Biomedical subjects

Takafumi Yayama

Publications and source records attributed to Takafumi Yayama.

12 recordsLinked to original sources

PubMed2006

Anterior versus posterior surgery for osteoporotic vertebral collapse with neurological deficit in the thoracolumbar spine.

Despite the increasing number of reports on surgical treatments for thoracolumbar osteoporotic vertebral collapse with neurological deficits, the choice of surgery remains controversial. In this retrospective study, we compared the outcomes of posterior and anterior surgeries for single-level osteoporotic vertebral collapse with neurological deficit in the thoracolumbar spine. Both posterior and anterior surgical approaches were performed with a consistent procedure for a single surgical indication at one institution. Twenty-four patients treated with posterior surgery and 28 patients treated with anterior surgery were followed-up over an average of 5 years after surgery. Radiographic results (kyphotic angle, bony fusion, and instrumentation failure), neurological improvement, and surgical complications were compared between the two groups. The average correction angle after surgery was larger in the posterior group than in the anterior group (P = 0.013), but not at final follow-up (P = 0.755). The average loss of correction was also higher in the posterior group than in the anterior group (P = 0.037). There was no significant difference in neurological outcomes between anterior and posterior approaches (P = 0.080). Two-way analysis of variance (ANOVA) showed that the neurological outcome was better in wedge type than in flat type vertebral collapse, regardless of the type of surgical approach (P = 0.0093). In wedge type vertebral collapse, neurological improvement tended to be greater after anterior than after posterior surgery. In four of six cases with instrumentation failure in the anterior group, a titanium cage subsided more than 5 mm but bony fusion was eventually achieved without causing neurological problems. In the posterior group, six cases experienced instrumentation failure during the postoperative course (two cases with screws loosened from pedicles and bodies, and one case with breakage of a screw neck). None of the patients developed instrumentation-related neurological problems. Two cases in each group developed pseudoarthrosis. In single-level osteoporotic vertebral collapse with neurological deficit, anterior surgery tended to improve neurological deficit in wedge type, but not in flat type collapse, compared with posterior surgery.

Aged↗

PubMed2006

Effects of disease severity on response to lateral wedged shoe insole for medial compartment knee osteoarthritis.

OBJECTIVE: To determine the effects of lateral wedged insoles on knee kinetics and kinematics during walking, according to radiographic severity of medial compartment knee osteoarthritis (OA). DESIGN: A prospective case control study of patients with medial compartment OA of the knee. SETTING: Gait analysis laboratory in a university hospital. PARTICIPANTS: Forty-six medial compartment knees with OA of 23 patients with bilateral disease and 38 knees of 19 age-matched healthy subjects as controls. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: We measured the peak external adduction moment at the knee during the stance phase of gait and the first acceleration peak after heel strike at the lateral side of the femoral condyles. Kellgren and Lawrence grading system was used for radiographic assessment of OA severity. RESULTS: The mean value of peak external adduction moment of the knee was higher in OA knees than the control. Application of lateral wedged insoles significantly reduced the peak external adduction moment in Kellgren-Lawrence grades I and II knee OA patients. The first acceleration peak value after heel strike in these patients was relatively high compared with the control. Application of lateral wedged insoles significantly reduced the first acceleration peak in Kellgren-Lawrence grades I and II knee OA patients. CONCLUSIONS: The kinetic and kinematic effects of wearing of lateral wedged insoles were significant in Kellgren-Lawrence grades I and II knee OA. The results support the recommendation of use of lateral wedged insoles for patients with early and mild knee OA.

Aged↗

PubMed2006

Effect of compensation procedures for velocity on repeatability and variability of gait parameters in normal subjects.

