A Demonstration of VATS Segmentectomy With Near Infra-Red Imaging Technology
this video the authors present two demonstrations of near infra-red imaging
technology to provide visualisation of pulmonary anatomical segments for
segmentectomy. Pulmonary segments are anatomically and functionally independent
units of the lung, but are macroscopically indistinguishable from other
segments with the naked eye; making their isolated resection difficult.(1) This
technique combines the use of indocyanine green (ICG) a dye that fluoresces in
the near infra-red (NIR) spectrum (800nm) when exposed to light or other
radiation and the Arthex Synergy ID laparoscope; which has a fluorescence
imaging camera system that converts the received NIR information into a visible
image that can be displayed on a monitor.
ICG is water soluble, minimally toxic, and has a low absorption rate in human tissues. It also has a low scatter band and thus can be used to visualise deep tissues. For visualisation of vessels, blood flow and tissue perfusion it is administered intravenously at a dose of 5mg. Visual effects last approximately five minutes whilst is it hepatically metabolised and then excreted faecally. The frequencies of mild, moderate and severe side-effects were only 0.15%, 0.2% and 0.05%; the rate of deaths is 1:333,333.(1)
These procedures demonstrate the utility of this technique in thoracic surgery.
The first patient is a 62 year old female with 12mm slowly enlarging PET avid lower lobe nodule in segment 6 on a background of duodenal cancer resected by whipples procedure 14 months prior. The lesion may have represented a primary lung cancer or a metastasis. We elected to proceed with a segmentectomy and lymphadenectomy.
The segment 6 vein, bronchus and artery were isolated and divided using a Tristapler (Medtronic). This was followed by administration of the recommended dose of ICG intravenously. Demarcation of the targeted segment occurred after about 15 seconds. Segment six of the lung was easily distinguishable from the other body tissues as it did not demonstrate and ICG fluorescence when viewed with the Synergy ID laparoscope as demonstrated in the video. The margin which represented the anatomical segment was then marked via electrocautery to the visceral pleura. The resection was then completed with the Tristapler to divide the segment 6 lung parenchyma. Following the injection of ICG, the visual effects of the ICG lasted about 3 minutes which corroborates previous use in thoracic surgery.(3)
The final histopathology showed that the resected lesion was a primary adeno carcinoma of lung staged pT1bNoR0 (TNM)
The second patient is a 69 year old female with a slow growing left upper lobe lesion within the apex of the left upper lobe. She had recently undergone a right upper lobectomy for T1c adenocarcinoma 3 months prior. The lesion was FDG avid on PET CT. It was uncertain whether it represented a new lung primary or a metastasis. As a result of the chosen method of lung resection was left upper lobe trisegmentectomy to preserve as much lung tissue as possible. The left upper lobe anterior and apico-posterior vein, artery and bronchus were divided. ICG was then administered intravenously resulting in demarcation of the left upper trisegment. The margin was marked with electrocautery and divided with a Tristapler.
The final histology confirmed a 25mm adenocarcinoma T1bNoR0 (TNM) with clear margins.
Near infrared imaging technology is a useful tool to aid anatomical resection during segmentectomy.
Special thanks to Phillip Clark of Athrex Ltd who helped by demonstrating the multiple functions of the Synergy ID laparoscope during both cases.