Hernias

38 Hernias



Chandra D. Aubin



image      Key Points




• Smaller defects in the abdominal wall are more likely to be manifested as incarcerated or strangulated hernias.


• Reduction of a hernia should not be attempted if strangulation is suspected.


• Hernias with signs or symptoms suggestive of bowel obstruction or ischemia are true surgical emergencies and require immediate consultation for operative repair.


• Manual reduction can be aided by placement of the patient in a supine or Trendelenburg position, application of ice to the hernia site before reduction, and administration of analgesics or anxiolytics, or both.


• Postoperative complications of herniorrhaphy include wound infection, seroma, hematoma, ileus, small bowel obstruction, recurrence of the hernia, erosion of preperitoneal mesh into intraabdominal organs, fistula formation, genitourinary trauma, and chronic pain secondary to nerve injury.



Epidemiology


Herniorrhaphy (also known as hernioplasty, or surgical repair of a hernia) is a common procedure in the United States. Approximately 800,000 inguinal hernia repairs were performed in the United States in 2003; mesh was used in 90% of the cases.1


Of groin hernias, inguinal hernias (96%) are much more common than femoral hernias (4%). The male-to-female ratio for inguinal hernias is 9 : 1, and that for femoral hernias is 1 : 4. In elderly women, femoral hernias are as common as inguinal hernias. The incidence of strangulation increases with advancing age.


Operative mortality for a strangulated hernia is 5% to 10% in patients older than 80 years, as compared with 3% for elective repair in that age group. Mortality increases to 19% when bowel necrosis is present.


The incidence of postoperative intraabdominal hernias is increasing because of the higher number of Roux-en-Y gastric bypass procedures performed each year; postoperative hernias are observed in 2.5% to 4.5% of patients undergoing bariatric surgery.


Incisional hernias of the abdominal wall occur in up to 11% of all other postoperative patients and in as many as 23% of patients with postoperative wound infections. Trocar site hernias after laparoscopic surgery are reported in up to 6% of patients. Parastomal hernia formation occurs in 28% of ileostomies and 48% of colostomies. Morbidity depends on the location and contents of the hernia, as well as the development of incarceration or strangulation.



Pathophysiology


Hernias are congenital or acquired defects in the abdominal wall that allow protrusion of intraabdominal contents through the pathologic opening. The characteristic finding consists of pain and swelling at the hernia site. Intraabdominal hernias, which can occur spontaneously or after surgery or trauma, are caused by defects in the diaphragm, mesentery, or ligamentous structures.


Incarcerated hernias are those in which abdominal contents have become trapped in the opening (i.e., nonreducible). Bowel incarceration can be manifested as pain, vomiting, or frank obstruction.


Strangulated hernias involve a compromise of the blood supply to the hernia contents. Strangulation can be manifested as fever, ischemia, or necrosis of the hernia contents and, occasionally, erythema or necrosis of the skin overlying the hernia. Smaller defects in the abdominal wall are more likely to be manifested as incarceration or strangulation.


Reduction—replacement of the hernia contents back into the abdominal cavity—is the immediate treatment of a hernia. Reduction of a hernia is accomplished by gentle pressure over the area of herniation. Reduction is assisted by use of the supine or Trendelenburg position, application of ice, analgesia, and procedural sedation to relax the musculature of the abdominal wall. Reduction should not be attempted if necrosis of the hernia contents is suspected. Definitive hernia treatment is surgical repair.



Nomenclature


Table 38.1 and Box 38.1 summarize the nomenclature of hernias, and Figures 38.1 to 38.13 illustrate some of the hernia types.


Table 38.1 Nomenclature of Hernias
























































































































Groin Hernias
Inguinal hernia (Fig. 38.1) Physical examination cannot accurately distinguish between indirect and direct inguinal hernias
 Indirect Occurs through the inguinal canal
Inguinal canal contents include the ilioinguinal nerve, genital branch of the genitofemoral nerve, spermatic cord in men (vas deferens, testicular artery, and vein), and round ligament in women
 Direct 65% of inguinal hernias are indirect
Weakness of the aponeurosis of the transversus abdominis and transversalis fascia in the Hesselbach triangle (the medial border of which is the lateral aspect of the rectus abdominis, the superior border is the epigastric artery, and the inferior border is the inguinal ligament)
Femoral hernia Occurs through the femoral canal, inferior to the inguinal ligament, medial to the femoral vein
More common in elderly, parous women
Sportsman’s hernia Syndrome of persistent groin pain in athletes; probably caused by recurrent or persistent groin strain, osteitis pubis, or a nonpalpable hernia
More common in kicking sports
Abdominal Wall Hernias
Anterior (Fig. 38.2)  
 Epigastric hernia Occurs through the linea alba, the midline between the xiphoid line and umbilicus
 Umbilical hernia Caused by an abnormally large or weak umbilical ring
Umbilical hernia usually closes spontaneously in infancy but does not heal in adulthood
Rarely incarcerates in children
Worsened by pregnancy, obesity, or cirrhosis with ascites
 Spigelian hernia (Figs. 38.3 and 38.4) Lateral ventral hernia through the spigelian zone: transversalis fascia between the lateral margin of the rectus abdominis muscle, medial margins of the external and internal obliques, and the transversus abdominis muscles
Accounts for 1-2% of all hernias
 Ventral or incisional hernia (Fig. 38.5) Trocar sites:


Difficult to recognize on physical examination


Dangerous cause of early postoperative small bowel obstruction


Can be the Richter type (incarceration of one intestinal wall)


Iliac crest bone graft sites


Parastomal hernias

 Traumatic Caused by blunt or penetrating trauma
“Handlebar” hernia:


Can occur in any location on the abdominal wall from a fall on a bicycle handlebar with tear of the abdominal wall muscles


Has also been reported in the thorax from a tear of the intercostal muscles (similar hernias have been reported as a result of severe coughing)

 Congenital abdominal wall defects Surgical emergencies in neonates:


Immediate management: cover the abdominal contents with warm moist saline-soaked gauze, insert a nasogastric tube, administer intravenous fluids and antibiotics, obtain surgical consultation


Types:


Gastroschisis: intact umbilical cord, evisceration of the bowel through a defect usually to the right of the cord; no membrane covering


Omphalocele: herniation of the bowel, liver, and other organs into the intact umbilical cord; membrane present unless ruptured

Posterior (lumbar) hernias (Fig. 38.6) Bounded superiorly by the 12th rib, inferiorly by the iliac crest, posteriorly by the erector spinae muscles, and anteriorly by the posterior border of the external oblique muscle
Types:


Inferior or Petit: just superior to iliac crest (point up)


Superior or Grynfeltt: just below the 12th rib, inverted triangle (point down)

Diaphragmatic Hernias
Congenital hernia (Fig. 38.7) Eventration: thin diaphragm with normal but widely spaced muscle fibers
Posterolateral: through the foramen of Bochdalek
Anterior, retrosternal, or parasternal: through the foramen of Morgagni (Figs. 38.8 and 38.9)
Peritoneopericardial
Acquired hernia Hiatal: sliding or fixed
Paraesophageal
Acquired eventration: caused by phrenic nerve injury and paralysis
Traumatic (Fig. 38.10)
Pelvic Wall and Floor Hernias
Sciatic hernia (Fig. 38.11) Protrusion of the peritoneal sac and contents through the greater or lesser sciatic foramen
Obturator hernia (Fig. 38.12) Protrusion of preperitoneal fat or intestine through the obturator foramen
Perineal hernia Protrusion of a viscus through the pelvic floor (rare)
Prolapse Weakness of the pelvic floor muscles can cause a cystocele, rectocele, and uterine or rectal prolapse
Intraabdominal Hernias
Spontaneous  
 Transmesenteric hernia Through the sigmoid mesocolon, broad ligament, or falciform ligament
 Transomental hernia Hernia beneath a mesenteric or peritoneal fold (no disruption of the peritoneum)
Locations:


Epiploic foramen of Winslow (Fig. 38.13)


Paraduodenal


Superior ileocecal fossa


Internal supravesicular

Postoperative Transmesenteric and transomental hernias are most common, especially after Roux-en-Y procedures
May occur through the falciform ligament from a trocar puncture during laparoscopic cholecystectomy
Retroanastomotic—may occur behind the anastomosis


Box 38.1 Eponyms Associated with Hernias




Richter hernia (partial enterocele): Herniation of only the anterior surface of the intestinal wall through the hernia defect; accounts for 10% of strangulated hernias


Amyand hernia: Acute appendicitis in the sac of an inguinal hernia


Garengeot hernia: Acute appendicitis in the sac of a femoral hernia


Littre hernia: Strangulated Meckel diverticulum in a hernia sac


Maydl hernia: Internal hernia with double-loop strangulation


Chilaiditi syndrome: Symptomatic interposition of the intraabdominal contents between the liver and diaphragm; can become incarcerated

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Jun 14, 2016 | Posted by in EMERGENCY MEDICINE | Comments Off on Hernias

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