Time matters – Differences between computer-assisted surgery and conventional planning in cranio-maxillofacial surgery: A systematic review and meta-analysis

Efficiency and Applicability of Virtual Surgical Planning in Maxillofacial and Mandibular Bone Reconstruction: A Narrative Review

Background: Facial structures are critical to aesthetics and function. Deformities can cause significant problems. Advances in surgical techniques, including three-dimensional (3D) computer simulation and virtual surgical planning (VSP), have improved outcomes. VSP accurately predicts surgical outcomes, revolutionizing facial reconstruction. This article reviews VSP in facial bone reconstruction, highlighting its advantages and accuracy over traditional methods. Methods: A systematic search using Medline (PubMed), Web of Science, Scopus, and Google Scholar revealed 1645 articles that addressed the topic of this study. Results: The systematic search yielded 64 articles that were highly relevant to the study objective, underscoring the critical importance of virtual surgical planning (VSP) in enhancing surgical precision and patient satisfaction. VSP has become a key player in improving surgical interventions and reducing complications, reinforcing its role as the preferred method in modern reconstructive surgery and thus improving functional and aesthetic outcomes, significantly enhancing patient satisfaction, and ensuring accurate interpretation of treatment plans. When compared to traditional surgical planning (TSP), VSP offers increased accuracy, shorter operating times, and superior aesthetic outcomes. Conclusions: VSP has been shown to effectively manage the complex challenges of facial anatomy and has significantly enhanced the planning and execution of reconstructive surgeries. This has been achieved by leveraging advanced imaging and computer-aided design.

Effectiveness of Traditional and Virtual Surgical Planning in Orthognathic Surgery: A Systematic Review and Meta-Analysis

Orthognathic surgery, which corrects jaw deformities, requires meticulous planning to achieve optimal functional and aesthetic outcomes. Traditional surgical planning (TSP) relies on manual methods, whereas virtual surgical planning (VSP) uses computer-assisted simulations that may enhance accuracy and efficiency. Therefore, we conducted a systematic review to evaluate the effectiveness of VSP compared to TSP for orthognathic surgery. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and registered the protocol in the Prospective Register of Systematic Reviews (CRD42024618614). We searched electronic databases for studies comparing VSP and TSP. Two independent reviewers performed screening and data extraction. We assessed quality using the Cochrane Risk of Bias 2 (RoB 2) tool. We calculated the standardized mean difference (SMD) as the summary measure and used a random-effects model, considering p < 0.05 as statistically significant. We performed analyses using Review Manager (RevMan) version 5.3 (Cochrane Collaboration, London, UK). We included 10 qualitative synthesis and meta-analysis studies, evaluating data from 474 patients, of whom 244 underwent TSP and 230 underwent VSP. Included studies showed moderate to low risk of bias. We evaluated effectiveness in terms of planning time, surgical time, horizontal measurements, vertical measurements, and accuracy indicators for predicting outcomes. Meta-analysis revealed reduced planning time (SMD = 3.19 (-5.74 to 0.64)) and surgical time (SMD = -0.42 (-1.32 to 0.49)) with VSP, as well as differences in horizontal (SMD = -0.39 (-0.73 to 0.05)) and vertical measurements (SMD = -0.20 (-0.54 to 0.13)), and in accuracy indicators (SNA0: SMD = -0.15 (-0.46 to 0.16); SNB0: SMD = 0.53 (-0.82 to 1.87)). SNA0 represents the angle formed by sella (S), nasion (N), and point A (A), and SNB0 represents the angle formed by sella (S), nasion (N), and point B (B). The funnel plot showed no evidence of publication bias. VSP reduced planning and surgical times and predicted facial outcomes more accurately than TSP. These findings suggest that VSP can be an effective alternative to TSP in orthognathic surgeries.

Deep learning segmentation of mandible with lower dentition from cone beam CT

OBJECTIVES

This study aimed to train a 3D U-Net convolutional neural network (CNN) for mandible and lower dentition segmentation from cone-beam computed tomography (CBCT) scans.

METHODS

In an ambispective cross-sectional design, CBCT scans from two hospitals (2009-2019 and 2021-2022) constituted an internal dataset and external validation set, respectively. Manual segmentation informed CNN training, and evaluations employed Dice similarity coefficient (DSC) for volumetric accuracy. A blinded oral maxillofacial surgeon performed qualitative grading of CBCT scans and object meshes. Statistical analyses included independent t-tests and ANOVA tests to compare DSC across patient subgroups of gender, race, body mass index (BMI), test dataset used, age, and degree of metal artifact. Tests were powered for a minimum detectable difference in DSC of 0.025, with alpha of 0.05 and power level of 0.8.

RESULTS

648 CBCT scans from 490 patients were included in the study. The CNN achieved high accuracy (average DSC: 0.945 internal, 0.940 external). No DSC differences were observed between test set used, gender, BMI, and race. Significant differences in DSC were identified based on age group and the degree of metal artifact. The majority (80%) of object meshes produced by both manual and automatic segmentation were rated as acceptable or higher quality.

