Neuropathic lower extremity pain following dunn-mccarthy instrumentation

STUDY DESIGN: Retrospective review of all patients with intact spinal cords, who had posterior spinal fusion (PSF) to the pelvis with Dunn-McCarthy instrumentation. Inclusion criteria were communicative patients with Dunn-McCarthy instrumentation, functioning spinal cords, and sensate lower extremities. We excluded patients with myelomeningocele or spinal cord injury because they are physiologically unable to develop neuropathic lower extremity pain. We distinguished neuropathic lower extremity pain from positional discomfort by eliminating patients whose symptoms resolved in the first postoperative month and patients whose pain persisted greater than a month but did not require treatment or further investigation. OBJECTIVE: To determine the incidence and clinical course of neuropathic lower extremity pain following PSF with Dunn-McCarthy instrumentation. SUMMARY OF BACKGROUND DATA: The Dunn-McCarthy technique for instrumented PSF to the pelvis places a rod in close proximity to the L5 nerve root and anterior neurovascular structures. We have treated several patients who developed neuropathic lower extremity pain following PSF with Dunn-McCarthy instrumentation. RESULTS: Seven of 49 patients developed neuropathic pain in a lower extremity after PSF to the pelvis with Dunn-McCarthy instrumentation. Six patients were managed with Neurontin, and 1, with Valium. Two patients were offered removal of their implants, but their symptoms resolved before resection was performed. CONCLUSION: Pelvic fixation with Dunn-McCarthy instrumentation was associated with a 14% incidence of severe, unilateral neuropathic lower extremity pain.