Neonatal mandibular distraction osteogenesis: converting virtual surgical planning into an operative reality

Computerized Surgical Planning for Mandibular Distraction Osteogenesis

Mandibular distraction osteogenesis is a technically challenging procedure due to complex mandibular anatomy, especially in the treatment of Pierre-Robin Sequence due to variable bone thickness in the infant mandible and the presence of tooth buds. Computerized surgical planning (CSP) simplifies the procedure by preoperatively visualizing critical structures, producing cutting guides, and planning distractor placement. This paper describes the process of using CSP to plan mandibular distraction osteogenesis, including discussion of recent advances in the use of custom distractors.

3D Printing Applications for Craniomaxillofacial Reconstruction: A Sweeping Review

The field of craniomaxillofacial (CMF) surgery is rich in pathological diversity and broad in the ages that it treats. Moreover, the CMF skeleton is a complex confluence of sensory organs and hard and soft tissue with load-bearing demands that can change within millimeters. Computer-aided design (CAD) and additive manufacturing (AM) create extraordinary opportunities to repair the infinite array of craniomaxillofacial defects that exist because of the aforementioned circumstances. 3D printed scaffolds have the potential to serve as a comparable if not superior alternative to the "gold standard" autologous graft. In vitro and in vivo studies continue to investigate the optimal 3D printed scaffold design and composition to foster bone regeneration that is suited to the unique biological and mechanical environment of each CMF defect. Furthermore, 3D printed fixation devices serve as a patient-specific alternative to those that are available off-the-shelf with an opportunity to reduce operative time and optimize fit. Similar benefits have been found to apply to 3D printed anatomical models and surgical guides for preoperative or intraoperative use. Creation and implementation of these devices requires extensive preclinical and clinical research, novel manufacturing capabilities, and strict regulatory oversight. Researchers, manufacturers, CMF surgeons, and the United States Food and Drug Administration (FDA) are working in tandem to further the development of such technology within their respective domains, all with a mutual goal to deliver safe, effective, cost-efficient, and patient-specific CMF care. This manuscript reviews FDA regulatory status, 3D printing techniques, biomaterials, and sterilization procedures suitable for 3D printed devices of the craniomaxillofacial skeleton. It also seeks to discuss recent clinical applications, economic feasibility, and future directions of this novel technology. By reviewing the current state of 3D printing in CMF surgery, we hope to gain a better understanding of its impact and in turn identify opportunities to further the development of patient-specific surgical care.

Preliminary study of the accuracy and safety of robot-assisted mandibular distraction osteogenesis with electromagnetic navigation in hemifacial microsomia using rabbit models

This study aimed to investigate the accuracy and safety of mandibular osteotomy and distraction device positioning in distraction osteogenesis assisted by an electromagnetic navigation surgical robot. Twelve New Zealand white rabbits were randomly divided into two groups after computed tomography. The control group underwent a procedure based on the preoperative three-dimensional design and clinical experience. Animals in experimental group underwent a procedure with robotic assistance after registration. The accuracies of osteotomy and distraction device positioning were analysed based on distance and angular errors. The change in ramus length after a 1 cm-extension of the distraction device was for assessing distraction effect. The preparation, operative and osteotomy times, intraoperative bleeding, and teeth injury were used for safety assessment. In the experimental group, the distance (t = 2.591, p = 0.011) and angular (t = 4.276, p = 0.002) errors of osteotomy plane, and the errors in distraction device position (t = 3.222, p = 0.009) and direction (t = 4.697, p = 0.001) were lower; the distraction effect was better (t = 4.096, p = 0.002). There was no significant difference in the osteotomy time and bleeding; however, the overall operative and preparation times were increased in the experimental group, with a reduced rate of teeth damage. Robot-assisted mandibular distraction osteogenesis with electromagnetic navigation in craniofacial microsomia is feasible, safe, significantly improves surgical precision.

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.

Intraoperative Navigation in Plastic Surgery with Augmented Reality: A Preclinical Validation Study

BACKGROUND

Augmented reality allows users to visualize and interact with digital images including three-dimensional holograms in the real world. This technology may have value intraoperatively by improving surgical decision-making and precision but relies on the ability to accurately align a hologram to a patient. This study aims to quantify the accuracy with which a hologram of soft tissue can be aligned to a patient and used to guide intervention.

