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Biomedical subjects

T Sakou

Publications and source records attributed to T Sakou.

At least 73 records · Page 4Linked to original sources
PubMed1992

Preoperative and postoperative magnetic resonance image evaluations of the spinal cord in cervical myelopathy.

To evaluate the morphologic changes of the spinal cord in patients with cervical myelopathy due to cervical spondylosis and ossification of the posterior longitudinal ligament, the authors measured the thickness and signal intensity of the cervical cord with magnetic resonance imaging in healthy adults and patients with cervical myelopathy, and compared these findings. In patients with cervical myelopathy, the preoperative and postoperative magnetic resonance imaging findings were compared with the severity of myelopathy and postoperative results. In healthy adults, the anteroposterior diameter of the cervical cord was 7.8 mm at the C3 level and decreased at lower levels. In the patients with cervical myelopathy, the preoperative spinal anteroposterior diameter was significantly reduced at various levels corresponding to the stenosis site within the vertebral canal. In the group with ossification of the posterior longitudinal ligament, the minimal anteroposterior diameter of the cervical cord tended to decrease with increasing severity of myelopathy. However no relationship was observed between the two parameters in the cervical spondylotic myelopathy group. In the group with ossification of the posterior longitudinal ligament, surgical results were good when the postoperative anteroposterior diameter was increased, whereas in the cervical spondylotic myelopathy group there was no relationship between the two parameters. In the patients with myelopathy, a high intensity area was observed in about 40% of all patients before operation and about 30% after operation. However, the presence or absence of a high intensity area did not correlate with the severity of myelopathy or with surgical results in the group with ossification of the posterior longitudinal ligament and the cervical spondylotic myelopathy groups.

Cervical Vertebrae↗
PubMed1991

Genetic study of ossification of the posterior longitudinal ligament in the cervical spine with human leukocyte antigen haplotype.

To evaluate the genetic background of ossification of the posterior longitudinal ligament, the relationship between the presence of absence of ossification and human leukocyte antigen haplotypes was studied in 33 families of patients with ossification of the posterior longitudinal ligament. The study revealed that human leukocyte antigen haplotypes formed certain types of clusters, and that some human leukocyte antigen haplotypes were very rare in the Japanese population, suggesting the involvement of human leukocyte antigen-linked factors in the pathogenesis of ossification of the posterior longitudinal ligament of the cervical spine. In the families of these patients, ossification of the posterior longitudinal ligament was demonstrated by radiography in 56% (10/18) of the siblings. Each of these siblings shared both human leukocyte antigen haplotypes with the patient. None of those who shared only one human leukocyte antigen haplotype with the patient had developed ossification of the posterior longitudinal ligament. From these findings, the presence of both pathogenic human leukocyte antigen haplotypes is considered to be necessary for the development of ossification of the posterior longitudinal ligament, and this genetic predisposition may be activated by multiple factors, including regressive degeneration due to aging and the environment.

Cervical Vertebrae↗
PubMed1990

Displacement of the ventricular fold following cordectomy.

In order to avoid radiation and its undesirable side effects, we have employed surgical techniques for treatment of early glottic cancer when the lesion is confined to one membranous cord (Fukuda, Saito, Sato, and Kitahara: J. Jpn. Bronchoesophagol. Soc. 30: 7-14, 1979; Fukuda and Saito: Otologica 26: 434-436, 1980; Fukuda, Kawaida, Ohki, Kawasaki, Kita, and Tatehara: J. Jpn. Bronchoesophagaol. Soc. 39: 139-144, 1988). Laser is one of the most popular techniques and it has been accepted as the first choice by many authors (Annyas, Overbeek, Escajadillo, and Hoeksema: Laryngoscope 94: 836-838, 1984; Mcguirt and Koufman: Arch. Otolaryngol. Head Neck Surg. 113: 501-505, 1987; Tsuji, Fukuda, Kawaskai, Kawaida, and Kanzaki: Keio J. Med. 38: 413-418, 1989). However, some cases are difficult to approach by direct laryngoscopy, requiring an external way to expose the lesion. In these cases, cordectomy by laryngofissure is the method of choice, but the function of the glottis could be improved by replacing the excised cord displacing the ventricular fold. This technique, designed by the authors, was carried out in 22 patients and the results from the viewpoint of phonodynamics, voice quality, and cure rate are discussed in this study. The results are encouraging and we believe that this method is a very reasonable alternative to the laser when such equipment is not available. We also believe that late side effects and oncogenic problems associated with radiation are important points to be considered, especially in patients of relatively younger age.

