Ventral Hernia Reconstruction with GORE ENFORM Biomaterial

Abstract

Introduction: Ventral hernia repair (VHR) is one of the most common surgeries performed in the United States. Degradable mesh is the recommended choice for patients presenting with high-risk co-morbidities or increased risk for infection. GORE® ENFORM Biomaterial^TM is a biosynthetic degradable mesh that has recently been approved for use in ventral hernia reconstruction with no reports of its clinical outcomes. Methods: This study was a single surgeon case series. Patients were included in the study if they underwent VHR with GORE^® ENFORM Biomaterial^TM. The decision to use GORE® ENFORM Biomaterial^TM was the senior surgeon’s decision based on the patient's center for disease control classification. Patient comorbidities, hernia characteristics, postoperative hernia recurrence, and surgical site occurrences (SSOs) were collected at in-patient follow-up appointments and chart review. Patients were asked to complete preoperative and postoperative patient-reported outcomes (PROs) using the Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Intensity short form 3a and the hernia-specific quality of life (HerQLes) survey. Results: A total of 15 patients were included in this study. The average length of follow-up was 315 days. Postoperatively, 26.7% of patients had an SSO with 4 surgical site infections. Two patients required an operative washout with mesh removal. One patient experienced hernia recurrence. Eight of the 15 patients completed preoperative and postoperative PROs. Conclusion: This is the first clinical study to report the outcomes of ventral hernia repair using ENFORM mesh. These results show that Enform mesh is an option to consider in complex ventral hernia reconstruction.

Introduction

Ventral hernia repair (VHR) is one of the most common surgeries performed in the United States with estimated total annual costs greater than $3 billion dollars and more than 340 000 surgeries performed annually. ¹ Utilization of mesh in VHR is associated with 50% lower rates of hernia recurrence.^2–4 Despite the benefits of mesh, a major adverse event is mesh infection, particularly with nondegradable meshes made from polypropylene, polyester, polyvinylidene fluoride, and expanded polytetrafluoroethylene. ⁵ While mesh infection may be successfully managed with antibiotics, in select cases, the mesh has to be removed and this can be a tedious process. ⁶ To overcome mesh infection-related complications, degradable meshes (ie, human allografts and animal xenografts) were first introduced in the 1980s.^7,8 The concept behind these meshes is that they purportedly do not require removal if they become infected since they degrade in the presence of bacterial enzymes.^6,9,10 Some acute postoperative infections may still require partial or total mesh removal. Given the plethora of mesh options, in 2010, the ventral hernia working group (VHWG) outlined a classification system for patients at risk for VHR complications and accordingly provided recommendations for mesh selection. ¹¹ Degradable mesh was recommended for patients that met the criteria for grades 2 to 4. A major drawback of degradable mesh is that they are less effective at preventing hernia recurrence because they do not significantly enhance wound-breaking strength after they degrade. ⁶

Biosynthetic degradable absorbable mesh is a newer form of a degradable mesh that is made from synthetic materials (similar to synthetic degradable sutures) that undergo breakdown and absorption via hydrolysis. ¹² There is evolving literature regarding the durability of biosynthetic mesh for preventing ventral hernia; the data is nascent.^6,13 Currently, there are 5 different biosynthetic meshes on the US market including Polyglactin 910 Mesh (Vicryl), Phasix^TM (trademark of C.R. Bard), comprised of poly-4-hydroxybutyrate monofilament fibers, TIGR Matrix^TM (Novus Scientific Pte Ltd), Gore BIO-A^TM (W. L. Gore & Associates, Inc), and GORE® ENFORM Biomaterial^TM.^14–18 Gore BIO-A^TM is made up of a combination of polyglycolic acid-trimethylene carbonate. A newer version with specialized processing is called GORE® ENFORM Biomaterial^TM.^19,20

GORE^® ENFORM Biomaterial^TM is comprised of polyglycolic acid and trimethylene carbonate copolymer. The advantage of GORE^® ENFORM Biomaterial^TM is it has a prominent texture surface, slightly smaller fiber, and is more pliable compared to BIO-A. ²¹ This pliability provides easier handling by surgeons and better tissue incorporation. Since GORE^® ENFORM Biomaterial^TM is relatively new to the market, there are no reports of GORE^® ENFORM Biomaterial^TM in VHR. The purpose of this article is to review the senior author (HL) experience with GORE® ENFORM Biomaterial^TM. This report includes patient demographics, classification schemata, and surgical and patient-reported outcomes.

