Fibroblast matrix implants-a better alternative for incisional hernia repair?

The standard surgical procedure for abdominal hernia repair with conventional prosthetic mesh still results in a high recurrence rate. In the present study, we propose a fibroblast matrix implant (FMI), which is a three-dimensional (3D) poly-L-lactic acid scaffold coated with collagen (matrix) and seeded with fibroblasts, as an alternative mesh for hernia repair. The matrix was seeded with fibroblasts (cellularized) and treated with a conditioned medium (CM) of human Umbilical Cord Mesenchymal Stem Cells (hUC-MSC). Fibroblast proliferation and function were assessed and compared between treated with CM hUC-MSC and untreated group, 24 h after seeding onto the matrix (n= 3). To study the matricesin vivo,the hernia was surgically created on male Sprague Dawley rats and repaired with four different grafts (n= 3), including a commercial mesh (mesh group), a matrix without cells (cell-free group), a matrix seeded with fibroblasts (FMI group), and a matrix seeded with fibroblasts and cultured in medium treated with 1% CM hUC-MSC (FMI-CM group).In vitroexamination showed that the fibroblasts' proliferation on the matrices (treated group) did not differ significantly compared to the untreated group. CM hUC-MSC was able to promote the collagen synthesis of the fibroblasts, resulting in a higher collagen concentration compared to the untreated group. Furthermore, thein vivostudy showed that the matrices allowed fibroblast growth and supported cell functionality for at least 1 month after implantation. The highest number of fibroblasts was observed in the FMI group at the 14 d endpoint, but at the 28 d endpoint, the FMI-CM group had the highest. Collagen deposition area and neovascularization at the implantation site were observed in all groups without any significant difference between the groups. FMI combined with CM hUC-MSC may serve as a better option for hernia repair, providing additional reinforcement which in turn should reduce hernia recurrence.

Endoscopic Mini- or Less-Open Sublay operation with transversus abdominis muscle release using a single-port platform for incisional hernia: A video vignette.

TECHNIQUE: The Endoscopic Mini- or Less-open Sublay operation (EMILOS) is a transhernial repair that allows endoscopic dissection and mesh placement in the retrorectus/retromuscular space, and simultaneous transversus abdominis release (TAR) for larger hernias. The operative summary is as follows. 1 A 7-cm longitudinal skin incision was made immediately above the hernial orifice. 2 The hernial sac was circumferentially dissected to the border of the defect, and the abdomen was opened. 3 The posterior rectus sheath (PRS) was incised approximately 5 mm lateral to the medial border of the rectus sheath to enter the retrorectus space. 4 Exploratory laparoscopy was performed, and the peritoneum was closed. 5 A single port platform was attached to the wound, and the abdominal wall was insufflated. The retrorectal space was dissected laterally to the outer edge of the rectus abdominis muscle. The linea alba was incised at least 5 cm cranially and caudally from the border of the hernia defect to obtain sufficient mesh overlap. 6 The TAR was added to the left side to facilitate medial advancement of the PRS. (7) The PRS was approximated with continuous suture. A self-gripping mesh was trimmed and implanted in the retrorectus space. The mesh was secured with 3-0 absorbable sutures (8) A closed-suction drain was placed on the mesh, and the wound was trimmed and closed. RESULTS: The postoperative course was uneventful. No recurrence was observed at 6-month follow-up. CONCLUSIONS: This technique may be advantageous because it allows minimal skin incision with physiological reconstruction of abdominal wall.

Devices in Hernia Surgery.

Despite the heavy reliance of surgeons on mesh with which to repair hernias, less attention is paid to the technical specifications of mesh and/or regulatory processes for bringing medical devices to market during surgical training. This article summarizes some of the key controversies and points regarding mesh materials and regulatory processes related to mesh devices.

Slowly absorbable mesh versus standard care in the management of contaminated midline incisional hernia (COMpACT-BIO): a multicentre randomised controlled phase III trial including a health economic evaluation.

