An ideal mesh has sufficient strength, is chemically stable, is easily sterilized, resists infection, is non-carcinogenic, limits inflammatory foreign body reactions, and incorporates (heals) well into the abdominal wall[22]. The latter point is important as many ventral hernia recurrences occur at the interface of the mesh and the wounded abdominal wall, a form of acute wound failure[23,24]. Materials fitting these prerequisites were not developed until the 1900s. Silver was used first, followed by stainless steel and other metals[22]. Polypropylene mesh was not created until 1959. Since then, several categories have been produced: Non-absorbable synthetic meshes, composite meshes, absorbable meshes and tissue-based biologic implants.

Permanent meshes, such as polypropylene and polyester, were use when laparoscopic hernia repairs were first started. However, uncoated meshes were soon abandoned due to the large number of visceral adhesion related complications, such as fistula, bowel obstruction, and complications during re-operative adhesiolysis[24]. Table 1 summarizes some of the main advantages and disadvantages of these meshes.

Composite meshes were developed for laparoscopic intraperitoneal onlay placement, and are the ones usually used for laparoscopic hernia repair[24]. They combine the strength of permanent mesh with a bowel-protective anti-adhesion barrier. The parietal peritoneum side is composed of permanent mesh, usually polypropylene or polyester, which provides structural strength and promotes tissue inflammation and ingrowth. The visceral facing side of the mesh requires an anti-adhesion barrier. Most of these barriers are absorbable, with the exception of expanded polytetrafluoroethylene[25]. Table 2 provides a general overview of the most common composite meshes used for laparoscopic ventral and incisional hernia repair and relevant research. Unfortunately, there is a lack of high-level clinical evidence to direct surgeons and patients as to the safest and most effective material.

New meshes are being developed for potential use in laparoscopic ventral and incisional hernia repair (Table 3). Recently, absorbable synthetic meshes were developed to have a better infection resistance profile, but risk recurrence by weakening during the resorption process[37]. To date, at least 3 new, slow resorbing meshes have been developed, including BioA^® tissue reinforcement by Gore^®, TIGR^® Matrix by Novus Scientific[38], and Phasix™ mesh by Bard[39]. These meshes might be used for laparoscopic repair in contaminated fields, including parastomal hernia repair.

Titanized mesh might help reduce inflammatory, foreign body reactions and reduce pain after laparoscopic repair, although results have yet to be confirmed in randomized or comparative studies[42]. A third kind of mesh helps prevent migration and reduces the amount of mesh fixation needed. Covidien created a new, self-gripping mesh currently being used in laparoscopic inguinal, as well as open ventral and incisional hernia repairs. ProGrip™ is a polyethylene mesh that includes small absorbable “hooks” designed to promote abdominal wall adhesion, prevent migration, and decrease the number of fixation points needed. One study asserts less postoperative pain after inguinal hernia repair, but this has not been observed in other studies[43,44]. This mesh might be used in order to decrease the number of tacks and sutures needed for fixation.

Laparoscopic lysis of adhesions is performed prior to mesh placement. Multiple instruments exist for this application, including newly developed ultrasonic shears and bipolar devices. However, there is currently no level I data on the superiority of one over the other. Intraperitoneal mesh is placed once the hernia defect is identified and prepared, and there are many variations in the fixation of that mesh. Most surgeons cover the hernia defect with a 3 to 5 cm overlap circumferentially, and then secure the mesh in place with transfascial sutures and/or intra-abdominal peritoneal tacking[8,11]. Little is known about the physiologic movement of mesh in vivo during physiologic stress, however, the ideal technique would prevent migration and folding of the mesh[45].

