The Western Thoracic Surgical Association

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Minimally Invasive Segmental Resection with Near-Infrared Fluorescence Imaging: Does It Provide Any Added Value?
Meera Mehta1, Kerri Sullivan1, Yogita Patel1, Kazuhiro Yasufuku2, Thomas Kenneth Waddell2, Yaron Shargall1, Christine Fahim1, WaŽl C Hanna1
1McMaster University, Hamilton, ON, Canada2University of Toronto, Toronto, ON, Canada

Objective: Minimally invasive segmentectomy is a challenging operation. Near-Infrared Fluorescence (NIF) imaging with Indocyanine Green (ICG) dye is reported to facilitate this operation by delineating parenchymal intersegmental planes. However, this novel technique has not been prospectively evaluated. As the demand for segmentectomy rises, we aimed to evaluate the safety, reproducibility, and added margin length achieved by NIF-guided segmentectomy for Stage I non-small cell lung cancer (NSCLC).
Methods: Patients with cT1N0 NSCLC confined to one bronchopulmonary segment were eligible to participate in this Phase I prospective clinical trial. All operations were conducted by Completely Portal Robotic Segmentectomy (CPRS-4). The tumor-containing segment was first isolated from blood supply by division of the segmental vein, artery and bronchus. The "predicted" intersegmental plane was then identified by consensus between two surgeons and marked with cautery (Fig. 1A). ICG (25mg) was then injected in a peripheral vein under NIF. The entire lung was observed to display green fluorescence, except for the excluded segment, which remained dark. The "true" intersegmental plane was then identified as the demarcation line between the fluorescent and dark parenchyma (Fig. 1B). Added margin length was calculated as the mean distance between the "predicted" and "true" intersegmental planes (Fig. 1B). The segment was resected along the "true" plane and the operation concluded if the specimen contained the tumor with clear margins; otherwise, the patient received a completion lobectomy. Each case was evaluated with a pre-defined 7-item binary scale for reproducibility, and was considered successful if it scored 7/7.
Results: Twenty-four (n=24) patients were enrolled between 07/2016 and 07/2017. Median tumor size was 1.6 cm (SD 1.18 cm). Ten patients (10/24, 41.7%) did not receive ICG and proceeded directly to lobectomy (6/24, 25%) or wedge resection (4/24, 16.7%) based on intra-operative decisions. Fourteen patients (14/24, 58.3%) underwent NIF-guidance, with reproducible success in 13/14 (92.9%, score 7/7). One patient (1/14, 7.1%, score 6/7) proceeded to completion lobectomy due to positive tumor margins on intra-operative frozen section. Resections were from the superior (6/14, 42.9%), apical posterior (4/14, 29%), basilar (3/14, 21.5%) and lingular (1/14, 7.1%) segments. The median added margin length attributed to the utilization of NIF imaging was 1.95 cm (range 0-6). Median hospital stay was 3 days (range 1-6). There were no complications greater than Grade II (Clavien-Dindo).
Conclusion: NIF-guided segmentectomy is safe and reproducible. It provides added value by extending margin length on the resected specimen to include segmental parenchyma that would've been missed without NIF imaging. This study generates preliminary data for a subsequent comparative trial.
Figure 1: A. The surgeon marks the "predicted" intersegmental plane with cautery under white light vision. B. NIF-guidance demonstrates the "true" intersegmental plane (black arrows) in contrast with the "predicted" plane (white arrows). The red arrows demonstrate the added margin length that would've been missed without NIF-guidance.


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