Updated on 2024/07/13

写真a

 
HIRANO Toru
 
Organization
University Medical and Dental Hospital Uonuma Institute of Community Medicine Specially Appointed Professor
Title
Specially Appointed Professor
External link

Degree

  • 医学博士 ( 1999.3   新潟大学 )

Research History (researchmap)

  • Niigata University   Graduate School of Medical and Dental Sciences Biological Functions and Medical Control Regenerative and Transplant Medicine   Associate Professor

    2014.12

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  • Niigata University   Graduate School of Medical and Dental Sciences Biological Functions and Medical Control   Lecturer

    2009.10

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  • Niigata University   Graduate School of Medical and Dental Sciences Biomedical Sciences   Lecturer

    2009.10

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  • Niigata University   University Medical and Dental Hospital Orthopedic Surgery   Lecturer

    2009.10 - 2014.11

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  • Niigata University   Graduate School of Medical and Dental Sciences Biological Functions and Medical Control   Assistant Professor

    2007.4 - 2009.9

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  • Niigata University   Graduate School of Medical and Dental Sciences   Research Assistant

    2001.6 - 2007.3

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Research History

  • Niigata University   University Medical and Dental Hospital UONUMA CHIIKI IRYO KYOIKU CENTER JUNBISHITU   Specially Appointed Professor

    2019.4

  • Niigata University   Graduate School of Medical and Dental Sciences Biological Functions and Medical Control Regenerative and Transplant Medicine   Associate Professor

    2014.12 - 2019.3

  • Niigata University   University Medical and Dental Hospital Orthopedic Surgery   Lecturer

    2009.10 - 2014.11

  • Niigata University   Graduate School of Medical and Dental Sciences Biomedical Sciences   Lecturer

    2009.10 - 2014.11

  • Niigata University   Graduate School of Medical and Dental Sciences Biological Functions and Medical Control   Lecturer

    2009.10 - 2014.11

  • Niigata University   Graduate School of Medical and Dental Sciences Biological Functions and Medical Control   Assistant Professor

    2007.4 - 2009.9

  • Niigata University   Graduate School of Medical and Dental Sciences   Research Assistant

    2001.6 - 2007.3

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Papers

  • Body mass index is associated with low back pain in childhood and adolescence: a birth cohort study with a 6-year follow-up in Niigata City, Japan Reviewed

    Atsuki Sano, Toru Hirano, Kei Watanabe, Naoto Endo, Takui Ito, Naohito Tanabe

    European Spine Journal   24 ( 3 )   474 - 481   2015.3

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Springer Verlag  

    Purpose: To investigate the successive change of low back pain (LBP) prevalence in childhood and adolescence and to examine the associations between LBP and extracurricular sports activities (ECSA) or body mass index (BMI) using a 6-year birth cohort study.
    Methods: LBP reports of a grade (4,597 pupils at the beginning) were tracked over 6 years (between the ages of 9 and 14 years old), and anonymous questionnaires were distributed to them yearly. After grading the severity of the LBP into three levels and noting the transitions of the point and the lifetime prevalence of LBP, associations between point prevalence of LBP and BMI or ECSA were evaluated.
    Results: The point prevalence of LBP had a tendency to become significantly higher as the pupils got older until they became 13 years old. The lifetime prevalence of LBP significantly increased as they got older yearly. As for the severity of LBP among students with a lifetime prevalence, the rate of more severe LBP (levels 2 and 3) increased as they got older. Significant positive associations were recognized between BMI and point prevalence of LBP in every years old (p &lt
     0.05) and between ECSA and point prevalence of LBP at 11 (p = 0.001) and 14 years old (p &lt
     0.001).
    Conclusions: The point and lifetime prevalence of LBP and the rate of more severe LBP increased as the pupils got older. BMI may be associated with LBP in childhood and adolescence.

    DOI: 10.1007/s00586-014-3685-0

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  • Risk Factors for Proximal Junctional Kyphosis Associated with Dual-Rod Growing-Rod Surgery for Early-Onset Scoliosis. Reviewed International journal

    Watanabe Kota, Uno Koki, Suzuki Teppei, Kawakami Noriaki, Tsuji Taichi, Yanagida Haruhisa, Ito Manabu, Hirano Toru, Yamazaki Ken, Minami Shohei, Taneichi Hiroshi, Imagama Shiro, Takeshita Katsushi, Yamamoto Takuya, Matsumoto Morio

    J Spinal Disord Tech   29 ( 8 )   E428-33   2014.7

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    STUDY DESIGN: A retrospective, multicenter study. OBJECTIVE:: To identify risk factors for proximal junctional kyphosis (PJK) when treating early-onset scoliosis (EOS) with dual-rod growing-rod (GR) procedure. SUMMARY OF BACKGROUND DATA:: The risk factors for PJK associated with GR treatment for EOS have not been adequately studied. METHODS:: We evaluated clinical and radiographic results from 88 patients with EOS who underwent dual-rod GR surgery in 12 spine centers in Japan. The mean age at the time of the initial surgery was 6.5+/-2.2 years (range, 1.5-9.850% shaded blocky), and the mean follow-up period was 3.9+/-2.6 years (range, 2.0-12.050% shaded blocky). Risk factors for PJK were analyzed by binomial multiple logistic regression analysis. The potential factors analyzed were gender, etiology, age, the number of rod-lengthening procedures, coronal and sagittal parameters on radiographs, the type of foundation (pedicle screws or hooks), the uppermost level of the proximal foundation, and the lowermost level of the distal foundation. RESULTS:: PJK developed in 23 patients (26%); in 19 of these, the proximal foundation became dislodged following PJK. Binomial multiple logistic

    DOI: 10.1097/BSD.0000000000000127

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  • The characteristic clinical symptoms of C-4 radiculopathy caused by ossification of the posterior longitudinal ligament: Case report Reviewed

    Keiichi Katsumi, Akiyoshi Yamazaki, Kei Watanabe, Toru Hirano, Masayuki Ohashi, Naoto Endo

    Journal of Neurosurgery: Spine   20 ( 5 )   480 - 484   2014

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    Cervical radiculopathy of the C2-4 spinal nerves is a rare condition and is poorly documented in terms of clinical symptoms, hindering its detection during initial patient screening based on imaging diagnostics. The authors describe in detail the clinical symptoms and successful surgical treatment of a patient diagnosed with isolated C-4 radiculopathy. This 41-year-old man suffered from sleep disturbance because of pain behind the right ear, along the right clavicle, and at the back of his neck on the right side. The Jackson and Spurling tests were positive, with pain radiating to the area behind the patient's ear. Unlike in cases of radiculopathy involving the C5-8 spinal nerves, no loss of upper-extremity motor function was seen. Magnetic resonance imaging showed foraminal stenosis at the C3-4 level on the right side, and multiplanar reconstruction CT revealed a beak-type ossification of the posterior longitudinal ligament in the foraminal region at the same level. In the absence of intracranial lesions or spinal cord compressive lesions, the positive Jackson and Spurling tests and the C3-4 foraminal stenosis were indicative of isolated C-4 radiculopathy. Microscopic foraminotomy was performed at the C3-4 vertebral level and the ossified lesion was resected. The patient's symptoms completely resolved immediately after surgery. To the authors' knowledge, this report is the first to describe the symptomatic features of isolated C-4 radiculopathy, in a case in which the diagnosis has been confirmed by both radiological findings and surgical outcome. Based on this case study, the authors conclude that the characteristic symptoms of C-4 radiculopathy are the presence of pain behind the ear and in the clavicular region in the absence of upper-limb involvement. ©AANS, 2014.

