Incisional ventral hernias: Review of the literature and recommendations regarding the grading and technique of repair
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Incisional ventral hernias: Review of
the literature and recommendations
regarding the grading and technique
of repair
The Ventral Hernia Working Group: Karl Breuing, MD,a Charles E. Butler, MD, FACS,b Stephen
Ferzoco, MD, FACS,a Michael Franz, MD,c Charles S. Hultman, MD, MBA, FACS,d
Joshua F. Kilbridge,e Michael Rosen, MD,f Ronald P. Silverman, MD, FACS,g and
Daniel Vargo, MD, FACS,h Boston, MA, Houston, TX, Ann Arbor, MI, Chapel Hill, NC, San Francisco, CA,
Cleveland, OH, Baltimore, MD, and Salt Lake City, UT
Despite advances in surgical technique and prosthetic technologies, the risks for recurrence and infection
are high following the repair of incisional ventral hernias. High-quality data suggest that all ventral
hernia repairs should be reinforced with prosthetic repair materials. The current standard for reinforced
hernia repair is synthetic mesh, which can reduce the risk for recurrence in many patients. However,
permanent synthetic mesh can pose a serious clinical problem in the setting of infection. Assessing
patients’ risk for wound infection and other surgical-site occurrences, therefore, is an outstanding need.
To our knowledge, there currently exists no consensus in the literature regarding the accurate assessment
of risk of surgical-site occurrences in association with or the appropriate techniques for the repair of
incisional ventral hernias. This article proposes a novel hernia grading system based on risk factor
characteristics of the patient and the wound. Using this system, surgeons may better assess each patient’s
risk for surgical-site occurrences and thereby select the appropriate surgical technique, repair material,
and overall clinical approach for the patient. A generalized approach and technical considerations for
the repair of incisional ventral hernias are outlined, including the appropriate use of component
separation and the growing role of biologic repair materials. (Surgery 2010;148:544-58.)
From Brigham and Women’s/Faulkner Hospital, Harvard Medical School,a Boston, MA; University of Texas,
M. D. Anderson Cancer Center,b Houston, TX; University of Michigan Health System,c Ann Arbor, MI;
University of North Carolina at Chapel Hill,d Chapel Hill, NC; Kilbridge Associates,e San Francisco, CA;
University Hospital, Case Medical Center,f Cleveland, OH; University of Maryland School of Medicine,g
Baltimore, MD; and University of Utah Health Science Center,h Salt Lake City, UT
THE REPAIR OF INCISIONAL VENTRAL HERNIAS is a com- the repair should be reinforced, and, if so, what
mon surgical procedure; in the United States, it type of material should be used. One reason for
is estimated that 250,000 ventral hernia repairs these controversies is the lack of consensus as to
are performed each year.1 The indications for when specific techniques and materials should be
repair are well established. However, controversies applied. In addition, a controversy has developed
exist with regard to technique of repair, whether as to what the most important endpoint is in the
repair of a ventral hernia: surgical-site occurrence
Supported by funding for the VHWG provided by LifeCell Cor- (SSO) or hernia recurrence.
poration, Branchburg, NJ. Editorial support was provided by The American Medical Association published a
Medisys Health Communications, High Bridge, NJ. Writing system for the development of evidence-based
assistance provided by Joshua Kilbridge of Kilbridge Associates,
San Francisco, CA.
guidelines that provides for best-practice measures
to be employed in patient care.2 Over the last 15
Accepted for publication January 14, 2010.
years, this system has been used in various areas
Reprint requests: Michael Franz, MD, University of Michigan
Health System, 2922H Taubman Health Care Center, 1500 E. of medicine to arrive at best-care recommenda-
Medical Center Drive, Ann Arbor, MI 48109-5331. E-mail: tions. To date, no guidelines have been established
mfranz@umich.edu. to address ventral hernia repair.
0039-6060/$ - see front matter A Ventral Hernia Working Group (VHWG) has
Ó 2010 Mosby, Inc. All rights reserved. been established to evaluate new technologies and
doi:10.1016/j.surg.2010.01.008 techniques as they apply to ventral hernia repair.
544 SURGERYSurgery Breuing et al 545
Volume 148, Number 3
Table I. Recommendations of the VHWG for the technique of repair of incisional ventral hernias3,6-9,31,32,62
Strength of Level of
Recommendation recommendation evidence Evidence
6
1. Reinforcement recommended for repair 1 A/B Burger et al
of all incisional ventral hernias Espinosa-de-los-Monteros et al7
Luijendijk et al3
2. Centralize and reapproximate rectus 1 C de Vries Reilingh et al8
muscles when feasible under physiologic Espinosa-de-los-Monteros et al7
tension Kolker et al9
VHWG opinion
3. Reduce bioburden prior to repair 1 B Mangram et al32
VHWG opinion
4. Placement of repair material: Underlay 2 B Awad et al31
is the recommended technique for the Espinosa-de-los-Monteros et al7
placement of appropriate repair material Korenkov et al62
for open and laparoscopic repairs; overlay VHWG opinion
placement of repair material should only
be considered when complete fascia-to-
fascia repair has been achieved
5. In the setting of gross, uncontrolled 1 C VHWG opinion
contamination, it is appropriate to
consider delayed repair
This group has a common interest in studying system and recommendations, and the application
ventral hernia as a complex process, similar to that of the recommendations to clinical practice.
