48. A comparative study of the sagittal and coronal balance of the spine measured using a 3D full-body scanner and whole spine X-ray

Abstract

BACKGROUND CONTEXT

Spinal balance analysis is critical to the diagnosis and treatment of ASD, and radiography is the current gold standard. Radiation-free 3D full body scanner has been developed to overcome drawbacks of X-ray such as radiation exposure and limited reflection of actual daily activity.

PURPOSE

This study aims to develop a spinal balance analysis system based on the 3D full body scanner and compare it to X-ray parameters. This study aims to develop a spinal balance analysis system based on the 3D full body scanner and compare it to X-ray parameters.

STUDY DESIGN/SETTING

This study is a prospective observational study.

PATIENT SAMPLE

Ninety-seven participants recruited from our hospital patient clinic and underwent both 3D body scanning and whole spine X-rays. The participants completed the clinical questionnaire and body composition analyses.

OUTCOME MEASURES

The 3D scanner spinal balance parameters were defined as the angles between two points relative to the plumb line, the horizontal distances between two points, the angle between three points, and shoulder gradient. The X-ray spinal balance parameters were C2-7 sagittal vertical axis (SVA), T1 slope, sagittal vertical axis (SVA), odontoid hip axis angle (ODHA), clavicle angle, T1 coronal tilt, lumbar lordosis, sacral slope, and pelvic incidence-lumbar lordosis (PI-LL) mismatch. Body composition scores were body mass index (BMI), percentage body fat (PBF), and skeletal muscle index (SMI). Patient-reported clinical symptoms included the visual analog scale (VAS, 0-10) score of low back pain and the modified Oswestry Disability Index (mODI, 0-45).

METHODS

Five inflection points were automatically labeled by AI from the 3D scanner data and spinal balance parameters were subsequently calculated. Correlation analysis was conducted to compare spinal balance parameters obtained from a 3D full-body scanner and X-ray imaging. The same analysis was also conducted to identify correlation between spinal parameters and clinical symptoms. Partial correlation analysis and multiple regression analysis were conducted to determine the impact of body composition on spinal balance.

RESULTS

The study indicated statistically significant correlations between sagittal parameters of X-ray and 3D body scanner. The correlation coefficient of dAB_hor (horizontal distance between ear and shoulder in the sagittal plane) and C2-C7 SVA was 0.478 (p-value <0.001). The correlation coefficient between aAC_sag (sagittal angle of ear-hip from the plumb line) and ODHA was 0.336 (p <0.001). For coronal spinal balance, the shoulder gradient calculated by AI was compared to the clavicle angle from the X-ray, resulting in a correlation coefficient of 0.373 (p <0.001). In contrast, the differences between 3D scanning and radiography were unaffected by body composition. Additionally, there was correlation between clinical symptoms and spinal parameters. The ODI score had a statistically significant correlation with both aBCD(shoulder-hip-knee angle) and aCDE(hip-knee-ankle angle) with correlation coefficients of -0.205 (p-value 0.044) and 0.245 (p-value 0.015), respectively. The correlation between the cervical spinal parameters was found to be stronger than the thoracolumbar parameters due to the differences in posture, time, and landmarks in the two exams conducted. The clinical symptoms were correlated with aBCD and aCDE due to the compensatory knee flexion for the thoracolumbar kyphosis.

CONCLUSIONS

Our study highlights that the spinal balance analysis, based on 3D full-body scanner, has a statistical correlation with X-ray. Furthermore, clinical symptoms were correlated with hip flexion and knee flexion parameters obtained from the 3D scanner attributed to the compensatory motion. This preliminary study sets the foundation for the application of radiation-free 3D body scanner in the spinal balance analysis.

FDA Device/Drug Status

This abstract does not discuss or include any applicable devices or drugs.