Akira Matsumura

Osaka City General Hospital, Ōsaka, Ōsaka, Japan

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Publications (15)27.83 Total impact

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    ABSTRACT: PURPOSE: Primary intraspinal facet cysts in the lumbar spine are uncommon, but it is unclear whether cyst incidence increases following decompression surgery and if these cysts negatively impact clinical outcome. We examined the prevalence, clinical characteristics, and the risk factors associated with intraspinal facet cysts after microsurgical bilateral decompression via a unilateral approach (MBDU). METHODS: We studied 230 patients treated using MBDU for lumbar degenerative disease (133 men and 97 women; mean age 70.3 years). Clinical status, as assessed by the Japanese Orthopedic Association (JOA) score and findings on X-ray and magnetic resonance images, was evaluated prior to surgery and at both 3 months and 1 year after surgery. The prevalence of intraspinal facet cysts was determined and preoperative risk factors were defined by comparing presurgical findings with clinical outcomes. RESULTS: Thirty-eight patients (16.5 %) developed intraspinal facet cysts within 1 year postoperatively, and 24 exhibited cysts within 3 months. In 10 patients, the cysts resolved spontaneously 1 year postoperatively. In total, 28 patients (12.2 %) had facet cysts 1 year postoperatively. The mean JOA score of patients with cysts 1 year postoperatively was significantly lower than that of patients without cysts. This poor clinical outcome resulted from low back pain that was not improved by conservative treatment. Most cases with spontaneous cyst disappearance were symptom-free 1 year later. The preoperative risk factors for postoperative intraspinal facet cyst formation were instability (OR 2.47, P = 0.26), scoliotic disc wedging (OR 2.23, P = 0.048), and sagittal imbalance (OR 2.22, P = 0.045). CONCLUSIONS: Postoperative intraspinal facet cyst formation is a common cause of poor clinical outcome in patients treated using MBDU.
    European Spine Journal 04/2013; · 2.47 Impact Factor
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    ABSTRACT: Object Minimally invasive decompressive surgery using a microscope or endoscope has been widely performed for the treatment of lumbar spinal canal stenosis (LSS). In this study the authors aimed to assess outcomes following microscopic bilateral decompression via a unilateral approach (MBDU) in terms of postoperative bone regrowth and preservation of the facet joints in patients with degenerative lumbar spondylolisthesis (DS) as compared with those in patients with LSS. Methods In the period from May 1998 to February 2007 at the authors' institution, 85 patients underwent MBDU at L4-5. Clinical outcome was evaluated before surgery and at the final follow-up using the Japanese Orthopaedic Association (JOA) score for low-back pain. The following radiographic parameters were assessed at the L4-5 segment before surgery and at the final follow-up: 1) percentage slip on standing lateral radiographs, 2) percentage slip on dynamic radiographs, 3) disc arc on dynamic radiographs, and 4) percentage of facet joint preservation on CT. Bone regrowth on the ventral and dorsal sides of the facet joint on CT were assessed at the final follow-up. Results The cases of 47 patients (23 with DS at L-4 and 24 with LSS at L4-5 without instability) who had a follow-up of at least 2 years were retrospectively reviewed. The improvement ratio in the JOA score, that is, the percentage improvement as indicated by the difference between preoperative and postoperative JOA scores, was not significantly different between patients with DS and LSS. The percentage slip had progressed at the latest follow-up in both groups (1.4% and 1.1%, respectively), and there was no significant difference between the 2 groups. The percentage of facet joint preservation in the DS and LSS groups was 72.8% and 83.4%, respectively, on the approach side and 95.5% and 96.5% on the contralateral side. Facet joint preservation was significantly less on the approach side than on the contralateral side in both groups. The average amount of bone regrowth on the dorsal and ventral sides of the facet joint was 3.4 and 0.9 mm, respectively, in the DS group and 2.0 and 1.0 mm in the LSS group. The difference between the 2 groups was not significant. Facet joint preservation and bone regrowth were not correlated with clinical outcomes. Conclusions Microscopic bilateral decompression via a unilateral approach can prevent postoperative spinal instability because of good preservation of the posterior elements including the facet joints, which is thought to be the main reason for the relatively small amount of bone regrowth after surgery.
