Anastomotic Leak Risk Calculator – Can it be Used to Predict Anastomotic Leaks in Colonic Surgeries?

Keywords

Anastomotic Leak - colonic surgery - post operative complications

Introduction

Anastomotic leak after a large bowel surgery is the most dreaded complication with incidence ranging from 1.8%[1] to 15.9%.[2] AL is also associated with increased morbidity, mortality, length of hospital stays, general quality of life, and oncological outcomes when surgery is done in malignant diagnoses. A proximal diversion stoma is made when the risk of AL is anticipated to be high in a certain set of patients. This estimated risk however is subjective, it can change from surgeon to surgeon and is not highly reliable.

The risk of AL needs to be tailored for each patient separately – based on various factors. These factors can be broadly categorized into – baseline characteristics which include gender, age, nutritional status, comorbidities, diagnosis ; Intraoperative factors which include duration of surgery, type of anastomosis, location of anastomosis, surgical technique, intraoperative complications; post-operative factors which include the hospital setting where the post operative recovery occurs, post operative blood transfusions, if a leak occurs- how early was it diagnosed.

In the last two decades, there have been many studies which have been done, both prospectively and retrospectively to identify the factors that have significant effect on the probability of anastomotic leak in large bowel surgeries. Choi HK et al,[1] in 2004 published a study, where they prospectively analyzed 1417 patients who underwent resection and anastomosis above the peritoneal reflection for colorectal carcinoma. It was found that the duration of hospital stays (28 days vs 10 days, p < 0/01%), and mortality rate (32% vs 4%) was significantly higher in patients who had an anastomotic leak post operatively. They had also concluded that American Society of Anesthesiologists grade, whether the procedure was emergent or elective, if the patient was a smoker or an alcohol user pre-operatively were also independent risk factors for AL.

In 2006, Konishi et al,[3] had published a prospective study where the studied the incidence of ALs in a single center where colorectal resections have been performed from 2000-2004 by a single surgeon. 11 patients out of 391 (2.8%) had AL. Preoperative steroid use, longer intraoperative time were independently predictive of the incidence of anastomotic leak.

When a patient gets diagnosed with a colonic pathology (benign or malignant), to make a surgical treatment plan for the patient, multiple factors need to be taken into consideration and the plan should be tailored to each patient separately, rather than a community or an age group or a set of diagnoses.

However, most data and studies combine both colon and rectal surgeries, because of this, factors specific to colon surgery are often obscured by risk factors which are typical to rectal surgeries – like male sex, level of mesenteric artery ligation, distance of the tumor form the anal verge, and the use of neoadjuvant radiotherapy (which is more commonly done in rectal carcinomas).

Kraup PM et al,[4] in 2012 published a study in Denmark, where 9333 patients who underwent curative colonic resection with a primary anastomosis without a stoma were studied. AL occurred in 593 (6.4%) patients. Laparoscopic surgery, left hemicolectomy, sigmoid colectomy, intraoperative blood loss and blood transfusions, and male gender were found to be associated with an increased risk of AL.

Majority of the studies identify risk factors but don't provide an accurate instrument to estimate the risk of AL in daily clinical practise. If a tool like that can be made, patients at a higher risk of AL can be identified preoperatively, and their surgical plan can be modified, a diversion stoma could be made, or an anastomosis could be avoided, accordingly.

In 2015, the ANACO study group published a multicentric, prospective study done in Spain from September 2011 to September 2012.[5]

They aimed to determine the pre-operative and intra-operative risk factors for anastomotic leak after colon resection and to create a practical instrument to predict the leak. They included 3193 patients, evaluated 42 pre-operative and intraoperative factors, and studied the occurrence of AL in 60 days post-surgery. Using univariate and multivariate analysis, they identified obesity, intra-op complications, pre-op serum protein levels, male sex, hospital beds, and ongoing anticoagulants as statistically significant factors for AL. Based on this, they developed a nomogram using a logistic regression model which can be used to calculate the AL risk percentage for each patient.

This nomogram has been externally validated by multiple studies. Sammour et al, in a retrospective analysis published in 2017,[6] compared this Anastomotic Leak Risk Calculator to American College of Surgeons National Surgical Quality Improvement Program^® (ACS NSQIP) calculator[7] and the colon leakage score (CLS) calculator for left colectomy. In another prospective analysis, this calculator has been proven to be superior to the surgeon's estimate of AL after colon cancer resection.[8]

In our study, the Anastomotic leak risk calculator[5] is being evaluated in colonic surgeries being performed in our institution.

