Spine3d and Its Reliability in Evalution of Deformity in Patients with Idiopathic Scoliolic

Mazza Daniele^1,3*, Gagliardo Salvatore², Barbarino Manfredi¹, Bolle Gabriele¹, Emanuele Giovanni¹, De Carli Angelo², Santoriello Vincenzo^3, Febbi Massimiliano^4,5

¹Istituto Dermopatico dell’Immacolata, Via dei Monti di Creta, 104, 00167 Roma RM, Italy
²Orthopaedic Unit and Kirk Kilgour Sports Injury Center, S. Andrea Hospital, University of Rome “Sapienza”, Via di Grottarossa 1035-1039, 00189, Rome, Italy
³Catholic University, Milan, Italy
⁴ASOMI College of Sciences, School of Medicine, Head Office: Navi Building, Pantar Road, LJA 2021, Malta, Educational Campus: Giorgio Mitrovich Street, Pembroke, Malta, School of Medicine: Triq Is Sirk 121, Swieqi, Malta
⁵Laboratory for Rehabilitation Medicine and Sport (LARMS), Rome, Italy

*Correspondence author: Mazza Daniele, Istituto Dermopatico dell’Immacolata, Via dei Monti di Creta, 104, 00167 Roma RM, Italy and ASOMI College of Sciences, School of Medicine, Head Office: Navi Building, Pantar Road, LJA 2021, Malta, Educational Campus: Giorgio Mitrovich Street, Pembroke, Malta, School of Medicine: Triq Is Sirk 121, Swieqi, Malta; Email: [email protected]

Published Date: 03-12-2024

Copyright© 2024 by Mazza D, et al. All rights reserved. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 

Abstract

Idiopathic scoliosis is a complicated orthopedic disorder marked by a side-to-side curvature of the spine, the cause of which is unknown and it predominantly affects children and adolescents. The Cobb angle is the conventional technique for evaluating the severity of scoliosis through X-rays; however, it has limitations, including inter and intra-observer variability that can compromise measurement accuracy. LiDAR (Light Detection and Ranging) technology presents a promising radiation-free alternative by generating accurate three-dimensional models of the body’s anatomy through the use of laser pulses to measure distances.

The aim of this study is to assess the accuracy and reproducibility of the Spine3D system as compared to traditional radiographs.

Conducted at Sant’Andrea University Hospital in Rome from September 2022 to 2024, the study involved patients aged 10 to 18 diagnosed with idiopathic scoliosis. Participants’ weight, height and body mass index (BMI) were recorded and a detailed evaluation was conducted using the Spine3D system, which employs infrared cameras to assess spinal alignment and X-rays.

The study included 26 adolescents, showing no significant difference between Cobb angles measured via X-rays (30.1 degrees) and Spine3D (29.9 degrees). Intra-observer reliability was high for both methods, with Spine3D demonstrating superior consistency. Differences were observed in measurements such as lordotic angles, attributed to variations in postural stance.

The Spine3D system for measuring the Cobb angle proved to be reliable and efficient, suggesting it could be integrated into clinical practice alongside radiographic monitoring. Future studies are necessary to further explore the clinical application of Spine3D in tracking spinal curvature throughout treatment.

Keywords: Idiopathic Scoliosis; Spine3D; X-rays; LIDAR

Introduction

Idiopathic scoliosis is among the most intricate orthopedic disorders, marked by a sideways curvature of the spine that lacks an identifiable cause. It mainly impacts children and teenagers, although it can manifest at any growth stage [1]. The Cobb angle is a frequently employed technique for assessing the severity of scoliosis through X-rays, serving as a crucial standardized measure for evaluating and managing spinal curvature [2]. However, measuring the Cobb angle has its drawbacks, particularly inter- and intra-observer variability which may compromise measurement precision. Many factors could affect measurements up to 5 degrees [3,4].

LiDAR (Light Detection and Ranging) technology is a remote sensing method that uses laser light to measure distances, enabling the creation of precise three-dimensional models of objects or surfaces [5]. In scoliosis assessment, LiDAR presents significant improvements over conventional methods like X-rays, notably in safety, as it does not involve ionizing radiation and in its ability to accurately depict the body’s three-dimensional anatomy. In this regard, Spine3D (Sensor Medica, Guidonia Montecelio, Italy) is an innovative device designed for spine evaluation and rotation analysis [6].

