Akiko Misawa

Akita University Hospital, Akita, Akita, Japan

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Publications (34)20.68 Total impact

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    ABSTRACT: Comparison of nerve growth factor (NGF) and estrogen receptor (ER)α messenger ribonucleic acid (mRNA) expression in bilateral paravertebral muscles in adolescent idiopathic scoliosis (AIS). This expression in AIS was compared with that of normal control subjects.
    03/2015; 3(2). DOI:10.1016/j.jspd.2014.07.006
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    ABSTRACT: Abstract There has been only one reported case of neuromuscular scoliosis following chronic inflammatory demyelinating polyneuropathy (CIDP). However, no cases of scoliosis that were treated with surgery secondary to CIDP have been previously described. A 16-year-old boy with CIDP was consultant due to the progression of scoliosis with the coronal curve of 86° from T8 to T12. Posterior correction and fusion with segmental pedicle screws were performed under intraoperative spinal cord monitoring with transcranial electric motor-evoked potentials. Although the latency period was prolonged and amplitude was low, the potential remained stable. Coronal curve was corrected from 86° to 34° without neurological complications. We here describe scoliosis associated with CIDP, which was successfully treated with surgery under intraoperative spinal cord monitoring.
    Upsala journal of medical sciences 01/2013; 118(2). DOI:10.3109/03009734.2012.757682 · 1.71 Impact Factor
  • 01/2011; 77(775):980-988. DOI:10.1299/kikaic.77.980
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    ABSTRACT: Chronic expanding hematoma after spinal surgery is extremely rare, with no case previously reported in the literature. To report a rare case of a chronic expanding hematoma of the spine that occurred 24 years after thoracic laminectomy and spinal cord tumor resection. Case report. A 71-year-old man presented with a spinal mass located approximately at the level of the sixth thoracic vertebral body. The patient had undergone thoracic laminectomy with tumor resection 24 years previously. The mass had appeared 5 years after this and had gradually enlarged over 19 years. The tumor was resected en bloc. The lamina and spinous processes had been partially eroded by the tumor at the fifth and sixth thoracic vertebrae, but the dura was intact. Histopathologic examination confirmed the diagnosis of chronic expanding hematoma. The hematoma had not recurred at the 1-year follow-up. We report herein an extremely rare case of chronic expanding hematoma after spinal surgery. This entity may be considered a late complication after surgery regardless of the number of years that have passed since the index surgery.
    The spine journal: official journal of the North American Spine Society 11/2010; 10(11):e6-9. DOI:10.1016/j.spinee.2010.08.023 · 2.80 Impact Factor
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    ABSTRACT: Ganglioneuromas are rarely located in the cervical region compressing the spinal cord. Only two cases of bilateral and symmetric dumbbell tumor have been reported previously. The purpose of the study was to present an additional case with bilateral and symmetric dumbbell ganglioneuromas of the cervical spine as part of multiple ganglioneuromas of the spine in a patient with neurofibromatosis type 1 (NF-1). The study design was a case report. A 15-year-old boy with NF-1 presented with a 6-month history of progressive tetraparesis. Magnetic resonance imaging showed voluminous bilateral and symmetric dumbbell masses at the C1-C2 level severely compressing the spinal cord. The spinal cord was also indented by a dumbbell mass at the left C3-C4 level. A systemic imaging survey of the patient showed numerous asymptomatic foraminal and extraforaminal tumors at all neuroforamina of the spine. The result was found to be surgical decompression of the spinal cord by subtotal resections of bilateral tumors at the C1-C2 level and unilateral tumor at the left C3-C4 level alleviated patient symptoms. Histopathological diagnosis was ganglioneuroma for all resected tumors. Multiple ganglioneuromas, particularly bilateral and symmetric dumbbell tumors, are extremely rare but could be associated with NF-1.
    The spine journal: official journal of the North American Spine Society 04/2010; 10(4):e11-5. DOI:10.1016/j.spinee.2010.01.023 · 2.80 Impact Factor
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    Scoliosis 01/2009; DOI:10.1186/1748-7161-4-S1-O40 · 1.31 Impact Factor
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    ABSTRACT: Objective.  To assess the orthotic effect of a functional electrical stimulation device (Akita Heel Sensor System; AHSS) in the treatment of hemiplegic gait with foot drop. Materials and Methods.  In the AHSS, a heel sensor is attached to a small plastic heel brace, and the peroneal nerve is stimulated via percutaneous intramuscular electrodes. During the swing phase of the hemiplegic gait, the common peroneal nerve is stimulated by the AHSS. Eight patients in chronic stages of hemiplegia participated in this study. Walking speeds and step cadences on a 10-m course were compared between walking with stimulation and walking without stimulation. Results.  Mean walking speed (± SD) was 0.50 ± 0.26 m/sec without stimulation and 0.64 ± 0.31 m/sec with stimulation. The mean percentage increase in walking speed with stimulation was 30.1%. Mean step cadence was 31 ± 7 steps/10 m without stimulation and 27 ± 7 steps/10 m with stimulation. By correcting foot drop, the AHSS significantly increased walking speed and decreased cadence (p < 0.05). Conclusion.  The AHSS can significantly improve walking in hemiplegic patients with foot drop.
