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Tsuda M, Yunaga H, Murakami A, Yata S. Adaptive statistical iterative reconstruction for computed tomography of the spine. Radiography (Lond) 2021; 27:768-772. [PMID: 33384207 DOI: 10.1016/j.radi.2020.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/21/2020] [Accepted: 12/10/2020] [Indexed: 10/22/2022]
Abstract
INTRODUCTION The utility of evaluating a sagittal view of CT of the spine is well-known. In many clinical cases, the sagittal view includes noise generated from surrounding objects and may degrade the image quality. Iterative reconstruction (IR) techniques are useful for noise reduction; however, they can reduce spatial resolution. The aim of this study was to evaluate the effectiveness of the adaptive statistical iterative reconstruction (ASiR) for generating sagittal CT images of the spine when compared to filtered back projection (FBP). METHODS The image quality of clinical images from 25 patients were subjectively assessed. Three radiologists rated spatial resolution, image noise, and overall image quality using a five-point scale. For objective assessment, z-direction modulation transfer function (z-MTF) was measured using a custom-made phantom. Additionally, z-axis noise power spectrum (z-NPS) was measured using a water phantom. An improved adaptive statistical iterative reconstruction algorithm called ASiR-V was used in this study. Blending levels were 50%, and 100% (ASiR-V50, ASiR-V100, respectively). RESULTS For subjective assessments, images using ASiR-V100 were determined to have the best overall image quality, despite having received the worst score in the assessment of spatial resolution. For objective assessments, the image using ASiR-V50 and ASiR-V100 curves were slightly degraded in terms of low contrast z-MTF when compared to FBP. CONCLUSION ASiR-V was effective to improve the image quality when compared with FBP when reviewing sagittal reformats of the spine. IMPLICATIONS FOR PRACTICE This study suggests that high resolution is not the only thing that is key when reviewing sagittal CT spinal reformats. Such images should be provided as part of routine CT spine protocols, where available.
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Affiliation(s)
- M Tsuda
- Department of Radiological Technology, Tottori University Hospital, 36-1, Nishi-cho, Yonago-shi, Tottori-ken, 683-8504, Japan.
| | - H Yunaga
- Department of Radiology Tottori University Hospital, 36-1, Nishi-cho, Yonago-shi, Tottori-ken, 683-8504, Japan.
| | - A Murakami
- Department of Radiology Tottori University Hospital, 36-1, Nishi-cho, Yonago-shi, Tottori-ken, 683-8504, Japan.
| | - S Yata
- Department of Radiology Tottori University Hospital, 36-1, Nishi-cho, Yonago-shi, Tottori-ken, 683-8504, Japan.
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Kubosch D, Konstantinidis L, Helwig P, Hirschmüller A, Strohm PC, Südkamp NP. Relationship between autologous bone graft osteointegration and correction loss after antero-posterior spondylodesis of traumatic vertebral body fracture. Orthop Traumatol Surg Res 2015; 101:221-5. [PMID: 25736198 DOI: 10.1016/j.otsr.2014.12.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Accepted: 12/15/2014] [Indexed: 02/02/2023]
Abstract
BACKGROUND A common method to restore the sagittal alignment and stabilize the spinal column is a dorso-ventral spondylodesis. It is assumed that correction loss after posttraumatic spondylodesis results from inadequate incorporation of the autologous iliac crest graft. MATERIALS AND METHODS Retrospective documentation of patients with unstable vertebral body fractures of the thoracic or lumbar spine with concomitant rupture of at least one adjacent intervertebral disk who received surgical treatment at our institution from 2000 to 2006. Followed by analysis of the computer tomography documentation of a total of 142 patients with unstable vertebral body fracture stabilized by posterior internal fixator and anterior iliac crest spondylodesis. RESULTS The following mean angle changes were derived from the second series of CT scans performed on average 283 days after anterior spondylodesis: vertebral wedge angle (VWA): 2.1°; segmental kyphotic angle: 4.9°; adjusted-SKA: 4.8°; sagittal index (SI): -0.04; segmental-scoliotic-angle (SSA): 0°; adjusted-SSA: 0°. Changes in VWA, both SKAs and SI postoperatively and prior to ME, were statistically significant (P<0.05). The McAfee fusion assessment of the graft showed: full fusion: cranial 64%, caudal 47%; partial fusion: cranial 20.5%, caudal 29%; lysis: cranial 8.5%, caudal 17%; graft resorption: 7%. No correlation was found between the above-mentioned angle changes and fusions grade. DISCUSSION The importance of radiological evidence of fusion deficiency is questionable, because the extent of fusion only has a minimal effect on correction loss. LEVEL OF EVIDENCE Level IV.
