INTRODUCTION — An estimated one-quarter of all individuals are either born with or will develop a ventral hernia in their lifetimes [1]. An estimated 348,000 ventral hernia repairs and over 300,000 ventral hernia repairs are performed annually in the United States and Europe, respectively [2,3]. In the United States, over $3.4 billion a year is spent on repairing ventral hernias [2].
Ventral hernias occur in the anterior abdominal wall and include primary ventral hernias (eg, epigastric, umbilical, Spigelian, lumbar hernias) and most incisional hernias (including parastomal hernias) [4]. Incisional hernias can develop anywhere an incision has been made but most commonly occur at the midline, given that midline incisions are most commonly used during laparotomies. Spigelian, lumbar, and parastomal hernias occur off the midline and are discussed in detail elsewhere. (See "Spigelian hernias" and "Parastomal hernia" and "Lateral abdominal wall hernia repair".)
The management of ventral hernias, both primary and incisional, will be reviewed here. The techniques of open ventral hernia repair are discussed in this topic; techniques of laparoscopic and robotic ventral hernia repair are discussed elsewhere. (See "Laparoscopic ventral hernia repair" and "Robotic ventral hernia repair".)
Component separation is often used to repair large (width >10 cm) or complex ventral hernias (eg, loss of domain). Its indications and techniques are discussed elsewhere. (See "Overview of component separation" and "Open anterior component separation techniques" and "Open posterior component separation techniques" and "Robotic component separation techniques".)
The clinical features and diagnosis of ventral hernias and the diagnosis and management of other abdominal wall hernias (eg, groin hernia) are reviewed separately:
●(See "Overview of abdominal wall hernias in adults".)
●(See "Clinical features, diagnosis, and prevention of incisional hernias".)
●(See "Classification, clinical features, and diagnosis of inguinal and femoral hernias in adults".)
●(See "Overview of treatment for inguinal and femoral hernia in adults".)
ACUTELY INCARCERATED OR STRANGULATED VENTRAL HERNIAS — Patients with an acutely incarcerated or strangulated ventral hernia require urgent surgical repair (algorithm 1). Among the 2.3 million inpatient abdominal hernia repairs performed from 2001 to 2010 in the United States, an estimated 576,000 were performed urgently [5]. The rate of emergency hernia repairs has risen from 16.0 per 100,000 person-years in 2001 to 19.2 in 2010. Among those older than 65, the rate was as high as 71.3 (male) and 42.0 (female) per 100,000 person-years.
The objective of the emergency surgery is to alleviate any acute problems (eg, bowel infarction, bowel obstruction, abdominal pain) and perform the safest and most durable repair given the clinical setting. The optimal technique of hernia repair varies depending on the anatomy, patient stability, patient comorbidities, and degree of contamination of the operative field [6].
Acutely incarcerated or strangulated hernias can be difficult to reduce due to a small fascial defect and a high risk of injuring the incarcerated organs. Thus, laparoscopy should be used cautiously in such patients. Distended bowel can easily be injured with trocar placement or manipulation with laparoscopic instruments, which could further complicate the repair. If attempted by experienced laparoscopic surgeons, good surgical judgment is required to minimize the risk of visceral injury [7]. (See 'Open versus laparoscopic repair' below.)
Contaminated field — An acutely incarcerated or strangulated ventral hernia could result in contamination of the operative field (eg, as a result of strangulated bowel or perforated viscus). Surgical options of repairing the hernia after controlling the source of the contamination include primary suture repair, mesh repair (with a biologic, synthetic, or biosynthetic mesh), and staged repair (including placement of absorbable mesh and leaving the hernia to be repaired electively at a later date). There is no consensus due to the fact that clinical scenarios are heterogenous and management needs to be individualized [8,9]. (See 'Mesh material' below and "Wound infection following repair of abdominal wall hernia", section on 'Mesh-related factors'.)
The best practice for ventral hernia in a contaminated field calls for primary suture or staged repair when safe and feasible. Mesh repair with synthetic mesh in these complex cases has been shown to be safe and effective in the hands of high-volume surgeons [10-12]. The role of biologic meshes is changing and uncertain. The role of biosynthetics remains to be delineated. The relevant data are discussed below. (See 'Mesh material' below.)
Additionally, when performing an emergency ventral hernia repair, the surgeon should use caution when creating large flaps (eg, component separation) [6,8]. Component separation is associated with a high risk of wound complications in elective settings, and its complication rate in a contaminated field may be even higher (77 percent in one study) [13]. (See "Overview of component separation".)
REDUCIBLE OR CHRONICALLY INCARCERATED VENTRAL HERNIAS — The majority of ventral hernias are either reducible or chronically incarcerated. The management principles are primarily determined by whether they are associated with any symptoms and the size of the hernia defects but can be influenced by patient comorbidities and overall health status (algorithm 1).
Asymptomatic ventral hernias — Patients with an asymptomatic or minimally symptomatic ventral hernia can be managed expectantly if they wish to avoid surgical repair [14-18]. In a large retrospective study, the incidence of acute presentation was 1.24 percent at one year and 2.59 precent at five years [19]. However, patients should be counselled that the cumulative lifetime risk of acute presentation may be high, and a nonoperative strategy may fail after the initial one to two years for most patients [6,8,20].
Symptomatic ventral hernias — Although ideally all patients with symptomatic ventral hernias should undergo surgical repair, anatomical or physiologic constraints may temporarily prohibit surgery because the risk of surgery for patients with multiple medical comorbidities may outweigh the risk of complications related to unrepaired hernia. Such constraints, however, are relative contraindications and may be mitigated with preoperative optimization [21]. During that process, the hernia is managed expectantly unless the patient presents with an acute complication such as incarceration or strangulation, in which case emergency repair is mandatory. (See 'Acutely incarcerated or strangulated ventral hernias' above.)
Relative contraindications to elective repair — Specific risk factors for ventral hernia repair include (all are relative contraindications, as acutely incarcerated or strangulated hernias must be repaired):
●Smoking – Smoking has been associated with increased risk of surgical site infection [22] and hernia recurrence [23] after ventral hernia repair. Patients seeking elective hernia repair should be counseled to refrain from smoking for a minimum of four to eight weeks prior to their operation [6,8].
