Details of a Researcher - Matsumoto, Morio

Papers - Matsumoto, Morio

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SNP rs11190870 near LBX1 is associated with adolescent idiopathic scoliosis in southern Chinese

Fan Yan Hui, Song You Qiang, Chan Danny, Takahashi Yohei, Ikegawa Shiro, Matsumoto Morio, Kou Ikuyo, Cheah Kathryn S E, Sham Pak, Cheung Kenneth M C, Luk Keith D K

Journal of Human Genetics 57 ( 4 ) 244 - 246 2012.04

ISSN 1434-5161

A study was conducted to validate the most significant single nucleotide polymorphism (SNP) from a genome-wide association study of Japanese adolescent idiopathic scoliosis (AIS) patients in an independent southern Chinese population. In total, 300 AIS patients fulfilled the clinical criteria and 788 controls with MRI scans of the spine were included in the replication study. We employed case-control analysis to study the association of SNP rs11190870 near LBX1 (ladybird homeobox 1) with AIS in a southern Chinese population. The results suggest that SNP rs11190870 is significantly associated with AIS (P=9.1 × 10^-10; odds ratio1.85; 95% confidence interval=1.52-2.25). The results of this study confirm that SNP rs11190870 is associated with AIS. © 2012 The Japan Society of Human Genetics All rights reserved.

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Morphologic evaluation of the thoracic vertebrae for safe free-hand pedicle screw placement in adolescent idiopathic scoliosis

Cui Guanyu, Watanabe Kota, Hosogane Naobumi, Tsuji Takashi, Ishii Ken, Nakamura Masaya, Toyama Yoshiaki, Chiba Kazuhiro, Lenke Lawrence G., Matsumoto Morio

Surgical and Radiologic Anatomy 34 ( 3 ) 209 - 216 2012.04

ISSN 0930-1038

Objective To evaluate the morphologic characteristics of the thoracic pedicle with regard to safe free-hand thoracic pedicle screw placement, based on multi-planar reconstruction CT images. Methods Thirty adolescent idiopathic scoliosis (AIS) patients who had undergone posterior corrective surgery for major thoracic curve were included in this study. Reconstructed CT axial images at each thoracic vertebra were used to measure: (1) the shortest distance from an entry point to the ventral cortex of the lamina (critical distance), and (2) the distance from the entry point to the tangent of the spinal canal at the medial wall of the pedicle (safe distance). The critical length was defined as the distance between the critical distance and the safe distance. The distance from the entry point to the medial wall breach site (breach distance) was measured on post-operative CT images. Results The mean critical distance was 9.3 ± 1.1 mm. The critical distance of vertebrae from different levels was relatively constant, between 8.1 and 10.1 mm. The mean safe distance was 15.2 ± 1.3 mm. The safe distance of vertebrae from different levels was also relatively constant, between 14.5 and 16 mm. The mean critical length was 5.9 ± 1.0 mm. The critical length of vertebrae between T3 and T12 was relatively constant, ranging from 5 to 6.5 mm. The mean breach distance was 12.3 ± 1.3 mm and the each breach always recognized between the critical distance and the safe distance. Conclusions The risk of pedicle medial wall perforation increases as the pedicle probe advances beyond the critical distance of 8-10 mm from the entry point, while it decreases entering into the safe distance at 14.5-16 mm. These parameters were relatively constant even in the most rotated vertebrae at T9 or those with the narrowest pedicle at T7 or T4. © Springer-Verlag 2011.

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Sterility of posterior elements of the spine in posterior correction surgery

Shiono Yuta, Watanabe Kota, Hosogane Naobumi, Tsuji Takashi, Ishii Ken, Nakamura Masaya, Toyama Yoshiaki, Chiba Kazuhiro, Matsumoto Morio

Spine 37 ( 6 ) 523 - 526 2012.03

ISSN 0362-2436

Study Design.: Prospective clinical series. Objective.: To investigate the sterility of the posterior elements of the spine during posterior correction surgery. Summary of Background Data.: Bacterial growth in the operating field is considered one of the causes of surgical-site infection. Methods.: A total of 80 consecutive patients (mean age = 19.5 years) who underwent posterior correction surgery for spinal deformities were included in the study. During surgery, specimens for bacterial culture were obtained by swabs from (1) the skin after cleansing using povidone-iodine scrub solution but before draping, (2) laminae immediately after exposure, (3) laminae immediately after screw placement, (4) laminae immediately before wound closure, (5) a small piece of bone obtained from the spinous process immediately after exposure and placed on a sterile dish during surgery as a control, kept covered, and (6) a similar sample as (5), kept uncovered. The culture was conducted on both blood agar and Gifu anaerobic medium agar plates. Results.: No patient developed surgical-site infection. The culture was positive in specimen (S) 1 in 25 patients (31.3%), S2 in 20 (25%), S3 in 25 (31.3%), S4 in 26 (32.5%), S5 in 6 (7.5%), and S6 in 7 (8.8%). Bacterial species included Propionibacterium acnes in 15 specimens, Propionibacterium species in 9, and others in 10. Of the 25 patients with a positive culture in S1 and 55 patients without, 22 (88%) and 26 (47.3%), respectively, demonstrated a positive culture in specimens obtained during surgery. Conclusion.: The culture was more frequently positive in specimens obtained immediately before wound closure than in those harvested immediately after exposure and isolated from the surgical field. The results suggest that bacterial contamination of the operating field may originate from the skin of the patient during surgery. © 2012 Lippincott Williams and Wilkins.