INTRODUCTION: Incisional hernia (IH) is the most frequent mid-term and long-term complication after midline laparotomy. The current standard treatment includes repair using a mesh. In a contaminated field, the use of a non-absorbable mesh increases the risk of surgical site infection and the costs. Slowly absorbable meshes are safe in contaminated fields, but no data have been reported regarding their long-term recurrence rate. COMpACT-BIO is a multicentre prospective randomised controlled phase III trial designed to compare the 3-year recurrence rate in patients undergoing contaminated IH repair with either a slowly absorbable mesh or standard care. METHODS: In patients undergoing midline IH repair in a contaminated surgical field (grade III of the modified Ventral Hernia Working Group classification), the COMpACT-BIO study compares the use of a slowly absorbable mesh with that of conventional care according to standardised surgical procedures (primary closure, non-absorbable synthetic mesh or biologic mesh, at the discretion of the surgeon). Randomisation is done during surgery before closure the fascia with an allocation ratio of 1:1. The choice of the slowly absorbable mesh is left to the criteria of each centre. The primary endpoint is the proportion of patients with scan-confirmed IH recurrence within 3 years after repair. ETHICS/DISSEMINATION: This trial is conducted in compliance with international standards for research practice and reporting. Written informed consent will be obtained from patients prior to inclusion. All data were identified and anonymised prior to analysis. The protocol has been approved by an Institutional Review Board (2020-A0823-36/SI:20.07.03.66831), and will be conducted in compliance with the CONSORT (Consolidated Standards of Reporting Trials) statement. Results will be submitted for publication in peer-reviewed medical journals and presented to patients and healthcare professionals. PROTOCOL VERSION: Version 2-13 October 2020. TRIAL REGISTRATION NUMBER: NCT04597840.

Laparoscopic Paraesophageal Hernia Repair: To Mesh or not to Mesh. Systematic Review and Meta-analysis.

OBJECTIVE: This study aimed to compare outcomes after laparoscopic paraesophageal hernia repair (LPEHR) with mesh or primary repair alone. SUMMARY OF BACKGROUND DATA: High recurrence rates after LPEHR have been reported. Whether the use of mesh improves outcomes remains elusive. METHODS: A systematic literature search was performed to identify randomized controlled trials (RCTs) comparing LPEHR with mesh repair versus suture repair alone. Early (≤6 months) and late (>6 months) recurrence rates were used as primary endpoints to assess efficacy. Intraoperative complications, overall morbidity, and reoperation rates were used as secondary endpoints to assess safety. A meta-analysis was conducted using relative risks (RR) with 95% confidence intervals (CI) for the analyzed outcomes. RESULTS: Seven RCTs comparing mesh (n = 383) versus suture only (n = 352) repair were included for analysis. Patients undergoing LPEHR with mesh reinforcement had similar early (RR = 0.74, 95% CI = 0.26-2.07, P = 0.46) and late (RR = 0.75, 95% CI = 0.27-2.08, P = 0.48) recurrence rates as those with primary repair. Similar recurrence rates were also found when stratifying the analysis by the type of mesh utilized (absorbable and nonabsorbable). Intraoperative complications (RR = 1.03, 95% CI = 0.33-3.28, P = 0.92) and reoperation rates (RR = 0.75, 95% CI = 0.29-1.92, P = 0.45) were also similar in both groups. Overall morbidity, however, was higher after mesh repair with nonabsorbable mesh (RR = 1.45, 95% CI = 1.24-1.71, P < 0.01). CONCLUSIONS: Patients undergoing LPEHR have similar early and late recurrence rates with either mesh reinforcement or suture only repair, regardless of the type of mesh utilized. Overall morbidity, however, seems to be higher in patients repaired with nonabsorbable mesh.

Are the relative benefits of open versus laparoscopic intraperitoneal mesh repair of umbilical hernias dependent on the diameter of the defect?

BACKGROUND: The aim of this study was to assess whether the respective values of open and laparoscopic intraperitoneal repairs of umbilical hernias are related to the European Hernia Society diameter of defects. METHODS: This registry-based study compared the early and 2-year outcomes of 776 open versus 1,019 consecutive laparoscopic intraperitoneal repairs performed from 2011 to 2019. RESULTS: Intraperitoneal mesh repair, either laparoscopic or open, was found to be a safe procedure at the 2-year follow-up. The incidence of reoperated bowel obstructions was 0.3%. Compared with the open group: (1) postoperative surgical site occurrences in small (<2 cm) or medium (2-4 cm) hernias (0.3% vs 2.4%; P = .041; 1.4% vs 5.9%; P = .0002); (2) recurrence rates in large (≥4 cm) umbilical hernias (0.0% vs 8.6%; P = .0195); and (3) cumulative reoperation rates (0.9% vs 2.2%; P = .021) were significantly better in the laparoscopic group. Conversely, the rate of early pain on day 1 and 1 month postsurgery was higher in the laparoscopic group, for all hernia sizes (P < .001). The rate of moderate or severe chronic pain at 2 years was significantly higher in the laparoscopic group (8.1% vs 2.4%; P = .049) for small hernias. CONCLUSION: The respective benefit to drawback ratios for open versus laparoscopic intraperitoneal repairs were related to the European Hernia Society diameter of hernia defect. In medium-large hernias, the benefits of laparoscopic repair overrode its drawbacks. In small hernias, the low recurrence rate, reduced early and chronic pain, and better rate of ambulatory surgery suggest there is still a place for open repair.

