Many surgeons utilize biologic mesh for elective complex ventral hernia repair (VHR; large hernias, contaminated fields, or patients with comorbid conditions). However, no randomized controlled trials (RCTs) have compared biologic and synthetic mesh. We hypothesize biologic mesh would result in fewer major complications at one-year post-operative compared with synthetic mesh.

Materials and Methods:

We performed a single-center, pilot RCT. All eligible patients undergoing complex, open VHR were randomly assigned to receive biologic or synthetic mesh placed in the retromuscular position. Primary outcome was major complications, namely, a composite of mesh infection, recurrence, or re-operation at one-year post-operative. Secondary outcomes included surgical site infections (SSI), seromas, hematomas, wound dehiscence, re-admissions, and Clavien-Dindo complication grade. Outcomes were assessed using Fisher exact test and Bayesian generalized linear models.

Results:

Of 87 patients, 44 were randomly assigned to biologic mesh and 43 to synthetic mesh. Most cases were wound class 2–4 (68%) and 75% had a hernia width >4 cm. Most patients were obese (70%) and had an American Society of Anesthesiogists (ASA) score of 3–4 (53%). Compared with patients in the synthetic mesh group, patients in the biologic mesh group had a higher percentage of: major complications at one-year post-operative (42.4% vs. 21.6%; relative risk [RR] = 1.96 [95% confidence interval {CI} = 0.94–4.08]; number needed to harm = 4.8; p = 0.071); SSI (15.9% vs. 9.3%; RR = 1.71 [95% CI = 0.54–5.42]; p = 0.362); wound dehiscence (25.0% vs. 14.0%; RR = 1.79 [95% CI = 0.73–4.41]; p = 0.205); and re-admissions (22.7% vs 9.3%; RR = 2.44 [95% CI = 0.83–7.20]; p = 0.105). Bayesian analysis demonstrated that compared with synthetic mesh, biologic mesh had a 95% probability of increased risk of major complications at one-year post-operative. No clear evidence of a difference was found on seromas, hematomas, or Clavien-Dindo complication grade.

Conclusion:

In elective complex open VHR, biologic mesh demonstrated no benefit compared with synthetic mesh in one-year outcomes. Moreover, Bayesian analysis suggests that biologic mesh may have an increased probability of major complications.

• Patients who had their repair using biologic mesh had a high percentage of major post op complications (42.4%) compared to synthetic mesh (21.6%).
• Biologic mesh had a higher rate of wound dehiscence (25%) compared to synthetic (14%)
• Biologic mesh had a higher rate of readmissions (22.7%) vs. synthetic (14%)

Biologic mesh is widely used for reinforcing contaminated ventral hernia repairs; however, it is expensive and has been associated with high rates of long-term hernia recurrence. Synthetic mesh is a lower-cost alternative but its efficacy has not been rigorously studied in individuals with contaminated hernias.

Materials and Methods:

This multicenter, single-blinded randomized clinical trial was conducted from December 2012 to April 2019 with a follow-up duration of 2 years. The trial was completed at 5 academic medical centers in the US with specialized units for abdominal wall reconstruction. A total of 253 adult patients with clean-contaminated or contaminated ventral hernias were enrolled in this trial. Follow-up was completed in April 2021.

The primary outcome was the superiority of synthetic mesh vs biologic mesh at reducing risk of hernia recurrence at 2 years based on intent-to-treat analysis. Secondary outcomes included mesh safety, defined as the rate of surgical site occurrence requiring a procedural intervention, and 30-day hospital direct costs and prosthetic costs.

Results:

A total of 253 patients (median [IQR] age, 64 [55-70] years; 117 [46%] male) were randomized (126 to synthetic mesh and 127 to biologic mesh) and the follow-up rate was 92% at 2 years. Compared with biologic mesh, synthetic mesh significantly reduced the risk of hernia recurrence (hazard ratio, 0.31; 95% CI, 0.23-0.42; P < .001). The overall intent-to-treat hernia recurrence risk at 2 years was 13% (33 of 253 patients). Recurrence risk with biologic mesh was 20.5% (26 of 127 patients) and with synthetic mesh was 5.6% (7 of 126 patients), with an absolute risk reduction of 14.9% with the use of synthetic mesh (95% CI, −23.8% to −6.1%; P = .001). There was no significant difference in overall 2-year risk of surgical site occurrence requiring a procedural intervention between the groups (odds ratio, 1.22; 95% CI, 0.60-2.44; P = .58). Median (IQR) 30-day hospital direct costs were significantly greater in the biologic group vs the synthetic group ($44 936 [$35 877-$52 656] vs $17 289 [$14 643-$22 901], respectively; P < .001). There was also a significant difference in the price of the prosthetic device between the 2 groups (median [IQR] cost biologic, $21 539 [$20 285-$23 332] vs synthetic, $105 [$105-$118]; P < .001).