Adult↗
PubMed1990

Dynamic analysis of the Harrington system using a spinal simulator.

The authors constructed a spinal simulator for the thoracolumbar spine with mechanical properties similar to those of cadaver specimens, and studied the effectiveness of the Harrington system in unstable fractures of the thoracolumbar spine. Distraction and compression rods were applied under various conditions. External bending moment was applied to the model to measure the internal bending moment on the vertebral body and ligaments. Optimal spinal stability was obtained when the distraction system was combined with the compression system with hooks at laminas three levels above and below the fracture.

Adult↗
PubMed1990

Natural history of degenerative spondylolisthesis. Pathogenesis and natural course of the slippage.

To clarify the natural course of degenerative spondylolisthesis, the mechanism and progression of disk slippage were studied clinically and radiographically in 40 patients. Progressive slippage was observed in 12 patients (30%). No progression of slippage was noted in patients who showed narrowing of the intervertebral disk, spur formation, subcartilaginous sclerosis, or ossification of ligaments. These suggest that the mechanisms of spinal restabilization prevent progression of the disease. General joint laxity was observed in many patients (65%), and this was believed to be involved in the pathogenic mechanism of this disease. There was no correlation between the clinical symptoms and progression of slippage. These findings suggest that careful consideration of the natural mechanisms of spinal restabilization as well as the natural course of the disease is important.

Female↗
PubMed1989

Magnetic resonance imaging of upper cervical disorders in rheumatoid arthritis.

Upper cervical spine was examined with magnetic resonance imaging (MRI) and conventional roentgenograms in 55 patients with rheumatoid arthritis. The MRI findings were compared with various values determined in roentgenograms: the atlanto-dental interval (ADI), the space available for the spinal cord (SAC), and the Ranawat and Redlund-Johnell values. In patients with vertical settling (VS), MRI showed medullary compression in all those with abnormal Redlund-Johnell values and Ranawat values of 7 mm or less. In patients with anterior atlanto-axial subluxation, compression of the upper cervical cord was observed in all patients with SAC of 13 mm or less and many of those with ADI of 8 mm or greater. This study indicated that medullary compression can be estimated by these values determined in roentgenograms of the cervical spine.

Adult↗
PubMed1989

Vertical settling in rheumatoid arthritis. Diagnostic value of the Ranawat and Redlund-Johnell methods.

The usefulness of the recently developed Ranawat and Redlund-Johnell craniometric methods was compared with that of the conventional McGregor method for diagnosing vertical settling (VS) of the skull and the atlas on the axis in 209 patients with rheumatoid arthritis (RA). Statistical analysis of the values obtained from roentgenograms revealed close correlations among the three methods. The first two methods were superior to the McGregor method because the measuring points could be identified on plain roentgenograms of the cervical spine in virtually all cases. The McGregor value could not be determined in 38 (18%) patients. Since medullary compression could be detected by magnetic resonance imaging in all patients who showed abnormal Redlund-Johnell values, the Redlund-Johnell method may be useful for diagnosing advanced VS. It also detects not only atlantoaxial lesions but also atlantooccipital lesions. Thus, the Redlund-Johnell method appears to be the best method for diagnosing VS in RA patients.

Adult↗
PubMed1989

Occipitoatlantoaxial fusion utilizing a rectangular rod.

Atlantoaxial subluxation has been treated conventionally by Gallie posterior fusion. This technique, however, has disadvantages such as the frequent occurrence of pseudarthrosis, a high probability of relapse, and the necessity of long-standing strict external fixation until bone fusion. To overcome these problems, posterior occipitoatlantoaxial fusion was performed using a rectangular rod that assures strong internal fixation in 16 patients with atlantoaxial subluxation. The condition was complicated by superior migration of the dens in five patients. Clinical and roentgenographic examinations before and after the operation showed improvements in neurological symptoms and in pain in the neck and occipital region in all patients. Bone fusion was observed in all patients and reduction, performed to the extent possible during the operation, was retained adequately. The present method, which provides strong internal fixation, allows bone fusion and early initiation of rehabilitation with a simple external support of the neck. It also facilitates laminectomy of C1 in patients with associated myelopathy. This procedure, therefore, is particularly effective in patients with marked instability or with rheumatoid arthritis and makes postoperative application of a halo vest or skull traction unnecessary.

