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  • 1
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    Online Resource
    Influence of cage design on interbody fusion in a sheep cervical spine model
    Journal of Neurosurgery Publishing Group (JNSPG) ; 2002
    In:  Journal of Neurosurgery: Spine Vol. 96, No. 3 ( 2002-04), p. 321-332
    Details
    In: Journal of Neurosurgery: Spine, Journal of Neurosurgery Publishing Group (JNSPG), Vol. 96, No. 3 ( 2002-04), p. 321-332
    Abstract: Object. The purpose of this study was to compare the characteristics of interbody fusion achieved using an autologous tricortical iliac crest bone graft with those of a cylinder- and a box-design cage in a sheep cervical spine model. This study was designed to determine whether there are differences between three interbody fusion procedures in: 1) ability to preserve postoperative distraction; 2) biomechanical stability; and 3) histological characteristics of intervertebral bone matrix formation. Methods. Twenty-four sheep underwent C3–4 discectomy and fusion in which the following were used: Group 1, autologous tricortical iliac crest bone graft (eight sheep); Group 2, titanium cylinder-design cage filled with autologous iliac crest bone graft (eight sheep); and Group 3, titanium box-design cage filled with autologous iliac crest graft (eight sheep). Radiography was performed pre- and postoperatively and after 1, 2, 4, 8, and 12 weeks. At the same time points, disc space height, intervertebral angle, and lordosis angle were measured. After 12 weeks, the sheep were killed, and fusion sites were evaluated by obtaining functional radiographs in flexion and extension. Quantitative computerized tomography scans were acquired to assess bone mineral density, bone mineral content, and bone callus volume. Biomechanical testing was performed in flexion, extension, axial rotation, and lateral bending. Stiffness, range of motion, neutral zone, and elastic zone were determined. Histomorphological and histomorphometric analyses were performed, and polychrome sequential labeling was used to determine the time frame of new bone formation. Over a 12-week period significantly higher values for disc space height and intervertebral angle were shown in cage-treated sheep than in those that received bone graft. Functional radiographic assessment revealed significantly lower residual flexion—extension movement in sheep with the cylinder cage-fixed spines than in those that received bone graft group. The cylinder—design cages showed significantly higher values for bone mineral content, bone callus content, and stiffness in axial rotation and lateral bending than the other cages or grafts. Histomorphometric evaluation and polychrome sequential labeling showed a more progressed bone matrix formation in the cylindrical cage group than in both other groups. Conclusions. Compared with the tricortical bone graft, both cages showed significantly better distractive properties. The cylindrical cage demonstrated a significantly higher biomechanical stiffness and an accelerated interbody fusion compared with the box-design cage and the tricortical bone graft. The differences in bone matrix formation within both cages were the result of the significantly lower stress shielding on the bone graft by the cylinder-design cage.
    Type of Medium: Online Resource
    ISSN: 1547-5654
    URL: Article
    DOI: 10.3171/spi.2002.96.3.0321
    RVK:
    XA 55270.1
    Language: Unknown
    Publisher: Journal of Neurosurgery Publishing Group (JNSPG)
    Publication Date: 2002
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  • 2
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    Online Resource
    Role of iodine oxoacids in atmospheric aerosol nucleation
    American Association for the Advancement of Science (AAAS) ; 2021
    In:  Science Vol. 371, No. 6529 ( 2021-02-05), p. 589-595
    Details
    In: Science, American Association for the Advancement of Science (AAAS), Vol. 371, No. 6529 ( 2021-02-05), p. 589-595
    Abstract: Iodic acid (HIO 3 ) is known to form aerosol particles in coastal marine regions, but predicted nucleation and growth rates are lacking. Using the CERN CLOUD (Cosmics Leaving Outdoor Droplets) chamber, we find that the nucleation rates of HIO 3 particles are rapid, even exceeding sulfuric acid–ammonia rates under similar conditions. We also find that ion-induced nucleation involves IO 3 − and the sequential addition of HIO 3 and that it proceeds at the kinetic limit below +10°C. In contrast, neutral nucleation involves the repeated sequential addition of iodous acid (HIO 2 ) followed by HIO 3 , showing that HIO 2 plays a key stabilizing role. Freshly formed particles are composed almost entirely of HIO 3 , which drives rapid particle growth at the kinetic limit. Our measurements indicate that iodine oxoacid particle formation can compete with sulfuric acid in pristine regions of the atmosphere.
