Authors (including presenting author) :
Foo CC(1), Ng KK(2), Tsang J(2), Wei R(2), Chow F(2), Chan TY(2), Lo O(2), Law WL(1)
Affiliation :
(1) Department of Surgery, University of Hong Kong (2) Department of Surgery, Queen Mary Hospital
Introduction :
Anastomotic leakage (AL) after colorectal resection results in significant morbidity and increases the chance of mortality. The risk of local recurrences and cancer specify survival are also adversely affected after cancer surgery (1, 2). The surge in health cost is a burden to the health care provider (3). Despite advances in surgical techniques, AL remains a significant problem with the highest incidence in left-sided colorectal resection(3). The rate of AL after low rectal resections varies from 2 to 39% in the literature(4). The cause of AL is multifactorial. Male gender, low rectal anastomosis and history of pelvic irradiation are some of the known risk factors of AL (5). Hypoperfusion to the anastomosis is one of the potential modifiable risk factors of AL(6). There is recent interest in using indocyanine green fluorescence imaging (ICG FI) to perform real-time intraoperative assessment of colonic perfusion. Multiple observational studies have reported favorable outcomes with this technique(7-10). Nevertheless, one of the multicenter randomized study was hampered by slow recruitment and was terminated prematurely(11).
Objectives :
The aim of this study was to ascertain whether the use of ICG FI was associated with a lower anastomotic leakage rate.
Methodology :
This was a retrospective study carried out in a single academic institution with approval from the institutional review board. Consecutive patients undergoing elective left-sided colorectal resections during the period of year 2013 to 2018 were included. Only colorectal resections that involved the ligation of the inferior mesenteric artery, i.e. anterior resections and low anterior resections were included. Cases which did not involve the ligation of inferior mesenteric artery, i.e. sigmoidectomies or left hemicolectomies were excluded. Cases in which primary anastomosis were not performed were excluded. Multi-visceral resections, pelvic exenterations and total proctocolectomy with ileo-pouch anal anastomosis were also excluded.
Those operated from 2013 to 2015 were labeled as group ICG-. ICG FI was routinely used in all elective left-sided resections since 2016 and those who were operated between 2016 to 2018 were labeled as ICG+. Their clinical outcomes were compared and the primary outcome was the rate of AL (within 60 days) and anastomotic stricture.
The International Study Group of Rectal Cancer definition of AL was adopted(14). Grade A (asymptomatic leakage) was defined as leakage detected on imaging, without any clinical symptoms or abnormal laboratory findings. Grade B was defined as anastomotic leakage that required active therapeutic intervention without the need for re-operation. Grade C was defined as AL that required re-operation. The secondary outcome was anastomotic stricture. Strictures were defined as narrowing of anastomosis that required digital, bougie or endoscopic dilatation.
Patients in the two groups were matched according to history of pelvic irradiation and anastomotic height, using propensity scores. The matching was one to one, using the nearest neighbor method and a tolerance of 0.05. The incidence of AL and anastomotic stricture were compared between the two groups. Categorical variables were compared with the χ² test or Fisher’s exact test when appropriate. Continuous variables were compared with the independent sample T test. A p value of < 0.05 was considered statistically significant. Univariate analysis was performed for the association between various clinicopathological parameters and AL. Multivariate analysis was performed by logistic regression using the stepwise forward likelihood ratio method, with AL being the dependent variable and clinicopathological parameters with p< 0.1 in the univariate analysis as the independent variables. Statistical analysis was performed using IBM SPSS version 25 (IBM, USA).
Result & Outcome :
There was a total of 258 and 317 patients who had surgery with and without ICG FI respectively. After propensity score matching, 253 patients from each group were compared. The overall leakage rate was 3.6% and 7.9% for ICG+ and ICG- respectively, p=0.035. Subgroup analysis showed that the anastomotic leakage rate was 4.7% and 11.6% after total meosrectal excision (TME) for ICG+ and ICG- respectively, p=0.043. Univariate analysis showed that male gender, longer operation duration, more distal anastomosis, TME, hand-sewn anastomosis, coloanal anastomosis and the absence of ICG FI were associated with AL. In addition to the above variables, history of pelvic irradiation was also included in the multivariate analysis model. The model showed that the use of ICG FI (p=0.032, OR 0.408, 95% CI 0.179-0.926), gender (p=0.021, OR 3.573, 95% CI 1.210-10549) and anastomotic height (p=0.006, OR 0.860, 95% CI 0.773-0.958) were independent predictors of AL. Conclusion The use of ICG FI was associated with a significantly lower AL rate. The difference was mainly seen in patients who had TME. The difference in the rate of AL in non-TME cases was not significant. The rate of anastomotic stricture was similar in those with and without ICG FI. This study supported the routine use of ICG FI in TME cases.