    Neuromodulation 10/2006; 9(4):320-7. DOI:10.1111/j.1525-1403.2006.00074.x · 1.79 Impact Factor
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    ABSTRACT: 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.
    Biomedical Research 09/2006; 27(4):183-9. DOI:10.2220/biomedres.27.183 · 1.10 Impact Factor
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    ABSTRACT: Objective. To evaluate the ability to relieve shoulder pain by implanting ceramic-case versions of radiofrequency microstimulators (RFM) in paralyzed shoulder muscles. Materials and Methods. A 66-year-old man, who had left-sided chronic hemiplegia due to a stroke five years previously, had developed shoulder subluxation resulting in pain. Two RFM devices were implanted, one next to the axillary nerve and one at the motor point of the middle deltoid muscle. Electrical stimulation at both sites was commenced two weeks after implantation for a six-month period. Our evaluation of the effectiveness of the RFM devices has been by measuring pain (using the visual analog scale: VAS), range of motion at the shoulder, strength of the deltoid muscle, degree of shoulder subluxation, and muscle atrophy. Following commencement of stimulation, follow-up evaluations were performed at one, two, three, four, and six weeks, three and six months, and after six months of no stimulation. Results. During the treatment period of six months of stimulation, the patient's pain had reduced from 70 to 0 on the VAS. At six months after completion of the treatment, pain relief and effective evoked muscle contraction have remained. Conclusion. Although these results suggest that the feasibility of using RFM devices implanted both epineurally to the axillary nerve and next to the muscle motor point in this one patient, to relieve pain and elicit contraction, further investigation is needed to demonstrate the clinical feasibility of using RFMs for treating poststroke shoulder pain.
    Neuromodulation 07/2006; 9(3):234-8. DOI:10.1111/j.1525-1403.2006.00065.x · 1.79 Impact Factor
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    ABSTRACT: 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.
    Biomedical Research 02/2006; 27(1):23-7. DOI:10.2220/biomedres.27.23 · 1.10 Impact Factor
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    ABSTRACT: Functional electrical stimulation (FES) can improve the gait of stroke patients by stimulating the peroneal nerve in the swing phase of the affected leg, causing dorsiflexion of the foot that allows the toes to clear the ground. A sensor can trigger the electrical stimulation automatically during the stroke gait. We previously used a heel sensor system, which detects the contact pressure of the heel, in FES to correct foot drop gait. However, the heel sensor has disadvantages in cosmetics and durability. Therefore, we have replaced the heel sensor with an acceleration sensor that can detect the swing phase based on the acceleration speed of the affected leg, using a machine learning technique (Neural Network). We have used a signal for heel contact in a gait using the heel sensor before training with the Neural Network. The accuracy of the Neural Network detector was compared with a swing phase detector based on the heel sensor. The Neural Network detector was able to detect similarly the swing phase in the heel sensor. The largest difference in timing of the swing phase was less than 60 milliseconds in normal subjects and 80 milliseconds in stroke patients. We were able to correct foot drop gait using FES with an acceleration sensor and Neural Network detector. The present results indicate that an acceleration sensor positioned on the thigh, which is cosmetically preferable to systems in which the sensor is farther from the entry point of the electrodes, is useful for correction of stroke gait using FES.
    The Tohoku Journal of Experimental Medicine 12/2005; 207(3):197-202. DOI:10.1620/tjem.207.197 · 1.28 Impact Factor
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    ABSTRACT: There are many papers reporting results from stimulating muscle groups for shoulder subluxation using surface and percutaneous electrodes. These electrodes have both advantages and disadvantages with respect to using them on a daily basis; thus, electrodes without external wires would be ideal. We have now experienced using the completely implantable RF-BION® microstimulators
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    ABSTRACT: Grasping power (GP) by means of functional electrical stimulation (FES) was measured in a case of C6 complete tetraplegia. This was compared with GP by means of the dynamic tenodesis effect, the flexor hinge splint and the GP of normal female. Palmar grasp strength by means of FES was approximately 16% of the control group and 2.4 times greater than the flexor hinge splint. Lateral grasp strength by FES was approximately 13% of the control group. Our results suggest that FES is more effective than the flexor hinge splint in increasing the GP of tetraplegic patients, and that a stronger and stable GP, which is not affected by wrist position, makes FES practical for improving activities of daily living (ADL).
