Simulating upright cervical lordosis in the supine position

Abstract

Cervical alignment or lordosis evolution is still attained by direct radiography in standing position because an ideal cervical curvature is essential to maintain a horizontal gaze with minimal energy consumption. However, upright cervical lordosis changes in supine position. Anterior fusion surgery and more sophisticated radiological examinations, such as Computed Tomography (CT) and Magnetic Resonance Imaging (MRI), are performed in lying position. Therefore, if upright cervical alignment can be simulated in the supine position, true (upright) cervical lordosis can be demonstrated on CT and MRI and also a more proper anterior cervical fusion can be performed in operation with better surgical outcomes. Forty-nine (49) adult patients underwent radiological examinations, including upright cervical radiography and three session of supine MRI in different positions. MRI was performed in (1) conventional neutral supine position, (2) supine position with a 5-cm-high pillow, and (3) supine position with a 10-cm-high pillow under the shoulders. MRI results were analyzed. Wilcoxon, Kolmogorov-Smirnov, and Spearman correlation tests were used to analyze MRI the validity in compared with those of cervical radiography. Cervical lordosis (C2-C7 Cobb angle) of the radiography group was similar to that of supine MRI group using a 5-cm-high pillow, and they have a strong correlation. The T-1 slope from radiography group was similar to and correlated with that of supine MRI groups with both pillows. Cranial tilt measurements of radiography group were different but correlated with the MRI group using a 5-cm-high pillow. Simulating upright cervical lordosis in the supine position is possible by adding a 5-cm-high pillow under the shoulders of the patients. This simulation reduces the need for direct radiography. Anterior cervical fusion surgery performed in this position can provide better surgical results.