Anastomotic Leakage Risk Score

Risk Factor Assessment

Each factor present = 1 point. Total score 0–7.

Male sex BMI ≥25 kg/m² Anastomosis <10 cm from anal verge (low colorectal / coloanal) Cardiac disease (IHD, CCF, arrhythmia requiring treatment) Diabetes mellitus Intraoperative complications (bleeding >200 mL, enterotomy, technical difficulty) Blood transfusion intraoperatively (>2 units)

Score: 0 / 7

Leakage Risk Score

Low Risk — ∼3% AL rate

Defunctioning stoma not routinely required.

Risk Factor Scoring

Risk Factor	Points
Male sex	1
BMI ≥25 kg/m²	1
Anastomosis <10 cm from anal verge	1
Cardiac disease	1
Diabetes mellitus	1
Intraoperative complications	1
Intraoperative blood transfusion >2 units	1
Maximum score	7

Interpretation & Stoma Recommendation

Score	AL Risk	Defunctioning Stoma
0–3	~3%	Not routinely indicated
4–5	~8%	Consider (especially if anastomosis <6 cm from verge)
6–7	~20%	Strongly recommended

Anastomotic Leakage Definition

AL is defined as clinical or radiological evidence of leakage from the anastomosis. Graded A/B/C by ISREC (International Study Group of Rectal Cancer):

Grade A: No clinical change; radiological finding only — no active treatment required
Grade B: Active intervention required (antibiotics, IR drainage) but no re-operation
Grade C: Re-operation required

Additional Risk Factors (Not in Score)

Neoadjuvant radiotherapy: significantly increases AL risk — long-course chemoradiation carries highest risk
Prolonged operative time >3h: independent risk factor in multiple series
Laparoscopic vs open: similar AL rates overall; robotic approach may reduce AL in low rectal anastomosis
Incomplete doughnut on circular stapler: mandates on-table check and consideration for defunctioning
Air leak test / pelvic water test: should be routine for all left-sided anastomoses

Clinical Application

A defunctioning loop ileostomy does not prevent anastomotic leakage but reduces the clinical consequences and avoids emergency reoperation in the event of a leak
Water-soluble contrast enema at 6–8 weeks before stoma reversal is standard of care
Anastomotic leak is the most morbid post-operative complication — mortality 10–15% when presenting with sepsis
Intraoperative factors (tissue ischaemia, tension, inadequate blood supply, low anastomosis) remain paramount in determining AL risk

References

Dekker JWT, et al. Multivariate analysis of ex vivo and in vivo factors influencing the outcome of anastomotic leakage after colorectal surgery. Int J Colorectal Dis. 2011;26(12):1559–1566.
McDermott FD, et al. Systematic review of preoperative, intraoperative and postoperative risk factors for colorectal anastomotic leaks. Br J Surg. 2015;102(5):462–479.