Faculty Bibliography

It is hypothesized that unlike solid organ transplants immunosuppression of peripheral nerve allografts is needed only for the finite time period required for regeneration of proximal host nerve axons through the allograft and subsequent re-establishment of host end-organ connections. The aim of this study was to explore the consequences of temporary and continuous systemic Cyclosporine A (CsA) immunosuppression upon peripheral nerve allograft survival. Buffalo rats received Lewis nerve allografts under CsA immunosuppression (5 mg/kg/day) either continuously for 20 weeks, or for only 10 weeks followed by abrupt withdrawal. At 20 weeks, the nerve segments from both groups were regrafted into naive Buffalo or Lewis recipients without further immunosuppression. These grafts were compared with isografts, unimmunosuppressed allografts and allografts immunosuppressed for 10 weeks in situ. By eight weeks following regrafting, the secondary Lewis recipients had rejected the temporarily immunosuppressed allografts and accepted the continuously immunosuppressed allograft, while the secondary Buffalo recipients accepted both the temporarily and continuously immunosuppressed allografts as assessed by histology and morphometry. Functional recovery was earlier in secondary recipient strain animals that received temporarily immunosuppressed allografts in comparison to those that received continuously immunosuppressed allografts. Analysis of secondary recipients of temporarily immunosuppressed allografts demonstrated greater in vitro MLR and LDA reactivity than did those receiving continuously immunosuppressed allografts. These findings support the hypothesis that donor alloantigens are lost or replaced by the recipient after immunosuppression withdrawal. Moreover, the change to recipient antigenicity in the nerve allograft is retarded and incomplete under continuous CsA immunosuppression, resulting in acceptance by both secondary donor and recipient strains upon regraftment

We describe a distally based flap of the medial head of the gastrocnemius, vascularized through a distal pedicle given off by the posterior tibial artery. A literature review showed that this flap and the distal pedicle had not been described previously as such, although several techniques have been used to cover a substance loss of the distal third of the leg using the medial gastrocnemius. The distal artery has a variable caliber, and it is not always possible to raise the flap. One patient has been operated on by this technique, and an anatomic study was performed showing that 9 of 30 legs had a distal pedicle larger than 1 mm, 14 had a pedicle smaller than 1 mm, and 7 had a microscopic pedicle too small to raise a flap

Degos' disease (malignant atrophic papulosis) is a rare, progressive, small- and medium-size arterial occluding disease, leading to tissue infarction and initially involving the skin. We report a case with bowel involvement followed by enterocutaneous fistulae. Diagnostic laparoscopy with jejunal biopsy was followed by jejunal perforations, peritonitis, and fistulae leading to death after a 4-month course in the intensive care unit. The usual treatment of enterocutaneous fistula by somatostatin and parenteral nutrition was ineffective in this case. The course of the disease in our patient was not usual, as can be seen in a literature review underlining the specific features of Degos' disease. Laparoscopy and bowel biopsy should be avoided in this context. Degos' disease should be considered in the differential diagnosis of a primary ulceration of the small intestine

A model to evaluate the efficacy of therapies aimed at reducing the failure rate of microvascular free flaps was developed in the rat, inspired by earlier work on the rabbit ear by Ozbek et al. (Ann Plast Surg 32:474-477, 1994). It consisted in raising an epigastric groin flap on the femoral pedicle, while cutting the femoral artery, twisting it around the femoral vein, and resuturing it. Immediate patency was always seen, but 19 of 20 such anastomoses presented with thrombosis after 24 hours (15 venous and 4 mixed thromboses). Ten similar anastomoses performed without twisting did not result in thrombosis (P = 0.000000366). This model appears to be adequate for simulating free flap failure

A microvascular free flap failure model consisting of raising an epigastric groin flap on the femoral pedicle, while cutting the femoral artery, twisting it around the femoral vein and resuturing it, has been previously described. As it was being evaluated, normovolemic hemodilution as a means to prevent thrombosis was simultaneously assessed using an additional experimental group. Twenty percent of the blood mass of each rat was taken and replaced with a hydroxyethyl starch solution immediately before surgery. Only 14 out of 20 anastomoses presented with thrombosis (13 venous and one mixed), as opposed to 19 out of 20 animals operated on without hemodilution (P< 0.05). Normovolemic hemodilution appears to be an effective method of reducing microvascular free flap failure