BACKGROUND: There is nearly no muscle tissue with satisfactory function and appearance applying in clinical repair and construction of injured muscles to date. OBJECTIVE: To investigate the feasibility of applying autologous fascia as a scaffold to construct muscle in vivo. DESIGN, TIME AND SETTING: The randomized, self-matched control experiment was carried out between January 2004and June 2006 at Department of Burns & Plastic Surgery, Second Hospital of Shenzhen, Shenzhen, Guangdong Province, China MATERIALS: Twenty-eight healthy New Zealand rabbits, weighing (1.7±0.5) kg, without sex restriction, establishing middle part defect model of anterior tibial muscle of rabbit hind legs. METHODS: One hind leg of each rabbit was randomized to the experimental group (n=28), the other hind leg was assigned to one of 3 control groups, scaffold-connected group (n=10), muscle particle implant group (n=10) and blank control group(n=8). In experimental group, the defect was connected with an autologous fascial scaffold and filled with the mutilated muscle particles, and subcutaneous tissue and skin were sutured in situ. In scaffold-connected group, the treatments were same to the experimental group only except muscle particle implantation. In muscle particle implant group, the defect was filled with muscle particles but without fascial scaffold and other treatments were same to the experimental group. The defect in blank control group received no treatment. MAIN OUTCOME MEASURES: The success rate of muscle transplantation, histological and ultra structural observation,and immunohistochemical identification of desmin were observed at 2, 3, 4, 6 and 9 weeks after operation. The middle parts of samples were also harvested for relative quantitative analysis of α-actin cDNA using reverse transcription-polymerase chain reaction in the experimental group and scaffold-connected group.RESULTS: In experimental group, 1 muscle broke near the proximal junction, the other 27 succeeded and the appearance of healed defects became near normal gradually. In scaffold-connected group, 4 muscles broke, 6 muscles still depressed in defect area; in muscle particle implant group and blank control group, the defects had no change. In experimental group, a large quantity of skeletal muscle satellite cells proliferated, which reached peak at 2-3 weeks, cells attached to the ends of fibrous connective tissue; in scaffold-connected group only fibrous connective tissue was seen. lmmunohistochemistry showed that 85% cells in experimental group were desmin-positive, while the positive rate in scaffold-connected group was < 25%. The relative quantitative analysis of α -actin cDNA showed that there were significant differences between the experimental group and scaffold-connected group at different time points(P < 0.05).CONCLUSION: The success rate of repairing muscle defect with autologous fascial scaffold reached 93.33%, which indicates that it is feasible to promote muscle regeneration with autologous fascial scaffold.

BACKGROUND:Lingual movable wing is a new type of lingual orthodontic technique and the different stretching lengths of the wring affect the torque control effect of anterior teeth.However,there is yet no related biomechanical research. OBJECTIVE:To investigate the displacement trend of dentition during adduction of mandibular anterior teeth and the effect of different wing stretching lengths on the biomechanical effect of mandibular anterior teeth. METHODS:The data of the mandible and lower dentition were collected by cone-beam CT and reconstructed using Mimics software to establish a three-dimensional finite element model of mandibular anterior teeth adducted by the lingual movable wing.The ANSYS software was used to analyze the initial displacement of the mandibular anterior teeth under the following conditions:A,2 mm stretching length;B,2.5 mm stretching length;C,3 mm stretching length;and D,3.5 mm stretching length. RESULTS AND CONCLUSION:The trend of initial displacement of lower dentition:The central incisors moved lingually with depression,the lateral incisors and canines moved mildly lingually with mesial lingual torsion,the second premolar was tilted distally with a marked lingual inclination and the first molar showed an overall mesial inclination with mesial crown eversion.Therefore,in the adduction cases of mandibular tooth extraction,attention should be paid to the lingual movement of the second premolar,which could be offset by corresponding techniques in clinic.The trend of anterior tooth displacement in all directions:from condition A to condition D,in the sagittal direction,the difference value in crown-root displacement of central incisors changed from-11.891 μm to-5.757 4 μm,indicating that the central incisor changes from oblique movement to overall movement.The difference value in crown-root displacement of lateral incisors changed from-11.828 1 μm to-6.711 45 μm,and that of canines changed from-7.572 3 μm to-4.695 5 μm,indicating that the oblique movement of the lateral incisors and canines is also changing to an overall movement.In the vertical direction,from condition A to condition D,the reduction of incisors was gradually increased,while that of canines was gradually decreased.These findings indicate that the stretching length of the wing can affect the oblique movement trend of the anterior teeth.As the wing continues to stretch,the torque control of the lower anterior teeth will become better.