The introduction of biomaterial mesh had revolutionized the field of abdominal wall closure [13
]. Broadly grouped, biomaterial mesh is either human allograft or xenograft and dermal or non dermal in origin. Specific guidelines for specific biomaterial mesh selection for a given case remain to be defined; however in general it is accepted that for complex and contaminated cases, biomaterial mesh offers a viable substitute to the patient's own tissue. In particular the use of biomaterial mesh has been described to be clinically meaningful when the host native abdominal fascia is insufficient for closure without tension, ie (loss of abdominal domain), when there is a lack of viable tissue and a components separation is not technically feasible, or the field is contaminated or potentially contaminated and permanent synthetic mesh is relatively contraindicated [15
]. Biomaterial meshes are known to be resistant to infection[16
] and overcome the limitations of synthetic mesh for use in contaminated or potentially contaminated wounds, provide a tissue remodeling matrix, for host tissues and fibroblasts [17
]. In this series, the potential role of biomaterial mesh as adjuvant to abdominal wall closure in the setting of significantly potential impaired abdominal wall wound healing following HIPEC, with or without prior incisional hernia or after cytoreductive surgery of abdominal wall metastatic implants was investigated. In cases, there was a clinical indication for mesh reinforcement due to weakened, lacking or non viable abdominal wall fascia; the choice of biomaterial mesh was supported by the presence of potential contamination or frank contamination subsequent to a procedure entering the gastrointestinal tract.
Surgisis mesh was utilized in all open HIPEC procedures. This biomaterial mesh is composed of lyophilized porcine small intestinal submucosa, is known to attract cells to the wound area and signaling surrounding tissues to grow across the scaffold [18
]. The choice of this particular biomaterial mesh was based on the senior authors previous published experience with Surgisis [14
]as well as the reports of others observing that Sugisis remodels into vascularized host tissue [17
], thus allowing resistance to infection. Additionally, Surgisis is predominantley composed of collagen rather than elastin compared to dermal-based biomaterials; thus it is expected to result in less abdominal diathesis or hernia recurrence overtime [20
All Surgisis meshes were placed in underlay position with a minimum of a bilateral 3 cm fascial overlap-closure using absorbable number one PDS transfascial sutures placed circumferentially no more than two cm apart. Underlay repairs, such as Rivers-Stoppa retro-rectus repair, have been reported to result in improved recurrence rate and allow for re-approximation of the midline, thus potentially improving the mechanical function of the abdominal wall [21
The HIPEC protocol employed was the well-described regimen of single agent (Mitomycin C) at a dose (15 mg q 45 minutes x2) with a cumulative dwell time of 90 minutes, for all patients regardless of the origin of the primary malignancy and the body surface area of the patient [23
]. The present protocol does not include a measurement of serum Mitomycin C levels thus we are unable to discuss its pharmakodynamics in this setting, these data have been previously described by others [24
]. Postoperatively, none of the patients in this series developed neutropenia which has reported to occur in up to 39% of HIPEC patients using Mitomycin C at a higher dose[26
]. It should be emphasized that though there are multiple series reporting the use of different chemotherapeutic agent (s) and different doses during HIPEC, there is no consensus statement or general agreement on a single universal protocol. Currently, efforts are undergoing to create a registry database for all active HIPEC programs in USA allowing outcome analysis to elucidate this still evolving topic.
Seven of eight patients included in this study did not develop abdominal wall or bowel/intra-abdominal morbidities postoperatively and were discharged home after a mean length of stay of eight days. A single patient did sustain the complication of suspicious for enterocutaneous fistula wound discharge with associated with respiratory failure 7 days after HIPEC necessitating re-exploration. Upon re-exploration, the integrity of the abdominal wall and gastrointestinal were verified. The Surgisis mesh was found intact and the bowel was easily dissected from the mesh as has been previously described in experimental models [27
]. At operation, the patient was found to have extensive tumor necrosis from unresectable pelvic mass; because of potential compromised rectal wall, a loop diverting ostomy was created. The abdominal wall fascia was closed again with a new Surgisis mesh to prevent evisceration. Not unexpectedly, the native fascia later dehisced, and the patient developed and enterocutaneous fistula, however, the new Surgisis mesh was allowed to granulate and subsequently remodeled, allowing non surgical management.
Subsequent to HIPEC, perioperative abdominal wall and bowel/intra-abdominal complications may require surgical exploration [10
]. In this population re-exploration carries a high risk to both the abdominal wall recently exposed to hyperthermic chemotherapy and the bowel is usually firmly adherent to the abdominal with associated evisceration and/or the formation of enterocutaneous fistulae. The use of synthetic mesh as adjuvant to abdominal wall closure in such circumstances is contraindicated due to the potentially infected and contaminated environment.
The authors would emphasize the limitations of this study. This series represents early results of an abdominal wall reconstructive technique that in our experience was found to be safe and effective in preventing abdominal wall complications in a cohort of patients at high risk in the short term postoperative period. However, this report represents the experience of a single institution with a modest cohort and a short follow up. Long term follow up is needed before complete success for the use of biomaterial mesh can be declared to more define the role for biomaterial mesh in treatment and prevention of surgical site hernia following HIPEC and cytoreductive surgery. This may be limited by the inherent limited survival of many patients with disseminated peritoneal malignancy.
In this small series biomaterial mesh was applied at the end of all CRS-HIPEC procedure and showed a beneficial effect in minimizing early postoperative abdominal wall complications. However, extrapolating these results to be applied to all CRS-HIPEC patients as a universal approach will probably reveal that only a group of high risk patients including those with multiple abdominal wall surgeries, preoperative abdominal wall hernia or metastatic implants to the abdominal wall will benefit from such approach.
The selection of Surgisis mesh, was based on results of other studies reporting its resistant to infection and total remodeling in settings other than HIPEC. It will be necessary to document remodeling in this setting by histopathology incorporating tissue samples during the various stages of wound healing at distinct intervals after HIPEC with and without Surgisis mesh abdominal wall reconstruction.
Finally, the HIPEC protocol used only Mitomycin C as single agent chemotherapy. Although, chemotherapeutic agents share an inhibitory effect on wound healing, it is possible, although not yet investigated that in the setting of HIPEC, that this known inhibitory effect varies significantly between different agents.