Microvascular Free Tissue Transfer for Reconstruction of Complex Abdominal Wall Defects.

SUMMARY: Patients with significant loss of abdominal wall soft tissue represent a reconstructive challenge. The purpose of this study was to describe the authors' experience using microvascular free tissue transfer to repair complex abdominal wall defects with insufficient overlying soft tissue. In this report, the authors highlight their techniques and experiences in performing microvascular free tissue transfer to the abdominal wall for these massive, complex defects. In total, 14 patients who underwent 16 free-flap reconstructions were included in the series. The patients' mean age was 50 ± 14 years, and mean body mass index was 27 ± 5 kg/m2. The mean hernia defect size was 412 ± 149 cm2. Ten flaps were fasciocutaneous anterolateral thigh flaps, one myocutaneous anterolateral thigh flap, two subtotal thigh flaps, one myocutaneous latissimus dorsi flap, one parascapular/latissimus dorsi flap, and one free filet of the lower leg. Five cases (36 percent) developed hernia recurrence, and seven developed surgical site complications. All flaps survived, with no total flap loss. This report highlights that microsurgical free tissue transfer in combination with mesh repair is a safe and reliable method for restoring complex, large, full-thickness abdominal wall defects. This case series illustrates a number of techniques and considerations that are of importance to achieve a favorable outcome when faced with these complex defects. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Resorbable Synthetic Ventral Hernia Repair in Contaminated Fields: Outcomes with Poly-4-Hydroxybutyrate Mesh.

BACKGROUND: Hernia repair in the setting of contamination poses unique challenges, including complications such as recurrence and mesh infection. The ideal contaminated hernia repair including type of mesh use remains controversial. Poly-4-hydroxybutyrate is a biosynthetic scaffold for soft-tissue reinforcement and hernia repair and is potentially useful in contaminated hernia repair. The authors aim to describe postoperative outcomes, recurrence, and patient-reported outcomes after contaminated hernia repair with poly-4-hydroxybutyrate. METHODS: Adult patients (≥18 years) undergoing a contaminated hernia repair with poly-4-hydroxybutyrate (Phasix) performed by a single plastic surgeon between January of 2015 and May of 2020 were identified. Patients with a ventral hernia defect and a Centers for Disease Control and Prevention wound class of II, III, or IV were included. Primary outcomes included recurrence, surgical-site infection, surgical-site occurrences, and surgical-site infection/occurrences requiring procedural interventions. As a secondary outcome, the authors assessed patient-reported outcomes as defined by the Abdominal Hernia-Q and Hernia-Related Quality of Life Survey. RESULTS: Sixty patients were included with a median age of 52.5 and body mass index of 31 kg/m2. Median defect size was 300 cm2. Twenty-eight patients (46.7 percent) experienced a complication. The most common complications were surgical-site occurrence [n = 20 (33.3 percent)] and surgical-site infection [n = 10 (16.7 percent)]. Median follow-up was 24.2 months, with a recurrence rate of 8.3 percent (n = 4). Overall patient-reported outcomes improved postoperatively, and improvement was not affected by the presence of a complication. CONCLUSIONS: Poly-4-hydroxybutyrate use in contaminated hernia repair shows promising results with an acceptable safety profile. Although complications are frequent in this complex cohort, patient-reported outcomes improvement was significant even in patients with complications. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Medialization after combined anterior and posterior component separation in giant incisional hernia surgery, an anatomical study.

