A hernia is an abnormal protrusion of the abdominal contents through a weakness or defect along the wall of the abdomen. Hernias can be congenital or acquired.
- 5 million Americans have hernias.
- A majority of hernias are groin hernias (inguinal/ femoral).
- ⅓ of all repaired ventral hernias are incisional hernias and the remaining ⅔ are primary ventral hernias.
- Some hernias can be congenital:
- Inguinal (failure of the closure of the processus vaginalis)
- Umbilical (present at birth in all infants, but most close within the 1st 2 years of life)
- Acquired hernias are due to loss of the mechanical integrity of the abdominal wall:
- Primary: A genetic component causes weakness of the abdominal wall.
- Incisional: damage to abdominal wall muscles and fascia during surgery
- A hernia has a hernia sac: an outpouching of the peritoneum, which covers the hernia contents
- Reducible hernia:
- Contents of the hernia can freely return to the abdominal cavity.
- During an examination, the hernia can be pushed back in.
- Inability of the contents of the hernia to return to their original cavity
- Presents with severe pain and nonreducible bulge
- Symptoms of intestinal obstruction develop if intestines are incarcerated.
- Contents of the hernia are incarcerated.
- Blood supply to the incarcerated organs is compromised, causing ischemia and resultant tissue death.
Various types of abdominal wall hernias can be defined by anatomic location:
- Anterior hernia:
- Groin hernia:
- Pelvic hernia:
- Posterior hernia:
- Superior triangle (Grynfeltt hernia)
- Inferior triangle (Petit hernia)
Ventral hernias occur through a weakness in the anterior abdominal wall and can be congenital or acquired.
Layers of the abdominal wall include:
- Camper’s fascia (subcutaneous fatty tissue)
- Scarpa’s fascia (membranous layer of the anterior abdominal wall)
- External abdominal oblique fascia and muscle (lateral), and rectus abdominis muscle (medial)
- Rectus abdominis has:
- Anterior rectus fascia
- Rectus muscle
- Posterior rectus fascia:
- Ends midway between the umbilicus and pubic tubercle
- The lower edge is referred to as the arcuate line.
- Linea alba: fibrous band that runs midline between the 2 rectus muscles
- Internal abdominal oblique muscle
- Transversus abdominis muscle
- Transversalis fascia (underlies the transversalis muscle and posterior rectus fascia)
- Preperitoneal fat
Types of ventral hernias
- Hernias that occur along the linea alba, from the xiphoid process to the umbilicus
- Constitute 1.6%–3.6% of abdominal wall hernias
- 2–3 times more common in men
- Small defects that produce pain disproportionate to their size
- Hernias that occur through the umbilical ring of the linea alba
- Pediatric population:
- The umbilical ring is open at birth (to allow passage of umbilical vessels).
- Spontaneous closure generally occurs during the 1st 2 years of life and is closed in most children by 5 years of age.
- Surgical repair is indicated if umbilical hernias persist beyond the 5th year of life with no decrease in the size of the defect.
- Up to 8 times more common in children of African American descent
- Adult population:
- Most commonly acquired
- More common in women and in conditions that cause increased intra-abdominal pressure:
- Hernias that occur through the scar tissue of past surgical incisions due to poor wound healing and excessive tension
- Risk factors for incisional hernia:
- Chronic obstructive pulmonary disease
- Diabetes mellitus
- Chronic corticosteroid use
- Surgical site infection
- Hernias that occur through the transversus abdominis muscle aponeurosis (Spigelian aponeurosis):
- Bound by the lateral edge of the rectus muscle medially and linea semilunaris laterally
- Most common in the “Spigelian belt”: the transverse 6-cm zone around the arcuate line (lower edge of the posterior rectus sheath)
- The majority of these hernias are small (1–2 cm) and most present during the 4th to 7th decades of life.
- Difficult to identify on physical exam, often require imaging
- Potential complication after creation of a stoma
- Occurs with up to 50% of colostomies, less common with ileostomy
- Asymptomatic in most cases and routine repair is not recommended
- Obstruction or incarceration can occur in rare cases and require repair.
- Strangulated hernias or hernias with incarcerated intestines need to be repaired emergently due to the risk of bowel necrosis.
