22 – Adhesions Flashcards
What are adhesions?
- Type of ‘scar tissue’ form b/w organs and tissue after abdominal surgery
o Form as result of injured tissues during surgery
Dogs and cats: incidence of adhesions
- RARELY a problem after abdominal surgery
- *active fibrinolytic system
What are the 2 species that have issues with adhesions?
- Horses
- Humans
Horses: incidence of adhesions
- COMMONLY associated with surgical diseases of SI
- Most common cause of RECURRENT abdominal pain in horses after SI
- Most common reason for DEATH after surgery in horses with SI lesions
What are the risk factors in horses?
- SI lesions
- Prolonged post-operative ileus
- Repeated exploratory celiotomy
- Age (HIGHER INCIDENCE IN FOALS) (link with human babies)
o <30 day old - Peritonitis and abdominal abscesses
What is the pathogenesis of adhesion formation?
- Predisposes adhesions formation: inflammation and ischemia
o *Increased fibrin deposition and decreased fibrinolysis - Coagulation cascade
What are the 2 categories of peritoneal injury that predispose to adhesions?
- Inflammation
- Ischemia
Inflammation results from
- Peritoneal trauma
- Infection
- Bacterial contamination
- Foreign material
Ischemia results from
- Strangulation lesion
- Vascular compromise (Strongylus vulgaris)
- Intestinal distention
- Tight suture placement
EXAMWhat is the key regulator FIBRINOLYSIS?
- tPa (tissue plasminogen activator)
In normal conditions: what does peritoneal fibrinolytic activity cause?
- Lysis of fibrin and fibrinous adhesion
- *lysis at 48-72hours
When are ‘permanent’ fibrous adhesions formed?
- 7-14 days after surgery
How do adhesions become a clinical problem?
- Compress or distort intestine
- Narrow intestinal lumen
- *impedes normal passage of ingesta
Fibrinous adhesions
- Rarely causes clinical problems
- Undergo fibrinolysis
o Lysis 48-72hrs
Omental adhesions: non-equine species and horses
- Develop primary to increased vascular supply
- Rarely cause clinical problems
- If in HORSES: could lead to strangulation
Fibrous adhesions
- Form inadequate fibrinolysis
- Result from ingrowth fibroblasts and endothelium
- *cause clinical signs: already mature and we can’t break them down
Omental adhesions: severity
- Most benign adhesion
- May entrap SI
- (take it out in horses?)
Focal fibrous adhesions: severity
- Intestine to the mesentery
- Intestine to the incision
- Intestine to the peritoneum
- Do NOT cause distortion or kinking of intestine
- May predispose to obstruction or stricture in SI
- Ex. intestine-to-intestine adhesion leading to intestinal volvulus
Steps for a focal fibrous adhesion leading to obstruction?
- Cause distortion of mesentery or intestine
- Sharp convolutions
- Impeded flow ingesta
- Cause obstruction
What happens if you have adhesive fibrous bands between intestinal loops or between intestine and mesentery?
- Incarcerate SI
Massive fibrous adhesions: severity
- Most severe form
- b/w multiple loops of SI
What are the primary objective to prevent adhesions?
- Minimize peritoneal and serosal inflammation
- Maintain or enhance fibrinolysis
- Mechanically separate adhesiogenic surfaces
- Stimulate intestinal motility
- *prevent therapy should begin at surgery and continued for 3-4 days post-operatively
What are some important intra-operative considerations to prevent adhesions?
- Meticulous aseptic surgical technique
- Halstead’s principles of surgery
- Starch gloves
- Keep bowel moist
What is the most important principle to prevent adhesions?
- Meticulous aseptic surgical technique (intra-operative)
What are Halsted’s principles of surgery?
- Gentle handling of tissue
- Meticulous hemostasis
- Removal of damaged tissue
- Minimize exposure suture
- Minimize surgical time
Starch powder gloves
- Cause peritoneal inflammation
- Enhance post-operative adhesion formation
- *RINSE surgical gloves with sterile fluid (saline solution)
Keep bowel moist
- Avoid drying of serosa
o Continuous lavage
o Warm sterile isotonic fluid
o Prevents desiccation
Anastomotic technique: perianastomotic adhesion formation
- Mucosal exposure
- Leakage at anastomosis
- Suture exposure
Intra-operative abdominal lavage
- Sterile isotonic solutions
o Saline solution
o Lactated ringers solution - Removal of blood, fibrin, and inflammatory mediators
- DECREASE adhesion formation
o Hydroflotation
If doing a contaminated procedures what should you do at end of surgery to reduce contamination and amount of fibrin?
- 10L of sterile saline
What are some examples of protective tissue coating solutions?
- Mechanical lubricating barrier (serosal and peritoneal surfaces)
- Application of viscous solution (serosal surfaces and before manipulation)
- High-molecular-weight viscous polymer solution (ex. 1% sodium carboxymethylcellulose)
1% sodium carboxymethylcellulose (“belly jelly”)
- Most commonly used
- Cheaper
- 1-2L for a 450kg horse
- ‘siliconizing’ effect on bowel
Omentectomy
- Controversial
- Omental adhesions can cause abdominal pain
o Tension of mesentery
o Serve focus intestinal obstruction/strangulation
Post-operative: abdominal lavage
- Hydroflotation effect
o Seperates intestinal serosal surfaces
o Remove inflammatory mediators
o Remove peritoneal fibrin - Ex. pezzar catheter or indwelling chest tube
Post-operative: abdominal drain
- Drain placed at surgery
- Drain placed standing
- 10L LRS
- Lavage performed at: 12, 24 and 36 hours
What are some pharmacologic adhesion interventions?
- Broad spectrum antibiotics
- NSAIDs: flunixin
- DMSO
- Ex. heparin
Heparin
- Acts as anticoagulant via antithrombin III
o Minimize fibrin - Enhances fibrinolysis (increased tPA)
- Systemic administration (decreased PCV in horses)
How can you prevent post-operative ileus?
- Stimulate intestinal motility
- Prokinetic agents
o Lidocaine CRI (stimulates motility and is an anti-inflammatory and analgesic)
o Erythromycin
o Metoclopramide
o Bethanechol
What happens with less severe adhesions? How do you treat it?
- Recurrent colic
- Managed medically: flunixin
- Low-residue diets
o Pelleted rations
o Grazing
Severe restrictive adhesions: treatment
- Intestinal obstruction
- Strangulation lesion
- Repeated celiotomy
- Euthanasia
What are some surgical treatments of adhesions?
- Removal of devitalized intestine
o Establish functional passage of intestinal contents - Adhesiolysis: breakdown of adhesions
Adhesiolysis
- Risk of new adhesion formation: “de novo adhesions”
- Resection potential adhesiogenic tissues
- May need to do an intestinal bypass
