The optimal treatment of type II and III odontoid fractures in the elderly: an updated meta-analysis.

PURPOSE: Odontoid fractures are the most common cervical spine fractures in the elderly, with a controversial optimal treatment. The objective of this review was to compare the outcome of surgical and conservative treatments in elderly (≥ 65 years), by updating a systematic review published by the authors in 2013. METHODS: A comprehensive search was conducted in seven databases. Clinical outcome was the primary outcome. Fracture union- and stability were secondary outcomes. Pooled point estimates and their respective 95% confidence intervals (CIs) were derived using the random-effects model. A random-effects multivariable meta-regression model was used to correct for baseline co-variates when sufficiently reported. RESULTS: Forty-one studies met the inclusion criteria, of which forty were case series and one a cohort study. No clinical differences in outcomes including the Neck Disability Index (NDI, 700 patients), Visual Analogue Scale pain (VAS, 180 patients), and Smiley-Webster Scale (SWS, 231 patients) scores were identified between surgical and conservative treatments. However, fracture union was higher in surgically treated patients (pooled incidence 72.7%, 95% CI 66.1%, 78.5%, 31 studies, 988 patients) than in conservatively treated patients (40.2%, 95% CI 32.0%, 49.0%, 22 studies, 912 patients). This difference remained after correcting for age and fracture type. Fracture stability (41 studies, 1917 patients), although numerically favoring surgery, did not appear to differ between treatment groups. CONCLUSION: While surgically treated patients showed higher union rates than conservatively treated patients, no clinically relevant differences were observed in NDI, VAS pain, and SWS scores and stability rates. These results need to be further confirmed in well-designed comparative studies with proper adjustment for confounding, such as age, fracture characteristics, and osteoporosis degree.

Spatiotemporal dynamics of oscillatory cellular patterns in three-dimensional directional solidification.

We report results of directional solidification experiments conducted on board the International Space Station and quantitative phase-field modeling of those experiments. The experiments image for the first time in situ the spatially extended dynamics of three-dimensional cellular array patterns formed under microgravity conditions where fluid flow is suppressed. Experiments and phase-field simulations reveal the existence of oscillatory breathing modes with time periods of several 10's of minutes. Oscillating cells are usually noncoherent due to array disorder, with the exception of small areas where the array structure is regular and stable.

Solidification furnace for in situ observation of bulk transparent systems and image analysis methods.

This paper aims to describe the experimental framework of the Directional Solidification Insert, installed onboard the International Space Station, dedicated to the in situ and real-time characterization of the dynamic selection of the solid-liquid interface morphology in bulk samples of transparent materials under diffusive growth conditions. The in situ observation of the solid-liquid interface is an invaluable tool for gaining knowledge on the time evolution of the interface pattern because the initial morphological instability evolves nonlinearly and undergoes a reorganization process. The result of each experiment, characterized by the sample concentration, a thermal gradient, and a pulling rate, is a large number of images. The interpretation of these images necessitates a robust identification of each cell/dendrite's position and size during the entire solidification. Several image analysis methods have been developed to reliably achieve this goal despite varying contrast and noise levels and are described in detail. Typical solidification experiments are presented, and the dynamics of the pattern formation are analyzed to illustrate the application of the image analysis methods.

Crack path selection in orientationally ordered composites.

While cracks in isotropic homogeneous materials propagate straight, perpendicularly to the tensile axis, cracks in natural and synthetic composites deflect from a straight path, often increasing the toughness of the material. Here we combine experiments and simulations to identify materials properties that predict whether cracks propagate straight or kink on a macroscale larger than the composite microstructure. Those properties include the anisotropy of the fracture energy, which we vary several fold by increasing the volume fraction of orientationally ordered alumina (Al_{2}O_{3}) platelets inside a polymer matrix, and a microstructure-dependent process zone size that is found to modulate the additional stabilizing or destabilizing effect of the nonsingular stress acting parallel to the crack. Those properties predict the existence of an anisotropy threshold for crack kinking and explain the surprisingly strong dependence of this threshold on sample geometry and load distribution.

Experimental characterization and theoretical analysis of cell tip oscillations in directional solidification.