Methods and Materials

This study was a single surgeon case series. The methods and collection of variables were approved by our institutional review board. Patients were included in this study if they underwent VHR with GORE^® ENFORM Biomaterial^TM. The surgeon's decision to use GORE^® ENFORM Biomaterial^TM in the ventral hernia repair was based on CDC classification. Surgical dates spanned from December 2018 to December 2020. Data collection was performed through chart review and designed to mirror the variables collected by the Abdominal Core Health Quality Collaborative (ACHQC) data registry. The ACHQC is a nonprofit collaborative that collects aggregate health information related to abdominal health including hernia repair surgery.

All patients were referred to physical therapy pre- and postoperatively but follow-up was at the patient’s discretion. Patients that were evaluated by physical therapy were instructed to complete a 12-week regimen designed specifically for hernia repair and core strengthening. Similar to the ACHQC, data was obtained in the preoperative and postoperative settings. Patients were scheduled to follow-up at 2 weeks, 1 month, 6 months, and 1 year in a clinic. Patients were evaluated preoperatively and sent to appropriate referrals, as feasible. Preoperative goals included hemoglobin A1c (HA1c) less than 8.0, body mass index (BMI) less than 35, smoking cessation, and nutrition referral for poor nutritional markers.

Patients were evaluated postoperatively for hernia recurrence, surgical site occurrence (SSO), or surgical site infection (SSI). SSI was diagnosed via clinical judgment by the operative surgeon and classified into superficial, deep, or organ space infection. SSO included any surgical site infection, but also included wound cellulitis, nonhealing incisional wound, fascial disruption, skin or soft tissue ischemia, skin or soft tissue necrosis, wound serous or purulent drainage, stitch abscess, seroma, hematoma, infected or exposed mesh, or development of an enterocutaneous fistula (ECF). A serious adverse event (SAE) was defined as any patient death or life-threatening complication. For long-term evaluation of patients, a chart review was performed to identification of long-term occult SSO.

In addition, patients were evaluated for patient-reported outcomes (PROs) in person or via phone or email prior to and after surgery. The Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Intensity short form 3a and the hernia-specific quality of life (HerQLes) survey are validated tools used to assess VHR-specific outcomes since this is part of the ACHQC measures. The PROMIS raw scores were then converted to their corresponding T-scores using the calculator available on Health Measures net. ²² The lower T-score refers to improved status and less pain with higher scores referring to worse quality of life secondary to pain. The HerQles raw score was converted to a 100-point scale as was described in its initial implementation. ²³ Higher scores are indicative of the higher quality of life for the HerQles results.

Surgical Technique

At the authors’ institution, complex ventral hernias were done in conjunction with other surgical teams including general surgery, colorectal surgery, hepatobiliary surgery, and urology. The surgical teams performed primary indicated procedures including lysis of adhesions (LOA), ostomy takedown or creation, bowel resection, cancer resection, or ECF repair. Following completion of this primary surgical indication, the plastic surgery team performed hernia reconstruction.

After LOA was completed, the defect was analyzed to determine if primary fascial closure could be obtained under minimal tension. If, however, the fascial edges could not be reapproximated without tension, anterior component separation was added and care was taken to preserve cutaneous perforators during dissection. Mesh reinforcement was then used in an overlay, retrorectus, or underlay position, as the surgeon has had good outcomes with all techniques. If the rectus fascia could not be reapproximated, a bridging mesh repair was performed. Two 15 French surgical drains were placed for all cases exiting at the inferior aspect of the abdomen in the suprafascial plane. Drains were removed after output was less than 30 mL for 2 consecutive days.

