Reciprocating Rasp for Use in Mandibular Anterior Subapical Osteotomy.

The article describes a reciprocating rasp used in the mandibular anterior subapical osteotomy. Over the past 2 years, reciprocating rasp osteotomy was introduced in the Oral and Craniomaxillofacial Surgery Department of Shanghai Ninth People's Hospital. No complication such as bleeding, wound infection, or tissue necrosis has been encountered. The use of reciprocating rasp avoids iatrogenic damage to adjacent structures and reduces the time spent operating mandibular anterior subapical osteotomy. Therefore, it is recommended for mandibular anterior subapical osteotomy.

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.

Dlx2 overexpression enhanced accumulation of type II collagen and aggrecan by inhibiting MMP13 expression in mice chondrocytes.

Genetic studies revealed a crucial role of Distal-homebox (Dlx) genes in skeletal development, and our previous study demonstrated overexpressing Dlx2 in neural crest cells led to abnormal cartilage structure, including ectopic cartilage in the maxillary region and nasal bone in mice. The aim of this study was to investigate how Dlx2 overexpression affects chondrogenesis in mouse chondroblast cell line TMC23 and the underlying mechanism. We first demonstrated that Dlx2 expression was upregulated during chondrogenesis in TMC23 cells. Moreover, forced overexpression of Dlx2 in TMC23 cells led to increased accumulation of aggrecan and type II collagen, markers of early chondrocyte differentiation, but had little effect on mRNA and protein levels of Aggrecan and Col2α1, type II collagen gene. Importantly, Dlx2 overexpression decreased mRNA and protein levels of MMP13, a major collagenase degrading aggrecan and type II collagen during late stages of chondrogenesis. Luciferase-reporter and Chromatin-immunoprecipitation analysis demonstrated that MMP13 promoter contained two Dlx2-response elements, and Dlx2 inhibited MMP13 expression by directly binding to these two elements. Based on these observations, we propose that forced overexpression of Dlx2 enhances early chondrocyte differentiation by increasing accumulation of type II collagen and aggrecan, but interferes later stages of chondrocyte differentiation through inhibiting MMP13 expression.

Segmental Maxillary Distraction Osteogenesis With a Hybrid-Type Distractor in the Management of Wide Alveolar Cleft.

OBJECTIVE: To investigate segmental maxillary distraction osteogenesis (DO) with hybrid-type distractor in the management of wide alveolar cleft. PATIENTS AND METHODS: Six patients underwent segmental DO with a hybrid-type distractor. After the success of DO and 3-month consolidation period, removal of the distractor was accompanied by alveolar bone graft with iliac bone. Panoramic radiograph and computed tomography scanning were taken preoperatively (T0) and the day after distractor removal (T1). The crest distance between the long axis of cleft nearby teeth was measured. RESULT: All patients completed the DO period, and the succeeding alveolar bone graft healing was uneventful. The mean cleft distance decrease was 12.05 mm (range: 10.1-13.5 mm). As for the mobility degree record of abutment tooth in the transport segment recorded, 6 patients were grading I° at T0, while 5 patients were grading I° and 1 patient was grading II° at T1. CONCLUSION: Segmental maxillary DO with the hybrid-type distractor is successful to reduce the cleft width in these cases, and it is promising in the treatment of wide dental alveolar cleft, especially for the adult patient.

Computer-Assisted Distraction Osteogenesis in the Treatment of Hemifacial Microsomia.

PURPOSE: To investigate the application of computer-assisted surgical planning and virtual guide in distraction osteogenesis for patients with hemifacial microsomia. METHODS: Eight patients diagnosed with unilateral hemifacial microsomia were enrolled in this study. Preoperative surgical planning and simulation were performed on three-dimensional model. Distraction was simulated on virtual model and the new morphology of the mandible was predicted. Mandibular ramus osteotomy and distractor implant was performed under the guidance of tooth-borne virtual guide. Postoperative evaluation of the intervention was performed by comparison of surgical planning and actual result. RESULTS: Preoperative planning, simulation, osteotomy and distractor implant under the guidance of virtual guide were performed successfully on all patients. Tooth-borne guide defined the osteotomy line and accurate position of distractor. Facial symmetry was greatly improved. The osteogenesis and neomandible contour was checked by postoperative computed tomography, and a good matching with the preoperative planning was achieved. CONCLUSIONS: Computer-assisted surgical planning and intraoperative virtual guide shows its great value in improving the accuracy of distraction osteogenesis and restoring facial symmetry. It is regarded as a valuable technique in this potentially complicated procedure.

