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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_961_Библиотеки_им_академика_М_И_Перельмана.pdf
Principles in Hernia Surgery
David H. Bennett
6
Abdominal wall hernia surgery is no different from any
other surgical procedure in that the rules of appropriate
patient selection and preparation apply. The mortality from
hernia surgery relates either to operating prior to optimization of the patient or to complications of the surgery itself.
An analysis of the Scottish Audit of Surgical Mortality
noted inadequate resuscitation, failure to use HDU, and
inadequate perioperative monitoring as adverse factors contributing to death [ 1 ] . Most hernias never require emergency
surgery, and 4 or 5 h of careful resuscitation may be
bene fi cial in the most ill patients [ 2 ] . Analysis of the Swedish
Hernia registry revealed a sevenfold increase if the surgery
was performed as an emergency and a 20-fold increase if
bowel resection was undertaken [ 3 ] . The same principles
apply for elective hernia surgery: -full assessment and optimization of the patient prior to embarking on surgery.
An analysis of 175 patients with ages greater than 66 years,
of whom 58% were ASA III or higher, revealed that elective
or urgent operation can be carried out with zero mortality,
provided prompt diagnosis and management of primary systemic diseases are performed.
Careful consideration should be given to the type of anesthesia employed with general, regional, or local anesthesia all
available. However, it should be remembered that in some
cases, general anesthesia may be safer than epidural anesthesia. Severe systemic disease that limits activity but is not incapacitating is not a contraindication for elective groin repair.
General Principles
There are three principles which dictate the management of
abdominal wall hernias:
D. H. Bennett (*)
Department of Surgery , Royal Bournemouth Hospital ,
Dorset , United Kingdom
e-mail: david.bennett@rbch.nhs.uk
1. Identi fi cation of the hernia sac and dissection of the sac
neck. It is important to identify the sac neck as this de fi nes
the fascial edges which will form the basis of subsequent
repair. In large incisional hernias the neck may be many
centimeters distant from the apparent extent of the sac
itself.
2. Reduction of the contents. For elective inguinal hernia
surgery, indirect sacs are often reduced at the time of
operation, and there is no necessity to open the sac. For
incarcerated or strangulated hernias, the sac should be
opened, and the contents inspected for viability prior to
reduction. In the case of large sacs containing large
amounts of bowel and/or organs, the possibility of loss of
domain should be considered. The forcible reduction of
sac contents into an abdominal cavity which has lost
capacity can result in the development of abdominal compartment syndrome. In the case of large incisional hernias, following opening of the sac, there may be a
signi fi cant amount of redundant sac which must be excised
prior to the repair.
3. Repair of the fascial defect. Over the last 10 years, the
concept of “tension-free repair” has become established,
and one of the commonest causes of recurrence post repair
is excessive tension on the fascial edges. In parallel with
this philosophy has been the development of prosthetic
material to aid this approach. The primary goal of repair
is therefore to achieve apposition of the fascial edges with
reinforcement of the muscle layers with prosthetic material, if appropriate.
It should be noted that only tendinous/aponeurotic/fascial
structures can be successfully sutured together; suturing
fl eshy muscle to tendon or fascia does not provide a permanent union of these structures nor does it restore normal
anatomy. The development of prosthetic reinforcement has
led to a new range of procedures for hernia repair including
the laparoscopic approach. The use of prosthetic material in
the repair of hernias of all etiologies is now commonplace,
its use exceeding 90% in the USA.
A.N. Kingsnorth and K.A. LeBlanc (eds.), Management of Abdominal Hernias,
DOI 10.1007/978-1-84882-877-3_6, © Springer Science+Business Media London 2013
91
92 D.H. Bennett
Hemostasis
Although hernia surgery is sometimes considered to be
“minor surgery,” the principles of careful hemostasis and tissue handling are just as important as in any other operation if
hematoma formation and sepsis are to be avoided. There are
signi fi cant vessels in the subcutaneous fat, especially veins,
which are prone to bleed and should either be appropriately
controlled with electrocautery or the time taken to ligate
them with an absorbable suture. For ligatures, metric 3.5
(3/0)-braided polyglycolic acid (Dexon) or metric 3.5
(3/0)-braided polyglactin (vicryl) is recommended.
If local anesthesia with adrenaline is used, extra care with
hemostasis is advised as hematomas are more likely. If the
dissection is extensive or there is a large “dead space” in which
hematoma or serum can collect, a closed suction drain can be
used. During the open repair of large incisional hernias, suction drains are frequently employed, both in the retromuscular
plane to reduce seroma formation if a prosthetic mesh has
been used and in the subcutaneous residual cavity left following reduction of a large hernia sac. Suction drains are rarely
used when a hernia has been repaired laparoscopically.
Sepsis
is not removed until the wound is closed. This is particularly
popular during laparoscopic incisional hernia repair.
It had been recommended in the past that sutures should
not be used to close the skin, for by their very nature they
have the potential to introduce bacteria into the subcutaneous
tissue along their tracks [
many methods are used to close the skin incision. These
include the use of skin staples, subcuticular sutures, skin closure tapes, and skin adhesives. There is no evidence that any
one technique is signi fi cantly superior to the others such that
a recommendation can be made. It falls upon each surgeon to
maintain vigilance of his or her practice and base the skin
closure upon the best results that are obtainable.
