Hisatoshi Baba

Ganglion cyst of the posterior longitudinal ligament causing lumbar radiculopathy: case report

We describe a man aged 26 years who presented with a neurological syndrome, which was found on lumbar radioculopathy to be due to a ganglion cyst originating from the posterior longitudinal ligament. Based on MRI findings, a cystic lesion was suspected, a round lesion at L4 level with no connection to the adjacent facet or to the dura matter. During surgery, a liquid-containing cystic lesion was found to originate from the posterior longitudinal ligament at L4 level. The resected cyst was diagnosed histologically as a ganglion cyst. A complete cure was established after surgery and no recurrence was noted at a follow-up 1.7 years postoperatively. A ganglion cyst of the posterior longitudinal ligament should be considered in the differential diagnosis of a cyst in the lumbar region causing neurological complications.

Three-dimensional topographic analysis of spinal accessory motoneurons under chronic mechanical compression: an experimental study in the mouse.

We investigated the effect of chronic mechanical compression of the cervical spinal cord on the number of spinal accessory motoneurons in 25 tiptoe-walking Yoshimura mice. The animals had calcified deposits in the atlantoaxial membrane at the C1-C2 vertebral level, compressing the spinal cord posterolaterally. Motoneurons of the spinal accessory nerve between C1 and C5 segments were labelled using wheat germ agglutinin-horseradish peroxidase (WGA-HRP) injected into the sternocleidomastoid muscles. The counted cells were processed into a three-dimensional computer display to analyse the cytoarchitectonic changes caused by external cord compression. The number of WGA-HRP-labelled spinal accessory motoneurons was significantly reduced on the affected side. The number of motoneurons in compromised C2 and C3 cord segments correlated linearly with the extent of mechanical compression, but no such relationship was present on the contralateral side. There was an increase in the number of WGA-HRP-labelled spinal accessory motoneurons in the medial cell pools of the anterior grey horn at a level most rostral to the compression, and in the ventrolateral cell pools at levels immediately rostral to the compression. Our findings suggest that the spinal accessory motoneurons translocate rostral to the area of external compression in order to avoid mechanical injury.

Local spread of metastatic vertebral tumors: A histologic study

Study Design. Nineteen solitary metastatic vertebral tumors obtained by total en bloc spondylectomy were analyzed histologically. Objectives. To determine the mechanisms of local spread of vertebral tumors and identify barrier tissues to tumor progression in the vertebra. Summary of Background Data. Histologic studies of specimens resected at amputation or en bloc excision have determined the pattern of local spread of bone and soft tissue tumors in the extremities and identified barrier tissues to tumor spread. However, a similar assessment of vertebral malignancies is difficult. The development of total en bloc spondylectomy for primary vertebral malignancy and solitary metastases has allowed the collection of tissue samples sufficient to analyze the pattern of local spread of tumors, using the concept of compartment and barrier. Methods. Histologic sections of all vertebral elements were prepared from specimens collected after en bloc spondylectomy. Serial 5‐mm sections in the sagittal plane were also prepared and examined. Results. Analysis of tumor location showed that metastatic tumors reached the vertebral column by invading the bone marrow of the dorsal region of the vertebral body. The anterior longitudinal ligament, posterior longitudinal ligament, periosteum abutting the spinal canal, ligamentum flavum, periosteum of the lamina and spinous process, interspinous ligament, supraspinous ligament, cartilaginous endplate and the anulus fibrosus served as barriers to tumor progression. The posterior longitudinal ligament was the weakest barrier tissue and was gradually destroyed by the tumor at the point of perforating vessels. Even after destruction of the barrier tissue, tumor cells were covered with a thin, fibrous reactive membrane. Two pathways allowed tumor spread to the adjacent vertebrae: 1) from the edge of the vertebral body to the adjacent vertebral body beneath the longitudinal ligament, and 2) through the paravertebral muscles to the neighboring lamina. Conclusions. Each vertebra can be represented by a compartment surrounded by several barriers. The most common path for tumor spread is through the posterior longitudinal ligament to the epidural space.

Spontaneous remission of a solitary intraspinal synovial cyst of the lumbar spine

Abstract We report on a 15-year-old boy in whom a spontaneous remission of a symptomatic synovial cyst, possibly emanating from the L4-5 facet joint, was noted. The medical history suggested that sport-related overactivity and/or minor trauma was the underlying cause. Conservative treatment for several months may be one treatment option if the cyst wall is not calcified and the symptoms and signs related to radiculopathy show a gradual decrease.

Plasticity of the spinal cord contributes to neurological improvement after treatment by cervical decompression. A magnetic resonance imaging study.

Abstract To investigate the relationship between morphological plasticity of the spinal cord and neurological outcome after surgery for compressive lesions, we correlated the transverse area of the cervical spinal cord measured by transaxial magnetic resonance imaging (MRI) obtained during the early postoperative period (1–6 months) with neurological function assessed at a median postoperative follow-up period of 2.5 years. Measurements on MRI in 56 patients (35 men and 21 women) included evaluation of the cross-sectional area of the cervical cord and the subarachnoidal space at the level of decompression. The transverse area of the cervical cord increased by 30 to 62% postoperatively and that of the subarachnoidal space by 57 to 95%. Neurological improvement was noted in all patients and averaged 63% in our assessment scale. Expansion of the cervical cord during the early postoperative period correlated significantly with the late postoperative neurological status (P = 0.009). Our results suggest that an increase in the cross-sectional area of the cervical spinal cord, representing spinal cord morphological plasticity, is a significant factor in determining the late neurological improvement following decompressive surgery.

