Soft Tissue Surgery: Hernias Flashcards
What is a hernia?
How are they classified?
A full thickness defect in an anatomical structure
* internal- within body- diaphragm
* external- body wall- umbilical
* True- enlargment of normal opening
* False- due to trauma or rupture
* Spontaneous- congenital
* Acquired- trauma/surgery
* Reducible
* Strangulates
What 3 problems can hernias cause?
Loss of domain
* If substantial volume ot the viscera herniates the abdominal wall adapts to lower volume (contracts)
* Closing defect without reducing tension can increased intra-abdominal pressure
* Reduced organ perfusion, reduced ventilation
Incarceration
* small and inelastic ring can trap herniated organs
* Strangulation
Strangulation
* Constriction of organs blood at the ring
* Torsion of blood vessels- more common
Why should strangulated organs be resected en bloc then release of the constricting ring?
Would cause release of vasoactive substances from necrosis etc
Decompensation and death
What is the aetiology of umbilical hernias?
What are the clinical signs?
Aetiology
* Lateral folds fail to fuse in the ventral midline during foetal development
* Inherited
CS
* Soft, round swelling at the umbilicus
* May be firm or hard if fat
What are the two types of acquired inguinal hernias?
Middle-aged intact female dogs- overrepresented
Direct
* viscera pass through inguinal canal alongside vaginal process
* Usually large and do not cause incarceration or strangulation
Indirect
* Viscera pass through the inguinal canal inside the vaginal process- more common and more likely strangluation
What is the aetiology of inguinal hernias?
- Heritable
- Short length of inguinal canal
- Oestrogen may lead to weakening
- Malnutrition or catabolic disease
- Obesity- increased intraabdominal pressure
What are the clinical signs of inguinal hernias?
- Unilateral or bilateral (RHS)
- Soft painless mass over the inguinal area
- Painful or hard
- Large hernias- bladder, uterus, intestine
- What is an indirect inguinal hernia in a dog?
- What is the aetiology?
- What is the clinical sign?
- Scrotal hernia
- Congenital defect in inguinal ring, trauma or cryptorchisism
- Unilateral pain or swelling- incarceration/strangulation are more common
What causes incisional hernias?
Dehisence of surgical abdominal wound
* Increased abdominal pressure- obesity, effusion, pregnancy, organ enlargment
* Poor holding strength- inappropriate suture, poor knot, not enough tissue, delayed wound healing
What clinical signs can diaphramatic hernias cause?
- Resp- dys/tachpnoea, coughing
- GI- anorxia, polyphagia, vomiting, diarrhoea, hepatic enceph
- CV- RCHF
- What are the most common causes of traumatic diahpragmatic hernias?
- What are the clinical signs?
- Blunt truama- RTA, fall, kicks
- May be acute or weeks after trauma- dyspnoea, excercise intolerant
What is the aetiology of perineal hernias?
- Weakness or seperation of the components of the pelvic diaphragm
- Allows herniation of abdominal/pelvic contents into the perineum and deviation and dilation of the rectum
- Inherited
- androgens weaken pelvid diaphragm muscles
- Persitent straining
- Myopathy
What are the clinical signs of perineal hernia?
- Unilateral or bilateral perineal swelling
- Reddening, oedema and ulceration of perineum
- Faecal tenesmus
- Constipation
- Flatulence
- Faecal incontinence
- Altered tail carriage
- Bladder retroflexion
What are the indications of hernia repair?
- Hernia is symptomatic
- Significant protrusion affecting QoL
- Significant risk of organ incarceration
What are the goals of hernia repair?
- Ensure any entrapped contents remain viable
- Release and return viable contents to original location
- Obliteration of redundant sac
- tension free and secure closure
