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Biomedical subjects

Naohisa Miyakoshi

Publications and source records attributed to Naohisa Miyakoshi.

At least 19 recordsLinked to original sources
PubMed2007

Insufficiency fracture of the sternum simulating myocardial infarction: case report and review of the literature.

Insufficiency fracture is a type of stress fracture that occurs when stress is applied to the bone with less than the normal elastic resistance, as in osteoporosis. Insufficiency fracture of the sternum is rare among all kinds of fractures. We describe two cases with insufficiency fractures of the sternum secondary to osteoporosis and thoracic kyphotic deformity. Both of the present cases, a 76-year-old woman and a 65-year-old woman, presented with severe anterior chest pain simulating myocardial infarction. However, cardiopulmonary examinations including chest radiographs, electrocardiograms, and laboratory tests were normal. Lateral radiographs of the sternum in both patients showed insufficiency fractures of the sternum. Conservative treatment with rib bandaging/bracing and analgesics relieved their symptoms. Clinical behavior, type of sternal insufficiency fractures, and mechanism of the fracture are reviewed from perusal of the literature. We emphasize that sternal insufficiency fracture should be considered in the differential diagnosis of acute chest pain in the elderly along with myocardial infarction or pulmonary embolism.

Aged↗
PubMed2006

Effects of alfacalcidol alone or in combination with elcatonin on incidence of osteoporotic vertebral fractures in postmenopausal women with spondylosis.

Osteoporosis and spondylosis often occur simultaneously. However, there are no previous reports about the effects of osteoporosis medication on incidence of vertebral fractures in people with spondylosis. In this study, we conducted a retrospective investigation of the effects of alfacalcidol alone or in combination with elcatonin on incidence of osteoporotic vertebral fractures in women with spondylosis. The present subjects were 101 postmenopausal women with osteoporosis aged >60 years, divided into three groups: D group (n = 45), treated for >5 years with alfacalcidol; D+ECT group (n = 26), treated for >5 years with alfacalcidol plus elcatonin; control group (n = 30), who received no medications for >5 years. Over the 5-year treatment period, bone mineral density (BMD) of the lumbar spine and proximal femur did not significantly change in the D and D+ECT groups, but they significantly decreased in the control group (P < 0.05). The number of incident vertebral fractures per patient was significantly higher in the control group (2.9) than in the D group (1.2) and D+ECT group (1.5) (P < 0.01). There was no significant difference in BMD or incident vertebral fractures between the D and D+ECT groups. In all three groups, the number of incident vertebral fractures positively correlated with the number of prevalent vertebral fractures (0.303 </= r </= 0.434), and negatively correlated with baseline BMD (-0.703 </= r </= -0.326) and the osteophyte score representing the degree of spondylosis (-0.769 </= r </= -0.365). Further multiple regression analysis revealed that the medication (D or D+ECT, P < 0.001) and the osteophyte score (P < 0.001) were the most significant contributors for the number of incident vertebral fractures. In conclusion, elcatonin had no additive effects on BMD or prevention of vertebral fractures in postmenopausal women receiving alfacalcidol. Presence of spondylosis (indicated by a high osteophyte score) appears to have an effect on prevention of vertebral fractures.

Aged↗
PubMed2006

Dural substitute with polyglycolic acid mesh and fibrin glue for dural repair: technical note and preliminary results.

BACKGROUND: An ideal dural substitute that enables watertight closure, has sufficient strength, and can be absorbed without remnant materials that induce inflammation, adhesion, and infection is not available. The purpose of this study was to evaluate the efficacy of a bioabsorbable polyglycolic acid (PGA) mesh and fibrin glue as a substitute for dural repair. METHODS: Altogether, 10 patients with noted dural tears during extradural spinal surgery and 20 patients who underwent durotomy for intradural spinal surgery were included in this study. In a series of 20 consecutive cases, dural closure was performed by suture and fibrin glue. In the subsequent 10 consecutive patients, dural closure was performed by suture and fibrin glue with the use of absorbable PGA mesh. The medical records and magnetic resonance imaging (MRI) of the surgical site were retrospectively reviewed to evaluate the presence of a cerebrospinal fluid (CSF) fistula or leakage after the surgery. RESULTS: A CSF fistula occurred in five patients who underwent dural repair with fibrin glue alone, and postoperative MRI showed CSF leakage in two patients with incidental dural tears after laminectomy for ossification of ligamentum flavum. No CSF fistula was present in patients who underwent dural repair using PGA mesh and fibrin glue, and no adverse effects or complications were encountered postoperatively. Follow-up MRI revealed no evidence of CSF leakage around the reconstructed dura mater. CONCLUSIONS: The use of PGA mesh and fibrin glue for the repair of dura mater is a useful method of preventing CSF leakage in spinal surgery.

