７．縦隔疾患に対する低侵襲手術：１） 胸腺疾患に対する手技と治療成績

We retrospective reviewed minimally invasive video-assisted thoracoscopic surgery(VATS)tothymic diseases. These procedures were performed using intercostal and infrasternal approachwith a sternum-elevator. Indications of this method are benign thymic lesions［mature teratoma,thymic cyst and myasthenia gravis (MG)］and small thymoma (non-invasive MasaokastageⅠ-Ⅱ, less than 5cm in diameter and nontouching to the left brachiocephalic vein). Fiftypatients underwent VATS for 13 hemithymectomies (7 thymomas, 5 mature teratomas and 1thymic cyst) and 37 extended thymectomies (25 nonthymomatous MGs and 12 thymomatousMGs). Conversion to sternotomy was required in 3 cases of nonthymomatous MG because ofbleeding from thymic vein in 1case and pleural adhesion in 2cases. Four cases of thymomatousMG were successfully treated with partial lung resection and/or small pericardial resection byVATS. New bipolar vessel sealing system (LigaSure V)is safer and more useful than metal clipand ultrasonic coagulator in VATS for thymic vein sealing, extraction of upper poles of thymusand incision of mediastinal pleura near phrenic nerve. VATS thymectomy should be useful fromthe standpoint of less invasive, less pain, rapid recovery, and good cosmetic results.