Faculty Bibliography

BACKGROUND: The study of human autologous fat grafting has been primarily anecdotal. In this study, the authors aim to develop a murine model that recapitulates human fat grafting to study the fate of injected fat and the cell populations contained within. METHODS: The authors' method of fat harvesting and refinement has been described previously. The authors injected nude and tie2/lacZ mice with 2 ml of human lipoaspirate placed on the dorsal surface in a multipass, fan-like pattern. Fatty tissue was injected in small volumes of approximately 1/30 ml per withdrawal. The dorsal skin and associated fat was excised at various time points. Sections were stained with hematoxylin and eosin and cytochrome c oxidase IV. Transgenic tie2/lacZ samples were stained with X-galactosidase. At the 8-week time point, volumetric analysis was performed. RESULTS: Volumetric analysis at the 8-week time point showed 82 percent persistence of the original volume. Gross analysis showed it to be healthy, nonfibrotic, and vascularized. Hematoxylin and eosin analysis showed minimal inflammatory or capsular reaction, with viable adipocytes. Fat grafted areas were vascularized with multiple blood vessels. Cytochrome c oxidase IV human-specific stain and beta-galactosidase expression revealed these vessels to be of human origin. CONCLUSIONS: The authors have developed a murine model with which to study the fate of injected lipoaspirate. There is a high level of persistence of the grafted human fat, with minimal inflammatory reaction. The fat is viable and vascularized, demonstrating human-derived vessels in a mouse model. This model provides a platform for studying the populations of progenitor cells known to reside in lipoaspirate

We propose that high-fidelity animations enhanced with real-time 3d interactivity, that demonstrate various breast reconstruction procedures will assist in a patient's decision-making process. These computer based modules will in no way replace a consultation with the physician; instead they will be added to the armamentarium of patient education

BACKGROUND: Gustilo IIIB fractures involve high-energy tibial fractures for which there is inadequate soft tissue coverage. In addition to orthopedic fixation, these injuries require soft tissue reconstruction, often in the form of a microvascular free flap. Although the majority of orthopedic literature favorably compares intramedullary rod fixation to external fixation in open tibial fractures, these studies have not focused on the role of either method of fixation in relation to the soft tissue reconstruction. METHODS: Because we had noted numerous complications after providing free-flap coverage over intramedullary rodded fractures, we sought to investigate whether there were differences in outcomes between free flap-covered lower-extremity fractures which were fixated by external fixation versus intramedullary rods. A retrospective chart review was performed on all patients in our institution who had lower-extremity free flaps for coverage of Gustilo IIIB fractures from 1995-2005 in relation to the type of bony fixation. RESULTS: Of the 38 patients studied, 18 underwent external fixation of the tibial fracture, and 20 had intramedullary rodding. Overall flap survival was 95%, with 1 failure in each group. However, the intramedullary rod group had higher incidences of wound infection, osteomyelitis, and bony nonunion (25%, 25%, and 40%, respectively) than the external fixation group (6%, 11%, 17%, respectively). CONCLUSIONS: For Gustilo IIIB fractures that require free-flap coverage, the added bony and soft tissue manipulation required for intramedullary rodding may disrupt the surrounding blood supply and lead to higher rates of complications that threaten the overall success of the reconstruction. Plastic and orthopedic surgeons should discuss the optimal method of bony fixation for complex tibial fractures when a free flap will likely be needed for soft tissue coverage. This integrated team approach may help minimize complications

Successful nonextremity replantations, particularly of the facial anatomy and testicles, are rare procedures, and only a handful of cases have been reported. This article reviews the current literature in nonextremity replantations and representative cases performed at the authors' institution. Certain underlying themes and problems are consistently encountered in the surgical management of these cases. These are identified and reviewed. Although the replantation of these body parts remains technically challenging, all efforts should be made, when indicated, to repair these injuries microsurgically, because it currently offers the best reconstructive solution for these patients

BACKGROUND: Gene therapy for cancer holds enormous therapeutic promise, but its clinical application has been limited by the inability to achieve targeted, high-level transgene expression with limited systemic toxicity. The authors have developed a novel method for delivering genes to microvascular free flaps (commonly used during reconstructive surgery) to avoid these problems. METHODS: During the finite period in which a free flap is separated from the host (ex vivo), it can be perfused with extremely high titers of genetic material through the afferent artery, resulting in efficient transduction of the tissue. Before reanastomosis, unincorporated genetic material is flushed from the flap, minimizing systemic toxicity. RESULTS: In a rodent model using an adenoviral vector containing the lacZ reporter gene, high regional expression of beta-galactosidase was achieved in all the different cells in a microvascular free flap. Moreover, no beta-galactosidase staining was observed outside of the transduced flap, and viral sequence was undetectable by polymerase chain reaction analysis in other tissues. Further analysis confirmed that high-level transgene expression was precisely localized to the explanted tissue, with no collateral transduction. CONCLUSIONS: Targeting gene delivery with minimal systemic toxicity is essential for successful gene therapy. This form of 'biological brachytherapy' provides a new opportunity to deliver targeted therapeutic transgenes to patients undergoing reconstructive surgery and allows microvascular free flaps to perform therapeutic and reconstructive functions

Intraoperative evaluation of skin flap viability has primarily been dependent on clinical judgment. The purpose of this study was to determine whether an orthogonal polarization spectral imaging device could be used to accurately predict viability of random-pattern skin flaps. Orthogonal polarization spectral imaging is a newly developed technique that visualizes the microcirculation using reflected light without the use of fluorescent dyes and allows for noninvasive real-time observation of functional microvascular networks. In Sprague-Dawley rats (n = 24), three types of random skin flaps were designed with unknown zones of viability (n = 8 per group). After flap elevation, the skin flaps were evaluated by both clinical examination and orthogonal polarization spectral imaging. Areas of the flap determined to be nonviable by clinical examination were measured and marked. Orthogonal polarization spectral imaging was subsequently performed, and areas of the skin flap with stasis (i.e., cessation of red blood cell movement) in the dermal microcirculation on orthogonal polarization spectral imaging were measured and marked. The skin flaps were then secured in place. Flaps were evaluated on a daily basis for clinical signs of ischemia and necrosis. On postoperative day 7, the total amount of random skin flap necrosis was measured and recorded. Clinical examination of the random skin flaps significantly underestimated the actual amount of eventual flap necrosis, and as result was a very poor predictor of flap necrosis. By contrast, assessment of microcirculatory stasis using the orthogonal polarization spectral imaging device correlated well with the subsequent development of necrosis in all groups. In the three groups, the average amount of flap necrosis predicted by clinical examination deviated from actual necrosis by approximately 2 to 4 cm. However, the amount that orthogonal polarization spectral imaging differed from actual necrosis was 0.1 to 0.3 cm. Therefore, orthogonal polarization spectral imaging was an excellent predictor of eventual flap necrosis and much more accurate than clinical observation (p < 0.001). Intraoperative evaluation of axial and random pattern flap viability has traditionally been based on clinical examination as no other reliable, convenient test currently exists. The authors demonstrated that an orthogonal polarization spectral imaging device accurately predicts zones of necrosis in random pattern flaps by directly visualizing cessation of microcirculatory flow. Intraoperative stasis in the dermal microcirculation correlated precisely with subsequent flap necrosis. Orthogonal polarization spectral imaging was significantly more accurate than clinical examination, which consistently underestimated flap necrosis. The orthogonal polarization spectral imaging technique may have value in the intraoperative assessment of skin flap perfusion such as that required after skin-sparing mastectomy