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Sample records for fractured slab techniques

  1. May eclogite dehydration cause slab fracturation ?

    NASA Astrophysics Data System (ADS)

    Loury, Chloé; Lanari, Pierre; Rolland, Yann; Guillot, Stéphane; Ganino, Clément

    2015-04-01

    prograde path, leading to a complete dehydration at the pressure peak conditions, (25 kbar and 510°C). The amount of water released during this stage is about 20 g/dm3. In this example, no hydration event is recorded during the exhumation, explaining the good preservation of the anhydrous eclogite. This study shows that garnet thermobarometry in eclogite may be used as a proxy for progressive oceanic crust dehydration as suggested by the models of Baxter & Caddick (2014). In contrast to such models, the estimations proposed in the present study are based on the measured composition of local domains in rock-samples and not on average bulk rock compositions. Complete dehydration of eclogites around 75 km corresponds to the maximum depth of most exhumed oceanic eclogites except for a few special cases. Moreover the distribution of seismicity along the slab shows that only few earthquakes do occur in the crust beyond this limit as compared to the seismicity above it. Consequently this example from a natural sample strongly suggests that the eclogite dehydration at this depth can cause slab fracturation and consequently enhance eclogite exhumation. Baxter, E.F. & Caddick, M.J. 2013. Garnet growth as a proxy for progressive subduction zone dehydration. Geology, 41, 643-646 Lanari, P., Vidal, O., De Andrade, V., Dubacq, B., Lewin, E., Grosch, E.G. & Schwartz, S. 2014. XMapTools: A MATLAB©-based program for electron microprobe X-ray image processing and geothermobarometry. Computers & Geosciences, 62, 227-240 Loury, C., Rolland, Y., Guillot, S., Mikolaichuk, A., Lanari, P., Bruguier, O. & Bosch, D. in press. Crustal-scale structure of South Tien Shan : implications for subduction polarity and Cenozoic reactivation. Geological Society of London, special publications

  2. Subduction of fracture zones controls mantle melting and geochemical signature above slabs.

    PubMed

    Manea, Vlad C; Leeman, William P; Gerya, Taras; Manea, Marina; Zhu, Guizhi

    2014-01-01

    For some volcanic arcs, the geochemistry of volcanic rocks erupting above subducted oceanic fracture zones is consistent with higher than normal fluid inputs to arc magma sources. Here we use enrichment of boron (B/Zr) in volcanic arc lavas as a proxy to evaluate relative along-strike inputs of slab-derived fluids in the Aleutian, Andean, Cascades and Trans-Mexican arcs. Significant B/Zr spikes coincide with subduction of prominent fracture zones in the relatively cool Aleutian and Andean subduction zones where fracture zone subduction locally enhances fluid introduction beneath volcanic arcs. Geodynamic models of subduction have not previously considered how fracture zones may influence the melt and fluid distribution above slabs. Using high-resolution three-dimensional coupled petrological-thermomechanical numerical simulations of subduction, we show that enhanced production of slab-derived fluids and mantle wedge melts concentrate in areas where fracture zones are subducted, resulting in significant along-arc variability in magma source compositions and processes. PMID:25342158

  3. Subduction of fracture zones controls mantle melting and geochemical signature above slabs

    NASA Astrophysics Data System (ADS)

    Manea, Vlad C.; Leeman, William P.; Gerya, Taras; Manea, Marina; Zhu, Guizhi

    2014-10-01

    For some volcanic arcs, the geochemistry of volcanic rocks erupting above subducted oceanic fracture zones is consistent with higher than normal fluid inputs to arc magma sources. Here we use enrichment of boron (B/Zr) in volcanic arc lavas as a proxy to evaluate relative along-strike inputs of slab-derived fluids in the Aleutian, Andean, Cascades and Trans-Mexican arcs. Significant B/Zr spikes coincide with subduction of prominent fracture zones in the relatively cool Aleutian and Andean subduction zones where fracture zone subduction locally enhances fluid introduction beneath volcanic arcs. Geodynamic models of subduction have not previously considered how fracture zones may influence the melt and fluid distribution above slabs. Using high-resolution three-dimensional coupled petrological-thermomechanical numerical simulations of subduction, we show that enhanced production of slab-derived fluids and mantle wedge melts concentrate in areas where fracture zones are subducted, resulting in significant along-arc variability in magma source compositions and processes.

  4. Frozen-slab technique for mixing zinc phosphate cement for cast restorations.

    PubMed

    Newman, S M

    1980-01-01

    The technique for handling zinc phosphate cement can be altered to achieve enhanced properties of the cement. The compressive strength of the material can be decreased. The film thickness can be maintained within acceptable limits, and the possibility of pulpal damage can be kept low by maintaining temperature changes in the cement similar to those obtained from a room temperature-slab technique. The technique advocated by this report is as follows: 1. Store the aluminum slab with vinyl covering in a freezer at -15 degrees C to -20 degrees C in a plastic bag to prevent ice formation on the surface. 2. Remove the slab when ready to mix. 3. Quickly wipe the slab clean. 4. Dispense twice as much powder and liquid as recommended on the slab. 5. Start timer. 6. Slowly incorporate the powder into the liquid over a large area of the slab for 2 minutes. 7. Allow the mix to remain on the slab. 8. The instrument for placing the cement can be placed under the slab. The casting can be placed on a corner of the slab. 9. At 10 minutes, place the cement into the casting(s) and seat. 10. Remove excess cement. 11. Clean the slab by rinsing in water and gently wiping. 12. Dry the slab, place it in the plastic bag, and return it to the freezer. PMID:6927907

  5. Fracture problem of a nonhomogeneous high temperature superconductor slab based on real fundamental solutions

    NASA Astrophysics Data System (ADS)

    Gao, Zhiwen; Zheng, Zhiye; Li, Xueyi

    2015-12-01

    To analyze the fracture problem of the nonhomogeneous high temperature superconductor (HTS) slab under electromagnetic force, we derive the real fundamental solutions based on eigenvalue and eigenvector analyses. The superconductor E-J constitutive law is characterized by the Bean model where the critical current density is independent of the flux density. Fracture analysis is performed by the methods of singular integral equations which are solved numerically by Lobatto-Chybeshev collocation method. Numerical results of the stress intensity factor (SIF) are obtained. Moreover, the crack opening displacement (COD) can be obtained by numerical integration dislocation density functions. The effects of the thickness ratio, HTS material nonhomogeneous parameters, applied magnetic field and critical current density on SIF and COD are discussed. The present work could theoretically provide quantitative predictions of the fracture mechanism of the nonhomogeneous HTS.

  6. Subduction of Fracture Zones control mantle melting and geochemical signature above slabs

    NASA Astrophysics Data System (ADS)

    Constantin Manea, Vlad; Leeman, William; Gerya, Taras; Manea, Marina; Zhu, Guizhi

    2014-05-01

    The geochemistry of arc volcanics proximal to oceanic fracture zones (FZs) is consistent with higher than normal fluid inputs to arc magma sources. Here, enrichment of boron (B/Zr) in volcanic arc lavas is used to evaluate relative along-strike inputs of slab-derived fluids in the Aleutian, Andean, Cascades, and Trans-Mexican arcs. Significant B/Zr spikes coincide with subduction of prominent FZs in the relatively cool Aleutian and Andean subduction zones, but not in the relatively warm Cascadia and Mexican subduction zones, suggesting that FZ subduction locally enhances fluid introduction beneath volcanic arcs, and retention of fluids to sub-arc depths diminishes with subduction zone thermal gradient. Geodynamic treatments of lateral inhomogeneities in subducting plates have not previously considered how FZs may influence the melt and fluid distribution above the slab. Using high-resolution three-dimensional coupled petrological-thermomechanical numerical simulations of subduction, we show that fluids, including melts and water, concentrate in areas where fracture zones are subducted, resulting in along-arc variability in magma source compositions and processes.

  7. Application techniques for plaster of paris back slab, resting splint, and thumb spica using ridged reinforcement.

    PubMed

    Chow, Jason; Hsu, Shelly; Kwok, Daniel; Reagh, Jessica

    2013-09-01

    Immobilization of fractures with plaster of Paris is a mainstay of management of stable, nondisplaced fractures not requiring fixation. However, application techniques can be variable and are often ineffective after the patient is discharged because of weakness and wear of the plaster. This can lead to displacement of fractures and inadequate analgesia. We describe a simple, inexpensive, effective technique to ensure plaster strength and immobilization. PMID:23657008

  8. Imaging the slab beneath central Chile using the Spectral Elements Method and adjoint techniques

    NASA Astrophysics Data System (ADS)

    Mercerat, E. D.; Nolet, G.; Marot, M.; Deshayes, P.; Monfret, T.

    2010-12-01

    This work focuses on imaging the subducting slab beneath Central Chile using novel inversion techniques based on the adjoint method and accurate wave propagation simulations using the Spectral Elements Method. The study area comprises the flat slab portion of the Nazca plate between 29 S and 34 S subducting beneath South America. We will use a database of regional seismicity consisting of both crustal and deep slab earthquakes with magnitude 3 < Mw < 6 recorded by different temporary and permanent seismological networks. Our main goal is to determine both the kinematics and the geometry of the subducting slab in order to help the geodynamical interpretation of such particular active margin. The Spectral Elements Method (SPECFEM3D code) is used to generate the synthetic seismograms and it will be applied for the iterative minimization based on adjoint techniques. The numerical mesh is 600 km x 600 km in horizontal coordinates and 220 km depth. As a first step, we are faced to well-known issues concerning mesh generation (resolution, quality, absorbing boundary conditions). In particular, we must evaluate the influence of free surface topography, as well as the MOHO and other geological interfaces in the synthetic seismograms. The initial velocity model from a previous travel-time tomography study, is linearly interpolated to the Gauss-Lobatto-Legendre grid. The comparison between the first forward simulations (up to 4 seconds minimum period) validate the initial velocity model of the study area, although many features not reproduced by the initial model have already been identified. Next step will concentrate in the comparison between finite-frequency kernels calculated by travel-time methods with ones based on adjoint methods, in order to highlight advantages and disadvantages in terms of resolution, accuracy, but also computational cost.

  9. Techniques for increasing boron fiber fracture strain

    NASA Technical Reports Server (NTRS)

    Dicarlo, J. A.

    1977-01-01

    Improvement in the strain-to-failure of CVD boron fibers is shown possible by contracting the tungsten boride core region and its inherent flaws. The results of three methods are presented in which etching and thermal processing techniques were employed to achieve core flaw contraction by internal stresses available in the boron sheath. After commercially and treatment induced surface flaws were removed from 203 micrometers (8 mil) fibers, the core flaw was observed to be essentially the only source of fiber fracture. Thus, fiber strain-to-failure was found to improve by an amount equal to the treatment induced contraction on the core flaw. Commercial feasibility considerations suggest as the most cost effective technique that method in which as-produced fibers are given a rapid heat treatment above 700 C. Preliminary results concerning the contraction kinetics and fracture behavior observed are presented and discussed both for high vacuum and argon gas heat treatment environments.

  10. Analysis of mode scattering from an abruptly ended dielectric slab waveguide by an accelerated iteration technique.

    PubMed

    Tigelis, I G; Manenkov, A B

    2000-12-01

    A new modification of the integral equation method using an iteration technique with "accelerating" parameters is presented to solve the problem of guided-mode scattering from an abruptly ended asymmetrical slab waveguide. The optimal choice of the parameters is shown to be closely connected with the variational principle. The electric-field distribution at the terminal plane, the reflection coefficient of the guided mode, and the far-field radiation pattern are computed. Numerical results are presented for several cases of abruptly ended waveguides, including the systems with constant and variable profiles of the refractive indices. The phenomenon of the radiation pattern rotation is examined in detail. PMID:11140485

  11. Element fracture technique for hypervelocity impact simulation

    NASA Astrophysics Data System (ADS)

    Zhang, Xiao-tian; Li, Xiao-gang; Liu, Tao; Jia, Guang-hui

    2015-05-01

    Hypervelocity impact dynamics is the theoretical support of spacecraft shielding against space debris. The numerical simulation has become an important approach for obtaining the ballistic limits of the spacecraft shields. Currently, the most widely used algorithm for hypervelocity impact is the smoothed particle hydrodynamics (SPH). Although the finite element method (FEM) is widely used in fracture mechanics and low-velocity impacts, the standard FEM can hardly simulate the debris cloud generated by hypervelocity impact. This paper presents a successful application of the node-separation technique for hypervelocity impact debris cloud simulation. The node-separation technique assigns individual/coincident nodes for the adjacent elements, and it applies constraints to the coincident node sets in the modeling step. In the explicit iteration, the cracks are generated by releasing the constrained node sets that meet the fracture criterion. Additionally, the distorted elements are identified from two aspects - self-piercing and phase change - and are deleted so that the constitutive computation can continue. FEM with the node-separation technique is used for thin-wall hypervelocity impact simulations. The internal structures of the debris cloud in the simulation output are compared with that in the test X-ray graphs under different material fracture criteria. It shows that the pressure criterion is more appropriate for hypervelocity impact. The internal structures of the debris cloud are also simulated and compared under different thickness-to-diameter ratios (t/D). The simulation outputs show the same spall pattern with the tests. Finally, the triple-plate impact case is simulated with node-separation FEM.

  12. Subcritical measurements of the WINCO slab tank experiment using the source-jerk technique

    SciTech Connect

    Spriggs, G.D.; Hansen, G.E.; Martin, E.R.; Plassmann, E.A.; Pederson, R.A.; Schlesser, J.A.; Krawczyk, T.L.; Tanner, J.E.; Smolen, G.R.; Martin Marietta Energy Systems, Inc., Oak Ridge, TN; Westinghouse Idaho Nuclear Co., Inc., Idaho Falls, ID; Martin Marietta Energy Systems, Inc., Oak Ridge, TN )

    1989-01-01

    Subcritical measurements of the WINCO slab tank using the source-jerk technique are presented. This technique determines subcriticality by analyzing the transient response produced by the sudden removal of an extraneous neutron source (i.e., a source jerk). We have found that the technique can provide an accurate means of measuring k in configurations that are close to critical (i.e., 0.90 < k < 1.0). As the system becomes more subcritical (i.e., k < 0.90), spatial effects introduce significant biases depending on the source and detector positions. A comparison between the measurements and Monte Carlo code calculations is also presented. 15 refs., 6 figs., 2 tabs.

  13. Sliding interleaved kY (SLINKY) acquisition: a novel 3D MRA technique with suppressed slab boundary artifact.

    PubMed

    Liu, K; Rutt, B K

    1998-01-01

    This work addresses the elimination of the slab boundary artifact (SBA) or venetian blind artifact in three-dimensional multiple overlapped thin slab acquisition (3D MOTSA) for magnetic resonance angiography (MRA). Our method uses a sliding-slab, interleaved kY (SLINKY) data acquisition strategy, equalizing flow-related signal intensity weighting across the entire slab dimension. This technique demodulates signal intensity changes along the slab direction and can essentially eliminate the SBA while retaining the same or better imaging time efficiency than that of conventional MOTSA, providing robustness to complicated flow patterns and thereby resulting in more accurate depiction of vascular morphology. In addition, this technique does not need specialized reconstruction and extra computation. The unique penalty of this technique is the sensitivity to phase inconsistency in the data. Both phantom and in vivo experiments verify the clinical significance of the technique. The new MRA images acquired with this imaging technique show highly reliable mapping of vascular morphology without the SBA and reduction of signal voids in complex/slow flow regions. PMID:9702893

  14. Fracture detection in crystalline rock using ultrasonic reflection techniques: Volume 1

    SciTech Connect

    Palmer, S.P. )

    1982-11-01

    This research was initiated to investigate using ultrasonic seismic reflection techniques to detect fracture discontinuities in a granitic rock. Initial compressional (P) and shear (SH) wave experiments were performed on a 0.9 {times} 0.9 {times} 0.3 meter granite slab in an attempt to detect seismic energy reflected from the opposite face of the slab. It was found that processing techniques such as deconvolution and array synthesis could improve the standout of the reflection event. During the summers of 1979 and 1980 SH reflection experiments were performed at a granite quarry near Knowles, California. The purpose of this study was to use SH reflection methods to detect an in situ fracture located one to three meters behind the quarry face. These SH data were later analyzed using methods similar to those applied in the laboratory. Interpretation of the later-arriving events observed in the SH field data as reflections from a steeply-dipping fracture was inconclusive. 41 refs., 43 figs., 7 tabs.

  15. Microwave Quantitative NDE Technique for Dielectric Slab Thickness Estimation Using the Music Algorithm

    NASA Astrophysics Data System (ADS)

    Abou-Khousa, M. A.; Zoughi, R.

    2007-03-01

    Non-invasive monitoring of dielectric slab thickness is of great interest in various industrial applications. This paper focuses on estimating the thickness of dielectric slabs, and consequently monitoring their variations, utilizing wideband microwave signals and the MUtiple SIgnal Characterization (MUSIC) algorithm. The performance of the proposed approach is assessed by validating simulation results with laboratory experiments. The results clearly indicate the utility of this overall approach for accurate dielectric slab thickness evaluation.

  16. Suture Bridge Fixation Technique for Posterior Cruciate Ligament Avulsion Fracture

    PubMed Central

    Lee, Kwang Won; Lee, Gyu Sang; Choy, Won Sik

    2015-01-01

    We presented a surgical technique including a suture bridge technique with relatively small incision for the reduction and fixation of posterior ligament avulsion fractures. A suture anchor was used to hold the avulsed fragment and a knotless anchor was used to continuously compress the bony fragment into the fracture site, thereby maintaining reduction during healing. PMID:26640635

  17. Improving clinical examination in acute tibial fractures by enhancing visual cues: the case for always 'cutting back' a tibial back-slab and marking the dorsalis pedis pulse.

    PubMed

    Thomas, Alasdair; Kimber, Cheryl; Bramwell, Donald; Jaarsma, Ruurd

    2016-08-01

    Look, feel, move is a simple and widely taught sequence to be followed when undertaking a clinical examination in orthopaedics (Maher et al., 1994; McRae, 1999; Solomon et al., 2010). The splinting of an acute tibial fracture with a posterior back-slab is also common practice; with the most commonly taught design involving covering the dorsum of the foot with bandaging (Charnley, 1950; Maher et al., 1994; McRae, 1989). We investigated the effect of the visual cues provided by exposing the dorsum of the foot and marking the dorsalis pedis pulse. We used a clinical simulation in which we compared the quality of the recorded clinical examination undertaken by 30 nurses. The nurses were randomly assigned to assess a patient with either a traditional back-slab or one in which the dorsal bandaging had been cut back and the dorsalis pedis pulse marked. We found that the quality of the recorded clinical examination was significantly better in the cut-back group. Previous studies have shown that the cut-back would not alter the effectiveness of the back-slab as a splint (Zagorski et al., 1993). We conclude that all tibial back-slabs should have the bandaging on the dorsum of the foot cut back and the location of the dorsalis pedis pulse marked. This simple adaptation will improve the subsequent clinical examinations undertaken and recorded without reducing the back-slab's effectiveness as a splint. PMID:27236718

  18. Use of fractography and sectioning techniques to study fracture mechanisms

    NASA Technical Reports Server (NTRS)

    Van Stone, R. H.; Cox, T. B.

    1976-01-01

    Recent investigations of the effect of microstructure on the fracture mechanisms and fracture toughness of steels, aluminum alloys, and titanium alloys have used standard fractographic techniques and a sectioning technique on specimens plastically deformed to various strains up to fracture. The specimens are prepared metallographically for observation in both optical and electron beam instruments. This permits observations to be made about the fracture mechanism as it occurs in thick sections and helps remove speculation from the interpretation of fractographic features. This technique may be used in conjunction with other standard techniques such as extraction replicas and microprobe analyses. Care must be taken to make sure that the microstructural features which are observed to play a role in the fracture process using the sectioning technique can be identified with fractography.

  19. Feasibility of a borehole VHF radar technique for fracture mapping

    SciTech Connect

    Chang, H.T.

    1984-01-01

    Experiments were conducted to establish the feasibility of a downhole high-frequency electromagnetic technique for location of fractures in the vicinity of boreholes. An existing flame-cut slot in granite was filled with salt water to simulate a brine-filled fracture. A transmitter consisting of a phased dual-dipole array arranged to provide a directional signal toward the fracture was installed in a borehole opposite the fracture. A receiver operated at 30 to 300 MHz was also located in the same borehole. The radar returns from the simulated fracture were detectable in boreholes located at distances of up to 12 meters from the fracture. These results indicate for the first time the feasibility of a downhole VHF radar for use in a single borehole for detection of fractures located away from the borehole.

  20. New technique for fixing rib fracture with bioabsorbable plate.

    PubMed

    Oyamatsu, Hironori; Ohata, Norihisa; Narita, Kunio

    2016-09-01

    Fixation of a bone fracture with a bioabsorbable plate made of poly-L-lactide and hydroxyapatite has received attention. We adopted this technique for a rib fracture by bending the plate into a U-shape and fixing it with suture through the holes in the mesh of the plate and holes that are drilled in the edge of the fractured rib. The suture is also wound around the plate. PMID:27206779

  1. A minimally invasive surgical technique to treat distal clavicle fractures.

    PubMed

    Swanson, Kyle E; Swanson, Britta L

    2009-07-01

    Treatment of distal clavicle fractures ranges from nonoperative to operative approaches. Various surgical procedures have been described in the literature, each with potential complications. For fractures treated operatively, the goal is to maximize stability and functionality while minimizing pain and deformity. This article describes a double-button suture system using a mini-open technique to repair a distal clavicle fracture providing stable fixation with minimal disruption of the surrounding anatomy. PMID:19634845

  2. Modelling fracture orientations in reservoirs with photo-elastic techniques

    SciTech Connect

    Rawnsley, K.; Auzias, V.; Petit, J.P.

    1995-08-01

    Fractures within a reservoir can be divided into two types: faults, which result from shear displacement, and tension fractures which result from opening mode displacement. Tension fractures develop perpendicular to the minimal principal stress and so represent an image of the stress field orientation prevailing during their development. In reservoirs tension fractures are not observed by standard seismic techniques and can only be observed very locally in core or suitable well bore images. Frequently tension fracture orientations vary within and between wells. For this reason the extrapolation of tension fracture orientations between wells can be complicated. We present a method based on photo-elastic techniques that can model complex tension fracture patterns. Photo-elastic techniques permit the modelling of a stress field in a faulted strata and have shown that variations in tension fracture orientation may often be linked to stress field perturbations due to faults. The photo-elastic model consists of a rectangular plate of transparent polymer into which narrow slots with various frictional properties can be engineered to represent faults. The plate is loaded in a compression cell and light is transmitted through the plate via two polarizers and the directions of the stress field trajectories can be determined. Applications of photo-elastic modelling of tension fracture orientations to both outcrop and reservoir data are presented. The reservoir example consists of a horizontal well with continuous fracture data obtained from core and Formation Micro-Scanner logs. It is shown that the stress field at the seismic fault scale can be related to the large scale variations in the fracture pattern in the well. Smaller scale variations in the well fracture orientations are simulated by down scaling the photo-elastic model from seismic scale faults to include mostly sub-seismic faults near the well.

  3. Application of endoscopic techniques in orbital blowout fractures.

    PubMed

    Zhang, Shu; Li, Yinwei; Fan, Xianqun

    2013-09-01

    Minimally invasive surgical techniques, particularly endoscopic techniques, have revolutionized otolaryngeal surgery. Endoscopic techniques have been gradually applied in orbital surgery through the sinus inferomedial to the orbit and the orbital subperiosteal space. Endoscopic techniques help surgeons observe fractures and soft tissue of the posterior orbit to precisely place implants and protect vital structures through accurate, safe, and minimally invasive approaches. We reviewed the development of endoscopic techniques, the composition of endoscopic systems for orbital surgery, and the problems and developmental prospects of endoscopic techniques for simple orbital wall fracture repair. PMID:23794028

  4. Novel venting technique for intramedullary rod fixation of pathologic fractures.

    PubMed

    Wilkens, Kenneth J; Nicolaou, Daemeon A M; Lee, Mark A

    2011-10-01

    This article introduces a novel technique to vent the femur and potentially decrease the embolic load created by reaming during intramedullary rod fixation of impending pathologic femur fractures. We used readily available operating room equipment to create a distal femoral vent hole without interfering with standard intramedullary instrumentation and with minimal increase in surgical time. This technique can be used for the prophylactic intramedullary stabilization of impending pathologic femur fractures from metabolic bone disease, metastatic cancer, and bisphosphonate use. PMID:21956178

  5. A technique for removal of a fractured implant abutment screw.

    PubMed

    Kurt, Murat; Güler, Ahmet Umut; Duran, İbrahim

    2013-12-01

    The aim of this technique report was to present a procedure for removal of a fractured implant abutment screw. Whatever the cause, when an abutment fracture has occurred, the fractured screw segment inside the implant must be removed. The methods used by the clinicians may include the use of an endo-explorer self-made screwdriver and the use of implant repair kit available for some implant systems. The advantage of the presented method is that it may be extended to other implant systems that do not have a special repair kit and also that the technique is simple and does not require special equipment. PMID:21905898

  6. Re-attachment of anterior fractured teeth: fracture strength using different techniques.

    PubMed

    Reis, A; Francci, C; Loguercio, A D; Carrilho, M R; Rodriques Filho, L E

    2001-01-01

    Fracture of anterior teeth by trauma is a common problem in children and teenagers. Complex metal-ceramic crowns with considerable loss of remaining sound structure are no longer necessary due to adhesive techniques, such as composite restorations and re-attachment techniques. This study compared the fracture strength of sound and restored anterior teeth using a resin composite and four re-attachment techniques. A "one bottle" adhesive system (One-Step, BISCO) and a dual cure resin cement (Duo-Link, BISCO) were applied. Thirty-five sound permanent lower central incisors were fractured by an axial load applied to the buccal area and randomly divided into five groups. The teeth were restored as follows: 1) bonded only = just bonding the fragment; 2) chamfer-group = after bonding, a chamfer was prepared on the enamel at the bonding line and filled with composite; 3) overcontour group = after bonding, a thin composite overcontour was applied on the buccal surface around the fracture line; 4) internal dentinal groove = before bonding, an internal groove was made and filled with a resin composite; 5) resin composite group = after a bevel preparation on the enamel edge, the adhesive system was applied and the fractured part of the teeth rebuilt by resin composite. Restored teeth were subjected to the same loading in the same buccal area. Fracture strength after restorative procedure was expressed as a percentage of the original fracture strength and the results analyzed by Kruskal-Wallis statistical analysis. The mean percentages of fracture strength were: Group 1: 37.09%, Group 2: 60.62%, Group 3: 97.2%, Group 4: 90.54% and Group 5: 95.8%. It was concluded that the re-attachment techniques used in Groups 3 and 4, as well as the composite restored group (Group 5), were statistically similar and reached the highest fracture resistance, similar to the fracture resistance of sound teeth. PMID:11357572

  7. The use of augmentation techniques in osteoporotic fracture fixation.

    PubMed

    Kammerlander, Christian; Neuerburg, Carl; Verlaan, Jorrit-Jan; Schmoelz, Werner; Miclau, Theodore; Larsson, Sune

    2016-06-01

    There are an increasing number of fragility fractures, which present a surgical challenge given the reduced bone quality of underlying osteoporosis. Particularly in aged patients, there is a need for early weight bearing and mobilization to avoid further complications such as loss of function or autonomy. As an attempt to improve fracture stability and ultimate healing, the use of biomaterials for augmentation of osseous voids and fracture fixation is a promising treatment option. Augmentation techniques can be applied in various locations, and fractures of the metaphyseal regions such as proximal humerus, femur, tibia and the distal radius remain the most common areas for its use. The current review, based on the available mechanical and biological data, provides an overview of the relevant treatment options and different composites used for augmentation of osteoporotic fractures. PMID:27338226

  8. [Nailing of inter- and subtrochanteric fractures - operative technique].

    PubMed

    Douša, P; Skála-Rosenbaum, J

    2013-10-01

    Intertrochanteric and subtrochanteric fractures are a quite heterogeneous and imprecisely defined group of fractures. These fractures can be essentially divided into two basic groups. The first one belongs to trochanteric fractures. In the AO/ASIF classification; these fractures are called intertrochanteric (31A3). In the second group, the term subtrochanteric fracture is used by most authors for fractures about 5 cm distally from lesser trochanter. In both intertrochanteric and subtrochanteric fractures, the proximal fragment is formed by femoral head, neck and greater trochanter including its base with vastus ridge (tuberculum vastoadductorium or innominate tubercle). On this tubercle, the gluteus medius muscle (proximally) and the origin of the vastus lateralis muscle (distally) are attached. Tension of these muscles may cause dislocation of the proximal fragment. For this reason, reduction of the fracture can be troublesome and it is more difficult than in pertrochanteric fractures It seems that intramedullary nailing will remain the favorite technique of most of the surgeons dealing with intertrochanteric and subtrochanteric fractures. We use short reconstruction nail in intertrochanteric fractures. It is useful to use long reconstruction nail in subtrochanteric fractures. Distal locking of the nail is necessary. Dynamic distal locking is preferred because the two main fragments are compressed along the axis of the nail. The number of complications was largely related to technical errors, such as insufficient reduction or an incorrectly inserted implant. No implant can compensate for errors due to surgery. Serious complications can be reduced by the correct assessment of fracture type, the use of an appropriate operative technique and early treatment of potential complications. The necessity of restoring continuity in the medial cortex of the femoral neck (Adams arch) is the requirement that should be observed. Pseudoarthrosis or varus malalignment in a healed

  9. Tuberoplasty: minimally invasive osteosynthesis technique for tibial plateau fractures.

    PubMed

    Vendeuvre, T; Babusiaux, D; Brèque, C; Khiami, F; Steiger, V; Merienne, J-F; Scepi, M; Gayet, L E

    2013-06-01

    Fractures of the tibial plateau are in constant progression. They affect an elderly population suffering from a number of comorbidities, but also a young population increasingly practicing high-risk sports and using two-wheeled vehicles. The objective of this study was therefore to propose a new technique for the treatment of this type of fracture. There are a variety of classical pitfalls of conservative treatment such as defective reduction resulting in early osteoarthritis and alignment defects. Conventional treatments lead to joint stiffness and amyotrophy of the quadriceps, caused by the open technique and late loading. We propose an osteosynthesis technique for tibial plateau fractures with minimally invasive surgery. A minimally invasive technique would be more appropriate to remedy all of the surgical drawbacks resulting from current practices. The surgical technique that we propose uses a balloon allowing progressive and total reduction, associated with percutaneous screw fixation and filling with polymethylmethacrylate (PMMA) cement. The advantages are optimal reduction, minimal devascularization, soft tissues kept intact, as well as early loading and mobilization. This simple technique seems to be a good alternative to conventional treatment. The most comminuted fractures as well as the most posterior compressions can be treated, while causing the least impairment possible. Arthroscopy can be used to verify fracture reduction and cement leakage. At the same time, it can be used to assess the associated meniscal lesions and to repair them if necessary. PMID:23622864

  10. Technical tips: dualplate fixation technique for comminuted proximal humerus fractures.

    PubMed

    Choi, Sungwook; Kang, Hyunseong; Bang, Hyeongsig

    2014-08-01

    The authors report dualplate fixation technique for providing stable fixation in comminuted proximal humerus fractures. This technique has been used for proximal humerus fractures with metaphyseal comminution and provides excellent anatomical reduction and neck shaft angle (NSA). The recently locking plate is clinically more widely used due to its small size, low rigidity, high elasticity, and biomechanical properties such as fixed initial angle and rotational stability. However, in severely comminuted complex type proximal metaphyseal humerus fractures, the use of locking plate alone does not provide stable fixation, leading to complications such as varus collapse, anterior-posterior angulation, screw cutout, nonunion, malunion, and metal failure. Therefore, a more robust and enhanced fixation method, the dual plating technique using the locking compression plate (Proximal Humeral Internal Locking System and Variable Angle Locking Compression Plate) was developed. PMID:24813097

  11. Plate presetting arthroscopic reduction technique for the distal radius fractures.

    PubMed

    Abe, Yukio; Tsubone, Tetsu; Tominaga, Yasuhiro

    2008-09-01

    Wrist arthroscopy for the distal radius fractures is an effective adjunct to evaluate the reduction of intraarticular fragments and soft tissue injuries. In recent years, volar locking plate fixation has become popular, and arthroscopic procedures for distal radius fracture reduction have become problematic because vertical traction has to be both on and off during surgery. We developed a plate presetting arthroscopic reduction technique to simplify the combination of plating and arthroscopy. The fracture was reduced, and anatomic alignment was regained under an image intensifier, and then the volar locking plate was preset. Wrist arthroscopy was introduced under vertical traction, and the intraarticular condition was assessed. If dislocations of the intraarticular fragments were residual, they were reduced arthroscopically, and soft tissue injuries were treated subsequently. Finally, the traction was removed, and the plate was securely fixed. Since May 2005, the authors have used this technique in more than 50 patients. This article will review the history, indications, contraindications, technique, rehabilitation, and complications for the plate presetting arthroscopic reduction technique for distal radius fractures. PMID:18776773

  12. A Novel Approach in Security Using Gyration Slab with Watermarking Technique

    NASA Astrophysics Data System (ADS)

    Rupa, Ch.

    2015-03-01

    In this paper, a novel security approach is proposed to improve the security and robustness of the data. It uses three levels of security to protect the sensitive data. In the first level, the data is to be protected by Gyration slab encryption algorithm. Result of the first level has to be embedded into an image as original using our earlier paper concept PLSB into a second level of security. The resultant image from the second level is considered as watermark Image. In the third level, the watermark image is embedded into the original image. Here watermark image and original image are similar. The final output of the proposed security approach is a watermarked image which holds the stego image. This method provides more security and robustness than the existing approaches. The main properties of the proposed approach are Gyration slab operations and watermark image and original image are similar. These can reduce the Brute-force attack and improve the confusion and diffusion principles. The main strengths of this paper are cryptanalysis, steganalysis, watermark analysis with reports.

  13. Development of Reservoir Characterization Techniques and Production Models for Exploiting Naturally Fractured Reservoirs

    SciTech Connect

    Wiggins, Michael L.; Brown, Raymon L.; Civan, Frauk; Hughes, Richard G.

    2001-08-15

    Research continues on characterizing and modeling the behavior of naturally fractured reservoir systems. Work has progressed on developing techniques for estimating fracture properties from seismic and well log data, developing naturally fractured wellbore models, and developing a model to characterize the transfer of fluid from the matrix to the fracture system for use in the naturally fractured reservoir simulator.

  14. Fracture resistance of premolar teeth restored with different filling techniques.

    PubMed

    França, Fabiana Mantovani Gomes; Worschech, Claudia Cia; Paulillo, Luis Alexandre Maffei Sartini; Martins, Luis Roberto Marcondes; Lovadino, José Roberto

    2005-08-15

    The aim of this study is to verify the fracture resistance of premolars with large mesiocclusodistal (MOD) preparations with composite resin using different incremental techniques when subjected to an occlusal load. Forty maxillary premolar teeth were randomly divided into four groups (n=10). Class II MOD cavities were prepared in all specimens with parallel walls and no approximal boxes. The resulting isthmus width was 1/3 the distance between the cusp tips and (3/4) the height of the crown. Teeth in group I, the control group, were not restored. Specimens in group II were restored in three incremental vertical layers. Group III specimens were restored in three horizontal layers, and finally, specimens in group IV were restored in oblique layers. With exception of the placement technique, specimens in groups II, III and IV were restored using the Single Bond adhesive system and P60 composite resin following manufacturer's recommendations. A 4 mm diameter steel sphere contacted the buccal and lingual cusps of the tested teeth at a crosshead speed of 0.5 mm/min until fracture occurred. The values obtained in this study were subjected to Analysis of Variance (ANOVA) and a Tukey-Kramer test. Only group I (non-restored) obtained a minor means of fracture resistance. No significant differences among groups II, III, and IV were found. This study shows on large MOD cavities the incremental filling techniques do not influence the fracture resistance of premolar teeth restored with composite resin. PMID:16127473

  15. Scattering of the transverse magnetic modes from an abruptly ended strongly asymmetrical slab waveguide by an accelerated integral equation technique.

