PATHOLOGICAL AND CLINICAL ASPECTS OF REPAIR OF LARGE INCISIONAL HERNIAS AFTER IMPLANT OF A POLYTETRAFLUOROETHYLENE PROSTHESIS

One of the alternatives for the repair of large incisional hernias is the use of a prosthetic material. The present retrospective study rela tes the experience acquired for treatment of large incisional hernias (hernial orifice > 10 cm) with ePTFE prostheses. Thirty-eight massive incisional hernias were repaired using ePTFE 1 mm thick Soft Tissue Pa tches. Twenty-four patients received a prosthetic patch of 10 x 15 cm, 13 a patch of 15 x 20 cm, and 1 a patch of 20 x 30 cm. In 30 cases th e ePTFE was sutured to the recipient tissues with a double row of poly propylene stitches. For the first eight interventions the ePTFE was se cured using a single row of polypropylene sutures. Pathologic studies of biopsies from patients who bad undergone surgical reintervention at 40 days, 12 months, and 48 months, respectively, were done using ligh t microscopy, scanning electron microscopy, and immunohistochemistry w ith human antimacrophage antibodies KP-1. The follow-up period for all patients was between 18 and 72 months. There was no perioperative mor tality. No infection or rejection of prostheses was recorded. Seroma w as present in four patients. Computed tomography was performed for eva luation purposes on 10 randomly selected patients (mean postoperative delay 1-4 years) and showed the ePTFE encapsulated by newly formed tis sue. One of the patients suffered from mechanical intestinal obstructi on 40 days after implant and suffered a recurrence a year later. Three recurrences at the patch-recipient tissue interface where the ePTFE h ad been secured with a single row of polypropylene stitches were recor ded after 8, 12, and 28 months. At 40 days good integration of the bio material was observed in the newly formed tissue. On both sides of the implant an accumulation of four to six strata of cells was appreciabl e. Some of them were labeled with KP-1. Cell infiltration of the prost hesis was restricted to the most exterior third of the patch. There wa s no colonization at the patch-recipient tissue interface. At 12 and 2 8 months the cell barrier had almost disappeared. KP-1-labeled macroph ages were scarce. Scanning electron microscopy revealed a well defined peritoneum. It may be concluded that: (1) a double suture row is reco mmended to secure the prosthesis; (2) ePTFE provides an adequate subst rate for the formation of scar tissue; and (3) the macrophage response induced by the ePTFE decreases with time.