Three-Dimensional Printed Customized Surgical Guides for the Precise Correction of Complex Midfacial Post-Traumatic Deformities.

PURPOSE: The introduction of intraoperative computed tomography and image-guided navigation have demonstrated some advantages for the correction of midfacial post-traumatic deformities. However, these methods still do not achieve satisfactory results. The authors sought to describe a novel method for the precise correction of complex midfacial post-traumatic deformities using three-dimensional printing customized surgical guides. METHODS: Ten patients with midfacial post-traumatic deformities admitted between January 15, 2018 and August 20, 2020 were included. To design the surgical guide for each patient, preoperative planning and simulation datasets were used as a virtual template. Each surgical guide comprised three-dimensional printing cutting guides and customized titanium plates to guide the osteotomy and repositioning of the fracture fragments intraoperatively. Reduction and fixation were confirmed by intraoperative navigation. Postoperative deviation chromatography analysis and clinical examination were conducted to evaluate the surgical outcome. All operations were successfully performed. RESULTS: The average difference between the virtual plans and postoperative results was less than 1.5 mm. The 3- to 6-month follow-up evaluation demonstrated that symptoms were alleviated, and postoperative function and esthetics improved considerably. CONCLUSIONS: Three-dimensional-printed customized surgical guides can accurately and effectively transfer the virtual surgical plan to the patient and could be considered an ideal and valuable option for this potentially complicated procedure.

Introduction of Digital-Assisted Multidisciplinary Treatment in the Functional and Morphological Reconstruction of Naso-Orbital-Ethmoid Fractures.

ABSTRACT: This study summarizes the process of digital-assisted multidisciplinary treatment (MDT) of naso-orbital-ethmoid (NOE) fractures and evaluates the treatment outcomes. From October 2018 to December 2020, 39 patients with NOE fractures were treated in our department, 21 of whom were diagnosed and treated by a multidisciplinary team. After preoperative multidisciplinary discussions and personalized virtual surgical planning, they received MDT with the assistance of a surgical navigation system. The other 18 patients received traditional single-disciplinary treatment, that is, no preoperative multidisciplinary discussions. Oral and maxil-lofacial surgeons performed surgical design and digitally-assisted surgery alone. After the operation, treatment outcomes were evaluated in terms of aesthetic appearance and function. The duration of preoperative preparation and postoperative aesthetic outcomes were not significantly different in patients who received single-disciplinary treatment and MDT ( P > 0.05). However, postoperative functional outcomes were significantly better in patients who received MDT ( P < 0.05). Furthermore, no significant complications were found. Digital-assisted MDT has a high application value in repair and appearance reconstruction, especially restoring functionality after NOE fracture; thus, it should be promoted in clinical practice.

Collaborative Control Method and Experimental Research on Robot-Assisted Craniomaxillofacial Osteotomy Based on the Force Feedback and Optical Navigation.

OBJECTIVE: Surgical robot has advantages in high accuracy and stability. But during the robot-assisted bone surgery, the lack of force information from surgical area and incapability of intervention from surgeons become the obstacle. The aim of the study is to introduce a collaborative control method based on the force feedback and optical navigation, which may optimally combine the excellent performance of surgical robot with clinical experiences of surgeons. MATERIALS AND METHODS: The CMF ROBOT system was integrated with the force feedback system to ensure the collaborative control. Force-velocity control algorithm based on force feedback was designed for this control method. In the preliminary experimental test, under the collaborative control mode based on force feedback and optical navigation, the craniomaxillofacial surgical robot entered the osteotomy line area according to the preoperative surgical plan, namely, right maxillary Le Fort I osteotomy, left maxillary Le Fort I osteotomy, and genioplasty. RESULTS: The force sensor was able to collect and record the resistance data of the cutting process of the robot-assisted craniomaxillofacial osteotomy assisted in real time. The statistical results showed that the repeatability of collaborative control mode was acceptable in bilateral maxillary Le Fort I osteotomies (right, P =0.124>0.05 and left, P =0.183>0.05) and unfavorable in genioplasty ( P =0.048<0.05). CONCLUSION: The feasibility of robot-assisted craniomaxillofacial osteotomy under the collaborative control method based on the force feedback and optical navigation was proved in some extent. The outcome of this research may improve the flexibility and safety of surgical robot to meet the demand of craniomaxillofacial osteotomy.

