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Biomedical subjects

Yoichi Shimada

Publications and source records attributed to Yoichi Shimada.

At least 19 recordsLinked to original sources
PubMed2007

Insufficiency fracture of the sternum simulating myocardial infarction: case report and review of the literature.

Insufficiency fracture is a type of stress fracture that occurs when stress is applied to the bone with less than the normal elastic resistance, as in osteoporosis. Insufficiency fracture of the sternum is rare among all kinds of fractures. We describe two cases with insufficiency fractures of the sternum secondary to osteoporosis and thoracic kyphotic deformity. Both of the present cases, a 76-year-old woman and a 65-year-old woman, presented with severe anterior chest pain simulating myocardial infarction. However, cardiopulmonary examinations including chest radiographs, electrocardiograms, and laboratory tests were normal. Lateral radiographs of the sternum in both patients showed insufficiency fractures of the sternum. Conservative treatment with rib bandaging/bracing and analgesics relieved their symptoms. Clinical behavior, type of sternal insufficiency fractures, and mechanism of the fracture are reviewed from perusal of the literature. We emphasize that sternal insufficiency fracture should be considered in the differential diagnosis of acute chest pain in the elderly along with myocardial infarction or pulmonary embolism.

Aged↗
PubMed2006

Effect of rotator interval closure on glenohumeral stability and motion: a cadaveric study.

The effect of rotator interval closure, which is performed as an adjunct to arthroscopic stabilization of the shoulder, has not been clarified. Fourteen fresh-frozen cadaveric shoulders were used. The position of the humeral head was measured using an electromagnetic tracking device with the capsule intact, sectioned, and imbricated between the superior glenohumeral ligament and the subscapularis tendon (SGHL/SSC closure) or between the superior and middle glenohumeral ligaments (SGHL/MGHL closure). The direction of translational loads (10, 20, and 30 N) and arm positions were (1) anterior, posterior, and inferior loads in adduction; (2) anterior load in abduction/external rotation in the scapular plane; and (3) anterior load in abduction/external rotation in the coronal plane. The range of motion was measured using a goniometer under a constant force. Both methods reduced anterior translation in adduction. Only SGHL/MGHL closure reduced anterior translation in abduction/external rotation in the scapular plane and posterior translation in adduction. Both methods reduced the range of external rotation and horizontal abduction. Rotator interval closure is expected to reduce remnant anterior/posterior instability and thereby improve the clinical outcomes of arthroscopic stabilization procedures.

Adult↗
PubMed2006

The effect of the inferior capsular shift on shoulder intra-articular pressure: a cadaveric study.

BACKGROUND: The inferior capsular shift procedure is commonly performed for multidirectional instability of the shoulder with excellent clinical results. HYPOTHESIS: The mechanism of this procedure is to increase shoulder stability by changing the responsiveness of intra-articular pressure to downward loading. STUDY DESIGN: Controlled laboratory study. METHODS: In 7 fresh-frozen cadaveric shoulders, inferior capsular shift was simulated by imbricating the anterior and posterior capsule using clamps. The position was monitored using an electromagnetic tracking device with the glenohumeral joint capsule intact, imbricated anteriorly, or imbricated anteriorly and posteriorly and with the inferior load of 0, 0.5, or 1.0 kg. Simultaneously, intra-articular pressure was monitored using a pressure transducer. Saline was injected into the glenohumeral joint to measure capsular volume. The capsule was vented, and the position was again measured. RESULTS: Intra-articular pressure was -71 +/- 19, -221 +/- 70, and -366 +/- 73 cm H(2)O with 0, 0.5, and 1.0 kg of load, respectively, with the capsule intact. With anterior imbrication, intra-articular pressure decreased to -79 +/- 10, -274 +/- 103, and -460 +/- 135 cm H(2)O, respectively, and with anterior and posterior imbrication, intra-articular pressure further decreased to -87 +/- 16, -308 +/- 74, and -548 +/- 39 cm H(2)O, respectively. The volume of the intact shoulder (36 +/- 9 mL) significantly decreased to 27 +/- 7 mL (75%) with anterior imbrication and to 15 +/- 5 mL (42%) with anterior and posterior imbrications (P = .0001). Before venting the capsule, inferior displacement was 5% of the vertical length of the glenoid, even with 1.0 kg of load with any capsular conditions. After venting, the humeral head dislocated inferiorly in all shoulders, even after imbrications. CONCLUSION: The inferior capsular shift procedure decreases joint volume and increases responsiveness of intra-articular pressure to downward loading. CLINICAL RELEVANCE: Biomechanical data provide scientific background to the commonly performed procedures of inferior capsular shift and thermal capsular shrinkage.

