Double indocyanine green technique of robotic right colectomy: Introduction of a new technique.

In robotic right hemicolectomy for colorectal cancer (CRC), appropriate lymphadenectomy and anastomotic leak prevention are critical. Visualisation of lymph nodes and blood flow with near-infrared (NIR) fluorescence DaVinci® imaging system is a recent development. Herein, we present an improved robotic modified complete mesocolic excision (mCME) technique using indocyanine green (ICG) fluorescence. Before surgery, ICG is injected into the submucosa around the tumour with endoscopy for intraoperative detection of lymph nodes. Robotic mCME with central vascular ligation is performed, supplemented in most of the cases with selective extended lymphadenectomy. Intestinal blood flow before anastomosis is evaluated by administering ICG intravenously and NIR visualisation. Visualisation of the lymph nodes with ICG facilitates standard mCME lymphadenectomy and enables extended lymphadenectomy. Blood flow of the intestinal walls of the anastomotic site can be assessed and determines the extent of intestinal resection. Robotic double ICG technique for robotic right hemicolectomy enables improved lymphadenectomy and warrants the extent of intestinal resection; thus, becoming a strong candidate for gold standard in robotic resections of the right colon for CRC.

INTRODUCTION

Complete mesocolic excision (CME) with central vascular ligation (CVL) was first described by Hohenberger et al.[1] and Bokey et al.[2] The technique involves dissection of the entire mesocolon between the embryonic planes.[3] Patient outcomes show that compared to previously performed procedures, CME reduces local recurrence from 6.5% to 3.6%[1] and shows improved survival rates, especially for Stage 3 patients (27% of survival advantage at 5 years).[4] Subsequent studies have proved the feasibility and safety of the CME technique in both open and MI right colon surgery, with promising long-term oncologic outcomes.[56] Since 1997, we have routinely performed open and MI right colectomies for cancer with radical lymphadenectomy and CVL using a technique recently described as ‘modified CME’ (mCME).[7] In a recently published series of 100 cases of robotic right colectomy using mCME and intracorporeal anastomosis for right-sided colon cancer during a median follow-up period of 48.5 months, the survival rates were 94.5% for disease-specific survival, 91.4% for disease-free survival and 90.3% for overall survival.[8] Thus, proving the feasibility and safety of robotic mCME for the treatment of right-sided colon cancer.

Firefly technology embodied in the Vinci Xi® system offers to make surgical performance even safer and easier. Intraoperative indocyanine green (ICG) fluorescence can provide valuable information translating into the patients’ benefits. Herein, we present an improved technique of robotic mCME with double ICG fluorescence administration routinely used in our institution since 2016. The technique has so far been used in over 50 patients. Evaluation of long-term oncological benefits is warranted.

PATIENTS/MATERIALS AND METHODS

Patients with right-sided colorectal cancer (CRC) undergo standard pre-operative workup and preparation. This includes on day before the surgery, an endoscopic blue dye injection in the submucosa around the tumour for intraoperative tumour localisation in the white light. In addition, a total of 6 ml of an ICG solution (3 mg) is injected endoscopically into four spots around the tumour in the submucosa for intraoperative lymph node mapping with near-infrared (NIR) fluorescence DaVinci® imaging system. A robotic right hemicolectomy is carried out according to robotic mCME with CVL as previously described by our team.[8] Tumour localisation is based on blue dye identification in white light enhanced by NIR fluorescence of ICG. The lymph nodes are removed en bloc by a standard lymphadenectomy; however, they are removed with the ‘berry-picking’ technique when detected with ICG fluorescence outside standard lymphadenectomy area (right gastroepiploic LN, pancreatic head LN and around left branches of SMA) [Figure 1e and f]. With robotic ICG system, the lymph nodes and lymph vessels that contain ICG appear as shining fluorescent spots and streams in the fluorescence image [Figure 1b, d and f]. Subsequently, ICG is intraoperatively administered intravenously (mean of 3.0 mL [range 2–4 mL] ICG solution [2.5 mg/mL]) to objectively assess colon perfusion before bowel anastomosis. After a short time (approximately 30–60 s), perfusion to the colon and terminal ileum is visually confirmed with NIR fluorescence DaVinci® imaging system [Figure 2a and b]. In cases of malperfusion, the resection is extended. Facultatively, intravenous ICG administration can be performed during/after the creation of stapled anastomosis to confirm adequate perfusion of the anastomosis [Figure 2c and d].