Interdisciplinary Surgical Management of Multiple Facial Fractures With Image-Guided Navigation.

PURPOSE: To evaluate the effectiveness of interdisciplinary surgical management of multiple facial fractures with image-guided surgical navigation. PATIENTS AND METHODS: From 2011 through 2014, 36 patients with multiple facial fractures were enrolled in the study. With individual virtual 3-dimensional (3D) modeling, interdisciplinary planning and surgical simulation were carried out on an Accu-Navi software platform. Through an interactive collaboration among specialists, all patients underwent 1-stage open reduction under guidance of the navigation system. The outcome was assessed by superimposing the postoperative 3D computed tomographic (CT) model on the preoperative plan and clinical examination. RESULTS: Through the registration procedure, an accurate match between the actual intraoperative position and the CT images was achieved within a systematic error of 1 mm. The fractured bone segments were released and repositioned according to the preoperative plan and simulation with the aid of instrument- and probe-based navigation. All patients underwent uneventful healing without serious complications. Postoperative assessment of surgical intervention showed a quantitative discrepancy less than 2 mm (1.49 ± 0.27), showing a satisfactory concordance. CONCLUSION: In the interdisciplinary surgical management of multiple facial fractures, image-guided surgical navigation, including preoperative planning, surgical simulation, postoperative assessment, and computer-assisted navigation, proved an optimal strategy and valuable option for this potentially complicated procedure.

A correlational study of serum alkaline phosphatase level and developmental mandibular laterognathism.

The abnormal cartilage/bone metabolism in unilateral condyle may be a direct factor that contributes to developmental mandibular laterognathism. However, although many molecules have been demonstrated to play crucial roles in the development of temporomandibular joints, the exact molecular mechanisms that lead to the disrupted condylar cartilage/bone development were greatly unknown. In this retrospective study, our findings revealed that serum alkaline phosphatase (ALP) level in adult patients with developmental mandibular laterognathism was lower than that in control subjects, and the serum ALP levels continue to reduce in adult patients (>20 years old). Although the exact relationship between the lower serum ALP level and developmental mandibular laterognathism is unclear, the findings further support the opinion that the condylar growth may sustain for a long time in the affected condyle in patients with developmental mandibular laterognathism and offer an alternative choice to use total serum ALP activity as a possible biomarker to assess condylar growth activity in patients with developmental mandibular laterognathism.

Computer-Aided Design and Computer-Aided Manufacturing Hydroxyapatite/Epoxide Acrylate Maleic Compound Construction for Craniomaxillofacial Bone Defects.

The aim of this study was to investigate the use of computer-aided design and computer-aided manufacturing hydroxyapatite (HA)/epoxide acrylate maleic (EAM) compound construction artificial implants for craniomaxillofacial bone defects. Computed tomography, computer-aided design/computer-aided manufacturing and three-dimensional reconstruction, as well as rapid prototyping were performed in 12 patients between 2008 and 2013. The customized HA/EAM compound artificial implants were manufactured through selective laser sintering using a rapid prototyping machine into the exact geometric shapes of the defect. The HA/EAM compound artificial implants were then implanted during surgical reconstruction. Color-coded superimpositions demonstrated the discrepancy between the virtual plan and achieved results using Geomagic Studio. As a result, the HA/EAM compound artificial bone implants were perfectly matched with the facial areas that needed reconstruction. The postoperative aesthetic and functional results were satisfactory. The color-coded superimpositions demonstrated good consistency between the virtual plan and achieved results. The three-dimensional maximum deviation is 2.12 ±â€Š0.65  mm and the three-dimensional mean deviation is 0.27 ±â€Š0.07  mm. No facial nerve weakness or pain was observed at the follow-up examinations. Only 1 implant had to be removed 2 months after the surgery owing to severe local infection. No other complication was noted during the follow-up period. In conclusion, computer-aided, individually fabricated HA/EAM compound construction artificial implant was a good craniomaxillofacial surgical technique that yielded improved aesthetic results and functional recovery after reconstruction.

Irf6-Related Gene Regulatory Network Involved in Palate and Lip Development.

