A convenient method for identifying a small pulmonary nodule using a dyed swab and geometric mapping

Mitsuhiro Kamiyoshihara, Takashi Ibe, Natsuko Kawatani, Fumi Ohsawa, Ryohei Yoshikawa, Kimihiro Shimizu


Background: Computed tomography (CT)—guided lung needle marking is useful to identify pulmonary nodules. However, certain complications sometimes trigger severe after-effects or death. So, we present a convenient and safe method by which small pulmonary nodules can be identified using a particular dye [2% (w/v) gentian violet].
Methods: A patient is initially placed in the lateral operative position. Under CT guidance, a “magic marker” is used to identify the skin above the pulmonary nodule. During the operation, the chest wall is punctured on that mark using a needle loop retractor (Mini Loop Retractor II). A swab saturated in the dye solution is attached to a silk thread and passed through the loop. The loop and string are subsequently retracted. The dye-stamp is apparent on the lung surface above the nodule after the lung is inflated. If the scapula, any vertebra, or the clavicle compromised access to a nodule, we used our geometric technique to locate that nodule.
Results: We used this technique to treat 51 lesions of 50 patients presenting from 2013 to 2015. Mean tumor diameter was 7 mm. All lesions were identified via thoracoscopy, all nodules were constrained by ring forceps, and wedge resections were performed using a stapler. All lesions lay very close to the staple markings, as judged by finger or instrument palpation. No complications were encountered.
Conclusions: The advantages of our technique are that it is simple and easy, air emboli are not an issue, the skin marking is rapid, safety is assured, and the skin marking does not require hospitalization. Our method is also useful such as following situations; it defines the margins of the cut line upon anatomical segmentectomy, indicates where a skin incision is required, and identifies impalpable nodules, which aids the lung resection but provides frozen sections to the pathologist.