Regulation of vasomotion of arterioles and capillaries in the cat spinal cord: role of α actin and endothelin-1

Ring-shaped vasoconstrictions of arterioles at their branching sites have often been reported in vascular corrosion casts of the brain and spinal cord in rats and cats. It is surmised that smooth muscle cells in arteriolar walls could regulate the blood flow by changing the diameter of the lumen (ie vasomotion). However, few reports have described vasomotion at the capillary (capillaries have no smooth muscle cells). Also, there have been no reports on endothelin-1 in the arterioles and capillaries of the spinal cord. This study was designed to determine (1) the electron microscopic architecture of vasomotion; (2) the immunohistochemical identification of α actin and endothelin-1 in the arterioles and capillaries of the spinal cord. Twenty-seven adult mongrel cats were used to study vascular corrosion casts at the lumbosacral spinal cord segments immunohistologically and through scanning electron microscopic observations. Sections of the spinal cord were stained with monoclonal anti-α actin and endothelin-1 antibodies. Vascular corrosion casts demonstrated two types of vasomotion: a sausage-like peristalsis and a ring-shaped vasoconstriction at the arteriole and capillary levels. In the immunohistological study, α actin and endothelin-1 were identifiable in the vascular wall at the bifurcation, and pericytes were found to contain microfilaments of α actin. The ring-shaped vasoconstriction might be regulated by smooth muscle cells in arterioles and by pericytes in capillaries by releasing endothelin-1.

Symptomatic arachnoiditis ossificans of the thoracic spine. Case report

This report describes a man aged 65 years who developed spastic paraparesis secondary to arachnoiditis ossificans in the thoracic spine. Over 35 years previously, in Southeast Asia, the patient had received repeated lumbar punctures in the treatment of meningitis possibly associated with malarial fever. He had multiple arachnoidal ossifications located at levels from T6 to T9 dorsal to the spinal cord which were well delineated by computed tomography. The lesions were completely extirpated by dorsal route surgery, and the patient had marked neurological improvement after surgery. Histology confirmed that the lesions showed mature bone that formed with an osseous marrow and trabeculae, and the lesions exhibited clusters of arachnoidal cells as well as the proliferation of osteoblasts surrounding the ossified area. Early diagnosis and surgical intervention, however, are mandatory in such cases, if the patient is to attain an acceptable degree of recovery.

Fit and fill analysis of a newly designed femoral stem in cementless total hip arthroplasty for patients with secondary osteoarthritis

The fit and fill of the femoral canal are critical to the success of cementless femoral stems in total hip arthroplasty. It is difficult for conventional stems to provide a good fit and fill for the femora of patients with secondary osteoarthritis. Based on measurements of 100 femora of these patients, we designed two types of Fukui Medical School (FMS) stems with a proximal lateral flare that differed in the medial radius. We compared the fit and fill of the FMS stems with those of four conventional stems, using computer simulation. The mean proximal fit and total fit of the FMS stems were 46% and 53% respectively, a significant improvement compared with the other stems examined. The mean fill of FMS stems was 82% at the lower end of the lesser trochanter and 84% at the upper end of the isthmus, values that were significantly higher than those of the other stems. Since September 1995, we have implanted FMS stems in 15 hips with secondary osteoarthritis. Radiographic evaluations showed that the canal fill of the FMS stems was significantly greater in the proximal femur compared with other stems previously inserted at our department.

Clinical Study of Spinal Cord Evoked Potentials

The author’s experience with ascending SEPs during 36 cases of spinal surgery is reported. Qualified SEP was obtained in 10 of 12 who underwent anterior spinal surgery and in 19 of 24 with posterior spine surgery. In anterior spinal surgery, 4 cases (40%) showed amplitude attenuations more than 30% of baseline amplitude, and in posterior spinal surgery, more than 30% amplitude attenuation was seen in 5 cases (26%) with laminoplasty. There were two cases which showed more than 50% amplitude attenuation; however, postoperative results were not catastrophic (54).

Bone grafting in cementless total hip replacement for congenital dysplasia of the hip.

Abstract We reviewed 27 cementless primary total hip replacements in patients with osteoarthrosis secondary to congenital dysplasia of the hip. Autogenous bone grafting was used as augmentation. On average the follow-up period was 9 years. Two hips were revised and three acetabular components were considered loose. In hips with loose cups the average graft coverage was significantly greater than in stable hips. The use of a cementless acetabular component is encouraging for reconstruction, although extensive grafting should be avoided. Our study suggests that cementless reconstruction in dysplastic hips yields a satisfactory outcome.Résumé Nous avons examiné 27 arthroplasties sans ciment chez les patients avec arthrose secondaire à une dysplasie congénitale de la hanche. Une greffe d’os autogène a été utilisé comme augmentation. La période moyenne de suivi a été 9 années. 2 hanches ont été révisées et 3 composants acetabulaires ont été descellés. Dans la hanche ayant les composants descellés, la couverture moyenne de la greffe était significativement supérieure à celle des hanches stables. L’utilisation des composants acetabulaires sans ciment est encouragée pour la reconstruction, bien que la greffe massive doive être évitée. Notre étude suggère que l’arthroplastie sans ciment avec greffe autogène pour les hanches dysplasiques est associée à un résultat satisfaisant.