Faculty Bibliography

A significant body of literature supports a role for the dura mater underlying cranial sutures in the regulation of sutural fate. These studies have implicated regional differentiation of the dura mater based on association with fusing and patent rat cranial sutures. The purpose of these experiments was to isolate and characterize dural cells associated with fusing (posterior frontal) and patent (sagittal) rat cranial sutures. Six-day-old rats were killed, and the dura mater underlying the posterior frontal and sagittal sutures was harvested. Dural cells were briefly trypsinized and allowed to reach confluence. Two litters (10 animals per litter) were used for each set of experiments. Cells were harvested after the first and fifth passages for analysis of vimentin and desmoplakin expression (characteristic of human meningeal cells), cellular proliferation, density at confluence (a measure of cellular contact inhibition), and alkaline phosphatase production. In addition, bone nodule formation and collagen I production were analyzed in first passage cells. The results indicate that suture-derived dural cells can be established and that these cells coexpress vimentin and desmoplakin. In addition, it is demonstrated that first-passage sagittal suture-derived dural cells proliferate significantly faster and have decreased cellular contact inhibition than posterior frontal suture-derived cells (p < 0.01). Finally, it is shown that suture-derived dural cells have osteoblast-like properties, including alkaline phosphatase production, collagen I expression, and bone nodule formation in vitro. The possible mechanisms by which regional differentiation of suture-derived dural cells occur are discussed

OBJECTIVE: This objective of this study was to determine the effect of presurgical nasoalveolar molding on long-term nasal shape in complete unilateral clefts. DESIGN: The study was retrospective, and the subjects were chosen at random. Nasal casts of the subjects were scanned in three dimensions. Each nose was best fit to its mirror image, and a numerical asymmetry score was determined. SETTING: All patients were treated at the Institute of Reconstructive Plastic Surgery, NYU Medical Center, New York, New York. PATIENTS: The study subjects (n = 10) were selected from a group that had undergone presurgical nasal molding in conjunction with alveolar molding. The control subjects (n = 10) were selected from a group that had undergone presurgical alveolar molding alone. INTERVENTIONS: All subjects underwent presurgical orthopedic treatment until the age of approximately 4 months at which time the primary surgery was performed. MAIN OUTCOME MEASURE: The nasal shape following nasal molding should be more symmetrical than if molding had not been done. RESULTS: The mean asymmetry index for the nasoalveolar molding group was 0.74, and the control group was 1.21. This difference was statistically significant (p < .05). CONCLUSIONS: Presurgical nasoalveolar molding significantly increases the symmetry of the nose. The increase in symmetry is maintained long term into early childhood. The limitations of this study include (1) asymmetry alone is not an adequate shape result in most situations, (2) the children evaluated in this study were not fully grown, and (3) the control group was not age matched

Numerous studies have demonstrated the critical role of angiogenesis for successful osteogenesis during endochondral ossification and fracture repair. Vascular endothelial growth factor (VEGF), a potent endothelial cell-specific cytokine, has been shown to be mitogenic and chemotactic for endothelial cells in vitro and angiogenic in many in vivo models. Based on previous work that (1) VEGF is up-regulated during membranous fracture healing, (2) the fracture site contains a hypoxic gradient, (3) VEGF is up-regulated in a variety of cells in response to hypoxia, and (4) VEGF is expressed by isolated osteoblasts in vitro stimulated by other fracture cytokines, the hypothesis that hypoxia may regulate the expression of VEGF by osteoblasts was formulated. This hypothesis was tested in a series of in vitro studies in which VEGF mRNA and protein expression was assessed after exposure of osteoblast-like cells to hypoxic stimuli. In addition, the effects of a hypoxic microenvironment on osteoblast proliferation and differentiation in vitro was analyzed. These results demonstrate that hypoxia does, indeed, regulate expression of VEGF in osteoblast-like cells in a dose-dependent fashion. In addition, it is demonstrated that hypoxia results in decreased cellular proliferation, decreased expression of proliferating cell nuclear antigen, and increased alkaline phosphatase (a marker of osteoblast differentiation). Taken together, these data suggest that osteoblasts, through the expression of VEGF, may be in part responsible for angiogenesis and the resultant increased blood flow to fractured bone segments. In addition, these data provide evidence that osteoblasts have oxygen-sensing mechanisms and that decreased oxygen tension can regulate gene expression, cellular proliferation, and cellular differentiation

