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Using a newly developed Doppler probe, we have found that a standard suture anastomosis in a rat femoral artery is accompanied by significant (30-60%) cross-sectional area stenosis, which dissipates to baseline levels within 24 hours. We hypothesized that spasm, deposition of coagulation products, or the suture technique itself was responsible. Topical vasodilators (papaverine, sodium nitroprusside, lidocaine) and intravenous thromboxane A2 synthetase inhibitor and receptor blocking agent (Ridogrel, 4 mg/ml), anticoagulants heparin and SC4992 (an experimental platelet inhibitor/arginine-glycine-aspartic acid analogue), were administered. No drug had any significant effect on preventing postoperative stenosis. Varied suture bites affected stenosis measurements. Scanning electron microscopy and light microscopy displayed "bunching" of vessel wall in the suture ties. This was confirmed with methyl methacrylate corrosion casts and microangiography. "Sham" anastomoses also produced stenosis, which was relieved when sutures were removed. We conclude that suture anastomosis of small vessels is accompanied by significant cross-sectional stenosis caused by the physical action of tensioned sutures. This effect dissipates over a 24-hour postoperative period. The mechanism behind these changes and the clinical importance of this effect are still under investigation.

Wound contraction is an important component of healing but, in the extreme, may lead to excessive scar formation and pathological wound contracture. Fetal rabbit wounds heal without contraction or scarring, whereas excisional fetal sheep wounds have been shown to contract, but no scarring or pathological wound contracture is noted. We used an in vitro model, the fibroblast-populated collagen lattice, to study the ability of fetal fibroblasts to coordinate contraction of a collagen matrix and the modulating effects of epidermal growth factor and transforming growth factor-beta 1 on this contraction. With increasing gestational age, fibroblasts increased the degree of collagen lattice contraction. Epidermal growth factor inhibited contraction by fetal fibroblasts, whereas transforming growth factor-beta 1 stimulated it. These findings suggest that while intrinsic differences between fetal and adult fibroblasts exist, polypeptide growth factors may operate at the site of tissue repair to alter cell phenotype. Further work is underway to delineate the role of soluble protein factors responsible for the absence of scarring and contracture seen in the fetal wound.

Introduction: Treacher Collins syndrome is an autosomal dominant mandibulofacial dysostosis with characteristic hard- and soft-tissue facial abnormalities. These include ocular malformations, ear malformations, and hypoplasia of the facial skeleton, especially of the malar bones and mandible. Traditionally, surgical correction of the facial abnormalities has focused on skeletal reconstruction to restore facial form and symmetry. In this report, we describe the use of customized parascapular free flaps, after standard reconstructive surgeries, for the correction of defects of facial contour in Treacher Collins patients. In most cases, bony reconstruction of the zygoma or periorbita is not required. Methods: From June 1995 to December 2003, 8 patients with Treacher Collins syndrome underwent microsurgical correction of facial contour using 16 free flaps. In all patients, staged parascapular free flaps were used for reconstruction. The microvascular technique involved a 2-team approach with simultaneous ipsilateral parascapular flap harvest and facial pocket dissection. The flaps were contoured, revascularized (14 superficial temporal vessels, 2 facial vessels), and inset. No vein grafts were used. The patients were followed for a minimum of 1 year, and postoperative evaluation included medical photography, visual assessment, and evaluation by the patient and family. Results: Seven patients had previous facial skeleton correction using craniofacial techniques. The age at operation ranged from 4-19 years. Sixteen parascapular free flaps were used in the 8 patients. Postoperative complications were limited to 1 hematoma. There were no partial or total flap losses. All of the patients had improved facial contour and symmetry. Overlying skin tone and color similarly improved. Conclusion: After traditional skeletal reconstruction for the complex craniofacial defects of Treacher Collins syndrome, deficiencies in facial contour and symmetry usually persist. Customized soft-tissue free flaps can be employed to differentially resurface these defects and achieve optimal esthetic results in these challenging patients.

Evolving microsurgical technique has allowed for the anastomosis of smaller diameter vessels. Standard suture anastomoses cause a measure of stenosis and intimal damage during application and therefore cannot be dependably used in the anastomosis of very small vessels. We developed and tested a fibrin glue-based anastomosis applied over a meltable stent made of mono- di- and tri-glycerides. In vivo rodent studies using the 0.35 mm diameter inferior epigastric artery have shown immediate and short-term patency rates better than those associated with suture technique. The stent technique is significantly faster and easier than the suture technique. The glyceride stent method suffers from decreased late patency due to aneurysm formation. In addition, we developed a glyceride-coated polyethylene glycol-based stent for use in lasered anastomoses. Work on both projects is ongoing.

Tissue expansion alters the function of skin cells. We studied the effects of expansion on the contractile function of dermal fibroblasts using an in vitro model, the fibroblast-populated collagen lattice (FPCL). Spherical expanders were placed dorsally in 30 Sprague-Dawley rats; one-half were serially inflated. One, 2, and 4 weeks later, 5 rats from each group were killed. Fibroblasts were cultured from dermis overlying the expanders and mixed with collagen, medium, and serum in petri dishes to form FPCL. Fibroblasts from 5 rats that had not undergone surgery were cultured to make control FPCL. Contraction was assessed by measuring the areas of the FPCL. At 48 hours, FPCL containing expanded fibroblasts had contracted significantly less than those containing unexpanded or control fibroblasts. Four weeks of expansion resulted in less contraction than 1 or 2 weeks. Tissue expansion inhibits the in vitro contractile function of dermal fibroblasts in the rat in a time-related fashion.