Relationship between prognosis and different surgical treatments of zygomatic defects: A retrospective study / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the effect and summarize the characteristics of different treatment methods in repairing zygomatic defect.@*METHODS@#A total of 37 patients with zygomatic defect were reviewed in the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from August 2012 to August 2019. According to the anatomical scope of defect, the zygomatic defects were divided into four categories: Class 0, the defect did not involve changes in zygomatic structure or continuity, only deficiency in thickness or projection; Class Ⅰ, defect was located in the zygomatic body or involved only one process; Class Ⅱ, a single defect involved two processes; Class Ⅲa, referred to a single defect involving three processes and above; Class Ⅲb, referred to zygomatic defects associated with large maxillary defects. The etiology, defect time, defect size and characteristics of zygomatic defects, the repair and reconstruction methods, and postoperative complications were collected and analyzed. Postoperative computed tomography (CT) data were collected to evaluate the outcome of zygomatic protrusion. Chromatographic analysis was used to assess the postoperative stability.@*RESULTS@#Among the causes of defects, 25 cases (67.57%) were caused by trauma, and 11 cases (29.73%) were of surgical defects following tumor resection. We performed autologous bone grafts in 19 cases, 6 cases underwent vascularized tissue flap, 5 cases underwent external implants alone, and 7 cases underwent vascularized tissue flap combined with external implants. After the recovery of the affected side, the average difference of the zygomatic projection between the navigation group and the non-navigation group was 0.45 mm (0.20-2.50 mm) and 1.60 mm (0.10-2.90 mm), with a significant difference (P=0.045). Two patients repaired with titanium mesh combined with anterolateral thigh flap had obvious deformation or fracture of titanium mesh; 2 patients with customized casting prosthesis had infection after surgery and fetched out the prosthesis finally.@*CONCLUSION@#Autologous free grafts or alloplastic materials may be used in cases without significant structural changes. Pedicle skull flap or vascularized bone tissue flap is recommended for zygomatic bone defects with bone pillar destruction, chronic inflammation, oral and nasal communication or significant soft tissue insufficiency. Titanium mesh can be used to repair a large defect of zygomatic bone, and it is suggested to combine with vascularized bone flap transplantation.

Three-dimensional finite element analysis of traumatic mechanism of mandibular symphyseal fracture combined with bilateral intracapsular condylar fractures / 北京大学学报(医学版)

OBJECTIVE@#To analyze the biomechanical mechanism of mandibular symphyseal fracture combined with bilateral intracapsular condylar fractures using finite element analysis (FEA).@*METHODS@#Maxillofacial CT scans and temporomandibular joint (TMJ) MRI were performed on a young male with normal mandible, no wisdom teeth and no history of TMJ diseases. The three-dimensional finite element model of mandible was established by Mimics and ANSYS based on the CT and MRI data. The stress distributions of mandible with different angles of traumatic loads applied on the symphyseal region were analyzed. Besides, two models with or without disc, two working conditions in occlusal or non-occlusal status were established, respectively, and the differences of stress distribution between them were compared.@*RESULTS@#A three-dimensional finite element model of mandible including TMJ was established successfully with the geometry and mechanical properties to reproduce a normal mandibular structure. Following a blow to the mandibular symphysis with different angles, stress concentration areas were mainly located at condyle, anterior border of ramus and symphyseal region under all conditions. The maximum equivalent stress always appeared on condylar articular surface. As the angle between the external force and the horizontal plane gradually increased from 0° to 60°, the stress on the mandible gradually concentrated to symphysis and bilateral condyle. However, when the angle between the external force and the horizontal plane exceeded 60°, the stress tended to disperse to other parts of the mandible. Compared with the condition without simulating the disc, the stress distribution of articular surface and condylar neck decreased significantly when the disc was present. Compared with non-occlusal status, the stress on the mandible in occlusal status mainly distributed on the occlusal surface, and no stress concentration was found in other parts of the mandible.@*CONCLUSION@#When the direction of external force is 60° from the horizontal plane, the stress distribution mainly concentrates on symphyseal region and bilateral condylar surface, which explains the occurrence of symphyseal fracture and intracapsular condylar fracture. The stress distribution of condyle (including articular surface and condylar neck) decreases significantly in the presence of arti-cular disc and in stable occlusal status when mandibular symphysis is under traumatic force.