●Obesity – Obesity has been associated with longer hospital stay and more surgical site infections [24], hernia recurrences [23], and readmissions after ventral hernia repair. Surgeons should not offer elective ventral hernia repair to patients with a body mass index (BMI) over 50 kg/m2 [6]. Many surgeons would not operate on patients with a BMI exceeding 40 kg/m2 [8]. Patients with a BMI between 35 and 40 kg/m2 require individualized evaluation before elective hernia repair [25]. Weight change is linearly correlated with intra-abdominal and subcutaneous fat gain or loss, but hernia dimensions increase over time regardless of weight change [26]. (See 'Obesity' below.)
●Diabetes – Poorly controlled diabetes mellitus is a well-known risk factor for postoperative complications [24]. Glycosylated hemoglobin (HbA1c) is used as a surrogate for diabetes control. An HbA1c >8 percent is prohibitive to safe elective hernia repair, while an HbA1c >6.5 or 7 percent should prompt individualized perioperative intervention aimed at risk reduction before elective surgery can be undertaken [6,8].
Other comorbidities, such as chronic obstructive pulmonary disease (COPD) with active bronchitis, congestive heart failure, and history of alcohol abuse, are also associated with higher infection and recurrence rates [22]. Because the development of ventral hernias is closely associated with the comorbid conditions described above, the morbidity of ventral hernia repair (eg, surgical site infection or hernia recurrence) may be high. Thus, preoperative risk assessment for patient selection and patient counseling are extremely important.
Multiple systems have been developed to risk stratify patients in terms of their risk of developing recurrence and wound complications following open ventral hernia repair based on factors such as obesity, concomitant procedures, and Centers for Disease Control (CDC) wound class. These systems include the Ventral Hernia Working Group (VHWG) surgical site occurrence grading system [27,28], modified VHWG grading system, Ventral Hernia Risk Score (VHRS) [27,29,30], Hernia Wound Risk Assessment Tool (HW-RAT) [31], and Carolinas Equation for Determining Associated Risks (CeDAR) score [32]. Although a high risk score does not necessarily exclude patients from surgery, it can be very useful in counseling patients [33].
The Abdominal Core Health Quality Collaborative (ACHQC) app uses preoperative and intraoperative information to estimate important 30 day and one-year outcomes following elective ventral hernia repair using mesh. Postoperative results are estimated based on outcomes from data collected by the ACHQC.
SURGICAL MANAGEMENT OF VENTRAL HERNIAS — Ventral hernias are classified as primary or incisional, with different pathophysiology and treatment outcomes:
●Primary ventral hernias are abdominal wall fascial defects not associated with any prior incision or surgery; these include common defects such as umbilical hernias or epigastric hernias as well as rare defects such as Spigelian or lumbar hernias. The recurrence rate of primary ventral hernia repair is 5 to 10 percent at two years.
●Ventral incisional hernias are fascial defects associated with prior surgery or incisions, including midline defects as well as lateral defects such as flank hernias or parastomal hernias. The recurrence rate of ventral incisional hernias can be as high as 25 to 43 percent at three years.
The surgical management of ventral hernias depends on whether the hernia is primary or incisional, the hernia width, and surgeon preference (algorithm 1):
Primary ventral hernia <1 cm — Small (<1 cm) primary ventral (eg, mostly umbilical, some epigastric) hernias can be repaired with sutures with or without mesh reinforcement [6,34]. Open repair is typically performed for such small hernias. Minimally invasive repair of small, readily identifiable primary midline ventral hernias (ie, epigastric and umbilical) in thin patients is generally not necessary and is often more invasive than open repair but may be considered for patients with obesity or other increased risks for wound infections.
Simple suture repair of small ventral hernias is a straightforward open operation. The incision is made over the palpable hernia defect, and the hernia sac is dissected sharply from the surrounding tissue of the abdominal wall until the fascia is identified circumferentially. The debrided fascial edges are sutured together using a mass closure technique. The choice of suture materials (nonabsorbable or slowly absorbable, but not quickly absorbable) and closing techniques (eg, running or interrupted, simple, mattress, or figure-of-eight) is determined by surgeon preference [34]. (See "Principles of abdominal wall closure", section on 'Fascia'.)
Mesh insertion is optional for such small hernias. However, because suturing together a thinned-out linea alba may result in higher recurrence rates [35], we suggest mesh repair of primary ventral hernias (epigastric or umbilical) that are within or at the terminus of a rectus abdominis diastasis [36]. While some surgeons do not enlarge the defect to insert mesh [37], others do [38]. Alternatively, minimally invasive repair permits not only insertion of a mesh but also the ability to anchor it to strong tissues outside the thinned-out linea alba.
Incisional ventral hernia <1 cm — Small incisional hernias often arise at trocar sites of a previous laparoscopic surgery. We suggest mesh repair of all incisional ventral hernias, including those that are <1 cm. An incisional hernia implies failed or poor healing at a previous incision. Suture repair of such hernias will likely result in a recurrent hernia.
Ventral hernias between 1 and 10 cm — Most ventral hernias encountered in daily clinical practice fall in this category. Although mesh reinforcement is generally required to properly repair these hernias, both the surgical approach (open, minimally invasive [laparoscopic, robotic]) and choice of hernia mesh (material, location) vary according to clinical scenario and surgeon preference.
Our suggestions, which are consistent with society guidelines [34], include (see 'Open versus laparoscopic repair' below):
●Open or minimally invasive mesh repair of ventral hernias between 1 and 4 cm [39]. Open repair is preferred in thin patients; minimally invasive repair is preferred in patients with obesity or other risks of developing wound infection and patients with significant diastasis recti bordering the hernia defect.
●Minimally invasive mesh repair of ventral hernias between 4 and 10 cm in a clean field [39].
Large (width >10 cm) or complex hernias — Ventral hernias with a defect width >10 cm are classified as large hernias by the European Hernia Society [4]. Complex hernias have more than one-half of the abdominal viscera outside the boundary of the abdomen (loss of domain) [40,41].
