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Michael Mayer Juliane Zenner Robert Bogner Wolfgang Hitzl Markus Figl Arvind von Keudell Daniel Stephan Rainer Penzkofer Peter Augat Gundobert Korn Herbert Resch Heiko Koller 《European spine journal》2013,22(1):46-53
Study purpose
With increasing usage within challenging biomechanical constructs, failures of C2 posterior cervical pedicle screws (C2-pCPSs) will occur. The purpose of the study was therefore to investigate the biomechanical characteristics of two revision techniques after the failure of C2-pCPSs.Materials and methods
Twelve human C2 vertebrae were tested in vitro in a biomechanical study to compare two strategies for revision screws after failure of C2-pCPSs. C2 pedicles were instrumented using unicortical 3.5-mm CPS bilaterally (Synapse/Synthes, Switzerland). Insertion accuracy was verified by fluoroscopy. C2 vertebrae were potted and fixed in an electromechanical testing machine with the screw axis coaxial to the pullout direction. Pullout testing was conducted with load and displacement data taken continuously. The peak load to failure was measured in newtons (N) and is reported as the pullout resistance (POR). After pullout, two revision strategies were tested in each vertebra. In Group-1, revision was performed with 4.0-mm C2-pCPSs. In Group-2, revision was performed with C2-pedicle bone-plastic combined with the use of a 4-mm C2-pCPSs. For the statistical analysis, the POR between screws was compared using absolute values (N) and the POR of the revision techniques normalized to that of the primary procedures (%).Results
The POR of primary 3.5-mm CPSs was 1,140.5 ± 539.6 N for Group-1 and 1,007.7 ± 362.5 N for Group-2; the difference was not significant. In the revision setting, the POR in Group-1 was 705.8 ± 449.1 N, representing a reduction of 38.1 ± 32.9 % compared with that of primary screw fixation. For Group-2, the POR was 875.3 ± 367.9 N, representing a reduction of 13.1 ± 23.4 %. A statistical analysis showed a significantly higher POR for Group-2 compared with Group-1 (p = 0.02). Although the statistics showed a significantly reduced POR for both revision strategies compared with primary fixation (p < 0.001/p = 0.001), the loss of POR (in %) in Group-1 was significantly higher compared with the loss in Group-2 (p = 0.04).Conclusions
Using a larger-diameter screw combined with the application of a pedicle bone-plastic, the POR can be significantly increased compared with the use of only an increased screw diameter. 相似文献54.
Heiko Koller Oliver Meier Juliane Zenner Michael Mayer Wolfgang Hitzl 《European spine journal》2013,22(4):747-758
Introduction
To better understand cervical kinematics following cervical disc replacement (CDR), the in vivo behavior of a minimally constrained CDR was assessed.Methods
Radiographic analysis of 19 patients undergoing a 1-level CDR from C4–5 to C6–7 (DISCOVER, Depuy-Spine, USA) was performed. Neutral–lateral and flexion–extension radiographs obtained at preop, postop and late follow-up were analyzed for segmental angle and global angle (GA C2–7). Flexion–extension range of motion was analyzed using validated quantitative motion analysis software (QMA®, Medical Metrics, USA). The FSU motion parameters measured at the index and adjacent levels were angular range of motion (ROM), translation and center of rotation (COR). Translation and COR were normalized to the AP dimension of the inferior endplate of the caudal vertebra. All motion parameters, including COR, were compared with normative reference data.Results
The average patient age was 43.5 ± 7.3 years. The mean follow-up was 15.3 ± 7.2 months. C2–7 ROM was 35.9° ± 15.7° at preop and 45.4° ± 13.6° at follow-up (?p < .01). Based on the QMA at follow-up, angular ROM at the CDR level measured 9.8° ± 5.9° and translation was 10.1 ± 7.8 %. Individuals with higher ROM at the CDR level had increased translation at that level (p < .001, r = 0.97), increased translation and ROM at the supra-adjacent level (p < .001, r = .8; p = .005, r = .6). There was a strong interrelation between angular ROM and translation at the supra-adjacent level (p < .001, r = .9) and caudal-adjacent level (p < .001, r = .9). The location of the COR at the CDR- and supra-adjacent levels was significantly different for the COR-X (p < .001). Notably, the COR-Y at the CDR level was significantly correlated with the extent of CDR-level translation (p = .02, r = .6). Shell angle, which may be influenced by implant size and positioning had no impact on angular ROM but was correlated with COR-X (p = .05, r = ?.6) and COR-Y (p = .04, r = ?.5).Conclusion
The COR is an important parameter for assessing the ability of non-constrained CDRs to replicate the normal kinematics of a FSU. CDR size and location, both of which can impact shell angle, may influence the amount of translation by affecting the location of the COR. Future research is needed to show how much translation is beneficial concerning clinical outcomes and facet loading. 相似文献55.
