Kapitel 84 – Abdominal wall reconstruction and hernias

Question 1

What are the components of a hernia?

Answer 1

a. Ring
b. Protruding contents
c. +/- Sac (always in congenital)

Question 2

What is peritonealization?

Answer 2

Formation of a peritoneal sac over the contents of chronic traumatic or incisional hernias.

Question 3

What is auto-penetrating hernia?

Answer 3

When a traumatic abdominal hernia is caused by a fractured rib penetrating through abdominal musculature

Question 4

What are the main types of abdominal hernia (True vs False) & definition? In what situation there is always a herniated sac?

Answer 4

a. True hernia (ring confined with normal aperture in abdominal wall)- congenital or acquired

b. “False” hernia (other areas as result of trauma or disrupted surgical approach) - acquired –> Traumatic or incisional

In congenital hernias there is always a sac (vs traumatic or incisional: no sac)

Question 5

Name the hernias

Answer 5

1) Paracostal hernia
2) Dorsal lateral hernia
3) Inguinal hernia
4) Cranial pubic ligament rupture
5) Femoral hernia
6) Umbilical hernia
7) Ventral hernia
8) Scrotal hernia

Question 6

Anatomy of the abdominal wall:
- name of muscles layers?
- insertions?
- most inner layers covering muscle?

Answer 6

a. External abdominal oblique (4 to 13 ribs, TL fascia)
b. Internal Abdominal Oblique (TL fascia, Tuber coxae)
e. Rectus abdominis - stentum and costal cartilage and unites with the pectinal and prepubic tendon
c. Transversus Abdominis (8 - 13 ribs, Transverse process L1-L7, TL fascia)
d. Transverse fascia & peritoneum : cover inner surface of transversus abdominis

Question 7

List causes of abdominal hernias

Answer 7

a. genetically impaired collagen formation, deposition, organization, or degradation
b. wound healing deficiencies
c. traumatic injury
d. failed abdominal approach closures
e. disrupted hernia repairs

Question 8

What does “loss of domain” mean?

Answer 8

a. It describes a situation when the abdominal wall has become accustomed to a relatively small intraabdominal volume because of organ displacement outside the cavity (usually through a large defect).
b. Manual reduction of hernia contents and primary closure of the defect is difficult or impossible in this situation.

Question 9

Which hernias have a high risk for organ incarceration and strangulation?

Answer 9

Abdominal defects with small, inelastic hernial rings, such as scrotal or femoral hernias

Question 10

What are the main goals in hernial repair?

Answer 10

a. ensure the viability of entrapped hernia contents
b. release and return viable hernia contents into their normal location within the abdominal cavity
c. obliterate redundant hernia sac tissue
d. provide a tension-free and, if possible, secure primary closure of the defect using strong, healthy surrounding tissue.

Question 11

What is the difference between indirect and direct inguinal hernia? Which I most common?

Answer 11

Indirect inguinal hernias: the abdominal viscera enter the cavity of the vaginal process –> more common one and more often causes organ strangulation.

Direct inguinal hernias: organs pass through the inguinal rings adjacent to the normal outpouching of the vaginal process

Question 12

When does acquired inguinal hernias often occur?

Answer 12

a. During estrus or in pregnant bitches
b. (most common in intact female dogs)

Question 13

What structures make up the boarders if the internal and external inguinal rings?

Answer 13

Internal: Rectus abdominis, internal abdominal oblique muscle and inguinal ligament

External: A longitudinal slit in the aponeurosis of the external abdominal oblique muscle

Question 14

What structures has to be preserved when repairing an inguinal hernia?

Answer 14

external pudendal and genitofemoral vessels, genitofemoral nerve, and, in intact male dogs, the spermatic cord

Question 15

What is the most common complication after inguinal hernia repair?

Answer 15

Formation of seroma or hematoma

Question 16

What is the most common cause of femoral hernia?

Answer 16

most often result from blunt trauma, causing avulsion of both the pubic (prepubic hernia) and inguinal ligaments.

Question 17

Name some risk factors for acute incisional hernias

Answer 17

a. Increased abdominal pressure from pain
b. Entrapment of fat between abdominal incision edges
c. Inappropriate suture material
d. Infection
e. Chronic steroid treatment
f. Poor post-op care

Question 18

What is the optimal suture-to-wound ratio to reduce the risk of incisional hernia when closing the abdomen?

Answer 18

A 4:1 suture-to-wound ratio which equals 5-7 mm facial bites 3-4 mm apart.

Question 19

When does acute incisional hernias usually develop?

Answer 19

3-5 days after surgery

Question 20

When is nonautologous repair methods preferred?

Answer 20

a. for reconstruction after tumor resection
b. for hernia repair when primary closure is not possible
c. when the patient cannot tolerate intraperitoneal compression

Question 21

List autologous repair methods

Answer 21

a. Vacuum-Assisted Closure
b. Separation of Anatomic Components (eg. Facial releasing incision or rectus advancement techniques)
c. Abdominal Wall Partitioning
d. Muscular Flaps
i. Cranial Sartorius Muscle Flap
ii. External Abdominal Oblique Myofascial Flap
iii. Rectus Abdominis Flap

Question 22

Approximately how much can the cranial sartorius muscle flap cover?

Answer 22

30% of the abdomen if the flap is positioned transversely along the pubis, or

approximately 80% of the length between the pubis and ribs on the ipsilateral side if the flap is positioned parallel to midline

Question 23

What’s is the most widely used synthetic material used for abdominal wall replacement?

Answer 23

Polypropylene mesh

Question 24

What techniques can be used for mesh implantation? Which is the preffered technique and why?

Answer 24

a. onlay (superficial to the rectus fascia)
b. interpositional (mesh edge to fascial edge)
c. “sublay” or underlay techniques (deep to the rectus abdominis muscle). This is the preferred technique. It provides a large contact area between the mesh and abdominal wall, particularly with abdominal pressure, which creates optimal anchorage of the mesh to adjacent fascia, and it better distributes tension across the repair = lowest rate of reherniation

Question 25

What are the 5 types of muscle flap circulation and classification

Answer 25

Type I – one vascular pedicle (rectus femoris)
Type II – dominant vascular pedicles w/ minor pedicles (cranial sartorius, cervical part of trapezius)
Type III – two dominant pedicles (semitendinous)
Type IV – segmental vascular pedicles (caudal sartorius)
Type V – one dominant vascular pedicle and secondary segmental pedicles (Latissimus dorsi w/ lateral thoracic artery coming from distal when elevation of proximal part only segmental pedicles disturbed, deep pectoral)