Conclusion:

Synthetic mesh demonstrated superior 2-year hernia recurrence risk compared with biologic mesh in patients undergoing single-stage repair of contaminated ventral hernias, and both meshes demonstrated similar safety profiles. The price of biologic mesh was over 200 times that of synthetic mesh for these outcomes.

• Recurrence risk for synthetic mesh was significantly lower (5.6%) in comparison to biologic mesh (20.5%) = an absolute risk reduction of 14.9% using synthetic mesh
• Hospital direct costs were significantly higher for biologic mesh compared to synthetic mesh

Ventral hernia repair is one of the most common operations performed worldwide, and using mesh is standard of care to decrease recurrence. Biologic meshes are increasingly used to minimize complications associated with synthetic mesh, but with significantly higher cost and unclear efficacy. Until recently, most of the evidence supporting the use of biologic meshes was from retrospective cohorts with high heterogeneity and risk of bias. We aimed to report a meta-analysis of randomized controlled trials comparing the outcomes of synthetic and biologic mesh in elective open ventral hernia repair.

Materials and Methods:

A literature search of PubMed, Embase, and Cochrane Library databases was performed to identify randomized controlled trials comparing biologic and synthetic mesh in elective open ventral hernia repairs. The postoperative outcomes were assessed by means of pooled analysis and meta-analysis. Statistical analysis was performed using RevMan 5.4. Heterogeneity was assessed with I² statistics.

Results:

A total of 1,090 studies were screened, and 22 were fully reviewed. Four randomized controlled trials and 632 patients were included in the meta-analysis. Fifty-eight percent of patients had contaminated wounds (Wound Classification II–IV). Hernia recurrence (odds ratio 2.75; 95% confidence interval 1.76–4.31; P < .00001; I² = 0%) and surgical site infections (odds ratio 1.53; 95% confidence interval 1.02–2.29; P = .04; I² = 0%) were significantly more common in patients with biologic mesh. The rates of seroma, hematoma, and mesh removal were similar in both groups.

Conclusion:

As compared to synthetic mesh, biologic meshes resulted in increased hernia recurrences and surgical site infections. Current evidence supports macroporous, uncoated synthetic mesh as the implant of choice for elective open ventral hernia repair, and its use should be considered even in contaminated cases.

• Hernia recurrence was significantly higher for the biologic group (77 events out of 308) compared to the synthetic group (35 events out of 307).
• Surgical site infections was higher for the biologic group (76 out of 319) vs. the synthetic group (55 out of 313)
• Rates of seroma, hematoma and mesh removal were similar between the biologic and synthetic groups

The introduction of mesh for reinforcement of ventral hernia repair (VHR) led to a significant reduction in hernia recurrence rates. However, it remains controversial whether synthetic or biologic mesh leads to superior out- comes. Recently, hybrid mesh consisting of reinforced biosynthetic ovine rumen (RBOR) has been developed and aims to combine the advantages of biologic and synthetic mesh; however, outcomes after VHR with RBOR have not yet been compared with the standard of care.

Methods:

We performed a retrospective analysis on 109 patients, who underwent VHR with RBOR (n = 50) or synthetic polypropylene mesh (n = 59). Demographic characteristics, comorbidities, postoperative complications, and recurrence rates were analyzed and compared between the groups. Multivariate logistic regression models were fit to assess associations of mesh type with overall complications and surgical site occurrence (SSO).

Results:

Patients who underwent VHR with RBOR were older (mean age 63.7 ver- sus 58.8 years, P = 0.02) and had a higher rate of renal disease (28.0 versus 10.2%, P = 0.01) compared with patients with synthetic mesh. Despite an unfavorable risk profile, patients with RBOR had lower rates of SSO (16.0 versus 30.5%, P = 0.12) and similar hernia recurrence rates (4.0 versus 6.78%, P = 0.68) compared with patients with synthetic mesh. The use of synthetic mesh was significantly associated with higher odds for overall complications (3.78, P < 0.05) and SSO (3.87, P < 0.05).

Conclusion:

Compared with synthetic polypropylene mesh, the use of RBOR for VHR mitigates SSO while maintaining low hernia recurrence rates at 30-month follow-up.

