The application of this new technique was approved by the institutional review board at Nanjing Chest Hospital, all patients provided written informed consent before operation.
Patients considered appropriate for this technique met the following criteria: age 18–65, preoperative diagnosis of thymoma with Myasthenia Gravis Foundation of America(MGFA) class I-II, American Society of Anaesthesiologists(ASA) grade of I-II, masaoka stage I-II with maximal diameter < 5cm. Patients with a bleeding disorder, overweight(BMI > 28), pulmonary insufficiency, history of chest surgery and potential difficult airway for intubation were not considered suitable.
Patient was kept in lithotomy position. The anaesthesia protocol was previously reported(2). In brief, after intravenous infusion of dexmedetomidine 1ug/kg by pump injection (completed within 15min), anesthesia was induced with intravenous dexamethasone 10.00mg, midazolam 0.10 mg/kg and sufentanil 0.1–0.2 µg/kg, with the target-controlled infusion (TCI) of propofol (target plasma concentration of 2–3µg/ml). To keep oxygen saturation above 95%, pre-lubricated laryngeal mask was inserted for spontaneous ventilation with 100% inspired oxygen (4–5 L/min). Skin infiltration was performed at operation site with 0.375% ropivacaine and 1.00% lidocaine. Maintainance of anesthesia was done with TCI of propofol (target plasma concentration of 1–2µg/ml), dexmedetomidine(0.5-1µg/kg/h) and remifentanil(0.1 ~ 0.5ug/kg/h). We used train-of-four (TOF) monitoring during surgery and ensured full recovery prior to terminating the anesthetics. BIS monitoring was maintained at 40–60 during the operation.
A single 3-cm transverse incision was made below the xiphoid process. The retrosternal space was opened by blind blunt dissection. Plastic wound protector was used. A gradual and natural collapse of the lung occurred after opening pleural cavity.
During operation, a 10-mm 30-degree thoracoscope and several thoracoscopic instruments could be simultaneously fitted into the uni-port. A sternum retractor would be placed at the incision cite to raise the sternum about 2cm and facilitate surgical maneuvers(Fig. 1).
Both side of mediastinal pleura should be opened till internal thoracic vessels. When lower edge of the thymus and the connecting pericardial fat was visualized, a thymectomy was started at the level of the diaphragm and proceeded gradually in an upward direction. Phrenic nerve should be identified and carefully protected. Thymic veins were ligated using ultrasonic scalpe, electric cautery or an appropriately sized clip, then the upper horns of the thymus was isolated. Dissection was continued above the innominate vein to fossa suprasternalis, radical removal of the tumor and the entire thymus gland, including perithymic fatty tissue between both phrenic nerves, from cardiophrenic angles inferiorly to the lower cervical region superiorly was accomplished to achieve an extended thymectomy(Fig. 2). Lymph nodes in anterior mediatinum was sampled. Specimen was placed into a bag and removed through the incision protector.
At the end of the operation, A single-lumen central venous catheter (7Fr, 20cm) was inserted in each side of thoracic cavity at the end of the operation. All patients were transferred to the post anaesthesia care unit for recovery.