Hernias Flashcards
What is a hernia? What is the difference between an external and internal hernia?
protrusion of a tissue or organ through a defect in the wall of the anatomical cavity in which it normally lies
- EXTERNAL = defect in external wall of the abdomen allows protrusion of abdominal contents
- INTERNAL = through a ring of tissue confined within the abdomen or thorax
What is the difference between true and false hernias? How do traumatic hernias commonly start?
- TRUE = anatomical hernia with a peritoneal sac
- FALSE = lack of hernial sac with protrusion of organs outside of normal abdominal opening
initially false hernias that tear through the body wall and eventually develop a sac
What are the 3 most common internal locations of hernias?
- diaphragmatic
- hiatal
- intercostal
What are the 8 most common external anatomical locations of hernias?
- paracostal
- dorsal lateral
- inguinal
- cranial pubic ligament rupture (prepubic)
- femoral
- umbilical
- ventral
- scrotal
(+ intercostal)
What is omphalocele?
large neonatal defect of the abdominal wall resulting in the intestines, liver, and other organs (covered in amniotic tissue) sticking outside through the umbilicus
- grave prognosis - outside during fetal development and compartment syndrome makes it hard to place organs in their normal positiongs
How are hernias diagnosed?
- Hx: usually just swelling, unless strangulation is present
- PE and palpation
- radiograph shows organs within the SQ
- ultrasound - intestine vs. fat vs. lipoma
- advanced imaging - CT
What is an incarcerated hernia? What do they commonly lead to?
contents are irreducible and trapped
strangulation - ischemia, tissue death
What is a strangulated hernia?
blood supply of the organs stuck in the hernia becomes compromised, leading to ischemia and necrosis —> requires emergency surgical correction
What sized hernias are the most dangerous?
small - more likely to strangulate organs that make it through
(large hernias allow free movement of organs in and out)
What is loss of domain?
chronic hernias result in compartment syndrome due to constricted abdominal muscles making the normal location too small to accomodate reduced contents
What is compartment syndrome? What does it commonly result in?
increase in pressure within a compartment that results in a restriction of the blood flow to the area
tissue death due to ischemia and free radical formation
What are the 4 principles of herniorrhaphy?
- return contents to the normal location
- secure ring closure
- tension-free closure
- utilize patient tissues
What suture material is preferred for herniorrhaphy? What can also be used?
non-absorbable nylon - lasts longer
absorbable PDS
How is an open herniorrhaphy performed?
- hernial sac is incised and removed
- edges are freshened by removing the hernial ring
How is a closed herniorrhaphy performed?
- invert sac and contents without opening the hernial sac
- freshening edges by removing the hernial ring is NOT necessary and avoided if possible
What is an umbilical hernia? When is strangulation or obstruction suspected?
true hernia due to the failure of fusion of rectus abdominus muscle at the umbilicus that may close spontaneously around 6 months
if the umbilical sac is irreducible and warm/painful
What breeds have a predisposition for umbilical hernias? What other defects should be looked for?
- Airedales
- Pekingese
- Basenjis
- Pointers
- Weimeraners
cleft palate, cryptorchidism, cardiac
What treatment options are available for umbilical hernias?
- monitor initially, if young
- primary reconstruction
- repair when neuters or other surgeries
How is a herniorrhaphy performed for umbilical hernias? What should be done if strangulation or obstruction is present?
- reduce contents if possible
- incise directly over hernia or around base if irreducible
- open hernial sac
- excise the sac (no trimming of hernial ring)
- suture with non-absorbable or absorbable sutures
extend the defect on midline
What is the difference between congenital and acquired inguinal hernias?
CONGENITAL = younger dogs < 2 y/o, male dogs
ACQUIRED = non-traumatic, middle-aged and intact males
What are the most common inguinal hernia? What can this be mistaken as?
left unilateral —> neuter animals with it!
caudal abdominal fat pads in obese cats
What are the 4 multifactoral pathogeneses of inguinal hernias?