CONCLUSION

We developed a model for automatic mandible and lower dentition segmentation from CBCT scans in a demographically diverse cohort including a high degree of metal artifacts. The model demonstrated good accuracy on internal and external test sets, with majority acceptable quality from a clinical grader.

Accuracy of 3D Virtual Surgical Planning Compared to the Traditional Two-Dimensional Method in Orthognathic Surgery: A Literature Review

With the innovation of three-dimensional imaging and printing techniques, computer-aided surgical planning, also known as virtual surgical planning (VSP), has revolutionized orthognathic surgery. Designing and manufacturing patient-specific surgical guides using three-dimensional printing techniques to improve surgical outcomes is now possible. This article presents an overview of VSP in orthognathic surgery and discusses the advantages and accuracy of this technique compared to traditional surgical planning (TSP). A PubMed and Google Scholar search was conducted to find relevant articles published over the past 10 years. The search revealed 2,581 articles, of which 36 full-text articles specifically addressed the topic of this study. The review concludes that VSP in orthognathic surgery provides optimal functional and aesthetic results, enhances patient satisfaction, ensures precise translation of the treatment plan, and facilitates intraoperative manipulation.

Reliabilities of three methods used to evaluate computer-assisted mandibular reconstructions using free fibula flaps

Objective

This study compared the reliabilities of three different methods used to calculate surgical deviations after mandibular reconstructions using free fibular flaps.

Study design

This retrospective study involved 35 patients who underwent computer-assisted mandibular reconstructions using free fibula flaps. The deviations between the virtual surgical plans and the postoperative results were independently analyzed by two researchers using three distinct methods. In Method A, the fibular axis, the center of gravity, and the osteotomy plane served as landmarks when measuring surgical deviations. In Methods B and C, manually designated points were used to measure errors in the fibular length and intersegmental angle. The primary outcome variables were the intraclass correlation coefficients (ICCs) that revealed the inter-rater agreements for all three methods.

Results

The use of Method A was associated with good agreement in terms of the fibular length deviation (ICC = 0.765) and intersegmental angle (ICC = 0.897); both were higher than those afforded by Methods B (ICC = 0.158 and 0.108) and C (ICC = 0.406 and 0.463). The measurements of the fibular transfer osteotomy deviation (ICC = 0.888), linear deviation (0.926), and angular deviation (0.958) were very reliable.

Conclusions

Method A afforded the highest reliability in clinical practice when evaluating surgical deviations after mandibular reconstruction using fibular flaps.

A Stage-Wise Residual Attention Generation Adversarial Network for Mandibular Defect Repairing and Reconstruction

Surgical reconstruction of mandibular defects is a clinical routine manner for the rehabilitation of patients with deformities. The mandible plays a crucial role in maintaining the facial contour and ensuring the speech and mastication functions. The repairing and reconstruction of mandible defects is a significant yet challenging task in oral-maxillofacial surgery. Currently, the mainly available methods are traditional digitalized design methods that suffer from substantial artificial operations, limited applicability and high reconstruction error rates. An automated, precise, and individualized method is imperative for maxillofacial surgeons. In this paper, we propose a Stage-wise Residual Attention Generative Adversarial Network (SRA-GAN) for mandibular defect reconstruction. Specifically, we design a stage-wise residual attention mechanism for generator to enhance the extraction capability of mandibular remote spatial information, making it adaptable to various defects. For the discriminator, we propose a multi-field perceptual network, consisting of two parallel discriminators with different perceptual fields, to reduce the cumulative reconstruction errors. Furthermore, we design a self-encoder perceptual loss function to ensure the correctness of mandibular anatomical structures. The experimental results on a novel custom-built mandibular defect dataset demonstrate that our method has a promising prospect in clinical application, achieving the best Dice Similarity Coefficient (DSC) of 94.238% and 95% Hausdorff Distance (HD95) of 4.787.

Virtual surgical planning in orthognathic surgery: a dental hospital's 10-year experience

PURPOSE

The primary objective of this study was to evaluate how the utilization of virtual surgical planning (VSP) and the epidemiological profile of patients undergoing orthognathic surgery (OGS) have changed in the past decade.

METHODS

The records of patients who had undergone orthognathic surgery at a national dental hospital were reviewed. Trends in VSP, epidemiological data, presentation of dentofacial deformity, and management details were recorded.

RESULTS

A total of 1184 patients were included in this study. The majority of the patients seeking treatment in this dental hospital were young Chinese adults with dentofacial deformities requiring bimaxillary surgeries. Most patients presented with a skeletal Class III pattern (79.0%), and asymmetry was diagnosed in 80.8% of all cases.

CONCLUSION

There was an initial slow pick-up rate for VSP, but this rapidly increased to a high adoption rate of 98.7-100% between 2019 and 2021. Together with an increasing body of evidence suggesting greater accuracy in VSP, utilization in this technology can be enhanced with greater familiarity with the technology and improvements in the VSP services.

Evaluating the benefit of virtual surgical planning on bony union rates in head and neck reconstructive surgery

OBJECTIVES

Virtual surgical planning (VSP) has gained acceptance because of its benefits in obtaining adequate resection, achieving cephalometric accuracy, and reducing operative time. The aim of this study is to compare the rate of union between VSP and free-hand surgery (FHS), identify predictors of non-union and evaluate the difference in operative time.