BACKGROUND: To obtain tension-free closure for giant incisional hernia repair, anterior or posterior component separation is often performed. In patients with an extreme diameter hernia, anterior component separation and posterior component separation may be combined. The aim of this study was to assess the additional medialization after simultaneous anterior component separation and posterior component separation. METHODS: Fresh-frozen post mortem human specimens were used. Both sides of the abdominal wall were subjected to retro-rectus dissection (Rives-Stoppa), anterior component separation and posterior component separation, the order in which the component separation techniques were performed was reversed for the contralateral side. Medialization was measured at 3 reference points. RESULTS: Anterior component separation provided most medialization for the anterior rectus sheath, posterior component separation provided most medialization for the posterior rectus sheath. After combined component separation techniques total median medialization ranged between 5.8 and 9.2 cm for the anterior rectus sheath, and between 10.1 and 14.2 cm for the posterior rectus sheath (depending on the level on the abdomen). For the anterior rectus sheath, additional posterior component separation after anterior component separation provided 15% to 16%, and additional anterior component separation after posterior component separation provided 32% to 38% of the total medialization after combined component separation techniques. For the posterior rectus sheath, additional posterior component separation after anterior component separation provided 50% to 59%, and additional anterior component separation after posterior component separation provided 11% to 17% of the total medialization after combined component separation techniques. Retro-rectus dissection alone contributed up to 41% of maximum obtainable medialization. CONCLUSION: Anterior component separation provided most medialization of the anterior rectus sheath and posterior component separation provided most medialization of the posterior rectus sheath. Combined component separation techniques provide marginal additional medialization, clinical use of this technique should be carefully balanced against additional risks.

Four-year follow-up in 33 patients after inguinal hernioplasty using the NeT Plug & Patch device.

AIM: To prove that the Net Plug & Patch is a valid device for the surgical treatment of inguinal hernia. MATERIAL OF STUDY: The authors of a previous study decided to continue the follow-up for a further three years on 33 patients who had had hernia repair surgery using the three-dimensional NeT Plug & Patch device at their Hernia Center. RESULTS: All of the patients involved took part and the follow-up appointments were scheduled as follows: clinical examination at two years; telephone contact at three years and telephone contact and questionnaire at four years. No symptoms were observed at the second, third and fourth year follow-up time-points. There were no cases of recurrence. DISCUSSION: The Lichtenstein technique is currently considered the gold standard. However, many surgeons now prefer to use the MPR (Mesh Plug Repair) technique, despite the potential complications of using a plug. The technique had a short learning curve with no complications associated directly with the plug used such as migration or possible erosion of the adjacent hollow abdominal organs or blood vessels. CONCLUSIONS: the NeT Plug & Patch device thus proved to be comfortable, safe and efficacious in inguinal repair surgery using the MPR technique. KEY WORDS: Mesh Plug Repair (MPR), Plug migration, Trabucco repair.

Total endoscopic sublay mesh repair for umbilical hernias.

ABSTRACT: Umbilical hernias constitute some of the most common surgical diseases addressed by surgeons. Endoscopic techniques have become standard of care together with the conventional open techniques for the treatment of umbilical hernias. Several different approaches were described to achieve laparoscopic sublay repair.We prospectively collected and reviewed the medical records of 10 patients with umbilical hernias underwent total endoscopic sublay repair (TES) at our institution from November 2017 to November 2019. All operations were performed by a same surgical team. The demographics, intraoperative details, and postoperative complications were evaluated.All TES procedures were successfully performed without conversion to an open operation. No intraoperative morbidity was encountered. The average operative time was 109.5 minutes (range, 80-140 minutes). All the patients resumed an oral diet within 6 hours after the intervention. The mean time to ambulation was 7.5 hours (range, 4-14 hours), and mean postoperative hospital stay was 2.2 day (range, 1-4 days). One patient developed postoperative seroma. No wound complications, chronic pain, or recurrence were registered during the follow-up.Initial experiences with this technique show that the TES is a safe, and effective procedure for the treatment of umbilical hernias.

Outcomes of primary and recurrent inguinal hernia repair with prosthetic mesh in a single region over 15 years.

BACKGROUND: Sutured inguinal hernia repairs are now uncommon, with evidence suggesting that those augmented with mesh are associated with a lower recurrence rate. We aimed to explore the suggestion that the established use of mesh does indeed lower the rate of operation for recurrence in a single National Health Service region. METHOD: We collected retrospective Office of Population Censuses and Surveys coded data across one region of all primary and recurrent inguinal hernia repairs over 15 years (2004-2019). Electronic records of recurrent repairs were scrutinised to identify year and type of previous primary repair. RESULTS: In total, 7,234 repairs were performed during this time, of which 289 (4%) were for symptomatic recurrence. Operations for primary repair increased year on year (111 in 2004 to 402 in 2019). Frequency of operation for recurrent herniation declined with increasing use of mesh (8.8% in 2004 to 3.5% in 2019). The majority of repairs (73%) for recurrence were by an open approach. As opposed to an open mesh repair, a primary laparoscopic repair was associated with an earlier recurrence. CONCLUSIONS: Inguinal hernia repairs are increasing in frequency but operations for later symptomatic recurrence following an open primary prosthetic mesh repair are not.

