Transcranial magnetic stimulation in patients with cervical spondylotic myelopathy: Clinical and radiological correlations

Tavy, D.L.J.; Wagner, G; Keunen, R.W.M.; Wattendorff, A.R.; Hekster, R. E. M.; Franssen, Hessel

doi:10.1002/mus.880170215

Cited by 70 publications

(33 citation statements)

References 25 publications

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“…9,19 Central motor conduction time (CMCT) can be measured to evaluate corticospinal function in cervical myelopathy. 2,10,25,36 In fact, there is an excellent correlation between MRI findings and CMCT in patients with cervical myelopathy. 17 Central motor conduction time is more prolonged in patients with more severe cervical spinal cord compression, according to MRI analysis.…”

mentioning

confidence: 98%

Electrophysiological evidence of functional improvement in the corticospinal tract after laminoplasty in patients with cervical compressive myelopathy

Nakanishi¹,

Tanaka²,

Kamei³

et al. 2014

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Object Cervical laminoplasty is a surgical procedure for cervical compressive myelopathy (CCM), and satisfactory outcomes have been reported. However, few reports have examined the pathophysiology of improvements in spinal cord function. The aim of this study was to investigate the variation in central motor conduction time (CMCT) before and after cervical laminoplasty in patients with CCM. Methods Motor evoked potentials (MEPs) following transcranial magnetic stimulation and compound muscle action potentials (CMAPs) and F-waves following electrical stimulation of the ulnar and tibial nerves at the wrist and ankle were measured from the abductor digiti minimi muscle (ADM) and abductor hallucis muscle (AH) in 42 patients with CCM before and 1 year after cervical laminoplasty. The peripheral conduction time (PCT) was calculated as follows: (latency of CMAPs + latency of F-waves − 1)/2. The CMCT was calculated by subtracting the PCT from the onset latency of the MEPs. The CMCT recovery ratio was defined and calculated as the ratio of CMCT values 1 year after surgery to those before surgery. The CMCT data were analyzed as longer or shorter CMCT between the patients' right and left ADMs and AHs. The Japanese Orthopaedic Association (JOA) score for cervical myelopathy was obtained as a clinical outcome before and 1 year after surgery. The recovery rate (RR) 1 year after surgery was calculated using the following formula: (postoperative JOA score 1 year after surgery – preoperative JOA score)/(17 – preoperative JOA score) × 100. Correlations among CMCT parameters, patient age, JOA score, and RR were determined. Results The longer and shorter CMCTs from the ADM (longer, p = 0.000; shorter, p = 0.008) and the longer CMCT from the AH (longer, p = 0.000) before surgery decreased significantly 1 year after surgery; the shorter CMCT from the AH did not significantly differ (shorter, p = 0.078). The mean JOA score before surgery was 10.1 ± 3.0 and improved significantly to 12.9 ± 2.7 at 1 year after surgery (p = 0.000). The mean CMCT recovery ratio and RR were 0.91 ± 0.18 and 0.43 ± 0.27, respectively. The longer/shorter CMCT parameters in the ADM and AH before or 1 year after surgery correlated significantly with the JOA score both before and 1 year after surgery. The CMCT recovery ratio from the longer CMCT in the ADM correlated significantly with the RR (r = − 3090, p = 0.011). There were no significant correlations between age and any CMCT parameters or CMCT recovery ratios. Conclusions These results suggest that cervical laminoplasty improves corticospinal tract function 1 year after surgery, which may be one of the reasons for the JOA score improvements in patients with CCM. The degree of improvement in corticospinal tract function did not correlate with patient age in this case series. The results demonstrated quantitative evidence of the pathophysiology of functional recovery in the corticospinal tract following cervical laminoplasty in patients with CCM.

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mentioning

confidence: 98%

Electrophysiological evidence of functional improvement in the corticospinal tract after laminoplasty in patients with cervical compressive myelopathy

Nakanishi¹,

Tanaka²,

Kamei³

et al. 2014

SPI

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“…Since the introduction of TMS of the human motor cortex, the use of MEPs in the evaluation of many kinds of myelopathy has been well described [11][12][13][14]. The conduction time from the motor cortex to the anterior horn cell (CMCT) is a measure of the integrity of corticospinal pathways [15]. In particular, there is a correlation between the CMCT prolongation and the clinical disability [12,16].…”

Section: Discussionmentioning

confidence: 99%

Quantitative assessment of myelopathy patients using motor evoked potentials produced by transcranial magnetic stimulation

et al. 2009

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Motor evoked potentials (MEPs) study using transcranial magnetic stimulation (TMS) may give a functional assessment of corticospinal conduction. But there are no large studies on MEPs using TMS in myelopathy patients. The purpose of this study is to confirm the usefulness of MEPs for the assessment of the myelopathy and to investigate the use of MEPs using TMS as a screening tool for myelopathy. We measured the MEPs of 831 patients with symptoms and signs suggestive of myelopathy using TMS. The MEPs from the abductor digiti minimi (ADM) and abductor hallucis (AH) muscles were evoked by transcranial magnetic brain stimulation. Central motor conduction time (CMCT) is calculated by subtracting the peripheral conduction time from the MEP latency. Later, 349 patients had surgery for myelopathy (operative group) and 482 patients were treated conservatively (nonoperative group). CMCTs in the operative group and nonoperative group were assessed. MEPs were prolonged in 711 patients (86%) and CMCTs were prolonged in 493 patients (59%) compared with the control patients. CMCTs from the ADM and AH in the operative group were significantly more prolonged than that in the nonoperative group. All patients in the operative group showed prolongation of MEPs or CMCTs or multiphase of the MEP wave. MEP abnormalities are useful for an electrophysiological evaluation of myelopathy patients. Moreover, MEPs may be effective parameters in spinal pathology for deciding the operative treatment.

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“…A number of studies have demonstrated that almost all patients with cervical spondylotic myelopathy (CSM) present an MEP abnormality for distal upper limb muscles and for lower limb muscles. [9][10][11][12][13][14][15][16][17][18][19] For careful assessment of the cervical spinal cord, MEPs should be recorded from multiple upper limb muscles corresponding to different segmental levels. 18 In patients with a high cervical cord compression, the CMCT is prolonged for biceps brachii and distal hand muscles.…”

Section: Compressive Myelopathymentioning

confidence: 99%

Central motor conduction studies in patients with spinal cord disorders: a review

et al. 2014

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Transcranial magnetic stimulation in patients with cervical spondylotic myelopathy: Clinical and radiological correlations

Cited by 70 publications

References 25 publications

Electrophysiological evidence of functional improvement in the corticospinal tract after laminoplasty in patients with cervical compressive myelopathy

Electrophysiological evidence of functional improvement in the corticospinal tract after laminoplasty in patients with cervical compressive myelopathy

Quantitative assessment of myelopathy patients using motor evoked potentials produced by transcranial magnetic stimulation

Central motor conduction studies in patients with spinal cord disorders: a review

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