METHODS

Post-operative CT were retrospectively reviewed for 123 patients who underwent maxillary or mandibular reconstruction between 2014 and 2021 using either VSP or FHS. Each apposition was graded as complete, partial or non-union. The rate of union, risk difference and inter-rater reliability were calculated. The difference in operative time was assessed. Predictors of non-union were identified using logistic regression.

RESULTS

A total of 326 appositions were graded (VSP n = 150; FHS n = 176). The rates of complete and partial union were higher with VSP than FHS (74.7% vs. 65.3%; 18% vs. 15.9%, respectively, p = 0.01). Non-union was found at a higher rate with FHS than with VSP (18.7% vs. 7.3%). The non-union risk difference was 11.4. FHS, major complications and apposition at the native bone were predictors of non-union (OR 2.9, p = 0.02; OR 3.4, p = 0.01; OR 2.5, p = 0.05, respectively). The mean surgical time was shorter with VSP than with FHS (265.3 vs. 381.5 min, p < 0.001). The inter-rater agreement was high (k = 0.85; ICC = 0.86).

CONCLUSION

VSP demonstrated significantly higher bony union rates and shorter operative time. FHS, development of major complications and apposition with native bone correlated with non-union.

Digitalization in Cranial Reconstruction: Revolutionizing Precision and Innovation

Cranioplasty for cranial defects can be complex and challenging in composite defects. The intricate 3D structure of the craniofacial skeleton poses various difficulties encountered in surgical reconstruction. The continuous progress in computer-aided design and computer-aided manufacturing design, and fabrication technology has led to a growing array of applications for visual analog scale and 3D printing in craniofacial surgery, encompassing preoperative assessment, the creation of cutting guides, and the development of custom implants and stereolithographic models. Within this review, the authors detail the present and developing applications of virtual surgical planning, 3D bioprinting, augmented reality, and virtual reality in craniofacial reconstruction.

Single-Splint, 2-Jaw Orthognathic Surgery for Correction of Facial Asymmetry: 3-Dimensional Planning and Surgical Execution

Three-dimensional (3D) planning of orthognathic surgery (OGS) improves the treatment of facial asymmetry and malocclusion, but no consensus exists among clinicians regarding technical details. This study verified the consistency of authors' workflow and strategies between 3D planning and surgical execution for facial asymmetry. This retrospective study recruited consecutive patients (n=54) with nonsyndromic facial asymmetry associated with malocclusion. The stepwise workflow included orthodontic treatment, 3D imaging-based evaluation, planning, and transferring the virtual of single-splint 2-jaw OGS to actual surgery in all patients. Seven landmark-based measurements were selected for postoperative assessment of facial symmetry. Fifty patients had no anesthetic/surgical-related episode and procedure-related complications. Others experienced wound infection (n=1), transient TMJ discomfort (n=1), and facial numbness (n=3). Two cases had minor residual asymmetry (cheek and chin, respectively), but did not request revisionary bone or soft tissue surgery. Comparisons between the planned and postoperative 3D images with quantitative measurement revealed acceptable outcome data. The results showed a significant increase in facial symmetry at 7 landmark-based postoperative measurements for both male and female. This 3D-assisted pathway of OGS permitted achievement of consistent satisfactory results in managing facial asymmetry, with low rate of complications and secondary management.

Virtual Surgical Planning for Patients with Skeletal-Dental and Obstructive Sleep Apnea Syndrome

The integration of virtual surgical planning (VSP) for the treatment of skeletal, dental, and facial abnormalities and obstructive sleep apnea (OSA) with maxillofacial surgery has catapulted surgical planning. Although reported for treating skeletal-dental abnormalities and dental implant surgery, a paucity of knowledge existed reporting the feasibility and resultant outcome measures when VSP was employed for planning maxillary and mandibular surgery for OSA patients. The surgery-first approach is at the forefront of advancing maxillofacial surgery. Case series reporting success with the surgery-first approach for patients with skeletal-dental and sleep apnea patients have been reported. In sleep apnea patients, clinically significant reductions in apnea-hypopnea index and improvement of low oxyhemoglobin saturation have been achieved. More so, significant improvement in the posterior airway space at the occlusal and mandibular planes were achieved, while preserving aesthetic norms as measured by tooth to lip measurements. VSP is a feasible tool used for predicting surgical outcome measures in maxillomandibular advancement surgery for patients with skeletal, dental, facial, and OSA derangements.

Advantages of a Training Course for Surgical Planning in Virtual Reality for Oral and Maxillofacial Surgery: Crossover Study

BACKGROUND

As an integral part of computer-assisted surgery, virtual surgical planning (VSP) leads to significantly better surgery results, such as for oral and maxillofacial reconstruction with microvascular grafts of the fibula or iliac crest. It is performed on a 2D computer desktop screen (DS) based on preoperative medical imaging. However, in this environment, VSP is associated with shortcomings, such as a time-consuming planning process and the requirement of a learning process. Therefore, a virtual reality (VR)-based VSP application has great potential to reduce or even overcome these shortcomings due to the benefits of visuospatial vision, bimanual interaction, and full immersion. However, the efficacy of such a VR environment has not yet been investigated.