    Type of Medium: Online Resource
    ISSN: 0036-8075 , 1095-9203
    URL: Article
    DOI: 10.1126/science.abe0298
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: American Association for the Advancement of Science (AAAS)
    Publication Date: 2021
    detail.hit.zdb_id: 128410-1
    detail.hit.zdb_id: 2066996-3
    detail.hit.zdb_id: 2060783-0
    SSG: 11
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  • 3
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    Online Resource
    OF-Pelvis classification of osteoporotic sacral and pelvic ring fractures
    Springer Science and Business Media LLC ; 2021
    In:  BMC Musculoskeletal Disorders Vol. 22, No. 1 ( 2021-12)
    Details
    In: BMC Musculoskeletal Disorders, Springer Science and Business Media LLC, Vol. 22, No. 1 ( 2021-12)
    Abstract: Osteoporotic fractures of the pelvis (OFP) are an increasing issue in orthopedics. Current classification systems (CS) are mostly CT-based and complex and offer only moderate to substantial inter-rater reliability (interRR) and intra-rater reliability (intraRR). MRI is thus gaining importance as a complement. This study aimed to develop a simple and reliable CT- and MRI-based CS for OFP. Methods A structured iterative procedure was conducted to reach a consensus among German-speaking spinal and pelvic trauma experts over 5 years. As a result, the proposed OF-Pelvis CS was developed. To assess its reliability, 28 experienced trauma and orthopedic surgeons categorized 25 anonymized cases using X-ray, CT, and MRI scans twice via online surveys. A period of 4 weeks separated the completion of the first from the second survey, and the cases were presented in an altered order. While 13 of the raters were also involved in developing the CS (developing raters (DR)), 15 user raters (UR) were not deeply involved in the development process. To assess the interRR of the OF-Pelvis categories, Fleiss’ kappa (κ F ) was calculated for each survey. The intraRR for both surveys was calculated for each rater using Kendall’s tau (τ K ). The presence of a modifier was calculated with κ F for interRR and Cohen’s kappa (κ C ) for intraRR. Results The OF-Pelvis consists of five subgroups and three modifiers. Instability increases from subgroups 1 (OF1) to 5 (OF5) and by a given modifier. The three modifiers can be assigned alone or in combination. In both surveys, the interRR for subgroups was substantial: κ F  = 0.764 (Survey 1) and κ F  = 0.790 (Survey 2). The interRR of the DR and UR was nearly on par (κ F Survey 1/Survey 2: DR 0.776/0.813; UR 0.748/0.766). The agreement for each of the five subgroups was also strong (κ F min.–max. Survey 1/Survey 2: 0.708–0.827/0.747–0.852). The existence of at least one modifier was rated with substantial agreement (κ F Survey 1/Survey 2: 0.646/0.629). The intraRR for subgroups showed almost perfect agreement (τ K  = 0.894, DR: τ K  = 0.901, UR: τ K  = 0.889). The modifier had an intraRR of κ C  = 0.684 (DR: κ C  = 0.723, UR: κ C  = 0.651), which is also considered substantial. Conclusion The OF-Pelvis is a reliable tool to categorize OFP with substantial interRR and almost perfect intraRR. The similar reliabilities between experienced DRs and URs demonstrate that the training status of the user is not important. However, it may be a reliable basis for an indication of the treatment score.
