Virtual Surgical Planning in Oral and Maxillofacial Surgery

Evolution of Virtual Surgical Planning Use Among Craniofacial Surgeons

Virtual surgical planning (VSP) has benefits in craniofacial surgery with growing popularity. However, while specific use cases are highlighted in the literature, no studies exist providing an overview of VSP use among craniofacial surgeons, and little is known about the extent of exposure to VSP during plastic surgery training. This study surveyed members of The American Society of Maxillofacial Surgeons (ASMS) to better characterize both the landscape of VSP use among practicing craniofacial surgeons and the extent of exposure to VSP throughout surgical training. An electronic survey was administered in the fall of 2023. Response data included surgeon demographics, VSP usage, including the use in residency/fellowship, procedures for which VSP is used, and assessment of VSP's impact on the surgeon's practice. Demographics and VSP use were analyzed using descriptive statistics, while categorical and continuous variables were analyzed using χ2 tests and t-tests, respectively. Of the 44 respondents, 40 (90.9%) completed a craniofacial surgery fellowship, and 18 (40.9%) utilized VSP in either residency or fellowship. In respondents' current practice, VSP is utilized most commonly for orthognathic surgery (n=32, 91.4%), postablative reconstruction (n=23, 82.1%), and facial feminization (n=11, 73.3%). Shorter operative time and improved esthetic outcomes were frequently reported as benefits derived from VSP use. Finally, surgeons in practice for less than 10 years were significantly more likely to have used VSP in both residency (OR=20.3, P<0.01) and in fellowship (OR=40.6, P<0.01) than those practicing for more than 10 years. These findings suggest that craniofacial surgeons apply VSP more commonly for certain procedure types. Our results additionally suggest that incorporation of VSP into residency and fellowship training has become significantly more common over time, with a pivot towards integration in the last decade.

A New Approach to Virtual Occlusion in Orthognathic Surgery Planning Using Mixed Reality-A Technical Note and Review of the Literature

Orthognathic surgery plays a vital role in correcting various skeletal discrepancies of the maxillofacial region. Achieving optimal occlusion is a fundamental aspect of orthognathic surgery planning, as it directly influences postoperative outcomes and patient satisfaction. Traditional methods for setting final occlusion involve the use of dental casts which are time-consuming, prone to errors and cannot be easily shared among collaborating specialties. In recent years, advancements in digital technology have introduced innovative approaches, such as virtual occlusion, which may offer enhanced accuracy and efficiency in orthognathic surgery planning. Furthermore, the emergence of mixed reality devices and their 3D visualization capabilities have brought about novel benefits in the medical field, particularly in computer-assisted planning. This paper presents for the first time a prototype tool for setting virtual occlusion during orthognathic surgery planning using mixed reality technology. A complete walkthrough of the workflow is presented including an explanation of the implicit advantages of this novel tool. The new approach to defining virtual occlusion is set into context with other published methods of virtual occlusion setting, discussing advantages and limitations as well as concepts of surgical occlusion for orthognathic surgery.

Virtual surgical planning in craniomaxillofacial surgery: a structured review

Craniomaxillofacial (CMF) surgery is a challenging and very demanding field that involves the treatment of congenital and acquired conditions of the face and head. Due to the complexity of the head and facial region, various tools and techniques were developed and utilized to aid surgical procedures and optimize results. Virtual Surgical Planning (VSP) has revolutionized the way craniomaxillofacial surgeries are planned and executed. It uses 3D imaging computer software to visualize and simulate a surgical procedure. Numerous studies were published on the usage of VSP in craniomaxillofacial surgery. However, the researchers found inconsistency in the previous literature which prompted the development of this review. This paper aims to provide a comprehensive review of the findings of the studies by conducting an integrated approach to synthesize the literature related to the use of VSP in craniomaxillofacial surgery. Twenty-nine related articles were selected as a sample and synthesized thoroughly. These papers were grouped assigning to the four subdisciplines of craniomaxillofacial surgery: orthognathic surgery, reconstructive surgery, trauma surgery and implant surgery. The following variables - treatment time, the accuracy of VSP, clinical outcome, cost, and cost-effectiveness - were also examined. Results revealed that VSP offers advantages in craniomaxillofacial surgery over the traditional method in terms of duration, predictability and clinical outcomes. However, the cost aspect was not discussed in most papers. This structured literature review will thus provide current findings and trends and recommendations for future research on the usage of VSP in craniomaxillofacial surgery.