Susanne Singer PhD Dorit Wollbrück MSc Andreas Dietz MD Juliane Schock MD Friedemann Pabst MD Hans‐Joachim Vogel MD Jens Oeken MD Annett Sandner MD Sven Koscielny MD Karl Hormes Kerstin Breitenstein MD Heike Richter Andreas Deckelmann Sarah Cook MSc Michael Fuchs MD Sylvia Meuret MD 《Head & neck》2013,35(11):1583-1590
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André de Carvalho SALES-PERES Juliane Avansini MARSICANO Rudan Paraíso GARCIA Moacir Rossi FORIM Maria Fatima das Gra?as Fernandes da SILVA Sílvia Helena de Carvalho SALES-PERES 《Journal of applied oral science : revista FOB》2013,21(6):597-600
Objective
To evaluate the efficacy of Neem (Azadirachta indica) experimental gel for the prevention of erosive wear on bovine dentin, in vitro.Material and Methods
One hundred dentin blocks were allocated into 5 experimental groups (20 samples each): C (control group, without gel); CG (control group, only base gel); F (fluoride gel, 1.23% NaF; pH 4.1, Dentsply; Brazil); N (Neem gel, 10% neem extract; pH 4.1, manipulation); NF (Neem+fluoride gel, 10% Neem extract and 1.23% NaF; pH 4.1, manipulation). The blocks were stored in artificial saliva for 24 hours. After this, they were submitted to six alternating re- and demineralization cycles. The blocks were analyzed for wear (profilometry). The results were submitted to statistical analysis by ANOVA and Tukey tests (P<0.05).Results
The mean wear (±SD, µm) was shown as follows in groups: C (13.09±0.99), CG (10.60±1.99), F (10.90±1.44), N (12.68±1.13) and NF (10.84±1.65). All gels showed some preventive action when compared with control group. However, significant differences were found only between Neem+fluoride gel and fluoride gel.Conclusion
A single application of a neem-containing fluoride gel reduced dentin erosion, thus it is a possible alternative in reducing dental wear. Further research should investigate the action mechanism and the synergism between them. 相似文献58.
Dorothea Buck MD Eva Albrecht DiplStat Muhammad Aslam PhD An Goris PhD Natalie Hauenstein Angela Jochim MD International Multiple Sclerosis Genetics Consortium Wellcome Trust Case Control Consortium Sabine Cepok PhD Verena Grummel Bénédicte Dubois MD PhD Achim Berthele MD Peter Lichtner PhD Christian Gieger PhD Juliane Winkelmann MD Bernhard Hemmer MD 《Annals of neurology》2013,73(1):86-94
59.
Biallelic AOPEP Loss-of-Function Variants Cause Progressive Dystonia with Prominent Limb Involvement
Michael Zech MD Kishore R. Kumar MBBS PhD FRACP Sophie Reining MD Janine Reunert PhD Michel Tchan MBBS PhD FRACP Lisa G. Riley PhD Alexander P. Drew PhD Robert J. Adam MA MBBS PhD FRACP FRCP Riccardo Berutti PhD Saskia Biskup MD Nicolas Derive PhD Somayeh Bakhtiari PhD Sheng Chih Jin PhD Michael C. Kruer MD Tanya Bardakjian MS Pedro Gonzalez-Alegre MD PhD Ignacio J. Keller Sarmiento MD Niccolo E. Mencacci MD PhD Steven J. Lubbe PhD Manju A. Kurian PhD Fabienne Clot PhD Aurélie Méneret MD PhD Jean-Madeleine de Sainte Agathe MD Victor S.C. Fung MBBS PhD FRACP Marie Vidailhet MD Matthias Baumann MD Thorsten Marquardt MD Juliane Winkelmann MD Sylvia Boesch MD 《Movement disorders》2022,37(1):137-147
60.
Boesl Fabian Allers Kristina Herm Juliane Scheider Thomas Franke Christiana 《Journal of neurovirology》2022,28(2):335-338
Journal of NeuroVirology - Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease of the CNS caused by the human polyomavirus 2 (JCV). PML predominantly occurs in... 相似文献