    Type of Medium: Online Resource
    ISSN: 1471-2474
    URL: Article
    DOI: 10.1186/s12891-021-04882-6
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2021
    detail.hit.zdb_id: 2041355-5
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  • 4
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    Guideline-conform diagnostics for injuries of the subaxial cervical spine
    Springer Science and Business Media LLC ; 2020
    In:  Der Unfallchirurg Vol. 123, No. 8 ( 2020-08), p. 641-652
    Details
    In: Der Unfallchirurg, Springer Science and Business Media LLC, Vol. 123, No. 8 ( 2020-08), p. 641-652
    Type of Medium: Online Resource
    ISSN: 0177-5537 , 1433-044X
    URL: Article
    DOI: 10.1007/s00113-020-00839-x
    Language: German
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2020
    detail.hit.zdb_id: 3120926-9
    detail.hit.zdb_id: 1461952-0
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  • 5
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    Treatment of Fractures of the Thoracolumbar Spine: Recommendations of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU)
    SAGE Publications ; 2018
    In:  Global Spine Journal Vol. 8, No. 2_suppl ( 2018-09), p. 34S-45S
    Details
    In: Global Spine Journal, SAGE Publications, Vol. 8, No. 2_suppl ( 2018-09), p. 34S-45S
    Abstract: Abstract consensus paper with systematic literature review. Objective: The aim of this study was to establish recommendations for treatment of thoracolumbar spine fractures based on systematic review of current literature and consensus of several spine surgery experts. Methods: The project was initiated in September 2008 and published in Germany in 2011. It was redone in 2017 based on systematic literature review, including new AOSpine classification. Members of the expert group were recruited from all over Germany working in hospitals of all levels of care. In total, the consensus process included 9 meetings and 20 hours of video conferences. Results: As regards existing studies with highest level of evidence, a clear recommendation regarding treatment (operative vs conservative) or regarding type of surgery (posterior vs anterior vs combined anterior-posterior) cannot be given. Treatment has to be indicated individually based on clinical presentation, general condition of the patient, and radiological parameters. The following specific parameters have to be regarded and are proposed as morphological modifiers in addition to AOSpine classification: sagittal and coronal alignment of spine, degree of vertebral body destruction, stenosis of spinal canal, and intervertebral disc lesion. Meanwhile, the recommendations are used as standard algorithm in many German spine clinics and trauma centers. Conclusion: Clinical presentation and general condition of the patient are basic requirements for decision making. Additionally, treatment recommendations offer the physician a standardized, reproducible, and in Germany commonly accepted algorithm based on AOSpine classification and 4 morphological modifiers.
    Type of Medium: Online Resource
    ISSN: 2192-5682 , 2192-5690
    URL: Article
    DOI: 10.1177/2192568218771668
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2018
    detail.hit.zdb_id: 2648287-3
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  • 6
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    Traumatic Spondylolisthesis of the Axis Vertebra in Adults
    SAGE Publications ; 2015
    In:  Global Spine Journal Vol. 5, No. 4 ( 2015-08), p. 346-357
    Details
    In: Global Spine Journal, SAGE Publications, Vol. 5, No. 4 ( 2015-08), p. 346-357
    Abstract: Narrative review. Objective To elucidate the current concepts in diagnosis and treatment of traumatic spondylolisthesis of the axis. Methods Literature review using PubMed, Google Scholar, and Cochrane databases. Results The traumatic spondylolisthesis of the axis accounts to 5% of all cervical spine injuries and is defined by a bilateral separation of the C2 vertebral body from the neural arch. The precise location of the fracture line may vary widely. For understanding the pathobiomechanics, the involvement of the C2–C3 disk is essential. Although its synonym “hangman's fracture” suggests an extension moment as primary injury mechanism, flexion moments are also proven to cause such fracture morphology. The axial force vector (distraction versus compression) is thought to have a significant effect on the neurologic involvement. The most widely accepted classifications, according to Effendi and modified by Levine, regard the displacement of the C2 vertebral body and possible locking of the facet joints. For decisions on conservative versus surgical therapy, a definitive statement about the stability is essential. The stability is determined by involvement of the C2–C3 disk and longitudinal ligaments, which frequently cannot be assessed by X-ray or computed tomography alone. The assessment of this soft tissue injury therefore requires additional imaging either by magnetic resonance imaging to display the disk and longitudinal ligaments or dynamic fluoroscopy to assess functional behavior of the C2–C3 motion segment. If stability is proven, an immobilization of the cervical spine in a semirigid cervical collar is sufficient. Unstable lesions require surgical stabilization. The standard procedure is an anterior C2–C3 diskectomy and fusion, because of the lower morbidity of the anterior approach and the motion preservation between C1 and C2. In rare cases (irreducible locked facet joints, the necessity of decompression of the vertebral artery, contraindication for anterior approach), a posterior approach is sometimes necessary. Isolated direct screw osteosynthesis is of little value, because it only makes sense in cases with an intact C2–C3 disk, which is usually regarded as stable and therefore might be treated conservatively. Conclusions Overall, the clinical evidence regarding traumatic spondylolisthesis of the axis is very low and mainly based on small case series, expert opinion, laboratory findings, and theoretical considerations.
