2.2 Abdominal Wall Hernias Flashcards
What is a hernia?
A hernia is a protrusion of part of the abdominal contents beyond the normal confines of the abdominal wall
What are the signs and symptoms of a non-incarcerated hernia?
Fullness or swelling
Gets larger when intra abdominal pressure increases (sneezing)
Aches
What are the signs and symptoms of an incarcerated hernia?
Pain
Cannot be moved
Nausea/vomiting
Systemic problems if bowel has become ischaemic
What are causes of abdominal hernias?
Weakness in containing cavity - congenitally related, post surgery where wounds have not healed adequately, normal points of weakness
Anything that increases intra-abdominal pressure - obesity, weightlifting, chronic constipation/coughing
What is an incisional hernia?
hernia that occurs through a previously made incision in the abdominal wall, ie the scar left from a previous surgical operation
What are the 3 parts of a hernia?
- The sac - pouch of peritoneum
- Contents of the sac - any structure found within the abdominal cavity that is within the sac. Commonly loops of bowel/omentum
- Coverings of the sac - layers of the abdominal wall that the hernia has passed through.
What are the 4 main types of hernias?
- Inguinal canal
- Femoral canal
- Umbilicus
- Previous incisions
What is the inguinal canal?
Oblique passage through lower part of the abdominal wall
• In males = Structures pass through from abdomen to testis
• In Females = Round ligament goes from Uterus to labium majus
When do testis descend?
In the 7th to 8th month
What is the processus vaginalis?
An out pouching of peritoneum
What is the gubernaculum?
Condensed band of mesenchyme that links inferior portion of testis (gonad) to labioscrotal swelling ( genital swellings)
What is an incarcerated hernia?
When the contents of the sac (usually bowel) gets stuck outside the containing cavity. Contents cannot be reduced?
What is meant by reducing a hernia?
Pushing the contents back into the containing cavity. Cannot be done in an incarcerated hernia
Why is an incarcerated hernia more concerning than an ordinary hernia?
As can disrupt venous drainage from contents. Contents swells. Arterial blood flow disrupted. Areas of the bowel can become ischaemic and then necrotic. Bowel can perforate and cause peritonitis
Why are males more likely to get inguinal hernias?
Due to the descent of the testis through the inguinal canal, if processes vaginalis does not obliterate then an open channel between the peritoneal cavity and scrotum persists. Hernias can descend into the testis.
What is the tunica vaginalis?
A remnant of the processus vaginalis that surrounds the testis in the scrotum
What is a hydrocele?
A collection of serous fluid within the tunica vaginalis. The congenital form is most commonly due to a failure of the processus vaginalis to close. Adult hydrocele is often associated with inflammation or trauma and rarely, testicular tumors.
What forms the inguinal ligament?
The thickened inferior aspect of the external oblique muscle.
What is the conjoint tendon?
The structure formed from the lower part of the common aponeurosis of the internal oblique muscle and the transversus abdominis as it inserts into the crest of the pubis and pectineal line immediately behind the superficial inguinal ring.
What are the boundaries of the inguinal canal?
Inferior/floor = inguinal ligament
Anterior = aponeurosis of external oblique
Roof = transversalis fascia ( internal oblique / transversalis abdominus)
Posterior wall = transversalis fascia
What is the deep inguinal ring?
deep inguinal ring is located just above the midpoint of the inguinal ligament and lateral to the epigastric vessels. The deep ring is formed by the transversalis fascia which provides the posterior covering of the contents of the inguinal ring.
What is the lacunar ligament?
A medial triangular extension of the inguinal ligament that inserts into the pectineal line
What is the pectineal line?
The pectineal line of the pubis is a ridge on the superior ramus of the pubic bone. It forms part of the pelvic brim
What is the superficial inguinal ring?
Formed by the aponeurosis of the external oblique on the anterior of the inguinal canal. Located medially above the pubic tubercle. Where inguinal hernias protrude.
What are the 2 different type of inguinal hernias?
Direct inguinal hernia
Indirect inguinal hernia
What is the most common type of hernia?
