INTRODUCTION — Ventral incisional hernia (VIH) formation following abdominopelvic surgery is common. VIHs negatively affect an individual's quality of life by causing pain, diminishing function, and creating poor cosmesis. Unfortunately, VIH repair can be associated with poor short-term and long-term outcomes. (See "Clinical features, diagnosis, and prevention of incisional hernias".)
As such, there is increasing interest in the role of prophylactic mesh at the time of abdominal closure to prevent VIH from ever occurring. However, placing mesh to repair a hernia and placing mesh prophylactically to prevent a hernia are inherently different, with the former generally accepted and the latter much more controversial.
This topic will discuss the benefits/risks, patient selection, and techniques of prophylactic mesh placement during abdominopelvic surgery. The use of mesh for VIH repair is discussed elsewhere. (See "Management of ventral hernias".)
BENEFITS AND RISKS — Although prophylactic mesh placement may reduce the short-term risk of ventral incisional hernia formation, longer-term data suggest that complications may outweigh the short-term benefits.
Short-term benefits — The main advantage to prophylactic mesh placement is a decrease in ventral incisional hernia (VIH) formation, which is strongly supported by the literature. However, only a fraction of the published trials had greater than 80 percent follow-up for at least 24 months (table 1), and none reported follow-up greater than five years [1]. Studies with less than 80 percent follow-up are at serious risk for bias, and results need to be interpreted with caution [2].
Midline incisions — A meta-analysis of 12 studies (1768 patients) with at least 24 months of follow-up showed a reduction in VIH risk using prophylactic mesh compared with no mesh (11.1 versus 21.3 percent, risk ratio [RR] 0.32, 95% CI 0.19-0.55) [1]. Furthermore, there was no difference in surgical site infection with prophylactic mesh versus no mesh (9.1 versus 8.9 percent, RR 1.08, 95% CI 0.82-1.43). There was an increase in the risk of surgical site occurrence (eg, seroma, hematoma, wound dehiscence) using prophylactic mesh (14.2 versus 8.9 percent, RR 1.57, 95% CI 1.19-2.05).
These results must be interpreted with caution, as publication bias (eg, trials showing a difference are more likely to be published) may lead to an overestimation of the true effect. When adjusted for publication bias, the effect size is reduced by half (RR 0.52; 95% CI 0.39-0.70) [1].
Parastomal and off-midline incisions — There are numerous randomized controlled trials assessing the role of parastomal and off-midline incisions, but only two for parastomal patients and one for off-midline incisions reported at least 80 percent follow-up at two or more years.
●In the two studies assessing prevention of parastomal hernias, the rates of parastomal hernia formation with prophylactic mesh were 15 and 25 percent versus 41 percent and 64 percent without mesh [3,4]. There was no difference in surgical site infection with prophylactic mesh versus no mesh (0 to 21 percent versus 0 to 21 percent). There was also no difference in surgical site occurrence, such as seroma, hematoma, and wound dehiscence, with prophylactic mesh versus no mesh (0 to 20 percent versus 0 to 20 percent).
●For off-midline hernias, one large randomized trial demonstrated a reduction in hernia formation using mesh with no difference in wound infections, seromas, quality of life, or pain scores [5].
Potential long-term complications — Although the results of prophylactic mesh in the short term are promising, it is unclear whether these benefits will sustain long term or diminish as complications accumulate [6]. Because of that, currently we do not suggest routine prophylactic mesh placement. It is important to assess the long-term outcomes associated with prophylactic mesh prior to widespread dissemination of the practice.
Once a prosthetic mesh is implanted, patients must live with the procedure and prosthetic long term. Mesh complications have been shown to occur years after mesh placement, including reoperation in the presence of a mesh, adhesions, bowel obstructions, or fistulas. Such mesh complications are cumulative over time, and some data suggest that the benefits of mesh placement are offset by mesh complications over time [6]. (See "Management of ventral hernias".)
Furthermore, complications are not all equal, and complications due to mesh can be quite severe, such as enterocutaneous fistulas and chronic mesh infections requiring eventual mesh explantation. Trials that show equal complication rates using prophylactic mesh or suture fail to account for the severity of certain complications.
PATIENT SELECTION — Prophylactic mesh may be considered in patients with a substantial abdominopelvic incision (open surgery, hand-assisted laparoscopy, or use of an extended extraction site such as for specimen removal for a hemicolectomy) and one of the following risk factors that have been associated with increased risk of ventral incisional hernia [7-10]:
●Being overweight/obese (body mass index [BMI] ≥25 kg/m2)
●Diabetes
●Smoking
●Malnutrition
●History of previous laparotomy
●Open incision type
●Midline incision
●Presence of ostomy
●Immunosuppression (eg, steroid use)
Prophylactic mesh is generally not used in the following patients in whom the potential risk of mesh outweighs the benefit:
●Patients with a life expectancy less than two years (eg, patients with advanced cirrhosis, metastatic cancer) [11].