Methodology

Aim:

To evaluate the Anastomotic Leak Risk Calculator in predicting the outcome of Colonic Anastomosis in right-sided and left-sided colonic surgeries

Objectives:

• To calculate and compare the Anastomotic Leak Risk Score pre-operatively and post-operatively considering intraoperative complications as an independent variable

• To identify pre-operative and intra-operative variables that are significant in predicting anastomotic leak

Study Design

This is a prospective, observational study, done in a single center, from November 2022 to May 2024. The departments of General Surgery, Surgical Oncology, Gastrointestinal Surgery, at Kasturba Medical College, Manipal were included. Our study was a time-bound study, and it included all the patients who fit the inclusion criteria admitted during the study duration, hence, the sample size was 89.

Inclusion and Exclusion Criteria

Inclusion Criteria

Patients who underwent colectomy on an emergency/elective basis with or without a protective stoma between November 2022 to May 2024

Exclusion Criteria

• Patients less than 18 years

• Patients with incomplete information

Materials and Methods-

Prior approval was sought from the institutional ethics committee. After obtaining informed consent from the patient, information was collected in a proforma. The data was then used to derive the Anastomotic Leak Risk Score using the Anastomotic Leak Risk Calculator (www.anastomoticleak.com).[5] This calculator was chosen for the study as it is widely used with multiple validation studies and has also been included in the European Society of Coloproctology (ESCP) driven 2019 Safe-anastomosis Programme in Colorectal Surgery (EAGLE).[9] The variables included in this calculator are gender, BMI, on anticoagulants, intra operative complications, serum protein level, hospital size (number of beds).

Outcome

The outcome was to look for anastomotic leak 30 days post operatively

Definitions

• • Anastomotic leak was defined as -

“Leak of luminal contents from a surgical join between 2 hollow viscera” diagnosed

• (1) radiologically, by a radiographic enema with hydro-soluble contrast or by computerized tomography (CT) with presence of intra- abdominal collection adjacent to the anastomosis

• (2) clinically, with evidence of extravasation of bowel content or gas through a wound or drain

• (3) by endoscopy

• (4) intraoperatively.

  • • Intra-operative complications were defined as the presence of one or more of the following

    • - Iatrogenic injury to the bowel, vessels or other organs

    • - Bleeding (more than 500ml)

    • - Stapling device malfunction

    • - Re-doing anastomosis due to technical issues

    • - Prolonged duration of surgery (more than 5 hours)

Data Analysis

Categorical data was summarized by frequency and percentages. Quantitative data was summarized by mean and standard deviation. Comparison of categorical data was performed by Chi-square test and Fisher's exact test. Quantitative data was compared by t-test. SPSS 23 software was used to analyze the data. The level of significance was 5%. A multivariate regression analysis has not been performed as our primary objective was to evaluate the Anastomotic leak risk calculator in predicting the risk of ALs. Had the objective been to develop a nomogram to predict ALs in our study setting, a multivariate regression analysis may have been used.

Results

The descriptive statistics of the study population are tabulated below ([Table 1]):

Table 1 Descriptive statistics of the study population

	Variables		N (%)
Baseline Characteristics	Gender	Male	55 (61.8%)
		Female	34 (38.2%)
	Anticoagulant usage	Not on anticoagulants	78 (87.6%)
		Taking but stopped preoperatively	7 (7.9%)
		Taking at the time of surgery	4 (4.5%)
	Age	30 years and below	9 (10.1%)
		31 - 50 years	25 (28.1%)
		51 - 70 years	39 (43.8%)
		Above 70 years	16 (18%)
	Diagnosis	Malignancy	60 (67.4%)
		Benign	26 (29.2%)
		Mesenteric ischemia	3 (3.4%)
Variables related to the surgery	Name of the surgery	Emergency	17 (19.1%)
		Elective	72 (80.9%)
	Type of the surgery	Open	63 (71%)
		Laparoscopic	22 (25%)
		Laparoscopic converted to open	4 (4%)
	Site of the anastomosis	Colo-colic (left side)	28 (31.5%)
		Ileo-colic (right side)	61 (68.5%)
	Type of the anastomosis	End to end	17 (19.1%)
		Side to side	70 (78.7%)
		End to side	2 (2.2%)
	Handsewn vs stapled	Handsewn	40 (45%)
		Stapled	49 (55%)
	Covering stoma	No	82 (92.1%)
		Yes	7 (7.9%)
	Intraoperative complications	Yes	33 (37%)
Post operative outcomes	Time from surgery to discharge	3 - 5 days	37 (41.5%)
		6 - 10 days	30 (33.7%)
		Above 10 days	22 (24.7%)

[Table 2] summarizes the values of BMI.

