Pathologic 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 relates 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 Patches. 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 the ePTFE was sutured to the recipient tissues with a double row of polypropylene stitches. For the first eight interventions the ePTFE was secured 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 light microscopy, scanning electron microscopy, and immunohistochemistry with human antimacrophage antibodies KP-1. The follow-up period for all patients was between 18 and 72 months. There was no perioperative mortality. No infection or rejection of prostheses was recorded. Seroma was present in four patients. Computed tomography was performed for evaluation purposes on 10 randomly selected patients (mean postoperative delay 1-4 years) and showed the ePTFE encapsulated by newly formed tissue. One of the patients suffered from mechanical intestinal obstruction 40 days after implant and suffered a recurrence a year later. Three recurrences at the patch-recipient tissue interface where the ePTFE had been secured with a single row of polypropylene stitches were recorded after 8, 12, and 28 months. At 40 days good integration of the biomaterial was observed in the newly formed tissue. On both sides of the implant an accumulation of four to six strata of cells was appreciable. Some of them were labeled with KP-1. Cell infiltration of the prosthesis was restricted to the most exterior third of the patch. There was no colonization at the patch-recipient tissue interface. At 12 and 28 months the cell barrier had almost disappeared. KP-1-labeled macrophages were scarce. Scanning electron microscopy revealed a well defined peritoneum. It may be concluded that: (1) a double suture row is recommended to secure the prosthesis; (2) ePTFE provides an adequate substrate for the formation of scar tissue; and (3) the macrophage response induced by the ePTFE decreases with time.