Case Studies of Transcranial Electrical Motor Evoked Potentials (TCeMEP) on Patients with Charcot-Marie-Tooth Disease during Posterior Spinal Instrumentation and Fusion

Abstract

Neuromuscular disease can present many challenges to monitoring technologists in the operating room. This became evident when we received a request to monitor a patient with Charcot-Marie-Tooth disease during posterior spinal instrumentation and fusion for scoliosis. It has been well documented that the nerve conduction velocity is delayed with Charcot-Marie-Tooth disease (Pareyson et al. 2006). The latencies we normally encounter for somatosensory and motor evoked potentials for the upper extremity responses are between 15 and 20 msec, and for the lower extremity responses, are usually between 25 and 35 msec. Recording with a sweep of 100 msec, we assumed we could record a response with a significant delay. We never imagined we would need to increase the sweep time to 500 msec or more in order to record the responses from the lower extremities.

KEY WORDS:

• Charcot-Marie-Tooth disease
• latency
• scoliosis
• somatosensory evoked potential (SSEP)
• transcranial electrical motor evoked potential (TCeMEP)