Hernias Flashcards
What is a hernia?
Protrusion of an organ through a defect or opening in the wall of the anatomic cavity which it is normally contained
Hernias can be traumatic/Acquired or congenital where is the defect in those two creating the hernia?
Traumatic/Acquired:
- abdominal
- incisional
- diaphragmatic
-> defect created at origin/insertion of body wall muscles
Congenital:
- umbilical
- inguinal
- scrotal
- femoral
- peritoneal-pericardial diaphragmatic
- hiatal
-> defect in normal anatomic opening of the abdominal wall
What are the 3 parts of a hernia?
- The ring - defect in the wall
- The sac - peritoneum lining the hernia contents
- Contents - organs or tissue that has moved into the hernia ring
What is a true hernia and what is a false hernia?
True hernia: with peritoneal lining
False hernia: no peritoneal lining
Reducible or non-reducible contents - what do both of these mean?
Reducible: abdominal contents can be pushed back into abdominal cavity
Non-reducible:
-> Incarcerated - adhesions have formed which prevents reduction
-> Strangulated - blood supply to a herniated organ is compromised (size of ring plays a role)
What are the signs of an uncomplicated and a complicated hernia?
Uncomplicated hernia:
- Non painful
- Reducible vs. non-reducible
Complicated hernia:
- Congenital: painful
- Traumatic: local tissue swelling and inflammation, may not be evident immediately after trauma (no contents yet)
What are the muscles that “make” the abdominal wall?
External abdominal oblique
Internal abdominal oblique
Transverse abdominal
Rectus abdominis
Which 3 muscles/structures make up the internal inguinal ring?
internal abdominal oblique
inguinal ligament
rectus abdominis
What makes up the external inguinal ring?
The longitudinal slit in aponeurosis of the external abdominal oblique muscle
Which structures go through the inguinal canal?
- Genital branch of genitofemoral a. v. n.
- External pudendal vessel
- Spermatic cord (males)
- Round ligament (females)
When doing surgery have to leave some space open for these structures to come out.
What is a very common congenital hernia?
Umbilical hernia
-> through umbilical ring (umbilical vessels, vitelline duct, stalk of allantois
-> Flaw in embryogenesis - heritable
What are the signs of an umbilical hernia?
- unnoticed
- soft ventral abdominal masses at umbilical scar
- ring may close as late as 6 months
- rarely intestine may herniate (size dependant)
What are the key points for a surgical repair of an umbilical hernia?
- Incision avoiding hernia contents
- amputate hernia sac (peritoneal lining)
- reduce contents
- do at the same time as spay/castrate
- close external rectus sheath
What is the differentiation between a direct and an indirect scrotal/inguinal hernia?
Indirect (scrotal) -> content comes out of inguinal canal and down the vaginal process into the scrotal sac
Direct (inguinal) -> comes outside of that inguinal ring and sits directly underneath the skin (doesn’t go down vaginal process)
Where should the incision be made if we are performing surgery on an inguinal hernia? which suture material and suture pattern should be used to close?
Midline incision - next to hernia (not straight over hernia!)
best to use non-absorbable suture such as prolene, horizontal mattress suture for tension relief! remember to leave enough room for artery and vein when making inguinal ring smaller.
Is a scrotal hernia a direct or indirect inguinal hernia?
Indirect inguinal hernia
Pre-pubic tendon rupture, paracostal and dorsolateral abdomen hernias are most commonly which type of abdominal wall hernias?
traumatic through either blunt trauma or bite wounds
How do we diagnose traumatic abdominal wall hernias?
-> Abdominal radiographs
- free intra-abdominal gas (penetrating wound vs perforated GI tract)
- Discontinuous abdominal wall
-> Ultrasound
- Evaluate soft tissue swelling
Important to evaluate other concurrent injuries (traumatic hernias) - CT scan!
What is most important in the treatment of traumatic abdominal wall hernias?
Life threatening conditions take priority -> Stabilise before surgery!
Delay surgery 3-5 days, wait for inflammation to reside and for tissue to strengthen = better repair!
Emergency surgery is indicated if the animal cannot be adequately stabilised due to hernia, if the herniated organs are progressively turgid or incarcerated, or penetrating wounds explored after emergency resuscitation
How do we treat acute hernias?
- Ventral midline celiotomy
- Full abdominal exploration
- Intra-abdominal repair
Herniorrhaphy
1. Ensure viability of entrapped hernia contents
2. Reduce and return viable hernia contents
3. Obliterate redundant hernia sac/space (drain)
4. Provide tension free and secure primary closure using strong healthy tissue
Which suture material and pattern do we use when closing a herniorrhaphy?
Monofilament non-absorbable or absorbable
- simple continuous +/- tension relieving sutures (horizontal mattress)
Which complications can occur with a herniorrhaphy?