    DOI: 10.3171/2014.2.SPINE13500

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  • Three-dimensional evaluation of volume change in ossification of the posterior longitudinal ligament of the cervical spine using computed tomography Reviewed

    Tomohiro Izumi, Toru Hirano, Kei Watanabe, Atsuki Sano, Takui Ito, Naoto Endo

    European Spine Journal   22 ( 11 )   2569 - 2574   2013.11

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    Background: Two-dimensional imaging is not adequate for evaluating ossification of the posterior longitudinal ligament (OPLL). This study was designed to evaluate the accuracy of a novel computed tomography (CT)-based three-dimensional (3D) analysis method that we had devised to measure volume changes in OPLL. Subjects and methods: Twenty OPLL patients (12 male and 8 female
    mean age 63.6 years) who were being followed conservatively were examined twice with an interval of at least 1 year between the two scans. The mean interval was 22 (range 12-45) months. A 3D model was created with DICOM data from CT images, using the MIMICS® software to calculate the volume. The mean ossification volume was determined from two measurements. Since ossification size varies widely, evaluation of change in volume is generally affected by the original size. Therefore, the change in ossification volume between the first and second CT examinations was calculated as the annual rate of progression. Results: The type of OPLL was classified as continuous in 3 patients, segmented in 3, and mixed in 14. The mean ossification volume was 1,831.68 mm3 at the first examination and 1,928.31 mm3 at the second, showing a significant mean increase in ossification volume. The mean annual rate of lesion increase was 3.33 % (range 0.08-7.79 %). Conclusion: The 3D method used allowed detailed OPLL classification and quantification of change in the ossified volume. Thus, this method appears to be very useful for quantitative evaluation of OPLL with only minimal measurement error. © 2013 Springer-Verlag Berlin Heidelberg.

    DOI: 10.1007/s00586-013-2989-9

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  • Atypical findings on magnetic resonance imaging in the patients with active pyogenic spondylitis in japanese university hospitals Reviewed

    Toshimi Aizawa, Hiroshi Ozawa, Tomoaki Koakutsu, Takeshi Nakamura, Haruo Kanno, Toru Hirano, Atsuki Sano, Takui Ito, Eiji Itoi

    Tohoku Journal of Experimental Medicine   231 ( 1 )   13 - 19   2013.8

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    Recently, aging population and immuno-compromised patients have been rising in Japan. Accordingly, patients with pyogenic spondylitis have been increasing and may present atypical clinical features. University hospitals treat many elderly patients and patients with poor general condition. Therefore, patients with pyogenic spondylitis treated at two university hospitals were retrospectively investigated to clarify the recent clinical and radiologic characteristics of this infection. There were 30 patients (average age: 68 years) treated in two university hospitals between 2009 and 2010. The onset was acute or subacute in 15 patients, insidious in 7 and unclassified in 8. Culture tests were performed in 25 patients, and the causative microorganisms were identified in 20 patients with the identification rate of 80%, including 4 patients infected by methicillin-resistant staphylococci. Classically, active pyogenic spondylitis is characterized by typical findings on magnetic resonance imaging (MRI): obvious signal decrease in T1-weighted image (WI) and increase in T2WI with contrast enhancement found in most of the bodies of two adjacent vertebrae and the intervening intervertebral disc. Among 29 patients with active pyogenic spondylitis, whose lesions were not in the healing stage, 16 patients demonstrated at least one of the atypical MRI findings
    9 patients showed involvement ≥ 3 vertebrae or only 1 vertebra, 5 showed the signal changes of the lesions involving small, spotty, or faint areas, and 3 showed small vertebral lesions but larger epidural or paraspinal abscesses. In conclusion, currently, about half of the patients with pyogenic spondylitis demonstrate atypical MRI findings in the university hospitals in Japan. © 2013 Tohoku University Medical Press.

    DOI: 10.1620/tjem.231.13

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  • Preoperative evaluation of the vertebral arteries and posterior portion of the circle of Willis for cervical spine surgery using 3-dimensional computed tomography angiography. Reviewed

    Sano Atsuki, Hirano Toru, Watanabe Kei, Izumi Tomohiro, Endo Naoto, Ito Takui, Inagawa Shoichi

    Spine (Phila Pa 1976)   38 ( 15 )   E960 - E967   2013.7

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    STUDY DESIGN: A retrospective analysis using prospectively collected data from 3-dimensional computed tomography angiography (3D-CTA). OBJECTIVE: To investigate the frequency of anomalous vertebral arteries (VA) and variations of the posterior portion of the circle of Willis (PPCW) using 3D-CTA for preventing perioperative iatrogenic vascular complications. SUMMARY OF BACKGROUND DATA: Some studies have reported that preoperative 3D-CTA is useful for determining the VA blood flow in the cervical spine. However, preoperative 3D-CTA has not been used for evaluating PPCW, which functions as vessels collateral to the basilar artery in the case of iatrogenic VA injury. METHODS: The study included 100 consecutive patients (61 males and 39 females; mean age, 60.4 +/- 15.4 yr; range, 11-86 yr) who underwent cervical decompression and/or instrumentation between April 2008 and May 2012. We measured the diameters of the VA (VAD), posterior communicating artery (PCOMD), first segment of the posterior cerebral artery (P1D), and basilar artery (BAD) twice and determined the frequency of anomalous VA and PPCW variations. RESULTS: Hypoplastic VA, hypoplastic PCOM, and hypoplastic P1 were detect

    DOI: 10.1097/BRS.0b013e318296e542

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  • Risk factors for complications associated with growing-rod surgery for early-onset scoliosis. Reviewed

    Watanabe Kota, Uno Koki, Suzuki Teppei, Kawakami Noriaki, Tsuji Taichi, Yanagida Haruhisa, Ito Manabu, Hirano Toru, Yamazaki Ken, Minami Shohei, Kotani Toshiaki, Taneichi Hiroshi, Imagama Shiro, Takeshita Katsushi, Yamamoto Takuya, Matsumoto Morio

    Spine (Phila Pa 1976)   38 ( 8 )   E464 - E468   2013.4

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    STUDY DESIGN: A retrospective multicenter study. OBJECTIVE: To identify risk factors for postoperative complications associated with growing-rod (GR) surgery for early-onset scoliosis (EOS). SUMMARY OF BACKGROUND DATA: Results and complications of GR surgery for EOS have not been adequately studied. METHODS: We evaluated clinical and radiographical results from 88 patients with EOS who underwent GR surgery in 12 spine centers in Japan. The mean age at the time of initial surgery was 6.5 +/- 2.2 years (range, 1.5-9.8 yr) and the mean follow-up period was 3.9 +/- 2.6 years (range, 2.0-12.0 yr). Risk factors for postoperative complications were analyzed using binomial multiple logistic regression analysis. We considered the potential factors of sex, age, number of rod-lengthening procedures, whether a pedicle screw foundation was used, the uppermost level of the proximal foundation and lowermost level of the distal foundation, Cobb angles of the proximal thoracic, main thoracic, and lumbar curves, and the kyphosis angles in the proximal, main thoracic, thoracolumbar, and lumbar spine. Kaplan-Meier analysis was used to determine the complication-free survival rate of GR surgery as a