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Affiliation(s)
- D Kubosch
- Klinikum der Albert-Ludwigs-Universität Freiburg, Department Orthopädie und Traumatologie, 79106 Freiburg im Breisgau, Germany.
| | - L Konstantinidis
- Klinikum der Albert-Ludwigs-Universität Freiburg, Department Orthopädie und Traumatologie, 79106 Freiburg im Breisgau, Germany
| | - P Helwig
- Klinikum der Albert-Ludwigs-Universität Freiburg, Department Orthopädie und Traumatologie, 79106 Freiburg im Breisgau, Germany
| | - A Hirschmüller
- Klinikum der Albert-Ludwigs-Universität Freiburg, Department Orthopädie und Traumatologie, 79106 Freiburg im Breisgau, Germany
| | - P C Strohm
- Klinikum der Albert-Ludwigs-Universität Freiburg, Department Orthopädie und Traumatologie, 79106 Freiburg im Breisgau, Germany
| | - N P Südkamp
- Klinikum der Albert-Ludwigs-Universität Freiburg, Department Orthopädie und Traumatologie, 79106 Freiburg im Breisgau, Germany
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Braunstein V, Ockert B, Windolf M, Sprecher CM, Mutschler W, Imhoff A, Postl LKL, Biberthaler P, Kirchhoff C. Increasing pullout strength of suture anchors in osteoporotic bone using augmentation--a cadaver study. Clin Biomech (Bristol, Avon) 2015; 30:243-7. [PMID: 25686676 DOI: 10.1016/j.clinbiomech.2015.02.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Revised: 02/01/2015] [Accepted: 02/02/2015] [Indexed: 02/07/2023]
Abstract
BACKGROUND Rotator cuff tears are of increasing clinical impact in the physically active elderly patients. Recent research revealed, that a high percentage of these patients present with significant loss of bone mineral density at the insertion site of the rotator cuff, thereby compromising suture anchorage for operative repair. We therefore hypothesized that augmentation of suture anchors improves biomechanical properties in low bone quality. METHODS 28 osteoporotic humeral heads were included in this biomechanical study. Bone quality at the anchor insertion sites (group 1: posterior-medial; group 2: anterior-lateral) within the greater tuberosity was analyzed using HR-pQCT (voxel size: 82μm). Anchor positions of identical quality were then randomized to either conventional screw anchorage or polymethylmethacrylat augmented screw anchorage. All anchors were cyclically ramp-loaded until pullout. FINDINGS Pullout strength accounted for 226N in group I for conventional anchorage and for 332N in augmented technique. In group 2 (anterior-lateral) the pullout strength was 209N (conventional) and 304N (augmented). Pull-out strength of augmented screw anchors was significantly higher in both groups (p<0.05). INTERPRETATION Compared to conventional insertion techniques, the cement augmentation technique increases the pullout strength of suture anchors in low bone quality significantly. Cement augmentation could therefore be a helpful tool for improved suture anchor stability, especially in locations of low bone quality.
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Affiliation(s)
- Volker Braunstein
- OrthoPlus-Muenchen, Germany; Department of Orthopedic Surgery and Traumatology, Ludwig-Maximilians-Universitaet, Muenchen, Germany
| | - Ben Ockert
- Department of Orthopedic Surgery and Traumatology, Ludwig-Maximilians-Universitaet, Muenchen, Germany
| | - Markus Windolf
- AO Research Institute, AO Foundation, Davos, Switzerland
| | | | - Wolf Mutschler
- Department of Orthopedic Surgery and Traumatology, Ludwig-Maximilians-Universitaet, Muenchen, Germany
| | - Andreas Imhoff
- Department of Sports Orthopedics, Technische Universitaet, Muenchen, Germany
| | | | - Peter Biberthaler
- Department of Trauma Surgery, Technische Universitaet, Muenchen, Germany
| | - Chlodwig Kirchhoff
- Department of Trauma Surgery, Technische Universitaet, Muenchen, Germany.