Employing LiDAR for scoliosis assessment involves sending laser pulses from a scanning unit. These pulses reflect off the surfaces of the patient’s body and return to the sensor. By measuring the time taken for the pulses to return, the LiDAR system can accurately calculate distances, resulting in a three-dimensional model of the analyzed surface.

Employing LiDAR for scoliosis assessment involves sending laser pulses from a scanning unit. These pulses reflect off the surfaces of the patient’s body and return to the sensor. By measuring the time taken for the pulses to return, the LiDAR system can accurately calculate distances, resulting in a three-dimensional model of the analyzed surface.

Methodology

This study was conducted at Sant’Andrea University Hospital in Rome, within the Orthopedics and Traumatology Department, from September 2022 to September 2024. It included patients aged 10 to 18 years diagnosed with idiopathic scoliosis, with Cobb angles between 10° and 45°. Excluded were individuals with secondary scoliosis, a history of vertebral fractures or pre-existing cardiovascular or metabolic disorders such as obesity. Informed consent was obtained both verbally and in writing from parents or legal guardians and the adolescents [7].

Body weight was recorded with participants barefoot and in light clothing, standing upright on a Seca scale platform (Hamburg, Germany) with arms at their sides. Height was measured using a Harpenden stadiometer (Holtain Ltd., Cross-Well, UK), ensuring subjects stood upright and without shoes, with their heads positioned horizontally. Two measurements were taken for each parameter, with a third taken if there was a discrepancy of 500 g in weight or 0.5 cm in height. The final anthropometric parameters were calculated by averaging the two closest measurements. The Body Mass Index (BMI) was also determined using the formula: BMI = weight in kilograms / (height in meters x height in meters).

SPINE3D

The Spine3D® system (Fig. 1) is a cutting-edge, non-invasive three-dimensional optoelectronic detection tool (Kinect) designed for precise evaluation of vertebral alignment. It features a single vertical aluminum panel measuring 165 × 63 × 76 cm and is equipped with a 27″ touchscreen monitor that offers a 1920 x 1080 resolution at 60 Hz (2.1 megapixel Full HD) in a vertical 16:9 orientation, with dimensions of 597.6 x 336.15 mm (23.5 x 13.2″).

SPINE3D

The Spine3D® system (Fig. 1) is a cutting-edge, non-invasive three-dimensional optoelectronic detection tool (Kinect) designed for precise evaluation of vertebral alignment. It features a single vertical aluminum panel measuring 165 × 63 × 76 cm and is equipped with a 27″ touchscreen monitor that offers a 1920 x 1080 resolution at 60 Hz (2.1 megapixel Full HD) in a vertical 16:9 orientation, with dimensions of 597.6 x 336.15 mm (23.5 x 13.2″).

The internal software employs a class I infrared light beam to capture an image of the back and assess the difference between the projected and received images, which is displayed on the monitor. The device identifies anatomical surface irregularities, such as prominent vertebrae, shoulders and lumbar dimples and mathematically analyzes this data to create a three-dimensional model of the spine with a resolution of 1 mm.

Measurements were conducted in the afternoon within a consistent clinical environment at a temperature of 21°C. Participants stood barefoot on a stabilometric platform in a quiet, upright position with their backs exposed, facing the Spine3D system, positioned roughly 110 cm away. Two operators performed measurements with a 5-minute interval between them.

Once the participant was properly positioned, the examination began, requiring the individual to remain still for 10 seconds for image acquisition to finish. The Spine3D system identifies various anatomical landmarks during this process (Fig. 2):

VP (Vertebra Prominent)**: Identifies the prominent vertebra, which is C7.

SL (Left Shoulder) and SR (Right Shoulder): Indicate the left and right shoulder acromions, respectively.

DL (Left Dimple) and DR (Right Dimple): Refer to the left and right lumbar dimples, respectively, which represent the posterior iliac crests of the pelvis.

SP (Sacral Prominent): Marks the sacral prominence, representing S2.

Upon of the acquisition, the software automatically generates a comprehensive report for the patient, detailing all relevant spine values and indices. The measurements included in this study are: Kyphotic angle, Lordotic angle, Shoulder disparity, Pelvic tilt, Curvature angle of the spine.

These parameters are illustrated in Fig. 3,4.

