D implant designs to assess which method had a smaller margin of error as per the preoperative order form. Moreover, the lead time in all steps are compared. Nasion thickness, tip thickness, glabella starting point, glabella width, radix width, and total volume were comparatively analyzed. In all parameters, the error rate of the 3D design is relatively lower than that of the epoxy design. The former also had a lower total volume and a faster manufacturing time.

CONCLUSION

With novel 3D customized nasal implants, the limitations of ready-made silicone implants are addressed, and it is now possible to preoperatively design implants more accurately, quickly, and conveniently.

Clinical Applications of Meshed Multilayered Anatomical Models by Low-Cost Three-Dimensional Printer

SUMMARY

In recent years, even low-cost fused deposition modeling-type three-dimensional printers can be used to create a three-dimensional model with few errors. The authors devised a method to create a three-dimensional multilayered anatomical model at a lower cost and more easily than with established methods, by using a meshlike structure as the surface layer. Fused deposition modeling-type three-dimensional printers were used, with opaque polylactide filament for material. Using the three-dimensional data-editing software Blender (Blender Foundation, www.blender.org) and Instant Meshes (Jakob et al., https://igl.ethz.ch/projects/instant-meshes/) together, the body surface data were converted into a meshlike structure while retaining its overall shape. The meshed data were printed together with other data (nonmeshed) or printed separately. In each case, the multilayer model in which the layer of the body surface was meshed could be output without any trouble. It was possible to grasp the positional relationship between the body surface and the deep target, and it was clinically useful. The total work time for preparation and processing of three-dimensional data ranged from 1 hour to several hours, depending on the case, but the work time required for converting into a meshlike shape was about 10 minutes in all cases. The filament cost was $2 to $8. In conclusion, the authors devised a method to create a three-dimensional multilayered anatomical model to easily visualize positional relationships within the structure by converting the surface layer into a meshlike structure. This method is easy to adopt, regardless of the available facilities and economic environment, and has broad applications.

3D Printed Surgical Guides Applied in Rhinoplasty to Help Obtain Ideal Nasal Profile

INTRODUCTION

As computer simulation for rhinoplasty continues to rise, the technology's utility extends beyond increasing patient conversion. Virtual simulation of the surgical result can assist with surgical planning and intraoperative decision-making. 3D printed anatomic models or surgical guides based on 3D images may help align surgeons with their original surgical plan. This study aims to evaluate the utility of 3D printed surgical guides as an intraoperative tool to help establish dorsal height and tip position.

METHODS

Patients undergoing rhinoplasty had preoperative virtual 3D surgical simulations performed. Simulations were used to create a 3D printed nasal kits containing ceramic models of the preoperative nose and simulated nose, sagittal contour guide, and customized postoperative nasal splint. Nasal guides were sterilized for continual intraoperative assessment of profile contour (i.e., dorsal height and tip position). Postoperative 3D images (1-3 months post-op) were then compared to preoperative simulations. The difference between z coordinates and y coordinates determined the difference in projection and rotation, respectively.

RESULTS

Fifteen patients met inclusion criteria for this study. With the use of 3D printed surgical guides, the final tip position was on average of 0.8±0.7mm from simulated projection and 0.3±0.2mm from simulated rotation. Similarly, projection for the cartilaginous and bony dorsum was within 1.0±0.8 and 0.8±0.7mm of the simulation, respectively.

CONCLUSION

Virtual simulation is useful in defining aesthetic goals preoperatively, but the potential clinical value extends beyond this. 3D printed rhinoplasty guides extend the simulation's utility to decision-making intraoperatively. This technology offers a novel medium for anatomic reference, which may improve adherence to desired aesthetic goals.

LEVEL OF EVIDENCE V

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine Ratings, please refer to Table of Contents or online Instructions to Authors www.springer.com/00266 .

