New tactile sensor techniques for localization of pulmonary nodules

We developed a new method for thoracoscopically localizing pulmonary nodules using a tactile sensor. This sensor was originally designed to probe the hardness of an object, which is represented by changes in resonance frequency of the sensor (delta f: Hz). By moving over the lung surface, the sensor probe, introduced through a 10 mm trocar, was able to search for nodules within the pulmonary parenchyma thoracoscopically. When the sensor probe passed just above a nodule, which was harder than the adjacent tissue, a sudden sharp increase in the curve was observed. We have successfully utilized this method in 16 cases since August 1994. A representative case is that of a 68-year-old male who was admitted with an indeterminate nodule, demonstrated preoperatively in the left lung by chest computed tomography, which was localized with this technique and resected under thoracoscopic surgery.