for other surgical diseases. One of the topics that
has been addressed is the stratification of patients BACKGROUND
with a ventral hernia regarding risk for postoper- Despite significant advances in hernia repair
ative SSO, specifically surgical-site infection. The techniques and technologies, recurrence rates
goal of this review is to stratify patients by their risk following standard ventral herniorrhaphy remain
for postoperative SSO and to identify the most unacceptably high. Evidence from the seminal
favorable techniques for addressing ventral hernia randomized, prospective, controlled trial con-
repair in each patient population. ducted by Luijendijk et al3 suggests that nearly one
There are few randomized controlled trials in quarter of ventral hernias repaired with synthetic
this field and few head-to-head studies of devices mesh recur within 3 years; the rate approaches 50%
or techniques. Many studies are limited by small for primary repair alone. In addition, the risk of
sample size, lack of comparator group, short hernia recurrence increases with each additional
follow-up, vague endpoints, variations in surgical operation. This relationship was illustrated in a ret-
technique, and differing definitions of complica- rospective cohort study of a population-based hospi-
tions. It is the contention of the VHWG, however, tal discharge database.24 The investigators reported
that sufficient evidence exists to recommend that 12% of patients undergoing incisional hernia
certain principles for an overall approach to the repair required at least 1 subsequent reoperation
assessment and repair of incisional ventral hernias within 5 years; the length of time between reopera-
and that these recommendations will contribute to tions was progressively shorter after each additional
improved patient outcomes. hernia repair. The 5-year rate of reoperation was
The recommendations of the VHWG describe 24% after the first reoperation, 35% after the sec-
evidence-based options for the selection of surgical ond, and 39% after the third; the 7-year rate after
techniques and appropriate reinforcement mate- 3 reoperations approached 50%. These data under-
rial (Tables I and II).3-21 These guidelines are graded score the importance of minimizing the risk for sub-
according to strength of recommendation and sequent reoperations by employing the best
supporting evidence in accordance with previously evidence-based approach to the first hernia repair.
described methods (Table III).1,22,23 This review In 1990, Ramirez et al published their work on
outlines the history of the clinical problem, the local tissue transfer for the repair of ventral
rationale and literature supporting the grading hernias.25 This demonstration ushered in a new546 Breuing et al Surgery
September 2010
Table II. Recommendations of the VHWG for choice of repair material for incisional ventral hernias, by
grade4,5,11-21
Strength of Level of
Recommendation recommendation evidence Evidence
Grade 1 Choice of repair material by surgeon preference 1 C VHWG opinion
and patient factors
Grade 2 Increased risk for surgical site occurrence 1 B Dunne et al12
suggests additive risk of permanent synthetic Finan et al13
repair material, and potential advantage for Pessaux et al14
appropriate biologic reinforcement Petersen et al20
VHWG opinion
Grade 3 Permanent synthetic repair material generally 1 B Diaz et al5
not recommended; potential advantage to Houck et al11
biologic repair material Jones et al18
Kim et al4
Grade 4 Permanent synthetic repair material not 1 A Diaz et al5
recommended; biologic repair material Jones et al18
should be considered Kim et al4
Paton et al16
Patton et al15
Sczczerba et al19
van’t Riet et al21
Voyles et al17
era in hernia repair, where incisions to release known best practices in each core area determined
fascia allowed for a tension-free closure of the to be important to a successful ventral hernia
midline. In an effort to improve recurrence rates, repair. These articles were graded based on level
synthetic mesh was employed to reinforce hernia of evidence and used to develop the recommen-
repairs.6 However, there were significant complica- dations, grading system, and treatment algorithm.
tions associated with use of synthetic mesh, includ-
ing infection of the prosthesis and the formation RESULTS OF LITERATURE REVIEW
of enterocutaneous fistulae.17,26-28 In the late Initial discussions identified SSO and recur-
1990s, biologic repair materials were introduced rence as the 2 main issues in ventral hernia repair.
as a possible ventral hernia solution. Although For SSO, patient factors, wound factors, and
multiple products are available for use, no consen- choice of implant were deemed to be most impor-
sus exists as to the indicated patient population, tant. For recurrence, surgical technique was
how they should be implanted, and their overall thought to be most important, although patient
risk of complication and recurrence. and wound factors should also be considered. A
search of the literature identified various factors
THE VHWG PROCESS related to the status of the patient and wound that
In September 2008, the VHWG met for a 2-day should be addressed when evaluating the overall
summit with the goal of developing an initial complication risk in a patient with ventral hernia
statement regarding the repair of incisional ventral (discussed in the following paragraphs).
hernias. The group consisted of 8 surgeons (4 Infection and other SSOs. Common SSO fol-
general and 4 plastic), all of whom have extensive lowing ventral hernia repair include infection,
experience in abdominal wall reconstruction. The seroma, wound dehiscence, and the formation of
purpose of the summit was 2-fold: (1) to propose a enterocutaneous fistulae. Each of these complica-
grading system to guide surgeons in the assessment tions conveys morbidity and the risk for additional
of patients with incisional ventral hernias with sequelae. Each also relates to the management of
regard to risk for SSO, especially infection; and the wound and to risks associated with the use of
(2) to propose evidence-based recommendations repair materials. A wound dehiscence, for exam-
regarding the approach to advanced surgical tech- ple, may lead to exposure of the repair material; if
niques for the repair of incisional ventral hernia. the material is a permanent synthetic mesh, then it
All aspects related to hernia repair were evaluated will likely require removal because of continued
and broken down to their core components. A risk for infection.3 Infection is a common and sig-
literature search was then undertaken to identify nificant postoperative occurrence that increasesSurgery Breuing et al 547
Volume 148, Number 3
Table III. Grading of recommendations22
Grade of recommendation Type of evidence Strength of recommendation
1: Strong A: High-quality evidence RCTs without important Strong recommendation that
recommendation limitations, or can be applied to most
overwhelming evidence patients and circumstances
from observational studies
B: Moderate-quality RCTs with important
evidence limitations or strong
evidence from
observational studies
C: Low-quality evidence Observational studies Strong recommendation, but
or case series may change when higher
quality evidence becomes
available
2: Weak A: High-quality evidence RCTs without important Weak recommendation, best
recommendation limitations, or action may depend on
overwhelming evidence circumstances or other
from observational factors
studies
B: Moderate-quality RCTs with important
evidence limitations or strong
evidence from
observational studies
C: Low-quality evidence Observational studies Very weak recommendation;
or case series other alternatives may be
equally reasonable
RCT, Randomized controlled trial.