Evaluation and treatment of facial feminization surgery: part I. forehead, orbits, eyebrows, eyes, and nose

Facial feminization surgery (FFS) incorporates aesthetic and craniofacial surgical principles and techniques to feminize masculine facial features and facilitate gender transitioning. A detailed understanding of the defining male and female facial characteristics is essential for success. In this first part of a two-part series, we discuss key aspects of the general preoperative consultation that should be considered when evaluating the prospective facial feminization patient. Assessment of the forehead, orbits, hairline, eyebrows, eyes, and nose and the associated procedures, including scalp advancement, supraorbital rim reduction, setback of the anterior table of the frontal sinus, rhinoplasty, and soft tissue modifications of the upper and midface are discussed. In the second part of this series, bony manipulation of the midface, mandible, and chin, as well as soft tissue modification of the nasolabial complex and chondrolaryngoplasty are discussed. Finally, a review of the literature on patient-reported outcomes in this population following FFS is provided.

Conformity of the Virtual Surgical Plan to the Actual Result Comparing Five Craniofacial Procedure Types

BACKGROUND

The "accuracy" of virtual surgical planning across multiple procedure types is not known. The authors aimed to compare the planned outcome from virtual surgical planning to the actual postoperative outcome for five craniofacial procedure types performed by a single surgeon: implant cranioplasty, cranial vault remodeling, orthognathic surgery, mandible reconstruction, and mandibular distraction.

METHODS

Stereolithography formats were obtained from virtual surgical planning and compared to postoperative computed tomographic scans for consecutive patients who underwent one of the five procedure types. Volumetric renderings of the operated bony region of interest were overlaid and compared using a Boolean operation to compute conformity (as a percentage of the region of interest). Conformity across procedure type was analyzed using analysis of variance and post hoc Bonferroni analysis, where appropriate.

RESULTS

One hundred thirty patients were included (51.5 percent male and 49.5 percent female; mean age, 27 years; 59 orthognathic surgery, 32 cranial vault remodeling, 16 mandible reconstruction, 12 mandibular distraction, and 11 implant cranioplasty patients). The highest tier of conformity was obtained for implant cranioplasty (median, 76.8 ± 10.3 percent) and mandible reconstruction (mean, 69.4 ± 11.2 percent), followed by orthognathic surgery (mean, 55.0 ± 7.3 percent) and mandibular distraction (median, 41.9 ± 20.3 percent), followed by cranial vault remodeling (mean, 22.2 ± 12.1 percent) (p < 0.001 between tiers and p > 0.05 among tiers).

CONCLUSIONS

Virtual surgical planning resulting in custom permanent implants and intraoperative guides provides more predictable results compared to virtual surgical planning used for procedures involving higher degrees of skeletal repositioning and postoperative movement (i.e., mandibular distraction and nonrigid cranial vault remodeling). In cases with expectedly lower conformity, excellent outcomes can be achieved with sound intraoperative judgment.

Three-Dimensional Analysis and Surgical Planning for Open Correction of Trigonocephaly

SUMMARY

Metopic craniosynostosis results in trigonocephaly, characterized by a triangular forehead with metopic ridge, bitemporal pinching, and narrow-set eyes with recessed lateral orbital rims. Surgical management is controversial but may include open expansion and vault remodeling, to enhance neurocognitive and aesthetic outcomes. This article and video vignette depict the diagnosis and treatment of metopic craniosynostosis, demonstrating the senior author's open approach, three-dimensional virtual surgical planning, and technical steps.

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-assisted mandibular curved osteotomy: An automatic method to design the new aesthetic gonion and osteotomy line

BACKGROUND

Digital technology has been widely used in mandibular curved osteotomy to improve accuracy. However, the planning process still highly dependent on the experience and judgement of the surgeon. This study describes an automatic method to design the new gonion and osteotomy line based on the aesthetic standards in attractive women, and assesses its clinical outcomes.

METHODS

An automatic surgical planning method for mandibular curved osteotomy was developed based on our previous research of mandibular angle aesthetics. A prospective clinical study was conducted from April 2016 to April 2018. Twenty-five female patients with prominent mandibular angle were enrolled. Pre- and postoperative skull computed tomography (CT) was performed. Three-dimensional (3D) CT data were obtained and processed by Mimics 18.0. Surgical templates were designed according to the automatic surgical planning method and 3D printed for the surgery. Preoperative measurements, surgical simulation and postoperative measurements were taken to evaluate the surgical outcomes.