Experiments performed in DECLIC-DSI on board the International Space Station evidenced oscillatory modes during the directional solidification of a bulk sample of succinonitrile-based transparent alloy. The interferometric data acquired during a reference experiment, V_{p}=1 µm/s and G=19 K/cm, allowed us to reconstruct the cell shape and thus measure the cell tip position, radius, and growth velocity evolution, in order to quantify the dynamics of the oscillating cells. This study completes our previous reports [Bergeon et al., Phys. Rev. Lett. 110, 226102 (2013)10.1103/PhysRevLett.110.226102; Tourret et al., Phys. Rev. E 92, 042401 (2015)10.1103/PhysRevE.92.042401; Pereda et al., Phys. Rev. E 95, 012803 (2017)10.1103/PhysRevE.95.012803] with, to our knowledge, the first complete monitoring of the geometric cell tip characteristics variations in bulk samples. The evolution of the shape, velocity, and position of the tip of the oscillating cells is associated with an evolution of the concentration field, inaccessible experimentally but mediating the diffusive interactions between the cells. The experimental results are supported by 3D phase-field simulations which evidence the existence of transversal solute fluxes between neighboring cells that play a fundamental role in the oscillation dynamics. The dynamics of oscillation of an individual cell is analyzed using a theoretical model based on classical equations of solidification through the calculation of the phase relationships between oscillation of the different tip characteristics.

Feedback control of unstable cellular solidification fronts.

We present a feedback control scheme to stabilize unstable cellular patterns during the directional solidification of a binary alloy. The scheme is based on local heating of cell tips which protrude ahead of the mean position of all tips in the array. The feasibility of this scheme is demonstrated using phase-field simulations and, experimentally, using a real-time image processing algorithm, to track cell tips, coupled with a movable laser spot array device to heat the tips locally. We demonstrate, both numerically and experimentally, that spacings well below the threshold for a period-doubling instability can be stabilized. As predicted by the numerical calculations, cellular arrays become stable with uniform spacing through the feedback control which is maintained with minimal heating.

Experimental observation of oscillatory cellular patterns in three-dimensional directional solidification.

We present a detailed analysis of oscillatory modes during three-dimensional cellular growth in a diffusive transport regime. We ground our analysis primarily on in situ observations of directional solidification experiments of a transparent succinonitrile 0.24wt% camphor alloy performed in microgravity conditions onboard the International Space Station. This study completes our previous reports [Bergeon et al., Phys. Rev. Lett. 110, 226102 (2013)10.1103/PhysRevLett.110.226102; Tourret et al., Phys. Rev. E 92, 042401 (2015)10.1103/PhysRevE.92.042401] from an experimental perspective, and results are supported by additional phase-field simulations. We analyze the influence of growth parameters, crystal orientation, and sample history on promoting oscillations, and on their spatiotemporal characteristics. Cellular patterns display a remarkably uniform oscillation period throughout the entire array, despite a high array disorder and a wide distribution of primary spacing. Oscillation inhibition may be associated to crystalline disorientation, which stems from polygonization and is manifested as pattern drifting. We determine a drifting velocity threshold above which oscillations are inhibited, thereby demonstrating that inhibition is due to cell drifting and not directly to disorientation, and also explaining the suppression of oscillations when the pulling velocity history favors drifting. Furthermore, we show that the array disorder prevents long-range coherence of oscillations, but not short-range coherence in localized ordered regions. For regions of a few cells exhibiting hexagonal (square) ordering, three (two) subarrays oscillate with a phase shift of approximately ±120^{∘} (180^{∘}), with square ordering occurring preferentially near subgrain boundaries.

Oscillatory cellular patterns in three-dimensional directional solidification.