Classifying and standardizing panfacial trauma according to anatomic categories and Facial Injury Severity Scale: a 10-year retrospective study.

BACKGROUND: The purpose of this study was to identify the epidemiologic factors of panfacial fractures (PFs), and to evaluate the significance of anatomic PF categories and the Facial Injury Severity Scale (FISS) in classifying and standardizing panfacial injuries. METHODS: A retrospective review of all patients treated with PFs at our institution between June 2010 and April 2021 was performed. PF was defined as a concurrent fracture in at least 3 of 4 facial subunits (frontal, upper midface, lower midface, and mandible). Data regarding patient demographics, causes of injury, location of fractures, major concomitant injuries, and postinjury complications were collected, and the FISS score was collected from each patient. Statistical analysis was performed using IBM SPSS Statistics version 22.0. RESULTS: A total of 227 patients were enrolled. The most commonly fractured bones were the maxillary sinus wall (92.1%), mandible (82.8%), and zygomatic arch (75.3%), and the most common fracture sites in PFs were graphically presented. Four PF patterns were defined: FULM (n = 60), FUL (n = 39), ULM (n = 127), and FUM (n = 1). There was a significant association between PF patterns and sex (p = 0.018), the number of concomitant injuries (p = 0.014), and early surgical airway management (p = 0.003). Different PF patterns were significantly correlated with different types of concomitant injuries and complications. The FISS score showed a significant difference with PF patterns (p = 0.000) and sex (p = 0.007), and a FISS value of 11 or more is the appropriate cutoff for the prediction of multiple concomitant injuries and complications. CONCLUSIONS: Both the anatomic PF categories and FISS were significantly correlated with various concomitant injuries and complications. The combination of PF categories and FISS provided a better positive and negative prediction of concomitant injuries and complications for PF patients. Patients with FULM and FISS > 11 had an obviously higher proportion of the need for multiprofessional treatment.

A Modified Method Using Double Computed Tomography Scan Procedure to Maintain Mandibular Width in Mandibular Reconstruction.

OBJECTIVE: The purpose of this study was to evaluate the use of a modified template system and double computed tomography scan procedure to maintain mandibular width in cases of mandibular reconstruction. STUDY DESIGN: Ten patients who underwent mandibular reconstruction with a fibular flap were enrolled. The surgeries were planned with a computer-aided surgical simulation (CASS) planning method. Following double computed tomography scan procedure, the template system was designed in a computer and was fabricated using a three-dimensional printing technique. The cutting guides were designed with the holes of the conventional reconstruction plate on the remnant mandibular segments. After surgery, the outcome evaluation was compared by first superimposing the post-operative computed tomography model onto the planned model and then measuring the differences between the planned and actual outcomes. RESULTS: All surgeries were completed successfully using the template system. With the use of the templates, the largest linear root-mean-square deviation (RMSD) between the planned and post-operative remnant segments was 1.01 mm, and the largest angular RMSD was 4.05°. CONCLUSIONS: The authors conclude that this template system and double computed tomography scan procedure provides a reliable method to maintain mandibular width in mandibular reconstruction using a fibular flap.

New Solutions to Improve the Accuracy of the Navigation-Guided Foreign Body Removal in Craniomaxillofacial Deep Space.

OBJECTIVE: Surgical navigation-guided removal of foreign bodies in the craniomaxillofacial region has been proven to be an effective method. However, there have been some unsuccessful patients due to reduced navigation accuracy or complicated and undetectable anatomy. This article summarizes the experience and proposes some solutions to achieve better results. STUDY DESIGN: Two solutions were proposed to optimize the surgical navigation procedure: using a 3-dimensionally printed customized mandible retainer to indirectly maintain the consistency of the foreign body's visual images of preoperative planning and intraoperative navigation and importing real-time endoscopic imaging during surgery to provide vision under complex anatomy. Two patients were selected for each method. RESULTS: The foreign bodies were successfully and minimally invasively removed in all patients assisted by optimized surgical navigation. During follow-up at 3 to 6 months postoperatively, no complications were found. CONCLUSION: Improving navigation accuracy and providing real vision might be effective at compensating for insufficient navigation due to navigation positioning errors or the interference of imperceptible and complicated anatomy.