Table 2 BMI range in the study population

BMI	Number (total = 89)	%
>30 kg/m2	10	11.2%
<30kg/m2	79	88.8%

([Graph 1])

Graph 1 summarizes the serum protein distribution in the study population.

[Table 3] summarizes the quantitative data analyzed in the study.

Table 3 Quantitative data analysed in the study

	N	Minimum	Maximum	Mean	Std Deviation
BMI	89	13.15	38.46	23.93	5.18
Serum protein	89	4.5	8.4	6.71	0.934
Time from surgery to discharge	89	3	46	9.66	6.403
Age	89	19	88	53.87	16.221

Anastomotic Leak-

[Tables 4], [5], [6] summarize the incidence of anastomotic leak in our study population, mode of diagnosis of AL and treatment for the AL.

Table 4 Incidence of AL in the study population

Anastomotic Leak Diagnosed	Number (n = 89)	Percentage
No	83	93.3%
Yes – Disruption of Anastomosis	4	4.5%	6.7%
Yes – Enterocutaneous fistula	2	2.2%

Table 5 Mode of diagnosis of AL

Mode of diagnosis	Number	Percentage
Clinical	2	33.4%
Radiological	4	66.6%
Intra-operatively	0	0%
Endoscopic	0	0%

Table 6 Treatment given for AL

Treatment	Number	Percentage
Re-operation	4	66.6%
Antibiotics	2	33.4%

Variables Compared with the Incidence of Anastomotic Risk

[Table 7] summarizes the baseline characteristics of the study population compared with incidence of AL.

Table 7 Baseline characteristics of the study population compared with the incidence of AL

	Variables compared with the incidence of Anastomotic leak		N (%)	Anastomotic leak	Number (% in category)	Percentage in total anastomotic leak	p-value
Baseline characteristics	Gender	Male	55 (61.8%)	Present Absent	2 (3.6%) 53 (96.4%)	2 out of 6 ALs (33.3%) occurred in Males	0.137 (Chi-square) (NS)
		Female	34 (38.2%)	Present Absent	4 (11.8%) 30 (88.2%)	4 out of 6 ALs (66.6%) occurred in females
	Anticoagulant usage	Not on anticoagulants	78 (87.5%)	Present Absent	5 (6.4%) 73 (93.6%)	5 out of 6 ALs (83.3%) occurred in patients not on anticoagulants	0.267 (Fisher's exact) (NS)
		Taking but stopped preoperatively	7 (7.9%)	Present Absent	0 (0%) 7 (100%)
		Taking at the time of surgery	4 (4.5%)	Present Absent	1 (25%) 3 (75%)	1 out 6 ALs (16.6%) occurred in patients taking anticoagulants
	Age	30 years and below	9 (10.1%)	Present Absent	1 (11.1%) 8 (88.9%)	1 out of 6 ALs (16.6%) occurred in patients of age 30 yrs and below	0.476 (Fisher's exact) (NS)
		31-50 years	25 (28.1%)	Present Absent	1 (4%) 24 (96%)	1 out of 6 ALs (16.6%) occurred in patients of age 31-50 yrs
		51-70 years	39 (43.8%)	Present Absent	4 (10.3%) 35 (89.7%)	4 out of 6 ALs (66.6%) occurred in patients between 51-70 yrs
		Above 70 years	16 (18%)	Present Absent	0 (0%) 16 (100%)	0%
	Diagnosis	Malignancy	60 (67.4%)	Present Absent	2 (3.3%) 58 (96.7%)	2 out of 6 ALs (33.3%) occurred in malignant conditions	0.066 (Fisher's exact) (NS)
		Benign	26 (29.2%)	Present Absent	3 (11.5%) 23 (88.5%)	3 out of 6 ALs (50%) occurred in benign conditions
		Mesenteric ischemia	3 (3.4%)	Present Absent	1 (33.3%) 2 (66.7%)	1 out of 6 ALs (16.6%) occurred in mesenteric ischemia

[Table 8] summarizes the operative variables of the study population compared with incidence of AL.

