Subjects
All subjects participating in the study were pilot candidates who came to obtain a medical report to become a pilot. The lumbosacral vertebra roentgenogram studies of 633 candidates who applied to the outpatient clinic of our hospital between June 2018 and August 2018 were retrospectively analyzed. Then, anatomically normal, sacralized or lumbarized sacral vertebrae were compared using these examinations.
Imaging methods
Lumbosacral vertebra roentgenographies of all cases were evaluated. It was confirmed by the relevant radiology unit that the lumbosacral region was taken in the supine position for anteroposterior radiography and in the lateral position without flexion or extension for lateral radiography, and the position of the spine was placed in the middle of the table. It was learned that the patient was supported with radiolucent pillows from the sides to ensure that the spinal column was parallel to the table, the middle part of the detector was adjusted 6 cm above the iliac projection in the digital x-ray machine, and the procedure was performed as a standard procedure with the arms on both sides of the head and extended forward. We were informed that gonad protectors were used in male patients and the distance between the film and the x-ray tube was 100 cm. The L5 and S1 vertebrae were verified by an independent-blind radiologist with 18 years of experience in radiology.
All cases were divided into 3 groups by the radiologist. According to the criteria determined in the separated cases, the normal group (control group), sacralization group (study group 1) and lumbalization group (study group 2) were determined.
A new index (formula) was created to determine sacralization or lumbalization. For this purpose, it was investigated to create a simple formula by measuring the angles and distances between the simple lines we drew in accordance with the sacral anatomy, and whether there is a difference between sacralized and lumbarized spine.
Measurement methods
Anteroposterior and lateral radiographs of the vertebrae of all patients were obtained using standard techniques. Radiographic examination and morphometric measurements were made with the picture archiving and communication system (PACS Extreme, Ankara, Turkey). Arch and vertebral angle distance were calculated and measured on lateral radiography. Lateral projections were used as reference standards. “Anterior Translational Arch (ATA1)” as metrological measurement and “Anterior Translational Angle (ATA2)” as angle were performed.
Radiographs were initially reviewed for vertebral characterization and enumeration. The sum of cervical, thoracic, and lumbar segments above the sacrum was calculated as the total number of vertebrae. The first seven vertebrae were counted as cervical, twelve vertebrae as thoracic, and the vertebrae below the thoracic vertebra as lumbar vertebra. The first lumbar vertebra was taken as L1 vertebra. The fifth lumbar vertebra, showing the features of the adjacent sacral segment, was called sacralization. Similarly, the first sacral vertebra showing features of the adjacent lumbar segment was called lumbalization.
a) Measurement method of the ATA1
The method used for distance measurement (ATA1) is as shown in Figure 1a. The distance between the midpoint (blue line) of the line connecting the anterior aspects of the upper end of the first sacral vertebra and the lower end of the last sacral vertebra and the anterior direction of the sacral vertebral slope was called the ATA1 distance (yellow line).
b) Measurement method of the ATA 2
The method used to measure the angle (ATA2) is shown in Figure 1b. Initially, a transverse line was drawn through the upper surface of the first sacral vertebra (S1) to determine the midpoint (red line) of the anteroposterior length of S1. Next, a line was drawn (green line) connecting the midpoint of the anteroposterior length of S1 with the anterior face of the lower end of the last sacral vertebra. The angle between the blue line and the green line was named as ATA2 angle.
Statistical analysis
Statistical analysis was done by a professional statistician. In the analysis of the data, PSPP (PSPP is free software. It can redistribute and / or modify it according to the provisions of the GNU General Public License issued by the Free Software Foundation. Version 3 of the license and Microsoft Excel computer programs were used. As statistical method in the analysis of the data, descriptive analysis (mean, standard deviation, range) are given in Tables 1, 2, 3. ANOVA (Post Hoc: Bonferroni) was used to compare the three groups and to evaluate the difference between the distance and angle values between the groups. Logistic regression was used for risk analysis. Confidence interval and p <0.05 significance level Receiver Operating Characteristic (ROC) analysis test was applied to determine the cut-off point for the study groups compared to the control group for distance and angle values.