Adult↗
PubMed2006

Effects of alfacalcidol alone or in combination with elcatonin on incidence of osteoporotic vertebral fractures in postmenopausal women with spondylosis.

Osteoporosis and spondylosis often occur simultaneously. However, there are no previous reports about the effects of osteoporosis medication on incidence of vertebral fractures in people with spondylosis. In this study, we conducted a retrospective investigation of the effects of alfacalcidol alone or in combination with elcatonin on incidence of osteoporotic vertebral fractures in women with spondylosis. The present subjects were 101 postmenopausal women with osteoporosis aged >60 years, divided into three groups: D group (n = 45), treated for >5 years with alfacalcidol; D+ECT group (n = 26), treated for >5 years with alfacalcidol plus elcatonin; control group (n = 30), who received no medications for >5 years. Over the 5-year treatment period, bone mineral density (BMD) of the lumbar spine and proximal femur did not significantly change in the D and D+ECT groups, but they significantly decreased in the control group (P < 0.05). The number of incident vertebral fractures per patient was significantly higher in the control group (2.9) than in the D group (1.2) and D+ECT group (1.5) (P < 0.01). There was no significant difference in BMD or incident vertebral fractures between the D and D+ECT groups. In all three groups, the number of incident vertebral fractures positively correlated with the number of prevalent vertebral fractures (0.303 </= r </= 0.434), and negatively correlated with baseline BMD (-0.703 </= r </= -0.326) and the osteophyte score representing the degree of spondylosis (-0.769 </= r </= -0.365). Further multiple regression analysis revealed that the medication (D or D+ECT, P < 0.001) and the osteophyte score (P < 0.001) were the most significant contributors for the number of incident vertebral fractures. In conclusion, elcatonin had no additive effects on BMD or prevention of vertebral fractures in postmenopausal women receiving alfacalcidol. Presence of spondylosis (indicated by a high osteophyte score) appears to have an effect on prevention of vertebral fractures.

Aged↗
PubMed2006

Dural substitute with polyglycolic acid mesh and fibrin glue for dural repair: technical note and preliminary results.

BACKGROUND: An ideal dural substitute that enables watertight closure, has sufficient strength, and can be absorbed without remnant materials that induce inflammation, adhesion, and infection is not available. The purpose of this study was to evaluate the efficacy of a bioabsorbable polyglycolic acid (PGA) mesh and fibrin glue as a substitute for dural repair. METHODS: Altogether, 10 patients with noted dural tears during extradural spinal surgery and 20 patients who underwent durotomy for intradural spinal surgery were included in this study. In a series of 20 consecutive cases, dural closure was performed by suture and fibrin glue. In the subsequent 10 consecutive patients, dural closure was performed by suture and fibrin glue with the use of absorbable PGA mesh. The medical records and magnetic resonance imaging (MRI) of the surgical site were retrospectively reviewed to evaluate the presence of a cerebrospinal fluid (CSF) fistula or leakage after the surgery. RESULTS: A CSF fistula occurred in five patients who underwent dural repair with fibrin glue alone, and postoperative MRI showed CSF leakage in two patients with incidental dural tears after laminectomy for ossification of ligamentum flavum. No CSF fistula was present in patients who underwent dural repair using PGA mesh and fibrin glue, and no adverse effects or complications were encountered postoperatively. Follow-up MRI revealed no evidence of CSF leakage around the reconstructed dura mater. CONCLUSIONS: The use of PGA mesh and fibrin glue for the repair of dura mater is a useful method of preventing CSF leakage in spinal surgery.

