“Threshold-level” multipulse transcranial electrical stimulation of motor cortex for intraoperative monitoring of spinal motor tracts: description of method and comparison to somatosensory evoked potential monitoring

Calancie, Blair; Harris, William S.; Broton, James G.; Alexeeva, Natalia; Green, Barth A.

doi:10.3171/jns.1998.88.3.0457

Cited by 268 publications

(136 citation statements)

References 45 publications

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“…Of lower-limb muscles, AbH is typically the first-recruited using threshold-level repetitive transcranial electrical stimulation of motor cortex in the anesthetized patient during spine surgery. 11,37 Thresholds for recruiting this muscle with single-pulse transcranial magnetic stimulation in awake, neurologically intact subjects are typically equal to or lower than those for other lower-limb muscles. 10 In persons with incomplete cervical spinal cord injurymost of whom had been injured at least 1 year prior to testing -we showed that AbH was significantly more likely to be recruited by TMS than other lower-limb muscles, including hamstring, tibialis anterior, and soleus.…”

Section: Discussionmentioning

confidence: 99%

Abductor hallucis for monitoring lower-limb recovery after spinal cord injury in man

2004

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Study design: Electromyogram (EMG) study on patients with acute spinal cord injury (SCI). Objectives: We hypothesized that subjects with mild to moderate acute SCI would have a higher probability of recovering function in intrinsic muscles of the foot compared to more proximal lower-limb muscles, based on the relative density of corticospinal tract innervation to these different motoneuron pools. Setting: Miami and Syracuse, USA. Methods: We conducted repeated measures of EMG during voluntary contractions from lower-limb muscles in subjects with acute traumatic SCI. For this study, analysis was restricted to those subjects who had either no recruitment (ie 'motor-complete') or limited recruitment (ie 'motor-incomplete') in any lower-limb muscle of either leg during the initial evaluation, and all of whom had converted to a motor-incomplete status in one or both legs at the time of final evaluation. Recruitment of the abductor hallucis (AbH) muscle during contraction attempts was judged as being either 'present' or 'absent', based upon the presence or absence of EMG-based volitional motor unit recruitment. Results: A total of 70 subjects were included in this study. Of these, 58 had motor-incomplete injury at or rostral to the T10 vertebral level, and another 12 had injury caudal to T10. In the former group, the AbH muscle showed a recovery probability that was considerably higher than that of other lower-limb muscles. Quite the opposite pattern was seen in persons with injury caudal to T10. In these subjects, recruitment was more common in proximal muscles of the thigh (psoas and quadriceps), and least common in the AbH muscle. Discussion: For persons with SCI at or rostral to the T10 vertebral level, the AbH muscle proved to be an earlier and more sensitive indicator of lower-limb contraction recovery following acute SCI compared to other lower-limb muscles. Including this intrinsic muscle of the foot as part of a neurologic assessment of muscle function after SCI should increase the test's sensitivity to preserved (or restored) supraspinal motor influence over lower-limb motoneuron pools, and is recommended.

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Section: Discussionmentioning

confidence: 99%

Abductor hallucis for monitoring lower-limb recovery after spinal cord injury in man

2004

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“…The higher sensitivity (relative to SEPs) of MEPs to spinal cord dysfunction is consistent with previous reports. [11][12][13][14] There were no false negative SEPs or MEPs but 6 (75%) false-positive SEPs and 13 (65%) false-positive MEPs.…”

Section: Discussionmentioning

confidence: 99%

Combined motor- and somatosensory-evoked potential monitoring for spine and spinal cord surgery: correlation of clinical and neurophysiological data in 85 consecutive procedures

et al. 2009

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Study design: Prospective study. Objectives: The primary objective of neurophysiological monitoring during surgery is to prevent permanent neurological sequelae. To avoid neurological injury, we applied somatosensory-evoked potentials (SEPs) and/or motor-evoked potentials (MEPs). We evaluated whether the combination of SEP and MEP for spinal surgery may be beneficial. Setting: Asian Medical Center, University of Ulsan College of Medicine, Seoul, Korea. Methods: Combined SEP/MEP monitoring was attempted in 100 consecutive procedures for spinal operations. Trains of transcranial electrical stimulation over the motor cortex were used to elicit MEPs from the muscles of the upper/lower limbs. The tibial and median nerves were stimulated to record SEP. Results: Combined SEP/MEP recording was successfully achieved in 85 of 100 operations. In 61 of 85 operations (71%), SEP and MEP were stable, and all patients remained neurologically intact after surgery. Significant MEP changes were recorded in 20 operations, either combined with (n ¼ 4) or without (n ¼ 16) SEP changes. In 7 of these 20 operations, MEP recovered to some extent after surgical intervention, and these patients showed no neurological changes. In the remaining 13 operations, MEP did not recover and the patients had a transient (n ¼ 4) or a permanent (n ¼ 3) motor deficit. Significant SEP changes with stable MEP were observed in four operations, all of which were not related to postoperative motor deficit. Conclusion: Combined SEP/MEP monitoring provided higher sensitivity and higher positive/negative predictive value than single-modality monitoring techniques. Detection of MEP changes and adjustment of surgical strategy may prevent irreversible pyramidal tract damage.

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“…36 Furthermore, MEPs may be more sensitive to ischemia than SSEPs and less likely to deteriorate after midline myelotomy, unlike SSEPs. 4,5,7,10,12,24,[34][35][36]40 Also, as demonstrated in this case, not only will MEPs often be present in neurologically compromised patients, 9 but they may also be able to detect subclinical deficits, 3,23,38 whereas SSEPs are significantly more likely to be absent in the normal and compromised neurological states. In a recent prospective trial, 38.7% of patients undergoing a variety of spinal procedures had either significantly diminished or absent tibial SSEPs.…”

Section: Discussionmentioning

confidence: 89%

Human motor evoked potential responses following spinal cord transection: an in vivo study

Nair

Ramakrishna

Song³

et al. 2010

FOC

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Motor evoked potential (MEP) monitoring has been used increasingly in conjunction with somatosensory evoked potential monitoring to monitor neurological changes during complex spinal operations. No published report has demonstrated the effects of segmental spinal cord transection on MEP monitoring. The authors describe the case of an 11-year-old girl with lumbar myelomeningocele and worsening thoracolumbar scoliosis who underwent a T11–L5 fusion and spinal transection to prevent tethering. Intraoperative MEP and somatosensory evoked potential monitoring were performed, and the spinal cord was transected in 4 quadrants. The MEPs were lost unilaterally as each anterior quadrant was sectioned. This is the first reported case that demonstrates the link between spinal cord transection and MEP signaling characteristics. Furthermore, it demonstrates the relatively minor input of the ipsilateral ventral corticospinal tract in MEP physiology at the thoracolumbar junction. Finally, this study further supports the use of MEPs as a specific intraoperative neuromonitoring tool.

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“Threshold-level” multipulse transcranial electrical stimulation of motor cortex for intraoperative monitoring of spinal motor tracts: description of method and comparison to somatosensory evoked potential monitoring

Cited by 268 publications

References 45 publications

Abductor hallucis for monitoring lower-limb recovery after spinal cord injury in man

Abductor hallucis for monitoring lower-limb recovery after spinal cord injury in man

Combined motor- and somatosensory-evoked potential monitoring for spine and spinal cord surgery: correlation of clinical and neurophysiological data in 85 consecutive procedures

Human motor evoked potential responses following spinal cord transection: an in vivo study

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