the risk of hernia recurrence.29 Studies have re- Table IV. Comorbidities shown to increase the risk
ported rates of infection following ventral hernia for postoperative infection12-14,32
repair ranging from 4% to 16%, compared with Smoking
only 2% following other clean surgical proce- Diabetes
dures.3,11-13,30 In a study by Houck et al, a history COPD
of previous wound infection predicted greater CAD
risk for new infection in a group of patients under- Nutritional status
going incisional hernia repair.11 Forty-one percent Immunosuppression
of patients with previous wound infection had a Chronic corticosteroid use
new infection versus 12% of patients with no Low serum albumin
Obesity
history of wound infection (P < .05).
Advanced age
Wound infection appears to significantly in-
crease the risk for hernia recurrence.29 In the COPD, Chronic obstructive pulmonary disease; CAD, coronary artery
disease.
study by Luijendijk et al, for example, the rate of
recurrence among patients with postoperative in-
fection was 80%, compared with 34% for those Comorbidities and risk for infection. Several
without infection (relative risk [RR] versus no in- comorbidities have been identified that increase
fection: 4.3; P = .007).3 Previously, Awad et al pro- the risk of infection following hernia repair (Table
posed a classification system that cited 2 factors IV).12-14,32 Analyses of the National Surgical Qual-
influencing recurrence following ventral hernia re- ity Improvement Program (NSQIP) database have
pair with prosthetic repair material: patient factors reported that corticosteroid use, smoking, coro-
(increased intra-abdominal pressure, diminished nary artery disease, chronic obstructive pulmonary
tissue integrity) and technical factors (infection, disease, low preoperative serum albumin levels,
lateral mesh distraction, missed hernia). They esti- prolonged operative time, and use of absorbable
mated that more than 75% of all recurrence is due synthetic mesh (likely a surrogate for more com-
to infection and inadequate repair material fixa- plex procedures) were significant independent
tion and/or overlap.31 predictors of wound infection.12,13 Findings from548 Breuing et al Surgery
September 2010
other studies suggest that age and obesity are inde- matrix repair material was significantly superior
pendent predictors of infectious complications.14 to polytetrafluoroethylene (PTFE) in terms of the
Guidelines for the prevention of surgical-site infec- ability to allow for clearance of Staphylococcus aureus
tions32 also cite altered immune response and nu- inoculate at the level expected for contamination
tritional status as risk factors for wound infection. (P = .002).42 Studies in animal models also suggest
The presence of individual comorbidities may that certain biologic repair materials can be placed
increase the risk for postoperative infection as in contact with the bowel. In one study, acellular
much as 4-fold.13 dermal matrices placed directly over the bowel
Permanent synthetic mesh and infection. Syn- were shown to better resist visceral adhesions in
thetic mesh is currently the most common repair ventral hernia repair sites compared with polypro-
material used for reinforcement of ventral her- pylene mesh (P = .004).34
nias.1 However, despite significant advantages such Clinical studies have reported good outcomes
as reduced recurrence rates, ease of use, and com- with some biologic repair materials for incisional
paratively low cost, permanent synthetic mesh has hernia repair in high-risk patient groups. In these
certain drawbacks. These disadvantages include in- reports, patients could be managed nonsurgically
creased risk for visceral adhesions to the repair even when their wound became frankly in-
site, erosion into the bowel leading to formation fected.4,5,15,38,39 Some biologic repair materials
of enterocutaneous fistulae and/or bowel obstruc- have been used successfully to repair large contam-
tion, extrusion of the repair material, and infec- inated and/or irradiated abdominal wall defects in
tion.17,18,26,33-35 For example, permanent synthetic patients with cancer when placed directly over the
mesh can complicate the treatment of postopera- bowel.43,44
tive infection. In this setting, permanent synthetic
mesh often requires later surgical removal, necessi- GRADING SYSTEM
tating reoperation.8,16,19-21,36 Following removal of The choice between synthetic and biologic
an infected prosthesis, the surgeon is left with a repair material for many surgeons is often based
contaminated field and a hernia deficit larger on several considerations including cost, choice of
than the original that still requires a repair mate- technique (eg, open versus laparoscopic), techni-
rial. Data suggest that reimplantation of synthetic cal expertise, and the risk for SSO. Due to these
prostheses into contaminated fields leads to a complex considerations, surgeons would benefit
high rate of reinfection.37 from an assessment tool that helps them develop
Multiple pathways may lead to infection of patient assessment strategies, including the selec-
synthetic mesh. Patients may have acute postoper- tion of appropriate repair material based on each
ative mesh infection, or dehiscence of the wound patient’s risk for developing SSO. The VHWG
that may expose the mesh, leading to colonization proposes an SSO-risk grading system as an instru-
and infection of the prosthesis. Reoperation ment to help surgeons stratify patients’ risk of
through synthetic mesh may also lead to infection. developing postoperative complications (Fig 1).
