Anastomotic Leak

An anastomotic leak is a defect in a surgically created gastrointestinal anastomosis that allows communication between the bowel lumen and the extraluminal compartment.

Severity ranges from an asymptomatic radiological defect to free faecal contamination with septic shock.

The International Study Group of Rectal Cancer classification is clinically useful:

• Grade A: no change in treatment
• Grade B: requires active treatment without relaparotomy
• Grade C: requires relaparotomy

Management is determined primarily by physiological stability, whether contamination is contained, abscess size, tissue viability and ability to achieve source control.

Presentation may be dramatic or subtle.

Suspect a leak with:

• Persistent postoperative tachycardia
• New or recurrent fever
• Increasing abdominal or pelvic pain
• Prolonged ileus
• Purulent or enteric drain output
• Faecal material from the wound
• Rising inflammatory markers after an initial postoperative improvement
• New organ dysfunction or septic shock

Low pelvic leaks may produce pelvic sepsis with relatively little generalised peritonism, particularly when a diverting stoma is already present.

CT abdomen and pelvis with IV contrast, with water soluble enteric or rectal contrast when appropriate: preferred investigation in a stable patient; look for extraluminal contrast or a collection communicating with the anastomosis.

Do not delay source control for imaging in an unstable patient with diffuse peritonitis.

Begin resuscitation and antibiotics immediately when clinically significant leakage is suspected.

For stable community acquired postoperative intra abdominal infection without major resistant organism risk:

Ceftriaxone 2 g IV every 24 hours plus metronidazole 500 mg IV every 12 hours.

For severe sepsis, healthcare associated infection or significant resistant organism risk:

Piperacillin tazobactam 4.5 g IV every 8 hours by extended infusion, adjusted for renal function.

A clinically stable patient with a small contained leak and no uncontrolled sepsis may be managed with bowel rest, antibiotics and close observation.

A well formed collection larger than approximately 3 cm is usually better managed with image guided drainage when technically accessible.

Operate for:

• Generalised peritonitis
• Septic shock
• Free uncontrolled leak
• Ischaemic anastomosis
• Failure of nonoperative source control
• Clinical deterioration despite drainage and antibiotics

The operative objective is source control, not obligatory preservation or destruction of the anastomosis.

For an inaccessible low pelvic anastomosis surrounded by severe inflammation, washout, adequate drainage and proximal diversion may be safer than attempting difficult takedown.

A grossly disrupted or ischaemic anastomosis usually requires resection. Options include end stoma formation or reanastomosis with proximal diversion in a stable patient with healthy tissue.

After adequate source control, antimicrobial treatment should generally not exceed 4 days unless infection remains uncontrolled.

Persistent sepsis after apparently adequate treatment should trigger repeat source control assessment, not repeated extension of antibiotics.