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Biomedical subjects

K Yonenobu

Publications and source records attributed to K Yonenobu.

At least 73 records · Page 4Linked to original sources
PubMed1989

Unstable cervical spine in athetoid cerebral palsy.

The manifestations and pathomechanism of cervical instability of the athetoid neck in cerebral palsy (CP) patients was clarified in this study by means of static and dynamic x-ray analysis. Instability was defined as follows: 1) listhesis indicating anterior or posterior slip of more than 3 mm and/or 2) sagittal rotation between two vertebrae beyond the normal range measured by Penning. Cervical instability fitting this definition mainly took place in the upper and middle cervical disc levels, such as C3-4, C4-5, and/or occasionally C5-6. These coincide with the disc levels adjacent to the apex of the lordotic curve and/or those around the transitional vertebrae between the two reversed curves that render the cervical spine S-shaped in athetoid CP. A large facet angle at the apex vertebra facilitated anterior and/or posterior listhesis of the vertebrae. Conversely, a sudden decrease in the facet angle around the transitional vertebra in S-shaped curves precipitated deflection of the spine and increased sagittal rotation at this level. In addition to these structural abnormalities, rapid and repetitious neck movements seemed to accelerate the progression of cervical instability in athetoid CP patients.

Athetosis↗
PubMed1989

The prognosis of surgery for cervical compression myelopathy. An analysis of the factors involved.

We have studied the morphometry of the spinal cord in 50 patients with cervical compression myelopathy. Computed tomographic myelography (CTM) showed that the transverse area of the cord at the site of maximum compression correlated significantly with the results of surgery. In most patients with less than 30 mm2 of spinal cord area, the results were poor; the cord was unable to survive. Several factors, such as chronicity of disease, age at surgery and multiplicity of involvement are said to influence the results of surgery, but the transverse area of the cord at the level of maximum compression provides the most reliable and comprehensive parameter for their prediction.

Adult↗
PubMed1988

Myelopathy hand characterized by muscle wasting. A different type of myelopathy hand in patients with cervical spondylosis.

While the authors have often observed the hand presenting spastic dysfunction and deficient pain sensation in patients with cervical compression myelopathy, which has been termed "Myelopathy hand," they have occasionally seen a different type of myelopathy hand characterized by muscle wasting and motor dysfunction in patients with cervical spondylosis. This type of myelopathy hand they have termed "amyotrophic type of myelopathy hand." Because it is similar to the hand of a patient suffering from motor neuron disease, and yet is treatable, the authors thought it worthwhile to report this type of hand in detail. The main clinical features are localized wasting and weakness of the extrinsic and intrinsic hand muscles, but not accompanied by either sensory loss or spastic quadriparesis. For an accurate diagnosis, attention should be paid to the narrow anteroposterior (AP) canal diameter of the cervical spine (less than 13mm), multisegmental spondylosis in C5-6 and C6-7 disc levels and a reduced transectional area of the spinal cord at the C7, C8, or T1 spinal cord segments. To date the authors have seen 15 patients with this hand; seven underwent either spondylectomy or laminoplasty. In six patients who were satisfied with surgical results, recovery from muscle wasting and weakness was seen.

Electromyography↗
PubMed1988

Prosthetic replacement surgery for cervical spine metastasis.

Since 1972, 18 patients suffering from metastatic cancer in the cervical spine were treated with prosthetic replacement surgery. The surgery enabled the authors to decompress the spinal cord and the nerve roots and at the same time restore stability in the affected spine. Patients suffering from severe pain and spinal cord and/or nerve root compression secondary to involvement of a single vertebral body particularly benefited from this surgery. The rates of positive recovery were as follows: 94.1% for pain relief, 91.7% for motor recovery, and 87.5% for ambulation. The surgical efficacy was maintained until the terminal stage. Tumor recurrence took place in five cases--two anterior, and three posterior. Anterior recurrence caused a marked instability, whereas posterior recurrence did not affect stability.

Cervical Vertebrae↗
PubMed1988

Morphometry of the cervical spinal cord and its relation to pathology in cases with compression myelopathy.

The purpose of this study was to determine whether or not computerized tomography myelography (CTM) gave an actual size and shape of the cervical spinal cord, and whether such dimensions reflected pathology of the spinal cord in cases suffering from compression myelopathy. Spinal cord transverse area and compression ratio (sagittal diameter divided by transverse diameter) were measured as indicators of spinal cord morphology. As a basis for this study, we first performed CTM of cadaveric cervical columns and compared the actual dimensions of the spinal cord of the cadaveric specimens with the CTM image. Second, the correlations between these dimensions and pathology of the affected spinal cord were investigated. The results showed that CTM provided a precise image of the actual cross-section of the spinal cord. In 12 cadaveric specimens of cervical myelopathy examined, the transverse area and compression ratio were in good correlation with the severity of observed pathological changes.