    PubMed

    Manenkov, A B; Latsas, G P; Tigelis, L G

    2001-12-01

    We study the problem of the scattering of the first TM guided mode from an abruptly ended strongly asymmetrical slab waveguide by an improved iteration technique, which is based on the integral equation method with "accelerating" parameters. We demonstrate that the values of these parameters are related to the variational principle, and we save approximately 1-2 iterations compared with the case in which these parameters are not employed. The tangential electric-field distribution on the terminal plane, the reflection coefficient of the first TM guided mode, and the far-field radiation pattern are computed. Furthermore, a simple technique based on the Aitken extrapolation procedure is employed for faster computation of the higher-order solutions of the reflection coefficient. Numerical results are presented for several cases of abruptly ended waveguides, including systems with variational profile, while special attention is given to the far-field radiation pattern rotation and its explanation. PMID:11760208

  16. Novel Matricing Technique for Management of Fractured Cusp Conundrum – A Clinician’s Corner

    PubMed Central

    Mittal, Priya Ramesh

    2016-01-01

    Longitudinal tooth fracture can be classified as craze lines, fractured cusp, cracked tooth, split tooth and vertical root fracture based on extent and severity of the fracture line. The most common type of longitudinal tooth fracture is fractured cusp that poses the treatment dilemma. Retention of the fractured cusp segment temporarily with matrix band followed by permanent bonded restoration and finally removal of tooth fragment during crown preparation is a novel technique. This paper throws light on a matricing and holding technique for the management of supra-crestally fractured palatal cusp of maxillary first premolar in a 29-year-old Asian male. PMID:27190970

  17. Determination of dynamic fracture toughness using a new experimental technique

    NASA Astrophysics Data System (ADS)

    Cady, Carl M.; Liu, Cheng; Lovato, Manuel L.

    2015-09-01

    In other studies dynamic fracture toughness has been measured using Charpy impact and modified Hopkinson Bar techniques. In this paper results will be shown for the measurement of fracture toughness using a new test geometry. The crack propagation velocities range from ˜0.15 mm/s to 2.5 m/s. Digital image correlation (DIC) will be the technique used to measure both the strain and the crack growth rates. The boundary of the crack is determined using the correlation coefficient generated during image analysis and with interframe timing the crack growth rate and crack opening can be determined. A comparison of static and dynamic loading experiments will be made for brittle polymeric materials. The analysis technique presented by Sammis et al. [1] is a semi-empirical solution, however, additional Linear Elastic Fracture Mechanics analysis of the strain fields generated as part of the DIC analysis allow for the more commonly used method resembling the crack tip opening displacement (CTOD) experiment. It should be noted that this technique was developed because limited amounts of material were available and crack growth rates were to fast for a standard CTOD method.

  18. Simple reproducible technique in treatment for osteopetrotic fractures.

    PubMed

    Sen, Ramesh K; Gopinathan, Nirmal Raj; Kumar, Rajesh; Saini, Uttam Chand

    2013-08-01

    Osteopetrosis is a rare skeletal condition first described by German radiologist Heinrich Albers-Schonberg. The most important technical difficulty is drilling due to hard bone in patients with osteopetrosis; recommendations have been made to use high-speed electric drill bits. But, the unavailability of this special drill bit in most of the centres makes the job more difficult. The study was conducted from 2009 to 2012; the cases are selected from Outpatients Department of Postgraduate Institute of Medical Education and Research. The patients were in the age group of 10-50 years with a mean age of 26 years. Five cases were included in the study: four patients had subtrochanteric fractures, and one had segmental fracture of the humerus. Open reduction and internal fixation was done in all the fractures using metal-cutting drill bit. The use of metal-cutting drill bit in osteopetrosis not only made our job easy but also prevented thermal necrosis of the bone to a large extent. The union rate was 100 % in our series, and there was no infection in any of our cases. In the treatment for fractures in osteopetrosis, the use of a metal-cutting drill bit along with careful attention to drilling technique can help avoid bit breakage and thermal bone injury that may produce ring sequestrum or destroy the already scant osteogenic cells. PMID:22983737

  19. The development of in situ fracture toughness evaluation techniques in hydrogen environment

    SciTech Connect

    Wang, Jy-An John; Ren, Fei; Tan, Ting; Liu, Ken C

    2014-01-01

    Fracture behavior and fracture toughness are of great interest regarding reliability of hydrogen pipelines and storage tanks, however, many conventional fracture testing techniques are difficult to be realized under the presence of hydrogen, in addition to the inherited specimen size effect. Thus it is desired to develop novel in situ fracture toughness evaluation techniques to study the fracture behavior of structural materials in hydrogen environments. In this study, a torsional fixture was developed to utilize an emerging fracture testing technique, Spiral Notch Torsion Test (SNTT). The in situ testing results indicated that the exposure to H2 significantly reduces the fracture toughness of 4340 high strength steels by up to 50 percent. Furthermore, SNTT tests conducted in air demonstrated a significant fracture toughness reduction in samples subject to simulated welding heat treatment using Gleeble, which illustrated the effect of welding on the fracture toughness of this material.

  20. Simple, minimally invasive surgical technique for treatment of type 2 fractures of the distal clavicle.

    PubMed

    Levy, Ofer

    2003-01-01

    Neer type 2 fractures of the distal clavicle have a high rate of nonunion and delayed union. A simple, minimally invasive surgical technique using suture fixation is introduced. In this series 12 patients were treated with suture fixation of this fracture with absorbable suture material, resulting in union of all fractures. There was a rapid return to function and no complications. This technique allows simple, minimally invasive fixation with good fracture healing and early return to work and sports. PMID:12610482

  1. Fast iterative, coupled-integral-equation technique for inhomogeneous profiled and periodic slabs.

    PubMed

    Magath, Thore; Serebryannikov, Andriy E

    2005-11-01

    A fast coupled-integral-equation (CIE) technique is developed to compute the plane-TE-wave scattering by a wide class of periodic 2D inhomogeneous structures with curvilinear boundaries, which includes finite-thickness relief and rod gratings made of homogeneous material as special cases. The CIEs in the spectral domain are derived from the standard volume electric field integral equation. The kernel of the CIEs is of Picard type and offers therefore the possibility of deriving recursions, which allow the computation of the convolution integrals occurring in the CIEs with linear amounts of arithmetic complexity and memory. To utilize this advantage, the CIEs are solved iteratively. We apply the biconjugate gradient stabilized method. To make the iterative solution process faster, an efficient preconditioning operator (PO) is proposed that is based on a formal analytical inversion of the CIEs. The application of the PO also takes only linear complexity and memory. Numerical studies are carried out to demonstrate the potential and flexibility of the CIE technique proposed. Though the best efficiency and accuracy are observed at either low permittivity contrast or high conductivity, the technique can be used in a wide range of variation of material parameters of the structures including when they contain components made of both dielectrics with high permittivity and typical metals. PMID:16302391

  2. Non-union coronal fracture femoral condyle, sandwich technique : A case report.

    PubMed

    Nandy, Kousik; Raman, Rajeev; Vijay, R K; Maini, Lalit

    2015-03-01

    Coronal fractures of the femoral condyle (Hoffa fracture) are rare injuries but can be managed with satisfactory outcome if properly treated. We discuss an unusual case of a young adult male presenting with 9 month old neglected Hoffa fracture with pain, stiffness and limitation of knee movement, managed with sandwich bone grafting technique.(1). PMID:26549953

  3. Non-union coronal fracture femoral condyle, sandwich technique : A case report

    PubMed Central

    Nandy, Kousik; Raman, Rajeev; Vijay, R.K.; Maini, Lalit

    2014-01-01

    Coronal fractures of the femoral condyle (Hoffa fracture) are rare injuries but can be managed with satisfactory outcome if properly treated. We discuss an unusual case of a young adult male presenting with 9 month old neglected Hoffa fracture with pain, stiffness and limitation of knee movement, managed with sandwich bone grafting technique.1 PMID:26549953

  4. Defense technique takes guesswork out of tight reservoir fracturing jobs

    SciTech Connect

    Duey, R.

    1996-05-01

    Enserch exploration and the Los Alamos National Laboratory are using a highly sensitive defense technology to map fractures in an East Texas field. A process known as nuclear test verification, using highly sophisticated detectors can actually map fractures as they occur.

  5. Fracture detection techniques in the Georgetown and Austin Chalk formations

    SciTech Connect

    Julian, P.J.

    1982-09-01

    This study relates the success of detecting and analyzing naturally fractured systems in the Austin Chalk and Georgetown Formations from log evaluations. The Austin Chalk is composed principally of calcareous unicellular algal remains called cocospheres and their disunited, gearshaped, skeletal remains called cocoliths. The Georgetown Formation is a hard, dense, and finely brittle limestone. Both formations contain matrix porosity, but are dependent on open fracture systems for economical hydrocarbon production. Hence, defining and evaluating the developed fracture systems before setting an expensive casing string is important. The Dual Induction Log and the Compensated Neutron-Formation Density Log offers an economical method of evaluating these fracture systems. Case studies in Robertson, Milam, and Burleson Counties, Texas have shown that fracture systems near the wellbore can be detected. Attempts to determine the existence of hydrocarbons in fracture systems using logs were successful in the Austin Chalk and Georgetown Formations. Full core analyses were also successful in determining the existence of these fracture systems. However, obtaining core samples on all wells as a method of determining fracture systems is not recommended due to the high cost of coring.

  6. Evolution of 3-D subduction-induced mantle flow around lateral slab edges in analogue models of free subduction analysed by stereoscopic particle image velocimetry technique

    NASA Astrophysics Data System (ADS)

    Strak, Vincent; Schellart, Wouter P.

    2014-10-01

    We present analogue models of free subduction in which we investigate the three-dimensional (3-D) subduction-induced mantle flow focusing around the slab edges. We use a stereoscopic Particle Image Velocimetry (sPIV) technique to map the 3-D mantle flow on 4 vertical cross-sections for one experiment and on 3 horizontal depth-sections for another experiment. On each section the in-plane components are mapped as well as the out-of-plane component for several experimental times. The results indicate that four types of maximum upwelling are produced by the subduction-induced mantle flow. The first two are associated with the poloidal circulation occurring in the mantle wedge and in the sub-slab domain. A third type is produced by horizontal motion and deformation of the frontal part of the slab lying on the 660 km discontinuity. The fourth type results from quasi-toroidal return flow around the lateral slab edges, which produces a maximum upwelling located slightly laterally away from the sub-slab domain and can have another maximum upwelling located laterally away from the mantle wedge. These upwellings occur during the whole subduction process. In contrast, the poloidal circulation in the mantle wedge produces a zone of upwelling that is vigorous during the free falling phase of the slab sinking but that decreases in intensity when reaching the steady-state phase. The position of the maximum upward component and horizontal components of the mantle flow velocity field has been tracked through time. Their time-evolving magnitude is well correlated to the trench retreat rate. The maximum upwelling velocity located laterally away from the subducting plate is ∼18-24% of the trench retreat rate during the steady-state subduction phase. It is observed in the mid upper mantle but upwellings are produced throughout the whole upper mantle thickness, potentially promoting decompression melting. It could thereby provide a source for intraplate volcanism, such as Mount Etna in

  7. Analysis of compressive fracture in rock using statistical techniques

    SciTech Connect

    Blair, S.C.

    1994-12-01

    Fracture of rock in compression is analyzed using a field-theory model, and the processes of crack coalescence and fracture formation and the effect of grain-scale heterogeneities on macroscopic behavior of rock are studied. The model is based on observations of fracture in laboratory compression tests, and incorporates assumptions developed using fracture mechanics analysis of rock fracture. The model represents grains as discrete sites, and uses superposition of continuum and crack-interaction stresses to create cracks at these sites. The sites are also used to introduce local heterogeneity. Clusters of cracked sites can be analyzed using percolation theory. Stress-strain curves for simulated uniaxial tests were analyzed by studying the location of cracked sites, and partitioning of strain energy for selected intervals. Results show that the model implicitly predicts both development of shear-type fracture surfaces and a strength-vs-size relation that are similar to those observed for real rocks. Results of a parameter-sensitivity analysis indicate that heterogeneity in the local stresses, attributed to the shape and loading of individual grains, has a first-order effect on strength, and that increasing local stress heterogeneity lowers compressive strength following an inverse power law. Peak strength decreased with increasing lattice size and decreasing mean site strength, and was independent of site-strength distribution. A model for rock fracture based on a nearest-neighbor algorithm for stress redistribution is also presented and used to simulate laboratory compression tests, with promising results.

  8. Hydraulic fracturing method employing a fines control technique

    SciTech Connect

    Stowe, L.R.

    1986-11-18

    A method is described for controlling fines or sand in an unconsolidated or loosely consolidated formation or reservoir penetrated by at least one wellbore where hydraulic fracturing is used in combination with control of the critical salinity rate and the critical fluid flow velocity. The method comprises: (a) placing at least one wellbore in the reservoir; (b) hydraulically fracturing the formation via the wellbore with a fracturing fluid which creates at least one fracture; (c) placing a proppant comprising a gravel pack into the fracture; (d) determining the critical salinity rate and the critical fluid flow velocity of the formation or reservoir surrounding the wellbore; (e) injecting a saline solution into the formation or reservoir at a velocity exceeding the critical fluid flow velocity and at a saline concentration sufficient to cause the fines or particles to be transferred and fixed deep wihtin the formation or reservoir without plugging the formation, fracture, or wellbore; and (f) producing a hydrocarbonaceous fluid from the formation or reservoir at a velocity such that the critical flow velocity is not exceeded deep within the formation, fracture, or wellbore.

  9. Computational techniques for the assessment of fracture repair.

    PubMed

    Anderson, Donald D; Thomas, Thaddeus P; Campos Marin, Ana; Elkins, Jacob M; Lack, William D; Lacroix, Damien

    2014-06-01

    The combination of high-resolution three-dimensional medical imaging, increased computing power, and modern computational methods provide unprecedented capabilities for assessing the repair and healing of fractured bone. Fracture healing is a natural process that restores the mechanical integrity of bone and is greatly influenced by the prevailing mechanical environment. Mechanobiological theories have been proposed to provide greater insight into the relationships between mechanics (stress and strain) and biology. Computational approaches for modelling these relationships have evolved from simple tools to analyze fracture healing at a single point in time to current models that capture complex biological events such as angiogenesis, stochasticity in cellular activities, and cell-phenotype specific activities. The predictive capacity of these models has been established using corroborating physical experiments. For clinical application, mechanobiological models accounting for patient-to-patient variability hold the potential to predict fracture healing and thereby help clinicians to customize treatment. Advanced imaging tools permit patient-specific geometries to be used in such models. Refining the models to study the strain fields within a fracture gap and adapting the models for case-specific simulation may provide more accurate examination of the relationship between strain and fracture healing in actual patients. Medical imaging systems have significantly advanced the capability for less invasive visualization of injured musculoskeletal tissues, but all too often the consideration of these rich datasets has stopped at the level of subjective observation. Computational image analysis methods have not yet been applied to study fracture healing, but two comparable challenges which have been addressed in this general area are the evaluation of fracture severity and of fracture-associated soft tissue injury. CT-based methodologies developed to assess and quantify

  10. Arthroscopic management of tibial plateau fractures: special techniques.

    PubMed

    Perez Carro, L

    1997-04-01

    Arthroscopic assessment and treatment of tibial plateau fractures has gained popularity in recent years. This article describes some maneuvers to facilitate the management of these fractures with the arthroscope. We use a 14-mm rounded curved periosteal elevator to manipulate fragments within the joint instead of using a probe. To facilitate visualization of fractures, we describe the use of loop sutures around the meniscus to retract the meniscus when there is a tear in the meniscus. We suggest the use of the arthroscope for directly viewing the interosseous space to be sure that any internal fixation devices remain outside the articular space. The use of these tactics will allow a faster, more accurate reduction with less radiation exposure in patients with displaced tibial plateau fractures. PMID:9127091

  11. The development of in situ fracture toughness evaluation techniques in hydrogen environment

    SciTech Connect

    Wang, John Jy-An; Ren, Fei; Tan, Tin; Liu, Ken

    2014-12-19

    Reliability of hydrogen pipelines and storage tanks is significantly influenced by the mechanical performance of the structural materials exposed in the hydrogen environment. Fracture behavior and fracture toughness are of specific interest since they are relevant to many catastrophic failures. However, many conventional fracture testing techniques are difficult to be realized under the presence of hydrogen. Thus it is desired to develop novel in situ techniques to study the fracture behavior of structural materials in hydrogen environments. In this study, special testing apparatus were designed to facilitate in situ fracture testing in H2. A torsional fixture was developed to utilize an emerging fracture testing technique, Spiral Notch Torsion Test (SNTT). The design concepts will be discussed. Preliminary in situ testing results indicated that the exposure to H2 significantly reduces the fracture toughness of 4340 high strength steels by up to 50 percent. Furthermore, SNTT tests conducted in air demonstrated a significant fracture toughness reduction in samples subject to simulated welding heat treatment using Gleeble, which illustrated the effect of welding on the fracture toughness of this material.

  12. The development of in situ fracture toughness evaluation techniques in hydrogen environment

    DOE PAGESBeta

    Wang, John Jy-An; Ren, Fei; Tan, Tin; Liu, Ken

    2014-12-19

    Reliability of hydrogen pipelines and storage tanks is significantly influenced by the mechanical performance of the structural materials exposed in the hydrogen environment. Fracture behavior and fracture toughness are of specific interest since they are relevant to many catastrophic failures. However, many conventional fracture testing techniques are difficult to be realized under the presence of hydrogen. Thus it is desired to develop novel in situ techniques to study the fracture behavior of structural materials in hydrogen environments. In this study, special testing apparatus were designed to facilitate in situ fracture testing in H2. A torsional fixture was developed to utilizemore » an emerging fracture testing technique, Spiral Notch Torsion Test (SNTT). The design concepts will be discussed. Preliminary in situ testing results indicated that the exposure to H2 significantly reduces the fracture toughness of 4340 high strength steels by up to 50 percent. Furthermore, SNTT tests conducted in air demonstrated a significant fracture toughness reduction in samples subject to simulated welding heat treatment using Gleeble, which illustrated the effect of welding on the fracture toughness of this material.« less

  13. Slab reformer

    DOEpatents

    Spurrier, Francis R.; DeZubay, Egon A.; Murray, Alexander P.; Vidt, Edward J.

    1984-02-07

    Slab-shaped high efficiency catalytic reformer configurations particularly useful for generation of fuels to be used in fuel cell based generation systems. A plurality of structures forming a generally rectangular peripheral envelope are spaced about one another to form annular regions, an interior annular region containing a catalytic bed and being regeneratively heated on one side by a hot comubstion gas and on the other side by the gaseous products of the reformation. An integrally mounted combustor is cooled by impingement of incoming oxidant.

  14. Slab reformer

    DOEpatents

    Spurrier, Francis R.; DeZubay, Egon A.; Murray, Alexander P.; Vidt, Edward J.

    1985-03-12

    Slab-shaped high efficiency catalytic reformer configurations particularly useful for generation of fuels to be used in fuel cell based generation systems. A plurality of structures forming a generally rectangular peripheral envelope are spaced about one another to form annular regions, an interior annular region containing a catalytic bed and being regeneratively heated on one side by a hot combustion gas and on the other side by the gaseous products of the reformation. An integrally mounted combustor is cooled by impingement of incoming oxidant.

  15. Slab reformer

    NASA Technical Reports Server (NTRS)

    Spurrier, Francis R. (Inventor); DeZubay, Egon A. (Inventor); Murray, Alexander P. (Inventor); Vidt, Edward J. (Inventor)

    1984-01-01

    Slab-shaped high efficiency catalytic reformer configurations particularly useful for generation of fuels to be used in fuel cell based generation systems. A plurality of structures forming a generally rectangular peripheral envelope are spaced about one another to form annular regions, an interior annular region containing a catalytic bed and being regeneratively heated on one side by a hot comubstion gas and on the other side by the gaseous products of the reformation. An integrally mounted combustor is cooled by impingement of incoming oxidant.

  16. Effectiveness of MIS technique as a treatment modality for open intra-articular calcaneal fractures: A prospective evaluation with matched closed fractures treated by conventional technique.

    PubMed

    Dhillon, Mandeep Singh; Gahlot, Nitesh; Satyaprakash, Sambit; Kanojia, Rajendra Kumar

    2015-09-01

    Twenty-five displaced intra-articular calcaneal fractures in 21 patients, aged 15-55 years were included in this study. Sanders' type I fractures, severe crushing or partial amputation, were excluded from the study. Patients were divided into group 1 (open fractures treated by MIS), and group 2 (closed fractures treated by ORIF). Group 1 had 16 and group 2 had 9 cases. Seven of 25 fractures (28%) developed wound related issues postoperatively. One patient (11.1%) in group 2 had wound margin necrosis, while 6 patients (37.5%) in group 1 developed pin tract and/or wound infection. At 1-year follow-up, the mean MFS for group 1 was 79 and mean MFS for group 2 was 84.4 (66.67% were good). The AOFAS score for group 1 was 77.37 and for group 2 was 86.1. The Bohlers' angle was restored in 81.16% cases in group 1 and 88.8% in group 2, while Gissane angle was restored in 68.75% of group 1 cases and 77.79% of group 2 cases. This study shows that acceptable fracture reduction can be obtained and maintained by MIS technique and it can be used as the primary definitive treatment option in open calcaneal fractures. PMID:26209469

  17. Type 2 fractures of the distal clavicle: a new surgical technique.

    PubMed

    Goldberg, J A; Bruce, W J; Sonnabend, D H; Walsh, W R

    1997-01-01

    Neer type 2 fractures of the distal clavicle have a high rate of nonunion and delayed union. In this series nine cases of coracoclavicular ligament reconstruction with Dacron graft material led to union at the fracture site. All patients had no symptoms and returned to full activity. This technique allows for stable fixation with early mobilization and return to work and sports. PMID:9285878

  18. Lower Extremity Fracture Reduction: Tips, Tricks, and Techniques So That You Leave the Operating Room Satisfied.

    PubMed

    Mir, Hassan R; Boulton, Christina L; Russell, George V; Archdeacon, Michael

    2016-01-01

    It can be challenging for surgeons to obtain proper alignment and to create stable constructs for the maintenance of many lower extremity fractures until union is achieved. Whether lower extremity fractures are treated with plates and screws or intramedullary nails, there are numerous pearls that may help surgeons deal with these difficult injuries. Various intraoperative techniques can be used for lower extremity fracture reduction and stabilization. The use of several reduction tools, tips, and tricks may facilitate the care of lower extremity fractures and, subsequently, improve patient outcomes. PMID:27049180

  19. Femoral neck fracture fixation: rigidity of five techniques compared.

    PubMed Central

    Mackechnie-Jarvis, A C

    1983-01-01

    Artificial cadaveric femoral neck fractures were internally fixed with five different devices and subjected to cyclical loading of 0-1.0 kilonewtons (approximately one body weight) whilst in an anatomical position. Displacement of the proximal fragment was detected by a transducer and charted. Bone strength was assessed by a preliminary control loading phase on the intact bone. Efficiency of each fracture fixator could then be directly compared by the relative movement in each case. Five specimens each were tested with Moore's Pins, Trifin Nail, Garden Screws and a sliding screw-plate (OEC Ltd). By the criteria of the experiment, which put a severe shearing load on the implant, none of these devices reliably bore the representative body weight. An extended barrel-plate, which supported the sliding screw almost up to the fracture line, was then made. This device, employing some of Charnley's concepts, tolerated body weight in four cases out of five. PMID:6887186

  20. Impacted and Fractured Biliary Basket: A Second Basket Rescue Technique

    PubMed Central

    Benatta, Mohammed Amine; Desjeux, Ariane; Barthet, Marc; Grimaud, Jean Charles; Gasmi, Mohamed

    2016-01-01

    A 59-year-old woman was treated with ERCP, ES, and biliary plastic stent, for large and multiple common bile duct stones. During a second ERCP basket extraction was impacted with a round entrapped stone. The basket handle was cut off; a metal sheath of extraendoscopic lithotriptor was advanced over the basket. The mechanical lithotripsy was complicated with basket traction wires fracturing, without breakage of the stone. A rescue standard basket was pushed until it caught the basket/stone complex. Using this method disengagement of the whole fractured basket/stone complex was achieved without need of surgery. It is the third case reported in the English literature. PMID:27293442

  1. An innovative technique for evaluating fracture toughness of graphite materials

    NASA Astrophysics Data System (ADS)

    Wang, Jy-An John; Liu, Ken C.

    2008-10-01

    Spiral notch torsion fracture toughness test (SNTT) was developed recently to measure the intrinsic fracture toughness ( KIC) of structural materials. The SNTT system operates by applying pure torsion to uniform cylindrical specimens with a notch line that spirals around the specimen at a 45° pitch. The KIC values are obtained with the aid of a three-dimensional finite-element computer code, TOR3D-KIC. The SNTT method is uniquely suitable for testing a wide variety of materials used extensively in pressure vessel and piping structural components and weldments, including others such as ceramics, their composites, and concrete.

  2. Impacted and Fractured Biliary Basket: A Second Basket Rescue Technique.

    PubMed

    Benatta, Mohammed Amine; Desjeux, Ariane; Barthet, Marc; Grimaud, Jean Charles; Gasmi, Mohamed

    2016-01-01

    A 59-year-old woman was treated with ERCP, ES, and biliary plastic stent, for large and multiple common bile duct stones. During a second ERCP basket extraction was impacted with a round entrapped stone. The basket handle was cut off; a metal sheath of extraendoscopic lithotriptor was advanced over the basket. The mechanical lithotripsy was complicated with basket traction wires fracturing, without breakage of the stone. A rescue standard basket was pushed until it caught the basket/stone complex. Using this method disengagement of the whole fractured basket/stone complex was achieved without need of surgery. It is the third case reported in the English literature. PMID:27293442

  3. DEVELOPMENT OF RESERVOIR CHARACTERIZATION TECHNIQUES AND PRODUCTION MODELS FOR EXPLOITING NATURALLY FRACTURED RESERVOIRS

    SciTech Connect

    Michael L. Wiggins; Raymon L. Brown; Faruk Civan; Richard G. Hughes

    2002-12-31

    For many years, geoscientists and engineers have undertaken research to characterize naturally fractured reservoirs. Geoscientists have focused on understanding the process of fracturing and the subsequent measurement and description of fracture characteristics. Engineers have concentrated on the fluid flow behavior in the fracture-porous media system and the development of models to predict the hydrocarbon production from these complex systems. This research attempts to integrate these two complementary views to develop a quantitative reservoir characterization methodology and flow performance model for naturally fractured reservoirs. The research has focused on estimating naturally fractured reservoir properties from seismic data, predicting fracture characteristics from well logs, and developing a naturally fractured reservoir simulator. It is important to develop techniques that can be applied to estimate the important parameters in predicting the performance of naturally fractured reservoirs. This project proposes a method to relate seismic properties to the elastic compliance and permeability of the reservoir based upon a sugar cube model. In addition, methods are presented to use conventional well logs to estimate localized fracture information for reservoir characterization purposes. The ability to estimate fracture information from conventional well logs is very important in older wells where data are often limited. Finally, a desktop naturally fractured reservoir simulator has been developed for the purpose of predicting the performance of these complex reservoirs. The simulator incorporates vertical and horizontal wellbore models, methods to handle matrix to fracture fluid transfer, and fracture permeability tensors. This research project has developed methods to characterize and study the performance of naturally fractured reservoirs that integrate geoscience and engineering data. This is an important step in developing exploitation strategies for

  4. Unilateral lag-screw technique for an isolated anterior 1/4 atlas fracture

    PubMed Central

    Keskil, Semih; Göksel, Murat; Yüksel, Ulaş

    2016-01-01

    Study Design: Fractures of the atlas are classified based on the fracture location and associated ligamentous injury. Among patients with atlas fractures treated using external immobilization, nonunion of the fracture could be seen. Objective: Ideally, treatment strategy for an unstable atlas fracture would involve limited fixation to maintain the fracture fragments in a reduced position without restricting the range of motion (ROM) of the atlantoaxial and atlantooccipital joints. Summary of Background Data: Such a result can be established using either transoral limited internal fixation or limited posterior lateral mass fixation. However, due to high infection risk and technical difficulty, posterior approaches are preferred but none of these techniques can fully address anterior 1/4 atlas fractures such as in this case. Materials and Methods: A novel open and direct technique in which a unilateral lag screw was placed to reduce and stabilize a progressively widening isolated right-sided anterior 1/4 single fracture of C1 that was initially treated with a rigid cervical collar is described. Results: Radiological studies made after the surgery showed no implant failure, good cervical alignment, and good reduction with fusion of C1. Conclusions: It is suggested that isolated C1 fractures can be surgically reduced and immobilized using a lateral compression screw to allow union and maintain both C1-0 and C1-2 motions, and in our knowledge this is the first description of the use of a lag screw to achieve reduction of distracted anterior 1/4 fracture fragments of the C1 from a posterior approach. This technique has the potential to become a valuable adjunct to the surgeon's armamentarium, in our opinion, only for fractures with distracted or comminuted fragments whose alignment would not be expected to significantly change with classical lateral mass screw reduction. PMID:27041886

  5. [Periprosthetic humeral fractures: Strategies and techniques of revision arthroplasty].

    PubMed

    Kirchhoff, C; Beirer, M; Brunner, U

    2016-04-01

    The primary aims when performing revision arthroplasty of periprosthetic humeral fractures (PHF) are preservation of bone stock, achieving fracture healing and preserving a stable prosthesis with the focus on regaining the preoperative shoulder-arm function. The indications for revision arthroplasty are given in PHF in combination with loosening of the stem. In addition, further factors must be independently clarified in the case of an anatomical arthroplasty. In this context secondary glenoid erosion as well as rotator cuff insufficiency are potential factors for an extended revision procedure. For the performance of revision surgery modular revision sets including long stems, revision glenoid and metaglene components as well as plate and cerclage systems are obligatory besides the explantation instrumentation. Despite a loosened prosthesis, a transhumeral removal of the stem along with a subpectoral fenestration are often required. Length as well as bracing of revision stems need to bridge the fracture by at least twice the humeral diameter. Moreover, in many cases a combined procedure using an additional distal open reduction and internal fixation (ORIF) plus cable cerclages as well as biological augmentation might be needed. Assuming an adequate preparation, the experienced surgeon is able to achieve a high fracture union rate along with an acceptable or even good shoulder function and to avoid further complications. PMID:26992713

  6. Effect of Different Instrumentation Techniques on Vertical Root Fracture Resistance of Endodontically Treated Teeth

    PubMed Central

    Tavanafar, Saeid; Karimpour, Azadeh; Karimpour, Hamideh; Mohammed Saleh, Abdulrahman; Hamed Saeed, Musab

    2015-01-01

    Statement of the Problem Vertical root fractures are catastrophic events that often result in tooth extraction. Many contributing factor are associated with increasing incidence of vertical root fracture. Root canal preparation is one of the predisposing factors which can increase the root susceptibility to vertical fracture. Purpose The aim of this study was to compare the effects of three different instrumentation techniques on vertical root fracture resistance of endodontically treated teeth. Materials and Methods In this study, 120 freshly extracted mandibular premolar teeth of similar dimensions were decoronated and randomly divided into control (n=30), nickel-titanium hand K-file (HF, n=30), BioRaCe rotary file (BR, n=30), and WaveOne reciprocating single-file (WO, n=30) groups. After cleaning and shaping the root canals, AH26 was used as canal sealer, and obturation was completed using the continuous wave technique. The root canals were embedded vertically in standardised autopolymerising acrylic resin blocks, and subjected to a vertical load to cause vertical root fracture. The forces required to induce fractures were measured using a universal testing machine. ANOVA and Tukey’s post-hoc test were used to analyse the data. Results All experimental groups showed statistically significant reductions in fracture resistance as compared with the control group. There was a statistically significant difference between the HF and BR groups. The WO group did not differ significantly from the HF group or the BR group. Conclusion All three instrumentation techniques caused weakening of the structure of the roots, and rendered them susceptible to fracture under lesser load than unprepared roots. The fracture resistance of roots prepared with the single-file reciprocating technique was similar to that of those prepared with NiTi hand and rotary instrumentation techniques. PMID:26106635

  7. Diverting technique to stage fracturing treatments in horizontal wellbores

    SciTech Connect

    Jennings, A.R. Jr.

    1990-08-28

    This patent describes a method for fracturing a formation containing a horizontal wellbore. It comprises perforating a horizontal wellbore at a desired first interval at a distance farthest from an angle of deviation from vertical of the wellbore thereby causing the wellbore to be in fluid communication with the formation; fracturing hydraulically the formation at the first interval; injecting a solidifiable gel containing a gel breaker into the wellbore witch enters the first interval; displacing with a wiper plug the solidifiable gel so as to force the solidifiable gel into the first interval and contain the gel in the wellbore in an area adjacent to the perforations; allowing the solidifiable gel to remain in the formation and in the wellbore for a time sufficient to form a solid gel in the first interval and a solid gel plug in the wellbore which precludes fluid entry into the wellbore adjacent the first interval; while the solid gel plug remains in the wellbore, perforating another section of the wellbore so as to cause fluid communication between a second interval of the formation and the wellbore; and fracturing hydraulically the formation through perforations so as to cause a second interval to be in fluid communication with the wellbore.

  8. 3D fast spin echo with out-of-slab cancellation: a technique for high-resolution structural imaging of trabecular bone at 7 Tesla.

    PubMed

    Magland, Jeremy F; Rajapakse, Chamith S; Wright, Alexander C; Acciavatti, Raymond; Wehrli, Felix W

    2010-03-01

    Spin-echo-based pulse sequences are desirable for the application of high-resolution imaging of trabecular bone but tend to involve high-power deposition. Increased availability of ultrahigh field scanners has opened new possibilities for imaging with increased signal-to-noise ratio (SNR) efficiency, but many pulse sequences that are standard at 1.5 and 3 T exceed specific absorption rate limits at 7 T. A modified, reduced specific absorption rate, three-dimensional, fast spin-echo pulse sequence optimized specifically for in vivo trabecular bone imaging at 7 T is introduced. The sequence involves a slab-selective excitation pulse, low-power nonselective refocusing pulses, and phase cycling to cancel undesired out-of-slab signal. In vivo images of the distal tibia were acquired using the technique at 1.5, 3, and 7 T field strengths, and SNR was found to increase at least linearly using receive coils of identical geometry. Signal dependence on the choice of refocusing flip angles in the echo train was analyzed experimentally and theoretically by combining the signal from hundreds of coherence pathways, and it is shown that a significant specific absorption rate reduction can be achieved with negligible SNR loss. PMID:20187181

  9. Locking plate fixation of distal femoral fractures is a challenging technique: a retrospective review

    PubMed Central

    Toro, Giuseppe; Calabrò, Giampiero; Toro, Antonio; de Sire, Alessandro; Iolascon, Giovanni

    2015-01-01

    Summary Distal femoral fractures have typically a bimodal occurrence: in young people due to a high-energy trauma and in older people related to a low-energy trauma. These fractures are associated to a very high morbidity and mortality in elderly. Distal femoral fractures might be treated with plates, intramedullary nails, external fixations, and prosthesis. However, difficulties in fracture healing and the rate of complications are important clinical issues. The purpose of this retrospective review was to present our experience in treatment of distal femoral fracture in a sample of older people in order to evaluate the technical pitfalls and strategies used to face up the fractures unsuccessfully treated with locking plates. We included people aged more than 65 years, with a diagnosis of distal femoral fracture, treated with locking plates. We considered ‘unsuccessfully treated’ the cases with healing problems or hardware failures. Of the 12 patients (9 females and 3 males; mean aged 68.75 ± 3.31 years) included, we observed 3 ‘unsuccessfully cases’, 2 due to nonunions and 1 due to an early hardware failure, all treated using a condylar blade plate with a bone graft. One patient obtained a complete fracture healing after 1 year and in the other cases there was a nonunion. We observed as most common technical pitfalls: inadequate plate lengthening, fracture bridging, and number of locking screws. The use of locking plates is an emerging technique to treat these fractures but it seems more challenging than expected. In literature there is a lack of evidences about the surgical management of distal femoral fractures that is still an important challenge for the orthopaedic surgeon that has to be able to use all the fixation devices available. PMID:27134634

  10. Two-Tension-Band Technique in Revision Surgery for Fixation Failure of Patellar Fractures.

    PubMed

    Xue, Zichao; Qin, Hui; Ding, Haoliang; Xu, Haitao; An, Zhiquan

    2016-01-01

    BACKGROUND Failed patellar fracture fixation is rare, and is usually attributed to technical errors. There are no specific details available on how to address this problem. We present our two-tension-band technique for fixing patellar fractures. MATERIAL AND METHODS Between March 2010 and March 2013, 4 men and 2 women with failed fixation patellar fractures were treated in our department. Their average age was 34 years (range 23-49 years). The initial fracture type was C1 in 3, C2 in 1, and C3 in 2, according to the AO classification. The initial fracture patterns included 3 transverse and 3 comminuted fractures. There were no open fractures. All patients underwent internal fixation with a modified anterior tension band (MATB) supplemented with cerclage wiring. All failures were caused by tension bands sliding past the tip of the Kirschner wires. The mean time between the primary and revision operations was 16.2 months (range 2-63 months). We revised the fractures by two-separate-tension-band technique. RESULTS The mean follow-up was 52 months (range 31-67 months). All patients healed radiographically without complications at an average of 14.7 weeks (range 8-20 weeks). The Bostman knee score was excellent in 3 and good in 3. All patients regained full extension and the mean range of flexion was 147.5° (135-155°). CONCLUSIONS Use of this two-tension-band technique can avoid technical errors and provide more secure fixation. We recommend it for both primary and revision surgery of patellar fractures. PMID:27485104

  11. Two-Tension-Band Technique in Revision Surgery for Fixation Failure of Patellar Fractures

    PubMed Central

    Xue, Zichao; Qin, Hui; Ding, Haoliang; Xu, Haitao; An, Zhiquan

    2016-01-01

    Background Failed patellar fracture fixation is rare, and is usually attributed to technical errors. There are no specific details available on how to address this problem. We present our two-tension-band technique for fixing patellar fractures. Material/Methods Between March 2010 and March 2013, 4 men and 2 women with failed fixation patellar fractures were treated in our department. Their average age was 34 years (range 23–49 years). The initial fracture type was C1 in 3, C2 in 1, and C3 in 2, according to the AO classification. The initial fracture patterns included 3 transverse and 3 comminuted fractures. There were no open fractures. All patients underwent internal fixation with a modified anterior tension band (MATB) supplemented with cerclage wiring. All failures were caused by tension bands sliding past the tip of the Kirschner wires. The mean time between the primary and revision operations was 16.2 months (range 2–63 months). We revised the fractures by two-separate-tension-band technique. Results The mean follow-up was 52 months (range 31–67 months). All patients healed radiographically without complications at an average of 14.7 weeks (range 8–20 weeks). The Bostman knee score was excellent in 3 and good in 3. All patients regained full extension and the mean range of flexion was 147.5° (135–155°). Conclusions Use of this two-tension-band technique can avoid technical errors and provide more secure fixation. We recommend it for both primary and revision surgery of patellar fractures. PMID:27485104

  12. Assessment of fracture-sampling techniques for laboratory tests on core

    USGS Publications Warehouse

    Severson, G.R.; Boernge, J.M.