Furthermore, seromas that develop may become The novel grading system described herein is
infected, leading to subsequent contamination intended as a framework for the assessment of risk
and removal of the prosthesis.8,17,18,33 for SSO based on characteristics of individual
Choice of prosthetic repair material. When risk patients and hernia defects. The instrument is
for SSO is deemed to be high based on assessment based on the best available evidence, but will benefit
of risk factors, surgeons may consider the use of from vetting and validation through clinical use and
biologic repair materials in place of permanent study. The grading system is proposed as an initial
synthetic mesh, because of their ability to support stratification of risk factors and, it is hoped, to serve
revascularization. Some biologic repair materials as a framework for future research. The system
have been shown to remain intact even in the consists of 4 grades (Fig 1). These grades do not
setting of active infection; these materials are more represent discrete or didactic categories, but rather,
resistant to infection and do not require removal salient points along a continuum of risk from low-
when exposed or infected.4,15,38,39 Some biologic risk (eg, healthy patients with uncomplicated
repair materials have also demonstrated antimicro- wounds) to high-risk (eg, patients with multiple
bial activity in vitro and in animal models,40 and comorbidities and uncontrolled infection).
the ability of certain biologic prostheses to support Grade 1 (low risk) captures those patients who
revascularization may contribute to clearance of have no comorbidities, no history of wound infec-
bacteria.41 A recent study in a rabbit model, for ex- tion, and no evidence of contamination; typically
ample, found that a human acellular dermal these are younger, healthy individuals.Surgery Breuing et al 549
Volume 148, Number 3
Grade 1 Grade 2 Grade 3 Grade 4
Low Risk Co-Morbid Potentially Infected
Contaminated
• Low risk of • Smoker • Previous wound • Infected mesh
complications • Obese infection • Septic dehiscence
• No history of • Diabetic • Stoma present
wound infection • Violation of the
• Immunosuppressed
gastrointestinal
• COPD tract
Fig 1. Hernia grading system: assessment of risk for surgical site occurrences. Wound infection defined as being con-
tained within the skin or subcutaneous tissue (superficial), or involving the muscle and/or fascia (deep).13
Grade 2 (comorbid) includes patients who have because of the presence of active infection. Con-
comorbidities that increase the risk for surgical-site versely, relatively large hernias in a healthy individ-
infection (Table IV), but who do not have evidence ual may be considered grade 1 if there are no
of wound contamination or active infection. The comorbidities or signs of contamination, such as
relative contribution of different comorbidities is a violation of the bowel or history of wound infection.
matter for consideration and debate. To our knowl- There are characteristics of the patient, defect,
edge, no data currently exist that dictate which and surgical site that may influence the risk for
comorbidities carry the most weight, or which recurrence as well as SSO. For example, a greater
combination of comorbidities increases risk. number of previous repairs increases the risk of
Similarly, there are only minimal data to delineate hernia recurrence.24 For the current statement,
the tipping point for a characteristic to be consid- however, the VHWG concluded that there are still
ered a comorbidity (eg, how recent a history of insufficient data in the literature to reliably grade
infection, how much smoking, what degree of the risk of recurrence according to the proposed
malnutrition, how much corticosteroid use). grading scale. It was also agreed that inclusion of
Certain thresholds have been described. Thresh- hernia recurrence risk in the grading scale would
olds at which the risk for infection increases include make it too complex for its intended purpose,
blood glucose $110 mg/dL (hemoglobin A1c >7.0) which is to serve as a simple and memorable guide
and age $75 years.45,46 Further research is required assessing a patient’s risk of SSO.
to better understand the contribution of comorbid-
ities to risk. Until such data become available, VHWG APPROACH TO THE TECHNIQUE FOR
surgeons must rely on their clinical judgment. THE REPAIR OF INCISIONAL VENTRAL
Grade 3 (potentially contaminated) is a higher- HERNIAS
risk category based on evidence of contamination The application of advanced surgical techniques
of the wound. Factors that suggest contamination and materials may reduce the risks of recurrence
include the presence of a nearby stoma, violation and SSO such as infection. With the goal of mini-
of the gastrointestinal tract, or history of wound mizing recurrence and complications, the VHWG
infection. Grade 4 (infected) patients are at high- offers evidence-based recommendations regarding
est risk for SSO. Characteristics in grade 4 include technical approaches to the repair of incisional
active infection, especially infected synthetic mesh, ventral hernias (Table I). Although these recom-
and septic dehiscence. Each of these grades rep- mendations pertain mainly to open repairs, laparo-
resents a wide swath of risk and patient types. scopic approaches will be discussed briefly.
Assessment of risk, therefore, will continue to rely The recommendations are not intended to be
to some degree on individual surgeon judgment prescriptive or definitive but to serve as principles
and experience. The inclusion criteria for each to guide the selection of surgical techniques. The
grade will be further refined as new data regarding VHWG noted significant variation in technical
comorbidities and outcomes become available. details between surgeons, both within the panel
Each grade relates to the aforementioned risk and in the community, and concluded that any
factors for SSO but does not consider the size or extensive discussion of technique is beyond the
complexity of the defect or the proposed approach scope of this article. Therefore, the details of the
to repair. For example, relatively small hernias with techniques cited in this statement are not fully
infected mesh would still be considered grade 4 described herein.550 Breuing et al Surgery
September 2010
Table V. Principles for the repair of incisional reapproximate the rectus muscles along the mid-
ventral hernia line for ventral hernia repairs to the extent possi-
Optimize patient condition ble. This step attempts to restore the functional,
Nutritional status innervated abdominal wall and create a true dy-
Blood sugar levels namic repair without undue tension. The phrase
Smoking cessation ‘‘without undue tension’’ refers to the attempt to
Prepare wound restore normal physiologic tension. The abdomi-
Reduce bioburden nal wall is a load-bearing structure and reacts
Take down adhesions, fistulae dynamically to internal and external forces (hence
Reapproximate midline to the extent possible using ‘‘dynamic repair’’). Too little tension in a hernia
component separation when appropriate repair results in wound edge separation and poor
Use appropriate reinforcement material
collagen organization in the incision; too much
Consider biologic repair material in patients at
tension leads to ischemia and wound dehiscence.