Adolescent↗
PubMed2006

Clinical features of cauda equina tumors requiring surgical treatment.

In this study, we evaluated the clinical features of cauda equina tumors requiring surgical treatment. Medical records of 28 patients with cauda equina tumors (13 men and 15 women) undergoing surgical treatment were retrospectively reviewed. The majority of histological diagnoses indicated schwannoma (23 cases, 82%), and the remaining 5 indicated ependymoma, neurofibroma, meningioma, and ganglioneuroblastoma. In 86% of the cases, the initial symptom was pain in the lower back and/or lower extremities. Preoperatively, half of the patients had symmetrical pain in the lower back or lower extremities, severe pain in the supine position, or pain that was increased by coughing. One third of the patients needed morphine to control nocturnal pain. Tumor size, as determined by magnetic resonance imaging (MRI), correlated with preoperative symptom duration (r = 0.66, p < 0.001). These findings indicate that symmetrical lower back pain and/or pain that radiates to both lower extremities and increases in the supine position are characteristic of cauda equina tumors. The correlation between symptom duration and tumor size indicates that earlier diagnosis of this tumor is necessary. Earlier diagnosis based on these characteristic symptoms should make use of further examinations such as MRI.

Adolescent↗
PubMed2006

Chronic subdural hematoma coexisting with ligamentum flavum hematoma in the lumbar spine: a case report.

We present a case of a chronic spinal subdural hematoma combined with a ligamentum flavum hematoma in the lumbar spine treated surgically. An 83-year-old woman receiving antiplatelet medicine due to an angina suffered from pain in her lower extremity and gait disturbance after a backward fall. Radiological findings including magnetic resonance imaging (MRI) revealed hematoma in the ligamentum flavum at the level of L2 - L3 and a chronic subdural hematoma at the level from L3 to L5. Laminectomy through L2 to L5 was performed and a hematoma existing in the ligamentum flavum and cystic mass was removed. A chronic subdural hematoma was spontaneously evacuated after splitting of the dura mater and an intact arachnoid membrane was observed with no leakage of cerebrospinal fluid. Her clinical symptoms completely disappeared after surgery. To the best of our knowledge, this is the first case of combination of chronic subdural hematoma and ligamentum flavum hematoma in the lumbar spine treated by surgery. Chronic spinal subdural hematoma and hematoma in the ligamentum flavum should be considered as a cause of progressive nerve root compression in patients with anticoagulant therapy, and an appropriate pre-operative diagnosis would be needed to achieve complete decompression of subdural and epidural hematoma.

Aged, 80 and over↗
PubMed2006

Ligamentum flavum hematoma in the cervical spine - case report.

A 67-year-old man presented with a rare case of ligamentum flavum hematoma manifesting as progressive tetraplegia following cervical traction therapy. Magnetic resonance imaging of the cervical spine showed a posterior mass that was continuous with the ligamentum flavum at the C3-4 levels. Complete resection of the mass that contained brownish hemorrhage was performed, resulting in excellent symptom relief. We speculate that repeated trivial trauma to the degenerative ligamentum flavum was the main predisposing factor in the present case. Ligamentum flavum hematoma is a rare cause of spinal root or cord compression which typically occurs in the lower thoracic or lumbar spine, but may also appear in the cervical spine.

Aged↗
PubMed2006

Decompression of idiopathic lumbar epidural lipomatosis: diagnostic magnetic resonance imaging evaluation and review of the literature.

OBJECT: Idiopathic symptomatic spinal epidural lipomatosis (SEL) is a rare condition, and few reports have discussed diagnostic imaging criteria. To evaluate factors relating to its clinical symptoms, correlations between clinical features and the presence of spinal epidural fat were investigated, and the literature concerning idiopathic SEL was reviewed. METHODS: Morphological gradings of epidural fat were evaluated in seven patients with idiopathic SEL by using magnetic resonance (MR) imaging. In addition, body mass index (BMI), the number of involved vertebral levels, grade, and preoperative Japanese Orthopaedic Association (JOA) score were analyzed. Surgery resulted in symptomatic relief, with a mean JOA score recovery rate of 67.4%. Grading of epidural fat tended to display a slight negative correlation with preoperative JOA score, whereas a strong significant positive correlation was found between the number of involved vertebral levels and BMI. CONCLUSIONS: The number of involved vertebral levels and obesity are strongly correlated, whereas severity of dural compression is not always significantly associated with neurological complications. These results indicate that epidural fat of the lumbar spine contributes to neurological deficits. In addition, weight-reduction therapy appears to decrease the number of vertebral levels involved. Magnetic resonance imaging-based grading is helpful for the diagnosis and evaluation of idiopathic lumbar SEL. Moreover, symptoms and neurological findings are important for determining the surgical approach.