The rates of infection following laparoscopic hernia repair
are compatible with those of open inguinal hernia repair,
which is of the order of 1% [
hernia repair is an important complication as it increases the
risk of hernia recurrence by a factor of four [ 8, 9 ] . If an infec-
tion develops following a laparoscopic incisional hernia
repair, in the majority of cases the prosthetic material will
need to be removed, resulting in the original fascial defect
requiring repair again. An open primary suture technique
may be employed with or without reinforcement with a biological (fully absorbable) mesh.
6 ] . However, current practice reveals
7 ] . Infection following inguinal
The presence of infection in hernias can be divided into
super fi cial and deep sepsis. When present, deep sepsis in the
presence of a synthetic prosthetic mesh is a signi fi cant complication which may require the explant of the prosthesis.
The prophylactic use of antibiotics has not been shown to
reduce the risk of either super fi cial or deep infection in inguinal hernia repair. In a Cochrane review totaling almost 9,000
patients, the incidence of infection was 3.9% and 4.5% in the
prophylaxis and control groups, respectively [ 4 ] . Analysis of
the Swedish hernia registry revealed just over 20% of patients
undergoing elective inguinal hernia surgery received prophylactic antibiotics. The European Hernia Society published
recommendations on the use of antibiotics in inguinal hernia
surgery in 2008 [ 5 ] . It was noted that, in clinical settings with
low rates (5%) of wound infection, there is no indication for
the routine use of antibiotic prophylaxis in elective open
groin hernia repair in low-risk patients. The consensus group
also concluded that in endoscopic hernia repair, antibiotic
prophylaxis is probably not indicated. Finally, it was concluded that in the presence of risk factors for wound infection based on patient (recurrence, advanced age,
immunosuppressive conditions) or surgical (expected long
operating times, use of drains) factors, the use of antibiotic
prophylaxis should be considered. As with all surgical procedures, one must nevertheless utilize scrupulous surgical
technique if infection is to be avoided. The skin may be covered at the site of operation with sterile adherent fi lm, which
Wound Healing
Important variables in hernia repair are the rate at which the
aponeurosis regains strength and the stability of the healing
process. This is becoming more important as the newer
meshes are incorporating a component which is absorbable
over time and relies on the increase in wound strength with
time to compensate for the absorption of the synthetic material. Many of the factors that regulate wound healing are
under the control of the surgeon, and an appreciation of their
effects and their clinical signi fi cance is important in the care
of the patient and the type of prosthetic reinforcement
selected.
The pioneering work on the maturation and development
of tensile strength in wounds was reported by Howes and his
group in 1933. They reported the healing of experimental
skin, fascia, muscle, and gastric wounds in dogs. They
observed a lag phase extending from wounding until the 5th
or 6th day. During the lag phase, the wound appeared quiescent, the wound strength did not increase, and wound apposition was maintained by the sutures only (Fig. 6.1 ) [ 10, 11 ] .
This was followed by a phase of fi broplasia, during which
wound strength increased rapidly, reaching a maximum
around the 14th to 16th day.
Howes also went on to describe a third phase—the maturation phase—which he did not study, attributing restoration
of the mechanical strength to the fi broblastic phase. However,
936 Principles in Hernia Surgery
Fig. 6.1 Phases of wound healing. During the initial lag phase the
wound is quiescent and during the fi broplastic phase wound strength
increases rapidly over a few days; however, it is in the third, maturation,
phase that signi fi cant and permanent strength gain occurs
we now know that this third phase is crucial to the healing of
aponeurotic wounds.
Douglas (1952) studied the rate of tensile strength gain of
incisions in the lumbodorsal aponeurosis of rabbits. He demonstrated that the rate of increase of tensile strength was
slow, 50% of the original strength was gained at 50 days, and
only 80% achieved after 1 year [ 12, 13 ] . Similarly, Mason
and Allen (1941) had observed healing tendons. They noted
that if the tendon was rested, the rate of gain of strength during the maturation phase was slower than if active motion
was permitted [ 14 ] , an observation supporting early ambula-
tion after hernia surgery.
In humans, the lag (or latent) phase extends from the time
of incision to the fourth to sixth day. During this phase the
in fl ammatory reaction prepares the wound for subsequent
healing by removing debris, necrotic tissue, and bacteria. At
the same time there is mobilization and migration of fi broblasts
and epithelial cells and accumulation of non-collagenous
proteins and glycoproteins. During the lag phase, fi brin alone
holds the wound edges together, and wound security is a
property of the suture material not the tissue. Similarly, the
initial cellular penetration of any prosthetic material occurs at
this time.
At about day 4–6 post incision, proliferating fi broblasts
begin to synthesize collagen, mucopolysaccharides, and glycoproteins, the fi broblastic stage of repair. The collagen
quickly aggregates into fi bers commensurate with the most
rapid increase in the tensile strength of the wound. It is at this
stage that incorporation of the prosthetic meterial into the tissues occurs. The meshes with the largest pores (macroporous)
experience a greater degree of collagen deposition during this
time interval than the microporous meshes. Prior to this stage,
even the microporous interstices are fi lled with fl uid rather
than cells. The newer microporous meshes are manufactured
into such a form that the fi broblasts and macrophages appear
earlier in the healing phase, thereby providing greater collagen and tissue attachment earlier [ 15 ] .