3D surgical instrument collection for computer vision and extended reality

The availability of computational hardware and developments in (medical) machine learning (MML) increases medical mixed realities' (MMR) clinical usability. Medical instruments have played a vital role in surgery for ages. To further accelerate the implementation of MML and MMR, three-dimensional (3D) datasets of instruments should be publicly available. The proposed data collection consists of 103, 3D-scanned medical instruments from the clinical routine, scanned with structured light scanners. The collection consists, for example, of instruments, like retractors, forceps, and clamps. The collection can be augmented by generating likewise models using 3D software, resulting in an inflated dataset for analysis. The collection can be used for general instrument detection and tracking in operating room settings, or a freeform marker-less instrument registration for tool tracking in augmented reality. Furthermore, for medical simulation or training scenarios in virtual reality and medical diminishing reality in mixed reality. We hope to ease research in the field of MMR and MML, but also to motivate the release of a wider variety of needed surgical instrument datasets.

A fully digital workflow for prosthetically driven alveolar augmentation with intraoral bone block and implant rehabilitation in an atrophic anterior maxilla

A fully digital workflow for prosthetically driven alveolar augmentation and implant rehabilitation in the esthetic zone was planned and executed by using a bone harvest guide, trim guide, graft guide, and implant guide. A controllable procedure and predictable results can be realized by adopting this digital workflow.

Applications of three-dimensional imaging techniques in craniomaxillofacial surgery: A literature review

Three-dimensional (3D) imaging technologies are increasingly used in craniomaxillofacial (CMF) surgery, especially to enable clinicians to get an effective approach and obtain better treatment results during different preoperative and postoperative phases, namely during image acquisition and diagnosis, virtual surgical planning (VSP), actual surgery, and treatment outcome assessment. The article presents an overview of 3D imaging technologies used in the aforementioned phases of the most common CMF surgery. We searched for relevant studies on 3D imaging applications in CMF surgery published over the past 10 years in the PubMed, ProQuest (Medline), Web of Science, Science Direct, Clinical Key, and Embase databases. A total of 2094 articles were found, of which 712 were relevant. An additional 26 manually searched articles were included in the analysis. The findings of the review demonstrated that 3D imaging technology is becoming increasingly popular in clinical practice and an essential tool for plastic surgeons. This review provides information that will help researchers and clinicians consider the use of 3D imaging techniques in CMF surgery to improve the quality of surgical procedures and achieve satisfactory treatment outcomes.

An Overview of Clinical Conditions and a Systematic Review of Personalized TMJ Replacement

The temporomandibular joint (TMJ) is a complex structure in the cranio-maxillomandibular region. The pathological changes of the joint cause deficiencies at different levels, making its replacement necessary in some cases. The aim of this article is to analyze the current indications, treatment and criteria, and follow-up using a systematic review and case series. A systematic review was carried out, identifying the indications for the use of a customized TMJ prosthesis and evaluating criteria and validation in the international literature. After review and exclusion, 8 articles were included with a minimum follow-up of 12 months. The age of the subjects was between 18 and 47 years old. In 226 patients, 310 TMJ prostheses were installed, 168 bilaterally and 142 unilaterally. In most of the articles, a good condition in the follow-up was observed, with a reduction in pain and better conditions of mandibular movement and function. TMJ prosthesis and replacement is a protocolized, defined, stable, and predictable procedure. Indications and criteria must be evaluated by specialists and patients related to the pathology involved in TMJ deformity or degeneration. Randomized research with an accurate diagnosis and follow-up is necessary to obtain the best indication for this treatment.

Rehabilitation of long-term mandibular defects by whole-process digital fibula flap combining with implants: A case report

Currently, the gold standard and workhorse in mandibular reconstruction is the free vascularized fibula flap. Particularly for patients who have had mandibulectomy for a long time, it is still difficult to precisely reconstruct the mandibular contour and successfully restore the patient's chewing function and esthetics. For the restoration and rehabilitation of long-term mandibular abnormalities, three-dimensional (3D) virtual surgical planning (VSP) and 3D-printed surgical guides are essential. Digital design and manufacturing were used to improve the accuracy of prostheses and facilitate occlusal reconstruction. Therefore, equipped with the methods of 3D VSP, 3D-printed surgical guides, free vascularized fibular flap, and immediate dental implants, this clinical report provides a feasible solution for mandibular reconstruction.