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Management of chronic atlantoaxial rotatory fixation

Ishii Ken, Toyama Yoshiaki, Nakamura Masaya, Chiba Kazuhiro, Matsumoto Morio

Spine 37 ( 5 ) 2012.03

ISSN 0362-2436

Study Design: Retrospective case series of chronic atlantoaxial rotatory fixation (AARF) treated by a novel closed reduction method (remodeling therapy) and review of the literature. Objective: To describe clinical features of chronic AARF and the rationale of the remodeling therapy. Summary of Background Data: Treatment strategy for chronic recurrent AARF remains controversial. Posterior C1-C2 arthrodesis has been widely used for recurrent unstable AARFs after the closed reduction, and a variety of posterior fusion techniques have been advocated. In contrast, several investigators reported a chronic AARF case treated by a simple traction or closed reduction followed by cervical immobilization. Previously, we have found that a deformity of the superior C2 facet joint (C2 facet deformity) on three dimensional computed tomography (3D CT) reconstructions is a risk factor for recurrent subluxation. In addition, the remodeling of this C2 facet deformity by careful closed manipulation followed by halo fixation (remodeling therapy) could prevent the recurrence of subluxation. Methods: Twelve children with chronic AARF who sustained torticollis for an average of 4.4 months after the onset were referred to our clinic. The mean age at the initial visit was 7.8 years. All patients underwent the remodeling therapy as reported previously. Radiographic findings and clinical courses were retrospectively reviewed. Treatment methodology, pearls, and pitfalls of the remodeling therapy were discussed with review of the literature. Results: 3D CT images before reduction revealed persistent atlantoaxial subluxation and the C2 facet deformity in the dislocated side in all cases. Follow-up 3D CT scans demonstrated the remodeling of the C2 facet deformity at an average of 2.4 months after successful reduction of subluxation. Neither recurrence of symptoms nor subluxation was observed at a mean follow-up of 42 months in any case. The cervical range of motion was 73.9° at the dislocated and 83.5° at the contra-dislocated side from the midline. Conclusion: Chronic irreducible and recurrent unstable AARF should be initially managed by remodeling therapy using the facet deformity sign as a clinical index, if the C1 and C2 have not been osseously fused. Copyright © 2012 Lippincott Williams & Wilkins.

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Surgical treatment of ossification of the posterior longitudinal ligament and its outcomes

Matsumoto Morio, Chiba Kazuhiro, Toyama Yoshiaki

Spine 37 ( 5 ) 2012.03

ISSN 0362-2436

Study Design: Review article. Objective: To discuss the history, indication, surgical outcomes, prognostic factors, and complications of laminoplasty for ossification of the posterior longitudinal ligament (OPLL) of the cervical spine. Summary of Background Data: OPLL usually requires surgery, which often involves indirect decompression by the posterior approach. Of the posterior procedures for OPLL, laminoplasty is the favored treatment. Here, we review the previously published literature on laminoplasty for OPLL. Methods: PubMed and previously published English and Japanese book chapters were searched for posterior procedures for treating OPLL. Results: There is a large body of literature on OPLL and its treatment. Based on a review of the literature, the history, indication, surgical outcomes, prognostic factors, and complications of laminoplasty for OPLL were examined. The results showed that long-term outcomes of both the open-door and double-door types of laminoplasty are favorable, although late neurological deterioration occurs in some patients. Preoperative kyphosis of the cervical spine and severe (>60%) compromise of the spinal canal by OPLL appear to be the limiting factors for the indication of laminoplasty. Complications of laminoplasty include segmental motor palsy, lamina closure, and axial symptoms. Conclusion: Laminoplasty is a feasible surgical option for OPLL if candidate patients are appropriately selected. Copyright © 2012 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.