We present a phase-field study of oscillatory breathing modes observed during the solidification of three-dimensional cellular arrays in microgravity. Directional solidification experiments conducted onboard the International Space Station have allowed us to observe spatially extended homogeneous arrays of cells and dendrites while minimizing the amount of gravity-induced convection in the liquid. In situ observations of transparent alloys have revealed the existence, over a narrow range of control parameters, of oscillations in cellular arrays with a period ranging from about 25 to 125 min. Cellular patterns are spatially disordered, and the oscillations of individual cells are spatiotemporally uncorrelated at long distance. However, in regions displaying short-range spatial ordering, groups of cells can synchronize into oscillatory breathing modes. Quantitative phase-field simulations show that the oscillatory behavior of cells in this regime is linked to a stability limit of the spacing in hexagonal cellular array structures. For relatively high cellular front undercooling (i.e., low growth velocity or high thermal gradient), a gap appears in the otherwise continuous range of stable array spacings. Close to this gap, a sustained oscillatory regime appears with a period that compares quantitatively well with experiment. For control parameters where this gap exists, oscillations typically occur for spacings at the edge of the gap. However, after a change of growth conditions, oscillations can also occur for nearby values of control parameters where this gap just closes and a continuous range of spacings exists. In addition, sustained oscillations at to the opening of this stable gap exhibit a slow periodic modulation of the phase-shift among cells with a slower period of several hours. While long-range coherence of breathing modes can be achieved in simulations for a perfect spatial arrangement of cells as initial condition, global disorder is observed in both three-dimensional experiments and simulations from realistic noisy initial conditions. In the latter case, erratic tip-splitting events promoted by large-amplitude oscillations contribute to maintaining the long-range array disorder, unlike in thin-sample experiments where long-range coherence of oscillations is experimentally observable.

Chlamydial antibodies in patients with previous acute anterior uveitis.

PURPOSE: To determine the prevalence of antibodies to Chlamydia pneumoniae, C. trachomatis, and C. pneumoniae heat shock protein (Cpn Hsp60) in patients with acute anterior uveitis (AAU) and in sex- and age-matched healthy control subjects. METHODS: Altogether 64 patients with previous AAU were examined at the Helsinki University Eye Hospital from September through December 1999. Serum specimens from the patients and sex- and age-matched healthy control subjects were tested for antibodies to C. pneumoniae and C. trachomatis by a specific microimmunofluorescence test and for antibodies to Cpn Hsp60 by enzyme immunoassay (EIA). RESULTS: The prevalence of antibodies to C. pneumoniae (69% vs. 72%) and C. trachomatis (11% vs. 6%) did not differ significantly between the patients and control subjects, nor did the level of IgG antibodies to Cpn Hsp60 (median EIA unit, 65 vs. 48). The levels of IgA antibodies to Cpn Hsp60 were significantly higher in the patients with AAU than in the control subjects (median EIA unit, 18 vs. 10; two-tailed Wilcoxon signed rank test, P = 0.0001). CONCLUSIONS: The high frequency of IgA antibodies to Cpn Hsp60 in patients with past AAU indicates that such patients may have persisting or recurrent infections due to C. pneumoniae. This finding suggests that C. pneumoniae may play a role in the pathogenesis of AAU.

Course and outcome of ocular sarcoidosis.

In a series of 281 patients with histologically confirmed sarcoidosis, 79 initially had ophthalmic sarcoid manifestations. Of 22 patients with uveitis, 21 were seen regularly as long as the inflammation was active, and 71 of the 79 patients (90%) underwent a follow-up study five to 16 years (mean, nine years) later and using the same protocol. In the 21 patients with uveitis, the disease exhibited either a monophasic course (eight patients) with favorable visual outcome or a relapsing course (13 patients) with severe visual loss in five eyes. Thirty-three patients showed chronic ophthalmic changes at the follow-up examination, including conjunctival granulomas (13 patients), lacrimal gland involvement (22 patients), uveitis (four patients), and involvement of lacrimal passages (three patients). In 15 of these 33 patients, the general physical examination and the chest x-ray showed no evidence of systemic sarcoidosis. However, the serum angiotensin converting enzyme level was increased in a significantly greater proportion of these 15 patients than in the patients assessed as totally recovered from sarcoidosis.

Diagnosis and clinical characteristics of ocular Lyme borreliosis.