Over the years, surgeons have varied greatly in the number of tacks, the number of sutures, as well as the materials of tacks and sutures used for fixation[46]. The goal has been to balance adequate fixation to prevent recurrence against excessive fixation that can lead to unnecessary pain. It is also important to minimize the amount of permanent component of mesh without sacrificing overlap, because large meshes require multiple, potentially painful fixation points, and have an increased risk of chronic pain from foreign body reaction[47]. The use of transfascial sutures may allow the surgeon to limit overlap to only 3 cm, whereas the use of tacks requires at least 5 cm of overlap[48]. An intuitive understanding of biomechanical forces suggests that transfascial sutures provide better fixation, as they are secured to the strong anterior fascia. Unfortunately, transfascial sutures risk abdominal wall nerve entrapment and muscle strangulation, which is thought to contribute to the significant postoperative pain[46]. Tacks provide a 3.8 to 6.8 mm posterior to anterior purchase of the abdominal wall and do not capture the anterior fascia[49]. The tensile strength of sutures was 2.5 times greater than that of tacks in a pig cadaver model; however, a laparoscopic pig model showed no signs of migration or recurrence, and no additional fixation strength at 4 wk when only tacks were used[46]. More tacks are used than suture, and increasing the number of tacks theoretically cause more pain. Schoenmaeckers et al[50] demonstrated that decreasing the average number of tacks to 20 from 40 significantly decreases their visual pain analog scale at 3 mo from 5.8 to 1.8 out of 100 (P = 0.002), which is not likely to be clinically significant. Of note, this study did not control for the type of mesh.

Recently absorbable tacks have been developed, with the objective of reducing pain, foreign body reactions, and adhesion formation. One porcine model proved similar tensile fixation strength between a 4.1 mm poly (glycolide-co-L-lactide) tacks and a control titanium tacks at 6 mo and less tensile strength with 6.8 mm poly (D,L)-lactide tacks[49].

Many studies compare sutures vs spiral tackers; however, many of these studies do not adequately control for patient demographics, hernia size, technical variations, suture type, and mesh size and type, to name a few. Multiple reviews largely showed no optimal technique to prevent recurrence and reduce pain. A recent systematic review by Reynvoet et al[46] grouped 25 prospective and retrospective studies from 1999 to 2011 into suture only repair, tack only repair, and both sutures and tacks. Other reviews included many of the same studies, however, this study used the DerSimonian-Laird random effects model to assign relative weights in relation to study sample size. The hernia recurrence rate for the suture only group (0.9%CI: 0%-1.7%) was less than the tacks only group (3.4%CI: 2.4%-4.5%) and the combination of suture and tack group (2.5%CI: 1.3%-3.7%). As the CIs were overlapping, there was no significant difference in recurrence rate between the three fixation techniques. This is consistent with other past reviews[46,48,51].

The review by Reynvoet et al[46] was unable to statistically analyze the outcome of pain following hernia repair, as there was not a standardized way between studies to report pain outcomes. Chronic pain was defined as pain anywhere from 4 wk to 6 mo. Narcotic use, pain analog scales, and quality of life surveys measured pain threshold. Despite these methodological variations between individual studies, Reynvoet et al[46] concluded that literature currently shows no significant difference in postoperative pain between suture and tack repairs.

In contrast, the WoW trial (with or without sutures), a randomized controlled trial from Belgium, showed significantly more pain with “sutures and tackers”vs a “double crown” tack arrangement[52]. Patients were asked to draw a line representing postoperative pain; significant pain was defined as a visual analog scale score greater than 1 cm. There was a significant difference at 4 h when coughing, and 3 mo at rest (31.4% vs 8.3%, P = 0.036). Secondary outcomes were reported, showing less operative time in the tacks only group and similar hernia recurrence at 24 mo. However, the main limitation was the somewhat arbitrary 1 cm visual analog scale for pain (VAS) cutoff for significant. A similar study by Wassenaar et al[53] used VAS mean scores instead of the 1 cm cutoff. It showed no difference between double crown tackers, absorbable suture and tackers, and non-absorbable suture and tackers.

New less invasive, less painful alternatives for mesh fixation have been developed for hernia repair. Fibrin sealant initially was used for inguinal hernia repair; however, it has also been studied for laparoscopic incisional repair[54]. In 2011, a randomized prospective study was performed comparing the use of fibrin sealant only to the use of titanium tacks only after laparoscopic umbilical hernia repair[55]. At 4 wk follow-up, there was significantly less acute postoperative pain both at rest and during activity, as well as shorter convalescence (median 7 d vs 18 d, P = 0.027) with use of fibrin sealant. At 1-year follow-up, these differences were not significant, and the hernia recurrence rate was predictably higher in the fibrin only group, though statistically insignificant (26% vs 6%, P = 0.18). Another study used fibrin sealant in the hernia sac after laparoscopic hernia reduction[56]. This showed a significant reduction in the incidence of seromas at 1 mo (72% control vs 28% with sealant, P = 0.002). Although promising for some limited applications, the current data does not show an advantage to routine use of fibrin sealant, and shows a trend toward increased recurrence rates if it is used alone for mesh fixation.