Adolescent↗
PubMed2006

Low-dose intravenous ketamine potentiates epidural analgesia after thoracotomy.

BACKGROUND: Ketamine potentiates intravenous or epidural morphine analgesia. The authors hypothesized that very-low-dose ketamine infusion reduces acute and long-term postthoracotomy pain. METHODS: Forty-nine patients scheduled to undergo open thoracotomy were randomly assigned to receive one of two anesthesia regimens: continuous epidural infusion of ropivacaine and morphine, along with intravenous infusion of ketamine (0.05 mg . kg(-1) . h(-1) [approximately 3 mg/h], ketamine group, n = 24) or placebo (saline, control group, n = 25). Epidural analgesia was continued for 2 days after surgery, and infusion of ketamine or placebo was continued for 3 days. Pain was assessed at 6, 12, 24, and 48 h after surgery. Patients were asked about their pain, abnormal sensation on the wound, and inconvenience in daily life at 7 days and 1, 3, and 6 months after surgery. RESULTS: The visual analog scale scores for pain at rest and on coughing 24 and 48 h after thoracotomy were lower in the ketamine group than in the control group (pain at rest, 9 +/- 11 vs. 25 +/- 20 and 9 +/- 11 vs. 18 +/- 13; pain on coughing, 26 +/- 16 vs. 50 +/- 17 and 30 +/- 18 vs. 43 +/- 18, mean +/- SD; P = 0.002 and P = 0.01, P < 0.0001 and P = 0.02, respectively). The numerical rating scale scores for baseline pain 1 and 3 months after thoracotomy were significantly lower in the ketamine group (0.5 [0-4] vs. 2 [0-5] and 0 [0-5] vs. 1.5 [0-6], median [range], respectively; P = 0.02). Three months after surgery, a higher number of control patients were taking pain medication (2 vs. 9; P = 0.03). CONCLUSIONS: Very-low-dose ketamine (0.05 mg . kg(-1) . h(-1)) potentiated morphine-ropivacaine analgesia and reduced postthoracotomy pain.

Aged↗
PubMed2006

Clinical features of cauda equina tumors requiring surgical treatment.

In this study, we evaluated the clinical features of cauda equina tumors requiring surgical treatment. Medical records of 28 patients with cauda equina tumors (13 men and 15 women) undergoing surgical treatment were retrospectively reviewed. The majority of histological diagnoses indicated schwannoma (23 cases, 82%), and the remaining 5 indicated ependymoma, neurofibroma, meningioma, and ganglioneuroblastoma. In 86% of the cases, the initial symptom was pain in the lower back and/or lower extremities. Preoperatively, half of the patients had symmetrical pain in the lower back or lower extremities, severe pain in the supine position, or pain that was increased by coughing. One third of the patients needed morphine to control nocturnal pain. Tumor size, as determined by magnetic resonance imaging (MRI), correlated with preoperative symptom duration (r = 0.66, p < 0.001). These findings indicate that symmetrical lower back pain and/or pain that radiates to both lower extremities and increases in the supine position are characteristic of cauda equina tumors. The correlation between symptom duration and tumor size indicates that earlier diagnosis of this tumor is necessary. Earlier diagnosis based on these characteristic symptoms should make use of further examinations such as MRI.

Adolescent↗
PubMed2006

Hybrid functional electrical stimulation with medial linkage knee-ankle-foot orthoses in complete paraplegics.