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Friedmann A, Friedmann A, Grize L, Obrecht M, Dard M. Convergent methods assessing bone growth in an experimental model at dental implants in the minipig. Ann Anat 2014; 196:100-7. [PMID: 24656913 DOI: 10.1016/j.aanat.2014.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 01/13/2014] [Accepted: 02/04/2014] [Indexed: 10/25/2022]
Abstract
Implant dentistry demonstrated its reliability in treating successfully an increased amount of patients with dental implants exhibiting hydrophilic (modSLA) or non-hydrophilic (SLA) surfaces. Objectives of this minipig study consisted in assessing bone regeneration at both types of dental implants in a new experimental model (lateral bone defects) by implementing a convergent analysis approach combining histology and contact radiography. In six adult female minipigs standardized acute alveolar defects were created, then receiving two implants in the mandibles bilaterally (modSLA and SLA, one of each combined with Guided Bone Regeneration). Animals were sacrificed after 28 days of healing. Mid-crestal specimen were analyzed assessing missing BIC to implant shoulder (fBIC); vertical bone growth upon implant surface, bone:tissue ratio and grafting material area occupied by material remnants for GBR sites. Values obtained from both analyses were compared and statistical correlations scrutinized. Although dimensions of mean differences and adjusted means given by radiographic method were lower than histological ones, comparison of different implants yielded similar results. Statistical analyses of correlation and concordance coefficients used to evaluate radiological method of measurement showed high level of concordance (concordance coefficient=0.912 and correlation coefficient=0.939) for fBIC. Similar results were observed for vertical new bone and for remnants of graft. Discrepancies for new bone and for mineralized tissue resulted in concordance coefficient of 0.182 and 0.054. The results indicate that contact X-rays can be used for morphometric assessments regarding defect fill; however, histological staining remains beneficial if greater resolution for distinguishing qualitative differences in the tissues is required.
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Affiliation(s)
- Anton Friedmann
- Department of Periodontology, School of Dentistry, Faculty of Health, University of Witten, Alfred-Herrhausen-Str. 44, 58455 Witten, Germany.
| | - Asisa Friedmann
- Department of Periodontology, School of Dentistry, Faculty of Health, University of Witten, Alfred-Herrhausen-Str. 44, 58455 Witten, Germany
| | - Leticia Grize
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | | | - Michel Dard
- Institute Staumann AG, Basel, Switzerland; New York University, College of Dentistry, NY, USA
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Kirchhoff C, Braunstein V, Milz S, Sprecher CM, Kirchhoff S, Graw M, Imhoff AB, Hinterwimmer S. Age and gender as determinants of the bone quality of the greater tuberosity: a HR-pQCT cadaver study. BMC Musculoskelet Disord 2012; 13:221. [PMID: 23148627 PMCID: PMC3517743 DOI: 10.1186/1471-2474-13-221] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 07/31/2012] [Indexed: 12/02/2022] Open
Abstract
Background Age-dependent trabecular changes of the humeral head might weaken the fixation of suture anchors used for rotator cuff (RC) repair. This might lead to suture anchor loosening and thus compromise the integrity of the repair. The aim of this study was to analyze whether the trabecular microstructure within the RC footprint is influenced by age, gender or handedness. Methods Axial HR-pQCT scans (Scanco Medical) of 64 freshly frozen cadaveric human humeral head specimens (age 72.3 ± 17.4 years) were analyzed to determine the bone volume-to-total volume ratio (BV/TV), trabecular thickness (Trab Th), trabecular number (Trab N) and connectivity density (Conn Dens). Within the RC footprint, 2 volumes of interest (VOI), posteromedial (PM) and anterolateral (AL) and one control VOI in the subarticular bone (SC) were set. Results The highest BV/TV was found in SC: 0.22 ± 0.06% vs. PM: 0.04 ± 0.05% vs. AL: 0.02 ± 0.04%; p < 0.05. Trab Th accounted for 0.26 ± 0.05 μm in SC, 0.23 ± 0.09 μm in AL and 0.21 ± 0.05 μm in PM. In parallel, Trab N and Conn Dens were found to be the highest in SC. Gender analysis yielded higher values for BV/TV, Trab Th, Trab N and Conn Dens for PM in males compared to females (p < 0.05). There were no significant findings when comparing both sides. We furthermore found a strong inverse correlation between age and BV/TV, which was more pronounced in the female specimens (r = −0.72, p < 0.00001). Conclusions The presented microarchitectural data allow for future subtle biomechanical testing comprising knowledge on age- and sex-related changes of the tuberosities of the humeral head. Furthermore, the insights on the trabecular structure of the humeral head of the elderly may lead to the development of new fixation materials in bone with inferior bone quality.
