The presence of a PPV likely predisposes the patient to the
development of an inguinal hernia. This likelihood depends on the presence of
other risk factors such as inherent tissue weakness, family history, and
strenuous activity. Overall, there is limited data pertaining to the etiology of
inguinal hernia development. Several studies have documented strenuous physical
activity as a predisposing risk factor to acquiring an inguinal
hernia.11,12 Repeated physical exertion may increase intra-abdominal
pressure; however, whether this process occurs in combination with a PPV or
through age-related weakness of abdominal wall musculature is unknown. A
case-controlled study of over 1400 male patients with inguinal hernia revealed
that a positive family history was eight times as likely to lead to development
of a primary inguinal hernia. Chronic obstructive pulmonary disease
significantly increased the risk of direct inguinal hernias.13
Interestingly, several studies have noted a protective effect of obesity. In a
large, population-based prospective study of American individuals (First
National Health and Nutrition Examination Survey), the risk of inguinal hernia
development in obese men was only 50% that of normal weight males, while the
risk in overweight males was 80% that of nonobese men. A possible explanation is
the increased difficulty in detecting inguinal hernias in obese
individuals.14
One of the most intriguing areas under study is the role of
tissue biology in hernia formation. Epidemiologic studies have identified risk
factors that may predispose to a hernia, but there are limited data specifically
related to the molecular basis of these hernias. Early experiments involving
iatrogenic laythirsm resulted in hernia formation. Furthermore, microscopic
examination of skin of inguinal hernia patients demonstrated significantly
decreased ratios of type I to type III collagen. Type III collagen does not
contribute to wound tensile strength as significantly as type I collagen.
Additional analyses of similar skin revealed disaggregated collagen tracts with
decreased collagen fiber density.15 Collagen disorders such as
Ehlers-Danlos syndrome also are associated with an increased incidence of hernia
formation (Table 37-3). Tissue analysis has revealed that there is a
relationship between the aneurysmal component and hernias, owing to a pathologic
extracellular matrix metabolism.16 Although a significant amount of
work remains to elicit the biologic nature of hernias, studies such as these
provide compelling evidence for the presence of a genetic collagen defect.
Table 37-3 Connective Tissue Disorders Associated with Groin
Herniation
|
|
| Osteogenesis
imperfecta |
| Cutis laxa (congenital
elastolysis) |
| Ehlers-Danlos
syndrome |
| Hurler-Hunter
syndrome |
| Marfan syndrome |
| Congenital hip
dislocation in children |
| Polycystic kidney
disease |
| Alpha1-antitrypsin
deficiency |
| Williams
syndrome |
| Androgen insensitivity
syndrome |
| Robinow's
syndrome |
| Serpentine fibula
syndrome |
| Alport's
syndrome |
| Tel Hashomer
camptodactyly syndrome |
| Leriche's
syndrome |
| Testicular feminization
syndrome |
| Rokitansky-Mayer-Küster
syndrome |
| Goldenhar's
syndrome |
| Morris syndrome |
| Gerhardt's
syndrome |
| Menkes'
syndrome |
| Kawasaki
disease |
| Pfannenstiel
syndrome |
| Beckwith-Wiedemann
syndrome |
| Rubinstein-Taybi
syndrome |
| Alopecia-photophobia
syndrome |
|
Anatomy
It cannot be overstated that proficient knowledge of
inguinal anatomy is necessary to produce a lasting surgical cure of the inguinal
hernia. The groin region is a complex network of muscles, ligaments, and fascia
that are interwoven in a multiplanar fashion. To understand the anatomy of the
groin, it is best to first consider its components and then conceptualize them
according to operative approach. Because the vast majority of inguinal hernias
occur in men, general descriptions of groin anatomy contained herein will
pertain to males. The inguinal canal is approximately 4 to 6 cm long and is
situated in the anteroinferior portion of the pelvic basin (Fig. 37-2). Shaped
like a cone, its base is at the superolateral margin of the basin, with its apex
pointed inferomedially toward the symphysis pubis. The canal begins
intra-abdominally on the deep aspect of the abdominal wall, where the spermatic
cord passes through a hiatus in the transversalis fascia (in females, this is
the round ligament). This hiatus is termed the deep or internal inguinal
ring. The canal then concludes on the superficial aspect of the abdominal
wall musculature at the superficial or external inguinal ring, the point at
which the spermatic cord crosses the medial defect of the external oblique
aponeurosis. In the normal situation, parietal peritoneum covers the
intra-abdominal portion of the spermatic cord, as well as the internal ring.
Anteriorly, the boundary of the canal is comprised of the external oblique
aponeurosis and internal oblique muscle laterally. Posteriorly, the floor of the
inguinal canal is formed by the fusion of the transversalis fascia and
transversus abdominus muscle, although up to one fourth of subjects are found to
have only the transversalis fascia forming the posterior floor. The superior
boundary is an arch formed by the fibers of the internal oblique muscle. Lastly,
the inferior margin consists of the inguinal ligament. The spermatic cord
consists of three arteries, three veins, and two nerves. As well, it contains
the pampiniform venous plexus anteriorly and the vas deferens posteriorly, with
connective tissue and remnant of the processus vaginalis between. The cord is
then enveloped in layers of spermatic fascia.
Additional structures that are important to the
conceptualization of the inguinal canal include the inguinal ligament, Cooper's
ligament, iliopubic tract, lacunar ligament, and conjoined area (Fig. 37-3). The
inguinal ligament is also known as Poupart's ligament and is comprised of
the inferior fibers of the external oblique aponeurosis. The ligament stretches
from the anterior superior iliac spine to the pubic tubercle. The ligament
serves an important purpose as a readily identifiable boundary of the inguinal
canal, as well as a sturdy structure used in various hernia repairs. Cooper's
ligament is otherwise known as the pectineal ligament, although
controversy exists as to whether it is, in fact, a ligament at all. Its anatomic
site predisposes the structure to varied explanations of its nature and
relationships to contiguous structures. For all intents and purposes, it can be
considered as the lateral portion of the lacunar ligament that is fused to the
periosteum of the pubic tubercle. It also may include fibers from the
transversus abdominus, iliopubic tract, internal oblique, and rectus abdominus.
The iliopubic tract is an aponeurotic band that begins at the anterior superior
iliac spine and inserts into Cooper's ligament from above. It often is confused
with the inguinal ligament secondary to common origin and insertion points.
However, the iliopubic tract forms on the deep side of the inferior margin of
the transversus abdominus and transversalis fascia. The inguinal ligament is on
the superficial side of the musculoaponeurotic layer of these structures. The
shelving edge of the inguinal ligament is a structure that more or less connects
the iliopubic tract to the inguinal ligament. The iliopubic tract helps form the
inferior margin of the internal inguinal ring as it courses medially, where it
continues as the anterior and medial border of the femoral canal. The lacunar
ligament, or ligament of Gimbernat, is the triangular fanning out of the
inguinal ligament as it joins the pubic tubercle. Controversy exists as to
whether the lateral edge of the lacunar ligament forms the medial border of the
femoral canal. Controversy also exists as to the nature of the conjoined tendon.
It is commonly described as the fusion of the inferior fibers of the internal
oblique and transversus abdominus aponeurosis, at the point where they insert on
the pubic tubercle. This exact anatomic entity is hard to describe consistently.
More likely, the conjoined area is a combination of the transversus abdominus
aponeurosis, transversalis fascia, lateral edge of the rectus sheath, and
internal oblique muscle or its fibers.
Nerves of interest in the inguinal region are the
ilioinguinal, iliohypogastric, genitofemoral, and lateral femoral cutaneous
nerve (Figs. 37-4 and 37-5). The ilioinguinal and iliohypogastric nerve arise
together from the first lumbar nerve (L1). The ilioinguinal nerve emerges from
the lateral border of the psoas major and passes obliquely across the quadratus
lumborum. At a point just medial to the anterior superior iliac spine, it
crosses the internal oblique muscle to enter the inguinal canal between the
internal and external oblique muscles and exits through the superficial inguinal
ring. The nerve supplies the skin of the upper and medial thigh. In males, it
also supplies the penis and upper scrotum, while supplying the mons pubis and
labium majus in females. The iliohypogastric nerve arises from T12–L1 and
follows the ilioinguinal nerve. After the iliohypogastric nerve pierces the deep
abdominal wall in its downward course, it courses between the internal oblique
and transversus abdominis, supplying both. It then branches into a lateral
cutaneous branch and an anterior cutaneous branch, which pierces the internal
oblique and then external oblique aponeurosis above the superficial inguinal
ring. A common variant is for the iliohypogastric and ilioinguinal nerves to
exit around the superficial inguinal ring as a single entity. The genitofemoral
nerve arises from L1–L2, courses along the retroperitoneum, and emerges on the
anterior aspect of the psoas. It then divides into the genital and femoral
branches. The genital branch remains ventral to the iliac vessels and iliopubic
tract as it enters the inguinal canal just lateral to the inferior epigastric
vessels. In males, it travels through the superficial inguinal ring and supplies
the scrotum and cremaster muscle. In females, it supplies the mons pubis and
labia majora. The femoral branch courses along the femoral sheath, supplying the
skin anterior to the upper part of the femoral triangle. The lateral femoral
cutaneous nerve arises from L2–L3, but emerges from the lateral border of the
psoas muscle at the level of L4. It crosses the iliacus muscle obliquely toward
the anterior superior iliac spine. It then passes inferior to the inguinal
ligament where it divides to supply the lateral aspect of the thigh (Fig. 37-6).
