Biomedical subjects

M Akino

Publications and source records attributed to M Akino.

At least 37 records · Page 2Linked to original sources

PubMed1993

Spinal cord evoked potential monitoring after spinal cord stimulation during surgery of spinal cord tumors.

Spinal cord evoked potentials (SCEPs) after spinal cord stimulation were used as a method of spinal cord monitoring during surgery of 6 extramedullary and 14 intramedullary spinal cord tumors. SCEPs were recorded from an epidural electrode placed rostral to the level of the tumor. Electrical stimulation was applied on the dorsal spinal cord from a caudally placed epidural electrode. The wave forms of SCEPs consisted of a sharp negative peak (N1) in 15 cases and two negative peaks (N1 and N2) in 5 cases. The N2 wave was markedly attenuated by posterior midline myelotomy, whereas the N1 activity showed less-remarkable changes by myelotomy. An increase in N1 amplitude was observed after the removal of the tumor in four extramedullary and three intramedullary cases. Of six patients that showed decreased N1 amplitude after the removal of the tumor, five patients developed postoperative motor deficits. However, there were four false-negative cases and one false-positive case in regard to changes of N1 amplitude and postoperative motor deficits. Four false results occurred in intramedullary cases. In two of them, postoperative symptoms indicated intraoperative unilateral damage to the spinal cord. The position of the stimulating electrode, the difference in thresholds of the axons for electrical stimulation between the right and left side of the spinal cord, or the change of the distance between the electrode and the spinal cord surface may account for these false results. Thus, our analysis of the changes of SCEP wave forms and early postoperative symptoms indicates that the sensitivity of this monitoring method to detect intraoperative insults to the spinal cord is unsatisfactory in spite of the reproducible wave forms. We conclude that SCEP monitoring can be used as an alternative method or in combination with other types of evoked potentials in patients with severe spinal cord lesions who show abnormal somatosensory evoked potentials preoperatively.

Adult↗

PubMed1992

Scoliosis associated with syringomyelia presenting in children.

The clinical presentations and radiological features of scoliosis accompanying syringomyelia were analyzed in 14 cases of syringomyelia associated with a in 14 cases of syringomyelia associated with a Chiari malformation in children. Scoliosis was the initial symptom in 11 out of 16 patients (64%) with syringomyelia and present in 14 (88%) at the initial examination. The scoliosis associated with syringomyelia was characterized by a higher incidence of a single curve (6 cases, 43%) and convexity to the left (7 cases, 50%) than seen in idiopathic scoliosis. The syrinx was shifted to the convex side of scoliosis on the axial section at the middle or lower thoracic level in patients with a single curve, and at the cervical or upper thoracic level in patients with a double curve. The authors think that the scoliosis develops in children as a result of damage done to the anterior horn, which innervates the muscles of the trunk, by an asymmetrically expanded syrinx.

Arnold-Chiari Malformation↗

PubMed1992

Sacral nerve root cysts manifesting as localized unilateral perineal pain--case report.

A 62-year-old female presented with multiple sacral nerve root cysts manifesting as localized unilateral perineal pain. Myelography just after contrast material injection revealed multiple cysts at the sacral level. However, perioperative dye injection showed hardly any flow in the reverse direction. Only the S3 nerve was constricted by hyperplasia of the dura mater, and adhered to the cyst wall. Other nerves were not constricted, nor adhered to cyst walls. The S3 nerve constriction and tight adhesion was the cause of the pain. The one-way flow of spinal fluid from the spinal subarachnoid space to the cysts is probably closely correlated with cyst formation.

Cysts↗

PubMed1992

[Spinal epidural stimulation for central pain caused by spinal cord lesion].

Epidural spinal cord stimulation was carried out in 4 patients with denervation caused by spinal cord lesion, and we reviewed previously reported cases. Initial result showed at 1 week in 100% of our cases, but about 1/3 of the cases, even those with the same denervation caused by spinal cord lesion, had no pain relief at this stage in previously reported cases. In our cases, excellent pain relief was gained temporarily, even though the painful area and the spinal cord lesion were separated somatotopically in 2 cases (case 3, 4). Temporary success bore no relationship to quality and duration of pain. In all cases except case 1, a rapidly decreasing effectiveness was noted, and finally no pain relief was gained at all after 4, 3 and 5 months, respectively. In case 1 there was persistent pain relief estimated at 70-80% after 19 months, only when the spinal cord was stimulated. Epidural stimulation also produced sensations in the painful area. Spinal cord stimulation would suppress at least the dorsal horn neurons which were destroyed by various kinds of diseases. A decline in effectiveness with time would occur due to essential causes of the deafferentation pain, such as anatomical and regeneration factors.

