False-negative transcranial motor evoked potentials (TcMEPs) during surgery for congenital lumbar kyphoscoliosis: a case report

摘要: Transcranial motor evoked potential (TcMEP) monitoring is the gold standard for intra-operative neurological (IOM) of pathways during complex spine surgery because its high sensitivity and specificity. However, although it very low, rate false-negatives in TcMEP not zero. Therefore, over-reliance on can cause potentially preventable deficits. We report a case deficits due to nerve root stretch after surgical correction congenital lumbar kyphoscoliosis 56-year-old woman. TcMEPs did show any significant changes surgery, whereas free-run electromyography (EMG) demonstrated long-lasting train activity left quadriceps femoris muscle (QF) at osteotomy area. According normal findings monitoring, we release correction. Postoperatively, decrease (grade 2-) manual test QF iliopsoas hypesthesia anterior thigh was revealed. Fortunately, strength fully recovered without revision 6 months postoperatively; however, numbness persisted 2 years surgery. Our suggests that possibility false-negative should be kept mind, especially with risk injury. When abnormal EMG, including activity, are observed, surgeons consider performing appropriate responses, such as correction, even when no substantial seen TcMEPs.