OBJECTIVE

This study aimed to demonstrate the possible advantages of a VR environment through a substep of VSP, specifically the segmentation of the fibula (calf bone) and os coxae (hip bone), by conducting a training course in both DS and VR environments and comparing the results.

METHODS

During the training course, 6 novices were taught how to use a software application in a DS environment (3D Slicer) and in a VR environment (Elucis) for the segmentation of the fibula and os coxae, and they were asked to carry out the maneuvers as accurately and quickly as possible. Overall, 13 fibula and 13 os coxae were segmented for each participant in both methods (VR and DS), resulting in 156 different models (78 fibula and 78 os coxae) per method (VR and DS) and 312 models in total. The individual learning processes in both environments were compared using objective criteria (time and segmentation performance) and self-reported questionnaires. The models resulting from the segmentation were compared mathematically (Hausdorff distance and Dice coefficient) and evaluated by 2 experienced radiologists in a blinded manner.

RESULTS

A much faster learning curve was observed for the VR environment than the DS environment (β=.86 vs β=.25). This nearly doubled the segmentation speed (cm³/min) by the end of training, leading to a shorter time (P<.001) to reach a qualitative result. However, there was no qualitative difference between the models for VR and DS (P=.99). The VR environment was perceived by participants as more intuitive and less exhausting, and was favored over the DS environment.

CONCLUSIONS

The more rapid learning process and the ability to work faster in the VR environment could save time and reduce the VSP workload, providing certain advantages over the DS environment.

Accuracy of Orthognathic Surgical Planning using Three-dimensional Virtual Techniques compared with Conventional Two-dimensional Techniques: a Systematic Review

Objectives

The objective was to assess the accuracy of orthognathic surgical planning using three-dimensional virtual planning compared with conventional two-dimensional planning.

Material and Methods

MEDLINE (PubMed), Embase and Cochrane Library search combined with hand-search of relevant journals was conducted to identify randomized controlled trials (RCTs) published in English through August 2^nd, 2022. Primary outcomes included postsurgical accuracy of hard and soft tissue. Secondary outcomes included treatment planning time, intraoperative time, intraoperative blood loss, complications, financial expenses, and patient-reported outcome measures (PROMs). Quality and risk-of-bias assessment were evaluated by Cochrane risk of bias tool and GRADE system.

Results

Seven RCTs characterised by low, high, and unclear risk of bias fulfilled inclusion criteria. Included studies disclosed conflicting results regarding accuracy of hard and soft tissue as well as treatment planning time. The intraoperative time was shortened, and financial expenses were increased with three-dimensional virtual surgical planning (TVSP), while no planning-related complications were revealed. Comparable improvement in PROMs were reported with TVSP and two-dimensional planning.

Conclusions

Future orthognathic surgical planning will indisputable be performed by three-dimensional virtual planning. The financial expenses, treatment planning time, and intraoperative time will therefore probably decrease due to further development of three-dimensional virtual planning techniques. The hard and soft tissue accuracy between planned position and achieved surgical outcome seems to be improved by three-dimensional virtual planning compared with two-dimensional planning, although results are inconsistent. Further development of three-dimensional virtual planning involving cutting guides and patient-specific osteosynthesis plates are therefore needed to improve the accuracy of orthognathic surgical planning.

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.

Standardized and axially vascularized calcium phosphate-based implants for segmental mandibular defects: A promising proof of concept

The reconstruction of massive segmental mandibular bone defects (SMDs) remains challenging even today; the current gold standard in human clinics being vascularized bone transplantation (VBT). As alternative to this onerous approach, bone tissue engineering strategies have been widely investigated. However, they displayed limited clinical success, particularly in failing to address the essential problem of quick vascularization of the implant. Although routinely used in clinics, the insertion of intrinsic vascularization in bioengineered constructs for the rapid formation of a feeding angiosome remains uncommon. In a clinically relevant model (sheep), a custom calcium phosphate-based bioceramic soaked with autologous bone marrow and perfused by an arteriovenous loop was tested to regenerate a massive SMD and was compared to VBT (clinical standard). Animals did not support well the VBT treatment, and the study was aborted 2 weeks after surgery due to ethical and animal welfare considerations. SMD regeneration was successful with the custom vascularized bone construct. Implants were well osseointegrated and vascularized after only 3 months of implantation and totally entrapped in lamellar bone after 12 months; a healthy yellow bone marrow filled the remaining space. STATEMENT OF SIGNIFICANCE: Regenerative medicine struggles with the generation of large functional bone volume. Among them segmental mandibular defects are particularly challenging to restore. The standard of care, based on bone free flaps, still displays ethical and technical drawbacks (e.g., donor site morbidity). Modern engineering technologies (e.g., 3D printing, digital chain) were combined to relevant surgical techniques to provide a pre-clinical proof of concept, investigating for the benefits of such a strategy in bone-related regenerative field. Results proved that a synthetic-biologics-free approach is able to regenerate a critical size segmental mandibular defect of 15 cm³ in a relevant preclinical model, mimicking real life scenarii of segmental mandibular defect, with a full physiological regeneration of the defect after 12 months.

