Tetsuya Akagawa

Use of a laser-hardened three-dimensional replica for simulated surgery

The main established approaches to preoperative surgical planning for mandibular reconstruction and correction of jaw deformities have been paper simulations using radiographic images and profile photographs of the head, and plaster model simulations of the teeth and jaws. However, these do not always provide sufficient information, especially in patients with an asymmetry. Three-dimensional images generated from computerized tomographic (CT) scans have the advantage of providing the ability to simulate the operation as well as repositioning of bones on the computer screen. Accumulated experience in cases with complicated features however, has shown that the images on the monitor often do not show the preoperative structure sufficiently accurately. The inability to perform simulated surgery exactly as in the actual operation has also proven to be a 1imitation.“5 Recently a new system for performing simulated surgery using solid replicas generated from the threedimensional computer images has been deve10ped.6-s We have been participating in this work, and have produced numerous replicas of the maxillofacial bones, which have been investigated extensively. In this article, we describe the method of simulating surgery using three-dimensional replicas and demonstrate the procedure in two patients; one with a jaw deformity treated by simultaneous maxillary advancement and mandibular retrusion, and one who required mandibular reconstruction after resection of a tumor.

A new, rolled-sponge technique for transoral exposure of C1 and C2.

Instead of the general use of a catheter attached to the uvula or of catheters passed through the nasal cavity to the mouth for elevation of soft palate, the authors describe a new technique utilizing two rolled sponges producing maximum elevation of soft palate and good perioral cosmetic results for transoral exposure of C1 and C2.

Controlled release of adriamycin from silicon.

We have developed a prolonged release preparation of adriamycin with silicon as a carrier for use in localized chemotherapy of recurrent and metastatic cancer and in embolism chemotherapy of primary cancer. In the present study, we observed the temperature sensitivity of the drug release and tissue degeneration due to embedding in the muscle and tumor tissue in this system, and investigated the antitumor effects using cancer bearing rats, The results indicated that the drug release increased about two-fold when the temperature was changed from 37 to 43°C, and there was a marked improvement in component drug release efficiency when glycine was added in place of the silicon. When the prolonged-release preparation of adriamycin was embedded in the muscle tissue, degeneration of the surrounding tissue increased with the increase in the dose of the drug, There was also tissue degeneration associated with necrosis in the rapidly growing tumor tissue, and the drug showed continuous action. In the experiment using tumor-bearing rats, all of the tumors died within 10 days with an average survival period of 8.5±1.3 days after bearing the cancer in the control group, and an average survival period of at least 46.8 days, with 40% surviving for 60 days, in the group given the timerelease preparation. The prolonged release preparation showd marked life extending effects.