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Establishment of a real-time, quantitative, and reproducible mouse model of staphylococcus osteomyelitis using bioluminescence imaging

Funao Haruki, Ishii Ken, Nagai Shigenori, Sasaki Aya, Hoshikawa Tomoyuki, Aizawa Mamoru, Okada Yasunori, Chiba Kazuhiro, Koyasu Shigeo, Toyama Yoshiaki, Matsumoto Morio

Infection and Immunity 80 ( 2 ) 733 - 741 2012.02

ISSN 0019-9567

Osteomyelitis remains a serious problem in the orthopedic field. There are only a few animal models in which the quantity and distribution of bacteria can be reproducibly traced. Here, we established a real-time quantitative mouse model of osteomyelitis using bioluminescence imaging (BLI) without sacrificing the animals. A bioluminescent strain of Staphylococcus aureus was inoculated into the femurs of mice. The bacterial photon intensity (PI) was then sequentially measured by BLI. Serological and histological analyses of the mice were performed. The mean PI peaked at 3 days, and stable signals were maintained for over 3 months after inoculation. The serum levels of interleukin-6, interleukin-1β, and C-reactive protein were significantly higher in the infected mice than in the control mice on day 7. The serum monocyte chemotactic protein 1 level was also significantly higher in the infected group at 12 h than in the control group. A significantly higher proportion of granulocytes was detected in the peripheral blood of the infected group after day 7. Additionally, both acute and chronic histological manifestations were observed in the infected group. This model is useful for elucidating the pathophysiology of both acute and chronic osteomyelitis and to assess the effects of novel antibiotics or antibacterial implants. © 2012, American Society for Microbiology.

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Spontaneous regression of soft disc herniation in patients with cervical myelopathy

Matsumoto Morio, Okada Eijiro, Watanabe Kota, Hosogane Naobumi, Tsuji Takashi, Ishii Ken, Nakamura Masaya, Chiba Kazuhiro, Toyama Yoshiaki

Neurosurgery Quarterly 22 ( 1 ) 7 - 11 2012.02

ISSN 1050-6438

PURPOSE:: To describe patients with cervical myelopathy due to cervical disc herniation (CDH) who showed spontaneous regression, we conducted a retrospective study. METHODS:: A review of clinical records since 1990 identified 19 patients (12 male and 7 female; mean age, 42.4 y) with mild cervical myelopathy due to CDH who exhibited spontaneous CDH regression after conservative treatment. RESULTS:: The mean Japanese Orthopaedic Association scores were 13.7±1.4 before conservative treatment, 14.8±1.2 at 3 months, and 15.9±0.7 at final follow-up. On magnetic resonance imaging (MRI), the CDH regression was observed at 7.5 months on average. Intramedullary high-signal intensity was observed in 15 patients (78.9%) before treatment and 9 patients (47.4%) at follow-up. The mean area of the spinal cord was 58.4±8.3 mm before treatment and 62.4±9.7 mm at follow-up. CONCLUSIONS:: Spontaneous regression of the CDH in 19 patients with mild cervical myelopathy was observed, with improvements in neurological status and in intramedullary high-signal intensity on MRI. © 2012 by Lippincott Williams & Wilkins.

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Changes in the cross-sectional area of deep posterior extensor muscles of the cervical spine after anterior decompression and fusion

Matsumoto Morio, Okada Eijiro, Ichihara Daisuke, Watanabe Kota, Chiba Kazuhiro, Toyama Yoshiaki, Fujiwara Hirokazu, Momoshima Suketaka, Nishiwaki Yuji, Hashimoto Takeshi, Iwanami Akio, Ikegami Takeshi, Takahata Takeshi

European Spine Journal 21 ( 2 ) 304 - 308 2012.02

ISSN 0940-6719

Purpose To evaluate changes in the transverse area of deep posterior muscles of the cervical spine 10 years after anterior cervical decompression and fusion (ACDF), in comparison with healthy volunteers. Methods Thirty-one patients (22 males, 9 females, mean age at follow-up 59.3 years, mean follow-up 12.1 years) who had undergone preoperativeMRI and non-instrumented ACDF within levels C3-4 to C5-6 were enrolled. 32 asymptomatic volunteers (17 males, 15 females; mean age, 54.7 years; mean follow-up, 11.7 years) who underwent MRI between 1993 and 1996 served as controls. Follow-up MRI was performed on both patients and control subjects, and the cross-sectional areas of deep posterior muscles were measured digitally at levels C3-4, 4-5, and 5-6. Results The mean total cross-sectional area in the ACDF and control groups was 4,693.6 ± 1,140.9 and 4,825.8 ± 1,048.2 mm ² in the first MR study (P = 0.63), and 4,616.7 ± 1,086.0 and 5,036.7 ± 1,105.6 mm ² at followup (P = 0.13). The total cross-sectional area in the ACDF group slightly decreased, while that in the control group increased (-77.1 ± 889.7 vs. 210.9 ± 622.0 mm ², P = 0.14). The mean change in the cross-sectional area had no significant correlation with clinical symptoms, including neck pain or JOA score. Conclusions ACDF patients did not show a marked decrease in the cross-sectional area of the deep posterior cervical muscles, but as compared with control subjects there was a slight decrease. A decrease in the cross-sectional area of these muscles after ACDF may not result in the axial symptoms as seen in patients treated by posterior surgery. © 2011 Springer-Verlag.

