Publications by authors named "Payatakes A"

Neurofibromas are benign peripheral nerve sheath tumors that typically develop within cutaneous nerve branches but can involve major nerves as well. They can be sporadic or associated with neurofibromatosis type 1. In this report, we describe the surgical treatment of a pediatric patient with neurofibromatosis type 1 presenting with a neurofibroma of a bifid median nerve.

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Symphalangism is a rare, congenital syndrome involving ankylosis of the interphalangeal joints. We present a rare case of fracture at the level of a fused proximal interphalangeal joint in a patient with proximal symphalangism of the hand. Nonoperative management with splinting resulted in osseous healing and restored baseline function.

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Background: Traditional dogma regarding management of rheumatoid arthritis (RA) patients with trigger digit symptoms holds that A1 pulley release should be avoided. Surgical release was thought to further destabilize the metacarpophalangeal joint. Biologic disease modifying anti-rheumatic drugs (DMARDs) have limited the development of hand deformities.

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Spontaneous pseudoaneurysms are uncommon vascular lesions in children. A seven-month-old boy presented for management of a painless, pulsatile mass of the volar forearm identified as a pseudoaneurysm of the radial artery on imaging, definitively treated with surgical excision. Histology was concerning for fibromuscular dysplasia, without additional lesions on whole-body imaging.

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Purpose: To compare the efficacy of opioid versus nonopioid analgesic regimens after elective, soft tissue hand surgery. We hypothesized that there would be no difference in patient-perceived pain relief between these 2 groups.

Methods: This prospective, randomized, double-blinded controlled trial included patients undergoing elective soft tissue hand procedures (carpal tunnel release, trigger finger release, first dorsal compartment release, or ganglion cyst excision).

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Upper extremity adventitial cystic disease is rare, but the characteristic findings of this lesion should be known to the hand surgeon and used to guide treatment. We present a case of a young adult male who developed a painless mass in his distal forearm. Diagnostic imaging workup revealed a cystic mass that extended within and encased the radial artery.

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Reconstruction of extensive traumatic bone and soft tissue deficits in the hand often presents a significant challenge. We present a case of a gunshot wound managed with a resourceful "vascularized spare parts" reconstruction in which a single compromised digit provided two separate vascularized tissue transfers. A rarely reported pedicled phalanx restored osseous stability, a digital fillet flap achieved soft tissue coverage, and the flexor tendons reanimated the hand.

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Distal radioulnar dislocations typically occur in association with fractures of the distal radius and/or ulna. Rare isolated dislocations or subluxations are more difficult to diagnose and are initially missed in up to 50 % of cases. We present two cases of missed isolated volar rotatory dislocation of the distal radioulnar joint.

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Grip lock injuries are uncommon, potentially devastating occurrences in male gymnasts performing high bar routines, and typically cause severe wrist sprains or forearm fractures. We retrospectively reviewed medical records of a 24-year-old former collegiate gymnast surgically treated for complete loss of index and long finger extension (pseudorupture) after a grip lock injury. Intraoperative evaluation 3 weeks after injury revealed profound intratendinous attenuation of index and long finger extensors with adhesions in the fourth compartment.

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Fluid-structure interactions strongly affect, in multiple ways, the structure and function of cellular biological media, such as tissues, biofilms, and cell-entrapping gels. Mathematical models and computer simulation are important tools in advancing our understanding of these interactions, interpreting experimental observations, and designing novel processes and biomaterials. In this paper, we present a comprehensive survey and highlight promising directions of future research on theoretical modeling of momentum transport in cellular biological media with focus on the formulation of governing equations and the calculation of material properties both theoretically and experimentally.

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Conventional bone grafts have some osteogenic potential, whereas vascularized bone grafts retain live, functional osteocytes and osteoblasts. High rates of scaphoid union have been achieved with conventional bone grafting in the absence of osteonecrosis or prior surgery. Vascularized bone grafting is valuable in the management of wrist disorders with compromised bone vascularity (eg, scaphoid nonunion with proximal pole necrosis, Preiser disease, Kienböck disease) or when previous grafting has failed.

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We present a case of a 34-year-old white female patient who, 13 years ago, sustained a pathological intracapsular femoral neck fracture on a pre-existing aneurysmal bone cyst. Three months later radiographic and magnetic resonance imaging evaluation revealed both femoral neck fracture and stage IV osteonecrosis of the femoral head according to Steinberg classification system. Management was accomplished with combined free vascularized fibular grafting and internal osteosynthesis with a 130 degrees blade plate.