Table 8 Variable related to the surgery compared with the incidence of AL

	Variables compared with the incidence of anastomotic leak		N (%)	Anastomotic leak	Number (% in category)	% of total leaks	p-value
Variables related to the surgery	Name of the surgery	Emergency	17 (19.1%)	Present Absent	0 (0%) 17 (100%)	0 out of 6 ALs occurred in emergency surgeries	0.218 (Chi-square test) (NS)
		Elective	72 (80.9%)	Present Absent	6 (8.3%) 66 (91.7%)	6 out 0f 6 ALs (100%) occurred in elective surgeries
	Type of the surgery	Open	63 (71%)	Present Absent	6 (9.5%) 57 (90.5%)	6 out of 6 ALs occurred in open procedures (100%)	0.265 (Fisher's exact test) (NS)
		Laparoscopic	22 (25%)	Present Absent	0 (0%) 22 (100%)
		Laparoscopic converted to open	4 (4%)	Present Absent	0 (0%) 4 (100%)
	Site of the anastomosis	Colo-colic (left side)	28 (31.5%)	Present Absent	4 (14.3%) 24 (85.7%)	4 out of 6 ALs (66.6%) occurred in left sided anastomosis	0.004 (Fisher's exact test) (HS)
		Ileo-colic (right side)	61 (68.5%)	Present Absent	2 (3.2%) 59 (96.8%)	2 out of 6 ALs (33.3%) occurred in left sided anastomosis
	Type of the anastomosis	End to end	17 (19.1%)	Present Absent	2 (11.8%) 15 (88.2%)	2 out of 6 (33.3%) ALs occurred in E-E	0.624 (Fisher's exact test) (NS)
		Side to side	70 (78.7%)	Present Absent	4 (5.7%) 66 (94.3%)	4 out of 6 (66.6%) ALs occurred in S-S
		End to side	2 (2.2%)	Present Absent	0 (0%) 2 (100%)
	Handsewn vs stapled	Handsewn	40 (45%)	Present Absent	4 (10%) 36 (90%)	4 out of 6 ALs (66.6%) occurred in handsewn	0.218 (Chi square test) (NS)
		Stapled	49 (55%)	Present Absent	2 (4.1%) 47 (95.9%)	2 out of 6 ALs (33.3%) occurred in stapled
	Covering stoma	No	82 (92.1%)	Present Absent	6 (7.3%) 76 (92.7%)	6 out of 6 ALs occurred in patients without stoma	0.459 (Fisher's exact test) (NS)
		Yes	7 (7.9%)	Present Absent	0 (0%) 7 (100%)
	Intraoperative complications	Yes	33 (37%)	Present Absent	2 (6%) 31 (94%)	Only 2 of the 6 ALs (33.3%) had intraoperative complications	0.890 (Chi-square test) (NS)

[Table 9] summarizes the post operative outcomes of the study population compared with incidence of AL.

Table 9 Post operative outcomes compared with the incidence of AL

	Variables compared with the incidence of anastomotic leak		N (%)	Anastomotic leak	Number (% in category)	% of total leaks	p-value
Post operative outcomes	Time from surgery to discharge	3-5 days	37 (41.5%)	Present Absent	0 (0%) 37 (100%)	0%	0.002 (Chi-square test) (HS)
		6-10 days	30 (33.7%)	Present Absent	1 (3.3%) 29 (96.7%)	1 out of 6 ALs had hospital stay over 5 days
		Above 10 days	22 (24.7%)	Present Absent	5 (22.7%) 17 (77.3%)	5 out of 6 ALs had hospital stay over 10 days

Anastomotic Leak Risk Scores

Preoperatively Calculated Anastomotic Leak Risk Score

Preoperative anastomotic leak scores are categorized in [Table 10]

Table 10 Preoperative Anastomotic Leak Risk Score

Preoperative anastomotic leak risk score	Number (n =89)	Percentage
Less than 5%	34	38.2%
5% - 10%	38	42.7%
11% - 20%	16	18%
Above 20%	1	1.1%

Post-Operatively Calculated Anastomotic Leak Risk Score

Post operative anastomotic leak scores are categorized in [Table 11]

Table 11 Postoperative Anastomotic Leak Risk Score

Post-operative anastomotic leak risk score	Number (n =89)	Percentage
Less than 5%	25	28.1%
5% - 10%	33	37.1%
11% - 20%	23	25.8%
Above 20%	8	9%

([Graph 2])

Graph 2 shows the comparison between preoperative and post operative anastomotic leak risk scores.

The preoperative and post operative anastomotic leak risk scores were compared with the incidence of AL. the summary of this is depicted in [Table 12].

