Key words : Abdomen, Reconstruction, Repair, Wound

Introduction

Incisional hernias may occur after any abdominal operation, and the overall incidence of an incisional hernia after abdominal operations is 2% to 13%.^1-3 Incisional hernias develop in 10% patients who subsequently develop a wound infection.¹ The risks of fascial dehiscence, wound infection, and incisional hernias are higher in organ recipients than they are in other patients.⁴ According to a previous report in renal transplant recipients, 4.8% patients developed wound infections and 3.6% patients had a fascial dehiscence or incisional hernia.⁵ More than 50% incisional hernias occur within 6 months after surgery.¹ Several risk factors have been defined including obesity, wound infection, hematoma, urinoma, lymphocele, repeat interventions, immuno­suppression, diabetes mellitus, advanced age, malnutrition, and smoking history.^1,3

The main principle of incisional hernia repair is to restore the anatomic and physiologic integrity of the abdominal wall.² Fascial defects with diameter < 6 cm can be repaired primarily, but 30% to 50% defects > 6 cm recur after primary closure.² Several types of prosthetic mesh currently are available for hernia repair.⁶ Although permanent mesh prostheses are considered the best treatment for minimizing hernia recurrence, they have been associated with a high risk of complications due to their nonabsorbable characteristics such as erosion into the abdominal viscera, protrusion, extrusion, adhesion, infection, and bowel fistulae that can lead to more complex and costly surgery.⁷

Biological mesh was introduced as an alternative to synthetic mesh in the 1990s.⁶ There are 15 different bioprosthetic materials taken from different types of tissue.⁷ Biological mesh prostheses allow neo­vascularization and regeneration due to infiltration of native fibroblasts and they are incorporated into the surrounding tissue.^6,8 During incorporation, they gradually are degraded and generate a new, metabolically active neofascia to withstand the mechanical forces of the abdominal wall.^7,8

The use of synthetic mesh in transplant patients is controversial. Simple, small, and noninfected incisional hernias may be repaired either primarily or with polypropylene mesh with good results.³ Large cases of fascial dehiscence requiring abdominal reconstruction rarely are discussed in the literature, and no clear treatment method exists for giant incisional hernias in transplant patients. Recent studies have shown that biological prostheses have a greater ability to integrate into tissues, resist bacterial colonization, and reduce cytotoxic or allergic reactions, and provide similar functional results, compared with synthetic prostheses.⁹ Biological prostheses do not require any reduction or discontinuation of immunosuppressive therapy.⁹

The purpose of this case report was to present a kidney and pancreas transplant recipient who had a giant incisional hernia that was treated successfully with a biological prosthesis.

Case Report

A 40-year-old male kidney and pancreas transplant recipient was admitted to the hospital with a giant incisional hernia. He received a left living-donor kidney transplant 7 years earlier and a pancreas transplant 2 years earlier. The giant abdominal incisional hernia occurred within 6 months after the pancreas transplant. The major risk factors were obesity, diabetes mellitus, and immunosuppressive therapy. The patient’s immunosuppressive therapy included cyclosporine, mycophenolate mofetil, and steroids. Physical examination showed that the defect was 40 cm (vertical) × 30 cm (horizontal). We decided to use a porcine dermal collagen implant to facilitate abdominal wall closure.

The operative procedure started with excision of the scar. The hernia sac was opened carefully, adhesions were gently removed, and dissection was continued inside, to 5 cm in all directions. The sac was excised along the edge of the defect. The 2 porcine dermal collagen mesh prostheses (40 × 20 cm and 30 × 20 cm) (Permacol, Covidien, Mansfield, MA, USA) were sutured to each other, positioned without tension to the edges of the fascia defect, and sutured with 1-0 interrupted polypropylene sutures (Figure 1). We placed 2 Jackson-Pratt drains (Cardinal Health, Dublin, OH, USA) between the mesh construct and abdominal skin. Subcutaneous tissue and skin were closed with interrupted sutures. Antibiotics were given until postoperative day 5. The patient continued immunosuppressive therapy without any changes. Drains were removed and the patient was discharged on postoperative day 5 without complications. No seroma, hematoma, or wound infection occurred after the operation.