RESULTS

There were significant differences between the preoperative and the postoperative groups' results (p < 0.01). There was no difference between the surgical simulation and the postoperative results. All postoperative measurements were consistent with aesthetic features of mandibles. Patients were satisfied with their outcomes in terms of outline, symmetry and lower facial width.

CONCLUSIONS

Our study developed an automatic method to position the new aesthetic gonion and osteotomy line for prominent mandibular angle patients. We proved that this method is safe, effective and reliable.

Multiscale sterilizable 3D printed auricular templates to guide cartilaginous framework sizing and sculpture during autologous microtia reconstruction

Microtia reconstruction using autologous costal cartilage can be one of the most challenging tasks in reconstructive surgery. An intraoperative guide using 2-dimentional drawing of the contralateral ear on an x-ray film remains the current standard of care. In this paper, we present the use of computer-aided design and desktop 3D printing to fabricate low cost, sterilizable auricular carving templates to serve as a peri-operative reference for microtia reconstruction. The design was made as a single component which incorporated the usual anatomic reference points of the ear based on Nagata technique as a Stereo-lithography file format (. STL) for 3D printing. The templates were created in sizes ranging from 55 mm to 70 mm with a 2 mm increment with an average production cost of 0.26 US dollars per material per template and about 4.5 US dollars for the whole set. Individual templates were then 3D-printed using a thermoplastic polyurethane (TPU 95A) semiflexible filament on a desktop fused deposition modeling, Ultimaker 2 + 3D printer. The produced template tolerated the sterilization process with no structural changes as compared to its pre-sterilization condition. In conclusion, we present cost-effective, sterilizable, multiscale auricular templates to guide the pre- and intra-operative carving of the cartilaginous framework during microtia reconstruction with more accuracy in a time efficient manner, thereby overcoming the drawbacks of using the traditional x-ray film. The templates are readily accessible and sharable for free through open-source software and can be directly 3D-printed using an affordable desktop 3D printer.

Three-Dimensional Computer-Assisted Orthognathic Surgery: Traditional Hybrid Versus Full Digital Planning Models

PURPOSE

Three-dimensional (3D) computer-aided planning has truly revolutionized orthognathic surgery (OGS) treatment, but no study has compared the traditional hybrid and full 3D digital planning models. This study compared these virtual planning models in the treatment of asymmetric maxillomandibular disharmony.

METHODS

Young adult patients with an asymmetric skeletal class III deformity who underwent 3D computer-aided 2-jaw OGS using hybrid (alginate dental impression, 2D cephalometric tracings, manual-guided stone model surgery, occlusion setup, and splint fabrication; n = 30) or full digital (laser-scanned dentition, 3D cephalometric tracings, virtual-based occlusion setup and surgery, and computer-generated surgical splint; n = 30) planning models were consecutively recruited. Preoperative and postoperative 3D cephalometric analyses (dental relation, skeletal assessments based on sagittal and frontal views, and soft tissue evaluations) were adopted for intragroup and intergroup comparisons. Postoperative patient-perceived satisfaction with facial appearance was also recorded.

RESULTS

Both hybrid and full digital planning groups had significant (all P < 0.05) improvements after surgery with respect to facial convexity, incisor overjet, and frontal symmetry parameters. The full 3D digital planning-based OGS treatment had similar (all P > 0.05) 3D cephalometric-derived outcomes (preoperative, postoperative, and treatment-induced change data) and patient-perceived outcomes compared with the traditional hybrid 3D planning method.

CONCLUSIONS

For the decision-making process in selecting the planning model, multidisciplinary teams could consider additional parameters such as patient comfort, storage needs, convenience for data reuse, overall planning time, availability, and costs.

