Analysis and Characterization of Biologic Implants

Several such biologic meshes have now been developed and marketed for use in hernia repair
and soft tissue reconstruction. These biologics include one product derived from porcine
intestinal submucosa (SurgisisTM, Cook Medical), another derived from porcine dermis
(CollaMendTM, C.R. Bard Inc.) and several others derived from decellularized human dermis,
such as AlloDermTM (LifeCell Corp.), AlloMaxTM (C.R. Bard Inc.), and FlexHDTM
(Musculoskeletal Transplant Foundation). Although similar in concept and design, each of
these biologic meshes is produced in a distinct, proprietary fashion, and different
techniques are used by each company in the processing and storage of their respective
products. Given that these processing steps are protected industrial intellectual property,
rigorous comparison of the performance of each mesh is very difficult. It is expected that
certain methods, such as employing or avoiding chemical cross-linking of the ECM proteins,
would lead to significant differences in cell migration into, and biochemical remodeling of
each individual mesh. These differences may be of particular importance in the scenario of
laparoscopic ventral hernia repair, where the mesh is placed in direct apposition to the
parietal peritoneum. In this case, if the biologic were to remodel and take on more of the
properties of the distensible peritoneum rather than that of the stronger abdominal wall
fascia, this could have a significant impact on the long-term strength and durability of the
hernia repair. A similar situation could also be foreseen to occur at the esophageal hiatus
and/or the site of an intestinal stoma. We feel that it is thus important to study the
remodeling processes that these meshes undergo over time and determine if differences in
product processing or anatomical position have any effect on mesh incorporation and hernia
integrity. Many of these meshes have already been used in human subjects, yet a certain
number of these patients are known have suffered hernia recurrences requiring reoperation and
removal of some or all of the original mesh prostheses. It is our belief that these biologic
explants represent an excellent source of material to study the remodeling process over
numerous given time points and at various anatomic locations. We feel it is also important to
compare the explanted biologic meshes to "control" tissues, to examine how successfully the
biologic meshes are mimicking native tissue at the molecular and histologic level. To
eliminate confounding factors, explanted meshes will be compared to biopsies of abdominal
wall fascia from patients undergoing non-hernia related surgical procedures.

Inclusion Criteria:

- All patients undergoing a repeat operation to repair a recurrent hernia or revise a
surgical site which has been previously repaired using one of the aforementioned
biologic meshes. Any patient undergoing a surgical procedure where fascial biopsy
would not compromise the integrity of the procedure.

Exclusion Criteria:

- For those subjects meeting the inclusion criteria, the only population that will be
excluded is that of prisoners.