    DOI: 10.1097/BRS.0b013e318288671a

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  • Variation of the position of the aorta relative to a kyphotic thoracic spine: Safety margin for pedicle screw placement in the adult Japanese population Reviewed

    Masayuki Ohashi, Takui Ito, Toru Hirano, Naoto Endo

    Spine   37 ( 4 )   261 - 265   2012.2

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    Study Design: An analysis of computed tomography images of the spine in adult Japanese patients. Objective: To evaluate the variation of the position of the aorta relative to a spine with a thoracic kyphotic angle and to verify the safety margin for transpedicular screw fixation. Summary of Background Data: Recent studies have suggested that the aorta is positioned more laterally and posteriorly in patients with idiopathic scoliosis than in normal patients
    however, variation of the position of the aorta in thoracic sagittal alignment has not been performed. Methods: T4-T12 vertebrae were studied using computer tomography images in 58 Japanese patients (aged 31-90 years) with normal coronal alignment of the spine. Pedicle diameter, pedicle length, chord length, closest distance from the aorta, and pedicle-aorta angle (PAA) were evaluated using a Mann-Whitney U test and Spearman rank correlation analysis. Results: Pedicle diameter showed an increase in size from T4 (4.7 mm) to T12 (8.2 mm), pedicle length had an almost constant size of about 20 mm, and chord length increased from T4 (37.7 mm) to T12 (47.2 mm). Closest distance from the aorta decreased from T4 (29.6 mm) to T6 (24.6 mm) and then increased to T12 (49.3 mm). PAA increased from T4 (31.5°) to T6 (38.6°) and then decreased to T12 (5.0°). Sagittal curvature showed a correlation with PAA, with an increasing sagittal thoracic Cobb angle related to decreases in PAA at the T5 (r = -0.31, P = 0.034), T6 (r = -0.37, P = 0.008), and T7 (r = -0.29, P = 0.036) levels. Conclusion: The descending aorta is positioned more medially at the T5, T6, and T7 levels in patients with a kyphotic spine. These spatial relationships should be considered when planning pedicle screw insertion for a kyphotic spine. Copyright © 2012 Lippincott Williams &amp
    Wilkins.

    DOI: 10.1097/BRS.0b013e31821cc6b6

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  • Late stress fracture of a well-consolidated strut graft after total spondylectomy in the thoracolumbar spine. Reviewed

    Ito Takui, Endo Naoto, Honma Takao, Hirano Toru

    Spine (Phila Pa 1976)   36 ( 8 )   E551 - E555   2011.4

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    STUDY DESIGN: A retrospective study of three patients of delayed stress fracture of anterior strut graft after total spondylectomy. OBJECTIVE: The aim of this paper is to report a possible risk of removal of instrumentation after total spondylectomy. SUMMARY OF BACKGROUND DATA: Solid fusion of anterior column usually means stable spine and reports of delayed stress fracture of an anterior strut graft are rare. METHODS: The authors reviewed the medical history and imaging data of three patients who suffered late stress fracture after total spondylectomy. RESULTS: All three patients had total spondylectomy as a treatment of malignant tumor of thoracic spine. After removal of posterior instrumentation, they sustained stress fracture of the anterior strut, which is already incorporated well. CONCLUSION: Removal of instrumentation may cause stress fracture of anterior strut grafts after total spondylectomy. Solid fusion of anterior column usually indicates stable spinal column and reported delayed stress fracture of anterior strut graft is rare. The authors reviewed the medical history and images of three cases with late stress fracture after total spondylectomy. All three cases had t

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  • Back pain in adolescents with idiopathic scoliosis: epidemiological study for 43,630 pupils in Niigata City, Japan. Reviewed

    Sato Tsuyoshi, Hirano Toru, Ito Takui, Morita Osamu, Kikuchi Ren, Endo Naoto, Tanabe Naohito

    Eur Spine J   20 ( 2 )   274 - 279   2011.2

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    There have been a few studies regarding detail of back pain in adolescents with idiopathic scoliosis (IS) as prevalence, location, and severity. The condition of back pain in adolescents with IS was clarified based on a cross-sectional study using a questionnaire survey, targeting a total of 43,630 pupils, including all elementary school pupils from the fourth to sixth grade (21,893 pupils) and all junior high pupils from the first to third year (21,737 pupils) in Niigata City (population of 785,067), Japan. 32,134 pupils were determined to have valid responses (valid response rate: 73.7%). In Niigata City, pupils from the fourth grade of elementary school to the third year of junior high school are screened for scoliosis every year. This screening system involves a three-step survey, and the third step of the survey is an imaging and medical examination at the Niigata University Hospital. In this study, the pupils who answered in the questionnaire that they had been advised to visit Niigata University Hospital after the school screening were defined as Scoliosis group (51 pupils; 0.159%) and the others were defined as No scoliosis group (32,083 pupils). The point and lifetime pr

    DOI: 10.1007/s00586-010-1657-6

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  • Low back pain in childhood and adolescence: assessment of sports activities. Reviewed

    Sato Tsuyoshi, Ito Takui, Hirano Toru, Morita Osamu, Kikuchi Ren, Endo Naoto, Tanabe Naohito

    Eur Spine J   20 ( 1 )   94 - 99   2011.1

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    A cross-sectional study that targeted a total of 43,630 pupils in Niigata City, Japan was performed. The objective of the study was to evaluate the association between sports activities and low back pain (LBP) in childhood and adolescence in Japan. Regarding risk factors of LBP, a large number of studies have been conducted that have examined gender differences, height and weight, body mass index, sports time, differences in lifestyle, family history, and mental factors; however, no definitive conclusion has yet been made. A questionnaire survey was conducted using 43,630 pupils, including all elementary school pupils from the fourth to sixth grade (21,893 pupils) and all junior high pupils from the first to third year (21,737 pupils) in Niigata City (population of 785,067). 26,766 pupils who were determined to have valid responses (valid response rate 61.3%) were analyzed. Among the 26,766 pupils with valid responses, 2,591 (9.7%) had LBP at the time of the survey, and 8,588 (32.1%) had a history of LBP. The pupils were divided between those who did not participate in sports activities except the physical education in school (No sports group: 5,486, 20.5%) and those who participat

    DOI: 10.1007/s00586-010-1485-8

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  • Descending aortic injury by a thoracic pedicle screw during posterior reconstructive surgery: a case report. Reviewed

    Watanabe Kei, Yamazaki Akiyoshi, Hirano Toru, Izumi Tomohiro, Sano Atsuki, Morita Osamu, Kikuchi Ren, Ito Takui

