Editing Anastomosis (section)

== '''Anastomotic leak''' ==

=== '''Incidence''' ===

** Ileocolic anastomosis: 1-3%
** Colo-anal anastomosis: 20%
** Majority become apparent      between day 2 and 7 (median 5.5), but up to 12% can appear 1 month after      surgery

=== '''Risk     factors:''' ===

** '''Patient      factors:'''
*** Patient nutritional status
**** Often use albumin as a        proxy for nutritional status
**** However, the difference is        probably small unless profound malnutrition is present
*** Microbiome
**** E.g. some species may        favour production of certain proteins
**** Unanswered questions        around the role of pre-op Abx and the role of topical Abx at        anastomotic site
*** Medications
*** Radiotherapy to area
*** Male gender
*** Obesity
*** ASA score III or IV
*** Emergency operation
*** Use of oral anticoagulants
** '''Operative      factors:'''
*** Tension
**** Unsubstantiated at        individual patient level
*** Hypoperfusion
**** Especially any vasopressor        requirement
**** ?diminished oxygen tension        - hypoxia may impair collagen synthesis
**** Coronary artery disease
**** Radiotherapy to pelvis        prior
*** Multiple stapler firings
*** Needs to be water- and       air-tight, and technically sound, regardless of specific technique used
*** Mesentery
**** Kono-S anastomosis may        help by excluding diseased mesentery
*** Geometrical anastomosis       construction
*** Low extraperitoneal       anastomosis
*** Surgeon experience
*** Diverting stoma
**** Does not decrease        incidence of leak, but does reduce severity and lower risk of        re-operation

=== '''Presentation/evaluation:''' ===

** Clinically - fever sepsis,      abdominal pain, prolonged ileus, leucocytosis, CRP, raised pro-calcitonin
** Using CRP
*** Probably worth doing daily       CRP up to day 5
*** If there are two >50       increases in a row, pretty specific for leak
*** If do all five days and       never increases by >50 between any two, sensitivity 0.85 for leak
*** Increase >50 between two       days on day 3 or later is >0.90 specific for leak
*** Mean values from a 2023       meta-analysis comparing leak/no leak. Note multiply mg/dl by 10 to reach       mg/L.
**** CRP >159 on D3 is 77%        sp/74% se/LR+ 3.21/LR- 0.29
**** CRP >114 on D4 is 76%        sp/78% se/LR+ 3.29/LR- 0.24
**** CRP >109 on D5 is 80%        sp/76% se/LR+ 3.81/LR- 0.26

* CT - intra-abdominal or     peri-anastomotic fluid collections and gas, or based on Gastrografin enema

=== '''Treatment''' ===

** Subclinical (minimal      discharge from drains, no systemic signs) - conservative management with      close observation, antibiotics, bowel rest, TPN
*** If there are no drains,       likely get enteric contents leaking, leave it as a controlled fistula,       apply SNAPS principles
*** Large proportion will close       spontaneously
*** If it hasn't closed by six       weeks, elective re-operation to make a new anastomosis
** Abscess
*** Small peri-anastomotic       abscess - percutaneous drainage with medical management
*** Complex intra-abdominal       abscesses not suitable for or responding to percutaneous drainage -       surgery
** Peritonitis or sepsis (even      if minimal) - re-operation as soon as possible
*** Only resect and       re-anastomose in VERY select patients - stable patient, minimally       compromised, minimal peritonitis, good-quality bowel
*** Leak involves less than a       third of anastomosis and minimal contamination: diverting stoma or       directly exteriorise the leak
*** Leak is larger or the       anastomosis is disrupted: dismantle the anastomosis and create a       terminal stoma (can consider just redoing the anastomosis for an       ileocolic anastomosis, but safer to bring out as end ileostomy)