Osteoradionecrosis following treatment for head and neck cancer and the effect of radiotherapy dosimetry: the Guy's and St Thomas' Head and Neck Cancer Unit experience.

OBJECTIVES: To analyze clinical features, dosimetric parameters, and outcomes of osteoradionecrosis (ORN). STUDY DESIGN: Thirty-six patients with ORN who had been previously treated with radiotherapy (RT) were retrospectively identified between January 2009 and April 2014. ORN volumes were contoured on planning computed tomography (CT) scans. Near maximum dose (D2%), minimum dose (Dmin), mean dose (Dmean), and percentage of bone volume receiving 50 Gy (V50) were examined. Clinical and dosimetric variables were considered to compare ORN resolution versus ORN persistence. RESULTS: Median interval time from end of RT to development of ORN was 6 months. Of the ORN cases, 61% were located in the mandible. Dmean to affected bone was 57.6 Gy, and 44% had a D2% 65 Gy or greater. Smoking was associated with ORN persistence on univariate analysis, but no factors were found to impact ORN resolution or progression on logistic regression. CONCLUSIONS: Prevention strategies for ORN development should be prioritized. Dose-volume parameters could have a role in preventing ORN.

Free vascularised iliac crest graft: an audit of 26 consecutive cases.

Over an 18 month period 26 vascularised myo-osseus, and one myo-osseus-cutaneous iliac crest flaps were used to reconstruct 18 mandibular and eight maxillary defects. During the operation one flap failed to reperfuse and was removed. Postoperatively three patients were returned to theatre for appraisal and reanastomoses, which in two cases involved thrombolysis. In all three salvage was deemed successful but in all there was partial muscle necrosis. There were 10 cases of anaesthesia of the skin supplied by the lateral cutaneous nerve of the thigh, three incisional hernias, one wound dehiscence in the thigh, two oronasal fistulas, one wound dehiscence in the neck, one infection by methicillin resistant Staphylococcus aureus in the thigh, and two long-term and one medium-term disturbances of gait. Complications were graded as severe (4%), intermediate (27%), and minor (46%).

Trismus following radiotherapy to the head and neck is likely to have distinct genotype dependent cause.

OBJECTIVES: Trismus frequently occurs as a consequence of radiotherapy or chemo-radiotherapy to the head and neck, with a loss of function that can reduce the overall quality of life. Radiation can trigger an intense fibrosis within the masticatory muscles and transforming growth factor beta 1 (TGF ß1) is involved in this process. As in other tissues the degree of fibrosis may be related to a single nucleotide polymorphism; C-T at position -509 in the TGF ß1 gene. MATERIALS AND METHODS: Trismus was measured in 62 patients before and after radiotherapy or chemoradiotherapy, blood was taken for DNA extraction, and genotype analysis of the TGF ß1 gene. Trismus was analysed against, patient age, sex, tumour site and stage, radiotherapy, and chemotherapy. RESULTS AND CONCLUSIONS: After radiotherapy or chemo-radiotherapy the reduction in mouth opening was shown to be significantly related to the presence of the T allele (p<0.001), with patients homozygous the most likely to be severely affected. No other patient, tumour or treatment factors were significant. Hence the TGF ß1 genotype is likely to be an important predictor of the degree of post radiotherapy or chemo-radiotherapy trismus.

Factors affecting survival and usefulness of implants placed in vascularized free composite grafts used in post-head and neck cancer reconstruction.

BACKGROUND: Bone-containing vascularized grafts have been used successfully to reconstruct post-cancer surgical defects. Dental implants can be placed in these bone-containing grafts to allow implant-supported prosthodontic reconstruction of these patients. PURPOSE: The aim of this study was to evaluate the survival of dental implants used in the rehabilitation of subjects treated with bone-containing vascularized grafts to compare usability of implants placed at the time of reconstruction and after healing. MATERIALS AND METHODS: A cross-sectional study was undertaken to examine survival rates of implants placed in vascularized bone-containing grafts either immediately at the time of surgical reconstruction or after 3 months healing. Other factors such as graft type, whether radiation therapy was given, and implant type were recorded. RESULTS: A total of 41 patients had 145 implants placed in 47 vascularized bone-containing flaps. Increased failure rate of implants was seen in immediately placed implants. There was also a significant increase in the number of osseointegrated implants that were prosthodontically unusable or sub-optimally placed in the immediate placement group. Radiation therapy was associated with a significant increase in failure rate. Modern implant surfaces appeared to perform better than machined/turned surfaces. Graft donor site did not influence implant survival. CONCLUSION: This study demonstrated the difficulties encountered with immediate placement of dental implants at the time of post-cancer reconstructive surgery.