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
What are the different approaches to hernias?
- Direct approach- used for uncomplicated without evidence of obstruction/strangulation
- Ventral midline incision ± coeliotomy- bilateral hernias, internal hernias, traumatic, strangluated
What are the complications of hernia repair?
Surgical- normal surgery
* anaesthesia
* Haemorrhage
* tension
* poor tissue strength
Early post op complications
* Seroma
* Dermatitis
* Infectoion
* Wound dehiscence
* Pain
Late post op complications
* Sinus tracts
* Recurrence
How are umbilial hernias treated?
Neuter- prevent breeding
Small- 2-3mm may spontaneously close
Surgically repair
* Incisde skin of base
* Dissect sac free
* release adhesions
* enlarge ring and allow reduction of contents
* Debride ring and close primarily
What are the two surgical approaches to inguinal hernias?
- Incision over hernia parallel to the flank for uncomplicated
- Ventral midline incision ± coeliotomy- bilateral and complicated
Midline approach allows abdominal exploration
* Expose the sac
* reduce the hernia and ligate and amptuate the sac as close to the internal inguinal ring
* Close external inguinal ring with monofilament absorbable or nonabsorbable sutures
* Polyethylene mesh
* Closed suction frain if required
How should traumatic hernias be treated?
- Stabilise patient
- Ideally wait few days
- Unless cannot stabilise
Sx
* Approach acute by ventral midline ceoliotomy to allow abdominal exploratoin
* Debride devascularies/necrotic tissues
* Repair muscle layers individually
* Close hernia- depends on tissue truama, size etc
How are incisional hernias diagnosed?
- Manipulate skin suture line from side to side while performing deep palpation
- Radiography, US
How are actue incisional hernias treated?
- Support until surgery performed
- Approach uncomplicated over the original incision
- Complicated by ventral midline coeliotomy
- Debrive devitalized tissue and fat along the wound edges- not fasia/muscle
- Close primarily- include an appropriate amount of fascia
How are chronic incisional hernias treated?
- May be managed conservatively if no sign of incarceration
- Surgically repaired by approach over original incision
- Edge of the ring debrided for apposition
How is evisceration treated?
Emergency
* Cover with sterile dressing
* Elizabethan collar
* Stabilise with fluids, ABs
* Stable- induce
* Explore abdomen thoroughly- isolate damaged viscera with abdominal swabs and resect or repair as required
* Submit samples for C&S
* Lavage with isotonic fluid
* Close the abdominal wall- closed suction drain
How can diaphragmatic hernias be diagnosed?
- Presence of sternal, costal arch or abdominal wall defects suggests a diaphragmatic hernia
- ECG- low-amp complexes
- Thoracic radiographs- enlarged, rounded or ovoid cardiac silhouette
- CT
- US
How are congenital diahpragmatic hernias treated?
- Conservative in asymptomatic
- Reduce the herniated viscera into the abdomen
- Rpeiar
- Close primary defect
- Drain pericardiacl sac
How are traumatic diaphragmatic hernias diagnosed and treated?
Dx
* tucked up abdomen
* muffled heart sounds
* Borborygmi in the thorax
* Radiographs
* US
Sx
* Stabilisation
* Consider referral
How are perineal hernias diagnosed and treated?
Dx
* Rectal- loss of normal pelvic diaphragm, presence of herniated viscera
* Abdominal radiographs and lower urinary tract contrast study- bladder retroflexion
* US
Tx
* High fibre diet
* Stool softeners
* Surgical- internal obturator transposition