Aged↗
PubMed1988

Desmoplastic fibroma of the axis. A case report.

Desmoplastic fibroma of the bone appears in a wide variety of bones but rarely involves the spine. A 24-year-old male with desmoplastic fibroma of the axis treated by complete resection and posterior spinal fusion is reported. There was no recurrence of the tumor three years after surgery. Complete resection and reconstructive surgery for spinal instability are recommended for this benign spinal tumor.

Adult↗
PubMed1987

Myelopathy hand. New clinical signs of cervical cord damage.

A characteristic dysfunction of the hand has been observed in various cervical spinal disorders when there is involvement of the spinal cord. There is loss of power of adduction and extension of the ulnar two or three fingers and an inability to grip and release rapidly with these fingers. These changes have been termed "myelopathy hand" and appear to be due to pyramidal tract involvement. The characteristic nature of the signs permit the distinction between myelopathy and changes due to nerve root or peripheral nerve disorder. The clinical significance of these signs has been assessed against other tests and their value in management is discussed.

Fingers↗
PubMed1987

Thoracic myelopathy secondary to ossification of the spinal ligament.

The authors describe their experience with 26 cases of thoracic myelopathy secondary to hypertrophic ossification of the spinal ligament (posterior longitudinal ligament and/or ligamentum flavum). The clinical manifestations of this condition and results of its surgical treatment are described. The commonest symptoms were numbness or tingling in the legs and feet and gait disturbance. Most of the patients with involvement of the upper thoracic spine showed typical features of thoracic myelopathy: that is, sensory and motor deficits in both the trunk and lower extremities, sphincter disturbance, and exaggerated tendon reflexes. Several patients with involvement of the thoracolumbar junction presented with atypical symptoms of thoracic myelopathy and were sometimes misdiagnosed and treated inappropriately. Surgical treatment, particularly laminectomy, was not always successful. Inconsistencies in the surgical outcome were caused by either operative complications or reversal of the initial improvement during the follow-up period. The results of anterior surgery for the condition were more favorable; however, use of this procedure was rarely indicated.

Adult↗
PubMed1987

Cervical radiculopathy or myelopathy secondary to athetoid cerebral palsy.

Radiculopathy or myelopathy often occurs during adult life in patients who have athetosis. Herniation of an intervertebral disc, spondylosis, malalignment or instability of the cervical spine, or a combination of these lesions, can develop because of the athetoid hyperactivity. We reviewed the cases of ten patients who had cervical radiculopathy or myelopathy, or both, secondary to athetosis and who were surgically treated between the ages of thirty and fifty-eight years. The surgery consisted of discectomy, removal of osteophytes, and anterior interbody fusion. When several segments were involved, an extensive subtotal resection of the vertebrae and discs, followed by strut bone-grafting, was done.

Adult↗
PubMed1986

Elongation of brachymetatarsy with ceramic implant: a roentgenographic evaluation of its utility.

The metatarsal bone was elongated by intercalary implantation of a single-crystal alumina ceramic in 7 patients with brachymetatarsy. The implants were encased with new bone 24 months after surgery and resulted in 5.2 to 9.2 mm elongation of the metatarsal bone. The response of the bone to the ceramic implant was observed roentgenographically. No resorption or pseudoarthrosis of the bones, nor loosening or breakage of the implants, were observed. The alumina ceramic implant proved to be a useful substitute for a bone graft, because of its biocompatibility and strength.

Adolescent↗
PubMed1986

Causes of neurologic deterioration following surgical treatment of cervical myelopathy.

Neurologic deterioration was analyzed in 110 patients with surgically treated cervical myelopathy secondary to soft disc hernia or spondylosis. Follow-up periods ranged from 2 to 14 years, with an average of 6 years. Of 110 patients, 29 suffered neurologic deterioration. In most of the patients, deterioration occurred within the first year after surgery. Causes of deterioration were divided into three categories: direct trauma to neural tissue during surgery (a preventable complication); instability of the spine, progression of spondylotic changes above or below the level of fusion, and non-union (apparently unpreventable but treatable); and nonsurgery-related accidental trauma (unavoidable and often irreversible). Countermeasures for the deterioration are discussed.

Cervical Vertebrae↗
PubMed1986

Interspinous wiring without bone grafting for nonunion or delayed union following anterior spinal fusion of the cervical spine.