Large or complex ventral hernias are difficult to repair [42]. Although these hernias can be repaired using minimally invasive underlay, open inlay, or component separation techniques, there are very little high-quality data on the efficacy or effectiveness of each repair.
Standard laparoscopic repairs use underlay mesh, and, although there are advantages of less pain, a shorter recovery, and a lower infection rate, the subsequent repair still lacks the dynamic effects of abdominal wall muscle, and patients will still notice a bulge (called eventration) at the site of the defect with increases in intra-abdominal pressure. The repair of large defects with mesh may not reduce the discomfort, back pain, and respiratory problems when compared with component separation, which restores the dynamic muscle component to the abdominal wall.
For patients with large (sometimes called giant) ventral hernias and patients with loss of domain, we suggest using advanced techniques, such as component separation, to achieve primary fascial closure before mesh reinforcement as opposed to using mesh to bridge a fascial defect (inlay mesh method).
Pioneered by Ramirez [43], component separation is used nearly exclusively for the repair of large or complex midline abdominal wall defects and has the advantage of restoring abdominal wall function. Component separation involves dividing portions of the anterior or posterior rectus sheaths and/or a lateral oblique muscle in a manner that allows advancement of the rectus abdominis muscle by as much as 10 cm from each side to allow a fascial closure under physiologic tension (figure 1) [43-45]. Furthermore, certain posterior component separation techniques (ie, transversus abdominis release [TAR]) can also be used to repair ventral hernias narrower than 10 cm to facilitate posterior sheath closure. (See "Overview of component separation".)
Component separation can be performed using an open or robotic-assisted approach. Not all patients are candidates for a component separation technique. The indications, contraindications, and technical aspects of component separation are discussed elsewhere. (See "Open anterior component separation techniques" and "Open posterior component separation techniques" and "Robotic component separation techniques".)
CHOOSING A SURGICAL APPROACH — Ventral hernias can be repaired with sutures, mesh, component separation, or any combination of the above. Simple suture repair is performed using an open approach, while mesh repair and component separation can be performed open, laparoscopically, or robotically.
Generally speaking, very small (width <1 cm) and very large (width >10 cm) ventral hernias are repaired open, while those between 1 and 10 cm have a choice of surgical approaches. Although laparoscopic intraperitoneal onlay mesh (IPOM) repair is clearly favored for reduced wound morbidities compared with open repair, its adoption has slowed because of lingering concern about intraperitoneal mesh [46]. To hedge against potential wound complications, modern open repairs are often performed with extraperitoneal meshes, most commonly in the retrorectus position (ie, Rives-Stoppa repair with or without transversus abdominis release [TAR]). (See "Open posterior component separation techniques", section on 'Rives-Stoppa retrorectus dissection'.)
Robotic-assisted repair emulates either the laparoscopic IPOM repair or the open repair with extraperitoneal mesh placed in the retrorectus location. Although the latter seems to circumvent the disadvantages of both open (wound morbidities) and laparoscopic repairs (intraperitoneal mesh), it can be technically challenging, and devastating early complications such as linear alba or semilunaris line disruption or posterior sheath breakdown can occur [47]. (See "Robotic component separation techniques".)
Thus, for ventral hernias between 1 and 10 cm in width, it is difficult to mandate a surgical approach. Where robotic surgery is not available, we suggest laparoscopic mesh repair over open repair. The low rate of wound morbidities of laparoscopic repair makes an extraperitoneal mesh unnecessary, the potential long-term complications of an intraperitoneal mesh notwithstanding. However, that potential risk is often cited but not well documented in the literature [48-53]. Where robotic surgery is available, the choice between laparoscopic and robotic repair comes down to surgeon training, experience, and preference.
The data comparing open, laparoscopic, and robotic ventral hernia repair outcomes are discussed below.
Open versus laparoscopic repair — Open and laparoscopic techniques of ventral hernia repair have been compared in multiple randomized trials and observational studies. The preponderance of data favor laparoscopic repair for its short-term benefits of lower incidences of surgical site and mesh infection, less pain, faster recovery, and either superior or comparable long-term durability (free from recurrence) to that of open repairs [54-74], with a few studies showing equipoise [11]. (See "Laparoscopic ventral hernia repair".)
As an example, a 2014 systematic review involving 1003 patients from 11 trials found lower incidences of wound drainage (2.6 versus 67 percent) and wound infection (2.8 versus 16.2 percent) for laparoscopic incisional hernia repair compared with open hernia repair [55]. The lower rate of infection may be related to the less extensive tissue dissection needed to place the mesh compared with the open procedure. However, the incidence of bowel injury was higher for the laparoscopic group (4.3 versus 0.81 percent). No differences were identified for postoperative seroma, hematoma, bleeding, bowel obstruction, reoperation, or hernia recurrence. A 2011 Cochrane database review and a 2015 meta-analysis of trials reached similar conclusions regarding wound complication and recurrence [3,75].
Another systematic review and meta-analysis of three randomized trials and seven retrospective cohort studies found open umbilical and paraumbilical hernia repair to be associated with higher risks of wound dehiscence (odds ratio [OR] 4.99, 95% CI 1.12-22.8), wound infection (OR 2.35, 95% CI 1.23-4.48), recurrence (OR 4.06, 95% CI 1.54-10.71), and length of stay (95% CI 1.54-10.71) but a shorter operative time (mean difference -23.07, 95% CI -36.78 to -9.35) compared with laparoscopic repair [76]. When only randomized trials were analyzed, open repair was still associated with higher risks of wound infection, wound dehiscence, hematoma, seroma, and longer length of stay but not a higher recurrence rate (OR 1.52, 95% CI 0.70-3.30).
In a database study of 6855 patients undergoing umbilical or epigastric hernia repair in Denmark, open repair was associated with a significantly higher rate of readmission and reoperation due to surgical site infection (2.5 versus 0.5 percent), whereas the rate of reoperation due to a severe complication was significantly higher after laparoscopic repair (1.5 versus 0.8 percent) [77]. Recurrence rates were comparable between open and laparoscopic repair of umbilical and epigastric hernias (3.5 versus 4.2 percent).
