Calvarial bone graft in reconstructive rhinoplasties

161 antenna attached to the silicone pad combination with a custommade dental registration splint. Methods: The splint was made of an acrylic resin and had an anterior extension using contrast resin; it incorporated a total of five holes for marker-based pair-point registration. The splint allowed rigid stability of the patient who required Le Fort I osteotomy while cone-beam computed tomography (CBCT) was taken. CBCT data was used for preoperative planning and intraoperative navigation. The reference antenna attached to the silicon pad was adapted to nasion of the patient. The registration process was conducted by means of the fiducial markers incorporated in the splint. Results: There was improvement of navigation accuracy by using present surgical navigation management. Furthermore, no significant error and surgical complications were detected. Conclusion: Our method for surgical navigation system is a promising tool aiming to improve the safety and precision of orthognathic surgery. http://dx.doi.org/10.1016/j.ijom.2017.02.552 Calvarial bone graft in reconstructive rhinoplasties R. Lamartine Monteiro ∗ , A. Lemaitre, Y. Deniz, C. Aubert, M. Shahla, Y. Vanhemelrijck, D. Dequanter, P. Lothaire CHU Charleroi, Belgium In most cases of rhinoplasty a resection of the nasal osseocartilaginous framework is sufficient to achieve aesthetic or functional objectives. Saddle nose is seen in patients who lose loss structural integrity with subsequent collapse. Various causes could be the result of this deformity that include traumatic, congenital, iatrogenic (secondary to reduction of nasal dorsum, drug abuse, infection and granulomatous diseases). When a nasal defect involves all or part of the bony pyramid, the missing portion of the nasal bone is usually replaced with autologous bone grafts which are sculpted to the defect and are secured to the remaining bony and cartilage framework. Different types of graft materials are used to the reconstruction of the nasal framework like iliac bone, cranial vault, rib bone and cartilage, bone bank, synthetic material. Many grafting techniques have been described for use in primary or revision rhinoplasties. We reviewed a series of 100 patients using cranial vault as the preferential bone graft for nasal reconstruction over the past 10 years. A ‘L-shaped’ framework is mostly used and bone grafts are assembled and fixed using titanium screws. Cranial bone grafts is an efficient technique for nasal reconstruction achieving good functional and aesthetics results. Evaluations were made by radiographic findings and postoperative photographs. http://dx.doi.org/10.1016/j.ijom.2017.02.553

335 Accuracy of three-dimensional natural head position recording modalities M.Y. Leung ∗ , J. Lo, Y.Y. Leung The University of Hong Kong, Hong Kong Background: Three-dimensional (3D) images are acquired with stabilisation device(s) to minimise image artefacts. These device(s) positioned the patient’s head into a random orientation. Reorientation of the 3D images into natural head position (NHP) is a prerequisite for proper assessment of dentofacial deformities. Objective: The objectives were to evaluate the emerging technologies to record NHP in 3D and to compare their accuracy. Methods: A systematic review of the Cochrane Library, PubMed and Embase database was performed in four rounds. The advantages, limitations and accuracies of the modalities to record NHP in 3D were compared. Findings: Eight articles were included. Six 3D NHP recording modalities were identified. Digital orientation sensing had good accuracy, with mean angular differences from the reference of less than one degree. Laser scanning was shown to have comparable accuracy. The modality involving clinical photo and pose from orthography and scaling with iterations (POSIT) algorithm was also accurate, with less than 1◦ mean angular differences in pitch, roll and yaw. Stereophotogrammetry had the highest reliability with the mean angular deviations in pitch, roll, and yaw within 0.1◦ . Conclusion: Digital orientation sensor and laser scanner were shown to accurately record NHP in 3D. Routine use of laser scanner was difficult due to its high cost and bulkiness. Stereophotogrammetry and the modality utilising clinical photograph and POSIT algorithm were possible alternatives. http://dx.doi.org/10.1016/j.ijom.2017.02.554 Distraction osteogenesis of the mandible: does postoperative infection affect stability? T.S. Li ∗ , W.S. Choi The University of Hong Kong, Hong Kong Background: Up to the present time, no study has attempted to explore a possible association between skeletal stability and postoperative infection in mandibular advancement by distraction osteogenesis. Objectives: To determine any possible association between postoperative infection and skeletal stability of mandibular advancement by distraction osteogenesis for the treatment of Skeletal Class II patients. Methods: Retrospective study of 20 Class II patients previously treated by distraction osteogenesis for mandibular advancement. Clinical records of these patients were reviewed and lateral cephalograms were used. Prevalence and duration of postoperative infection were recorded. Skeletal relapse was calculated based on serial hand tracings of lateral cephalograms. Statistical analysis of the data was performed to determine any association between prevalence and duration of postoperative infection and skeletal relapse.