Reversible Causes of Transitory Motor Evoked Potential Decrease During Posterior Spine Fusion in Rapidly Progressive Scoliosis Treatment: A Case Report

It is well known that motor responses can show variability during surgery, including a gradual decrease due to prolonged anesthesia. After excluding anesthetic and mechanical factors, one of the hypothetical explanations for the transient MEP loss was temporary venous congestion and retrograde flow within the intravertebral and epidural/intraspinal venous networks, resulting in reversible spinal cord drainage impairment. Another hypothetical possibility was transient vasospasm from surgical manipulation without direct neural or vascular injury. This case highlights the critical role of continuous multimodal neuromonitoring in detecting reversible spinal cord dysfunction and guiding safe decision-making during complex scoliosis surgery.