Adipose Tissue↗
PubMed2006

Spondylolisthesis of the thoracic spine. Case report.

The thoracic spine is stabilized in the anteroposterior direction by the rib cage and the facet joints. Spondylolisthesis of the thoracic spine is less common than that of the lumbar spine. The authors describe a rare case of thoracic spondylolisthesis in which the patient suffered back pain and myelopathy. The patient was a 44-year-old woman. Plain radiography revealed Grade I T11-12 spondylolisthesis. The pedicle-facet joint angle at T-11 was 118 degrees, greater than that of T-10 or T-12. Postmyelography computerized tomography scanning revealed posterior compression of the dural sac as well as enlargement of and degenerative changes in the facet joint at T-11. Magnetic resonance imaging showed anterior and posterior compression of the spinal cord at the level of the spondylolisthesis. To achieve posterior T10-12 decompression, the surgeons performed a laminectomy and posterolateral fusion in which a pedicle screw fixation system was placed. The patient's back pain disappeared immediately after the operation. The authors conclude that the enlargement of the pedicle-facet joint angle and the degenerative changes of the facet joint caused the thoracolumbar spondylolisthesis.

Adult↗
PubMed2005

Effects of intraarticular administration of basic fibroblast growth factor with hyaluronic acid on osteochondral defects of the knee in rabbits.

INTRODUCTION: Growth factors including basic fibroblast growth factor (bFGF) are expected to be useful tools for enhancing osteochondral repair. However, suitable carriers are required to deliver a growth factor to the injury site. We evaluated the effects of intraarticular injection of bFGF with hyaluronic acid (HA) on osteochondral repair and the potential carrier role of HA in this treatment. MATERIALS AND METHODS: Osteochondral defect was created in the medial femoral condyle of rabbits and received single or weekly intraarticular injection of bFGF (1 or 10 microg) with or without HA. Prior to the administration, bFGF was incubated with HA or vehicle-saline for 24 h at 4 degrees C. Four weeks after the initial injection, the animals were killed and the defect was evaluated grossly (12-point scale) and histologically (16-point scale). The effect of single injection of bFGF (1 microg) with HA was also compared to that of the carrier known as gelatin microspheres (GM) incorporating bFGF. RESULTS: Weekly-administered bFGF alone induced undesirable side effects such as inflammatory responses and osteophyte formation. However, weekly-administered 1 mug of bFGF with HA yielded significantly better osteochondral repair than each treatment alone in gross and histological examinations with minimal side effects (P < 0.05). Single administration of 1 microg bFGF with HA but not GM incorporating bFGF showed significantly better osteochondral repair comparing to the vehicle control (P < 0.05). CONCLUSION: Low-dose bFGF with HA was effective for osteochondral repair in rabbits. The significant osteochondral reparative role of bFGF with HA comparing with GM incorporating bFGF might be explained by the potential carrier role of HA and possible synergistic action between these two agents. The combination of HA with bFGF significantly suppressed the side effects resulting from single use of bFGF.

Adjuvants, Immunologic↗
PubMed2005

Factors related to spinal mobility in patients with postmenopausal osteoporosis.

Quality of life in patients with spinal osteoporosis is impaired by the decline of spinal mobility. However, the factors related to the spinal mobility in these patients are still unclear. We evaluated the possible factors affecting spinal mobility in patients with postmenopausal osteoporosis. A total of 128 postmenopausal women with osteoporosis aged over 50 years (mean, 70 years) were included in this study. The thoracic and lumbar kyphosis angles and range of motion (ROM) of the total spine were measured in the upright position and at maximum flexion/extension with a computer-assisted device. The paravertebral muscle thicknesses (PVMT) of thoracic and lumbar spine in the upright position were measured using an ultrasound unit. The number of vertebral fractures was evaluated with radiographs of the spine. Isometric back extensor strength (BES) was evaluated with a strain-gauge dynamometer. Correlations between these variables were then analyzed. Age (r=-0.412), lumbar kyphosis angle (r=-0.284), BES (r=0.369), PVMT at the lumbar spine (r=0.227) and the number of vertebral fractures (r=-0.260) showed significant correlations with total spinal ROM (P<0.05). However, no significant correlations were observed between the total spinal ROM and PVMT at the thoracic spine (r=-0.069) or thoracic kyphosis angle (r=-0.138). Multiple regression analysis revealed that the BES was the most significant contributor to the total spinal ROM. The present study suggests a possible association between BES and spinal mobility in patients with postmenopausal osteoporosis.

