Objective To build up a new contour and functional reconstruction technique of mandibular defects with rapid prototyping and reverse engineering technique. Methods From April 2002 to August 2004, 4 cases of mandibular defects due to resection of large mandible lesion were treated. Of 4 patients, there were 3 females and 1 male, with an age range of 21-42 years, which underwent secondary operation and presented a deviation as mandibular movement. The openingmouth extent was 1.8-2.5 cm(2.2 cm on average). The data of defects area were renewed withMimics and Geomagic Studio software; and the titanium reconstructive frame was designed and manufactured with rapid prototyping technigue. Defect were reconstructed by using CT digital data of patients. Results The CT data could be used by image software directly. The implant design could be completed by computer-aimed design(CAD)/computer-aided manufacture(CAM). The resin model and titanium frame were manufactured accurately by RP technique. Four patients achieved one stage healing. After a follow-up of 3 months to 2 years, largemandibular defect was reconstructed satisfactorily and the opening-mouth extent was 3.03.4 cm(3.2 cm on average). The occluding relation was normal. The implant denture was put on and the mastication function was good in 1 case. Conclusion Individual design and repair of large mandibular defect with CAD/CAM techniques is worth extending application clinically. It is a simple and accurate method.
Objective To examine the mRNA expression of activin A(ACT A) and follistatin(FS) during mandibular lengthening and to elucidate the regulating pattern of during mandibular distractionosteogenesis.Methods Skeletally mature-white New Zealand rabbits were established right mandibular distraction osteogenesis models and the mandibles were lengthened 7 days after osteomy. Atthe end of latency period and the end of distraction period, 10,20, 30, 40 and60 days after fixation, the regenerating tissue of animals’ lengthened mandibles and that of the other side normal mandibles were harvested to extract RNA andto analyse ACT A, FS mRNA by RT-PCR.Results The expression of ACT A mRNA was not detectable in normal bone tissue and ACT A mRNA began to express at the end of latency period. The expression of ACT AmRNA increased gradually along with the beginning of distraction and reached the peak on the 10th and 20th days of distraction which was 5.04 and 4.98 times as much as that of the end of latency period, respectively. The trend of expression of FS mRNA during mandibular distraction osteogenesis was the same as expression of ACT A mRNA. Conclusion ACT A/FS play an important role during rabbit mandibular distraction osteogenesis.
Objective To explore the feasibility and effectiveness of mixed reality technology for localizing perforator vessels in the repair of mandibular defects using free fibular flap. Methods Between June 2020 and June 2023, 12 patients with mandibular defects were repaired with free fibular flap. There were 8 males and 4 females, with an average age of 61 years (range, 35-78 years). There were 9 cases of ameloblastomas and 3 cases of squamous cell carcinomas involving the mandible. The disease duration ranged from 15 days to 2 years (median, 14.2 months). The length of mandibular defects ranged from 5 to 14 cm (mean, 8.5 cm). The area of soft tissue defects ranged from 5 cm×4 cm to 8 cm×6 cm. Preoperative enhanced CT scans of the maxillofacial region and CT angiography of the lower limbs were performed, and the data was used to create three-dimensional models of the mandible and lower limb perforator vessels. During operation, the mixed reality technology was used to overlay the three-dimensional model of perforator vessels onto the body surface for harvesting the free fibular flap. The length of the fibula harvested ranged from 6 to 15 cm, with a mean of 9.5 cm; the size of the flap ranged from 6 cm×5 cm to 10 cm×8 cm. The donor sites were sutured directly in 7 cases and repaired with free skin grafting in 5 cases. Results Thirty perforator vessels were located by mixed reality technology before operation, with an average of 2.5 vessels per case; the distance between the exit point of the perforator vessels located before operation and the actual exit point ranged from 1 to 4 mm, with a mean of 2.8 mm. All fibular flaps survived; 1 case had necrosis at the distal end of flap, which healed after dressing changes. One donor site had infection, which healed after anti-inflammatory dressing changes; the remaining incisions healed by first intention, and the grafts survived smoothly. All patients were followed up 8-36 months (median, 21 months). The repaired facial appearance was satisfactory, with no flap swelling. Among the patients underwent postoperative radiotherapy, 2 patients had normal bone healing and 1 had delayed healing at 6 months. Conclusion In free fibular flap reconstruction of mandibular defects, the use of mixed reality technology for perforator vessel localization can achieve three-dimensional visualization, simplify surgical procedures, and reduce errors.
