Shogo Toda

Lung metastasis of thymoma manifesting as myasthenia gravis 12 years after thymomectomy: report of a case.

A 51-year-old woman, who had undergone thymomectomy for asymptomatic noninvasive thymoma 12 years before, was admitted to our hospital with blepharoptosis caused by myasthenia gravis. A chest computed tomogram (CT) showed an abnormal shadow in the right lower lung field and CT-guided needle biopsy revealed findings of a thymoma. We performed extended thymectomy and partial resection of the right lung using three different approaches, via a cervical incision and bilateral video-assisted thoracoscopic surgery. The resected specimen was a lung metastasis of thymoma, and the residual mediastinal tissue showed no sign of malignancy. Because thymoma and post-thymomectomy myasthenia gravis can both recur, we recommend performing extended thymectomy or thymothymectomy, even for patients who are asymptomatic.

Venovenous extracorporeal membrane oxygenation support for treatment of bilateral spontaneous pneumothorax

Bilateral spontaneous pneumothorax is a rare but serious cause of respiratory distress. We treated a 77-year-old male with severe hypoxia caused by bilateral spontaneous pneumothorax using video-assisted thoracoscopic bullectomy assisted by a venovenous extracorporeal membrane oxygenation (ECMO) device. The patient came to the emergency department of our hospital with complaints of cough and dyspnea, and was hospitalized with right-side spontaneous pneumothorax and left-side pneumonia. After 12 days, a chest radiograph was performed to investigate persistent progressive shortness of breath at rest, which demonstrated contralateral pneumothorax. A chest tube was inserted into the left pleural cavity, and surgery was performed for bilateral pneumothorax by video-assisted thoracoscopic surgery (VATS) assisted by venovenous ECMO. Gas exchange was satisfactory throughout the surgical procedure and the postoperative course was uneventful without complications. Venovenous ECMO was effective for facilitation of VATS and reduced the risk of an intra-operative hypoxic condition.

Extrapericardial Pulmonary Vein Clamp Technique for Pulmonary Arteriovenous Fistula: Report of a Case

The major concern when operating on a patient with a neurologically symptomatic pulmonary arteriovenous fistula (PAVF) is how to prevent a thromboembolic event during surgery. We describe a new technique whereby the extrapericardial pulmonary vein is clamped before transecting the afferent and efferent vessels of the fistula. The potentially pooled clots that can form while manipulating lung are stopped by the clamp. Before the extrapericardial pulmonary vein is declamped, one of the drainage veins is incised halfway and the pooled blood containing the potential clots is completely washed out. We successfully performed segmentectomy using this technique in a 66-year-old man with chronic left hemianopia and a large PAVF in the left anteromedial and lateral basal segments, and no thromboembolic events occurred.

A pulsatile pump for cardiopulmonary bypass and its clinical use

A pulsatile pump driven by a coil spring, which was designed and constructed by us, is described in this report. It consists of two main parts, a disposable blood chamber and a driving section. The blood chamber has two leaflet valves and a piston, which is covered with two bellofram rolling diaphragms and moves into the housing to draw in and eject the blood. The driving section consists of three cams, an electric motor and a coil spring. The ejection force is wholly produced by the compressed coil spring and is transmitted to the piston in the blood chamber by a rod. This pump allows the ejection pressure, the beat rates, and the stroke volume all to be changed independently. The performance of the pump was tested by using a circulation model where the beat rate was adjusted from 30 to 250 bpm. The output subsequently increased from 0.81/min to 5.71/min and the stroke volume, from 20.4 ml to 36.7 ml. This new pump has been used for clinical cardiopulmonary bypasses in 24 patients of open heart surgery and the pressure traces during perfusion resembled those of the patients’ own hearts.