Novel Radiologic Parameter to Simulate Decompression Efficacy in Cervical Laminoplasty: The Magnetic Resonance Imaging Laminar Line.

Abstract

The goal of this study was to investigate the clinical value of magnetic resonance imaging (MRI) laminar line (LL)-simulated decompression for predicting the efficacy of cervical laminoplasty (CLP). Data of 60 patients who underwent CLP for cervical spondylotic myelopathy were retrospectively analyzed. LL was defined as the line between the anterior-inferior margin of the superior lamina and the anterior-superior margin of the inferior lamina at the decompression segment, and the anterior dural border to the midsagittal diameter of LL was measured. The diameter of the dural sac in the compression segment of preoperative MRI and the spinal canal of postoperative MRI were measured. The correlation between the actual spinal decompression degree and the MRI LL simulation decompression was compared. The modified Japanese Orthopedic Association score, visual analog scale score, and Neck Disability Index score were assessed. The midsagittal diameter of actual decompression and LL-simulated decompression was significantly increased compared with preoperative measurements. The predictive accuracy rate of the median sagittal diameter of LL was 91.7% (55/60) compared with the actual decompression effect. The mean and median diameters of LL-simulated decompression and actual decompression in 35 patients with C2-C7 Cobb ≥20° were wider than those in 20 patients with C2-C7 Cobb <20° (P < 0.05). The modified Japanese Orthopedic Association, visual analog scale, and Neck Disability Index scores were significantly higher at the final follow-up than preoperation (P < 0.001). The application of MRI LL-simulated decompression can predict radiological outcomes of spinal cord decompression and aid in the preoperative planning of CLP.