Given the available data, we suggest that:
●Laparoscopic repair is indicated for patients at increased risk for wound complications (eg, those who are overweight or obese, who smoke, or who have comorbid conditions), hernias <10 cm in width, and off-midline hernias.
●Open repair is indicated for patients at low-risk for wound complications (ie, those who are not overweight or obese, who do not smoke, and who do not have comorbid conditions) with a low-risk hernia (ie, solitary midline primary ventral hernia such as umbilical or epigastric hernia). Open repair is also indicated for complex ventral hernias that include large defects, loss of domain, or contamination.
Robotic versus laparoscopic repair — Robotic surgery may provide another minimally invasive option for ventral hernia cases that would otherwise require an open approach. However, two trials published so far of mostly <4 cm ventral hernias showed that robotic repair with intraperitoneal mesh had similar clinical outcomes to its laparoscopic counterpart but required longer operative time at a higher cost [78-80]. Other trials are ongoing. (See "Robotic ventral hernia repair", section on 'Outcomes'.)
MESH REPAIR OF VENTRAL HERNIAS — Mesh repairs of ventral hernias vary by mesh material, mesh location, and operative approach, which are dictated by clinical scenarios, surgeon expertise, and available resources. The choice of operative approaches is discussed above, while the benefit of mesh (as opposed to nonmesh [suture] repair) and the choice of mesh material, location, and size are discussed here.
Mesh versus nonmesh repair — For all ventral hernias with a defect >1 cm in a clean field, a mesh repair is preferred over nonmesh repair [6,81]. Mesh is a required element of all laparoscopic or robotic ventral hernia repairs (see "Laparoscopic ventral hernia repair" and "Robotic ventral hernia repair") and has been shown to decrease recurrences after open ventral repair of various types of ventral hernias [37,50,82-91].
On the other hand, mesh repairs are associated with a higher rate of wound complications including infections than repairs without mesh [48,49,53,86,92]. However, it is often possible to treat the superficial wound infection with antibiotic therapy and avoid mesh removal, especially when mesh is placed in a sublay or underlay (intraperitoneal) position. However, synthetic mesh also provokes an inflammatory response so that intraperitoneal mesh has the potential for complications such as abdominal adhesion formation and late mesh erosion [48-53]. A single-center series of over 6387 mesh repairs of abdominal wall hernias (65 percent inguinal) found very low complication rates but 2.9, 3.3, and 4.4 percent of patients reporting severe or disabling symptoms postoperatively at one, two, and five years, respectively [93,94]. For patients who do not accept mesh for fear of mesh-related complications, a nonmesh (suture) repair can be performed as long as they clearly understand that the expected recurrence rate is higher.
The available evidence for mesh versus nonmesh repair of incisional or primary ventral hernia is as follows:
●Ventral incisional hernias – In a registry-based cohort study in Denmark, over 3000 patients underwent elective ventral incisional hernia repair and were followed for five years [54]. Of these patients, 1119 underwent open mesh repair, 366 had open nonmesh repair, and 1757 had laparoscopic mesh repair. Compared with nonmesh repair, mesh repair was associated with fewer reoperations for recurrences (open mesh 12.3, laparoscopic mesh 10.6, nonmesh 17.1 percent) but more reoperations for mesh-related complications (open mesh 6.1, laparoscopic mesh 4.2, nonmesh 0.8 percent). Given that 57 percent of nonmesh repairs in this study were performed for very small hernias (<2 cm), there was a selection bias against mesh repair, which likely underestimated its benefit in reducing recurrences while exaggerating its harm in causing complications [95]. Despite that, the study was still able to affirm that mesh reduced recurrence in incisional hernia repairs. The mesh-related complications reported by this study echo our caution of only using mesh for moderate- or large-sized hernias (>1 cm).
●Primary ventral hernias – In a systematic review and meta-analysis of nine studies of primary ventral hernia repairs (n = 1782), the recurrence rates were 8.2 percent after suture repair and 2.7 percent after mesh repair, but the seroma and surgical site infection rates were higher after mesh repair [82]. In a 2019 systematic review and meta-analysis of five trials [37], open mesh repair of small- or medium-sized umbilical hernias (1 to 4 cm in diameter) reduced the risk of recurrence (relative risk 0.28, 95% CI 0.13-0.58) without increasing the risk of infection, seroma, or hematoma formation, compared with sutured repair [96].
●All ventral hernias – A 2017 meta-analysis of 25 randomized controlled trials in ventral hernia repair concluded that mesh reinforcement in clean cases can decrease hernia recurrence (number needed to treat = 7.9) but increase risk of surgical site infection (number needed to harm = 27.8) [97].
Mesh material — The three general categories of mesh used in the repair of ventral hernias are synthetic mesh, biologic mesh, and biosynthetic mesh. (See "Reconstructive materials used in surgery: Classification and host response".)
●Synthetic – Synthetic meshes are either woven from an extruded monofilament (eg, polypropylene or polyester) or created from expanded polytetrafluoroethylene (ePTFE) and can be subcategorized by weight/density (ultra-lightweight to super-heavy weight) as well as by material; composition; pore characteristics; and mechanical parameters, including tensile and burst strength, elasticity, and stiffness [98,99]. (See "Reconstructive materials used in surgery: Classification and host response", section on 'Synthetic materials'.)
For elective ventral hernia repair, lightweight meshes generally should not be used; although a lightweight mesh was associated with less postoperative pain than medium-weight mesh [100], it was also associated with a higher rate of hernia recurrence [86]. Some studies favored medium-weight mesh to light- or ultra-heavy-weight meshes [101], although a randomized trial found similar clinical outcomes between medium-weight and heavy-weight polypropylene mesh in open retromuscular ventral hernia repair [102].
●Biologic – A variety of biologic meshes derived from human or animal tissues (eg, porcine, bovine, equine) are also available for abdominal wall reconstruction [103]. Biologic tissue is rendered nonimmunogenic by a washing process that is designed to remove cellular debris without damaging the connective tissue scaffold, which functions as an acellular biologic matrix into which the recipient's native tissue grows, eventually replacing it [103]. (See "Reconstructive materials used in surgery: Classification and host response", section on 'Allograft processing' and "Reconstructive materials used in surgery: Classification and host response", section on 'Xenograft processing'.)