Anterior Perspective
The aforementioned borders of the inguinal canal can be
readily appreciated when approaching an inguinal hernia in an open, anterior
fashion. Once the subcutaneous tissue is passed, the oblique fibers of the
external oblique aponeurosis are encountered. The external oblique muscle
originates on the lower eight ribs (Fig. 37-7). The course of the fibers runs
inferiorly from lateral to medial and is commonly referred to as hands in the
pockets as they are parallel to one's fingers in this orientation. As the
fibers approach the inguinal canal, they are no longer comprised of muscle, only
tendinous aponeurosis. Once the aponeurosis is exposed, the superficial inguinal
ring and inguinal ligament may be identified. The superficial ring consists of
two crura. The medial crus is formed by the fibers of the external oblique
aponeurosis and join with the lateral border of the rectus sheath. The inferior
crus is formed by the inguinal ligament, which inserts into the pubic bone. The
iliohypogastric nerve generally pierces the external oblique aponeurosis above
the superficial inguinal ring. The spermatic cord, genitofemoral and
ilioinguinal nerves are seen passing through the superficial inguinal ring. One
layer deep to the external oblique aponeurosis, these same structures are
visualized, as well as the deep inguinal ring. The inferior border of the
internal inguinal ring is formed by the iliopubic tract, while the rest of the
ring is formed by fibers of the transversalis fascia. Structures that are seen
entering the internal inguinal ring include the spermatic cord and genital
branch of the genitofemoral nerve.
The cord structures are enveloped by three fascial layers.
The internal fascial layer is derived from the internal oblique muscle and
contains the cremaster muscle. The external layer is adhered to the fascia of
the external oblique muscle and must be dissected to mobilize the cord. The
superficial fascia is also known as the fascia of Gallaudet or
innominate fascia. Superior to the cord, the arch of the internal oblique
muscle is seen fanning out to form the roof of the inguinal canal. The superior
fibers are oriented perpendicular to the external oblique aponeurosis; however,
the lower fibers run parallel with it, as they course toward the pubic bone
(Fig. 37-8).
Continuing posteriorly through the inguinal canal, the
transversus abdominis muscle is encountered deep to the inguinal ring. It arises
from the iliac crest, iliopsoas fascia, thoracolumbar fascia, and lower six
costal cartilages. Regardless of site of origin, the fibers run in a lateral to
medial fashion and it becomes less muscular and more aponeurotic medial, where
it contributes to the rectus sheath and falx inguinalis. It is a commonly held
belief that the integrity of the transversus abdominis muscle is the most
important determinant to hernia formation. As its fibers contract, the arch of
the transversus abdominis closes off the internal inguinal ring, thereby serving
as a shutter mechanism. One layer deep to the transversus abdominis is the
anterior and posterior lamina of transversalis fascia. Inferior to the arcuate
line, the posterior covering of the anterior abdominal wall consists only of
transversalis fascia, as the fascia of the external and internal oblique muscles
fans out anteriorly to constitute the anterior layer of the rectus sheath. Deep
to the transversalis fascia, the next layer encountered is the preperitoneal
areolar tissue and fat. Dissection of this tissue and progression through the
next layer, the peritoneum, allows one to enter into the peritoneal space.
Therefore, the preperitoneal space is in actuality a potential space, bordered
by the peritoneum on the deep aspect and transversalis fascia
superficially.
The inferior epigastric vessels are best visualized from a
posterior approach. The inferior epigastric artery is responsible for the blood
supply to the rectus abdominis and connects the vasculature of the upper
extremity to the lower extremity. The internal thoracic artery offshoots to form
the superior epigastric artery, which anastomoses with the inferior epigastric
artery, and is derived from the external iliac artery. The epigastric veins run
with the arteries within the rectus sheath, posterior to the rectus muscles.
Inspection of the internal inguinal ring will reveal the deep location of the
inferior epigastric vessels. Inguinal hernias that protrude lateral to the
inferior epigastric vessels, through the deep inguinal ring, are referred to as
indirect inguinal hernias. Direct hernias, on the contrary, are
protrusions medial to the inferior epigastric vessels, in Hesselbach's triangle.
The borders of the triangle are as such: the inguinal ligament forms the
inferior margin, the edge of rectus abdominis is the medial border, and the
inferior epigastric vessels are the superior or lateral border.
From an anterior perspective, the femoral space can be
visualized below the inguinal ligament. The iliopectineal arch is a fibrous band
of fused iliac and psoas fascia that subdivides the space beneath the inguinal
ligament into a lateral muscular space, housing the iliopsoas, femoral nerve,
and lateral femoral cutaneous nerve, and a medial vascular space, containing the
femoral vessels and femoral branch of the genitofemoral nerve. In addition to
these components, the vascular space also houses a medial potential space known
as the femoral canal and is the site of possible femoral hernia
formation. The canal is shaped like a cone pointed inferiorly, extending to the
fossa ovalis; the opening of the fascia latte for the great saphenous vein. The
femoral ring is bordered by sturdy structures that lend to its inflexibility.
The posterior boundary consists of the iliacus fascia and Cooper's ligament, and
the anterior boundary is the iliopubic tract and inguinal ligament, internally
and externally, respectively. Medially, the border is made up of the aponeurosis
of transversus abdominis and the transversalis fascia and laterally, the canal
is bordered by the femoral vein and its connective tissue. Normal contents of
the femoral canal include areolar preperitoneal tissue and fat and lymph nodes,
most notably the node of Cloquet at its upper end. The distal end of the canal
is closed by fatty tissue called the septum femorale. Once the integrity
of this septum is lost, femoral herniation occurs. Due to its small size and
limited flexibility, the femoral ring is usually the site of incarceration.
Reduction of incarcerated contents of a femoral hernia can thus be effected by
splitting the inguinal ligament.
Posterior Perspective
Since laparoscopic procedures have been adapted as a
treatment for inguinal hernias, surgeons have been required to reconceptualize
the groin anatomy from the posterior perspective (Fig. 37-9). The large visual
field and familiarity with intra-abdominal anatomy result in easier
identification of the posterior groin region when inguinal hernias are
approached intraperitoneally compared to the preperitoneal approach. Initial
points of reference intraperitoneally are the five peritoneal folds, bladder,
inferior epigastric vessels, and psoas muscle (Fig. 37-10). Beginning at the
midline, the median umbilical fold can be easily identified in the lower
midline. The fold represents the fibrous remnant of the fetal allantois, but may
persist in the adult as a patent urachus. As one follows the median peritoneal
fold from the umbilicus inferiorly, one encounters the pubic symphysis and
bladder. Radiating down bilaterally, just lateral to this fold, is the medial
umbilical fold, which represents the obliterated portion of the fetal umbilical
artery. Less likely, a superior vesicular artery will persist within this fold,
supplying the superior and lateral edge of the bladder, which is often found
immediately medial to the medial umbilical fold, adjacent to the lateral edge of
the bladder. Lateral to the medial umbilical ligament, the paired lateral
umbilical fold contains the inferior epigastric vessels. The inferior epigastric
artery is the lateral border of Hesselbach's triangle and thus provides a useful
landmark to differentiate between direct and indirect hernias. A defect medial
to the inferior epigastric vessels is considered direct, whereas a lateral
defect is an indirect hernia. The type of hernia also can be elucidated by
referring to the series of depressions that exist between the peritoneal folds.
Progressing from midline laterally, one can identify the supravesical, medial,
and lateral fossae. The supravesical fossa is found between the median and
medial umbilical ligaments and leads to hernias of the same name. The medial
fossa is located between the medial and lateral umbilical folds and is the site
of direct hernias. The lateral fossa is found lateral to the lateral umbilical
ligament and is the site of the internal inguinal ring and thus the location for
indirect inguinal hernias. The superficial inguinal ring is not visualized from
the peritoneal perspective. Most laterally, the psoas muscle is seen coursing
inferiorly along the retroperitoneum. The anterior superior iliac spine is not
readily apparent, but may be elucidated by palpating outside the abdomen.
Identification of the internal inguinal ring then permits identification of the
spermatic cord. Further inferior to the cord, the iliac vessels are identified
deep to the peritoneum. Two potential spaces exist deep to the peritoneum, and
these are encountered once the peritoneal flap is created. Between the
peritoneum and the posterior lamina of the transversalis fascia is Bogros's
space. This area contains preperitoneal fat and areolar tissue. A less prominent
space exists between the posterior and anterior laminae of the transversalis
fascia termed the vascular space, as this is the location of the inferior
epigastric vessels.
