PubMed · 7464597
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J C McNeur. 1980-11-15. Orthopaedics.. https://pubmed.ncbi.nlm.nih.gov/7464597/
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PURPOSE: To determine the dose perturbation effects at the tissue-metal implant interfaces in head and neck cancer patients treated with 6 MV and 10 MV photon beams. METHODS AND MATERIALS: Phantom measurements were performed to investigate the magnitude of dose perturbation to the tissue adjacent to the titanium alloy implants with (100 mu and 500 mu thick) and without hydroxylapatite (HA) coating. Radiographic and radiochromic films were placed at the upper (and lower) surface of circular metal discs (diameter x thickness: 15 x 3.2, 48 x 3.2, 48 x 3.8 mm2) in a solid water phantom and were exposed perpendicular to radiation beams. The dosimeters were scanned with automatic film scanners. Using a thin-window parallel-plate ion chamber, dose perturbation were measured for a 48 x 3.2 mm2 disc. RESULTS: At the upper surface of the tissue-dental implant interface, the radiographic data indicate that for 15 x 3.2 mm2 uncoated, as well as 100 mu coated discs, dose perturbation is about +22.5% and +20.0% using 6 MV and 10 MV photon beams, respectively. For 48 x 3.2 mm2 discs, these values basically remain the same. However, for 48 x 3.8 mm2 discs, these values increase slightly to about +23.0% and +20.5% for 6 MV and 10 MV beams, respectively. For 48 x 3.2 mm2 discs with 500 mu coating, dose enhancement is slightly lower than that obtained for uncoated and 100 mu coated discs for each beam energy studied. At the lower interface for 15 x 3.2 mm2 and 48 x 3.2 mm2 uncoated and 100 mu coated discs, dose reduction is similar and is about -13.5% and -9.5% for 6 MV and 10 MV beams, respectively. For 48 x 3.8 mm2 discs, dose reduction is about -14.5% and -10.0% for 6 MV and 10 MV beams, respectively. For 48 x 3.2 mm2 discs with 500 mu coating, the dose reduction were slightly higher than those for uncoated and 100 mu coated discs. CONCLUSIONS: For the beam energies studied, dose enhancement is slightly larger for the lower energy beam. The results of dose perturbation were similar for 100 mu coated and uncoated discs. These results were slightly lower for the 500 mu coated discs but are not clinically significant. The dosimetry results obtained from radiochromic films were similar to the ones obtained from radiographic film. The dose enhancement results obtained from ion chamber dosimetry are higher than those obtained from film dosimetry. The ion chamber data represent the data at "true" tissue-titanium interface, whereas the ones obtained from film dosimetry represent the data at film-titanium interface.
Fifty two patients with chest wall resection were reviewed, with emphasis upon 16 patient with chest wall reconstruction. The latter 16 patient consisted of 6 with metastatic tumor, 3 of primary lung cancer, 2 of breast cancer, one of primary chest wall tumor, and others. Before 1985, reconstruction after chest wall resection was conducted in four cases by using methyl methacrylate (Resin). One patient developed erosion of the overlying skin due to protrusion of the edge of Resin-plate with delayed wound healing. Since 1986, we have employed muscle or myocutaneous flap and/or Marlex mesh in reconstruction of the chest wall defect. Twelve patients underwent surgery in this way. Neither paradoxical movement of the chest wall nor respiratory distress developed in the postoperative course of any patient. Thirty six of fifty two patients underwent chest wall resection without following reconstruction as in the former group. Of them one patient of anterior chest wall resection developed respiratory failure. We conclude that rib resection involving as many as three or more in the anterior chest wall, or four rib resection or more in the lateral chest wall, if the area of the defect is greater than 100 cm2, chest wall reconstruction is indicated. Moreover, we believe that muscle or myocutaneous flap and/or Marlex mesh in the best way of reconstruct in following chest wall resection.
We have operated 52 cases of chest wall resection in these 20 years. Twenty five cases in it were reconstructed by unabsorbable artificial materials such as Marlex mesh, Gore-Tex sheet and some others (Group 1). Eleven cases were covered with the net knitted by absorbable threads or muscle flaps (Group 2). Resting 16 cases have not received any definitive renovations (Group 3). Group 1 has suffered from such severe postoperative complications as acute empyema (8%) and chronic empyema (8%). Few cases in Group 2 has had infectious complication and ventilatory disturbance. Rate of postoperative vital capacity in Group 3 was the lowest value among three groups, though they had the smallest chest wall defects. We obtained following conclusions from this study. Every chest wall defect should be repaired by some way even if the defect were small. Chest wall defect in compromised host should be repaired by absorbable artificial material and muscle flap. Unabsorbable artificial materials are now indispensable for the reconstruction of large chest wall defect, however we must fully take care of postoperative infections in cases of its use.