Comparative Study of Three-Dimensional Volume Measurement for Facial Fat Grafting

ABSTRACT

The three-dimensional (3D) volume measurement after facial fat grafting is of great significance to plastic surgeons. It has been ascertained that reliable results rely on the accurate measurement of 3D softwares. Some 3D softwares in literatures have proposed various ways to optimize each step of the procedure, including the pre- and post-operative image acquisition, alignment, calculation, and analysis. Good image alignment between pre- and post-scan is essential to quantify the volumetric change. Once the pre- and post-operative image alignment has slightly bias or deviation, the subsequent volume measurement would also be affected. To our knowledge, 2 types of 3D software have been widely applied in clinic, primarily based on the image-automatically alignment and image-manually alignment. This study aimed to compare the accuracy, repeatability, and reproducibility of the Geomagic Qualify 12.0 software and the 3-Matic 7.0 software in a relatively ideal model of virtual facial fat grafting. A simulated facial fat grafting was first performed for 10 preoperative patients diagnosed with progressive hemifacial atrophy, and the known volumetric change was named as the true value (T value). Then, the facial volumetric change of every case was remeasured 10 times with above 2 kinds of software separately. The mean volumetric change was calculated as Q value and M value. The paired t test, intraclass correlation coefficient, and Bland-Altman analysis showed that the Geomagic Qualify 12.0 software demonstrated a statistically higher accuracy, repeatability, and reproducibility in comparison with the 3-Matic 7.0 software.

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.

Computer-Aided Design and Manufacturing Cutting and Drilling Guides with Prebent Titanium Plates Improve Surgical Accuracy of Skeletal Class III Malocclusion

BACKGROUND

The aim of this study was to evaluate the effects of the use of computer-aided design and manufacturing cutting and drilling guides with prebent titanium plates for the correction of skeletal class III malocclusion.

METHODS

In this prospective, randomized, controlled clinical trial, 46 patients with skeletal class III malocclusion were randomly assigned into two groups. The patients underwent bimaxillary surgery with computer-aided design and manufacturing cutting and drilling guides with prebent titanium plates (experimental group) or computer-aided design and manufacturing splints (control group). Preoperative and postoperative imaging data were collected and then analyzed using Mimics Research 19.0, Geomagic Studio, and IBM SPSS Version 21.0.

RESULTS

Deformity evaluation and posttreatment assessment were performed for all patients. The experimental group had fewer postoperative complications. Comparison of the linear and angular differences to facial reference planes revealed more accurate repositioning of the mandible and condyles in the experimental group, although the position of several landmarks still requires small adjustments.

CONCLUSION

Computer-aided design and manufacturing cutting and drilling guides with prebent titanium plates effectively corrected skeletal class III malocclusion, providing positional control of segments with reasonable surgical accuracy.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

Clinical Application of a Patient-Specific, Three-Dimensional Printing Guide Based on Computer Simulation for Rhinoplasty

BACKGROUND

A practical application of three-dimensional printing technology has been considered a difficult area in rhinoplasty. However, the patient-specific three-dimensionally printed rhinoplasty guide based on the simulation program the authors developed could be a solution for minimizing the gap between simulation and actual surgical results. The aims of this study were to determine how a three-dimensional rhinoplasty guide based on three-dimensional simulation would link the patient to the surgeon to investigate its effectiveness.

METHODS

Fifty patients who underwent rhinoplasty between January of 2017 and February of 2018 were included in this study. The patients were consulted about the desired shape of their nose based on preoperative three-dimensional photography. The confirmed three-dimensional simulation was sent to a manufacturing company for three-dimensionally printed rhinoplasty guides. In the guide group, rhinoplasty was performed based on the three-dimensionally printed rhinoplasty guide, and in the control group, procedures were performed based on the surgeon's intuition.

RESULTS

The intraclass correlation coefficient test for comparing the simulated and postoperative measurements showed higher correlation in the three-dimensional printing guide group: higher correlation 11.3 percent in nasal tip projection, 21.6 percent in dorsum height, and 9.8 percent in nasolabial angle. The postoperative result of the nasal dorsum had a statistically significant difference between the two groups (p < 0.05).