Numerous genes including Irf6 have been revealed to contribute to cleft lip with or without cleft palate (CL/P). In this study, we performed a systematic bioinformatics analysis of Irf6-related gene regulatory network involved in palate and lip development by using GeneDecks, DAVID, STRING, and GeneMANIA database. Our results showed that many CL/P candidate genes have relation with Irf6, and 9 of these genes, including Msx1, Pvrl1, Pax9, Jag2, Irf6, Tgfb3, Rara, Gli2, and Tgfb2, were enriched into the CL/P gene group. Some of these 9 genes also were commonly involved in different signaling pathways and different biological processes, and they also have protein-protein interactions with Irf6. These findings make us analyze the intricate function of Irf6 in a CL/P gene regulatory network, followed by guiding us to perform further functional studies on these genes in the future. This method also offers us a simple, cheap, but useful method to analyze the relationship with a gene regulatory network of a certain disease such as CL/P.

Le Fort II midfacial distraction combined with orthognathic surgery in the treatment of nasomaxillary hypoplasia.

Patients with nasomaxillary hypoplasia have severe facial concavity and compromised skeletal class III malocclusion. Its treatment is still a challenge to surgeons. Our aim was to evaluate the combination of midfacial distraction and orthognathic surgery in the treatment of nasomaxillary hypoplasia. Four patients with nasomaxillary hypoplasia were enrolled in this study. After Le Fort II osteotomy, the rotational distraction of nasomaxillary complex was performed to rehabilitate facial convexity. Then bilateral sagittal split ramus osteotomy with or without Le Fort I osteotomy was used to correct malocclusion. All patients healed uneventfully, and the maxillae moved forward conspicuously. No obvious pain and severe discomfort were complained during distraction. A significant advancement and downward movement of the maxilla were shown by cephalometric analysis. The combination of midfacial distraction and orthognathic surgery provides us an ideal alternative in the treatment of nasomaxillary hypoplasia.

Bioinformatic analysis of Msx1 and Msx2 involved in craniofacial development.

Msx1 and Msx2 were revealed to be candidate genes for some craniofacial deformities, such as cleft lip with/without cleft palate (CL/P) and craniosynostosis. Many other genes were demonstrated to have a cross-talk with MSX genes in causing these defects. However, there is no systematic evaluation for these MSX gene-related factors. In this study, we performed systematic bioinformatic analysis for MSX genes by combining using GeneDecks, DAVID, and STRING database, and the results showed that there were numerous genes related to MSX genes, such as Irf6, TP63, Dlx2, Dlx5, Pax3, Pax9, Bmp4, Tgf-beta2, and Tgf-beta3 that have been demonstrated to be involved in CL/P, and Fgfr2, Fgfr1, Fgfr3, and Twist1 that were involved in craniosynostosis. Many of these genes could be enriched into different gene groups involved in different signaling ways, different craniofacial deformities, and different biological process. These findings could make us analyze the function of MSX gens in a gene network. In addition, our findings showed that Sumo, a novel gene whose polymorphisms were demonstrated to be associated with nonsyndromic CL/P by genome-wide association study, has protein-protein interaction with MSX1, which may offer us an alternative method to perform bioinformatic analysis for genes found by genome-wide association study and can make us predict the disrupted protein function due to the mutation in a gene DNA sequence. These findings may guide us to perform further functional studies in the future.

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.

Accurate movement of jaw segment in virtual 3D orthognathic surgery.

In traditional virtual 3D orthognathic surgery, after repositioning the maxillary segment to the desired position, surgeons usually roughly rotate or adjust the mandibular segment to obtain a relatively good relationship with maxillary dentition to calculate the virtual terminal occlusion splint. However, surgeons are not easy to avoid penetrability, overlap, or an overly large space existing between the maxillary and mandibular dentitions during this process. The present report offered a new method to obtain a suitable virtual terminal occlusal splint that could avoid penetrability, overlap, or an overly large space between the maxillary and mandibular dentitions, and simultaneously accurately moving the maxillary or mandibular segment to the desired position utilizing the planned terminal occlusion plaster models in virtual orthognathic surgery. For double jaw surgery, after aligning the planned plaster models to the 3D maxilla and mandible, we could simultaneously move the maxillary and mandibular segment as a whole that maintain the planned terminal occlusion to the desired position. This present method may enhance the accuracy of 3D virtual orthognathic surgery and save plenty of time spend on virtual surgery simulation, which also offers a useful educational method for training junior surgeons and students.