METHODS

A mannequin's face was marked in a standardized fashion with 14 incision patterns in red and nine reference points in blue. A three-dimensional photograph was then taken, converted into a hologram, and uploaded to HoloLens (Verto Studio LLC, San Diego, Calif.), a wearable augmented reality device. The red markings were then erased, leaving only the blue points. The hologram was then viewed through the HoloLens in augmented reality and aligned onto the mannequin. The user then traced the overlaid red markings present on the hologram. Three-dimensional photographs of the newly marked mannequin were then taken and compared with the baseline three-dimensional photographs of the mannequin for accuracy of the red markings. This process was repeated for 15 trials (n = 15).

RESULTS

The accuracy of the augmented reality-guided intervention, when considering all trials, was 1.35 ± 0.24 mm. Markings that were positioned laterally on the face were significantly more difficult to reproduce than those centered around the facial midline.

CONCLUSIONS

Holographic markings can be accurately translated onto a mannequin with an average error of less than 1.4 mm. These data support the notion that augmented reality navigation may be practical and reliable for clinical integration in plastic surgery.

Evaluating Sensory Nerve Outcomes After Horizontal Osteotomy for Mandibular Distraction in Infant Robin Sequence Patients

ABSTRACT

There has yet to be a consensus on the appropriate technique for mandibular distraction in the infant Pierre Robin population nor is their sufficient data on sensory nerve outcomes. The purpose of this study is to validate the safety of the horizontal osteotomy by: (1) determining mandibular foramen location in infant Pierre Robin patients relative to the dentoalveolar plane and (2) evaluate long-term function of the inferior alveolar nerve in previously distracted Pierre Robin patients. Preoperative 3D Computed tomography (CT) scans of Pierre Robin patients < 1 year old were reviewed. A line at the level of the mandibular dentoalveolar plane was drawn across the lingual surface of the ramus and the distance to the mandibular foramen was then measured. Semmes-Weinstein monofilaments of the lower lip and chin bilaterally was performed on mandibular distraction patients in clinic. Inclusion criteria was patients >6 years of age having undergone bilateral mandibular distraction at <1 year of age. Fifteen patients' CT studies were examined. The mandibular foramen was consistently below the level of the dentoalveolar plane at an average distance of 4.7 mm. Eight patients were included in the prospective arm. Average age was 12.2. All patients had normal sensation at 2.83 through all areas. The mandibular foramen reliably exists below the dentoalveolar plane. In addition, all patients reviewed postoperatively with >10 years of follow up demonstrated normative sensation. The horizontal corticotomy performed just above the mandibular dentoalveolar plane spares the inferior alveolar nerve in young Pierre Robin patients undergoing distraction.

The development of computer-aided patient-specific template design software for 3D printing in cranio-maxillofacial surgery

BACKGROUND

The patient-specific templates for osteotomy often have complex surface features. Using current commercial software to design such templates is quite complicated, tedious and unrepeatable.

AIMS

In this study, a novel surgical planning system for oral and maxillofacial surgery named EasyTemplate is developed, aiming to help doctors shorten the modelling time and assure the reliability in template design.

MATERIALS & METHODS

In the simplified design process of an osteotomy guide, the main template can be formed efficiently using a surface offsetting algorithm, which is based on isosurface extraction and oriented bounding box. Thereafter, the cutting grooves can be generated automatically.

RESULTS

A complicated surgical guide could be built accurately in about 10 min. Clinical orthognathic cases were conducted successfully using osteotomy and repositioning templates designed by EasyTemplate.

DISCUSSION

Compared with commercially available softwares, higher efficiency and simpler design process were achieved, moreover, the time cost is one-third or even less.

CONCLUSION

EasyTemplate can be a useful alternative to traditional softwares. This software allows the auto-generation algorithm which helps avoid a tedious modeling process while providing basic shapes for designers.