Aged↗
PubMed2005

Effects of reducing resistance, repetitions, and frequency of back-strengthening exercise in healthy young women: a pilot study.

OBJECTIVE: To determine the effects of reducing intensity or frequency of back-strengthening exercise on back extensor strength. DESIGN: Randomized controlled trial. SETTING: Exercises were performed in participants' homes. Instruction and measurements were performed at the rehabilitation center in the hospital. PARTICIPANTS: Fifty-eight healthy female volunteers (mean age, 20 y). INTERVENTIONS: Participants were assigned to 1 of 5 exercise intervention groups: control; standard protocol (STD) that has been shown to increase back extensor strength; weight reduction (WRD); repetition reduction (RRD); and frequency reduction (FRD). Back exercises involved lifting a weighted backpack while in a prone position. The study period was 12 weeks. MAIN OUTCOME MEASURE: Isometric back extensor strength. RESULTS: Back extensor strength increased significantly in all groups except the control group. The maximum increase was achieved by the STD group (39%), followed by the FRD (25%), WRD (22%), RRD (20%), and control (5%) groups. Percentage change in back extensor strength was significantly greater in the STD group than in all other groups except the FRD group. CONCLUSIONS: Back extensor strength in the WRD, RRD, and FRD groups was significantly higher at 12 weeks compared with baseline. Reductions in intensity and frequency resulted in similar effects on increases in back extensor strength.

Adolescent↗
PubMed2005

Ligamentum flavum hematoma in the rigid thoracic spinal segments: case report.

Ligamentum flavum hematoma, a rare cause of spinal nerve root and canal compression, typically occurs in the mobile lumbar spine segments. A thoracic ligamentum flavum hematoma is extremely rare--only one such case of a thoracolumbar (T11-12) lesion has been reported. The thoracolumbar region with its floating ribs, however, is structurally and biomechanically similar to the lumbar spine and its mobility is greater than the higher thoracic levels. To the best of their knowledge, the authors report the first case of a ligamentum flavum hematoma in the region of the rigid thoracic spinal segments with the contiguous rib cage. A symptomatic T9-10 ligamentum flavum hematoma is described in the case of a 66-year-old woman with compensatory thoracic lordosis secondary to the lumbar degenerative kyphosis. The hematoma was removed and the diagnosis was histologically confirmed. The authors speculate that thoracic lordosis might have contributed to the development of the hematoma because the ligamentum flavum and the facet joint were subjected to greater axial stress than in individuals with normal spinal alignment.

Aged↗
PubMed2004

Effects of parathyroid hormone on cancellous bone mass and structure in osteoporosis.

Parathyroid hormone (PTH) is the major hormonal regulator of calcium homeostasis. PTH is a potent stimulator of bone formation and can restore bone to an osteopenic skeleton, when administered intermittently. Osteoblasts are the primary target cells for the anabolic effects of PTH in bone tissue. Anabolic effects of PTH on bone have been demonstrated in animals and humans, by numerous measurement techniques including bone mineral density and bone histomorphometry. Clinically, the most important aspect of treatment for osteoporosis is prevention of fractures. Microstructural alterations, such as loss of trabecular connectivity, have been implicated in increased propensity for fracture. Recent two-dimensional (2D) and three-dimensional (3D) assessments of cancellous bone structure have shown that PTH can re-establish lost trabecular connectivity in animals and humans. These results provide new insight into the positive clinical effects of PTH in osteoporosis. In recent randomized controlled clinical trials of intermittent PTH treatment, PTH decreased incidence of vertebral and non-vertebral fractures in postmenopausal women. Thus, PTH shows strong potential as therapy for osteoporosis. However, 2D and 3D structural analysis of advanced osteopenia in animals has shown that there is a critical limit of trabecular connectivity and bone strength below which PTH cannot completely reverse the condition. Given that PTH treatment fails to completely restore trabecular connectivity and bone strength in animals with advanced osteopenia, early treatment of osteoporosis appears important and efficacious for preventing fractures caused by decreased bone strength resulting from decreased trabecular connectivity.

Animals↗
PubMed2004

The anabolic effects of GH/IGF system on bone.

