Faculty Bibliography

Blood vessel growth is regulated by angiogenic and angiostatic CXC chemokines, and radiation is a vasculogenic stimulus. We investigated the effect of radiation on endothelial cell chemokine signaling, receptor expression, and migration and apoptosis. Human umbilical vein endothelial cells were exposed to a single fraction of 0, 5, or 20Gy of ionizing radiation (IR). All vasculogenic chemokines (CXCL1-3/5-8) increased 3-13-fold after 5 or 20Gy IR. 20Gy induced a marked increase (1.6-4-fold) in angiostatic CXC chemokines. CXCR4 expression increased 3.5 and 7-fold at 48h after 5 and 20Gy, respectively. Bone marrow progenitor cell chemotaxis was augmented by conditioned media from cells treated with 5Gy IR. Whereas 5Gy markedly decreased intrinsic cell apoptosis (0Gy=16%+/-3.6 vs. 5Gy=4.5%+/-0.3), 20Gy increased it (21.4%+/-1.2); a reflection of pro-survival angiogenic chemokine expression. Radiation induces a dose-dependent increase in pro-angiogenic CXC chemokines and CXCR4. In contrast, angiostatic chemokines and apoptosis were induced at higher (20Gy) radiation doses. Cell migration improved significantly following 5Gy, but not 20Gy IR. Collectively, these data suggest that lower doses of IR induce an angiogenic cascade while higher doses produce an angiostatic profile

Pathologic resections involving the maxilla/hemimaxilla offer a unique reconstructive challenge to the maxillofacial reconstructive surgeon. Traditionally, reconstruction and replacement of lost tissues have been achieved with a variety of methods including obturators, local/regional flaps, and microvascular free tissue transfer. All these techniques have distinct disadvantages. We present a novel approach to palatomaxillary reconstruction using a combination of free tissue transfer and zygomaticus implants. To our knowledge, this specific technique has not been previously reported.

The Allen test is used to diagnose the relative contribution of the ulnar and radial arteries to each hand. We modified this test to investigate the relative vascular contributions to distal perfusion of the lower extremity. With the patient supine, a handheld Doppler is used to locate the first dorsal metatarsal artery. The posterior tibial artery (PT) and dorsalis pedis artery (DP) pulses are compressed. A persistent signal indicates collateral flow through the peroneal artery (PA). Sequential decompression is then used to evaluate the relative contribution of the PT and DP to distal circulation. We report a case in which angiography failed to predict reliance on the PT. In this case, performance of the lower-extremity Allen test (LEAT) led to an alternative recipient vessel choice. The LEAT is simple to perform and provides a valuable adjunct to angiographic data

OBJECTIVE: Determine long-term loss of mandible height with use of stress-shielding reconstruction plates for free fibula flap mandible reconstruction. DESIGN: Retrospective single-blinded medical record review. SUBJECTS: Seventy patients who had fibula free flap mandible reconstructions performed for 10 years. Patients who underwent radiotherapy were excluded. METHODS: Review of 70 fibula free flap mandible reconstructions performed for the last 10 years in a city hospital revealed 7 patients (10%) who had resections for benign odontogenic diseases. All had a three-dimensional cast model made, on which the reconstruction plate was bent to the desired shape preoperatively. Free fibula height on panoramic x-ray images taken preoperatively and at 2 and 12 months postoperatively. RESULTS: Seven (10%) patients met criteria for the study. Bone height was maintained at 2 months postoperatively, but at 12 months, there was a statistically significant loss of fibular bone height averaging 20% in the anterior, body, and ramus areas (P < 0.05). Despite this, all patients were considered eligible for dental rehabilitation, and 4 of 7 patients have had osseointegrated implants placed. CONCLUSIONS: As opposed to miniplates, increased resorption may have been due to the stress-shielding phenomenon unique to a reconstruction plates. However, this did not seem to affect the ability to place osseointegrated implants.

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

Free transverse rectus abdominis myocutaneous and deep inferior epigastric perforator flaps represent increasingly popular options for breast reconstruction. Although several retrospective, small-scale studies comparing these flap, have been published, most have failed to find a significant difference in flap complication rates or donor-site morbidity. We systematically reviewed the Current literature, and Subsequently pooled and analyze(] data from included studies. Included studies reported flap complications and/or donor site morbidities for both flap types. Eight studies met the inclusionary, criteria. For flap complications, there was a statistically significant difference between deep interior epigastric perforator and free transverse rectus abdominis myocutaneouS flaps in fat necrosis rates (25.5 +/- 0.49 vs. 11.3%, +/- 0.41%. P < 0.001) and total necrosis rates (4.15 +/- 0.08 vs. 1.59% +/- 0.08%, P = 0.044). Partial necrosis rates were not statistically Significant (3.54 +/- 0.07 vs. 1.60% +/- 0.07%, P = 0.057). For donor-site morbidity. there was no statistically significant difference in abdominal bulge (8.07 +/- 0.23 vs. 11.25% +/- 0.29%, P = 0.28). Multicenter. prospective studies are needed to further investigate differences between these flap options