Automated segmentation of head CT scans for computer-assisted craniomaxillofacial surgery applying a hierarchical patch-based stack of convolutional neural networks

PURPOSE

Computer-assisted techniques play an important role in craniomaxillofacial surgery. As segmentation of three-dimensional medical imaging represents a cornerstone for these procedures, the present study was aiming at investigating a deep learning approach for automated segmentation of head CT scans.

METHODS

The deep learning approach of this study was based on the patchwork toolbox, using a multiscale stack of 3D convolutional neural networks. The images were split into nested patches using a fixed 3D matrix size with decreasing physical size in a pyramid format of four scale depths. Manual segmentation of 18 craniomaxillofacial structures was performed in 20 CT scans, of which 15 were used for the training of the deep learning network and five were used for validation of the results of automated segmentation. Segmentation accuracy was evaluated by Dice similarity coefficient (DSC), surface DSC, 95% Hausdorff distance (95HD) and average symmetric surface distance (ASSD).

RESULTS

Mean for DSC was 0.81 ± 0.13 (range: 0.61 [mental foramen] - 0.98 [mandible]). Mean Surface DSC was 0.94 ± 0.06 (range: 0.87 [mental foramen] - 0.99 [mandible]), with values > 0.9 for all structures but the mental foramen. Mean 95HD was 1.93 ± 2.05 mm (range: 1.00 [mandible] - 4.12 mm [maxillary sinus]) and for ASSD, a mean of 0.42 ± 0.44 mm (range: 0.09 [mandible] - 1.19 mm [mental foramen]) was found, with values < 1 mm for all structures but the mental foramen.

CONCLUSION

In this study, high accuracy of automated segmentation of a variety of craniomaxillofacial structures could be demonstrated, suggesting this approach to be suitable for the incorporation into a computer-assisted craniomaxillofacial surgery workflow. The small amount of training data required and the flexibility of an open source-based network architecture enable a broad variety of clinical and research applications.

The role of computer aided design/computer assisted manufacturing (CAD/CAM) and 3- dimensional printing in head and neck oncologic surgery: A review and future directions

Microvascular free flap reconstruction has remained the standard of care in reconstruction of large tissue defects following ablative head and neck oncologic surgery, especially for bony structures. Computer aided design/computer assisted manufacturing (CAD/CAM) and 3-dimensionally (3D) printed models and devices offer novel solutions for reconstruction of bony defects. Conventional free hand techniques have been enhanced using 3D printed anatomic models for reference and pre-bending of titanium reconstructive plates, which has dramatically improved intraoperative and microvascular ischemia times. Improvements led to current state of the art uses which include full virtual planning (VP), 3D printed osteotomy guides, and patient specific reconstructive plates, with advanced options incorporating dental rehabilitation and titanium bone replacements into the primary surgical plan through use of these tools. Limitations such as high costs and delays in device manufacturing may be mitigated with in house software and workflows. Future innovations still in development include printing custom prosthetics, 'bioprinting' of tissue engineered scaffolds, integration of therapeutic implants, and other possibilities as this technology continues to rapidly advance. This review summarizes the literature and serves as a summary guide to the historic, current, advanced, and future possibilities of 3D printing within head and neck oncologic surgery and bony reconstruction. This review serves as a summary guide to the historic, current, advanced, and future roles of CAD/CAM and 3D printing within the field of head and neck oncologic surgery and bony reconstruction.

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.

Microtia Ear Reconstruction with Patient-Specific 3D Models-A Segmentation Protocol

(1) Background: In recent years, three-dimensional (3D) templates have replaced traditional two-dimensional (2D) templates as visual guides during intra-operative carving of the autogenous cartilage framework in microtia reconstruction. This study aims to introduce a protocol of the fabrication of patient-specific, 3D printed and sterilizable auricular models for autogenous auricular reconstruction. (2) Methods: The patient's unaffected ear was captured with a high-resolution surface 3D scan (Artec Eva) and post-processed in order to obtain a clean surface model (STL format). In the next step, the ear was digitally mirrored, segmented and separated into its component auricle parts for reconstruction. It was disassembled into helix, antihelix, tragus and base and a physical model was 3D printed for each part. Following this segmentation, the cartilage was carved in the operating room, based on the models. (3) Results: This segmentation technique facilitates the modeling and carving of the scaffold, with adequate height, depth, width and thickness. This reduces both the surgical time and the amount of costal cartilage used. (4) Conclusions: This segmentation technique uses surface scanning and 3D printing to produce sterilizable and patient-specific 3D templates.