●Patients with significant contamination (wound class 4) who are at high risk of mesh infection. (See "Antimicrobial prophylaxis for prevention of surgical site infection in adults", section on 'Wound classification'.)
●Patients at low risk for ventral incisional hernia, such as those undergoing laparoscopic surgery with a limited extraction site and patients with no comorbidities [12,13].
●Patients who have a planned second surgery (eg, a patient with a colostomy who will ultimately need an ostomy reversal).
●Patients with a history of inflammatory bowel disease who may be prone to fistula formation (ie, Crohn's patients).
SURGICAL TECHNIQUE — Currently, prophylactic mesh is not routinely used due to a lack of long-term data, but it may be considered in patients with one of the known risk factors for ventral incisional hernia (VIH) formation discussed above. (See 'Patient selection' above.)
Midline incisions — There are many options for how to place prophylactic mesh at midline incisions. In randomized trials on prophylactic mesh, various mesh types, overlaps, fixations, and locations have been used (table 2) with no clear difference in outcomes. However, based on available data, the following are the authors' recommendations.
Mesh type — With regards to the type of mesh, surgeons have three options: synthetic, biologic, or bioabsorbable mesh. There are potential risks and benefits to each mesh. Available data are limited and conflicting, and practice patterns vary depending on surgeon preference. In our practice, we use mid-density synthetic mesh for prophylactic mesh placement.
●Synthetic mesh has been shown to have low rates of hernia recurrence, but it may be associated with increased risk of surgical site infection and mesh infection [14]. In addition, synthetic mesh is permanent and has the potential to lead to long-term mesh complications. (See 'Potential long-term complications' above.)
●Biologic mesh has traditionally been used in contaminated or emergency cases with the premise that it was associated with fewer wound complications than synthetic mesh [15]. In a randomized trial, there was no difference in abdominal wall complications after emergency abdominal surgery with biologic mesh compared with no mesh; however, abdominal wall complications requiring reoperation were more frequent with biologic mesh [16]. In ventral hernia repair, biologic mesh is associated with more major complications, including mesh infection, hernia recurrence, and reoperation, compared with synthetic mesh [17-19].
●Bioabsorbable mesh is a slowly resorbable synthetic mesh. Some surgeons believe they are associated with a lower risk of surgical site infections and hernia recurrence and improved patient abdominal wall function compared with biologic or synthetic mesh [20]. However, data supporting bioabsorbable mesh are limited to small case series.
Mesh overlap — The ideal amount of mesh overlap in prophylactic mesh placement is unknown. In our practice, we aim for at least 3 cm of overlap for prophylactic mesh. In VIH repair, a minimum of 5 cm of mesh overlap is widely accepted. However, less may be adequate for prophylactic mesh. While there is no prospective or randomized study on this, a study using an incisional hernia model demonstrated that 3 cm of mesh overlap was enough to prevent mesh dislocation [21].
Mesh fixation — Mesh fixation is also largely unstudied in prophylactic mesh. In our practice, we fixate mesh using a single-crown technique in laparoscopic cases. In open cases, mesh placed in the preperitoneal or retromuscular space is secured using suture.
Techniques for fixation vary by mesh location but include suture, transfascial sutures, single-crown tacks, double-crown tacks, and glue. With intraperitoneal mesh placement during laparoscopic ventral hernia repair, glue fixation has been associated with a higher hernia recurrence rate than tacks [22]. However, glue fixation has been acceptable for retromuscular and onlay repair of ventral hernias as well as during inguinal hernia repair (laparoscopic and open). In addition, there is some evidence that transfascial suture fixation is associated with greater postoperative pain than other methods of fixation; however, other studies show no difference in postoperative pain between tacks or suture [23-25].
Mesh location — There are a variety of possible planes for mesh placement (figure 1), and each has advantages and disadvantages [26]. Due to superior outcomes compared with other mesh locations, we prefer retromuscular or preperitoneal mesh placement for open cases and intraperitoneal mesh placement for laparoscopic cases when feasible.
