Effect of patient position during virtual-assisted lung mapping.

Background: Virtual-assisted lung mapping (VAL-MAP) is a preoperative multi-spot bronchoscopic dye-marking technique. Marking failure reportedly occurs in approximately 10% of marks. The aim of the present study was to investigate whether the patient position during dye injection in VAL-MAP affected the quality of markings.
Methods: This study was a retrospective review of patients with barely palpable pulmonary nodules who underwent VAL-MAP at a single institution between December 2016 and September 2017. Easily visible markings without bulla formation were defined as "appropriate", while other markings were defined as "inappropriate". Patients were divided in accordance with the position during dye injection into the supine position group (n=6) and the lateral position group (n=8). The two groups were compared regarding the appropriate markings rate. The Fisher exact test and logistic regression model were used for statistical analyses.
Results: Fourteen patients with 17 nodules underwent VAL-MAP with a total of 48 markings (3.4±0.9 markings per patient). Of these, 21 markings were performed in supine position, whereas 27 were performed in lateral position. There were no significant differences between the two groups in lesion size, depth, and characteristics. Almost all of the performed procedures were thoracoscopic wedge resections (94%), while one procedure was thoracoscopic left upper division segmentectomy. The appropriate markings rate was significantly greater in the lateral position group than in the supine position group (88% vs. 57%, P=0.02). Among the markings located in dorsal and ventral lung segments, the appropriate markings rate in the lateral position group tended to be greater than that in the supine position group (89% vs. 59%, P=0.06). Multivariate logistic regression analysis revealed that the lateral position was independently associated with appropriate markings (P=0.014).
Conclusions: The lateral position may enable the creation of better quality markings in VAL-MAP.
Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.