Clipping Test of a Radiculomedullary Artery During Resection of a Dorsal Spinal Meningioma.

Arterial supply of the spinal cord is derived from the anterior spinal artery (ASA) and 2 posterior spinal arteries. In the thoracic spine, a few segmental arteries give origins to radiculomedullary arteries (RMAs) that supply the ASA and posterior spinal arteries.1 In the lower thoracic spine, the supply is provided by the Adamkiewicz artery. Spinal meningiomas may be embedded and/or supplied by the RMA, which may be sacrificed to obtain complete resection. Safety of the thoracic RMA occlusion is controversial,2 especially if the Adamkiewicz artery is involved.3 Somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEP) are proposed to detect spinal cord ischemia.4 The RMA supplies the anterior spinal cord, and MEPs seem to be more sensitive than SSEPs to test RMA occlusion.2 SSEP and MEP monitoring during temporary occlusion has been described and significantly changes at 2 and 7 minutes of occlusion.5-8 Safe occlusion with unchanged MEPs after 10-minute temporary occlusion of 32 segmental arteries was reported by Salame et al.9 We intraoperatively discovered an anterior T10 RMA supplying the adjacent meningioma (Video 1). We temporary clipped the artery for 8 minutes. MEPs were recorded before clipping and every 2 minutes. No changes were observed, and the artery was sacrificed. RMA or segmental artery ligature may be required and is frequently performed in deformity, oncologic, and vascular spine surgery. The clipping test with MEP monitoring is a useful and simple intraoperative tool to identify the critical afferents of the ASA. It doesn't require planification or supplementary materials. Further study might be performed to validate the technique.