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.

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.

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.

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.

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.

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.

CBCT combining with plaster models: application in virtual three-dimensional subapical segmental osteotomy to obtain more precise occlusal splint.

Anterior subapical segmental osteotomy is considered to be an important surgical technique to obtain functional occlusion and improve the facial profile for patients with maxillary and mandibular protrusion or retrusion, and some complications, such as ischemic necrosis of the distal segment, devitalization of the teeth adjacent to the osteotomy site, and inadequate movement space of segment for obtaining a good occlusion or facial profile, usually exist during surgery. Imprecise measurement of root length, interradicular distance, and intertooth distance based on traditional panoramic radiography that demonstrated existing horizontal distortion and vertical distortion may play an important role in resulting in these problems. In addition, the root is invisible for surgical simulation in traditional plaster models. The recently developed cone-beam computed tomography (CBCT) presents a higher spatial resolution with a lower radiation dose, simultaneously with excellent accuracy and without magnification of images. The presented technique was used to obtain a precise occlusal splint in virtual 3D subapical segmental osteotomy by combining CBCT with plaster models that could guarantee the measurement accuracy of root length, interradicular distance, and intertooth distance, followed by the result of fewer tooth root damage and more precise forecasting of available movement space of jaw segment. Combining with other advantages of virtual 3D surgery, such as precise teeth surface of plaster models, soft tissue simulation, genoplasty simulation, and zygoma plasty simulation, this presented technique may offer a preferable method to patients who need subapical segmental osteotomy.

Distraction osteogenesis combined with tissue-engineered cartilage in the reconstruction of condylar osteochondral defect.

PURPOSE: Surgical rehabilitation of condylar osteochondral defect remains a challenge for surgeons. The aim of this study was to explore the feasibility of combining distraction osteogenesis with tissue-engineered cartilage in the reconstruction of condylar osteochondral defect. MATERIALS AND METHODS: A condylar defect model was established in 18 goats that were randomly divided into 2 groups: the experimental group and the control group. Mandibular ramus osteotomies were performed and distractors were implanted in all animals. The mixture of chondrocytes and Pluronic F-127 (Sigma-Aldrich, St Louis, MO) was injected on the notched surface of a transport disc in the experimental group, whereas a scaffold without cells was transplanted into the control group. After a 5-day latency period, distraction was activated at a rate of 0.5 mm twice per day for 15 days. The goats were killed at the end of the fourth, eighth, or twelfth week in the consolidation period. Specimens were harvested and macroscopic evaluation, as well as Masson trichrome and immunohistochemical staining, were performed to compare the results between the 2 groups. RESULTS: Osteogenesis was found in all animals with no evidence of infection. Condyle-like structures were formed at the upper end of the transport segment in all animals. The neocondylar surface was covered with a layer of smooth lustrous fibrocartilage in the experimental group. Collagen was shown in the reparative tissue by Masson trichrome staining. Immunohistochemistry staining indicated that type II collagen was positive, whereas type I collagen was negative on the neocondylar surface in the experimental group. No cartilage-like tissue was seen, but fibrous tissue was identified at the bony surface in the control group. In the experimental group, immunofluorescent semiquantitative analysis showed that the positive rate of type II collagen was 1.62% ± 0.53% after the fourth week of consolidation, and it increased to 12.39% ± 3.27% after the twelfth week. There was a significant difference in the expression of type II collagen between the goats examined after the fourth week, and those examined after the twelfth week. CONCLUSION: The combination of distraction osteogenesis with tissue-engineered cartilage is an ideal alternative in the reconstruction of condylar osteochondral defect. By use of this method, the simultaneous rehabilitation and regeneration of condylar bone and cartilage were achieved.

Preliminary study of virtual orthognathic surgical simulation and training.

BACKGROUND AND OBJECTIVE: Virtual surgical simulation and training system offers a cost-effective and efficient alternative to traditional training and surgical planning. However, the algorithm for surgical simulation is sophisticated, and the requirement of computer software and hardware is high. The objective of this study was to explore the feasibility of tree-structure architectonic model in simplifying and realizing virtual orthognathic surgical simulation. METHODS: Four patients with skeletal malocclusions were enrolled in this study. Craniomaxillofacial computed tomography scan was obtained, and three-dimensional model was reconstructed using Simplant software. Maxillary Le Fort I osteotomy, bilateral sagittal split ramus osteotomy, vertical ramus osteotomy, and genioplasty were carried out on the three-dimensional model in advance. Tree-structure architectonic model was established in the sterolithography format. With stereoscopic glasses, using digital gloves, operators immersed in virtual environment and operated on "real" patients performing surgical simulation. RESULTS: Through establishing tree-structure architectonic model in advance, the complex algorithm for virtual osteotomy was simplified, and computational complexity was reduced. Three-dimensional model can be visualized from any viewing point. Operators were immersed in the virtual environment with a conspicuous sense of immersion. An obvious image and tactile feedback was perceived when touching and moving the bony segments. Virtual orthognathic surgical simulation and training were realized with real-time image and tactile perception feedback. CONCLUSIONS: Establishing tree-structure architectonic model in advance is an ideal alternative in implementing virtual orthognathic surgical simulation. Virtual surgical simulation and training were realized with a strong sense of immersion. Craniomaxillofacial three-dimensional virtual surgical simulation system can be used in orthognathic surgical planning, simulation, and operation training.

Sequential maxillary bifocal transport distraction osteogenesis after radiotherapy.

Maxillary defects secondary to ablative surgery are common, and functional maxillary reconstruction is challenging. Adjuvant radiotherapy further complicates reconstructive surgical planning. In this article, successful functional reconstruction of a partial maxillary defect was achieved using segmental osteotomy, sequential bifocal distraction osteogenesis, and prosthodontic treatment. The current evidence is reviewed, and the surgical planning and technique are described in detail.

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.

A Self-Supervised Deep Framework for Reference Bony Shape Estimation in Orthognathic Surgical Planning.

Virtual orthognathic surgical planning involves simulating surgical corrections of jaw deformities on 3D facial bony shape models. Due to the lack of necessary guidance, the planning procedure is highly experience-dependent and the planning results are often suboptimal. A reference facial bony shape model representing normal anatomies can provide an objective guidance to improve planning accuracy. Therefore, we propose a self-supervised deep framework to automatically estimate reference facial bony shape models. Our framework is an end-to-end trainable network, consisting of a simulator and a corrector. In the training stage, the simulator maps jaw deformities of a patient bone to a normal bone to generate a simulated deformed bone. The corrector then restores the simulated deformed bone back to normal. In the inference stage, the trained corrector is applied to generate a patient-specific normal-looking reference bone from a real deformed bone. The proposed framework was evaluated using a clinical dataset and compared with a state-of-the-art method that is based on a supervised point-cloud network. Experimental results show that the estimated shape models given by our approach are clinically acceptable and significantly more accurate than that of the competing method.