The Use Of Computer-assisted Surgery System In The Thoracoscopic Surgery

Objective Although thoracoscopic surgery has become an important tool in clinical routine, the shortages are obvious. Thoracoscopy has limits in the detection of small pulmonary nodules,which are invisible and/or impalpable during surgery. Methods to localize such lesions,including the methylene blue injection or the introduction of a hooked-wire under the guidance of CT,have some limitations. The thoracoscope only provides a surface view of an organs, the surgeon has lost the depth information provided by the third dimension in real world. As a result, the anatomical dissection of the hilum in an essentially closed chest immediately begged the question of safety. There is a need for more advanced visualizations techniques that can enhance the thoracscopic display presented to the surgeon so that important information below the surface of the organs is included when planning the procedure as well as for guidance and control during treatment. Recent advances in Image Guided Surgery (IGS) have been brought about by the development of computer technology to make the minimally invasive techniques safer and more accurate. The primary advantage of Image Guided Surgery is that it provides the surgeon with accurate knowledge of the spatial relationship between the surgical instrument or appliance and the surrounding structures not directly visible in the operative field. We are developing a new technique using image-guided navigation system for localization of small pulmonary nodules before thoracoscopic surgery. To overcome the technical difficulties inherent to thoracoscopic major pulmonary resections and the fear of possible intraoperative complications, we have also developed computer graphics-based methods introduced in this paper of integration of video thoracoscopic images with preoperative 3-D CT volumes rendering, for assistance in the planning and guidance of surgical procedures. The study included two parts:Part one: Methods In animal group, four dogs were spiral-computed tomography (CT) scanned after given percutaneously created pulmonary lesions. The CT data were transmitted to StealthStation navigation system. With the help of the probe the lesions were located and resected under thoracoscopy. In the clinical group, the CT data of a patient who had a peripheral small pulmonary nodule (SPN) < 20 mm in size were transmitted to the StealthStation navigation system. To match the position of the probe with the CT scan, 5 to 6 superficial skin fiducials were used for registration. Real-time, multiplanar reconstruction of a previously acquired CT data set provided three-dimensional views for localization of the SPN. With the help of the probe the lesions were localized and resected under thoracoscopy. Results Total 20 lesions were created in the animal group. Nodules were located at an average distance of 11.6 mm from the pleural surface. All the lesions were successfully localized. Biopsy specimens revealed successful resection of target material. Eight patients (5 men and 3 women) underwent this procedure and all the nodules were identified due to the precise location of the probe. They were resected with sufficient margins. There were no surgical complications. Conclusions Image guided navigation is useful, accurate, and safe in the localization of peripheral lung lesions.Part two: Method The 3D-CT pulmonary angiography of 10 fresh pig lungs were obtained using multidetector row spiral CT. Then all the lungs were divided into two groups, A and B group. In A group,5 lungs received thoracoscopic right lower pulmonary artery dissection under Stealthstation Computer-assisted Navigational Surgery system. In B group,the other 5 lungs underwent conventional thoracoscopic pulmonary artery dissection. Result The time of the operation was 29.8±8.1min in group A and was 49.4±8.8min (p<0.003) in group B. There were no unexpected rupture of pulmonary artery in group A, but in group B there was one. Conclusion The Computer-assisted Navigational Surgery system was a useful tool for image guidance in thoracoscopic surgery, both for planning the surgical approach in detail and for guidance. The new technology could increase safety and make it easier for the surgeon to perform successful thoracoscopic surgery.