As the fi brotic phase runs down, the phase of maturation
begins. During this phase, further wound strength gain is due
to intra- and intermolecular collagen remodeling and crosslinking. This remodeling continues for 6–12 months, and it
has been postulated that failure of this remodeling process
may account for the late appearance of incisional hernias in
healed laparotomy incisions [ 16– 18 ] .
The principles of wound healing remain the same regardless of whether the incision is for a primary laparotomy, a
primary hernia, or an incisional hernia. Incised fascial and
aponeurotic edges heal faster and are ultimately stronger
than invaginated or infolded aponeurotic or fascial wounds.
This is because incision of tissues initiates the normal cascade of healing mechanisms, which ultimately leads to formation of organized collagen and mature strong connective
tissue. Invagination causes disorganized healing and defects
in collagen formation which can become apparent as areas of
weakness with potential for recurrence. Similarly, interrupted suture closure causes areas of local ischemia and
uneven distribution of tension along the incision, resulting in
the multiple small incisional hernias sometimes seen occurring through the suture holes. Aponeuroses have only weak
powers of regeneration, the abdominal wall taking up to 120
days before it reaches 80% or more of its original strength
[ 19 ] . In principle, continuous suturing of aponeurosis and
fascial planes by evenly distributing the tension gives better
ultimate healing than interrupted suture closure.
It is likely that a connective tissue abnormality underlies
the majority of hernia occurrences and, over the last 15 years,
reinforcement of the native abdominal wall with prosthetic
material has been employed to prevent hernia recurrence
[ 20 ] . The normal process of wound healing in the presence
of a prosthetic material involves coagulation, in fl ammation,
angiogenesis, and epithelialization. This is then followed by
fi broplasia, matrix deposition, and, fi nally, scar contraction.
The cellular components involved in this process are initially
platelets followed by monocytes, macrophages, leukocytes,
fi broblasts, endothelial cells, and smooth muscle cells.
A variety of growth factors and cytokines are activated which
coordinate the process [ 21 ] . The prosthetic material subse-
quently undergoes maturation with the scar contraction that
occurs in all wounds and accounts for the shrinkage of
meshes. If an explanted mesh is placed in a collagenase solution and the scar tissue dissolved from the mesh interstices,
the mesh returns to its original size.
The rate of wound healing and the ultimate tensile strength
of wounds are adversely affected by severe protein de fi ciency,
vitamin C de fi ciency, prolonged hypovolemia, increased
blood viscosity, intravascular coagulation, cold vasoconstriction, and chronic stress. Hypoxia, some drugs, irradiation,
94 D.H. Bennett
Fig. 6.2 Relationship of wound strength gain to the rate of wound
healing in aponeurotic wounds. Absorbable sutures do not survive long
enough to ensure wound stability. Polydioxanone occupies an intermediate position between the traditional catgut and the absorbable polymers on the one hand and the nonabsorbables on the other
and other factors can be critical in wound healing. For the
surgeon, the most important variables are suture strength to
maintain wound apposition until collagen synthesis is well
advanced and exercise of the healing incision which speeds
the entire process [ 14, 22– 24 ] .
Currently, the rate of wound healing has become less of a
factor due to the introduction of prosthetic meshes and
modern suture materials (in open repairs) or fi xation devices
(in laparoscopic repairs). Surgeons who routinely employ
prosthetic implants for their hernia procedures do not wait
for the maturation phase of wound healing to be completed
before encouraging patients to resume normal activities.
Most patients would be expected to have returned to normal
daily activities 2–3 weeks after elective open or laparoscopic
inguinal hernia surgery.
Sutures
“The material used for sutures is probably not very important” observed Aird, in 1957 (Fig.
50 years since this quote and during this time the dynamics
of wound healing has been de fi ned and a revolution has overtaken sutures [
26 ] and methods of hernia surgery. With regard
to sutures, the current surgeon chooses a suture according to
objective biological data and marries biological science to
surgical craft. Naturally occurring sutures—silk, linen, and
catgut—are obsolete in hernia surgery; synthetic fi bers are
today’s choice [ 27 ] .
In the past, the choice of suture material was based on
availability and experience and, indeed, until recently surgeons have concentrated on the mechanical properties of the
suture with scant attention to the interaction of the suture and
host tissue. Three principles should be taken into account
when considering the mechanical and biological relations of
suture and tissue [
28 ] .
6.2 ) [ 25 ] . It is more than
1. Sutures should be at least as strong as the normal tissue
through which they are placed.
2. If the tissue reduces suture strength with time, the relative
rates at which the suture loses strength and the wound
gains strength are important.
3. If the suture alters the biology of wound healing, the
impact of this alteration is important.
Applying these principles to wound healing, the surgeon
requires information about the normal strength of the tissue,
the rate of gain of strength of the wounded tissue, the
strength of the suture, the rate at which the suture loses
strength when placed in tissue, and the interaction of suture
and tissue. Only after considering these factors can the surgeon proceed to account for the handling and knotting properties, the “memory,” ease of sterilization, and shelf life of
the suture.