CONCLUSIONS

This study demonstrated the usefulness of the three-dimensionally-printed rhinoplasty guide, which delivers the preoperative simulated image in the actual clinical practice of rhinoplasty. This approach could cause a paradigm shift in simulation-based rhinoplasty.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Correction of Sagittal Synostosis Using Three-Dimensional Planning and Maltese Cross Geometry

There are several approaches to correct sagittal synostosis. Regardless of technique, the goals are to (1) release the fused suture and (2) impart a normocephalic head shape with resultant functional and aesthetic benefits. This article and video detail the authors' preferred technique for the treatment of sagittal synostosis. This novel method involves three-dimensional planning and an open approach to focus on immediate correction of the anteroposterior, mediolateral, and vertex dimensions, using vault remodeling, pedicled osseous ("Maltese") crosses, and corset pericranial flaps.

Virtual Surgical Planning for Successful Second-Stage Mandibular Defect Reconstruction Using Vascularized Iliac Crest Bone Flap: A Valid and Reliable Method

PURPOSE

Second-stage reconstruction of mandibular defects faces problems of anatomic disorder and bone displacement due to tumor resection. As a newer technique, virtual surgical planning (VSP) may help to increase the accuracy and efficiency of the complicated reconstruction. This study aims to evaluate the application of VSP and splint-guided surgery in second-stage mandibular reconstruction using vascularized iliac crest bone flap.

METHODS

Between October 2016 and February 2018, 5 patients (3 men and 2 women) with mandibular defects of duration between 8 months and 8 years underwent VSP-aided secondary reconstruction in the School and Hospital of Stomatology of Wuhan University (Wuhan, China). Virtual surgical planning was performed and serial guiding splints were printed to replicate the design into the actual operation. The linear and 3-dimensional deviations after surgery were analyzed. Patient complications and feedback were recorded during follow up.

RESULTS

All 5 patients underwent successful reconstruction using vascularized iliac crest bone flap. No serious donor sites or recipient site complications were observed after 10- to 28-month follow-up. In comparison with the presurgery designs, the linear deviations in coronal plane were 2.7 ± 0.4 mm (range, -2.2 to 3.9 mm) in measurements from the condylar head to the condylar head and 0.70 ± 0.6 mm (range, -0.1 to 1.7 mm) from the gonial angle to the gonial angle, and that in sagittal plane was 2.4 ± 0.88 mm (range, -3 to 4.4 mm) from the anterior inferior mandibular border to the center point on the condylar head to the condylar head line. The whole 3-dimensional deviation was 1.2 ± 1.7 mm in all patients.

CONCLUSION

Well-designed splints can assist in precise mandibular reconstruction with high efficiency and accuracy, and thus are a reliable method for complicated second-stage mandibular reconstruction. However, to achieve a better outcome, a satisfactory design is required to adapt the complicated and varied defect.

Computer-Assisted Design and Manufacturing Assists Less Experienced Surgeons in Achieving Equivalent Outcomes in Cranial Vault Reconstruction

PURPOSE

The purpose of this study was to assess whether long-term outcomes were equivalent between computer-assisted design and manufacturing (CAD/CAM) -assisted cranial vault reconstruction performed by an inexperienced surgeon, with fewer years of surgical experience, and traditional reconstruction performed by senior surgeons with many decades of experience.

METHODS

An Institutional Review Board-approved retrospective cohort study was performed for all patients with nonsyndromic craniosynostosis between the ages of 1 month to 18 years who received primary, open calvarial vault reconstruction at the Johns Hopkins Hospital between 1990 and 2017. The primary outcome variable was the Whitaker category (I-IV) for level of required revision at the 2-year follow-up visit. Secondary outcomes included estimated blood loss, length of stay, operative time, and postoperative complications. CAD/CAM-assisted surgery was considered noninferior if the proportion of cases requiring any revision (Whitaker II, III, or IV) was no more than 10% greater than the proportion in the traditional surgery group with multivariate logistic regression analysis. t tests and fisher exact tests were used for secondary outcomes.