    Journal of neurosurgery. Spine 03/2013; · 1.61 Impact Factor
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    ABSTRACT: Study Design. Prospective multicenter studyObjective. To examine whether initial conservative treatment interventions for osteoporotic vertebral fractures (OVF) influence patient outcomes.Summary of Background Data. OVFs have been described as stable spinal injuries and, in most cases, are managed well with conservative treatment. However, Systematic treatments for OVF have not been clearly established.Methods. A total of 362 OVF patients (59 men and 303 women; mean age, 76.3 years) from 25 institutes were enrolled in this clinical study. All of the patients were treated conservatively without any surgical interventions. The patient outcomes were evaluated 6 months after the fractures on the basis of Short Form-36 (SF-36) Physical Component Summary (PCS) and Mental Component Summary (MCS), activities of daily living (ADL; the Japanese long-term care insurance system), back pain (visual analog scale; VAS), cognitive status (Mini-Mental State Examination), and vertebral collapse, which were used as response variables. Furthermore, brace type, hospitalization, bisphosphonates after injury, and painkillers after injury were explanatory variables for the treatment interventions. To evaluate the independent effects of treatment interventions on patient outcomes, we performed multivariate logistic regression analyses and obtained odds ratios that were adjusted for the potential confounding effects of age, sex, level of fracture, presence of middle column injury, pain VAS at enrollment, MMSE score at enrollment , and previous use of steroids.Results. There was no significant difference for treatment intervention factors including brace type, hospitalization, bisphosphonates after injury, and painkillers after injury. For adjusting factors, the presence of middle column injury was significantly associated with SF-36 PCS ≤ 40, reduced ADL, prolonged back pain, and vertebral collapse. Female sex and advanced age were associated with SF-36 PCS ≤ 40. Low MMSE scores at enrollment was associated with SF-36 PCS ≤ 40 and reduced ADL. The previous use of steroids was associated with SF-36 MCS ≤ 40, prolonged back pain, and vertebral collapse. No other examined variables were significant risk factors for patient outcomes.Conclusion. These results showed that treatment intervention factors did not affect patient outcomes 6 months after OVF. Middle column injury was a significant risk factor for both clinical and radiological outcomes. In the future, establishing systematic treatments for cases with middle column injuries is needed.
    Spine 02/2013; · 2.16 Impact Factor
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    ABSTRACT: The purpose of radiation therapy (RT) for patients with spinal metastases is pain relief and control of paralysis. The aim of the present study was to assess pain relief using RT and to evaluate prognostic factors for pain control. We evaluated 97 consecutive patients, of mean age 62.7 years (range 28 to 86), with spinal metastases that had been treated by RT. We evaluated the effects of RT using pain level assessed using a drug grading scale based on the World Health Organization standards. The following potential prognostic factors for pain control of RT were evaluated using multivariate logistic regression analysis: age, gender, tumor type, performance status (PS), number of spinal metastases, and a history of chemotherapy. Among the 97 patients who underwent RT for pain relief, 68 patients (70.1%) presented with pain reduction. PS (odds ratio: 1.931; 95% confidence interval: 1.244 to 2.980) was revealed by multivariate logistic regression analysis to be the most important prognostic factor for pain control using RT. In conclusion, we found that RT was more effective for patients with spinal metastases while they maintained their PS.
    Global spine journal. 09/2012; 2(3):137-42.
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    ABSTRACT: STUDY DESIGN:: A cross-sectional study. OBJECTIVE:: To evaluate the segmental instability of wedging segments using dynamic films and the impact of osteophyte formation on segmental motion in degenerative lumbar scoliosis (DLS). SUMMARY OF BACKGROUND DATA:: Evaluation of segmental instability in DLS is essential for spinal surgery to make the decision "fusion or not fusion." Some previous studies have shown radiographic data regarding segmental instability in DLS. However, little is known about segmental motion of wedging segments in DLS. METHODS:: A total of 101 patients complaining of neurogenic claudication owing to lumbar spinal canal stenosis (LCS) were enrolled and divided into 2 groups based on their coronal spinal deformity; Cobb angle of >10 degree (DLS group) or <10 degree (LCS group). The following parameters were measured on anteroposterior films: lateral translation, degree of osteophyte formation, and range of motion (ROM) in lateral bending films. The facet joint space discrepancy was measured on computed tomography images. The radiographic parameters were compared between 85 wedging segments (>5 degrees) in DLS group and 150 nonwedging segments in LCS group. RESULTS:: Mean lateral translation was significantly greater in the DLS group (P<0.01 for each level). Average joint space discrepancy was significantly greater in the DLS group (P<0.01 at L2/3 and L3/4, P =0.01 at L4/5). ROM was significantly greater in the DLS group with the same degree osteophyte formation. Degree of osteophyte formation was inversely correlated with ROM in the DLS group (R=0.5696). CONCLUSIONS:: The present study indicated that wedging segments in DLS had greater motion than nonwedging segments in LCS. However, the osteophyte formation provided restabilization for the wedging segments in DLS, suggesting that evaluation of osteophyte formation is an important factor in surgical decision making for DLS.