Once the hernia contents are reduced, the defect is measured and prepared for mesh placement[11]. Traditionally, a tension free repair is created by placing mesh over the defect and securing it in place. Some surgeons prefer to close the hernia defect primarily prior to this step. Three main laparoscopic approaches have been described: (1) interrupted percutaneous closure with suture passer; (2) intra-corporeal suturing; or (3) Endo Stitch^TM suturing with a knot pusher[13]. Barbed suture can be used for defect closure or mesh fixation in order to decrease the tension needed when placing each suture. Lyons et al[57] used a porcine model to show that barbed suture requires the application of 75% less force than conventional suture, while maintaining adequate mesh fixation strength.

There are many proposed advantages of performing primary defect closure before applying the mesh[13,58]. Re-approximating the abdominal fascia is thought to be a more physiologic repair, and thus stronger. Additionally, it provides a greater surface area of abdominal wall for the mesh to be in contact with. Furthermore, it prevents postoperative bulging of the mesh into the defect. Bulging is not ideal for cosmesis, and may allow mesh to come closer to the skin surface, which can increase the risk of mesh infection and erosion. Conversely, closing the defect increases tension, which may be counterproductive. Also, placement of extra suture in the abdominal wall increases the risk of postoperative pain. Many surgeons have yet to adopt this technique, most likely due to the technical difficulty, and the current lack of evidence suggesting its superiority when compared to mesh placement alone.

Current literature lacks randomized control trials examining the effectiveness of concomitant primary defect closure during laparoscopic ventral and incisional hernia repair. Nguyen et al[58] performed a systematic review of 11 studies, including case series and retrospective reviews. Recurrence rate ranged from 0% to 7.7%, and seroma rates were 0% to 11.4%. Three of the retrospective reviews included compared laparoscopic hernia repairs with and without primary defect closure. Clapp et al[59] was the only risk adjusted study and followed 72 cases for an average of 24 mo. Hernia recurrence was 16.7% in the group without primary defect closure, whereas no recurrences were seen in the group with primary defect closure. Bulging in this study was decreased from 69.4% in the non-closure group to 8.3% in the closure group. In addition, superficial wound infections were decreased from 13.9% to 8.3%, and the incidence of seroma was decreased from 27.8% to 5.6%. Another retrospective comparative review of 128 patients also reported low recurrence rates after concomitant primary defect closure (6.25%), but this was not significantly different when compared to the group without primary defect closure[13]. Interestingly, the incidence of seroma formation was higher in the group with primary defect closure than the group without primary defect closure (11.4% vs 4.3%).

The separation of components technique includes various methods of dissecting the abdominal wall layers in order to advance facial edges and decrease physiologic tension. In 1990, Ramirez et al[60] first described releasing the external oblique aponeurosis alone, which allows approximately 5 cm of unilateral fascia advancement at the umbilicus, and 3 cm inferiorly and superiorly. The drawback is that it weakens the abdominal wall, especially laterally at the semilunar line[61]. In 2000, Lowe et al[62] combined an open technique with balloon dissection endoscopy. A few years later, Rosen et al[63] began separating the external and internal oblique muscles laparoscopically, followed by release of the external oblique aponeurosis. In the morbidly obese population, the presence of thick subcutaneous tissue can make this last technique challenging. After laparoscopic myofascial release, the overlying attached subcutaneous tissue limits movement of that fascia toward the midline[64]. This restricts the advancement to 86% of that of the open release[63].