Endoscope-assisted conservative condylectomy combined with orthognathic surgery in the treatment of mandibular condylar osteochondroma.

Mandibular condylar osteochondroma (OC) results in asymmetric prognathism with facial morphologic and functional disturbance. The aim of this study was to explore the feasibility of endoscope-assisted conservative condylectomy combined with simultaneous orthognathic surgery in the treatment of condylar OC. Thirteen patients with OC of the mandibular condyle were enrolled in this study. With the aid of endoscope, condylar OC resection and conservative condylectomy were carried out via intraoral approach. A direct vision of the magnified and illuminated operative field was realized. Simultaneous orthognathic surgery was used to correct facial asymmetry and malocclusion. All patients healed uneventfully. No facial nerve injury and salivary fistula occurred. Facial symmetry and morphology were greatly improved, and stable occlusion was obtained in all cases. The patients showed no signs of recurrence and temporomandibular joint ankylosis in the 16 to 54 months of follow-up. Endoscope-assisted tumor resection and condylectomy combined with simultaneous orthognathic surgery provide us a valuable option in the treatment of mandibular condylar OC.

Rapid and accurate identification of cut ends of facial nerves using a nerve monitoring system during surgical exploration and anastomosis.

PURPOSE: Surgical exploration and end-to-end neurorrhaphy is the preferred management for traumatic facial nerve injury. Traditionally, finding the cut ends of facial nerves depends mainly on a surgeon's experience. In this study, a nerve monitoring system to help the surgeon quickly and accurately identify, confirm, and locate the cut ends of facial nerve branches was investigated. PATIENTS AND METHODS: Six patients with traumatic facial nerve injury were selected, and the nerve monitoring system was applied during the surgical process of facial nerve exploration and anastomosis. Operation time and surgical outcome were used to evaluate the effect of this method. RESULTS: The surgical procedures required 6 to 15 minutes (mean, 10 minutes) for detecting and dissecting each cut end of a facial nerve branch. All cut ends of injured facial nerve branches were found during surgery in all 6 patients, and no intraoperative complications were encountered. The postoperative function of the facial nerve, evaluated by clinical examination and diagnostic electroneurography, was satisfactory and symmetrical in all 6 patients at 3 months. CONCLUSION: Using a nerve monitoring system could effectively help surgeons achieve rapid and accurate identification of the cut ends of facial nerves during surgical facial nerve exploration for traumatic facial nerve injury.

Piezoelectric decortication applied in periodontally accelerated osteogenic orthodontics.

Our aim was to evaluate the application of piezoelectric decortication in periodontally accelerated osteogenic orthodontics (PAOO). One hundred fifty-six patients with severe skeletal malocclusions were enrolled in this study. Ultrasonic decortications were performed in 187 labial or lingual PAOO of the maxillary and mandibular anterior teeth. Orthodontic decompensation started from the fifth day after operation. All patients healed uneventfully and no severe periodontic complications were recorded. Rapid teeth movement and relatively short treatment duration were realized. Alveolar fenestration and bony dehiscence was successfully addressed. With physical and mechanical properties of absence of macrovibration, ease of use and control, piezosurgery showed its great values in PAOO.

Presurgical motivations, self-esteem, and oral health of orthognathic surgery patients.

PURPOSE: The aim of this study was to evaluate motivations, self-esteem, and oral health for undergoing orthognathic patients by gender in China before orthognathic surgery. PATIENTS AND METHODS: Using a prospective and control study design, 429 subjects in China were collected from December 2010 to May 2011. The patient group consisted of 210 consecutive healthy patients, and 219 young individuals comprised the control group. All the subjects filled out a questionnaire and were assessed by Self-esteem Scale and Oral Health Impact Profile validated for Chinese patients before surgery. To measure the discrepancy, the Student t test was computed. P <0.05 was considered significant. RESULTS: In China, major motivations for orthognathic surgery are to improve facial appearance (83.33%), occlusion (50%), and self-confidence (48.1%). Females expect to improve facial appearance (83.87%), self-confidence (43.55%), and occlusion (41.94%). Males are for the improvement of facial appearance (82.56%), occlusion (63.95%), and self-confidence (54.65%). Self-esteem in the patient group is obviously lower (P < 0.01). There is a significant difference of self-esteem in female groups (P < 0.01), but none in male groups. Statistically significant differences were observed on oral health between both sexes. CONCLUSIONS: (1) Special attention should be paid on patients' ethnic, economic, cultural, and social aspects. In Chinese orthognathic patients, improving facial appearance is the primary motivation. Self-confidence has been more frequently mentioned, while headache far less than other countries. (2) Female patients have less self-esteem than females in the control group. (3) Patients' oral health are worse than those in the control group.