    The Tohoku Journal of Experimental Medicine 11/2003; 201(2):91-6. DOI:10.1620/tjem.201.91 · 1.28 Impact Factor
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    ABSTRACT: To evaluate the effects of electric stimulation in preventing acute muscle atrophy after spinal cord transection in rats. A randomized experimental design. Animal facilities for experimental medicine. Fifty-six adult male Wistar rats assigned to control, low-frequency, and high-frequency groups. The rats were implanted with a percutaneous intramuscular electrode in the vicinity of the peroneal nerve; then the spinal cord was transected in a T9 level. The stimulation frequency was low (20Hz) or high (100Hz). The stimulation cycle was 4 seconds of stimulation every 8 seconds. The lesser fiber diameters from type 1, 2A, and 2B muscle fibers were measured. In another assessment, maximal contraction force was measured. The muscle force produced at 20 and 100Hz was expressed as increasing values in tetanic force. Comparison between nonstimulated and stimulated tibialis anterior muscles found that atrophy of type 1 fibers (p < .01) and type 2B fibers (p < .05) at both stimulated levels and of type 2A fibers at 100-Hz level (p < .05) was prevented by therapeutic electric stimulation (TES). There were significant differences in the size of muscle fiber diameter between nonstimulated and stimulated muscles at 100Hz in type 2A and, markedly, in type 2B. The increasing value of muscle force was significantly greater at 100Hz than at 20Hz (p < .05). No significant histologic differences were observed between high- and low-frequency stimulated fibers of any of the 3 muscle types. Acute atrophy of muscle fibers was more effectively prevented by high-frequency stimulation (100Hz) than by no stimulation or low-frequency stimulation (20Hz). The increasing value of muscle force was significantly greater at high-frequency than low-frequency stimulation, suggesting that the clinical application of high-frequency stimulation in acute spinal cord injury should be studied.
    Archives of Physical Medicine and Rehabilitation 11/2001; 82(11):1596-603. DOI:10.1053/apmr.2001.25990 · 2.44 Impact Factor
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    ABSTRACT: A closed-loop control system for standing with functional electrical stimulation (FES) using percutaneous intramuscular electrodes in complete paraplegia is described. The system consisted of ultrafine percutaneous intramuscular electrodes, a 32-channel stimulator and a stretch sensor with active current control to detect knee buckling. The closed-loop control system was applied in a T8 completely paraplegic patient. Compared to the stretch sensor with a wide use flexible goniometer for direct current control during standing, the stretch sensor was superior to the flexible goniometer in both ease of use and response. The average time delay from the start of knee buckling until the sensor turned on was 0.56+/-0.19 seconds (Mean+/-S.D.) in the goniometer and 0.21+/-0.06 seconds in the stretch sensor. The average time delay from the start of knee buckling until the recovery from knee buckling was 1.01+/-0.05 seconds in the goniometer and 0.78+/-0.06 seconds in the stretch sensor. The continuous standing ability of the patient increased from 12 minutes with open-loop stimulation to 30 minutes with the closed-loop control. No complications such as falling occurred during clinical use. This system prevented falling due to knee buckling during standing and prolonged upright activities in complete paraplegics.
    The Tohoku Journal of Experimental Medicine 03/2001; 193(3):221-7. DOI:10.1620/tjem.193.221 · 1.28 Impact Factor
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    ABSTRACT: Therapeutic electrical stimulation (TES) has been performed to increase muscle force, and to prevent muscle atrophy. In this study, we evaluated the differences in the effects on acute atrophied muscles after stimulation at different frequencies. The TA and EDL muscles of paraplegic Wistar male rats were used. An electrode was unilaterally inserted percutaneously in the vicinity of the peroneal nerve. The TA and EDL were stimulated for 60 min / day, at either 20 or 100 Hz, for up to 1 week. The TA and EDL muscles from both legs were surgically removed after stimulation. Muscle fibers were identified with ATPase stain, and the lesser fiber diameters were measured. A comparison between stimulated muscle and non-stimulated muscle was done. In type 2A and 2B, the lesser diameters, stimulated at 100 Hz, were significantly larger than those non-stimulated at 100 Hz on TA and EDL. In type 2B, the lesser diameter of TA stimulated at 100 Hz was significantly larger than that of TA stimulated at 20 Hz. These results support that high frequency stimulation for acute atrophied muscles are useful in reducing muscle atrophy.
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    ABSTRACT: OBJECTIVE> Swing through gait is mostly adopted to help locomotion for paraplegics. This gait pattern shows faster and lower energy consumption than a reciprocal gait for paraplegics. The purpose of this study was to investigate kinematics data during swing through gait motion due to produce a functional electrical stimulation pattern. Thirty-nine normal male subjects participated in this study. We measured the gait parameters during swing through gait with and without the short leg brace. The gait velocity, hip, knee, ankle joint angle, the joint moment, and the energy expenditure of the pectralis major muscle were calculated using the PEAK motion analysis system and the Kistler Force Plate. No statistical differences were observed between in the gait velocity and the cadence with and without the short leg brace. A hip flexion angle, knee extension moment, and energy expenditure of the pectoralis major muscle with the short leg brace was greater than without the brace. The results showed that the short leg brace can make a contribution to ankle joint stability, clearance in swing phase, and knee extension moment. It is necessary to stimulate a hip joint flexor muscle during swing through gait.
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    ABSTRACT: The aim of this study is to evaluate the ability to relieve pain by implanting and stimulating