Indirect inguinal hernia (followed by direct)
Describe the path of an indirect inguinal hernia
- Passes through the deep Inguinal ring
- The inguinal canal
- The superficial Inguinal ring
- Then depending on where the Processus Vaginalis was obliterated can potentially descend into the scrotum
Describe the path of a direct inguinal hernia
• Bulges through Hesselbach’s triangle
◦ In the vicinity of the superficial Inguinal ring
What is the anatomical differences between direct and indirect inguinal hernias?
Direct = medial to the inferior epigastric vessels Indirect = lateral to the inferior epigastric vessels
What patients more commonly get femoral hernias?
Females - due to different pelvic anatomy meaning entrance to the femoral canal in females is wider
What patients commonly get umbilical hernias?
Commonly found in infants. Most will close by age 3 (89-90%)
African descent
Low birthweight
What is a para-umbilical hernia?
An umbilical hernia acquired as an adult. Goes through linea alba at the region of the umbilicus.
Who is most at risk of getting a paraumbilical hernia?
Females
Obese patients
What hernias are prone to incarceration?
Femoral hernias
Para-umbilical
What is a strangulated hernia?
Blood supply is disrupted - can lead to tissue necrosis. Often follows incarcerated hernia
What are the borders of hasselbach’s triangle?
Medial = lateral abdominus rectus Inferior = inguinal ligament Supero-lateral = inferior epigastric vessels
What determines the degree of herniation of an indirect inguinal hernia?
Level of obliteration of processus vaginalis
How is location of herniation decribed?
Based on where the hernia leaves its containing cavity.
What are the borders of the femoral canal?
Superior = inguinal ligament Medial = adductor longus Lateral = medial border of sartorius
Where is a lump felt in a femoral hernia?
Saphenous opening
Describe the path of a femoral hernia
- travel inferior to the inguinal ligament via the femoral ring
- travel medially to the femoral vein and laterally to the lacunar ligament
- descend in femoral canal
- saphenous opening
Why are femoral hernias more concerning than inguinal hernias?
More likely to become strangulated as femoral ring is narrow
How can an incarcerated hernia become strangulated?
- hernia becomes incarcerated
- venous drainage occluded. Arterial pressure is greater than venous pressure so blood accumulates in the incarcerated hernia
- swelling
- blood supply compromised - pressure builds as blood accumulates, arterial pressure overcome
- ischaemic
- strangulated hernia
- necrosis - break down of tissue contents of hernia
Describe the path of an umbilical hernia
Hernia goes through umbilical ring
Umbilical cord passes through (should normally close at birth but may remain patent)
What does the umbilical cord consist of?
Umbilical veins, umbilical arteries, Vitelline duct, Allantois duct
How are umbilical hernias usually treated?
Usually left - painless, unlikely to have incarceration or strangulation and most close by 3-4 years of age
If problematic, surgery is very effective
What are risk factors of incisional hernias?
Previous surgery (x2 risk in emergency surgery) Obesity Midline incision Wound infection Advancing age Pregnancy Pre-op chemo
What are the 5 common incisions?
Midline incision Paramedian Gridiron Pfannenstiel Kocher
What is a midline incision?
An incision through the linea alba that avoids the umbilicus
What are the pros and cons of a midline incision?
Pros: Midline is relatively avascular which is useful during surgery, extendable so can increase operative filed if needed
Cons: Very painful post op
What are the pros of a paramedian incision?
Poor cosmetics
Can damage nerve/structures (falciform ligament/nerve supply to rectus muscles)
What is a paramedian incision?
An incision of the abdomen made on the lateral side of the rectus abdominus muscles, parallel to the midline
Where is a gridiron incision done?
2/3 of the way laterally between the umbilicus and ASIS
When is a gridiron incision commonly done?
Appendicectomy
What is a pfannenstiel incision?
A horizontal incision made below to umbilicus.
When is a pfannenstiel incision used?
Obstetrics and urology
- access gravid uterus
Where is a kocher incision?
Parallel to subcostal margin
When is a kocher used?
In an open cholecystectomy - removing the gallbladder
