Intra-abdominal adhesions Flashcards
What are adhesions?
a type of scar tissue that forms between organs and tissue after abdominal surgery
That are the steps of adhesion?
- tissue injury
- inflammatory response
- fibrin deposition
- adhesion
What species are most likely to get adhesions?
horses
humans
What is the second most common cause for repeat celiotomy in horses after abdominal surgery?
adhesions
What is the most common reason for death after surgery in horses with intestinal lesions?
adhesions
What are risk factors associated with adhesions in horse?
- small intestinal lesions (handling!)
- prolonged post-op ileus
- repeated exploratory celiotomy
- age (higher in foal esp
What two things predispose to adhesion formation?
- inflammation
2. ischemia
What are examples of inflammation in the abdominal cavity?
- peritoneal trauma
- infection
- bacterial contamination
- foreign materia
What are examples of ischemia in the abdominal cavity?
- strangulating lesion
- vascular compromise
- intestinal distention
- tight sutures
What occurs with inflammation and necrosis in the pathogenesis of adhesion formation?
- increased fibrin deposition
2. decreased fibrinolysis
What are the two key activators to get from plasminogen to plasmin? REMEMER
- tissue plasminogen activator
2. urokinase plasminogen activator (uPA)
What pathways result in fibrin deposition?
intrinsic/extrinsic/common
What pathways result in fibrin deposition?
intrinsic/extrinsic/common
Under normal conditions, what happens to fibrin?
peritoneal fibrinolytic activity causes lysis of fibrin and adhesions within 48-72 hours
What balance is disrupted when adhesions occur?
coagulation/inflammation and fibrinolysis.
Thus fibrin deposition exeeds fibrinolysis
What occurs to fibrinous adhesions?
there is maturation and inadequate adhesions, that leads to inadequate permanent fibrous adhesions
When do permanent fibrous adhesions occur?
7-14 days after surgery
What are consequences of the formation of fibrous adhesions?
- compression or distortion of intestines, narrowing of lumen
- impedement of of normal passage of ingestion
Are fibrinous adhesions an issue?
no, they undergo fibrinolysis in 48-72hrs
Are omental adhesions a problem?
no, they can even be helpful to increase vascular supply in other species but maybe not horse.
rarely cause clinical problems–may entrap small intestine
How do fibrous adhesions form?
- Due to inadequate fibrinolysis
2. result from ingrowth of fibroblasts and endothelium
Where can focal fibrous adhesions occur?
- intestine to mesentery
- intestine to incision
- intestine to peritoneum
What are the two key activators to get from plasminogen to plasmin? REMEMER
- tissue plasminogen activator
2. urokinase plasminogen activator (uPA)
What is the most common cause of recurrent abdominal pain in horses after small intestinal surgery
adhesions
What is the 2nd most common cause of performing a repeat celiotomy after abdominal surgery?
dhesions
What is one of the most common reasons for euthanasia after surgery in horses with small intestinal lesions
adhesions
What is the most consistent clinical sign associated with abdominal adhesions in horse?
recurrent colic
What are risk factors for post-op intra-abdominal adhesions in horses?
- small intestinal lesions
- intestinal resection and anastomosis
- prolonged post-op ileus
- repeated exploratory laparotomy (celiotomy)
- age (higher incidence in foals and miniature horses than adults)
- peritonitis and abdominal abscesses
What foals are the most likely to get adhesions?
30 days old
What are the two theories of adhesion formation?
- adhesion forms in response to ischemia to supply vascular and cellular support to damaged ischemic intestine and facilitate healing
- adhesions are a detrimental process caused by inflammation and ischemia which results in depression of fibrinolysis (especially depression of tissue plasminogen activator)
What is the most important plasminogen activator? What happens to it when there is excessive fibrous adhesion formation
tissue plasminogen activator
it is depressed
What are the two categories of peritoneal injury that predispose to adhesions?
- inflammation
2. ischemia
What can inflammation result from?
- peritoneal trauma
- infection
- bacterial contamination
- foreign material
What can ischemia result from?
- strangulating lesion
- vascular compromise
- intestinal distention
- tight suture placement
How do inflammation and ischemia predispose to fibrous adhesions?
they increase fibrin deposition and decrease fibrinolysis
–>imbalance between fibrin deposition and fibrinolysis
How do inflammation and ischemia predispose to fibrous adhesions?
they increase fibrin deposition and decrease fibrinolysis
–>imbalance between fibrin deposition and fibrinolysis
What is the result of the coagulation cascade?
fibrin clot formation
What is the key regulator of fibrinolysis
tissue plasminogen activator
In the normal scenario, what happens to fibrinous adhesions?
lysis in 48-72 hours
In a situation with inadequate fibrinolysis, what happens with fibrinous adhesions?
fibroblastic migration and proliferation
permanent fibrous adhesions formation 7-10 days after surgery
What are the 3 main types of intra-abdominal adhesions?
