Reconstruction of complex defects involving the maxilla or mandible often requires transfer of free vascularized tissue. In the conventional approach, a flap is transferred to provide vital tissue, and subsequent shaping and debulking are required. The authors present their experience with prefabrication of vascularized fibular flaps. Since 1999, 48 prefabricated flaps have been used to reconstruct 28 maxillary and 20 mandibular defects. The technique involves two surgical steps (prefabrication and flap transfer) and requires accurate planning, done with a solid model of the skull. Correct positioning of the prefabricated flap is accomplished by using the occlusion as a guide. Planning includes fabrication of a provisional prosthesis that is fixed to the flap with implants. Putting the prosthesis into occlusion determines the position of the flap.

BACKGROUND:Conventional maxillofacial reconstruction often leads to suboptimal results due to inaccurate planning or surgical difficulties in adjusting a free flap and osteosynthesis plates into a three-dimensional defect. OBJECTIVES:To justify the importance of patient-specific intraoperative guides in complex maxillofacial reconstruction. CLINICAL EXAMPLE: A 40-year old patient underwent a left hemimaxillectomy for an adenoid cystic carcinoma of the palate. Six years later, massive recurrence required radical resection of the left orbit and reconstruction with cranial bone grafts and a free latissimus dorsi flap. Postoperative radiotherapy resulted in local osteoradionecrosis. Surgical revision and restoration of the maxillary defect with a prefabricated fibula flap was performed. The authors provide ample information on the application of computer-aided design and manufacturing (CAD-CAM) and rapid prototyping at each reconstructive step. DISCUSSION:Stereolithographic models enable simulation of the resective and reconstructive phases, prebending of reconstruction plates and fabrication of surgical guides. CONCLUSIONS:Optimal restitution of complex maxillofacial defects requires meticulous planning of the surgical and prosthetic phases and effective transfer of the plan to the operating room through patient specific guides. CAD-CAM technology and stereolithographic models represent an effective strategy to achieve this. Improved patient outcomes and intraoperative efficiency certainly offset the inherent increase in costs.

Purpose: The purpose of this study was to evaluate the error magnitude in the clinical application of face-bow devices. Technical and methodologic inaccuracies, as well as deviations from reference planes, were determined.Materials and Methods: The presented method is part of a 3-dimensional virtual planning procedure for orthognathic surgery and included 15 patients with dentoskeletal deformities. Cone beam computed tomography datasets obtained from patients with a referenced face-bow plane and a centric registration splint were matched with cone beam computed tomography datasets of the registered plaster model of the maxilla mounted in an articulator. To assess potential sources of methodologic errors, angulations were measured between the virtual face-bow plane and the horizontal cross bar of the virtual articulator. To evaluate the reproducibility of the anatomic reference plane, angulations between the Frankfort plane and the horizontal cross bar of the articulator were measured. Statistical significance was set at P < .05 and tested by univariate analysis of variance.Results: Technical and methodologic errors showed a mean deviation of 3.5 degrees, with a median of 3.6 degrees and SD of 2.7 degrees. The values did not reach statistical significance (P = .1). However, there was a significant error (P < .05) in determining the position of the anatomic reference plane by face-bow transfer. The mean deviation was 7.7 degrees (values ranged between 1.2 degrees and 18.9 degrees), with a median of 6.7 degrees and SD of 5.3 degrees.Conclusions: In this study the traditional use of face-bow devices showed inaccuracies in model mounting as well as in assignment of anatomic reference planes. Three-dimensional virtual computer-assisted planning seems to be more accurate than conventional methods. (C) 2012 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 70:1944-1950, 2012

We present an efficient method that uses particles to solve the 2D shallow water equations. These equations describe the dynamics of a body of water represented by a height field. Instead of storing the surface heights using uniform grid cells, we discretize the fluid with 2D SPH particles and compute the height according to the density at each particle location. The particle discretization offers the benefits that it simplifies the use of sparsely filled domains and arbitrary boundary geometry. Our solver can handle terrain slopes and supports two-way coupling of the particle-based height field with rigid objects. An improved surface definition is presented that reduces visible bumps related to the underlying particle representation. It furthermore smoothes areas with separating particles to achieve better rendering results. Both the physics and the rendering are implemented on modern GPUs resulting in interactive performances in all our presented examples.

The fibular flap can be used for a variety of indications. Recently, the treatment of four patients with severely atrophied upper jaws using a method to prefabricate the vascularized fibular graft has been published. This technique consists of a two-stage operation procedure that allows simultaneous prosthodontic rehabilitation and immediate placement of dental implants. In this paper eight patients with 29 ITI implants (Straumann AG, Waldenburg, Switzerland) who had reconstruction of either the upper or lower jaw are presented. The aim of the study was (i) to evaluate the behavior of the newly formed soft tissue around implants inserted in the fibula by applying periodontal parameters, (ii) to monitor prospectively the integration of the implants in the fibular graft, and (iii) to assess the osseous integration of the fibular graft used for reconstruction of the upper or lower jaw. Two implants failed during the observation time because of avascular bone at the distal end of the fibular graft. Stabilization of the graft, however, was never compromised. Due to the prefabrication firmly attached gingiva-like soft tissue could be provided preventing periimplant soft tissue inflammation and facilitating oral hygiene. After 1 year of observation the mean attachment level was similar to implants placed in original bone whereas vertical bone loss measured radiographically was lower in the present study. This may indicate that the remodeling of a bicortical bone requires a longer period of time compared with the bone of the alveolar crest. The prospective 1-year results are promising but long-term evaluation of periodontal and radiological parameters are required.