This was a case of multiple metachronous carcinomas of the right lung complicated by left diaphragmatic eventration. The decision of which treatment methods to employ in this case was difficult because there were no similar case reports based on our literature search.
The treatment strategies for multiple lung tumors depend on the physical status of the patient. Surgical resections are considered if patients are expected to have sufficient physical functions following resection. An aggressive surgical approach has been reported as a safe and justified method for most patients with multiple primary lung cancers [2]. The selection of surgical methods is important for resection. In our case, the CT image showed that the right S9 tumor was 21 mm, solid, and near a bulla. We chose a segmentectomy for the right S9 tumor because these characteristics suggested the possibility of high-grade malignancy.
When evaluating the preoperative status of patients, preoperative physiologic assessments are important [3]. In cases where both % predicted postoperative (ppo)-FEV1 and %ppo-diffusing capacity of the lungs for carbon monoxide (DLCO) values are less than 60%, the patient is considered to have a high risk for complications following anatomic lung resection [4]. In our case, the initial %FEV1 was 58.6%, and we thought the patient had a high risk for pulmonary resection. We nearly abandoned surgical treatment because of her poor pulmonary function; however, we suspected that her poor pulmonary function was caused by the left diaphragmatic eventration and considered performing diaphragm plication to possibly improve her respiratory function. Her pulmonary function improved after diaphragm plication; therefore, this strategy was successful and effective.
Diaphragmatic elevation is a condition caused by phrenic nerve injury or congenital diaphragm eventration. The indications for diaphragm plication are usually dyspnea with low pulmonary function. Diaphragm plication is a well-established surgical procedure that substantially improves dyspnea and objective measures of pulmonary function in patients who are symptomatic from diaphragm paralysis or eventration [5,6,7]. Diaphragm plication is a safe and effective procedure for adult patients with dyspnea due to unilateral diaphragmatic paralysis [5]. In our case, the patient had mild difficulty breathing. Furthermore, the improvement of her pulmonary function was necessary to safely perform the contralateral lung resection. In symptomatic patients with unilateral diaphragm paralysis, global inspiratory strength is reduced due not only to weakness in the paralyzed hemidiaphragm but also to impairment in the pressure generated by the non-paralyzed hemidiaphragm [8]. In our case, unilateral diaphragm plication might have influenced the contralateral diaphragm movement.
In our case, we needed a minimally invasive surgical technique to treat the diaphragmatic eventration and perform the operation for the contralateral lung carcinomas. We selected VATS with CO2 insufflation due to the reduced risk of morbidity compared to that associated with open thoracotomy. The fact that thoracotomy itself is known to reduce diaphragm function transiently [9, 10] and that this deficit recovers more quickly after VATS than after thoracotomy [11] is important when selecting a procedure. Using CO2 insufflation for thoracoscopic plication was effective, and VATS with CO2 insufflation is becoming common. CO2 gas insufflation provided excellent working space and made the stitching easy until the diaphragm was nearly flat [12]. The simplicity of this operation may be safe and is associated with a low risk of morbidity for patients. There is a possibility that the intrathoracic pressure can become too high, but low-pressure insufflation up to 10 mmHg produced no deleterious effects on the patient’s hemodynamic status [13].