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Elbow arthritis is a debilitating condition manifesting as a painful, stiff elbow. Surgical treatment is based on disease etiology, severity of degeneration, and patient age. Rheumatoid elbows with mild to moderate disease benefit from arthroscopic debridement and synovectomy, whereas capsular release and ulnohumeral arthroplasty can relieve painful elbows with early posttraumatic arthritis and osteoarthritis.

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A laboratory prototype of a novel experimental apparatus for the analysis of spherical and axisymmetric nonspherical particles in liquid suspensions has been developed. This apparatus determines shape, volume, and refractive index, and this is the main difference of this apparatus from commercially available particle analyzers. Characterization is based on the scattering of a monochromatic laser beam by particles [which can be inorganic, organic, or biological (such as red blood cells and bacteria)] and on the strong relation between the light-scattering pattern and the morphology and the volume, shape, and refractive index of the particles.

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Visualization experiments of rate-controlled immiscible displacement of oil by water are performed on a model porous medium of controlled fractional wettability, fabricated by mixing water-wet glass microspheres with strongly oil-wet polytetrafluoroethylene microspheres and packing them between two transparent glass plates. The growth pattern is video recorded and the transient response of the pressure drop across the pore network is measured for various fractions of oil-wet particles. The space-averaged capillary pressure coincides to the pressure drop measured across the porous medium.

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Background: Spine deformity can be idiopathic (more than 80% of cases), neuromuscular, congenital or neurofibromatosis-related. However, there are many disorders that may also be involved. We present our experience treating patients with scoliosis or other spine deformities related to rare clinical entities.

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An integrated methodology is developed for the theoretical analysis of solute transport and reaction in cellular biological media, such as tissues, microbial flocs, and biofilms. First, the method of local spatial averaging with a weight function is used to establish the equation which describes solute conservation at the cellular biological medium scale, starting with a continuum-based formulation of solute transport at finer spatial scales. Second, an effective-medium model is developed for the self-consistent calculation of the local diffusion coefficient in the cellular biological medium, including the effects of the structural heterogeneity of the extra-cellular space and the reversible adsorption to extra-cellular polymers.

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Purpose: First, to determine the percentage of members of the American Society for Surgery of the Hand (ASSH) that use microsurgical techniques as part of their surgery practice, and second, to identify factors limiting their use of these techniques.

Methods: A 34-item, anonymous, Web-based survey was sent to all active ASSH members. Twelve items concerned demographics and 22 items addressed prior microsurgical training, current use of these techniques, factors currently limiting their use of these techniques, and potential methods to address these limiting factors.

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The precipitation of calcium carbonate as a binding salt for the consolidation of loose sand formations is a promising approach. The heterogeneous nucleation and growth of calcite were investigated in supersaturated solutions. The ionic activities in the solutions tested were selected so that they included both supersaturations in which crystal growth took place only following the introduction of seed particles and supersaturations in which precipitation occurred spontaneously past the lapse of induction times.

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The effect of four different polymers on the precipitation of calcium sulfate was investigated in the present work. The degree of inhibition was estimated from measurements of the calcium ion activity and from specific solution conductivity measurements in the supersaturated solutions during the course of the precipitation process. The effects of polyacrylic acid (PAA, three different polymers with average molecular weight 2000, 50,000, and 240,000, respectively) and of a co-polymer of PAA with polystyrene sulfonic acid (PSA, average molecular weight<20,000) were investigated with respect to their effect on the kinetics of spontaneous precipitation of calcium sulfate salts.

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In the past, the attitude toward surgical repair of sciatic and peroneal nerve lesions was excessively pessimistic. Refinements of microsurgical technique, nerve conduction studies, and the establishment of indications and optimal timings for surgical interventions have led to significant improvements in outcomes, making repair worthwhile in most cases. Tendon transfers can augment functional outcomes, and are performed as secondary procedures or (in selected cases) in combination with the initial repair.

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The adsorption of the widely used herbicide atrazine onto three model inorganic soil components (silica gel, gamma-alumina, and calcite (CaCO(3)) was investigated in a series of batch experiments in which the aqueous phase equilibrated with the solid, under different solution conditions. Atrazine did not show discernible adsorption on gamma-alumina (theta=25 degrees C, 3.8 View Article and Find Full Text PDF

Femoral neck fractures, frequently complicated by non-union and femoral head osteonecrosis,present a difficult clinical situation, especially when young patients are concerned. Existing treatment options are valgus osteotomy to address the biomechanical factors or bone grafting to address the biologic factor. The authors describe the operative technique and results of combined subtrochanteric valgus osteotomy and free vascularized fibular grafting in management of five young patients with both non-union and avascular necrosis.

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