Adult↗

PubMed1992

[Clinical application of phase contrast angiography].

"Phase Contrast Angiography" is a new technique of Magnetic Resonance Angiography as reported by Dumoulin CL et al. Using this technique, we can obtain images of vessels (angiograms) without injection of contrast medium. We present the results of phase contrast angiography on cerebral and spinal vascular disease. We utilized the General Electric SIGNA, 1.5 tesla NMR. One hundred and ninety-one cases of cerebral and spinal vascular diseases were scanned using phase contrast angiography. Included were 90 cases of occlusive vascular disease, 16 cases of moyamoya disease, 39 cases of arteriovenous malformation, and 28 aneurysms. The phase contrast angiography uses flow encoding gradient pulses, which impart a velocity-dependent phase shift to the transverse magnetization of moving spins. The resulting image contains only information from the moving spins; while information from stationary tissue remains suppressed. In cases using 3-D angiogram, we made 32 images 6 degrees apart in their projection direction and displayed them on a video terminal. We were able to visualize occlusions of vessels, aneurysms, bypassed vessels, and abnormal vessels of arteriovenous malformations. Retrospective evaluation comparing phase contrast angiography with conventional angiography of the stenotic findings on the horizontal portion of middle cerebral arteries (64 vessels of 32 patients), resulted in a false positive ratio of 39.1%. We obtained clinically valuable results regarding the hydrodynamics of patients using "phase contrast angiography" non-invasively. These results reveal not only "anatomical" images of vessels, but also "functional" images, which are sensitive to the pattern of the blood flow. This study would strongly suggest that phase contrast angiography presents a valuable tool for the clinical diagnosis of cerebral and spinal vascular diseases.

Cerebral Angiography↗

PubMed1992

[Quantitative analysis of cerebrospinal fluid dynamics in syringomyelia using cine MRI with pre-saturation].

Some reports show the qualitative analysis of cerebrospinal fluid (CSF) pulsation in the subarachnoid space and the syrinx using cine magnetic resonance imaging (MRI). However, few reports studied the quantitative analysis of CSF pulsation. We report here the results of quantitative analysis of CSF pulsation using the cine MRI with pre-saturation pulse. Using flow phantom, we calibrated the correlation between the true velocity and calculated velocity acquired from the movement of pre-saturated low signal. Three cases of syringomyelia with Chiari malformation, two cases of traumatic syringomyelia, and three normal volunteers were examined using this technique, and we could obtain time-velocity curves of CSF in both subarachnoid spaces and syrinx. Although obvious pulsation of CSF was observed in the syrinx of all Chiari malformations, no pulsation of CSF was observed in the syrinx of traumatic syringomyelia. CSF in the syrinx moves upward in the early systolic cardiac cycle, downward in the systolic cycle, and upward again in the diastolic cycle. Patterns of CSF pulsation in syrinx were similar to those in the subarachnoid space, but "phase" of these pulsations differed from case to case. These results suggest the close relationship between CSF pulsation in the syrinx and CSF obstruction at the cranio-vertebral junction. Dissociation of the "phase" of CSF pulsation in the syrinx and subarachnoid space may be significant in the analysis of the pathogenesis of syringomyelia.

Adult↗

PubMed1992

[Anterior approach for cervical dumb-bell typed neurinomas].

We experienced three cases of the dumb-bell typed cervical neurinoma. All of them compressed the spinal cord in the spinal canal, and had developed through the intervertebral foramen and compressed and displaced the vertebral artery. The decompression of the vertebral artery and reconstruction of the spine as well as the removal of the tumor were thought to be important. We used the anterior approach and were able to operate safely and completely. The anterior approach was thought to be effective for the surgical treatment of dumb-bell typed cervical neurinoma.

Adult↗

PubMed1991

Spinal cord herniation associated with an intradural spinal arachnoid cyst diagnosed by magnetic resonance imaging.