目的 探讨多层螺旋CT对下颌骨骨折的诊断价值。 方法 对2007年4月-2009年10月下颌骨不同部位骨折的45例患者进行多层螺旋CT轴位扫描，并行多平面、表面遮盖法等三维重建，对下颌骨骨折CT表现特征作回顾性分析。 结果 45例下颌骨骨折中，位于下颌体骨折24例，下颌角骨折5例，下颌升支骨折6例，髁部骨折13例，冠突骨折2例；颞下颌关节脱位中，单侧脱位3例，双侧脱位5例。 结论 多层螺旋CT能准确诊断下颌骨各部位骨折，对诊治方案具有重要价值。
ObjectiveTo investigate the clinical outcomes of resection of mandibular benign tumors and primary reconstruction with autogenous bone graft via an intraoral approach. MethodsFifteen patients with mandibular benign tumors were treated between January 2009 and September 2012. There were 7 males and 8 females, aged from 18 to 45 years (mean, 30 years). The pathological diagnosis identified 11 cases of ameloblastoma, 3 cases of odontogenic keratocyst, and 1 case of odontogenic myxoma. According to the Urken's CRBS (Condyle, Ramus, Body, Symphysis) classification criteria based on the location of the mandibular defect, there were 3 cases of body type (B type), 3 cases of ramus type (R type), and 9 cases of body and ramus type (BR type). The surgeries were performed via an intraoral approach, except 1 patient with the lesion at the level of sigmoid notch via an auxiliary preauricular incision. To fix the bone grafts to the dissected mandibular defects, reconstructive titanium plates were used, either indirectly according to the computer aided design/computer aided manufacturing mandibular models before surgery (9 patients) or directly according to the exposed mandibles during surgery (6 patients). The patients received benign mandibular tumor resection and primary autogenous bone graft reconstruction with free iliac bones (11 cases) or vascularized fibular flaps (4 cases). The mandibular inferior alveolar nerves were preserved in 6 cases. ResultsPrimary healing of incision was obtained in 14 patients, while secondary healing in 1 patient suffering from bone graft infection. All the patients were followed up 1-4 years (mean, 2.5 years). At last follow-up, no patients showed facial nerve damage; occlusion of remaining teeth was similar to preoperative conditions; the chewing function was satisfactory; mouth opening was 30-35 mm (mean, 33 mm); and swallowing and speaking functions were normal. Only slight extraoral scars caused by the auxiliary incision and the transbuccal appliances were observed, and all the patients were satisfied with the facial appearance. Lower lip numbness was relived in patients with preserved inferior alveolar nerves. There was no tumor recurrence during follow-up period. ConclusionThe intraoral approach is a feasible and proper approach for resection of benign mandibular tumors and primary reconstruction with autogenous bone grafts, with the advantages of inconspicuous facial scars, minimum damage to the facial nerve, and expectable aesthetic appearance.
Simultaneous restoration of function and appearance should be performed in mandibular reconstruction. Option of reconstructive techniques is determined by cause, location, extent, and classification of the mandibular defects. Vascularize bone graft is one of the most popular technique in current clinical practice of mandibular reconstruction. Fibula is the most common donor site for mandibular reconstruction. The disadvantage of low height of neo-mandible reconstructed by single fibular segment can be solved by vascularized double barrel fibula graft. Using virtual surgical planning and intraoperative navigation for mandibular reconstruction leads to simplify surgical procedure, reduce operating time and injury, and decrease donor site morbidity so that accurate mandibular reconstruction could be completed. Direction of minimal invasive surgery for mandibular reconstruction will be developed by intraoral approach and intraoral anastomosis.
Objective To investigate the mode and influential factor of newbone formation following distraction osteogenesis in mandibular lengthening. Methods Corticotomy was performed on bilateral mandibles in twelve adult male goats. A custommade distractor was used to lengthen the mandible at a rate of 1mm/day for 10 days (total 10 mm elongation). Four goats were sampled respectivelyat 2, 4 and 8 weeks after completion of distraction. The lengthening mandibles were examined by roentgenography and histology. Results Newly formed callus was observed in the distraction gap after mandibular lengthening. The new bone exhibited intramembranous ossification generally, but cartilage islands could be found in the specimen that diastractor loosed. Conclusion The above findings indicate that the mode of new bone formation in mandibular lengthening following distraction osteogenesis appears to be intramembranous ossification and that endochondral ossification takes place in case distractor has loosened.
