National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran TANAFFOS (Respiration) 1735-0344 3 4(autumn) 2004 12 01 Role of VATS in Pleural Effusions with Unknown Etiology 25 33 241484 EN Mohammad Behgam Shadmehr Department of Thoracic Surgery, NRITLD, Shaheed Beheshti University of Medical Sciences and Health Services, TEHRAN-IRAN. Mehrdad Arab Department of Thoracic Surgery, NRITLD, Shaheed Beheshti University of Medical Sciences and Health Services, TEHRAN-IRAN. Azizollah Abassi Dezfouli Department of Thoracic Surgery, NRITLD, Shaheed Beheshti University of Medical Sciences and Health Services, TEHRAN-IRAN. Mohammad Keshoofi Department of Thoracic Surgery, NRITLD, Shaheed Beheshti University of Medical Sciences and Health Services, TEHRAN-IRAN. Mohammad Reza Amjadi Department of Thoracic Surgery, NRITLD, Shaheed Beheshti University of Medical Sciences and Health Services, TEHRAN-IRAN. Roya Farzanegan Department of Thoracic Surgery, NRITLD, Shaheed Beheshti University of Medical Sciences and Health Services, TEHRAN-IRAN. Nahid Jahanshahi Department of Thoracic Surgery, NRITLD, Shaheed Beheshti University of Medical Sciences and Health Services, TEHRAN-IRAN. Journal Article 2021 01 06 Background: The cause of pleural effusion in some patients can not be found even after biochemical, bacteriologic and cytological examinations of the pleural fluid and closed needle biopsy of the pleura. In this group of patients the next diagnostic step would be an open pleural biopsy through a limited thoracotomy or video-assisted thoracoscopic surgery (VATS), the latter procedure has replaced the former in many centers due to its advantages. Materials and Methods: In order to evaluate these advantages, 59 patients with undiagnosed pleural effusion were operated on through either limited thoracotomy or thoracoscopy form April 1998 to September 2000, in a prospective clinical trial. There were 40 males and 19 females in the age range of 10 to 89 yrs. There was no significant statistical difference between the two groups in terms of sex and age. Results: There was no statistical difference between the two groups in terms of diagnostic accuracy, postoperative pain, hospitalization, morbidity and mortality. Conclusion: Based on these results and minimal scar, VATS is a safe diagnostic procedure in this group of patients replacing limited thoracotomy. (Tanaffos 2004; 3(12): 25-33) https://www.tanaffosjournal.ir/article_241484_39a824ae4dfe9077e4f5ab6c4d37b5db.pdf