An abdominal magnetic resonance imaging scan at 1 year after surgery showed complete integrity of the biological prostheses, and the patient had an excellent functional result (Figure 2). No hernia recurrence was observed at 2-year follow-up after surgery.

Discussion

Incisional hernia is a predominant complication in transplant recipients. The incidence of incisional hernias is much higher in patients receiving a combined kidney and pancreas transplant than kidney transplant alone.¹

It has been claimed that permanent synthetic mesh is safe in renal recipients but there is an increased risk of infection.1 Inorganic materials are passive, rigid, and adynamic, and they restore the structure but not the function of the abdominal wall.² Moreover, inorganic materials are associated with foreign body complications.² Half of the patients who develop a recurrence have an infection, and transplant recipients have higher risks of the use of synthetic prostheses because of being immuno­suppressed.^1,9 Recent studies showed that biological prostheses provided similar functional results without complications compared with synthetic prostheses.^1,4,9

The prosthesis used in the present case (Permacol, Covidien) is a porcine-derived acellular dermal mesh, predominantly composed of type I collagen.⁶ After cell removal, it is sterilized by gamma irradiation and packaged in a hydrated state that makes it usable immediately without any pre­paration.⁸ This prosthesis is treated with hexa­methylene diisocyanate to increase collagen cross-linking and decrease biodegradability, which might be accelerated in contaminated wounds.^6,8 Porcine dermis is the closest to human dermis and it is not cytotoxic, hemolytic, pyrogenic, or allergenic, and it does not elicit a foreign body response.¹⁰ It is colonized by host tissue cells and blood vessels that minimize the risk of infection.¹⁰ It is soft and flexible, and it has bilateral smooth surfaces with high tensile strength.¹⁰ It is sold in sheets, allowing it to be cut to shape, and provides the largest grafts available (maximum size, 28 × 40 cm).^8,10

In animal studies, a porcine dermal collagen implant produced a substantially weaker inflam­matory response and less extensive, less dense adhesions.^10-12 Although it had significantly lower tensile strength than polypropylene at 30 days after being implanted, at 90 days there was no statistically significant difference.^10,11 Within 12 weeks after being implanted, biological materials were filled with a regenerated tissue that resembled normal fascia.²

Biological mesh is widely used in nontransplant patients. Recurrence rates vary from 0% to 15% in recent reviews, but recurrence rate was lower (2.9%) in clean and clean-contaminated cases and increased with the extent of contamination.^6-8 Infection was the most common complication with an overall rate of 15.9%, but infection rate with the mesh used in the current study (Permacol, Covidien) was 6.1%.⁸ Grafts were removed in only 4.9% infected cases.⁸ A meta-analysis of open incisional hernia repair with synthetic mesh showed that a quarter of infections required mesh removal.¹³ Biological grafts were associated with a high salvage rate in cases of infection compared with synthetic grafts.⁸ The major advantage of biological over synthetic implants is that biological grafts can be used in direct contact with bowel without causing fistulas, and they cause minimal adhesions with successful results even in contaminated or infected wounds.^10,14

The operative strategy of incisional hernias in transplant patients is controversial. Recurrence rates vary from 2% to 20% in studies of hernia repair with prosthetic mesh in renal transplant recipients.^15,16 There are limited data about the use of biological prostheses in transplant patients who have incisional hernias. Coccolini and coworkers reported a 14.3% recurrence rate and 28.6% complication rate.⁴ The mean overall complication rate of incisional hernia repair with biological prostheses in the current literature was 9.4% according to their review.⁴ Santangelo and associates reported a series of 10 transplant patients with incisional hernia repair using a biological prosthesis without complications or hernia recurrence.⁹ Pentlow and coworkers reported satisfactory functional results in 5 pediatric renal transplant recipients with donor size discrepancy who had abdominal wall closure assisted with porcine dermal collagen implants.¹⁰

In our preliminary experience, a biological prosthesis appears useful, safe, and effective for incisional hernia repair in transplant patients and provides excellent functional results. Major advantages of biological compared with synthetic prostheses include a greater potential to integrate into host tissues, resist bacterial colonization, reduce cytotoxic or allergic reactions, and not to require any reduction or discontinuation of immunosuppressive therapy. In our opinion, biological prostheses are safer, more effective, and more reliable than synthetic prostheses, especially for large incisional hernias in transplant recipients. We believe that further larger studies can support our opinion.