Error Analysis of Robot-Assisted Orthognathic Surgery.

OBJECTIVE: Orthognathic surgery is an effective method to correct the dentomaxillofacial deformities. The aim of the study is to introduce the robot-assisted orthognathic surgery and demonstrate the accuracy and feasibility of robot-assisted osteotomy in transferring the preoperative virtual surgical planning (VSP) into the intraoperative phase. METHODS: The CMF robot system, a craniomaxillofacial surgical robot system was developed, consisted of a robotic arm with 6 degrees of freedom, a self-developed end-effector, and an optical localizer. The individualized end-effector was installed with reciprocating saw so that it could perform osteotomy. The study included control and experimental groups. In control group, under the guidance of navigation system, surgeon performed the osteotomies on 3 skull models. In experimental group, according to the preoperative VSP, the robot completed the osteotomies on 3 skull models automatically with assistance of navigation. Statistical analysis was carried out to evaluate the accuracy and feasibility of robot-assisted orthognathic surgery and compare the errors between robot-assisted automatic osteotomy and navigation-assisted manual osteotomy. RESULTS: All the osteotomies were successfully completed. The overall osteotomy error was 1.07 ±â€Š0.19 mm in the control group, and 1.12 ±â€Š0.20 mm in the experimental group. No significant difference in osteotomy errors was found in the robot-assisted osteotomy groups (P = 0.353). There was consistence of errors between robot-assisted automatic osteotomy and navigation-assisted manual osteotomy. CONCLUSION: In robot-assisted orthognathic surgery, the robot can complete an osteotomy according to the preoperative VSP and transfer a preoperative VSP into the actual surgical operation with good accuracy and feasibility.

A New Modified Method for Accurate Mandibular Reconstruction.

Mandible plays a pivotal role for both function (mastication, swallowing, and phonation) and aesthetic. Traumas, osteomyelitis, osteoradionecrosis, and benign or malignant neoplasm can cause mandibular defect. Several techniques have been proposed for mandibular reconstruction along the past decades. In this article, we present and discuss a new modified method for accurate mandibular reconstruction. This method is mainly indicated in patients with benign mandibular tumors, where the resection margins can be more often anticipated prior to surgery. However, it is less useful for patients with malignant mandibular tumors, in whom resection margins are often finalized intraoperatively.

Navigation-guided lateral gap arthroplasty as the treatment of temporomandibular joint ankylosis.

PURPOSE: This article presents a novel method of navigation-guided lateral gap arthroplasty (LGA) in the treatment of temporomandibular joint ankylosis (TMJA). MATERIALS AND METHODS: Six patients with unilateral TMJA from 2007 through 2011 were included in this study. Presurgical planning was performed to determine the amount and extent of ankylosed bone to be resected using the simulation platform. Minimum follow-up was 6 months. Patients were monitored for complications and signs of recurrence. Maximum mouth opening (MO) was measured and compared intra- and postoperatively. RESULTS: Preoperative planning was performed at the STN or Accu-Navi workstation. The amount and extent of ankylosed bone to be resected was determined. All 6 LGAs were completed successfully using real-time instrument- and pointer-based navigation. Measurements performed intraoperatively showed that the mean for maximum MO was about 35 to 40 mm and remained the same postoperatively. Follow-up evaluation showed remarkable improvement in function and esthetics, with no signs of recurrence. CONCLUSION: Navigation-guided LGA can be regarded a viable option for performing this delicate and complicated surgical procedure.

Le Fort I osteotomy combined with endoscopic assistance for treatment of compound fracture of maxilla, zygoma, and orbital floor.