Familial Gigantiform Cementoma: Life-Saving Total Midface Resection and Reconstruction Using Virtual Surgical Planning and 3D Printed Patient-Specific Implant-A Clinical Study

Background

Familial gigantiform cementoma (FGC) is a rare benign fibrocemento-osseous lesion of the jaw characterized by well-circumscribed, extensive, mixed radiolucent-radiopaque masses in the mandible and the maxilla that can cause severe facial deformity. This condition is extremely rare with less than 40 cases reported in the literature.

Purpose

The purpose of the paper is to highlight the importance of virtual surgical planning and patient-specific implant in the treatment of a complex lesion and reconstruction of the facial skeleton. The clinical presentations, and diagnostic challenges encountered when managing the lesion have been discussed in this article with emphasis on the treatment plan.

Method/Surgical plan

The sequence of treatment planned was resection of the lesion and immediate reconstruction with a patient-specific implant to improve the patient's quality of life. The management of FGC was a challenging one keeping in mind the rapid expansion of the lesion, widespread involvement of the jaws, and needs of the pediatric patient.

Conclusion

Virtual surgical planning (VSP) along with 3D printed implant was instrumental in reconstructing the facial form of the child where the maxilla was completely resected and rehabilitation provided support to the vital structures of the face.

Virtual reality digital surgical planning for jaw reconstruction: a usability study

BACKGROUND

Digital surgical planning (DSP) has revolutionized the preparation and execution of the management of complex head and neck pathologies. The addition of virtual reality (VR) allows the surgeon to have a three-dimensional experience with six degrees of freedom for visualizing and manipulating objects. This pilot study describes the participants experience with the first head and neck reconstructive VR-DSP platform.

METHODS

An original VR-DSP platform has been developed for planning the ablation and reconstruction of head and neck pathologies. A prospective trial utilizing this platform involving reconstructive surgeons was performed. Participants conducted a simulated VR-DSP planning session, pre- and post-questionnaire as well as audio recordings allowing for qualitative analysis.

RESULTS

Thirteen consultant reconstructive surgeons representing three surgical backgrounds with varied experience were recruited. The majority of surgeons had no previous experience with VR. Based on the system usability score, the VR-DSP platform was found to have above average usability. The qualitative analysis demonstrated the majority had a positive experience. Participants identified some perceived barriers to implementing the VR-DSP platform.

CONCLUSIONS

Virtual reality-digital surgical planning is usable and acceptable to reconstructive surgeons. Surgeons were able to perform the steps in an efficient time despite limited experience. The addition of VR offers additional benefits to current VSP platforms. Based on the results of this pilot study, it is likely that VR-DSP will be of benefit to the reconstructive surgeon.

First-Hand Experience and Result with New Robot-Assisted Laser LeFort-I Osteotomy in Orthognathic Surgery: A Case Report

BACKGROUND

We report the world's first developer-independent experience with robot-assisted laser Le Fort I osteotomy (LLFO) and drill-hole marking in orthognathic surgery. To overcome the geometric limitations of conventional rotating and piezosurgical instruments for performing osteotomies, we used the stand-alone robot-assisted laser system developed by Advanced Osteotomy Tools. The aim here was to evaluate the precision of this novel procedure in comparison to the standard procedure used in our clinic using a computer-aided design/computer-aided manufacturing (CAD/CAM) cutting guide and patient-specific implant.

METHODS

A linear Le-Fort-I osteotomy was digitally planned and transferred to the robot. The linear portion of the Le-Fort I osteotomy was performed autonomously by the robot under direct visual control. Accuracy was analyzed by superimposing preoperative and postoperative computed tomography images, and verified intraoperatively using prefabricated patient-specific implant.

RESULTS

The robot performed the linear osteotomy without any technical or safety issues. There was a maximum difference of 1.5 mm on average between the planned and the performed osteotomy. In the robot-assisted intraoperative drillhole marking of the maxilla, which was performed for the first time worldwide, were no measurable deviations between planning and actual positioning.

