Comparison Between Internal and External Distractors in Osteogenesis

The study will be conducted on 30 patients who are suffering mandibular problems either congenital acquired or post tumor mandibular resection that requires lengthening of the mandible, attending the outpatient clinic of Plastic Surgery Department in Ain Shams University Hospital \& Assiut University Hospital. Preoperative assessment: * Informed consent will be obtained from all patients before their inclusion in the study. * Photographs will be taken for the patient in lateral, antro-posterior and oblique positions preoperative. * Lateral cephalometric radiographs or computed tomography (CT) or cone beam CT scans will be done for each patient pre-operatively. * The decision to perform internal or external device will be based on preoperative and intraoperative considerations, such as anatomical bony characteristics affecting the possibility to place internal devices and patient cooperation. Principles of the operation: * anaesthesia: general anesthesia. * Intraoperative consideration of internal versus external distractor is decided depending on the availability of bone stock. * Osteotomy will be done according to each case individually making sure that it suits the vector of distraction required for each case. * The approach for the external devices will be intraoral between the mental nerve anteriorly and gonial area posteriorly on both sides of the mandible. * The approach for internal devices will be intraoral. While preserving the mandibular branch of the facial nerve. * After 3-5 days of latency period for callus organization, gradual lengthening of the mandible will be performed at a rate of 0.5 mm twice a day for a total of 1 mm per day until achieving desired length. Postoperative management and assessment: * The patient will take broad spectrum and anaerobic antibiotics, anti-edematous, analgesic in addition to supportive treatment. * After 3-5 days of latency period for callus organization according to patient age and condition, gradual lengthening of the mandible was performed at a rate of 0.5 mm twice a day for a total of 1 mm per day until achieving desired length. * Following distraction phase there will be consolidation phase that will not be less than 8 weeks. * Removing of internal or external distractor device and start retention phase if required with assistance of orthodontic appliances to avoid relapse. * The patients will be evaluated with lateral cephalograms and head CT to assess the changes and amount of new bone formation following distraction.