Sir Berkeley Moynihan, at the inaugural meeting of the
Association of Surgeons in 1920, set out the essential conditions for sutures and ligatures which must remain within the
wound [
29 ] . Such material should ideally (a) achieve its
purpose,—be suf fi cient to hold parts together, close a vessel,
etc.; (b) disappear as soon as its work is accomplished; (c) be
free from infection; and (d) nonirritant. These principles are
still important today.
Sutures are either absorbable or nonabsorbable and are
made from natural or synthetic products, distinctions that are
increasingly blurred by modern polymer chemistry.
Tissues that are mainly formed of collagen/fascia/
aponeurosis tend to heal slowly, so that only 50% of their
original tensile strength has been recovered at 3 months;
thus most older absorbable sutures, whether natural or
synthetic, do not generally persist long enough for the adequate structural integrity to be restored. However, the healing curve of these tissues, a curve that re fl ects the laying
down of collagen, is initially steep, so that fascia or
aponeurotic incisions of the abdominal wall closed with
absorbable sutures or, more particularly, the modern synthetics may just have enough strength to withstand disruption unless there are major forces, such as coughing applied
to them. In contrast, tissues which do not contain much
structural collagen heal and gain their initial tensile
strength much more rapidly, the intestine being a particular example of this [ 30 ] .
The suture material must retain its strength for long
enough to maintain tissue apposition and allow sound union
of tissues to occur. In aponeurotic wounds, a nonabsorbable
or very slowly absorbable suture material must therefore be
employed. The inherent disadvantageous properties of nonabsorbable suture materials—proneness to sepsis, adverse
tissue reaction, and sinus formation—have led some surgeons to seek compromises for hernia repair.
Table 6.1 lists the properties of natural and synthetic
suture material.
Table 6.1 Sutures (in the sizes available for hernia surgery)
Suture Raw material Type In vivo tensile strength retention Trade name
Plain Sheep submucosa Absorbable 67% lost in 5–6 days
Chromic Sheep submucosa Absorbable 67% lost in 10–14 days
Poliglecaprone 25 Copolymer of glycolide and
E-caprolactone
Polyglycolic acid Polyglycolic acid Absorbable Dexon
Polyglactin 910 Copolymer of lactide and
glycolide
Polyglactin 910 coated
with polyglactin 370
Polydioxanone Polyester of poly (p-dioxanone) Absorbable 50% lost in 28 days PDSII
Silk Silkworm larvae Nonabsorbable Lost in 1 year Panacryl
Nylon Polyamide polymer Nonabsorbable 15–20% per year is lost Ethilon
Stainless steel Stainless steel Nonabsorbable Fatigue fractures at 1 year
Braided Nylon Polyamide polymer Nonabsorbable 15–20% per year is lost Nurolon
Polypropylene Polymer of propylene Nonabsorbable Two years or longer P rolene
Polyester Polyethylene terephthalate Nonabsorbable Lasts inde fi nitely Mersilene
Coated polyester Polyethylene terephthalate
Expanded polytetra fl uoroethylene
Copolymer of lactide and
glycolide coated with same
combined with calcium stearate
coated with polybutilate
Polytetra fl uoroethylene Nonabsorbable Lasts inde fi nitely Gore-tex
Absorbable 70–80% lost in 14 days Monocryl
Absorbable 60% lost in 21 days Vicryl
Absorbable 60% lost in 21 days Coated Vicryl
Nonabsorbable Lasts inde fi nitely Ethibond
®
®
®
®
®
®
®
®
®
®
®
extra
956 Principles in Hernia Surgery
®
Synthetic Absorbable Sutures
The fi rst polymer possessing reasonable physical and biological properties was synthesized in the 1960s by Du Pont
Research Laboratories. It was a braided polyester suture
made of poly- l -lactide. The fi rst commercially available
absorbable synthetic suture was also a braided polyester,
polyglycolic acid (PGA, Dexon), introduced in 1971.
In 1974 another braided polyester suture polyglactin 910
(Vicryl), a copolymer of lactide and glycolide, was intro-
31 ] .
duced [
The basic ingredients of these polymers and their eventual
breakdown products are lactic acid, glycolic acid, or a combination of the two. Compared with catgut and collagen,
these biodegradable polymer sutures have some interesting
properties. Catgut and collagen are digested by cellular
enzymes and, therefore, excite an intense cellular reaction,
which prolongs the lag phase in wound healing. The new
polyester sutures degrade by hydrolysis and do not excite
cellular activity; indeed they will hydrolyze similarly in vitro
if placed in buffer solution at body temperature. Consequently
they do not delay wound healing. They are also much more
uniform and predictable in their dimensions and tensile
strength than the biologically made natural fi bers formerly
used because they are synthetic materials produced under
tight manufacturing control.
The polymer sutures however do have disadvantages.