CONCLUSION

Robotic-assisted orthognathic surgery could be a useful adjunct to conventional drills, burrs, and piezosurgical instruments for performing osteotomies. However, the time required for the actual osteotomy as well as isolated minor design aspects of the Dynamic Reference Frame (DRF), among other things, still need to be improved. Still further studies for final evaluation of safety and accuracy are also needed.

Black Bone MRI for Virtual Surgical Planning in Craniomaxillofacial Surgery

Advances in computer-aided design and computer-aided manufacturing software have improved translational applications of virtual surgical planning (VSP) in craniomaxillofacial surgery, allowing for precise and accurate fabrication of cutting guides, stereolithographic models, and custom implants. High-resolution computed tomography (CT) imaging has traditionally been the gold standard imaging modality for VSP in craniomaxillofacial surgery but delivers ionizing radiation. Black bone magnetic resonance imaging (MRI) reduces the risks related to radiation exposure and has comparable functionality when compared with CT for VSP. Our group has studied the accuracy of utilizing black bone MRI in planning and executing several types of craniofacial surgeries, including cranial vault remodeling, maxillary advancement, and mandibular reconstruction using fibular bone. Here, we review clinical applications of black bone MRI pertaining to VSP and three-dimensional (3D)-printed guide creation for craniomaxillofacial surgery. Herein, we review the existing literature and our institutional experience comparing black bone MRI and CT in VSP-generated 3D model creation in cadaveric craniofacial surgeries including cranial vault reconstruction, maxillary advancement, and mandibular reconstruction with fibular free flap. Cadaver studies have demonstrated the ability to perform VSP and execute the procedure based on black bone MRI data and achieve outcomes similar to CT when performed for cranial vault reshaping, maxillary advancement, and mandibular reconstruction with free fibula. Limitations of the technology include increased time and costs of the MRI compared with CT and the possible need for general anesthesia or sedation in the pediatric population. VSP and 3D surgical guide creation can be performed using black bone MRI with comparable accuracy to high-resolution CT scans in a wide variety of craniofacial reconstructions. Successful segmentation, VSP, and 3D printing of accurate guides from black bone MRI demonstrate potential to change the preoperative planning standard of care. Black bone MRI also reduces exposure to ionizing radiation, which is of particular concern for the pediatric population or patients undergoing multiple scans.

Haptic-Assisted Surgical Planning (HASP) in a Case of Bilateral Mandible Fracture

Restoring normal skeletal anatomy in patients with complex trauma to the mandible can be difficult, the difficulty often increasing with an edentulous mandible. This study describes a case of a displaced edentulous bilateral mandibular fracture, which was preoperatively planned with the in-house haptic-assisted surgery planning system (HASP). A model of the virtually restored mandible was 3D-printed at the hospital and a reconstruction plate was outlined beforehand with the printed mandible as a template and served as a guide during surgery. This case suggests HASP as a valuable preoperative tool in the planning phase when dealing with maxillofacial trauma cases. With the application of virtual planning, the authors could analyze the desired outcome and were further supported in surgery by the guidance of the reconstruction plate outlined on the restored model of the mandible.

Virtual surgical planning and 3D printing: Methodology and applications in veterinary oromaxillofacial surgery

Virtual surgical planning is the process of planning and rehearsing a surgical procedure completely within the virtual environment on computer models. Virtual surgical planning and 3D printing is gaining popularity in veterinary oromaxillofacial surgery and are viable tools for the most basic to the most complex cases. These techniques can provide the surgeon with improved visualization and, thus, understanding of the patients' 3D anatomy. Virtual surgical planning is feasible in a clinical setting and may decrease surgical time and increase surgical accuracy. For example, pre-operative implant contouring on a 3D-printed model can save time during surgery; 3D-printed patient-specific implants and surgical guides help maintain normocclusion after mandibular reconstruction; and the presence of a haptic model in the operating room can improve surgical precision and safety. However, significant time and financial resources may need to be allocated for planning and production of surgical guides and implants. The objectives of this manuscript are to provide a description of the methods involved in virtual surgical planning and 3D printing as they apply to veterinary oromaxillofacial surgery and to highlight these concepts with the strategic use of examples. In addition, the advantages and disadvantages of the methods as well as the required software and equipment will be discussed.