    Spine (Phila Pa 1976)   35 ( 20 )   E1064 - E1068   2010.9

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    STUDY DESIGN: Case report. OBJECTIVE: To describe an iatrogenic aortic injury by pedicle screw instrumentation during posterior reconstructive surgery of spinal deformity. SUMMARY OF BACKGROUND DATA: Iatrogenic major vascular injuries during anterior instrumentation procedures have been reported by several authors, but there have been few reports regarding iatrogenic major vascular injuries during posterior instrumentation procedures. METHODS: A 57-year-old woman with thoracolumbar kyphosis due to osteoporotic T12 vertebral fracture underwent posterior correction and fusion (T10-L2), using segmental pedicle screw construct concomitant with T12 pedicle subtraction osteotomy. Postoperative routine plain radiographs and computed tomography myelography demonstrated a misplaced left T10 pedicle screw, which was in contact with the posteromedial aspect of the thoracic aorta, and suspected penetration of the aortic wall. The patient underwent removal of the pedicle screw, and repair of the penetrated aortic wall through a simultaneous anterior-posterior approach. RESULT: The patient tolerated the procedure well without neurologic sequelae, and was discharged several days after removal

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  • Percutaneous intralesional injection of calcitonin and methylprednisolone for treatment of an aneurysmal bone cyst at C-2 Reviewed

    Masayuki Ohashi, Takui Ito, Toru Hirano, Naoro Endo

    JOURNAL OF NEUROSURGERY-PEDIATRICS   2 ( 5 )   365 - 369   2008.11

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    An aneurysmal bone cyst (ABC) is a rare skeletal tumor that accounts for similar to 1% of all bone tumors. A spinal location for an ABC is very rare. Methods for treatment of an ABC include resection, curettage, embolization, and intralesional injection of a variety of agents. The patient in this case was a 9-year-old girl presenting with neck pain who was diagnosed with an ABC involving the C-2 spinal level. Percutaneous intralesional injections of calcitonin and methylprednisolone were performed. Two years and 7 months after the initial injection, a CT scan showed massive bone formation and cortical thickening without a change in the size of the lesion. To the authors' knowledge, this is the third reported case of intralesional injection of calcitonin and methylprednisolone for treatment of an ABC. This method is safe and effective, and is an important alternative to surgery, especially when a surgical procedure is technically difficult or unsafe in high-risk patients. (DOI: 10.3171/PED.2008.2.11.365)

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  • Low back pain in childhood and adolescence: a cross-sectional study in Niigata City. Reviewed

    Sato Tsuyoshi, Ito Takui, Hirano Toru, Morita Osamu, Kikuchi Ren, Endo Naoto, Tanabe Naohito

    Eur Spine J   17 ( 11 )   1441 - 1447   2008.11

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    A cross-sectional study targeted a total of 43,630 pupils in Niigata City, Japan was performed. The objective was to clarify the present incidence of low back pain (LBP) in childhood and adolescence in Japan. It has recently been recognized that LBP in childhood and adolescence is also as common a problem as that for adults and most of these studies have been conducted in Europe, however, none have so far been made in Japan. A questionnaire survey was conducted using 43,630 pupils, including all elementary school students from the fourth to sixth grade (21,893 pupils) and all junior high students from the first to third year (21,737 pupils) in Niigata City (population of 785,067) to examine the point prevalence of LBP, the lifetime prevalence, the gender differences, the age of first onset of LBP in third year of junior high school students, the duration, the presence of recurrent LBP or not, the trigger of LBP, and the influences of sports and physical activities. In addition, the severity of LBP was divided into three levels (level 1: no limitation in any activity; level 2: necessary to refrain from participating in sports and physical activities, and level 3: necessary to be ab

    DOI: 10.1007/s00586-008-0788-5

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  • Indications for cervical pedicle screw instrumentation in nontraumatic lesions. Reviewed

    Hasegawa Kazuhiro, Hirano Toru, Shimoda Haruka, Homma Takao, Morita Osamu

    Spine (Phila Pa 1976)   33 ( 21 )   2284 - 2289   2008.10

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    STUDY DESIGN: Retrospective clinical study. OBJECTIVE: To evaluate clinical results of patients with nontraumatic cervical lesions treated by cervical pedicle screw (PS) fixation and to discuss the surgical indications. SUMMARY OF BACKGROUND DATA: PS fixation provides an outstanding stability for cervical lesions with instability. This technique, however, has a potential risk of vertebral artery, spinal cord, and nerve root injuries, which may be catastrophic. METHODS: Fifty-eight patients were divided into 2 groups: patients with cervical kyphosis with vertebral destructive lesions (group D, n = 38) and those without destructive lesions (group ND, n = 20). Clinical results of the 2 groups were compared. The results of decompression and PS fixation for cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL) in this series were also compared with those of previous laminoplasty alone in patients with CSM and OPLL. RESULTS: Nape pain in group D improved in 86.7% of the patients. Overall neurologic status was improved in both groups. Bony fusion was confirmed in 100% of the cases that were alive in group D and 95% in group ND. Eight complic

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  • Thoracic myelopathy due to idiopathic epidural ossifications in a child: a case report. Reviewed

    Urakawa Takaaki, Ito Takui, Hirano Toru, Watanabe Kei, Uchiyama Seiji

    Spine (Phila Pa 1976)   33 ( 14 )   E478 - E481   2008.6

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    STUDY DESIGN: A rare case of thoracic myelopathy due to epidural ossification in a child. OBJECTIVE: To determine a differential diagnosis of thoracic myelopathy. SUMMARY OF BACKGROUND DATA: Ectopic ossification is one of the common lesions that can cause thoracic myelopathy. The majority of the cases occur in adults and ossification usually occurs in ligamentous tissues. To the authors' knowledge, no published reports in the English literature have described a case of thoracic myelopathy in a child caused by ectopic epidural and nonligamentous ossification. METHODS: A 15 year-old girl presented with a chief complaint of bilateral numbness of the thigh and gait disturbance. RESULTS: Computed tomography demonstrated 3 islands of epidural ossifications that surrounded the dural sac from T2-T4 and compressed the spinal cord. These lesions, which were not due to ossification of the ligament, were surgically resected. After resection, her symptoms completely disappeared. Histologic diagnosis of the removed specimen was fibro-osseous tissue. Radiologic examination demonstrated no recurrence of the lesion 6 years after surgery. CONCLUSION: We describe this condition as idiopathic epidura

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  • Surgical results and related factors for ossification of posterior longitudinal ligament of the thoracic spine: A multi-institutional retrospective study Reviewed

    Morio Matsumoto, Kazuhiro Chiba, Yoshiaki Toyama, Katsushi Takeshita, Atsushi Seichi, Kozo Nakamura, Jun Arimizu, Shunsuke Fujibayashi, Shigeru Hirabayashi, Toru Hirano, Motoki Iwasaki, Kouji Kaneoka, Yoshiharu Kawaguchi, Kosei Ijiri, Takeshi Maeda, Yukihiro Matsuyama, Yasuo Mikami, Hideki Murakami, Hideki Nagashima, Kensei Nagata, Shinnosuke Nakahara, Yutaka Nohara, Shiro Oka, Keizo Sakamoto, Yasuo Saruhashi, Yutaka Sasao, Katsuji Shimizu, Toshihiko Taguchi, Makoto Takahashi, Yasuhisa Tanaka, Toshikazu Tani, Yasuaki Tokuhashi, Kenzo Uchida, Kengo Yamamoto, Masashi Yamazaki, Toru Yokoyama, Munehito Yoshida, Yuji Nishiwaki