    Type of Medium: Online Resource
    ISSN: 2192-5682 , 2192-5690
    URL: Article
    DOI: 10.1055/s-0035-1550343
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2015
    detail.hit.zdb_id: 2648287-3
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  • 7
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    Online Resource
    Treatment of Atlas Fractures: Recommendations of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU)
    SAGE Publications ; 2018
    In:  Global Spine Journal Vol. 8, No. 2_suppl ( 2018-09), p. 5S-11S
    Details
    In: Global Spine Journal, SAGE Publications, Vol. 8, No. 2_suppl ( 2018-09), p. 5S-11S
    Abstract: Narrative review and expert recommendation. Objectives: To establish treatment recommendations for atlas fractures based on the knowledge of the experts of the Spine Section of the German Society for Orthopaedics and Trauma. Methods: Neither high-level evidence studies comparing conservative and operative management nor studies matching different operative treatment strategies exist. This recommendation summarizes the knowledge of the experts of the Spine Section of the German Society for Orthopaedics and Trauma with regard to the treatment of atlas fractures. Results: Most atlas fractures are the result of compression forces. A valuable morphological classification system has been described by Gehweiler. For an adequate diagnosis, a computed tomography is mandatory. To distinguish between stable and unstable type 3 injuries, it is necessary to evaluate the integrity of the transverse atlantal ligament (TAL) with magnetic resonance imaging and to classify the TAL lesions. The majority of atlas fractures are stable and will be successfully managed conservatively. Unstable atlas fractures (type 3b and sagittal split type 4 fractures) should be treated by surgical stabilization. Unstable atlas fractures (type 3b) with a midsubstance ligamentous disruption or severely dislocated ligamentous bony avulsions of the TAL can successfully be treated by a C1/2 fusion. Unstable atlas fractures (type 3b) with a moderately dislocated ligamentous bony avulsion of the TAL and sagittal split type 4 fractures may be treated by atlas osteosynthesis only. Conclusions: Whereas the majority of atlas fractures can be managed conservatively, in specific fracture patterns surgical treatment strategies have become the standard of care.
    Type of Medium: Online Resource
    ISSN: 2192-5682 , 2192-5690
    URL: Article
    DOI: 10.1177/2192568217726304
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2018
    detail.hit.zdb_id: 2648287-3
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  • 8
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    Online Resource
    Informed Consent for Lumbar Fusion Aided by Tablet-PC: A Prospective, Randomized, Controlled, and Blinded Comparison
    SAGE Publications ; 2016
    In:  Global Spine Journal Vol. 6, No. 1_suppl ( 2016-04), p. s-0036-1582746-s-0036-1582746
    Details
    In: Global Spine Journal, SAGE Publications, Vol. 6, No. 1_suppl ( 2016-04), p. s-0036-1582746-s-0036-1582746
    Type of Medium: Online Resource
    ISSN: 2192-5682 , 2192-5690
    URL: Article
    DOI: 10.1055/s-0036-1582746
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2016
    detail.hit.zdb_id: 2648287-3
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  • 9
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    Online Resource
    Radiographic and safety details of vertebral body stenting: results from a multicenter chart review
    Springer Science and Business Media LLC ; 2013
    In:  BMC Musculoskeletal Disorders Vol. 14, No. 1 ( 2013-12)
    Details
    In: BMC Musculoskeletal Disorders, Springer Science and Business Media LLC, Vol. 14, No. 1 ( 2013-12)
    Abstract: Up to one third of BKP treated cases shows no appreciable height restoration due to loss of both restored height and kyphotic realignment after balloon deflation. This shortcoming has called for an improved method that maintains the height and realignment reached by the fully inflated balloon until stabilization of the vertebral body by PMMA-based cementation. Restoration of the physiological vertebral body height for pain relief and for preventing further fractures of adjacent and distant vertebral bodies must be the main aim for such a method. A new vertebral body stenting system (VBS) stabilizes the vertebral body after balloon deflation until cementation. The radiographic and safety results of the first 100 cases where VBS was applied are presented. Methods During the planning phase of an ongoing international multicenter RCT, radiographic, procedural and followup details were retrospectively transcribed from charts and xrays for developing and testing the case report forms. Radiographs were centrally assessed at the institution of the first/senior author. Results 100 patients (62 with osteoporosis) with a total of 103 fractured vertebral bodies were treated with the VBS system. 49 were females with a mean age of 73.2 years; males were 66.7 years old. The mean preoperative anterior-middle-posterior heights were 20.3-17.6-28.0 mm, respectively. The mean local kyphotic angle was 13.1°. The mean preoperative Beck Index (anterior edge height/posterior edge height) was 0.73, the mean alternative Beck Index (middle height/posterior edge height) was 0.63. The mean postoperative heights were restored to 24.5-24.6-30.4 mm, respectively. The mean local kyphotic angle was reduced to 8.9°. The mean postoperative Beck Index was 0.81, the mean alternative one was 0.82. The overall extrusion rate was 29.1%, the symptomatic one was 1%. In the osteoporosis subgroup there were 23.8% extrusions. Within the three months followup interval there were 9% of adjacent and 4% of remote new fractures, all in the osteoporotic group. Conclusions VBS showed its strengths especially in realignment of crush and biconcave fractures. Given that fracture mobility is present, the realignment potential is sound and increases with the severity of preoperative vertebral body deformation.
