Recurrence-Related Factors of Temporomandibular Joint Ankylosis: A 10-Year Experience.

PURPOSE: The treatment of temporomandibular joint (TMJ) ankylosis can be challenging for surgeons because of technical difficulties and a high incidence of recurrence. In the present study, we reviewed the data from patients with TMJ ankylosis during a 10-year period and explored the risk factors for recurrence. MATERIALS AND METHODS: A retrospective cohort study was conducted to review the data from patients with TMJ ankylosis from January 1, 2006 to December 31, 2015. The predictor variables were age, TMJ ankylosis classification, and treatment method. The primary outcome variable was the recurrence rate of TMJ ankylosis during follow-up. The χ2 test or Fisher exact test was performed to analyze the differences in the recurrence rate. RESULTS: A total of 130 patients (59 females and 71 males; age, 3 to 67 years) were included in the present study. All the patients were divided into 3 groups according to their age. The rate of joint reankylosis among the children was 19.1%, which was significantly greater than that of the adults (7.3%; P < .05). In the adults, the joint was reconstructed using a coronoid process graft (CPG), distraction osteogenesis, or prosthesis implantation for type III. Among these treatments, CPG resulted in the greatest recurrence rate (26.7%). CONCLUSIONS: Children with ankylosis were found to be more prone to recurrence compared with adults. TMJ ankylosis was also more likely to recur in adults undergoing reconstruction with a CPG.

Width-Controlling Fixation of Symphyseal/Parasymphyseal Fractures Associated With Bilateral Condylar Fractures With 2 2.0-mm Miniplates: A Retrospective Investigation of 45 Cases.

PURPOSE: Symphyseal and parasymphyseal fractures and bilateral condylar fractures represent a pattern that is quite challenging to manage. This study evaluated the treatment outcomes of a group of patients who underwent surgery using miniplate fixation for anterior mandibular fractures. MATERIALS AND METHODS: This retrospective case series study reviewed patients with bilateral condylar fractures and noncomminuted symphyseal and parasymphyseal fractures. The patients were surgically treated from 2008 to 2014 in the department of oral surgery. Evaluation of facial width control was considered the primary outcome variable, which consisted of clinical assessment and measurement of the lingual gap using computed tomography. Medical information was collected before surgery. Temporomandibular joint function and postoperative complications also were evaluated during follow-up. A paired sample t test was used for statistical analysis. RESULTS: Forty-five patients (37 male, 8 female; mean age, 34.8 ± 14.5 yr; range, 16 to 74 yr) were included in this study. Lingual gaps measured before surgery (3.38 ± 0.61 mm) and after surgery (0.64 ± 0.14 mm) were significantly different (P < .001). No patient was rated as "unsatisfactory" after esthetic evaluation of facial width. CONCLUSION: For noncomminuted symphyseal and parasymphyseal fractures associated with bilateral condylar fractures, 2 2.0-mm miniplates with monocortical screws are stable and efficacious in controlling mandibular width when bilateral condylar fractures are anatomically reduced and stably fixated.

Comparative study of four maxillofacial trauma scoring systems and expert score.

PURPOSE: To select a scoring system suitable for the scoring of maxillofacial trauma by comparing 4 commonly used scoring systems according to expert scoring. PATIENTS AND METHODS: Twenty-eight subjects who had experienced maxillofacial trauma constituted the study cohort. Four commonly used systems were selected: New Injury Severity Score (NISS), Facial Injury Severity Scale (FISS), Maxillofacial Injury Severity Score (MFISS), and Maxillofacial Injury Severity Score (MISS). Each patient was graded using these 4 systems. From the experience of our trauma center, an expert scoring table was created. After the purpose and scheme of the study had been explained, 35 experts in maxillofacial surgery were invited to grade the injury of the 28 patients using the expert scoring table according to their clinical experience. The results of the 4 scoring systems and expert score were compared. RESULTS: The results of the 4 scoring systems and expert score demonstrated a normal distribution. All results demonstrated significant differences (P < .01). The Pearson correlation coefficient between the MFISS and expert score was the greatest (0.801). The correlation coefficient between the NISS, FISS, and MISS and the expert score was 0.714, 0.699, and 0.729, respectively. Agreement between the standardized scores and the expert score was evaluated using Bland-Altman plots; the agreement between the standardized MFISS and expert score was the best. CONCLUSIONS: Compared with the other 3 scoring systems, the correlation and agreement between the MFISS and expert score was greater. This finding suggests that the MFISS is more suitable for scoring maxillofacial injuries.

