Totally laparoscopic colectomy is accepted and performed as a method, showing improvement in the surgical treatment for colon cancer. Many obvious advantages of totally laparoscopic colectomy have been revealed as compared with conventional laparoscopic-assisted colectomy. Carmelo Magistro et al. thought direct manipulation of the bowel trait harboring the lesion is minimized and the entirely intracorporeal procedure decreased the traction of the mesentery and the risk of anastomotic twist . Francesco Roscio et al. thought that totally laparoscopic surgery would be an ideal treatment for patients with higher BMI, because it prevented extensive incisions for the extraction of large specimens through very thick abdominal walls and reduced the risk of microlacerations during the exteriorization of heavy and short mesenteries . Ilknur Erguner et al. thought that totally laparoscopic surgery avoided ischemia–reperfusion of the colon during extracorporeal anastomosis for a minimum of 5–10 min and provided a free specimen extraction site such as suprapubic incision or the natural orifices, which would offer less adhesions, less incisional hernia, and better cosmesis . Our previous studies also found that totally laparoscopic surgery for colon cancer had the advantages of less postoperative pain and earlier time to first flatus, which promises a safe and feasible procedure with satisfactory short-term outcomes [13-14].
However, different from conventional extracorporeal anastomosis, the evaluation of bowel perfusion under laparoscopy may be difficult for beginners due to the lack of stereoscopic vision, while the judgment of perfusion may be a key factor for the healing of an anastomosis in colonic surgeries. Generally, surgeons assessed the vascular anastomotic perfusion by active bleeding from the resection margin, palpable pulsation in the mesentery, or lack of discoloration, which was subjective, highly unreliable, and time-consuming . Doppler ultrasound, laser Doppler flowmetry, angiography, and oxygen spectroscopy are thought to be reliable methods to evaluate bowel perfusion, which were not widely used in the surgical field due to the price of equipment, technical difficulties, and lack of reproducibility [16-17].
ICG is a sterile, anionic, water-soluble solution but with relatively hydrophobic and tricarbocyanine molecules with the weight of 775 Da, which absorbs light between 790 and 805 nm and re-emits it with an excitation wavelength of 835 nm presented as a fluorophore in response to NIR irradiation . After an intravenous injection, ICG rapidly and extensively binds to the plasma protein, with minimal leakage into the interstitium. With the half-life of 3–5 min, ICG is cleared by the liver in 15–20 min into bile with no known metabolites. Intravenous use is reported to be very safe generally, and cases of vasovagal or allergic reactions such as anaphylactic shock, hypotension, tachycardia, dyspnea, or urticaria are extremely rare. These properties make ICG an ideal agent for the acquisition of high-quality images of both the circulatory and lymphatic systems [7-9].
The recently developed IGFI facilitates easy performance of intraoperative fluorescence angiography and has been used to evaluate the real-time perfusion of the resection margin during a laparoscopic surgery [18-20]. It was reported in some meta-analysis that ICG fluorescence imaging was an effective tool to assess anastomotic perfusion and reduced anastomotic leakage rates in patients undergoing colorectal resection [21-22]. Some multicenter randomized controlled trials also found that intraoperative ICG fluorescent angiography could effectively assess vascularization of the anastomosis and lead to a reduction in anastomotic leak in in colorectal surgery [23-24].
Based on these studies, we applied the technique of IGFI in totally laparoscopic surgery for colon cancer and evaluate the feasibility, safety, and short-term outcomes. Some studies assessed the perfusion of colonic tissue based on the integrity of the mucosal aspect of the completed anastomosis using fluorescence angiography via proctoscopy . The conversion of different devices added the total operation time. During a totally laparoscopic surgery for colon cancer, we used IGFI to evaluate the bowel perfusion only under laparoscopy, and the mean operation time is 125.8±34.9 min, which is significantly shorter than the control group, and we attributed this difference to the fast and accurate judgment of bowel perfusion and the simplicity of this procedure. Moreover, the mean time to perfusion fluorescence in this study was 48.4±14.0 s after the injection of ICG. Therefore, we thought the overall operation time was not prolonged due to the application of this new technique, which conversely shortened the total time due to the quick operation during the selection of resection margin. In fact, during totally laparoscopic surgery for colon cancer, we found that IGFI was easy to implement with a short learning curve due to the similarity of this device with a standard laparoscope.
Our results indicated that the assessment of perfusion at the proximal and distal resection margins was associated with revision of the surgical plan in nearly 4.8% of patients and the percentage was not low during a totally laparoscopic surgery. We thought that the microperfusion deficiency of the transected bowel and planned site of anastomosis could not be found by conventional methods of assessment and may be not entirely reliable. Further, patients who underwent further ‘‘re-resection’’ up to a ‘‘fluorescent’’ portion due to insufficient bowel perfusion in this study were those with left colectomies. With regard to the reason, previous studies found the blood pressure of marginal artery was reduced by ≥30% after the blockage of the left colic artery and unstable blood flow to the left colon occurred after IMA ligation in approximately 10% of patients, which could increase the rate of insufficient perfusion [26-27]. Therefore, we confirmed that insufficient perfusion of the bowel may more frequently occur in patients with left colon cancer, and we should focus more on the bowel perfusion in totally laparoscopic left hemicolectomy, especially for the proximal margin.
IGFI was used to guarantee a reliable anastomosis, in order to prevent complications related to the anastomosis. Previous studies have clearly demonstrated that IGFI can reduce anastomotic complications, and the incidence of complications in this study was 11.9 %, which was similar to that of other studies [28-29]. Fortunately, no patient suffered anastomotic leak and only one patient suffered anastomosis-related bleeding that was successfully treated conservatively. Benign anastomosis-related stricture after the colorectal anastomosis occurs in some patients, and its occurrence is not rare. Preoperative radiation, anastomosis-related ischemia, leakage, and the anastomosis technique are all thought to be related to the development of anastomotic stricture . In this study, no patient suffered from anastomotic stricture, which can be attributed to a reliable intraoperative real-time blood flow evaluation by IGFI and advanced overlapped delta-shaped anastomosis, in which the staple line in the anastomotic stoma appeared as a curving obtuse triangle after the digestive tract reconstruction.