- Nonincarcerated hernias can be approached electively:
- Should be repaired if the hernia causes pain or discomfort
- Spigelian hernias should always be repaired due to the high risk of incarceration.
- Approximating the edges of the hernia defect with sutures
- Suturing, by definition, is not tension-free as it entails pulling together the edges of the defect.
- Thus, the rates of failure may be as high as 50%.
- Generally, only suitable for very small defects (< 1 cm)
- Other indications:
- A contaminated surgical field, where the risk of mesh infection is unacceptably high
- Hernias in children
- Involves placement of a prosthetic material to cover the hernia defect
- Prosthetic materials can be synthetic (different types of polymers) or biologic (derived from human or animal tissues).
- Synthetic meshes provide more durable repair and are preferred in the majority of cases.
- Biologic meshes are preferred sometimes in a contaminated field to avoid synthetic mesh infection although evidence for their advantage in this situation is lacking.
- Options for mesh placement:
- Between the bellies of the rectus abdominis muscle (inlay)
- Over the anterior aponeurosis of the rectal sheath (overlay)
- Intraperitoneally (underlay)
- Behind the rectus abdominis muscles (retro rectus)
- Between the rectus abdominis muscle and the peritoneum (preperitoneal)
- Between the internal oblique and transversus abdominis muscles that run behind the rectus abdominis muscle (intramuscular)
- Laparoscopic versus open approach:
- Most small- and medium-sized hernias can be repaired with either approach.
- The chosen method largely depends on the surgeon’s expertise.
- Very large hernias, especially those involving the loss of abdominal domain, are repaired in an open fashion. The repair process can be quite complex and is sometimes done in stages.
- Laparoscopy has the advantages of a shorter hospital stay and faster recovery.
- Mesh infection
- Surgical site infection
- Intestinal injury
- Mesh-enteric fistula
- Seroma: an accumulation of exudative secretions in potential spaces when the reabsorption capacity of the tissues is overwhelmed
Inguinal hernias occur through the floor or the internal ring of the inguinal canal.
- 75% of all hernias are inguinal.
- Men are 25 times more likely to have a groin hernia.
- The indirect variant is more common than the direct variant (2:1).
- Most commonly occur on the right side
- Strangulation occurs in 1%–3% of all inguinal hernias.
- The hernia sac passes through the internal inguinal ring toward the external inguinal ring and into the scrotum.
- Frequently congenital and associated with patent processus vaginalis
- The hernia sac protrudes anteriorly and is medial to the internal inguinal ring and inferior epigastric vessels.
- Hesselbach’s triangle (site of direct herniation): formed by the inguinal ligament, inferior epigastric vessels, and rectus sheath
- Mostly acquired secondary to muscular weakness and are more common in older men
- Combined (pantaloon): both indirect and direct hernia components
Anatomy of the inguinal canal
- An oblique passage in the inferior aspect of the abdominal wall of the inguinal regions
- Directed downward and medially
- 3.5–4 cm in length
- Allows passage of the spermatic cord in men and the round ligament in women
- 2 openings:
- Deep (internal) ring
- Superficial (external) ring
- Processus vaginalis:
- Peritoneal outpouching into the inguinal canal associated with the descent of testes during embryonic development
- Normally obliterated by birth
- Creates anatomical predisposition for herniation if not obliterated
|Boundary||Level of the deep ring||Middle||Level of the superficial ring|
|Anterior wall||Internal oblique External oblique||External oblique aponeurosis||External oblique aponeurosis (crura)|
|Posterior wall||Transversalis fascia||Transversalis fascia||Conjoint tendon|
|Roof||Transversalis fascia||Arching fibres of internal oblique and transversus abdominis||Medial crus of external oblique|
|Floor||Inguinal ligament||Inguinal ligament||Lacunar ligament|
- Incarceration or strangulation (emergent)
- Symptomatic hernia (associated with pain or discomfort)
- A transverse incision is made above the inguinal ligament, which is at the midpoint between the anterior superior iliac spine and the pubic tubercle.
- The external oblique aponeurosis is incised, with care taken to identify the genital branch of the genitofemoral nerve and the ilioinguinal nerve.
- The spermatic cord is mobilized and the hernia sac is dissected free.
- The contents of the hernia sac are reduced.