Quantitation of zygomatic complex symmetry using 3-dimensional computed tomography.

PURPOSE: To improve the clinical evaluation of the symmetry of the zygomatic complex (ZMC), the authors developed a new method to measure the eminence and width of the ZMC using 3-dimensional (3D) computed tomography (CT). The accuracy and reproducibility of the ZMC symmetry evaluation using this method were investigated. MATERIALS AND METHODS: Spiral CT was carried out in 50 volunteers with visually symmetric faces. Based on an exact craniofacial midsagittal plane, a 3D coordinate system was constructed and used to measure the eminence and width of the ZMC. Absolute differences between the bilateral eminences and widths were calculated as ΔE and ΔW, respectively. The ZMC eminence also was measured based on traditional methods using anatomic landmarks, and the bilateral absolute difference was calculated to serve as a control (ΔcE). RESULTS: The ΔE value was lower than the ΔcE value (0.6 vs 1.75 mm; P < .001). None of the results for ΔE were larger than 2 mm, and 7 results (3.5%) for ΔW were larger than 2 mm. By comparison, 57 results (28.5%) for ΔcE were larger than 2 cm (P < .001). The intraclass correlation coefficient (ICC) indicated almost perfect agreement for inter- and intraexaminer reliabilities for ΔE (ICC, 0.82 to 0.86) and ΔW (ICC, 0.81 to 0.85) measurements, and moderate agreement for inter- and intraexaminer reliabilities was obtained for ΔcE (ICC, 0.61 to 0.68) measurements. CONCLUSION: This new method is practical and valuable in the clinical evaluation of ZMC symmetry.

Quality of life of patients with neurodermatitis.

BACKGROUND: Neurodermatitis is a common chronic skin disease. Although not life-threatening, it can produce an important psychosocial burden, sleep disturbance and sexual dysfunction. Patients with neurodermatitis tend to have poor social skills or interpersonal resources and a lack of flexibility. However quality of life (QoL) of patients with neurodermatitis has seldom investigated. The objective of this study is to assess the impact of neurodermatitis on patients' QoL using the Dermatology Life Quality Index questionnaire, and assess its feasibility and internal consistency. METHODS: One hundred and fifty consecutive outpatients seeking treatment for neurodermatitis and 250 patients with psoriasis in the Department of Dermatology, the Second Hospital of Xi'an Jiaotong University, were assessed for eligibility for this prospective study from July 1, 2011 to September 30, 2011. Demographic data and disease-related characteristics were collected. RESULTS: The overall mean DLQI score for neurodermatits (9.34) was lower than that for psoriasis (13.32) (P < 0.001). Patients with neurodermatitis scored significantly lower for all items except Q1 (symptoms) and Q9 (sexual difficulties). No strong relationship between disease-related characteristics and quality of life could be found. The inter-item correlation averaged 0.415 and Cronbach's alpha was 0.889, indicating high internal consistency. CONCLUSION: This is the first study to attempt to measure the impact of neurodermatitis for both male and female patients on QoL. Neurodermatitis moderately affected the QoL of the patients.

Zygomatic surface marker-assisted surgical navigation: a new computer-assisted navigation method for accurate treatment of delayed zygomatic fractures.

