脊椎脊髄手術における術中Free Running-EMG波形の分類と実用性

抄録

  Introduction : Transcranial motor evoked potentials (TcMEPs) and free-running electromyography (FR-EMG) are used for all microscopic spinal surgeries in our institute. During monitoring, characteristic spontaneous EMG (S-EMG) waves are observed, as well as false positive waves ; these are not easily differentiated. However, there is still no evidence of an association between S-EMG waves and neurological damage. In this paper, we describe the classification of S-EMG waves and the differentiation between dangerous and false positive waves.

  Method : S-EMG waves were classified into 7 types by their frequency and duration : single pulse, transient, intermittent, continuous, cyclic, sporadic, and mixed. The FR-EMG was monitored in 160 spinal surgical cases performed between September 1, 2015 and June 30, 2016. There were 47 cases of cervical spondylosis (CS), 7 of cervical ossification of the posterior longitudinal ligament (OPLL), 60 of lumbar canal stenosis (LCS), 22 of lumbar disc herniation (LDH), 13 of lumbar spondylolisthesis (LS), 13 of spinal tumor (ST), and 8 of spinal injury.

  Result : False positive waves were detected when the observer was aware of every aspect of the operation using both the FR-EMG and monitoring of the operative field. Abnormal waves were detected in 80% of LCS cases and 68% of CS cases. Short-duration waves were predominant in LCS surgery, and long duration waves were predominant in CS cases.

  Conclusion : Understanding of the wave types is essential for smooth communication between the operator and observer. FR-EMG should be used to avoid complications in spinal surgery.