increased risk for surgical-site occurrences
Physiologic tension attempts to achieve a balance
between these opposing outcomes.48
The overall principles agreed on by the VHWG Techniques for the repair of ventral hernias
(Table V) are optimization of the patient, preparation commonly used by the VHWG and community
of the wound, centralization and reapproximation of surgeons include retrorectus (ie, Rives-Stoppa pro-
the rectus muscles along the midline to the extent cedure) and component separation. Retrorectus
possible, and the use of appropriate prosthetic repair repair has been widely employed in Europe and is
material to reinforce the closure. Surgical principles considered by some surgeons to be the standard
are described in relation to each of the 4 grades of for repair of ventral hernias. The technique allows
risk in the grading system described above and will for placement of repair material behind the defect
focus primarily on open repair. without contacting the viscera. The technique of
Patient optimization. Patient optimization in- retrorectus repair is described in detail by other
cludes encouraging smoking cessation ($4 weeks authors.49,50 Consideration should be given to the
preoperatively), maintaining blood glucose levels use of biologic or synthetic repair materials with
(Surgery Breuing et al 551
Volume 148, Number 3
biologic repair material overlay.7 This study re- preferred over synthetic mesh for use in infected
ported a significantly lower recurrence rate when fields and should be strongly considered when
component separation was reinforced with bio- contamination is suspected (Table II). The
logic repair material (0%, component separation VHWG also notes that the increased risk for SSO
plus overlay versus 13%, component separation associated with comorbidities within grade 2 may
alone; P = .006). One randomized, prospective trial suggest potential advantages to some biologic re-
compared component separation to primary re- pair materials, depending on choice of technique
pair with expanded PTFE (ePTFE).8 An interim (eg, open versus laparoscopic) and the balance
analysis reported hernia recurrence in 10 of 19 pa- of benefits and risks. It should be emphasized
tients in the component separation group (mean that this suggestion is based on the presumption
time to recurrence, 7 months) and 4 of 18 in the that certain patients with comorbidities (ie, grade
ePTFE group (mean time to recurrence, 22 2) will, in fact, develop SSOs such as wound infec-
months). Seven patients in the ePTFE group had tion, and that biologic repair materials may facili-
an infection of the mesh that required removal tate management of infection without
of the prosthesis, followed by reconstruction using necessitating removal. To date, we have found no
component separation. It should be noted, how- published controlled clinical studies comparing bi-
ever, that no published data have been found ologic and synthetic repair materials in this patient
directly comparing component separation to pri- population.
mary repair alone (or any other repair technique), Although the VHWG does not make any recom-
nor are there any prospective data evaluating the mendation regarding choice of specific prosthetic
addition of prosthetic repair material to compo- repair materials, certain features of synthetic and
nent separation. biologic repair materials should be considered dur-
ing the selection process. The VHWG calls attention
SELECTION AND USE OF PROSTHETIC to specific characteristics such as adequate strength,
REPAIR MATERIAL ease of handling during procedures, ability to resist
Level 1A data from the study by Luijendijk et al adhesions when placed in contact with the bowel,
indicate that all clean, grade 1 ventral hernia and reduced risk of infection through support for
repairs should be reinforced with some type of tissue incorporation and revascularization.
repair material.3,6 Even in the small hernias in rel- Synthetic repair materials. Synthetic meshes are
atively healthy patients included in this study (fas- most often categorized as macroporous, micropo-
cial defect length or width #6 cm), the use of rous, or composite.61,62 Macroporous meshes
prosthetic repair material halved the rate of recur- include monofilament and double-filament polypro-
rence, both over short-term (23% vs 46%; P = pylene, among many others. These materials have
.005)3 and longer-term (32% vs 63%; P < .001) fol- large pore sizes that allow for in-growth of scar tissue.
low-up.6 Based on these data, the VHWG recom- When placed in contact with abdominal viscera, mac-
mends the use of prosthetic repair material to roporous meshes are associated with the formation
reinforce the repair of all incisional ventral her- of bowel adhesions and obstructions and enterocuta-
nias, regardless of whether or not the midline fas- neous fistulae.63,64 Therefore, these materials
cia can be reapproximated. should be avoided or used in combination with vas-
The diversity of synthetic and biologic repair cularized tissue (eg, greater omentum, hernia sac)
materials available for the reinforcement of hernia or antiadhesive barriers when contact with the bowel
repair complicates the selection of an appropriate is likely. Microporous meshes, such as ePTFE, have a
prosthesis. At least 80 different prosthetic mate- smaller pore size that does not allow for tissue in-
rials are available for hernia repair,60 and the char- growth, but may lead to encapsulation and the persis-
acteristics and types of prostheses vary considerably tence of bacteria. Therefore, microporous mesh has
even within the classes of synthetic and biologic a lower affinity for adhesions, but may be more sus-
materials. The choice of material may be based ceptible to infection.