Once the peritoneum is reflected to expose Bogros's space,
the pertinent structures of preperitoneal inguinal anatomy can be identified.
The most medial aspect of the preperitoneal space, that which lies superior to
the bladder, is alternately known as the Retzius space. The pubic
symphysis is identified by its midline location, white periosteum, and rigidness
to palpation. The vasculature of the groin is much more apparent from the
posterior perspective than from the anterior perspective. The inferior
epigastric vessels are found in the same longitudinal plane as the iliac
vessels. A common finding is the corona mortis, which is found overlying
Cooper's ligament and represents a connection between the inferior epigastric
and obturator vessels. The deep circumflex iliac vessels arise from the external
iliac vessels and must be protected, as they may be intimately associated with
the medial portion of the iliopubic tract. Exposure of the iliac vessels allows
identification of the genital branch of the genitofemoral nerve as it courses
with the external iliac artery. At the internal inguinal ring, the nerve joins
the spermatic cord as it enters the inguinal canal.
The femoral branch of the genitofemoral nerve is found
lateral to the genital branch and is seen leaving the retroperitoneum underneath
the iliopubic tract. Also found laterally, and sometimes in association with the
femoral branch of the genitofemoral nerve, is the lateral cutaneous nerve of the
thigh. After emerging from the lateral edge of the psoas muscle, it, too, leaves
the retroperitoneum inferior to the iliopubic tract to innervate the
anterolateral skin of the thigh. The femoral nerve is not routinely seen during
laparoscopic inguinal hernia repair but can be demonstrated lateral to the
external iliac vessels between the iliacus and psoas muscles. The nerve courses
beneath the iliopubic tract and inguinal ligament as it enters the thigh. The
iliohypogastric and ilioinguinal nerves are more easily demonstrated via the
anterior perspective because they do not cross into the operative space
established by the preperitoneal approach.
The structures of the spermatic cord come together shortly
before the cord enters through the internal inguinal ring. The vas deferens is
of special note as it courses cephalad out from the pelvis and then crosses the
inferior epigastric arteries to enter the spermatic cord inferomedially.
Slightly inferior to the internal inguinal ring, the iliopubic tract is
identified as it attaches to the iliac crest. On the medial side of the internal
inguinal ring, Cooper's ligament can be demonstrated inserting inferolaterally
into the pubic ramus. The pectineal ligament can also be identified on the
medial aspect of the inferior epigastric vessels, along with the medial aspect
of the femoral ring. The remainder of the boundaries of the femoral ring are
also visualized. From the posterior perspective, this includes the iliopubic
tract superiorly, Cooper's ligament inferiorly, and the femoral vein
laterally.
The posterior perspective also allows excellent
appreciation of the myopectineal orifice of Fruchaud (Fig. 37-11). The arch of
the internal oblique muscle and transversus abdominis muscle constitute the
superior margin, the iliopsoas muscle the lateral margin, the lateral edge of
rectus abdominis medially, and the pubic pecten medially. The iliopubic tract
divides the orifice into a superior portion housing the spermatic cord and an
inferior portion containing the iliac vessels. The posterior perspective has
also resulted in the characterization of important areas to avoid, known as the
triangle of doom, triangle of pain, and the circle of death
(Fig 37-12).17 The triangle of doom is bordered medially by the vas
deferens and laterally by the vessels of the spermatic cord, thereby pointing
its apex superiorly. The contents of the space include the external iliac
vessels, deep circumflex iliac vein, femoral nerve, and genital branch of the
genitofemoral nerve. The triangle of pain can be conceptualized as the space
bordered by the iliopubic tract and gonadal vessels. The structures within this
space include nerves such as the lateral femoral cutaneous, femoral branch of
the genitofemoral, and femoral. The circle of death is a vascular continuation
formed by the common iliac, internal iliac, obturator, aberrant obturator,
inferior epigastric, and external iliac vessels. Basic knowledge of the
boundaries of these triangles allows one to avert the dangers associated with
injury to their contents.
Classification
A number of classification systems have been developed
relating to inguinal hernias. The classification systems allow for
standardization in comparing outcomes of various hernias, yet their clinical
significance to date is limited. A common clinical classification system relates
to location and subdivides hernias into indirect, direct, and femoral, although
this system does not take into account the complexity of the hernia. Even this
system has undergone considerable transformation with the concept of the
myopectineal orifice of Fruchaud. Instead of examining the various locations of
herniation independently, Fruchaud determined that a common site of weakness,
the transversalis fascia, predisposes to all three hernias. With hernia
treatment directed at restoring the integrity of this area, recurrences of all
three hernias can be reduced. An ideal classification system would also be able
to preoperatively stratify hernias and allow for the most appropriate approach
to repair, rather than making management decisions based on intraoperative
findings. However, preoperative classification relies heavily upon physical
examination and the inherent subjectivity of it. Intraoperative classification
is also complicated by the fact that certain components of an inguinal hernia
cannot be assessed via the laparoscopic method.
A number of authors, including Rutkow, Robbins, Gilbert,
Nyhus, and Schumpelick, have attempted to devise a standardized classification
system. Gilbert's classification requires intraoperative assessment and divides
hernias into five types, three indirect and two direct (Table 37-4). Type 1
hernias have a small internal ring, type 2 have a moderately dilated internal
ring, and type 3 have a ring that is greater than two fingerbreadths. A type 4
direct hernia involved complete disruption of the inguinal floor, and type 5
represented direct hernias with a small diverticular opening of no more than one
fingerbreadth.18 Rutkow and Robbins further expanded the Gilbert
classification to include a type 6 pantaloon hernia, which is a combination of a
direct and indirect hernia sac, and type 7 femoral hernia.19
Table 37-4 Gilbert Classification System
|
|
| Type 1 |
Small, indirect |
| Type 2 |
Medium,
indirect |
| Type 3 |
Large, indirect |
| Type 4 |
Entire floor,
direct |
| Type 5 |
Diverticular,
direct |
| Type 6 |
Combined
(pantaloon) |
| Type 7 |
Femoral |
|
|
The Nyhus classification is more detailed and assesses not
only the location and size of the defect, but also the integrity of the inguinal
ring and inguinal floor (Table 37-5). Consequently, this is one of the most
widely used classifications. The system divides hernias into four types, with
three subgroups for type III. A type I hernia has a normal size and
configuration of the internal ring and occurs primarily as a congenital hernia.
Type II hernias have a distorted and enlarged internal ring, without
encroachment into the inguinal floor, and small hernia sac. Type IIIA hernias
include small- to moderate-sized direct hernias without any sac component
through the internal ring. Type IIIB hernias consist of large indirect hernias
with defects that encroach on the inguinal canal floor, usually secondarily
affecting the structure of the floor. Femoral hernias are classified as type
IIIC, and recurrent inguinal hernias are type IV, with A representing direct, B
indirect, C femoral, and D any combination of the previous three.20
Despite its general acceptance, the Nyhus classification scheme is limited by
its subjectivity in assessment of distortion of the inguinal ring and posterior
floor, especially laparoscopically.
Table 37-5 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 |
|
|
A third major classification system was created by
Schumpelick and enjoys greater application in Europe compared to North America.
The major feature is the addition of orifice sizing to traditional systems. An L
represents a lateral indirect site, M represents medial direct, and F for
femoral. The defects are then graded according to size with type I being <1.5
cm in diameter, type II being 1.5 to 3 cm, and type III being >3
cm.21 Although the system purports to be more objective, differences
in the extent of abdominal distention during pneumoperitoneum may affect
measurements. A significant amount of other classification systems exist,
although no single system has been widely embraced by all surgeons. Future
systems will have to take into account ease of use, objectivity, and account for
varying anatomic perspectives between open and laparoscopic
surgery.
|
Diagnosis
History
Inguinal hernias present along a spectrum of scenarios.
These range from incidental findings to symptomatic hernias to surgical
emergencies such as incarceration and strangulation of hernia sac contents.
Asymptomatic inguinal hernias are frequently diagnosed incidentally on physical
examination or may be brought to the patient's attention as an abnormal bulge.
In addition, these hernias can be identified intra-abdominally during
laparoscopy. Inspection of the pelvis following mobilization of intestinal
contents into the upper abdomen will reveal the myopectineal orifice and allow
facile identification of the peritoneum herniating through the direct, indirect,
or femoral space.
Patients who present with a symptomatic groin hernia will
frequently present with groin pain. Less commonly, patients will present with
extrainguinal symptoms such as change in bowel habits or urinary symptoms.