Clinical Outcomes and Cost Analysis of Fibula Free Flaps: A Retrospective Comparison of CAD/CAM versus Conventional Technique

(1) Background: A decrease in operative time can not only improve patient outcomes through a reduction in the risk of developing complications but can also result in cost savings. The aim of this study is to determine whether there an intraoperative time gain can be achieved by using the preoperative virtual planning of mandibular reconstruction using a free fibula flap compared with freehand plate bending and osteotomies. (2) Methods: A retrospective comparative study was carried out in the Oral and Maxillofacial Department of La Paz University Hospital, Madrid, Spain. The study compared 18 patients in the CAD/CAM group with 19 patients in the conventional freehand group. A comparison was made between the total surgical time, the comorbidities, and the hospital stay. The resource consumption was estimated using a cost analysis. (3) Results: Although CAD/CAM was a statistically more expensive procedure in the perioperative phase, no significant differences were observed in total health care costs between the two groups. There was a non-significant trend towards an increase in complications with conventional reconstruction plates compared to patient-specific plates (PSI). (4) Conclusions: CAD/CAM technology and a 3D printed cutting guide offer a significantly shorter surgical time, which is associated with a reduction in hospital days, PACU days, and complications. The cost of CAD/CAM technology is comparable to that of the conventional freehand technique.

Current and Novel Treatment Options for OSA

Obstructive sleep apnoea is a challenging medical problem due to its prevalence, its impact on quality of life and performance in school and professionally, the implications for risk of accidents, and comorbidities and mortality. Current research has carved out a broad spectrum of clinical phenotypes and defined major pathophysiological components. These findings point to the concept of personalised therapy, oriented on both the distinct clinical presentation and the most relevant pathophysiology in the individual patient. This leads to questions of whether sufficient therapeutic options other than positive airway pressure (PAP) alone are available, for which patients they may be useful, if there are specific indications for single or combined treatment, and whether there is solid scientific evidence for recommendations. This review describes our knowledge on PAP and non-PAP therapies to address upper airway collapsibility, muscle responsiveness, arousability and respiratory drive. The spectrum is broad and heterogeneous, including technical and pharmaceutical options already in clinical use or at an advanced experimental stage. Although there is an obvious need for more research on single or combined therapies, the available data demonstrate the variety of effective options, which should replace the unidirectional focus on PAP therapy.

The analysis of individual pathophysiological composition opens new directions towards personalised treatment of OSA, focusing not only on pharyngeal dilation, but also on technical or pharmaceutical interventions on muscle function or breathing regulationhttps://bit.ly/3sayhkd

Comparison of the Accuracy and Clinical Parameters of Patient-Specific and Conventionally Bended Plates for Mandibular Reconstruction

Objectives

This retrospective study compared two mandibular reconstruction procedures-conventional reconstruction plates (CR) and patient-specific implants (PSI)-and evaluated their accuracy of reconstruction and clinical outcome.

Methods

Overall, 94 patients had undergone mandibular reconstruction with CR (n = 48) and PSI (n = 46). Six detectable and replicable anatomical reference points, identified via computer tomography, were used for defining the mandibular dimensions. The accuracy of reconstruction was assessed using pre- and postoperative differences.

Results

In the CR group, the largest difference was at the lateral point of the condyle mandibulae (D2) -1.56 mm (SD = 3.8). In the PSI group, the largest difference between preoperative and postoperative measurement was shown at the processus coronoid (D5) with +1.86 mm (SD = 6.0). Significant differences within the groups in pre- and postoperative measurements were identified at the gonion (D6) [t(56) = -2.217; p = .031 <.05]. In the CR group, the difference was 1.5 (SD = 3.9) and in the PSI group -1.04 (SD = 4.9). CR did not demonstrate a higher risk of plate fractures and post-operative complications compared to PSI.

Conclusion

For reconstructing mandibular defects, CR and PSI are eligible. In each case, the advantages and disadvantages of these approaches must be assessed. The functional and esthetic outcome of mandibular reconstruction significantly improves with the experience of the surgeon in conducting microvascular grafts and familiarity with computer-assisted surgery. Interoperator variability can be reduced, and training of younger surgeons involved in planning can be reaching better outcomes in the future.

Mandible reconstruction with free fibula flaps: Accuracy of a cost-effective modified semicomputer-assisted surgery compared with computer-assisted surgery - A retrospective study

A new individualized, cost-effective, modified semi-computer-assisted surgery (MSCAS) concept for free fibular flap mandibular reconstruction is reported and compared with the computer-assisted surgery (CAS) concept. Patients were divided into two groups and retrospectively reviewed. In the MSCAS and CAS groups, intraoperative guides were created using computer-aided design with manual fabrication and computer-aided design and manufacturing, respectively. Differences in specific linear and angular parameters on pre- and postoperative computed tomography scans were calculated for morphometric comparison, and clinical parameters and efficiency were analysed. RESULTS: Eighteen patients (CAS, 7; MSCAS, 11), were included. The morphometric comparison showed no significant differences between the groups. The mean deviation of the mandibular ramus length, body length, width 1 and width 2 was 0.82 ± 0.29 mm, 1.84 ± 0.43 mm, 1.89 ± 0.61 mm and 1.45 ± 0.61 mm in the CAS group versus 1.56 ± 0.54 mm, 1.72 ± 0.33 mm, 2.24 ± 0.55 mm and 2.36 ± 0.50 mm in the MSCAS group (p = 0.7804, p = 0.9997, p = 0.9814 and p = 0.6334). The mean deviation of the sagittal, axial and coronal mandibular angles was 1.56 ± 0.48°, 1.93 ± 0.50° and 2.15 ± 0.72° in the CAS group versus 2.19 ± 0.35°, 1.86 ± 0.35° and 1.94 ± 0.55° in the MSCAS group (p = 0.7594, p = 0.9996 and p = 0.9871). There were no significant differences in clinical parameters, efficiency or postoperative complications between the groups. CONCLUSION: The accuracy and operative efficiency of the MSCAS concept are comparable to those of the more expensive CAS concept. Therefore, in times of increasing clinical costs, this concept might be an adequate and inexpensive alternative to preoperative CAS.