UNLABELLED: OBJECTIVE To evaluate the effects of a mathematical procedure that adjusts for gait velocity on the variability seen in gait analysis. DESIGN: Evaluation before and after compensation. SETTING: Gait laboratory, Fukui University Hospital, Japan. SUBJECTS: Fourteen normal volunteers. OUTCOME MEASURES: A computerized gait analysis system with two forceplates and a light source spot measuring device was used. Gait measurement in each subject was performed on three different days. RESULTS: The gait parameters measured on three different days were significantly different, particularly step length, stride length, velocity, the components of floor-reaction forces and hip motion. In these parameters, intraclass correlation coefficient, ICC (1,1) was not high (range 0.05-0.71). However, there was a high correlation between these parameters and velocity and high repeatability was obtained following compensation for velocity (ICC (1,1), range 0.73-0.97). In contrast, compensation of parameters whose measurement was not significantly different before compensation did not improve ICC (1,1). Variability of all parameters was acceptable, however CV (an index of variability) improved significantly after compensation compared with that before compensation in six of 15 parameters. CONCLUSIONS: Our findings suggest that low repeatability in gait parameters should be considered even when the gait of normal subjects is measured on different days. A high repeatability and more acceptable variability were obtained when the data were compensated for velocity.

Analysis of Variance↗

PubMed2006

Anterior expandable strut cage replacement for osteoporotic thoracolumbar vertebral collapse.

OBJECT: The authors investigated the usefulness of using an expandable cage strut in anterior reconstruction after osteoporotic vertebral collapse in patients with neurological deficits. METHODS: Twenty-eight patients who had undergone expandable cage strut-augmented anterior thoracolumbar reconstruction participated in a follow-up review for a mean of 4.9 years. Radiographs were reviewed for kyphosis, lateral tilt of the implant, cage subsidence, the presence of a solid fusion mass, and instrumentation failure. Changes in neurological status and visual analog scale (VAS) pain score, as well as technique-related complications, were examined. The mean angles +/- the standard deviations of kyphosis correction 4 to 6 weeks after surgery and at final follow-up examination were 10.4 +/- 7.6 degrees and 5.6 +/- 6.0 degrees, respectively. The mean subsidence of the expandable cage within the adjacent vertebrae was 2.5 +/- 3.0 mm at the final follow-up examination. Neurological improvement at the final follow up was more significant in patients with Type I (wedge-type) than Type 2 (flat-type) (p = 0.037) or Type 3 (concave-type) (p = 0.006) vertebral collapse. Follow-up VAS scores were significantly higher in patients with Type 1 than Type 3 collapse (p = 0.012). In all cases the authors observed solid union with incorporation of the cage. There were no surgery-related complications. CONCLUSIONS: An expandable titanium cage strut seems useful in vertebral body replacement in patients with osteoporotic thoracolumbar collapse. Favorable results were obtained in cases of Type I collapse (wedge type) in which the middle and posterior columns remained comparatively intact.

Aged↗

PubMed2005

Targeted retrograde gene delivery into the injured cervical spinal cord using recombinant adenovirus vector.

Direct routes of gene administration (intrathecal, intracerebroventricular or intraparenchymal infusion) have been used for effective and sustained gene delivery, but serious concerns exist about possible traumatic injury as well as neural damage that may lead to further tissue necrosis, apoptosis and cell death. We evaluated targeted retrograde gene delivery through the sternomastoid muscle (innervated by the spinal accessory nerves) into the injured cervical spinal cord using a recombinant adenovirus vector. LacZ gene expression in the cervical spinal cord was noted from 3 days to 4 weeks after the injection of vector into the sternomastoid muscles of the rats. Recombinant adenovirus vector was transferred via a retrograde mechanism into the injured cervical spinal cord with high transduction efficacy (80.6--98.9%) over certain adenoviral titer and dosage. Transduction was less efficient when the vector was injected 1 and 2 weeks after spinal cord injury (44.2--56.8%). Our results indicate retrograde delivery of recombinant adenovirus vector is possible immediately after spinal cord injury, and that this method is promising for gene delivery because it is effective, selective, less invasive to the injured spinal cord, has long-lasting gene expression, and is potentially feasible treatment choice for spinal cord injury.

Adenoviridae↗

PubMed2005

Localization and changes of intraneural inflammatory cytokines and inducible-nitric oxide induced by mechanical compression.

