[An experimental study on segmental defects reconstruction of canine mandible with allogenic bone marrow mesenchymal stem cells combined with lyophilized bone].

OBJECTIVE: To investigate the effect of segmental defects reconstruction of canine mandible with allogenenic bone marrow mesenchymal stem cells (BMSC) combined with lyophilized bone. METHODS: A 30 mm segmental defect was created on the left mandibles of beagles. Beagles were randomly divided into three groups. Allogeneic bone marrow mesenchymal stem cells with lyophilized bone were used for segmental defects reconstruction in group A. Autologous bone marrow mesenchymal stem cells with freeze- dried bone were used for segmental defects reconstruction in group B. The defects of group C were repaired with lyophilized bone only. Every three beagles were sacrificed 4, 12, 24, and 48 weeks after surgery respectively. The reconstruction effect was evaluated by CT and histopathological examination. RESULTS: CT examination showed that new bones formed in group A and group B 12 weeks after surgery, but not in group C. The form of the reconstructed mandibles in the three groups recovered in 48 weeks. The small pores on the bone graft were filled with new bones in group A and group B. In group C, the pores were still evident. Histopathological examination showed that bone trabecula between allogeneic bone and autogenous bone was completely joined in group A and group B. A large number of fibrous tissue appeared around the implanted bone and new bones were formed. In group C, the lyophilized bone resorption was still not obvious, the new bone formation was significantly slower than the other two groups. There was no difference between group A and group B. CONCLUSIONS: Both allogeneic bone marrow mesenchymal stem cells and autologous mesenchymal stem cells could accelerate the bone formation.

Reconstruction of beagle hemi-mandibular defects with allogenic mandibular scaffolds and autologous mesenchymal stem cells.

OBJECTIVE: Massive bone allografts are frequently used in orthopedic reconstructive surgery, but carry a high failure rate of approximately 25%. We tested whether treatment of graft with mesenchymal stem cells (MSCs) can increase the integration of massive allografts (hemi-mandible) in a large animal model. METHODS: Thirty beagle dogs received surgical left-sided hemi-mandibular defects, and then divided into two equal groups. Bony defects of the control group were reconstructed using allografts only. Those of the experimental group were reconstructed using allogenic mandibular scaffold-loaded autologous MSCs. Beagles from each group were killed at 4 (n = 4), 12 (n = 4), 24 (n = 4) or 48 weeks (n = 3) postoperatively. CT and micro-CT scans, histological analyses and the bone mineral density (BMD) of transplants were used to evaluate defect reconstruction outcomes. RESULTS: Gross and CT examinations showed that the autologous bone grafts had healed in both groups. At 48 weeks, the allogenic mandibular scaffolds of the experimental group had been completely replaced by new bone, which has a smaller surface area to that of the original allogenic scaffold, whereas the scaffold in control dogs remained the same size as the original allogenic scaffold throughout. At 12 weeks, the BMD of the experimental group was significantly higher than the control group (p<0.05), and all micro-architectural parameters were significantly different between groups (p<0.05). Histological analyses showed almost all transplanted allogeneic bone was replaced by new bone, principally fibrous ossification, in the experimental group, which differed from the control group where little new bone formed. CONCLUSIONS: Our study demonstrated the feasibility of MSC-loaded allogenic mandibular scaffolds for the reconstruction of hemi-mandibular defects. Further studies are needed to test whether these results can be surpassed by the use of allogenic mandibular scaffolds loaded with a combination of MSCs and osteoinductive growth factors.

[Application of computer-aided surgery in fibrous dysplasia of cranio-maxillofacial bone].

PURPOSE: To evaluate the effect of computer-aided surgical techniques in surgical treatment of cranio-maxillofacial fibrous dysplasia. METHODS: Twenty-two patients from January 1999 to December 2012 with cranio-maxillofacial fibrous dysplasia were treated in our department. According to the patients' specific conditions, surgeons designed surgical programs, and used computer-assisted surgical techniques to produce skull model and navigation template individually. The effects after surgery were evaluated. RESULTS: Twenty-two patients with resection of the bone lesions restored facial symmetry partially. The patients were followed up for 3 to 36 months, and the treatment effects were satisfactory. CONCLUSIONS: With preoperative planning, intraoperative navigation and postoperative prediction, computer-aided surgery shows its great value in improving the accuracy of cranio-maxillofacial surgery, shortening operating time and restoring facial symmetry. It is regarded as a valuable and safe surgical technique in cranio-maxillofacial surgery. Supported by Beijing Natural Science Foundation (7112124).

[Early reconstruction of the periorbital injuries].

OBJECTIVE: To study the clinical characteristics and the treatment of periorbital injuries. METHODS: 61 cases were treated, including 30 cases orbitozygomatic fracture, 6 cases of frontal-orbital fracture, 8 cases of naso-ethmoid-orbital fracture, 7 cases of blow -out fracture and 10 cases of complicated fracture. The patients were diagnosed after physical examination and other examination, like CT. Through bicoronal or local mini incision at the end of eyebrow, combined with subciliary incision and local wound approach, the fractured sites were exposed completely. Then the fractured fragments were repositioned and fixed rigidly. The orbital wall was reconstructed with titanium net and Medpor. RESULTS: The wounds healed primarily. Good cosmetic and functional results achieved in most of the patients. 4 cases underwent second-stage ophthalmectomy. 2 patients had diplopia after operation, but improved gradually. 3 cases of blepharoptosis needed further treatment. CONCLUSIONS: Early diagnosis and treatment is very important for periorbital injuries. Fracture reposition and orbital wall reconstruction should he performed at early period.