- The hernia sac can be reduced (direct), or the neck of the hernia sac can be ligated and excised (indirect).
- Primary repair (tissue repair) is rarely used nowadays as the failure rates are quite high.
- Options for tissue repair:
- Bassini: approximation of the transversus abdominis and the conjoint tendon (internal oblique aponeurosis) to the inguinal ligament
- Layered repair
- Running suture to approximate the transversus abdominis aponeurosis to the inguinal iliopubic tract
- Running suture to approximate the internal oblique to the inguinal ligament
- Interrupted, nonabsorbable suture to approximate the edge of the transversus abdominis aponeurosis to Cooper’s ligament
- Cooper’s ligament and the transversus abdominis are secured to the iliopubic tract.
- A relaxing incision is made in the anterior rectus sheath 1 cm above the pubic tubercle.
- Mesh repair:
- Lichtenstein repair:
- A synthetic mesh with a slit in the middle is inserted into the canal to accommodate the spermatic cord and wrap around it.
- Using nonabsorbable suture, the mesh is secured to the pubic tubercle superiorly along the transversus abdominis and inferiorly along the shelving edge of the inguinal ligament.
- Plug and patch:
- A cone-shaped piece of polypropylene mesh is inserted into the internal ring.
- A flat piece of mesh is used to reinforce the floor of the inguinal canal similar to the process used in Lichtenstein repair.
- Lichtenstein repair:
- Always involves mesh placement
- Requires technical expertise
- Totally extraperitoneal (TEP) technique:
- Abdominal cavity is not entered.
- Dissection is performed in the preperitoneal space with a balloon and insufflation.
- Limited working space
- Transabdominal preperitoneal (TAPP) technique:
- Abdomen is entered using the open Hassan technique or Veress needle.
- Peritoneum is taken down and mesh is placed in the preperitoneal space.
- Larger working space
- Chronic groin pain
- Testicular atrophy (damage to the testicular artery)
- Infertility (mesh fibrosis)
- Orchitis: acute inflammation of the testis due to viral or bacterial infections
- Scrotal hematoma
- Urinary retention
Femoral hernias are hernias that occur through the femoral triangle (below the inguinal ligament).
- Up to 10 times more common in women than men
- Occurs more commonly on the right side
- The highest rate of strangulation among all hernias (10%–20%)
- High likelihood of strangulation (40%); therefore, surgical intervention is always indicated
- The femoral ring is roughly 1 cm in diameter and bound by:
- Femoral vein laterally
- Iliopubic tract anteriorly
- Cooper’s ligament posteriorly
- The pubic tubercle forms the apex of the femoral canal triangle.
- The hernia will pass medial to the femoral vessels through the femoral canal.
- Open repair:
- McVay repair approximates the iliopubic tract to Cooper’s ligaments.
- Preferred approach if there is strangulated bowel, as there is no need for mesh placement
- The lacunar ligament should be divided if the incarcerated contents cannot be reduced.
- Laparoscopic repair:
- TEP laparoscopic approach
- TAPP laparoscopic approach
- Complications are similar to those seen in inguinal hernias.
- Malangoni, M.A., Rosen, M.J. (2012). In Mattox, K. L., et al. (Eds.), Sabiston Textbook of Surgery: The Biological Basis of Modern Surgical Practice. pp. 1114‒1140.
- Turnage, R.H., Badgwell, B. (2012). In Mattox, K. L., et al. (Eds.), Sabiston Textbook of Surgery: The Biological Basis of Modern Surgical Practice. pp. 1088‒1113.
- Brooke, D.C. (2020). Overview of abdominal wall hernias in adults. In Chen, W. (Ed.). UpToDate, Retrieved April 23, 2021, from https://www.uptodate.com/contents/overview-of-abdominal-wall-hernias-in-adults
- Ramsook, C. (2020). Inguinal hernia in children. UpToDate, Retrieved May 03, 2021, from https://www.uptodate.com/contents/inguinal-hernia-in-children
- Brooks, D.C., Hawn, M. (2019). Classification, clinical features, and diagnosis of inguinal and femoral hernias in adults. UpToDate, Retrieved May 03, 2021, from https://www.uptodate.com/contents/classification-clinical-features-and-diagnosis-of-inguinal-and-femoral-hernias-in-adults