• The use of synthetic mesh was associated with significantly higher odds for overall complications (32.3%) compared to RBOR (18.0%)
• Hernia recurrence rate was similar between the 2 groups (4.0% for RBOR vs. 6.78% for synthetic)

(# of subjects/ studies, cohort definition etc. )

-Patients were randomly assigned intra-operatively to biologic mesh or synesthetic mesh via a computer generated randomization.

-Follow up period: 1 year

-Inclusion criteria: adult patient (> 18 years) with a complex primary or incisional ventral hernia suited for open repair

-Exclusion criteria: patients with acute infection, patients with severe comorbidities limiting survival beyond 2 years (based on surgeon judgement), patients with high likelihood of being lost in follow up process (out of state or no access to telephone)

-Secondary outcomes: surgical site infections (SSI), seromas, hematomas, wound dehiscence, re-admissions, Clavien-Dindo complication grade

-Biologic mesh had double the percentage of hernia recurrence at 1 year post op (30.3% vs. 13.5%)

-Biologic mesh had higher levels of SSI (15.9% vs. 9.3%), wound dehiscence (25.0% vs. 14.0%) and readmissions (22.7% vs. 9.3%)

-No clear evidence in differences for seromas, hematomas, or clavien-dindo complication grade

-17 patients were lost in the follow up period and thus excluded despite aggressive measures to avoid dropouts (11 in biologic mesh and 6 in synthetic mesh group)

-Patient population: majority of patients were Hispanic or African American females, the generalizability of results could be limited

-Surgeons used in this trial were experts in abdominal wall reconstruction of complex patients w/ high risk for complications so generalizability to surgeons with less case complexity may be reduced

-Only 1 type of biologic mesh was used in this study (the most commonly used type) so it can’t be certain that results can be generalized to all types of biologic mesh

-Follow up period: up to 2 years (30 days, 6 months, 1 year and 2 years)

-Inclusion criteria: patients with a contaminated wound (CDC class II or III) undergoing elective single stage ventral hernia repair, age > 21, hernia defect > 9 cm²

-Exclusion criteria: BMI > 45, chronic immunosuppression, severe malnutrition, pregnancy, smoker, active infection, renal or liver disease

-Secondary outcomes: mesh safety (rate of surgical site occurrence requiring procedural intervention), 30 day hospital direct costs, prosthetic costs

-Absolute risk reduction of 14.9% with the use of synthetic mesh

-No significant difference between mesh groups in 2 year risk of surgical site occurrence requiring procedural intervention

-Median 30 day hospital direct costs was significantly higher in biologic group ($44,936 vs. $17,289)

-Significantly higher costs of prosthetic device in biologic group (21,539 vs. $105).

-Some patients were evaluated clinically by physicians without blinding

-6 month and 1 year follow up rates were variable which could have affected some results

-Initial search yielded 1,090 results. Exclusion criteria narrowed down to 4 RCTs with a total of 632 patients

-Inclusion criteria: RCT, comparison of biologic and synthetic mesh, patients undergoing elective open ventral hernia repair, reported post op outcomes, had mean or median > 12 months, English

-Exclusion criteria: not randomized, had overlapping patient populations, did not compare synthetic mesh with biologic or biosynthetic mesh

-Other outcomes: hematoma, mesh removal

-Biologic mesh resulted in increased odds for SSIs (surgical site infections) compared to synthetic mesh (all studies)

-No significant difference in rates of seromas (all studies)

-No significant difference in rates of hematomas (3 of 4 studies)

-No significant difference in rates of mesh removal (3 of 4 studies)

-Limited amount of studies applied to individuals with would class IV (therefore it is believed that the results should not be generalized to this group of patients and further testing is needed)

-Most patients received similar types of mesh between the 2 groups so it is not clear if results can be generalized to other types of mesh

-The use of high volume and experienced surgeons can make it difficult to generalize to similar surgeries with other surgeons

-Inclusion criteria: patients > 18 years, open VHR operated on between 2002 and 2022, implantation of RBOR or prolene mesh

-Exclusion criteria: presence of umbilical hernia or multiple ventral hernias, combination of multiple mesh types, active abdominal infection, concomitant procedures in addition to VHR, laparoscopic repair

-Recurrence

-Hematoma

-Seroma

-Wound complication

-Abdominal infection

Fistula

-Patients who had a VHR using RBOR had similar recurrence rates (4.0%) to repairs using synthetic mesh (6.78%).

-The use of synthetic mesh was significantly associated with higher odds for overall complications

-RBOR repair had lower abdominal infection rates (2.00% vs. 8.47%).

-Retrospective nature

-Differing follow up periods (5 month mean follow up difference) between the 2 groups which can contribute to differences in hernia recurrence rates