STUDY DESIGN: Investigation of intraneural inflammation induced by mechanical compression. OBJECTIVES: In order to investigate the mechanism of neuropathy, this study used a median nerve compression model in dogs. Immunohistochemistry was used to examine the localization and changes of inflammatory cytokines and nitric oxide (NO). SUMMARY OF BACKGROUND DATA: The manifestation of pain at sites of inflammation has a close relationship with the release of mediators from macrophages such as interleulin-1 (IL-1) and tumor necrosis factor-alpha (TNF-alpha), as well as with NO. However, the mediators involved in inflammation of nerve due to mechanical compression remain almost unknown. METHODS: In this study, the median nerve of dogs was compressed with a clip for three weeks to observe the changes caused by compression. Immunohistochemistry was done by the avidin-biotin-peroxidase complex method to observe the changes of T cells (CD45) and macrophages (Mac-1) after compression. Antibodies against IL-1beta, TNF-alpha, and inducible nitric oxide synthesis (i-NOS) were used to examine the localization and changes of these mediators caused by nerve compression. RESULTS: In control animals, resident T cells were detected, but there were no macrophages. IL-1beta was positive in the Schwann cells and vascular endothelial cells. However, no cells showed TNF-alpha or i-NOS positively. After nerve compression, numerous T cells and macrophages appeared among the demyelinized nerve fibers. The macrophages were positive for IL-1beta, TNF-alpha and i-NOS. CONCLUSION: Inflammatory cytokines and NO may be involved in intraneural inflammatory changes arising from mechanical compression. Such mediators may be of importance in the manifestation of neuropathy.

Animals↗

PubMed2005

Effect of lumbar nerve root compression on primary sensory neurons and their central branches: changes in the nociceptive neuropeptides substance P and somatostatin.

STUDY DESIGN: This study examined the effect of lumbar nerve root compression on nociceptive neuropeptides in the axonal flow using an in vivo model. OBJECTIVES: The aim was to investigate changes in axonal flow after nerve root compression by using immunohistochemical techniques to detect substance P (SP) and somatostatin (SOM), which is thought to be involved in temperature and pain sensation. SUMMARY OF BACKGROUND DATA: Disturbance of intraradicular blood flow and nerve fiber deformation caused by mechanical compression are thought to be involved in the pathophysiology of diseases characterized by radicular symptoms, such as lumbar disc herniation and lumbar canal stenosis. However, little research has been conducted into the changes of axonal flow associated with nerve root compression. METHODS: In dogs, the lumbar nerve roots were compressed using four types of clips with different pressures. Changes of SP and SOM levels in the spinal dorsal horn, dorsal root, and dorsal root ganglions were examined immunohistochemically after compression for 24 hours or 1 week. RESULTS: After compression for 24 hours, axonal flow in the dorsal root was impaired, accumulation of SP and SOM was observed distal to the site of compression, and there was a decrease in the number of dorsal root ganglion cells showing positively for these neurotransmitters. Compression for 1 week resulted in a decrease in the number of SP- and SOM-positive fibers in the spinal dorsal horn. CONCLUSION: Change of axonal flow resulting from direct nerve compression could affect the metabolism of neurotransmitters that flow inside the axons and may be a primary cause of the decline in nerve function.

Animals↗

PubMed2005

Multivariate analysis of the neurological outcome of surgery for cervical compressive myelopathy.

BACKGROUND: The neurological outcome of decompressive surgery for cervical myelopathy is influenced by several factors. Although each factor may have an independent effect, it is more likely that the outcome is influenced by more than one factor. We examined the results of multivariate analysis and multiple regression analysis of the neurological outcome of patients treated by cervical cord decompression. METHODS: A total of 77 patients with cervical spondylotic myelopathy (43 men, 34 women) and 58 with ossification of the posterior longitudinal ligament (OPLL) (39 men, 19 women) were studied with an average follow-up interval of 8.3 years. The clinical data, neurological and radiological findings, and results of spinal cord evoked potentials (SCEPs) were retrieved from the medical records and included in the analysis. RESULTS: Multivariate analysis indicated that the outcome for patients with spondylosis was positively influenced, in order of importance, by increased transverse area of the cord >or=60%, presence of single-level anterior fusion, a high preoperative neurological score, normal epidural SCEPs, and clinical features of brachialgia and cord type. In patients with OPLL, multivariate analysis showed that the long-term outcome was positively influenced, in order of importance, by the presence of mixed or localized OPLL, normal epidural SCEPs, high preoperative neurological score, a single-vertebra spondylectomy with anterior fusion, laminoplasty, widening of the transverse area of the cord >or=40%, and an expansion rate of the spinal canal after laminoplasty >or=40%. CONCLUSIONS: We suggest that multivariate analysis is useful for assessing the neurosurgical outcome in patients with cervical compressive myelopathy.