PURPOSE: To establish a diagnosis, in a group of patients we studied the characteristics of ocular Lyme borreliosis. METHODS: During a two-year period, 236 patients with prolonged external ocular inflammation, uveitis, retinitis, optic neuritis, or unexplained neuro-ophthalmic symptoms were examined for Lyme borreliosis. Antibodies to Borrelia burgdorferi were measured by indirect ELISA and western blot. Cerebrospinal fluid was also analyzed by polymerase chain reaction. RESULTS: Ocular Lyme borreliosis was diagnosed in ten patients on the basis of medical history, clinical findings, and serologic test results. Results of ELISA disclosed that five patients were seropositive, two patients showed borderline reactivity, and three patients were seronegative. Four of the five patients with borderline or negative results by ELISA had a positive result by western blot analysis. In one seropositive patient, polymerase chain reaction verified a gene of B. burgdorferi endoflagellin from the vitreous and cerebrospinal fluid specimen. In five of the six patients with known onset of the Borrelia infection, the ocular disorder appeared as a late manifestation. Abnormalities of the posterior segment of the eye, such as vitreitis, retinal vasculitis, neuroretinitis, choroiditis, and optic neuropathy were seen in six patients. Bilateral paralytic mydriasis, interstitial keratitis, episcleritis, and anterior uveitis were seen in one patient each. CONCLUSIONS: Late-phase ocular Lyme borreliosis is probably underdiagnosed because of weak seropositivity or seronegativity in ELISA assays. Ocular borrelial manifestations show characteristics resembling those seen in syphilis.

HLA-B27 typing in the categorisation of uveitis in a HLA-B27 rich population.

AIMS: To determine whether HLA-B27 typing helps the clinician in the diagnostic examination of uveitis in a HLA-B27 rich population and also whether the clinical picture of HLA-B27 positive unilateral acute or recurrent anterior uveitis (AAU) is distinguishable from the idiopathic negative form. METHODS: During a 3 year period 220 consecutive patients with undetermined uveitis at onset were examined in the Helsinki University Eye Clinic. HLA-B27 antigen was tested for 85% of the patients. Other laboratory or x ray examinations were performed on the basis of the anatomical classification of uveitis and the biomicroscopic features characteristic of uveitis associated systemic diseases. RESULTS: HLA-B27 antigen was found significantly more often in patients with anterior (71%) and acute/recurrent unilateral (79%) uveitis than in patients with intermediate, posterior panuveitis (7%), and chronic (7%) or bilateral (12%) forms. Of the 16 cases of HLA-B27 negative unilateral AAU, five showed biomicroscopic features representing uveitis entities. The remaining 11 cases did not differ in any respect from the cases of HLA-B27 positive unilateral AAU. CONCLUSION: HLA-B27 antigen helps the clinician in the diagnostic examination of unilateral AAU. Positive test results serve as a clue to search for spondyloarthropathies, and negative results indicate the need to look for specific uveitis entities and other systemic diseases. The occurrence of HLA-B27 positivity in conjunction with uveitis entities other than unilateral AAU is of the same level or less than in the population of Finland in general.

Assessment of activity of ocular sarcoidosis by gallium scanning.

Gallium (67Ga) citrate uptake over the orbits, parotid glands, and lungs was examined in six newly detected patients with sarcoidosis and 17 with chronic sarcoidosis. Six of 23 (26%) had uveitis, 18/23 (78%) decreased lacrimal secretion, and 13/16 (81%) epithelioid cell granulomas in conjunctival biopsies. Ten patients with other diseases served as controls. Only five patients had ocular complaints and two had enlarged parotid glands. 67Ga uptake over the orbits and parotids was measured by a quantitative computer based method. Gallium uptake was significantly higher over the orbits (p less than 0.001) and parotids (p less than 0.01) in the newly detected patients and in the parotids (p less than 0.01) in the chronic group than the corresponding uptake in the controls. We suggest that in sarcoidosis an increased 67Ga uptake in the orbital and parotid areas may be a phenomenon comparable to an increased 67Ga uptake in the lungs in active alveolitis. Gallium scan is a good method for revealing even symptomless ophthalmic sarcoid changes. However, in chronic sarcoidosis an equal or only slightly increased gallium uptake over the orbits compared with background activity does not exclude ocular sarcoid disease.

Phenotypes of conjunctival inflammatory cells in sarcoidosis.