-> Related to the amount and type of tissue traumatised
- Seromas, haematomas, infection (wound drainage, culture)
- Skin dehiscence is common with bite wounds (hernia failure not common)
- Recurrence (uncommon provided appropriate technique is used and proper post operative care given)
- Prognosis is excellent - depending on concurrent injuries
Which is the most common thoracic traumatic hernia?
Traumatic diaphragmatic hernia
- blunt force, car accidents
- mechanism of injury through sudden increase in intra-abdominal pressure with the glottis open
How do we diagnose a traumatic diaphragmatic hernia?
Thoracic radiographs!
- partial loss of the normal line of the diaphragm 97% of cases (not diagnostic alone)
- obscured or displaced cardiac shadow
- abdominal viscera within the thoracic cavity
- cranial displacement of pylorus or duodenum
Ultrasound
- pleural effusion, may not detect rent in diaphragm
CT
What is important to consider before performing surgery on patients with a traumatic diaphragmatic hernia?
The longer we can wait for surgical intervention in these patients the better. Perform surgery in a stable patient (earliest opportunity)
Stabilisation of shock or pulmonary contusions.
What is a re-expansion (reperfusion) pulmonary oedema in chronic diaphragmatic hernia cases?
Inflammatory response to lung re-expansion - results in increased capillary permeability
- progressive dyspnoea, frothy sputum
- prevention is key!
- low pressure ventilation
- slow re expansion of lungs
Herniorrhaphy of a traumatic diaphragmatic hernia which suture material, size and pattern do we use?
- Debride sparingly
- Some interrupted then follow on with a continuous pattern - minimise suture material, fewer stiff cut ends
- use 2/0 Prolene - non absorbable (tissue needs longer to heal) PDS can also be used.
What should be included in the post operative care after a diaphragmatic hernia repair?
- Assess heart rate, respiratory rate and
respiratory character - Mucous membrane colour and capillary refill time
- Thoracic drain (negative pressure)
- Prophylactic antibiotics (liver herniation, perforation of GI tract)
What could be some causes of why a patient isn’t breathing well after a diaphragmatic hernia repair?
- Still air left (still a pneumothorax) - chest x-ray can help identify to drain rest of air
- Too much pain relief/narcotics
- Pleural effusion
- Tight thoracic bandage
What is a congenital PPDH?
Peritoneo Pericardial Diaphragmatic Hernia
-> Communication between abdomen and pericardial sac (fusion defect on the diaphragm)
What are concurrent defects with a congenital PPDH?
- Sternal defects
- Cranial midline abdominal wall hernia
- Umbilical hernia
- Intracardiac defects (VSD)
What are the clinical signs of PPDH?
- Few clinical signs for years (incidental finding?)
- Consequences similar to traumatic diaphragmatic hernias
- Cardiac tamponade (right sides HF)
- Weimaraner’s and Cocker spaniels
How do we diagnose congenital PPDH?
Thoracic radiographs!
- enlarged cardiac silhouette
- dorsal elevation of trachea
- overlap of heart & diaphragmatic borders
- discontinuity of diaphragm
- gas-filled structures in pericardial sac
- +/- sternal defects
In which breeds of dogs are hiatal hernias common?
Brachycephalics, Shar peis, Bulldogs
Which type of hiatal hernia is most common?
Type 1 (sliding) - where the gastroesophageal junction and the gastric fundus move into the chest cavity
What are the clinical signs of a hiatal hernia?
-> Regurgitation
-> Oesophagitis and megaoesophagus
-> Vomiting, hematemesis, anorexia, weight loss
-> Poor BCS
How do we diagnose a sliding hiatal hernia?
Difficult to capture!
- video fluoroscopy
- radiographs
- endoscopy
How does a sliding hiatal hernia develop?
Develops secondary to oesophageal hiatal rim malformation - diaphragm never closes around oesophagus, always an enlarged opening
Which are the muscles that are very important in maintaining food within the stomach? (they are part of the lower oesophageal sphincter that squeezes around oesophagus to keep food in)
Right and left pars lumbalis muscles
In dogs with oesophageal hiatal rim malformation, the pars lumbalis doesn’t sit nice and close around the oesophagus - has an extremely enlarged opening.
What should be included in the post operative care after a hiatal herniorrhaphy?
-> Gastrointestinal support - focus on gastro oesophageal junction which is the barrier against reflux (anaesthetic drugs reduce tone of junction even more)
- Metoclopramide - prokinetic (for any brachycephalic dog under anaesthesia!!)
- Erythromycin (increases lower oesophageal sphincter pressure)
- Omeprazole (proton pump inhibitor)
- Maropitant (if nauseous)
-> Aspiration risks in brachycephalics
- sensitive diet under close supervision (meatball diet)
-> Prepare owners - longer recovery period (2 weeks), regurgitation gets worse before it gets better