PURPOSE: The traditional surgery to reconstruct the compound fracture of the zygoma, maxilla, and orbital floor was usually open reduction and internal fixation using miniplate, and surgeons now can perform the endoscopic repair of relatively simple zygoma or orbital blowout fracture. In this study, we try to reconstruct midfacial complex fracture by combined application of intraoral approach and endoscopic-assisted minimally invasive method. METHODS: Six patients with traumatic midfacial fracture, including maxilla, zygoma, and orbital floor fracture, were selected. Intraoral Le Fort I osteotomy approach and endoscopic-assisted minimally invasive method were combined and applied to treat this complex midfacial fracture. RESULTS: The intraoral incision combined with endoscope offered suitable approach for reduction and fixation of fractured zygoma. The Le Fort I osteotomy could help to effectively reduce the fractured maxilla and offered useful operative approach for endoscope. The endoscope combined with a balloon catheter could successfully reconstruct the orbital floor fracture, and no intraoperative complications were encountered. The balloon catheter was removed 4 to 8 weeks after operation and did not lead to infection and obviously disrupt the healing of bone segments. The postoperative eye and occlusion function, evaluated by clinical examination, was satisfactory at 3 months. CONCLUSIONS: Although there are some limitations and strict indications, the advantages of this method may offer alternative choice for reconstruction of compound midfacial fracture.

Features and management of intracranial mandibular condyle dislocation after trauma.

BACKGROUND: Dislocation of the mandibular condyle into the middle cranial fossa is rare in clinics. It often occurs when the mouth is open wide during the injury. It causes restriction of mandibular motion, lower facial asymmetry, pain in the temporomandibular joint (TMJ), etc. OBJECTIVE: To introduce the features of intracranial mandibular condyle dislocation and discuss the management to this kind of trauma. MAJOR FINDINGS: In this paper, the authors present two cases, describing the diagnosis, surgical management, and 1-year follow-up evaluation. The results of the authors' treatment to intracranial mandibular condyle dislocation were satisfactory and stable, and no surgical complications were detected. CONCLUSION: Advanced imaging studies are mandatory for exact diagnosis and successful treatment of intracranial mandibular condyle dislocation, and individualized management is recommended.

A coaxial electrospun mat coupled with piezoelectric stimulation and atorvastatin for rapid vascularized bone regeneration.

The repair of critical bone defects caused by various clinical conditions needs to be addressed urgently, and the regeneration of large bone defects depends on early vascularization. Therefore, enhanced vascularization of artificial bone grafts may be a promising strategy for the regeneration of critical-sized bone defects. Taking into account the importance of rapid angiogenesis during bone repair and the potential of piezoelectric stimulation in promoting bone regeneration, novel coaxial electrospun mats coupled with piezoelectric materials and angiogenic drugs were fabricated in this study using coaxial electrospinning technology, with a shell layer loaded with atorvastatin (AVT) and a core layer loaded with zinc oxide (ZnO). AVT was used as an angiogenesis inducer, and piezoelectric stimulation generated by the zinc oxide was used as an osteogenesis enhancer. The multifunctional mats were characterized in terms of morphology, core-shell structure, piezoelectric properties, drug release, and mechanical properties, and their osteogenic and angiogenic capabilities were validated in vivo and ex vivo. The results revealed that the coaxial electrospun mats exhibit a porous surface morphology and nanofibers with a core-shell structure, and the piezoelectricity of the mats improved with increasing ZnO content. Excellent biocompatibility, hydrophilicity and cell adhesion were observed in the multifunctional mats. Early and rapid release of AVT in the fibrous shell layer of the mat promoted angiogenesis in human umbilical vascular endothelial cells (HUVECs), whereas ZnO in the fibrous core layer harvested bioenergy and converted it into electrical energy to enhance osteogenic differentiation of rat bone mesenchymal stem cells (BMSCs), and both modalities synergistically promoted osteogenesis and angiogenesis. Furthermore, optimal bone regeneration was achieved in a model of critical bone defects in the rat mandible. This osteogenesis-promoting effect was induced by electrical stimulation via activation of the calcium signaling pathway. This multifunctional mat coupling piezoelectric stimulation and atorvastatin promotes angiogenesis and bone regeneration, and shows great potential in the treatment of large bone defects.

Reconstruction of Dentomaxillofacial Deformity Secondary to Mandibular Defect Using Concomitant Orthognathic Surgery and Fibula Free Flap.