Phenotypes of the infiltrating mononuclear cells of the lower fornix conjunctiva of nine patients with sarcoidosis and six controls were studied using monoclonal antibodies and a modified immunoperoxidase method. Four patients had sarcoidosis of recent onset (duration of 2 years or less) and five patients had a chronic disease (duration of 3 or more years). The inflammatory cells in the sarcoid conjunctival specimens were predominantly T lymphocytes, the vast majority of which were of T helper/inducer subtype expressing Leu-3a + 3b positivity. The ratio of T helper/inducer cells to T suppressor/cytotoxic cells was 3.9 on average but only 0.9 in controls. Epithelioid cell granulomas were seen in three specimens in one case of recent onset and in two chronic cases comprising a marked amount (more than 15 cells/visual field) of cells bearing phenotypes of macrophages, T cells, T helper/inducer cells and HLA-DR antigen, and in smaller quantities of T suppressor/cytotoxic cells. The mean number of all immunocompetent cell subtypes of specimens from newly diagnosed patients exceeded that of specimens from chronic patients. We believe that the sarcoid immune reaction in the conjunctiva is a dynamic process in which proliferation of immunocompetent mononuclear cells precedes the stage of granuloma formation.

Secondary retinitis pigmentosa and cerebral demyelination in Lyme borreliosis.

A 15-year-old girl developed retinitis pigmentosa-like fundus changes in the left eye and optic neuropathy in the right eye as well as cerebral demyelination as a result of late Lyme borreliosis (LB). The diagnosis was confirmed by polymerase chain reaction, which detected a Borrelia burgdorferi specific segment of a gene coding for 41 kD endoflagellin, both in the vitreous and the cerebrospinal fluid. The diagnosis was delayed because testing for Borrelia antibodies in serum and cerebrospinal fluid yielded negative results. However, later on, another laboratory reported the antibodies of the patient's pretreatment serum to be positive for LB.

Systemic inflammation and innate immune response in patients with previous anterior uveitis.

AIM: To determine the presence of systemic inflammation and innate immune responsiveness of patients with a history of acute anterior uveitis but no signs of ocular inflammation at the time of recruitment. METHODS: Tumour necrosis factor alpha (TNF-alpha) production in response to bacterial lipopolysaccharide (LPS) was studied using whole blood culture assay; levels of TNF-alpha in culture supernatants, and soluble interleukin 2 receptor (sIL-2R) in serum were determined by chemiluminescent immunoassay (Immulite); monocyte surface expression of CD11b, CD14, and CD16 and the proportion of monocyte subsets CD14(bright)CD16(-) and CD14(dim)CD16(+) were studied with three colour whole blood flow cytometry; and serum C reactive protein (CRP) levels were determined using immunonephelometric high sensitivity CRP assay. RESULTS: The CRP level (median, interquartile range) was significantly higher in 56 patients with previous uveitis than in 37 controls (1.59 (0.63 to 3.47) microg/ml v 0.81 (0.32 to 2.09) microg/ml; p=0.008). The TNF-alpha concentration of the culture media per 10(5) monocytes was significantly higher in the patient group than in the control group in the presence of LPS 10 ng/ml (1473 (1193 to 2024) pg/ml v 1320 (935 to 1555) pg/ml; p=0.012) and LPS 1000 ng/ml (3280 (2709 to 4418) pg/ml v 2910 (2313 to 3358) pg/ml; p=0.011). The background TNF-alpha release into the culture media was low in both groups. CD14 expression of CD14(bright)CD16(-) monocytes, defined as antibody binding capacity (ABC), was similar for the patients and controls (22,839 (21,038 to 26,020) ABC v 21,657 (19,854 to 25,646) ABC). CONCLUSIONS: Patients with previous acute anterior uveitis show high innate immune responsiveness that may play a part in the development of ocular inflammation.

A population-based study on uveitis in juvenile rheumatoid arthritis.

