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Publications (3)6.59 Total impact

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    ABSTRACT: Study Design. Single center retrospective study.Objective. To reveal the characteristic changes in central motor conduction time (CMCT) produced by transcranial magnetic stimulation among the responsible levels of cervical compressive myelopathy (CCM).Summary and Background. CMCT is a useful and noninvasive measure for evaluating the central motor pathway. However, a systematic correlation between CMCT findings and the responsible level of CCM has so far not been addressed in a large patient cohort.Method. We measured CMCT in 75 patients with CCM who were determined by intraoperative spinal cord evoked potentials (SCEPs) to have a single site of conduction abnormality at the intervertebral level. Twenty one healthy controls were also evaluated. Motor evoked potentials (MEPs), compound muscle action potentials and F-wave were recorded from bilateral abductor digiti minimi (ADM) and abductor hallucis muscles (AH). CMCT was calculated as follows: MEPs latency-(CMAPs latency + F latency-1)/2 (ms).Result. The mean values of ADM-CMCT and AH-CMCT at each responsible level were significantly longer compared to normal values (P<0.01). However the mean value of ADM-CMCT at the C6/7 level was markedly shorter than at the other levels, while the mean values of AH-CMCT were not significantly different between each responsible level. We determined that an ADM-CMCT longer than 7.9ms (mean + 2.5 SD) was abnormal. Using this definition, the sensitivity of ADM-CMCT for CCM was 92% for C3/4 myelopathy, 95% for C4/5, 58% for C5/6 and 9% for C6/7.Conclusion. ADM-CMCT is useful for the screening of CCM rostral to the C5/6 level. Diagnosis of patients with C6/7 myelopathy should include assessment of the AH-CMCT.
    Spine 11/2014; · 2.45 Impact Factor
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    ABSTRACT: Study design:A retrospective study.Objective:To elucidate the correlation between compound muscle action potentials (CMAPs) amplitudes and responsible level of compressive cervical myelopathy (CCM), and the accuracy of level diagnosis by using CMAPs.Setting:This study was conducted at the Department of Orthopedic surgery, Yamaguchi University Graduate School of Medicine, Japan.Method:A total of 28 patients with CCM were investigated in this study. Erb's point-stimulated CMAPs were measured from deltoid, biceps, triceps in all patients as compared with 88 healthy subjects. We performed a level diagnosis on the basis of CMAPs amplitudes. We performed a level diagnosis on the basis of CMAPs amplitudes and using an index that measures the deviation of CMAPs amplitudes between triceps and deltoid or biceps.Results:Significant correlations between the mean CMAPs amplitudes and responsible level were showed for deltoid (6.82±2.33 mV) at C3/4 (P<0.01) and biceps (8.75±4.42 mV) at C4/5 (P=0.015). Despite considerable individual variability in CMAP amplitudes, there were correlations among CMAPs amplitudes for deltoid, biceps and triceps in the same individual. The sensitivity was 75.0%, specificity 75.0% in the index for diagnosis of C3/4. The sensitivity was 75.0%, specificity 66.7% in the index for diagnosis of C4/5.Conclusion:This study showed small CMAPs amplitudes in the deltoid indicated a C3/4 level of myelopathy and in biceps at the C4/5 level and could help exclude clinically silent cord compression and determine the surgical procedure to the suitable level of concern.Spinal Cord advance online publication, 10 December 2013; doi:10.1038/sc.2013.149.
    Spinal Cord 12/2013; · 1.70 Impact Factor
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    ABSTRACT: STUDY DESIGN.: Case studies of patients with cervical spondylotic amyotrophy used compound muscle action potentials (CMAPs) of deltoid and biceps brachii muscles and central motor conduction time (CMCT). OBJECTIVE.: To discuss surgical outcome for proximal-type cervical spondylotic amyotrophy in the context of results obtained with CMAPs and CMCT. SUMMARY OF BACKGROUND DATA.: There have been no reports that correlate surgical outcome with CMAPs of deltoid and biceps brachii muscles or with CMCT. METHODS.: A retrospective study was performed for 24 patients with proximal-type cervical spondylotic amyotrophy who underwent surgical treatment of the cervical spine. Erb-point-stimulated CMAPs were recorded in the deltoid and biceps. The percent amplitude of CMAPs was calculated in comparison with the opposite side. Motor-evoked potentials were recorded from bilateral abductor digiti minimi. CMAPs and F waves were recorded after supramaximal electric stimulation of ulnar nerves. CMCT was calculated as follows: motor-evoked potentials latency - (CMAPs' latency + F latency - 1)/2 (ms). Muscle strength was evaluated using manual muscle testing. Improvements in strength were classified as excellent, good, or fair. RESULTS.: The improvement was graded as excellent in 12 cases, good in 2 cases, and fair in 10 cases. The average percentage for CMAPs' amplitude on the affected side compared with the normal side in deltoid and biceps brachii muscles was significantly different between the excellent and fair patient groups. The CMCT on the affected side was not significantly different between excellent and fair patient groups. CONCLUSION.: The average percentage range of deltoid and biceps brachii muscle CMAPs' amplitude determined at the onset of illness correlated significantly with postoperative recovery. Surgical intervention of the cervical spine should be performed in patients in whom the average percentage of CMAPs' amplitude in deltoid and biceps brachii muscles ranges from 30% to 50%.
    Spine 08/2012; 37(23):E1444-9. · 2.45 Impact Factor