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Vertebral derotation in adolescent idiopathic scoliosis causes hypokyphosis of the thoracic spine

Watanabe Kota, Nakamura Takayuki, Iwanami Akio, Hosogane Naobumi, Tsuji Takashi, Ishii Ken, Nakamura Masaya, Toyama Yoshiaki, Chiba Kazuhiro, Matsumoto Morio

BMC Musculoskeletal Disorders 13 2012

Background: The purpose of this study was to test the hypothesis that direct vertebral derotation by pedicle screws (PS) causes hypokyphosis of the thoracic spine in adolescent idiopathic scoliosis (AIS) patients, using computer simulation. Methods: Twenty AIS patients with Lenke type 1 or 2 who underwent posterior correction surgeries using PS were included in this study. Simulated corrections of each patients scoliosis, as determined by the preoperative CT scan data, were performed on segmented 3D models of the whole spine. Two types of simulated extreme correction were performed: 1) complete coronal correction only (C method) and 2) complete coronal correction with complete derotation of vertebral bodies (C + D method). The kyphosis angle (T5-T12) and vertebral rotation angle at the apex were measured before and after the simulated corrections. Results: The mean kyphosis angle after the C + D method was significantly smaller than that after the C method (2.7 ± 10.0° vs. 15.0 ± 7.1°, p<0.01). The mean preoperative apical rotation angle of 15.2 ± 5.5° was completely corrected after the C + D method (0°) and was unchanged after the C method (17.6 ± 4.2°). Conclusions: In the 3D simulation study, kyphosis was reduced after complete correction of the coronal and rotational deformity, but it was maintained after the coronal-only correction. These results proved the hypothesis that the vertebral derotation obtained by PS causes hypokyphosis of the thoracic spine. © 2012 Watanabe et al. licensee BioMed Central Ltd.

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Dual functions of cell-autonomous and non-cell-autonomous ADAM10 activity in granulopoiesis

Yoda Masaki, Kimura Tokuhiro, Tohmonda Takahide, Uchikawa Shinichi, Koba Takeshi, Takito Jiro, Morioka Hideo, Matsumoto Morio, Link Daniel C., Chiba Kazuhiro, Okada Yasunori, Toyama Yoshiaki, Horiuchi Keisuke

Blood 118 ( 26 ) 6939 - 6942 2011.12

ISSN 0006-4971

Previous studies have revealed various extrinsic stimuli and factors involved in the regulation of hematopoiesis. Among these, Notch-mediated signaling has been suggested to be critically involved in this process. Herein, we show that conditional inactivation of ADAM10, a membrane-bound protease with a crucial role in Notch signaling (S2 cleavage), results in myeloproliferative disorder (MPD) highlighted by severe splenomegaly and increased populations of myeloid cells and hematopoietic stem cells. Reciprocal transfer of bone marrow cells between wild-type and ADAM10 mutant mice revealed that ADAM10 activity in both hematopoietic and nonhematopoietic cells is involved in the development of MPD. Notably, we found that MPD caused by lack of ADAM10 in nonhematopoietic cells was mediated by G-CSF, whereas MPD caused by ADAM10-deficient hematopoietic cells was not. Taken together, the present findings reveal previously undescribed nonredundant roles of cell-autonomous and non-cell-autonomous ADAM10 activity in the maintenance of hematopoiesis. © 2011 by The American Society of Hematology.

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A genome-wide association study identifies common variants near LBX1 associated with adolescent idiopathic scoliosis

Takahashi Yohei, Kou Ikuyo, Takahashi Atsushi, Johnson Todd A., Kono Katsuki, Kawakami Noriaki, Uno Koki, Ito Manabu, Minami Shohei, Yanagida Haruhisa, Taneichi Hiroshi, Tsuji Taichi, Suzuki Teppei, Sudo Hideki, Kotani Toshiaki, Watanabe Kota, Chiba Kazuhiro, Hosono Naoya, Kamatani Naoyuki, Tsunoda Tatsuhiko, Toyama Yoshiaki, Kubo Michiaki, Matsumoto Morio, Ikegawa Shiro

Nature Genetics 43 ( 12 ) 1237 - 1240 2011.12

ISSN 1061-4036

Adolescent idiopathic scoliosis is a pediatric spinal deformity affecting 2-3% of school-age children worldwide. Genetic factors have been implicated in its etiology. Through a genome-wide association study (GWAS) and replication study involving a total of 1,376 Japanese females with adolescent idiopathic scoliosis and 11,297 female controls, we identified a locus at chromosome 10q24.31 associated with adolescent idiopathic scoliosis susceptibility. The most significant SNP (rs11190870; combined P = 1.24 × 10 ^-19; odds ratio (OR) = 1.56) is located near LBX1 (encoding ladybird homeobox 1). The identification of this susceptibility locus provides new insights into the pathogenesis of adolescent idiopathic scoliosis. © 2011 Nature America, Inc. All rights reserved.