Virtual Surgical Planning in Free Tissue Transfer for Orbito-Maxillary Reconstruction

Since its introduction, virtual surgical planning (VSP) has been rapidly adopted as a part of reconstructive surgeon's armamentarium. VSP allows reconstructive surgeons to simulate resection, plan osteotomies, and design custom plates. These unique advantages have been especially beneficial for head and neck reconstructive surgeons as there is small room for error and high technical demand in head and neck reconstruction. Despite its popularity, most surgeons have limited experience in using VSP for orbito-maxillary reconstruction as tumors that involve the midface are relatively rare compared with other head and neck oncologic defects. In our institution, we routinely use VSP for orbito-maxillary reconstruction using free fibula flap to provide support for orbit, to restore normal dental occlusion, and to restore midface projection. In this chapter, we will discuss the role of virtual surgical planning and our algorithmic approach of performing orbito-maxillary reconstruction using free tissue transfer.

Computer-Assisted Microvascular Free Flap Reconstruction and Implant Rehabilitation of the Maxilla-Treatment of a Rare Post-orthognathic Complication

Orthognathic surgery is generally a safe and predictable procedure. Major postoperative complications are rare and often non-life threatening. An example of a rare complication associated with the LeFort I osteotomy is avascular necrosis of the maxilla (ANM). While cases of ANM have been described in the literature, the majority involves only a portion or segment of the maxillary complex and is commonly treated with conservative measures such as strict oral hygiene, hyperbaric oxygen therapy and local debridement. Occasionally, larger segments of osteonecrosis may require extensive reconstruction such as bone grafting with local soft tissue flaps. Here, we present a patient that underwent a single-stage microvascular free tissue reconstruction with concomitant placement of dental implants and a patient-specific implant (PSI) for post-orthognathic ANM.

Management of Bilateral Condylar Fractures in an Edentulous Patient with Atrophic Mandible Using CADCAM Technology

Purpose

The objective of this article is to report the case of an edentulous patient with a diagnosis of bilateral condylar fracture, who was treated using virtual planning.

Methods

CAD/CAM technology was used for the design and manufacture of a Gunning splint, which was employed for open reduction of the right fracture and closed management of the left side.

Results

The reduction of the right condylar fracture projected in the planning was achieved, as well as the return of the vertical dimension and the restoration of function, after 28 months of observation.

Conclusion

In the case of total edentulism, the lack of occlusal guidance and bone atrophy are important variables to consider; however, tools such as CAD/CAM technology can be used to take more predictable treatment decisions and facilitate the execution of the procedures.

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.

Virtual Surgical Planning and 3D Printing in Veterinary Dentistry and Oromaxillofacial Surgery

Virtual surgical planning and three-dimensional (3D) printing are preoperative processes requiring the acquisition of high-quality imaging data. A surgical treatment plan is created and rehearsed virtually as the operator manipulates the 3D images of the patient within the software. When the operator is satisfied with the plan, including anticipated osteotomies, tumor excision margins, and reconstruction options, physical 3D prints can be produced. This article introduces the reader to the basic concepts involved in virtual surgical planning and 3D printing as well as their implementation in veterinary oromaxillofacial surgery.

Virtual Surgical Planning of Deep Circumflex Iliac Artery Flap for Midface Reconstruction

Objective

Midface reconstruction is challenging for functional and esthetic reasons. The present study analyzed the effect of virtual surgical planning (VSP) of the deep circumflex iliac artery (DCIA) flap for midface reconstruction.

Patients and Methods

Thirty-four patients who underwent midface reconstruction with the DCIA flap were included in this retrospective study. Of the 34 patients, 16 underwent preoperative VSP, which used a three-dimensionally printed surgical guide, computer-assisted navigation system, and pre-bent titanium implants to transfer VSP into real-world surgery. The other 18 patients underwent traditional midface reconstruction. The following were compared between the two groups: bony contact rate in the buttress region (BCR), dental arch reconstruction rate (DAR), surgical approach, position of vascular anastomosis, and dental implantation rate. The independent-samples t-test and Fisher's exact test were used for analysis. P < 0.05 was considered statistically significant.

