Ch.40 Abdominal Hernias Flashcards
Difference between inguinal rupture and ruptured inguinal hernia?
In an inguinal rupture the viscera protrude through a rent in the peritoneum adjacent to the vaginal ring and lie outside the vaginal process.
In a ruptured inguinal hernia, viscera enters the subcutaneous tissue through a rent in the vaginal process.
The deep inguinal ring is formed by
Cranial - Caudal edge of internal abdominal oblique
Ventromedial - Rectus abdominis m. and prepubic tendon
Caudolateral - Inguinal lig.
By what age should a small manually reducible inguinal hernia resolve in foals.
6 months
What fraction of acquired inguinal hernias affect the left side?
2/3
What is the reported success rate of manual reduction of acquired inguinal hernia?
82.5%
What is the reported % of horses requiring small intestine resection following successful manual reduction of acquired inguinal hernia?
12.5%
What direction should the vaginal ring be incised to facilitate reduction of herniated intestine and why?
Craniolateral to avoid the caudal epigastric
What size vaginal ring necessitates closure?
2 fingers or more
What size mesh in used in vaginal ring closure?
8 x 6cm
How large a flap should be made when closing the vaginal ring with a peritoneal flap?
6x10cm
What size endohernia staples are used in the peritoneal flap approach to closure of the vagina ring
4.8mm
Coverage of which aspect of the vaginal ring is critical to prevent herniation
Caudal
Hernias characterized by incarceration of only the anti mesenteric aspect of the intestine
Richters or Parietal
Only considered a true hernia if
Protrudes through a normal aperture
Protrusion of viscera through an acquired opening is called a
False hernia or rupture
Diff between true and false hernia
True
- viscera protrudes through a normal aperture
-sac is lined with peritoneum
False
- Acquired opening
- Not lined with peritoneum
Which gender are congenital umbilical hernias most prevalent in
Female
In which breeds are congenital umbilical hernia most prevalent
TB AQH
Umbilical hernias developing between which weeks are less likely to spontaneously resolve
5-8weeks
Umbilical hernias of what size may resolve spontaneously by the time the foal reaches 6-12mo
3cm or less
Elastrator rings can be used for hernias up to what size
8cm
Premature dislodgement of the hernial clamp may result in
Evisceration
Activity following herniorraphy consists of
30-60 days stall confinement with hand walking followed by 30 easy small paddock turnout
When does acute total dehiscence usually occur
In recovery
Delayed total disruption of the ventral incision usually occurs within what timeframe
3-8 days
What is used for secondary closure of a dehisced abdomen? Suture, pattern, distance between sutures and edges
18-22 gauge stainless steel wire
Through and through interrupted vertical mattress
2.5cm apart
Far - 5cm from edge of wound
Near - 2.5cm from edge of wound
When wiring an abdomen post dehiscence, which layers should the wire engage
Near - all layers minus the retroperitoneal fat and peritoneum or just skin and subcutaneous
Far - Skin, fascia and rectus abdominus
Following wiring of a dehisced abdomen for how long should the horse be confined to a stall?
60 days
Incidence of herniation after midline celiotomy
8.1-16%
When do incisional hernias usually become apparent
2-3 months post discharge from hospital
How soon after identifying an incisional hernia should a repair be attempted and why
3-4 months to allow time for local inflammation/infection to resolve and for hernial ring to mature making it more apparent and capable of holding suture
What are the 5 techniques of primary closure using mesh
1- Onlay
2- Inlay
3- Retrorectus sublay
4- Peritoneal sublay
5- Underlay
Benefit of primary closure of an incisional hernia without the use of mesh
1- Decreased risk of SSI
2- Shorter sx time
3- Cheaper
4- Eliminates risk of adhesion btw mesh and viscera
5- Shorter hospitalisation
6- Shorter return to exercise
Cons of primary closure of an incisional hernia without the use of mesh
Multiple small gaps
Up to what length and width has primary closure with suture been reported for repair of an incisional hernia
28cm long or 18cm wide
How far beyond the hernial ring is the subcutaneous tissue dissected in incisional hernia repair
4-5cm
% rate of short term complications reported in incisional hernia repair when a mesh was not used in primary closure
11%
% rate of long term complications reported in incisional hernia repair when a mesh was not used in primary closure
4%
when performing onlay mesh placement how far cranial and caudal to the hernia ring should the incision be extended
6-8cm
How much of the external sheath of the rectus abdominis m. is exposed in the onlay mesh placement
6cm
Where is the mesh placed in a rectorectus sublay technique
Between rectus abdominis m. and its internal sheath
Where is the mesh placed in a peritoneal sublay technique?
Between internal sheath of rectus abdominis and peritoneum
What complications were reported in a retrospective study of 13 horses undergoing repair of an incisional hernia with preperitoneal sublay technique
- All - Mild to moderate abd pain <24hrs post op
- All - Seroma or hematoma formation
- 8 - developed incisional drainage
- 3 - Tear of internal abdominal oblique near mesh tissue interface
Material of mesh advised for laparoscopic underlay mesh repair for incisional hernia
Poly tetra fluoro ethylene
Why use a polytetrafluoroethylene mesh
Prevents adhesion formation between the mesh and the viscera
In a report of 11 equids undergoing repair of a lateral abdominal wall hernia what was their recovery period?
2 weeks stall,
4 weeks small paddock,
Back to work 42-56 days
The prepubic tendon attaches where?
Cranial border of the pubis including iliopubic eminences
What muscles does the republic tendon serve as the tendon of insertion for?
- External sheath of rectus abdominis m.
- Gracilis m.
- Pectineus m.
Which horses most commonly experience prepubic tendon rupture
Aged draft horses during late pregnancy
Stance of mare with republic tendon rupture
Saw horse, marked lordosis, elevation of tail and tuber ischia.
How to confirm diagnosis of republic tendon rupture
Discontinuity of of abdominal wall cranial to pubis on transcutaneous ultrasound
Treatment for term or near term mares with republic tendon rupture
Induce parturition with 75IU Oxytocin in 1L saline over 1 hour
Why are diaphragmatic hernias commonly false hernias
Often lack a hernial sac
Where are acquired diaphragmatic hernias most often located?
Musculotendinous portion of the diaphragm
Where are congenital diaphragmatic hernias most often located?
Left dorsal tendons portion of the diaphragm
Causes of congenital diaphragmatic hernia?
1 - Trauma in utero
2 - Trauma in parturition
3 - Failure of the embryonic components of the diaphragm to fuse
Where is a morgagni hernia located
Retrosternal diaphragmatic hernia
Right ventral aspect of diaphragmatic musculature
How/why do (Morgagni) retrosternal diaphragmatic hernia occur
Failed fusion of the septum transversum and the pleuroperitoneal folds
What is the hernial sac of the retrosternal hernia made up of?
Peritoneum and pleura
At what age do retrosternal hernia become clinically apparent
1 year
What % of horses with diaphragmatic hernia have auscultatable borborygmi in the thorax?
80%
When repairing a diaphragmatic hernia how is the celiotomy incision extended to best visualise the lesion
Finochetto rib retractor
When performing a standing thoracoscopy to repair a diaphragmatic hernia, through which intercostal space was the scope introduced
10th