RESULTS

A total of 335 patients were included, with 35 CAD/CAM-assisted reconstructions. CAD/CAM-assisted reconstruction was noninferior to traditional after accounting for patient demographics, type of surgery, and experience level of the plastic surgeon. The traditional group required revision more frequently at 29.0% compared to CAD/CAM at 14.3%. Secondary outcomes were not significantly different between groups, but CAD/CAM had significantly longer average operative times (5.7 hours for CAD/CAM, 4.3 hours for traditional, P < 0.01).

CONCLUSION

CAD/CAM technology may lower the learning curve and assist less experienced plastic surgeons in achieving equivalent long-term outcomes in craniofacial reconstruction.

A machine learning framework for automated diagnosis and computer-assisted planning in plastic and reconstructive surgery

Current computational tools for planning and simulation in plastic and reconstructive surgery lack sufficient precision and are time-consuming, thus resulting in limited adoption. Although computer-assisted surgical planning systems help to improve clinical outcomes, shorten operation time and reduce cost, they are often too complex and require extensive manual input, which ultimately limits their use in doctor-patient communication and clinical decision making. Here, we present the first large-scale clinical 3D morphable model, a machine-learning-based framework involving supervised learning for diagnostics, risk stratification, and treatment simulation. The model, trained and validated with 4,261 faces of healthy volunteers and orthognathic (jaw) surgery patients, diagnoses patients with 95.5% sensitivity and 95.2% specificity, and simulates surgical outcomes with a mean accuracy of 1.1 ± 0.3 mm. We demonstrate how this model could fully-automatically aid diagnosis and provide patient-specific treatment plans from a 3D scan alone, to help efficient clinical decision making and improve clinical understanding of face shape as a marker for primary and secondary surgery.

Application of Three-Dimensional Printing Technology for Improved Orbital-Maxillary-Zygomatic Reconstruction

The reconstruction of orbital-maxillary-zygomatic complex (OMZC) on patients suffering from trauma and space-occupying lesions is challenging due to the irregularity of craniomaxillofacial bones. To overcome the challenge in precise OMZC reconstruction, individual three-dimensional (3D) disease models and mirror-imaged 3D reconstruction models were printed on the basis of the computer tomography. Preoperative planning by rehearsing surgical procedures was made on the 3D disease models and the scaffolds including titanium and absorbable meshes or plates were anatomically premolded using the mirror-imaged 3D models as guide. Many benefits were achieved including more precise OMZC reconstruction, fluent and smooth procedures of surgeries, shorter operation time, less blood loss, and improved cosmetic outcomes of craniomaxillofacial shapes. There were no complications such as diplopia, infection, foreign body reaction, exophthalmos, enophthalmos, disordered occlusal relationship, and hematoma. And patients were satisfied with the functional and esthetic outcome during the following-up time. Therefore, OMZC reconstruction can be optimized and successful through preoperative planning and premolded scaffolds with 3D printing bone model by computer-aid design and manufacturing.

Comparison of Complicated and Simple Guiding Templates in Mandibular Reconstruction Using Vascularized Iliac Crest Flap

Objective

This study aims to compare the degree of accuracy achieved in mandibular reconstruction between complicated guiding templates (CGT) and simple guiding templates (SGT), to evaluate the necessity to spend more time to design complicated templates prior to surgery.

Methods

The preoperative virtual surgery plan (VSP) was used to simulate the osteotomy and accurate mandibular reconstruction strategy. Then the guiding templates were designed and printed to transfer the VSP into the real operation. Between July 2013 and November 2014, we used the SGT in 13 L-type mandibular defect reconstructions utilising vascularized iliac crest bone (VICB). From March 2015 to March 2018, we used CGT in 14 L-type mandibular defects, also reconstructing with VICB. The indicators of mandibular symmetry, midline deviation, alveolar height loss, bone conjunction gap, and operation time were analyzed and compared between the two groups.