We have previously restored ambulation in paraplegics by performing hybrid functional electrical stimulation (FES) with medial linkage knee-ankle-foot orthosis (MLKAFO). The most common MLKAFO (hinge-type MLKAFO) has the hypothetical axis that is lower than the physiological hip joint position, resulting in slow velocity and short step length. A new MLKAFO (sliding-type MLKAFO), which uses sliding medial linkages, has been developed to correct the axial discrepancy of the hinge-type MLKAFO that causes limited hip joint excursion. There have been reports of instability associated with sliding medial linkages, but the mechanism of this instability is unclear. The purpose of the present study was to evaluate the effects of FES with MLKAFOs on ambulation in paraplegics. Two complete paraplegic patients (levels T8 and T12, respectively) participated in this study. Kinematics data during ambulation were obtained using a motion analysis system. We measured gait velocity and hip progression during the standing phase. The sliding-type MLKAFO produced faster gait velocity than did the hinge-type MLKAFO, but it caused pelvis instability without FES. Pelvis instability was controlled by hybrid FES using the sliding-type MLKAFO. With hybrid FES, the sliding-type MLKAFO provides better gait performance than the hinge-type MLKAFO, but the hinge-type MLKAFO provides greater pelvis stability during walking. Moreover, FES provides sufficient propulsion to allow the complete paraplegics to walk.

Adult↗
PubMed2006

Chronic subdural hematoma coexisting with ligamentum flavum hematoma in the lumbar spine: a case report.

We present a case of a chronic spinal subdural hematoma combined with a ligamentum flavum hematoma in the lumbar spine treated surgically. An 83-year-old woman receiving antiplatelet medicine due to an angina suffered from pain in her lower extremity and gait disturbance after a backward fall. Radiological findings including magnetic resonance imaging (MRI) revealed hematoma in the ligamentum flavum at the level of L2 - L3 and a chronic subdural hematoma at the level from L3 to L5. Laminectomy through L2 to L5 was performed and a hematoma existing in the ligamentum flavum and cystic mass was removed. A chronic subdural hematoma was spontaneously evacuated after splitting of the dura mater and an intact arachnoid membrane was observed with no leakage of cerebrospinal fluid. Her clinical symptoms completely disappeared after surgery. To the best of our knowledge, this is the first case of combination of chronic subdural hematoma and ligamentum flavum hematoma in the lumbar spine treated by surgery. Chronic spinal subdural hematoma and hematoma in the ligamentum flavum should be considered as a cause of progressive nerve root compression in patients with anticoagulant therapy, and an appropriate pre-operative diagnosis would be needed to achieve complete decompression of subdural and epidural hematoma.

Aged, 80 and over↗
PubMed2006

Ligamentum flavum hematoma in the cervical spine - case report.

A 67-year-old man presented with a rare case of ligamentum flavum hematoma manifesting as progressive tetraplegia following cervical traction therapy. Magnetic resonance imaging of the cervical spine showed a posterior mass that was continuous with the ligamentum flavum at the C3-4 levels. Complete resection of the mass that contained brownish hemorrhage was performed, resulting in excellent symptom relief. We speculate that repeated trivial trauma to the degenerative ligamentum flavum was the main predisposing factor in the present case. Ligamentum flavum hematoma is a rare cause of spinal root or cord compression which typically occurs in the lower thoracic or lumbar spine, but may also appear in the cervical spine.

Aged↗
PubMed2006

Reduction of muscle fatigue by catchlike-inducing intermittent electrical stimulation in rat skeletal muscle.

Catchlike property is the force enhancement produced when a brief, high-frequency burst of pulses is added to a constant low-frequency stimulation. In functional electrical stimulation, constant low-frequency stimulation of approximately 20 Hz has primarily been used to reduce muscle fatigue. The purpose of this study was to investigate the effects of catchlike-inducing intermittent stimulation on muscle fatigue in relation to continuous intermittent low-frequency stimulation. Twenty-two adult male Wistar ST rats were randomly assigned into the constant frequency stimulation (CFS) group or the catchlike-inducing stimulation (CIS) group. In the CFS group, constant low-frequency stimulation of 20 Hz was applied intermittently (4 seconds "ON"/15 seconds "OFF"). In the CIS group, a single electrical burst of 100 Hz was applied at the start of the every 4-second period of stimulation. The muscle fatigue test lasted for 16 min and isometric muscle force, muscle fatigue, and muscular workload were evaluated. CIS significantly increased the maximum muscular force (under fatigued condition) and workload, and significantly decreased muscle fatigue (p < 0.05). The results of this study suggest that catchlike-inducing intermittent electrical stimulation is useful in the clinical administration of functional electrical stimulation.

