Pulmonary function after thoracoscopic thymectomy versus median sternotomy for myasthenia gravis

Background. Impaired pulmonary function due to myasthenia gravis (MG) is further compromised by thymectomy, which is necessary in most cases. Thoracoscopic thymectomy (tThx) can achieve the same resection and functional improvement of MG as median sternotomy (sThx). The possible advantage of tThx in maintaining better perioperative lung function was quantified. Methods. In a prospective trial, 20 patients with MG were randomly allocated to undergo tThx (n = 10) by three-trocar left-sided approach or sThx (n = 10) performed as an extended procedure. Complete pulmonary function was measured at 12-hour intervals, beginning 6 hours postoperatively. Effective postoperative pain control in both groups was achieved by patient-controlled analgesia with morphine sulfate assessed by a visual analogue scale. Statistical analysis for comparison of tThx and sThx was performed using the Mann-Whitney U test. Results. postoperative vital capacity, forced vital capacity, forced expiratory volume per second, and peak expiratory flow, measured as a percentage of the individual preoperative capacity, were significantly better with tThx compared with sThx. Immediate postoperative lung function was reduced to 35% and 65% after tThx and sThx, respectively. By the third postoperative day, recovery of pulmonary function was complete after tThx but only 55% after sThx. Conclusions. Less pronounced impairment and faster recovery of pulmonary function after tThx characterize this new approach for thymectomy as minimally invasive. These results could make tThx the preferred surgical treatment of MG, which was improved to the same extent as after sThx. (Ann Thorac Surg 2000;70:1656-61) (C) 2000 by The Society of Thoracic Surgeons.