Results

A total of 15 patients underwent abdominal wall reconstruction with GORE^® ENFORM Biomaterial^TM. Table 1 outlines the patient demographics, past medical history, and surgical outcomes. The cohort genders were evenly split with 8 males and 7 females. Patient ages ranged from 53 to 78 years old with a mean age of 69 years old. The BMI of the cohort was ∼30.8. All presenting patients had significant presenting co-morbidities. Nine patients had a colostomy, ileostomy, or ECB at the index surgery. Inflammatory bowel disease (IBD) was present in 4 patients. An additional 4 patients previously had undergone abdominal radiation due to a history of cancer. None of the patients were VHWG Grade 1. One patient was VHWG Grade 2. A total of 12 patients met the criteria for VHWG Grade 3 and 2 patients were characterized as VHWG Grade 4. One patient was considered a clean surgical wound. Seven patients were classified as clean-contaminated. Five patients were classified as contaminated wounds and 2 patients met the criteria for the dirty or infected surgical sites. Hernia width ranged from 5 to 20 cm in size with an average width of 10.1 cm.

Table 1.

Ventral Hernia Enform Repair Patients.

Patient	Age gender	BMI	Comorbidities	Wound status	VHWG classification	Additional surgery performed	Hernia width (cm)	Hernia length (cm)	Component separation	Mesh placement	SSO	Outcome	Follow-up (days)
Patient 1	72 M	30.39	Radiation	Contaminated	Grade 3	LOA, abdominal wall resection, cancer resection, bowel resection	16	10	No	Underlay	No	Well healed from hernia surgery. Eventual death related to cancer	68
Patient 2	71 F	23.11	IBD, Smoker, enterocutaneous fistula	Dirty/infected	Grade 4	ECF takedown, Bowel Resection	9	20	Unilateral	Bridging Onlay	Yes	Peri-rectal fluid collection requiring percutaneous drain. Eventual death secondary to GIB	48
Patient 3	69 F	31.60	Colostomy, HTN	Clean-contaminated	Grade 3	LOA, ostomy takedown	6	25	Bilateral	Onlay	Yes	SSI requiring PO abx	320
Patient 4	71 F	28.73	Colostomy, COPD, Anti-coagulation, HTN	Contaminated	Grade 3	LOA, ostomy takedown	10	25	Bilateral	Onlay	No	Well healed	455
Patient 5	64 M	37.80	HTN, Antiplatelet, Obesity	Clean-contaminated	Grade 3	LOA, ileal Conduit	10	30	Bilateral	Onlay	No	Well healed	351
Patient 6	53 F	23.99	Malnourished	Clean	Grade 2	LOA, Cancer resection	5	23	Bilateral	Onlay	No	Well healed	282
Patient 7	70 F	28.87	Diabetes, Antiplatelet, IBD, HTN	Clean-contaminated	Grade 3	LOA, Bowel Resection	16	20	No	Retrorectus	No	Well healed	432
Patient 8	78 M	23.39	Radiation	Contaminated	Grade 3	Cancer Resection, Ileal Conduit	8	30	Bilateral	Onlay	No	Well healed	443
Patient 9	55 F	30.42	Ileostomy, enterocutaneous fistula	Dirty/infected	Grade 4	LOA, ECF takedown	15	25	No	Bridging Onlay	No	Well healed	213
Patient 10	72 M	22.68	Colostomy	Contaminated	Grade 3	LOA, Bowel Resection	5	25	Bilateral	Underlay	No	Well healed	369
Patient 11	66 M	34.15	Radiation	Clean-contaminated	Grade 3	LOA, Bowel Resection, Ileal Conduit	7	30	Bilateral	Onlay	No	Well healed	511
Patient 12	57 M	28.03	HTN, Anti-coagulation, IBD, Ileostomy	Clean-contaminated	Grade 3	LOA, Bowel resection, ostomy takedown	9	25	Bilateral	Onlay	Yes	Postop infection requiring OR washout with mesh removal	176
Patient 13	68 F	49.47	Diabetes, radiation, colostomy, obesity	Contaminated	Grade 3	LOA, Bowel Resection, Ileal Conduit	20	35	No	Bridging Onlay	Yes	Postop infection requiring OR washout with partial mesh removal, Hernia Recurrence	431
Patient 14	65 M	30.42	Colostomy	Clean-contaminated	Grade 3	LOA, Bowel Resection	10	30	Bilateral	Onlay	No	Well healed	415
Patient 15	67 M	38.87	IBD, malnutrition, enterocutaneous fistula	Clean-contaminated	Grade 3	LOA, ECF takedown	5	7	No	Onlay	No	Well healed	212

Abbreviations: SSO, surgical site outcome; BMI, body mass index; PRO, patient-reported outcomes; GIB, gastrointestinal bleed.

