Faculty Bibliography

PURPOSE/OBJECTIVE:This cadaver dissection studied the relationship of the buccal branch of the facial nerve to the parotid duct and its relevance to surgical procedures in this area. MATERIALS AND METHODS/METHODS:Ten cadaveric heads (twenty sides) were dissected. The superficial tissues were removed, and the buccal branch of the facial nerve and the parotid duct were identified. The vertical and horizontal relationships were recorded and analyzed. RESULTS:Eighty-five percent of the cadavers had a single buccal branch of the facial nerve, whereas 15% had two branches. In 75% of cases, the nerve was inferior to the duct as it emerged from the parotid gland, whereas in 25% of cases the nerve crossed the duct, usually from superior to inferior. CONCLUSION/CONCLUSIONS:The buccal branch of the facial nerve has a close relationship with the parotid gland for over 2.5 cm after it emerges from the parotid gland; it normally lies inferior to the duct. This relationship is of importance in performing parotid gland surgery, parotid duct surgery, and some facial cosmetic surgery.

Growth of normal melanocytes, nevus cells and primary melanoma cells is enhanced by insulin/insulin-like growth factor-I (IGF-I) in vitro. It has been shown that a melanoma cell line possesses the IGF-I receptor which plays a role in activation of the chemotactic response. Little is known about the in vivo expression of the IGF-I receptor and its role in melanocytic lesions. In an immunohistochemical study, we investigated the expression of IGF-I receptor in frozen sections of congenital pigmented nevi from 10 patients (ages 8 months to 4 yrs) using the monoclonal antibody alpha IR3, which specifically recognizes the extracellular alpha subunit of the IGF-I receptor. The proliferative activity of the nevus cells was examined by staining with Ki67 monoclonal antibody (reactive with all actively cycling cells). IGF-I receptor was found to be widely expressed by the cell surface of the nevus cells. Membrane staining was occasionally stronger in the superficial portion of the congenital pigmented nevi. In contrast, Ki67-positive cells were only sparsely scattered throughout the nevi with some tendency to localization to the superficial portion. This study indicates that in vivo the IGF-I receptor is widely expressed by congenital pigmented nevus cells. As opposed to keratinocytes, in which IGF-I receptor expression defines the proliferation pool of the normal and disordered epidermis, the IGF-I receptor is expressed by all nevus cells, irrespective of their proliferative status. Further studies are needed to assess whether the IGF-I receptor expression can serve as a marker for increased risk for development of malignancy in various types of benign melanocytic lesions.

The most common recipient site for free-flap breast reconstruction is the subscapular system. Because of a number of problems we encountered using this recipient site, we became interested in revisiting the internal mammary vessels. This paper reports the use of the internal mammary artery and vein as a recipient site in 110 consecutive cases of breast reconstruction in 87 patients. We also report the technical details of recipient-vessel dissection and vessel size in our series. Complications encountered in the series are discussed, and the advantages of using the internal mammary vessels are enumerated. Our experience of a 99 percent successful flap transfer rate supports the reliability of these recipient vessels in breast reconstructions.

With the use of microsurgery, we have developed a method of measuring hemodynamic parameters in a rat not possible with previous technology. Three groups of rats were studied: a chemically induced pulmonary hypertensive group (PH); a chemically induced pulmonary hypertensive group treated with single lung transplantation (LT); and an untreated, control group (C). Cardiac output, heart rate, and pulmonary vascular resistance were then calculated in each group from data obtained by 1 mm high fidelity micromanometers and an ultrasonic flow probe. The results show that the data collected from the rodent model are reproducible within each group, and data quality is comparable to large animal models. With this new method, data can be collected in a small animal model at a fraction of the time and cost of large animal studies. Additionally, the complications of graft rejection in large animal studies are eliminated in an isogenic rodent model.

To make a quantitative assessment of the relationship between size of vascular carrier and surviving area in a prefabricated flap, vascular carriers composed of the superficial epigastric arteriovenous bundles and a surrounding fascial patch with varying sizes were transferred under a 7- x 7-cm bipedicled abdominal skin flap in a rat model. Seven days later, the abdominal flaps were raised as composite island flaps connected only by the superficial epigastric vascular pedicle, transferred, and then sutured back into place. Immediately after replacement, the degree of revascularization was assessed using quantitative skin fluorometry, after intravenous injection of sodium fluorescein. At 7 days after elevation as an island flap, the area of skin flap surviving was recorded and plotted on a map depicting the original flap surface. High levels of fluorescence appeared on the flap surface where the carrier was tacked underneath. The prefabricated island flaps survived with a circular shape up to approximately 4 times the radius of the vascular carrier. When the distance was converted into area, theoretically, an area 13 times the area of the vascular carrier survived, regardless of its size in this experimental model. Histologic examination revealed connections of fine capillaries between the carrier and flap.

A new experimental model of a vascular carrier to prefabricate a "secondary" island flap, the popliteal musculovascular pedicle, was developed in the rat. Using quantitative skin-surface fluorometry 30 minutes after sodium fluorescein injection and a flap survival area in the prefabricated 8 x 2.5-cm abdominal composite island flap, we compared the revascularization ability of our muscular carrier to nonrevascularized controls: the skeletonized arteriovenous pedicle and the fasciovascular pedicle. The free composite graft with no vascular carrier exhibited near-total necrosis. The skeletonized vascular pedicle demonstrated 15.2% +/- 7.8% perfusion of normal skin on dye fluorescence index measurements and 50% flap survival. The fasciovascular pedicle exhibited better revascularization, with a dye fluorescence index of 36.2 +/- 15.5 (p < 0.01) and 90% +/- 10% flap survival (p < 0.001). India ink injection study and histological examination of our model provided visual evidence of revascularization from the musculovascular pedicle, along with preservation of the carrier's muscular architecture. The musculovascular pedicle is a reliable carrier for making new, vascularized composite flaps.