Leveraging a statewide quality collaborative to understand population-level hernia care.

BACKGROUND: Although ventral hernia repair (VHR) is extremely common, there is profound variation in operative technique and outcomes. This study describes the results of a statewide registry capturing hernia-specific variables to understand population-level practice patterns. METHODS: Retrospective analysis of adult patients in a new statewide hernia registry undergoing VHR in 2020. RESULTS: 919 patients underwent VHR across 57 hospitals and 279 surgeons. Hernia width was <2 cm in 233 (25%) patients, 2-5 cm in 420 (46%) patients, 5-10 cm in 171 (19%) patients, and >10 cm in 95 (10%) patients. Mesh was used in 79% of cases and varied in use from 53% of hernias <2 cm to 95% of hernias >10 cm. The most common mesh type was synthetic non-absorbable (46%), followed by synthetic absorbable mesh (37%). The incidence of complications was significantly associated with hernia width. CONCLUSIONS: A population-level, hernia-specific database captured operative details for 919 patients in 1 year. There was significant variation in mesh use and outcomes based on hernia size. These nuanced data may inform higher quality clinical practice.

Topological Structure Design and Fabrication of Biocompatible PLA/TPU/ADM Mesh with Appropriate Elasticity for Hernia Repair.

The meshes for hernia repair result in many problems that are related to complications including chronic pain and limited movement due to inadequate mechanical strength, non-absorbability, or low elasticity. In this study, degradable polylactic acid (PLA), synthetic thermoplastic polyurethane (TPU), and acellular dermal matrix (ADM) powders are combined to prepare a novel PLA/TPU/ADM mesh with three different topological structures (square, circular, and diamond) by 3D printing. The physicochemical properties and structural characteristics of mesh are studied, the results show that the diamond structure mesh with the pore size of 3 mm has sufficient elasticity and tensile strength, which provides the efficient mechanical strength required for hernia repair (16 N cm-1 ) and the value more than polypropylene(PP) mesh. Besides, in vitro and in vivo experiments demonstrate human umbilical vein endothelial cells could successfully proliferate on the PLA/TPU/ADM mesh whose biocompatibility with the host is shown using a rat model of abdominal wall defect. In conclusion, the results of this study demonstrate that the PLA/TPU/ADM mesh may be considered a good choice for hernia repair as its potential to overcome the elastic and strength challenges associated with a highly flexible abdominal wall, as well as its good biocompatibility.

Laparoscopic Ventral Hernia Repair with Poly-4-Hydroxybutyrate Absorbable Barrier Composite Mesh.

BACKGROUND: Repair of ventral and incisional hernias (VIHR) is a common procedure, newly introduced resorbable mesh biomaterials provide an attractive option to reduce the use of permanent synthetic mesh in hernia surgery and reduce its complications. However, data on the use of slowly resorbable mesh materials remains scarce, this study aims to evaluate the use of poly-4-hydroxybutyrate/absorbable barrier composite mesh (P4HB/ABCM) in laparoscopic repair of VIHR. METHODS: This is a retrospective study of a sequential cohort of patients undergoing laparoscopic VIHR utilizing a P4HB/ABCM mesh. Perioperative characteristics and clinical outcomes were collected. RESULTS: In total, 26 patients including 10 females and 7 males underwent laparoscopic VIHR using P4HB/ABCM. All surgeries were performed in a single institution by the same surgeon. The average patient age was 52.6, and the mean BMI was 35.5. All patients had a clean wound classification. The average defect size was 136.4 cm2. All patients were seen in clinic with a median follow-up of 28 months. We observed 4 wound seromas, and no wound infections or recurrences during the follow-up period. CONCLUSION: Results of laparoscopic VIHR with P4HB/ABCM are favorable and encourages further studies on the role of absorbable biosynthetic mesh materials in hernia surgery.

Early Clinical and Patient-Reported Outcomes of a New Hybrid Mesh for Incisional Hernia Repair.