●Onlay – Skin flaps are elevated off the anterior rectus sheath to allow for 3 cm of mesh overlap on either side of the incision. When possible, perforating vessels, which lie in the 4 cm around the umbilicus, should be preserved. Skin flaps should be minimized in size as they increase the incidence of wound complications, such as seroma and surgical site infection. The anterior fascia is closed using 0.5 x 0.5 cm bites with 0-PDS suture. An uncoated synthetic mesh is placed on the fascia and secured with interrupted suture. Skin flaps can be tacked down using quilting sutures to prevent seroma formation. A closed suction drain is placed over the mesh. Skin is closed over the mesh.
●Intraperitoneal – All adhesions are cleared from the abdominal wall. A mesh size is chosen that will allow for 3 cm of overlap on all sides of the incision. In clean cases, a coated synthetic mesh is used. In laparoscopic cases, the fascia is closed using interrupted 0-PDS on a suture passer. The mesh is then secured using transfascial sutures preplaced on each side of the mesh using a suture passer. A single crown of tacks is placed circumferentially. In open cases, stay sutures are placed in the mesh superiorly, inferiorly, and laterally so that it will lie flat with no wrinkles or folding once the anterior rectus fascia is closed. Interrupted 0-PDS sutures are then placed in between the stay sutures to ensure there is no gapping between the mesh and the abdominal wall. Once the mesh is secured, the fascia is closed using running 0-PDS suture with 0.5 x 0.5 cm bites.
●Retromuscular/preperitoneal – All adhesions are cleared from the abdominal wall. The preperitoneal or retromuscular plane is developed. An uncoated synthetic mesh is chosen that will allow for 3 cm of mesh overlap on all sides. The peritoneum and/or posterior rectus sheath is closed with running 0-PDS suture. The mesh is placed in the developed plane. Fixation is optional but can be performed with glue or sutures. The anterior rectus sheath is closed with 0.5 x 0.5 cm bites using 0-PDS.
In ventral hernia repair, retromuscular/preperitoneal placement is associated with the lowest rate of wound complications and the lowest rate of hernia recurrence [27]. Performing this repair requires additional training for most surgeons, has technical challenges, requires additional operative duration, and requires violation of a potential space. Intraperitoneal mesh has the second-best results in terms of hernia recurrence. However, this places mesh in contact with intra-abdominal contents, which can lead to intra-abdominal adhesions and has potential for fistula formation. Onlay mesh has higher rates of wound complications and hernia recurrence than retromuscular/preperitoneal or intraperitoneal mesh. However, it is technically easier to place and may be useful in certain situations. Inlay (bridged) repair is associated with a high risk of hernia recurrence and should be avoided when fascial closure is possible.
Randomized trials of prophylactic mesh in patients undergoing laparotomy have included onlay, retromuscular/preperitoneal, and intraperitoneal meshes. On network meta-analysis of these trials, retromuscular/preperitoneal mesh was associated with the lowest rate of VIH. Onlay mesh placement was associated with a higher rate of wound complications compared with retromuscular/preperitoneal; however, there was no difference in other short-term complications, including surgical site infection, reintervention, or readmission [28]. Patients with onlay mesh reinforcement and an infectious complication had a significantly higher risk of developing an incisional hernia compared with those in the retromuscular/preperitoneal group [29].
Parastomal incisions — The optimal technique for prophylactic mesh placement at the time of ostomy creation is unknown (figure 2). Techniques used in randomized trials are variable (table 3). The authors prefer to use a keyhole technique via a midline approach using a polypropylene mesh with 3 cm of mesh overlap in the retromuscular space, which is technically more challenging than other approaches but provides excellent outcomes.
In general, a preoperative bowel preparation should be given the night before surgery. The stoma site should be marked preoperatively by the stoma nurse to avoid any skin folds. (See "Overview of surgical ostomy for fecal diversion", section on 'Ostomy construction'.)
Keyhole technique via a midline approach — Through a midline incision, all intra-abdominal adhesions are taken down. The plane between the rectus muscle and the posterior rectus sheath or peritoneum (below the arcuate line) is developed. The plane should be developed 3 cm circumferentially around the stoma. The posterior rectus sheath/peritoneum is closed in the midline and around the stoma using running 0-PDS suture, leaving just enough space for the ostomy to pass through. A polypropylene mesh is incised from one side toward the center, where a cruciate incision or circular defect is cut at 50 percent of the bowel width to allow for ostomy passage [30]. The mesh is placed around the stoma, and the incision in the mesh is closed with 2-0 permanent suture. The mesh can be secured to the posterior rectus sheath using 2-0 interrupted Vicryl suture. The anterior rectus sheath is then closed with small bites of running 0-PDS [3,31].
Keyhole technique via ostomy site — A circular incision is made at the ostomy site. A cruciate or circular incision is made in the anterior rectus sheath. A space is developed between the rectus muscle and the posterior rectus sheath using blunt dissection. A polypropylene mesh prepared with a circular cutout large enough to allow for passage of the ostomy is placed in the retromuscular space. No mesh fixation is required. The ostomy is created in the standard fashion [32].
