[Figure] "Hernia: Abdominal and Pelvic Landmarks"
A. Definition and Etiology

1. Abnormal protrusion of tissue through a normal or abnormal opening
2. Most hernias occur because of increased abdominal pressure
   1. Chronic cough, constipation (fecal impaction)
   2. Bladder outlet obstruction, Pregnancy, Heavy lifting
   3. Ascites

B. Types
[Figure] "Hernia: Abdominal Landmarks"

1. Inguinal [1]
   1. Begins anteromedial and superior to the inguinal ligament
   2. Lifetime risk 27% for men and 3% for women
   3. 500,000 inguinal hernia repairs annually in USA; 100,000 annually in UK
   4. Main indications for surgical repair are young age and risk of intestinal strangulation
   5. Trusses can be used to support some inguinal hernias
   6. Strangulation risk overall ~4.5% at 2 years
2. Direct Inguinal
   1. Herniation of abdominal contents directly through Hesselbach's triangle
   2. Due to weakness in the transversalis fascia
   3. Hesselbach's triangle is bordered by:
   4. Inguinal ligament
      1. Inferior epigastric vessels
      2. Lateral border of the rectus muscle (conjoined tendon).
   5. The hernia begins medial to the inferior epigastric vessels
3. Indirect Inguinal Hernia
   1. Herniation of abdominal contents through the internal ring
   2. More likely than direct to incarcerate / strangulate
   3. This is the most common type of hernia in men and women
   4. Occurs because the processes vaginalis fails to obliterate
   5. Begins lateral to the inf. epigastric vessels.
4. Femoral Hernia
   [Figure] "Hernia: Pelvic and Femoral Landmarks"
   1. Most often occur in thin, elderly women
   2. Herniation of abdominal material through femoral sheath
   3. The sheath (canal) contains (lateral to medial):
   4. Nerve, Artery, Vein, Extra space, Lymphatics (giving the mnemonic "NAVEL")
   5. Note that herniation occurs just medial to the vein, in the "extra" space
   6. This type of hernia is often strangulated by the Lacunar ligament
   7. Strangulation risk 22% at 3 months, 45% at 21 months [1]
5. Hiatal Hernia - Sliding Type [2]
   1. Actually this is a developmental abnormality
   2. GE junction slides up through diaphragm into thorax
   3. Often accompanied by gastroesophageal reflux disease, cough, early satiety
6. Paraesophageal Hiatal Hernia [2]
   1. Gastroesophageal junction is fixed, normally retroperitoneal
   2. Distal stomach and duodenum curve back laterally, through esophageal hiatus
   3. Surgery is generally indicated
7. Sliding Hernia
   1. The wall of viscus or its mesentery forms wall of hernia sac
   2. Usually seen with sigmoid colon.
8. Pantaloon: direct and indirect component of a hernia
9. Treitz: retroperitoneal hernia
10. Lumbar
    1. Protrusion between last rib and iliac crest
    2. Occurs where aponeurosis of transversus muscle is covered only by the latissimus dorsi
11. Richter's Hernia
    1. Parietal hernia
    2. Partial enterocele; a portion of the wall of the intestine is engaged in the hernia sac
    3. Up to 10% of hernias may include a Richter component
    4. Obstruction does not occur with these types of hernias
    5. However, strangulation and perforation may occur so these hernias must be repaired
12. Spigelian Hernia
    1. Lateral ventral hernia; abdominal hernia through the semilunar line
    2. Spigelius' line: slight groove in external abdominal wall
    3. It is parallel to the lateral edge of the rectus sheath
13. Incisional Hernia [1]
    1. Hernia following closure of abdominal incision
    2. Arises out of laparoscopic or open operation
    3. Asymptomatic in 60% of cases
    4. Physical exam with patient relaxed and supine usually reveals hernia
    5. Giant incisional hernia may be comproised by obesity, adhesion, abdominal cavity contraction

C. Differential Diagnosis

1. Hernia
2. Lymph Node
3. Saphena varix
4. Lipoma
5. Femoral Aneurysm
6. Psoas Abscess
7. Ectopic Testes
8. Hydrocele

D. Repair of Hernia [1,3]

1. High ligation of sac is key to repair in infants and children (Marcy Repair)
2. Bassini Repair
   1. Indirect hernia repair, most widely used
   2. Approximates transversalis fascia to Inguinal (Poupart's) ligament.
3. Halsted: direct hernia repair
4. McVay
   1. Direct, indirect and femoral reparis
   2. Requires relaxing incision to relieve tension.
5. Shouldice
   1. Direct and indirect repairs; very strong
   2. Transversalis fascia divided and attached to inguinal ligament
   3. Then conjoined tendon and internal oblique muscle are approximated to inguinal ligament
   4. Probably has the lowest recurrence rate
6. Laparoscopic Repair of Inguinal Hernia [1,4]
   1. Extraperitoneal laparaoscopic repair compared with conventional open surgery
   2. Laparoscopic repairs had more rapid recovery, fewer surgical wound infections, reduced recurrence [4]
   3. Laparoscopic repair had reduced recovery time and requirements for postoperative anesthesia compared with Shouldice repair [5]
   4. Open surgery superior to laparoscopic for mesh repair of primary inguinal hernia [7]
7. Mesh repair is superior to suture for treatment of incisional hernia [6]
8. Antibiotic impregnated mesh being investigated

References

1. Kingsnorth A and LeBlanc K. 2003. Lancet. 362(9395):1561
2. Sloan S, Rademaker AW, Kahrilas PJ. 1992. Ann Intern Med. 117(12):977
3. Schumpelick V, Treutner KH, Arlt G. 1994. Lancet. 344:375
4. Liem MSL, van der Graaf Y, van Steensel CJ, et al. 1997. NEJM. 336(22):1541
5. Juul P and Christensen K. 1999. Br J Surg. 86:316
6. Luijendijk RW, hop WCJ, van den Tol MP, et al. 2000. NEJM. 343(6):392
7. Neumayer L, Giobbie-Hurder A, Jonasson O, et al. 2004. NEJM. 350(18):1819