References:

1. Chang EI, Galvez MG, Padilla BE, Freise CE, Foster RD, Hoffman WY. Ten-year retrospective analysis of incisional herniorrhaphy following renal transplantation. Arch Surg. 2011;146(1):21-25.
2. Tuveri M, Tuveri A, Nicolò E. Repair of large abdominal incisional hernia by reconstructing the midline and use of an onlay of biological material. Am J Surg. 2011;202(1):e7-e11.
3. Lo Monte AI, Damiano G, Maione C, et al. Use of intraperitoneal ePTFE Gore Dual-Mesh Plus in a giant incisional hernia after kidney transplantation: a case report. Transplant Proc. 2009;41(4):1398-1401.
4. Coccolini F, Catena F, Bertuzzo VR, Ercolani G, Pinna A, Ansaloni L. Abdominal wall defect repair with biological prosthesis in transplanted patients: single center retrospective analysis and review of the literature. Updates Surg. 2013;65(3):191-196.
5. Humar A, Ramcharan T, Denny R, Gillingham KJ, Payne WD, Matas AJ. Are wound complications after a kidney transplant more common with modern immunosuppression? Transplantation. 2001;72(12):1920-1923.
6. Smart NJ, Marshall M, Daniels IR. Biological meshes: a review of their use in abdominal wall hernia repairs. Surgeon. 2012;10(3):159-171.
7. Bellows CF, Smith A, Malsbury J, Helton WS. Repair of incisional hernias with biological prosthesis: a systematic review of current evidence. Am J Surg. 2013;205(1):85-101.
8. Slater NJ, van der Kolk M, Hendriks T, van Goor H, Bleichrodt RP. Biologic grafts for ventral hernia repair: a systematic review. Am J Surg. 2013;205(2):220-230.
9. Santangelo ML, Carlomagno N, Spiezia S, et al. Use of biological prostheses in transplant patients with incisional hernias. Preliminary experience. Ann Ital Chir. 2013;84(4):471-475.
10. Pentlow A, Smart NJ, Richards SK, Inward CD, Morgan JD. The use of porcine dermal collagen implants in assisting abdominal wall closure of pediatric renal transplant recipients with donor size discrepancy. Pediatr Tranplant. 2008;12(1):20-23.
11. Zheng F, Lin Y, Verbeken E, et al. Host response after reconstruction of abdominal wall defects with porcine dermal collagen in a rat model. Am J Obstet Gynecol. 2004;191(6):1961-1970.
12. Kaleya RN. Evaluation of implant/host tissue interactions following intraperitoneal implantation of porcine dermal collagen prosthesis in the rat. Hernia. 2005;9(3):269-276.
13. Forbes SS, Eskicioglu C, McLeod RS, Okrainec A. Meta-analysis of randomized controlled trials comparing open and laparoscopic ventral and incisional hernia repair with mesh. Br J Surg. 2009;96 (8):851-858.
14. Parker DM, Armstrong PJ, Frizzi JD, North JH Jr. Porcine dermal collagen (Permacol) for abdominal wall reconstruction. Curr Surg. 2006;63(4):255-258.
15. Kieszek R, Wszola M, Domagała P, Chmura A. Current trends in the treatment of incisional hernia in patients after kidney transplantation [in Polish]. Pol Merkur Lekarski. 2010;29(169):50-53.
16. Varga M, Matia I, Kucera M, Oliverius M, Adamec M. Polypropylene mesh repair of incisional hernia after kidney transplantation: single-center experience and review of the literature. Ann Transplant. 2011;16(3):121-125.