    Journal of spinal disorders & techniques 02/2012; · 1.21 Impact Factor
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    ABSTRACT: A prospective observational study. To evaluate the paravertebral muscle (PVM) degeneration in patients with degenerative lumbar scoliosis (DLS), using magnetic resonance imaging. Several studies have described the histological and morphological changes to the PVM in patients with chronic low back pain and lumbar radiculopathy. However, there is little knowledge about the PVM changes in patients with DLS. Fifty-seven patients with lumbar spinal stenosis (LSS) with DLS (DLS group) and 50 control patients with LSS without DLS (LSS group) were examined. The cross-sectional area (CSA) and percentage of fat infiltration area (%FIA) of the bilateral multifidus and longissimus muscles at the L1-S1 levels were measured using T2-weighted axial magnetic resonance imaging and computer software. A multifidus muscle biopsy and histological evaluation were performed in some patients. In the DLS group, the CSA of the multifidus muscle was significantly smaller and the %FIA of both muscles was significantly higher on the concave side than on the convex side at all levels (P < 0.0001 for each). These differences were also found in the longissimus muscles at the L4-L5 and L5-S1 levels (P < 0.0001 for each). Histologically, the multifidus muscle exhibited reductions in the muscle fiber size and number of nuclei on the concave side. In the LSS group, the total CSA and %FIA did not differ significantly between the left and right sides. However, in patients with unilateral radiculopathy, the CSA of the multifidus muscle was significantly smaller (P < 0.05) and the %FIA of both muscles was significantly higher (P < 0.05) on the symptomatic side, especially at 1 level below. This observational study with magnetic resonance imaging and histology showed that muscle degeneration was more common on the concave side in patients with DLS. Radiculopathy and spinal deformity may contribute to the PVM degeneration.
    Spine 02/2012; 37(16):1398-406. · 2.16 Impact Factor
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    ABSTRACT: Prospective cohort study. To elucidate the prognostic factors indicating reduced activities of daily living (ADL) at the time of the 6-month follow-up after osteoporotic vertebral fracture (OVF). OVF has severe effects on ADL and quality of life (QOL) in elderly patients and leads to long-term deteriorations in physical condition. Many patients recover ADL with acceleration of bony union and spinal stability, but some experience impaired ADL even months after fracture. Identifying factors predicting reduced ADL after OVF may prove valuable. Subjects in this prospective study comprised 310 OVF patients from 25 institutes. All patients were treated conservatively without surgery. Pain, ADL, QOL, and other factors were evaluated on enrollment and at 6 months. ADL were evaluated using the criteria of the Japanese long-term care insurance system to evaluate the degree of independence. We defined reduced ADL as a reduction of at least single grade at 6 months after fracture and investigated factors predicting reduced ADL after OVF, using uni- and multivariate regression analysis. ADL were reduced at 6 months after OVF in 66 of 310 patients (21.3%). In univariate analysis, age more than 75 years (P = 0.044), female sex (P = 0.041), 2 or more previous spine fractures (P = 0.009), presence of middle column injury (P = 0.021), and lack of regular exercise before fracture (P = 0.001) were significantly associated with reduced ADL. In multivariate analysis, presence of middle column injury (odds ratio [OR], 2.26; P = 0.022) and lack of regular exercise before fracture (OR, 2.49; P = 0.030) were significantly associated with reduced ADL. These results identified presence of middle column injury of the vertebral body and lack of regular exercise before fracture as prognostic factors for reduced ADL. With clarification and validation, these risk factors may provide crucial tools for determining subsequent OVF treatments. Patients showing these prognostic factors should be observed carefully and treated with more intensive treatment options.
