Pathophysiology and repair of hernias

Question 1

Define a hernia

Answer 1

Full thickness defect allowing protrusion of viscera

Question 2

Hernias are made up of what 2 components?

Answer 2

Ring - border of defect

Sac - mesothelial layer covering hernia contents

Question 3

What is an incarcerated hernia?

Answer 3

Hernia tissue becomes trapped and cannot move back into place

Question 4

What is a strangulating hernia?

Answer 4

Hernia tissue becomes trapped

Blood supply is obstructed

Question 5

With strangulating hernias, which blood flow (venous or arterial) is affected first?

Answer 5

Venous drainage affected first

Followed by arterial

Question 6

What are the consequences of strangulating hernias?

Answer 6

Organ necrosis

Potential rupture and release of contents

Question 7

What causes an umbilical hernia?

Answer 7

Congenital/inherited

Incomplete fusion of ventral abdominal wall

Question 8

What is the most common abdominal hernia in small animals?

Answer 8

Umbilical hernia

Question 9

What breeds are predisposed to an umbilical hernia?

Answer 9

Weimaraner
Pointer
Airedale
Pekingese
Basenjis

Question 10

What are the 2 types of inguinal hernia?

Answer 10

Direct inguinal herniation

Indirect inguinal herniation

Question 11

What is a direct inguinal herniation?

Answer 11

Herniation through inguinal ring

ADJACENT to vaginal process

Question 12

What is an indirect inguinal herniation?

Answer 12

Hernia through inguinal ring
INTO the cavity of vaginal process
(Includes scrotal hernias)

Question 13

Are inguinal hernias spontaneous (congenital) or acquired?

Answer 13

Acquired

Question 14

What signalment (sex, neuter status, age) of animals are most likely to develop an inguinal hernia?

Answer 14

Intact females

Middle aged

Question 15

What are the risk factors for an inguinal hernia?

Answer 15

Obesity
Females (have short inguinal canal)
Oestrogen
Malnutrition/catabolic disease

Question 16

Scrotal hernias are an example of what type of herniation?

Answer 16

Indirect inguinal hernias

In male dogs

Question 17

Are scrotal hernias usually unilateral or bilateral?

Answer 17

Unilateral

Question 18

The aetiology of scrotal hernias is unknown, but is it thought to be spontaneous (congenital) or acquired?

Answer 18

Congenital - defect in inguinal ring

Question 19

What are the clinical signs of scrotal hernias?

Answer 19

Pain
Swelling of scrotum
(Incarceration/strangulation common)

Question 20

Are traumatic hernias false or true hernias?

Answer 20

False - not through normal opening

Question 21

What can cause traumatic hernias?

Answer 21

Blunt trauma:
Traction/avulsion injury to abdomen
Tearing of abdominal muscles

Question 22

What causes incisional hernias?

Answer 22

Wound dehiscence, due to:
Excess force on incision (obesity, ascites, coughing/straining)
Or poor holding strength of wound

Question 23

What are the clinical signs of an incisional hernia?

Answer 23

Wound inflammation/oedema
Swelling over/around wound
Evisceration (acute)

Question 24

What are congenital peritoneopericardial diaphragmatic hernias?

Answer 24

Midline communication between abdomen and pericardium

Question 25

What causes peritoneopericardial diaphragmatic hernias?

Answer 25

Failure of transverse septum to fuse

Question 26

What are the sequelae of peritoneopericardial diaphragmatic hernias?

Answer 26

Pulmonary compression | Pericardial effusion and tamponade (compression of heart)

Question 27

What are the clinical signs of peritoneopericardial diaphragmatic hernias?

Answer 27

Respiratory signs GI signs Right sided heart failure (due to tamponade) May be asymptomatic/incidental finding

Question 28

What can cause traumatic diaphragmatic hernias?

Answer 28

Blunt trauma with glottis open (increased pressure causes muscle tear) Iatrogenic due to sharp trauma

Question 29

What is the main consequence/sequelae of traumatic diaphragmatic hernias?

Answer 29

``` Respiratory insufficiency (Due to lack of functional diaphragm, lung compression, pleural effusion etc) ```

Question 30

What are the clinical signs of traumatic diaphragmatic hernias? Do they present straight away?

Answer 30

May present several weeks after trauma Dyspnoea, exercise intolerance Abnormal stance - head extended, elbows abducted Lethargy, weight loss, difficulty lying down

Question 31

What causes perineal hernias?

Answer 31

Weakness/separation of pelvic diaphragm

Question 32

What muscles make up the pelvic diaphragm (4)?

Answer 32

Coccygeus Rectococcygeus Levator ani External anal sphincter

Question 33

Perineal hernias have multiple aetiologies. Which breeds are predisposed?

Answer 33

Collies Boxer Poodle Old English Sheepdog

Question 34

Are perineal hernias more common in males or females? What age and neuter status?

Answer 34

Older intact males

Question 35

What are the clinical signs of perineal hernias?

Answer 35

``` Unilateral/bilateral swelling Erythema, oedema, ulceration of skin Faecal tenesmus, pain, constipation, incontinence, flatulence Bladder retroflexion and dysuria Altered tail carriage ```

Question 36

Some hernias do not need repairing. What indicates a hernia needs repair?

Answer 36

Symptomatic hernia - pain, inflammation, strangulation Protrusion affecting animal's QOL Risk of organ incarceration or strangulation

Question 37

What are the 2 approaches to hernia repair surgery?

Answer 37

Direct - over hernia | Ventral midline coeliotomy

Question 38

What are some complications during hernia repair surgery?

Answer 38

``` Anaesthetic complications Haemorrhage Contamination Inability to close defect Poor tissue strength around repair Loss of domain ```

Question 39

What are some complications after the hernia surgery?

Answer 39

``` Seroma/haematoma Pain Infection Dehiscenece, evisceration Sinus tracts/enterocutaneous fistulae Recurrence ```

Question 40

Older, intact males are most likely to have what type of hernia?

Answer 40

Perineal hernia

Question 41

Middle-aged, intact females are most likely to have what type of hernia?

Answer 41

Inguinal hernias