Application of computer-aided virtual mandibular position in the simultaneous treatment of children with temporomandibular joint ankylosis and jaw deformity / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the feasibility of computer-aided design virtual mandibular position in the simultaneous treatment of children with temporomandibular joint ankylosis (TMJA) and jaw deformity.@*METHODS@#The children with unilateral TMJA were surgically treated from January 2016 to June 2017 in the Department of Oral and Maxillofacial Surgery. The image data of jaw and dentition were imported into the computer software to simulate the surgical procedure. An osteotomy of the affected side was performed to remove ankylosed bone mass. Then the mandible was rotated around the unaffected condyle to eliminate the chin deviation by the virtual plan. An open bite was thus created on the affected side to provide space for vertical midfacial growth. In the virtual mandibular position, the affected ramus was reconstructed with costochondral grafting. Finally, digital occlusal splint was designed and prefabricated by 3D printing. During surgery, temporomandibular joint ankylosis was released and mandibular position was guided in place by the digital occlusal splint. In the new mandibular position, costochondral grafting was completed. After the surgery, the occlusal splint was wired to the mandibular dentition and would be gradually adjusted by grinding off the maxillary side to promote downward growth of the maxilla until the open bite was eliminated. The ramus height and chin deviation were measured before and one week after the surgery to validate the method. Comparisons of the measurements were made by means of a repeatedmeasures analysis of variance (ANOVA) (P=0.05). Pairwise multiple comparisons were conducted using the Bonferroni correction (P=0.05).@*RESULTS@#Five patients were included in this study. Under the guidance of the digital occlusal splint, the mandible could reach the preoperative designed position smoothly in all the cases. The chin deviations were (0.58±0.20) mm in the virtual plan before surgery, and (0.70±0.27) mm after surgery, which were not significant statistically (P>0.05). The ramus heights on the affected side were (48.19±3.20) mm in the virtual plan before surgery, and (48.17±3.62) mm after surgery, which were not significant statistically (P>0.05).@*CONCLUSION@#It is feasible and reliable in the simultaneous treatment of TMJA with jaw deformity under the guidance of virtual mandibular position.

Application of intermaxillary fixation screws in the treatment of oral and maxillofacial bone fracture / 实用口腔医学杂志

Objective: To evaluate the clinical results of intermaxillary fixation screws used in the management of oral and maxillofacial bone fracture. Methods: The clinical and imaging data of 166 cases of oral and maxillofacial bone fractures treated by intermaxillary fixation screws were analyzed retrospectively with the implant location,numbers and the complications of the treatment. Results: 668 intermaxillary fixation screws were used in the 166 cases,at an average of 4 screws per case. The occlusal relationship of the patients was perfect after 1 week traction. Radiographs showed 105 screws (15. 7％) reached the superficial layer of dentin,middle or deep layer in 14 cases (2. 1％),and root canal injury in 2 cases(1. 2％). No intermaxillary fixation screw was broken,loosened or fallen off. Conclusion: Intermaxillary fixation screws can be effectively used in the management of oral and maxillofacial bone fracture. For the most cases,4-6 screws can meet the needs. Root injuries and other complications should be avoided.

Surgical treatment for incomplete Tessier No.3 craniofacial cleft: report of three cases and review of literature / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To primarily assess the surgical technique to correct incomplete Tessier No. 3 craniofacial cleft.</p><p><b>METHODS</b>From 2009 to 2010, 3 male patients with incomplete Tessier No. 3 craniofacial clefts were treated. Preoperative CT examination of each patient was performed and the bony defect was evaluated. In the operation, van der Meulen rotation and advancement flap of the cheek and regional Z-plasty were used and the medial canthal ligament was repositioned.</p><p><b>RESULTS</b>One week after the operation, the sutures were removed and the facial incision healed well. The facial scar was not obvious 6 - 10 months after operation. The shape of medial canthal angle was acceptable, and the height of the medial canthal angle and the length of the palpebral fissure of both sides were symmetrical. The clinical results were satisfactory.</p><p><b>CONCLUSIONS</b>For the incomplete Tessier No. 3 craniofacial cleft, surgical treatment is mainly focused on the deformities of inner canthus and nasal alae. Medial canthal ligament reposition is the key procedure for correction of the medial canthal deformity and surgical results are stable and reliable.</p>