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.

A comparison of postoperative, three-dimensional soft tissue changes in patients with skeletal class III malocclusions treated via orthodontics-first and surgery-first approaches

The aim of this retrospective study was to compare three-dimensional (3D) soft tissue and hard tissue changes between orthodontics-first approach (OFA) and surgery-first approach (SFA) after mandibular setback surgery. All patients underwent bilateral sagittal split osteotomy, and were examined by lateral cephalograms and 3D optical scanner before surgery (T0) and 1 (T1), 3 (T2), and 12 (T3) months after surgery. Three standard angles (FMA, U1 to FH, IMPA) were measured as hard tissue change and the 2 sets of 3D data were superimposed, and volumetric differences were calculated as soft tissue change. Statistical analyses were performed by using unpaired t-tests. Differences with P < 0.05 were considered significant. A total of 39 patients with mandibular prognathism were included in this study. The OFA group consisted of 24 patients and the SFA group of 15 patients. The SFA group exhibited more labial inclination from T1 to T2 (p = 0.008) and T2 to T3 (p = 0.003) than did the OFA group. There were no significant changes at maxilla and mandible at each term of T0, T1, T2 and T3 (p > 0.05), but compared to before surgery, mandibular volume in SFA group significant increased at 1year (p = 0.049) after surgery. We found that the soft tissue changes after the SFA differed significantly from those after the OFA; thus, soft tissue predictions require more care. An analysis of our data compared with OFA and SFA for the patient with mandibular prognathism confirm that the mandibular soft tissue changes by postoperative orthodontic treatment and occlusal relationship in SFA.

Computer-assisted versus traditional freehand technique for mandibular reconstruction with free vascularized fibular flap: A matched-pair study

OBJECTIVES

This study aimed to perform a surgery-related and patient-related outcome analysis of a case-matched series of patients treated with computer-assisted surgery (CAS) and traditional freehand surgery.

METHODS

A total of 153 patients who underwent mandibular reconstruction by VFF were included from Jan 1999 to Dec 2019. The mandibular resection and reconstruction were performed by four experienced oral and maxillofacial surgeons. Reasons for reconstruction were oncologic, osteoradionecrosis, trauma, and osteoporosis. All the patients were followed up postoperatively for at least 1 year. Eighteen pairs were formed with the matched cohort consisting of a total of 36 patients who underwent primary mandibular reconstruction without additional combined flaps. The surgery-related and patient-related continuous and categorical parameters were assessed in both groups.

RESULTS

The average operation time and bleeding volume in the CAS group were less than those in the non-CAS group. Additionally, both hospitalization and ICU days were lower in the CAS group without any significant difference. The only significant finding related to surgical parameters was observed for the ischemia time, which was lower in the CAS group.

CONCLUSIONS

Computer-assisted surgery indicated improved efficiency considering reduced ischemia time, operation time, and length of hospital stay with lower early complications than that of conventional surgical procedures. It can thus be considered as an optimized alternative to the freehand approach.

Virtual planning and CAD/CAM-assisted distraction for maxillary hypoplasia in cleft lip and palate patients: Accuracy evaluation and clinical outcome

The aim of this prospective study was to report the experience with a specific guided distraction protocol for the treatment of CLP patients with severe midface hypoplasia. From January 2016 to April 2019, six consecutive, non-growing, CLP patients with maxillary hypoplasia underwent a specific distraction protocol based on the use of VSP, CAD/CAM-generated surgical splints, cutting guides, prebent internal maxillary distractors, early removal of distractors, and acute callus manipulation and fixation. STL files for VSP, using multislice CT scans taken preoperatively (T0) and 3 months after distractor removal (T1) were superimposed using the free software 3D Slicer and Geomagic Wrap to evaluate the accuracy of maxillary repositioning and assess 3D bone changes. Clinical outcome was evaluated at the 1-year follow-up (T2). The patients and surgeon were satisfied with the occlusal and aesthetic outcomes. A maximum difference of 2 mm between the VSP and the actual surgical outcome was chosen as the success criterion for accuracy. The average linear difference for selected points was <2 mm in four patients and >2 mm in two patients. The average distance of the postoperative maxilla from the VSP model was 2.28 mm (median 1.85), while the average forward movement of the maxilla was 10.18 mm The protocol used is effective and accurate in the correction of severe maxillary hypoplasia in CLP patients. Early removal of the distractor and stabilization with plates reduces patient discomfort and does not jeopardize stability. This protocol should be reserved for complex cases due to the costs of the procedure, which are not negligible.