- fibrinous
- omental
- fibrous
what is the outcome of fibrinous adhesions?
- rarely cause clinical problems
2. undergo fibrinoylsis most often
what is the outcome of fibrinous adhesions?
- rarely cause clinical problems
2. undergo fibrinolysis most often
Do omental adhesions cause problems?
rarely but can cause entrapment of the small intestine
Do fibrous adhesions cause problems?
yes
Most intra-abdominal adhesions affect what?
the small intestine
What are the different types of adhesions?
- omental adhesions (body wall or two bowel)
- focal fibrous adhesions no kinking
- focal fibrou adhesions (kinking)
- adhesive fibrous bands
- massive fibrous adhesions–most severe
What can be a problem with focal fibrous adhesions that distort the mesentery or intestine?
can impede the flow of ingesta
can provide focus for vulvulus
What can adhesive fibrous bands do?
form between bowel loops or between intestine and mesentery and cause intestinal hernias or entrapment or loops that entrap intestine
What are types of adhesions that can cause intestinal obstruction?
- fibrous intestines between intestine and omentum, mesentery, peritoneum and abdominal wall incisions
- fibrous adhesive bands that may incarcerate intestine
- adhesions between adjacent small intestinal loops
- matted adhesions involving multiple loops of small intestine
How are abdominal adhesions prevented?
- minimize peritoneal and serosal inflammation
- maintain or enhanec peritoneal fibrinolysis
- mechanically separate potential adhesiogenic surfaces
- stimulate adequate intestinal motility
what is the most important principle to prevent adhesions forming?
meticulous aspectic surgical technique (halsted principles)
What are the halsted principles?
- gentle handling
- meticulous hemostasis
- removal of damaged tissue
- minimize exposure of suture material
- minimize surgical time
What are intra-operative considerations to prevent adhesions?
- serosal surface should be kept moist
- intestinal manipulation should be atraumatic
- starch powerder on surgical glvoes incites inflammatino/adhesion–rinse with sterile fluid or use powder free
What are intra-operative considerations to prevent adhesions?
- serosal surface should be kept moist
- intestinal manipulation should be atraumatic
- starch powerder on surgical glvoes incites inflammatino/adhesion–rinse with sterile fluid or use powder free
why can anastomoses predispose to adhesion?
- mucosal exposure
- leakage
- exposure of suture material
What are 4 ways to minimize adhesions from anastamoses
- maintain proper tissue alignment
- promote optimal intestinal healing
- complete mucosal coverage
- minimal suture exposure
What are methods of separating adhesiogenic surfaces?
- intra-abdominal lavage
- post-operative abdominal lavage
- protective tissue coating solutions
- bioresorbable hyaluronate carboxymethylcellulose membrane
What is intra-abdominal lavage?
used during surgery to prevent desiccation of serosal surfaces and removal of blood fibrin and inflammatory mediators. Use sterile saline or LRS at the end
What is post-operative abdominal lavage?
decreases adhesion in horse. use a catheter or tube
What is post-operative abdominal lavage?
decreases adhesion in horse. use a catheter or tube in standing horse. 2x daily for 48 hrs
What are protective tissue coating solutions?
belly jelly
sodium hyaluronate
What is bioresorbable hyaluronate-carboxymethylcellulose membrane
Applied to serosal surface of intestine to form a temporary protective barrier
Why is an omentectomy performed?
to prevent adhesion in hrose. controversial.
What drugs have been shown to deccrease peritoneal inflammation
- broad spectrum antimicrobials
- NSAIDs
- DMSO
(penicillin, gentamicin, flunixin meglumin)
What is heparin used for in horses?
to decrease heparin formation. decreases fibrin, increases fibrinolysis by stimulating plasminogen activator
When should preventative therapy begin and how long should it be continued and why?
- begin at surgery
- go 3-4 days
- critical period for fibrinous adhesion formation and fibrinolysis
When should preventative therapy begin and how long should it be continued and why?
- begin at surgery
- go 3-4 days
- critical period for fibrinous adhesion formation and fibrinolysis
How can abdominal adhesions be treated?
surgically
What is surgical treatment of adhesions?
- adhesiolysis–not v. good
- laparoscopic adhesiolysis
- second-look laparoscopic in foals–10 days later, still fibrinous
What is the prognosis of abdominal adhesions?
poor
long term survival rates 20%
usually apparent within first 60 days of surgery