We present a case involving a 38-year-old female with persistent back pain and hyperalgesia following schwannoma resection. Collision testing demonstrated a significant decrease in SSEP amplitudes upon stimulating the L4 nerve root, indicating its role in pain transmission. This localized the L4 nerve root's contribution to sensory signaling from the dorsum of the foot and guided placement of the NRS. Postoperatively, the patient experienced substantial pain relief in the tested area, though pain in other locations necessitated a spinal cord stimulator placement afterwards.

In this case, we demonstrated a change in cortical SSEP during collision studies of the L4 nerve root while stimulating the dorsal aspect of the foot. This change correlated with postoperative pain relief in the foot after NRS placement at the L4 nerve root. These findings suggest that collision studies may accurately predict the contribution of the individual nerve roots in transmitting sensory signals from various dermatomes. This case highlights the therapeutic potential of targeted NRS placement and supports further investigation into personalized pain management through precise nerve root stimulation and collision studies.