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Matrix metalloproteinase 13 in the ligamentum flavum from lumbar spinal canal stenosis patients with and without diabetes mellitus

Cui Guanyu, Watanabe Kota, Miyauchi Yoshiteru, Hosogane Naobumi, Tsuji Takashi, Ishii Ken, Nakamura Masaya, Toyama Yoshiaki, Chiba Kazuhiro, Miyamoto Takeshi, Matsumoto Morio

Journal of Orthopaedic Science 16 ( 6 ) 785 - 790 2011.11

ISSN 0949-2658

Background: Lumbar spinal canal stenosis (LSCS) is one of the most common spinal disorders in the elderly, and ligamentum flavum (LF) hypertrophy is an important cause of LSCS. Matrix metalloproteinase 13 (MMP13) can degrade fibrillar collagens and elastic microfibrils, and is involved in inflammation and fibrosis. The purpose of this study was to compare the expression of MMP13 in the LF from LSCS patients with diabetes mellitus [DM (+)] with that in the LF from patients without DM [DM (-)] and to analyze the relationship among DM, MMP13 expression, and LF hypertrophy. Methods: LFs from 11 DM (+) and 24 DM (-) LSCS patients were analyzed in this study. Histology analysis using hematoxylin and eosin and Masson's trichrome stain was performed for each LF. The expression of MMP13 was analyzed by quantitative real-time PCR. The thickness of LF was measured by CT. Results: In the LF from DM (+) LSCS patients, the elastic fibers were more disorganized and had lower volumes than in the LF from DM (-) LSCS patients, while more fibrotic tissue was observed in the LF from DM (+) than from DM (-) LSCS patients. MMP13 expression was significantly higher in the LF from DM (+) LSCS patients (0.46 ± 0.61 vs. 0.05 ± 0.09, P = 0.002). The LF from the DM (+) LSCS patients was significantly thicker than that from the DM (-) LSCS patients (5.0 ± 0.9 vs. 3.1 ± 0.8 mm, P < 0.01), and the thickness was correlated with the expression of MMP13 (correlation coefficient = 0.43, P = 0.01, Pearson's correlation test). Conclusion: DM-related MMP13 expression can be one of the factors contributing to fibrosis and hypertrophy of the LF. Further research on the mechanism of this process may lead to new therapies for LF hypertrophy. © 2011 The Japanese Orthopaedic Association.

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Mechanism of osteoporosis in adolescent idiopathic scoliosis

Kono Hitoshi, MacHida Masafumi, Saito Masashi, Nishiwaki Yuji, Kato Hiroyuki, Hosogane Naobumi, Chiba Kazuhiro, Miyamoto Takeshi, Matsumoto Morio, Toyama Yoshiaki

Journal of Pineal Research 51 ( 4 ) 387 - 393 2011.11

ISSN 0742-3098

To clarify the mechanism of osteoporosis in adolescent idiopathic scoliosis (AIS), we investigated radiological and histological changes in the cervical vertebrae of a chicken thoracic scoliosis model. Forty newly hatched broiler chicks were randomly divided into four equal groups: sham-operated chickens serving as control (CON), pinealectomized chickens (PNX), sham-operated (CON + MLT) and pinealectomized chickens (PNX + MLT) that received intraperitoneal administration of melatonin. Pinealectomy was performed at the age of 3 days, and the chickens were killed at 2 months of age. Postmortem X-rays were examined for the presence of scoliosis, and micro-computed tomography (micro-CT) images were taken to evaluate the microstructure of the cervical vertebrae. Histological specimens of the scanned cervical vertebra were prepared, and a midsagittal section was stained with hematoxylin and eosin and tartrate-resistant acid phosphatase to evaluate the numbers of osteoblasts and osteoclasts, respectively. Scoliosis developed at the thoracic spine in all chickens of the PNX and in two of the PNX + MLT group. Micro-CT data revealed that chickens in the PNX group had a greater degree of generalized osteoporosis compared with the other birds. The number of osteoblasts was significantly decreased in the PNX group, while no significant difference was observed among chickens in the numbers of osteoclasts. Our results suggest that melatonin deficiency reduces osteoblast proliferation and leads to the development of scoliosis and osteoporosis. The restoration of melatonin prevented the development of scoliosis and osteoporosis, indicating that melatonin levels may be crucial to the development of deformity and osteoporosis in AIS. © 2011 John Wiley & Sons A/S.