Although minimally invasive separation of components provides less myofascial release, it avoids creating large skin flaps and spares vital perforating vessels[61,64]. On the other hand, open technique allows excision of dystrophic and tissue expanded skin in conjunction with the hernia sac. One could assume that subsequent advancement of normal skin into the wound may lead to better wound healing and cosmetic result. However, recent studies note a decrease in wound complications with the minimally invasive approach, without significantly affecting recurrence rates[64]. A systematic review comparing minimally invasive component separation with open component separation included 7 non-randomized controlled studies and 56 case series with a total of 3055 patients[61]. Minimally invasive component separation as compared to open component separation resulted in lower rates of total complications (20.6% vs 34.6%), superficial wound infection (3.5% vs 8.9%), necrosis (2.1% vs 6.8%), and hematoma/seroma (4.6 % vs 7.4%). Open component separation had a lower rate of recurrence (11.1% vs 15.1%), possibly due to a higher rate of simultaneous midline mesh repair in this group. They went on to perform a meta-analysis of the 7 non-randomized controlled studies, which included 387 patients. This showed a significant decrease in skin dehiscence (OR = 3.18) favoring minimally invasive component separation.

Most studies use variations of the Rosen anterior release technique. Posterior component release techniques have also been described, most notably the transversus abdominis muscle release[65]. This involves dissection in the retrorectus space to the semilunar line. The transversus abdominis muscle is then divided vertically that allows entry to the preperitoneal space below, dissection is carried laterally, and a mesh is placed as a sublay. This dissection is tedious and theoretically carries higher risk with a wider learning curve due to the presence of neurovascular structures. It is therefore rarely performed laparoscopically. However, the added dexterity of robotics make the minimally invasive technique feasible.

Ventral and incisional hernias are relatively common in patients requiring other procedures, such as cholecystectomy and bariatric procedures. Previous studies have shown a high recurrence rate and complications rate with ventral and umbilical hernia repair during bariatric procedures[66]. However, a recent retrospective review of 54 patients reported a favorable experience with laparoscopic mesh repair after gastric banding, sleeve gastrectomy, and Roux-en-y gastric bypass[67]. There were no mesh infections and only one hernia recurrence after 12 mo of follow-up. Eleven percent of patients had complications including leak, abdominal wall hematoma, and pulmonary embolism. This was consistent with expected outcomes for bariatric surgery.

Similar results were not obtained when ventral hernia repair was performed with cholecystectomy. Orr et al[68] queried the NSQIP database and found 357 cases of simultaneous cholecystectomy and ventral hernia repair. Stepwise multi-variable logistic regression analysis was performed for over 50 risk factors in the NSQIP database, comparing these to 74019 cases of cholecystectomy alone. This model determined that patients undergoing the combination procedure were 2.4 times more likely to have a wound complication, 3.1 times more likely to have sepsis or septic shock, and 2.8 times more likely to have pulmonary complications. The study was limited as it was only able to analyze 30-d outcomes. Also, it was not able to separate out which patients had mesh repair or suture repair. Nevertheless, this study gives great pause to surgeons promoting laparoscopic hernia repair during cholecystectomy.

The rate of incisional hernias due to previous laparoscopic port placement is 1% to 22%, which has stimulated interest in more advanced minimally invasive options[69]. Bucher et al[69] also reported a case series of 52 patients undergoing single port ventral and incisional hernia repair through one 10-mm endoscope with a working channel. There were no conversions to open and no morbidity, with exception of two seromas. No recurrences were noted at 16 mo. Other surgeons seek to avoid 10-mm ports altogether. Agarwal et al[70] described a technique of introducing the mesh through a port placed in the hernia defect. This obviated the need for a 10-mm port in the flank.

Natural orifice transluminal endoscopic surgery (NOTES) continues to be explored as a future option for general surgery. One case report describes repairing an umbilical port site hernia through a 2 cm incision in the posterior vaginal fornix[71]. Panait et al[72] reported a series of 107 patients undergoing transvaginal appendectomy, cholecystectomy, and ventral hernia repair. Proponents of this approach claim a potential benefit in cosmesis, decreased pain, early return to work, decreased port site complications, and specific advantages in the obese population. Most agree that NOTES operations for hernia repair increase the risk of a major complication, and these techniques should strongly be considered as experimental for now and performed under institutional research protocols.