Accuracy of guided biopsy of the jawbone in a clinical setting: A retrospective analysis

The aim of this study was to investigate the accuracy of a previously described technique for guided biopsy of osseous pathologies of the jawbone in a clinical setting. The data sets of patients who had undergone guided biopsy procedures were retrospectively examined for accuracy. Digital planning of the biopsies and manufacturing of the tooth-supported drilling template were performed with superimposed cone beam computed tomography and intraoral scans using implant planning software. After a trephine biopsy was taken using the template, the postoperative low-dose cone beam computed tomography was analyzed for accuracy using the planning software with the corresponding (digitally-planned) biopsy cylinder. The mean angular deviation was 4.35 ± 2.5°. The mean depth deviation was -1.40 ± 1.41 mm. Guided biopsy seems to be an alternative to a conventional approach for minimally invasive and highly accurate jawbone biopsy.

A Novel Treatment Concept for Advanced Stage Mandibular Osteoradionecrosis Combining Isodose Curve Visualization and Nerve Preservation: A Prospective Pilot Study

Background

Osteoradionecrosis (ORN) of the mandible is a severe complication of radiation therapy in head and neck cancer patients. Treatment of advanced stage mandibular osteoradionecrosis may consist of segmental resection and osseous reconstruction, often sacrificing the inferior alveolar nerve (IAN). New computer-assisted surgery (CAS) techniques can be used for guided IAN preservation and 3D radiotherapy isodose curve visualization for patient specific mandibular resection margins. This study introduces a novel treatment concept combining these CAS techniques for treatment of advanced stage ORN.

Methods

Our advanced stage ORN treatment concept includes consecutively: 1) determination of the mandibular resection margins using a 3D 50 Gy isodose curve visualization, 2) segmental mandibular resection with preservation of the IAN with a two-step cutting guide, and 3) 3D planned mandibular reconstruction using a hand-bent patient specific reconstruction plate. Postoperative accuracy of the mandibular reconstruction was evaluated using a guideline. Objective and subjective IAN sensory function was tested for a period of 12 months postoperatively.

Results

Five patients with advanced stage ORN were treated with our ORN treatment concept using the fibula free flap. A total of seven IANs were salvaged in two men and three women. No complications occurred and all reconstructions healed properly. Neither non-union nor recurrence of ORN was observed. Sensory function of all IANs recovered after resection up to 100 percent, including the patients with a pathologic fracture due to ORN. The accuracy evaluation showed angle deviations limited to 3.78 degrees. Two deviations of 6.42° and 7.47° were found. After an average of 11,6 months all patients received dental implants to complete oral rehabilitation.

Conclusions

Our novel ORN treatment concept shows promising results for implementation of 3D radiotherapy isodose curve visualization and IAN preservation. Sensory function of all IANs recovered after segmental mandibular resection.

Maxillofacial reconstruction with prefabricated prelaminated osseous free flaps

BACKGROUND

The prefabricated fibula flap is an advanced method of occlusal-based reconstruction that combines placement of osseointegrated dental implants with prelamination, using a split skin graft on the fibula, weeks prior to the definitive reconstruction. This approach is resource intensive but has several advantages including eliminating the delay from reconstruction to dental rehabilitation.

METHODS

A retrospective cohort study of all prefabricated fibula flaps used for mandible and maxillary reconstruction from 2012 to 2020 was performed. Outcome measures were implant survival, implant utilization and functional dental rehabilitation.

RESULTS

A total of 17 prefabricated fibula flaps were performed including two analogue and 15 digital plans. There were nine maxillary and eight mandibular reconstructions, of which 11 were primary and seven were secondary. There were no free flap failures. A total of 65 implants were placed (average 3.8, median 3 implants). There was one implant failure at 6 years giving a 1.5% failure rate. There was 91% implant utilization and 94% functional dental rehabilitation.

CONCLUSION

The prefabricated fibula flap provides outstanding dental rehabilitation in well-selected patients.

Recent advances in orthognathic surgery

PURPOSE OF REVIEW

The aim of this article is to review the recent literature on orthognathic surgery for treatment of malocclusion and obstructive sleep apnea (OSA). The discussion outlines the refinements of the procedure and advances in technology.

RECENT FINDINGS

Maxillomandibular advancement (MMA) may be performed for complex malocclusion and OSA. Although orthodontic management followed by MMA has been the gold standard in managing complex cases, the surgery first approach for treatment of malocclusion has increased in popularity because of decreased treatment time and improved patient quality of life. MMA continues to be the gold-standard for treatment of refractory sleep apnea. Technological advancements, including 3D printing and virtual surgical planning, have enhanced the patient experience and provided more efficiency to this surgery.

SUMMARY

First introduced in the 19th century, orthognathic surgery has continuously been refined. Over the last few decades, there has been increasing support for a surgery first approach in the treatment of malocclusion. MMA has revolutionized the surgical treatment of OSA and provides the best opportunity for success or cure in patients with complex obstructive patterns. Technology has enhanced the surgical process and created more efficiency for the surgeon and patient. VIDEO ABSTRACT: http://links.lww.com/COOH/A40.