Small pulmonary nodule localization with cone beam computed tomography during video-assisted thoracic surgery: a feasibility study.

Objectives: To describe a non-invasive guidance procedure, using intraoperative cone beam computed tomography (CBCT) and augmented fluoroscopy to guide lung resection during video-assisted thoracic surgery (VATS).

Methods: Patients with solitary or multiple lung nodules between 5 and 20 mm in size were included. Under general anaesthesia, a moderate pneumothorax allowing the CBCT acquisition was first performed. Then a segmentation of the lesion was performed on a 3D reconstruction. A projection of this 3D reconstruction was then integrated into the digital workspace and automatically registered into the fluoroscopic images, creating an augmented fluoroscopy. The procedure was continued under classic video-thoracoscopic vision taking account of the augmented fluoroscopy to locate the targeted nodule.

Results: Eight patients were included (mean age 61 ± 11.7 years): 7 patients had an isolated lesion and 1 patient had two lesions (mean size 13.2 ± 5.1 mm). Their mean depth to the pleura was 21.4 ± 10.7 mm. Four patients underwent a wedge resection associated with lymph node resection. Two patients had an initial wedge resection followed by a complementary lobectomy associated with lymph node resection (primary lung tumour). One patient had a wedge resection in the upper lobe and a lobectomy of the inferior lobe associated with lymph node resection. One patient underwent a conversion and a bilobectomy due to vascular injury. The mean global operating time was 100.6 ± 36.7 min. All the nodules have been identified on the CBCT acquisitions. The segmentation of the lesion has been performed in all cases. We have been able to detect all the nodules and to successfully perform the resection in all cases owing to the augmented fluoroscopy. The mean fluoroscopic time was 134.2 ± 55.0 s. The mean imaging time, between the incision and the final nodule localization, was 11.8 ± 3.8 min.

Conclusions: This paper is the first describing a clinical application of CBCT performed during thoracic surgery. Associated with augmented reality, it offers a significant progress in VATS resection of subpalpable lung nodules. This preliminary experience highlights the potential of the proposed CBCT approach to improve the perception of targeted small tumours during VATS.