Effect of postoperative radiation therapy on mandibular reconstruction using a modular endoprosthesis - a pilot study.

The endoprosthetic system has been shown to be a potential option for mandibular reconstruction. The objective of this pilot in vivo animal study was to determine the effects of postoperative radiation using brachytherapy on bone and soft tissue healing in mandibles reconstructed with the endoprosthesis. Six adult Macaca fascicularis mandibles were reconstructed with a cemented endoprosthesis after segmental body resection. The animals were divided into two groups. The test group was subjected to radiation therapy 1 month postoperation while the control group did not receive any radiation. Results showed no major radiation side effects. Mucosal ulcerations and wound dehiscence at the radiated sites healed within 4 weeks. One animal from each group had prosthesis failure and was unable to complete the study. Micro-CT findings indicated no significant differences between the total bone volume percentage (TBV%) of the study and control groups. Histomorphometrical analysis using grading scales also showed no significant differences between the two groups. Under the study conditions, postoperative brachytherapy did not affect the tissue response around the endoprosthesis within the early 6 months postradiation period. The endoprosthesis, therefore, remains a viable reconstructive option when postoperative radiation is prescribed.