PURPOSE: To describe a new method of zygomatic surface marker navigation to treat delayed unilateral zygomatic fractures. PATIENTS AND METHODS: The computed tomography (CT) data for 6 patients were obtained before surgery and imported into the surgical planning software. After 3-dimensional (3D) construction and segmentation, 3D cylindrical-shaped objects in stereolithographic format were placed in position and merged with the data from the fractured segments to mark the area for surface reduction. Data from the unaffected side were used to guide the reduction data for the segments with markers. During surgery, the surface markers were marked by drilling holes in the fractured bones in a process guided by the surgical navigation plan established before osteotomy. The segments were then reduced to the predetermined places using the positions of the hole markers as guides. 3D image comparisons and axial CT measurements were used to evaluate navigation accuracy and bone symmetry. RESULTS: Six patients with unilateral delayed zygomatic fractures were treated using this approach. The mean deviation between the postoperative 3D images and the reduction navigation plan for the 6 patients was +1.24 mm and -1.4 mm. The mean width deviation between the affected and unaffected sides was 1.28 mm, and the mean eminence deviation was 1.22 mm. All patients were followed up for at least 3 months and experienced no obvious complications. CONCLUSIONS: Zygomatic surface marker-assisted surgical navigation can simplify the navigation planning for surgery and avoid the complex protocols needed to create the surgical templates. The navigation accuracy was acceptable, and all 6 patients obtained good facial symmetry.

Correlation of types of orbital fracture and occurrence of enophthalmos.

We sought to investigate the correlation between type of orbital fracture and occurrence of traumatic enophthalmos. The 119 patients with orbital fractures were divided into the enophthalmos group (71 cases) and the nonenophthalmos group (48 cases). The 2 groups were compared by location and type of orbital fracture based on observation of computed tomography scans. We found the incidence of medial wall fractures significantly higher in the enophthalmos group (76.06%) than in the nonenophthalmos group (22.92%, χ(2) = 32.63, P < 0.05). The incidence of combined medial-inferior wall fractures was also significantly higher in the enophthalmos group (52.93%) than in the nonenophthalmos group (12.5%, χ(2) = 23.21, P < 0.05). However, the incidence of lateral-inferior wall fractures was significantly lower in the enophthalmos group (36.62%) than in the other group (58.33%, χ(2) = 4.11, P < 0.05). In most cases of lateral-inferior orbital wall fracture in the enophthalmos group, the zygomatic complex was displaced toward the lateral-posterior direction. The combined medial-inferior wall fracture is likely the primary type of multiple wall fracture leading to traumatic enophthalmos. Enophthalmos caused by a combined lateral-inferior fracture may be correlated with lateral-posterior displacement of the zygomatic complex.

[Anatomic study and preliminary clinical application of the laterally based pericranial flap to treat traumatic enophthalmos].

OBJECTIVE: To assess the vascularization of the laterally based pericranial flap and the feasibility of bony channel on the orbital lateral wall for transplantation of the flap, and apply this flap to treat traumatic enophthalmos. METHODS: Two formalin preserved cadaver specimens were anatomized to observe the feasibility of pericranial flap transplantation through the bony channels on lateral orbital walls. Two fresh cadaver specimens were perfused with latex and ink respectively to observe the possible blood supply to laterally based pericranial flaps. Two patients with unilateral old orbital fracture were treated using this flap. The enophthalmos degrees were measured before and after operation to evaluate the effect of this therapy. RESULTS: It was feasible to transplant the pericranial flap into orbit through the bony channel on lateral orbital wall, reaching the medial wall and orbital floor. Vascular perfusion did not reveal that the laterally based pericranial flap over the supra temporal line was vascularized by any axial vessel. The ink perfusion of one side showed that the middle temporal artery extended deeply under the deep temporal fascia, but didn't cross the supra temporal line. The subgaleal vascular plexus was observed obviously in the superficial layer of pericranial flap. The enophthalmos degrees of the two patients were respectively 5.35 mm and 6.86 mm prior to operation. They both showed desirable outcomes postoperation (<2 mm). CONCLUSION: It is feasible to transfer the laterally based pericranial flap into orbit through the lateral orbital wall channel. The laterally based pericranial flap is possibly vascularized by the subgaleal vascular plexus. The primary treatment of traumatic enophthalmos using the laterally based pericranial flap is satisfactory.

Evaluation of the application of computer-aided shape-adapted fabricated titanium mesh for mirroring-reconstructing orbital walls in cases of late post-traumatic enophthalmos.