Regardless of size, an inguinal hernia may impart pressure onto nerves in the
proximity, leading to a range of symptoms. These include generalized pressure,
local sharp pains, and referred pain. Pressure or heaviness in the groin is a
common complaint, especially at the conclusion of the day, following prolonged
activity. Sharp pains tend to indicate an impinged nerve and may not be related
to the extent of physical activity performed by the patient. Lastly, neurogenic
pains may be referred to the scrotum, testicle, or inner thigh. Questions also
should be directed to elucidating the extrainguinal symptoms. A change in bowel
habits or urinary symptoms may indicate a sliding hernia consisting of
intestinal contents or involvement of the bladder within the hernia sac.
Important considerations of the patient's history include
duration and progressiveness of the symptoms. Hernias will often increase in
size and content over a protracted time. Much less commonly, a patient will
present with a history of acute inguinal herniation following a strenuous
activity. However, it is more likely that an asymptomatic, previously unknown,
inguinal hernia became evident once the patient experienced symptoms associated
with the circumstances of the acute event. Notwithstanding the type of
presentation, specific questions should be focused as to whether the hernia is
reducible. Oftentimes, patients will reduce the hernia by pushing the contents
of the bulge back into the abdomen, thereby providing temporary relief. As the
size of a hernia increases and a larger amount of intra-abdominal contents fill
the hernia sac, the bulge may become harder to reduce.
Physical
Although the history may be tremendously indicative of an
inguinal hernia, the physical examination is essential to forming the diagnosis.
A significant drawback exists in morbidly obese patients, where delineation of
external groin anatomy is difficult and may obscure the findings of a groin
hernia. Ideally, the patient should be examined in a standing position, with the
groin and scrotum fully exposed. The standing position has the advantage over
the supine position in that intra-abdominal pressure is increased, and thereby,
the hernia can be more easily elicited. Inspection is performed first, with the
goal of identifying an abnormal bulge along the groin or within the scrotum. If
an obvious bulge is not detected, physical examination is performed to confirm
the presence of the hernia.
Palpation is performed by placing the index finger into the
scrotum, aiming it toward the external inguinal ring (Fig. 37-13). This allows
the inguinal canal to be inspected. The patient is then asked to cough or bear
down (i.e., Valsalva's maneuver) to protrude the hernia contents. Reproduction
of patient symptoms, namely vague, generalized pressure sensations, will not
usually be reproduced by these maneuvers, as they are a product of prolonged
pressure on the cord contents. However, a Valsalva's maneuver will reveal an
abnormal bulge and allow the clinician to determine whether the bulge is
reducible or not. Examination of the contralateral side affords the clinician
the opportunity to compare the extent of herniation between sides. This is
especially useful in the case of a small hernia. The magnitude of the bulge on
the affected side can be compared to the normal bulging of muscle on the
nonaffected side, when the abdomen is placed under strain. However, the results
may be misleading if there is a latent contralateral hernia that is discovered
during this examination.
|
Certain techniques of the physical examination have
classically been used to differentiate between direct and indirect hernias. The
inguinal occlusion test involves placement of a finger over the internal
inguinal ring and the patient is instructed to cough. If the cough impulse is
controlled, then the hernia is indirect. If the cough impulse is still manifest,
the hernia is direct. As well, with a finger in the inguinal canal, the cough
impulse can be used to determine the type of hernia. If the cough impulse is
felt on the fingertip, the hernia is indirect; if felt on the dorsum of the
finger, it is deemed direct. However, when results of clinical examination are
compared against operative findings, there is a probability somewhat higher than
chance (i.e., 50%) of correctly diagnosing the type of hernia.22,23
Therefore, the utility of these tests should not be used to diagnose the type of
inguinal hernia insomuch as they should be used to determine the presence or
absence of one.
A further challenge to the physical examination is the
identification of a femoral hernia. The anatomic position of a femoral hernia
dictates that it should be palpable below the inguinal ligament, lateral to the
pubic tubercle. As a consequence of increased subcutaneous tissue, a femoral
hernia may be missed or misdiagnosed as a hernia of the inguinal canal. In
contrast, a prominent fat pad in a thin patient may prompt an erroneous
diagnosis of femoral hernia, otherwise known as a femoral
pseudohernia.
In addition to inguinal hernia, a number of other diagnoses
may be considered in the differential of a groin bulge (Table 37-6). The
diagnosis is ambiguous; radiologic investigation may provide the answer.
Table 37-6 Differential Diagnosis of Groin Hernia
|
|
| Malignancy |
| Lymphoma |
| Retroperitoneal
sarcoma |
| Metastasis |
| Testicular
tumor |
| Primary
testicular |
| Varicocele |
| Epididymitis |
| Testicular
torsion |
| Hydrocele |
| Ectopic
testicle |
| Undescended
testicle |
| Femoral artery aneurysm
or pseudoaneurysm |
| Lymph node |
| Sebaceous cyst |
| Hidradenitis |
| Cyst of the canal of Nuck
(female) |
| Saphenous varix |
| Psoas abscess |
| Hematoma |
| Ascites |
|
|
Imaging
A number of situations can make the usually straightforward
diagnosis of inguinal hernia ambiguous. These scenarios include obese patients,
hernias that cannot be elicited on physical examination, and recurrent inguinal
hernias. In these situations, radiologic investigations may be used as an
adjunct to history and physical examination. The most common radiologic
modalities include ultrasonography (US), computed tomography (CT), and magnetic
resonance imaging (MRI). Each technique has certain advantages over physical
examination alone; however, each also is associated with potential
pitfalls.
Ultrasound is the least invasive technique and does not
impart any radiation to the patient. Anatomic structures can be more easily
identified by the presence of bony landmarks; however, because there are few in
the inguinal canal, other structures such as the inferior epigastric vessels are
used to define groin anatomy. Positive intra-abdominal pressure is used to
elicit the herniation of abdominal contents. Movement of these contents is
essential to making the diagnosis with US, and lack of this movement may lead to
a false negative. In thin patients, normal movement of the spermatic cord and
posterior abdominal wall against the anterior abdominal wall may lead to
false-positive diagnoses of hernia.24
CT and MRI provide static images that are able to delineate
the groin anatomy and demonstrate not only the presence of groin hernias, but
also rule out differential diagnoses that may cloud the clinical picture (Fig.
37-14). Although CT scan is useful in ambiguous clinical presentations, little
data exist to support its routine use in diagnosis. The use of MRI in assessing
groin hernias was examined in a group of 41 patients scheduled to undergo
laparoscopic inguinal hernia repair. Preoperatively, all patients underwent US
and MRI. Laparoscopic confirmation of the presence of inguinal hernia was deemed
the gold standard. Physical examination was found to be the least sensitive,
whereas MRI was found to be the most sensitive. False positives were low on
physical examination and MRI (one finding), but higher with US (four findings).
With further refinement of technology, radiologic techniques will continue to
improve the sensitivity and specificity rates of diagnosis, thereby serving a
supplementary role in cases of uncertain diagnosis.
Anesthesia
Local, regional, and general anesthesia are all viable
options for open anterior hernia repairs. Laparoscopic repairs, on the other
hand, usually are performed using general anesthesia for optimal abdominal
expansion and patient comfort. This limitation of laparoscopic surgery becomes a
consideration in high-risk patients that cannot tolerate general anesthesia and
the effects of pneumoperitoneum. In contrast, there are relatively few side
effects of local anesthesia, which can facilitate operative tolerance by the
patient, especially when combined with an IV sedative or anxiolytic agent.
Local anesthesia is applied by the surgeon before the
initial groin incision. Common anesthetic agents include lidocaine and the
longer-acting bupivacaine, both with optional epinephrine. Patients with a
history of coronary artery disease have a relative contraindication to
epinephrine use. The maximum dose should be calculated according to the
patient's weight during preparation of the injection. In advance of the initial
incision, usually before the prep and drape, a variable amount of anesthetic is
injected one fingerbreadth medial and inferior to the anterior superior iliac
spine to block the ilioinguinal nerve. In addition, anesthetic is injected along
the cutaneous course of the skin incision and underlying subcutaneous tissue.
The remaining amount is reserved for repeated applications to affected areas
during the course of the operation. A combination of the two agents provides for
a quick onset and prolonged control of pain, in the range of 18 hours.
Regional anesthesia, such as epidural, is another option
reserved for patients that cannot tolerate general anesthesia. It also has a
greater margin of patient comfort. Additional advantages of local and regional
anesthesia include the ability of the patient to cough or Valsalva to test the
repair. The versatility of anesthesia choices is a common argument for
proponents of open inguinal hernia repairs. Nonetheless, the majority of
procedures are performed using general anesthesia, which provides the greatest
margin of patient comfort of all three choices. Advances in perioperative care
have allowed for extensive general anesthesia use in an ambulatory surgery
setting. Long- or short-acting local anesthetics can be applied to the incisions
at the end of the procedure to prolong pain control. Common cardiorespiratory
complications of anesthesia include myocardial depression, infarct, and
aspiration pneumonia. The risk of these complications is reduced by using local
anesthesia; however, anesthesiologists may prefer to completely sedate the
patient and thereby control the airway. It should be noted that most procedures
using only local anesthesia are performed at specialty hernia
centers.