Virtual Surgical Planning and the “In-House” Rapid Prototyping Technique in Maxillofacial Surgery: The Current Situation and Future Perspectives

Background: The first applications of computer-aided design/computer-aided manufacturing (CAD/CAM) in maxillofacial surgery date back to the 1980s. Since then, virtual surgical planning (VSP) has undergone significant development and is now routinely used in daily practice. Indeed, in an extraordinary period, such as that of the current COVID-19 pandemic, it offers a valuable tool in relation to the protection of healthcare workers. In this paper we provide a comprehensive summary of the clinical applications reported in the literature and review our experience using an in-house rapid prototyping technique in the field of maxillofacial surgery. methods: Our research was focused on reconstructive surgery, traumatology (especially in relation to orbital floor and zygomatic arch fractures), and COVID-19 masks. The first step was a radiographic study. Next, computed tomography (CT) scans were segmented in order to obtain a three-dimensional (3D) model. Finally, in the editing phase, through the use of specific software, a customized device for each patient was designed and printed. results: Four reconstructive procedures were performed with a perfect fitting of the surgical device produced by means of VSP. In nine orbital floor fracture cases a good overlapping of the mesh on the orbital floor was obtained. In sixteen zygomatic arch cases the post-operative CT scan showed an excellent fitting of the device and a correct fracture reduction. Regarding the COVID-19 period, six masks and shields produced proved to provide effective protection. conclusions: The timescale and costs required for the production of our “home-made” virtual design are low, which makes this method applicable to a large number of cases, for both ordinary and extraordinary activities.

Risk Factors of Prolonged Mechanical Ventilation in Infants With Pierre Robin Sequence After Mandibular Distraction Osteogenesis: A Retrospective Cohort Study

Background: After mandibular distraction osteogenesis (MDO), most infants with Pierre Robin sequence (PRS) require mechanical ventilation to assist their breathing. However, the optimal duration of intubation during early mandibular distraction osteogenesis activation is poorly understood. This retrospective study was carried out to identify perioperative risk factors of prolonged mechanical ventilation in infants undergoing MDO. Methods: A total of 95 infants with PRS underwent MDO at Guangzhou Women and Children's Medical Center between 2016 and 2018, and the clinical records of 74 infants who met the selection criteria were analyzed. Of the 74 infants, 26 (35.1%) underwent prolonged mechanical ventilation, 48 (64.9%) did not. t-test, Wilcoxon Sum Rank test or chi-squared test were performed to compare variables that might associate with prolonged mechanical ventilation between the two groups, and then, significant variables identified were included in the multivariate logistic regression model to identify independent variables. Results: Univariate logistic regression analysis revealed that age, preoperative gonial angle, and postoperative pulmonary infection were associated with prolonged mechanical ventilation (all P < 0.05). Multivariate logistic regression analysis confirmed that the preoperative gonial angle and postoperative pulmonary infection were independent risk factors of prolonged mechanical ventilation (both P < 0.05). Conclusions: Infants with PRS and smaller preoperative gonial angle or postoperative pulmonary infection may be more likely to undergo prolonged mechanical ventilation after MDO. For others, extubation may be attempted within 6 days after MDO.

Accuracy of virtually planned mandibular distraction in a pediatric case series

The aim of this study was to describe the utility of 3D technology in mandibular distraction (MD) for patients with mandibular hypoplasia (MH), using 3D-printed cutting guides (CGs), and to assess the differences between virtual surgical planning (VSP) and the final result. A descriptive retrospective study of five patients diagnosed with MH, who required unilateral or bilateral MD, was carried out between January 2018 and January 2020. All patients underwent preoperative craniofacial CT scan and a 3D VSP was executed. MD was performed with the help of the 3D-printed CG. Before removal of the distractor, another CT scan was performed to compare the actual final result with the VSP. A mean difference of <4° was found for the osteotomy direction, < 7° for distractor position, and <2 mm for posterior screw placement. VSP and 3D-printed CGs have revolutionized surgical planning, facilitating surgical treatment and improving the final result. In our sample, the variations in osteotomy line, distractor position, and posterior screw placement have been minor, making the outcome more predictable.