Clinical evaluation of computer-navigated surgery in correcting unilateral delayed zygomatic fractures / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To compare the efficacy of computer-navigated surgery and the 3-D skull models and guide plates for the treatment of unilateral delayed zygomatic fractures.</p><p><b>METHODS</b>Eleven patients with unilateral delayed zygomatic fractures were treated by computer-navigated surgery (test group) and another 12 patients were treated by 3-D skull models and guide plates as the control group. Quality of reduction was assessed by examination of postoperative axial CT scans through zygomatic arch, the malar prominence and the width of zygomatic arch were measured in both groups.</p><p><b>RESULTS</b>The difference between bilateral malar prominence was (0.94 ± 0.73) mm in the test group and (1.88 ± 1.82) mm in the control group, there was no significant difference between the two groups (P > 0.05). The difference between bilateral width of zygomatic arch was (0.77 ± 0.51) mm in the test group, less than (3.00 ± 1.81) mm in the control group (P < 0.05). Excessive malar prominence was observed in 6 cases (6/11) in the test group and in 7 cases (7/12) in the control group, whereas malar depression was observed in 5 cases (5/11) in the test group and in 5 cases (5/12) in the control group. Overcorrection of the width of zygomatic arch was observed in 6 cases (6/11) in the test group and in 12 cases (12/12) in the control group, whereas under correction was observed in 5 cases (5/11) in the test group and in 0 cases (0/12) in the control group.</p><p><b>CONCLUSIONS</b>In the treatment of unilateral delayed zygomatic fractures, symmetry of malar prominence can be achieved by application of computer-navigated surgery or the 3-D skull models and guide plates. Symmetry of the width of zygomatic arch achieved with the computer-navigated surgery is better than that achieved with 3-D skull models and guide plates.</p>

Application of computer navigation system in the treatment of post-traumatic reconstruction / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the value of computer aided navigation system (CANS) in the treatment of post traumatic maxillofacial deformation.</p><p><b>METHODS</b>Fifty-four patients (M = 37, F = 17) were included in the study, including 31 cases of zygomatic fracture, 7 cases of pure orbital fracture, 11 cases of temporal mandibular joint ankylosis, 1 case of foreign body and 4 cases of defect reconstruction with custom implant. Data acquisition was done through CT scan, and DICOM data was transferred into workstation. Computer assisted design, including osteotomy, reposition, fibula flap design, orbital implant construction was performed using Surgicase CMF and Brain Lab Iplan system. The virtual design was transferred to Brain Lab navigation system, and the osteotomy, reduction, location of bone graft and custom implant were guided by navigation. Postoperative CT scan was required 48 - 72 hours after surgery. Preoperative and postoperative CT images were superimposed automatically in BrainLab Iplan system, and compared both in 3D objects and 2D slices.</p><p><b>RESULTS</b>All the cases achieved good results without serious complication. The error of important corresponding points in zygomatic fracture reduction, orbital reconstruction and defect reconstruction was 0.2 - 3.5 mm, 0.8 - 2.0 mm and 0.2 - 2.2 mm respectively.</p><p><b>CONCLUSIONS</b>Computer assisted design is of considerable value for the systematic and accurate planning for complicated post traumatic deformation. Virtual plan could be carried out accurately with the assistance of CANS.</p>

Evaluation of the navigation system for orbital wall reconstruction in unilateral orbital fractures / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the efficiency of navigation system for orbital wall reconstruction in unilateral orbital fractures.</p><p><b>METHODS</b>Fifteen patients (7 male and 8 female) with unilateral orbital fracture underwent orbital reconstruction with the help of intraoperative navigation system. The average age was 34.3 ± 9.5 years. All patients underwent spiral CT scanning preoperatively, and the CT data was imported to the BrainLab navigation system (Germany, BrainLab company). The orbit of the intact side was mirrored to the opposite side as the reference for pre-operative planning. The titanium mesh was mounted on the resin template made by rapid prototyping machine based on the mirrored CT data. When the injury was limited, the hydroxyapatite sheet was used for the orbital wall reconstruction. During the operation, the real-time navigation helped to ensure precise placement. The re-establishing result was assessed based on the postoperative CT data with the following four variables: the volumetric difference between the bilateral orbit, the volume of the herniated soft tissue, the global projection and the discrepancy between the simulated and the achieved position of the reconstructed orbital wall. The reconstructive discrepancy was measured only in the titanium plate grafting cases.</p><p><b>RESULTS</b>There were no serious complications such as infection, graft rejection and optic nerve injury in any case. Preoperatively, the average degree of enophthalmos was (3.5 ± 1.6) mm, the average volumetric difference between the injured and the unaffected orbit was (4.5 ± 1.8) ml, and the average volume of the herniated orbital soft tissue was (2.1 ± 0.7) ml. Postoperatively, the three values were respectively reduced to (1.3 ± 0.6) mm, (1.8 ± 0.9) ml and (0.7 ± 0.3) ml. The discrepancy of the medial and inferior wall were (2.5 ± 0.6) mm and (2.1 ± 0.4) mm.</p><p><b>CONCLUSIONS</b>The intraoperative use of navigation system for the orbital wall reconstruction in unilateral orbital fractures can provide reliable accuracy and achieve satisfactory results.</p>