[Genioplasty with two-step osteotomy for severe microgenia].

OBJECTIVE: To investigate a technique for correction of severe microgenia. METHODS: The mandibular symphysis was exposed through intraoral mucous incision. Two parallel osteotomies were performed under mental foramen. The mobilized segments were advanced like two steps and fixed rigidly with miniplate. RESULTS: From June, 2004 to Dec, 2005, 10 cases with severe microgenia were treated with this technique. The duration of follow-up was six months. The mean chin advancement was 1.1 cm and the mean chin vertical increase was 0.7 cm. All the patients healed very well with satisfactory aesthetic result. CONCLUSIONS: With this two-step genioplasty, the chin can be moved to ideal position with a natural appearance. It is a reliable method for severe microgenia.

[Analysis of the complications following mandibular distraction using internal distractors].

OBJECTIVE: To investigate the causes and the prophylactic for the complications following mandibular distraction osteogenesis using internal distractors. METHODS: From 1997 to 2004, a total of 46 patients (61 sides) suffering from malformations or defects of mandible who underwent mandibular distraction osteogenesis were analyzed. The diseases included hemifacial microsomia in 27 cases, congenital or acquired mandibular hypoplasia and micrognathia bilateral in 8 cases and unilateral in 4 cases, electronical injury or postoperative mandibular defects in 3 cases, Treacher Collins syndrome in 2 cases, obstructive sleep apnea syndrome in 2 cases. RESULTS: Of them, 9 patients had postoperative complications, which included 3 patients had complications associated with distractors, local infection occurred in 2 cases, apertognathia of anterior teeth in 2 case, 2 patients had sinus of the skin of the lower lip. 9 patients had been aggressivly managed and obtained satisfactory results. CONCLUSIONS: The pivotal points to reduce complications are to understand the mechanism of mandibular distraction osteogenesis completely, and to be familiar with the anatomy of mandible and adjacent tissues. It is necessary to treat with it preoperatively and postoperatively.

[Surgical management of craniomaxillofacial fibrous dysplasia].

OBJECTIVE: To explore the method to obtain good aesthetic and functional results in surgical management of craniomaxillofacial fibrous dysplasia and correct the grotesque deformity. METHODS: According to the type of the lesions, different excision and reconstruction methods were used. RESULTS: 19 cases (4 monostotic cases and 15 polyostotic cases) were surgically treated. The period of follow-up range from 9 months to 5 years, all patients obtained satisfactory aesthetic and functional results. No relapse happened during follow up. CONCLUSIONS: Based on modern craniomaxillofacial techniques and computer aided design, extensive radical excision and craniomaxillofacial skeleton reconstruction could be safely accomplished, and the better results were obtained, both aestheticly and functionally.

[Applications of autogenous outer table of the calvarial and mandibular bone in posttraumatic deformities of the nose].

OBJECTIVE: To study the applications of bone grafts from the cranium or mandible in the repair of posttraumatic deformities of the nose. METHODS: From 1997 to 2002, a total of 44 patients, who presented with secondary nose deformity as well as facial fractures, were reconstructed by autogeneous outer table grafts of the calvarial or mandibular bone after facial skeleton reposition. In this series, 32 cases used the calvarial bone, 12 cases used the mandible bone, which was harvested through a coronal incision and an oral approach respectively. RESULTS: The surgical incisions healed primarily in all patients with minimal scar. The facial appearance was greatly improved. No implant infection, extrusion and shift were observed in the postoperative follow-up of 6 months to 2 years. There was not obvious bone resorption, nor donor site morbidity. CONCLUSION: Autogeneous calvarial and mandibular bone was an ideal material of bone graft in reconstruction of severe posttraumatic deformities of the nose. Compared with other autogeneous and alloplastic materials, the outer table of the calvarial and mandibular bone produced less morbidity of the donor site, invisible scar, no rejection and less resorption.

[Chin augmentation with bone transplantation from the mandible].

OBJECTIVE: To explore a new method for mentoplasty. METHODS: The bilateral prominent mandibular angle or outer lamina was resected through the intraoral approach. The resected bone fragments were shaped and rigid fixed to the chin with miniplates and screws. RESULTS: A total of 30 patients (28 females, 2 males) accepted chin augmentation with this method. The mandibular angle bone was used in 20 cases and the mandibular outer lamina was used in 10 cases. The operative results were satisfactory, and the patient's facial contour was improved substantially. CONCLUSION: No rejection reaction was found after this procedure. Chin augmentation with autogenous mandibular bone is an ideal method for genioplasty.

[Individual prefabricated titanium implant for the reconstruction of the skull bone defect].

