Long-term biomechanical donor site morbidity after radial forearm free flap

Long-term biomechanical donor site morbidity after radial forearm free flap

189 Objectives: The purpose of this study was to evaluate the feasibility of the novel design of the double-barrelled fibular flap from virtual surger...

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189 Objectives: The purpose of this study was to evaluate the feasibility of the novel design of the double-barrelled fibular flap from virtual surgery to actual result. Methods: From 2012 to 2016, 52 patients underwent segmental mandibular reconstruction with double-barrelled fibular osteoseptocutaneous flaps with computer-aided design/computer-aided manufacturing technic. Preoperative computer tomographic (CT) scans were imported into Mimics 10.01 software (Materialise, Leuven, Belgium) for surgical planning. The double-barrelled bone was strung with 16 mm fixation screws instead of miniplate. 63 dental implants placement were simultaneous in 30 patients and 32 dental implants placement were in second stage in 18 patients. Postoperative CT and digital imaging were evaluated to assess surgical accuracy using software. The pre- and postoperative morphometric measurements were compared using the Student t test. Results: Two flaps occurred vascular crisis postoperatively. There was no flap necrosis. One hundred four CT scans from 52 patients who underwent partial mandibular resection were analysed. The dimensions of the double-barrelled fibula segments after osteotomy showed no difference from the preoperative virtual surgical planning (VSP). But the condylar locations showed a disposition out of the fossa (P < 0.05), between VSP and postoperative CT scans. There was no difference in implants between VSP and postoperative CT scans. Conclusions: The VSP of relationship of double-barrelled fibular is important for segmental mandible reconstruction. The benefit of VSP was to enhance surgical accuracy and safety. http://dx.doi.org/10.1016/j.ijom.2017.02.645 Computer-aided design/computer-aided manufacturing versus conventional fixation methods for mandible reconstruction: a biomechanical in vitro study C. Rendenbach ∗ , L. Gerbig, G. Huber, K. Sellenschloh, M. Morlock, R. Smeets, B. Beck-Broichsitter, M. Heiland, H. Hanken University Medical Center Hamburg Eppendorf and Technical University Hamburg, Germany Background: There are several methods for osseous fixation in mandible reconstruction with a trend towards computer-aided design/computer-aided manufacturing (CAD/CAM) plates. There a no studies comparing biomechanical aspects of conventional plates with CAD-CAM fixation systems to date. Objective: The aim of this study was to determine the plate with the highest fatigue strength. Methods: We designed a polyurethane mandible reconstruction model (Synbone, CH) with cortical and cancellous equivalents. Three different fixation systems with each six specimen were tested. Mandible reconstruction of a right-sided two-segment defect was performed with either miniplates (Group A), a conventional 2.0 mm reconstruction plate (Group B) or an individual CAD-CAM plate (Group C) [Depuy Synthes, Germany]. Mastication was simulated via cyclic dynamic testing using a universal testing machine (MTS, Bionix, Eden Prairie, MN). Specimens were tested at a rate of 1 Hz with increasing load application (+0.15 N/cycle) on the left side. Findings: Material failure in the miniplate group occurred at 51.920 simulated bite cycles on average (corresponding to a load of 0.56 ± 0.4 kN). CAD CAM and reconstruction plates failed at 0.66

and 0.65 kN on average. Material stiffness was higher (+70 N/mm) in the CAD CAM group. Plate breakage appeared in groups A and B, while screw breakage was recorded as failure mechanism in Group C. Conclusion: All three tested fixation methods seem sufficiently stable for mandible reconstruction. For two-segmental defects, rigid fixation seems to be better in reconstruction plates compared to titanium miniplates. http://dx.doi.org/10.1016/j.ijom.2017.02.646 Long-term biomechanical donor site morbidity after radial forearm free flap C. Rendenbach ∗ , C. Kohlmeier, H. Kreiker, A.T. Assaf, H. Hanken, A. Rashad, R. Smeets, M. Heiland, B. Riecke University Medical Center Hamburg Eppendorf, Germany Background: Although the radial forearm free flap (RFFF) is a commonly used microvascular graft for head and neck reconstruction, long-term biomechanical results regarding donor site morbidity are rare. Objective: To evaluate long-term functional outcome after RFFF. Methods: In a prospective study 32 patients underwent biomechanical assessment preoperatively, three month postoperatively and two years postoperatively. Both the donor and the contralateral arm were examined. The primary endpoint of the study was grip strength. Further, Mayo-Wrist-score, DASH-score, fine motor skill strengths (tip pinch, key pinch, palmar pinch) and the range of motion were analysed. Primary defects were closed with local fullthickness skin grafts (FTSG) from the donor site forearm avoiding a secondary defect site. Results: In the long-term analysis, grip strength was reduced in both arms. A significant improvement over time was found only for the donor arm. A persistent deficit of tip pinch strength and dorsal extension was recorded. Persistent sensory limitations occurred in 4 cases. Patient satisfaction after two years of follow up was high and daily life routine was not restricted. Conclusion: Gross and fine motor skill limitations are reversible short-term effects after RFFF harvesting and do not restrict daily routine in the long-term. These findings substantiate the value of the RFFF as a workhorse reconstructive surgery. http://dx.doi.org/10.1016/j.ijom.2017.02.647 Prefabrication of customised polymethylmethacrylate implants in cranioplasty and the mechanical properties of polymethylmethacrylate versus polyetheretherketone A. Ridwan-Pramana ∗ , J. van Loon, N. Liberton, S. te Slaa, F. Verver, J. Wolff, T. Forouzanfar Department of Oral and Maxillofacial Surgery/3D Innovationlab VU University Medical Center, Amsterdam, The Netherlands Background: The two most widely used implant materials in cranioplasty are polyetheretherketone (PEEK) and polymethylmethacrylate (PMMA). PEEK has been used for the last two decades in cranial surgery, due to its excellent biocompatibility, good mechanical strength and radiographic translucency. PMMA has a relatively low cost and has an extensive track record dating back to the 1940s. Sterilisation is a mandatory process for