Two rare cases of spinal cord herniation associated with intradural spinal arachnoid cyst are reported. A preoperative magnetic resonance imaging scan demonstrated the presence of spinal cord herniation, identified as a protrusion continuous with the spinal cord. Surgery upon the intradural spinal arachnoid cyst improved progressive neurological dysfunction. The authors postulate that spinal cord herniation occurred for the following reason: The pressure of the intradural arachnoid cyst on the dorsal aspect of the spinal cord caused thinning of the dura, leading to a tear and, thus, the development of an extradural arachnoid cyst. Along with the enlargement of intradural arachnoid cyst, the spinal cord herniated through the tear in the dura into the extradural arachnoid cyst.

Adult↗

PubMed1991

[Post-traumatic syringomyelia. Report of three cases].

Three cases of post-traumatic syringomyelia are presented and the mechanism of syrinx formation is discussed. Two cases were examined radiologically. Computed tomography and magnetic resonance images (MRI) showed an expansive syrinx with adhesive arachnoiditis in the thoracic levels below the injury site and a localized syrinx on the posterolateral gray matter in the cervical levels above the injury site. These syrinxes existed below the C2 level and had no communication with the fourth ventricle. The other was an autopsy case. Postmortem examination revealed that a syrinx existed from C2 to Th6 and had no communication with the fourth ventricle or the central canal. It is concluded that small traumatic cavities in the gray matter evolve to an extensive syrinx by cerebrospinal fluid (CSF) entering via the posterior root entry zone, and adhesive arachnoiditis is an important factor in increasing the CSF which is entering. MRI was useful for the diagnosis.

Adult↗

PubMed1991

[Histological investigation on hydroxyapatite ceramics as materials of artificial bone grafts in the cervical spine].

UNLABELLED: The purpose of this study is to understand the utility of the hydroxyapatite (HA) ceramics as artificial bone graft substances in the cervical spine. METHOD: Dense and porous HA were implanted into the vertebral body and intervertebral space of the adult dog cervical spine and the implanted cervical bones were removed 4, 8 and 24 weeks after implantation and examined by contact microradiography (CMR), and histological observations of the non-decalcified material stained with Van Gieson's and decalcified material stained with hematoxylin and eosin. RESULTS AND CONCLUSION: 1. Sufficient formation of new bone with the bone marrow was recognized on the surface and in the pores of the porous HA being implanted to the cervical vertebra. 2. Dense HA was inadequate for the implantation into cervical areas because of its physical nature, such as glass-like smooth surface and the extreme hardness. 3. HA was not fit for usage in the intervertebral space of the cervical spine because of its total ineffectiveness in the functions such as the supporting heavy weight of the head and the mobility and its histologically poor activity of the new bone formation in the intervertebral space.

Animals↗

PubMed1991

[Usefulness of MRI in the diagnosis of spontaneous hematomyelia; a case of intramedullary cavernous hemangioma].

Recent improvement of MRI has enabled us to clearly visualize intramedullary spinal lesions which previously could not be recognized by CT scan or myelography. We reported a case of hematomyelia caused by intramedullary cavernous hemangioma. In this case, MRI was very useful in efforts to recognize the lesions. With the use of MRI, we will be able to accurately ascertain the location and characteristics of intramedullary spinal lesions. The number of surgically treated cases of idiopathic hematomyelia will increase in the future.

Hemangioma, Cavernous↗

PubMed1991

[Magnetic resonance imaging of posttraumatic syringomyelia and its surgical treatment].

Posttraumatic syringomyelia is an uncommon but significant late complication of spinal cord injury. It occurs in approximately 1.1 - 3.2% of cases of spinal injuries. With the increasing availability of CT and magnetic resonance imaging (MRI), the incidence of posttraumatic syringomyelia is increasing. The purpose of this report is to show MRI of posttraumatic syringomyelia and to assess the results of surgical treatment. Materials and Methods This series included 16 cases of posttraumatic syringomyelia studied with MRI. 9 out of 16 cases showed delayed deterioration of neurological symptoms following spinal injuries. The interval between the trauma and the delayed symptoms of deterioration was from 2 years 2 months to 32 years (mean, 8 years and 5 months). There were 13 men and 3 women. The age ranged from 22 to 69 years, with a mean age of 42 years. The initial spinal cord injury was located in the lower cervical region in 4 cases, the thoracic region in 8, and the upper lumbar region in 4. All the patients were studied with resistive 0.15T system (Toshiba MRT 15 A) or a superconductive 0.5T system (Toshiba MRT 50 A) or a superconductive 1.5T system (GE Sigma or Siemens Magnetom). Six patients underwent 8 operative procedures for posttraumatic syringomyelia. Syringoperitoneal shunt was performed in 4 patients, syringosubarachnoid shunt in 3 and ventriculoperitoneal shunt in one. Results 1. MRI In all cases, the posttraumatic syringomyelia was easily diagnosed by MRI. The syrinx extended superiorly and/or inferiorly from the area of the old trauma. In 4 out of 16 cases, the syrinx extended into the medulla oblongata.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

[Diagnosis and surgical treatment of spinal hemangioblastoma].

