The diagnostic value of motor evoked potentials of musculus rectus abdominis in thoracic spinal cord injury / 中华骨科杂志

ABSTRACT

Objective To investigate the clinical application of transcranial magnetic stimulation motor evoked potentials (TMS-MEP) of rectus abdominis in the diagnosis of thoracic spinal cord injury. Methods The innervation of rectus abdominis and dermatomal distribution were studied in 5 adult cadavers. MEP of bilateral rectus abdominis in different segments was measured and recorded in 25 normal subjects for reference and in 23 patients with T4-T12 spinal cord injury. Results The anatomic study showed that rectus abdominis was innervated by 7 pairs of intercostal nerve from T6 to T12, useful to determine the MEP recording points in the body surface. In all normal subjects, T6-T12 MEP of bilateral rectus abdominis were recorded successfully and the referential range of normal MEP was established. The MEP peak latencies of each level were significantly different each with other. Among 23 patients suffering from thoracic spinal cord injury, 12 cases with complete paralysis had no MEP record below the injured level and no neurological recovery during the follow-up; while in 11 cases with incomplete paralysis, abnormal MEP were recorded in all but one with T4 fracture, the MEP of this patient disappeared below T6. The change of MEP of rectus abdominis was consistent with the level of fracture except in 1 case. During follow-up, 9 cases with incomplete paralysis patients showed recovery to different extent. Conclusion According to neuroanatomy, segmental MEP of rectus abdominis can be evoked and recorded in all normal subjects. The MEP peak latencies are significantly different in each level. MEP of rectus abdominis is proved to have the localizing and characteristic diagnostic value in the evaluation of the thoracic spinal cord injury.