While they possess greater and more predictable strength
than catgut and collagen, they are also much harsher and
stiffer fi bers. These sutures have to be braided to provide
good handling characteristics and carefully tied to avoid slippage on the fi rst throw when tied. Their stiffness means only
extremely fi ne mono fi laments can be used in surgery, their
usefulness con fi ned to microsurgery and ophthalmology.
In order to overcome the abrasive quality of these fi bers
and to improve tying, coated polymer sutures have been
introduced. The coating decreases the “drag” through tissues
and allows sliding of knots for better control.
Polydioxanone (PDS) is a newer more fl exible polyester
suture, introduced in 1981. Its greater fl exibility, compared
with PGA and polyglactin 910, allows it to be used as a
mono fi lament. Like all polyesters it degrades by hydrolysis
and excites little tissue reaction; however, its rate of degradation is much slower than that of PGA or polyglactin 910.
Polydioxanone suture was completely absorbed from rat
muscle by 180 days versus 60–90 days for polyglactin 910
and 120 days for PGA suture. In vivo polydioxanone retains
its strength for longer than other synthetic absorbable
sutures: 58% versus 1–5% at 4 weeks and 14% versus 0% at
8 weeks [
32, 33 ] .
The place of synthetic absorbable sutures in hernioplasty
is unclear. There were early favorable reports of the use of
96 D.H. Bennett
PGA sutures (Dexon) for laparotomy closure. Irvine et al.
(1976) [
in a randomized clinical trial and reached the conclusion that
there was little to choose between these sutures. The trial
was small: 161 cases randomized equally to each suture, a
layered closure used—the wound failure rate was 5.8% for
polyglactin, 9.6% for PGA, and 8.8% for polypropylene.
Wound failure rate was closely related to wound infection
[ 34 ] . When PGA was compared with nylon mass closure
rate, the rate of wound failure was 12.5% in the PGA group,
compared with 4.7% in the nylon group. It was concluded
that closure of abdominal wounds with absorbable sutures
does not appear to be justi fi ed [ 35 ] . Polyglactin and particu-
larly polydioxanone sutures have prolonged tissue integrity
compared with PGA and may therefore be more satisfactory
for laparotomy closure—indeed, polydioxanone has been
shown to be comparable to a nonabsorbable suture [
Current practice would suggest most laparotomy incisions
are primarily closed with nylon or polydioxanone. In the
case of prosthetic mesh fi xation in open inguinal hernia surgery, a longer-lasting absorbable suture, particularly polyglactin or a mono fi lament such as prolene, is utilized. In the
case of laparoscopic inguinal hernia surgery, the initial
method of fi xation was nonabsorbable metal tacks. However,
this practice has been superseded by the use of absorbable
tacks, fi brin glue, or, indeed, no fi xation at all.
34 ] compared PGA, polyglactin, and polypropylene
36 ] .
Nonabsorbable Sutures
For closure of aponeurosis/fascial planes, a nonabsorbable
mono fi lament fl exible material with good knotting properties has been considered the gold standard. Stainless steel
wire provides the greatest strength and knot security and is
routinely used in sternotomy closure. However, the poor
handling characteristics of wire limit its usefulness in hernia
surgery, despite its additional advantage of minimal tissue
reaction. For many years, silk was the standard nonabsorbable suture material and has enjoyed the widest use. Silk was
recommended by Halsted and by Whipple [ 35, 37 ] .
In terms of strength and knot security however, silk is distinctly inferior to many other materials, and the tissue reaction to silk correlates to the incidence of granuloma and
sinuses in clinical use. Cotton was introduced in 1940 during
World War II when silk was relatively unobtainable. Its
strength is similar to silk, but its handling characteristics are
inferior—again it has a high incidence of granuloma and
sinus formation. Linen is similar to cotton in many
properties.
Nylon was developed by the Du Pont Company and
introduced as an alternative to silk in 1943. Compared with
silk, nylon has distinct advantages: it can be used as a
mono fi lament, it loses less strength when wet (15% versus
25%), it is stronger, and it causes less tissue reaction. However,
it is not as fl exible, it is more dif fi cult to handle and to knot,
and the knots have a tendency to slip. Mono fi lament nylon
undergoes both plastic (irreversible) and elastic (reversible)
elongation when subjected to tension. When nylon is
stretched using a force of 5 kg, the total elongation produced
is 22.5%, of which 6.9% is irreversible. When aponeurotic
incisions are closed with nylon and then the sutures are tightened to 5 kg to produce “compression” of the wound, the
suture stretches by 27.7% [ 38 ] . This plastic irreversible elon-
gation has an importance in closing fascial incisions: unless
the nylon is tightened adequately, its elongation when the
patient breathes and moves will lead to loss of apposition of
the wound edges and ultimately to wound failure.
Mono fi lament polypropylene is an alternative to nylon.
It has greater fl exibility and easier handling characteristics.
It also knots better than nylon [
acteristic does, however, make this material dif fi cult to use in
certain circumstances.
Braided nonabsorbable sutures have distinctly better handling and knotting characteristics than mono fi laments, but
they give the least good results for suturing aponeurosis and
repairing hernias. The speci fi c problems are infection, and
the persistent sinuses that develop and so braids should be
abandoned. If infection occurs in a wound repaired with a
nonabsorbable braid, there is no alternative to removing he
suture. With mono fi laments, infection can be controlled and
suture removal is not always required. Others have con fi rmed
the unsuitability of braided nonabsorbable sutures in hernia
repair [
41 ] .