Table 12 Comparision of preoperative and postoperative anastomotic leak risk score with incidence of AL

Anastomotic leak diagnosed		N	Mean	Std. Deviation	t test p value
pre op score (%)	Yes	6	8.83	3.19	0.483	NS
	No	83	7.69	3.89
post op score (%)	Yes	6	11.17	5.04	0.661	NS
	No	83	9.98	6.46

Using t test, comparing the preoperative anastomotic leak risk score and Incidence of Anastomotic leak, p-value was determined to be 0.483, which is statistically not significant. Using the t-test, comparing the post operative anastomotic leak risk score and Incidence of Anastomotic leak, p-value was determined to be 0.661, which is statistically not significant

Intra Operative Complications and Anastomotic Leak Risk Score

Using occurrence of intra operative complications as an independent variable, pre-operative and post operative Anastomotic leak risk scores were calculated and data was analyzed. Results are shown in [Table 13], [14].

Table 13 Intraoperative complications and Anastomotic Leak Risk Score (Preoperatively)

Pre-operative Anastomotic Leak Risk Score	Intra operative complications - Yes		Intra operative complications - No
	Number	Percentage	Number	Percentage
Less than 5%	11	32.4%	23	67.6%
5% - 10%	14	36.8%	24	63.2%
11% - 20%	7	43.8%	9	56.3%
More than 20%	0	0%	1	100%

Table 14 Intraoperative complications and Anastomotic leak risk score (Postoperatively)

Post operative Anastomotic Leak Risk Score	Intra operative complications - Yes		Intra operative complications - No
	Number	Percentage	Number	Percentage
Less than 5%	2	8%	23	92%
5% - 10%	19	27.3%	24	72.7%
11% - 20%	14	60.9%	9	39.1%
More than 20%	7	87.5%	1	12.5%

Using Chi square test, the significance of the effect of presence of Intraoperative complications on the post operative anastomotic leak risk score has been assessed. p-value was determined to be <0.001 which is highly significant

Outcome at 30 Days in the Study Population

[Table 15] summarizes the outcome of the study population at 30 days post-surgery

Table 15 Outcome at 30 days

Outcome at 30 days	Number (n = 89)	Percentage
Discharged	78	87.6%
Leak present – treated by reoperation	2	2.2%
Leak present – treated by Antibiotics	2	2.2%
Death	7	7.9%

Out of the seven deaths, 2 deaths (28.6% of total deaths) were due to anastomotic leak.

Whereas 5 deaths (71.4% of total deaths) were due to other causes. (2 deaths – ARDS, 1 death – Intractable seizures, 1 death – Severe metabolic acidosis, 1 death – urosepsis, Congestive cardiac failure.

Using Fisher's exact test, comparing the outcome at 30 days and Incidence of Anastomotic leak, p-value was determined to be < 0.001, which is statistically highly significant

Discussion

The anastomotic leak risk calculator[5] has been validated by two studies as described earlier.[6] [8] In April 2022, Izel Omen at al published a multicenter prospective study using data collected from 2016–2019 at 14 hospitals in Australia and Netherlands.[10] The broadly included 643 patients who underwent colonic surgery with an anastomosis. They have concluded that the anastomotic leak risk calculator[5] could not be validated in their study population. Low pre-operative hemoglobin, intraoperative hypothermia, contamination of the operative field and use of epidural analgesia were identified as independent risk factors for AL. In retrospection, the reasons for failure of the Anastomotic leak risk calculator in predicting ALs in our study population could be due to two factors, one – the lower number of study population, two – the shorter follow up period. Since this study was a single center study, it included only patients from a single tertiary care center which would, had it been a multicentered study, it would have been possible to achieve a more sample size which is representative of the population. The previous studies which validated the anastomotic leak risk calculator have been tested only on right sided colonic surgeries[6] [8] whereas our study had considered both right and left sided colonic anastomoses which could have led to variation in the results. Since the follow up period in our study has been only 30 days, delayed presentations such as an enterocutaneous fistula could have been missed.

There have been many scores developed in the literature, using various factors that affect the healing of an anastomosis as variables. Notable ones have been compared to the current calculator.

Frasson et al.[5] did a study where 42 pre-/intraoperative variables, related to patient, tumor, surgical procedure, and hospital, were analyzed as potential independent risk factors for anastomotic leak with a 60 day follow up. A nomogram was created to easily predict the risk of anastomotic leak for a given patient. Anastomotic leak significantly increased mortality and length of hospitalization. In the multivariate analysis, obesity, preoperative serum total proteins, male sex, ongoing anticoagulant treatment, intraoperative complication, and number of hospital beds were identified to be independent risk factors for predicting AL.