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Affiliation(s)
- Chlodwig Kirchhoff
- Department of Trauma Surgery, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaningerstrasse 22, D-81675, Munich, Germany.
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Risk of graft fracture after dorso-ventral thoraco-lumbar spondylodesis: is there a correlation with graft size? EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2011; 20:1644-9. [PMID: 21748494 DOI: 10.1007/s00586-011-1895-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 05/07/2011] [Accepted: 06/28/2011] [Indexed: 10/18/2022]
Abstract
STUDY DESIGN Retrospective clinical study in patients with dorso-ventral thoraco-lumbar spondylodesis. OBJECTIVE To investigate whether the ratio between graft cross sectional area and the surface area of the adjacent endplates has any effect on the midterm stability of the spondylodesis. Dorso-ventral spondylodesis in the region of the thoraco-lumbar spine is one of the most frequent operations in orthopaedic surgery. Anterior stabilization with autologous iliac crest graft currently is a standard approach in many hospitals. Although numerous recommendations are given how to perform this technique, no clinical advice is available with regard to minimum graft size. METHODS Sixty-four-slice CT-scans were obtained from 82 patients 4-12 months after posterior spondylodesis with anterior implantation of iliac crest graft and stabilization with an internal fixator. The scans were analyzed using image analysis software. First, the cross sectional area of the graft was calculated and then the surface area of the adjacent endplates. The ratio between graft cross sectional area and endplate surface area was then calculated from these two values. The grafts were then evaluated in sagittal reconstruction for signs of fracture. RESULTS The probability for graft fracture in autologous tricortical grafts was >0.1% (p < 0.001) if the graft cross sectional area exceeded 23.9% of the surface area of the adjacent endplates. Patients with lower ratio values had a higher fracture risk and below a value of 10% all grafts fractured. CONCLUSION The relationship between graft cross sectional area and adjacent endplate area has an important effect on graft midterm stability in ventral spondylodesis of the thoraco-lumbar spine. In our opinion, the risk of graft fractures in dorso-ventral spondylodesis can be reduced by implantation of an appropriately sized graft without any additional procedures or instrumentation.
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Kubosch D, Milz S, Sprecher CM, Südkamp NP, Müller CA, Strohm PC. Effect of graft size on graft fracture rate after anterior lumbar spinal fusion in a sheep model. Injury 2010; 41:768-71. [PMID: 19740465 DOI: 10.1016/j.injury.2009.08.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 07/28/2009] [Accepted: 08/17/2009] [Indexed: 02/02/2023]
Abstract
STUDY DESIGN Sheep anterior spinal fusion model with autogenous and xenogenous bone grafts. OBJECTIVE To investigate whether the relationship between cross-sectional area of the bone graft and area of the adjacent vertebral endplates has an effect on graft fracture rate. SUMMARY OF BACKGROUND DATA Anterior spondylodesis with autogenous iliac crest transplant is a frequently performed operation to stabilize spinal motion segments but to date no precise recommendations with respect to minimum graft size are available in the literature. METHODS Anterior spondylodesis using autogenous and xenogenous grafts of constant size in combination with an angular stable plate (Macs TL). Autogenous iliac crest graft was inserted in eight sheep and xenogenic, commercially available bovine graft (Tutobone) in the additional eight animals. The surface areas of the endplates of the fused intervertebral space were calculated using CT scans and contact radiographs of the specimens obtained after 24 weeks. The graft itself was evaluated for fractures and osteolysis. RESULTS A fracture occurred in tricortical, autogenous grafts if the graft cross-sectional area was less than 21% of the area of the adjacent endplates. All xenogenic grafts fractured and therefore a comparable value could not be determined. CONCLUSION The results clearly indicate that the relation between graft cross-sectional area and endplate area defines the survival or fracture of the graft in anterior spinal fusion. Although it is difficult to directly apply the results to the clinical situation it is suggested to choose a sufficiently large graft, in order to reduce the risk of autogenous graft fracture in anterior spondylodesis.
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Affiliation(s)
- David Kubosch
- Department of Orthopaedic and Trauma Surgery, University of Freiburg Medical Center, Hugstetterstr. 55, D-79106 Freiburg im Breisgau, Germany
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