INTRODUCTION: Consensus on the safety and efficacy of various types of mesh in reconstructing the abdomen has yet to be reached. Hybrid mesh products have been designed to address the need for a cost-effective mesh leveraging the tensile strength of a synthetic mesh while minimizing the prosthetic footprint within the abdominal wall through resorbable materials. In this study we evaluate early clinical outcomes and health related quality of life (HR-QOL) of a new Hybrid mesh, SynecorTM, for Ventral Hernia Repair (VHR). METHODS: Adult (>18 y old) patients undergoing VHR with SynecorTM mesh by a single surgeon between 2017-2019 with ≥1-y follow-up were identified. We analyzed a composite of postoperative outcomes as well as the incidence of hernia recurrence, readmissions, mortality, and HR-QOL. RESULTS: Thirty-five patients were included in our analysis with a median follow up of 2.1 y. The median age and BMI were 54.1 y and 33.2 kg/m2, respectively. The rate of surgical site occurrences was 37.1%, with only one patient (2.9%) requiring surgical intervention. No patients developed a hernia recurrence. Overall HR-QOL improved significantly (preoperative mean 2.5 [SD 0.7] versus postoperative 3.4 [0.4]; P< 0.01), particularly in regards to pain, functional status, self-esteem and body image (all P < 0.05). CONCLUSIONS: Abdominal reinforcement with SynecorTM mesh at the time of VHR results in promising early recurrence rates, an acceptable safety risk profile, and an improvement in overall HR-QOL.

Onlay Poly-4-Hydroxybutyrate (P4HB) Mesh for Complex Hernia: Early Clinical and Patient Reported Outcomes.

BACKGROUND: While mesh re-enforcement and advanced surgical techniques are cornerstones of complex ventral hernia repair (CVHR), the risk of complications and recurrence is common. We aim to evaluate the efficacy, safety, and patient reported outcomes (PROs) of patients undergoing CVHR with onlay Poly-4-hydroxybutyrate (P4HB). METHODS: Adult (>18 y old) patients undergoing VHR with P4HB (Phasix) in the onlay plane by a single surgeon from 01/2015 to 05/2020 were reviewed. VHR was considered complex if patients had significant co-morbidities, large abdominal wall defects, a history of extensive abdominal surgery, and/or concurrent intra-abdominal pathology. A composite of postoperative outcomes including surgical site occurrences (SSO), surgical site infection (SSI), and surgical site occurrences requiring procedural intervention (SSOpi), as well as PROs as defined by the Abdominal Hernia-Q (AHQ), were analyzed. RESULTS: A total of 51 patients were included with average age and body mass index of 56.4 and 29.9 kg/m2. Median follow up was 20 mo with a hernia recurrence rate of 5.9% (n = 3). 21 patients had an SSO (41.2%), 8 had an SSI (15.7%), and 6 had an SSOpi (11.8%). There was an association with Ventral Hernia Working Group ≥ 2 and development of SSO. There was a significant improvement in overall PROs (P < 0.0001) with no difference in those patients with and without complications (P > 0.05). CONCLUSION: For hernia patients with large defects and complex intra-abdominal pathology, a safe and effective repair is difficult. The use of onlay P4HB was associated with acceptable postoperative outcomes and recurrence rate.

Identifying predictors of ventral hernia recurrence: systematic review and meta-analysis.

BACKGROUND: Ventra hernias are increasing in prevalence and many recur despite attempted repair. To date, much of the literature is underpowered and divergent. As a result there is limited high quality evidence to inform surgeons succinctly which perioperative variables influence postoperative recurrence. This systematic review aimed to identify predictors of ventral hernia recurrence. METHODS: PubMed was searched for studies reporting prognostic data of ventral hernia recurrence between 1 January 1995 and 1 January 2018. Extracted data described hernia type (primary/incisional), definitions of recurrence, methods used to detect recurrence, duration of follow-up, and co-morbidity. Data were extracted for all potential predictors, estimates and thresholds described. Random-effects meta-analysis was used. Bias was assessed with a modified PROBAST (Prediction model Risk Of Bias ASsessment Tool). RESULTS: Screening of 18 214 abstracts yielded 274 individual studies for inclusion. Hernia recurrence was defined in 66 studies (24.1 per cent), using 41 different unstandardized definitions. Three patient variables (female sex, age 65 years or less, and BMI greater than 25, 30, 35 or 40 kg/m2), five patient co-morbidities (smoking, diabetes, chronic obstructive pulmonary disease, ASA grade III-IV, steroid use), two hernia-related variables (incisional/primary, recurrent/primary), six intraoperative variables (biological mesh, bridged repair, open versus laparoscopic surgery, suture versus mesh repair, onlay/retrorectus, intraperitoneal/retrorectus), and six postoperative variables (any complication, surgical-site occurrence, wound infection, seroma, haematoma, wound dehiscence) were identified as significant prognostic factors for hernia recurrence. CONCLUSION: This study summarized the current evidence base for predicting ventral hernia recurrence. Results should inform best practice and future research.