PURPOSE: Computer-aided individually shape-adapted fabricated titanium mesh for the mirroring-reconstruction of the orbit is a promising method for the correction of post-traumatic enophthalmos. The purpose of this study was to evaluate the application of this technique and assess the treatment outcomes. PATIENTS AND METHODS: Twenty-one patients with delayed treatment of unilateral impure orbital fracture and post-traumatic enophthalmos were included in this study. Computed tomography-based mirroring-reconstruction images of the orbit were obtained for each individual to fabricate anatomically adaptive titanium mesh by computer-aided design and computer-aided manufacturing techniques. After exposing the areas of orbital defect and reducing the herniated soft tissue, the titanium mesh was inserted to reconstruct the internal orbit with a mean deep extension of 29.33 mm. Measurements were performed to assess the change in the degree of enophthalmos and orbital volume before and after surgery. Paired samples t test and Pearson correlation coefficient were employed for statistical analysis. RESULTS: Follow-up examinations revealed that the degree of enophthalmos decreased to less than 2 mm in 11 patients, 2 to 4 mm in 9 patients, and remained greater than 7 mm in 1 patient. Statistical analysis revealed that post-traumatic enophthalmos in this series was 4.05 +/- 2.02 mm, which was associated with an orbital volume increment of 6.61 +/- 3.63 cm(3), with a regression formula of enophthalmos = 0.446 x orbital volume increment + 2.406. Orbital reconstruction effected a orbital volume decrease of 4.24 +/- 2.41 cm(3) and enophthalmos correction of 2.01 +/- 1.46 mm, the regression formula being enophthalmos = 0.586 x orbital volume decrease + 0.508. After surgery, the degree of unresolved enophthalmos was 2.03 +/- 1.52 mm, and the retained orbital volume expansion was 2.23 +/- 2.86 cm(3), and the regression formula was enophthalmos = 0.494 x orbital volume expansion + 1.415. CONCLUSION: Application of the individual fabricated titanium mesh for orbital reconstruction reduced the trauma-induced orbital volume increment by 65% and corrected 50% of severe late enophthalmos. Additional augmentation of orbital contents was required for further correction. The related treatment parameters were suggested.

[Computer-assisted fabricated individual titanium mesh for reconstruction of orbital wall].

OBJECTIVE: The aim of this study was to develop and assess the computer-assisted fabricated individual titanium mesh technique applied for reconstruction of fractured orbital walls to correct post-traumatic enophthalmus and diplopia. METHODS: Twenty patients (12 males and 8 females) were included in this study. All of patients suffered from unilateral impure orbital fractures. Group A included 8 patients who were reconstructed for the fractured orbit with computer-assisted fabricated titanium mesh technique. Group B had 12 patients treated with traditional methods (titanium meshes in 2, autogenous bone grafts in 7 and Medpor implantation in 3). CT data of group A was input into a image software to rebuild a 3-D orbit and then mirror the unaffected side onto the affected side to replace the demolished orbit. A resin model of the reshaped orbit was then produced and was used to develop custom-fabricated titanium mesh for repair of the fractured orbital wall. The fabricated mesh was used in operation to reconstruct the orbital wall. Treatment was assessed in comparison with traditional way by means of clinical examinations and CT measurements. RESULTS: The difference between pre-operative and post-operative enophthalmos: the mean value of group A was 2.6 mm, group B was 2.0 mm;the difference between the pre-operative and post-operative enlargement volume of traumatic orbit: the mean value of group A was 4.3 mL, group B was 3.7 mL; Index of Medial orbital wall of both groups was 100% and Index of inferior wall reconstruction of group A was 84.7%, group B was 53.3%; The mean depth of implants of group A was 31.2 mm, of group B was 28.3 mm; Improvement of diplopia of group A was 1.5 quadrants, that of group B was 1 quadrant. There were no infection, gaze restriction, or graft extrusion in all patients after operation. CONCLUSION: Computer-assisted fabricated titanium mesh technique could provide more accurate orbital reconstruction and improve the correction of enophthalmus and diplopia.

One-stage technique for sagittal split ramus osteotomy combined with mandibular angle ostectomy.

Bilateral sagittal split ramus osteotomy (BSSRO) is commonly used to correct mandibular prognathism or retrognathism. Patients with mandibular prognathism or retrognathism may also present with a prominent mandibular angle. In this paper, we share our experience on BSSRO with mandibular angle resection. Eleven patients who were treated from July 2014 to December 2016 were included in this study. The mandibular angle was resected through the medial side of the mandible after BSSRO. The mandibular angle measurements of the patients changed significantly after surgery (p < 0.05). Unanticipated fractures and mandibular hematoma did not occur. Therefore, BSSRO combined with mandibular angle ostectomy through the medial side of the mandible can be used to safely and effectively correct facial deformity.