【Abstract】 Objective To evaluate the effect on repairing composite defect of mandible and skin by pre fabricatedmusculocutaneous flap including ectopic bone induced by BMP-2 and collagen in rabbits’ latissimus dorsimuscle. Meth ods Twenty-four rabbits (4-6 weeks old) were randomly divided into 3 groups: experimental, control and blank control group (n=8 in each group). Composite carriers composed of BMP-2 and collagen I sponge were implanted into latissimus dorsi muscle pouches of rabbits. The bone formation was evaluated with roentgenography, ALP staining, Von Kossa staining, HE staining, toluidine blue staining and CD31 immunohistochemical labell ing of microvessels. After 6 weeks, the mandibular defect of 8 mm in diameter with local skin defect of 2 cm × 3 cm was made in experimental group, and a musculocutaneous flap including ectopic-induced bone was prefabricated to transfer and repair the composite defect. The mandibular defect of 8 mm in diameter without local skin defect was made in control and blank control group. Free ectopic-induced bone was used for the repair of mandibular defect in control group, but repairing was not performed in blank control group. All the samples were detected 6 weeks after operation for tetracycl ine fluorescent staining, X-ray, histological examination and bone quantity analysis to evaluate the effect. Results Bone formation induced by BMP-2/collagen composites were found as woven bone between 4 to 6 weeks. It showed that cartilaginous osteogenesis was the mainly type of bone formation. Microvessels could beseen in the bony tissues. The composite defects of mandible and skin were healed well in the experimental group. Major bony tissue were seen in the control group, while it still remained bony defect in the blank control group. The bone quantity analysis in the experimental, control, and blank control group were (1.594 ± 0.674), (0.801 ± 0.036), and (0.079 ± 0.010) mm2, there were significant differences between each groups (P lt; 0.05). Conclusion Prefabrication of musculocutaneous flap including boneinduced by the composite of BMP-2 and collagen is feasible and prevalent. It can be regarded as vascularized bone graft and used in repairing composite defect of bone and skin.
OBJECTIVE: To establish the animal models of mandibular distraction osteogenesis in rabbits and study its osteogenetic mechanism. METHODS: The right mandibles just anterior to the first molars of 12 rabbits were performed osteotomies, and the mandibles were positioned with distractors. The left mandibles were control group without operation. After 1 week, the distractors were stretched 0.9 mm every day for 10 days progressively. One day, 2, 4, 8 weeks after distraction, the mandibles were studied with gross measurement, X-ray, and histological examination. RESULTS: The right mandible were lengthened 8.3 mm on average without bone nonunion and deformity healing. It was observed that the gaps between the distracted bone edges were first occupied by fibrous tissue. Two weeks after distraction, it was found that the gaps were bridged by callus in X-ray, the new bone and the normal bone could not be differentiated clearly after 8 weeks. In histological sections, there were collagen bundles in early distraction, then those collagen bundles were calcificated and become trabeculaes. No Cartilage was found during distraction. CONCLUSION: It suggests that the rabbit mandible can be lengthened by distraction osteogenesis, and the new bone is formed by intramembranous ossification.
Objective To evaluate the directional significance of SurgiCase software in free fibula mandibular reconstruction. Methods Between September 2010 and March 2012, 10 patients with mandibular defect underwent free fibula mandibular reconstruction. There were 7 males and 3 females, with an age range of 19-43 years (mean, 27 years). The extent of lesions was 7 cm × 5 cm to 16 cm × 8 cm. In each case, three-dimensional spiral CT scan of the maxilla, mandible, and fibula was obtained before surgery. The CT data were imported into the SurgiCase software and the virtual surgery planning was performed. After that, the mandibular rapid prototyping was made according to customized design. The reconstruction surgery was then carried out using these preoperative data. During actual surgery, the extent of mandibular defect was from 6 cm × 3 cm to 16 cm × 5 cm; the length of fibula which was used to reconstruct mandible was 6-17 cm; and the area of flap was from 6 cm × 5 cm to 16 cm × 6 cm. Results Preoperative data could not be applied because the intraoperative size of tumor was larger than preoperative design in 1 case of mandibular ameloblastoma, and the fibula was shaped according to the actual osteotomy location; operations were performed successfully according to preoperative design in the other 9 patients. The operation time was 5-7 hours (mean, 6 hours). Primary healing of incision was obtained, without early complications. Ten patients were followed up 1 year. At last follow-up, 8 patients were satisfactory with the appearance and 2 patients complained with unsatisfied wide facial pattern. The panoramic radiograghs showed good bone healing. The range of mouth opening was 2.5-3.5 cm. Conclusion SurgiCase software can provide precise data for free fibula mandibular reconstruction during surgery. It can be applied widely in clinic.