Human acellular dermal matrix for ventral hernia repair reduces morbidity in transplant patients.

PURPOSE: Organ transplantation is widely accepted as the treatment of choice for native organ failure. Due to required immunosuppression, however, organ recipients are prone to wound infections, incisional hernias, and fascial dehiscence. These complications are especially dangerous in this patient population, as they can compromise the survival of the transplanted organ. Various methods have been employed to repair ventral and incisional hernias in these patients. These include primary repair, synthetic mesh, biologic mesh, tensor fascia lata grafts (TFL), component separation, flaps from the thighs, or a combination of these. The goal of this study was to review the experience at our institution with ventral hernia repair in transplant patients and to compare outcomes of the various repair techniques. METHODS: Patients with liver, renal, or pancreas transplants requiring immunosuppression who underwent a ventral or incisional hernia repair at the University of Maryland from 2000-2005 were reviewed retrospectively. Factors examined include type and location of hernia, type of repair, post operative infection, hernia recurrence, reoperation, mesh removal, and length of follow up. Complication rates were compared using odds ratio and chi-square. RESULTS: A total of 104 patients met the criteria with a mean length of follow up of 26 months. Of these, 34 patients had repair with human acellular dermal matrix (HADM), 26 had synthetic mesh, 25 had primary repair, and 9 had TFL. Rates of wound infection in these groups were 15, 65, 8, and 11% respectively (χ (2) = 28, P < 0.001). Rates of recurrence were 24, 77, 36, and 11% respectively (χ (2) = 22, P < 0.001). The rate of mesh removal with HADM and synthetic mesh were 12 and 69%, respectively (χ (2) = 14, P < 0.001). When comparing HADM and synthetic mesh, the odds ratio for wound infection is 11 (95% CI 3.2-38) and for mesh removal is 8.7 (95% CI 2.6-28). CONCLUSION: When repairing ventral or incisional hernias in immunosuppressed transplant patients, HADM provides significantly reduced morbidity from reduced rates of infection, recurrence, and need for operative removal of mesh.

Self-evaluation effects of interpersonal versus intergroup social comparison.

Two studies tested the prediction that the outcome of social comparison will differ depending on whether interpersonal or intergroup comparison processes have been engaged. Results of an experiment in which college student participants were assigned to membership in a minority or majority social category confirmed the predicted three-way interaction effect of in-group salience, target group membership, and upward-downward comparison on self-assessments of academic ability. Majority group members exhibited contrast effects in their self-ratings following exposure to a videotape of an in-group member displaying either very high or very low academic competence. Self-evaluations of minority group members revealed assimilation effects in response to in-group comparisons and contrast effects in response to out-group comparisons. In a second, follow-up experiment, this in-group assimilation effect was found to be dependent on intergroup contrast.

Effects of group identity on resource use in a simulated commons dilemma.

In a review of research on in-group categorization and group identity, Brewer (1979) proposed that cooperative solutions to social dilemmas, such as Hardin 's (1968) "tragedy of the commons ", may be achieved by exploiting the positive consequences arising from a common social-group identity. Three laboratory experiments were conducted to assess the effects of making salient either a superordinate (collective) or subordinate (differentiating) group identity in heterogeneous groups. In the first two experiments, naturally occurring social categories were used as a basis for group differentiation. In the third, the level of social-group identity was manipulated by varying the common fate of the group members. It was predicted that individual restraint would be most likely when a superordinate group identity was made salient and under conditions in which feedback indicated that the common resource was being depleted. Results from all three experiments provide support for this general hypothesis, indicating that cooperative responding is enhanced even when the basis for superordinate group identity is minimal.