A novel method to determine the potential rotational axis of the mandible during virtual three-dimensional orthognathic surgery.

During virtual three-dimensional orthognathic surgery in cases where an overlap or penetrability occurs between the 2 jaws due to the repositioning of the maxillary segment, it is necessary to establish a vertical opening of the mandible to obtain a relatively good relationship with the maxillary segment for the fabrication of an intermediate occlusal splint. However, there are few reports that address the precise definition of the rotational axis of the mandible during virtual surgery. Here, we present the idea that the mandible's movement during virtual three-dimensional orthognathic surgery is similar to hinge movement in vivo and developed a method for locating the geometric center of the three-dimensional condyle using Hypermesh software combined with Mimics software. Subsequently, we defined the rotational axis of the mandible based on the located geometric centers of the bilateral condyles, and the mandible was then rotated around the defined axis from the retruded contact position to mimic the hinge movement. Preliminary results indicated that the presented method could approximately mimic the hinge movement of the mandible with a relatively high accuracy in a three-dimensional environment, which may improve the accuracy of virtual intermediate occlusal splint.

Moving the mandible to the retruded contact position for simulating the hinge movement in virtual three-dimensional orthognathic surgery by integrating the plaster models.

The range of rotation of the mandible during virtual three-dimensional orthognathic surgery is small and may be similar to the hinge movement of the mandible. This current study offers a new method to move the mandible to the retruded contact position (RCP), a position of beginning hinge movement, during virtual three-dimensional orthognathic surgery. During this method, a three-dimensional skull model was reconstructed from the computed tomographic images in the Mimics software. Then the RCP in the patient could be obtained using Gothic arch tracer or swallowing method and was recorded using a wax plate, followed by transferring to plaster models. Subsequently, the plaster models in RCP were scanned using a dental surface scanner and imported into the Mimics software. Finally, we could move the mandible to the RCP based on the registration between the three-dimensional skull model and plaster model for simulating the hinge movement during virtual three-dimensional orthognathic surgery. This may be a small step forward for improving the accuracy of virtual three-dimensional orthognathic surgery.

Comparative study of different osteotomy modalities in maxillary distraction osteogenesis for cleft lip and palate.

PURPOSE: Conventional maxillary distraction osteogenesis and anterior maxillary segmental distraction were applied in the treatment of severe maxillary hypoplasia secondary to cleft clip and palate. The aim of the present study was to compare the difference between these 2 osteotomy modalities used for rigid external distraction. PATIENTS AND METHODS: Ten patients with severe maxillary hypoplasia secondary to CLP were enrolled in our study. They were randomly divided into 2 groups. Conventional maxillary distraction osteogenesis was performed in 5 patients and anterior maxillary segmental distraction in 5 patients. The preoperative and postoperative lateral cephalograms were compared, and cephalometric analysis was performed. The independent sample t test was used to evaluate the differences between the 2 groups. RESULTS: All patients healed uneventfully, and the maxillae moved forward satisfactorily. The sella-nasion-point A angles, nasion-point A-Frankfort horizontal plane angles, overjets, and 0-meridian to subnasale distances had increased significantly after distraction osteogenesis. Significant differences were found in the changes in palatal length between the 2 groups (P < .05). A mean increase of 7.50 mm in palatal length was found in the anterior maxillary segmental distraction group. No significant difference in the changes in palatopharyngeal depth or soft palatal length was found. CONCLUSIONS: With the ability of increasing the palatal and arch length, avoiding changes in palatopharyngeal depth, and preserving palatopharyngeal closure function, anterior maxillary segmental distraction has great value in the treatment of maxillary hypoplasia secondary to CLP. It is a promising and valuable technique in this potentially complicated procedure.