Application of 3-D skull models and guide plates in the treatment of unilateral orbitozygomatic deformity after fracture / 中华整形外科杂志

<p><b>OBJECTIVE</b>To discuss the application of 3-D skull models and guide plates in treatment of unilateral orbitozygomatic deformity after fracture.</p><p><b>METHODS</b>Each patient underwent CT scan and DICOM data was obtained preoperatively. Two 3-D resin skull models were produced by rapid prototyping technique. The first model was produced based on the patient's original data and the second was the reshaped model by mirroring the unaffected facial side to the traumatic side. The original model was used for measurement of the fracture displacement in three directions and model surgery. On the second model, one 2.0 mm miniplate (Synthes Inc) was bended along the orbital rim as the repositioning guide plate. During the operation, osteotomy and reduction of zygomatic and the periorbital fractures was guided by prepared repositioning guide plate, following by orbital wall reconstruction and bone grafting.</p><p><b>RESULTS</b>From March 2007 to February 2009, 7 cases (6 males and 1 female) were treated successfully with no infection or graft extrusion. One week after operation, the patient received CT examination again. The shape and location of zygomatic bone and arch was good. Three cases were followed up for 3 months. Among them, facial symmetry was achieved in 2 cases. Cicatricial contracture and temporal soft tissue atrophy occurred in one case.</p><p><b>CONCLUSIONS</b>Reliable therapeutic effect can be achieved by application of rapid prototyping technique and repositioning guide plate in the treatment of complicated posttraumatic orbitozygomatic deformity.</p>

Measurement of the globe proptosis by CT and its accuracy in patients with unilateral orbital fracture / 中华整形外科杂志

<p><b>OBJECTIVE</b>To evaluate the accuracy of measurement of the globe proptosis by CT in patients with unilateral orbital fracture.</p><p><b>METHODS</b>25 patients with unilateral orbital fracture were included. CT was performed before and after operation. The globe proptosis on the unaffected side was measured before and after operation by using Hertel exophthalmometer (HE), CT images with orbital lateral rim (OLR) and the optic nerve foramen (ONF) as reference points. The accuracy was evaluated comparably by statistical analyses.</p><p><b>RESULTS</b>The preoperative and postoperative average globe proptosis were (13.9 +/- 3.1) mm and (12.5 +/- 2.2) mm in HE group, (16.1 +/- 2.6) mm and (15.7 +/- 2.3) mm in the OLR group, (45.3 +/- 4.8) mm and (46 +/- 3.9) mm in the ONF group, showing a significant difference between the pre-and post-operative results in HE group, but not in OLR and ONF groups.</p><p><b>CONCLUSIONS</b>CT measurement with the orbital lateral rim as reference point is more reliable than Hertel exophthalmometer measurement for globe proptosis.</p>

Prosthetic replacement of condylar head for management of traumatic temporomandibular joint ankylosis / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To preliminarily evaluate the method of using titanium condylar protheses in management of traumatic temporomandibular joint ankylosis.</p><p><b>METHODS</b>Between August 2006 and April 2008, titanium condylar replacement was performed in 5 male patients. Preoperative CT datum of patient was obtained and a resin model was then produced and used as a reference to select a suitable titanium condyle for reconstruction of the joint. In the operation, the bony ankylosis was removed. According to the preoperation planning, the selected prosthesis was inserted and fixed to the distal mandibular segment. The results were assessed by means of examinations and measurements postoperatively and during follow-up.</p><p><b>RESULTS</b>The 5 patients received alloplastic replacement of 6 condyles. Three patients were under follow-up and follow-up time ranged from 8 months to 2 years and 6 months. The mean mouth opening was 30 mm. Two patients had good occlusion and one patient developed a slight open bite.</p><p><b>CONCLUSIONS</b>Prosthetic condylar replacement can provide a choice for management of traumatic temporomandibular joint ankylosis.</p>

