General Considerations

• By definition: protrusion of abdominal structures through the abdominal wall containing (1) an opening in the abdominal wall, and (2) a hernia sac consisting of  abdominal contents enclosed by peritoneum
• Majority of abdominal hernias in adults that are acquired are iatrogenic (surgery)
• Inguinal hernias are most common, mostly indirect type
• High male to female ratio for inguinal hernias

Types

Groin (pelvic) hernias

• Indirect inguinal hernia
• Through inguinal canal extending into scrotal sac (in males)
• Lateral to inferior epigastric vessels
• Most common
• Failure of obliteration of processus vaginalis
• Bilateral 20% of time
• Direct inguinal hernia
• Acquired defect in transversalis fascia of Hesselbach triangle
• Medial to inferior epigastric vessels
• More common in middle-aged males
• Femoral hernia
• Through the femoral canal medial to the femoral vein
• Only 4% of groin hernias (versus 96% inguinal)
• More often in females but still less common than inguinal hernias
• Right side more often than left
• Frequently incarcerated

Ventral (abdominal wall) hernias

• Umbilical hernia
• Failure of closure of the umbilical ring in children
• More females than males in adults
• More common in African Americans
• Incarceration is rare in children, more common in adults
• After infancy, second spike in incidence is in middle-age and result of
• Increased intra-abdominal pressure
• Paraumbilical hernia
• Adults
• Occurs adjacent to site of umbilicus
• Superior to umbilicus called epigastric (more common)
• Inferior to umbilicus called hypogastric
• Occur along the linea alba
• Usually contain fat
• Richter hernia
• Involves only anti-mesenteric side of bowel entering hernia
• Usually no obstructive symptoms
• Can occur with any of the abdominal hernias
• Incisional hernia
• Breakdown in fascia closing prior abdominal surgery
• More common with obesity, wound infection and smokers
• Usually occur within first few months after surgery
• Can be quite large and are frequently incarcerated
• Spigelian hernia
• Lateral edge of rectus muscle at semilunar line
• Inferior and lateral to umbilicus
• Rare
• Over age 50
• Obturator hernia
• Passes through obturator foramen between pectineus and obturator muscles
• Much more common in females, usually elderly
• More often on right side
• Frequently obstructs

Clinical Findings

• Fullness at site of hernia
• Symptoms of bowel obstruction
• Nausea and vomiting
• Symptoms of bowel ischemia
• Toxic

Imaging Findings

• Bowel loops projecting into scrotum or over obturator foramen on conventional radiographs
• Bowel and/or omentum (fat) or sometimes visceral organs protruding through peritoneum
• Bowel or fat in hernia sac
• Stranding of fat suggest the possibility of incarceration
• Proximal bowel dilatation from obstruction
• Bowel wall thickening, extraluminal fluid,  severe fat stranding and engorged mesenteric vessels suggest strangulation

Differential Diagnosis

• Soft tissue tumors
• Lymphadenopathy

Treatment

• Surgery for incarceration
• Inguinal hernias are usually repaired to prevent incarceration and obstruction
• Spigelian and obturator hernias are usually repaired before they become symptomatic

Complications

• Obstruction
• Ischemic and/or necrotic bowel
• Perforation