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Background: The pulmonary nodules have become the major indication of video-assisted thoracic surgery (VATS). Recently, several preoperative or intraoperative techniques for identifying small or deeply seated pulmonary nodules have facilitated thoracoscopic resection. We describe the new technique for detecting difficult lesions., Methods: Preoperatively, we marked the visceral pleura near the pulmonary nodules with dye, simultaneously injected contrast media (1 water-soluble Optiray [Mallinckrodt Medical Inc, Quebec, Canada], 18 barium sulfate, 11 Lipiodol [Laboratoire Guerbet, Aulnay-sous-Bois, France]) into or around the nodule under computed tomography (CT) guidance. During VATS, we were able to easily and accurately detect and resect all the nodules localized with contrast media, of which the radiopacity was visualized on the portable fluoroscopic monitor., Results: Between February 1996 and December 1998, we thoracoscopically resected 30 nodules in 28 patients (13 were women; age, 53 +/- 14 years). The resected nodules were 17 +/- 7.6 mm (range; 4 to 32 mm) in size, and 8.9 +/- 8 mm (range, 2 to 34 mm) in depth. The pathologic diagnosis of the nodules was benign in 20 and malignant in 10 (six primary cancers of lung and four metastatic cancers). There were only minor complications related CT localization., Conclusions: This new technique can help the surgeons detect and resect the difficult lesions with safety and rapidity by VATS without thoracotomy.

The purpose of this study was to evaluate the stress distributions of fixed partial dentures with secondary abutments. In the case where the lower first premolar and the second premolar were missing, four 2-dimensional photoelastic models with the canine and the first molar as primary abutments with secondary abutments were prepared as follows; Model I: primary abutments only. Model II: primary abutments with the lateral incisor as the secondary abutment. Model III: primary abutments with the second molar as the secondary abutment. Model IV: primary abutments with the lateral incisor and the second molar as secondary abutments. Two-dimensional photoelastic stress analysis was used with the stress areas recorded photographically. A vertical load was applied to the pontic in each case. After the stress patterns in surrounding tissues of the abutments were observed and recorded, the conclusions were as follows: 1. In model I, applied force was distributed to the long axis of the abutments. 2. In model II, III, IV, all the secondary abutments showed compressive stresses. No tensile stresses were developed. 3. The mesial aspect of the lateral incisor and the distal aspect of the second molar as the secondary abutment showed no compressive stresses.

The purpose of this study was to evaluate the stress distributions to the abutments of a fixed partial denture with tilted molar abutments. In cases of the lower 1st molar being missing four 2-dimensional photoelastic models with 3- unit fixed partial dentures of which the 2nd molars were tilted 0 degrees, 10 degrees, 20 degrees and 30 degrees toward the 2nd premolar were made. A vertical load of 50 lbs was applied to the 1st and 2nd molar in each case. Two-dimensional photoelastic stress analysis was used, and the stress areas were recorded photographically. The results were as follows; 1. When the vertical load was applied to pontic and 2nd molar on the central fossae, the magnitude of stress distribution of the surrounding tissues of the root of the 2nd premolar was increased incrementally with increasing inclination. 2. Under two loading conditions, the stress distributions were directed to the long axis of the abutments. 3. In this experiment, no stress distributions were observed on the mesial area of the mesial root of the second molar.