Figure 1

Visualisation of lymph nodes and vessels with indocyanine green injected into pre-operative endoscopy (a and b) Anterior view of the mesocolon (c and d) Posterior view of the mesocolon (e and f) Lymph node outside (to the left) of the resection margin. Left: White light view, Right: Near-infrared light view

Figure 2

Visualisation of blood supply to the terminal ileum and transverse colon after intraoperative intravenous injection of indocyanine green (a and b) Before anastomosis (c and d) During anastomosis. Left: White light view, Right: Near-infrared light view

RESULTS

The presented technique is feasible and safe. Visualisation of the lymph nodes with ICG facilitates standard mCME lymphadenectomy and enables extended lymphadenectomy. Blood flow of the intestinal walls of the anastomotic site can be assessed and determines the extent of intestinal resection. Therefore, it offers potential oncologic benefit to the CRC patients incorporating the benefits of mCME with CLV, robotic mini-invasivity, fluorescence lymph node mapping and real-time assessment of the blood flow of the anastomosed intestinal walls.

DISCUSSION

We introduce a novel technique of double ICG administration during robotic right hemicolectomy for CRC cancer that enables improved lymphadenectomy and warrants the extent of intestinal resection. It contains the intrinsic solution to the potential risks related to more intense dissection for extended lymphadenectomy. This is an immediate assessment of blood supply to the anastomosed intestinal walls.

ICG fluorescence has immanent advantages as a result of its very low toxicity, high sensitivity, fast feedback and absence of radiation.[9] It is helpful to determine the extent of a bowel resection and can avoid leaving positive lymph nodes behind. It was revealed that ICG accurately evaluate the blood supply to anastomotic sites in real-time and can detect organ ischemia before reconstruction is performed. This is particularly useful in MI surgery, as detection of impaired blood supply is difficult and even more for intracorporeal anastomosis.[10] Lower anastomotic leak and reoperation rate were revealed with the use of ICG in several studies.[11]

Lymph nodes’ metastases are the most important prognostic factor in CRC, which has a poor prognosis and high recurrence.[12] The use of ICG in identification of lymph flow and lymphadenectomy basin in CRC patients has been previously reported.[13] Lymph drainage of the right-side colon is complicated, and understanding this lymphatic drainage system is difficult, making ICG fluorescence particularly useful in right-sided CRC patients.[14] Although there are reports of an 18.9% rate of upstaging of micrometastases, no lymphatic understaging has been reported with the use of ICG fluorescence.[15] In a study from Japan, planned lymphadenectomy was changed in 23.5% of cases with the use of ICG.[10]

The presented technique has some limitations. ICG fluorescence is not yet a quantitative but only a qualitative method; thus, the visual assessment is on surgeon's discretion. Further, we do not evaluate washout, i.e., the venous outflow is an important factor as a cause of the late leaks. However, fluorescence is the only objective technique available to reveal the viability of the tissues. Another limitation is a rapid diffusion of ICG to surrounding tissues that, in some cases, can obscure view and make judgement and interpretation somewhat uncertain.

CONCLUSIONS

We believe that double application of ICG in robotic right hemicolectomy for lymph node mapping and blood flow evaluation provides the surgeon an important tool to optimise the staging and treatment of right-sided CRC patients. The proposed procedure could improve radicality throughout extended lymphadenectomy but also ensure accurate staging, and therefore, subsequent oncological management. It seems a strong candidate for gold standard in robotic resections of the right colon for CRC; however, further RCS with long-term follow-up is needed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.