The use of the da Vinci robot has expanded since its approval by the Food and Drug Administration in 2000[73]. Initially applied for hysterectomy and prostatectomy, it has recently been used for an increasing number of general surgery procedures, including Nissen fundoplication, single site cholecystectomy, colectomy, and ventral or incisional hernia repair. The magnified, three-dimensional high-definition view, computer-aided elimination of tremor, and seven degrees of freedom at the distal ends of the instruments with superior maneuverability, have led to its increasing adoption by several prominent surgeons[74]. In fact, LeBlanc et al[75] presented his early experiences with robotic approach at a recent American college of surgeons meeting, asserting its role in replicating open technique with minimally invasive methods.

Many surgeons are currently utilizing the robot simply to facilitate their ability to suture the hernia defect closed, and thus place the mesh as an intraperitoneal onlay. Gonzalez et al[76] compared a standard laparoscopic intraperitoneal mesh placement technique without defect closure, to a similar technique, which utilized the robot to close the hernia defect. They found an increased operative time for the robot with no difference in wound complications or recurrence. In our practice (AC-Greenville), we have developed a robotic approach to replicate the open Rives-Stoppa retromuscular incisional hernia repair technique. We are able to perform a retrorectus dissection, with or without the addition of a transversus abdominis release, or posterior component separation. We then suture the posterior rectus sheaths closed in the midline, followed by uncoated polypropylene mesh placement in the retrorectus space, and closure of the abdominal wall defect. A case controlled retrospective cohort study comparing our robotic Rives-Stoppa to the open technique favored the robotic approach with less blood loss and a shorter length of stay with no difference in operative time or direct hospital cost. Surgical site infection was 9.5% in the open group and 0% in the robotic group (P = 0.48)[77]. The sample size was small, which increased the likelihood of type II statistical error. Like any new operation, there is a steep learning curve. On the other hand, the ergonomic nature of the robotic system may allow a novice user to rapidly progress. Initially, the robotic retrorectus mesh repair with simultaneous posterior component release was taking upwards of 6 h to perform. With some technique modifications and experience, we have been able to decrease operative times into the 2.5-4 h range depending upon the degree of intraperitoneal adhesions. Interestingly, the initial cost analysis suggests that this repair is equal to open repair. Decreased cost with robotic use is not unprecedented. In fact, one study in the United States showed decreased costs with robotic single site cholecystectomy vs laparoscopic cholecystectomy ($1319 vs $1710, P = 0.001), mostly due to decreased use of supplies[78].

As the incidence of recurrence decreases, there is an increasing focus on secondary patient reported outcomes that affect postoperative quality of life. Surrogates have been created because there is no consensus on how to measure pain, mobility, cosmesis, and length of convalescence. A 2011 Cochrane review found no significant differences in acute postoperative pain (mean difference 0.09, 95%CI: -0.45 to 0.62), and return to full activity (mean difference -0.70, 95%CI: -2.10 to 0.70)[81]. One study showed no difference in acute postoperative pain, but another study showed less chronic neuralgia in the laparoscopic group. Regarding return to full activities, Pring et al[86] revealed no difference between open and laparoscopic repairs. However, Itani et al[87] found a near significant advantage for laparoscopic repair (23 d vs 28.5 d, adjusted hazard ratio 0.54, 95%CI: 0.28-1.04; P = 0.06). The Cochrane review showed a significant difference in hospital stay (mean difference -4.63, 95%CI: -5.95 to -3.32); however, this was only if the open repair control group stayed longer than 5 d[81]. There was no significant difference in quality of life (mean difference 0.44, 95%CI: -0.24 to 1.11).

In 2014, Jensen et al[88] reviewed 26 articles for quality of life assessment methods. Fifty-four percent of these used the short-form 36 (SF-36), which is a non-surgery or hernia specific scoring of general physical and mental health. The physical component focuses on pain, energy/fatigue, and functional limitations. The mental health component focuses on social functioning, emotional wellbeing, and general perception of health. Two of the studies discussed found no difference when comparing open to laparoscopic repair[87-89]. On the contrary, some other authors showed better quality of life, and better short-term physical functioning with laparoscopic repair[90]. In addition, when tack and transfascial suture techniques were compared using the SF-36, no significant difference was noted between the two approaches[52,53,88].