Spinal hemangioblastoma is a rare tumor. Its incidence varies from 1.6 to 2.1% of primary spinal cord tumors. In this report, the authors described MRI (magnetic resonance imaging) of spinal hemangioblastoma and its surgical results. [MATERIALS AND METHODS] This series included 10 spinal hemangioblastomas studied with CT or MRI. There were 8 men and 2 women. The age ranged from 21 to 68 years, with a mean age of 45 years. 6 patients were preoperatively and postoperatively studied with a resistive 0.15 T system (Toshiba MRT 15A) or a superconductive 1.5 T system (GE Signa or Siemens Magnetom). The lesions were single in 8 out of 10 patients and multiple in 2. 10 spinal hemangioblastomas were located in intramedullary space and 2 in both intramedullary and extramedullary space. 8 out of 10 patients (80%) were associated with cyst. [RESULTS] (1) MRI In T1-weighted MR images after administration of Gd-DTPA, the solid component of the tumor enhanced brilliantly. The enhanced lesions contained serpiginous areas of signal void, reflecting vascular structures in 5 out of 6 cases. The intrinsic spinal cord signal was heterogenous with low intensity areas representing the associated cyst. The cyst appeared either isointensive to cerebrospinal fluid (CSF) or hyperintense relative to CSF and slightly hypointense relative to the spinal cord. The precise delineation of the tumor was impossible without enhancement. Noncontrast T1-weighted MR images displayed diffuse widening of the spinal cord. On T2-weighted MR images, all regions of the spinal cord enlargement increased in signal. (2) Postoperative results All 10 cases of spinal hemangioblastomas were totally removed with good postoperative results and the associated cysts were drained. The postoperative MRI showed the disappearance of the tumor and significant reduction in the size of the cyst. [CONCLUSION] (1) Gd-DTPA enhanced MRI was useful in defining and outlining the solid component of spinal hemangioblastoma. (2) The complete removal of the tumor with only drainage of the cyst was possible with good postoperative results.

Adult↗

PubMed1991

[Stab wounds of the spinal cord by a kitchen knife: report of a case].

A case of spinal cord injury due to stab wounds by a kitchen knife is presented. A 41-year-old male was hospitalized because of spinal cord injury resulting from stab wounds inflicted with a kitchen knife in the posterior cervical area. Neurological examination on admission showed paraplegia, disappearance of deep tendon reflex in both lower extremities, sensory disturbance below T1 level, left Horner's syndrome and urinary disturbance. In addition to these symptoms cerebrospinal fluid was leaking from the wounds. An emergency operation was performed. After laminectomy of C7 and T1, we found that the spinal cord was almost completely split at C7/T1 level. Dural plasty was performed. Neurologically, sensory disturbance was slightly improved at 4 months after the injury. Initial MRI (TR: 200 msec, TE: 20 msec) revealed high intensity at C7/T1 level which was damaged by the kitchen knife. MRI 5 months after the injury revealed low intensity on T1 weighted imaged, high intensity on T2 and proton weighted image. The occurrence of the spinal cord injury due to stab wounds by a kitchen knife is very rare in Japan. MRI is useful in the diagnosis of stab wounds of the spinal cord.

Adult↗

PubMed1991

[A case report: intraspinal canal osteochondroma at the cervicothoracic junction causing spinal cord compression].

Osteochondromas are one of the most common benign tumors. They typically develop on long, tubular bones, only rarely compressing the spinal cord. We report the case of a 9-year-old boy who suffered paraparesis secondary to a cervical osteochondroma based at the vertebral body. The tumor was removed using laminectomy. CT scanning, plain X-ray films, and MR imaging were used in the preoperative assessment of the lesion and the operative method.

Child↗

PubMed1991

[A case of epidural lipomatosis presenting spinal ataxia].