A pilot trial on the molecular pathophysiology of traumatic temporomandibular joint bony ankylosis in a sheep model. Part I: Expression of Wnt signaling.

OBJECTIVE: To preliminarily investigate the temporal patterns of the endogenous mRNA expression for members of the Wnt signaling and a series of genes regulating bone formation during the development of traumatic temporomandibular joint (TMJ) bony ankylosis in a sheep model. METHODS: Six sheep were used for the induction of bony ankylosis of TMJ. We performed a condylar fracture, excision of the lateral 2/3 disc and serious injury to the glenoid fossa to induce bony ankylosis on the right TMJ. An isolated condylar fracture was performed on the left side. Two sheep were sacrificed at 1 month, 3 months, and 6 months after surgery, respectively. The specimens from the ankylosed joint and the condylar fracture were harvested for RNA extraction respectively. In this report (Part I), only the bony ankylosed samples were used for analysis of gene expressions. The specimens 1 month postoperatively were taken as the control, and the changes of expression of target genes over time were examined by real-time PCR. RESULTS: mRNA expression of Wnt1, Wnt2b, Wnt3a, ß-catenin, Sfrp1, Lrp6, Lef1, CyclinD1, and Runx2 was up-regulated at 3 and 6 months compared with 1 month. The expression of Wnt5a, Sox9, and Osterix was up-regulated with a peak at 3 months, and then fell back to the basal levels at 6 months. The expression of Ocn began to up-regulate until 6 month postoperatively. CONCLUSION: Our findings suggested that Wnt signaling was involved in the formation of traumatic TMJ bony ankylosis and thus may be a potential therapeutic target for the treatment of the disease in the future.

A pilot trial on the molecular pathophysiology of traumatic temporomandibular joint bony ankylosis in a sheep model. Part II: The differential gene expression among fibrous ankylosis, bony ankylosis and condylar fracture.

OBJECTIVE: The purpose of the study was to preliminarily explore the differential expressions of a series of genes regulating bone formation in temporomandibular joint (TMJ) fibrous ankylosis, bony ankylosis and condylar fracture healing. METHODS: The cDNA from either the bony ankylosed callus or fracture callus of the 6 sheep, as described in the part I, were both used in the study. The differences of gene expressions between bony ankylosis and condylar fracture at 1, 3, and 6 months postoperatively were measured by real-time PCR, with 2 samples at each time point. In addition, another 2 sheep were added to have fibrous ankylosis induced on the right TMJ, and 1 sheep was sacrificed at 3 and 6 months after surgery, respectively. The differences of gene expressions between fibrous and bony ankylosis at 3 and 6 months postoperatively were measured by real-time PCR. RESULTS: Bony ankylosis showed higher mRNA expression trends in Wnt2b, Wnt5a, ß-Catenin, Lef1, CyclinD1, Runx2, Osterix, Sox9, Col10a1, Alp, Ocn, Bmp2, and Bmp7 compared to fibrous ankylosis, although no statistical analysis was performed due to the very small sample size. Whereas bony ankylosis showed a significant lower expression of Wnt5a, ß-Catenin, Lef1, Runx2, Osterix, Sox9, Col10a1, Alp, Ocn and Bmp4 compared to condylar fracture at several time points (P < 0.05). CONCLUSION: Our data provided a preliminary molecular evidence for the hypothesis that the development of traumatic TMJ bony ankylosis was the course of delayed bone healing or hypertrophic nonunion, and deserved to be further studied.

Imaging and histologic features of traumatic temporomandibular joint ankylosis.