    1991-01-01

    As part of the site characterization work to be done at Yucca Mountain in Nye County, Nevada, a candidate site for the first mined-geologic repository for high-level nuclear waste, laboratory tests are proposed to evaluate fluid flow in single fractures. Laboratory and onsite tests were conducted to develop methods for collecting rock-core samples containing single fractures for the subsequent laboratory tests. Techniques for collecting rock cores with axial (parallel to the core axis) and radial (perpendicular to the core axis) fractures are discussed.

  13. [Periprosthetic humeral fractures: Strategies and techniques for osteosynthesis].

    PubMed

    Kirchhoff, C; Brunner, U; Biberthaler, P

    2016-04-01

    The prevalence of periprosthetic humeral fractures (PHF) is currently low and accounts for 0.6-2.4%. Due to an increase in the rate of primary implantations a quantitative increase of PHF is to be expected in the near future. The majority of PHF occur intraoperatively during implantation with an increased risk for cementless stems and when performing total arthroplasty. Additional risk factors are in particular female gender and the severity of comorbidities. In contrast, postoperative PHF mostly due to low-energy falls, have a prevalence between 0.6% and 0.9% and are significantly less common. The prognosis and functional outcome following revision by open reduction internal fixation (ORIF) essentially depend on a thorough assessment of the indications for revision surgery, the operative treatment and the pretraumatic functional condition of the affected shoulder. In the armamentarium of periprosthetic ORIF of the humerus cerclage systems and locking implants as well as a combination of both play a central role. In comminuted fractures with extensive defect zones, severely thinned cortex or extensive osteolysis a biological augmentation of the ORIF should be considered. In this context when the indications are correctly interpreted, especially in the case of a stable anchored stem, various groups have reported that a high bony union rate can be achieved. As the treatment of PHF is complex it should be performed in dedicated centers in order to adequately address potential comorbidities, especially in the elderly population. PMID:27008215

  14. Rigid Intramedullary Nailing of Femoral Shaft Fractures for Patients Age 12 and Younger: Indications and Technique.

    PubMed

    Martus, Jeffrey E

    2016-06-01

    Femoral shaft fractures are common injuries in the pediatric and adolescent age groups. Rigid intramedullary nailing is an excellent treatment option for older children and adolescents, particularly for length-unstable fractures and larger patients (>49 kg). Appropriate indications, contraindications, and preoperative assessment are described. The rigid nailing surgical technique is detailed including positioning, operative steps, pearls, and pitfalls. Complications and the reported outcomes of lateral trochanteric entry nailing are reviewed from the published series. PMID:27100036

  15. Repair of a fractured implant overdenture gold bar: A clinical and laboratory technique report

    PubMed Central

    Vohra, Fahim; Al Fawaz, Amani

    2013-01-01

    This clinical report explains a convenient, efficient, yet effective alternative for management of fractured substructure cast bars for implant-retained overdentures. The technique allows the fracture to be repaired at low cost and short time without remaking the substructure and the denture and further allowing the patient to keep their denture. The report sketches the clinical and laboratory procedures involved in the repair. PMID:24926222

  16. Long-term results following polydioxanone sling fixation technique in unstable lateral clavicle fracture.

    PubMed

    Teoh, Kar H; Jones, Sian A; Robinson, Juan D; Pritchard, Mark G

    2016-04-01

    Neer type II (Edinburgh type 3B) fractures of the lateral clavicle are unstable fractures. The optimal management of these fractures remains controversial with many surgical techniques described in the literature. Our study reports the long-term results of a modified suture (1.5-mm polydioxanone cord) and sling technique for these fractures to avoid complications associated with current techniques in the literature. Over a 5-year period, 23 patients who were (12 males, 11 females; 14 left, 9 right) with a mean age of 42 years were treated with this technique. At last follow-up, the mean Oxford score was 45.1 (range 36-48); the mean SPADI score was 7.4 (range 0-32.3); and the mean Constant score was 91.5 (range 71-100). There were one non-union and no malunion. All patients in our series, except one, returned to their pre-injury activity level. This modified suture fixation technique is safe, technically simple to perform and cheap. It achieves excellent rates of fracture union without the complications associated with other fixation methods in the literature. PMID:26794324

  17. Progress on slab lasers

    NASA Astrophysics Data System (ADS)

    Albrecht, G. F.; Eggleston, J. M.; Petr, R. A.

    1986-01-01

    After a brief overview of slab geometry work published to date, zig-zag optical path slab laser development toward a 100-Hz slab YAG system ('Centurion') and a 10-Hz dual slab glass system ('Gemini') is described. Some of the major diagnostic work performed and in the process is also described to illustrate the major mechanisms responsible for beam distortion observed in these types of slab lasers.

  18. Subbrow Approach as a Minimally Invasive Reduction Technique in the Management of Frontal Sinus Fractures

    PubMed Central

    Lee, Yewon; Shin, Dong Hyeok; Uhm, Ki Il; Kim, Soon Heum; Kim, Cheol Keun; Jo, Dong In

    2014-01-01

    Background Frontal sinus fractures, particularly anterior sinus fractures, are relatively common facial fractures. Many agree on the general principles of frontal fracture management; however, the optimal methods of reduction are still controversial. In this article, we suggest a simple reduction method using a subbrow incision as a treatment for isolated anterior sinus fractures. Methods Between March 2011 and March 2014, 13 patients with isolated frontal sinus fractures were treated by open reduction and internal fixation through a subbrow incision. The subbrow incision line was designed to be precisely at the lower margin of the brow in order to obtain an inconspicuous scar. A periosteal incision was made at 3 mm above the superior orbital rim. The fracture site of the frontal bone was reduced, and bone fixation was performed using an absorbable plate and screws. Results Contour deformities were completely restored in all patients, and all patients were satisfied with the results. Scars were barely visible in the long-term follow-up. No complications related to the procedure, such as infection, uncontrolled sinus bleeding, hematoma, paresthesia, mucocele, or posterior wall and brain injury were observed. Conclusions The subbrow approach allowed for an accurate reduction and internal fixation of the fractures in the anterior table of the frontal sinus by providing a direct visualization of the fracture. Considering the surgical success of the reduction and the rigid fixation, patient satisfaction, and aesthetic problems, this transcutaneous approach through a subbrow incision is concluded to be superior to the other reduction techniques used in the case of an anterior table frontal sinus fracture. PMID:25396180

  19. Bicondylar tibial plateau fractures managed with the Sheffield Hybrid Fixator. Biomechanical study and operative technique.

    PubMed

    Ali, A M; Yang, L; Hashmi, M; Saleh, M

    2001-12-01

    The two main challenges in the management of bicondylar tibial plateau fractures are: Firstly, the compromised skin and soft tissue envelope which invite a high rate of complications following attempted open reduction and dual plating. Secondly, poor bone quality and comminuted fracture patterns, which create difficulty in achieving stable fixation. Although dual plating is considered to be the best mechanical method of stabilizing these complex fractures, there remains concern regarding the high rate of complications associated with extensive soft tissue dissection, required for the insertion of these plates in an already compromised knee. The Sheffield Hybrid fixator (SHF) technique offers a solution to the two main problems of these difficult fractures by minimizing soft tissue dissection, since bone fragments are reduced and fixed percutaneously, and providing superior cancellous bone purchase with beam loading stabilization for comminuted fractures. Our biomechanical testing showed the SHF with four tensioned wires to be as strong as dual plating and able to provide adequate mechanical stability in the fixation of bicondylar tibial plateau fractures. This was confirmed clinically by a prospective review of the use of the SHF at our centre, for managing complex and high-energy tibial plateau fractures with a good final outcome and no cases of deep infection or septic arthritis. PMID:11812481

  20. Closed-Loop Double Endobutton Technique for Repair of Unstable Distal Clavicle Fractures

    PubMed Central

    Struhl, Steven; Wolfson, Theodore S.

    2016-01-01

    Background: Displaced fractures of the distal clavicle are inherently unstable and lead to nonunion in a high percentage of cases. The optimal surgical management remains controversial. Hypothesis: Indirect osteosynthesis with a closed-loop double endobutton construct would result in reliable fracture union and obviate the need for additional surgery. Study Design: Case series; Level of evidence, 4. Methods: Eight patients with an acute unstable Neer type IIB distal clavicle fracture were treated with a closed-loop double endobutton implant. Mean follow-up averaged 3.4 years (range, 1-9 years). Two patients were lost to follow-up. The remaining 6 patients underwent a detailed functional and radiologic evaluation. Results: Definitive fracture healing was achieved in all patients. There were no complications, and no patients required additional surgery related to the index procedure. The mean Constant score was 97 at final follow-up. Conclusion: The closed-loop double endobutton technique was reliable and effective in achieving fracture union in all patients with unstable Neer type IIB fractures of the distal clavicle. This technique obviates the need for late hardware removal that is often necessary when direct osteosynthesis is used and avoids potential complications associated with coracoclavicular cerclage constructs that require knot fixation. PMID:27504466

  1. Fractures

    PubMed Central

    Hall, Michael C.

    1963-01-01

    Recent studies on the epidemiology and repair of fractures are reviewed. The type and severity of the fracture bears a relation to the age, sex and occupation of the patient. Bone tissue after fracture shows a process of inflammation and repair common to all members of the connective tissue family, but it repairs with specific tissue. Cartilage forms when the oxygen supply is outgrown. After a fracture, the vascular bed enlarges. The major blood supply to healing tissue is from medullary vessels and destruction of them will cause necrosis of the inner two-thirds of the cortex. Callus rapidly mineralizes, but full mineralization is achieved slowly; increased mineral metabolism lasts several years after fracture. PMID:13952119

  2. Biomechanical comparison of four mandibular angle fracture fixation techniques.

    PubMed

    Muñante-Cardenas, Jose Luis; Passeri, Luis Augusto

    2015-06-01

    The aim of this study was to make a comparison of the biomechanical behavior of four different internal fixation systems for mandibular angle fractures. A total of 40 polyurethane mandible replicas were employed with different fixation methods: group 1SP, one 2.0-mm four-hole miniplate; group 2PPL, two 2.0-mm four-hole parallel miniplates; group 3DP, one 3D 2.0-mm four-hole miniplate; and group 3DPP, one 3D 2.0-mm eight-hole miniplate. Each group was subjected to incisal or homolateral molar region loading. The load resistance values were measured at load application causing tip displacement of 1, 3, and 5 mm, and at the time at which the system achieves its maximum strength (MS). Means and standard deviations were compared among groups using analysis of variance and the Tukey test. Group 2PPL showed higher strength for all the displacements. For incisal loading, no statistically significant differences were found between groups 1SP, 3DP, and 3DPP. For molar loading, group 1SP and 3DPP showed statistically significant differences. For MS testing, group 1SP and 2PPL showed statistically significant differences in incisal loading; group 1SP and 3DP showed no statistically significant differences; and group 3DPP showed lower values of strength. Two parallel miniplates provide the most favorable mechanical behavior under the conditions tested. PMID:26000083

  3. Biomechanical Comparison of Four Mandibular Angle Fracture Fixation Techniques

    PubMed Central

    Muñante-Cardenas, Jose Luis; Passeri, Luis Augusto

    2014-01-01

    The aim of this study was to make a comparison of the biomechanical behavior of four different internal fixation systems for mandibular angle fractures. A total of 40 polyurethane mandible replicas were employed with different fixation methods: group 1SP, one 2.0-mm four-hole miniplate; group 2PPL, two 2.0-mm four-hole parallel miniplates; group 3DP, one 3D 2.0-mm four-hole miniplate; and group 3DPP, one 3D 2.0-mm eight-hole miniplate. Each group was subjected to incisal or homolateral molar region loading. The load resistance values were measured at load application causing tip displacement of 1, 3, and 5 mm, and at the time at which the system achieves its maximum strength (MS). Means and standard deviations were compared among groups using analysis of variance and the Tukey test. Group 2PPL showed higher strength for all the displacements. For incisal loading, no statistically significant differences were found between groups 1SP, 3DP, and 3DPP. For molar loading, group 1SP and 3DPP showed statistically significant differences. For MS testing, group 1SP and 2PPL showed statistically significant differences in incisal loading; group 1SP and 3DP showed no statistically significant differences; and group 3DPP showed lower values of strength. Two parallel miniplates provide the most favorable mechanical behavior under the conditions tested. PMID:26000083

  4. Surgical Technique of Anterolateral Approach for Tibial Plateau Fracture.

    PubMed

    Wang, Peng-cheng; Ren, Dong; Zhou, Bing

    2015-11-01

    A 66-year-old woman had sustained crush injury 3 hours prior to her presentation to our hospital. The diagnosis was defined as lateral tibial plateau fracture of the right knee (Schatzker III). Supine position was set up and a pad was put under the affected hip. After sterilization of the surgical field the sterilized sheets were placed beneath the leg in order to be higher than the other side. A rolled sheet was put under the knee joint so that the knee joint was flexed around 30° to 40°. After the surgical field was draped the skin was incised. Iliotibial band was incised by blade (not by electrotomy) and sharp dissection was performed in the Gerdy's tubercle. Capsulotomy was made by cutting the tibial meniscal ligament. Then the meniscus was tagged superiorly and the articular surface was clearly visualized. A window was made in the lateral cortex beneath the plateau, so the impacted fragment was elevated through the window. The metaphyseal void was filled by bone allograft. The placement of the raft-screw plate must be ensured that the raft screws passing the plate could purchase the subchondral bone. After perfect placement of the plate was defined, the femoral distractor was removed and the knee joint was relaxed. It was ensured that the alignment of the lower leg was normal, and then the other screws were inserted. Following placing drainage in the wound the iliotibial band was closed and the subcutaneous soft tissue and skin were closed in layer. PMID:26791810

  5. Effect of different veneering techniques on the fracture strength of metal and zirconia frameworks

    PubMed Central

    Turk, Ayse Gozde; Ulusoy, Mubin; Yuce, Mert

    2015-01-01

    PURPOSE To determine whether the fracture strengths and failure types differed between metal and zirconia frameworks veneered with pressable or layering ceramics. MATERIALS AND METHODS A phantom molar tooth was prepared and duplicated in 40 cobalt-chromium abutments. Twenty metal (IPS d.SIGN 15, Ivoclar, Vivadent, Schaan, Liechtenstein) and 20 zirconia (IPS e.max ZirCAD, Ivoclar) frameworks were fabricated on the abutments. Each framework group was randomly divided into 2 subgroups according to the veneering material: pressable and layering ceramics (n=10). Forty molar crowns were fabricated, cemented onto the corresponding abutments and then thermocycled (5-55℃, 10,000 cycles). A load was applied in a universal testing machine until a fracture occurred on the crowns. In addition, failure types were examined using a stereomicroscope. Fracture load data were analyzed using one-way ANOVA and Tukey HSD post-hoc tests at a significance level of 0.05. RESULTS The highest strength value was seen in metal-pressable (MP) group, whereas zirconia-pressable (ZP) group exhibited the lowest one. Moreover, group MP showed significantly higher fracture loads than group ZP (P=.015) and zirconia-layering (ZL) (P=.038) group. No significant difference in fracture strength was detected between groups MP and ML, and groups ZP and ZL (P>.05). Predominant fracture types were cohesive for metal groups and adhesive for zirconia groups. CONCLUSION Fracture strength of a restoration with a metal or a zirconia framework was independent of the veneering techniques. However, the pressing technique over metal frameworks resisted significantly higher fracture loads than zirconia frameworks. PMID:26816575

  6. Intramedullary nailing of the tibia without a fracture table: the transfixion pin distractor technique.

    PubMed

    Moed, B R; Watson, J T

    1994-01-01

    A series of 44 fractures of the tibia requiring operative stabilization were treated using an intraoperative external transfixion pin frame to correct angular deformity and maintain length in preparation for intramedullary (IM) nailing, eliminating the need for a fracture table. The technique requires a radiolucent operating room table; the injured extremity is draped free. A transfixion pin is inserted in the os calcis. Rotational deformity is manually corrected. Using fluoroscopic control, a second transfixion pin is inserted at a location just distal and parallel to the proximal tibial articular surface, paralleling the horizontal plane of the first pin. The transfixion pins are connected with carbon fiber rods, creating a rectangular frame. Manual fracture reduction is followed by "fine tuning" with compressor/distractor clamps as needed. Alternatively, for added reduction force, the carbon fiber rod on the concave side of the angular deformity may be replaced with the AO/ASIF universal distractor. IM nailing is then performed in the usual fashion. In this series, an acceptable reduction was obtained in all cases. This technique shortens setup time, provides complete access to the distal part of the tibia, and allows free manipulation of the limb, thereby facilitating nail insertion and placement of distal locking screws. Use of medial and lateral bars prevents the angular deformity often created or exacerbated with the use of the universal distractor alone. This technique is recommended for IM nailing of all fractures of the tibia that would otherwise require use of the fracture table or universal distractor. PMID:8027887

  7. Reduction and fixation of the avulsion fracture of the tibial eminence using mini-open technique.

    PubMed

    Lu, Xiong-Wei; Hu, Xiao-Peng; Jin, Chen; Zhu, Tong; Ding, Yong; Dai, Li-Yang

    2010-11-01

    The purpose of this prospective study is to present and evaluate a new technique using suture anchors for the treatment of the avulsion fractures of the tibial eminence. Twenty-three consecutive patients with the displaced avulsion fracture of the tibial attachment of anterior cruciate ligament were treated using mini-open technique with suture anchors between 2005 and 2008. According to the classification of Meyers and McKeever, there were 5 type II, 13 type III, and 5 type IV fractures. The median follow-up period was 18 months (range, 12-32 months). The patient assessment included Lysholm score, Tegner score, IKDC score, and radiographic evaluation. The median Lysholm score improved from 32 (range, 28-48) preoperatively to 98 (range, 85-100) postoperatively. The median preoperative Tegner score was 3 (range, 2-5), and the median postoperative Tegner score was 7 (range, 5-9). The global IKDC objective score was normal (A) in 21 knees and nearly normal (B) in 2 knees. At final follow-up, the Lachman test and anterior drawer test were negative. The results showed that mini-open reduction and fixation of avulsion fracture of the tibial eminence with suture anchors have achieved satisfactory results. We suggest the use of this technique for treating avulsion fractures of the tibial eminence. PMID:20127313

  8. Minifragment screw fixation of oblique metacarpal fractures: a biomechanical analysis of screw types and techniques.

    PubMed

    Liporace, Frank A; Kinchelow, Tosca; Gupta, Salil; Kubiak, Erik N; McDonnell, Matthew

    2008-12-01

    The lag screw technique has historically been a successful and accepted way to treat oblique metacarpal fractures. However, it does take additional time and involve multiple steps that can increase the risk of fracture propagation or comminution in the small hand bones of the hand. An alternate fixation technique uses bicortical interfragmentary screws. Other studies support the clinical effectiveness and ease of this technique. The purpose of this study is to biomechanically assess the strength of the bicortical interfragmentary screw versus that of the traditional lag screw. Using 48 cadaver metacarpals, oblique osteotomies were created and stabilized using one of four methods: 1.5 mm bicortical interfragmentary (IF) screw, 1.5 mm lag technique screw, 2.0 mm bicortical IF screw, or 2.0 mm lag technique screw. Biomechanical testing was performed to measure post cyclic displacement and load to failure. Data was analyzed using one-way analysis of variance (ANOVA). There was no significant difference among the fixation techniques with regard to both displacement and ultimate failure strength. There was a slight trend for a higher load to failure with the 2.0 mm IF screw and 2.0 mm lag screw compared to the 1.5 mm IF and 1.5 mm lag screws, but this was not significant. Our results support previously established clinical data that bicortical interfragmentary screw fixation is an effective treatment option for oblique metacarpal fractures. This technique has clinical importance because it is an option to appropriately stabilize the often small and difficult to control fracture fragments encountered in metacarpal fractures. PMID:18780019

  9. Numerical simulation of dynamic fracture and failure in solids

    SciTech Connect

    Chen, E.P.

    1994-05-01

    Numerical simulation of dynamic fracture and failure processes in solid continua using Lagrangian finite element techniques is the subject of discussion in this investigation. The specific configurations in this study include penetration of steel projectiles into aluminum blocks and concrete slabs. The failure mode in the aluminum block is excessive deformation while the concrete slab fails by hole growth, spallation, and scabbing. The transient dynamic finite element code LS-DYNA2D was used for the numerical analysis. The erosion capability in LS-DYNA2D was exercised to carry out the fracture and failure simulations. Calculated results were compared to the experimental data. Good correlations were obtained.

  10. Combination fracturing/gravel-packing completion technique on the Amberjack, Mississippi Canyon 109 field

    SciTech Connect

    Hannah, R.R.; Park, E.I.; Porter, D.A.; Black, J.W. )

    1994-11-01

    This paper describes a one-step fracturing/gravel-pack (frac-and-pack) completion procedure conducted on the BP Exploration Amberjack platform beginning in early 1992. This platform is 35 miles southwest of Venice, LA. The first four completions on this platform had an average positive skin values of 21. The goal of the frac-and-pack procedure was to reduce these skins to nearly zero. In total, 24 frac-and-pack operations were performed. Details of the fracture design, prefracture testing, fracture design and execution, and production response and a continuing optimization program are discussed. The fractures were performed with the screens in place with the gravel pack after the fracturing operation. The treatments were designed for the tip screenout technique to create wide fractures and to provide proppant loadings exceeding 8 lbm/ft. This paper presents the trend of the declining skin values, along with a discussion of time-dependent skins. The changes in fluids, breakers, and proppants are also presented. The average skin on 14 frac-and-pack completions was 5.3. The average skin on the final eight completions was 0.2.

  11. Fractures

    MedlinePlus

    ... commonly happen because of car accidents, falls, or sports injuries. Other causes are low bone density and osteoporosis, which cause weakening of the bones. Overuse can cause stress fractures, which are very small cracks in the ...

  12. Fractures

    MedlinePlus

    A fracture is a break, usually in a bone. If the broken bone punctures the skin, it is called an open ... falls, or sports injuries. Other causes are low bone density and osteoporosis, which cause weakening of the ...

  13. Percutaneous Arthroscopic Calcaneal Osteosynthesis: A Minimally Invasive Technique for Displaced Intra-Articular Calcaneal Fractures.

    PubMed

    Pastides, Philip S; Milnes, Lydia; Rosenfeld, Peter F

    2015-01-01

    The management of calcaneal fracture remains challenging. Open surgery has been fraught with high infection rates and soft tissue complications. More minimally invasive procedures have reduced this risk, but the patient outcomes after treatment of displaced calcaneal fractures have remained relatively unsatisfactory. We present a method for the management of Sanders grade II and III calcaneal fractures: percutaneous arthroscopic calcaneal osteosynthesis. Thirty-three fractures in 30 patients who had presented to our tertiary foot and ankle trauma center in central London were treated with percutaneous arthroscopic calcaneal osteosynthesis for calcaneal fractures, and the data were prospectively collected. The mean patient age at injury was 39 years. The mean follow-up period was 24 months. Of our patients, 58% were smokers at injury. Of the 33 fractures, 46% were classified as grade II and 54% as grade III. The mean length of stay was 1.92 days. At the final follow-up visit, the mean Böhler angle had increased from 11.10° (range 2° to 24°) to 23.41° (range 15° to 35°). The modified American Orthopaedic Foot and Ankle Society scale score was 72.18 (range 18 to 100), the calcaneal fracture scoring system score was 79.34 (range 42 to 100), and the visual analog scale score was 29.50 (range 0 to 100). We had a single case of a superficial port site infection and 2 cases of prominent screws, which were removed. No cases of deep infection developed, and no conversion to subtalar fusion was required. This technique significantly reduced the incidence of postoperative wound complications. Direct visualization of the fracture site allowed accurate restoration of the articular surface and correction of heel varus. Furthermore, it was associated with a high self-reported functional outcome and a return to preinjury employment levels. Also, the results did not appear to be influenced by tobacco consumption. PMID:25960056

  14. Novel Intramedullary-Fixation Technique for Long Bone Fragility Fractures Using Bioresorbable Materials

    PubMed Central

    Nishizuka, Takanobu; Kurahashi, Toshikazu; Hara, Tatsuya; Hirata, Hitoshi; Kasuga, Toshihiro

    2014-01-01

    Almost all of the currently available fracture fixation devices for metaphyseal fragility fractures are made of hard metals, which carry a high risk of implant-related complications such as implant cutout in severely osteoporotic patients. We developed a novel fracture fixation technique (intramedullary-fixation with biodegradable materials; IM-BM) for severely weakened long bones using three different non-metallic biomaterials, a poly(l-lactide) (PLLA) woven tube, a nonwoven polyhydroxyalkanoates (PHA) fiber mat, and an injectable calcium phosphate cement (CPC). The purpose of this work was to evaluate the feasibility of IM-BM with mechanical testing as well as with an animal experiment. To perform mechanical testing, we fixed two longitudinal acrylic pipes with four different methods, and used them for a three-point bending test (N = 5). The three-point bending test revealed that the average fracture energy for the IM-BM group (PLLA + CPC + PHA) was 3 times greater than that of PLLA + CPC group, and 60 to 200 times greater than that of CPC + PHA group and CPC group. Using an osteoporotic rabbit distal femur incomplete fracture model, sixteen rabbits were randomly allocated into four experimental groups (IM-BM group, PLLA + CPC group, CPC group, Kirschner wire (K-wire) group). No rabbit in the IM-BM group suffered fracture displacement even under full weight bearing. In contrast, two rabbits in the PLLA + CPC group, three rabbits in the CPC group, and three rabbits in the K-wire group suffered fracture displacement within the first postoperative week. The present work demonstrated that IM-BM was strong enough to reinforce and stabilize incomplete fractures with both mechanical testing and an animal experiment even in the distal thigh, where bone is exposed to the highest bending and torsional stresses in the body. IM-BM can be one treatment option for those with severe osteoporosis. PMID:25111138

  15. Development of experimental verification techniques for non-linear deformation and fracture.

    SciTech Connect

    Moody, Neville Reid; Bahr, David F.

    2003-12-01

    This project covers three distinct features of thin film fracture and deformation in which the current experimental technique of nanoindentation demonstrates limitations. The first feature is film fracture, which can be generated either by nanoindentation or bulge testing thin films. Examples of both tests will be shown, in particular oxide films on metallic or semiconductor substrates. Nanoindentations were made into oxide films on aluminum and titanium substrates for two cases; one where the metal was a bulk (effectively single crystal) material and the other where the metal was a 1 pm thick film grown on a silica or silicon substrate. In both cases indentation was used to produce discontinuous loading curves, which indicate film fracture after plastic deformation of the metal. The oxides on bulk metals fractures occurred at reproducible loads, and the tensile stress in the films at fracture were approximately 10 and 15 GPa for the aluminum and titanium oxides respectively. Similarly, bulge tests of piezoelectric oxide films have been carried out and demonstrate film fracture at stresses of only 100's of MPa, suggesting the importance of defects and film thickness in evaluating film strength. The second feature of concern is film adhesion. Several qualitative and quantitative tests exist today that measure the adhesion properties of thin films. A relatively new technique that uses stressed overlayers to measure adhesion has been proposed and extensively studied. Delamination of thin films manifests itself in the form of either telephone cord or straight buckles. The buckles are used to calculate the interfacial fracture toughness of the film-substrate system. Nanoindentation can be utilized if more energy is needed to initiate buckling of the film system. Finally, deformation in metallic systems can lead to non-linear deformation due to 'bursts' of dislocation activity during nanoindentation. An experimental study to examine the structure of dislocations around

  16. Alternative electronic logging technique locates fractures in Austin chalk horizontal well

    SciTech Connect

    Stang, C.W. )

    1989-11-01

    This article describes the search for a technique to locate fractures in a horizontal well. The author focuses on the utilization of a formation microscanner (FMS). The FMS is described and the results and problems associated with its utilization are presented.

  17. [A new locking nail for proximal humerus fractures: the Telegraph nail, technique and preliminary results].

    PubMed

    Cuny, C; Pfeffer, F; Irrazi, M; Chammas, M; Empereur, F; Berrichi, A; Metais, P; Beau, P

    2002-02-01

    We present a new nail, the telegraph nail, designed for the treatment of proximal fractures of the humerus. This nail has a new locking system providing a self-stabilization of the cancelous screws inserted in small fragments. We discuss the surgical technique and present preliminary results. The anterolateral approach and nail insertion through the medial and well vascularized part of the cuff is described for simple fractures. With the cup and ball technique, this nail can also be used for complex fractures of the proximal humerus with three or four fragments and major displacement. With this method, the nail is inserted before reduction and locked in the distal humerus before fixation of the head and tuberosities around the head once the targeting device removed. We report results for the first 64 nails inserted in our unit during the first year (1998-1999). Outcome was assessed at 11 months mean follow-up using the Constant score. Outcome was favorable, including in patients with complex fractures involving 3 or 4 separate displaced fragments. Besides providing an anatomically stable reconstruction, the telegraph nail has the advantage of allowing early mobilization of the shoulder joint. This method is a useful alternative to prosthetic reconstruction for traumatic fractures of the proximal humerus. PMID:11973536

  18. Fracture Resistance of Premolars Restored by Various Types and Placement Techniques of Resin Composites

    PubMed Central

    Moosavi, Horieh; Zeynali, Mahsa; Pour, Zahra Hosseini

    2012-01-01

    To verify the fracture resistance of premolars with mesioocclusodistal preparations restored by different resin composites and placement techniques. Sixty premolars were randomly divided into two groups based on type of composite resin: Filtek P60 or Nulite F, and then each group was separated into three subgroups: bulk, centripetal, and fiber insert according to the type of placement method (n = 10). Single-bond adhesive system was used as composite bonding according to the manufacturer's instructions. Specimens were restored in Groups 1, 2, and 3 with Filtek P60 and in Groups 4, 5, and 6 with Nulite F. After being stored 24 hours at 37°C, a 4 mm diameter steel sphere in a universal testing machine was applied on tooth buccal and lingual cusps at a cross-head speed of 5 mm/min until fracture occurred. Groups 3 and 6 showed higher fracture resistance than Groups 1, 2, 4, and 5. Among the placement techniques, the fiber insert method had a significant effect, but the type of composite was ineffective. The insertion technique in contrast to the type of material had a significant influence on the fracture resistance of premolar teeth. PMID:22666255

  19. The submuscular sliding plate technique for acetabular posterior wall fractures extending to the acetabular roof.

    PubMed

    Kim, J J; Kim, J W; Oh, H K

    2014-12-01

    There is extension of the Kocher-Langenbeck approach using trochanteric osteotomy for posterior wall fracture extending to acetabular roof, but it exposes to complications such as nonunion, breakage, and heterotopic ossification. The current study introduces a submuscular sliding plate technique. We retrospectively analyzed 13 patients treated with this technique. It is based on conventional method for posterior wall fracture. After reduction of roof fragment with direct visualization, a pre-contoured plate was passed through a submuscular tunnel under the gluteus medius and minimus. A small split incision was performed on the muscles, and screws were inserted with a triple trocar complex safely under fluoroscopic imaging. All patients had fracture union without complications. X-rays results showed anatomical reduction in 10 cases and imperfect reduction in 3 cases. Our results were satisfactory, particularly without heterotopic ossifications despite no prophylactic regimen of NSAID was applied and no neurological complications, so we believe that this technique is a good option for posterior wall fractures extending to the acetabular roof. PMID:25453921

  20. Application of a new multiple fracturing technique to enhance gas production in Devonian shale

    SciTech Connect

    Cuderman, J.F.

    1984-01-01

    A new multiple fracturing technology has been applied in stimulating a Devonian shale gas well. In this new technique, propellants are used to obtain controlled pressurization of the wellbore to produce multiple fractures. The pressurization is controlled by suitable choice of propellants having different burn rates. The pressure risetime is the most important parameter governing fracture behavior. Methods are presented for specifying both the risetime and propellants to achieve it for Devonian shales. The Devonian shale stimulation was conducted in a 1040 m deep well in Meigs Co., Ohio. The experimental installation and hardware used are described together with results which include an increase in production from 190 m/sup 3//day to 623 m/sup 3//day. 7 references, 5 figures, 1 table.

  1. Development of experimental verification techniques for non-linear deformation and fracture on the nanometer scale.

    SciTech Connect

    Moody, Neville Reid; Bahr, David F.

    2005-11-01

    This work covers three distinct aspects of deformation and fracture during indentations. In particular, we develop an approach to verification of nanoindentation induced film fracture in hard film/soft substrate systems; we examine the ability to perform these experiments in harsh environments; we investigate the methods by which the resulting deformation from indentation can be quantified and correlated to computational simulations, and we examine the onset of plasticity during indentation testing. First, nanoindentation was utilized to induce fracture of brittle thin oxide films on compliant substrates. During the indentation, a load is applied and the penetration depth is continuously measured. A sudden discontinuity, indicative of film fracture, was observed upon the loading portion of the load-depth curve. The mechanical properties of thermally grown oxide films on various substrates were calculated using two different numerical methods. The first method utilized a plate bending approach by modeling the thin film as an axisymmetric circular plate on a compliant foundation. The second method measured the applied energy for fracture. The crack extension force and applied stress intensity at fracture was then determined from the energy measurements. Secondly, slip steps form on the free surface around indentations in most crystalline materials when dislocations reach the free surface. Analysis of these slip steps provides information about the deformation taking place in the material. Techniques have now been developed to allow for accurate and consistent measurement of slip steps and the effects of crystal orientation and tip geometry are characterized. These techniques will be described and compared to results from dislocation dynamics simulations.