Results

In total, 12 males and 22 females were included in this study. All patients underwent midface reconstruction using the DCIA flap at the same institution. The median age of patients was 33 years (range: 16-68 years). The average BCR and DAR values in the VSP group were 59.4% ± 27.9% and 87.5% ± 18.9%, respectively, which were significantly higher compared with the non-VSP group (P = 0.049 and P = 0.004, respectively). The dental implantation rate in the VSP group (50.0%) was significantly higher compared with the non-VSP group (11.1%; P = 0.023). The intraoral approach for tumor ablation and vascular anastomosis was the most frequent choice in both groups. There was no significant difference between the two groups. All patients were satisfied with facial symmetry postoperatively.

Conclusions

VSP could effectively augment the effect of midface reconstruction with the DCIA flap. Stronger bone contact in the buttress region and higher DAR provide more opportunity for dental implantation, which might be the best solution to improve masticatory function in patients with midface defects.

Virtual Analysis of Segmental Bimaxillary Surgery: A Validation Study

PURPOSE

Three-dimensional (3D) assessment of orthognathic surgery is often time consuming, relies on manual re-identification of anatomical landmarks or is limited to non-segmental osteotomies. The purpose of the present study was to propose and validate an automated approach for 3D assessment of the accuracy and postoperative outcome of segmental bimaxillary surgery.

METHODS

A semi-automatic approach was developed and validated for virtual surgical analysis (VSA) of segmental bimaxillary surgery using a pair of pre- and postoperative (2 weeks) cone-beam computerized tomography (CBCT) scans. The output of the VSA, the accuracy of the surgical outcome, was calculated as 3D translational and rotational differences between the planned and postoperative movements of the individual bone segments. To evaluate the reliability of the proposed VSA, intra-class correlation coefficients (ICC) were calculated at a 95% confidence interval on measurements of 2 observers. The VSA was deemed reliable if the ICC was excellent (> 0.80) and the absolute difference of the repeated intra- and inter-observer translational and rotational measurements were significantly lower (p < 0.05) than a hypothesized clinical relevant threshold of 1 voxel (0.45 mm) and 1 degree, respectively.

RESULTS

A total of 10 subjects (6 male; 4 women; mean age 24.4 years) with skeletal class 2 and 3, who underwent segmental bimaxillary surgery, 3-piece Le Fort I, bilateral sagittal split osteotomy and genioplasty, were recruited. The intra- and inter-observer reliability was excellent, ICC range [0.96 - 1.00]. The range of the mean absolute difference of the repeated intra- and inter-observer translational and rotational measurements were [0.07 mm (0.05) - 0.20 mm (0.19)] and [0.11˚ (0.08) - 0.63˚ (0.42)], respectively. This was significantly lower than the hypothesized clinical relevant thresholds (P < .001).

CONCLUSION

The validation showed that the VSA has excellent reliability for quantitative assessment of the postoperative outcome and accuracy of segmental bimaxillary surgery.

Imaging in Oral and Maxillofacial Surgery

The scope of oral and maxillofacial surgery treatment and care is very broad, from dentoalveolar surgery, to pathology and reconstruction, to treatment of craniofacial deformities. The effective surgical treatment of patients requires appropriate and accurate diagnostic imaging. The various imaging modalities used in oral and maxillofacial surgery are typically for diagnostic and treatment planning purposes. With the improvements of three-dimensional imaging and software programs, surgical treatment and care have been enhanced with patient-specific guides, hardware, and implants. This article discusses the various imaging modalities used for a variety of typical oral and maxillofacial surgery procedures.

Comparisons of orthodontic residents' performance and attitudes using 2D, 3D, and virtual reality surgical simulation methods

PURPOSE

Advances in virtual reality technology for surgical simulation methods may improve diagnosis and treatment planning of complex orthognathic surgery cases. The objectives were to assess orthodontic residents' performance and attitudes when treatment planning orthognathic surgery cases using two-dimensional (2D) digital, three-dimensional (3D) digital, and virtual reality (VR) surgical simulations.

METHODS

The study had a mixed methods study design involving 20 graduate orthodontic residents. Their previous experiences, confidence, and competence with orthodontic diagnosis and surgical treatment planning were assessed with a baseline survey. Each resident completed 2D, 3D, and VR treatment planning and simulation tasks in a randomized order and recorded their diagnosis, objectives, treatment plan, and special surgical concerns for each case using a treatment planning worksheet. The worksheets were scored and quantitative data were analyzed. Attitudinal responses to the simulation experience were captured with a post-survey and interview.