    Spine   33 ( 9 )   1034 - 1041   2008.4

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    STUDY DESIGN. Retrospective multi-institutional study OBJECTIVE. To describe the surgical outcomes in patients with ossification of the posterior longitudinal ligament in the thoracic spine (T-OPLL) and to clarify factors related to the surgical outcomes. SUMMARY OF BACKGROUND DATA. Detailed analyses of surgical outcomes of T-OPLL have been difficult because of the rarity of this disease. METHODS. The subjects were 154 patients with T-OPLL who were surgically treated at 34 institutions between 1998 and 2002. The surgical procedures were laminectomy in 36, laminoplasty in 51, anterior decompression via anterior approach in 25 and via posterior approach in 29, combined anterior and posterior fusion in 8, and sternum splitting approach in 5 patients. Instrumentation was conducted in 52 patients. Assessments were made on (1) The Japanese Orthopedic Association (JOA) scores (full score, 11 points), its recovery rates, (2) factors related to surgical results, and (3) complications and their consequences. RESULTS. (1) The mean JOA score before surgery was 4.6 ± 2.0 and, 7.1 ± 2.5 after surgery. The mean recovery rate was 36.8% ± 47.4%. (2) The recovery rate was 50% or higher in 72 patients (46.8%). Factors significantly related to this were location of the maximum ossification (T1-T4) (odds ratio, 2.43-4.17) and the use of instrumentation (odds ratio, 3.37). (3) The frequent complications were deterioration of myelopathy immediately after surgery in 18 (11.7%) and dural injury in 34 (22.1%) patients. CONCLUSION. The factors significantly associated with favorable surgical results were maximum ossification located at the upper thoracic spine and use of instrumentation. T-OPLL at the nonkyphotic upper thoracic spine can be treated by laminoplasty that is relatively a safe surgical procedure for neural elements. The use of instrumentation allows correction of kyphosis or prevention of progression of kyphosis, thereby, enhancing and maintaining decompression effect, and its use should be considered with posterior decompression. © 2008 Lippincott Williams &amp
    Wilkins, Inc.

    DOI: 10.1097/BRS.0b013e31816c913b

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  • Significant correlation between cerebrospinal fluid nitric oxide concentrations and neurologic prognosis in incomplete cervical cord injury. Reviewed

    Hosaka Noboru, Kimura Shinji, Yamazaki Akiyoshi, Wang Xianjun, Denda Hiroshi, Ito Takui, Hirano Toru, Endo Naoto

    Eur Spine J   17 ( 2 )   281 - 286   2008.2

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    In animal models of spinal cord injury (SCI), inducible NO (nitric oxide) synthase is expressed in the spinal cord immediately after sustaining SCI. Excessive NO production has cytotoxic effects and induces neuronal apoptosis, causing neural degeneration and neurodysfunction in the spinal cord. Little is known, however, about the relationship between NO(x) (NO metabolites: nitrite and nitrate) levels in the cerebrospinal fluid (CSF) and neurologic severity or recovery in clinical cases. The objective of the present study was to examine the correlation between CSF NO(x) levels and neurologic severity or recovery in SCI. Twenty-five patients with incomplete cervical cord injury (CCI) were examined. Eight cases were treated conservatively (non-operated group). Seventeen cases underwent surgical intervention (operated group). NO(x) levels in the CSF were measured using the Griess method. The severity of the neurologic impairment was assessed using Frankel's classification and the American Spinal Injury Association motor score (ASIA MS). The degree of neurologic recovery was assessed using Frankel's classification and the ASIA motor recovery percentage (MRP). There was no significant d

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  • Cross-cultural comparison of the Scoliosis Research Society Outcomes Instrument between American and Japanese idiopathic scoliosis patients: Are there differences? Reviewed

    Kei Watanabe, Lawrence G. Lenke, Keith H. Bridwell, Kazuhiro Hasegawa, Toru Hirano, Naoto Endo, Gene Cheh, Yongjung J. Kim, Marsha Hensley, Georgia Stobbs, Linda Koester

    Spine   32 ( 24 )   2711 - 2714   2007.11

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    STUDY DESIGN. A comparative study. OBJECTIVE. To report a preliminary evaluation of the Scoliosis Research Society Outcomes Instrument (SRS-24) and determine whether differences in baseline scores exist between American and Japanese patients with idiopathic scoliosis. SUMMARY OF BACKGROUND DATA. Because the SRS outcomes instrument was primarily introduced for the American population, baseline scores in the Japanese population might differ from the American population. A comparative study using the SRS instrument between American and Japanese patients with idiopathic scoliosis has not been reported. METHODS. Two comparable groups of 100 idiopathic scoliosis patients before spinal fusion were separated into American (A) and Japanese (J). There were no statistically significant differences between the groups for gender (A: 9 men/91 women vs. J: 13 men/87 women), age (A: 15.0 ± 2.4 vs. J: 14.9 ± 3.8), main curve location (A: 77 thoracic/23 lumbar, J: 76 thoracic/24 lumbar), main curve Cobb angle (A: 50.5 ± 5.2 vs. J: 51.1 ± 8.7), and thoracic kyphosis (A: 20.9 ± 14.3 vs. J: 19.9 ± 12.1) (P &gt
    0.05, for all comparisons). Patients were evaluated using the first section of the SRS-24 which was divided into 4 domains: total pain, general self-image, general function, and activity. SRS-24 scores were statistical compared in individual domains and questions using the Mann-Whitney U test. RESULTS. American patients had significantly lower scores in pain (P &lt
    0.0001, A: 3.7 ± 0.8 vs. J: 4.3 ± 0.4), function (P &lt
    0.01, A: 3.9 ± 0.6 vs. J: 4.2 ± 0.5), and activity (P &lt
    0.0001, A: 4.5 ± 0.8 vs. J: 4.9 ± 0.3) domains compared with Japanese patients. Japanese patients had significantly lower scores in the self-image (P &lt
    0.0001, A: 4.0 ± 0.7 vs. J: 3.5 ± 0.5) domain. With regard to individual questions, there were significant differences in the scores between the 2 groups for all questions except 5 and 13 (P &lt
    0.05, for all comparisons). CONCLUSION. SRS-24 scores in the Japanese idiopathic scoliosis population differed from that of the American population. Japanese patients had less back pain, a negative self-image regarding back deformity, higher general physical function, and daily activity. It is highly probable that patient's perceptions differ due to cultural differences, which affect SRS-24 scores so a cross-cultural comparison of the SRS instrument content is necessary in the future. © 2007 Lippincott Williams &amp
    Wilkins, Inc.