Results

The overall bone graft success rate was 100% (27/27) between all patients. The SGT and CGT groups showed similar symmetry (1.01 ± 0.03 vs. 1.03 ± 0.04, P = 0.11) and mandibular midline displacement (1.0 ± 0.7 mm vs. 1.2 ± 0.8 mm, P=0.29). The CGT group showed less alveolar height deficiency than the SGT group (3.0 ± 2.4 mm vs. 7.8 ± 6.8 mm, P=0.01) and lesser bony conjunction gap between the graft and the mandible (1.6 ± 0.7 mm vs. 2.4 ± 1.2 mm, P = 0.02). The average operation time was significantly lower in the CGT group than in the SGT group (340.5 ± 74 min vs. 391.9 ± 41.7 min, P = 0.02).

Conclusion

In the simple mandibular reconstruction, the time-consuming CGT did not significantly improve the symmetry and midline displacement compared to SGT, but it demonstrated less reduction (increased preservation) in alveolar height and decreased the size of the bone conjunction gap. And in addition, CGT also reduced the average operation time and simplified intraoperative procedures compared with SGT.

Matching locating holes in multiple plates to record bone position for accurate reconstruction after segmental mandibulectomy

Segmental defect areas in the mandible can change immediately following osteotomy due to muscular traction, impacting on accurate reconstruction. The purpose of this article is to introduce a new technique based on virtual surgery planning to record the position of the bony parts prior to mandibulectomy, for use in precise mandibular reconstruction after segmental osteotomy. The position information for the bony parts is transferred to a plate with complementary surface contact and locating holes with specific directions and angles. This technique was performed for six patients with segmental defects and the results were compared to those of six previous patients in whom the technique was not utilized. The design of the location holes shortened the average operation time from 406 minutes to 349 minutes (P = 0.033) and decreased the average, maximum, and minimum graft deviation from 1.21 mm to 0.88 mm (P = 0.015), 1.28 mm to 0.99 mm (P = 0.027), and -1.15 mm to -0.77 mm (P = 0.077), respectively. The design of the locating holes in multiple plates shortened the time taken for the bony repositioning step and hence significantly shortened the total operation time. More importantly, it also increased the reconstructive accuracy.

Three-Dimension-Printed Surgical Guide for Accurate and Safe Mandibuloplasty in Patients With Prominent Mandibular Angles

Performance of mandibuloplasty is highly dependent on each surgeon's experience, and reproducing the results of simulation surgery is often difficult. In order to obtain successful clinical outcomes, a fast and efficient surgery technique that minimizes operation time and risk to patients is needed. The authors designed a 3D-printed mandible fit surgical guide for use as a bridge between simulation and actual surgery.The authors enrolled 7 patients with prominent mandibular angle who visited the outpatient clinic of the Department of Plastic and Reconstructive Surgery at Asan Medical Center in Seoul, Korea between December 2013 and May 2017.The surgical guides were made with a 3D printer and simulated based on individual facial bone CT scans. The surgical guides were designed to fit the lower border of the mandible and to cover the portion planned for removal.The resulting personalized 3D-printed surgical guides were applied on both mandibular angles to the body and along the lower border of the mandible. Osteotomy of the mandibular angle and body were performed along the surgical guide. All patients recovered without any immediate postoperative complications. The use of 3D-printed surgical guide was effective in simplifying the process of mandibuloplasty.Our results demonstrate the value of 3D printing technology in mandibuloplasty.

Three-dimensional Assessment of the Breast: Validation of a Novel, Simple and Inexpensive Scanning Process

BACKGROUND/AIM

Methods to assess three-dimensionally the breast surface are increasingly used in plastic and reconstructive surgery. The aim of this study was to validate the use of the Structure Sensor 3D scanner (Occipital, Inc., Boulder, CO, USA) connected to an iPad Pro (Apple, Inc., Cupertino, CA, USA) as a novel, inexpensive and handheld three-dimensional scanning process.

MATERIALS AND METHODS

Surface images of a medical human female anatomy torso model of rigid plastic were repeatedly acquired with Structure Sensor 3D scanner and compared with those obtained using two clinically established 3D imaging systems. Digital measurements of vector and surface breast distances were analyzed using Mimics® Innovation Suite 20 medical imaging software (Materialise, Leuven, Belgium).