  2. An inverse technique for developing models for fluid flow in fracture systems using simulated annealing

    SciTech Connect

    Mauldon, A.D.; Karasaki, K.; Martel, S.J.; Long, J.C.S.; Landsfield, M.; Mensch, A. ); Vomvoris, S. )

    1993-11-01

    One of the characteristics of flow and transport in fractured rock is that the flow may be largely confined to a poorly connected network of fractures. In order to represent this condition, Lawrence Berkeley Laboratory has been developing a new type of fracture hydrology model called an equivalent discontinuum model. In this model we represent the discontinuous nature of the problem through flow on a partially filled lattice. This is done through a statistical inverse technique called [open quotes]simulated annealing.[close quotes] The fracture network model is [open quotes]annealed[close quotes] by continually modifying a base model, or [open quotes]template,[close quotes] so that with each modification, the model behaves more and more like the observed system. This template is constructed using geological and geophysical data to identify the regions that possibly conduct fluid an the probable orientations of channels that conduct fluid. In order to see how the simulated annealing algorithm works, we have developed a synthetic case. In this case, the geometry of the fracture network is completely known, so that the results of annealing to steady state data can be evaluated absolutely. We also analyze field data from the Migration Experiment at the Grimsel Rock Laboratory in Switzerland. 28 refs., 14 figs., 3 tabs.

  3. Application of iterative path revision technique for laser cutting with controlled fracture

    NASA Astrophysics Data System (ADS)

    Tsai, Chwan-Huei; Chen, Chien-Jen

    2004-01-01

    Laser cutting using the controlled fracture technique has great potential to be employed for the ceramic substrate machining. The heat produced on the surface of a ceramic substrate by the laser separates the substrate controllably along the moving path of the laser beam. Because the extension of the breaking frontier is lager than the movement of the laser spot, the actual fracture trajectory deviates from the desired trajectory when cutting a curve or cutting an asymmetrical straight line. To eliminate this deviation, the iterative learning control method is introduced to obtain the optimal laser beam movement path. The fracture contour image is grabbed by a CCD camera after laser cutting completion. A new image processing system is proposed to detect the deviation between the desired cutting path and the actual fracture trajectory. The laser-movement path for the next trial can then be determined according to the iterative path revision algorithm. The actual fracture trajectory converging to the desired cutting path is assured after a few path revisions. The experimental materials used in these experiments are alumina ceramics and the laser source is CO 2 laser. The proposed system can achieve a machining precision of about 0.1 mm.

  4. Minimally invasive reconstruction of lateral tibial plateau fractures using the jail technique: a biomechanical study

    PubMed Central

    2013-01-01

    Background This study described a novel, minimally invasive reconstruction technique of lateral tibial plateau fractures using a three-screw jail technique and compared it to a conventional two-screw osteosynthesis technique. The benefit of an additional screw implanted in the proximal tibia from the anterior at an angle of 90° below the conventional two-screw reconstruction after lateral tibial plateau fracture was evaluated. This new method was called the jail technique. Methods The two reconstruction techniques were tested using a porcine model (n = 40). Fracture was simulated using a defined osteotomy of the lateral tibial plateau. Load-to-failure and multiple cyclic loading tests were conducted using a material testing machine. Twenty tibias were used for each reconstruction technique, ten of which were loaded in a load-to-failure protocol and ten cyclically loaded (5000 times) between 200 and 1000 N using a ramp protocol. Displacement, stiffness and yield load were determined from the resulting load displacement curve. Failure was macroscopically documented. Results In the load-to-failure testing, the jail technique showed a significantly higher mean maximum load (2275.9 N) in comparison to the conventional reconstruction (1796.5 N, p < 0.001). The trend for better outcomes for the novel technique in terms of stiffness and yield load did not reach statistical significance (p > 0.05). In cyclic testing, the jail technique also showed better trends in displacement that were not statistically significant. Failure modes showed a tendency of screws cutting through the bone (cut-out) in the conventional reconstruction. No cut-out but a bending of the lag screws at the site of the additional third screw was observed in the jail technique. Conclusions The results of this study indicate that the jail and the conventional technique have seemingly similar biomechanical properties. This suggests that the jail technique may be a feasible alternative to

  5. Biomechanical Evaluation of a Mandibular Spanning Plate Technique Compared to Standard Plating Techniques to Treat Mandibular Symphyseal Fractures

    PubMed Central

    Richardson, Matthew; Hayes, Jonathan; Jordan, J. Randall; Puckett, Aaron; Fort, Matthew

    2015-01-01

    Purpose. The purpose of this study is to compare the biomechanical behavior of the spanning reconstruction plate compared to standard plating techniques for mandibular symphyseal fractures. Materials and Methods. Twenty-five human mandible replicas were used. Five unaltered synthetic mandibles were used as controls. Four experimental groups of different reconstruction techniques with five in each group were tested. Each synthetic mandible was subjected to a splaying force applied to the mandibular angle by a mechanical testing unit until the construct failed. Peak load and stiffness were recorded. The peak load and stiffness were analyzed using ANOVA and the Tukey test at a confidence level of 95% (P < 0.05). Results. The two parallel plates' group showed statistically significant lower values for peak load and stiffness compared to all other groups. No statistically significant difference was found for peak load and stiffness between the control (C) group, lag screw (LS) group, and the spanning plate (SP1) group. Conclusions. The spanning reconstruction plate technique for fixation of mandibular symphyseal fractures showed similar mechanical behavior to the lag screw technique when subjected to splaying forces between the mandibular gonial angles and may be considered as an alternative technique when increased reconstructive strength is needed. PMID:26649332

  6. A Novel Technique for Closed Reduction and Fixation of Paediatric Calcaneal Fracture Dislocation Injuries

    PubMed Central

    Faroug, Radwane; Stirling, Paul; Ali, Farhan

    2013-01-01

    Paediatric calcaneal fractures are rare injuries usually managed conservatively or with open reduction and internal fixation (ORIF). Closed reduction was previously thought to be impossible, and very few cases are reported in the literature. We report a new technique for closed reduction using Ilizarov half-rings. We report successful closed reduction and screwless fixation of an extra-articular calcaneal fracture dislocation in a 7-year-old boy. Reduction was achieved using two Ilizarov half-ring frames arranged perpendicular to each other, enabling simultaneous application of longitudinal and rotational traction. Anatomical reduction was achieved with restored angles of Bohler and Gissane. Two K-wires were the definitive fixation. Bony union with good functional outcome and minimal pain was achieved at eight-weeks follow up. ORIF of calcaneal fractures provides good functional outcome but is associated with high rates of malunion and postoperative pain. Preservation of the unique soft tissue envelope surrounding the calcaneus reduces the risk of infection. Closed reduction prevents distortion of these tissues and may lead to faster healing and mobilisation. Closed reduction and screwless fixation of paediatric calcaneal fractures is an achievable management option. Our technique has preserved the soft tissue envelope surrounding the calcaneus, has avoided retained metalwork related complications, and has resulted in a good functional outcome. PMID:23819090

  7. Fracture of distal humerus: MIPO technique with visualization of the radial nerve

    PubMed Central

    Zogbi, Daniel Romano; Terrivel, Alberto Maranon; Mouraria, Guilherme Grisi; Mongon, Maurício Leal Dias; Kikuta, Fernando Kenji; Filho, Américo Zoppi

    2014-01-01

    OBJECTIVES: To evaluate the outcomes in patients treated for humerus distal third fractures with MIPO technique and visualization of the radial nerve by an accessory approach, in those without radial palsy before surgery. METHODS: The patients were treated with MIPO technique. The visualization and isolation of the radial nerve was done by an approach between the brachialis and the brachiorradialis, with an oblique incision, in the lateral side of the arm. MEPS was used to evaluate the elbow function. RESULTS: Seven patients were evaluated with a mean age of 29.8 years old. The average follow up was 29.85 months. The radial neuropraxis after surgery occurred in three patients. The sensorial recovery occurred after 3.16 months on average and also of the motor function, after 5.33 months on average, in all patients. We achieved fracture consolidation in all patients (M=4.22 months). The averages for flexion-extension and prono-supination were 112.85° and 145°, respectively. The MEPS average score was 86.42. There was no case of infection. CONCLUSION: This approach allowed excluding a radial nerve interposition on site of the fracture and/or under the plate, showing a high level of consolidation of the fracture and a good evolution of the range of movement of the elbow. Level of Evidence IV, Case Series PMID:25538474

  8. Stent strut fracture-induced restenosis in a bifurcation lesion treated with the crush stenting technique.

    PubMed

    Surmely, Jean-Francois; Kinoshita, Yoshihisa; Dash, Debabrata; Matsubara, Tetsuo; Terashima, Mitsuyasu; Ehara, Mariko; Ito, Tatsuya; Nasu, Kenya; Takeda, Yoshihiro; Tanaka, Nobuyoshi; Suzuki, Takahiko; Katoh, Osamu

    2006-07-01

    Percutaneous treatment of a bifurcation lesion still shows a significant complication rate, mainly because of restenosis at the ostial site of the side branch vessel. Different techniques, such as V-stenting, culottes-stenting or crush stenting, allow full ostial coverage and may therefore achieve uniform drug distribution within the lesion. The crush technique results in a strong mechanical constraint on the side branch stent. A case of stent strut fracture-induced restenosis in a bifurcation lesion treated with the crush stenting technique is described. PMID:16799252

  9. Arthroscopic treatment of avulsed tibial spine fractures using a transosseous sutures technique.

    PubMed

    Wagih, Ahmad M

    2015-03-01

    Severely displaced tibial spine fractures should be treated surgically to restore joint congruity and cruciate integrity with reduction and fixation through an arthrotomy or arthroscopic techniques. Arthroscopy is preferred as it allows for accurate diagnosis and treatment of associated injuries and reduction and fixation of all types of tibial spine fractures while reducing the morbidity associated with open techniques. We report the clinical and radiographical results of 11 cases treated with a technique of arthroscopic internal fixation with non-absorbable sutures, after an average follow-up of 16.3 months (range, 11 to 21 months). The clinical examination using the IKDC system revealed all patients to have a negative Lachman test and no quadriceps weakness except one patient with some laxity (hard end 1+ Lachman test). One patient had a minor extension deficit of approximately 5°. The other patients showed a full range of motion without extension loss. This technique is simple, reproducible and very useful in dealing with these fractures. PMID:26280867

  10. New Technique for Dorsal Fragment Reduction in Distal Radius Fractures by Using Volar Bone Fenestration

    PubMed Central

    TSUCHIYA, Fumika; NAITO, Kiyohito; MOGAMI, Atsuhiko; OBAYASHI, Osamu

    2013-01-01

    Introduction: For intra-articular distal radius fractures (AO Classification, type B2) with a displaced dorsal fragment, there remains much discussion on the fixation method for the dorsal fragment. To reduce the displaced dorsal fragment, we developed a new technique consisting of fenestration of the volar bone cortex, reduction using an intramedullary procedure, and fixation using a volar plate. This avoids necessity of dorsal approach. Technical Note: We performed this surgical technique in 2 patients and achieved a good reduced position without much injury to the bone cortex at the site of volar plate placement. This surgical technique allows reduction of the dorsal fragment using an intramedullary procedure by only a volar approach, and, therefore, does not affect the dorsal soft tissue (extensor tendon). For intra-articular distal radius fractures, complete reduction of the articular surface is extremely difficult, and, in patients with a remaining gap on the articular surface, a variable angle locking screw system may be useful. In the 2 patients, the angle of the locking screw was adjusted to catch the displaced dorsal fragment, and adequate reduction and fixation could be achieved. Conclusion: This technique using fenestration of the volar bone cortex allows reduction and fixation of the displaced dorsal fragment in distal radius fractures and thus avoids the necessity of a dorsal approach. PMID:27298898

  11. Phosphate laser glass for NIF: production status, slab selection, and recent technical advances

    NASA Astrophysics Data System (ADS)

    Suratwala, Tayyab I.; Campbell, John H.; Miller, Philip E.; Thorsness, Charles B.; Riley, Michael O.; Ehrmann, Paul R.; Steele, Rusty A.

    2004-05-01

    The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory is a stadium-sized high-energy (1.8 megajoule) / high-peak power (500 terawatt) laser system, which will utilize over 3000 meter-size Nd-doped metaphosphate glasses as its gain media. The current production status, the selection criteria of individual slabs for specific beam line locations, and some recent technical advances are reviewed. The glass blanks are manufactured by a novel continuous glass melting process, and the finished slabs are then prepared by epoxy bonding a Cu-doped phosphate glass edge cladding and by advanced finishing techniques. To date, nearly 3400 slab equivalents have been melted, 2600 have been rough-cut to blanks, 1200 have been finished, and 144 have been installed in NIF. A set of selection rules, which are designed to optimize laser performance (e.g., maintain gain balance between beam lines and minimize beam walkoff) and to maximize glass lifetime with respect to Pt damage site growth, have been established for assigning individual slabs to specific beam line locations. Recent technical advances for amplifier slab production, which include: 1) minimizing surface pitting (hazing) after final finishing; 2) minimizing humidity-induced surface degradation (weathering) upon storage and use; and 3) preventing mounting-induced surface fractures upon installation, have contributed in improving the laser glass quality.

  12. Triangular Fixation Technique for Bicolumn Restoration in Treatment of Distal Humerus Intercondylar Fracture

    PubMed Central

    Kang, Seung-Hoon; Jeong, Min; Lim, Hae-Seong

    2016-01-01

    Background Distal humerus intercondylar fractures are intra-articular and comminuted fractures involving soft tissue injury. As distal humerus is triangle-shaped, parallel plating coupled with articular fixation would be suitable for bicolumn restoration in treatment of distal humerus intercondylar fracture. Methods This study included 38 patients (15 males and 23 females) who underwent olecranon osteotomy, open reduction and internal fixation with the triangle-shaped cannulated screw and parallel locking plates (triangular fixation technique). Functional results were assessed with the visual analog scale (VAS) scores, Mayo elbow performance (MEP) scores and Disabilities of the Arm, Shoulder and Hand (DASH) questionnaires. Anteroposterior and lateral elbow radiographs were assessed for reduction, alignment, fracture union, posttraumatic arthrosis, and heterotopic ossification, and computed tomography (CT) scans were used to obtain more accurate measurements of articular discrepancy. Results All fractures healed primarily with no loss of reduction. The mean VAS, MEP, and DASH scores of the affected elbow were not significantly different from those of the unaffected elbow (p = 0.140, p = 0.090, and p = 0.262, respectively). The mean degree of flexion was significantly lower in the affected elbow than in the unaffected elbow, but was still considered as functional (p = 0.001, > 100° in 33 of 38 patients). Two cases of articular step-offs (> 2 mm) were seen on follow-up CT scans, but not significantly higher in the affected elbow than in the unaffected elbow (p = 0.657). Binary logistic regression analysis revealed that only Association for Osteosynthesis (AO) type C3 fractures correlated with good/excellent functional outcome (p = 0.012). Complications occurred in 12 of the 38 patients, and the overall reoperation rate for complications was 10.5% (4 of 38 patients). Conclusions Triangular fixation technique for bicolumn restoration was an effective and reliable

  13. Do Elderly Patients Fare Worse Following Operative Treatment of Distal Femur Fractures Using Modern Techniques?

    PubMed Central

    Shulman, Brandon S.; Patsalos-Fox, Bianka; Lopez, Nicole; Konda, Sanjit R.; Tejwani, Nirmal C.; Egol, Kenneth A.

    2014-01-01

    Background: The purpose of this study was to compare the functional outcomes and quality of life of older and younger patients with similarly treated distal femur fractures. Methods: We conducted an assessment of 57 patients who sustained distal femur fractures (Orthopaedic Trauma Association Type 33B, C) and underwent surgical treatment at our academic medical center. Patients were divided into 2 groups for analysis: an elderly cohort of patients aged 65 or older and a comparison cohort of patients younger than age of 65. A retrospective review of demographics, preoperative ambulatory status, radiographic data, and physical examination data was collected from the medical records. Follow-up functional data were collected via telephone at a mean of 2.5 years (range 6 months-8 years) using a Short Musculoskeletal Functional Assessment (SMFA). All patients underwent standard operative treatment of either nail or plate fixation. Results: There was no statistical difference in gender, fracture type, surgical technique, surgeon, or institution where the surgery was performed. The percentage of patients with healed fractures at 6-months follow-up was not significantly different between the cohorts. The elderly cohort had slightly worse knee range of motion at 3, 6, and 12 months postoperatively but there was not a statistically significant difference between the groups. The SMFA Daily Activity, Functional, and Bother indices were significantly worse in the older cohort (P < .01, P = .01, P = .02, respectively). However, there was no significant difference in the SMFA Emotional or Mobility indices. Conclusion: Despite lower quality of life and functional scores, this study suggests that relatively good clinical outcomes can be achieved with surgical fixation of distal femoral fractures in the elderly patients. Age should not be used as a determinate in deciding against operative treatment of distal femur fractures in the elderly patients. PMID:24660097

  14. Distal humerus shear-fractures: “Built-on” surgical technique

    PubMed Central

    Rapariz, Jose M.; Martin, Silvia; Far-Riera, Aina; Lirola-Palmero, Serafin

    2014-01-01

    When treating a distal humeral shear fracture, comminution of the lateral column may preclude the reconstruction of the lateral articular fragments. In this article a new strategy for the management lateral column comminuted shear-fractures (LCCSF) is presented, called the “built-on” surgical technique. Three goals are obtained by this technique: (1) Restoration of the lateral column bone stock; (2) Provision of a solid scaffold for the repair of the lateral ulnar collateral ligament (LUCL); and (3) Provision of a sable platform for the reconstruction and fixation of the articular fragments. We will obtain these goals through the following surgical steps: 1/ Reconstruction of the lateral trochlea. 2/ Reconstruction of the lateral column 3/ Fixation of the Capitellum 4/ Reconstruction of the LUCL PMID:24926163

  15. Efficacy of minimally invasive techniques for enhancement of fracture healing: evidence today

    PubMed Central

    Pountos, Ippokratis; Georgouli, Theodora; Kontakis, George

    2009-01-01

    The successful treatment of nonunions represents a major challenge for orthopaedic surgeons. Lately, ongoing advances made in the field of molecular medicine and molecular biology have increased our understanding of the pathways and involvement of mediators surrounding the bone healing process. As a result, the surgeon’s armamentarium has been increased in terms of options for intervention. This article aims to provide an overview of minimally invasive techniques applicable in the treatment of nonunions of fractures. PMID:19844709

  16. Lordoplasty: midterm outcome of an alternative augmentation technique for vertebral fractures.

    PubMed

    Hoppe, Sven; Budmiger, Mathias; Bissig, Philipp; Aghayev, Emin; Benneker, Lorin M

    2016-06-01

    OBJECTIVE Vertebroplasty and balloon kyphoplasty are effective treatment options for osteoporotic vertebral compression fractures but are limited in correction of kyphotic deformity. Lordoplasty has been reported as an alternative, cost-effective, minimally invasive, percutaneous cement augmentation technique with good restoration of vertebral body height and alignment. The authors report on its clinical and radiological midterm results. METHODS A retrospective review was conducted of patients treated with lordoplasty from 2002 to 2014. Inclusion criteria were clinical and radiological follow-up evaluations longer than 24 months. Radiographs were accessed regarding initial correction and progressive loss of reduction. Complications and reoperations were recorded. Actual pain level, pain relief immediately after surgery, autonomy, and subjective impression of improvement of posture were assessed by questionnaire. RESULTS Sixty-five patients (46 women, 19 men, age range 38.9-86.2 years old) were treated with lordoplasty for 69 vertebral compression and insufficiency fractures. A significant correction of the vertebral kyphotic angle (mean 13°) and segmental kyphotic angle (mean 11°) over a mean follow-up of 33 months (range 24-108 months) was achieved (p < 0.001). On average, pain was relieved to 90% of the initial pain level. In 24% of the 65 patients a second spinal intervention was necessary: 16 distant (24.6%) and 7 adjacent (10.8%) new osteoporotic fractures, 4 instrumented stabilizations (6.2%), 1 new adjacent traumatic fracture (1.5%), and 1 distant microsurgical decompression (1.5%). Cement leakage occurred in 10.4% but was only symptomatic in 1 case. CONCLUSIONS Lordoplasty appeared safe and effective in midterm pain alleviation and restoration of kyphotic deformity in osteoporotic compression and insufficiency fractures. The outcomes of lordoplasty are consistent with other augmentation techniques. PMID:26895528

  17. Cusp Fracture Resistance of Maxillary Premolars Restored with the Bonded Amalgam Technique Using Various Luting Agents

    PubMed Central

    Marchan, Shivaughn M.; Coldero, Larry; White, Daniel; Smith, William A. J.; Rafeek, Reisha N.

    2009-01-01

    Objective. This in vitro study uses measurements of fracture resistance to compare maxillary premolars restored with the bonded amalgam technique using a new resin luting cement, glass ionomer, and resin-modified glass ionomer as the bonding agents. Materials. Eighty-five sound maxillary premolars were selected and randomly assigned to one of five test groups of 17 teeth each. One group of intact teeth served as the control. The remaining groups were prepared to a standard cavity form relative to the dimensions of the overall tooth and restored with amalgam alone or a bonded amalgam using one of three luting agents: RelyX Arc (a new resin luting cement), RelyX luting (a resin-modified glass ionomer), or Ketac-Cem μ (a glass ionomer) as the bonding agents. Each tooth was then subjected to compressive testing until catastrophic failure occurred. The mean loads at failure of each group were statistically compared using ANOVA with a post hoc Bonferroni test. Results. It was found that regardless of the luting cement used for the amalgam bonding technique, there was little effect on the fracture resistance of teeth. Conclusion. Cusp fracture resistance of premolars prepared with conservative MOD cavity preparations is not improved by using an amalgam-bonding technique compared to similar cavities restored with amalgam alone. PMID:20339450

  18. Use of 2D and 3D Imaging Techniques to Understand Fracture Growth

    NASA Astrophysics Data System (ADS)

    Lockner, D. A.

    2004-05-01

    The monitoring of acoustic emissions (AE) is a valuable tool for studying the brittle fracture process in rock. With the improved characterization of transducer response, researchers are able to apply a broad spectrum of seismological techniques to AE catalogues collected in the laboratory; i.e., moment tensor analysis, Vp/Vs ratios, attenuation, event clustering statistics, Gutenberg-Richter b-value and aftershock analysis. Since AE occurs spontaneously as a result of unstable microcrack growth during rock deformation experiments, it provides a non-destructive method to observe damage accumulation. I will give examples of visualization techniques that have proven helpful in the analysis of fracture nucleation and growth based on 3D event locations in granite and sandstone samples. These techniques are useful in interpreting the development of complex fracture systems in lab samples. Complementary measurements of wave speed anisotropy and heterogeneity are used to infer both the development of damage zones and the rate of infiltration of water during fluid injection experiments. Finally, spatial clustering of AE events is evaluated in terms of the surface roughness of reactivated faults during triaxial deformation experiments.

  19. Inverse measurement of stiffness by the normalization technique for J-integral fracture toughness

    SciTech Connect

    Brown, Eric

    2012-06-07

    The single specimen normalization technique for J-integral fracture toughness has been successfully employed by several researchers to study the strongly non-linear fracture response of ductile semicrystalline polymers. As part of the normalization technique the load and the plastic component of displacement are normalized. The normalized data is then fit with a normalization function that approximates a power law for small displacements that are dominated by blunting and smoothly transitions to a linear relationship for large displacements that are dominated by stable crack extension. Particularly for very ductile polymers the compliance term used to determine the plastic displacement can dominate the solution and small errors in determining the elastic modulus can lead to large errors in the normalization or even make it ill-posed. This can be further complicated for polymers where the elastic modulus is strong strain rate dependent and simply using a 'quasistatic' modulus from a dogbone measurement may not equate to the dominant strain rate in the compact tension specimen. The current work proposes directly measuring the compliance of the compact tension specimen in the solution of J-integral fracture toughness and then solving for the elastic modulus. By comparison with a range of strain rate data the dominant strain rate can then be determined.

  20. Fracture analysis of plastic-bonded explosive by digital image correlation technique

    NASA Astrophysics Data System (ADS)

    Li, M.; Zhang, J.; Xiong, Chun-Yang; Fang, J.; Hao, Y.; Wen, M. P.

    2002-05-01

    Plastic-bonded explosive is a kind of energy material used in military and civil engineering. It serves also as structures or components to sustain external loads. Safety and reliability of the material is of importance to prevent damage and fracture during both manufacturing and usage procedure. Digital image correlation technique was applied to analyze the deformation field of the material near crack tip. The specimen was loaded by uniaxial compression and a slot was preset at the specimen edge with 45 degrees orientation. The speckle images were captured during the load and the surface patterns were matched by correlation computation to obtain the displacement components. The stress intensity factors of the crack tip were evaluated by the deformation in the near region of the crack. By the comparison of the strain field and the surface profile, the damage form of the material can be analyzed that showed brittle behavior with axial splitting fracture.

  1. A revisit to high-rate mode-II fracture characterization of composites with Kolsky bar techniques.

    SciTech Connect

    Lu, Wei-Yang; Song, Bo; Jin, Huiqing

    2010-03-01

    Nowadays composite materials have been extensively utilized in many military and industrial applications. For example, the newest Boeing 787 uses 50% composite (mostly carbon fiber reinforced plastic) in production. However, the weak delamination strength of fiber reinforced composites, when subjected to external impact such as ballistic impact, has been always potential serious threats to the safety of passengers. Dynamic fracture toughness is a critical indicator of the performance from delamination in such impact events. Quasi-static experimental techniques for fracture toughness have been well developed. For example, end notched flexure (ENF) technique, which is illustrated in Fig. 1, has become a typical method to determined mode-II fracture toughness for composites under quasi-static loading conditions. However, dynamic fracture characterization of composites has been challenging. This has resulted in conflictive and confusing conclusions in regard to strain rate effects on fracture toughness of composites.

  2. Building Quakes: Detection of Weld Fractures in Buildings using High-Frequency Seismic Techniques

    NASA Astrophysics Data System (ADS)

    Heckman, V.; Kohler, M. D.; Heaton, T. H.

    2009-12-01

    Catastrophic fracture of welded beam-column connections in buildings was observed in the Northridge and Kobe earthquakes. Despite the structural importance of such connections, it can be difficult to locate damage in structural members underneath superficial building features. We have developed a novel technique to locate fracturing welds in buildings in real time using high-frequency information from seismograms. Numerical and experimental methods were used to investigate an approach for detecting the brittle fracture of welds of beam-column connections in instrumented steel moment-frame buildings through the use of time-reversed Green’s functions and wave propagation reciprocity. The approach makes use of a prerecorded catalogue of Green’s functions for an instrumented building to detect high-frequency failure events in the building during a later earthquake by screening continuous data for the presence of one or more of the events. This was explored experimentally by comparing structural responses of a small-scale laboratory structure under a variety of loading conditions. Experimentation was conducted on a polyvinyl chloride frame model structure with data recorded at a sample rate of 2000 Hz using piezoelectric accelerometers and a 24-bit digitizer. Green’s functions were obtained by applying impulsive force loads at various locations along the structure with a rubber-tipped force transducer hammer. We performed a blind test using cross-correlation techniques to determine if it was possible to use the catalogue of Green’s functions to pinpoint the absolute times and locations of subsequent, induced failure events in the structure. A finite-element method was used to simulate the response of the model structure to various source mechanisms in order to determine the types of elastic waves that were produced as well as to obtain a general understanding of the structural response to localized loading and fracture.

  3. Preliminary stress measurements in central California using the hydraulic fracturing technique

    USGS Publications Warehouse

    Zoback, M.D.; Healy, J.H.; Roller, J.C.

    1977-01-01

    Use of the hydraulic fracturing technique for determining in situ stress is reviewed, and stress measurements in wells near the towns of Livermore, San Ardo, and Menlo Park, California are described in detail. In the Livermore well, four measurements at depths between 110 and 155 m indicate that the least principal compressive stress is horizontal and increases from 1.62 to 2.66 MPa. The apparent direction of maximum compression is N 70?? E (??40??). At the San Ardo site the least principal stress is that due to the overburden weight. At depths of 240.2 and 270.7 m the minimum and maximum horizontal stresses are estimated to be 11.4 and 22.5 MPa, and 12.0 (??1.1) and 15.8 (??3.3) MPa, respectively. From an impression of the fracture at 240.2 m, the direction of maximum compression appears to be about N 15?? E. The rock in the Menlo Park well is too highly fractured to yield a reliable measurement of the horizontal stresses. The data indicate, however, that the least principal stress is vertical (due to the overburden weight) to a depth of 250 m. ?? 1977 Birkha??user Verlag.

  4. Study of fracture mechanisms of short fiber reinforced AS composite by acoustic emission technique

    SciTech Connect

    Kida, Sotoaki; Suzuki, Megumu

    1995-11-01

    The fracture mechanisms of short fiber reinforced AS composites are studied by acoustic emission technique for examining the effects of fiber contents. The loads P{sub b} and P{sub c} which the damage mechanisms change are obtained at the inflection points of the total AE energy curve the energy gradient method. The damages are generated by fiber breaking at the load point of P{sub b} and P{sub c} in B material, and by the fiber breaking and the debonding between resin and fiber at the load points of P{sub b} and P{sub c} in C material.

  5. Mason type 3 radial head fractures: proposal of a synthesis technique using bioabsorbable thread

    PubMed Central

    SALVI, ANDREA EMILIO

    2016-01-01

    Multifragmentary fractures of the radial head (Mason type 3) are challenging for the surgeon. They are usually treated by means of complete removal of the injured head and sometimes by implantation of a metal prosthesis. Indeed, the bone fragments are often too small to allow stabilization through screws or even wires. The Author proposes an alternative technique, tested on a sawbone model, in which bioabsorbable thread is used, introduced in a figure-of-eight fashion. A review of the literature is provided. PMID:27602353

  6. Mason type 3 radial head fractures: proposal of a synthesis technique using bioabsorbable thread.

    PubMed

    Salvi, Andrea Emilio

    2016-01-01

    Multifragmentary fractures of the radial head (Mason type 3) are challenging for the surgeon. They are usually treated by means of complete removal of the injured head and sometimes by implantation of a metal prosthesis. Indeed, the bone fragments are often too small to allow stabilization through screws or even wires. The Author proposes an alternative technique, tested on a sawbone model, in which bioabsorbable thread is used, introduced in a figure-of-eight fashion. A review of the literature is provided. PMID:27602353

  7. Evaluation of occlusal fracture resistance of three different core materials using the Nayyar core technique

    PubMed Central

    Reddy, Satti Narayana; Harika, Kolli; Manjula, Shobha; Chandra, Pavani; Vengi, Lokesh; Koka, Krishna Mohan

    2016-01-01

    Aim: The aim and purpose of this study was to determine the occlusal fracture resistance of three core buildup materials using the Nayyar technique. Materials and Methods: Thirty human extracted maxillary premolars were used for the study. The test samples were decoronated till the cementoenamel junction (CEJ) and proper cleaning and shaping was done with protaper niti files till the F3. Corresponding f3 protaper(Dentysply)gutta pecha cones were selected and obturated. The gutta-percha was removed till the depth of 4 mm from the coronal orifice with Gates Glidden (GG) drills for all the samples; then the samples were randomly divided into three different groups. Group I was restored with universal composite Z350XT, group II was restored with light curable glass ionomer cement (GIC), and group III was restored with miracle mix. The coronal buildup was done using compound supported matrix. The fracture resistance strength of all the specimen groups was tested under a universal testing machine. Results: The data of the study were statistically analyzed by one-way analysis of variance (ANOVA) and Bonferroni's comparison test. Results of the study showed that group I that was restored with the universal composite Z350XT showed much higher fracture resistance strength compared to the other two groups. Statistically significant difference was noted between group I and group II and also between group I and group III. Conclusion: It can be concluded that the core buildup done with composite offered better occlusal fracture resistance strength compared to light curable GIC and miracle mix. PMID:27011931

  8. Tension plate for treatment of olecranon fractures: new surgical technique and case series study

    PubMed Central

    Lukšic, Bruno; Juric, Ivo; Boschi, Vladimir; Pogorelic, Zenon; Bekavac, Josip

    2015-01-01

    Background Our aim was to determine the effectiveness of a new surgical technique for olecranon fractures using a tension plate (TP) designed by the operating surgeon. Methods We included patients with olecranon fractures treated between September 2010 and August 2013 in our study. Treatment involved a new implant and operative technique, which combined the most favourable characteristics of 2 frequently used methods, tension band wiring and plate osteosynthesis, while eliminating their shortcomings. The new method was based on the newly constructed implant. Results Twenty patients participated in our study. We obtained the following functional results with our TP: median flexion 147.5° (interquartile range [IQR] 130°–155°), median extension 135°/deficit 10° (IQR 135°–145°), median pronation 90° (IQR 81.3°–90°), median supination 90° (IQR 80°–90°). Implant-related complications were noted in 1 patient, and implants were removed in 3 patients. The mean functional Mayo elbow performance score was 94.8 (range 65–100). The removal of the implant was considerably less frequent in patients operated using the new method and implant than in patients operated using conventional methods at our institution (p < 0.001). Mean duration of follow-up was 8 months. Conclusion Our TP for the treatment of olecranon fractures is safe and effective. Functional results are very good, with significantly decreased postoperative inconveniences and need to remove the implant. Less osteosynthetic material was used for TP construction, but stability was preserved. PMID:25427338

  9. Risk of injury to vascular-nerve bundle after calcaneal fracture: comparison among three techniques

    PubMed Central

    Labronici, Pedro José; Reder, Vitor Rodrigues; de Araujo Marins Filho, Guilherme Ferreira; Pires, Robinson Esteves Santos; Fernandes, Hélio Jorge Alvachian; Mercadante, Marcelo Tomanik

    2016-01-01

    Objective To ascertain whether the number of screws or pins placed in the calcaneus might increase the risk of injury when three different techniques for treating calcaneal fractures. Method 126 radiographs of patients who suffered displaced calcaneal fractures were retrospectively analyzed. Three surgical techniques were analyzed on an interobserver basis: 31 radiographs of patients treated using plates that were not specific for the calcaneus, 48 using specific plates and 47 using an external fixator. The risk of injury to the anatomical structures in relation to each Kirschner wire or screw was determined using a graded system in accordance with the Licht classification. The total risk of injury to the anatomical structures through placement of more than one wire/screw was quantified using the additive law of probabilities for the product, for independent events. Results All of the models presented high explanatory power for the risk evaluated, since the coefficient of determination values (R2) were greater than 98.6 for all the models. Therefore, the set of variables studied explained more than 98.6% of the variations in the risks of injury to arteries, veins or nerves and can be classified as excellent models for prevention of injuries. Conclusion The risk of injury to arteries, veins or nerves is not defined by the total number of pins/screws. The region and the number of pins/screws in each region define and determine the best distribution of the risk. PMID:27069891

  10. Fracture Detection in Alluvial Fan Deposits Using Near-Surface Seismic Reflection Techniques

    NASA Astrophysics Data System (ADS)

    Black, R. A.; Miller, B.

    2012-12-01

    In this study we document the observation of probable extensive shallow vertical fracture systems in unprocessed 2-D source gathers from near-surface seismic reflection surveys conducted over unconsolidated materials in alluvial fans environments. Mapping of fracture and fault systems within the sedimentary sections at hydrocarbon exploration scales has become common practice. This is due to the advent of post-stack attribute analysis of 3-D seismic images worldwide. However, examples of fracture detection and imaging in the near-surface are currently lacking in the literature. In addition, examples of fracture detection and mapping in the pre-stack domain are also lacking. In this study, unprocessed seismic source gathers from very high-resolution reflection surveys over alluvial fan deposits in tectonically active areas appear to display distinct patterns of amplitude drop off, geometrically similar to patterns expected for vertical fracture systems. The patterns can also be extracted by attribute analysis using techniques such as envelope and coherency analyses. Simple standard processing steps such as trace editing, muting, and bandpass filtering enhance interpretability. The patterns appear to be consistent and spatially fixed in the subsurface from source location to source location. These are observed in areas of obvious recent local large-scale fault movement. Examples are given from two areas, eastern Queen Valley in California and eastern Fish Lake Valley in Nevada. The stratigraphic and sedimentation patterns are quite complicated in both areas, and sediment characteristics vary considerably between sites. The surface sediments in the Queen Valley case are, in general, much coarser with many more boulder-sized clasts in the shallow subsurface. The seismic source consisted of a 30-06 rifle fired downhole at a depth of 0.5m. While the boulders interfered with seismic source operations, the record quality was excellent. The alluvial materials, especially

  11. 3D hybrid tectono-stochastic modeling of naturally fractured reservoir: Application of finite element method and stochastic simulation technique

    NASA Astrophysics Data System (ADS)

    Gholizadeh Doonechaly, N.; Rahman, S. S.