on a variety of considerations, including character- A wide variety of composite materials is now
istics of the patient and defect, surgeon familiarity available that combine different qualities, such as
with material, and cost. The risk for SSO and sub- having macroporous mesh on one side to promote
sequent infection may determine the selection of a tissue in-growth and microporous mesh on the
synthetic versus a biologic repair material. Based other to reduce risk for adhesions to the mesh (eg,
on the grading system described above, the polypropylene/ePTFE). Synthetic meshes with
VHWG recommends that biologic repair materials antiadhesive coatings have also been developed.
with specific characteristics (see below) are Such coatings include nonabsorbable (eg, titanium,552 Breuing et al Surgery
September 2010
polyurethane) and absorbable coatings (eg, omega- cross-linked, intact biologic repair material into na-
3 fatty acid, collagen hydrogel, oxygenated regen- tive tissue was demonstrated in the same nonhuman
erated cellulose). Preclinical evidence suggests primate model. These results are similar to those re-
reduced risk of adhesions to composite and coated ported in clinical studies.44,79 In one study of ab-
synthetic meshes compared with traditional dominal repair following harvest of transverse
synthetic meshes.65-69 The relative benefits of these rectus abdominus musculocutaneous flaps for
different prostheses with regard to adhesion forma- breast reconstruction, biopsies of the biologic re-
tion and risk for infection vary according to pair material showed similar cell density, vascula-
different study models, methodologies, and out- ture, and collagen orientation to those of normal
comes.63,67,70-73 Furthermore, prospective data are abdominal fascial tissue.79 A second study found
lacking regarding the clinical benefits of these that explanted biologic repair material from an irra-
prostheses for ventral hernia repair, and no compar- diated, contaminated abdominal wall repair site 14
ative clinical data are currently available. months after implantation demonstrated remodel-
Finally, a new category of lightweight mesh is ing of the biologic repair material, including revas-
currently being used in both open and laparo- cularization and cellular repopulation.44
scopic hernia repairs. There are data to suggest It should be emphasized that no comparative
better functional outcomes than those achieved trials have been performed to date evaluating
with traditional synthetic mesh, although definitive different biologic repair materials in incisional
studies are lacking.74 hernia repair, and differentiation between pro-
Biologic repair materials. Biologic repair mate- ducts is based on early findings with a limited
rials are an equally diverse and expanding class. number of the available prostheses. Data describ-
Certain specific characteristics are thought to con- ing the qualities of biologic repair materials are
tribute to the successful use of particular biologic only available for certain prostheses. Similar ani-
repair materials in the setting of contamination or mal and clinical studies are awaited for the major-
low-grade infection, whereas others are contra- ity of products in this class.
indicated. These properties include intact extra-
cellular matrix and the ability to support tissue TECHNIQUE OF PLACEMENT
regeneration through revascularization and cell There are technical aspects of the use of bio-
repopulation in a clinically relevant timeframe. It logic repair material that must be considered in
has been hypothesized that resistance to infection order to achieve successful outcomes. Studies have
for some biologic repair materials may be related documented high rates of seroma, diastasis, bulg-
to the in-growth of cells and vasculature.75 Numer- ing, and recurrence with biologic repair mate-
ous animal studies have shown that altering the ex- rials80,81; critical techniques of placement were
tracellular matrix through suboptimal processing described that may influence the risk of these com-
and/or crosslinking may have a negative impact plications.43 In one study, recurrence was reduced
on host response to the repair material.76,77 The when component separation was combined with
neovascularization demonstrated in studies of biologic repair material; conversely, bridging with
some biologic repair materials may allow these biologic repair material without reducing the size
materials to better resist infection when placed in of the defect was associated with a recurrence
a potentially contaminated field.42,75 rate of 80%.81 The tensile qualities of repair mate-
The ability of some biologic repair materials to rials differ and may impact technique. The VHWG
support regeneration is based on studies in animal notes that most biologic repair materials should be
models that describe the immunologic response of implanted under appropriate tension to help pre-
the host to the prosthesis. Positive recognition (ie, vent the development of laxity. (This use of tension
recognition of the prosthesis as ‘‘self’’) leads to for repair material implantation should be distin-
regeneration and integration of the repair material guished from the avoidance of undue tension---or
into native tissue. Negative recognition (ie, recog- physiologic tension---that describes the fascial clo-
nition of the prosthesis as foreign) may lead to sure.) Surgeons should be aware that the use of a
resorption or encapsulation.76,78 Resorption and biologic repair material necessitates technical
encapsulation have been demonstrated with several familiarity with its appropriate placement.
