Papers - CHOSA Etsuo
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Influence of bioresorbable, unsintered hydroxyapatite/poly-L-lactide composite films on spinal cord, nerve roots, and epidural space.
Matsumoto M, Chosa E, Nabeshima K, Shikinami Y, Tajima N
Journal of biomedical materials research 60 ( 1 ) 101 - 9 2002.4
Language：Japanese Publishing type：Research paper (scientific journal)
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Matsumoto M., Chosa E., Nabeshima K., Shikinami Y., Tajima N.
Journal of Biomedical Materials Research 60 ( 1 ) 101 - 109 2002.2
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Biomedical Materials Research
The effect of forged unsintered hydroxyapatite/poly-L-lactide (u-HA/PLLA) composite films on spinal cord and nerve roots and its degradation behavior and osteoconductivity in epidural space were compared with those of calcined HA (c-HA)/PLLA and unfilled PLLA films. Partial laminectomy was performed on 20 rabbits, and u-HA/PLLA and PLLA films were implanted in the intervertebral space. Total laminectomy was performed on 30 rabbits to implant u-HA/PLLA, c-HA/PLLA, and PLLA films in both epidural and subcutaneous spaces. For up to 50 weeks, there were no histological changes in the spinal cord or nerve root, and no inflammatory cell infiltration into the epidural space around the films. The rate of decrease in viscosity average molecular weight of both composite films was initially higher than that of PLLA but eventually became lower, although there was no difference in the degradation behavior of the three films in either the epidural or subcutaneous spaces after 50 weeks. Scanning electron microscopic and energy-dispersive X-ray analysis indicated calcium phosphate deposits on the surface of composite films with new bone formation from 4 weeks. The u-HA/PLLA composite film therefore has good biocompatibility, osteoconductivity, and fast primary degradation rate, which may prove compatible with application to spinal surgery. © 2002 John Wiley & Sons, Inc.
DOI： 10.1002/jbm.1283
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Effect of direct angiogenesis inhibition in rheumatoid arthritis using a soluble vascular endothelial growth factor receptor 1 chimeric protein.
Sekimoto T, Hamada K, Oike Y, Matsuoka T, Matsumoto M, Chosa E, Suda T, Tajima N, Yamamura K
The Journal of rheumatology 29 ( 2 ) 240 - 5 2002.2
Language：Japanese Publishing type：Research paper (scientific journal)
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Mechanical analysis of the lumbar vertebrae in a three-dimensional finite element method model in which intradiscal pressure in the nucleus pulposus was used to establish the model.
Goto K, Tajima N, Chosa E, Totoribe K, Kuroki H, Arizumi Y, Arai T
Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association 7 ( 2 ) 243 - 6 2002
Language：Japanese Publishing type：Research paper (scientific journal)
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Biochemical and morphological changes in herniated human intervertebral disc
AHSAN RASHEDUL, TAJIMA NAOYA, CHOSA ETSUO, SUGAMATA MASAO, SUMIDA MICHIHIRO, HAMADA MINORU
Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association 6 ( 6 ) 510 - 518 2001.12
Language：Japanese Publishing type：Research paper (scientific journal)
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Biochemical and morphological changes in herniated human intervertebral disc
Ahsan R., Tajima N., Chosa E., Sugamata M., Sumida M., Hamada M.
Journal of Orthopaedic Science 6 ( 6 ) 510 - 518 2001.1
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Orthopaedic Science
The molecular and morphologic features of herniated human intervertebral disc tissues are of particular importance to clarify the pathogenesis. The present study analyzed the biochemical and morphological features of herniated intervertebral disc tissues to determine the constituent factors responsible for intervertebral disc herniation. A total of 32 herniated disc specimens and 4 control disc samples were analyzed. Collagen subunit composition, collagenase activity, lipid peroxidation level, caspase-3 activity, metal levels, morphologic studies, and genetic analysis were performed on herniated disc tissues of chronic (group A) and acute (group B) group and compared with findings of control group. Nick translation analysis in situ revealed apoptotic-positive stained DNA fragments as black-brown spots in herniated disc tissues. The presence of type II collagen in control disc samples and its absence in herniated samples were confirmed immunohistochemically. The increased caspase-3 activity, the apoptotic-positive stained DNA fragments, and the electron microscopic findings suggest enhanced programmed cell death in herniated discs. The significant increase in lipid peroxidation levels and collagenase activity, and the low metal levels suggest the enhancement of cell death signals in herniated discs, caused by oxygen stress. Linkage analysis of herniated disc tissues in Japanese individuals may suggest ethnic variation. These findings may be helpful in understanding the pathogenesis of herniated disc disease.
