Thoracoscopic small pulmonary nodule detection using computed tomography-guided cutaneous marking and pleural marking

Intrathoracic use of a small ultrasonic probe for localizing small lung tumors in thoracoscopic surgery: Empirical results and comparison with preoperative CT images

OBJECTIVE

To evaluate the use of a small mobile ultrasound probe to localize small lung tumors during thoracoscopic surgery under thoracic CO₂ insufflation.

METHODS

We prospectively enrolled 20 patients (26 tumors) scheduled to undergo thoracoscopic pulmonary wedge resection between April 2016 and October 2018. Ultrasonographic tumor detection was performed with an ARIETTA 850 and L51K probe (Hitachi, Tokyo, Japan). Ultrasonography was repeated after achieving adequate lung collapse under a positive intrathoracic pressure of 8-15 mmHg. The appearance on preoperative CT versus the ultrasonographic localization was compared for each tumor. The receiver operating characteristic curves were compared for the tumor dimension of the lung window, consolidation dimension of the lung window, tumor dimension of the mediastinal window (MD), and tumor depth from the lung surface.

RESULTS

The average age was 62 years (range 42-79 years), average pathological tumor size was 9 mm (range 3-22 mm), and average tumor depth was 6 mm (range 1-25 mm). Although no tumors could be visualized before lung collapse, 22 tumors (85%) were detectable with ultrasonography after lung collapse. Of these 22 tumors, 16 were well-depicted, while six were poorly delineated. MD showed the largest area under the receiver operating characteristic curve (0.81), and tumors with a MD of ≤ 6 mm had a high risk of difficult localization using ultrasonography.

CONCLUSION

This ultrasonographic method obtained high tumor detection rates, especially for tumors with a MD > 6 mm. Tumors with a MD ≤ 6 mm may require another localization method.

CLINICAL REGISTRATION NUMBER

University Hospital Medical Information Network Clinical Trials Registry (UMIN000036921).

Virtual thoracoscopic imaging-assisted pleural marking of pulmonary nodules

Background

Computed tomography (CT) is now able to detect small pulmonary nodules. Surgical resection for diagnosis of these nodules is widely performed with video-assisted thoracoscopic surgery (VATS). However, it is very difficult to localize a small tumor by palpation via a small access port. In this study, we aimed to describe a novel intraoperative method for marking the location of the pulmonary nodule.

Methods

In 46 cases, a virtual thoracoscopic image was reconstructed using the CT images of the chest using volume rendering software before surgery. During thoracoscopic surgery, a pleural marker was affixed to the parietal pleura, just above the tumor, by referring to the virtual thoracoscopic image. The pleural marker dye was then transferred to the point on the visceral pleura just above the nodule. The distance between the center of the marking and the visceral pleura closest to the tumor was measured to evaluate the accuracy of the marking.

Results

The mean distance between the center of the marking and the visceral pleura closest to the tumor was 10.2 mm. In 42 cases (92%), the tumor was within 30 mm of the marked point. All tumors were fully resected. No morbidity occurred intra- or postoperatively.

Conclusions

Our pleural marking, using a virtual thoracoscopic image, identified the tumor location with high accuracy, may help surgeon to confirm whether the palpated nodule is the target one. This new procedure can assist in the localization of the pulmonary nodule with ease of application, safety, and accuracy.