SUMMARY: The reconstruction of mandibular defects may be delayed or compromised for many reasons, especially in pediatric patients. With the growth of the remaining mandible and the maxilla in the malocclusion status, secondary dentomaxillofacial deformity is plausible. To treat the concomitant mandibular defect and secondary dentomaxillofacial deformity, a hierarchical algorithm using orthodontics, orthognathic surgery, and fibula free flap was developed. This retrospective case series included six patients with long-term mandibular defects caused by tumor resection without repair or with compromised costochondral reconstruction. All patients were treated using the same staged protocol, but with minor changes: (1) presurgical orthodontics, (2) virtual surgical planning, (3) fabrication of the guides and splints, (4) sequenced operations, and (5) postoperative care. The sequence of surgery included the Le Fort I osteotomy, mandibular sagittal split ramus osteotomy of the remaining ramus, final occlusion registration, repositioning of the distal segment of the mandible, segmented fibula reconstruction, and finally, the fixation of mandibular sagittal split ramus osteotomy. The operations and wound healing were uneventful in all patients, and no flap failure or severe complications were detected. Also, the patients exhibited no signs of temporomandibular joint ankylosis during the follow-up. The subspinale-nasion-supramental angle was significantly reduced after surgery. A significant improvement was detected in the facial contour symmetry measurements postoperatively. This proposed workflow of concomitant orthognathic surgery and the fibula free flap is effective and reliable for the reconstruction of dentomaxillofacial deformity secondary to the long-term mandibular defect.

Osteogenic differentiation of 3D-printed porous tantalum with nano-topographic modification for repairing craniofacial bone defects.

Introduction: Congenital or acquired bone defects in the oral and cranio-maxillofacial (OCMF) regions can seriously affect the normal function and facial appearance of patients, and cause great harm to their physical and mental health. To achieve good bone defect repair results, the prosthesis requires good osteogenic ability, appropriate porosity, and precise three-dimensional shape. Tantalum (Ta) has better mechanical properties, osteogenic ability, and microstructure compared to Ti6Al4V, and has become a potential alternative material for bone repair. The bones in the OCMF region have unique shapes, and 3D printing technology is the preferred method for manufacturing personalized prosthesis with complex shapes and structures. The surface characteristics of materials, such as surface morphology, can affect the biological behavior of cells. Among them, nano-topographic surface modification can endow materials with unique surface properties such as wettability and large surface area, enhancing the adhesion of osteoblasts and thereby enhancing their osteogenic ability. Methods: This study used 3D-printed porous tantalum scaffolds, and constructed nano-topographic surface through hydrothermal treatment. Its osteogenic ability was verified through a series of in vitro and in vivo experiments. Results: The porous tantalum modified by nano-topographic surface can promote the proliferation and osteogenic differentiation of BMSCs, and accelerate the formation of new bone in the Angle of the mandible bone defect of rabbits. Discussion: It can be seen that 3D-printed nano-topographic surface modified porous tantalum has broad application prospects in the repair of OCMF bone defects.

The Feasibility of Robot-Assisted Chin Osteotomy on Skull Models: Comparison with Surgical Guides Technique.

Surgical robotic technology is characterized by its high accuracy, good stability, and repeatability. The accuracy of mandibular osteotomy is important in tumor resection, function reconstruction, and abnormality correction. This study is designed to compare the operative accuracy between robot-assisted osteotomy and surgical guide technique in the skull model trials which simulated the genioplasty. In an experimental group, robot-assisted chin osteotomy was automatically performed in 12 models of 12 patients according to the preoperative virtual surgical planning (VSP). In a control group, with the assistance of a surgical guide, a surgeon performed the chin osteotomy in another 12 models of the same patients. All the mandibular osteotomies were successfully completed, and then the distance error and direction error of the osteotomy plane were measured and analyzed. The overall distance errors of the osteotomy plane were 1.57 ± 0.26 mm in the experimental group and 1.55 ± 0.23 mm in the control group, and the direction errors were 7.99 ± 1.10° in the experimental group and 8.61 ± 1.05° in the control group. The Bland-Altman analysis results revealed that the distance error of 91.7% (11/12) and the direction error of 100% (12/12) of the osteotomy plane were within the 95% limits of agreement, suggesting the consistency of differences in the osteotomy planes between the two groups. Robot-assisted chin osteotomy is a feasible auxiliary technology and achieves the accuracy level of surgical guide-assisted manual operation.