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Kawagoe S., Tajima N., Chosa E.
Journal of Orthopaedic Science 5 ( 2 ) 124 - 133 2000.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Orthopaedic Science
Individual experience reveals that posterior foot placement enables one to stand up easily from a chair. However, the way in which foot placement affects this motion has not been investigated in detail. This study was performed to examine the effects of foot placement in the initial stage of the dynamics of standing up from a chair. Subjects wearing light-emitting diode markers and surface electrodes stood up from a chair over force plates, and ground reaction force, joint angle, and muscle activity were measured. The motions required to stand up from chairs 30, 40, or 50 cm in height were analyzed with anterior, vertical, and posterior foot placement. With anterior foot placement, the forward-acceleration components of the ground reaction force were recorded with simultaneous and long-sustained activity of the muscles in order to shift the center of gravity of the body forward even more after lift-off. Our findings indicate that the distance between the center of gravity and the point of application of ground reaction force at lift-off are critical factors in the standing-up motion, and that chairs should be of adequate height as well as having sufficient space under the seat to permit the backward movement of the lower legs.
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Kubo S., Tajima N., Chosa E., Goto K.
Studies in Health Technology and Informatics 59 285 - 288 1999.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Studies in Health Technology and Informatics
The purpose of this study is to evaluate the effects of thoracic microdiscectomy(anterior release) and arthrolysis of costotransverse joint(partial resection of transverse process) as additional technique in posterior procedure for scoliosis. Subjects consisted of 11 idiopathic scoliosis patients (1 male and 10 females) aged 12 to 17 years(average:15.3), operated posteriorly using CD technique. The subjects were divided into 3 groups ; group A: three patients operated without release, group B: four patients with arthrolysis of costotransverse joint, group C ; four patients with microdiscectomy of three discs around the apical vertebra and arthrolysis of costotransverse joint, the average preoperative Cobb angle were, respectively, 56, 52 and 55 degrees. Cobb angle and disc wedge angle were measured. The correction rates of Cobb angle in the group A,B and C were 77%, 65%, and 53%, respectively. Improvement in the disc wedge angle was obtained especially in-group A. Microdiscectomy appeared to be effective to de-stabilize the thoracic curve. This additional technique provide excellent correction in one stage posterior procedure. Concerning to the arthrolysis of the costotransverse joint,more detailed study and biomechanical examination are needed for accurate evaluation.
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Totoribe K., Tajima N., Chosa E.
Journal of Orthopaedic Science 4 ( 2 ) 115 - 126 1999.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Orthopaedic Science
Biomechanical analyses under compressive load, flexion, and extension torque were performed, using a nonlinear three-dimensional finite element method, to evaluate stability in posterolateral fusion. Effects of facet fusion and disc denucleation on posterolateral fusion were also examined. Using an initially prepared L4-5 motion segment model, we prepared a denucleation model, posterolateral fusion models classified by presence or absence of denucleation and facet fusion, and an interbody fusion model. In the denucleation model, rigidity was less than in the normal model, and maximum rigidity was analyzed for the interbody fusion model. The effect of denucleation on posterolateral fusion was also analyzed. Taking into account the instability of the anterior elements, including the intervertebral disc, appears to be clinically important. In the posterolateral fusion model under compressive load, the axis of rotation moved principally toward the fusion mass, and axial displacement and flexion rotation were induced. Sagittal rotation angles under flexion and extension torque were 1.5°-2.3°at a maximum moment of 15N-m, demonstrating elasticity of posterolateral fusion. When combined with facet fusion, posterolateral fusion yielded increase of load transfer across the lamina and decrease of rotation angle of about 10% under flexion-extension torque. Adjunctive clinical use of facet fusion should permit more solid posterolateral fusion.
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Segmental square spinal instrumentation for posterior lumbar spinal fixation
Tajima N., Tajima N., Chosa E., Kubo S., Kuroki H., Matsumoto M.