- genetic
- obesity
- trauma
- estrogen influence - estrogen, pregnancy
What is the difference between direct and indirect inguinal hernias?
DIRECT - outpouching of peritoneum and abdominal contents adjacent to the inguinal canal
INDIRECT - outpouching of peritoneum (vaginal process) and abdominal contentd through the inguinal canal (young males and mature females; + scrotum and intestines)
What is present in the internal and external ring of the inguinal canal?
INTERNAL - internal abdominal oblique muscle, rectus abdominus muscle, inguinal ligament
EXTERNAL - slit in the external abdominal oblique muscle
What are the 3 contents of the inguinal canal?
- spermatic cord
- genitofemoral artery, vein, nerve
- external pudendal artery and vein
What is the surgical approach to female and male inguinal hernia? How are they closed?
- FEMALE: ventral midline to correct both sides
- MALE: inguinal approach directly over hernia
one layer closure of both rings - DON’T compromise the pudendal artery and vein or genitofemoral nerve
What complications are associated with inguinal hernia repair?
- seroma
- hematoma
Inguinal hernia repair:
outpouching = peritoneal lining
What are the 3 borders of the femoral triangle? What does it contain?
- sartorius muscle
- adductor longus muscle
- inguinal ligament
femoral artery, vein, nerve
What is a scrotal hernia? What else can possibly be within it? What aid repair?
rare, unilateral, indirect hernia
palpate for bowel loops
castration
What is a femoral hernia? How is it repaired? What is commonly required post-op?
abdominal contents or fat protrude through the femoral canal, caudomedial to the femoral vessels
incise parallel to the inguinal ligament
hobbles - prevent limb abduction
What are the most common diagnostics for hernias?
- palpation
- radiography (intestines under skin)
- ultrasonography
What is the process of treating acute traumatic hernias?
- stabilize patients FIRST - repairing is not a surgical emergency unless they are incarcerated or strangulated
- evaluate patient - concurrent energy, palpate hernia, reducibility
- delay surgery to makes evaluation of tissues more reliable
What approach is preferred for treating acute hernias?
- ventral midline
- perform a complete exploration for more than one tear
- enlarge incision for better exposure to correct intraabdominal injuries
What is prepubic tendon tendon rupture associated with? How is the patient positioned?
pubic or pelvic fractures (complicate repair)
dorsal recumbency with hindlegs in frog leg position with pelvis raised on towels or sand bags
How are the surrounding body parts in prepubic tendon rupture manipulated?
- avulse rectus abdominus
- wire to pubic bone to make bone-bone healing (which is much faster)
What 2 approaches are used for chronic hernias? How does their repair compare?
- ventral midline
- direct approach over hernia
- less likelihood of other injuries
- easier to reconstruct anatomically or supplement with prosthetics
What are the difference between acute and chronic incisional hernias?
ACUTE = within 7 days of surgery (usually 3-5)
CHRONIC = weeks, months, years later
What are 5 common risk factors associated with incisional hernia develoment?
- inappropriate surgical technique* (increased fat at incision line)
- altered tissue strength
- suture failure
- patient condition
- poor owner compliance
What are the 3 differentials for incisional hernias?
- seroma/hematoma
- abscess
- exaggerated inflammatory response - granuloma due to suture materials
What are the 3 ways of treating incisional hernias?
- identify underlying cause
- culture and sensitivity if wound is open
- anatomic closure with non-absorbable suture material
What causes a perineal hernia? What 3 muscles are associated?
disruption of the pelvic diaphragm where the perineal muscles separate, causing the rectum, pelvic or abdominal contents displace perineal skin
- levator ani
- coccygeus
- anal sphincter
What animals are most affected by perineal hernias?
intact > 5 y/o males (pelvic diaphragm stronger in females)
- Boston Terrier
- Boxer
- Collies
- Corgi
- Dachshund
- OESD
- Pekingese
- Kelpi
- rare in cats, usually neutered males
What is thought to be the etiopathogenesis of perineal hernias? In cats?
associated with male hormones, straining, and congenital or acquired muscle weakness/atrophy —> prostatitis, cystitis, obstruction
idiopathic or secondary to other disease processes
What are 4 rectal abnormalities seen with perineal hernias?