    2012-05-01

    Simulation of naturally fractured reservoirs offers significant challenges due to the lack of a methodology that can utilize field data. To date several methods have been proposed by authors to characterize naturally fractured reservoirs. Among them is the unfolding/folding method which offers some degree of accuracy in estimating the probability of the existence of fractures in a reservoir. Also there are statistical approaches which integrate all levels of field data to simulate the fracture network. This approach, however, is dependent on the availability of data sources, such as seismic attributes, core descriptions, well logs, etc. which often make it difficult to obtain field wide. In this study a hybrid tectono-stochastic simulation is proposed to characterize a naturally fractured reservoir. A finite element based model is used to simulate the tectonic event of folding and unfolding of a geological structure. A nested neuro-stochastic technique is used to develop the inter-relationship between the data and at the same time it utilizes the sequential Gaussian approach to analyze field data along with fracture probability data. This approach has the ability to overcome commonly experienced discontinuity of the data in both horizontal and vertical directions. This hybrid technique is used to generate a discrete fracture network of a specific Australian gas reservoir, Palm Valley in the Northern Territory. Results of this study have significant benefit in accurately describing fluid flow simulation and well placement for maximal hydrocarbon recovery.

  12. Flexible Intramedullary Nailing of Pediatric Humeral Fractures: Indications, Techniques, and Tips.

    PubMed

    Kelly, Derek M

    2016-06-01

    Most proximal and diaphyseal pediatric humeral fractures can be treated successfully by closed means; however, certain patient factors or fracture characteristics may make surgical stabilization with flexible intramedullary nails (FIN) a better choice. Common indications for FIN of pediatric humeral fractures include unstable proximal-third fractures in children nearing skeletal maturity, unstable distal metaphyseal-diaphyseal junction fractures, shaft fractures in polytraumatized patients or patients with ipsilateral both-bone forearm fractures (floating elbow), and prophylactic stabilization of benign diaphyseal bone cysts or surgical stabilization of pathologic fractures. FIN can be safely inserted in an antegrade or retrograde manner depending on the fracture location and configuration. Careful dissection at the location of rod insertion can prevent iatrogenic nerve injuries. Rapid fracture union and return to full function can be expected in most cases. Implant prominence is the most common complication. PMID:27152902

  13. Distal humeral plating of an intramedullary nail periprosthetic fracture using a miss-a-nail technique: a case report

    PubMed Central

    Singh, Ravi; Corbett, Steven A

    2009-01-01

    The treatment of distal humeral periprosthetic fractures is not widely described in the literature. We present a difficult clinical scenario of a 72-year-old man who sustained a displaced distal humeral periprosthetic fracture about a Polarus Plus intramedullary nail. In this case, stable fixation was achieved using bicondylar Acumed Mayo congruent Plates using a miss-a-nail technique. Four months following the post operative period, the patient regained satisfactory range of movement with full function and no further complications up to 18 months post fixation. Treatment of such complex periprosthetic fractures is technically achievable and with potentially good results. PMID:19829846

  14. Deepest hypocentral distributions associated with stagnant slabs and penetrated slabs

    NASA Astrophysics Data System (ADS)

    Fukao, Y.; Obayashi, M.

    2013-12-01

    We constructed a new P-wave tomographic model of the mantle, GAP_P4, using more than ten millions of travel time data, including waveform-based differential travel times from ocean bottoms, to all of which the finite frequency kernels were applied in the inversion. Based on this model, we made a systematic survey for subducted slab images around the Circum Pacific. This survey revealed a progressive lateral variation of slab configuration along arc(s), where a subducted slab is in general in one or two of the following four stages: I. slab stagnant above the 660, II. slab penetrating the 660, III. slab trapped in the uppermost lower mantle (660 to ˜1000 km in depth), and IV. slab descending well into the deep lower mantle. The majority of the slab images are either at stage I or III. We interpret I to IV as the successive stages of slab subduction through the transition region with the 660 at the middle. There is a remarkable correlation of the slab configuration with the deepest shock hypocentral distribution. Subhorizontal distributions of deepest shocks are associated with stagnant slabs in the transition zone (slabs at stage I). Their focal depths are limited to shallower than ˜620 km. Steeply dipping deepest shock distributions are associated with penetrating slabs across the 660-km discontinuity or trapped slabs below it (slabs at stages II and III). Their focal depths extend well beyond ˜620 km. There are no cases of association of either a stagnant slab (at stage I) with subvertical distribution of deepest shocks or a trapped slab (at stage II or III) with their subhorizontal distribution. Only steeply dipping slabs appear to penetrate the 660 to be trapped in the uppermost lower mantle. The along-arc variations of stagnant-slab configuration and deepest shock distribution beneath the Bonin arc indicate a process of how the slab begins to penetrate the 660-km discontinuity after the slab stagnation. Those beneath the Java arc and Kermadec arc commonly

  15. An in situ high voltage electron microscopy technique for the study of deformation and fracture: In multilayered materials

    SciTech Connect

    Wall, M.A.; Barbee, T.W. Jr.; Weihs, T.P.

    1995-04-14

    A novel, in situ, high voltage electron microscopy technique for the direct observation of the micromechanisms of tensile deformation and fracture in nanostructured materials is detailed. This technique is particularly well suited for the dynamic observations of deformation and fracture in multilayered materials. The success of this type of in situ technique is highly dependent upon unique specimen preparation procedures and sample design, the importance thereof will be discussed. The initial observations discussed here are expected to aid in the understanding of the mechanical behavior of this new class of atomically engineered materials.

  16. Biomechanical evaluation of four different posterior screw and rod fixation techniques for the treatment of the odontoid fractures.

    PubMed

    Li, Lei; Liu, Wen-Fei; Jiang, Hong-Kun; Li, Yun-Peng

    2015-01-01

    Problems that screw cannot be inserted may occur in screw-rod fixation techniques such as Harms technique. We compared the biomechanical stability imparted to the C-2 vertebrae by four designed posterior screw and rod fixation techniques for the management of odontoid fractures. A three-dimensional finite element model of the odontoid fracture was established by subtracting several unit structures from the normal model from a healthy male volunteer. 4 different fixation techniques, shown as follows: ① C-1 lateral mass and C-2 pedicle screw fixation (Harms technique); ② C-1 lateral mass and unilateral C-2 pedicle screw fixation combined with ipsilateral laminar screw fixation; ③ Unilateral C-1lateral mass combined with ipsilateral C-1 posterior arch, and C-2 pedicle screw fixation; and ④ Unilateral C1 lateral mass screw connected with bilateral C2 pedicle screw fixation was performed on the odontoid fracture model. The model was validated for axial rotation, flexion, extension, lateral bending, and tension for 1.5 Nm. Changes in motion in flexion-extension, lateral bending, and axial rotation were calculated. The finite element model of the odontoid fracture was established in this paper. All of the four screw-rod techniques significantly decreased motion in flexion-extension, lateral bending, and axial rotation, as compared with the destabilized odontoid fracture complex (P<0.05). There was no statistically significant difference in stability among the four screw techniques. We concluded that the first three fixation techniques are recommended to be used as surgical intervention for odontoid fracture, while the last can be used as supplementary for the former three methods. PMID:26309508

  17. Biomechanical evaluation of four different posterior screw and rod fixation techniques for the treatment of the odontoid fractures

    PubMed Central

    Li, Lei; Liu, Wen-Fei; Jiang, Hong-Kun; Li, Yun-Peng

    2015-01-01

    Problems that screw cannot be inserted may occur in screw-rod fixation techniques such as Harms technique. We compared the biomechanical stability imparted to the C-2 vertebrae by four designed posterior screw and rod fixation techniques for the management of odontoid fractures. A three-dimensional finite element model of the odontoid fracture was established by subtracting several unit structures from the normal model from a healthy male volunteer. 4 different fixation techniques, shown as follows: ① C-1 lateral mass and C-2 pedicle screw fixation (Harms technique); ② C-1 lateral mass and unilateral C-2 pedicle screw fixation combined with ipsilateral laminar screw fixation; ③ Unilateral C-1lateral mass combined with ipsilateral C-1 posterior arch, and C-2 pedicle screw fixation; and ④ Unilateral C1 lateral mass screw connected with bilateral C2 pedicle screw fixation was performed on the odontoid fracture model. The model was validated for axial rotation, flexion, extension, lateral bending, and tension for 1.5 Nm. Changes in motion in flexion-extension, lateral bending, and axial rotation were calculated. The finite element model of the odontoid fracture was established in this paper. All of the four screw-rod techniques significantly decreased motion in flexion-extension, lateral bending, and axial rotation, as compared with the destabilized odontoid fracture complex (P<0.05). There was no statistically significant difference in stability among the four screw techniques. We concluded that the first three fixation techniques are recommended to be used as surgical intervention for odontoid fracture, while the last can be used as supplementary for the former three methods. PMID:26309508

  18. Plating osteosynthesis of mid-distal humeral shaft fractures: minimally invasive versus conventional open reduction technique

    PubMed Central

    Zeng, Bingfang; He, Xiaojian; Chen, Qi; Hu, Shundong

    2009-01-01

    Results of two methods, conventional open reduction–internal plating and minimally invasive plating osteosynthesis (MIPO), in the treatment of mid-distal humeral shaft fractures were compared. Thirty-three patients were retrospectively analysed and divided into two groups. Group A (n = 17) patients were treated by MIPO and group B (n = 16) by conventional plating. The mean operation time in group A was 92.35 ± 57.68 minutes and 103.12 ± 31.08 minutes in group B (P = 0.513). Iatrogenic radial nerve palsy in group A was 0% (0/17) and 31.3% in group B (5/16 (P = 0.012). The mean fracture union time in group A was 15.29 ± 4.01 weeks (range 8–24 weeks), and 21.25 ± 13.67 weeks (range 10–58 weeks) in group B (P = 0.095). The mean UCLA end-result score in group A was 34.76 ± 0.56 points (range 33–35), and 34.38 ± 1.41 points (range 30–35) in group B (P = 0.299). The mean MEPI in group A was 99.41 ± 2.43 points (range 90–100) and 99.69 ± 1.25 points (range 95–100) in group B (P = 0.687). When compared to the conventional plating techniques, MIPO offers advantages in terms of reduced incidence of iatrogenic radial nerve palsies and accelerated fracture union and a similar functional outcome with respect to shoulder and elbow function. PMID:19301000

  19. Closed reduction and K-wiring with the Kapandji technique for completely displaced pediatric distal radial fractures.

    PubMed

    Satish, Bhava R J; Vinodkumar, Muniramaiah; Suresh, Masilamani; Seetharam, Prasad Y; Jaikumar, Krishnaraj

    2014-09-01

    In completely displaced pediatric distal radial fractures, achieving satisfactory reduction with closed manipulation and maintenance of reduction with casting is difficult. Although the Kapandji technique of K-wiring is widely practiced for distal radial fracture fixation in adults, it is rarely used in pediatric acute fractures. Forty-six completely displaced distal radial fractures in children 7 to 14 years old were treated with closed reduction and K-wire fixation. One or 2 intrafocal K-wires were used to lever out and reduce the distal fragment's posterior and radial translation. One or 2 extrafocal K-wires were used to augment intrafocal fixation. Postoperative immobilization was enforced for 3 to 6 weeks (with a short arm plaster of Paris cast for the first half of the time and a removable wrist splint for the second half), after which time the K-wires were removed. Patients were followed for a minimum of 4 months. Mean patient age was 9.5 years. Near-anatomical reduction was achieved easily with the intrafocal leverage technique in all fractures. Mean procedure time for K-wiring was 7 minutes. On follow-up, there was no loss of reduction; remanipulation was not performed in any case. There were no pin-related complications. All fractures healed, and full function of the wrist and forearm was achieved in every case. The Kapandji K-wire technique consistently achieves easy and near-anatomical closed reduction by a leverage reduction method in completely displaced pediatric distal radial fractures. Reduction is maintained throughout the fracture-healing period. The casting duration can be reduced without loss of reduction, and good functional results can be obtained. PMID:25350624

  20. Fracture toughness of the nickel-alumina laminates by digital image-correlation technique

    NASA Astrophysics Data System (ADS)

    Mekky, Waleed

    The purpose of this work is to implement the digital image correlation technique (DIC) in composite laminate fracture testing. The latter involves measuring the crack opening displacement (COD) during stable crack propagation and characterizing the strain development in a constrained nickel layer under applied loading. The major challenge to measure the COD of alternated metal/ceramic layers is the elastic-mismatch effect. This leads to oscillating COD measurement. Smoothing the result with built-in modules of commercial software leads to a loss of data accuracy. A least-squares fitting routine for the data output gave acceptable COD profiles. The behavior of a single Ni ligament sandwiched between two Al2O3 layers was determined for two Ni thicknesses (0.125 and 0.25mm). Modeling of the behavior via a modified Bridgman approach for rectangular cross section samples, proved limited as different mechanisms are operating. Nevertheless, the behavior is however captured to a point, but the model underestimates the results vis a vis experimental ones. The fracture-resistance curves for Nickel/Alumina laminates were developed experimentally and modeled via LEFM using the weight function approach and utilizing single-ligament-, and COD-, data. The crack-tip toughness was found to increase with Ni layer thickness due to crack-tip-shielding. The crack-initiation-toughness was estimated from the stress field and the crack-opening-displacement of the main crack.

  1. A simple new technique for the removal of fractured femoral stems: a case report

    PubMed Central

    2014-01-01

    Introduction The removal of broken femoral stems has become a major issue in revision surgery, and is a technically difficult and time-consuming procedure. Case presentation We present a case of a fracture of a cementless long femoral stem in a 65-year-old, white Caucasian man. The distal part was removed with a special longitudinal osteotomy through the anterior cortex extending distally for 10cm. It was then followed by a transversal osteotomy 2cm below the tip of the femoral stump to allow enough space for two locking pliers. Simultaneously using a lamina spreader on the distal part, the broken stem was extracted while hammering on two locking pliers. Conclusions We developed a simple and easy technique for the removal of a broken femoral stem that can be applied to all kinds of femoral stems and intramedullary nails regardless of their cross section. We used ordinary surgical instruments and spared the remaining bone stock. PMID:24886067

  2. Multiscale organization of joints and faults in a fractured reservoir revealed by geostatistical, multifractal and wavelet techniques

    SciTech Connect

    Castaing, C.; Genter, A.; Ouillon, G.

    1995-08-01

    Datasets of the geometry of fracture systems were analysed at various scales in the western Arabian sedimentary platform by means of geostatistical, multifractal, and anisotropic-wavelet techniques. The investigations covered a wide range of scales, from regional to outcrops in a well-exposed area, and were based on field mapping of fractures, and the interpretation and digitizing of fracture patterns on aerial photographs and satellite images. As a first step, fracture data sets were used to examine the direction, size, spacing and density systematics, and the variability in these quantities with space and scale. Secondly, a multifractal analysis was carried out, which consists in estimating the moments of the spatial distribution of fractures at different resolutions. This global multifractal method was complemented by a local wavelet analysis, using a new anisotropic technique tailored to linear structures. For a map with a given scale of detail, this procedure permits to define integrated fracture patterns and their associated directions at a more regional scale. The main result of this combined approach is that fracturing is not a self-similar process from the centimeter scale up to the one-million-kilometer scale. Spatial distribution of faults appears as being highly controlled by the thickness of the different rheological layers that constitute the crust. A proceeding for upscaling fracture systems in sedimentary reservoirs can be proposed, based on (i) a power law for joint-length distribution, (ii) characteristic joint spacing depending on the critical sedimentary units, and (iii) fractal fault geometry for faults larger than the whole thickness of the sedimentary basin.

  3. Cordilleran slab windows

    SciTech Connect

    Thorkelson, D.J.; Taylor, R.P. )

    1989-09-01

    The geometry and geologic implications of subducted spreading ridges are topics that have bedeviled earth scientists ever since the recognition of plate tectonics. As a consequence of subduction of the Kula-Farallon and East Pacific rises, slab windows formed and migrated beneath the North American Cordillera. The probable shape and extent of these windows, which represent the asthenosphere-filled gaps between two separating, subducting oceanic plates, are depicted from the Late Cretaceous to the present. Possible effects of the existence and migration of slab windows on the Cordillera at various times include cessation of arc volcanism and replacement by rift or plate-edge volcanism; lithospheric uplift, attenuation, and extension; and increased intensity of compressional tectonism. Eocene extensional tectonism and alkaline magmatism in southern British Columbia and the northwestern United States were facilitated by slab-window development.

  4. A Comparison of Open and Percutaneous Techniques in the Operative Fixation of Spinal Fractures Associated with Ankylosing Spinal Disorders

    PubMed Central

    Daffner, Scott D.; Obafemi-Afolabi, Abimbola; Gelb, Daniel; Ludwig, Steven; Emery, Sanford E.; France, John C.

    2016-01-01

    Background The operative care of patients with ankylosing spinal conditions such as ankylosing spondylitis (AS) and diffuse idiopathic skeletal hyperostosis (DISH) after a spine fracture is not well represented in the literature. This work seeks to determine the effect of minimally invasive techniques on patients with spinal fractures and ankylosing spinal conditions through a retrospective case-control analysis. Methods The operative logs from 1996-2013 of seven fellowship-trained spine surgeons from two academic, Level I trauma centers were reviewed for cases of operatively treated thoracic and lumbar spinal fractures in patients with ankylosing spinal disorders. Results A total of 38 patients with an ankylosing spinal condition and a spinal fracture were identified. The minimally invasive group demonstrated a statistically significant decrease in estimated blood loss, operative time, and need for transfusion when compared to either the hybrid or open group. There was no difference between the three subgroups in overall hospital stay or mortality. Conclusions Patients with ankylosing spinal conditions present unique challenges for operative fixation of spinal fractures. Minimally invasive techniques for internal fixation offer less blood loss, operative time, and need for transfusion compared to traditional techniques; however, no difference in hospital stay or mortality was reflected in this series of patients. Level of Evidence: 4. Clinical Relevance Ankylosing spinal disorders are increasingly common in an aging population. PMID:27441181

  5. Cardiopulmonary resuscitation (CPR)-related posterior rib fractures in neonates and infants following recommended changes in CPR techniques.

    PubMed

    Franke, I; Pingen, A; Schiffmann, H; Vogel, M; Vlajnic, D; Ganschow, R; Born, M

    2014-07-01

    Posterior rib fractures are highly indicative of non-accidental trauma (NAT) in infants. Since 2000, the "two-thumbs" technique for cardiopulmonary resuscitation (CPR) of newborns and infants has been recommended by the American Heart Association (AHA). This technique is similar to the grip on an infant's thorax while shaking. Is it possible that posterior rib fractures in newborns and infants could be caused by the "two-thumbs" technique? Using computerized databases from three German children's hospitals, we identified all infants less than 12 months old who underwent professional CPR within a 10-year period. We included all infants with anterior-posterior chest radiographs taken after CPR. Exclusion criteria were sternotomy, osteopenia, various other bone diseases and NAT. The radiographs were independently reviewed by the Chief of Pediatric Radiology (MB) and a Senior Pediatrician, Head of the local Child Protection Team (IF). Eighty infants with 546 chest radiographs were identified, and 50 of those infants underwent CPR immediately after birth. Data concerning the length of CPR was available for 41 infants. The mean length of CPR was 11min (range: 1-180min, median: 3min). On average, there were seven radiographs per infant. A total of 39 infants had a follow-up radiograph after at least 10 days. No rib fracture was visible on any chest X-ray. The results of this study suggest rib fracture after the use of the "two-thumbs" CPR technique is uncommon. Thus, there should be careful consideration of abuse when these fractures are identified, regardless of whether CPR was performed and what technique used. The discovery of rib fractures in an infant who has undergone CPR without underlying bone disease or major trauma warrants a full child protection investigation. PMID:24636360

  6. Buoyancy, bending, and seismic visibility in deep slab stagnation

    NASA Astrophysics Data System (ADS)

    Bina, Craig R.; Kawakatsu, Hitoshi; Suetsugu, D.; Bina, C.; Inoue, T.; Wiens, D.; Jellinek, M.

    2010-11-01

    The petrological consequences of deep subhorizontal deflection ("stagnation") of subducting slabs should affect both apparent seismic velocity structures and slab morphology. We construct kinematic thermal models of stagnant slabs and perform thermodynamic modeling of the consequent perturbation of high-pressure phase transitions in mantle minerals, focusing upon Japan as our study area. We calculate associated thermo-petrological buoyancy forces and bending moments which (along with other factors such as viscosity variations and rollback dynamics) may contribute to slab deformation. We consider effects of variations in depth of stagnation, post-stagnation dip angle, phase transition sharpness, transition triplication due to multiple intersection of geotherms with phase boundaries, and potential persistence of metastable phases due to kinetic hindrance. We also estimate seismic velocity anomalies, as might be imaged by seismic tomography, and corresponding seismic velocity gradients, as might be imaged by receiver-function analysis. We find that buoyant bending moment gradients of petrological origin at the base of the transition zone may contribute to slab stagnation. Such buoyancy forces vary with the depth at which stagnation occurs, so that slabs may seek an equilibrium slab stagnation depth. Metastable phase bending moment gradients further enhance slab stagnation, but they thermally decay after ∱/4600•700 km of horizontal travel, potentially allowing stagnant slabs to descend into the lower mantle. Stagnant slabs superimpose zones of negative velocity gradient onto a depressed 660-km seismic discontinuity, affecting the seismological visibility of such features. Seismologically resolvable details should depend upon both stagnation depth and the nature of the imaging technique (travel-time tomography vs. boundary-interaction phases). While seismic tomography appears to yield images of stagnant slabs, discontinuity topography beneath Japan resolved by

  7. Investigation of temperature dependence of fracture toughness in high-dose HT9 steel using small-specimen reuse technique

    SciTech Connect

    Baek, Jong-Hyuk; Byun, Thak Sang; Maloy, S; Toloczko, M

    2014-01-01

    The temperature dependence of fracture toughness in HT9 steel irradiated to 3 145 dpa at 380 503 C was investigated using miniature three-point bend (TPB) fracture specimens. A miniature-specimen reuse technique has been established: the tested halves of subsize Charpy impact specimens with dimensions of 27 mm 3mm 4 mm were reused for this fracture test campaign by cutting a notch with a diamond-saw in the middle of each half, and by fatigue-precracking to generate a sharp crack tip. It was confirmed that the fracture toughness of HT9 steel in the dose range depends more strongly on the irradiation temperature than the irradiation dose. At an irradiation temperature <430 C, the fracture toughness of irradiated HT9 increased with the test temperature, reached an upper shelf of 180 200 MPa ffiffiffiffiffi m p at 350 450 C, and then decreased with the test temperature. At an irradiation temperatureP430 C, the fracture toughness was nearly unchanged up to about 450 C and decreased slowly with test temperatures in a higher temperature range. Such a rather monotonic test temperature dependence after high-temperature irradiation is similar to that observed for an archive material generally showing a higher degree of toughness. A brittle fracture without stable crack growth occurred in only a few specimens with relatively lower irradiation and test temperatures. In this discussion, these TPB fracture toughness data are compared with previously published data from 12.7 mm diameter disc compact tension (DCT) specimens.

  8. Investigation of temperature dependence of fracture toughness in high-dose HT9 steel using small-specimen reuse technique

    SciTech Connect

    Baek, Jong-Hyuk; Byun, Thak Sang; Maloy, Stuart A.; Toloczko, Mychailo B.

    2014-01-01

    The temperature dependence of fracture toughness in HT9 steel irradiated to 3–145 dpa at 380–503 degrees*C was investigated using miniature three-point bend (TPB) fracture specimens. A miniature-specimen reuse technique has been established: the tested halves of subsize Charpy impact specimens with dimensions of 27 mm *3mm* 4 mm were reused for this fracture test campaign by cutting a notch with a diamond-saw in the middle of each half, and by fatigue-precracking to generate a sharp crack tip. It was confirmed that the fracture toughness of HT9 steel in the dose range depends more strongly on the irradiation temperature than the irradiation dose. At an irradiation temperature <430 *degreesC, the fracture toughness of irradiated HT9 increased with the test temperature, reached an upper shelf of 180—200 MPa*m^.5 at 350–450 degrees*C, and then decreased with the test temperature. At an irradiation temperature >430 degrees*C, the fracture toughness was nearly unchanged up to about 450 *degreesC and decreased slowly with test temperatures in a higher temperature range. Such a rather monotonic test temperature dependence after high-temperature irradiation is similar to that observed for an archive material generally showing a higher degree of toughness. A brittle fracture without stable crack growth occurred in only a few specimens with relatively lower irradiation and test temperatures. In this discussion, these TPB fracture toughness data are compared with previously published data from 12.7 mm diameter disc compact tension (DCT) specimens.

  9. Investigation of temperature dependence of fracture toughness in high-dose HT9 steel using small-specimen reuse technique

    NASA Astrophysics Data System (ADS)

    Baek, Jong-Hyuk; Byun, Thak Sang; Maloy, Start A.; Toloczko, Mychailo B.

    2014-01-01

    The temperature dependence of fracture toughness in HT9 steel irradiated to 3-145 dpa at 380-503 °C was investigated using miniature three-point bend (TPB) fracture specimens. A miniature-specimen reuse technique has been established: the tested halves of subsize Charpy impact specimens with dimensions of 27 mm × 3 mm × 4 mm were reused for this fracture test campaign by cutting a notch with a diamond-saw in the middle of each half, and by fatigue-precracking to generate a sharp crack tip. It was confirmed that the fracture toughness of HT9 steel in the dose range depends more strongly on the irradiation temperature than the irradiation dose. At an irradiation temperature <430 °C, the fracture toughness of irradiated HT9 increased with the test temperature, reached an upper shelf of 180-200 MPa √{m} at 350-450 °C, and then decreased with the test temperature. At an irradiation temperature ⩾430 °C, the fracture toughness was nearly unchanged up to about 450 °C and decreased slowly with test temperatures in a higher temperature range. Such a rather monotonic test temperature dependence after high-temperature irradiation is similar to that observed for an archive material generally showing a higher degree of toughness. A brittle fracture without stable crack growth occurred in only a few specimens with relatively lower irradiation and test temperatures. In this discussion, these TPB fracture toughness data are compared with previously published data from 12.7 mm diameter disc compact tension (DCT) specimens.

  10. Slab Leaf Bowls

    ERIC Educational Resources Information Center

    Suitor, Cheryl

    2012-01-01

    In science class, fourth graders investigate the structure of plants and leaves from trees and how the process of photosynthesis turns sunlight into sugar proteins. In this article, the author fuses art and science for a creative and successful clay slab project in her elementary art classroom. (Contains 1 online resource.)

  11. Fracture density in the deep subsurface: Techniques with application to Point Arguello oil field

    SciTech Connect

    Narr, W. )

    1991-08-01

    Because Monterey Formation reservoirs rely on fractures (joints) for permeability, quantitative information on fracture spacing is important to exploration strategies and for understanding reservoir behavior. Density of joints in cores of four wells from the Point Arguello reservoir has been determined with a new, probability-based method, and these subsurface joint densities are compared with joint densities is the fracture-spacing index, which is the slope of the trend of layer thickness to joint spacing. In core and at outcrop, the only lithologic control on joint density is between nonjointed mudstone and harder (more brittle), jointed rocks. Within each well, the fracture-spacing index is the same for all hard rocks (though it varies between wells). In the reservoir, joint density relates to structural position. At outcrops in various structural settings, the fracture-spacing index is the same (approximately 1.29) in chert, dolostone, and porcelanite and siliceous shale. These rocks may be saturated with joints, so that differences in brittle strain due to local structural variations have been overwhelmed as joints continued to form during unroofing of these strata. Chert looks more fractured than other lithologies because of thin bedding. Fracture-spacing index is used to compute such parameters as fracture porosity and volume of fractures that directly contact the well bore. These parameters may be important when trying to model the behavior of a petroleum reservoir, or when trying to assess the feasibility of strongly deviating wells to improve the performance of a fracture reservoir.

  12. An Effective and Feasible Method, “Hammering Technique,” for Percutaneous Fixation of Anterior Column Acetabular Fracture

    PubMed Central

    Zhang, Lihai; Zhang, Wei; Li, Tongtong; Li, Jiantao; Chen, Hua

    2016-01-01

    Objective. The objective of this study was to evaluate the effectiveness and advantages of percutaneous fixation of anterior column acetabular fracture with “hammering technique.” Materials and Methods. We retrospectively reviewed 16 patients with percutaneous fixation of anterior column acetabular fracture with “hammering technique.” There were 11 males and 5 females with an average age of 38.88 years (range: 24–54 years) in our study. Our study included 7 nondisplaced fractures, 6 mild displaced fractures (<2 mm), and 5 displaced fractures (>2 mm). The mean time from injury to surgery was 4.5 days (range: 2–7 days). Results. The average of operation time was 27.56 minutes (range: 15–45 minutes), and the mean blood loss was 55.28 mL (range: 15–100 mL). The mean fluoroscopic time was 54.78 seconds (range: 40–77 seconds). The first pass of the guide wire was acceptable without cortical perforation or intra-articular perforation in 88.89% (16/18) of the procedures, and the second attempt was in 11.11% (2/18). Conclusion. Our study suggested that percutaneous fixation of anterior column acetabular fracture with “hammering technique” acquired satisfying surgical and clinical outcomes. It may be an alternative satisfying treatment for percutaneous fixation of anterior column acetabular fracture by 2D fluoroscopy using a C-arm with less fluoroscopic time. PMID:27493962

  13. A prospective study of a modified pin-in-plaster technique for treatment of fractures of the distal radius

    PubMed Central

    Mirghasemi, S. A.; Rashidinia, S.; Sadeghi, M. S.; Talebizadeh, M.; Rahimi, N.

    2015-01-01

    Objectives There are various pin-in-plaster methods for treating fractures of the distal radius. The purpose of this study is to introduce a modified technique of ‘pin in plaster’. Methods Fifty-four patients with fractures of the distal radius were followed for one year post-operatively. Patients were excluded if they had type B fractures according to AO classification, multiple injuries or pathological fractures, and were treated more than seven days after injury. Range of movement and functional results were evaluated at three and six months and one and two years post-operatively. Radiographic parameters including radial inclination, tilt, and height, were measured pre- and post-operatively. Results The average radial tilt was 10.6° of volar flexion and radial height was 10.2 mm at the sixth month post-operatively. Three cases of pin tract infection were recorded, all of which were treated successfully with oral antibiotics. There were no cases of pin loosening. A total of 73 patients underwent surgery, and three cases of radial nerve irritation were recorded at the time of cast removal. All radial nerve palsies resolved at the six-month follow-up. There were no cases of median nerve compression or carpal tunnel syndrome, and no cases of tendon injury. Conclusion Our modified technique is effective to restore anatomic congruity and maintain reduction in fractures of the distal radius. Cite this article: Bone Joint Res 2015;4:176–180 PMID:26541833

  14. Alternative techniques in trochanteric hip fracture surgery. Clinical and biomechanical studies on the Medoff sliding plate and the Twin hook.

    PubMed

    Olsson, O

    2000-10-01

    In allowing compression along the femoral shaft (uniaxial dynamization) and optional compression along the femoral neck (biaxial dynamization), the Medoff sliding plate (MSP) represents a new principle in the fixation of trochanteric hip fractures. The Twin hook with 2 apical hooks was designed as an alternative to the lag screw. In 3 prospective consecutive case series and 1 prospective randomized study together comprising 342 trochanteric fractures, these alternative techniques were investigated. 3 postoperative fixation failures occurred in the unstable intertrochanteric fractures treated with biaxial dynamization with the MSP (n = 194), and 5 in those treated with the sliding hip screw (n = 62) (p = 0.04). A mean femoral shortening of 15 mm with the MSP and 11 mm with the sliding hip screw was found (p = 0.03). More medialization of the femoral shaft occurred with the sliding hip screw (26%) than with the MSP (12%) in patients with marked femoral shortening (p = 0.03). 3 postoperative fixation failures occurred in subtrochanteric fractures treated with uniaxial dynamization (n = 29) and 2 in those treated with biaxial dynamization (n = 19). Medialization of the femoral shaft occurred in 9 of the 19 biaxially dynamized fractures. The Twin hook was used in 50 patients and appeared to provide similar fixation stability as the lag screw. Biomechanical tests confirmed improved stress transmission over the fracture area with the MSP compared to the sliding hip screw in intertrochanteric fractures, and similar fixation stability with the MSP and the Intramedullary Hip Screw in subtrochanteric fractures. In axial and torsional loading, the Twin hook demonstrated gradually increasing resistance to migration. With the lag screw, the peak load was higher, but after migration with failure of the support by the threads, the loads were similar. Biaxial dynamization with the MSP appears to control fracture impaction effectively and minimizes the rate of postoperative fixation

  15. Development of Reservoir Characterization Techniques and Production Models for Exploiting Naturally Fractured Reservoirs

    SciTech Connect

    Wiggins, Michael L; Brown, Raymon L.; Civan, Faruk; Hughes, Richard G.

    2002-10-08

    During this reporting period, research was continued on characterizing and modeling the behavior of naturally fractured reservoir systems. This report proposed a model to relate the seismic response to production data to determine crack spacing and aperture, provided details of tests of proposed models to obtain fracture properties from conventional well logs with actual field data, and verification of the naturally fractured reservoir simulator developed in this project.

  16. Slab melting versus slab dehydration in subduction-zone magmatism

    PubMed Central

    Mibe, Kenji; Kawamoto, Tatsuhiko; Matsukage, Kyoko N.; Fei, Yingwei; Ono, Shigeaki

    2011-01-01

    The second critical endpoint in the basalt-H2O system was directly determined by a high-pressure and high-temperature X-ray radiography technique. We found that the second critical endpoint occurs at around 3.4 GPa and 770 °C (corresponding to a depth of approximately 100 km in a subducting slab), which is much shallower than the previously estimated conditions. Our results indicate that the melting temperature of the subducting oceanic crust can no longer be defined beyond this critical condition and that the fluid released from subducting oceanic crust at depths greater than 100 km under volcanic arcs is supercritical fluid rather than aqueous fluid and/or hydrous melts. The position of the second critical endpoint explains why there is a limitation to the slab depth at which adakitic magmas are produced, as well as the origin of across-arc geochemical variations of trace elements in volcanic rocks in subduction zones. PMID:21536910

  17. Slab melting versus slab dehydration in subduction-zone magmatism.

    PubMed

    Mibe, Kenji; Kawamoto, Tatsuhiko; Matsukage, Kyoko N; Fei, Yingwei; Ono, Shigeaki

    2011-05-17

    The second critical endpoint in the basalt-H(2)O system was directly determined by a high-pressure and high-temperature X-ray radiography technique. We found that the second critical endpoint occurs at around 3.4 GPa and 770 °C (corresponding to a depth of approximately 100 km in a subducting slab), which is much shallower than the previously estimated conditions. Our results indicate that the melting temperature of the subducting oceanic crust can no longer be defined beyond this critical condition and that the fluid released from subducting oceanic crust at depths greater than 100 km under volcanic arcs is supercritical fluid rather than aqueous fluid and/or hydrous melts. The position of the second critical endpoint explains why there is a limitation to the slab depth at which adakitic magmas are produced, as well as the origin of across-arc geochemical variations of trace elements in volcanic rocks in subduction zones. PMID:21536910

  18. Olecranon Fractures.

    PubMed

    Brolin, Tyler J; Throckmorton, Thomas

    2015-11-01

    Olecranon fractures are common upper extremity injuries, with all but nondisplaced fractures treated surgically. There has been a recent shift in the surgical management of these fractures from tension band wiring to locking plate fixation and intramedullary nailing; however, this comes with increased implant cost. Although most patients can expect good outcomes after these various techniques, there is little information to guide a surgeon's treatment plan. This article reviews the epidemiology, classification, treatment, and outcomes of olecranon fractures. PMID:26498547

  19. Technique of Open Reduction and Internal Fixation of Comminuted Proximal Humerus Fractures With Allograft Femoral Head Metaphyseal Reconstruction.