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Outcomes of fusion surgery for ossification of the posterior longitudinal ligament of the thoracic spine

Matsumoto Morio, Toyama Yoshiaki, Chikuda Hirotaka, Takeshita Katsushi, Kato Tsuyoshi, Shindo Shigeo, Abumi Kuniyoshi, Takahata Masahiko, Nohara Yutaka, Taneichi Hiroshi, Tomita Katsuro, Kawahara Norio, Imagama Shiro, Matsuyama Yukihiro, Yamazaki Masashi, Okawa Akihiko

Journal of Neurosurgery: Spine 15 ( 4 ) 380 - 385 2011.10

ISSN 1547-5654

Object. The aim of this study was to evaluate the outcomes of fusion surgery in patients with ossification of the posterior longitudinal ligament in the thoracic spine (T-OPLL) and to identify factors significantly related to surgical outcomes. Methods. The study included 76 patients (34 men and 42 women with a mean age of 56.3 years) who underwent fusion surgery for T-OPLL at 7 spine centers during the 5-year period from 2003 to 2007. The authors evaluated the patient demographic data, underlying disease, preoperative comorbidities, history of spinal surgery, radiological findings, surgical methods, surgical outcomes, and complications. Surgical outcomes were assessed using the Japanese Orthopaedic Association (JOA) scale score for thoracic myelopathy (11 points) and the recovery rate. Results. The mean JOA scale score was 4.6 ± 2.1 points preoperatively and 7.7 ± 2.5 points at the time of the final follow-up examination, yielding a mean recovery rate of 45.4% ± 39.1%. The recovery rates by surgical method were 38.5% ± 37.8% for posterior decompression and fusion, 65.0% ± 35.6% for anterior decompression and fusion via an anterior approach, 28.8% ± 41.2% for anterior decompression via a posterior approach, and 57.5% ± 41.1% for circumferential decompression and fusion. The recovery rate was significantly higher in patients without diabetes mellitus (DM) than in those with DM. One or more complications were experienced by 31 patients (40.8%), including 20 patients with postoperative neurological deterioration, 7 with dural tears, 5 with epidural hematomas, 4 with respiratory complications, and 10 with other complications. Conclusions. The outcomes of fusion surgery for T-OPLL were favorable. The absence of DM correlated with better outcomes. However, a high rate of complications was associated with the fusion surgery.

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Cross-sectional area of posterior extensor muscles of the cervical spine in asymptomatic subjects

Okada Eijiro, Matsumoto Morio, Ichihara Daisuke, Chiba Kazuhiro, Toyama Yoshiaki, Fujiwara Hirokazu, Momoshima Suketaka, Nishiwaki Yuji, Takahata Takeshi

European Spine Journal 20 ( 9 ) 1567 - 1573 2011.09

ISSN 0940-6719

There has been no prospective study on agerelated changes of the extensor muscles of the cervical spine in healthy subjects. This study was conducted to elucidate any association between the changes in cross-sectional area of the extensor muscles of the cervical spine on MRIs and cervical disc degeneration or the development of clinical symptoms. Sixty-two subjects who underwent MR imaging by a 1.5-Tesla machine between 1993 and 1996 as asymptomatic volunteers in a previous study were recruited again 10 years later for this follow-up study. The mean interval between the studies was 11.0 ± 0.7 years. The cross-sectional areas of the multifidus, semispinalis cervicis, semispinalis capitis, and splenius capitis at C3-C4, C4-C5, and C5-C6 intervertebral levels were measured on T2-weighted axial images using Image J 1.42. The mean cross-sectional areas of the deep extensor muscles were 1,396.8 ± 337.6 mm ² at the C3-C4 level, 1,514.7 ± 381.0 mm ² at the C4-C5 level, and 1,542.8 ± 373.5 mm2 at the C5-C6 level in the previous investigation. The cross-sectional areas were 1,498.7 ± 374.4 mm2 at the C3-C4 level, 1,569.9 ± 390.9 mm ² at the C4-C5 level, and 1,599.6 ± 364.3 mm ² at the 10-year follow-up. An increase in the cross-sectional area of the muscles was more frequently observed in subjects in their tens to thirties in the initial study, while a decrease was more frequently observed in those in their forties and older in the initial study. Disc degeneration was not correlated with a change in extensor muscle volume. Development of shoulder stiffness during follow-up was significantly negatively correlated with a change in the cross-sectional area of the deep extensor muscles. © Springer-Verlag 2011.

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Late instrumentation failure after total en bloc spondylectomy

Matsumoto Morio, Watanabe Kota, Tsuji Takashi, Ishii Ken, Nakamura Masaya, Chiba Kazuhiro, Toyama Yoshiaki