We suggest that the primary setting for using biologic mesh materials be a contaminated or infected operative field or patients at high risk for surgical site infection [104]. However, others have reported equivalent or better outcomes utilizing synthetic mesh in clean-contaminated or contaminated fields [12,105-107]. As an example, in the contaminated subgroup analysis of the PRICE trial, the polypropylene mesh group had a lower rate of hernia recurrence at two years versus the porcine biologic mesh group (5.9 versus 50 percent; p for interaction = 0.041), while the two groups had similar postoperative complication rates [10]. Similarly, in another randomized clinical trial that followed 253 patients for two years after an open retromuscular ventral hernia repair in a clean-contaminated or contaminated field, the synthetic mesh group had a lower rate of hernia recurrences than the biologic mesh group (5.6 versus 20.5 percent), while the two groups had similar rates of surgical site occurrences requiring another procedure (including infectious complications) and similar quality-of-life outcomes [108]. The cost of the biologic mesh was 200 times that of the synthetic mesh. Given the increased cost of biologic mesh, these results support the use of synthetic mesh over biologic mesh in CDC II/III cases. That said, surgeons should be well aware of the specific context in which these cases were done: open, nonemergency cases, with retromuscular mesh placement and fascial closure, done by surgeons who perform retromuscular repairs at a high volume. Often, if surgeons are not comfortable with a retromuscular repair, the question should not be what kind of mesh to use but whether or not a concomitant repair should be done at all. In many contaminated scenarios (eg, bowel resection, stoma reversal, cholecystectomy), the hernia should be primarily repaired, to be followed by a staged mesh repair in a clean setting.
We suggest using biologic mesh only as a reinforcing layer, rather than as a fascial replacement [109,110]. Because biologic mesh gradually resorbs over time, bridged repairs with biologic or bioabsorbable mesh are associated with high rates of recurrence [107,111-113]. As an example, in the LAPSIS trial, 253 patients with an abdominal wall hernia of 4 to 10 cm underwent repair with synthetic or biologic (Surgisis) mesh [11]. Compared with synthetic mesh, biologic mesh resulted in more major complications after both open (23 versus 10 percent) and laparoscopic repair (27 versus 11 percent). This trial was terminated prematurely due to a very high rate of hernia recurrence after biologic mesh repair, especially laparoscopically (23 versus 3 percent synthetic mesh).
●Biosynthetic – Long-acting resorbable meshes are synthetically derived products with resorption profiles between 6 and 36 months. This time frame theoretically allows for native collagen deposition to account for wound strength and durability without the concern of chronic mesh infection often affiliated with permanent synthetic alternatives. Clinical data exist for three long-acting resorbable synthetics: TigrMatrix (TM), Gore Bio-A, and Phasix [114].
•TM is made of several polymers that begin degrading at 14 days but are not fully resorbed until 36 months [115]. Clinical data for TM are limited to only two small series published. One reports its use in 40 open inguinal hernia repairs with a three-year recurrence rate of 20 percent, 16 percent incidence of chronic pain, and 10 percent incidence of mesh sensation [116]. The other series included 16 patients at high risk for fascial dehiscence with TM placed as an onlay. No fascial dehiscences occurred [117]. Given the paucity of clinical data available, the performance of TM in the context of ventral hernia repair is unknown.
•Gore Bio-A is a copolymer of poly(glycolide:trimethylene carbonate) that is fully resorbed by six months. Prospective clinical data exist from the Complex Open Bioabsorbable Reconstruction of the Abdominal Wall (COBRA) study, which included 104 ventral hernia repairs >9 cm2 in a contaminated setting (Centers for Disease Control [CDC] surgical wound class II to IV (table 1)) [105]. While two-thirds of patients required a component separation, all patients achieved fascial closure with mesh in the retromuscular (90 percent) or intraperitoneal (10 percent) position. With 84 percent follow-up at two years, 17 percent of patients had a recurrence. While there was no comparator arm, these data suggest that use of Bio-A in a contaminated setting is safe with reasonable outcomes. Bio-A is unique in that the COBRA trial included the use of Bio-A in cases where infected mesh was removed and could be classified as CDC wound class IV.
•Phasix is a naturally derived monofilament poly-4-hydroxybutyrate (P4HB) polymer produced by Escherichia coli K12 bacteria through transgenic fermentation techniques and is fully resorbed at 12 to 18 months [118]. One study prospectively studied 120 ventral hernia repairs >10 cm2 in patients with "high-risk" medical comorbidities. At 18 months, 79 percent of patients had a 9 percent recurrence rate [119]. At three years, 68 percent of patients in the initial trial had an 18 percent recurrence rate [120]. While these outcomes demonstrate the safety of Phasix with acceptable outcomes, they were achieved in clean cases (CDC class I) and must ultimately be compared with permanent synthetic meshes more commonly used in this setting.
To address the heterogeneous cohorts in these studies and account for the absence of a control arm in either prospective trial for Bio-A and Phasix, an Abdominal Core Health Quality Collaborative (ACHQC) analysis was done to compare propensity-matched groups of long-acting resorbable and polypropylene mesh ventral hernia repairs in CDC class II/III wounds. Interestingly, biosynthetic mesh repairs had higher rates of surgical site infections (22 versus 11 percent, p = 0.03), surgical site occurrences requiring a procedural intervention (24 versus 13 percent, p = 0.049), and reoperation rates (14 versus 4 percent, p = 0.009) than polypropylene mesh repair [121]. As a class, biosynthetic mesh has not been compared against synthetic mesh in any randomized trial.
●Choosing a mesh by wound classification – When available, the choice of a hernia mesh is primarily determined by the surgical wound classification (table 1) as follows.
•For clean wounds (CDC surgical wound class I), our preference is to use synthetic mesh despite the presence of "high-risk" medical comorbidities, as there is no evidence to suggest that biologic or biosynthetic mesh performs better in this context [10,11].