39, 40 ] . The “memory” char-
Mechanical Factors in Abdominal Wound Closure
Wounds are not set in their dimensions but undergo change
as they heal. Not only do the wounds themselves change but
the cavities or tissues they contain alter, and these alterations
critically vary the dimensions of the wound.
The events of wound healing lead to edema of the wound
and then to the development of a healing ridge and fi broblast
proliferation as collagen placement gets under way. Edema of
the wound by increasing wound bulk increases the tension in
each suture bite. If suture bites are initially tight, this increase
in tension may lead to (a) suture breakage, (b) knot failure, or
(c) cutting out. These three consequences may also develop
from changes in body compartments beneath suture lines. In
the abdomen, extreme examples of this phenomenon occur.
In voluntary inspiration, pregnancy, and abdominal distension, mean alterations of girth of 6%, 18%, and 27% have
been measured, while simultaneously the mean xiphoid to
pubis distance increases by 12%, 15%, and 37%, respectively
(Table 6.2 ). In these circumstances an abdominal wound will
increase in length by an estimated 30% overall.
976 Principles in Hernia Surgery
Table 6.2 Increases in girth and xiphoid–pubis distance caused by
abdominal distension (from Jenkins 1976, with permission)
Percentage increase in distension
Abdominal distension
associated with:
Voluntary inspiration ( n −18)
Cesarean section ( n −27)
Gut obstruction or paralytic
ileus ( n −5)
Type of
measurement
Girth
Xiphoid–pubis
Girth
Xiphoid–pubis
Girth
Xiphoid–pubis
Mean
value
6
12
18
15
27
37
Extreme
value
11
18
94
36
53
67
The alterations in wound length that occur during healing
have a critical impact on the technique of suturing an abdominal wound. Jenkins has analyzed this geometrically [ 42 ] and
concluded that the ratio of suture length (SL) to wound length
(WL) is critical aponeurosis repair.
An SL:WL ratio of 4:1 is optimum; if the SL:WL ratio
decreases below 2.5:1, the risk of wound disruption
increases geometrically. Wound disruption is inevitable as
the SL:WL ratio approaches 1:1. This mathematical analysis (Jenkins’ rule) is con fi rmed when tested in clinical practice. These fi ndings have been corroborated by Israelsson
30 years later [ 43, 44 ] . In two studies examining cohorts of
over a 1,000 patients from 1989–1991 to 1991–1993,
respectively, Israelsson showed that a suture length to
wound length of less than 4 was the greatest risk factor for
wound failure and predictor of later incisional hernia with
lesser risks associated with age, obesity, and wound infection. The surgeon was also an important risk factor in that
incisional hernia rates varied from 5 to 26% between individuals. Interestingly in overweight patients (BMI > 25),
there was no increase in wound infection rate if the suture
length to wound length was between 4.0 and 4.9 although
incisional hernias developed in these patients in 15% of
cases after 12 months.
Surgical practice, however, continues to rely largely on
tradition rather than high-quality level 1 evidence when
choosing the ideal method of abdominal fascial closure [ 45 ] .
Hodgson and colleagues carried out a systemic review and
meta-analysis to determine which suture material and which
technique reduces the odds of incisional hernia. They studied
only randomized controlled trials with a Jadad quality score
of >3 (Jadad Quality Scale is the only validated instrument
available to assess the quality of randomized control trials.)
There were two independent reviewers masked to the study
site, authors, journal, and date. The results showed:
1. There was a low occurrence of incisional hernia with non-
absorbable sutures.
2. Suture technique favored nonabsorbable, continuous
suturing.
3. Sinus tract formation and wound pain were lower with
absorbable sutures.
4. There was no difference in dehiscence rates or wound
infection rates with respect to method of closure or material used.
Abdominal fascial closure with a continuous nonabsorb-
able suture had a signi fi cantly lower rate of incisional hernia.
The ideal suturing technique is continuous. The data for this
study drew information from 13 randomized trials including
a total of 5,145 patients and utilizing nine different suture
materials with a continuous or an interrupted technique,
mostly in vertical midline incisions. This meta-analysis provides the most powerful evidence yet for informing surgeons
on the optimal technique for abdominal fascial closure.
Over the last decade, there has been a signi fi cant expan-
sion in the number of techniques described to repair hernias,
and it is beyond the scope of this chapter to describe each
one in turn. The pure tissue hernia repair is rapidly becoming
outdated and currently probably only applies to small (<2 cm
diameter) primary umbilical and paraumbilical hernias. The
European Hernia Society (EHS) issued a recommendation in
2008 that all male adult (<30 years) patients with a symptomatic inguinal hernia should be operated on using a mesh
technique. The open Lichtenstein and endoscopic inguinal
hernia techniques were recommended as the best evidencebased options for the repair of a primary unilateral hernia.
If a non-mesh repair was to be used, the Shouldice technique
was recommended. For the repair of recurrent hernias after
conventional open repair, endoscopic inguinal hernia techniques were recommended [ 5 ] .