OBJECTIVE: This paper presents a new method of individual prefabricated titanium implant for the reconstruction of the skull bone defect. METHOD: A computer-based 3D model of the cranial bone defect is created from helical CT-data and serves as the basis for the computer aided design and manufacturing (CAD/CAM) of the individual prefabricated titanium implant for the cranial bone defect reconstruction. RESULT: Since 2001, a total of nine patients suffering from the cranial bone defect have been operated on by this method with satisfied result. The fallow-up is 3 to 12 months. CONCLUSION: These individual prefabricated titanium implants have won a high precision, a good biomechanics and a excellent biocompatibility. It is a quite ideal and very simple method with much less complication for the surgical treatment of the cranial bone defect.

[Compositive treatment of square face].

OBJECTIVE: To investigate the treatment of square face with compositive methods. METHODS A total of 71 patients with square-shape face were treated. According to the different face skeleton and desire of patient, mandible angle curved-osteotomy and mentoplasty were used as main methods and zygomatoplasty, buccal fat pad resecting and other aesthetic methods as assistant methods to recontour the whole face skeleton. RESULTS: The face skeleton of all patients was improved with satisfaction. The following-up period was 6 months to 2 years. In this patients group, massive haemorrhage was occurred during operation in one patient, mental nerve of of one side was injured in two patients, the lip mucosa was wounded in five patients. CONCLUSION: Mandible angle curve-osteotomy and mentoplasty combined with other assistant aesthetic operations were ideal methods to recontour square face. The result was satisfactory.

[Surgical treatment of orbital and periorbital fibrous dysplasia].

OBJECTIVE: To explore the surgical approaches to obtain good aesthetic and functional results in the management of orbital and periorbital fibrous dysplasia and related deformities. METHODS: Ten cases of orbital and periorbital fibrous dysplasia were treated surgically. The location, extension and shape of the lesions were identified based on X-ray examination and two and three dimensions CT examinations preoperatively. According to the type of the lesion, different approaches were used to excise the lesion and to reconstruct the orbit. The lesions were radically or partially excised through bicoronal, intraoral and subciliary approach; the orbit was reconstructed with autogenous outer or inner table of calvarium, outer table of mandible, Medpor and prefabricated individual titanic implants. RESULTS: In 10 cases treated surgically, radical excision was employed in 4 cases and partial excision in 6 cases. Autogenous inner table of calvarium was used in 2 cases, Medpor in 2 cases, outer table of mandible in 1 case, and titanic meshwork and prefabricated individual titanic implants in 4 cases to reconstruct the orbit. After the treatment, all patients obtained satisfactory aesthetic and functional results. CONCLUSIONS: Carefully planed surgical approaches with methods for preventing the complications can be used for the treatment of orbital and periorbital fibrous dysplasia and obtaining satisfactory aesthetic and functional results.

[Secondary reconstruction of post-fracture deformities in the nasal-orbital ethmoid region].

OBJECTIVE: To study the surgical reconstruction of secondary fracture deformities of the nasal-orbital ethmoid area. METHODS: Typical bicoronal and subciliary incisions or the adjacent scar incision were employed to expose the fractured area. The flattened nasal bone was narrowed by curved osteotomy along the medial orbital rims and trimed with a bur. 2-3 pieces of cranial outer table were used to reconstruct the nasal framework, which were fixed to the frontal bone with mini-plates. After the medial orbital wall and orbital floor were exposed, the herniated orbital contents were released and reduced to the orbital cavity. The fractured orbital walls were repaired precisely with autogenous cranial outer table or Medpor. The medial canthal tendons were anchored superior-posteriorly to the lacrimal fossa with transnasal wires. RESULTS: From December 1996 to December 2001, 34 cases of severe nasal-orbital ethmoid fracture deformities were repaired with this technique. Of them, 12 cases had combined orbital-zygomatic fracture, 4 cases had fontal sinus fracture, 1 case had Le Fort II and 1 case had Le Fort III fracture. All the patients recovered well and their facial appearance improved greatly. CONCLUSIONS: The key points for surgical reconstruction of the periorbital post-fracture deformities are narrowing the flattened nasal root by curved osteotomy, the nasal framework reconstruction with autogenous bone graft, the orbital wall repair to correct enophthalmos, and most importantly, the medial canthal tendon reduction and canthal plasty.

[Correction of prominent malar complex by L-type osteotomy].

OBJECTIVE: To present a new method for correction of prominent malar complex by L-shaped osteotomy through an intraoral incision. METHODS: Based on the anatomical characteristics of the malar complex, we designed a new L-shaped osteotomy for malar eminence reduction. The procedure includes oblique incision of the upper part of the mala, vertical incision of the anterior part of the mala and "greenstick" fracture of the zygomatic arches. According to the severity of malar prominence, we resect part of the anterior-inferior part of the mala and lower the malar complex. RESULTS: This method was used in 39 patients with prominent malar complex. Of them, 32 were symmetrical and 7 were unsymmetrical. All the patients obtained good results. CONCLUSION: L-shaped osteotomy for correction of prominent malar complex is a relatively ideal surgical method with the advantages of simpler manipulation, fewer complications, better result, and ensuring the intactness of the structural characteristics of the malar complex.