    PubMed

    Parada, Stephen A; Makani, Amun; Stadecker, Monica J; Warner, Jon J P

    2015-10-01

    Proximal humerus fractures are common injuries that can require operative treatment. Different operative techniques are available, but the hallmark of fixation for 3- and 4-part fractures is a locking-plate-and-screw construct. Despite advances in this technology, obtaining anatomical reduction and fracture union can be difficult, and complications (eg, need for revision) are not uncommon. These issues can be addressed by augmenting the fixation with an endosteally placed fibular allograft. Although biomechanical and clinical results have been good, the technique can lead to difficulties in future revision to arthroplasty, a common consequence of failed open reduction and internal fixation. The technique described, an alternative to placing a long endosteal bone graft, uses a trapezoidal, individually sized pedestal of allograft femoral head to facilitate the reduction and healing of the humeral head and tuberosity fragments in a displaced 3- or 4-part fracture of the proximal humerus. It can be easily incorporated with any plate-and-screw construct and does not necessitate placing more than 1 cm of bone into the humeral intramedullary canal, limiting the negative effects on any future revision to arthroplasty. PMID:26447409

  20. Measuring snow properties relevant to slab avalanche release

    NASA Astrophysics Data System (ADS)

    Reuter, Benjamin; Proksch, Martin; Löwe, Henning; van Herwijnen, Alec; Schweizer, Jürg

    2014-05-01

    The release of a slab avalanche is preceded by a sequence of fractures. The main material properties relevant for the fracture processes are the specific fracture energy of the weak layer, as also the elastic modulus and the density of the overlying slab layers. The snow micro-penetrometer (SMP) is the method of choice for snow stratigraphy measurements in the field with high resolution. Recent advances in signal processing allow us to derive the most needed material properties to model the fracture behaviour of snow. On a smaller scale, the three dimensional structure of snow samples is obtained from snow micro-tomography (CT) providing snow density directly. By modelling the mechanical behaviour of the ice matrix the elastic properties of the snow sample can be calculated. At the macro-scale, fracture mechanical field tests with particle tracking velocimetry (PTV) allow observing the in-situ fracture behaviour. Specific fracture energy and slab stiffness are derived from PTV measurement by fitting an analytical beam equation to the observed deformation field. Over the past years we were able to generate two datasets of overlapping SMP and CT as well as SMP and PTV measurements. SMP measurements and micro-tomography of snow samples show that snow density is well reproduced with current SMP signal processing algorithms. Also the specific fracture energy as derived from the SMP signal is in agreement with PTV results. The effective modulus, however, being the most sensitive parameter in fracture covers three orders of magnitude depending on measurement method. The present work discusses observed similarities and differences arising from measurement methods, theoretical assumptions and process scales. Reliable methods to determine the parameters describing the fracture process are key to snow instability modelling based on either snow cover simulations or field measurements. Preliminary modelling results from ongoing spatial variability studies illustrate the

  1. The chopstick-noodle twist: an easy technique of percutaneous patellar fixation in minimally displaced patellar fractures.

    PubMed

    Muzaffar, Nasir; Ahmad, Nawaz; Ahmad, Aejaz; Ahmad, Nissar

    2012-01-01

    We report six cases of minimally displaced two-part patellar fractures with skin injury over the patella that were treated with percutaneous K wire fixation and compression applied using stainless steel (SS) wire. This technique makes it possible to perform early operative treatment in cases where unhealthy skin is not amenable to conventional tension band wiring. The technique employs two K wires inserted through the two fracture fragments under local or regional anaesthesia. They are then compressed using simple SS wire knots at the two ends - making it look like noodles at the end of two chopsticks. The fixation is subsequently augmented with a cylindrical plaster-of-Paris cast. The technique is simple, cheap and does not cause soft tissue injury. PMID:22290109

  2. Long-bone fracture detection in digital X-ray images based on digital-geometric techniques.

    PubMed

    Bandyopadhyay, Oishila; Biswas, Arindam; Bhattacharya, Bhargab B

    2016-01-01

    Automated fracture detection is an essential part of a computer-aided tele-medicine system. In this paper, we have proposed a unified technique for the detection and evaluation of orthopaedic fractures in long-bone digital X-ray image. We have also developed a software tool that can be conveniently used by paramedics or specialist doctors. The proposed tool first segments the bone region of an input digital X-ray image from its surrounding flesh region and then generates the bone-contour using an adaptive thresholding approach. Next, it performs unsupervised correction of bone-contour discontinuities that might have been generated because of segmentation errors, and finally detects the presence of fracture in the bone. Moreover, the method can also localize the line-of-break for easy visualization of the fracture, identify its orientation, and assess the extent of damage in the bone. Several concepts from digital geometry such as relaxed straightness and concavity index are utilized to correct contour imperfections, and to detect fracture locations and type. Experiments on a database of several long-bone digital X-ray images show satisfactory results. PMID:26477855

  3. Visualization of Fluid Flow through in a Rough-Walled Fracture Using micro-PIV Technique

    NASA Astrophysics Data System (ADS)

    Lee, S.; Yeo, I.; Song, H.; Yoo, J.; Lee, K.

    2010-12-01

    Fluid flow in rough-walled rock fractures have been described by the cubic law and the Reynolds equation which are derived from Navier-Stokes equation. They are based on the assumption of a laminar flow, and basically state that fluid flux is proportional to cube of the aperture of the channel, which yields an ideal parabolic velocity profile across the channel. However, it has been reported that even for low Reynolds numbers (Re), there are discrepancies between analytical/numerical works and experiments. It is questioned whether these assumptions are satisfied in real rough-walled fractures even for Re<1. In order to examine those assumptions, micro-PIV (particle image velocimetry) was introduced, which allowed for direct and microscopic observation of fluid flow in rough-walled fractures. Both surfaces of a rough-walled fracture were scanned, and were then duplicated on acrylics using CNC modeling machine, which formed a rough-walled acrylic fracture with and 450 micrometer average aperture. Deionized water, mixed with 2 micrometer size of fluorescent particle, was injected into the rough-walled acrylic fracture at Re = 0.01, 0.025, 0.05, and 0.10. Velocity vectors were calculated by analyzing relative movement of particles between snap shots. Fluid flow features were primarily monitored at the five representative spots of fracture roughness. As a result, it was found that the laminar flow prevails over the fracture. For Re<1, the velocity profile was highly dependent on fracture roughness. The development of dead spots at which flow velocity was almost zero was remarkable in the regions where apertures change rapidly, which significantly reduces the channel that actually contributes to fluid flow: hydraulic aperture. Further quantitative analysis is in progress to examine whether the cubic law-based analytical solutions are effective for the quantification of fluid flow through rough-walled fractures.

  4. Carbon dioxide slab laser

    SciTech Connect

    Tulip, J.

    1988-01-12

    A gas slab laser is described comprising: first and second elongated electrodes each including a planar light reflecting surface disposed so as to form a light guide only in a plane perpendicular to the planar surface and to define a gas discharge gap therebetween; a laser gas disposed in the gap; and means for applying a radio frequency current between the first and second electrodes to establish a laser-exciting discharge in the laser gas.

  5. Least Possible Fixation Techniques of 4-Part Valgus Impacted Fractures of the Proximal Humerus: A Systematic Review

    PubMed Central

    Panagopoulos, Andreas; Tatani, Irini; Ntourantonis, Dimitrios; Seferlis, Ioannis; Kouzelis, Antonis; Tyllianakis, Minos

    2016-01-01

    The valgus-impacted (VI) 4-part fractures are a subset of fractures of the proximal humerus with a unique anatomic configuration characterized by a relatively lower incidence of avascular necrosis after operative intervention. We systematically reviewed clinical studies assessing the benefits and harms of least possible fixation techniques (LPFT) for this unique fracture type. Such information would be potentially helpful in developing an evidence-based approach in the management of these complex injuries. We performed analytic searches of PubMed, Embase, Web of Science, Google Scholar and the Cochrane Library, restricting it to the years 1991-2014. Included studies had to describe outcomes and complications after primary osteosynthesis with any type of LPFT apart from plate-screws and intramedullary nailing. Eligibility criteria were also included English language, more than 5 cases, minimum follow up of one year and report of clinical outcome using at least one relevant score (Constant, Neer or ASES). Based on 292 database hits we identified 12 eligible studies including 190 four-part valgus impacted fractures in 188 patients. All eligible studies were case series composed of min 8 to max 45 patients per study. The gender distribution was 60% (112) female and 40% (76) male. The average age of the patients at the time of injury was 54.5 years. In 8/12 studies an open reduction was used for fracture fixation using different surgical techniques including KW, cerclage wires, cannulated screws and osteosutures. Closed reduction and percutaneous fixation was used in 4 studies. Mean follow-up time ranged from 24 to 69 months. A good functional outcome (constant score >80) was reported in 9/12 studies. The most common complication was avascular necrosis of the humeral head with an overall incidence of 11% (range, 0-26.3%). Total avascular necrosis (AVN) was found in 15/188 patients (7.9%) and was more common in percutaneous techniques and partial AVN in 6/188 (3

  6. Modified Labial Button Technique for Maintaining Occlusion After Caudal Mandibular Fracture/Temporomandibular Joint Luxation in the Cat.

    PubMed

    Goodman, Alice E; Carmichael, Daniel T

    2016-03-01

    Maxillofacial trauma in cats often results in mandibular symphyseal separation in addition to injuries of the caudal mandible and/or temporomandibular joint (TMJ). Caudal mandibular and TMJ injuries are difficult to access and stabilize using direct fixation techniques, thus indirect fixation is commonly employed. The immediate goals of fixation include stabilization for return to normal occlusion and function with the long-term objective of bony union. Indirect fixation techniques commonly used for stabilization of caudal mandibular and temporomandibular joint fracture/luxation include maxillomandibular fixation (MMF) with acrylic composite, interarcade wiring, tape muzzles, and the bignathic encircling and retaining device (BEARD) technique. This article introduces a modification of the previously described "labial reverse suture through buttons" technique used by Koestlin et al and the "labial locking with buttons" technique by Rocha et al. In cases with minimally displaced subcondylar and pericondylar fractures without joint involvement, the labial button technique can provide sufficient stabilization for healing. Advantages of the modified labial button technique include ease of application, noninvasive nature, and use of readily available materials. The construct can remain in place for a variable of amount of time, depending on its intended purpose. It serves as an alternative to the tape muzzle, which is rarely tolerated by cats. This technique can be easily used in conjunction with other maxillomandibular repairs, such as cerclage wire fixation of mandibular symphyseal separation. The purpose of this article is to demonstrate a modified labial button technique for maintaining occlusion of feline caudal mandibular fractures/TMJ luxations in a step-by-step fashion. PMID:27487655

  7. Preliminary results from osteosynthesis using Ender nails by means of a percutaneous technique, in humeral diaphysis fractures in adults☆

    PubMed Central

    Godinho, Glaydson Gomes; França, Flávio de Oliveira; Freitas, José Márcio Alves; Santos, Flávio Márcio Lago; Correa, Guilherme de Almeida Sellos; Maia, Lucas Russo

    2015-01-01

    Objective To demonstrate the clinical and functional results from treatment of humeral diaphysis fractures using Ender nails. Methods Eighteen patients who underwent osteosynthesis of humeral diaphysis fractures using Ender nails were evaluated. In addition to the clinical and radiographic evaluations, patients with a minimum of one year of follow-up were assessed by means of the Constant, American Shoulder and Elbow Surgeons (ASES), Mayo Clinic and Simple Shoulder Value (SSV) functional scores, and in relation to the degree of satisfaction with the final result. The fixation technique used was by means of an anterograde percutaneous route. Results All the patients achieved fracture consolidation, after a mean of 2.9 months (ranging from 2 to 4 months). The mean Constant score was 85.7 (ranging from 54 to 100) and the mean ASES score was 95.9 (ranging from 76 to 100). All the patients achieved the maximum score on the Mayo Clinic scale. Conclusion Fixation of humeral diaphysis fractures using Ender nails by means of a percutaneous technique was shown to be a method with promising preliminary results. PMID:26417566

  8. Use of a Percutaneous Pointed Reduction Clamp Before Screw Fixation to Prevent Gapping of a Fifth Metatarsal Base Fracture: A Technique Tip.

    PubMed

    Tan, Eric W; Cata, Ezequiel; Schon, Lew C

    2016-01-01

    Intramedullary screw fixation has become widely accepted as the standard of care for operative treatment of Jones fractures, allowing not only accelerated rehabilitation but also reduction of the risk of repeat fracture. The unique anatomy of the fifth metatarsal--mainly its inherent lateral curvature--makes fixation technically challenging. In general, surgical fixation should be performed with the largest screw possible, in both diameter and length, which will provide the strongest possible construct. However, an increased screw length and width have been associated with complications, including lateral gapping and distraction of the fracture site and malreduction of the fracture. The use of a pointed reduction clamp is a simple, yet effective, method of preventing iatrogenic displacement and gapping at the fracture site during placement of an intramedullary screw. Percutaneous reduction and stabilization of the fracture using this technique could help limit the complications associated with large screw fixation of Jones fractures. PMID:26188626

  9. Geomechanical Facies Concept In Fractured Resevoirs and the Application of Hybrid Numerical and Analytical Techniques for the Description of Coupled Transport In Fractured Systems

    NASA Astrophysics Data System (ADS)

    McDermott, C. I.; Wenqing, W.; Kolditz, O.

    2009-04-01

    Exploiting and geo-engineering of fractured rocks in the context of reservoir storage and utilisation is important to applications such as hydrogeology, petroleum geology, geothermal energy, nuclear waste storage and CO2-sequestration. Understanding fluid, mass and energy transport in the three dimensional fracture network is critical to the evaluation planned operating efficiency. Hydraulic, thermal, mechanical and chemical coupled processes under the typical reservoir conditions operate at different scales. Depending on whether the process is continuum dominated (e.g. transfer of stress in the rock body) or discontinuity dominated (e.g. hydraulic transport processes) different methods of numerically investigating and quantifying the system can be applied. A geomechanical facies approach provides the basis for large scale numerical analysis of the coupled processes and prediction of system response. It also provides the basis for a three dimensional holistic understanding of the reservoir systems and the appropriate investigation techniques which could be used to evaluate the capacities of the reservoirs to be investigated as well as appropriate development techniques. Concentrating on the numerical modelling there is often a difficult balance between the numerical stability criteria of the different equation systems which need to be solved to describe the interaction of the dominant processes. The introduction of analytical solutions where possible, functional dependencies and multiple meshes provides on the framework of the geo-mechanical facies concept provides an efficient and stable method for the prediction of the effect of the in situ coupling.

  10. Biomechanical comparison of two intraoperative mobilization techniques for maxillary distraction osteogenesis: Down-fracture versus non-down-fracture

    PubMed Central

    Yang, Lili; Suzuki, Eduardo Yugo; Suzuki, Boonsiva

    2014-01-01

    Purposes: The purpose of this study was to compare the distraction forces and the biomechanical effects between two different intraoperative surgical procedures (down-fracture [DF] and non-DF [NDF]) for maxillary distraction osteogenesis. Materials and Methods: Eight patients were assigned into two groups according to the surgical procedure: DF, n = 6 versus NDF, n = 2. Lateral cephalograms taken preoperatively (T1), immediately after removal of the distraction device (T2), and after at least a 6 months follow-up period (T3) were analyzed. Assessment of distraction forces was performed during the distraction period. The Mann–Whitney U-test was used to compare the difference in the amount of advancement, the maximum distraction force and the amount of relapse. Results: Although a significantly greater amount of maxillary movement was observed in the DF group (median 9.5 mm; minimum-maximum 7.9-14.1 mm) than in the NDF group (median 5.9 mm; minimum-maximum 4.4-7.6 mm), significantly lower maximum distraction forces were observed in the DF (median 16.4 N; minimum-maximum 15.1-24.6 N) than in the NDF (median 32.9 N; minimum-maximum 27.6-38.2 N) group. A significantly greater amount of dental anchorage loss was observed in the NDF group. Moreover, the amount of relapse observed in the NDF group was approximately 3.5 times greater than in the DF group. Conclusions: In this study, it seemed that, the use of the NDF procedure resulted in lower levels of maxillary mobility at the time of the maxillary distraction, consequently requiring greater amounts of force to advance the maxillary bone. Moreover, it also resulted in a reduced amount of maxillary movement, a greater amount of dental anchorage loss and poor treatment stability. PMID:25593865

  11. Sports fractures.

    PubMed Central

    DeCoster, T. A.; Stevens, M. A.; Albright, J. P.

    1994-01-01

    Fractures occur in athletes and dramatically influence performance during competitive and recreational activities. Fractures occur in athletes as the result of repetitive stress, acute sports-related trauma and trauma outside of athletics. The literature provides general guidelines for treatment as well as a variety of statistics on the epidemiology of fractures by sport and level of participation. Athletes are healthy and motivated patients, and have high expectations regarding their level of function. These qualities make them good surgical candidates. Although closed treatment methods are appropriate for most sports fractures, an aggressive approach to more complicated fractures employing current techniques may optimize their subsequent performance. PMID:7719781

  12. Two peg spade plate for distal radius fractures: A novel technique

    PubMed Central

    Hardikar, Sharad M; Prakash, Sreenivas; Hardikar, Madan S; Kumar, Rohit

    2015-01-01

    Background: The management of distal radius fractures raises considerable debate among orthopedic surgeons. The amount of axial shortening of the radius correlates with the functional disability after the fracture. Furthermore, articular incongruity has been correlated with the development of arthritis at the radiocarpal joint. We used two peg volar spade plate to provide a fixed angle subchondral support in comminuted distal radius fractures with early mobilization of the joint. Materials and Methods: Forty patients (26 males and 14 females) from a period between January 2009 and December 2011 were treated with two peg volar spade plate fixation for distal radius fracture after obtaining reduction using a mini external fixator. Patients were evaluated using the demerit point system of Gartland and Werley and Sarmiento modification of Lindstrom criteria at final followup of 24 months. Results: The average age was 43.55 years (range 23-57 years). Excellent to good results were seen in 85% (n = 34) and in all patients when rated according to the demerit point system of Gartland and Werley and Sarmiento modification of Lindstrom criteria, respectively. Complications observed were wrist stiffness in 5% (n = 2) and reflex sympathetic dystrophy in 2.5% (n = 1). Conclusions: The two peg volar spade plate provides a stable subchondral support in comminuted intraarticular fractures and maintains reduction in osteoporotic fractures of the distal radius. Early mobilization with this implant helps in restoring wrist motion and to prevent development of wrist stiffness. PMID:26538760

  13. A modified technique to extract fractured femoral stem in revision total hip arthroplasty: A report of two cases

    PubMed Central

    Akrawi, Hawar; Magra, Merzesh; Shetty, Ajit; Ng, Aaron

    2014-01-01

    INTRODUCTION The removal of well-fixed broken femoral component and cement mantle can be extremely demanding, time consuming and potentially damaging to the host bone. Different methods have been described to extract broken femoral stem yet this remains one of the most challenging prospect to the revision hip surgeon. PRESENTATION OF CASE The authors present two cases underwent a modified sliding cortical window technique utilising a tungsten carbide drill, Charnley pin retractor and an orthopaedic mallet to aid extraction of a fractured cemented femoral stem in revision total hip arthroplasty. DISCUSSION The modified technique offers a simple and controlled method in extracting a well fixed fractured cemented femoral stem. It has the advantage of retaining the cement mantle with subsequent good seal of the femoral cortical window secured with cable ready system. Furthermore, tungsten carbide drill bit and Charnley pin retractor are relatively readily available to aid the extraction of the broken stem. Finally, it yields the option of implanting a standard femoral stem and obviates the need for bypassing the cortical window with long revision femoral component. CONCLUSION Fractured femoral stem is a rare yet a complex and very demanding prospect to both patients and hip surgeons. The sliding cortical window technique utilising tungsten carbide drill and Charnley pin retractor is technically easy and most importantly; preserves host bone stock with cement-in-cement revision hip arthroplasty. We believe this technique can be added to the armamentarium of revision hip surgeon when faced with the challenge of extracting a fractured cemented femoral stem. PMID:24858980

  14. Reasonable Temperature Schedules for Cold or Hot Charging of Continuously Cast Steel Slabs

    NASA Astrophysics Data System (ADS)

    Li, Yang; Chen, Xin; Liu, Ke; Wang, Jing; Wen, Jin; Zhang, Jiaquan

    2013-12-01

    Some continuously cast steel slabs are sensitive to transverse fracture problems during transportation or handling away from their storage state, while some steel slabs are sensitive to surface transverse cracks during the following rolling process in a certain hot charging temperature range. It is revealed that the investigated steel slabs with high fracture tendency under room cooling condition always contain pearlite transformation delayed elements, which lead to the internal brittle bainitic structure formation, while some microalloyed steels exhibit high surface crack susceptibility to hot charging temperatures due to carbonitride precipitation. According to the calculated internal cooling rates and CCT diagrams, the slabs with high fracture tendency during cold charging should be slowly cooled after cutting to length from hot strand or charged to the reheating furnace directly above their bainite formation temperatures. Based on a thermodynamic calculation for carbonitride precipitation in austenite, the sensitive hot charging temperature range of related steels was revealed for the determination of reasonable temperature schedules.

  15. Effect of post type and restorative techniques on the strain and fracture resistance of flared incisor roots.

    PubMed

    Silva, Gisele Rodrigues da; Santos-Filho, Paulo César de Freitas; Simamoto-Júnior, Paulo Cézar; Martins, Luis Roberto Marcondes; Mota, Adérito Soares da; Soares, Carlos José

    2011-01-01

    Restoring flared endodontically treated teeth continues to be a challenge for clinicians. This study evaluated the effect of post types and restorative techniques on the strain, fracture resistance, and fracture mode of incisors with weakened roots. One hundred five endodontically treated bovine incisors roots (15 mm) were divided into 7 groups (n=15). The two control groups were (C) intact roots restored with Cpc (cast posts and core) or Gfp (glass fiber posts). The five experimental groups were (F) flared roots restored with GfpAp (Gfp associated with accessory glass fiber posts), GfpRc (anatomic Gfp, relined with composite resin), and GfpRcAp (anatomized Gfp with resin and accessory glass fiber posts). All teeth were restored with metal crowns. Mechanical fatigue was performed with 3x10(5)/50 N. Specimens were loaded at 45º, and the strain values (μS) were obtained on root buccal and proximal surfaces. Following that, the fracture resistance (N) was measured. One-way ANOVA and Tukey's HSD tests (α=0.05) were applied, and failure mode was checked. No significant difference in strain values among the groups was found. Cpc presented lower fracture resistance and more catastrophic failures in flared roots. Gfp associated with composite resin or accessory glass fiber posts seems to be an effective method to improve the biomechanical behavior of flared roots. PMID:21915521

  16. EVALUATION OF PATIENTS UNDERGOING FIXATION OF DIAPHYSEAL HUMERAL FRACTURES USING THE MINIMALLY INVASIVE BRIDGE-PLATE TECHNIQUE

    PubMed Central

    Superti, Mauro José; Martynetz, Fábio; Falavinha, Ricardo Sprenger; Fávaro, Rodrigo Caldonazzo; Boas, Luis Felipe Villas; Filho, Salim Mussi; Martynetz, Juliano; Ribas, Bruno

    2015-01-01

    Objective: The aim was to describe the experience of our group in treating humeral shaft fractures using the bridge–plate technique via an anterior approach. Methods: Seventeen patients with acute diaphyseal humeral fractures with an indication for surgical treatment who were operated in 2006–2010 were evaluated. The AO and Gustilo & Anderson classifications were used. All the patients were operated using the anterior bridge-plate technique and completed a follow–up period of at least twelve months. Results: Sixteen men and one woman were treated. Their mean age was 31.8 years (18–52). Among the injury mechanisms found were: five motorcycle accidents, four car accidents, three fractures due to firearm projectiles, two falls to the ground and finally, with one case each, assault, crushing and being run over. Eight patients had open fractures: two grade I, one grade II, four grade IIIa and one grade IIIb, according to the Gustilo-Anderson classification. In relation to the AO classification, we found: one 12A1, three 12A2, four 12A3, one 12B1, four 12 B2, three 12B3 and one 12C2. The mean postoperative follow-up was 25 months (12–48). As complications, two patients had pain in the elbow and a ROM deficit and one had deep infection. The mean time taken to achieve consolidation was 17.5 weeks. There was no loss of reduction, pseudarthrosis or malunion in this series of patients. Conclusion: The authors believe that the technique described has low rates of complications and morbidity, with good initial results, although the series is limited by the small sample. PMID:27042639

  17. Use of Ilizarov Fixator for Grade III B Open Olecranon Fracture: a Case Report and Surgical Technique

    PubMed Central

    Sharad Nemade, Pradip; Dash, Kumar Kaushik; Patwardhan, Tanvi Yeshwant; Londhe, Pravin Vasant

    2015-01-01

    Introduction: External fixator application can be difficult for olecranon fractures in presence of large degloving injuries. We describe use of simple Ilizarov ring fixator construct for grade IIIB open olecranon fracture management. Case Report: A 45-year-old female with Grade III B open comminuted olecranon fracture (30*15cm degloving area) and ulnar nerve palsy was treated with a novel ring fixator construct. Two cut-end olive wires were passed from the proximal olecranon across the fracture site in intramedullary fashion exiting dorsally at mid-ulnar level through healthy skin and were attached to an Ilizarov half ring secured by perpendicular wires. The olive wires were tensioned, achieving compression and stability. Range of motion (ROM) exercises could be started quickly as the elbow was not spanned. Wound healed after skin grafting and at one-year follow-up the patient has good functional results (PRE 7, DASH 9.48), elbow ROM 10°-130°, 75° pronation and 85° supination. The patient returned to pre-injury occupational activities and had no pain. At three-year follow-up, the x-ray and CT showed union of olecranon fragment with well-maintained congruency. Conclusion: Internal fixation in most cases may be precluded by the soft tissue trauma and risk of infection. In addition, the small proximal fragment precludes a stable external fixation. In this technique, the hardware is kept away from the open wound allowing better wound inspection and care. The intramedullary olive wires provide compression and stability, and thus allow early ROM. Ilizarov half-ring and olive wire fixation can be an useful option for management of high grade open olecranon fractures because of its advantages, viz. stable fixation, minimal internal hardware, optimal wound care, immediate initiation of range of motion, and good outcome. PMID:27299012

  18. Particle Imaging Velocimetry Technique Development for Laboratory Measurement of Fracture Flow Inside a Pressure Vessel Using Neutron Imaging

    SciTech Connect

    Polsky, Yarom; Bingham, Philip R; Bilheux, Hassina Z; Carmichael, Justin R

    2015-01-01

    This paper will describe recent progress made in developing neutron imaging based particle imaging velocimetry techniques for visualizing and quantifying flow structure through a high pressure flow cell with high temperature capability (up to 350 degrees C). This experimental capability has great potential for improving the understanding of flow through fractured systems in applications such as enhanced geothermal systems (EGS). For example, flow structure measurement can be used to develop and validate single phase flow models used for simulation, experimentally identify critical transition regions and their dependence on fracture features such as surface roughness, and study multiphase fluid behavior within fractured systems. The developed method involves the controlled injection of a high contrast fluid into a water flow stream to produce droplets that can be tracked using neutron radiography. A description of the experimental setup will be provided along with an overview of the algorithms used to automatically track droplets and relate them to the velocity gradient in the flow stream. Experimental results will be reported along with volume of fluids based simulation techniques used to model observed flow.

  19. FIXATION OF FRACTURES OF THE DISTAL EXTREMITY OF THE RADIUS USING THE MODIFIED KAPANDJI TECHNIQUE: EVALUATION OF THE RADIOLOGICAL RESULTS

    PubMed Central

    Neto, Antonio Piva; Lhamby, Fabio Colla

    2015-01-01

    To demonstrate a simple and efficacious option for treating fractures of the distal extremity of the radius using Kirschner wires. Methods: Between September 2008 and April 2009, 48 patients with fractures of the distal extremity of the radius, classified as A3 according to the AO classification, were treated surgically using a modification of the Kapandji technique. Results: Out of the 48 wrists operated, 42 (87.5%) presented postoperative measurements within the acceptable limits. We used the parameters of McQuenn and Caspers who considered that the radial angulation should be wider than 19° and the volar angulation should be narrower than -12°. All the postoperative volar inclination measurements were narrower than -3°. The mean preoperative radial inclination was 13.14° and the mean postoperative value was 21.18°. The mean preoperative volar inclination was 28.75° and the mean postoperative value was 3.31°. The mean preoperative radial height was 5.25 mm and the mean postoperative value was 9.48 mm. Conclusion: The technique described here had excellent stability for treating fractures of the distal extremity of the radius classified as A3. It was easy to implement and minimally invasive, with minimal surgical complications, and it was inexpensive. PMID:27027023

  20. Development of Reservoir Characterization Techniques and Production Models for Exploiting Naturally Fractured Reservoirs

    SciTech Connect

    Wiggins, Michael L.; Brown, Raymon L.; Civan, Faruk; Hughes, Richard G.

    2003-02-11

    This research was directed toward developing a systematic reservoir characterization methodology which can be used by the petroleum industry to implement infill drilling programs and/or enhanced oil recovery projects in naturally fractured reservoir systems in an environmentally safe and cost effective manner. It was anticipated that the results of this research program will provide geoscientists and engineers with a systematic procedure for properly characterizing a fractured reservoir system and a reservoir/horizontal wellbore simulator model which can be used to select well locations and an effective EOR process to optimize the recovery of the oil and gas reserves from such complex reservoir systems.

  1. Influence of immediate dentin sealing techniques on cuspal deflection and fracture resistance of teeth restored with composite resin inlays.

    PubMed

    Oliveira, L; Mota, E G; Borges, G A; Burnett, L H; Spohr, A M

    2014-01-01

    SUMMARY This research evaluated the influence of immediate dentin sealing (IDS) techniques on cuspal deflection and fracture resistance of teeth restored with composite resin inlays. Forty-eight maxillary premolars were divided into four groups: G1, sound teeth (control); G2, without IDS; G3, IDS with Clearfil SE Bond (CSE); and G4, IDS with CSE and Protect Liner F. The teeth from groups 2, 3, and 4 received mesio-distal-occlusal preparations. The impressions were made with vinyl polysiloxane, followed by provisional restoration and storage in water for seven days. The impressions were poured using type IV die stone, and inlays with Filtek Z250 composite resin were built over each cast. The inlays were luted with Panavia F. After storage in water for 72 hours, a 200-N load was applied on the occlusal surface using a metal sphere connected to a universal testing machine, and the cuspal deflection was measured with a micrometer. The specimens were then submitted to an axial load until failure. The following mean cuspal deflection (μm) and mean fracture resistance (N) followed by the same lowercase letter represent no statistical difference by analysis of variance and Tukey (p<0.05): cuspal deflection: G1, 3.1 ± 1.5(a); G2, 10.3 ± 4.6(b); G3, 5.5 ± 1.8(ac); and G4, 7.7 ± 5.1(bc); fracture resistance: G1, 1974 ± 708(a); G2, 1162 ± 474(b); G3, 700 ± 280(b); and G4, 810 ± 343(b). IDS with CSE allowed cuspal deflection comparable with that associated with sound teeth. The application of Protect Liner F did not contribute to a decrease in cuspal deflection. The IDS techniques did not influence the fracture resistance of teeth. PMID:23718211

  2. SUB-SLAB PROBE INSTALLATION

    EPA Science Inventory

    Sub-slab sampling has become an integral part of vapor intrusion investigations. It is now recommended in guidance documents developed by EPA and most states. A method for sub-slab probe installation was devised in 2002, presented at conferences through 2005, and finally docume...

  3. Treatment of Unstable Thoracolumbar Fractures through Short Segment Pedicle Screw Fixation Techniques Using Pedicle Fixation at the Level of the Fracture: A Finite Element Analysis

    PubMed Central

    Li, Changqing; Zhou, Yue; Wang, Hongwei; Liu, Jun; Xiang, Liangbi

    2014-01-01

    Objective To compare the von Mises stresses of the internal fixation devices among different short segment pedicle screw fixation techniques to treat thoracic 12 vertebral fractures, especially the mono-segment pedicle screw fixation and intermediate unilateral pedicle screw fixation techniques. Methods Finite element methods were utilised to investigate the biomechanical comparison of the four posterior short segment pedicle screw fixation techniques (S4+2: traditional short-segment 4 pedicle screw fixation [SPSF]; M4+2: mono-segment pedicle screw fixation; I6+2: intermediate bilateral pedicle screw fixation; and I5+2: intermediate unilateral pedicle screw fixation). Results The range of motion (ROM) in flexion, axial rotation, and lateral bending was the smallest in the I6+2 fixation model, followed by the I5+2 and S4+2 fixation models, but lateral bending was the largest in the M4+2 fixation model. The maximal stress of the upper pedicle screw is larger than the lower pedicle screw in S4+2 and M4+2. The largest maximal von Mises stress was observed in the upper pedicle screw in the S4+2 and M4+2 fixation models and in the lower pedicle screw in the I6+2 and I5+2 fixation models. The values of the largest maximal von Mises stress of the pedicle screws and rods during all states of motion were 263.1 MPa and 304.5 MPa in the S4+2 fixation model, 291.6 MPa and 340.5 MPa in the M4+2 fixation model, 182.9 MPa and 263.2 MPa in the I6+2 fixation model, and 269.3 MPa and 383.7 MPa in the I5+2 fixation model, respectively. Comparing the stress between different spinal loadings, the maximal von Mises stress of the implants were observed in flexion in all implanted models. Conclusion Additional bilateral pedicle screws at the level of the fracture to SPSF may result in a stiffer construct and less von Mises stress for pedicle screws and rods. The largest maximal von Mises stress of the pedicle screws during all states of motion were observed in the mono-segment pedicle

  4. [Thermoluminescence Slab Dosimeter].

    PubMed

    Shinsho, Kiyomitsu; Koba, Yusuke; Tamatsu, Satoshi; Sakurai, Noboru; Wakabayashi, Genichiro; Fukuda, Kazusige

    2013-01-01

    In 1953 F. Daniels et al. used the property of thermoluminescence in dosimetry for the first time. Since then, numerous TLD have been developed. 2D TLD was investigated for the first time in 1972 by P Broadhead. However, due to excessive fading, difficulties with handling and the time required for measurements, development stalled. At the current time, the majority of TLD are used in small scale, localized dosimetry with a wide dynamic range and personal dosimeters for exposure management. Urushiyama et. al. have taken advantage of the commoditization of CCD cameras in recent years--making large area, high resolution imaging easier--to introduce and develop a 2D TLD. It is expected that these developments will give rise to a new generation of applications for 2D TL dosimetry. This paper introduces the "TL Slab Dosimeter" developed jointly by Urushiyama et. al. and our team, its measurement system and several typical usage scenarios. PMID:24893451

  5. Treatment of tibial eminence fractures with arthroscopic suture fixation technique: a retrospective study

    PubMed Central

    Yuan, Yanhao; Huang, Xiaohan; Zhang, Yanjie; Wang, Zhanchao

    2015-01-01

    Aims: The present study aims to investigate the clinical outcomes of arthroscopic suture fixation in treating tibial eminence fracture with a retrospective study design of two years’ follow-up. Methods: A total of 33 patients with imaging evidence of tibial eminence avulsion fractures who underwent arthroscopic surgery between 2008 and 2012 were included in this study. The inclusion criteria for the study were a displaced tibial eminence avulsion fracture and anterior knee instability of grade II or higher inskeletally mature patients. These patients were treated with arthroscopic suture fixation and followed with a mean period of 24 months. Anteroposterior and lateral radiographs were obtained 3 months postoperatively to assess fracture healing. At 24 months after surgery, all patients were evaluated by an independent orthopaedic professor with clinical examination like anteroposterior laxity (Lachman-Noulis and anterior drawer tests) and Rolimeter knee tester (Aircast, Vista, CA). Knee range of motion was evaluated actively and passively with a goniometer. Knee function was evaluated by the Lysholm and International Knee Documentation Committee (IKDC) scores. Knee radiographs in standing anteroposterior, standing lateral, and Merchant views were examined for alignment, joint space narrowing, and degenerative knee changes. Results: No major complication like infection, deep venous thrombosis, or neurovascular deficit happened peri-operatively. At the final follow-up, there were no symptoms of instability and no clinical signs of ACL deficiency. Radiographs showed that all fractures healed 3 months post-operative, but at the last follow-up, there was one person with degenerative changes like joint space narrowing in radiographs. Anterior translation of the tibia was 0.47 mm on average (0 to 2.5 mm) compared with the uninjured side. Range-of-motion measurement showed a mean extension deficit of 1.5° (0° to 5°) and a mean flexion deficit of 2.7° (0° to 10

  6. Burnei’s “double X" internal fixation technique for supracondylar humerus fractures in children: indications, technique, advantages and alternative interventions

    PubMed Central

    Georgescu, I; Gavriliu, S; Pârvan, A; Martiniuc, A; Japie, E; Ghiță, R; Drăghici, I; Hamei, S; Ţiripa, I; El Nayef, T; Dan, D

    2013-01-01

    Background. The Study and Research Group in Pediatric Orthopedics-2012 initated this retrospective study due to the fact that in Romania and in other countries, the numerous procedures do not ensure the physicians a definite point of view related to the therapeutic criteria in the treatment of supracondylar fractures. That is why the number of complications and their severity brought into notice these existent deficiencies. In order to correct some of these complications, cubitus varus or valgus, Prof. Al. Pesamosca communicated a paper called "Personal procedure in the treatment of posttraumatic cubitus varus" at the County Conference from Bacău, in June 24, 1978. This procedure has next been made popular by Prof. Gh. Burnei and his coworkers by operating patients with cubitus varus or valgus due to supracondylar humeral fractures and by presenting papers related to the subject at the national and international congresses. The latest paper regarding this problem has been presented at the 29th Annual Meeting of the European Pediatric Orthopedic Society in Zagreb, Croatia, April 7-10, 2010, being titled “Distal humeral Z-osteotomy for posttraumatic cubitus varus or valgus", having as authors Gh. Burnei, Ileana Georgescu, Ştefan Gavriliu, Costel Vlad and Daniela Dan. As members of this group, based on the performed studies, we wish to make popular this type of osteosynthesis, which ensures a tight fixation, avoids complications and allows a rapid postoperative activity. Introduction. The acknowledged treatment for these types of fractures is the orthopedic one and it must be accomplished as soon as possible, in the first 6 hours, by reduction and cast immobilization or by closed or open reduction and fixation, using one of the several methods (Judet, Boehler, Kapandji, San Antonio, San Diego, Burnei’s double X technique). The exposed treatment is indicated in irreducible supracondylar humeral fractures, in reducible, but unstable type, in polytraumatized

  7. [Arthroscopically assisted osteosynthesis of dorsally tilted intraarticular distal radius fractures--technique and results].

