Clinical utility of intraoperative direct wave monitoring in patients with pre-operative motor deficits: Case series.

Introduction And Importance: D-wave (Direct waves) are Motor Evoked Potentials (MEPs) generated by a single transcranial stimulation and captured by attaching an epidural recording electrode caudal to the vulnerable area. Intraoperative neurophysiologic monitoring (IONM) is widely used in neurosurgery to recognize important neurological structures but can be challenging in the pediatric population due to incomplete neural development.

Case Presentation: Case 1: A 48-year-old female presented to the outpatient department with complaints of difficulty walking for the past six months, numbness and weakness in bilateral lower limbs with recurrent falls for the past 1 month. Case 2: A 12-year-old boy presented to the emergency room with a history of inability to use both upper and lower limbs on the right side with tremulousness.

Clinical Discussion: Magnetic resonance imaging (MRI) Spine in the first case revealed a D9-D10 calcified meningioma with significant spinal cord compression. In the second case, MRI Spine showed C1-C2 Intramedullary Space Occupying Lesion (SOL) and was planned for C1-C2 laminectomy with midline myelotomy. The first case was planned for microsurgical excision of the lesion under IONM guidance. The procedure went smoothly. Microsurgical gross total resection (GTR) of the intramedullary SOL under IONM Guidance was done for the second case. Postoperatively, the first patient showed no neurological compromise or complications. In the second case, following surgery, the child recovered gradually from surgery.

Conclusion: This case series demonstrates the successful surgical management of two cases of spinal cord tumors through an IONM-guided surgery and the effective use of D waves in such challenging cases.