Gastrointestinal and Abdominal: Hernias

Question 1

Hernias

Answer 1

A hernia occurs when a defect or weakness in a mus-

cular or fascial layer allows tissue to exit a space in

which it is normally contained. Hernias are categorized

as reducible, incarcerated, or strangulated. Reducible

hernias can be returned to their body cavity of origin.

Incarcerated hernias cannot be returned to their body

cavity of origin. Strangulated hernias contain tissue

with a compromised vascular supply. These are partic-

ularly dangerous because they lead to tissue necrosis.

If the bowel is involved, this can progress to perfora-

tion, sepsis, and death.

Question 2

Hernia: Epidemiology

Answer 2

Between 500,000 and 1,000,000 hernia repairs are per-

formed each year. Five percent of people have an

inguinal hernia repair during their lifetime. Half of all

hernias are indirect inguinal, and one fourth are direct

inguinal. In decreasing incidence are incisional and ven-

tral (10%), femoral (6%), and umbilical hernias (3%).

Obturator hernias are rare. Indirect inguinal hernias are

the most common in both males and females; overall,

hernias have a five:one male predominance. Femoral

hernias are more common in females than in males.

Question 3

Inguinal Hernias: Anatomy

Answer 3

The abdominal contents are kept intraperitoneal by

fascial and muscular layers: the innermost layer is the

transversalis fascia, with the three more superficial

musculofascial layers being the transversus abdo-

minis, the internal oblique, and the external oblique

(see Color Plate 8).

During normal development, the testes begin in an

intra-abdominal position and descend through the inter-

nal ring, taking with them a layer of peritoneum that is

stretched into a hollow tube called the processus vagi-

nalis. This invagination of peritoneum, exiting through

the deep and superficial inguinal rings and extending

into the scrotum to where the testicle has terminated its

descent, will result in an indirect inguinal hernia unless

the following occurs: the tubular processus vaginalis

must collapse upon itself, fusing opposing peritoneal

surfaces and obliterating the tube into a cord-like struc-

ture. If this obliteration/fusion of the peritoneal layers

does not occur completely, an indirect inguinal hernia

will result (Fig. 11-1A).

A direct inguinal hernia results from a weakness in

the abdominal wall (specifically, the transversalis) in

the area just deep to the superficial ring where the

spermatic cord exits the inguinal canal before traveling

down into the scrotum (Fig. 11-1B). This area is medial

to the epigastric vessels and is called Hesselbach trian-

gle (defined as the edge of the rectus sheath medially,

the inguinal ligament inferiorly, and the inferior epi-

gastric vessels laterally; Fig. 11-2).

Progressive structural weakening and loss of

integrity of the transversalis at this location allows

bulging of the weakened abdominal wall through the

area of Hesselbach triangle, the most medial aspect and

back wall of the inguinal canal itself. Once the defect

is large enough, bowel or other abdominal contents

can protrude directly through the fascia and out the

superficial ring. Direct inguinal hernias are typically

seen in older individuals, whereas indirect inguinal her-

nias predominate in the pediatric population. Also, the

external oblique, which inserts onto the pubic tubercle

and bounds the external superficial ring, has no func-

tion in the pathogenesis of hernias.

Question 4

Inguinal Hernia: History

Answer 4

Patients with reducible inguinal hernias describe an

intermittent bulge in the groin or scrotum. Persistence

of the bulge with nausea or vomiting raises concern for

incarceration. Severe pain at the hernia site with nausea

or vomiting may occur with strangulation

Question 5

Inguinal Hernia: Physical Examination

Answer 5

With the patient in a standing position, a fingertip

is directed upward to find the superficial ring. This

is facilitated in male patients by entering the loose

scrotum at its base and following the course of the

spermatic cord until the superficial ring is encoun-

tered. With the fingertip inserted into the ring, a

bulge is felt in small hernias as the patient coughs or

bears down (Fig. 11-3).

In larger hernias, the herniated sac can be palpated

without the aid of Valsalva maneuvers. With the

patient in the supine position, reducible hernias can be

reduced into the abdomen, whereas incarcerated her-

nias cannot. Strangulated hernias are tender as a result

of peritoneal inflammation. Abdominal distention is

often encountered as a result of bowel obstruction.

Question 6

Inguinal Hernia: Treatment

Answer 6

Traditionally, the simple presence of an inguinal hernia

was indication enough for a surgeon to advise elective

repair. Conventional thinking was that the benefit of

preventing a hernia accident (i.e., acute incarceration

with bowel obstruction or strangulation of abdominal

contents) clearly outweighed the potential risks and

complications of elective hernia repair. However, the

natural history of untreated inguinal hernias and the

risks they posed had never been precisely determined

until recently. In 2006, a landmark clinical trial involving

720 men with minimally symptomatic inguinal hernias

randomly assigned patients to either watchful waiting or

surgery with standard open tension-free repair. The key

study finding was that the rate of hernia accidents are

extremely rare (1.8 per 1,000 patient-years), leading

to the study’s conclusion that, “A strategy of watchful

waiting is a safe and acceptable option for men with

asymptomatic or minimally symptomatic inguinal

hernias. Acute hernia incarcerations occur rarely, and

patients who develop symptoms have no greater risk of

operative complications than those undergoing prophy-

lactic hernia repair.”