    Spine 12/2011; 37(13):1115-21. · 2.16 Impact Factor
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    ABSTRACT: Prospective multicenter study. To identify radiographic or magnetic resonance (MR) images of fresh vertebral fractures that can predict a high risk for delayed union or nonunion of osteoporotic vertebral fractures (OVFs). Vertebral body fractures are the most common fractures in osteoporosis patients. Conservative treatments are typically chosen for OVFs, and associated back pain generally subsides within several weeks with residual persistent deformity of the vertebral body. In some patients, OVF healing is impaired and correlated with prolonged back pain. However, assessments such as plain radiograph or MR images taken during the early phase to predict high risks for nonunions of OVFs and/or poor prognoses have not been identified. A total of 350 OVF patients from 25 institutes were enrolled in this clinical study. Plain radiograph and MR images of the OVFs were routinely taken at enrollment at the respective institutes. The findings on the plain radiograph and MR images were classified after enrollment in the study. All the patients were treated conservatively without any surgical intervention. After a 6-month follow-up, the patients were classified into two groups, a union group and a nonunion group, depending on the presence of an intravertebral cleft on plain radiograph or MR images. The associations of the images from the first visit with those of the corresponding nonunions at the 6-month follow-up were analyzed by multivariate logistic regression to elucidate specific image characteristics that may predict a high risk for nonunion of OVFs. Forty-eight patients (49 vertebrae) among the 350 patients (363 vertebrae) were classified as nonunions, indicating a nonunion incidence of 13.5% for conventional conservative treatments for OVFs. The statistical analyses revealed that a vertebral fracture in the thoracolumbar spine, presence of a middle-column injury, and a confined high intensity or a diffuse low intensity area in the fractured vertebrae on T2-weighted MR images were significant risk factors for nonunion of OVFs. The results of this study revealed significant relationships between plain radiograph and MR images of acute phase OVFs and the incidence of nonunion. As these risk factors are defined more clearly and further validated, they may become essential assessment tools for determining subsequent OVF treatments. Patients with one or more of the earlier-described risk factors for nonunion should be observed carefully and provided with more intensive treatments.
    Spine 01/2011; 36(15):1229-35. · 2.16 Impact Factor
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    ABSTRACT: The authors compared the clinical outcomes of microscopic bilateral decompression via a unilateral approach (MBDU) for the treatment of degenerative lumbar scoliosis (DLS) and for lumbar canal stenosis (LCS) without instability. The authors also compared postoperative spinal instability in terms of different approach sides (concave or convex) following the procedure. The authors retrospectively reviewed data obtained in 50 consecutive patients (25 in the DLS group and 25 in the LCS group) who underwent MBDU; the minimum follow-up period was 2 years. Patients with DLS were divided into 2 subgroups according to the surgical approach side: a concave group (23 segment) and a convex group (17 segments). The Japanese Orthopaedic Association Scale scores for the assessment of low-back pain were evaluated before surgery and at final follow-up. The Japanese Orthopaedic Association Scale scores and recovery rates were compared between the DLS and LCS groups, and between the convex and concave groups. Cobb angle and scoliotic wedging angle (SWA) were evaluated on standing radiographs before surgery and at final follow-up. Facet joint preservation (the percentage of preservation) was assessed on pre- and postoperative CT scans, compared between the LCS and DLS groups, and compared between the concave and convex groups. The influence of approach side on postoperative progression of segmental instability was also examined in the DLS group. The mean recovery rate was 58.7% in the DLS and 62.0% in the LCS group. The mean recovery rate was 58.6% in the convex group and 60.6% in the concave group. There were no significant differences in recovery rates between the LCS and DLS groups, or between the DLS subgroups. The mean Cobb angles in the DLS group were significantly increased from 12.7° preoperatively to 14.1° postoperatively (p < 0.05), and mean preoperative SWAs increased significantly from 6.2° at L3-4 and 4.1° at L4-5 preoperatively to 7.4° and 4.9°, respectively, at final follow-up (p < 0.05). There was no significant difference in percentage of preservation between the DLS and LCS groups. The mean percentages of preservation on the approach side in the DLS group at L3-4 and L4-5 were 89.0% and 83.1% in the convex group, and those in the concave group were 67.3% and 77.6%, respectively. The percentage of preservation at L3-4 was significantly higher in the convex than the concave group. The mean SWA had increased in the concave group (p = 0.01) but not the convex group (p = 0.15) at final follow-up. The MBDU can reduce postoperative segmental spinal instability and achieve good postoperative clinical outcomes in patients with DLS. The convex approach provides surgeons with good visibility and improves preservation of facet joints.