Sugarbaker technique — Through a midline incision or laparoscopically, the colon is fixed laterally to the abdominal wall. The stoma defect and the lateral colon are covered with mesh. A composite polypropylene mesh (mesh with a visceral and parietal side) is preferred by the authors. The mesh is fixated posterior laterally with running absorbable suture, allowing for the passage of the colon without restriction. The remaining three sides of the mesh are fixed with interrupted transfascial sutures [33].
NONCLINICAL ISSUES — There are very few surgeons using prophylactic mesh. Aside from concerns about unknown long-term complications, there are several nonclinical barriers to prophylactic mesh placement:
●Surgeon inexperience with abdominal wall reconstruction – Many surgeons who might see benefit from prophylactic mesh (eg, colorectal surgeons, transplant surgeons, and gynecologists) may not be familiar with advanced abdominal wall reconstruction. In the majority of randomized trials on prophylactic mesh placement, mesh was placed by experts, not novices. Therefore, the outcomes of these studies may not be replicable when surgery is performed by less experienced surgeons. To overcome this obstacle, either all surgeons need to be trained on how and when to place prophylactic mesh, or separate surgeons skilled in abdominal wall reconstruction could be used as "closing teams" in cases where mesh placement is warranted.
●Lack of reimbursement – Placement of mesh adds extra time and risk to a procedure, but at present there is limited reimbursement. As of 2016, there is a CPT code for prophylactic mesh placement (0437T); however, this is a category III code, which is used for research and tracking. In order to have a reimbursement value assigned, it would need to be changed to a category I code.
●Medicolegal concerns – More and more lawsuits are filed for complications from mesh placement. Many surgeons are not willing to accept the risk of a lawsuit only to prevent a potential problem.
Prophylactic mesh is not yet ready for widespread adoption, as there are still many unanswered questions. Future studies with long-term follow-up (at least 5 to 10 years) need to address the optimal type and location of prophylactic mesh; a standardized method for billing and reimbursement needs to be developed; and, finally, prophylactic mesh needs to be endorsed by administration and surgical societies before it can be accepted as a common practice.
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: Abdominal incisions and closure" and "Society guideline links: Parastomal hernia".)
SUMMARY AND RECOMMENDATIONS
●Although prophylactic mesh placement may reduce the short-term risk of ventral incisional hernia formation, longer-term data suggest that complications may outweigh the short-term benefits:
•For midline incisions, prophylactic mesh placement may reduce ventral incisional hernia formation (11.1 versus 21.3 percent) and increase overall surgical site occurrences (14.2 versus 8.9 percent) but not surgical site infections (9.1 versus 8.9 percent) (table 1). (See 'Midline incisions' above.)
•For off-midline and parastomal incisions, prophylactic mesh placement also reduces ventral incisional hernia formation without increasing wound complications, but available data are more limited. (See 'Parastomal and off-midline incisions' above.)
•Mesh complications, including reoperation in the presence of a mesh, adhesions, bowel obstructions, fistulas, and chronic mesh infection requiring explantation, may occur years after mesh placement. The long-term complication profile of mesh placement is unknown, and it is not clear if the benefit of ventral incisional hernia prevention is worth the risk of long-term complications of mesh placement. (See 'Potential long-term complications' above.)
●We suggest against routine prophylactic mesh placement for most patients undergoing laparotomy (Grade 2C). However, some surgeons may choose to use prophylactic mesh in selected patients, such as those with one or more known risk factors for ventral incisional hernia. (See 'Patient selection' above.)
●When indicated, there are many options for prophylactic mesh placement at midline incisions, which vary by mesh type, location, overlap, and fixation (table 2). The authors' practice is to place a mid-weight synthetic mesh in the retromuscular/preperitoneal location with a minimum of 3 cm of overlap and fixated with sutures for open cases, and a coated synthetic mesh intraperitoneally for laparoscopic cases. (See 'Midline incisions' above.)
●When indicated, there are three common techniques of prophylactic mesh placement at parastomal incisions (table 3). The authors' practice is a keyhole technique via a midline approach using a polypropylene mesh with 3 cm of mesh overlap in the retromuscular space. (See 'Parastomal incisions' above.)
●Prophylactic mesh is not yet ready for widespread adoption, as there are still many unanswered questions, including unknown long-term efficacy and complications, surgeon inexperience, lack of reimbursement, and medicolegal concerns. (See 'Potential long-term complications' above and 'Nonclinical issues' above.)