Animals↗
PubMed2006

Effects of therapeutic magnetic stimulation on acute muscle atrophy in rats after hindlimb suspension.

In most subjects with spinal cord injury, the spinal neurons below the level of injury are spared. Therefore, it is conceivable that the skeletal muscles innervated by these spinal nerves can be activated by applying therapeutic magnetic stimulation along the dorsal spine. The purpose of this study was to evaluate the ability of magnetic stimulation to prevent acute muscle atrophy in rats after hindlimb suspension. Forty adult male Wistar rats were randomly assigned to stimulated and non-stimulated (control) groups. Their hindlimbs were unweighted using a suspension method, causing muscle atrophy. In the stimulation group, magnetic stimulation (20 Hz, 60 min per day) was applied to the sciatic nerve for 10 days. After the stimulation period, the tibialis anterior (TA) and extensor digitorum longus (EDL) were surgically removed and histologically measured. The lesser diameters of type 1, 2A, and 2B muscle fibers were significantly greater in the stimulated group than in the non-stimulated group for both the TA and EDL (p < 0.05). The mean difference in lesser fiber diameter was 20% (range, 14%-27%). These results suggest that therapeutic magnetic stimulation is an effective method of preventing muscle atrophy.

Acute Disease↗
PubMed2006

Decompression of idiopathic lumbar epidural lipomatosis: diagnostic magnetic resonance imaging evaluation and review of the literature.

OBJECT: Idiopathic symptomatic spinal epidural lipomatosis (SEL) is a rare condition, and few reports have discussed diagnostic imaging criteria. To evaluate factors relating to its clinical symptoms, correlations between clinical features and the presence of spinal epidural fat were investigated, and the literature concerning idiopathic SEL was reviewed. METHODS: Morphological gradings of epidural fat were evaluated in seven patients with idiopathic SEL by using magnetic resonance (MR) imaging. In addition, body mass index (BMI), the number of involved vertebral levels, grade, and preoperative Japanese Orthopaedic Association (JOA) score were analyzed. Surgery resulted in symptomatic relief, with a mean JOA score recovery rate of 67.4%. Grading of epidural fat tended to display a slight negative correlation with preoperative JOA score, whereas a strong significant positive correlation was found between the number of involved vertebral levels and BMI. CONCLUSIONS: The number of involved vertebral levels and obesity are strongly correlated, whereas severity of dural compression is not always significantly associated with neurological complications. These results indicate that epidural fat of the lumbar spine contributes to neurological deficits. In addition, weight-reduction therapy appears to decrease the number of vertebral levels involved. Magnetic resonance imaging-based grading is helpful for the diagnosis and evaluation of idiopathic lumbar SEL. Moreover, symptoms and neurological findings are important for determining the surgical approach.

Adipose Tissue↗
PubMed2006

Spondylolisthesis of the thoracic spine. Case report.

The thoracic spine is stabilized in the anteroposterior direction by the rib cage and the facet joints. Spondylolisthesis of the thoracic spine is less common than that of the lumbar spine. The authors describe a rare case of thoracic spondylolisthesis in which the patient suffered back pain and myelopathy. The patient was a 44-year-old woman. Plain radiography revealed Grade I T11-12 spondylolisthesis. The pedicle-facet joint angle at T-11 was 118 degrees, greater than that of T-10 or T-12. Postmyelography computerized tomography scanning revealed posterior compression of the dural sac as well as enlargement of and degenerative changes in the facet joint at T-11. Magnetic resonance imaging showed anterior and posterior compression of the spinal cord at the level of the spondylolisthesis. To achieve posterior T10-12 decompression, the surgeons performed a laminectomy and posterolateral fusion in which a pedicle screw fixation system was placed. The patient's back pain disappeared immediately after the operation. The authors conclude that the enlargement of the pedicle-facet joint angle and the degenerative changes of the facet joint caused the thoracolumbar spondylolisthesis.