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Treatment
The treatment of inguinal hernias can be subdivided
according to approach (i.e., open vs. laparoscopic). Open inguinal hernias can
be further subdivided according to whether the repair is performed anterior or
posterior to the inguinal floor. A large number of open inguinal hernia repairs
have been described over time; however, the most commonly performed and
clinically pertinent procedures will be described herein.
Open Approach
Before the widespread use of prosthetic material, inguinal
hernia repairs were based on restoring tissue strength through the use of
sutures. Upon the introduction of prosthetics in the tension-free repair, these
procedures came to be known as tension repairs; however, this would imply
that these procedures do not adhere to basic surgical principles of avoiding
tension between tissues. Therefore, these will be referred to as tissue
repairs. Despite the advantages of the tension-free prosthetic repair,
tissue repairs occupy an important place in the choice of inguinal hernia
repair, especially in situations where prosthetic material is contraindicated.
This includes a contaminated operative field or concern regarding possible
azoospermia secondary to long-term effects of mesh on the vas
deferens.25
Exposure of the inguinal region is common to open
approaches to inguinal hernia repair. An oblique or horizontal incision is
performed over the groin (Fig. 37-15). A point two fingerbreadths inferior and
medial to the anterior superior iliac spine is chosen as the most lateral point
of the incision. It is then progressed medially for approximately 6 to 8 cm.
Electrocautery is then used to divide the subcutaneous tissue. Fascia of Camper
is not routinely encountered; however, Scarpa's fascia generally is identified
and then divided, thereby exposing the aponeurosis of the external oblique
muscle. A vein coursing in a vertical fashion through the subcutaneous tissue
frequently is encountered and is ligated and divided between hemostat clamps.
The fibers of the external oblique muscle are then sharply divided parallel to
the direction of fibers. Metzenbaum scissors are then advanced immediately
beneath the fibers, laterally and then medially toward the external inguinal
ring, and spread as they are retracted to create a space and avoid inadvertent
dissection of the ilioinguinal nerve. The scissors are then used to incise the
aponeurosis, splitting the external inguinal ring, exposing the inguinal canal
and its contents. The aponeurosis is divided superior to the inguinal ligament
as consideration should be made for its reapproximation once the repair is
complete.
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Mobilization of the Cord Structures
Hemostat clamps are then applied to the superior and
inferior edges of the aponeurosis and elevated from the inguinal canal. Blunt
dissection is then performed to separate the superior flap of the external
oblique aponeurosis from the internal oblique muscle. Likewise, the inferior
flap of the external oblique aponeurosis is bluntly dissected to reveal the
shelving edge of the inguinal ligament. The iliohypogastric and ilioinguinal
nerves are identified and may be retracted from the operative field by placing a
hemostat beneath their course and then grasping one of the edges of the
aponeurosis. Some surgeons routinely divide these nerves to avoid possible
entrapment; however, the sequelae involve permanent paresthesia to sites of
their cutaneous distribution. The pubic tubercle is then identified and the
surgeon's index finger and thumb are placed around the cord as it passes the
tubercle. A Penrose drain or metal cord ring may then be placed around the cord
and its contents to permit its elevation from the floor of the inguinal canal.
With the cord elevated at the external inguinal ring, cremasteric fibers are
visualized connecting the floor of the inguinal canal to the posterior aspect of
the cord. The cremasteric fibers can then be divided bluntly or through the use
of electrocautery to initiate skeletonization of the cord. Once the cremasteric
fibers are completely divided between the external and internal inguinal rings,
the floor of the inguinal canal can be fully assessed for direct hernias. Care
must be taken to avoid injury to cord structures during the division of the
cremasteric muscle.
Identification and Reduction of the Sac
With the contents of the inguinal canal completely
encircled, identification of cord contents and the hernia sac can be effected.
Direct hernias will become evident as the floor of the inguinal canal is
dissected. Even in tension-free repairs, the floor of the inguinal canal may be
imbricated with stitches to reduce the direct hernia sac. An indirect hernia sac
will generally be found on the anterolateral surface of the spermatic cord. In
addition to sac identification, the vas deferens and vessels of the spermatic
cord must be identified to allow dissection of the sac from the cord. At the
leading edge of the sac, the two layers of peritoneum will fold upon themselves
and reveal a white edge, which may help in the identification of the sac. This
peritoneum can then be grasped with a tissue forceps and bluntly dissected from
the cord. The dissection is carried proximally toward the deep inguinal
ring.
The reduction of the hernia sac into the preperitoneal
space is commonly known as high ligation of the sac. Some surgeons will
routinely open the sac and inspect it to ensure there is no incarceration of
intra-abdominal contents. As well, the decision must be made whether to excise
the sac at the internal inguinal ring or simply invert it into the
preperitoneum. Both methods are effective in reducing the sac; however, in a
large prospective randomized study, patients undergoing high ligation and
excision of the sac had significantly increased postoperative pain in the first
week.26 A densely adherent sac, which may result in injury to cord
structures, does not necessarily deserve dissection; however, division at the
internal inguinal ring is necessary. Likewise, an inguinal hernia sac that
extends into the scrotum may require division within the inguinal canal.
Attempts to reduce such sacs may be met with postoperative complications related
to injury of the pampiniform plexus, including testicular atrophy and
orchitis.
Wound Closure
Once the reconstruction of the inguinal canal is complete,
the cord contents are returned to their anatomic position. The external oblique
aponeurosis is then reapproximated. A useful starting position is at the
external inguinal ring. Using an absorbable suture, the external inguinal ring
is reconstructed and the external oblique fascia is then closed using a running
stitch that progresses laterally. Avoidance of an overly constricting external
ring will prevent compression of cord structures at that point. However, it
should be small enough to contain the contents of the inguinal canal and prevent
a future false-positive diagnosis of recurrent hernia. Scarpa's fascia may then
be closed with a series of interrupted absorbable sutures. Lastly, skin is
closed with a subcuticular stitch to preserve cosmesis of the incision.
Anterior Repairs, Nonprosthetic
Before the introduction of mesh prostheses, open anterior
inguinal hernia repairs were performed by reapproximating tissue using only
sutures. Despite their shortcomings, specific procedures such as the Bassini,
Shouldice, and McVay repair continue to occupy a minor, yet important role in
the overall treatment of inguinal hernias. The introduction of the Bassini
repair was superior to previously performed procedures in that, not only was the
hernia reduced and the defect oversewn, but now an attempt was made to
reconstruct the site of weakness, although these tissue-based repairs tend to
place tension on the reconstructed tissue. The Shouldice repair is an exception
because the multilayer reconstruction distributes the tension, effectively
resulting in a tension-free repair. Hernia exposure and reduction are common to
all open anterior repairs; however, the mode of restoration of inguinal canal
integrity differs according to procedure.
Bassini Repair
The Bassini repair was a major advancement in the treatment
of inguinal hernias owing to significantly reduced recurrence rates as compared
to other operations of the day. Current use of the Bassini repair is limited
because other tissue-based operations such as the Shouldice repair have
demonstrated lower recurrence rates. The importance of the Bassini repair lies
in the paradigm shift it promoted, which included dissection of the spermatic
cord, dissection of the hernia sac with high ligation, and extensive
reconstruction of the floor of the inguinal canal (Fig. 37-16). Following
division of the cremasteric muscle and ligation of the hernia sac deep to the
internal inguinal ring, the transversalis fascia is incised from the pubic
tubercle to the internal inguinal ring, thereby entering the preperitoneal
space. Preperitoneal fat is bluntly dissected from the upper margin of the
posterior side of the transversalis fascia to permit adequate tissue
mobilization. A triple-layer repair is then performed to restore integrity to
the floor. The medial tissues, including the internal oblique muscle,
transversus abdominis muscle, and transversalis fascia, are fixed to the
shelving edge of the inguinal ligament and pubic periosteum with interrupted
sutures. The lateral border of the repair is the medial border of the internal
inguinal ring, which subsequently is reinforced by the repair. Adoption of the
Bassini technique in North America resulted in injury to neurovascular
structures and high recurrence rates because the posterior floor was not
routinely opened. Nevertheless, the significant advances promulgated by Bassini
still resulted in a recurrence rate that could be further improved. Numerous
modifications of the technique by successive surgeons accomplished a lower
recurrence rate, namely with the addition of the relaxing incision and the
Shouldice technique. Current use of the Bassini technique is limited, although a
modification may be useful in large direct hernias approached via an open
approach. In these cases, imbrication of the posterior floor may be added to a
tension-free repair with mesh
Shouldice Repair
The principles of the Bassini repair were revitalized
within the Shouldice repair, resulting in superior recurrence rates. Although
the Shouldice repair is generally grouped with open tissue-based repairs, its
success rates are equivalent to that of tension-free repairs in many studies
comparing the two approaches. As with the Bassini repair, the primary tenets of
the procedure involve extensive dissection and reconstruction of inguinal canal
anatomy. The use of a continuous suture in multiple layers resulted in the dual
advantage of distributing tension over several layers and preventing subsequent
herniation between interrupted sutures (Fig. 37-17). Original descriptions of
the Shouldice technique involved the use of a stainless steel wire; however,
modern modifications have resulted in the use of a synthetic nonabsorbable
suture. With the posterior inguinal floor exposed, an incision in the
transversalis fascia is performed between the pubic tubercle and internal ring.
