Is the Cervical Anterior Spinal Artery Compromised in Cervical Spondylotic Myelopathy Patients? Dual-Energy Computed Tomography Analysis of Cervical Anterior Spinal Artery

Abstract

Cervical myelopathy is a common, acquired cause of spinal cord dysfunction in older patients. It is postulated that a hypoxic or ischemic environment secondary to chronic spinal cord compression plays an important role in the pathogenesis of myelopathy. This study aims to use dual-energy computed tomography (DECT) to assess the altered blood flow to the spinal cord in patients with cervical spondylotic myelopathy (CSM). To our knowledge, this study is the first to use DECT in identifying comprised anterior spinal artery blood flow in patients with CSM. Fifty patients with single disc level CSM and 10 volunteers without CSM underwent DECT of the cervical spine to analyze and compare the ASA. The neurologic status of each patient was evaluated preoperatively and postoperatively at 5 days, 1 month, and 6 months using the Japanese Orthopedic Association (JOA) score. All the patients with CSM underwent single-level anterior cervical discectomy and fusion, and at postoperative day 5, each patient underwent repeated DECT. The anterior spinal artery before and after surgery was compared in patients with CSM. The blood flow in terms of iodine content at a specific region of interest was measured in the axial CT of the volunteers group and in the preoperative and postoperative axial CT of patients with CSM. Correlations between change in blood flow and clinical improvement at each follow-up point were analyzed statistically. Iodine content (100 mg/mL) was 14.2800 ± 1.89527 at the C3/C4 disc level, 14.8280 ± 1.83820 at the C4/C5 disc level, and 15.5000 ± 2.41048 at the C5/C6 level. In patients with CSM, the preoperative iodine content (100mg/mL) measured was10.2621 ± 2.37396 in C3/C4 disc-level compression, 12.1438 ± 1.63447 in C4/C5 disc-level compression, and 14.0620 ± 2.44390 in C5/C6 disc-level compression. Postoperative iodine content (100 mg/mL) measurement changed to 13.78 ± 2.77 for the C3/C4 disc level, 14.16 ± 1.90 for the C4/C5 disc level, and 15.14 ± 2.62 for the C5/C6 disc level. The JOA score was 13.650 preoperatively, 14.010 at 5 days postoperatively, 14.630 at 1 month postoperatively, and 15.000 at 6 months postoperatively. The 1- and 6-month correlation ratios between the JOA and change in blood flow were statistically significant, with an r value of 0.746 (P < 0.05) and 0.760 (P < 0.05), respectively. This study provided evidence for the benefit of DECT as a radiographic tool for identifying the compromised cervical anterior spinal artery in patients with CSM. We believe that DECT is the one of the best radiographic tools available to provide an objective screening tool to detect compromised blood flow in patients with CSM.