•For clean-contaminated or contaminated wounds (CDC surgical wound class II/III), despite mounting evidence that supports the nuanced use of synthetic mesh [11,12], high-level evidence to guide decision making is limited, and therefore use of a biologic or biosynthetic mesh in this setting would be viewed as reasonable by most surgeons [122].
•For dirty infected wounds (CDC surgical wound class IV), primary closure and planned "staged" repair is safe and often the wise decision [123]. While no mesh has an indication in a contaminated setting, Bio-A (biosynthetic) has prospective data available demonstrating its safety in CDC class IV wounds (including concomitant excision of infected mesh) at the time of ventral hernia repair. Alternatively, a biosynthetic or biologic mesh can be used.
Mesh location — The mesh can be placed above the fascia (onlay), between the rectus muscles and peritoneum/posterior rectus sheath (sublay), below the peritoneum (underlay or intraperitoneal onlay), or in between fascial edges (inlay) (figure 2) [124]. The onlay and sublay techniques use an open or robotic surgical approach, whereas an underlay technique can be performed open, laparoscopically, or robotically. The inlay technique, which bridges the fascial defect with mesh, is used only when the fascial defect is too large to primarily close with any other techniques.
For open hernia repair, we prefer sublay placement of the mesh to an onlay technique. For laparoscopic repairs, we place the mesh in an underlay position. For robotic repair, the mesh is placed in either any sublay or underlay position depending on the technique used. A systematic review of 62 studies, which included two randomized trials [86,97,125], showed that both the recurrence and complication rates were higher with onlay or inlay meshes than with sublay or underlay meshes (table 2) [126].
Hernia meshes are commercially available as either flat sheets or "patches" designed to ease placement or fixation. In a randomized trial of 352 patients with a primary small umbilical or epigastric hernia, repair with a flat polypropylene mesh in the preperitoneal location resulted in fewer complications (22 versus 33 percent) and reoperations (4 versus 11 percent) than repair with a Proceed ventral patch [38]. There was no difference in hernia recurrences. However, this trial has been criticized for a high loss to follow-up and possible issues with the Proceed patch.
●Onlay – With the onlay technique, the hernia sac is dissected and either inverted or resected. The fascial edges are approximated with sutures in a fashion similar to that of a simple suture repair. Thereafter, a piece of mesh is placed anterior to the fascia overlying the repair and affixed to the anterior abdominal wall fascia using sutures (our preference), tacks, or adhesives.
Although onlay mesh placement was historically associated with a high wound complication rate, it is technically easier to perform than the other techniques and is possible to perform without entering the peritoneum. The onlay technique pioneered by Chevrel [127] is again gaining popularity, especially in European countries [128,129]. In a contemporary case-matched study in low-risk patients, patients who underwent ventral hernia repair with onlay mesh affixed with bioadhesive did not have more wound complications than matched patients who had sublay mesh placed [130]. However, onlay repair has been associated with increased risk of wound complications based on existing randomized trials [97].
●Sublay (retrorectus) – Sublay mesh repair of ventral hernias can be performed with an open or robotic approach. The open technique, first described by Rives and Stoppa and bearing their names, involves first isolating and excising the hernia sac. The plane between the posterior rectus sheath and rectus muscle is developed and carried to the lateralmost extent of the rectus muscle to completely mobilize the posterior sheath, which is then sutured to the opposing sheath, and a large sheet of mesh is placed anterior to the posterior rectus sheath and posterior to the rectus muscle. Sutures are passed through the lateral abdominal wall and tied above the anterior fascia with the knots buried in the subcutaneous tissue. Depending upon the amount of tension encountered, the anterior rectus sheaths can be reapproximated and sutured together in the midline or sutured to the mesh. (See "Open posterior component separation techniques", section on 'Rives-Stoppa retrorectus dissection' and "Robotic component separation techniques", section on 'Robotic Rives-Stoppa retrorectus dissection'.)
●Underlay (IPOM) – The underlay method, also referred to as the intraperitoneal onlay mesh (IPOM) method, places the mesh in an underlay or intraperitoneal location. If an underlay mesh is placed via the open approach, most surgeons either suture the mesh to the posterior sheath/peritoneum or use a suture passer to place transfascial sutures. The anterior fascial sheath is then closed over the mesh. Laparoscopic ventral hernia repair typically involves placement of a mesh in an underlay position. (See "Laparoscopic ventral hernia repair".)
Mesh size — The mesh used for ventral hernia repair should be sufficiently large to permit >2 cm overlap for open repair of small primary ventral hernias (<1 cm in diameter), >3 cm overlap for open repair of medium primary ventral hernias (1 to 4 cm in diameter), >5 cm overlap for open repair of large primary ventral hernias (>4 cm in diameter) or ventral incisional hernias [34], and >5 cm overlap for all laparoscopic repairs [131]. For laparoscopic repair, other guidelines suggest that the radius of the mesh should be four times the radius of the fascial defect being addressed [81,132].
SPECIAL POPULATIONS
Obesity — Obesity is a major risk factor for ventral hernia development. According to the consensus guidelines on bariatric surgery and hernia surgery from the American Society for Metabolic and Bariatric Surgery and the American Hernia Society [133]:
●For patients with severe obesity and ventral hernia, both of which are amenable to laparoscopic repair, combined hernia repair and bariatric surgery may be safe and associated with good short-term outcomes and low risk of infection.
●For patients with severe obesity and ventral hernia that is not amenable to laparoscopic repair, a staged approach is recommended, beginning with bariatric surgery [134].
Pregnancy — Pregnant women should only undergo surgical repair of a highly symptomatic hernia or for complications such as acute incarceration or strangulation. There have been reports of successful laparoscopic ventral hernia repair during pregnancy [135].
Asymptomatic or minimally symptomatic ventral hernia repairs should be delayed until after delivery [135]. It is controversial whether symptomatic ventral hernias diagnosed during pregnancy should be repaired at the time of a cesarean section [8,136].
Although laparoscopic ventral hernia repair causes no significant problems with pregnancy or delivery in those who become pregnant again after the repair [137], it may be associated with hernia recurrences [138,139] and pain during pregnancy, especially during the third trimester [136]. For those reasons, some authors suggest the optimal timing of elective repair is after the last pregnancy.