Optimal duration of mechanical ventilation and influencing factors following mandibular distraction osteogenesis in infants with Pierre Robin sequence

Mandibular distraction osteogenesis (MDO) is an effective treatment for tongue-based airway obstruction in infants with severe Pierre Robin sequence (PRS). Most infants receiving MDO require postoperative mechanical ventilation (MV) to assist breathing. Optimal MV time for each individual patient and factors influencing the time must be identified to guide clinical decision-making.A retrospective analysis was performed on 75 infants with PRS receiving MDO from November 2016 to August 2018. Twenty-six were females and 47 were males. Data extracted from the hospital information system included sex, age, weight, history of preterm labor, preoperative pulmonary infection, laryngomalacia/tracheomalacia, laryngoscope exposure classification, anesthesia duration, operation duration, postoperative treatment site, situation of distraction, postoperative complications and MV duration. Statistical analyses were conducted to investigate the potential associations of these factors with MV time.Seventy-three PRS syndrome patients received anesthesia for MDO device procedures were considered eligible for study. Patient sex, history of preterm labor, preoperative pulmonary infection, laryngomalacia/tracheomalacia, laryngoscopy exposure difficulty, postoperative treatment site (neonatal or pediatric intensive care unit), ventilator-associated pneumonia, age, weight, anesthesia duration, and operation duration had no significant influence on postsurgical MV time (P > .05). Amount of distraction at the time of extubation had statistically significant influence on postoperative MV time (P < .05). In addition, scatter plots revealed linear relationships between postoperative MV time and amount of distraction at extubation.According to this analysis, amount of distraction was associated with MV time following MDO for severe PRS and roughly 6 days post-surgery is a generally safe extubation time.

The New Frontier: A Review of Augmented Reality and Virtual Reality in Plastic Surgery

Mixed reality, a blending of the physical and digital worlds, can enhance the surgical experience, leading to greater precision, efficiency, and improved outcomes. Various studies across different disciplines have reported encouraging results using mixed reality technologies, such as augmented and virtual reality. To provide a better understanding of the applications and limitations of this technology in plastic surgery, we performed a systematic review of the literature in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The initial query of the National Center for Biotechnology Information database yielded 2544 results, and only 46 articles met our inclusion criteria. The majority of studies were in the field of craniofacial surgery, and uses of mixed reality included preoperative planning, intraoperative guides, and education of surgical trainees. A deeper understanding of mixed reality technologies may promote its integration and also help inspire new and creative applications in healthcare.

Mathematical Modeling and Virtual Reality Simulation of Surgical Tool Interactions With Soft Tissue: A Review and Prospective

This is an informed assessment of the state of the art and an extensive inventory of modeling approaches and methods for soft tissue/medical cutting tool interaction and of the associated medical processes and phenomena. Modeling and simulation through numerical, theoretical, computational, experimental, and other methods was discussed in comprehensive review sections each of which is concluded with a plausible prospective discussion biased toward the development of so-called virtual reality (VR) simulator environments. The finalized prospective section reflects on the future demands in the area of soft tissue cutting modeling and simulation mostly from a conceptual angle with emphasis on VR development requirements including real-time VR simulator response, cost-effective “close-to-reality” VR implementations, and other demands. The review sections that serve as the basis for the suggested prospective needs are categorized based on: (1) Major VR simulator applications including virtual surgery education, training, operation planning, intraoperative simulation, image-guided surgery, etc. and VR simulator types, e.g., generic, patient-specific and surgery-specific and (2) Available numerical, theoretical, and computational methods in terms of robustness, time effectiveness, computational cost, error control, and accuracy of modeling of certain types of virtual surgical interventions and their experimental validation, geared toward ethically driven artificial “phantom” tissue-based approaches. Digital data processing methods used in modeling of various feedback modalities in VR environments are also discussed.

Virtual Surgical Planning: The Pearls and Pitfalls

Objective

Over the past few years, virtual surgical planning (VSP) has evolved into a useful tool for the craniofacial surgeon. Virtual planning and computer-aided design and manufacturing (CAD/CAM) may assist in orthognathic, cranio-orbital, traumatic, and microsurgery of the craniofacial skeleton. Despite its increasing popularity, little emphasis has been placed on the learning curve.

Methods

A retrospective analysis of consecutive virtual surgeries was done from July 2012 to October 2016 at the University of Montreal Teaching Hospitals. Orthognathic surgeries and free vascularized bone flap surgeries were included in the analysis.