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  • Evaluation of postoperative residual spinal deformity and patient outcome in idiopathic scoliosis patients in Japan using the Scoliosis Research Society Outcomes Instrument Reviewed

    Kei Watanabe, Kazuhiro Hasegawa, Toru Hirano, Seiji Uchiyama, Naoto Endo

    Spine   32 ( 5 )   550 - 554   2007.3

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    STUDY DESIGN. This study clarifies the correlation between the components of the Scoliosis Research Society Outcomes Instrument (SRS-24) and the radiographic parameters after surgery in Japanese idiopathic scoliosis patients. OBJECTIVES. To investigate the correlation between the magnitude of back deformity after scoliosis surgery and the components of the SRS-24. SUMMARY OF BACKGROUND DATA. Patient outcomes for Japanese scoliosis patients using the SRS-24 have not been fully investigated. METHODS. Idiopathic scoliosis patients (n = 81) who were treated with surgery and followed up for more than 2 years were evaluated. Radiographic examination included Cobb angle, rotation angle of apical vertebrae, and translation of the C7 vertebra from the center sacral line on the coronal plane. In addition, the score of one new question regarding postoperative scar was investigated and compared with that of the individual SRS-24 domains. RESULTS. A comparison of the SRS-24 and radiographic results revealed a significant inverse correlation between total pain and the postoperative correction of the rotation angle in the thoracic curve (rs = 0.27
    P &lt
    0.05). General self-image was inversely correlated with the Cobb angle (rs = -0.23
    P &lt
    0.05) and the rotation angle (rs = -0.30
    P &lt
    0.01) in the thoracic curve. Self-image after surgery was positively correlated with the correction degree of the thoracic Cobb angle (rs = 0.27
    P &lt
    0.05)
    60% of patients had some concerns regarding postoperative scar, and the concerned patients demonstrated significantly lower scores in the pain and general self-image domains (P &lt
    0.05) than the unconcerned patients did. CONCLUSION. Patients with a greater Cobb angle or rotation angle in the thoracic curve had a negative self-image. Self-image improved after surgery by greater correction of the thoracic Cobb angle. Thoracic scoliotic deformity with prominence should be substantially reduced by the surgical treatment to improve satisfaction rates and self-imageregarding back appearance. Additionally, physicians should pay more attention to patients' concern regarding their postoperative scars to obtain better outcomes. © 2007 Lippincott Williams &amp
    Wilkins, Inc.

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  • Margin-free spondylectomy for extended malignant spine tumors: Surgical technique and outcome of 13 cases Reviewed

    Kazuhiro Hasegawa, Takao Homma, Toru Hirano, Akira Ogose, Tetsuo Hotta, Yoichi Yajiri, Junji Nagano, Yoshiya Inoue

    Spine   32 ( 1 )   142 - 148   2007.1

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    STUDY DESIGN. Description of surgical technique and retrospective review of 13 cases. OBJECTIVES. To describe the surgical technique of margin-free spondylectomy and the outcome of 13 cases and to discuss the advantages and limitations of the procedure. SUMMARY OF BACKGROUND DATA. Recently, spondylectomy became a standard procedure by several pioneers. For extended malignant spine tumors involving pedicles or epidural space, however, performing an "en bloc" resection with a tumor-free margin remains a challenge. METHODS. Our procedure consists of a combined anterior and posterior procedure with one or two stages. In the anterior procedure, tumor vertebrae are covered by the pleura or psoas muscles as a barrier. The posterior procedure includes decompression through the intact posterior elements, coverage of the tumor with all possible soft tissue barriers, and en bloc extirpation by rotating the tumor vertebrae around the spinal cord. We performed this procedure in 13 cases: 3 chondrosarcoma, 3 giant cell tumor, 1 osteosarcoma, 1 chordoma, and 5 metastases. RESULTS. Neurologic status and pain improved in all cases except asymptomatic cases. There was no local recurrence, except in 2 cases (chondrosarcoma with extirpation of 5 vertebrae, chordoma with multiple previous surgeries). Two cases of chondrosarcoma were disease-free 14 years and 13 years after surgery, respectively. CONCLUSION. Although the best chance for a cure in extended malignant tumors of the spine is realized through wide resection, the procedure is not yet standardized. Margin-free spondylectomy is technically demanding, but the procedure can be used with a confidence as a more radical surgery for tumors extending to the epidural space and the unilateral pedicle. A key to success is the surgical technique, including a 360° dissection around the tumor vertebrae, instrumentation, and removal of the lesion with all possible soft tissues maintained intact to function as a barrier, like the dura mater. © 2007 Lippincott Williams &amp
    Wilkins, Inc.

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  • Anterior spinal decompression and fusion for cervical flexion myelopathy in young patients. Reviewed

    Watanabe Kei, Hasegawa Kazuhiro, Hirano Toru, Endo Naoto, Yamazaki Akiyoshi, Homma Takao

    J Neurosurg Spine   3 ( 2 )   86 - 91   2005.8

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    OBJECT: The mechanism underlying cervical flexion myelopathy (CFM) is unclear. The authors report the results of anterior decompression and fusion (ADF) in terms of neurological status and radiographically documented status in young patients and discuss the pathophysiological mechanism of the entity. METHODS: Twelve patients underwent ADF in which autogenous iliac bone graft was placed. The fusion area was one segment in four cases, two segments in seven, and three segments in one. Neurological status, as determined by the Japanese Orthopaedic Association (JOA) score, radiographic findings, and intraoperative findings were evaluated. The mean follow-up period was 63.3 months (range 20-180 months). Grip strength was significantly improved and sensory disturbances resolved completely. Intrinsic muscle atrophy, however, persisted in all patients at the final follow-up examination. Local kyphosis in the flexed-neck position at the fusion levels was corrected by surgery. Preoperative computerized tomography myelography revealed that the cord compression index, which was calculated by anteroposterior and transverse diameters of the spinal cord, decreased to 33 +/- 6.2% in the flexed-ne

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  • Use of the scoliosis research society outcomes instrument to evaluate patient outcome in untreated idiopathic scoliosis patients in Japan: part I: comparison with nonscoliosis group: preliminary/limited review in a Japanese population. Reviewed

    Watanabe Kei, Hasegawa Kazuhiro, Hirano Toru, Uchiyama Seiji, Endo Naoto

    Spine (Phila Pa 1976)   30 ( 10 )   1197 - 1201   2005.5

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    STUDY DESIGN: This preliminary study evaluates untreated Japanese patients with idiopathic scoliosis using the Scoliosis Research Society Outcomes Instrument (SRS-24). OBJECTIVES: To determine the baseline patient outcome score using the SRS-24 for untreated Japanese scoliosis patients compared with a nonscoliosis group. SUMMARY OF BACKGROUND DATA: The SRS instrument with 24 questions was developed to help evaluate patient-perceived outcomes of idiopathic scoliosis treatment. Evaluation of untreated Japanese idiopathic scoliosis patients using the SRS instrument has not been reported. METHODS: Japanese idiopathic scoliosis patients (n = 141) (mean age, 13.6 years; range, 10-17 years) with a Cobb angle of more than 20 degrees who were not treated with a brace or surgery, were evaluated in comparison with a nonscoliosis group (healthy junior high school students; n = 72) using the SRS-24. The scoliosis group was categorized as mild deformity group with a major curve Cobb angle of less than 30 degrees, moderate deformity group with 30 degrees to 49 degrees, and severe deformity group with more than 50 degrees. The patients were evaluated using section 1 (15 questions) of the SRS-24,