Cirrhosis — Patients with cirrhosis are prone to developing abdominal wall hernias due to increased intra-abdominal pressure (from ascites) and impaired healing (due to poor synthetic function and nutrition). Nonoperative management of ventral hernias in patients with cirrhosis is more likely to fail than in patients without cirrhosis. In a small randomized trial, 77 percent of patients initially assigned to nonoperative management suffered a complication related to the hernia or hernia repair at two years [140].
The indications and optimal timing for ventral hernia repair (most commonly umbilical hernia) in patients with cirrhosis, however, are controversial. Most surgeons advocate elective repair of symptomatic ventral hernias after medical optimization (ie, control of ascites and management of portal hypertension) to avoid the high morbidity and mortality expected of an emergency repair [141,142]. Synthetic mesh is safe to use in patients with cirrhosis [143]. A few authors have suggested that the routine use of peritoneal dialysis catheters in patients with refractory ascites at the time of hernia repair reduces complication rates [144]. However, the long-term presence of indwelling catheters may lead to intra-abdominal infections [145]. Patients with planned liver transplantation should have their hernias repaired at the time of the transplantation, unless they develop one of the complications before transplantation.
The optimal surgical approach for ventral hernia in patients with cirrhosis is also debated. An analysis of patients with Model for End-stage Liver Disease (MELD) score ≥9 who underwent elective ventral hernia repair in the National Surgical Quality Improvement Program Database revealed that only 15 percent of the repairs were performed laparoscopically. Although laparoscopic repair was associated with superior outcomes compared with those of open repair (eg, shorter length of stay, fewer wound complications, lower mortality rate), there was selection bias against open repairs. In a planned subgroup analysis of patients with ascites, laparoscopic ventral hernia repair was associated with higher perioperative mortality, more systemic complications (eg, septic or renal), and more unplanned reoperations [146].
Anatomically difficult hernia locations — These hernias are difficult to repair because their proximity to bony prominences makes mesh fixation complicated.
Suprapubic hernia — Suprapubic ventral hernias are an uncommon type of incisional hernia (0.5 to 2 percent) typically associated with trocar placement, suprapubic catheters, and/or low transverse or midline surgical incisions. They typically occur within 4 to 5 cm of the pubic arch. Successful repair requires some degree of preperitoneal dissection to allow for mesh fixation to Cooper's ligament and the pubic arch. To facilitate preperitoneal dissection, patients should be placed in the Trendelenburg positioning and a Foley catheter inserted to decompress the bladder [147-151]. Surgeons considering laparoscopic repair of suprapubic hernias should have familiarity with laparoscopic inguinal and femoral hernia repair. (See "Laparoscopic inguinal and femoral hernia repair in adults".)
Subxiphoid hernia — Subxiphoid hernias occur in 4 percent of patients after sternotomy [152]. The specific challenge in this group of patients is attaining sufficient mesh overlap in the proximity of the xyphoid process. Laparoscopically, surgeons should avoid using tack above the costal margin to prevent injury to thoracic structures such as the pericardium [153]. Some have described no fixation, adhesives, or intracorporeal sutures as an alternative. Retrospective data suggest lower recurrence rates with open preperitoneal repair, possibly attributable to better fascial closure and mesh placement anterior to preperitoneal fat [154].
Lateral hernias — According to the European Hernia Society classification system, lateral abdominal wall hernias are defined to lie lateral to the rectus sheath and are classified into subcostal, flank, iliac, and lumbar hernias (figure 3). The surgical repair of such hernias is discussed in another topic. (See "Lateral abdominal wall hernia repair".)
HERNIA RECURRENCE — Ventral hernia recurrence is typically diagnosed at a clinical encounter; certain patient-reported outcomes (eg, bulge or pain at the repair site) can help detect long-term recurrences [155]. The cause of recurrence is multifactorial and may include mesh fracture, improperly placed or fixated mesh that pulls away from the fascial edge, unrecognized hernia near the site of the repair, obesity, or subsequent surgery.
Rates of recurrent hernia depend upon the size of the hernia and type of repair and the definition and method of hernia detection but are known to increase with each additional hernia repair that is performed. As examples:
●In one retrospective study of 794 abdominal wall hernia repairs, recurrence rates at over 10 years postoperatively were 37, 64, and 73 percent after the primary, incisional, and multi-incisional hernia repairs, respectively [156].
●A retrospective study of over 10,000 patients undergoing ventral hernia repair between 1987 and 1999 reported a five-year reoperation rate of 12 percent and a 13 year reoperation rate of 23 percent. The five-year reoperative rate was 24 percent after the first reoperation, 35 percent after the second, and 39 percent after the third [157].
●Another retrospective study of over 175,000 patients undergoing ventral, incisional, or umbilical hernia repair between 2008 and 2017 reported a 10 year cumulative incidence of reoperation for recurrence of 16.1 percent (95% CI 16.1 to 16.2 percent) for ventral hernia and 12.3 percent (95% CI 12.2 to 12.3 percent) for umbilical hernia. The reoperation rate was slightly higher for minimally invasive than open repair for both ventral and umbilical hernias [158]. The reoperation rate is an underestimate of recurrence rate.
In patients with recurrent incisional hernias, the repair can be repeated by excising and replacing the damaged mesh using an open or laparoscopic approach that is individualized based upon the extent of the prior dissection and the size and location of the defect [57,81]. Because of the high recurrence rates seen with redo incisional hernia repairs, these hernias should be repaired with adjunctive techniques, such as mesh implantation and/or component separation, in an attempt to break the vicious cycle of complications (recurrence followed by reoperation followed by another recurrence caused by complications) [156].
A retrospective review of 3028 recurrent ventral hernia repairs from a single institution compared suture repair (n = 2383) with an adaptation of component separation technique (n = 645) over a mean follow-up of 5.5 years [159]. Only the midline anterior rectus sheath was reinforced with an onlay mesh in the component separation group. The failure rate (re-recurrence) following suture repair was 38 percent, whereas it was 18.3 percent following component separation repair. Significant risk factors for re-recurrence included obesity, age greater than 65 years, male sex, postoperative seroma, and preoperative infection. There was no significant association between the type of mesh used and re-recurrence.