OBJECTIVE: We aimed to study the pathology underlying traumatic temporomandibular joint ankylosis (TMJA). STUDY DESIGN: Specimens from 10 patients with traumatic TMJA were categorized using the Sawhney classification and were decalcified and stained with hematoxylin-eosin, alcian blue/periodic acid-Schiff, alizarin red, and Masson stains. Immunostaining with anti-CD34 antibody was performed. Computed tomography and pathologic findings were compared. RESULTS: Ankylosed areas consisted of fibrocartilaginous tissues. Bone formation occurred by osteophyte extension from the osteochondral surface toward the mass center. Endochondral ossification and osteophyte proliferation, alone or simultaneously, participated in bony ankylosis. Sequestra in the cartilaginous ankylosis preferentially formed bony bridges. Newly formed capillaries participated in ossification from the bony surface of the bone-cartilage junction; bone formed around the capillaries. Osteoclasts were present at the capillary tips. CONCLUSIONS: Types II and III were cartilaginous-bony ankylosis, with similar components. Bony traumatic TMJA was formed by osteophyte proliferation and endochondral ossification.

Surgical induction of TMJ bony ankylosis in growing sheep and the role of injury severity of the glenoid fossa on the development of bony ankylosis.

OBJECTIVE: The purpose of this paper is to summarize our experiences in creating an animal model of TMJ bony ankylosis based on 2 sequential experiments. METHODS: Two sequential experiments were performed with the aim of creating a model of TMJ bony ankylosis. Seven growing sheep were used in the first experiment, in which 1 was served as a control animal. Condylar fracture with disc preservation was performed on the control side. On the contralateral side, condylar fracture, excision of the lateral 2/3 disc and injury to the glenoid fossa were performed to induce bony ankylosis. Three animals were sacrificed respectively at 3 and 6 months after surgery. In the second experiment, 7 growing sheep were used. The only difference of modeling between the 2 experiments was that more serious injury to the glenoid fossa was made in the ankylosis-induced side in experiment 2. Three, 2, and 2 animals were sacrificed respectively at 1, 3, and 6 months postoperatively. The TMJ complexes were examined by computed tomography (CT) and histological evaluation. RESULTS: In experiment 1, only fibrous ankylosis was observed in the ankylosis-induced side both at 3 and 6 months postoperatively. In experiment 2, CT and histological evaluation showed that the outcomes of the ankylosis-induced side were fibrous-bony ankylosis, fibrous-bony ankylosis, and bony ankylosis respectively at 1, 3, and 6 months after surgery. CONCLUSION: Through summarizing the differences of the modeling and the different outcomes in the 2 experiments, we concluded that severe damage to the glenoid fossa played an important role in the development of TMJ bony ankylosis.

Ankylosing spondylitis associated with bilateral ankylosis of the temporomandibular joint.

OBJECTIVE: The objective of this study was to analyze the clinical and laboratory features, treatments, and prognosis of ankylosing spondylitis (AS) associated with bilateral temporomandibular joint ankylosis (TMJA). METHODS: A PubMed search was conducted from 1966 to date, and the references of published studies were also checked to identify additional cases. Information from these reports and our report were compared and analyzed. RESULTS: Published literature in the past 36 years, which included 8 cases, were reviewed. The mean (SD) age at diagnosis of AS and bilateral TMJA was 21.00 (6.35) and 32.50 (13.43) years, respectively. Ankylosis of cervical vertebra was described in all patients. Total alloplastic joints and artificial condyle replacements were also reported in recent years. The slices of ankylotic mass showed the marrow was infiltrated by eosinophilic granulocytes. CONCLUSION: Evaluating temporomandibular joint (TMJ) function is strongly recommended in patients who have a long history of AS, particularly in cases involving cervical vertebrae disease.

[Surgical treatment for incomplete Tessier No.3 craniofacial cleft: report of three cases and review of literature].

OBJECTIVE: To primarily assess the surgical technique to correct incomplete Tessier No. 3 craniofacial cleft. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

[Clinical evaluation of computer-navigated surgery in correcting unilateral delayed zygomatic fractures].

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

[Application of computer navigation system in the treatment of post-traumatic reconstruction].

OBJECTIVE: To investigate the value of computer aided navigation system (CANS) in the treatment of post traumatic maxillofacial deformation. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

[Evaluation of the navigation system for orbital wall reconstruction in unilateral orbital fractures].

OBJECTIVE: To evaluate the efficiency of navigation system for orbital wall reconstruction in unilateral orbital fractures. METHODS: 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. RESULTS: 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. CONCLUSIONS: The intraoperative use of navigation system for the orbital wall reconstruction in unilateral orbital fractures can provide reliable accuracy and achieve satisfactory results.