OBJECTIVE: To obtain information on the occurrence and characteristics of uveitis in a population-based survey of patients with juvenile rheumatoid arthritis (JRA). METHODS: The subjects in this study were entitled, under the nationwide sickness insurance scheme, to receive specially reimbursed medication for JRA in 5 of the 21 central hospital districts in Finland (population base about 270,000 children < 16 years of age) in 1980, 1985 and 1990. RESULTS: A total of 114 incident cases (34 boys and 80 girls) satisfied the criteria for JRA. Uveitis was diagnosed in 18 of these patients (16%). The mean age of uveitis patients at the diagnosis of JRA was 6.8 years (median 5.4 years) and the mean interval from the diagnosis of JRA to the detection of uveitis was 2.9 years. Silent (asymptomatic) anterior uveitis was found in 4 boys and 11 girls and acute anterior uveitis in 2 boys. One girl had marginal corneal ulceration with mild anterior uveitis. Uveitis was chronic (> 6 months) in 9 cases. Uveal inflammation was most severe in the 3 children whose uveitis was detected at the time of the diagnosis of JRA. CONCLUSION: The study provides population-based information on the occurrence and characteristics of uveitis associated with JRA.

Pattern stability and trijunction motion in eutectic solidification.

We demonstrate by both experiments and phase-field simulations that lamellar eutectic growth can be stable for a wide range of spacings below the point of minimum undercooling at low velocity, contrary to what is predicted by existing stability analyses. This overstabilization can be explained by relaxing Cahn's assumption that lamellae grow locally normal to the eutectic interface.

Phase-field modeling of microstructural pattern formation during directional solidification of peritectic alloys without morphological instability.

During the directional solidification of peritectic alloys, two stable solid phases (parent and peritectic) grow competitively into a metastable liquid phase of larger impurity content than either solid phase. When the parent or both solid phases are morphologically unstable, i.e., for a small temperature gradient/growth rate ratio (G/v(p)), one solid phase usually outgrows and covers the other phase, leading to a cellular-dendritic array structure closely analogous to the one formed during monophase solidification of a dilute binary alloy. In contrast, when G/v(p) is large enough for both phases to be morphologically stable, the formation of the microstructure becomes controlled by a subtle interplay between the nucleation and growth of the two solid phases. The structures that have been observed in this regime (in small samples where convection effects are suppressed) include alternate layers (bands) of the parent and peritectic phases perpendicular to the growth direction, which are formed by alternate nucleation and lateral spreading of one phase onto the other as proposed in a recent model [R. Trivedi, Metall. Mater. Trans. A 26, 1 (1995)], as well as partially filled bands (islands), where the peritectic phase does not fully cover the parent phase which grows continuously. We develop a phase-field model of peritectic solidification that incorporates nucleation processes in order to explore the formation of these structures. Simulations of this model shed light on the morphology transition from islands to bands, the dynamics of spreading of the peritectic phase on the parent phase following nucleation, which turns out to be characterized by a remarkably constant acceleration, and the types of growth morphology that one might expect to observe in large samples under purely diffusive growth conditions.

Phase-field simulations of dendritic crystal growth in a forced flow.

Convective effects on free dendritic crystal growth into a supercooled melt in two dimensions are investigated using the phase-field method. The phase-field model incorporates both melt convection and thermal noise. A multigrid method is used to solve the conservation equations for flow. To fully resolve the diffuse interface region and the interactions of dendritic growth with flow, both the phase-field and flow equations are solved on a highly refined grid where up to 2.1 million control volumes are employed. A multiple time-step algorithm is developed that uses a large time step for the flow-field calculations while reserving a fine time step for the phase-field evolution. The operating state (velocity and shape) of a dendrite tip in a uniform axial flow is found to be in quantitative agreement with the prediction of the Oseen-Ivantsov transport theory if a tip radius based on a parabolic fit is used. Furthermore, using this parabolic tip radius, the ratio of the selection parameters without and with flow is shown to be close to unity, which is in agreement with linearized solvability theory for the ranges of the parameters considered. Dendritic sidebranching in a forced flow is also quantitatively studied. Compared to a dendrite growing at the same supercooling in a diffusive environment, convection is found to increase the amplitude and frequency of the sidebranches. The phase-field results for the scaled sidebranch amplitude and wavelength variations with distance from the tip are compared to linear Wentzel-Kramers-Brillouin theory. It is also shown that the asymmetric sidebranch growth on the upstream and downstream sides of a dendrite arm growing at an angle with respect to the flow can be explained by the differences in the mean shapes of the two sides of the arm.