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 OF BACKGROUND DATA: 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 to have a single site of conduction abnormality at the intervertebral level. Twenty-one healthy controls were also evaluated. Motor evoked potentials, compound muscle action potentials, and F wave were recorded from bilateral abductor digiti minimi (ADM) and abductor hallucis (AH) muscles. CMCT was calculated as follows: motor evoked potentials 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 than those of normal values (P<0.01). However, the mean value of ADM-CMCT at the C6-C7 level was markedly shorter than those at the other levels, whereas the mean values of AH-CMCT were not significantly different between each responsible level. We determined that an ADM-CMCT longer than 7.9 ms (mean+2.5 standard deviation) was abnormal. Using this definition, the sensitivity of ADM-CMCT for CCM was 92% for C3-C4 myelopathy, 95% for C4-C5, 58% for C5-C6, and 9% for C6-C7. CONCLUSION: ADM-CMCT is useful for the screening of CCM rostral to the C5-C6 level. Diagnosis of patients with C6-C7 myelopathy should include assessment of the AH-CMCT. LEVEL OF EVIDENCE: 4.
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 OF BACKGROUND DATA: 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 to have a single site of conduction abnormality at the intervertebral level. Twenty-one healthy controls were also evaluated. Motor evoked potentials, compound muscle action potentials, and F wave were recorded from bilateral abductor digiti minimi (ADM) and abductor hallucis (AH) muscles. CMCT was calculated as follows: motor evoked potentials 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 than those of normal values (P<0.01). However, the mean value of ADM-CMCT at the C6-C7 level was markedly shorter than those at the other levels, whereas the mean values of AH-CMCT were not significantly different between each responsible level. We determined that an ADM-CMCT longer than 7.9 ms (mean+2.5 standard deviation) was abnormal. Using this definition, the sensitivity of ADM-CMCT for CCM was 92% for C3-C4 myelopathy, 95% for C4-C5, 58% for C5-C6, and 9% for C6-C7. CONCLUSION: ADM-CMCT is useful for the screening of CCM rostral to the C5-C6 level. Diagnosis of patients with C6-C7 myelopathy should include assessment of the AH-CMCT. LEVEL OF EVIDENCE: 4.
Authors: M Funaba; T Kanchiku; Y Imajo; H Suzuki; Y Yoshida; N Nishida; K Fujimoto; T Taguchi Journal: Spinal Cord Date: 2015-11-17 Impact factor: 2.772
Authors: Joke Rijckaert; Bart Pardon; Luc Van Ham; Philip Joosten; Gunther van Loon; Piet Deprez Journal: BMC Vet Res Date: 2018-09-24 Impact factor: 2.741