Journal of Spinal Disorders 12 ( 3 ) 240 - 244 1999.1
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Spinal Disorders
The purpose of this study is to evaluate the clinical results of operations using a new spinal instrumentation for posterior fixation, called segmental square spinal (3-S) instrumentation. The 3-S instrument consists of two pairs of hooks to clasp the interarticular portion of the lamina bilaterally, two horizontal bars to connect the hooks on the fight and left, and rods to connect the hooks side by side on the top and bottom. Twenty- seven patients who had degenerative lumbar disorders underwent operations with the 3-S instrument. Rigid fixation was obtained in all cases immediately after the operation. Bone union rates were 91% (21/23) with posterolateral fusion. The 3-S instrument seems to be suitable for spinal disorders in which anterior spinal fusion is not necessary, especially for degenerative spinal disorders.
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A cement spacer for two-stage revision of infected implants of the hip joint
Leunig M., Leunig M., Chosa E., Speck M., Ganz R.
International Orthopaedics 22 ( 4 ) 209 - 214 1998.10
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：International Orthopaedics
We report the technical details and clinical results of twelve patients who had deep infections of implants in the hip joint and were treated by two-stage revision, using a gentamicin-loaded, hand-moulded cement spacer inserted for the period between resection and reimplantation arthroplasty. During management with the spacer, usually for 4 months, patients were almost free of pain and mobile with good leg control, spending 2/3 of the treatment period at home. Six of twelve spacers failed locally due to dislocation [5] or cement fracture [1], and more than two further episodes of surgery were required in 3 patients. Problems with dislocation of the spacer were significantly higher when the head to neck offset was lacking (P < 0.05) or when anchorage in the femoral shaft was poor. Nevertheless, infection after reimplantation arthroplasty did not occur by the time of follow-up (2.2 years). Based on these data, we consider that the use of the cement spacer is a promising approach to the treatment of complicated infections of the hip joint.
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Posterolateral lumbar fusion - Biomechanical study and clinical results
Tajima N., Chosa E., Totoribe K., Kubo S., Kuroki H.
Journal of Musculoskeletal Research 2 ( 2 ) 101 - 107 1998.6
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Musculoskeletal Research
This paper discusses the biomechanics and long-term results of posterolateral (PL) lumbar fusion for degenerative lumbar spinal diseases. In the biomechanical study, the geometry of the finite element model is based on the L4-5 motion segment. The disc degeneration model was simulated by changing the interbody material properties. The behavior of the PL fusion model and the effects of the anterior elements on PL lumbar fusion were studied in compression, flexion, and extension. In the clinical study, 40 patients with a mean age of 39 years (19 to 63) were treated with PL fusion and the mean follow-up period was 14 years. Clinical evaluation was made by the Japanese Orthopaedic Association (J.O.A.) score. Fusion success was determined by X-ray radiographs. Stress distribution results indicate that there were high stresses in the upper part of the grafted bone for PL fusion. The axial displacement of the L4 vertebral body and the stress of the grafted bone for PL fusion increased in the disc degeneration model. In flexion, the extension load stress concentrated on the L4 side of PL fusion model between transverse processes. Clinically, the J.O.A. score improved by 24 points postoperatively. Radiographically, the success rate of the fusion was 93%. The long-term results were so good that this technique can be recommended. It is suggested that the instability including the degree of disc degeneration is one of the important factors in PL lumbar fusion. © World Scientific Publishing Company.
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Cement Spacer Technique in 2-stage Revision for Infected Hip Implants
CHOSA E., LEUNIG M, GANZ R
72 ( 2 ) 1998.2
Language：Japanese Publishing type：Research paper (scientific journal)
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Tajima N., Totoribe K., Chosa E.
Studies in Health Technology and Informatics 37 185 - 188 1997.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Studies in Health Technology and Informatics
Biomechanical characteristics of the interarticular portion of the lumbar vertebra were investigated using a three-dimensional finite element method. Stress distribution results indicate that there were high stresses in the pars interarticularis, especially the ventral cortical bone of it, and the anterior shear force had an increasing effect on the magnitude of the stress in the pars interarticularis. 3D-CT is helpful in understanding the complex anatomy such as the spine. The results of finite-element studies and 3D-CT were in good agreement with each other. It is suggested that the stress on the interarticular portion of lumbar vertebra is an important factor in the etiology of spondylolysis.
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Assessment of periacetabular osteotomy by anteroposterior and false profile views of the hip joint
CHOS Etsuo, GANZ R., KLAUE K.
Hip Joint 22 387 - 390 1996.9
Language：Japanese Publishing type：Research paper (scientific journal)
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Cement spacer technique in 2-stage revision for infected hip arthroplasty
CHOSA Etsuo, GANZ R.
Hip Joint 22 467 - 470 1996.9
Language：Japanese Publishing type：Research paper (scientific journal)