Defect-related variations in mandibular reconstruction using fibula grafts. A review of 96 cases.

Despite the popularity of the donor region 'laterodorsal calf' with the fibula, the flexor muscles and the overlying skin for microsurgical bone and soft tissue transfer some limitations and possible pitfalls have to be considered. We report on 93 patients who had 96 reconstructions, 65 with and 31 without soft tissue transfer in 8 years using microvascular fibular grafts for mandibular replacement and oromandibular reconstruction. Six patients died within 4 weeks and eight flaps were lost. Necrosis of the skin paddle occurred in 7 (11%) of 61 cases with uncomplicated bony healing.

Impact of pulmonary metastases of the R1H-tumour on radiation tolerance of rat lung.

PURPOSE: The aim was to investigate the influence of pulmonary metastases of the rhabdomyosarcoma R1H on the radiation response of the lung of the WAG/Rij rat. MATERIAL AND METHODS: Three groups of animals were investigated: metastases-free animals treated with fractionated irradiation of the lungs; metastases-bearing animals receiving no irradiation; and metastases-bearing animals treated with fractionated irradiation initiated 14, 21 or 28 days after induction of pulmonary metastases of the R1H-tumour by i.v. injection of viable tumour cells. Metastases were thus treated at various well-defined sizes. Total doses of 20-60Gy were applied in fractions of 2 Gy within 11 days. Complication rate and survival time were used as endpoints. RESULTS: About 2 months after onset of irradiation treatment, animals had to be sacrificed because of severe respiratory distress either caused by irradiation-induced lung damage (median 57 days, range 36-77 days), or because of development of lung metastases (65, 20-160 days). A decrease of the ED(50) (dose required to induce lethal lung damage in 50% of irradiated animals) was determined for metastases-bearing animals. This effect increased with metastatic volume. CONCLUSIONS: The results suggest that the presence of tumours in the lung decreased the lung tolerance to radiation. This effect can hardly be explained by a reduction in functional lung volume by metastatic volume.

Impact of treatment acceleration and its timing on the response of the rhabdomyosarcoma R1H of the rat to fractionated irradiation.

BACKGROUND AND PURPOSE: In clinical practice a concomitant boost is usually given as a second daily dose to a reduced field. The question arises which part of treatment should be accelerated to achieve optimal tumor control. An experiment was performed on tumor bearing rats to determine the optimal timing of treatment acceleration for this experimental tumor system. MATERIAL AND METHODS: Rhabdomyosarcoma R1H of the rat were treated applying 30 fractions in an overall treatment time of 40-42 days, up to total doses ranging from 67.5 to 97.5 Gy were administered. For control a standard treatment was given as continuous treatment applying one fraction per day. A boost of five additional fractions was given as a second fraction during 5 days. Three experimental arms received a boost either in the 1st, 4th, or in the last week of treatment. Treatment outcome was assessed using tumor control as endpoint. RESULTS: All experimental arms proved more effective than the standard treatment. Treatment was most effective when the boost was administered in the 1st week of treatment. A TCD37% of 87.1 Gy (95% CI: 82.8 ... 92.7 Gy), 96.5 Gy (89.9 ... 107.1), and 107.3 Gy (97.2 ... 131.0) was determined, when the boost was given in the 1st, 4th, or last week of treatment, respectively. The observed difference between the experimental arms was statistically significant (p = 0.004). CONCLUSIONS: Initially accelerated treatment schedules were found to be more effective for tumor control in an experimental tumor system.

Impact of the position of a gap on the response of the R1H-tumor of the rat on fractionated split-course radiotherapy.

BACKGROUND: Gaps are a common feature of clinical radiotherapy. Only little information is available about the influence of the position of a gap on tumor response. MATERIAL AND METHODS: In a rodent tumor model (rhabdomyosarcoma R1H of the rat) three split-course schedules were carried out by inserting a 2-week gap either after the 1st, the 3rd, or the 5th week into a standard schedule of 30 fractions in 6 weeks. For comparison a standard and an accelerated treatment were carried out. RESULT AND CONCLUSION: The position of the gap was found to have a significant influence on the tumor response (p = 0.018).

Single photon emission tomography: scintigraphy in the assessment of mandibular invasion by head and neck cancer.

BACKGROUND: This study was performed to determine the effectiveness of single photon emission tomography (SPET) in contributing to the initial staging of patients with cancers of the head and neck because information about osseous infiltration of head and neck cancer is of major importance for staging and planning of treatment. METHODS: A retrospective analysis of 89 cases with probable tumor infiltration of the mandible by oral/pharyngeal cancer was undertaken by comparing the preoperative SPET as well as CT-scans, if available, with clinical and postoperative histological examinations. RESULTS: For SPET examinations, a sensitivity of 95% and a specificity of 48% were calculated. The positive predictive value was 65%, and the negative predictive value was 93%. CT scans showed a sensitivity of 75% and a specificity of 78%. The positive predictive value was 65%, and the negative predictive value was 93%. CONCLUSIONS: SPET is a powerful method to detect infiltration of carcinomas into the head and neck skeleton. Its sensitivity is high and superior to CT scans, although the specificity is small due to a high number of false positive results.

Combined modality treatment of bone metastases: response of the rhabdomyosarcoma R1H of the rat to postoperative irradiation combined with local release of daunorubicin from acrylic cement.

Reconstruction techniques for pathological fractures caused by bone metastases often include acrylic cement to stabilise defects. The aim of this study was to test in a rodent model, whether outcome could be improved by local chemotherapy from an anticancer drug added to the acrylic cement. Tumour excision 17 days after transplantation into the femur was followed by fractionated irradiation. Supplementation of acrylic cement with daunorubicin led to a considerable reduction of TCD37% from 72.9 Gy (62.2-82.8) to 29.3 Gy (21.8-37.5) (P = 0.0007). Local chemotherapy diffusing from bone cement combined with postoperative radiotherapy was highly effective in the experimental system studied.