Neurosurg Focus
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Many patients develop neurological symptoms related to spinal cord tethering after perinatal repair of myelomeningocele. This is referred to as secondary tethered cord syndrome (STCS). The authors describe their methodology and evaluate the intraoperative utility and postoperative outcomes of electrophysiologically guided untethering for STCS. In addition, the authors describe the use of electrophysiological guidance to identify an "autonomous placode" in the untethering of the cord in STCS. ⋯ Surgical untethering of STCS halts progression and often improves preoperative symptoms. Electrophysiological monitoring, using both a threshold-based interpretation system and continuous electromyography monitoring, provides an efficient, effective, and reliable method for intraoperative guidance, thereby limiting iatrogenic injury and providing a means to identify and untether autonomous placodes. Electrophysiological monitoring also allows for more aggressive dissection and untethering in functionally silent regions, possibly decreasing retethering rates.
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Case Reports
Human motor evoked potential responses following spinal cord transection: an in vivo study.
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. ⋯ 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.