Osteoporosis is the result of imbalance in bone remodeling caused by increased bone resorption and decreased bone formation. In terms of the mechanisms for the age-related impairment in bone formation, a deficiency in growth hormone (GH)/insulin-like growth factor (IGF) system that occurs with age has been proposed to play a major role. The potential causes for age-related decline in GH secretion are under active investigation and may involve multiple mechanisms including GH secretagogues, sex hormones, nutritional status and physical activity. Although a number of animal and clinical studies have provided experimental evidence for potential use of GH/IGF system components to increase bone mass, the clinical utility of GH/IGF system components for treatment of osteoporosis has not come to fruition because of our incomplete understanding of the regulation of production and actions of GH/IGF system components. Regarding the actions of GH in target tissues, there is evidence that IGF system plays a major role in mediating the GH effects. In addition, GH may also exert effects on certain target tissues independent of IGFs. It is also known that GH effects on target tissue involve multiple components of the IGF system including the ligands, receptors, IGF binding proteins (IGFBP), IGFBP proteases and activators and inhibitors of IGFBP proteases. Future studies on the mechanisms that contribute to age-related impairment in GH/IGF axis and the molecular pathways that contribute to the bone forming effects of GH/IGF axis may provide a foundation for the development of safe and effective therapies involving one or more IGF system components to correct bone formation deficit in the elderly subjects.

Animals↗
PubMed2004

[IGF-I].

Explore the source record for details and available documents.

Animals↗
PubMed2003

Inverse relation between osteoporosis and spondylosis in postmenopausal women as evaluated by bone mineral density and semiquantitative scoring of spinal degeneration.

STUDY DESIGN: The relation between bone mineral density and severity of spondylosis was evaluated in postmenopausal women. OBJECTIVE: To examine the possible inverse relation between osteoporosis and spondylosis by evaluating the association between bone mineral density and osteophyte formation or intervertebral disc narrowing using a semiquantitative scoring system. SUMMARY OF BACKGROUND DATA: The literature contains studies demonstrating an inverse relation between osteoporosis and spondylosis as well as those documenting insufficient support for such a relation. However, in these studies, only limited-range grading systems (e.g., Grades 1-4) were used to evaluate the severity of spondylosis. METHODS: In this study, 104 postmenopausal women older than 60 years underwent bone mineral density measurement of the lumbar spine (anteroposterior, lateral, and midlateral) and proximal femur (femoral neck, trochanter, and Ward's triangle) using dual-energy x-ray absorptiometry. Raw data representing the semiquantitative osteophyte score and disc score as well as the number of vertebral fractures were obtained using spinal radiograph. Correlations between bone mineral density and the radiographic variable were then analyzed. RESULTS: Significant negative correlations were found between all bone mineral density data and the number of vertebral fractures (-0.524 < or r= r < or = -0.347; P < 0.05). Marginal/moderate positive correlations were observed between the osteophyte score and the bone mineral density data (0.263 < or = r < or = 0.580, P < 0.05), and between the disc score and the bone mineral density data (0.233 < or = r < or = 0.570, P < 0.05).CONCLUSIONS On the basis of the finding that spondylotic changes in postmenopausal women exhibit positive correlations not only with the lumbar bone mineral density, but also with the remote-site bone mineral density, this study supports the view that osteoporosis has an inverse relation with spondylosis.

Aged↗
PubMed2003

Osteoporotic vertebral fracture adjacent to a nonsegmented hemivertebra.

A combination of osteoporotic vertebral fractures and congenital spinal deformity is theoretically possible, but there have been no reports on this combination in the literature. We describe a rare case of an osteoporotic vertebral fracture adjacent to the nonsegmented hemivertebra. A 60-year-old postmenopausal woman who did not recall any specific trauma presented with severe back pain. She had markedly decreased bone mineral density and significant lumbar kyphoscoliosis with a nonsegmented hemivertebra between L1 and L2 on radiographs of the lumbar spine. Magnetic resonance imaging (MRI) revealed a vertebral fracture adjacent to the nonsegmented hemivertebra. Laboratory studies showed increased serum bone-specific alkaline phosphatase (BAP) and urinary type I collagen crosslinked N-telopeptide (NTx). A thoracolumbar brace was applied for 3 months. Daily administration of alendronate normalized her serum BAP and urinary NTx levels. MRI scans of the lumbar spine after 6 months also confirmed normalized signal intensities of the fractured vertebra adjacent to the nonsegmented hemivertebra. The vertebral fracture seemed to be induced by spinal malalignment, increased stress on the adjacent level of the fused segment, and its fragility due to osteoporosis.

Bone Malalignment↗