    Type of Medium: Online Resource
    ISSN: 1471-2474
    URL: Article
    DOI: 10.1186/1471-2474-14-233
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2013
    detail.hit.zdb_id: 2041355-5
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  • 10
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    Online Resource
    Exploiting the Natural Diversity of RhlA Acyltransferases for the Synthesis of the Rhamnolipid Precursor 3-(3-Hydroxyalkanoyloxy)Alkanoic Acid
    American Society for Microbiology ; 2020
    In:  Applied and Environmental Microbiology Vol. 86, No. 6 ( 2020-03-02)
    Details
    In: Applied and Environmental Microbiology, American Society for Microbiology, Vol. 86, No. 6 ( 2020-03-02)
    Abstract: While rhamnolipids of the Pseudomonas aeruginosa type are commercially available, the natural diversity of rhamnolipids and their origin have barely been investigated. Here, we collected known and identified new rhlA genes encoding the acyltransferase responsible for the synthesis of the lipophilic rhamnolipid precursor 3-(3-hydroxyalkanoyloxy)alkanoic acid (HAA). Generally, all homologs were found in Betaproteobacteria and Gammaproteobacteria . A likely horizontal gene transfer event into Actinobacteria is the only identified exception. The phylogeny of the RhlA homologs from Pseudomonas and Burkholderia species is consistent with the organism phylogeny, and genes involved in rhamnolipid synthesis are located in operons. In contrast, RhlA homologs from the Enterobacterales do not follow the organisms’ phylogeny but form their own branch. Furthermore, in many Enterobacterales and Halomonas from the Oceanospirillales , an isolated rhlA homolog can be found in the genome. The RhlAs from Pseudomonas aeruginosa PA01, Pseudomonas fluorescens LMG 05825, Pantoea ananatis LMG 20103, Burkholderia plantarii PG1, Burkholderia ambifaria LMG 19182, Halomonas sp. strain R57-5, Dickeya dadantii Ech586, and Serratia plymuthica PRI-2C were expressed in Escherichia coli and tested for HAA production. Indeed, except for the Serratia RhlA, HAAs were produced with the engineered strains. A detailed analysis of the produced HAA congeners by high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) highlights the congener specificity of the RhlA proteins. The congener length varies from 4 to 18 carbon atoms, with the main congeners consisting of different combinations of saturated or monounsaturated C 10 , C 12 , and C 14 fatty acids. The results are discussed in the context of the phylogeny of this unusual enzymatic activity. IMPORTANCE The RhlA specificity explains the observed differences in 3-(3-hydroxyalkanoyloxy)alkanoic acid (HAA) congeners. Whole-cell catalysts can now be designed for the synthesis of different congener mixtures of HAAs and rhamnolipids, thereby contributing to the envisaged synthesis of designer HAAs.
    Type of Medium: Online Resource
    ISSN: 0099-2240 , 1098-5336
    URL: Article
    DOI: 10.1128/AEM.02317-19
    RVK:
    WA 15000
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2020
    detail.hit.zdb_id: 223011-2
    detail.hit.zdb_id: 1478346-0
    SSG: 12
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