    PubMed

    Lutz, M; Wieland, T; Deml, C; Erhart, S; Rudisch, A; Klestil, T

    2014-10-01

    The present paper describes the indication and application of an arthroscopically assisted osteosynthesis for distal radius fractures. Visualisation of articular incongruency is emphasised with special regard to articular fracture fragment reduction. In addition to that, classification of soft tissue injuries and treatment options are discussed. The final clinical and radiological results of 17 patients are presented: DASH and PRWE averaged 4.9 and 6.0 respectively. Active range of motion measured 123° for flexion/extension, 51° for radial and ulnar deviation and 163° for pronosupination, which is 87%, 98% and 97%, respectively, compared with the opposite wrist. Radial inclination at final follow-up was 23°, palmar tilt measured 6° and ulnar variance averaged -1.2 mm. The scapholunate gap at follow-up was 1.6 mm, and the scapholunate angle measured 57°. PMID:25290269

  8. Fracture toughness of solid oxide fuel cell anode substrates determined by a double-torsion technique

    NASA Astrophysics Data System (ADS)

    Pećanac, G.; Wei, J.; Malzbender, J.

    2016-09-01

    Planar solid oxide fuel cell anode substrates are exposed to high mechanical loads during assembly, start-up, steady-state operation and thermal cycling. Hence, characterization of mechanical stability of anode substrates under different oxidation states and at relevant temperatures is essential to warrant a reliable operation of solid oxide fuel cells. As a basis for mechanical assessment of brittle supports, two most common anode substrate material variants, NiO-3YSZ and NiO-8YSZ, were analyzed in this study with respect to their fracture toughness at room temperature and at a typical stack operation temperature of 800 °C. The study considered both, oxidized and reduced materials' states, where also an outlook is given on the behavior of the re-oxidized state that might be induced by malfunctions of sealants or other functional components. Aiming at the improvement of material's production, different types of warm pressed and tape cast NiO-8YSZ substrates were characterized in oxidized and reduced states. Overall, the results confirmed superior fracture toughness of 3YSZ compared to 8YSZ based composites in the oxidized state, whereas in the reduced state 3YSZ based composites showed similar fracture toughness at room temperature, but a higher value at 800 °C compared to 8YSZ based composites. Complementary microstructural analysis aided the interpretation of mechanical characterization.

  9. Fracture resistance of premolars with one remaining cavity wall restored using different techniques.

    PubMed

    Kivanç, Bagdagül Helvacioglu; Alaçam, Tayfun; Görgül, Güliz

    2010-05-01

    The aim of the study was to compare the fracture resistance of maxillary premolars with one remaining cavity wall restored using different post systems. Forty-eight maxillary premolars were endodontically treated and randomly assigned to four groups for postcore restoration. The first three test groups were restored with polyethylene woven fiber posts, custom-made glass fiber-reinforced composite posts, and titanium posts respectively. In the control Group 4, standardized cavities (3.5 x 1.5 mm) were prepared in the palatal canal entrance and filled with a resin composite. All the specimens were then restored with a resin composite crown seated on the post. Load was applied with a stainless steel ball (1 mm/min), and the failure modes of all specimens were evaluated. There were no significant differences in fracture resistance and failure mode among the different restorative materials (p>0.05). Within the limitations of this in vitro study, it was concluded that the presence and type of post did not influence the fracture load and failure mode of maxillary premolar teeth with one remaining cavity wall. PMID:20448409

  10. Refinement of digital image correlation technique to investigate the fracture behaviour of refractory materials

    NASA Astrophysics Data System (ADS)

    Belrhiti, Y.; Pop, O.; Germaneau, A.; Doumalin, P.; Dupré, J. C.; Huger, M.; Chotard, T.

    2016-03-01

    Refractory materials exhibit a heterogeneous microstructure consisting in coarse aggregates surrounded by fine grains that form an aggregate/matrix composite. This heterogeneous microstructure often leads to a complex mechanical behaviour during loading. This paper is devoted to the study, thanks to an optical method, Digital Image Correlation (DIC), of the fracture behaviour of two industrial refractory materials in relation with their microstructure resulting from both the chosen constituents and the sintering process. The aim is here, specifically, to highlight and to characterize the evolution of kinematic fields (displacement and strain) observed at the surface of sample during a wedge splitting test typically used to quantify the work of fracture. DIC is indeed a helpful and effective tool, in the topic of experimental mechanics, for the measurement of deformation in a planar sample surface. This non-contact optical method directly provides full-field displacements by comparing the digital images of the sample surface obtained before and during loading. In the present study, DIC has been improved to take into account the occurrence of cracks and performed so as to better identify the early stage of the cracking behaviour. The material transformation, usually assumed homogeneous inside each DIC subset, is thus more complex and a discontinuity of displacement should be taken into account. Then each subset which crosses a crack can be cut in two parts with different kinematics. By this way, it is possible to automatically find the fracture paths and follow the crack geometries (length, opening).

  11. Surgical Technique of Corrective Osteotomy for Malunited Distal Radius Fracture Using the Computer-Simulated Patient Matched Instrument.

    PubMed

    Murase, Tsuyoshi

    2016-06-01

    The conventional corrective osteotomy for malunited distal radius fracture that employs dorsal approach and insertion of a trapezoidal bone graft does not always lead to precise correction or result in a satisfactory surgical outcome. Corrective osteotomy using a volar locking plate has recently become an alternative technique. In addition, the use of patient-matched instrument (PMI) via computed tomography simulation has been developed and is expected to simplify surgical procedures and improve surgical precision. The use of PMI makes it possible to accurately position screw holes prior to the osteotomy and simultaneously perform the correction and place the volar locking plate once the osteotomy is completed. The bone graft does not necessarily require a precise block form, and the problem of the extensor tendon contacting the dorsal plate is avoided. Although PMI placement and soft tissue release technique require some degree of specialized skill, they comprise a very useful surgical procedure. On the other hand, because patients with osteoporosis are at risk of peri-implant fracture, tandem ulnar shortening surgery should be considered to avoid excessive lengthening of the radius. PMID:27454626

  12. New Packaging for Amplifier Slabs

    SciTech Connect

    Riley, M.; Thorsness, C.; Suratwala, T.; Steele, R.; Rogowski, G.

    2015-03-18

    The following memo provides a discussion and detailed procedure for a new finished amplifier slab shipping and storage container. The new package is designed to maintain an environment of <5% RH to minimize weathering.

  13. A Simple Technique for the Positioning of a Patient with an above Knee Amputation for an Ipsilateral Extracapsular Hip Fracture Fixation

    PubMed Central

    Davarinos, N.; Ellanti, P.; McCoy, G.

    2013-01-01

    The positioning of the patient on the fracture table is critical to the successful reduction and operative fixation of hip fractures which are fixed using the dynamic hip screw system (DHS). There is a standard setup which is commonly used with relative ease. Yet the positioning of patients with amputations either above or below knee of the affected side can pose a significant challenge. We describe a novel positioning technique used on a 51-year old patient with a right above knee amputation who sustained an intertrochanteric extracapsular hip fracture. PMID:24416607

  14. Active part of Charlie--Gibbs fracture zone: A study using sonar and other geophysical techniques

    SciTech Connect

    Searle, R.

    1981-01-10

    A short survey with Gloria side-scan sonar and other geophysical instruments has revealed new information about Charlie--Gibbs fracture zone between 29/sup 0/ and 36 /sup 0/W. The traces of two transform faults have been clearly delineated. They fit small circles about the pole of rotation with an rms error of only about 1 km, but they do not always follow the deepest parts of the transform valleys. The transforms are joined by a short spreading center at 31 /sup 0/45 'W. The median transverse ridge appears to have been produced by normal seafloor spreading at this center and bears identifiable Vine-Matthews magnetic anomalies. A transverse ridge along the eastern inactive part of the northern transform may be an intrusive feature. Considerable thickness of sediment appear to have been deposited in the northern transform valley from Norwegian Sea overflow water passing through the fracture zone, but transverse ridges have prevented the sediment reaching the southern valley.

  15. Approximate techniques for predicting size effects on cleavage fracture toughness (J{sub c})

    SciTech Connect

    Kirk, M.T.; Dodds, R.H. Jr.

    1993-07-01

    This investigation examines the ability of an elastic T-stress analysis coupled with modified boundary layer (MBL) solution to predict stresses ahead of a crack tip in a variety of planar geometries. The approximate stresses are used as input to estimate the effective driving force for cleavage fracture (J{sub 0}) using the micromechanically based approach introduced by Dodds and Anderson. Finite element analyses for a wide variety of planar cracked geometries are conducted which have elastic biaxiality parameters ({beta}) ranging from {minus}0.99 (very low constraint) to +2.96 (very high constraint). The magnitude and sign of {beta} indicate the rate at which crack-tip constraint changes with increasing applied load. All results pertain to a moderately strain hardening material (strain hardening exponent ({eta}) of 10). These analyses suggest that {beta} is an effective indicator of both the accuracy of T-MBL estimates of J{sub 0} and of applicability limits on evolving fracture analysis methodologies (i.e. T-MBL, J-Q, and J/J{sub 0}). Specifically, when 1{beta}1>0.4 these analyses show that the T-MBL approximation of J{sub 0} is accurate to within 20% of a detailed finite-element analysis. As ``structural type`` configurations, i.e. shallow cracks in tension, generally have 1{beta}1>0.4, it appears that only an elastic analysis may be needed to determine reasonably accurate J{sub 0} values for structural conditions.

  16. Topical report on subsurface fracture mapping from geothermal wellbores. Phase I. Pulsed radar techniques. Phase II. Conventional logging methods. Phase III. Magnetic borehole ranging

    SciTech Connect

    Hartenbaum, B.A.; Rawson, G.

    1980-09-01

    To advance the state-of-the-art in Hot Dry Rock technology, an evaluation is made of (i) the use of radar to map far-field fractures, (ii) the use of more than twenty different conventional well logging tools to map borehole-fracture intercepts, and (iii) the use of magnetic dipole ranging to determine the relative positions of the injection well and the production well within the fractured zone. It is found that according to calculations, VHF backscatter radar has the potential for mapping fractures within a distance of 50 +- 20 meters from the wellbore. A new technique for improving fracture identification is presented. Analyses of extant data indicate that when used synergistically the (1) caliper, (2) resistivity dipmeter, (3) televiewer, (4) television, (5) impression packer, and (6) acoustic transmission are useful for mapping borehole-fracture intercepts. Improvements in both data interpretation techniques and high temperature operation are required. The surveying of one borehole from another appears feasible at ranges of up to 200 to 500 meters by using a low frequency magnetic field generated by a moderately strong dipole source (a solenoid) located in one borehole, a sensitive B field detector that traverses part of the second borehole, narrow band filtering, and special data inversion techniques.

  17. Trans-Endplate Pedicle Pillar System in Unstable Spinal Burst Fractures: Design, Technique, and Mechanical Evaluation

    PubMed Central

    Zhao, Chunfeng; Hongo, Michio; Ilharreborde, Brice; Zhao, Kristin D.; Currier, Bradford L.; An, Kai-Nan

    2015-01-01

    Background Short-segment pedicle screw instrumentation (SSPI) is used for unstable burst fractures to correct deformity and stabilize the spine for fusion. However, pedicle screw loosening, pullout, or breakage often occurs due to the large moment applied during spine motion, leading to poor outcomes. The purpose of this study was to test the ability of a newly designed device, the Trans-Endplate Pedicle Pillar System (TEPPS), to enhance SSPI rigidity and decrease the screw bending moment with a simple posterior approach. Methods Six human cadaveric spines (T11-L3) were harvested. A burst fracture was created at L1, and the SSPI (Moss Miami System) was used for SSPI fixation. Strain gauge sensors were mounted on upper pedicle screws to measure screw load bearing. Segmental motion (T12-L2) was measured under pure moment of 7.5 Nm. The spine was tested sequentially under 4 conditions: intact; first SSPI alone (SSPI-1); SSPI+TEPPS; and second SSPI alone (SSPI-2). Results SSPI+TEPPS increased fixation rigidity by 41% in flexion/extension, 28% in lateral bending, and 37% in axial rotation compared with SSPI-1 (P<0.001), and it performed even better compared to SSPI-2 (P<0.001 for all). Importantly, the bending moment on the pedicle screws for SSPI+TEPPS was significantly decreased 63% during spine flexion and 47% in lateral bending (p<0.001). Conclusion TEPPS provided strong anterior support, enhanced SSPI fixation rigidity, and dramatically decreased the load on the pedicle screws. Its biomechanical benefits could potentially improve fusion rates and decrease SSPI instrumentation failure. PMID:26502352

  18. A new technique for lag screw placement in the dynamic hip screw fixation of intertrochanteric fractures: decreasing radiation time dramatically

    PubMed Central

    Sheng, Wei-Chao; Li, Jia-Zhen; Chen, Sheng-Hua

    2008-01-01

    The goal of this study was to confirm the decrease in radiation time required for a new technique to place dynamic hip screws (DHS) in intertrochanteric fractures. Seventy-six patients were treated with DHS by either the new technique (NT) or the conventional technique (CT). The width of femoral shaft, the length of the hip screw to be implanted into the injured side, and the distance between the tip of the greater trochanter and the entry point of the guide wire were measured at the uninjured side on the anteroposterior pelvic radiograph preoperatively, and the actual width of the injured femoral shaft was measured intra-operatively. Finally, the entry point and the length of hip screw were obtained through an equation. Mean radiation time of the NT patients (24.57 ± 7.80 s) was significantly shorter than the CT patients (54.2 ± 18.26 s) (P  < 0.001). The new technique decreased radiation time dramatically in DHS fixation. PMID:18265981

  19. Nose fracture

    MedlinePlus

    Fracture of the nose; Broken nose; Nasal fracture; Nasal bone fracture; Nasal septal fracture ... A fractured nose is the most common fracture of the face. It ... with other fractures of the face. Sometimes a blunt injury can ...

  20. Slab coupled optical fiber sensor calibration

    NASA Astrophysics Data System (ADS)

    Whitaker, B.; Noren, J.; Chadderdon, S.; Wang, W.; Forber, R.; Selfridge, R.; Schultz, S.

    2013-02-01

    This paper presents a method for calibrating slab coupled optical fiber sensors (SCOS). An automated system is presented for selecting the optimal laser wavelength for use in SCOS interrogation. The wavelength calibration technique uses a computer sound card for both the creation of the applied electric field and the signal detection. The method used to determine the ratio between the measured SCOS signal and the applied electric field is also described along with a demonstration of the calibrated SCOS involving measuring the dielectric breakdown of air.

  1. Slab fluid release: localized in space and time

    NASA Astrophysics Data System (ADS)

    John, T.; Gussone, N. C.; Podladchikov, Y. Y.

    2012-12-01

    the amount of precipitated carbonate during flow. This indicates that some fraction of the slab fluid was liberated by sub-crustal dehydration, then transported over up to km scales within the overlying oceanic crust. Lithium chronometry is currently the tool of choice to obtain information on the duration of fluid flow and fluid-rock interaction. In a structure like our reaction selvage, the advective component of the element transport is focused into fracture-related porosity, e.g., into the vein. Consequently, for such a fluid-dominated system, element transport within unfractured rock adjacent to a fluid conduit is dominantly diffusive and can be treated as having resulted from bulk diffusion. Element transport occurs exclusively within the fluid-filled interconnected porosity and exchange with minerals occurs through dissolution-precipitation reactions. While the Ca isotopes indicate that intra slab fluid flow is highly channelized and that the released fluids travel through slabs along major conduits, Li-diffusion modeling shows that this fluid flow occurs in a pulse-like manner of less than ~200 years duration. This implies that even though the overall slab dehydration is a continuous process, dehydrating slabs release their fluid by short-lived, channelized fluid-flow events. Such pulses could feed arc magma sources with aqueous fluids, with these fluids traversing the slab-wedge interface in transient hydraulic fractures.

  2. Electromagnetic and ultrasonic investigations on a roman marble slab

    NASA Astrophysics Data System (ADS)

    Capizzi, Patrizia; Cosentino, Pietro L.

    2010-05-01

    The archaeological Museum of Rome (Museo delle Terme di Diocleziano) asked our group about the physical consistency of a marble slab (II - III century AD) that has recently fallen down during the transportation for an exhibition. In fact, due to insurance conflict, it was necessary to control the new fractures due to the recent accident and distinguish them from the ancient ones. The sculptured slab (today's size is 1280 x 70 x 9 cm), cut at the ends for a re-use as an inscription in the rear face, was restored (assemblage of different broken parts and cleaning) in contemporary times. We used different methodologies to investigate the slab: namely a pacometer (Protovale Elcometer) to individuate internal coupling pins, GPR (2000 MHz) and Ultrasonic (55 kHz) tomographic high-density surveys to investigate the internal extension of all the visible fractures and to search for the unknown internal ones. For every methodology used the quality of the acquired data was relatively high. They have been processed and compared to give a set of information useful for the bureaucratic problems of the Museum. Later on, the data have been processed in depth, for studying how to improve the data processing and for extracting all the information contained in the whole set of experimental data. Finally, the results of such a study in depth are exposed in detail.

  3. Phase conjugated slab laser designator

    SciTech Connect

    Chandra, S.; Paul, J.L.

    1989-06-06

    A laser designator is described comprising a laser pump means; a high power phase conjugated slab laser amplifier formed of GSGG:Cr:Nd as a lasing material on one side of the pump means; a low power rod shaped laser oscillator on the opposite side of the pump means; and a first plurality of optical reflecting and refracting means for directing and shaping a laser beam which surrounds the pump means and passes through the rod and slab; and a telescope means coupled to the beam to direct it to a distant target.

  4. A wrinkly phononic crystal slab

    NASA Astrophysics Data System (ADS)

    Bayat, Alireza; Gordaninejad, Faramarz

    2015-03-01

    The buckling induced surface instability is employed to propose a tunable phononic crystal slab composed of a stiff thin film bonded on a soft elastomer. Wrinkles formation is used to generate one-dimensional periodic scatterers at the surface of a finitely thick slab. Wrinkles' pattern change and corresponding stress is employed to control wave propagation triggered by a compressive strain. Simulation results show that the periodic wrinkly structure can be used as a transformative phononic crystal which can switch band diagram of the structure in a reversible behavior. Results of this study provide opportunities for the smart design of tunable switch and elastic wave filters at ultrasonic and hypersonic frequency ranges.

  5. OSTEOSYNTHESIS OF PROXIMAL HUMERAL END FRACTURES WITH FIXED-ANGLE PLATE AND LOCKING SCREWS: TECHNIQUE AND RESULTS

    PubMed Central

    Cohen, Marcio; Amaral, Marcus Vinicius; Monteiro, Martim; Brandão, Bruno Lobo; Motta Filho, Geraldo Rocha

    2015-01-01

    Describe the results of proximal humeral fractures surgically treated with the Philos locking plate system. Method: Between March 2003 and October 2004 we prospectively reviewed 24 of 26 patients with proximal humerus fractures treated with a Philos plate. The mean follow-up time was 12 months and the mean age of patients was 57 years. Six patients had four-part proximal humerus fractures, 11 patients had three-part proximal humerus fractures, and nine patients had two-part proximal humerus fractures. Clinical evaluation was performed using the University of California at Los Angeles (UCLA) criteria. Results: The mean UCLA score was 30 points (17-34). All fractures showed union. Three patients showed fracture union at varus position. The mean UCLA score for these patients was 27 points. Conclusion: Osteosynthesis with Philos plate provides a stable fixation method with good functional outcome. PMID:26998460

  6. Maxus challenges fracture techniques, brings in the best wells in 20 years

    SciTech Connect

    Lyle, D.

    1995-10-01

    Combining a look at old ideas and new techniques gave Maxus a string of better Texas Panhandle wells. This report describes the results of an analysis performed utilizing the program FRACPRO which has real time analysis capabilities. The analysis indicated poor proppant placement.

  7. WHAT ABOUT WHEN SUB-SLAB DEPRESSURIZATION DOESN'T WORK WELL?

    EPA Science Inventory

    The paper discusses the mitigation of radon levels in basementhouses when sub-slab depressurization (SSD), a widely usedmitigation technique, is not a viable option. or example, in somehouses the slab is poured directly on the soil, resulting inpoor-to-nonexistent communication u...

  8. How mantle slabs drive plate tectonics.

    PubMed

    Conrad, Clinton P; Lithgow-Bertelloni, Carolina

    2002-10-01

    The gravitational pull of subducted slabs is thought to drive the motions of Earth's tectonic plates, but the coupling between slabs and plates is not well established. If a slab is mechanically attached to a subducting plate, it can exert a direct pull on the plate. Alternatively, a detached slab may drive a plate by exciting flow in the mantle that exerts a shear traction on the base of the plate. From the geologic history of subduction, we estimated the relative importance of "pull" versus "suction" for the present-day plates. Observed plate motions are best predicted if slabs in the upper mantle are attached to plates and generate slab pull forces that account for about half of the total driving force on plates. Slabs in the lower mantle are supported by viscous mantle forces and drive plates through slab suction. PMID:12364804

  9. Biomechanical study in polyurethane mandibles of different metal plates and internal fixation techniques, employed in mandibular angle fractures.

    PubMed

    Semeghini Guastaldi, Fernando Pozzi; Hochuli-Vieira, Eduardo; Guastaldi, Antonio Carlos

    2014-11-01

    The aim of this study was to perform a physicochemical and morphological characterization and compare the mechanical behavior of an experimental Ti-Mo alloy to the analogous metallic Ti-based fixation system, for mandibular angle fractures. Twenty-eight polyurethane mandibles were uniformly sectioned on the left angle. These were divided into 4 groups: group Eng 1P, one 2.0-mm plate and 4 screws 6 mm long; group Eng 2P, two 2.0-mm plates, the first fixed with 4 screws 6 mm long and the second with 4 screws 12 mm long. The same groups were created for the Ti-15Mo alloy. Each group was subjected to linear vertical loading at the first molar on the plated side in a mechanical testing unit. Means and standard deviations were compared with respect to statistical significance using ANOVA. The chemical composition of the Ti-15Mo alloy was close to the nominal value. The mapping of Mo and Ti showed a homogeneous distribution. SEM of the screw revealed machining debris. For the plates, only the cpTi plate undergoes a surface treatment. The metallographic analysis reveals granular microstructure, from the thermomechanical trials. A statistically significant difference was found (P < 0.05) when the comparison between both internal fixation techniques was performed. The 2P technique showed better mechanical behavior than 1P. PMID:25340696

  10. Nose fracture

    MedlinePlus

    Fracture of the nose; Broken nose; Nasal fracture; Nasal bone fracture; Nasal septal fracture ... A fractured nose is the most common fracture of the face. It usually occurs after an injury and often occurs with ...

  11. Elbow hemiarthroplasty for the management of distal humeral fractures: current technique, indications and results.

    PubMed

    Phadnis, Joideep; Watts, Adam C; Bain, Gregory I

    2016-07-01

    There has been a growing recent interest in the use of elbow hemiarthroplasty for the treatment of distal humeral trauma in select patients. However, the current available evidence regarding outcome after elbow hemiarthroplasty is limited to case series and biomechanical data. Consequently, the procedure remains unfamiliar to many surgeons. The aim of the present review is to outline the evidence regarding elbow hemiarthroplasty and to use this, along with the author's experience, to better describe the indications, surgical technique and outcomes after this procedure. PMID:27583016

  12. Reattachment of a fractured fragment with relined fiber post using indirect technique: a case report

    PubMed Central

    Kim, Eun-Soo; Min, Kyung-San; Yu, Mi-Kyung

    2014-01-01

    Although fiber-reinforced posts have been widely used, they sometimes fail to obtain sufficient retention because of an extremely large canal space. To address this, several techniques have been introduced including relining of the fiber-reinforced posts. Here, we used a relined glass-fiber post to increase retention and fitness to the root canal in a crown reattachment case. The relining procedure was performed by using an indirect method on the working cast. This case also highlights the esthetic concerns regarding dehydration of the attached crown fragment. PMID:25383353

  13. Elbow hemiarthroplasty for the management of distal humeral fractures: current technique, indications and results

    PubMed Central

    Watts, Adam C; Bain, Gregory I

    2016-01-01

    There has been a growing recent interest in the use of elbow hemiarthroplasty for the treatment of distal humeral trauma in select patients. However, the current available evidence regarding outcome after elbow hemiarthroplasty is limited to case series and biomechanical data. Consequently, the procedure remains unfamiliar to many surgeons. The aim of the present review is to outline the evidence regarding elbow hemiarthroplasty and to use this, along with the author’s experience, to better describe the indications, surgical technique and outcomes after this procedure.

  14. Effects of triggering mechanism on snow avalanche slope angles and slab depths from field data

    NASA Astrophysics Data System (ADS)

    McClung, David M.

    2013-04-01

    Field data from snow avalanche fracture lines for slope angle and slab depth (measured perpendicular to the weak layer) were analyzed for different triggering mechanisms. For slope angle, the results showed that the same probability density function (pdf) (of log-logistic type) and range (25 - 55 degrees) apply independent of triggering mechanism. For slab depth, the same pdf (generalized extreme value) applies independent of triggering mechanism. For both slope angle and slab depth, the data skewness differentiated between triggering mechanism and increased with applied triggering load. For slope angle, skewness is lowest for natural triggering by snow loads and highest for triggering from human intervention. For slab depth, the skewness is lowest for natural triggering and highest for a mix of triggers including explosive control with skier triggering being intermediate. The results reveal the effects of triggering mechanism which are important for risk analyses and to guide avalanche forecasting.

  15. Skull fracture

    MedlinePlus

    Basilar skull fracture; Depressed skull fracture; Linear skull fracture ... Skull fractures may occur with head injuries . The skull provides good protection for the brain. However, a severe impact ...

  16. Optical distortions in end-pumped zigzag slab lasers.

    PubMed

    Tang, Bing; Zhou, Tangjian; Wang, Dan; Li, Mi

    2015-04-01

    Ray tracing is performed to investigate the optical distortions in the end-pumped, zigzag slab. Optical path differences caused by temperature, slab deformation, and stress birefringence are calculated under uniform pumping; the results show a steep edge in the width dimension and a thermal lens with an effective focal length as short as several meters in the thickness dimension. Dependence of depolarization on total internal reflection phase retardance as well as the slab's cut angle is studied by the Jones matrix technique; results show that although at the pumping power of 10 kW, the mean depolarization of the 2.5  mm×30  mm×150.2  mm Nd:YAG slab is generally below 3%, and it increases rapidly with pumping power. Besides, for the 0°- or 60°-cut slab, an optimal phase retardance range of 5° to 13° exists, in which the depolarization loss can be lower than 0.5%. Finally, experiments on temperature and depolarization measurements verify the numerical results. PMID:25967178

  17. Search for deep slabs in the Northwest Pacific mantle.

    PubMed

    Zhou, H W; Anderson, D L

    1989-11-01

    A residual sphere is formed by projecting seismic ray travel-time anomalies, relative to a reference Earth model, onto an imaginary sphere around an earthquake. Any dominant slab-like fast band can be determined with spherical harmonic expansion. The technique is useful in detecting trends associated with high-velocity slabs beneath deep earthquakes after deep-mantle and near-receiver effects are removed. Two types of corrections are used. The first uses a tomographic global mantle model; the second uses teleseismic station averages of residuals from many events over a large area centered on the events of interest. Under the Mariana, Izu-Bonin, and Japan trenches, the dominant fast bands are generally consistent with seismicity trends. The results are unstable and differ from the seismicity trend for Kurile events. The predominant fast band for most deep earthquakes under Japan is subhorizontal rather than near vertical. We find little support for the deep slab penetration hypothesis. PMID:16594080

  18. Seismicity and structure in central Mexico: Evidence for a possible slab tear in the South Cocos plate

    NASA Astrophysics Data System (ADS)

    Dougherty, Sara L.; Clayton, Robert W.

    2014-04-01

    The morphology of the transition from flat to normal subduction in eastern central Mexico is explored using intraslab earthquakes recorded by temporary and permanent regional seismic arrays. Observations of a sharp transition in slab dip near the abrupt end of the Trans-Mexican Volcanic Belt (TMVB) suggest a possible slab tear located within the subducted South Cocos plate. The eastern lateral extent of a thin ultra-slow velocity layer (USL) imaged atop the Cocos slab in recent studies along the Meso America Subduction Experiment array is examined here using additional data. We find an end to this USL which is coincident with the western boundary of a zone of decreased seismicity and the end of the TMVB near the sharp transition in slab dip. Waveform modeling of the 2-D structure in this region using a finite difference algorithm provides constraints on the velocity and geometry of the slab's seismic structure and confirms the location of the USL. Analysis of intraslab seismicity patterns reveals clustering, sudden increase in depth, variable focal mechanism orientations and faulting types, and alignment of source mechanisms along the sharp transition in slab dip. The seismicity and structural evidence suggests a possible tear in the South Cocos slab. This potential tear, together with the tear along the Orozco Fracture Zone to the northwest, indicates a slab rollback mechanism in which separate slab segments move independently, allowing for mantle flow between the segments.

  19. COMBINING A NEW 3-D SEISMIC S-WAVE PROPAGATION ANALYSIS FOR REMOTE FRACTURE DETECTION WITH A ROBUST SUBSURFACE MICROFRACTURE-BASED VERIFICATION TECHNIQUE

    SciTech Connect

    Bob Hardage; M.M. Backus; M.V. DeAngelo; R.J. Graebner; S.E. Laubach; Paul Murray

    2004-02-01

    Fractures within the producing reservoirs at McElroy Field could not be studied with the industry-provided 3C3D seismic data used as a cost-sharing contribution in this study. The signal-to-noise character of the converted-SV data across the targeted reservoirs in these contributed data was not adequate for interpreting azimuth-dependent data effects. After illustrating the low signal quality of the converted-SV data at McElroy Field, the seismic portion of this report abandons the McElroy study site and defers to 3C3D seismic data acquired across a different fractured carbonate reservoir system to illustrate how 3C3D seismic data can provide useful information about fracture systems. Using these latter data, we illustrate how fast-S and slow-S data effects can be analyzed in the prestack domain to recognize fracture azimuth, and then demonstrate how fast-S and slow-S data volumes can be analyzed in the poststack domain to estimate fracture intensity. In the geologic portion of the report, we analyze published regional stress data near McElroy Field and numerous formation multi-imager (FMI) logs acquired across McElroy to develop possible fracture models for the McElroy system. Regional stress data imply a fracture orientation different from the orientations observed in most of the FMI logs. This report culminates Phase 2 of the study, ''Combining a New 3-D Seismic S-Wave Propagation Analysis for Remote Fracture Detection with a Robust Subsurface Microfracture-Based Verification Technique''. Phase 3 will not be initiated because wells were to be drilled in Phase 3 of the project to verify the validity of fracture-orientation maps and fracture-intensity maps produced in Phase 2. Such maps cannot be made across McElroy Field because of the limitations of the available 3C3D seismic data at the depth level of the reservoir target.

  20. Dermal Fenestration With Negative Pressure Wound Therapy: A Technique for Managing Soft Tissue Injuries Associated With High-Energy Complex Foot Fractures.

    PubMed

    Poon, Henrietta; Le Cocq, Heather; Mountain, Alistair J; Sargeant, Ian D

    2016-01-01

    Military casualties can sustain complex foot fractures from blast incidents. This frequently involves the calcaneum and is commonly associated with mid-foot fracture dislocations. The foot is at risk of both compartment syndrome and the development of fracture blisters after such injuries. The amount of energy transfer and the environment in which the injury was sustained also predispose patients to potential skin necrosis and deep infection. Decompression of the compartments is a part of accepted practice in civilian trauma to reduce the risk of complications associated with significant soft tissue swelling. The traditional methods of foot fasciotomy, however, are not without significant complications. We report a simple technique of dermal fenestration combined with the use of negative pressure wound therapy, which aims to preserve the skin integrity of the foot without resorting to formal fasciotomy. PMID:26443232

  1. DESIGN AND TESTING OF SUB-SLAB DEPRESSURIZATION FOR RADON MITIGATION IN NORTH FLORIDA HOUSES - PART I. PERFORMANCE AND DURABILITY - VOLUME 2. DATA APPENDICES

    EPA Science Inventory

    The report gives results of a demonstration/research project to evaluate sub-slab depressurization (SSD) techniques for radon mitigation in North Florida where the housing stock is primarily slab-on-grade and the sub-slab medium typically consists of native soil and sand. Objecti...

  2. DESIGN AND TESTING OF SUB-SLAB DEPRESSURIZATION FOR RADON MITIGATION IN NORTH FLORIDA HOUSES - PART I. PERFORMANCE AND DURABILITY - VOLUME 1. TECHNICAL REPORT

    EPA Science Inventory

    The report gives results of a demonstration/research project to evaluate sub-slab depressurization (SSD) techniques for radon mitigation in North Florida where the housing stock is primarily slab-on-grade and the sub-slab medium typically consists of native soil and sand. Objecti...

  3. Treatment of close-range, low-velocity gunshot fractures of tibia and femur diaphysis with consecutive compression-distraction technique: a report of 11 cases.

    PubMed

    Ateşalp, A Sabri; Kömürcü, Mahmut; Demiralp, Bahtiyar; Bek, Dogan; Oğuz, Erbil; Yanmiş, Ibrahim

    2004-01-01

    Lower extremity injuries secondary to close-range, low-velocity gunshot wounds are frequently seen in both civilian and military populations. A close-range, low-velocity injury produces high energy and often results in comminuted and complicated fractures with significant morbidity. In this study, four femoral, four tibial, and three combined tibia and fibular comminuted diaphyseal fractures secondary to close-range, low-velocity gunshot wounds in 11 military personnel were treated with debridement followed by compression-distraction lengthening using a circular external fixator frame. Fracture union was obtained in all without significant major complications. Fracture consolidation occurred at a mean of 3.5 months. At follow-up of 46.8 months, there were no delayed unions, nonunions, or malunions. Minor complications included four pin-tract infections and knee flexion limitation in two femur fractures. Osteomyelitis and deep soft tissue infection were not observed. This technique provided an alternative to casting, open reduction internal fixation, or intermedullary fixation with an acceptable complication rate. PMID:15281409

  4. Vibration characteristics of floating slab track

    NASA Astrophysics Data System (ADS)

    Kuo, Chen-Ming; Huang, Cheng-Hao; Chen, Yi-Yi

    2008-11-01

    Coupled equilibrium equations of suspended wheels and floating slab track system were solved with the fourth-order Runge-Kutta method to obtain the deflections, vibration velocities, and wheel-rail contact forces. The program was validated through several aspects. Cases with various vehicle speed, slab mass, and stiffness of slab bearing were analyzed to reveal the effects of slab bearing on track responses. The correlation between wheel-rail resonance and train speed was also discussed. It was found that rail deflections increase significantly as train speed increases. Although large slab mass may lower tuning frequency, it could also result in higher wheel-rail contact force and rail deflections. The floating slab track is effective in isolating loading above 10 Hz, which might present in some railway sections with irregularities. Adopting floating slab track for vibration control for environment along the railway may cause concerns about ride quality and track damages.