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  • Use of the scoliosis research society outcomes instrument to evaluate patient outcome in untreated idiopathic scoliosis patients in Japan: part II: relation between spinal deformity and patient outcomes. Reviewed

    Watanabe Kei, Hasegawa Kazuhiro, Hirano Toru, Uchiyama Seiji, Endo Naoto

    Spine (Phila Pa 1976)   30 ( 10 )   1202 - 1205   2005.5

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    STUDY DESIGN: This study clarifies the relation between the results of the Scoliosis Research Society Outcomes Instrument (SRS-24) and radiographic parameters of back deformity in Japanese idiopathic scoliosis patients. OBJECTIVES: To investigate the relation between magnitude of back deformity and results of the SRS-24 in untreated patients. SUMMARY OF BACKGROUND DATA: In idiopathic scoliosis, it is necessary to clarify the relation between patient-perceived outcomes of the deformity and magnitude of back deformity before considering treatment. The relation between the magnitude of spinal deformity and outcomes of untreated patients, however, has not been fully investigated. METHODS: Patients (n = 166) under 30 years of age with untreated scoliosis were evaluated. Radiologic examination included Cobb angle, rotation angle of apical vertebrae, and translation of C7 vertebra from the central sacral line (C7 translation) on the coronal plane. Patient evaluation using section 1 (15 questions) of the SRS-24 was compared with radiologic findings using Spearman's correlation coefficient by rank (rs). RESULTS: The average pain domain score was 27.0 +/- 2.2 points, general self-image 9.9 +

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  • Tissue mineralization is increased following 1-year treatment with high doses of bisphosphonates in dogs Reviewed

    DB Burr, L Miller, M Grynpas, JL Li, A Boyde, T Mashiba, T Hirano, CC Johnston

    BONE   33 ( 6 )   960 - 969   2003.12

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    Suppression of bone turnover using anti-resorptive agents such as bisphosphonates prevents bone loss but also may increase tissue mineralization. This may make the bone more prone to initiate microcracks. The objective of this study was to determine whether suppression of remodeling caused by treatment of dogs for 1 year with five times the clinical dose of either alendronate or risedronate is associated with increased tissue mineralization and whether it changes the nature of the mineral crystal. Thirty-five dogs were divided into three weight-matched groups and treated daily for I year with a subcutaneous injection of saline (CON, n = 12), oral risedronate (RIS, 0.5 mg/kg/day, n = 11), or oral alendronate (ALN, 1.0 mg/kg/day, n = 12). Density fractionation, peripheral quantitative computerized tomography (pQCT), and quantitative backscattered electron microscopy (qBSE) were used to evaluate changes in mineral content of bone tissue from the vertebrae or ribs. Infrared microspectroscopy (IR) and X-ray diffraction were used to assess the quality of the mineral and some aspects of collagen structure in the thoracic vertebrae and iliac crest. Following 12 months of treatment, there was a significant shift toward higher density bone in both ALN (P = 0.04) and RIS (P = 0.002) by density fractionation methods. IR, pQCT, and qBSE did not detect any significant differences in mineralization, probably because of their lower sensitivity and/or because of the smaller region of interest they sample. No significant differences were found in the maturity of the mineral crystals or in their length or size. We conclude that treatment for 1 year with high doses of bisphosphonates which suppress bone remodeling up to 90% increases tissue mineralization, but does not change the nature of the mineral crystal. (C) 2003 Elsevier Inc. All rights reserved.

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  • Canine cancellous bone microarchitecture after one year of high-dose bisphosphonates Reviewed

    M Ding, JS Day, DB Burr, T Mashiba, T Hirano, H Weinans, DR Sumner, Hvid, I

    CALCIFIED TISSUE INTERNATIONAL   72 ( 6 )   737 - 744   2003.6

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    We examined the effects of one-year high-dose bisphosphonates (risedronate 0.5 mg/kg/day or alendronate 1.0 mg/kg/day) on the three-dimensional (3-D) microstructural and mechanical properties of canine cancellous bone. A high-resolution micro-CT scanner was used to scan cubic specimens produced from the first lumbar vertebrae. Microstructural properties of the specimens were calculated directly from the 3-D datasets and the mechanical properties of the specimens were determined. Our data demonstrate significant microarchitectural changes in the bisphosphonate-treated cancellous bone that was typically plate-like, denser, with thicker and more trabeculae compared with those of the controls. Consistent with architectural changes, the Young's moduli of cancellous bone increased in all three directions with the greatest increase in primary axial loading (cephalo-caudal) direction after treatment. Our results suggest a bone remodeling-adaptation mechanism stimulated by bisphosphonates that increases bone volume fraction, thickens trabeculae, changes trabeculae towards more plate-like, and increases mechanical properties. The secondary degree of anisotropy contributed significantly to the explained variance in bone strength, and the primary or tertiary degree of anisotropy improved the explanation of variances for Young's moduli, i.e., 79% of strength variances or 74-83% of modulus variances could be explained by the combined anisotropy and bone volume fraction. These significant improvements of cancellous bone architecture provide a rationale for the clinical observation that fracture risk decreased by 50% in the first year of bisphosphonate therapy with only a 5% increase in bone mineral density. We conclude that bisphosphonates enhance mechanical properties and reduce fracture risk by improving architectural anisotropy of cancellous bone 3-D microarchitecture.

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  • Effects of surgical treatment for cervical spondylotic myelopathy in patients > or = 70 years of age: a retrospective comparative study. Reviewed

    Hasegawa Kazuhiro, Homma Takao, Chiba Yoshikazu, Hirano Toru, Watanabe Kei, Yamazaki Akiyoshi

    J Spinal Disord Tech   15 ( 6 )   458 - 460   2002.12

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    The objective of this study was to compare efficacy of cervical surgery for myelopathy in patients > or = 70 and < or = 60 years of age. Forty patients > or = 70 years and 50 patients < or = 60 years of age with MRI and CT proven myelopathy were neurologically assessed using the JOA score. Three operative procedures were performed: anterior spinal fusion, laminoplasty, and laminectomy. Postoperatively, patients exhibited comparable outcomes irrespective of age or operative procedure performed. The only exception was the increase in postoperative neurologic complications noted for the older individuals with greater comorbidities.