MORBIDITY AND MORTALITY — Morbidity and mortality following repair of ventral hernias are overall low in appropriately selected surgical candidates.
The incidence of wound infection is approximately 5 percent for open repairs and may be slightly lower for laparoscopic repairs [56]. Between 1.4 and 6.9 percent of meshes had to be removed because of infection [160-162]. Risk factors associated with mesh explantation include enterotomy or another abdominal procedure concomitant with the hernia repair, surgical site infection, and onlay position of mesh placement [160]. In a large administrative database study of over 600,000 patients who underwent at least one ventral hernia repair, 0.07 percent had mesh removed after a median of 346 days after initial surgery [163]. The median cumulative cost for patients who required mesh explantation was substantially higher than for those who did not require mesh removal ($21,889 versus $6983). (See "Wound infection following repair of abdominal wall hernia".)
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Ventral hernia" and "Society guideline links: Abdominal compartment syndrome".)
SUMMARY AND RECOMMENDATIONS
●Terminology – Ventral hernias occur in the anterior abdominal wall and include epigastric, umbilical, Spigelian, parastomal, and most incisional hernias. Epigastric and umbilical hernias are primary ventral hernias. Incisional hernias can develop anywhere an incision has been made but most commonly at the midline, given that midline incisions are most commonly used during laparotomies. Spigelian, lumbar, and parastomal hernias occur off the midline. (See 'Introduction' above.)
●Acutely incarcerated or strangulated ventral hernias – For patients with an acutely incarcerated or strangulated ventral hernia, we suggest an urgent open, rather than laparoscopic or robotic, repair (Grade 2C). The objectives of an urgent surgery are to alleviate any acute problems (eg, bowel infarction, bowel obstruction, abdominal pain) and perform the safest and most durable repair given the clinical setting. (See 'Acutely incarcerated or strangulated ventral hernias' above.)
●Reducible or chronically incarcerated ventral hernias
•Asymptomatic – Asymptomatic and minimally symptomatic ventral hernias can be managed expectantly if patients wish to avoid surgical repair. (See 'Asymptomatic ventral hernias' above.)
•Symptomatic – Surgical repair is indicated for patients with a symptomatic ventral hernia. However, patients who smoke, have severe obesity (body mass index >50 kg/m2), or have poorly controlled diabetes (with an HbA1c >8 percent) should undergo preoperative optimization before they are offered an elective surgery (algorithm 1). (See 'Symptomatic ventral hernias' above.)
●Ventral hernia repair approaches – Ventral hernias can be repaired with sutures, mesh, or component separation depending on hernia etiology (primary versus incisional), width, and surgeon expertise/preference (algorithm 1) (see 'Surgical management of ventral hernias' above):
•Primary ventral hernia <1 cm – For small (<1 cm) primary ventral (eg, mostly umbilical, some epigastric) hernias, we suggest open repair with sutures with or without mesh reinforcement (Grade 2C). Minimally invasive mesh repair is also reasonable.
•Incisional ventral hernia <1 cm – Small incisional hernias often arise at trocar sites of a previous laparoscopic surgery. For all incisional ventral hernias, we suggest mesh repair, including those that are <1 cm (Grade 2C). Such small hernias can be repaired open or minimally invasively.
•All ventral hernia 1 to 10 cm – For all ventral hernias between 1 and 10 cm, we suggest a mesh rather than suture repair (Grade 2B). Simple suture repair is associated with a high recurrence rate.
-All ventral hernias 1 to 4 cm – For small umbilical and epigastric hernias in thin patients, we perform open mesh repair. For patients with obesity or other risks for wound infection, and patients with significant upper abdominal diastasis recti bordering the hernia defect, we perform minimally invasive mesh repair.
-All ventral hernias 4 to 10 cm – For all ventral hernias between 4 and 10 cm, we recommend minimally invasive repair with mesh rather than open repair with mesh (Grade 1B). Minimally invasive repair is associated with lower incidences of surgical site and mesh infection, less pain, and faster recovery.
•All ventral hernias >10 cm – Large (width >10 cm) or complex ventral hernia repair typically requires advanced techniques (eg, component separation) as primary fascial closure is unlikely to be achieved without them. Component separation is typically performed with mesh reinforcement. (See 'Large (width >10 cm) or complex hernias' above.)
●Mesh material (see 'Mesh material' above):
•Clean wound – For most ventral hernia repairs in a clean wound (Centers for Disease Control [CDC] surgical wound class I), we suggest using a synthetic mesh rather than another type of mesh (Grade 2C).
•Clean-contaminated or contaminated wound – For most ventral hernia repairs in a clean-contaminated or contaminated wound (CDC surgical wound class II/III), synthetic, biologic, and biosynthetic mesh have all demonstrated acceptable outcomes. Surgeons apprehensive about chronic mesh infection can use biologic or biosynthetic mesh. Biologic meshes should only be used as a reinforcing layer, rather than as a fascial replacement, to avoid high recurrence rates.
•Dirty infected wound – Ventral hernia repair in a dirty, infected wound (CDC surgical wound class IV) is not standardized. Most often these cases are staged first with a primary repair followed by a subsequent mesh repair in a lower wound class. Alternatively, a biosynthetic or biologic mesh can be used.
●Mesh location – For open ventral hernia repair, we suggest sublay mesh placement rather than another mesh location (Grade 2C). For laparoscopic repair, we suggest intraperitoneal mesh placement rather than another mesh location (Grade 2C). Robotic repair places mesh at either the sublay or intraperitoneal location, depending on technique. (See 'Mesh location' above.)
●Mesh size – The mesh used for ventral hernia repair should be sufficiently large to permit >2 cm overlap for open repair of small primary ventral hernias (<1 cm in diameter), >3 cm overlap for open repair of medium primary ventral hernias (1 to 4 cm in diameter), >5 cm overlap for open repair of large primary ventral hernias (>4 cm in diameter) or ventral incisional hernias, and >5 cm overlap for all laparoscopic repairs. (See 'Mesh size' above.)
ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges John Cone, MD, who contributed to an earlier version of this topic review.