    Journal of neurosurgery. Spine 12/2010; 13(6):758-65. · 1.61 Impact Factor
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    ABSTRACT: Retrospective study of multivariable analysis for the risk factors of motor deficit associated with lumbar disc herniation (LDH). To identify the risk factors for motor deficit and delayed recovery after surgery in patients with LDH. LDH can cause motor deficit as well as pain and sensory disturbance. Even though motor deficit can lead to disabilities and affect treatment plans, few studies have described motor deficit and its risk factors in LDH patients. Seventy-six consecutive patients who underwent microsurgical or microendoscopic discectomy for LDH at the L4/5 level were retrospectively reviewed. Motor deficit was defined as tibialis anterior muscle strength of lower than grade 4 by the manual muscle test, and delayed recovery was defined as cases requiring longer than 3 months to achieve complete recovery. The possible risk factors including sex, age, symptom duration, preoperative radiographic parameters, and type of herniation were evaluated by multivariate logistic regression analysis. Forty-three patients (56.6%) suffered from motor deficit before surgery. Forty cases (93%) completely recovered within a mean duration of 4 months. Multivariate logistic regression analysis revealed that noncontained-type (P=0.012, odds ratio=13.7) and migrated herniated nucleus pulposus (P=0.033, odds ratio=9.8) were important risk factors for motor deficit. Furthermore, severe motor deficit (preoperative manual muscle test≤3; P=0.019, odds ratio=19.6) and noncontained type (P=0.049, odds ratio=5.17) were identified as important risk factors for delayed recovery. Noncontained-type or migrated herniated nucleus pulposus seem to be the most important risk factors for motor deficit in LDH, whereas severe motor deficit and noncontained type seem to be associated with delayed recovery. The treatment options for patients with these factors at first visit should be carefully chosen during the follow-up period.
    Journal of spinal disorders & techniques 10/2010; 24(1):1-5. · 1.21 Impact Factor
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    ABSTRACT: The purpose of this study was to examine factors affecting the severity of neurological deficits and intractable back pain in patients with insufficient bone union following osteoporotic vertebral fracture (OVF). Reports of insufficient union following OVF have recently increased. Patients with this lesion have various degrees of neurological deficits and back pain. However, the factors contributing to the severity of these are still unknown. A total of 45 patients with insufficient union following OVF were included in this study. Insufficient union was diagnosed based on the findings of vertebral cleft on plain radiography or CT, as well as fluid collection indicating high-intensity change on T2-weighted MRI. Multivariate logistic regression analysis was performed to determine the factors contributing to the severity of neurological deficits and back pain in the patients. Age, sex, level of fracture, duration after onset of symptoms, degree of local kyphosis, degree of angular instability, ratio of occupation by bony fragments, presence or absence of protrusion of flavum, and presence or absence of ossification of the anterior longitudinal ligament (OALL) in the adjacent level were used as explanatory variables, while severity of neurological deficits and back pain were response variables. On multivariate analysis, factors significantly affecting the severity of neurological deficits were angular instability of more than 15 degrees [adjusted odds ratio (OR), 9.24 (95% confidence interval, CI 1.49-57.2); P < 0.05] and ratio of occupation by bony fragments in the spinal canal of more than 42% [adjusted OR 9.23 (95%CI 1.15-74.1); P < 0.05]. The factor significantly affecting the severity of back pain was angular instability of more than 15 degrees [adjusted OR 14.9 (95%CI 2.11-105); P < 0.01]. On the other hand, presence of OALL in the adjacent level reduced degree of back pain [adjusted OR 0.14 (95%CI 0.03-0.76); P < 0.05]. In this study, pronounced angular instability and marked posterior protrusion of bony fragments in the canal were factors affecting neurological deficits. In addition, marked angular instability was a factor affecting back pain. These findings are useful in determining treatment options for patients with insufficient union following OVF.