Journal of Neurosurgery: Spine 15 ( 3 ) 320 - 327 2011.09

ISSN 1547-5654

Object. The object of this study was to investigate failures after spinal reconstruction following total en bloc spondylectomy (TES), related factors, and sequelae arising from such failures in patients with malignant spinal tumors. Methods. Fifteen patients (12 males and 3 females, with a mean age of 46.5 years) with malignant spinal tumors who underwent TES and survived for more than 1 year were included in this analysis (mean follow-up 41.5 months). Seven patients had primary tumors, including giant cell tumors in 4 patients, chordoma in 2, and Ewing sarcoma in 1. Eight patients had metastatic tumors, including thyroid cancer in 6 and renal cell cancer and malignant fibrous histiocytoma in 1 patient each. Seven patients without prominent paravertebral extension of the tumor were treated using a posterior approach alone, and 8 patients who exhibited prominent anterior or anterolateral extension of the tumors into the thoracic or abdominal cavity were treated using a combined anterior and posterior approach. Spinal reconstruction after tumor resection was performed using a combination of anterior structural support and posterior instrumentation. The relationship between instrumentation failure and clinical and radiographic factors, including age, sex, history of previous surgery, preoperative radiotherapy, tumor histology, tumor level, surgical approach, number of resected vertebrae, rod diameter, number of instrumented vertebrae, and cage subsidence, was investigated. Results. Six patients (40%) with spinal instrumentation failure were identified: rod breakage occurred in 3 patients, and breakage of both the rod and the cage, combined cage breakage and screw back-out, and endplate fracture arising from cage subsidence occurred in 1 patient each. All of these patients experienced acute or chronic back pain, but only 1 patient with a tumor recurrence experienced neurological deterioration upon instrumentation failure. Cage subsidence (≥ 5 mm), preoperative irradiation, and the number of instrumented vertebrae (≤ 4 vertebrae) were significantly related to late instrumentation failure. Conclusions. Late instrumentation failure was a frequent complication after TES. Although patients with instrumentation failure experienced back pain, the neurological sequelae were not catastrophic. For prevention, meticulous preparation of the graft site and a longer posterior fixation should be considered.

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Neurological complications of cervical laminoplasty for patients with ossification of the posterior longitudinal ligament - A multi-institutional retrospective study

Seichi Atsushi, Hoshino Yuichi, Kimura Atsushi, Nakahara Shinnosuke, Watanabe Masahiko, Kato Tsuyoshi, Ono Atsushi, Kotani Yoshihisa, Mitsukawa Mamoru, Ijiri Kosei, Kawahara Norio, Inami Satoshi, Chikuda Hirotaka, Takeshita Katsushi, Nakagawa Yukihiro, Taguchi Toshihiko, Yamazaki Masashi, Endo Kenji, Sakaura Hironobu, Uchida Kenzo, Kawaguchi Yoshiharu, Neo Masashi, Takahashi Masahito, Harimaya Katsumi, Hosoe Hideo, Imagama Shiro, Taniguchi Shinichiro, Ito Takui, Kaito Takashi, Chiba Kazuhiro, Matsumoto Morio, Toyama Yoshiaki

Spine 36 ( 15 ) 2011.07

ISSN 0362-2436

STUDY DESIGN.: Retrospective multi-institutional study. OBJECTIVE.: To investigate the incidence of neurological deficits after cervical laminoplasty for ossification of the posterior longitudinal ligament (OPLL). SUMMARY OF BACKGROUND DATA.: According to analysis of long-term results, laminoplasty for cervical OPLL has been reported as a safe and effective alternative procedure with few complications. However, perioperative neurological complication rates of laminoplasty for cervical OPLL have not been well described. METHODS.: Subjects comprised 581 patients (458 men and 123 women; mean age: 62 ± 10 years; range: 30-86 years) who had undergone laminoplasty for cervical OPLL at 27 institutions between 2005 and 2008. Continuous-type OPLL was seen in 114, segmental-type in 146, mixed-type in 265, local-type in 24, and not judged in 32 patients. Postoperative neurological complications within 2 weeks after laminoplasty were analyzed in detail. Cobb angle between C2 and C7 (C2/C7 angle), maximal thickness, and occupying rate of OPLL were investigated. Pre- and postoperative magnetic resonance imaging was performed on patients with postoperative neurological complications. RESULTS.: Open-door laminoplasty was conducted in 237, double-door laminoplasty in 311, and other types of laminoplasty in 33 patients. Deterioration of lower-extremity function occurred after laminoplasty in 18 patients (3.1%). Causes of deterioration were epidural hematoma in 3, spinal cord herniation through injured dura mater in 1, incomplete laminoplasty due to vertebral artery injury while making a trough in 1, and unidentified in 13 patients. Prevalence of unsatisfactory recovery not reaching preoperative level by 6-month follow-up was 7/581 (1.2%). Mean occupying rate of OPLL for patients with deteriorated lower-extremity function was 51.2 ± 13.6% (range, 21.0%-73.3%), significantly higher than the 42.3 ± 13.0% for patients without deterioration. OPLL thickness was also higher in patients with deterioration (mean, 6.6 ± 2.2 mm) than in those without deterioration (mean, 5.7 ± 2.0 mm). No significant difference in C2/C7 lordotic angle was seen between groups. CONCLUSION.: Although most neurological deterioration can be expected to recover to some extent, the frequency of short-term neurological complications was higher than the authors expected. Copyright © 2011 Lippincott Williams & Wilkins.