Nine patients who had unsuccessful anterior interbody fusion or subtotal spondylectomy and fusion for cervical spondylosis were treated by interspinous wiring without bone grafting. Bone union was confirmed during a mean postoperative period of 2 years and 2 months in seven patients by the disappearance of clear zones observed preoperatively in the disc space, and by continuity of the trabeculae in radiograms. One of the two patients in whom the procedure failed to unite the site of nonunion had received technically inadequate wiring with slight mobility at the wiring site; in the other patient, the grafted bone had collapsed and no sclerotic shadow of the nonunion site was seen at the time of surgery. Both patients underwent wiring after considerable intervals from the time of the initial anterior spinal fusion. We found that satisfactory bone union can be obtained for nonunion or delayed union following anterior cervical spinal fusion by interspinous wiring without further bone grafting if applied to properly selected patients.

Adult↗
PubMed1985

Choice of surgical treatment for multisegmental cervical spondylotic myelopathy.

Three surgical procedures for multisegmental cervical spondylotic myelopathy were evaluated on the basis of a follow-up study (12-157 months) of 95 patients. Twenty-four patients were treated by extensive laminectomy, 50 by anterior interbody fusion by the Cloward and/or Smith-Robinson techniques, and 21 by subtotal spondylectomy and fusion. Results of subtotal spondylectomy were significantly (P less than 0.01) better when compared with those of the other two procedures. It was concluded that spondylosis up to three disc levels should be treated by subtotal spondylectomy and fusion regardless of the canal diameter. When involvement extended four or more levels, extensive laminectomy was recommended.

Cervical Vertebrae↗
PubMed1985

Atlantoaxial rotatory fixation. Radiographic study of its mechanism.

The mechanism of atlantoaxial rotatory fixation was investigated by means of CT scanning. During the acute stage, there was a common rotatory displacement of the occiput and atlas complex in relation to the axis. As symptom subsided spontaneously or with treatment, the displacement was reduced and the occiput and atlas complex was in normal alignment with the axis. In a few cases where survey x-ray presented persistence of a typical displacement between C1/2, there was a persistent rotatory displacement of the atlas within the occiput-atlas-axis (C0-C1-C2) complex. Here, the occiput faced in nearly the same direction as the axis and the rest of the cervical spine. This meant an interlocking of the rotated atlas between C0 and C2. Either one of the lateral mass articulation of the rotated atlas was anteriorly dislocated and interlocked. Compensatory derotation of the occiput and a hypermobility of the C0/1 articulation, limited to younger children, presumably produced such a rotatory displacement of the atlas within the C0-C1-C2 complex. Restriction of rotation and a residual postural deformity resulted from unilateral dislocation of the lateral mass articulation between C1/2 and residual rotatory displacement between C0/2, respectively. Difficulty in reducing such a postural deformity can be attributed to the fact that any manipulative force often fails to unlock the atlas within C0-C1-C2 complex because of an excessive mobility between the C0/C1, and a ligamentocapsular contracture can be established in the lateral mass articulation of the interlocked atlas in an ignored case.

Adolescent↗
PubMed1984

Ulnar ray deficiency: its various manifestations.

Eighty-eight upper extremities of 65 patients with ulnar ray deficiency were reviewed with regard to clinical manifestations. Based on the findings, a subclassification into four types was established: type I, hypoplasia or partial defect of the ulna; type II, total defect of the ulna; type III, total or partial defect of the ulna with humeroradial synostosis; and type IV, ulnar defect with congenital amputation at the wrist. Various manifestations of deficiency were evident not only within the ulnar ray but also in other rays. Hypoplasia of the shoulder and/or proximal part of the humerus was present in some cases of types III and IV. Elbow involvement varied from functioning (type I) to acute flexion contracture (type II) to fusion (type III). In 57 hands the digits and carpal bones in the radial ray showed hypoplasia and/or defect. Central digits and carpal bones were also influenced by ulnar ray deficiency, presenting carpal bone fusion, syndactyly, and delta phalanx.

Abnormalities, Multiple↗
PubMed1984

Congenital constriction band syndrome.

Eighty-three patients with congenital constriction band syndrome were reviewed. Clinical manifestations and associated anomalies were analyzed with attention directed to distribution of the involvement. Constriction bands, amputation, and acrosyndactyly were the main clinical manifestations of this syndrome. Involvement of the distal portions of the extremity was most common. In the hand, the central digits were involved most frequently, and the thumb was only minimally affected in most cases. Of the 19 cases with an associated clubfoot deformity, 10 were proven to be a paralytic clubfoot due to compression neuropathy of the peroneal nerve caused by a deep constriction band below the knee, whereas 9 had a normal peripheral nerve.

Amniotic Band Syndrome↗