Care is taken to avoid injury to any preperitoneal structures, and these are
bluntly dissected to mobilize the upper and lower fascial flaps. The first layer
of repair begins at the pubic tubercle where the iliopubic tract is sutured to
the lateral edge of the rectus sheath, then progressing laterally. The inferior
flap of the transversalis fascia, which includes the iliopubic tract, is sutured
continuously to the posterior aspect of the superior flap of the transversalis
fascia until the internal ring is encountered. At this point, the internal ring
has been reconstituted. The suture is not tied here, but rather is continued
back upon itself in the medial direction. At the internal ring, the second layer
is the reapproximation of the superior edge of the transversalis fascia to the
inferior fascial margin and the shelving edge of the inguinal ligament. The
suture is then tied to the tail of the original stitch. A third suture is
started at the tightened inguinal ring, joining the internal oblique and
transversus abdominis aponeuroses to external oblique aponeurotic fibers just
superficial to the inguinal ligament. This layer is continued to the pubic
tubercle where it reverses upon itself to create a fourth suture line, which is
similar and superficial to the third layer. Unique to this operation is the
routine division of the genital branch of the genitofemoral nerve. The
consequence of loss of skin sensation is countered by the observed decrease in
recurrence rate at the pubic tubercle. The Shouldice technique is readily
apparent in common practice, especially in specialized hospitals treating
inguinal hernias.
McVay Repair
The advantage of the McVay (Cooper's ligament) repair is
the ability to address both inguinal and femoral canal defects. Femoral hernias
that are approached via a suprainguinal ligament approach, or situations where
the use of prosthetic material is contraindicated, are amenable to this type of
repair. The operation was popularized by McVay, who also added the concept of
the relaxing incision as a tension reducing maneuver (Fig. 37-18). Once the cord
has been isolated, a transverse incision is performed through the transversalis
fascia, thereby entering the preperitoneal space. A small amount of dissection
of the posterior aspect of the fascia is performed to allow mobilization of the
upper margin of the transversalis fascia. The floor of the inguinal canal is
then reconstructed to restore its strength. Cooper's ligament is identified
medially, and it is bluntly dissected to expose its surface. The upper margin of
the transversalis fascia is then sutured to Cooper's ligament. The repair is
continued laterally along Cooper's ligament, occluding the femoral canal.
Once the femoral canal has been passed, a transition stitch
is performed by now suturing the transversalis fascia to the inguinal ligament.
The transition stitch helps obliterate the femoral canal, but more importantly,
avoids injury to the femoral vessels. The transversalis fascia is subsequently
sutured to the inguinal ligament, the lateral margin being the internal inguinal
ring, which consequently undergoes transformation to a smaller, tighter ring.
The repair can be performed using either interrupted sutures or a continuous
stitch. An essential component of the procedure is the relaxing incision, which
helps reduce the considerable amount of tension that normally results. Before
suturing the transversalis fascia to Cooper's and the inguinal ligament, an
incision in the anterior rectus sheath is made. The incision begins at the pubic
tubercle and is extended superiorly for approximately 2 to 4 cm.
Potential consequences of the relaxing incision include
increased postoperative pain and less likely herniation at the anterior
abdominal wall. Disadvantages of routinely performing the McVay Cooper's
ligament repair include elevated recurrence rates due to the tissue-based nature
of the operation. Furthermore, the procedure requires extensive dissection and
may result in injury to the underlying femoral vessels.
Anterior Repairs, Prosthetic
Outside of specialized centers dealing with inguinal
hernias, recurrence rates of tissue-based repairs continued to be high, owing to
the tension placed on reconstructed tissues. To circumvent this problem and
adhere to no-tension principles of effective surgical repair, mesh
herniorrhaphies were developed. The addition of a mesh prosthesis effected a
reconstruction of the posterior inguinal canal, without placing tension on the
floor itself, hence a tension-free repair, as championed by Lichtenstein.
Further refinements have included the addition of a plug through the internal
ring, resulting in the plug and patch repair. The consistently superior
recurrence rates over the long-term, along with the ease of reproducibility of
these techniques, resulted in the wide acceptance of tension-free repairs for
inguinal hernias.
Lichtenstein Tension-Free Repair
Initial exposure and mobilization of cord structures is
identical to other open approaches. Particular attention must be paid to blunt
dissection of the inguinal canal to expose the shelving edge of the inguinal
ligament and pubic tubercle, as well as provide a large area for mesh placement.
Unlike the tissue-based repairs, the Lichtenstein repair does not include
routine division of the transversalis fascia, thereby preventing the
identification of a latent femoral hernia. However, in the case where a
clinically significant hernia is not visualized upon entrance into the inguinal
canal, an argument can be made to enter the preperitoneal space and evaluate the
femoral canal. The lack of inguinal floor division also indicates that the
internal inguinal ring is not reconstructed using canal structures (Fig. 37-19).
Instead, the floor and internal ring are reinforced through the application of
the mesh.
The mesh is rectangular in shape, with a rounded edge at
its apex, corresponding to the medial edge. At the other end, the mesh will be
split to accommodate the spermatic cord. The mesh prosthesis must be large
enough to adequately cover the posterior wall of the inguinal canal and can be
sized accordingly when placed into the field. The rounded edge is attached to
the anterior rectus sheath just medial to the pubic tubercle, ensuring that
there is an adequate overlap medially to prevent recurrence. The suture is then
continued in a running fashion to secure the mesh around the pubic tubercle.
Care must be taken to avoid placing sutures directly into the periosteum of the
pubic tubercle, which may result in persistent postoperative pain. The inferior
margin of the mesh is then sutured to the shelving edge of the inguinal
ligament, as the repair is continued laterally. The stitch is then tied at the
internal ring. The mesh is then tailored to fit around the cord at the internal
ring. The slit in the lateral end of the mesh may require expansion to
accommodate the cord and prevent strangulation of cord contents. The superior
and inferior flaps of the prosthesis are then placed around the base of the
cord, lateral to the internal ring and near the anterior superior iliac spine,
and sutured together with a single interrupted stitch. This allows the internal
ring to be reinforced by a synthetic valve, helping to prevent recurrences of
indirect inguinal hernias.
A flap closure that is too lose may lead to higher indirect
hernia recurrences; however, one that is too tight may impart significant
pressure on the spermatic cord, leading to the injury of its contents. The
superior edge of the mesh is then fixed to the posterior aspect of the internal
oblique aponeurosis and rectus sheath, using either interrupted or continuous
sutures. Fixation of the upper and lower margin of the mesh too superficially to
the internal and external oblique aponeuroses may shorten the superior and
inferior flaps of the external oblique aponeurosis, making closure of the
inguinal canal difficult. In the case of a femoral hernia, the inferior margin
of the mesh is sutured to Cooper's ligament medially and inguinal ligament
laterally, similar to McVay's repair. Nonabsorbable or long-term absorbable
sutures generally are used with mesh repairs.
Plug and Patch Technique
A modification of the Lichtenstein repair, known as the
plug and patch technique, was developed by Gilbert and later popularized
by Rutkow and Robbins.27 In addition to placement of the prosthesis
in a similar fashion to the Lichtenstein repair (i.e., the patch), the technique
includes placement of a prosthesis (i.e., the plug) through the internal ring
(Fig. 37-20). The internal ring is therefore reinforced by the leaflets of the
patch as well as the plug. Initial technique described rolling a flat piece of
polypropylene into a tight cylinder and placing it alongside the spermatic cord
as it passes through the internal ring. Further modifications have involved
shaping the plug into a flower or umbrella configuration, with the apex pointed
intra-abdominally, in effect serving as a preperitoneal prosthesis. Increased
abdominal pressure acts on the plug, opening its leaflets and creating a
protective valve. Original descriptions of the plug and patch procedure
emphasized a pure tension-free approach in that the plug and patch could be
placed in their anatomic positions without sutures. Normal scarring would then
fix the prostheses in place and provide reconstituted strength to the inguinal
canal. Currently, preformed plugs in various sizes are available and are usually
fixed to the margins of the internal ring with one or several interrupted
sutures.28 Direct defects may also be plugged; however, in the
absence of inguinal floor division and dissection, suture fixation of the plug
to the margins of the defect is necessary. In this case, the plug is fixed to
Cooper's and the inguinal ligament inferiorly and the internal oblique
aponeurosis superiorly. Numerous modifications of the plug and patch technique
have occurred with various extents of prosthesis fixation. Considerations unique
to the plug include intra-abdominal migration and erosion into contiguous
structures.