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Long-term surgical outcomes of idiopathic spinal cord herniation

Nakamura Masaya, Fujiyoshi Kanehiro, Tsuji Osahiko, Watanabe Kota, Tsuji Takashi, Ishii Ken, Matsumoto Morio, Toyama Yoshiaki, Chiba Kazuhiro

Journal of Orthopaedic Science 16 ( 4 ) 347 - 351 2011.07

ISSN 0949-2658

Background: Because of the lack of long-term postoperative follow-up studies of idiopathic spinal cord herniation (ISCH), there is little information about the long-term effectiveness and complications of the dural defect enlargement in patients with ISCH. The purpose of this study is to determine the long-term effectiveness of this procedure. Methods: Sixteen patients with ISCH were treated surgically by enlargement of the dural defect. The patient's neurological status and surgical outcome were evaluated by the JOA scores for thoracic myelopathy and the recovery rate (mean follow-up period 9.6 years). Correlations between the surgical outcomes and patients' age and duration of disease were assessed retrospectively. The patients were also divided into two groups based on the location of the dural defect: the ventro-lateral (VL) group and the ventral (V) group. The difference in the duration of disease, preoperative JOA score, and the recovery rate were compared between the two groups. Results: There was no recurrence of ISCH after surgery. The mean recovery rate was 42.6%. There was a significant correlation between the patient's age and the recovery rate, and between the duration of disease and the recovery rate. The median recovery rate was significantly lower in the V group than in the VL group. There were no complications related to CSF leakage after surgery. Conclusions: Long-term surgical outcomes of enlargement of the dural defect for ISCH were stable and favorable without recurrences or any complications. This procedure should be considered for patients with ISCH before their neurological deficit worsens, especially for the patients in whom the dural defect is located at the ventral part of the dural canal. © 2011 The Author(s).

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Lack of association between adolescent idiopathic scoliosis and previously reported single nucleotide polymorphisms in MATN1, MTNR1B, TPH1, and IGF1 in a Japanese population

Takahashi Yohei, Matsumoto Morio, Karasugi Tatsuki, Watanabe Kota, Chiba Kazuhiro, Kawakami Noriaki, Tsuji Taichi, Uno Koki, Suzuki Teppei, Ito Manabu, Sudo Hideki, Minami Shohei, Kotani Toshiaki, Kono Katsuki, Yanagida Haruhisa, Taneichi Hiroshi, Takahashi Atsushi, Toyama Yoshiaki, Ikegawa Shiro

Journal of Orthopaedic Research 29 ( 7 ) 1055 - 1058 2011.07

ISSN 0736-0266

Adolescent idiopathic scoliosis (AIS) is a spinal deformity most commonly arising in apparently healthy girls around puberty. AIS has a strong genetic predisposition. Several genetic associations between AIS and single nucleotide polymorphisms (SNPs) have been reported; common SNPs in the genes for matrilin 1 (MATN1), melatonin receptor 1B (MTNR1B), tryptophan hydroxylase 1 (TPH1), and insulin-like growth factor 1 (IGF1) are reported to be associated with AIS in Chinese. However, these associations have not been replicated so far. To confirm the associations, we compared these SNPs with AIS predisposition and curve severity in a population of Japanese females consisting of 798 AIS patients and 1,239 controls. All the subjects were genotyped using the PCR-based Invader assay. We found no association of any of the SNPs with AIS predisposition or curve severity. Considering the statistical power and sample size of the present study, we concluded that these SNPs are not associated with either AIS predisposition or curve severity in Japanese. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc.

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Replication study of the association between adolescent idiopathic scoliosis and two estrogen receptor genes

Journal of Orthopaedic Research 29 ( 6 ) 834 - 837 2011.06

ISSN 0736-0266

Adolescent idiopathic scoliosis (AIS) is a common disorder with a strong genetic predisposition. Associations between AIS and common single nucleotide polymorphisms (SNPs) in estrogen receptor genes have been reported. rs9340799 in the gene for estrogen receptor α (ESR1) is reported to be associated with curve severity in Japanese and with AIS predisposition and curve severity in Chinese. In addition, rs1256120 in the gene for estrogen receptor β (ESR2) is reported to be associated with AIS predisposition and curve severity in Chinese. However, the sample sizes of these previous studies were small, and the associations of these SNPs have not been replicated. To examine the association between AIS and estrogen receptor genes, we investigated the association of rs9340799 and rs1256120 with AIS predisposition and curve severity using a large Japanese population, consisting of 798 AIS patients and 637 sex-matched controls. We found no association of either SNP with AIS predisposition or curve severity in the Japanese population. Considering the statistical power of the present study and the limitations of the previous reports, we conclude that the associations of rs9340799 and rs1256120 with AIS predisposition and curve severity are negative. © 2010 Orthopaedic Research Society Published by Wiley Periodicals, Inc.

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