biologic repair materials in a nonhuman primate Overlay, underlay, or interpositional placement
model of abdominal wall repair.76 The investigators of prosthetic repair material. In open incisional
suggested that the lack of integration and tissue re- hernia repair, prosthetic repair material may be
generation with these materials may account for placed to reinforce a primary repair or to bridge a
poor initial wound healing. Integration of 1 non-- remaining defect if reapproximation of theSurgery Breuing et al 553
Volume 148, Number 3
midline is not possible. The repair material may be should be based on surgeon preference and pa-
sutured superficial to the primary repair or fascial tient factors. Grade 2 encompasses patients with
edges (overlay), deep to the primary repair or comorbidities, such as smoking, diabetes, or mal-
fascial edges (underlay), or to the edge of the nutrition (Table IV). Data from analyses of the
defect with minimal overlap (interpositional). The NSQIP database and other studies suggest that pa-
overlay technique is easier to perform, does not tients in grade 2 have a wound infection rate that is
require devascularization of the rectus, and pre- 4-fold greater than what is predicted based solely
vents contact between the repair material and the on wound classification.12,13 Current published ev-
underlying viscera. Overlay placement also allows idence does not delineate the relative contribution
for reinforcement of the lateral releasing incisions of each comorbidity to increased risk. Ongoing
after component separation, if desired. Overlay and future clinical studies may provide a more
placement, therefore, may be preferred for types thorough evidence-based estimate of which and
of synthetic mesh that are associated with forma- how many comorbidities contribute most signifi-
tion of bowel adhesions to minimize the risk that cantly to increased risk of SSO. In the absence of
the mesh may erode into the abdominal compart- more definitive data, the VHWG notes that the in-
ment and become exposed to the viscera. creased risk associated with these comorbidities
There are also theoretical advantages to the suggests a potential advantage for the use of appro-
placement of repair material as an underlay. When priate biologic repair material for reinforcement
the material is placed deep to the abdominal of open repairs.
musculature, increases in intra-abdominal pressure Grade 3 includes patients with contamination of
press the repair material into the defect and the wound or suspicion of contamination, includ-
against the native tissue, rather than away from ing a previous wound infection. Based on the
the defect. Intra-abdominal forces may also be increased risk for infection associated with contam-
more evenly distributed across the repair material inated wounds, the VHWG notes that permanent
when placed as an underlay.82 Furthermore, cuta- synthetic mesh is generally not recommended for
neous exposure does not result in exposure of patients considered to be grade 3. Appropriate
the repair material, because the prosthesis remains biologic repair material is a good option for rein-
below the musculofascial layer. forcement in these patients, because it does not
Bridging of defects, which refers to the use of necessitate removal even in the setting of active
prosthetic repair material to span tissue gaps when infection.
reapproximation of the fascial edges is not possi- Grade 4 patients have frankly infected wounds,
ble, has been associated with high rates of recur- most notably those associated with an existing
rence and complications. Bridging may not infected synthetic mesh. Studies suggest that the
generally be recommended except in cases where replacement of infected synthetic mesh with new
component separation is not feasible or is insuffi- permanent synthetic mesh leads to a high rate of
cient to bring the fascial edges together (see reoperation and additional mesh infection and
discussion of algorithm, below).83 replacement.8 The use of permanent synthetic
The VHWG notes that underlay may be pre- mesh in patients considered to be grade 4, there-
ferred because of the theoretical advantages of this fore, is not recommended by the VHWG. In accor-
technique. However, there are no reliable data dance with the surgical principles outlined above
supporting the use of one technique over an- and in Table V, infected wounds should be thor-
other.83 Patient factors and surgeon preference oughly prepared by meticulously reducing the bio-
should also be considered. Regardless of place- burden prior to placement of repair material and
ment, repair material should overlap with intact definitive closure. No repair material should be
fascia by at least 3--5 cm.34,84-89 used in the setting of gross, uncontrolled contam-
ination, and surgeons may consider a delayed
TECHNICAL OPTIONS BY GRADE repair in such situations.
The overriding recommendation of the VHWG
regarding the repair of incisional ventral hernia is LAPAROSCOPIC REPAIR OF INCISIONAL
to reinforce the primary fascial closure with a VENTRAL HERNIA
prosthetic repair material.6 The selection of type This statement focuses primarily on the open
of repair material between biologic and synthetic repair of incisional ventral hernia. However, the
with regard to hernia grade should be based on growing popularity of laparoscopic techniques de-
risk for SSO (Table II). For patients at low risk serves discussion with relation to the grading
for SSO (grade 1), the choice of reinforcement system and recommendations of the VHWG.554 Breuing et al Surgery
September 2010
Patient assessment for risk of SSO
(Grade 1, 2, 3 or 4)
Decide on best approach for repair
(Open versus Laparascopic)
Laparascopic
Open
Defect small enough to close
Most often repaired primarily (≤2 cm): Defect too large
w/synthetic mesh Reinforce with prosthetic for primary repair
repair material
Component separation Component separation
w/complete rectus closure w/incomplete rectus closure,
plus reinforcement some bridging w/prosthetic
w/prosthetic is unavoidable
Grade 1: Choice of repair material by surgeon preference and patient factors
Grade 2: Increased risk for surgical site occurrence suggests additive risk of permanent synthetic repair
material, and potential advantage for appropriate biologic reinforcement
Grade 3: Permanent synthetic repair material generally not recommended; potential advantage to biologic
repair material
Grade 4: Permanent synthetic repair material not recommended; biologic repair material should be considered
Fig 2. Algorithm for repair of incisional ventral hernia.