Modified Gap Arthroplasty for Temporomandibular Joint Ankylosis Following Radiotherapy for Rhabdomyosarcoma: Report of an Unusual Case and Brief Literature Review.

Radiotherapy at the temporomandibular joint (TMJ) area often results in trismus, however, post radiation ankylosis is extremely rare and has not been previously reported in literature. Radiation is known to impact the vasculature of bony structures leading to bone necrosis with certain risk factors including surgical intervention, even teeth extraction, that could lead to osteoradionecrosis. Accordingly, gap arthroplasty for such case seemed rather challenging. In this report, we introduce for the first time, a rare case of temporomandibular joint ankylosis post radiotherapy for management of rhabdomyosarcoma in a 12 years-old boy. A modified gap arthroplasty technique combined simultaneously with pterygo-masseteric muscle flap was applied to lower the risk of osteoradionecrosis due surgical trauma at irradiated area. Computed tomographic scan on the head indicated that the TMJ architecture was completely replaced by bone, with fusion of the condyle, sigmoid notch, and coronoid process to the zygomatic arch and glenoid fossa. The patient's problem was totally solved with no osteoradionecrosis or relapse of ankylosis observed at follow up visits. Herein, the modified gap arthroplasty combined with pterygo-masseteric muscle flap could be recommended to be applied on other cases of ankylosis especially after receiving radiotherapy.

Computer-assisted navigation: its role in intraoperatively accurate mandibular reconstruction.

OBJECTIVE: This article presents our experiences of computer-assisted navigation in mandibular reconstruction and evaluates its effectiveness. STUDY DESIGN: Eight patients who underwent navigation-guided mandibular reconstruction with a fibula free flap were reviewed. Under intraoperative navigation, the ideal positions of the mandibular angles and condyles were confirmed by the navigation probe. The surgical results were evaluated through postoperative panoramic radiographs, coronal computed tomography scans, and image fusion. RESULTS: Navigation-guided mandibular reconstructions were successfully completed on the basis of preoperative planning and simulation. The surgical discrepancy in the mandibular angle between the actual surgical results and the preoperative designs was 1.92 ± 0.97 mm. Panoramic radiographs and coronal computed tomography scans illustrated that all the condyles fitted into their glenoid fossae. All patients were satisfied with their functional and aesthetic outcomes. CONCLUSIONS: Computer-assisted navigation is a viable technology for improving surgical outcomes in mandibular reconstruction, which can assist the surgeons by providing real-time three-dimensional surgical references during the operation.

An excellent navigation system and experience in craniomaxillofacial navigation surgery: a double-center study.

Numerous problems regarding craniomaxillofacial navigation surgery are not well understood. In this study, we performed a double-center clinical study to quantitatively evaluate the characteristics of our navigation system and experience in craniomaxillofacial navigation surgery. Fifty-six patients with craniomaxillofacial disease were included and randomly divided into experimental (using our AccuNavi-A system) and control (using Strker system) groups to compare the surgical effects. The results revealed that the average pre-operative planning time was 32.32 mins vs 29.74 mins between the experimental and control group, respectively (p > 0.05). The average operative time was 295.61 mins vs 233.56 mins (p > 0.05). The point registration orientation accuracy was 0.83 mm vs 0.92 mm. The maximal average preoperative navigation orientation accuracy was 1.03 mm vs 1.17 mm. The maximal average persistent navigation orientation accuracy was 1.15 mm vs 0.09 mm. The maximal average navigation orientation accuracy after registration recovery was 1.15 mm vs 1.39 mm between the experimental and control group. All patients healed, and their function and profile improved. These findings demonstrate that although surgeons should consider the patients' time and monetary costs, our qualified navigation surgery system and experience could offer an accurate guide during a variety of craniomaxillofacial surgeries.