The size of the plastic surgery workforce has important effects on the financial environment of the specialty. Economic theory predicts that increasing the area supply of surgeons performing aesthetic surgery will result in lower fees for their services. This study tested that theory in the actual aesthetic surgery marketplace. The study examined the ratio of plastic surgeons to the general population of several states. It then traced the aesthetic surgery fees resulting from different densities of area plastic surgeons. This information was economically analyzed to project the fee effects of possible future changes in the number of practicing plastic surgeons. For the states of New York, California, and Texas, there is a proportional decrease in fees as the density of plastic surgeons increases. For example, New York has 34 percent more plastic surgeons proportionally than Texas, and its fees are 30 percent lower in real dollars. Economic analysis can project the fee effects of changing the supply of surgeons performing aesthetic surgery. The analysis reveals that a 30 percent national increase in the supply of plastic surgeons would lower fees by approximately 32 percent. Similarly, if the number of plastic surgeons increases by 50 percent, fees will decrease by approximately 53 percent. However, these fee effects can be mitigated by expanding the demand for aesthetic surgery. In conclusion, the size of the plastic surgery workforce has profound effects on the fees paid for aesthetic surgery, and the magnitude of these effects can be understood, predicted, and optimized using the tools of economics.

OBJECTIVES: Routine carpal tunnel electrodiagnosis frequently includes median (MPW) and ulnar (UPW) palm-wrist mixed nerve conduction latency determinations over 8 cm. Despite widespread use, normative palmar latency difference (PLD) and UPW values, and the relative utility of onset latency (OL) or peak latency (PL) measurements are controversial. The current study was conducted to determine normative values for these parameters. METHODS: MPW and UPW studies were performed unilaterally in 33 normal controls. The PLD-OL and PLD-PL were calculated. The mean, range, standard deviation, and upper limits of normal were determined. 74 hands (50 patients) with both clinical and electrophysiologic median neuropathy were also studied. RESULTS: The abnormal MPW and UPW cut-offs were both 1.8 ms (OL), and 2.3 ms (PL). The abnormal PLD cut-offs were 0.5 ms (OL and PL). Using either OL or PL, PLD parameters were similar within controls, and also within CTS patients. Using either OL or PL, UPW parameters were similar between controls and CTS patients. CONCLUSIONS: An abnormal PLD cut-off of 0.5 is recommended. This is slightly higher than some prior recommendations, however it should minimize the likelihood of false positive studies. Onset and peak latency measurements are likely to have similar clinical utility

BACKGROUND: Microvascular anastomosis remains one of the most technically sensitive aspects of free-tissue transfer reconstructions. Despite the availability of various mechanical anastomotic coupling systems for human clinical use during the last 8 years, reported clinical series remain rare. OBJECTIVE: To describe a clinical experience in applying a mechanical microvascular anastomotic coupling device (MACD) to end-to-side anastomotic configurations in head and neck free-flap reconstruction. METHODS: The MACD is a readily available high-density polyethylene ring-stainless steel pin system that has been found to be highly effective in clinical studies of end-to-end arterial and venous anastomosis and in laboratory studies of end-to-side anastomosis of rabbit arteries. RESULTS: Thirty-seven end-to-side venous anastomoses were attempted, of which 33 (89%) were completed. Of these, 9 patients had critical anastomoses (only 1 venous anastomosis per patient). In patients undergoing parallel venous anastomoses, 6 had both anastomoses performed using the MACD; in the remaining 12 patients, 1 of the anastomoses was performed using the MACD. A variety of donor flaps and clinical contexts were encountered. Flap survival in the MACD series was 100%. Four anastomoses were converted to conventional suture technique intraoperatively. CONCLUSIONS: The MACD is well suited to end-to-side venous anastomosis when carefully and selectively used by experienced microvascular surgeons. The most common clinical situation requiring this configuration and technique was the lack of ipsilateral recipient veins for end-to-end anastomosis or a ligated internal jugular vein stump that required this approach for device application. Previous radiation therapy does not appear to be a contraindication to its use