Materials and Methods: In 52 patients with peripheral pulmonary nodules smaller than 20 mm, the nodule was marked by injecting 0.5-1 cc methylene blue with the guidance of computed tomography (CT) with a Chiba needle (22 G), before they were taken to the operating room. A frozen section examination was done after wedge resection with VATS.

Results: The mean nodule size in the study was 8.85 mm (3-25 mm). The mean measurement distance to the chest wall at the peripheral endpoint of the nodules was 9.0 mm (1-40 mm). Of the nodules, 22 were solid, 15 were semisolid, and 15 were ground glass. Pathology subtypes were as follows, especially in ground glass lesions whose localization could not be determined without marking; 7 adenocarcinomas, 2 adenocarcinomas in situ, 4 atypical adenomatous hyperplasias, and 2 benign cytology. The pathologies for the other 37 patients resulted in 13 benign cytology, 10 metastases of known malignancy, 3 lung squamous cell carcinoma (pT1bN0, pT1aN1), 7 adenocarcinoma (pT1aN0- pT2N0), 1 adenocarcinoma in situ, 2 typical carcinoids (pT1aN0) and 1 atypical adenomatous hyperplasia.

Conclusions: Through CT-guided percutaneous methylene blue marking, the localization of peripherally located, small-sized, and non-palpable lesions can be detected easily with uVATS. In this way, unnecessary thoracotomy can be avoided, the operation can be performed quickly and with low morbidity, and the diagnosis of lung cancer can be provided at an early stage. Keywords : videothoracoscopic surgery, methylene blue, dye, ground glass nodule, uniportal