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  • Effects of high-dose etidronate treatment on microdamage accumulation and biomechanical properties in beagle bone before occurrence of spontaneous fractures Reviewed

    T Mashiba, CH Turner, T Hirano, MR Forwood, DS Jacob, CC Johnston, DB Burr

    BONE   29 ( 3 )   271 - 278   2001.9

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    We recently demonstrated that suppressed bone remodeling allows microdamage to accumulate and causes reductions in some mechanical properties. However, in our previous study, I year treatment with high-dose etidronate (EHDP) did not increase microdamage accumulation in most skeletal sites of dogs in spite of complete remodeling suppression and the occurrence of spontaneous fractures of ribs and/or thoracic spinous processes. This study evaluates the effects of EHDP on microdamage accumulation and biomechanical properties before fractures occur. Thirty-six female beagles, 1-2 years old, were treated daily for 7 months with subcutaneous injections of saline vehicle (CNT) or EHDP at 0.5 (E-low) or 5 mg/kg per day (E-high). After killing, bone mineral measurement, histomorphometry, microdamage analysis, and biomechanical testing were performed. EHDP treatment suppressed intracortical and trabecular remodeling by 60%-75% at the lower dose, and by 100% at the higher dose. Osteoid accumulation caused by a mineralization deficit occurred only in the E-high group, and this led to a reduction of mineralized bone mass. Microdamage accumulation increased significantly by two- to fivefold in the rib, lumbar vertebra, ilium, and thoracic spinous process in E-low, and by twofold in the lumbar vertebra and ilium in E-high. However, no significant increase in damage accumulation was observed in ribs or thoracic spinous processes in E-high where fractures occur following 12 months of treatment. Mechanical properties of lumbar vertebrae and thoracic spinous processes were reduced significantly in both E-low and E-high. These findings suggest that suppression of bone remodeling by EHDP allows microdamage accumulation, but that osteoid accumulation reduces production of microdamage. (Bone 29:271-278; 2001) (C) 2001 by Elsevier Science Inc. All rights reserved.

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  • Anabolic effects of human biosynthetic parathyroid hormone fragment (1-34), LY333334, on remodeling and mechanical properties of cortical bone in rabbits. Reviewed

    Toru Hirano

    1999.3

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  • Fracture risk during pedicle screw insertion in osteoporotic spine. Reviewed

    Hirano T, Hasegawa K, Washio T, Hara T, Takahashi H

    J Spinal Disord   11 ( 6 )   493 - 497   1998.12

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    Although using a larger screw can enhance the stability of screw-bone interface in pedicular screw instrumentation, it may cause pedicle fracture during screw insertion in osteoporotic spine. We investigated structural changes of the pedicle with the advance of osteoporosis and its implication for the risk of pedicle fracture. Bone mineral density of trabecular, subcortical, and cortical bone of pedicle in an osteoporotic group, assessed by peripheral quantitative computed tomography, was significantly lower than that of those in the normal group. Cortical thickness also declined. There were no pedicle fractures in normal vertebrae, but seven (41.2%) fractures were observed among 17 pedicles in osteoporotic vertebrae in which bone mineral density measured with dual-energy x-ray absorptiometry was <0.7 g/cm2 and screw diameter >70% of the outer diameter of the pedicle. Our results suggest that screw diameter should not exceed 70% of the outer diameter of the pedicle in the case of osteoporosis in which vertebral bone mineral density is <0.7 g/cm2.

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  • Structural characteristics of the pedicle and its role in screw stability. Reviewed

    Hirano T, Hasegawa K, Takahashi H E, Uchiyama S, Hara T, Washio T, Sugiura T, Yokaichiya M, Ikeda M

    Spine (Phila Pa 1976)   22 ( 21 )   2504 - 9; discussion 2510   1997.11

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    STUDY DESIGN: Cross-sectional regional bone mineral density of the pedicle was measured by peripheral quantitative computed tomography. Biomechanical tests were performed to clarify the role of the pedicle in screw stability. OBJECTIVES: To identify the structural characteristics of the pedicle that supports pedicle screw stability and the differences in these characteristics between normal and osteoporotic vertebrae. SUMMARY OF BACKGROUND DATA: The pedicle screw is an essential component of many systems used to align the spine. The contribution of the pedicle to screw stability, however, has not been fully investigated. METHODS: Trabecular, subcortical, and cortical bone mineral density and the area of the pedicle were measured by peripheral quantitative computed tomography. Bone mineral density also was recalculated in four circumferential layers. These parameters were compared between normal and osteoporotic individuals. The relative contribution of the pedicle to screw stability was evaluated by caudocephalad and pull-out loading in a vertebra with or without its body. RESULTS: Inner trabecular, middle subcortical, and outer cortical bone mineral density and cortical bone are

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  • An experimental study of a combination method using a pedicle screw and laminar hook for the osteoporotic spine. Reviewed

    Hasegawa K, Takahashi H E, Uchiyama S, Hirano T, Hara T, Washio T, Sugiura T, Youkaichiya M, Ikeda M

    Spine (Phila Pa 1976)   22 ( 9 )   958 - 62; discussion 963   1997.5

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    STUDY DESIGN: Using human cadaver spines, the authors compared the effect of using a combination of pedicle screw and laminar hook on the same vertebra with that of using a pedicle screw alone in reference to bone mineral density of the vertebra under nondestructive cyclic loading. OBJECTIVES: To quantify stiffness obtained by pedicle screw alone and by the combination method and to clarify a relationship between stiffness obtained by each instrumentation method and bone mineral density of the vertebra. SUMMARY OF BACKGROUND DATA: The use of pedicle screws apparently improves the union rate of spinal fusion. Instrumentation failures sometimes occur, however, such as loosening or loss of correction of the spine, especially in patients with osteoporosis. Some augmentation method in instrumentation is necessary to overcome bone fragility in the osteoporotic spine. METHODS: Thirteen cadaver lumbar vertebrae were used for this study. Bone mineral density was measured by dual-energy X-ray absorptiometer. After separating each vertebrae, the pedicle screw was screwed into a vertebra. Five cycles of cephalocaudal loading were performed to the shank of the screw with a cross-head speed of

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  • Reductions in bone strength after fluoride treatment are not reflected in tissue-level acoustic measurements. Reviewed

    Turner C H, Takano Y, Hirano T

    Bone   19 ( 6 )   603 - 607   1996.12

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    Acoustic velocity measurements are used to estimate tissue-level bone strength after fluoride therapy for osteoporosis. However, acoustic measurements provide information about elasticity, not strength, and bone elasticity does not necessarily correlate with bone strength at a tissue level. The current study was undertaken to evaluate the effects of fluoride treatment on tissue-level acoustic velocities, and to determine the relationship between acoustic velocity and bone strength measured in the femur, femoral neck, and spine. Young adult rabbits were treated with either 0 or 100 parts per million of fluoride in their drinking water for six months. After treatment, the bones were harvested for measurement of tissue fluoride, bone strength, and acoustic properties. Acoustic velocities were measured in the femoral midshaft using an acoustic microscope with a 50 MHz transducer. Both longitudinal and transverse velocities were measured. After the initial acoustic measurements the bone specimens were treated to remove either the organic matrix or mineral, and the acoustic measurements were repeated. Fluoride treatment increased bone fluoride levels 7-8 fold and reduced all biomechan

    DOI: 10.1016/S8756-3282(96)00306-7

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Research Projects

  • 腰椎固定術におけるロッド固定のための結束材料の可能性について

    2003.4 - 2004.3

    System name:受託研究

    Awarding organization:(財) にいがた産業創造機構

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    Grant type:Competitive

    Grant amount:\1000000

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  • チタンメッシュプレートによる小動物複雑骨折部の固定可能性について

    2003.4 - 2004.3

    System name:受託研究

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    Grant type:Competitive

    Grant amount:\1000000

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