Identification of factors affecting the surgical margin in wedge resection using preoperative lipiodol marking

BACKGROUND: The factors affecting the surgical margin distance in resection of small lung lesions after preoperative marking are still unclear. The purpose of this study was to identify these factors in wedge lung resection using a localization technique. METHODS: The subjects were 45 patients with small pulmonary nodules who underwent preoperative computed tomography-guided lipiodol marking followed by video-assisted thoracoscopic surgery between April 2017 and December 2019. Data were obtained for nodule size, depth from the pleural surface, imaging features, and procedure-related factors that could affect the surgical margin. Subjects were divided into groups with margin distances <10 and ≥10 mm. Logistic regression analysis was used to identify factors associated with the margin distance. RESULTS: Preoperative marking was performed using lipiodol prior to resection of 52 nodules (median size, 10.1 mm; range, 6.75–12.3 mm) in 45 patients (23 men, 22 women; median age, 65.4 years). The mean distance from the pleural surface to the pulmonary lesion was 13.8 mm (range, 5.44–22.2 mm). The 3D deviation of the radio-opaque nodule (lipiodol spot) from the lesion was the only significant difference in nodule- and procedure-related factors between the two groups. Multivariate analysis also showed that this 3D deviation was the most significant factor affecting the margin distance (odds ratio, 0.26; 95% CI, 0.08–0.81; P=0.02). CONCLUSIONS: The findings in this study may help to ensure a sufficient surgical margin after preoperative lipiodol marking, through recognition that the 3D deviation of the radio-opaque nodule from the target lesion has a particularly important influence on the margin distance.