However, the situation for anterior abdominal wall her-
nias is not so clear cut. It should be noted that the surgical
literature has become very dif fi cult to interpret during this
time due to the lack of consistency in the terms used to
describe anterior abdominal wall defects. In an attempt to
make comparisons possible, the EHS held a consensus
meeting in 2008. While a de fi nitive EHS classi fi cation of
incisional hernias was not realized, a classi fi cation for primary abdominal wall hernias and a division of subgroups
of incisional abdominal wall hernias were formulated. This
classi fi cation should provide enough information to establish incisional hernia registries and may be used to compare studies on treatment and outcome of incisional hernia
repair [ 46 ] .
Certain principles should be adhered to when implanting
any prosthetic mesh. It is important to provide secure fi xation
of the prosthesis so that it does not move and to ensure there
will be no or minimal deformation of the mesh during the
healing process. Synthetic mesh should not be placed in an
infected fi eld as the mesh will act as a foreign body and
chronic sepsis will ensue, often requiring explantation of the
mesh. Newer “biological” meshes are being developed which
are completely absorbed, and these can be utilized in an
infected fi eld, often in combination with wound management
systems such as negative pressure dressings.
98 D.H. Bennett
Knots
The knot is the weakest part of a suture and knot ef fi ciency is
a crucial component of the suture technique. Conventional
knots cause a 40% decrease in the strength of most suture
materials except for nylon (and probably polypropylene).
Self-locking knots permit the end of a continuous suture to
slide inside the knot, thus absorbing some of the energy
which would otherwise be transmitted to the knot and cause
it to break [ 47 ] . Additionally, self-locking knots are less
bulky than conventional knots, thus diminishing the risk of
infection and sinus formation [ 48, 49 ] . To avoid a traditional
knot at the commencement of a wound closure, loop sutures
have been developed, the needle simply being passed through
the loop to anchor the initial stitch. A suture with miniature
barbs along its length has also been developed which does
not need to be knotted at all.
Suture Manipulation
Generally, little thought is given to the handling of the suture
material during its use and implantation into the tissues.
Most of the modern synthetics can tolerate considerable
manipulation as they are placed. One should be cognizant of
the fact that some of these materials can be frayed and weakened when they are secured in the jaws of a needle holder,
forceps, or hemostat. Sometimes the surgeon does not recognize this newly created weakness. This can result in an early
fracture of the suture material which, in effect, results in a
cut suture that is no longer intact. This can result in failure of
healing of the tissues that are held with that suture. Similarly,
this can result in a hernia recurrence if that suture is the
method of fi xation of a prosthetic material. Therefore it is
incumbent upon the surgeon to be careful in handling any
portion of a suture that will remain within the tissues so that
this will not become a problem that is manifest by a new or
recurrent hernia.
Skin Closure
Sutures, penetrating the skin and then tied on the surface,
have been the traditional closure method for wounds.
Alternatives include subcuticular sutures; skin clips, which
do not penetrate the full skin thickness; plastic tape adherent
to the skin; and fi brin glue.
The requirements for adequate skin closure are that the
skin should be held together in apposition for suf fi cient time
to allow the skin to grow together. To promote rapid healing,
the edges should not move in relation to each other and tension should be minimal to prevent necrosis. Careful suturing
should prevent the introduction of sepsis. Lastly, but perhaps
of overriding importance to the patient, a good cosmetic
result is needed.
Clean or contaminated surgery demands different regimens for wound management. One of the oldest surgical
principles is that a frankly contaminated wound should be
left open. The wound which is expected to be compromised
by early (reactionary) hemorrhage is managed by delayed
primary suture. If localized infection is anticipated, interrupted sutures may allow early controlled drainage. These
have been the traditions of wound care. Elective hernia operations nowadays are clean operations—we are searching for
quick uncomplicated healing with the best functional and
cosmetic results. Hence we should review our methods of
skin closure and optimize skin healing as far as possible.
Conventional skin suturing techniques do have certain
disadvantages—the needle passing through the skin on either
side carries fragments of both epidermis and skin organisms
down its track and into the depths of the subcutaneous tissue.
This causes an increased wound infection rate than when
skin closed by a sutureless technique is used. The complications of suture track infection are greater when a multistrand
suture is used and when the tension upon the wound edges is
too great. Poor technique in inserting the sutures and subsequent edema after suturing lead to localized ischemia and a
poor cosmetic result.
Clips avoid the problem of introducing deep infection into
the wound. Michel-type clips may produce localized tension
and cause local pressure necrosis. Unless they are removed
within 24–48 h, this local ischemia can cause tissue necrosis
and a permanently poor cosmetic result. Consequently, these
are seldom used in modern surgical theaters. Currently available disposable applicators for the introduction of wire clips
with a rectangular con fi guration of the closed clip give excellent results although the skin puncture sites may detract from
the overall cosmetic appearance. Closure with adherent skin
tape gives excellent healing [ 50– 52 ] .