Preperitoneal Repairs
As previously noted in the Bassini Repair section, the
preperitoneal space can be entered using the anterior approach by dividing the
transversalis fascia; however, wide exposure of the preperitoneal space is
limited. Therefore, a number of surgeons have approached the preperitoneal space
posterior to the transversalis fascia. Cheatle was the first to perform
posterior preperitoneal repair of a groin hernias, usually through a lower
midline and later using a Pfannenstiel incision. Nonprosthetic preperitoneal
repairs were also described by Nyhus; however, the superior results achieved by
mesh use lend them to historical significance only. The placement of a widely
overlapping prosthesis in the preperitoneal space using the open approach
eventually became the basis of laparoscopic surgery. The strength of the
transversalis fascia is reinforced by the addition of the prosthesis deep to it.
The perceived advantage of the preperitoneal approach is that the prosthesis can
be placed between hernia contents and the hernia defect. Furthermore, increases
in intra-abdominal pressure serve to push the mesh against the floor of the
inguinal canal, unlike in anterior mesh placement where the mesh is pushed away.
The posterior approach to preperitoneal repairs avoids entry into the inguinal
canal and permits optional closure of the hernia defect. Therefore, nerves that
course through the inguinal canal are avoided, and there is minimal manipulation
of the spermatic cord. A Pfannenstiel or lower midline incision is generally
used to gain access to the preperitoneal space, taking care not to disturb the
peritoneum. The preperitoneal space can also be accessed intra-abdominally;
however, this approach is optimal if a laparotomy is being performed for other
purposes. A notable example is a laparotomy performed for bowel obstruction that
results in the identification of an inguinal hernia as the cause of
obstruction.
Read-Rives Repair
The anterior approach to preperitoneal repairs, as
described by Read and Rives, accesses the groin using a standard groin incision
(Fig. 37-21). The transversalis fascia is incised and a wide blunt dissection of
the preperitoneal space is performed to accommodate a large prosthesis. The
spermatic cord is identified at the internal ring and dissected from the
peritoneum proximally to the pelvic portion of the vas deferens. The vas
deferens is separated from the spermatic vessels during the course of cord
parietalization. Cooper's ligament must also be identified medially and
dissected free to expose its surface. Dissection to this extent frees the
peritoneum from the iliac fossa and provides an adequate space for placement of
a large prosthesis. An unsplit piece of mesh, approximately 16 x
12 cm is then placed in the preperitoneal space over the spermatic cord,
ensuring overlap medial to Cooper's ligament, laterally to the anterior superior
iliac spine and inferiorly to the margin of the preperitoneal dissection. The
mesh is secured using three sutures, to Cooper's ligament, the pubic tubercle,
and the psoas muscle. The transversalis fascia is then reclosed, and the
inguinal canal is closed routinely as per the open approach.
Giant Prosthetic Reinforcement of the Visceral Sac
The giant prosthetic reinforcement of the visceral sac is
also known as the Rives, Stoppa, or Wantz repair, although minor
modifications exist between them. Ideal access is provided by a Pfannenstiel or
lower transverse incision, which is more medial than a standard groin incision
in anterior open approaches. The incision ranges 8 to 10 cm from the midline
laterally, above the level of the internal ring. The intent is to expose the
lateral aspect of the rectus sheath and divide it and the oblique muscles for a
distance of 10 cm. Abdominal wall muscles are then retracted to expose the
transversalis fascia, allowing it to be incised. The peritoneum is left intact
to maintain the procedure within the preperitoneal space. Wide dissection is
then performed posterior to the rectus sheath and inferior epigastric vessels
(Fig. 37-22). The dissection begins on the contralateral side of the midline and
continues laterally to beyond the anterior superior iliac spine. Inferiorly, the
peritoneum is dissected to the division of the spermatic vessels and vas
deferens. The posterior approach requires identification of Cooper's ligament
medially and the iliopubic tract running laterally. A direct hernia will be
identified and reduced during the course of initial dissection. Care must be
taken to separate the hernia sac from the overlying transversalis fascia because
an incorrect plane of dissection may be entered, resulting in dissection of the
anterior abdominal wall. Direct defects can be ignored, or conversely, the
defect can be imbricated or obliterated by suturing the transversalis fascia to
Cooper's ligament. An indirect hernia will be identified at the internal ring
and usually will require additional directed dissection. The advantage to the
preperitoneal approach is minimal interaction with the spermatic cord.
Therefore, in the case of large or densely adherent indirect hernia sacs that
pose a problem during cord parietalization, ligation of the sac may be
undertaken. The distal sac is left untouched, and the sac, at its insertion at
the internal ring, is dissected from the spermatic cord. The resulting defect in
the peritoneum is then closed to restore the peritoneal lining. Because the sac
is bilayered, it can be opened on the side not adherent to the cord and
dissected away until it can be circumferentially freed and divided.
A large mesh is then aseptically prepared for placement
into the dissected space. The width of the mesh should span a distance between
the umbilicus and anterior superior iliac spine, minus 1 cm, and the height
should be approximately 14 cm. Variations of mesh preparation include an intact
mesh vs. a slit mesh. A slit in the lateral aspect accommodates the spermatic
cord, similar to mesh placement in the Lichtenstein tension-free repair.
Splitting of the mesh creates a small defect in its integrity, which may
predispose it to a hernia recurrence. Proponents for a slit or keyhole argue
that mesh positioning is optimal and obviates the need for fixation sutures.
Fixation is an important consideration when avoiding preperitoneal structures
such as the lateral femoral cutaneous nerve and inferior epigastric vessels.
Wantz's technique advocates the placement of three absorbable sutures that
attach the superior border of the mesh to the anterior abdominal wall above the
level of the indirect or direct defect. The location of fixation sutures
includes the linea alba, linea semilunaris, and anterior superior iliac spine.
Long clamps placed along the inferior border of the prosthesis facilitate flat
placement along the inferior margin of the preperitoneal space (Fig. 37-23). The
clamps are placed along the lower corners of the mesh and one in between. The
mesh should be placed in a flat, taut position, avoiding any scrolling of the
inferior border. The medial clamp is directed into the space of Retzius, the
middle clamp over the pubic ramus and iliac vessels, and the lateral clamp is
placed into the iliac fossa to provide coverage of the spermatic cord. The
clamps are removed as the peritoneal is brought into apposition with the
prosthesis. In the case of bilateral hernias, Stoppa advocates the use of a
single large mesh spanning the area between the two anterior superior iliac
spines minus 2 cm. The height is the distance between the umbilicus and the
pubis. The large mesh requires the application of eight clamps to the lower
border to facilitate proper placement. Although the approach provides excellent
coverage and reinforcement of the preperitoneal space, postoperative pain and
recovery is a significant consideration (Fig. 37-24).
Iliopubic Tract Repair
The iliopubic tract repair was popularized by Nyhus and
Condon following extensive anatomic study detailing the importance of the
iliopubic tract. The preperitoneal approach does not allow for visualization of
the inguinal ligament; however, the iliopubic tract serves an analogous function
in the preperitoneal space by providing a strong point of fixation. The repair
combines a preperitoneal tissue-based repair with the implantation of mesh.
Access to the preperitoneum is gained through a transverse abdominal incision
two fingerbreadths above the pubic symphysis. The anterior rectus sheath is
incised and the rectus abdominis is retracted medially to expose the posterior
aspect of the sheath. The internal and external oblique muscles and the
transversus abdominis muscle are also incised to reach the transversalis fascia
(Fig. 37-25). The preperitoneal exposure and dissection is similar to other open
preperitoneal techniques. Reconstruction of the inguinal floor is then enacted
by suturing the transverse aponeurotic arch to Cooper's ligament and the
iliopubic tract using interrupted sutures (Fig. 37-26). By suturing the
transversalis fascia to Cooper's ligament, the femoral canal is obliterated.
Around the internal ring, the leaflets of the transversalis fascia are sutured
to the iliopubic tract to tighten the ring. The nature of the repair therefore
specifically addresses femoral, direct, and indirect hernia defects. A mesh
prosthesis is then implanted over the posterior aspect of the transversalis
fascia and fixed to Cooper's ligament and above the iliopubic tract.