All hernia surgeries were done in conjunction with additional surgical teams including general surgery, urology, and hepatobiliary service. All patients underwent LOA. Bowel resection was performed in 8 patients and 6 patients had ostomy or ECF reversal. Three patients also underwent oncologic resection at the time of hernia reconstruction. A component separation was included in 10 of 15 patients. Nine patients received an onlay mesh reconstruction. Two patients were reconstructed with underlay and retrorectus mesh placement was used for one patient. Three patients were unable to achieve primary fascial closure and had bridging mesh placed in an onlay position.

Table 2 outlines the postoperative outcomes of the 15 patients that underwent hernia reconstruction. Eleven patients recovered well postoperatively without any SSO. Two patients died in the perioperative period. One patient died from underlying malignancy, but had no additional postoperative complications and another died from postoperative gastrointestinal bleed unrelated to surgical repair. Four patients had SSOs postoperatively with surgical site infections. The depth of infection varied including a superficial soft tissue infection, 2 deep incisional infections involving mesh, and a deep space peritoneal infection not involving mesh. Two patients returned to the operating room requiring mesh explantation for infection and lack of incorporation. One patient experienced a recurrence of hernia following mesh explantation. Postoperative follow-up ranged from 48 to 511 days with a mean follow-up of 315 days.

Table 2.

Surgical Site Outcomes.

Postoperative outcome		Number of patients
Surgical site occurrence		4 (26.7%)
SSO type
	Wound cellulitis	2 (13.3%)
	Nonhealing incisional wound	0
	Seroma	0
	Purulent drainage	1 (6.7%)
	Hematoma	0
	Infected mesh	2 (13.3%)
	Intra-peritoneal abscess	1 (6.7%)
Surgical site infection		4 (26.7%)
	Superficial infection	1 (6.7%)
	Deep incisional infection	2 (13.3%)
	Deep space Infection	1 (6.7%)
Treatment for SSO
	Oral antibiotics	1 (6.7%)
	IV antibiotics	3 (20%)
	Operative washout	1 (6.7%)
	Mesh removal	2 (13.3%)
Perioperative death		2 (13.3%)
Hernia recurrence		1 (6.7%)

Table 3 demonstrates the scores of the patients that completed the PROMIS pain survey and HerQles PROs. Eight of the 15 patients completed preoperative and long-term postoperative PROs. Four of the patients, #5, #6, #11, and #13, had an overall similar or unchanged PROMIS and HerQles score. Two patients, #1 and #4 had lower or worse HerQles scores at 1-year postoperatively. Finally, 2 patients, #8 and #12 had much improved PRO scores at the 1-year postoperative mark.

Table 3.

Patient Reported Outcomes.

	Preop		Postop
	Promis 3a pain	HerQles	Promis 3a pain	HerQles
Patient 1	48	62	72.8	12
Patient 2	36.3	100	–	–
Patient 3	81.9	8	–	–
Patient 4	36.3	95	36.3	65
Patient 5	68.4	30	68.4	35
Patient 6	36.3	20	36.3	23
Patient 7	36.3	37	–	–
Patient 8	61.1	22	36.3	100
Patient 9	–	–	36.3	92
Patient 10	–	–	58.9	90
Patient 11	36.3	7	48	12
Patient 12	57.2	12	36.3	63
Patient 13	69.4	20	70	20
Patient 14	–	–	–	–
Patient 15	–	–	44	80

