Hernia

• Inguinal hernia


  A type of abdominal wall hernia that occurs in the groin area
• Inguinal herniorrhaphy is one of the most commonly performed operations in the United States
• In 2010 nearly 515,000 inguinal hernia operations were performed in hospitals, and an additional 450,000 were performed in ambulatory surgery centers
• Approximately 75% of abdominal wall hernias occur in the groin
• 90% of inguinal hernia repairs are performed in men, and 10% are performed in women
• The lifetime risk of inguinal hernia is 27% in men and 3% in women
• The incidence of inguinal hernia in men has a bimodal distribution, with peaks before the first year of age and after age 40
• Approximately 70% of femoral hernia repairs are performed in women
• Inguinal hernias are five times more common than femoral hernias
• Surgical repair of hernias has been documented as far back as in ancient Egyptian and Greek civilizations
• In the past, early management of inguinal hernias often involved a conservative approach with operative management reserved only for complications
• Surgery often involved routine excision of the testicle, and wounds were closed with cauterization or allowed to close by secondary intention
• These procedures were performed without aseptic technique, and infection and recurrence rates were high
• From the late 1700s to the early 1800s, physicians including Hesselbach, Cooper, Camper, Scarpa, Richter, and Gimbernat identified vital components of the inguinal region from cadaveric dissection
• This improved understanding of the anatomy and pathophysiology of inguinal hernias
• Bassini (1844–1924) pioneered a new method that transformed inguinal hernia repair into a successful venture with minimal morbidity
• The Bassini repair was then modified into the McVay and Shouldice repairs
• In the 1980s, Lichtenstein applied a piece of mesh to the floor of the inguinal canal, allowing for a truly tension-free repair
• The laparoscopic method for inguinal hernia repair has become more sophisticated with refinements in approach and technique
• Successful surgical treatment of inguinal hernias depends on a sound grasp of inguinal anatomy
• Inguinal canal


  An approximately 4- to 6-cm long cone-shaped region situated in the anterior portion of the pelvic basin
• Boundaries of the inguinal canal

  • External oblique aponeurosis anteriorly
  • Internal oblique muscle laterally
  • Transversalis fascia and transversus abdominis muscle posteriorly
  • Internal oblique and transversus abdominis muscle superiorly
  • Inguinal (Poupart's) ligament inferiorly

  
• Structures in the spermatic cord

  • 3 arteries
  • 3 veins
  • 2 nerves
  • Pampiniform venous plexus
  • Vas deferens
• Additional important structures surrounding the inguinal canal

  • Iliopubic tract
  • Lacunar ligament
  • Cooper's ligament
  • Conjoined tendon

  
• Iliopubic tract


  An aponeurotic band that begins at the anterior superior iliac spine and inserts into Cooper's ligament from above

  
• Lacunar ligament


  The triangular fanning of the inguinal ligament as it joins the pubic tubercle
• Cooper's ligament


  The lateral portion of the lacunar ligament that is fused to the periosteum of the pubic tubercle

  
• Conjoined tendon


  The fusion of the inferior fibers of the internal oblique and transversus abdominis aponeurosis at the point where they insert on the pubic tubercle

  
• Indirect inguinal hernia


  Protrudes lateral to the inferior epigastric vessels, through the deep inguinal ring

  
• Direct inguinal hernia


  Protrudes medial to the inferior epigastric vessels, within Hesselbach's triangle

  
• Femoral hernia


  Protrudes through the small and inflexible femoral ring, traversing the empty space between the femoral vein and the lymphatic channels
• Nyhus classification


  Categorizes hernia defects by location, size, and type
• Laparoscopic inguinal hernia repair requires knowledge of inguinal anatomy from a posterior perspective


  • Intraperitoneal points of reference: peritoneal folds, bladder, inferior epigastric vessels, psoas muscle
  • Potential spaces: Bogros's space, space of Retzius
  • Myopectineal orifice of Fruchaud

  
• Inferior epigastric vessels


  Derived from the external iliac artery, anastomose with the superior epigastric artery

  
• Nerves of interest in the inguinal region

  • Ilioinguinal nerve
  • Iliohypogastric nerve
  • Genitofemoral nerve
  • Lateral femoral cutaneous nerve

  
• Anatomical structures


  • Umbilicus
  • Median umbilical ligament (urachus)
  • Medial umbilical ligament (obliterated umbilical vein)
  • Lateral umbilical ligament (inferior epigastric vessels)
  • Lateral fossa (indirect hernia)
  • Medial fossa (direct hernia)
  • Supravesical fossa

  
• Figure 37-4. Posterior view of intraperitoneal folds and associated fossa

  
• Nyhus classification system


  • Type I: Indirect hernia; internal abdominal ring normal; typically in infants, children, small adults
  • Type II: Indirect hernia; internal ring enlarged without impingement on the floor of the inguinal canal; does not extend to the scrotum
  • Type IIIA: Direct hernia; size is not taken into account
  • Type IIIB: Indirect hernia that has enlarged enough to encroach upon the posterior inguinal wall; indirect sliding or scrotal hernias are usually placed in this category because they are commonly associated with extension to the direct space; also includes pantaloon hernias
  • Type IIIC: Femoral hernia
  • Type IV: Recurrent hernia; modifiers A–D are sometimes added, which correspond to indirect, direct, femoral, and mixed, respectively

  
• Ilioinguinal nerve


  • Arises from L1, pierces the transversus and internal oblique muscles to enter the inguinal canal and exits through the superficial inguinal ring, supplies somatic sensation to the skin of the upper and medial thigh, in males innervates the base of the penis and upper scrotum, in females innervates the mons pubis and labium majus

  
• Iliohypogastric nerve


  • Arises from T12–L1, pierces the deep abdominal wall, courses between the internal oblique and transversus abdominis, divides into lateral and anterior cutaneous branches