Publications by authors named "Andrew Pappa"

Background: Oral cavity reconstruction is very challenging anatomical subsite to reconstruct. Large defects often require free tissue reconstruction to provide the best chance of form and function. Additionally, free tissue reconstruction aids to prevent fistula formation.

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Background: Balloon sinuplasty is increasingly used in the outpatient clinic for treatment of chronic rhinosinusitis, but radiologic analysis of its effects on sinonasal anatomy is largely uncharacterized in the known literature.

Objective: The purpose of this study is to examine the anatomic effects of balloon sinuplasty in a cadaveric model.

Methods: Five fresh cadaver heads underwent sequential endoscopic balloon dilation of maxillary ostia, frontal recess outflow tracts, and sphenoid ostia bilaterally by fellowship-trained rhinologists.

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Background: Primary ciliary dyskinesia (PCD) is a genetically diverse disease which causes impaired mucociliary clearance, and results in pulmonary, otologic, and rhinologic disease in affected patients. Genetic mutations in multiple genes impair the ability of patients to clear mucous from the lungs, middle ear, and sinonasal cavity and lead to chronic pulmonary and sinonasal symptoms.

Methods: We identified 17 PCD patients who had available CT scans.

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The cochlear summating potential (SP) to a tone is a baseline shift that persists for the duration of the burst. It is often considered the most enigmatic of cochlear potentials because its magnitude and polarity vary across frequency and level and its origins are uncertain. In this study, we used pharmacology to isolate sources of the SP originating from the gerbil cochlea.

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Objective: Active surgical drains minimize fluid accumulation in the postoperative period. The Jackson-Pratt (JP) system consists of a silicone drain connected by flexible tubing to a bulb. When air in the bulb is evacuated, negative pressure is applied at the surgical site to aspirate fluid.

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Objective: Understanding the independent predictors of poor outcomes in free flap surgery is essential for patient selection. We aim to determine the independent predictors of major complications, flap survival, and extended hospital stays.

Study Design: Retrospective cohort study.

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Background: Mechanical properties of tissue-engineered cartilage and a variety of endogenous cartilage were measured. The main goal was to evaluate if the tissue-engineered cartilage have similar mechanical characteristics to be replaced with rib cartilage in microtia reconstruction. Such study lays the foundation for future human clinical trials for microtia reconstruction.

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Hyperparathyroidism is a common disorder affecting more than hundreds of thousands of people annually. While most commonly secondary to an adenoma, it may also arise from four-gland hyperplasia or malignancy. In the case of primary hyperparathyroidism, the number of glands involved may be unknown prior to surgery.

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The inferior colliculus (IC) is the common target of separate pathways that transmit different types of auditory information. Beyond tonotopy, little is known about the organization of response properties within the 3-dimensional layout of the auditory midbrain in most species. Through study of interaural time difference (ITD) processing, the functional properties of neurons can be readily characterized and related to specific pathways.

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Hypothesis: The compound action potential (CAP) is a purely neural component of the cochlea's response to sound, and may provide information regarding the existing neural substrate in cochlear implant (CI) subjects that can help account for variance in speech perception outcomes.

Background: Measurement of the "total response" (TR), or sum of the magnitudes of spectral components in the ongoing responses to tone bursts across frequencies, has been shown to account for 40 to 50% of variance in speech perception outcomes. The ongoing response is composed of both hair cell and neural components.

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The need for tissue-engineered bone to treat complex craniofacial bone defects secondary to congenital anomalies, trauma, and cancer extirpation is sizeable. Traditional strategies for treatment have focused on autologous bone in younger patients and bone substitutes in older patients. However, the capacity for merging new technologies, including the creation of nanofiber and microfiber scaffolds with advances in natal sources of stem cells, is crucial to improving our treatment options.

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A programmable bioreactor using a voice-coil actuator was developed to enable research on the effects of periodic vibratory stimulus on human and porcine mesenchymal stem cells (MSCs). We hypothesized that low frequency vibrations would result in a cartilage phenotype and higher frequency vibrations would result in a bone phenotype. The mechanical stimulation protocol is adjusted from a computer external to the incubator via a USB cable.

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Objective: Microtia is treated with rib cartilage sculpting and staged procedures; though aesthetically pleasing, these constructs lack native ear flexibility. Tissue-engineered (TE) elastic cartilage may bridge this gap; however, TE cartilage implants lead to hypertrophic changes with calcification and loss of flexibility. Retaining flexibility in TE cartilage must focus on increased elastin, maintained collagen II, decreased collagen X, with prevention of calcification.

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Background: A key to clinical microtia reconstruction is construct flexibility. The most significant current limitation to engineered elastic cartilage is maintaining an elastic phenotype, which is principally dependent on elastin production (although other parameters, including maintenance of a ratio above 1 for collagens II to I, minimizing collagen X content, and presence of adequate matrix fibrillin for elastin binding, all play supporting roles). Connective tissue growth factor (CTGF), a compound secreted by chondrocytes, has been shown to promote an elastic phenotype in mature rabbit chondrocytes; however, CTGF effect on undifferentiated mesenchymal stem cells (MSCs) has not been characterized.

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Objective: Nanofiber-supported, in vitro-generated cartilage may represent an optimal starting material for the development of a cartilage implant for use in microtia reconstruction. To do so, the authors aim to first characterize the molecular composition of endogenous auricular cartilage and determine if human umbilical cord mesenchymal stem cells (hUCMSCs) can be differentiated into cartilage in vitro.

Study Design: Prospective, controlled.

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