Ora-maxillofacial traumatic defects reconstruction with free flaps / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the application, indications and outcomes of free flaps for ora-maxillofacial traumatic defects reconstruction.</p><p><b>METHODS</b>Twenty consecutive cases of ora-maxillofacial the traumatic defects reconstruction with free flaps were reviewed. All clinical data including causes of injuries, the type of defects, selection of free flaps, perioperative complications and the follow-up were analyzed.</p><p><b>RESULTS</b>All the cases underwent free flap reconstruction for ora-maxillofacial traumatic defects: 8 cases with soft tissue defects, 12 cases with soft and hard tissue defects. Fifteen patients received two-stage operation and 5 patients underwent primary reconstruction at the time of debridement or fracture reduction. Twenty free flaps were applied for the reconstruction, 11 cases with fibula flap, 1 case with iliac crest free flap, 7 cases with radial forearm flap and 1 case with scapula flap. No flap failure occurred. The successful rate of free flaps transfer was 100%.</p><p><b>CONCLUSIONS</b>The free flaps transfer is reliable and can reconstruct the ora-maxillofacial traumatic soft and hard tissue defects. Fibula and radial forearm free flap are the most common used flaps. Early aggressive surgery with free flaps transfer for traumatic defects can prevent the scar contracture and tissue displace, which can shorten the treatment period and improve the final outcome.</p>

Volumetric measurement of human orbit by means of computed tomographic analysis based on CT scanning digital data / 中华整形外科杂志

<p><b>OBJECTIVE</b>To establish and elucidate a feasible method by CT-scanning-based computed tomographic analysis for the volumetric measurement of orbit.</p><p><b>METHODS</b>In this study, 19 dry intact dried skulls were used. CT digital data with continuous 0.625 mm transaxial sections was available for each and was inputted a professional tomographic analysis software in DICOM format. Subsequent to the orbital borderline lined on each of continuous axial images, software automatically generated three-dimensional orbital image and gave a value of orbital volume. In mean while, handicraft measurement of orbital volume was carried out for each and obtained another group of orbital volume value. Statistical analysis was made to test possible difference between two measurements.</p><p><b>RESULTS</b>It was demonstrated that volumetric measurement by means of computed tomographic software had a accuracy of the 1.38%. Right and left orbital volumes were found to have a mean difference of 0.3 ml (0-1.4 ml).</p><p><b>CONCLUSIONS</b>CT data-based computed tomographic analysis is a reliable method to measure orbital volume, which could be potentially used to determine the alternation of orbital volume after fracture.</p>

Surgical management of naso-orbital-ethmoid fractures / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To explore the clinical characteristics of naso-orbital-ethmoid (NOE) fracture, principles and surgical methods.</p><p><b>METHODS</b>Twenty-nine patients with NOE fractures were investigated. Operations for the treatment of NOE and subsequent deformities included reduction of central fragment, reconstruction of orbit walls, reattachment of medial canthal ligament and so on. The outcome of the treatment was evaluated.</p><p><b>RESULTS</b>Three cases were infected postoperatively. Of the 14 cases performed on reconstruction of orbit wall, 9 cases got complete correction for their dystopia/enophthalmos, 5 cases improved. Thirteen cases experiencing canthopexy obtained accepted outcome.</p><p><b>CONCLUSIONS</b>The satisfactory correction of NOE fracture and subsequent enophthalmos/dystopia and telecanthus can be achieved with elective surgery in most cases.</p>

Radiological analysis of maxillary sinus density changes after mid-facial fractures / 实用口腔医学杂志

Objective:To evaluate the changes of maxillary sinus density after mid-facial fractures.Methods: A retrospective review was performed on patients with mid-facial fractures from 1995 to 2006.The changes of maxillary sinus density were evaluated by Water's view.Results: There were 219 cases,including 165 male and 54 female patients,who showed changes of maxillary sinus density on Water's view.Their ages ranged from 3 to 78 years.78 cases had follow-up plain radiograph.Among them,51 cases had normal maxillary sinus density,the density of sinuses of 19 cases became lower and the density of sinuses of 8 cases did not change or became higher.Conclusion: The maxillary sinusitis is a late complication and develops in some maxillary sinus after treatment of mid-facial fractures.Attention to the maxillary sinus density should be paied when following-up.