Adult↗

PubMed2005

Dynamic analysis of the resultant force acting on the hip joint during level walking.

The present study was designed to determine the resultant force acting on the hip joint during walking using a new dynamic analysis method. Our model utilized joint motion, ground reaction force, and muscle strength data from 18 women (6 normal women aged 20-24 years, 6 normal women aged 50-57 years, and 6 female patients with osteoarthritis, aged 50-66 years). We analyzed the resultant force using the multibody dynamic analysis system. To determine the factors that influence the force acting on the hip, we examined the effect of age and total hip arthroplasty. The maximum resultant force acting on the femoral head was dependent on the subject body weight and correlated with muscle strength and walking speed. The results of this study highlight the agreement between computer simulation analysis and actual measurement of the resultant force acting on the hip. Our results suggest that muscle strength and walking speed are significant determinants of the resultant force acting on the hip.

Adult↗

PubMed2005

[Blood circulation of cauda equina and nerve root].

It is generally considered that the genesis of radiculopathy associated with pathologic conditions of the spine, such as lumbar disc herniaton and lumbarl canal stenosis, may result from both mechanical compression and vascular problems. In this article, we have reviewed about the blood circulation of cauda equina and nerve root under normal and pathologic conditions.

Adult↗

PubMed2004

Metabolic neuroimaging of the cervical spinal cord in patients with compressive myelopathy: a high-resolution positron emission tomography study.

OBJECT: The authors conducted a study to examine whether high-resolution [18F]fluorodeoxyglucose (FDG)-positron emission tomography (PET) could be used to visualize deterioration of cervical spinal cord function associated with various degrees of compression and to determine its potential usefulness during assessment of compressive myelopathy. METHODS: In 23 patients requiring decompressive surgery for myelopathy FDG-PET was performed. The preoperative findings of high-resolution FDG-PET were compared with the neurological scores and magnetic resonance (MR) imaging findings. The preoperative standardized uptake value (SUV) of FDG utilization rate of the cervical cord correlated with the pre- (r = 0.497, p = 0.016) and postoperative neurological scores (r = 0.595, p = 0.003), as well as with the rate of neurological improvement postoperatively (r = 0.538, p = 0.008). The FDG utilization rate did not correlate with the high signal intensity on T2-weighted MR images. CONCLUSIONS: Analysis of these results indicates that high-resolution FDG-PET imaging provides useful qualitative and quantitative estimates of impaired metabolic activity of the compromised cervical cord that correlate closely with the severity of neurological dysfunction.

Adult↗

PubMed2003

Lumbar epidural abscess causing septic shock: case report.

This case report describes a lumbar epidural abscess that caused septic shock. A 48-year-old woman who developed a high temperature was diagnosed as having a respiratory tract infection. She became unconscious the next day and was transferred to the intensive care unit for monitoring and treatment. She complained of increasing lower back pain as consciousness improved. Magnetic resonance images of the lumbar spine showed an abscess shadow between the vertebral body and dura mater at the level of L3-S1. Surgical drainage of the epidural abscess was performed as an emergency procedure, and the patient recovered immediately. The primary source of the epidural abscess was probably the respiratory tract infection, which spread to the epidural space through hematogenous dissemination. The initial treatment of the epidural abscess was rest and antibiotics, but surgical treatment was needed to save the patient because of septic shock.

Bronchitis↗