Discussion

The majority of patients in this study had a complex past medical histories and abdominal wall issues that placed them in VHWG 3 or 4 and CDC classification for clean-contaminated or contaminated. The overall SSO rate for this patient population was 26.7%. Further breakdown of the outcomes demonstrated that half of those SSOs were mesh related. Two patients required mesh explantation secondary to infection. The other 2 patients had an infection that was intraperitoneal and superficial without any need for mesh explantation. The surgical mesh removal for these patients was only partial with only unincorporated mesh removed. All of the patients underwent abdominal wall reconstruction as a secondary procedure in conjunction with an index surgical procedure including LOA, cancer resection, ECF and ostomy takedown, bowel resection, or ileal conduit creation. In many cases, patients were taken to the operating room to prevent further progression of disease and could not reach BMI (< 35), smoking cessation, or nutrition (HA1c < 8 for diabetics) preoperative goals. Multiple studies have demonstrated that patients presenting these comorbidities are at higher risk of worse surgical outcomes.^2,24 High-risk patients have an increased risk of SSOs and patients with permanent mesh results in difficult surgical explantation compared to absorbable mesh.^9,25,26

In addition, only one hernia occurrence was found postoperatively. The hernia recurrence rate was comparable to published data on similar patients with an analogous follow-up. ²⁷ Studies evaluating similar higher-risk patient populations report SSO of 20% to 28% in patients undergoing ventral hernia repair with mesh.^28,29 SSO is not specifically related to mesh reconstruction as infections still occur in patients who undergo VHR without mesh and the data suggests SSO rates are not higher with mesh.^30,31 These findings demonstrate that GORE^® ENFORM Biomaterial^TM is noninferior compared to other biosynthetic or biologic meshes 1 year postoperatively.

GORE^® ENFORM Biomaterial^TM has been commercially available for use since 2018. At present, it is one of 4 biosynthetic meshes available on the market. ¹² Biologic and biosynthetic mesh reconstructions have demonstrated reduced mesh-related SSO in VHWG 2 to 4 in multiple studies.^{5, 9} While there are clinical indications for use of biologic mesh in ventral hernia repair, there is a high associated cost with its use.^32,33 The use of biosynthetic mesh may offer some benefits associated with biologic mesh at a lower cost. ³⁴ This study presents the first clinical outcome data with GORE® ENFORM Biomaterial^TM. Further research is needed to better understand the safety profile and long-term performance of GORE® ENFORM Biomaterial^TM in hernia repair.

Eight of the 15 patients who completed preoperative and long-term postoperative patient-reported outcomes. This included the PROMIS pain Intensity short form 3a and HerQles abdominal wall patient-reported outcomes. The HerQles questionnaire is a validated tool that specifically evaluates patients’ quality of life-related to their hernia reconstruction. ²³ Overall, 2 patients had improved outcomes, 4 had an equivalent, and 2 had lower scores of the HerQles outcomes. In total only 5 patients were able to complete the postoperative physical therapy regimens. These limited findings suggest that evaluation of postoperative clinical outcomes and SSO is not a complete evaluation of patient outcomes. A more comprehensive assessment of hernia reconstruction with PROs will guide future treatment. Uniform completion of preoperative and postoperative PROs is a challenging process. Of the 7 patients that did not complete both preoperative and postoperative PRO, 2 died in the postoperative setting, one was unable to be reached successfully for follow-up and four failed to complete preoperative PROs. A previous study demonstrated a long-term PRO peak response rate of 45%. ³⁵

There are several limitations to this study. This was a small patient cohort that limited the value of reported outcomes. In addition, it has been shown that hernia outcomes change based on longer follow-up studies. Both the patient sample size and mean follow-up of this study were limited by the short market availability of GORE® ENFORM Biomaterial^TM. ³⁶ Two of the 15 patients died in the early postoperative period which also contributed to reduced overall long-term follow-up. The patients had a wide array of presenting hernia characteristics. There was a small variety in approaches to hernia reconstruction tailored to each presenting patient, but the majority underwent onlay reconstruction. The ideal placement of mesh is contested with some advocating for retrorectus placement as the strongest repair. ³⁷ However, multiple additional studies support equivalent outcomes with onlay or underlay placement.^38,39

Conclusion

This is the first clinical study to report outcomes of ventral hernia repair using GORE^® ENFORM Biomaterial^TM. We conclude that GORE^® ENFORM Biomaterial^TM is an acceptable option to consider in complex ventral hernia repair and demonstrates similar outcomes to other commercially available biosynthetic or biological meshes used in ventral hernia repair. Further investigation is indicated to clarify the benefits and role of GORE^® ENFORM Biomaterial^TM in ventral hernia repair.