Mandibular reconstruction using customized three-dimensional titanium implant

Mandibular defects lead to severe deformation and functional deficiency. Vascularized osteocutaneous tissue has been widely used to reconstruct the mandible. However, it is technically challenging to shape this type of grafts in such a manner that they resemble the configuration of the mandible. A 48-year-old female patient who underwent anterolateral thigh (ALT) flap coverage after a tongue cancer excision was diagnosed with a tumor recurrence during the follow-up. A wide excision mandibulectomy and mandibular reconstruction with an ALT flap and a titanium implant were performed. The prefabricated titanium implant was fixed to the condyle. Then, an ALT flap was harvested from the ipsilateral thigh and anastomosed. After confirming that the circulation of the flap was intact, the implant was fixed to the parasymphysis. On the radiograph taken after the surgery, the prosthesis was well positioned and overall facial shape was acceptable. There was no postoperative complication during the follow-up period, 1 year and 2 months. The prefabricated implant allows the restoration of facial symmetry without harvesting autologous bone and it is a safe and effective surgical option for mandibular reconstruction.

Three-dimensional finite element models of advancement skin flap and simulation analysis based on skin biomechanical features / 中华医学美学美容杂志

Objective To build three-dimensional (3-D) finite element models for local advancement skin flap, by which the post-operative local strain and local stress of skin were figured out to assist in the design of skin flap in clinic. Methods The biomechanical parameters of human forehead skin were obtained in vitro from biomechanical experiments. The 3-D finite element model of local advancement skin flap was set up by MSC Marc/Mentat 2005 (3-D finite element software). Six models were built with the same flap but different skin defects, to simulate post-operative local strain of skin and local stress of skin in different models. Results Post-operative local stress of skin increased with the skin flaps stretching, but the relationship between increase and stretching did not meet the linear rule. Skin flap was able to stretch to 40 % of its initial length in theory if we did not consider blood supply of it. When the skin flap stretched over 40 % of its initial length, the maximal stress could exceed the yield limit. Conclusion It is an effective and workable way to simulate local advancement skin flap using 3-Dfinite element model and biomechanical parameters of human skin. The stretch ratio of local advancement skin flap should be not over 40% for safety.