RESULTS

The number of total prescribed surgical movements was greater for 3D and VR simulation methods (p = 0.001). There were no differences in the overall total written treatment plan analysis score among the three surgical simulation tasks. Participants took longer to complete the VR and 3D tasks (p < 0.001) and asked more questions regarding manipulation (p < 0.001) and software features (p < 0.002) for higher fidelity tools. Analysis of qualitative feedback showed positive attitudes toward higher fidelity tools with regard to visualization, manipulation, and enjoyment of the task.

CONCLUSIONS

The results demonstrate that simulation methods of increased fidelity (3D and VR) are appropriate alternatives to 2D conventional orthognathic surgical simulation methods when combined with traditional records. Qualitative feedback confirms residents' readiness to adopt VR simulation. However, comprehensive training is needed to increase familiarity and comfort with using the new technology.

Reconstruction and optimization of the 3D geometric anatomy structure model for subject-specific human knee joint based on CT and MRI images

BACKGROUND:

Nowadays, the total knee arthroplasty (TKA) technique plays an important role in surgical treatment for patients with severe knee osteoarthritis (OA). However, there are still several key issues such as promotion of osteotomy accuracy and prosthesis matching degree that need to be addressed.

OBJECTIVE:

It is significant to construct an accurate three-dimensional (3D) geometric anatomy structure model of subject-specific human knee joint with major bone and soft tissue structures, which greatly contributes to obtaining personalized osteotomy guide plate and suitable size of prosthesis.

METHODS:

Considering different soft tissue structures, magnetic resonance imaging (MRI) scanning sequences involving two-dimensional (2D) spin echo (SE) sequence T1 weighted image (T1WI) and 3D SE sequence T2 weighted image (T2WI) fat suppression (FS) are selected. A 3D modeling methodology based on computed tomography (CT) and two sets of MRI images is proposed.

RESULTS:

According to the proposed methods of image segmentation and 3D model registration, a novel 3D knee joint model with high accuracy is finally constructed. Furthermore, remeshing is used to optimize the established model by adjusting the relevant parameters.

CONCLUSIONS:

The modeling results demonstrate that reconstruction and optimization model of 3D knee joint can clearly and accurately reflect the key characteristics, including anatomical structure and geometric morphology for each component.

Cold Ablation Robot-Guided Laser Osteotome (CARLO®): From Bench to Bedside

Background: In order to overcome the geometrical and physical limitations of conventional rotating and piezosurgery instruments used to perform bone osteotomies, as well as the difficulties in translating digital planning to the operating room, a stand-alone robot-guided laser system has been developed by Advanced Osteotomy Tools, a Swiss start-up company. We present our experiences of the first-in-man use of the Cold Ablation Robot-guided Laser Osteotome (CARLO^®). Methods: The CARLO^® device employs a stand-alone 2.94-µm erbium-doped yttrium aluminum garnet (Er:YAG) laser mounted on a robotic arm. A 19-year-old patient provided informed consent to undergo bimaxillary orthognathic surgery. A linear Le Fort I midface osteotomy was digitally planned and transferred to the CARLO^® device. The linear part of the Le Fort I osteotomy was performed autonomously by the CARLO^® device under direct visual control. All pre-, intra-, and postoperative technical difficulties and safety issues were documented. Accuracy was analyzed by superimposing pre- and postoperative computed tomography images. Results: The CARLO^® device performed the linear osteotomy without any technical or safety issues. There was a maximum difference of 0.8 mm between the planned and performed osteotomies, with a root-mean-square error of 1.0 mm. The patient showed normal postoperative healing with no complications. Conclusion: The newly developed stand-alone CARLO^® device could be a useful alternative to conventional burs, drills, and piezosurgery instruments for performing osteotomies. However, the technical workflow concerning the positioning and fixation of the target marker and the implementation of active depth control still need to be improved. Further research to assess safety and accuracy is also necessary, especially at osteotomy sites where direct visual control is not possible. Finally, cost-effectiveness analysis comparing the use of the CARLO^® device with gold-standard surgery protocols will help to define the role of the CARLO^® device in the surgical landscape.