Modern hernioplasty is based on the idea of tension-

free repair using an implantable biocompatible prosthe-

sis to reconstruct the fascial hernia defect (Figs. 11-4 and

11-5). The superiority of the concept of mesh tension-

free repair versus traditional nonmesh tension-producing

repair was validated by a Cochrane Group review pub-

lished in 2002. The use of mesh was found to signifi-

cantly reduce the risk of hernia recurrence by an

astounding 50% to 75%. Reducible inguinal hernias can

be repaired on an elective basis depending on the degree

of patient symptoms. Both open and laparoscopic tech-

niques are acceptable, although a recent Veterans Affairs

study (2004) showed a higher recurrence rate with

laparoscopic repair (10%) when compared with open

repair (4%) of primary hernias. The usual indications for

laparoscopic repair are bilaterality and recurrence.

Interestingly, the Veterans Affairs study showed the rates

of recurrence after repair of recurrent hernias as being

similar with laparoscopic versus open repairs (10.0%

versus 14.1%). Inguinal hernias in adult men should

typically be repaired with mesh to avoid recurrence. In

women, the round ligament is ligated and the ring closed

so mesh use is variable.

When a hernia is not reducible with gentle pres-

sure, a trial of Trendelenburg position, sedation, and

more forceful pressure can be attempted. If the her-

nia is thought to be strangulated, then reduction is

contraindicated, because reducing necrotic bowel

into the abdomen may produce bowel perforation

and subsequent lethal sepsis. Emergency surgery is

indicated in this situation. A sample operative note

for an inguinal hernia is provided in the Appendix.

Question 7

Umbilical Hernias

Answer 7

Umbilical hernias occur at the umbilicus and are con-

genital. They result from incomplete closure of the

fetal umbilical defect. Most resolve spontaneously by

the age of 4 years.

Question 8

Umbilical Hernias: Epidemiology

Answer 8

The incidence is 10% of Caucasians and 40% to 90%

of African Americans.

Question 9

Umbilical Hernias: History

Answer 9

The patient may have a bulge at the umbilicus.

Question 10

Umbilical Hernias: Treatment

Answer 10

Indications for operation include incarceration, stran-

gulation, or cosmetic concerns

Question 11

Femoral Hernias

Answer 11

Femoral hernias occur through the femoral canal,

located below the inguinal ligament and defined by

the femoral vein laterally, the inguinal ligament supe-

riorly, the lacunar ligament medially, and Cooper lig-

ament inferiorly.

Question 12

Incisional Hernias

Answer 12

occur through a previous surgical incision

Question 13

Ventral Hernias

Answer 13

occur in the midline along the linea alba, usually between the xiphoid and umbilicus. The herniation is through a weakness of

the decussating fibers of the linea alba.

Question 14

Spigelian Hernias

Answer 14

are found at or below the junction between the

vertically oriented semilunar line lateral to the rectus

abdominus muscle and the transversely oriented

arcuate line (linea semicircularis)

Question 15

Pantaloon hernia

Answer 15

is a combined direct and indirect inguinal hernia

where both hernias straddle each side of the inferior

epigastric vessels and protrude like pant legs (pan-

taloon)

Question 16

Richter hernia

Answer 16

occurs when a knuckle of bowel protrudes into a hernia defect, but only a portion of the circumference is involved and the bowel

lumen remains patent. Typically, the result is gan-

grenous necrosis of the herniated tissue.

Question 17

Sliding Hernia

Answer 17

is any hernia that contains intra-abdominal organs

Question 18

Internal Hernias

Answer 18

may occur in patients after

abdominal operations when bowel gets trapped as a

result of new anatomic relationships

Question 19

Obturator hernias

Answer 19

are typically found in thin, older adult women

who present with bowel obstruction caused by small

bowel herniation into the obturator canal. Obturator

nerve compression by the hernia can result in pares-

thesias or pain radiating down the medial thigh (the

Howship-Romberg sign).

Question 20

Littre hernia

Answer 20

is any groin hernia that contains a Meckel’s diverticulum

Question 21

NOT A HERNIA, but mistaken as one: Diastasis Recti

Answer 21

Something that is not a hernia but is often con-

fused as one is diastasis recti. An upper midline bulge

develops when the patient performs a Valsalva

maneuver, and herniation is suspected. On close

physical examination, however, no actual defect or

“hole” in the fascia is found. Rather, the linea alba has

become attenuated and weak, resulting in widening

of the distance between the rectus muscles. It is this

thin, stretched linea alba that bulges out and mimics

a large hernia. Surgical repair is not indicated.

Question 22

Key Points: Hernia

Answer 22

Hernias are extremely common. Inguinal hernias are

the most common, and 5% of people require repair

during their lifetime.

•

Indirect inguinal hernias arising from a patent

processus vaginalis are more common than direct

hernias from abdominal wall weakness.

•

Hernias that become incarcerated should be oper-

ated on urgently.

•

Hernias that become strangulated are a surgical

emergency.

•

Umbilical hernias are congenital, more common in

African Americans, and frequently resolve sponta-

neously.

•

Diastasis recti is not a true herniation and does not

require surgical repair.

•

Modern hernioplasty is based on the principle of

tension-free repair using an implantable biocompati-

ble prosthesis to reconstruct the fascial hernia defect.