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

The potential widespread use of tissue-engineered matrices in soft-tissue reconstruction has been limited by the difficulty in fabricating and confirming a functional microcirculation. Acellular dermal matrix placed in a soft-tissue pocket acts as a scaffold to be incorporated by the host's fibrovascular tissue. A new method for noninvasive real-time observation of functional microvascular networks using orthogonal polarization spectral (OPS) imaging has recently been reported. Arterioles, venules, and capillaries can be directly visualized, and the movement of individual blood cells through them can be observed. The present study was performed to investigate the use of prefabricated acellular dermal matrix with an arteriovenous unit for the repair of abdominal muscle defects. OPS imaging was used to determine the presence of a functional microcirculation in the neovascularized matrix. In Sprague-Dawley rats, vascularized matrix was prefabricated by placing the superficial epigastric artery and vein on a 2-cm x 2-cm implant-type acellular dermal matrix in the thigh. Three weeks after implantation, the matrix-arteriovenous unit was elevated as an axial-type flap and a 2-cm x 2-cm full-thickness block of abdominal muscle immediately superior to the inguinal ligament was resected. Additional procedures were performed according to group: no repair (group 1, = 20); repair with nonvascularized acellular dermal matrix (group 2, = 20); repair with devascularized acellular dermal matrix (group 3, = 20); and repair with vascularized acellular dermal matrix (group 4, = 20). OPS imaging (field of view, 1 mm in diameter; scan depth range, 0.2 mm) was performed on both sides of each flap on a total of 10 random distal regions before and after pedicle transection in group 3 and with the pedicle preserved in group 4. Hernia rate and duration of survival were compared for 21 days. OPS imaging showed directional blood cell movement through the capillary network in all areas scanned in group 4. No microvascular perfusion was observed after pedicle transection in group 3. Hernia rates of 100, 80, 90, and 0 percent were seen in groups 1, 2, 3, and 4, respectively. Median survival times of 9, 11.5, 9, and 21 postoperative days were noted in groups 1, 2, 3, and 4, respectively. Histopathologic analysis with factor VIII revealed full-thickness infiltration of the matrix by endothelial cells, signifying newly formed blood vessels. Repair of abdominal muscle defects using vascularized acellular dermal matrix resulted in no hernia and survival of all animals for the duration of study. However, repairs using avascular or devascularized matrix resulted in significant rates of hernia and decreased survival. Acellular dermal matrix can be prefabricated into vascularized tissue using an arteriovenous unit and used successfully to repair abdominal muscle defects. OPS imaging allowed for high-contrast direct visualization of microcirculation in previously acellular tissue following prefabrication with an arteriovenous unit