    European Spine Journal 05/2009; 18(9):1279-86. · 2.47 Impact Factor
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    ABSTRACT: Brown tumor is not a true tumor, being an unusual reactive lesion in association with primary or secondary hyperparathyroidism. We report a 23-year-old woman, who initially presented with lower back pain caused by ureterolithiasis. The initial diagnosis of brown tumor was delayed, but later pain in her leg worsened and a sacral lesion was incidentally discovered on lumbar magnetic resonance imaging (MRI); multiple destructive bone lesions were then found radiologically. The radiological features of the multiple bone lesions, which mimicked multiple metastatic tumors, seemed to be those of the terminal stage of malignancy. However, pathological examination and abnormal laboratory data showing elevated serum calcium, alkaline phosphatase, and parathyroid hormone and low serum phosphate confirmed the diagnosis of brown tumor. Adenoma in the parathyroid gland was confirmed and surgically resected. The clinical symptoms of bone pain, and abnormal radiological findings and laboratory data were resolved 6 months after surgery. Synthetic analysis of the clinical, radiological, and laboratory findings was necessary for the definite diagnosis of brown tumor.
    Archives of Orthopaedic and Trauma Surgery 03/2008; 128(2):149-54. · 1.36 Impact Factor
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    ABSTRACT: Spontaneous spinal epidural hematoma (SSEH) is a very rare condition, so there were few studies assessing the management criteria of SSEH. To assess the differential diagnosis and clinical results of treatment for SSEH. A retrospective chart and radiograph review of the patients with SSEH. Seven consecutive patients with SSEH who were treated in our institute. Differential diagnosis, severity of the paresis, and treatment selection were assessed preoperatively and postoperatively. We assessed the relationship between the following parameters and clinical results: (1) the initial symptoms, (2) imaging diagnosis of magnetic resonance imaging (MRI), (3) treatment selection (conservative or surgical treatment), (4) the interval of surgery, and (5) the severity of paresis using ASIA impairment scale (AIS) grading. In all patients, the symptoms at onset were severe neck and back pain. MRI showed isointensity to the spinal cord in the T1-weighted view and iso- or high intensity in the T2-weighted view. A solid pattern in MRI was shown in 4 patients, and a mosaic pattern was shown in 3 patients. Decompression was performed in five cases, and spontaneous recovery appeared in two cases. The mean interval time for operation was 29.8 hours. The severity of paresis was grade B in 3 cases and grade C in 4 cases at onset. These cases recovered to become grade E in 3 cases and grade D in 4 cases. Neurological deficits were present in two patients with conservative therapy and in two patients with a long interval for operation. Precise diagnosis without delay and rapid surgical treatment are essential for the management of SSEH.
    The Spine Journal 01/2008; 8(3):534-7. · 3.36 Impact Factor
  • Spine 01/2008; · 2.16 Impact Factor
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    ABSTRACT: Spontaneous regression of an osteochondroma is an infrequent event. In this report, two cases with spontaneous regression of osteochondromas are presented. The first case was a solitary osteochondroma of the pedunculated type involving the right proximal humerus in a 7-year-old boy. This lesion resolved over 15 months of observation. The second case was a 3-year-old girl with multiple osteochondromatosis, in whom sessile osteochondromas of the right tibia and left fibula regressed over 33 months. The mechanism of this phenomenon is discussed with a review of previous reports. Regarding treatment, careful observation may be acceptable for typical osteochondromas, especially in young children.
    Skeletal Radiology 07/2007; 36(6):531-4. · 1.74 Impact Factor

Publication Stats

67 Citations
27.83 Total Impact Points

Institutions

  • 2012–2013
    • Osaka City General Hospital
      Ōsaka, Ōsaka, Japan
  • 2008–2013
    • Osaka City University
      • Department of Orthopaedic Surgery
      Ōsaka-shi, Osaka-fu, Japan
    • Yodogawa Christian Hospital
      Ōsaka, Ōsaka, Japan