Adult↗
PubMed2006

Objective evaluation of shoulder pain by measuring skin impedance.

The subjective nature of pain has made its objective evaluation rather difficult. Recently, skin impedance was reported to reflect pain. The purpose of this study was to determine the usefulness of measuring skin impedance in evaluating shoulder pain. Fifty-three patients with shoulder pain were examined. Skin impedance was measured by a skin impedance meter in three different conditions and was compared with the visual analog scale recorded at the same time.

Adult↗
PubMed2006

[Effects of methylergometrine and oxytocin on blood loss and uterine contraction during cesarean section].

BACKGROUND: The effects of intravenous oxytocics on blood loss and uterine contraction during cesarean section were studied in 136 parturients. METHODS: The subjects were randomized to receive either methylergometrine 0.2 mg bolus (MEM group; n = 34), oxytocin 10 IU over 30 seconds (OX 30 s group; n = 34), oxytocin 10 IU over 5 minutes (OX 5 m group; n = 34) or oxytocin 10 IU over 15 minutes (OX 15 m group; n = 34). The subjects received spinal anesthesia with 11-12 mg of intrathecal isobaric bupivacaine (0.5%). Additional intramyometrial prostaglandin F2alpha (PGF2alpha) was administered when obstetrician diagnosed uterine atony. We analyzed total amount of blood loss including amniotic fluid and number of parturients that received additional intramyometrial PGF2alpha to evaluate uterine contraction. RESULTS: The amounts of blood loss in the OX 30 s and OX 5 m groups were significantly lower than in the MEM group, and the numbers of parturients received additional PGF2alpha in all the oxytocin treat ment groups were significantly lower than in the MEM group (P < 0.05). There were no significant differences in blood loss and uterine contractior among the oxytocin treatment groups. CONCLUSIONS: Intravenous oxytocin 10 IU over 30 seconds to 15 minutes was effective to decrease blood loss and uterine contraction than intravenous methylergometrine 0.2 mg bolus.

Adult↗
PubMed2005

Effects of intraarticular administration of basic fibroblast growth factor with hyaluronic acid on osteochondral defects of the knee in rabbits.

INTRODUCTION: Growth factors including basic fibroblast growth factor (bFGF) are expected to be useful tools for enhancing osteochondral repair. However, suitable carriers are required to deliver a growth factor to the injury site. We evaluated the effects of intraarticular injection of bFGF with hyaluronic acid (HA) on osteochondral repair and the potential carrier role of HA in this treatment. MATERIALS AND METHODS: Osteochondral defect was created in the medial femoral condyle of rabbits and received single or weekly intraarticular injection of bFGF (1 or 10 microg) with or without HA. Prior to the administration, bFGF was incubated with HA or vehicle-saline for 24 h at 4 degrees C. Four weeks after the initial injection, the animals were killed and the defect was evaluated grossly (12-point scale) and histologically (16-point scale). The effect of single injection of bFGF (1 microg) with HA was also compared to that of the carrier known as gelatin microspheres (GM) incorporating bFGF. RESULTS: Weekly-administered bFGF alone induced undesirable side effects such as inflammatory responses and osteophyte formation. However, weekly-administered 1 mug of bFGF with HA yielded significantly better osteochondral repair than each treatment alone in gross and histological examinations with minimal side effects (P < 0.05). Single administration of 1 microg bFGF with HA but not GM incorporating bFGF showed significantly better osteochondral repair comparing to the vehicle control (P < 0.05). CONCLUSION: Low-dose bFGF with HA was effective for osteochondral repair in rabbits. The significant osteochondral reparative role of bFGF with HA comparing with GM incorporating bFGF might be explained by the potential carrier role of HA and possible synergistic action between these two agents. The combination of HA with bFGF significantly suppressed the side effects resulting from single use of bFGF.

Adjuvants, Immunologic↗