A randomized controlled clinical trial comparing skin
closure using vertical mattress sutures of mono fi lament
nylon and steel clips in laparotomy incisions has con fi rmed
the signi fi cant advantage of avoiding skin sutures. In a consecutive series of 341 wounds (182 skin sutured and 159
closed with clips), the infection rate in the sutured wounds
was 17% versus 6.3% in those closed with clips ( P < 0.01)
[ 53 ] . Subcuticular absorbable sutures are probably the most
favored with surgeons, nurses, and patients. In a randomized
control trial, four different methods of thigh incision closure
after removal of the saphenous vein for coronary artery
bypass grafting were used [ 6 ] . Continuous nylon vertical
mattress sutures, continuous subcuticular absorbable PGA
sutures, metal skin clips, and adhesive sutureless closure
(Opsite) were compared. Assessment of the healing showed
subcuticular PGA to be more effective than skin clips or vertical mattress nylon sutures. The fi nal cosmetic result showed
996 Principles in Hernia Surgery
Fig. 6.3 Prosthetic repairs of abdominal wall defects. The prosthesis
can be placed extraparietally or subcutaneously ( a ); subaponeurotically,
extraperitoneally, or preperitoneally leaving any aponeurotic defect
subcuticular PGA to be superior to mattress sutures or skin
clips and as effective as sutureless adherent closure.
Subcuticular absorbable sutures do not require removal; this
is an economic saving [
54 ] . Subcuticular skin closure for
open inguinal hernia repair using polydioxanone or polyglactin 910 is recommended. The result with these sutures is
excellent, and no suture removal is required. Wound healing
is quick and neat and, most importantly, the lack of throughskin sutures has removed much of the postoperative pain and
reduced infection rates to 2–3%. Closure of laparoscopic trocar sites may be performed with subcuticular polyglactin
910, polydioxanone, fi brin glue, and/or skin tapes.
Techniques of Placement of Prosthetic Materials
There are a number of open techniques which have been
described to repair abdominal wall defects with prosthetic
mesh, the variation in the technique relating to the anatomical
open super fi cial to the prosthesis ( b ); subaponeurotically with closure
of the defect ( c ); or intraperitoneally ( d )
plane in which the mesh is placed [ 55– 58 ] : (a) extra-
aponeurotic—subcutaneous (on-lay technique); (b) and
(c) subaponeurotic and extraperitoneal or preperitoneal
(sublay technique); and (d) subaponeurotic and intraperitoneal (Fig. 6.3 ). Additionally, intraperitoneal (or sub-
aponeurotic) placement of the mesh can be supported by
an extra-aponeurotic buttress (Fig. 6.4 ). It should be
remembered that the use of mesh in open hernia surgery is
an adjunct to the application of fi rst principles, i.e., apposition of the aponeurotic edges should be the primary goal,
and if specialist approaches such as the component separation technique are employed, fascial apposition is usually
achievable.
The laparoscopic approach is somewhat different in that
in most cases it does not close the fascial layer but bridges
the fascial defect with a prosthetic mesh. In this technique it
is vital to establish a signi fi cant overlap of the mesh beneath
the native fascia. Laparoscopically, the prosthetic mesh will
always be in the subaponeurotic plane. In an inguinal hernia
100 D.H. Bennett
Fig. 6.4 Intraperitoneal placement can be reinforced by an extraaponeurotic stent
repair, the mesh is placed in the preperitoneal space using
either a transabdominal or totally extraperitoneal approach.
The laparoscopic repair of incisional and ventral hernias
will, on the other hand, generally place the prosthesis in the
intraperitoneal position. However, as the technique has
developed, the prosthetic mesh may now be placed preperitoneally, via a transabdominal approach, for some anterior
abdominal wall hernias (e.g., Spigelian hernias and incisional hernias through Pfannenstiel incisions).
There are now numerous varieties of prosthetic pre-shaped
or preformed devices that have been designed for the repair
of inguinal hernias. In some cases, these have been used for
the repair of incisional or ventral hernias as well. These are
too numerous and their methodologies so variant that they
are discussed in detail in Chap. 7 . One point that should be
emphasized, however, is that all of these products are inserted
with an individual technique speci fi c for that prosthetic
device. Deviation from this methodology may subject the
patient to an increased incidence of complications or
recurrence.
Summary: Recommendations
The patient must be appropriately prepared for theater •
and adequately resuscitated, if necessary, before any
operation is undertaken.
The fascial edges should be de fi ned, and the hernia sac •
contents reduced.
The fascial edges should be apposed by a method which •
maintains tissue strength in excess of 3 months (unless a
laparoscopic intraperitoneal technique is employed).
If a primary closure is performed, a mono fi lament nonab-•
sorbable synthetic suture such as polypropylene or nylon
is preferred.
The knot should be tied carefully and instrumentation of •
the suture material itself avoided.
If the subcutaneous fatty later is closed, an absorbable •
suture which causes little reaction is recommended—
polyglactin 910 or polydioxanone is suitable.
Closed suction drains may be used where there is a •
possibility of seroma or hematoma formation.
For skin closure, the technique should leave no skin mark-•
ings from sutures, cause a minimal reaction, and have a
low incidence of infection and sinus formation.
Recommended techniques include polyglactin 910 or
polydioxanone sutures, skin tape, or fi brin glue.
The use of an appropriate mesh prosthesis for the majority •
of hernia surgery is recommended.
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