- DEVIATION - full-thickness flexure (common)
- SACCULATION - full-thickness outpouching (unilateral)
- DIVERTICULUM - outpouching of rectal mucous membranes in dogs through a defect in the overlying muscle layers (mucosal bulges through muscle)
- DILATATION - full-thickness 360 enlargement (bilateral)
What are the 4 most common signs associated with perineal hernias?
- usually nonpainful, reducible perineal masses with thickness depending on contents
- tenesmus/dyschezia/fecal incontinence
- constipation
- dysuria
What are 6 common perineal hernia contents?
- retroperitoneal fat
- serous fluid
- rectum
- prostate
- urinary bladder
- small intestine
How is a perineal hernia diagnosed?
- history, PE
- RECTAL PALPATION
- radiographs
- blood work
When is a perineal hernia an emergency?
- irreducible, painful, and/or discolored swelling
- stranguria (urinary bladder within hernia causes urethral obstruction)
How can the urinary bladder found in a perineal hernia be retroflexed?
- catheterize or cystocentesis to take out urine and decrease pressure
- reduce urinary bladder
- indwell catheter until surgery
What 7 structures make up the perineum?
- external anal sphincter
- levator ani muscle
- coccygeus muscle
- rectal wall
- sacrotuberous ligament
- internal pudendal artery, vein, nerve
- internal obturator muscle
What are the 4 locations of perineal hernias?
- caudal - between levator ani, external sphincter, and internal obturator (most common)
- sciatic - between sacrotuberous ligament and coccygeus muscles
- dorsal - between levator ani and coccygeus muscles
- ventral - between ischiourethralis bulbocavernosus, and ischiocaernosus
How are perineal hernias usually treated?
conservative - dietary modification, stool softeners, enemas —> NOT persued for long-term management
What are 2 primary reconstruction options for perineal hernias? What caution needs to be taken?
- suture reconstruction
- internal obturator muscle transposition (more difficult but less tension on sutures and less deformity of the anus)
perineal nerve and vessels may be displaced from their normal position
What 3 adjunctive procedures are commonly done with perineal hernias?
- colopexy/cystopexy - prevents recurrence
- semitendinosus muscle transposition - very invasive
- implants
What muscle is most commonly affected by perineal hernias? Where are sutures placed for reconstruction?
levator ani
external anal sphincter to coccygeus muscle
How is an internal obturator muscle transposition performed?
muscle elevated dorsally and medially to reinforce the levator ani and sphincter
- increased contamination likelihood
What is recommended to treat perineal hernias following reduction?
concurrent castration - prevents/treats prostatic disease and testicular neoplasia too
- recurrence higher in noncastrated dogs
What is an advantage and disadvantages to caudal/perineal castrations?
ADVANTAGE - avoids need to reposition patient, reducing anesthesia time
DISADVANTAGES - unfamiliar technique, exposure limited compared to open castrations
What is recommended immediately following repair of a perineal hernia? Why?
perform a rectal exam while still under
assess repair and opposite side if unilateral repair
How long should medical management be continued following perineal hernia repair?
4-6 weeks
stool softeners and pain meds to decrease straining while the prostate is healing
What are 5 complications associated with perineal hernia repair?
- recurrence - technique, surgeon experience, tissue quality
- wound infection
- rectal prolapse
- sciatic neve entrapment
- fecal/urinary incontinence (damage to anal or urethral sphincters)
What are common signs associated with sciatic nerve entrapment following perineal hernia repair? How is this treated?
- marked pain
- non-weight-bearing
- lameness
- knucking
remove sutures!