Mc. Kenna[11] et al published a study with the data from ACS- NSQIP from 2012-2016 amongst patients undergoing elective left sided colon resection for a malignant or a benign disease. Independent risk factors for anastomotic leak included younger age, male sex, tobacco use, and omission of combined bowel preparation.

Rencyzogullari A, et al. developed a nomogram using the ACS-NSQIP data amongst elderly patients undergoing colectomy.[12] The duration of follow up post OT was 30 days. Based on unadjusted analysis, factors associated with an increased risk of an anastomotic leak were ASA score III and IV, chronic obstructive pulmonary disease, diabetes mellitus, smoking history, weight loss, previously infected wound, omitting mechanical bowel preparation and/or preoperative oral antibiotic use, and wounds classified as contaminated or dirty/infected. Patients who developed an anatomic leak had a longer length of hospital stay and operative time. A multivariate model and nomogram were created.

Rojas Machado et al, developed a PROCOLE score using a meta-analysis of observational studies of risk factors for predicting AL in patients undergoing colorectal cancer surgery.[13] The study involved a comprehensive review of observational studies to identify risk factors for AL. Based on the meta-analysis, significant risk factors for AL were selected. The PROCOLE index was created by incorporating these risk factors into a scoring system. Each risk factor was assigned a weight based on its association with AL. The PROCOLE index was validated using data from a separate cohort to assess its predictive accuracy and clinical utility. Risk Factors identified were – age, comorbidities, and nutritional status, type of anastomosis, surgical technique, and operative time, tumor location and stage. The index showed good performance metrics, including sensitivity, specificity, and an area under the receiver operating characteristic (ROC) curve.

Pasic et al, developed a score to predict AL after elective colorectal cancer surgery.[14] A total of 159 patients were divided into test (79 patients) and validation (40 patients) groups to identify the risk factors and construct the predictive score. The remaining 40 patients (intervention group) were prospectively evaluated with the application of protective measures guided by risk stratification according to the predictive score. The study identified several significant predictors of AL, including age, and nutritional status, type of anastomosis, operative time, and intraoperative complications, tumor location and stage. The predictive score combined these risk factors into a numerical value that estimates the risk of AL. The predictive score was used to guide decisions about implementing protective measures, such as creating an ostomy, for high-risk patients.

Our study was performed in a single center, prospectively, included 89 patients undergoing elective/emergent colonic surgeries (benign / malignant). Cases which had colorectal resection were excluded. The statistical analysis has revealed that the site of anastomosis (whether it is right sided or left side) significantly effects the anastomotic leak probability (p = 0.004). The incidence of AL significant influences the duration of hospital stays (p = 0.002) and 30 day outcomes (p < 0.001).

The comparisons of these studies have been made in [table 16] below:

Table 16 Comparision of similar studies

Summary	Current study	Frasson et al	McKenna et al	Rencyzogullari A et al	Rojas Machado et al	Pasic et al
Year	2024	2015	2019	2017	2016	2013
Country	India	Spain	USA	USA	Spain	Bosnia
Retrospective/ Prospective	Prospective	Prospective	Retrospective	Retrospective	Meta analysis, systematic review	Prospective
Single vs multicentric	Single center	Multicentric	Multicentric	Multicentric	Multicentric	Single center
Score name	−	Anastomotic leak risk score	−	−	PROCOLE	−
No. of patients included	89	3193	38475	10,392	Various factors were weighed in, not patients	159
Type of surgery included	Right and left colonic surgeries (excl rectal)	Right and left colonic surgeries (excl rectal)	Left sided colonic surgery	All colorectal surgery	All colorectal surgery	All colorectal surgery
AL %	6.7%	8.7%	3.3%	3.2%		8.7%

Conclusion

Anastomotic leak percentage in our study – 6.7% (6 out of 89 patients). The anastomotic leak risk calculator has not proven to be significant in predicting the risk of anastomotic leaks in our study population. The occurrence of intraoperative complications has a significant effect on the post operative anastomotic leak risk score. There is significant effect of the Site of anastomosis – left sided or right sided on the probability of occurrence of AL. The time from surgery to discharge of the patient is significantly affected by the occurrence of anastomotic leak. The incidence of AL significantly affects the 30-day outcome of the patient post-surgery. However, studies with a longer study duration and a longer follow up period are indicated to further analyze and evaluate the Anastomotic leak risk calculator.

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