  5. Seismic-reflection technique used to verify shallow rebound fracture zones in the Pierre Shale of South Dakota ( USA).

    USGS Publications Warehouse

    Nichols, T.C., Jr.; King, K.W.; Collins, D.S.; Williams, R.A.

    1988-01-01

    Shallow seismic-reflection data are presented to demonstrate their usefulness for locating and showing the continuity and lateral extent of rebound fracture zones in the Pierre Shale. Rebound fracture zones, identified in boreholes near Hayes, South Dakota, have variable depth, thickness, and character, thus making questionable the correlation of these zones between holes. Thus, the subsequent determination of dip and of continuity of the zones is somewhat tenuous, especially if the fracture characteristics change significantly between holes. Once rebound fracture zones have been identified and located by borehole geotechnical and geologic data, seismic profiles can reveal the extent and geometry of fractures in these zones, thus providing valuable preconstruction information without the cost of additional drilling.-Authors

  6. The effect of amount of lost tooth structure and restorative technique on fracture resistance of endodontically treated premolars

    PubMed Central

    Bassir, Mahshid Mohammadi; Labibzadeh, Akram; Mollaverdi, Fatemeh

    2013-01-01

    Aim: Endodontic treatment generally reduces the fracture resistance of teeth. The purpose of this study was to evaluate the fracture resistance and the mode of fracture of endodontically treated human premolars with different amounts of remaining tooth structure. Materials and Methods: Seventy non-carious human premolars were randomly assigned into 7 groups. Group 1 (ST) did not receive any preparation. The teeth in groups 2-7 received root canal treatment and different preparations. Group 2 (MO-NF): Mesio-occlusal preparation without filling; Group 3 (MOD-NF): Mesio-occluso-distal preparation without filling; Group 4 (MO-F): Mesio-occlusal preparation with direct composite restoration (Z250); Group 5 (MOD-F): Mesio-occluso-distal preparation with direct composite restoration (Z250); Group 6 (CC-D): Mesio-occluso-distal preparation with cusp reduction and direct composite restoration (Z250); Group 7 (CC-InD): Mesio-occluso-distal preparation with cusp reduction and indirect composite restoration (Gradia GC). The fracture resistance (N) was assessed under compressive load in a universal testing machine (Zwick) perpendicular to the occlusal surface at a cross-head speed of 1 mm/min, and the mode of fracture was assessed under stereomicroscope. Statistical analysis: Data was analyzed by Kruskal – Wallis and Mann – Whitney tests and the mode of fracture was analyzed by Chi-square test (P < 0.05). Results: Statistical analysis showed that MO and MOD cavity preparations significantly reduced the fracture resistance of sound teeth. Direct composite restorations can improve the fracture resistance, and Groups 7 and 6 presented the highest fracture resistance values. Conclusions: Teeth with adhesive restorations showed significantly higher fracture resistance values as compared with the non-restored ones. PMID:24082569

  7. Surgical Fixation of Sternal Fractures: Preoperative Planning and a Safe Surgical Technique Using Locked Titanium Plates and Depth Limited Drilling

    PubMed Central

    Schulz-Drost, Stefan; Oppel, Pascal; Grupp, Sina; Schmitt, Sonja; Carbon, Roman Th.; Mauerer, Andreas; Hennig, Friedrich F.; Buder, Thomas

    2015-01-01

    Different ways to stabilize a sternal fracture are described in literature. Respecting different mechanisms of trauma such as the direct impact to the anterior chest wall or the flexion-compression injury of the trunk, there is a need to retain each sternal fragment in the correct position while neutralizing shearing forces to the sternum. Anterior sternal plating provides the best stability and is therefore increasingly used in most cases. However, many surgeons are reluctant to perform sternal osteosynthesis due to possible complications such as difficulties in preoperative planning, severe injuries to mediastinal organs, or failure of the performed method. This manuscript describes one possible safe way to stabilize different types of sternal fractures in a step by step guidance for anterior sternal plating using low profile locking titanium plates. Before surgical treatment, a detailed survey of the patient and a three dimensional reconstructed computed tomography is taken out to get detailed information of the fracture’s morphology. The surgical approach is usually a midline incision. Its position can be described by measuring the distance from upper sternal edge to the fracture and its length can be approximated by the summation of 60 mm for the basis incision, the thickness of presternal soft tissue and the greatest distance between the fragments in case of multiple fractures. Performing subperiosteal dissection along the sternum while reducing the fracture, using depth limited drilling, and fixing the plates prevents injuries to mediastinal organs and vessels. Transverse fractures and oblique fractures at the corpus sterni are plated longitudinally, whereas oblique fractures of manubrium, sternocostal separation and any longitudinally fracture needs to be stabilized by a transverse plate from rib to sternum to rib. Usually the high convenience of a patient is seen during follow up as well as a precise reconstruction of the sternal morphology. PMID

  8. Mantle flow and dynamic topography associated with slab window opening: Insights from laboratory models

    NASA Astrophysics Data System (ADS)

    Guillaume, Benjamin; Moroni, Monica; Funiciello, Francesca; Martinod, Joseph; Faccenna, Claudio

    2010-12-01

    We present dynamically self-consistent mantle-scale laboratory models that have been conducted to improve our understanding of the influence of slab window opening on subduction dynamics, mantle flow and associated dynamic topography over geological time scales. The adopted setup consists of a two-layer linearly viscous system simulating the subduction of a fixed plate of silicone (lithosphere) under negative buoyancy in a viscous layer of glucose syrup (mantle). Our experimental setting is also characterized by a constant-width rectangular window located at the center of a laterally confined slab, modeling the case of the interaction of a trench-parallel spreading ridge with a wide subduction zone. We found that the opening of a slab window does not produce consistent changes of the geometry and the kinematics of the slab. On the contrary, slab-induced mantle circulation, quantified both in the vertical and horizontal sections using the Feature Tracking image analysis technique, is strongly modified. In particular, rollback subduction and the opening of the slab window generate a complex mantle circulation pattern characterized by the presence of poloidal and toroidal components, with the importance of each evolving according to kinematic stages. Mantle coming from the oceanic domain floods through the slab window, indenting the supra-slab mantle zone and producing its deformation without any mixing between mantle portions. The opening of the slab window and the upwelling of sub-slab mantle produce a regional-scale non-isostatic topographic uplift of the overriding plate that would correspond to values ranging between ca. 1 and 5 km in nature. Assuming that our modeling results can be representative of the natural behavior of subduction zones, we compared them to the tectonics and volcanism of the Patagonian subduction zone. We found that the anomalous backarc volcanism that has been developing since the middle Miocene could result from the lateral flow of sub-slab

  9. Wet or dry bandages for plaster back-slabs?

    PubMed

    Baliga, Santosh; Finlayson, D

    2012-12-01

    Cotton crêpe and stretch bandages are commonly used in back-slabs and casts in orthopaedic practice. In theory they allow swelling to occur after injury while splinting the fracture. The application of a wet bandage prevents the Plaster-of-Paris (POP) setting too rapidly, giving time to apply a mould or attain correct limb position. However, we hypothesised that a wet bandage contracts upon drying and may cause constriction of the splint. This study aimed at determining whether there was any significant change in length of commonly used bandages when wet as well as any further change when left to dry again. Two types of bandage were evaluated. 250 mm strips of bandage were dipped into water, gently squeezed and laid flat on a bench. The bandage was then immediately measured in length. The strips were then left to dry and re-measured. This experimental study shows that both cotton crepe and cling significantly shrink by around 7% when wet. This phenomenon has the potential to significantly increase the pressure exerted on the limb by a back-slab. We speculate that the application of wet bandages is why some back-slabs may need released. It is therefore recommended that bandages should be applied only in the dry form. PMID:22079697

  10. Preface: Deep Slab and Mantle Dynamics

    NASA Astrophysics Data System (ADS)

    Suetsugu, Daisuke; Bina, Craig R.; Inoue, Toru; Wiens, Douglas A.

    2010-11-01

    We are pleased to publish this special issue of the journal Physics of the Earth and Planetary Interiors entitled "Deep Slab and Mantle Dynamics". This issue is an outgrowth of the international symposium "Deep Slab and Mantle Dynamics", which was held on February 25-27, 2009, in Kyoto, Japan. This symposium was organized by the "Stagnant Slab Project" (SSP) research group to present the results of the 5-year project and to facilitate intensive discussion with well-known international researchers in related fields. The SSP and the symposium were supported by a Grant-in-Aid for Scientific Research (16075101) from the Ministry of Education, Culture, Sports, Science and Technology of the Japanese Government. In the symposium, key issues discussed by participants included: transportation of water into the deep mantle and its role in slab-related dynamics; observational and experimental constraints on deep slab properties and the slab environment; modeling of slab stagnation to constrain its mechanisms in comparison with observational and experimental data; observational, experimental and modeling constraints on the fate of stagnant slabs; eventual accumulation of stagnant slabs on the core-mantle boundary and its geodynamic implications. This special issue is a collection of papers presented in the symposium and other papers related to the subject of the symposium. The collected papers provide an overview of the wide range of multidisciplinary studies of mantle dynamics, particularly in the context of subduction, stagnation, and the fate of deep slabs.

  11. Age-dependent fracture risk in hip revisions with radial impaction grafting technique: a 5-10 year medium-term follow-up study.

    PubMed

    Chomrikh, Laila; Gebuhr, Peter; Bierling, Roelf; Lind, Ulla; Zwart, Hendrik J J

    2014-02-01

    Radial impaction grafting (RIG) potentially improves the durability and reliability of cementing the femoral components in revision total hip arthroplasty (THA). In this multicenter, prospective study, 88 revision THAs (87 patients) with RIG technique were performed. The average follow-up time was 7.0 years (range, 5.0-10.2). There were 14 femur fractures: 2 intraoperative, 5 within 3 months after surgery, and 7 later in the postoperative stage (range, 5-84 months). Sixteen patients were lost to follow-up and 20 died without stem re-revision. None of the patients have been re-revised for any reason during follow-up. Age was observed to be a significant factor for determining fracture risk. In conclusion, RIG can be considered a reliable surgical technique, especially for younger patients. PMID:23891061

  12. Infraorbital nerve transpositioning into orbital floor: a modified technique to minimize nerve injury following zygomaticomaxillary complex fractures

    PubMed Central

    Kotrashetti, Sharadindu Mahadevappa; Kale, Tejraj Pundalik; Bhandage, Supriya

    2015-01-01

    Objectives Transpositioning of the inferior alveolar nerve to prevent injury in lower jaw has been advocated for orthognathic, pre-prosthetic and for implant placement procedures. However, the concept of infra-orbital nerve repositioning in cases of mid-face fractures remains unexplored. The infraorbital nerve may be involved in trauma to the zygomatic complex which often results in sensory disturbance of the area innervated by it. Ten patients with infraorbital nerve entrapment were treated in similar way at our maxillofacial surgery centre. Materials and Methods In this article we are reporting three cases of zygomatico-maxillary complex fracture in which intra-operative repositioning of infra-orbital nerve into the orbital floor was done. This was done to release the nerve from fractured segments and to reduce the postoperative neural complications, to gain better access to fracture site and ease in plate fixation. This procedure also decompresses the nerve which releases it off the soft tissue entrapment caused due to trauma and the organized clot at the fractured site. Results There was no evidence of sensory disturbance during their three month follow-up in any of the patient. Conclusion Infraorbital nerve transposition is very effective in preventing paresthesia in patients which fracture line involving the infraorbital nerve. PMID:25922818

  13. Stabilization of Volar Ulnar Rim Fractures of the Distal Radius: Current Techniques and Review of the Literature.

    PubMed

    O'Shaughnessy, Maureen A; Shin, Alexander Y; Kakar, Sanjeev

    2016-05-01

    Background Distal radius fractures involving the lunate facet can be challenging to manage. Reports have shown the volar carpal subluxation/dislocation that can occur if the facet is not appropriately stabilized. Literature Review Recent emphasis in the literature has underscored the difficulty in managing this fracture fragment, suggesting standard volar plates may not be able to adequately stabilize the fragment. This article reviews the current literature with a special emphasis on fixation with a specifically designed fragment-specific hook plate to secure the lunate facet. Case Description An extended flexor carpi radialis volar approach was made which allows access to the distal volar ulnar fracture fragment. Once provisionally stabilized with Kirschner wire fixation, a volar hook plate was applied to capture this fragment. Additional fracture stabilization was used as deemed necessary to stabilize the remaining distal radius fracture. Clinical Relevance The volar marginal rim fragment remains a challenge in distal radius fracture management. Use of a hook plate to address the volar ulnar corner allows for stable fixation without loss of reduction at intermediate-term follow-up. PMID:27104076

  14. Numerical Models of Subduction and Slab Detachment: Placing a Lower Bound on the Strength of Slabs

    NASA Astrophysics Data System (ADS)

    Billen, M. I.; Andrews, E.

    2007-12-01

    Subduction provides the main driving force for the motion of tectonic plates at the Earth's surface through slab- pull and sinking-induced flow in the surrounding mantle. The ability of the slab to directly transmit slab-pull forces to the tectonic plate at the surface depends on the minimum strength and rheology (e.g., viscous, plastic) of the slab. Previous models have shown that observations including the state of stress in slabs, dynamic topography and the geoid above slabs, the evolution of slab and the kinematic history of subduction can be well-matched by a variety of models with either low viscosity (i.e., 100-1,000 times more viscous than the surrounding mantle) or high viscosity slabs (i.e., more than 10,000 times more viscous than the surrounding mantle). However, in many of the models in which a good match to observations is found for low viscosity slabs, the maximum slab viscosity is imposed as a cut-off value, which forces the entire slab to have a more or less uniform viscosity independent of strain-rate or stress magnitude, rather than a plastic yielding-type rheology. We present numerical models demonstrating that when the non-Newtonian viscosity of the upper mantle and plastic yielding behavior of slabs are taken into account, the minimum yield strength that allows for continuous subduction is approximately 300- 500 MPa, which leads to high viscosity slabs with some localized lower viscosity regions. A yield stress of 10-100 MPa is required to form uniformly low viscosity slabs, but these slabs detach from the subducting plate, due to localized weakening, when the slab reaches a length of 200-300 km, even when subduction is facilitated by a low viscosity shear zone and kinematically-imposed surface velocities. In contrast, detachment of higher strength slabs in fully-dynamic models only occurs when the shear zone is removed and prevents further subduction.

  15. Comparative Evaluation of Fracture Resistance of Endodontically Treated Teeth Obturated with Resin Based Adhesive Sealers with Conventional Obturation Technique: An In vitro Study

    PubMed Central

    Langalia, Akshay K; Dave, Bela; Patel, Neeta; Thakkar, Viral; Sheth, Sona; Parekh, Vaishali

    2015-01-01

    Background: To compare fracture resistance of endodontically treated teeth obturated with different resin-based adhesive sealers with a conventional obturation technique. Materials and Methods: A total of 60 Single canaled teeth were divided into five groups. The first group was taken as a negative control. The rest of the groups were shaped using ProFile rotary files (Dentsply Maillefer, Ballaigues, Switzerland). The second group was obturated with gutta-percha and a ZOE-based sealer Endoflas FS (Sanlor Dental Products, USA). The third group was obturated with gutta-percha and an epoxy-based sealer AH Plus (Dentsply, DeTrey, Germany). The fourth group was obturated with Resilon (Pentron Clinical Technologies, Wallingford, CT) and RealSeal sealer (Pentron Clinical Technologies). The fifth group was obturated with EndoREZ points and EndoREZ sealer (both from Ultradent, South Jordan, UT). Roots were then embedded into acrylic blocks and were then fixed into a material testing system and loaded with a stainless steel pin with a crosshead speed of 5 mm/min until fracture. The load at which the specimen fractured was recorded in Newtons. Results: It was found that forces at fracture were statistically significant for the newer resin systems, Resilon, and EndoREZ. Conclusion: It was concluded that roots obturated with newer resin systems (Resilon and EndoREZ) enhanced the root strength almost up to the level of the intact roots. PMID:25859099

  16. Retrograde Intramedullary Nailing with a Blocking Pin Technique for Reduction of Periprosthetic Supracondylar Femoral Fracture after Total Knee Arthroplasty: Technical Note with a Compatibility Chart of the Nail to Femoral Component

    PubMed Central

    Hamada, Daisuke; Takasago, Tomoya; Tsutsui, Takahiko; Suzue, Naoto; Sairyo, Koichi

    2014-01-01

    Periprosthetic fractures after total knee arthroplasty (TKA) present a clear management challenge, and retrograde intramedullary nails have recently gained widespread acceptance in treatment of these fractures. In two cases, we found a blocking screw technique, first reported by Krettek et al., was useful in the reduction of the fractures. Both patients attained preinjury mobility after intramedullary nailing. Moreover, we present a chart summarizing the notch designs of various femoral components because some prosthetic knee designs are not amenable to retrograde nailing. We hope this will be helpful in determining indications for retrograde nailing in periprosthetic fractures after TKA. PMID:25574411

  17. Evaluation of proximal femoral locking plate in unstable extracapsular proximal femoral fractures: Surgical technique & mid term follow up results☆

    PubMed Central

    Kumar, Nishikant; Kataria, Himanshu; Yadav, Chandrashekhar; Gadagoli, Bharath S.; Raj, Rishi

    2014-01-01

    Background Stable trochanteric femur fractures can be treated successfully with conventional implants such as sliding hip screw, cephalomedullary nails, angular blade plates. However comminuted and unstable inter or subtrochanteric fractures with or without osteoporosis are challenging & prone to complications. The PF-LCP is a new implant that allows angular stability by creating fixed angle block for treatment of complex, comminuted proximal femoral fractures. Method We reviewed 30 patients with unstable inter or subtrochanteric fractures, which were stabilized with PF-LCP. Mean age of patient was 65 years, and average operative time was 80 min. Patients were followed up for a period of 3 years (June 2010–June 2013). Patients were examined regularly at 3 weekly interval for signs of union (radiological & clinical), varus collapse (neck-shaft angle), limb shortening, and hardware failure. Result All patients showed signs of union at an average of 9 weeks (8–10 weeks), with minimum varus collapse (<10°), & no limb shortening and hardware failure. Results were analysed using IOWA (Larson) hip scoring. Average IOWA hip score was 77.5. Conclusion PF-LCP represents a feasible alternative for treatment of unstable inter- or subtrochanteric fractures. PMID:25983487

  18. Dynamic uplift during slab flattening

    NASA Astrophysics Data System (ADS)

    Dávila, Federico M.; Lithgow-Bertelloni, Carolina

    2015-09-01

    Subduction exerts a strong control on surface topography and is the main cause of large vertical motions in continents, including past events of large-scale marine flooding and tilting. The mechanism is dynamic deflection: the sinking of dense subducted lithosphere gives rise to stresses that directly pull down the surface. Here we show that subduction does not always lead to downward deflections of the Earth's surface. Subduction of young lithosphere at shallow angles (flat subduction) leaves it neutrally or even positively buoyant with respect to underlying mantle because the lithosphere is relatively warm compared with older lithosphere, and because the thickened and hence drier oceanic crust does not undergo the transformation of basalt to denser eclogite. Accounting for neutrally buoyant flat segments along with large variations in slab morphology in the South American subduction zone explains along-strike and temporal changes in dynamic topography observed in the geologic record since the beginning of the Cenozoic. Our results show that the transition from normal subduction to slab flattening generates dynamic uplift, preventing back-arc marine flooding.

  19. Subducting Slabs: Jellyfishes in the Earth's Mantle

    NASA Astrophysics Data System (ADS)

    Loiselet, C.; Braun, J.; Husson, L.; Le Carlier de Veslud, C.; Thieulot, C.; Yamato, P.; Grujic, D.

    2010-12-01

    The constantly improving resolution of geophysical data, seismic tomography and seismicity in particular, shows that the lithosphere does not subduct as a slab of uniform thickness but is rather thinned in the upper mantle and thickened around the transition zone between the upper and lower mantle. This observation has traditionally been interpreted as evidence for the buckling and piling of slabs at the boundary between the upper and lower mantle, where a strong contrast in viscosity may exist and cause resistance to the penetration of slabs into the lower mantle. The distribution and character of seismicity reveal, however, that slabs undergo vertical extension in the upper mantle and compression near the transition zone. In this paper, we demonstrate that during the subduction process, the shape of low viscosity slabs (1 to 100 times more viscous than the surrounding mantle) evolves toward an inverted plume shape that we coin jellyfish. Results of a 3D numerical model show that the leading tip of slabs deform toward a rounded head skirted by lateral tentacles that emerge from the sides of the jellyfish head. The head is linked to the body of the subducting slab by a thin tail. A complete parametric study reveals that subducting slabs may achieve a variety of shapes, in good agreement with the diversity of natural slab shapes evidenced by seismic tomography. Our work also suggests that the slab to mantle viscosity ratio in the Earth is most likely to be lower than 100. However, the sensitivity of slab shapes to upper and lower mantle viscosities and densities, which remain poorly constrained by independent evidence, precludes any systematic deciphering of the observations.

  20. Subducting slabs: Jellyfishes in the Earth's mantle

    NASA Astrophysics Data System (ADS)

    Loiselet, Christelle; Braun, Jean; Husson, Laurent; Le Carlier de Veslud, Christian; Thieulot, Cedric; Yamato, Philippe; Grujic, Djordje

    2010-08-01

    The constantly improving resolution of geophysical data, seismic tomography and seismicity in particular, shows that the lithosphere does not subduct as a slab of uniform thickness but is rather thinned in the upper mantle and thickened around the transition zone between the upper and lower mantle. This observation has traditionally been interpreted as evidence for the buckling and piling of slabs at the boundary between the upper and lower mantle, where a strong contrast in viscosity may exist and cause resistance to the penetration of slabs into the lower mantle. The distribution and character of seismicity reveal, however, that slabs undergo vertical extension in the upper mantle and compression near the transition zone. In this paper, we demonstrate that during the subduction process, the shape of low viscosity slabs (1 to 100 times more viscous than the surrounding mantle) evolves toward an inverted plume shape that we coin jellyfish. Results of a 3D numerical model show that the leading tip of slabs deform toward a rounded head skirted by lateral tentacles that emerge from the sides of the jellyfish head. The head is linked to the body of the subducting slab by a thin tail. A complete parametric study reveals that subducting slabs may achieve a variety of shapes, in good agreement with the diversity of natural slab shapes evidenced by seismic tomography. Our work also suggests that the slab to mantle viscosity ratio in the Earth is most likely to be lower than 100. However, the sensitivity of slab shapes to upper and lower mantle viscosities and densities, which remain poorly constrained by independent evidence, precludes any systematic deciphering of the observations.

  1. The effectiveness of the antegrade reamed technique: the experience and complications from 415 traumatic femoral shaft fractures

    PubMed Central

    Papadimitriou, George; Theodoratos, Gerasimos; Papanikolaou, Anastasios; Maris, John

    2009-01-01

    This retrospective study presents the experience gained through use of reamed femoral nails and reports results and respective complications. This study included 415 femur fractures (312 men and 101 women with a mean age of 27.8 years) that were treated from 1993 to 2004. The fractures were classified according to AO, and 74 open fractures were included and typed according to the Gustilo classification. Dynamic nailing was performed for nearly all type A fractures and static nailing for types B and C. After a mean follow-up of 1.5 years, union rate was 97.8%. The complications were: 9 non-unions, 14 delayed-unions, 4 torsional malunions, 6 limb length discrepancies (shortening) and 30 nerve pareses due to traction. Deep venous thrombosis (DVT) occurred below the knee in 4 patients, while there were recorded 3 pulmonary and 2 fat embolisms, 1 superficial and 1 deep infection. There were 28 broken screws identified postoperatively. Logistic regression analysis revealed that type B and C were associated with increased risk of complications, with respective odds ratios of 3.1 (95% CI = 1.3–7.2, P = 0.011) and 4.3 (95% CI = 1.8–10.3, P = 0.001) when compared to type A patterns. All patients returned to their activities in a mean time of 10 months. Intramedullary nailing is still the treatment of choice for femoral shaft fractures, but knowledge of potential complications and their association with certain fracture patterns is needed. PMID:19936887

  2. Outcomes After Fixation of Proximal Humerus (OTA Type 11) Fractures in the Elderly Patients Using Modern Techniques

    PubMed Central

    Shulman, Brandon S.; Ong, Crispin C.; Lee, James H.; Karia, Raj; Zuckerman, Joseph D.; Egol, Kenneth A.

    2013-01-01

    Purpose To investigate the effects of age on the clinical, functional, and radiographic outcomes of patients with proximal humerus fractures treated operatively with locking plates. Methods Between February 2003 and July 2012, all patients who sustained a proximal humerus fracture who presented to our institution were enrolled into a database. Patients were followed up at 1, 6, 12, 26, and 52 weeks postoperatively with physical examination and radiographs. Validated functional outcomes scores were collected at 6 and 12 months. Complications were recorded as they occurred. Statistical analysis was conducted to assess for functional, physical, or radiographic differences between patients age younger than 65 and patients age 65 or older. Results Of the 147 consecutive patients treated operatively for a proximal humerus fracture, 115 (78%) patients with an average follow-up of 16 months met the inclusion criteria for this study. The young cohort (patients < 65) included 70 patients with an average age of 53, whereas the elderly cohort (patients ≥ 65) included 45 patients with an average age of 73. The older cohort had significantly more women (P = .04), but there was no statistical difference in fracture type between the age groups. There were no differences in the radiographic measures of screw penetration, humeral head height, and neck-shaft angle between the age groups. There were no differences in physical examination scores between the age groups. There were no significant differences in functional outcomes or complication rates between the age groups. Conclusion Treating proximal humerus fractures operatively with locked plates can overcome the challenges of poor bone quality that often occur with increasing age. Age should not play a significant role in the decision-making process for treating proximal humerus fractures that would otherwise be indicated for surgical fixation. PMID:23936736

  3. Combined Orbital Floor and Medial Wall Fractures Involving the Inferomedial Strut: Repair Technique and Case Series Using Preshaped Porous Polyethylene/Titanium Implants

    PubMed Central

    Cho, Raymond I.; Davies, Brett W.

    2013-01-01

    Background Combined orbital floor and medial wall fractures can be technically challenging to repair, particularly when the inferomedial strut is involved. A surgical repair technique is described utilizing a single preshaped porous polyethylene/titanium implant to span both defects. Methods Retrospective interventional case series. Results Fracture repair was performed on 17 orbits (16 patients) between October 2009 and February 2012. Subsequent surgical revision was required in three cases (18%). Visual acuity was stable or improved in all cases. Of 7 patients with preoperative diplopia, 5 improved and 2 remained stable postoperatively, and there were no cases of new or worsened diplopia following surgery. Postoperative asymmetry in Hertel exophthalmometry averaged 1.0 mm (range 0 to 2 mm). Preoperatively, average orbital volume was 122.7% compared with control (range 109 to 147%, standard deviation [SD] 9.6), which improved to 100.3% postoperatively (range 92 to 110%, SD 5.7). The average decrease in orbital volume was 22.5% (range 10 to 54%, SD 11.4, p < 0.001). Conclusions With careful preoperative planning and meticulous surgical technique, combined orbital floor and medial wall fractures involving the inferomedial strut can be successfully repaired with a preshaped porous polyethylene/titanium implant through a transconjunctival/transcaruncular approach with inferior oblique disinsertion. PMID:24436754

  4. Evaluation of Stress Corrosion Cracking Susceptibility Using Fracture Mechanics Techniques, Part 1. [environmental tests of aluminum alloys, stainless steels, and titanium alloys

    NASA Technical Reports Server (NTRS)

    Sprowls, D. O.; Shumaker, M. B.; Walsh, J. D.; Coursen, J. W.

    1973-01-01

    Stress corrosion cracking (SSC) tests were performed on 13 aluminum alloys, 13 precipitation hardening stainless steels, and two titanium 6Al-4V alloy forgings to compare fracture mechanics techniques with the conventional smooth specimen procedures. Commercially fabricated plate and rolled or forged bars 2 to 2.5-in. thick were tested. Exposures were conducted outdoors in a seacoast atmosphere and in an inland industrial atmosphere to relate the accelerated tests with service type environments. With the fracture mechanics technique tests were made chiefly on bolt loaded fatigue precracked compact tension specimens of the type used for plane-strain fracture toughness tests. Additional tests of the aluminum alloy were performed on ring loaded compact tension specimens and on bolt loaded double cantilever beams. For the smooth specimen procedure 0.125-in. dia. tensile specimens were loaded axially in constant deformation type frames. For both aluminum and steel alloys comparative SCC growth rates obtained from tests of precracked specimens provide an additional useful characterization of the SCC behavior of an alloy.

  5. Finite-Element Analysis of a New Designed Miniplate which is Used via Intraoral Approach to the Mandible Angle Fracture: Comparison of the Different Fixation Techniques.

    PubMed

    Coskunses, Fatih Mehmet; Kocyigit, Ismail Doruk; Atil, Fethi; Tekin, Umut; Suer, Berkay Tolga; Tuz, Hakan Hifzi; Ozgul, Ozkan; Yagiz, Ayberk

    2015-07-01

    The mandible is the largest facial bone as well as the most commonly fractured bone in the maxillofacial region. Despite numerous studies conducted to identify optimal treatment modalities and plates configurations for intraoral and transoral approaches, no definitive conclusion has been reached. This study used finite element analysis (FEA) to assess 4 scenarios for treatment of an angle fracture (6-hole noncompression miniplate; 6-hole single plate/Champy's technique, 3D strut plate; 2 parallel 4-hole noncompression miniplates). Analysis included segmental displacement and Von Mises Stress evaluations of a 3D reconstruction of a human mandible. Von Mises Stress values for plates did not vary significantly among treatment groups. Moreover, no significant differences were observed in cumulative displacement of segments subjected to vertical and horizontal loads, with all treatment configurations demonstrating clinical acceptability. PMID:26091053

  6. Experimental trial on surgical treatment for transverse fractures of the proximal phalanx: technique using intramedullary conical compression screw versus lateral compression plate☆

    PubMed Central

    Ibanez, Daniel Schneider; Rodrigues, Fabio Lucas; Salviani, Rafael Salmeron; Roberto, Fernando Augusto Reginatto; Pengo Junior, Jose Roberto; Aita, Marcio Aurelio

    2015-01-01

    Objective To compare the mechanical parameters between two methods for stabilization through compression: 1.5 mm axial compression plate versus conical compression screw used as an intramedullary tutor. Methods Polyurethane models (Sawbone®) that simulated transverse fractures of the proximal phalanx were used. The models were divided into three groups: lateral plate, conical screw and no implant. Results Greater force was needed to result in fatigue in the synthesis using an intramedullary plate. Thus, this model was proven to be mechanically superior to the model with the lateral plate. Conclusion Stabilization using the Acutrak® screw for treating fractures in the model used in this trial presents mechanical results that are statistically significantly superior to those from the axial compression technique using the lateral plate (Aptus Hand®). PMID:26535195

  7. Talus fractures: surgical principles.

    PubMed

    Rush, Shannon M; Jennings, Meagan; Hamilton, Graham A

    2009-01-01

    Surgical treatment of talus fractures can challenge even the most skilled foot and ankle surgeon. Complicated fracture patterns combined with joint dislocation of variable degrees require accurate assessment, sound understanding of principles of fracture care, and broad command of internal fixation techniques needed for successful surgical care. Elimination of unnecessary soft tissue dissection, a low threshold for surgical reduction, liberal use of malleolar osteotomy to expose body fracture, and detailed attention to fracture reduction and joint alignment are critical to the success of treatment. Even with the best surgical care complications are common and seem to correlate with injury severity and open injuries. PMID:19121756

  8. The slab geometry laser. I - Theory

    NASA Technical Reports Server (NTRS)

    Eggleston, J. M.; Kane, T. J.; Kuhn, K.; Byer, R. L.; Unternahrer, J.

    1984-01-01

    Slab geometry solid-state lasers offer significant performance improvements over conventional rod-geometry lasers. A detailed theoretical description of the thermal, stress, and beam-propagation characteristics of a slab laser is presented. The analysis includes consideration of the effects of the zig-zag optical path, which eliminates thermal and stress focusing and reduces residual birefringence.

  9. Influence of core design, production technique, and material selection on fracture behavior of yttria-stabilized tetragonal zirconia polycrystal fixed dental prostheses produced using different multilayer techniques: split-file, over-pressing, and manually built-up veneers

    PubMed Central

    Mahmood, Deyar Jallal Hadi; Linderoth, Ewa H; Wennerberg, Ann; Vult Von Steyern, Per

    2016-01-01

    Aim To investigate and compare the fracture strength and fracture mode in eleven groups of currently, the most commonly used multilayer three-unit all-ceramic yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) fixed dental prostheses (FDPs) with respect to the choice of core material, veneering material area, manufacturing technique, design of connectors, and radii of curvature of FDP cores. Materials and methods A total of 110 three-unit Y-TZP FDP cores with one intermediate pontic were made. The FDP cores in groups 1–7 were made with a split-file design, veneered with manually built-up porcelain, computer-aided design-on veneers, and over-pressed veneers. Groups 8–11 consisted of FDPs with a state-of-the-art design, veneered with manually built-up porcelain. All the FDP cores were subjected to simulated aging and finally loaded to fracture. Results There was a significant difference (P<0.05) between the core designs, but not between the different types of Y-TZP materials. The split-file designs with VITABLOCS® (1,806±165 N) and e.max® ZirPress (1,854±115 N) and the state-of-the-art design with VITA VM® 9 (1,849±150 N) demonstrated the highest mean fracture values. Conclusion The shape of a split-file designed all-ceramic reconstruction calls for a different dimension protocol, compared to traditionally shaped ones, as the split-file design leads to sharp approximal indentations acting as fractural impressions, thus decreasing the overall strength. The design of a framework is a crucial factor for the load bearing capacity of an all-ceramic FDP. The state-of-the-art design is preferable since the split-file designed cores call for a cross-sectional connector area at least 42% larger, to have the same load bearing capacity as the state-of-the-art designed cores. All veneering materials and techniques tested in the study, split-file, over-press, built-up porcelains, and glass–ceramics are, with a great safety margin, sufficient for clinical use

  10. Residual Strain and Fracture Response of Al2O3 Coatings Deposited via APS and HVOF Techniques

    NASA Astrophysics Data System (ADS)

    Ahmed, R.; Faisal, N. H.; Paradowska, A. M.; Fitzpatrick, M. E.

    2012-01-01

    The aim of this investigation was to nondestructively evaluate the residual stress profile in two commercially available alumina/substrate coating systems and relate residual stress changes with the fracture response. Neutron diffraction, due to its high penetration depth, was used to measure residual strain in conventional air plasma-sprayed (APS) and finer powder high velocity oxy-fuel (HVOF (θ-gun))-sprayed Al2O3 coating/substrate systems. The purpose of this comparison was to ascertain if finer powder Al2O3 coatings deposited via θ-gun can provide improved residual stress and fracture response in comparison to conventional APS coatings. To obtain a through thickness residual strain profile with high resolution, a partially submerged beam was used for measurements near the coating surface, and a beam submerged in the coating and substrate materials near the coating-substrate interface. By using the fast vertical scanning method, with careful leveling of the specimen using theodolites, the coating surface and the coating/substrate interface were located with an accuracy of about 50 μm. The results show that the through thickness residual strain in the APS coating was mainly tensile, whereas the HVOF coating had both compressive and tensile residual strains. Further analysis interlinking Vickers indentation fracture behavior using acoustic emission (AE) was conducted. The microstructural differences along with the nature and magnitude of the residual strain fields had a direct effect on the fracture response of the two coatings during the indentation process.