Although recurrence rates following reinforced .01) over a mean follow-up period of 30--36
laparoscopic hernia repair are comparable to months, respectively.91 Postoperative inpatient ad-
those of open repair with reinforcement,90,91 there mission was also more frequent in the open group
are several documented advantages of the laparo- (28% vs 16%; P < .05). However, seromas may be
scopic approach, including smaller incisions, lower more common following laparoscopic hernia re-
risk for complications, shorter hospital stay, and pair. In the aforementioned cohort study, seromas
patient preference.90-92 A recent meta-analysis of were significantly more common in the laparo-
randomized controlled trials comparing open scopic group (16% vs 8%; P = .01). Indeed, higher
and laparoscopic incisional hernia repairs re- rates of seroma have been widely reported with lap-
ported a significantly higher rate of complications aroscopic repairs. Lower incidence of seroma in
with open repair (RR .49, P < .001 by fixed-effects open procedures may relate to the use of drains,
model; RR .53, P = .028 by random-effects which are not generally placed in laparoscopic re-
model).89 Reported complications included se- pairs. Seromas often resolve uneventfully, and
roma, abscess, incarceration, hematoma, cellulitis, many surgeons do not consider this occurrence
wound infection, bowel obstruction, and ileus. A to be pathologic unless intervention is required
single-institution cohort study comparing open due to the risk of contamination and subsequent
and laparoscopic ventral hernia repair (N = 360) infection of the seroma.82
reported major morbidities in 15% of the open In addition to a higher rate of seroma forma-
group and 7% of the laparoscopic group (P = tion, the limitations of laparoscopic repair includeSurgery Breuing et al 555
Volume 148, Number 3
the inability to restore functional abdominal wall repair. For surgeons who practice laparoscopic
anatomy. Other difficulties include the inability to repairs, patients in grade 1, many in grade 2, and
manage skin redundancy and the hernia sac. some in grade 3 may be suitable for this approach,
Current approaches to laparoscopic repair do not depending on individual risk for infection and
routinely employ extensive mobilization of tissue, other considerations. Hernias in grade 4 should be
meaning that the repair material is almost always repaired with open procedures. The same princi-
bridging some aspect of the defect. Laparoscopi- ples of selecting prosthetic repair material apply
cally inserted repair material is placed intraperito- regardless of technique (open versus laparo-
neally as an underlay below the fascial defect.82 scopic): most patients in grade 1, some in grade
These repairs do not recreate an innervated 2, and a few in grade 3 may be suitable for repair
abdominal wall under physiologic tension. with permanent synthetic mesh; all patients con-
Recently, several investigators have described sidered at increased risk for SSO (including some
minimally invasive techniques of component sep- in grade 2, most in grade 3, and all in grade 4)
aration.54 Experience with these techniques has should be considered for repair with appropriate
been reported in studies of cadavers,55 a porcine biologic repair material.
model,56 select patients with infected repair mate-
rial,57 and small comparative groups.54 Preliminary OTHER CONSIDERATIONS IN SELECTION OF
results suggest that minimally invasive techniques REPAIR MATERIAL AND TECHNIQUE
are feasible, and may be associated with fewer One key consideration in the selection of pros-
complications. thetic repair material deserves mention. Currently,
there is wide variation in the cost of available
TREATMENT ALGORITHM prostheses. For some institutions and practices,
The first step in the treatment of ventral hernia cost may limit or eliminate the use of more
is patient assessment, starting with risk factors and expensive devices. A thorough discussion of cost
size of the defect. Smaller defects (#2 cm) may be considerations is not the intended purpose of this
suitable for primary repair; larger defects where article. However, future analyses of the cost-benefit
the fascia does not meet without undue tension relationship accounting for the expense of mate-
should be reduced as much as possible. Each rials, surgical procedures, and potential complica-
patient’s risk for SSO should be assessed using tions would be greatly beneficial to practitioners
the grading system. and administrators alike.
A proposed algorithm for the treatment of inci- Many of the advanced techniques described in
sional ventral hernias is illustrated in Fig 2. Following this consensus statement require extensive hospital
assessment for risk of SSO, patients are categorized resources and a high level of training. Surgeons in
by size of defect. Very small defects may be closed pri- settings with less extensive resources may give
marily along with reinforcing prosthetic repair mate- consideration to the referral of resource-intensive
rial, potentially using a retrorectus repair. Most patients to tertiary care centers that have appro-
defects too large for primary repair can be closed priate surgical resources.
with component separation and reinforced with
prosthetic repair material. For the rare cases in SUMMARY
which component separation is not feasible or is in- Incisional ventral hernias are common and
sufficient to completely reduce the defect, surgeons challenging for surgeons. The lack of high-quality
may consider bridging the defect with prosthetic re- evidence leaves surgeons without clear guidance
pair material. (The repair material should underlie regarding the selection of technique or material.
the rectus muscles by at least 5 cm.) Examples of pa- The ultimate goal of this effort was to produce a
tients for whom component separation may not be simple, generally accepted grading system and
feasible include those with intensive radiation treat- surgical technique recommendations for the re-
ment of the abdominal wall or extensive scarring of pair of incisional ventral hernias. The first step in
the rectus muscles. Surgeons should exercise their this effort was the creation of an initial literature
judgment when considering the feasibility of compo- review and set of recommendations. This state-
nent separation. When using component separation ment represents the current state-of-the-art tech-
and/or other techniques to reapproximate the rec- nique and materials as described by thought
tus muscles, the authors find that bridging of defects leaders in the field and supported by the best
with biologic repair material is rarely necessary. available evidence. It is hoped that the grading
The nature of a laparoscopic ventral hernia system and recommendations will serve to assist
repair as currently performed leads to a bridged surgeons and stimulate discussion and research.556 Breuing et al Surgery
September 2010
As new data become available, the VHWG will with polypropylene mesh: short-term benefits versus long-
revisit this statement to reflect the evolving under- term complications. Ann Surg 1981;194:219-23.
18. Jones JW, Jurkovich GJ. Polypropylene mesh closure of in-
standing of ventral hernias. Future updates will be fected abdominal wounds. Am Surg 1989;55:73-6.
provided as data emerge and novel techniques and 19. Szczerba SR, Dumanian GA. Definitive surgical treatment of
materials are developed. infected or exposed ventral hernia mesh. Ann Surg 2003;
237:437-41.
20. Petersen S, Henke G, Freitag M, Faulhaber A, Ludwig K. Deep
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