Results

Fifty-four virtual surgeries were done in the time period analyzed. Forty-six orthognathic surgeries and 8 free bone transfers were done. An analysis of errors was done. Eighty-five percentage of the orthognathic virtual plans were adhered to completely, 4% of the plans were abandoned, and 11% were partially adhered to. Seventy-five percentage of the virtual surgeries for free tissue transfers were adhered to, whereas 25% were partially adhered to. The reasons for abandoning the plans were (1) poor communication between surgeon and engineer, (2) poor appreciation for condyle placement on preoperative scans, (3) soft-tissue impedance to bony movement, (4) rapid tumor progression, (5) poor preoperative assessment of anatomy.

Conclusion

Virtual surgical planning is a useful tool for craniofacial surgery but has inherent issues that the surgeon must be aware of. With time and experience, these surgical plans can be used as powerful adjuvants to good clinical judgement.

Application of a newly designed mandibular distraction device for navigation surgery in goats

PURPOSE

This animal study is to investigate the accuracy of navigation-guided mandibular distraction osteogenesis with a special designed distraction device by TBNavis-CMFS navigation system.

MATERIALS AND METHODS

Four goats were included in this study. The 3D simulation unilateral mandibular distraction osteogenesis was simulated for 14 mm lengthening in TBNavis-CMFS navigation system. A new designed mandibular distraction device with the detachable adapter for navigation surgery in combination with the specific mandibular dynamic reference frame was applied. Navigation guided distraction osteogenesis was performed on goats and mandible was gradually distracted according to the simulation. Postsurgical 3-D skeletal measurements of presurgical simulations and postsurgical outcomes were compared statistically.

RESULTS

Navigation assisted distraction osteogenesis was successfully performed and the new designed distraction devices worked uneventful. The accuracy of intra-operative registration was within 1 mm. The mandible was lengthened for 14.25 mm in average (13.87-14.36 mm). There were no significant differences between simulation distraction and post-operative 3-D measurements (p > 0.05).

CONCLUSIONS

A new designed distraction device could be used in navigation guided mandibular distraction osteogenesis on goats with high accuracy by using the TBNavis-CMFS navigation system.

Virtual Surgical Planning for Mandibular Distraction in Infants with Robin Sequence

Mandibular distraction osteogenesis (MDO) successfully relieves obstructive sleep apnea in many infants with Robin sequence. Preoperative virtual surgical planning and fabrication of three-dimensionally printed cutting guides may lead to further improvements in the MDO technique and decrease the risk for damage to adjacent structures such as developing teeth and the inferior alveolar nerve. This report presents an algorithm for virtual surgical planning and three-dimensionally printing of cutting guides for MDO in infants with RS.

Update on mandibular distraction osteogenesis

PURPOSE OF REVIEW

Mandibular distraction osteogenesis has become one of the most powerful reconstructive tools for addressing congenital lower jaw deformities. This review will focus on clinical and basic science contributions to the literature in the last year, which have shown innovations in mandibular distraction osteogenesis techniques and advances in outcomes.

RECENT FINDINGS

The longest phase of distraction is consolidation, when newly formed bone must fully heal. If consolidation could be accelerated, the length of time required for fixation would be less and complications associated with fixation devices would decline. In the last year, animal studies were conducted reporting the application of growth factors directly to distraction gaps to accelerate bone formation. Additional research in animal models showed success with the addition of bone marrow-derived mesenchymal stem cells to the distraction gap. Distraction devices are being piloted with automated, continuous formats compared with current devices that require manual activation. The use of surgical planning software programs to determine the location of osteotomies was another focus of current studies.

SUMMARY

Rates of activation can be accelerated with the addition of stem cells and growth factors to distraction sites, as could time to full consolidation. The addition of mesenchymal stem cells and deferoxamine and the use of low-intensity ultrasound during distraction are three of the most promising approaches reported in recent studies with potential for future translation from animal models. Computer-assisted presurgical planning offers added accuracy and potential time savings. Newer distraction devices using computer automation are still in preliminary phases, but show promise.

Virtual surgical planning in craniofacial surgery

The complex three-dimensional anatomy of the craniofacial skeleton creates a formidable challenge for surgical reconstruction. Advances in computer-aided design and computer-aided manufacturing technology have created increasing applications for virtual surgical planning in craniofacial surgery, such as preoperative planning, fabrication of cutting guides, and stereolithographic models and fabrication of custom implants. In this review, the authors describe current and evolving uses of virtual surgical planning in craniofacial surgery.