RESULTS

The analysis of variance (ANOVA) revealed no statistically significant difference among measurements obtained using different scanning processes for all the variables examined (p>0.05).

CONCLUSION

The study demonstrates analogous practicability and reliability for surface image acquisition using the newly introduced Structure Sensor 3D scanner and other clinically established scanners.

Virtual Surgical Planning Decreases Operative Time for Isolated Single Suture and Multi-suture Craniosynostosis Repair

Background

Cranial vault reconstruction is a complex procedure due to the need for precise 3-dimensional outcomes. Traditionally, the process involves manual bending of calvarial bone and plates. With the advent of virtual surgical planning (VSP), this procedure can be streamlined. Despite the advantages documented in the literature, there have been no case-control studies comparing VSP to traditional open cranial vault reconstruction.

Methods

Data were retrospectively collected on patients who underwent craniosynostosis repair during a 7-year period. Information was collected on patient demographics, intraoperative and postoperative factors, and intraoperative surgical time. High-resolution computed tomography scans were used for preoperative planning with engineers when designing osteotomies, bone flaps, and final positioning guides.

Results

A total of 66 patients underwent open craniosynostosis reconstruction between 2010 and 2017. There were 35 control (non-VSP) and 28 VSP cases. No difference in age, gender ratios, or number of prior operations was found. Blood loss was similar between the 2 groups. The VSP group had more screws and an increased length of postoperative hospital stay. The length of the operation was shorter in the VSP group for single suture and for multiple suture operations. Operative time decreased as the attending surgeon increased familiarity with the technique.

Conclusions

VSP is a valuable tool for craniosynostosis repair. We found VSP decreases surgical time and allows for improved preoperative planning. Although there have been studies on VSP, this is the first large case-control study to be performed on its use in cranial vault remodeling.

Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): guidelines for medical 3D printing and appropriateness for clinical scenarios

Medical three-dimensional (3D) printing has expanded dramatically over the past three decades with growth in both facility adoption and the variety of medical applications. Consideration for each step required to create accurate 3D printed models from medical imaging data impacts patient care and management. In this paper, a writing group representing the Radiological Society of North America Special Interest Group on 3D Printing (SIG) provides recommendations that have been vetted and voted on by the SIG active membership. This body of work includes appropriate clinical use of anatomic models 3D printed for diagnostic use in the care of patients with specific medical conditions. The recommendations provide guidance for approaches and tools in medical 3D printing, from image acquisition, segmentation of the desired anatomy intended for 3D printing, creation of a 3D-printable model, and post-processing of 3D printed anatomic models for patient care.

Updates in Head and Neck Reconstruction

LEARNING OBJECTIVES

After reading this article, the participant should be able to: 1. Have a basic understanding of virtual planning, rapid prototype modeling, three-dimensional printing, and computer-assisted design and manufacture. 2. Understand the principles of combining virtual planning and vascular mapping. 3. Understand principles of flap choice and design in preoperative planning of free osteocutaneous flaps in mandible and midface reconstruction. 4. Discuss advantages and disadvantages of computer-assisted design and manufacture in reconstruction of advanced oncologic mandible and midface defects.

SUMMARY

Virtual planning and rapid prototype modeling are increasingly used in head and neck reconstruction with the aim of achieving superior surgical outcomes in functionally and aesthetically critical areas of the head and neck compared with conventional reconstruction. The reconstructive surgeon must be able to understand this rapidly-advancing technology, along with its advantages and disadvantages. There is no limit to the degree to which patient-specific data may be integrated into the virtual planning process. For example, vascular mapping can be incorporated into virtual planning of mandible or midface reconstruction. Representative mandible and midface cases are presented to illustrate the process of virtual planning. Although virtual planning has become helpful in head and neck reconstruction, its routine use may be limited by logistic challenges, increased acquisition costs, and limited flexibility for intraoperative modifications. Nevertheless, the authors believe that the superior functional and aesthetic results realized with virtual planning outweigh the limitations.