Kugel Repair
The Kugel repair aims to maximize on the preperitoneal
approach while minimizing on the length of the skin and fascia
incision.29 An oblique skin incision is made approximately 2 to 3 cm
above the internal ring, which is estimated to be halfway between the anterior
superior iliac spine and the pubic tubercle. The 3- to 4-cm incision is made one
third lateral and two thirds medial between these two structures. The abdominal
wall is opened using a series of muscle splitting incisions similar to open
appendectomy. The external oblique aponeurosis is incised, the internal oblique
muscle is bluntly divided, and the transversalis fascia is opened vertically for
3 cm, avoiding the internal ring. Blunt dissection is then performed within the
preperitoneal space, deep to the inferior epigastric vessels. Cooper's ligament,
the pubic tubercle, the iliac vessels, and the hernia sac are palpated to aid in
anatomic identification. Hernia sac dissection and division, if necessary, is
similar to other open preperitoneal approaches. Similarly, dissection along the
spermatic cord should be carried proximally enough to accommodate a mesh that
will adequately cover the internal ring. In Kugel's view, placing the patch
sufficiently posterior is the most critical part of preventing recurrences;
however, the preperitoneal pocket should be dissected only up to the point that
it barely accepts the mesh prosthesis. The pocket should extend 3 cm medial to
the pubic tubercle and lateral to the lateral extent of the transversalis
incision. The procedure is inextricably linked to a specially designed mesh. The
8 x 12 cm mesh is composed of two sheets of polypropylene, with a
slit in the anterior layer that accommodates a single digit or instrument during
mesh positioning. The mesh can be deformed to fit through the small incision,
yet the self-retaining single monofilament fiber around the periphery of the
mesh allows the mesh to spring open, assuming its normal shape. Additional
features of the mesh promote anchoring and incorporation of tissue into the
mesh. The mesh is oriented parallel to the inguinal ligament, with three fifths
sitting above the level of the inguinal ligament. The transversalis fascia is
closed with a single absorbable stitch, incorporating the anterior surface of
the mesh to prevent migration. The remainder of the wound is closed in
successive layers using absorbable sutures. Kugel's experience of nearly 1500
patients demonstrates excellent recurrence rates (0.4%); however, these have not
been reproduced owing to a steep learning curve associated with blind placement
of the patch.30
Prolene Hernia System
The Prolene hernia system technology was constructed to
take advantage of the benefits of the anterior and preperitoneal repair using an
open approach. The mesh consists of two large flaps (an onlay and an underlay
patch) with an intervening connector (Fig. 37-27). The underlay is positioned in
the preperitoneal space while the overlay rests along the floor of the inguinal
canal. Exposure of the inguinal canal is identical to standard open approaches.
The preperitoneal space is entered according to the site of the defect. Indirect
hernia sacs are dissected from the spermatic cord and sponge dissection of the
preperitoneal space is subsequently performed through the internal ring. In the
case of direct defects, the transversalis fascia is opened to provide for
preperitoneal dissection. The underlay portion of the mesh is then placed
through the hernia defect, thereby overlapping direct, indirect, and femoral
site defects. The overlay flap reinforces the inguinal floor similar to a
tension-free repair. Only the anterior layer of the mesh is secured, using three
to four interrupted sutures to the pubic tubercle, inguinal ligament, and
internal oblique muscle. As well, the overlay flap contains a slit to
accommodate the spermatic cord. The bilayer connector prevents mesh migration
and ensures correct positioning. The greatest advantage to this technique is
that it adds a preperitoneal reinforcement to an otherwise open tension-free
repair
Laparoscopic
Laparoscopic inguinal hernia repairs capitalize on the
preperitoneal approach using a series of small incisions. The predominant
techniques include transabdominal preperitoneal (TAPP) and totally
extraperitoneal (TEP) repair, with intraperitoneal only mesh (IPOM) performed
the least. The operating room setup is identical for both TAPP and TEP
procedures. Mobilization of intra-abdominal and preperitoneal contents is
optimally achieved by placing the patient in a Trendelenburg position. To this
end, the monitors are placed at the foot of the bed, allowing the surgeon and
assistant to view the procedure in a direct line of sight with instrumentation.
The surgeon generally is positioned on the contralateral side to the hernia in
question, although bilateral hernias can be repaired from either side. An
assistant will occupy a position opposite the surgeon. The patient's arms are
tucked at their sides and efforts must be made to adequately secure the patient
during mobilization to the Trendelenburg position. Before performing the
surgical prep, the bed should be tested to ensure the patient is fully secured
and can hemodynamically tolerate being in Trendelenburg during the procedure.
The scrub nurse and instrumentation table can be positioned on either side of
the bed or at the foot of the bed. Figure 37-28 demonstrates a typical operating
room setup for laparoscopic inguinal hernia.
Emergent
The indications for emergent inguinal hernia repair are
incarcerated and strangulated inguinal hernias, as well as sliding hernias. By
definition, an incarcerated hernia is one that cannot be reduced. Reasons for
incarceration include a large amount of intestinal contents within the hernia
sac, dense and chronic adhesions of hernia contents to the sac, and a small neck
of the hernia defect in relation to the sac contents. The common factor that
predisposes these aforementioned hernia syndromes to emergent operation is
compromise of intestinal contents.
An incarcerated inguinal hernia without the sequelae of a
bowel obstruction is not necessarily a surgical emergency. However, once the
patient demonstrates bowel obstruction secondary to incarceration or a sliding
inguinal hernia, operative intervention becomes expedited. Patients will often
present with vomiting, constipation, obstipation, a distended abdomen, or
combination thereof. In a sliding hernia, only one wall of a hollow viscus is
present within the hernia sac. Although the lumen of the intestine is initially
patent, strangulation of the knuckle of bowel may progress to localized edema
and subsequent obstruction of the entire lumen. Less commonly, a sliding hernia
will result from a portion of the bladder present within the hernia.
The most common presentation of small-bowel obstruction is
usually secondary to previous operation and presence of adhesions. However, in
the case of a patient with small-bowel obstruction and virgin abdomen, the
diagnosis of carcinoma and inguinal hernia incarceration should be considered
first. Physical examination is generally directed to the affected abdomen;
however, the inguinal regions must be examined to rule out the presence of an
incarcerated hernia. In the case of an ambiguous physical examination,
radiologic evaluation such as CT should be considered early to define the source
of obstruction. Failing this, diagnostic laparoscopy should be undertaken with
the dual aim of diagnosing and alleviating the source of obstruction.
For known incarcerated hernias, reduction should be
attempted before definitive surgical intervention. Hernias that are not
strangulated and do not reduce with gentle pressure should undergo taxis. The
patient is sedated and placed in a Trendelenburg position. The hernia sac is
grasped with both hands, elongated, and then milked back through the hernia
defect. Pressure applied to the most distal portion of the sac will cause the
contents to mushroom and prevent reduction. Before attempting taxis, the patient
should be made aware of potential surgery in the case of failure of the
maneuver. Laparoscopy can be considered initially in the algorithm of treatment;
however, most surgeons would prefer to approach incarcerated hernias with a
conventional open approach.
If the blood supply to incarcerated contents becomes
compromised, an incarcerated hernia becomes a strangulated hernia. These pose a
significant risk to life because the strangulated contents are ischemic and may
quickly lose viability. Clinical signs that indicate strangulation include
fever, leukocytosis, and hemodynamic instability. The hernia bulge usually is
very tender, warm, and may exhibit red discoloration. Taxis should not be
applied to strangulated hernias as a potentially gangrenous portion of bowel may
be reduced into the abdomen without being addressed. Before proceeding with
surgery, the patient should be hemodynamically resuscitated with electrolytes,
undergo nasogastric tube placement, and consideration should be given to early
prophylactic IV antibiotics. Strangulated inguinal hernias should be approached
using a conventional open technique. Once the hernia sac is encountered, efforts
must be made to control it and prevent its inadvertent reduction into the
abdominal cavity. The sac is opened to assess the viability of its contents. If
viable, the contents are reduced intra-abdominally. If viability is in question,
the hernia defect is expanded to alleviate the pressure on the intestinal
vasculature and allow the intestine to be mobilized into the operative field.
The bowel is then wrapped in warm wet towels and reassessed. Bowel viability can
be assessed by bowel color, temperature, presence of peristalsis, and the Woods
fluorescein test. Entrapped bowel within a femoral hernia may necessitate
division of the inguinal ligament to provide for reduction and mobilization of
the bowel. If the bowel is clearly ischemic and nonrecoverable, a decision must
be made to resect the affected intestinal portion using the groin incision or
perform a lower midline incision to increase exposure. Ideally, the ischemic
portion is resected and viable portions are anastomosed to restore intestinal
continuity. If the procedure becomes clean-contaminated through the resection of
bowel, or if the intestine has been significantly compromised, repair of the
hernia should proceed without the use of prosthetics, for fear of contamination
and infection of the mesh.
Not uncommonly, an incarcerated or strangulated inguinal
hernia may reduce with the administration of general anesthesia. A suspected
strangulated hernia sac that reduces inadvertently during anesthesia induction,
or before visual inspection by the surgeon, usually necessitates the conversion
of the procedure to a laparotomy or laparoscopy to fully assess the bowel for
viability. The consequences of a retained portion of ischemic bowel may lead to
dire consequences for the patient's life.
Rarely, a surgeon will discover that upon entering the
inguinal canal during emergent hernia treatment that no inguinal hernia exists.
In these situations, strong consideration should be given to the presence of a
femoral hernia. The femoral canal, located inferior to the medial inguinal
ligament, is assessed for presence of an incarcerated or strangulated
hernia.
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