A 41-year-old man was doing well until July 1989, when he noted numbness over soles, followed 4 months later by difficulty in walking. These symptoms were progressively getting worse, and he was admitted to our department on June 12, 1990. General physical examination was unremarkable. Neurologically cranial nerves were intact except old right, traumatic strabismus. Muscle tone and deep tendon reflexes were normal throughout, but bilateral Babinski and Chaddock reflexes were present. Mild weakness of lower extremities were found on muscle testing (4/5). In sensory system, superficial sensory disturbance below T10 was seen, and markedly diminished vibration and position senses of lower extremities were noted. Cerebellar test was intact, although unsteadiness was found on heel-shin test. Romberg sign was definitely positive. His gait was wide-based and ataxic. Laboratory data showed no abnormalities in CBC, chemistry, urinalysis, serological tests and endocrinological examinations. Spinal MRI (Siemens 1.5 Tesla) showed abnormal deposition of epidural fatty tissues compressing spinal cord with flattening of cord from T4 to T8. Spinal ataxia as compressive myelopathy due to epidural lipomatosis was considered and he underwent laminectomy from T4 to T8 with improvement in walking. Epidural lipomatosis is an unusual cause of spinal cord compression, presenting compressive myelopathy, radiculopathy, cauda equina syndrome, intermittent claudication, or back pain. Most of cases were associated with long-term administration of adrenocortical steroid hormone, or underlying diseases, except only 3 cases including ours. This is the first case of spinal epidural lipomatosis presenting progressive gait disturbance due to spinal ataxia.

Adult↗

PubMed1990

Syringo-subarachnoid shunt for syringomyelia associated with Chiari malformation (type 1).

The authors report the surgical results of 28 patients with syringomyelia associated with Chiari malformation (type 1). 28 patients underwent 34 operative procedures. Syringo-subarachnoid shunt was performed in 28 patients, foramen magnum decompression with syringo-subarachnoid shunt in three, ventriculo-peritoneal shunt in one, terminal syringostomy in one, and foramen magnum decompression with terminal syringostomy in one. In an average postoperative follow-up period of 3 years and 9 months ranging from one year to 7 years and one month, neurological symptoms and signs improved in 24 out of 28 patients (82%). Some improvement was noted in sensory deficit and motor weakness. In 3 patients, the symptoms did not change. In 3 patients whose symptoms were unchanged, preoperative studies demonstrated atrophy of the spinal cord, in which irreversible changes were shown. The symptoms deteriorated in one patient. In one patient whose symptoms increased 3 months after syringo-subarachnoid shunt, shunt insufficiency due to postoperative adhesive arachnoiditis was responsible for neurological deterioration. The authors propose that syringo-subarachnoid shunt is effective as a surgical procedure for syringomyelia associated with Chiari malformation (type 1) if the patient does not have symptoms due to Chiari malformation or has only mild signs and symptoms which do not require foramen magnum decompression, such as nystagmus or atrophy of sternocleidomastoid muscle.

Adolescent↗

PubMed1990

Hydrosyringomyelia associated with a Chiari I malformation in children and adolescents.

The clinical presentation, radiological features, and results of surgical treatment were analyzed in 17 cases of hydrosyringomyelia associated with a Chiari malformation, in children and adolescents younger than 20 years of age. The initial symptoms were a skeletal abnormality (71%), such as scoliosis (11 patients) or pes cavus (1 patient), pain or numbness (24%), and motor weakness (6%). Frequently seen signs on admission were sensory deficit (100%), scoliosis (85%), muscle weakness (64%), muscle atrophy (35%), and lower cranial nerve palsy (35%). The characteristic neurological findings were unilateral sensory and motor deficits (65%) with decreased or absent deep tendon reflexes on the same side. The localization of the syrinx on the axial section varied according to the level, even in the same patient. In 11 patients with unilateral sensory disturbances or unilateral sensory and motor deficits, the syrinx was located in the region corresponding to the posterolateral portion on the same side as that of sensory disturbance at the cervical or thoracic level. On the other hand, in 6 patients with bilateral sensory and motor deficits, the syrinx was located in the central portion and extended into the posterolateral portion of the more affected side. A syringosubarachnoid shunt was placed in 16 patients, foramen magnum decompression without closure of the obex was performed in 1 patient, ventriculoperitoneal shunt in 1 patient, terminal syringostomy in 1 patient, and foramen magnum decompression with terminal syringostomy in 1 patient. In 15 of 17 patients (88%), the neurological symptoms improved after an average follow-up of 4 years and 1 month. We think that as a surgical treatment, placement of a syringosubarachnoid shunt is effective.

Adolescent↗