Only two of the quality of life assessment methods are hernia specific. These include the Carolinas comfort scale and the hernia-related quality of life survey (HerQLes). The Carolinas comfort scale assesses pain, limitations in movement, and mesh sensation for eight daily activities. Colavita et al[91] assessed 710 patients and showed worse quality of life one month after laparoscopic repair when compared to open repair, but there was no long-term difference. Two other studies showed large hernia defects and the presence of preoperative pain to be strong predictors of a short-term decrease in quality of life, most likely due to pain[92,93]. The HerQLes is a newly developed assessment first reported by Krpata et al[94]. It associates hernia specific physical limitations with overall physical and mental effects on quality of life. It shows an advantage in laparoscopic repair at 4 wk, but no difference at 6 mo. Based on the available literature, it appears that there might be some improvement in short-term quality of life with the laparoscopic approach, but this benefit balances out in the long run.

Most surgeons attempt to decrease modifiable risk factors through patient encouragement; however, there are very few multidisciplinary programs that actively and successfully accomplish this. Further research is required to validate methods to decrease known modifiable risk factors, such as obesity and smoking. Furthermore, only 20% to 27% of hernias are repaired laparoscopically, despite the benefits noted above[12,18].

Considering the plethora of procedural and equipment options, surgeons need criteria to develop a tailored surgical technique for each patient, including surgical approach, mesh material, fixation material, and fixation method. Several algorithms have been developed for operative planning, but no one method has become ubiquitous. Eid et al[95] developed an algorithm to stratify obese patients, taking into account body mass index, abdominal wall thickness, and presence of symptoms. Parker et al[96] proposed another algorithm to determine open vs laparoscopic component separation, and concomitant open vs laparoscopic ventral hernia repair. Further research is needed to create a reliable and validated algorithm for surgical selection.

No one mesh has become dominant in intraperitoneal onlay repair. There is an ongoing study at Washington University determining the adhesion profile of these meshes[29]. Several other studies have attempted to stratify mesh characteristics, but the numbers are too small to draw definitive conclusions[24]. Mesh technology continues to develop ahead of validating research. Long-term absorbable meshes, self-gripping meshes, and titanium reinforced meshes are now available for use. The robotic platform increases the ability to place mesh in the retrorectus space, which may obviate the need for different mesh materials. Surgeons and patients would benefit from more level 1 clinical studies scientifically comparing the risks and benefits of evolving mesh technologies.

Non-standard laparoscopic techniques are being increasingly utilized, such as simultaneous primary hernia closure, retrorectus mesh placement, concomitant component release, and mesh fixation, in order to decrease wound complications, postoperative pain, and hernia recurrence. Surgeons are more likely to attempt laparoscopic repair of more complex hernias, such as incarcerated/strangulated ventral hernias, as their collective experience grows. In the same way, newer fixation methods might decrease postoperative pain, such as barbed suture or fibrin sealant, but may risk re-herniation if they do not provide adequate fixation. Simultaneous component release has gained popularity as it allows reconstruction of the midline. Considering the relatively low incidence of complications, mesh registries may be useful to increase the power of future studies.

The ease of robotics may decrease the learning curve for surgeons, making a good laparoscopic surgeon better able to replicate the tenets of open repair. It permits relatively easy access to the anterior abdominal wall, allowing the surgeon to perform the ideal repair for that patient - including possible primary defect closure, retrorectus mesh placement, intracorporeal suturing, and concomitant posterior component release. It also might allow for standardization of surgical technique in order to develop a reliable approach to hernia repair that can be offered to an increasing number of patients. Further research is needed to determine the ability to decrease patient morbidity vs the increased cost of technology.

Patient reported outcome measures (PROM) are standardized measures used to assess symptom status, physical function, mental health, social function, and wellbeing, with the goal of patient centered improvement of care. This system has been implemented in the United Kingdom and the National Health Service for many years with variable success[97]. Previously discussed studies have attempted to assess quality of life using similar standardized measures for ventral hernia repair, such as the SF-36, Carolinas comfort scale, and the HerQLes. Thus far, these studies have been experimental and have not been used to guide treatment. Further research might develop specific PROM that may be used to enable cost analysis, standardization of treatment, and quality improvement.