Adolescent↗
PubMed1987

Upper cervical involvement in rheumatoid arthritis.

Atlanto-axial dislocation and upward migration of the odontoid were studied in patients with rheumatoid arthritis treated conservatively and those treated by atlanto-axial posterior fusion. Upward migration of the odontoid was evaluated by Ranawat's and Redlund-Johnell's methods after determining the normal range in healthy Japanese adults. Of the 100 patients treated conservatively, atlanto-axial dislocation was found in 49% and upward migration of the odontoid in 26% by the former method, and in 8% by the latter method. The detection rate of these lesions increased with the increase in the duration of the disease and progression of rheumatoid lesions. Abnormal Ranawat values are associated with lesions in the C1-C2 segment and abnormal Redlund-Johnell values with 0-C2 lesions. The latter suggests severe conditions and seems to be a useful indicator for the diagnosis of upward migration of the odontoid in our study. Though rheumatoid lesions in the upper cervical spine mainly involved the C1-C2 level, marked deterioration of the atlanto-occipital joints was also occasionally observed. Therefore, in surgical treatment, attention should be paid also to this region. Patients with abnormal Redlund-Johnell values require spinal fixation including the occipital bone.

Adult↗
PubMed1987

Congenital defect of posterior elements of the axis.

A congenital defect of the posterior elements (spinous process and vertebral arch) of the axis was observed in a 20-year-old man. This anomaly was detected by coincidence during roentgenographic study of the cervical spine for the investigation of headaches and neck pain following trauma. The clinical symptoms were relieved by conservative therapy, and the patient returned to a normal life.

Adult↗
PubMed1985

Effects of pulsed electromagnetic field on growth and differentiation of embryonal carcinoma cells.

A murine embryonal carcinoma cell line (F9) was used to examine the effect of a pulsed electromagnetic field on the growth and differentiation of malignant cells. The cells can be induced to differentiate into parietal endodermal cells by treatment with retinoic acid. The pulsed electromagnetic field (1 Gauss and 10 Gauss) promoted the growth of embryonal carcinoma cells in both the presence and absence of retinoic acid. The pulsed electromagnetic field was also found to inhibit retinoic acid-induced differentiation, when the degree of differentiation was based on morphological criteria or on the production of plasminogen activator.

Animals↗
PubMed1983

Congenital absence of a vertebral pedicle in the cervical spine. A case report.

Congenital absence of a vertebral pedicle in the cervical spine, a rare disorder, was observed in a 41-year-old woman. The disorder may be confused with a "dumbbell" tumor and erosion by a tortuous vertebral artery. The diagnosis is established by characteristic radiologic changes, especially in oblique roentgenograms, myelograms, and CT scans. Nerve root decompression was performed by hemilaminectomy at the level of the fifth cervical vertebra. There was little relief of pain, the chief preoperative complaint. Surgery may not be indicated for patients with congenital absence of a vertebral pedicle.

Adult↗
PubMed1979

Ossification of the posterior longitudianl ligament of the cervical spine: subtotal vertebrectomy as a treatment.

If the ossification is localized in the central part of the intervertebral space, anterior decompression surgery of Cloward may be indicated. However, if most posterior ligamentous ossification covers the posterior surface of the vertebral body and the lateral sides, Cloward's method is not indicated. We have developed a method of anterior decompression and fusion surgery to clear the ossified area, resecting the vertebral body (subtotal vertebrectomy). The results were excellent in 3 of 4 patients with preoperative radiculopathy; there were 2 excellent and 16 good results in 22 patients with myelopathy. Of course laminectomy can produce some good effects, but the anterior obstruction removes through the anterior approach. Anterior decompression may be indicated when ossification is localized below the C3--4 intervertebral space, and when the spinal canal is not narrowed in the upper cervical region, even if ossification extends over the whole cervical spine. Laminectomy is advised when ossification involves all levels of the cervical spine, the upper cervical spine is narrowed or the sagittal dimension of the spinal canal is reduced more than 60%.

Cervical Vertebrae↗