Kyphotic Angle (KA): This angle is determined by the tangents to the surface at the cervico-thoracic inversion point (ICT) and the thoraco-lumbar inversion point (ITL). It is measured in degrees.

Lordotic Angle (LA): This angle is defined by the tangents to the surface at the thoraco-lumbar inversion point (ITL) and the lumbo-sacral inversion point (ILS). It is also expressed in degrees.

Shoulder asymmetry is evaluated by measuring the distance between the horizontal axis that passes through the left acromion (SL) and the horizontal axis that passes through the right acromion (SR). This measurement is expressed in millimeters (mm).

Pelvic tilt is assessed by the distance between the horizontal axis that passes through the left dimple (DL) and the horizontal axis that passes through the right dimple (DR), also expressed in millimeters (mm). The curvature angle is defined as the angle formed by the two tangents that extend above the upper end vertebral body and below the lower end vertebral body. This angle is expressed in degrees.

Shoulder asymmetry is evaluated by measuring the distance between the horizontal axis that passes through the left acromion (SL) and the horizontal axis that passes through the right acromion (SR). This measurement is expressed in millimeters (mm).

Pelvic tilt is assessed by the distance between the horizontal axis that passes through the left dimple (DL) and the horizontal axis that passes through the right dimple (DR), also expressed in millimeters (mm). The curvature angle is defined as the angle formed by the two tangents that extend above the upper end vertebral body and below the lower end vertebral body. This angle is expressed in degrees.

The LL radiographic exam was also conducted with the patient upright, arms wrapped around the head and knees slightly bent to maintain the position. The centering is performed with the perpendicular incident beam directed at the iliac crest. The radiographic measurements considered in the study include: lumbar lordotic angle, thoracic kyphotic angle, coracoid height, pelvic tilt and Cobb angle.

The Lumbar Lordotic Angle (LLA) is the angle measured on lateral radiographs, formed by the intersection of the line tangent to the upper portion of the first lumbar vertebra and the line passing through the upper edge of the sacral vertebra. The measurement is normally between 51° and 53° (Fig. 5).

The kyphosis angle is formed between the upper limit of T1 and the lower limit of T12 and can vary between 20-25° and 40-45° (Fig. 6). The difference in coracoid height indicates shoulder asymmetry and is measured as the height difference between the horizontal lines passing through the upper margin of each coracoid process. It is expressed in millimeters (mm) (Fig. 7). Pelvic tilt is assessed by measuring the height difference of the iliac crests and is determined as the height difference between the horizontal lines passing through the upper margin of each iliac crest. It is expressed in millimeters (mm) (Fig.8).

The Cobb measurement method (2), recommended by the Terminology Committee of the Scoliosis Research Society, consists of three steps: (1) locate the upper end vertebra; (2) locate the lower end vertebra; (3) draw lines perpendicular to the upper surface of the upper end vertebra and the lower surface of the lower end vertebra. The angle of deviation of these perpendicular lines from a straight line is the curve angle. If the vertebral endplates are obscured, the pedicles can be used instead. The end vertebra of the curve is the one most tilted towards the concavity of the curve to be measured (Fig. 9).

All measurements were performed by two orthopedic surgeons (DM and SG), by uploading the images to Horos® (Horos project), an open source program that transforms the computer into a DICOM workstation for processing and visualizing medical images. Measurements were conducted twice for all patients by both orthopedics and the average was considered for statistical calculations.

Figure 1: Spine3D.

Figure 2: Registration of anatomical landmarks during image acquisition: VP, SL, SR, DL, DR, SP.

Figure 3: Measurements performed by Spine3D in the sagittal projection of the spine.

Figure 4: Measurements performed by Spine3D in the coronal projection of the spine.

Figure 5: Radiographic measurement of the lumbar lordotic angle.

Figure 6: Radiographic measurement of the thoracic kyphosis angle.

Figure 7: Radiographic measurement of shoulder asymmetry.

Figure 8: Radiographic measurement of pelvic tilt.

Figure 9: Radiographic measurement of Cobb Angle.

Statistical Analysis

All data were expressed as mean, followed by ± Standard Deviation (SD), with the range of measurements in parentheses. Intra-observer differences in the two measurements of the Cobb angle on the radiographs and the two measurements using Spine3D were considered. The frequency and cumulative percentage distribution of the intra-observer differences were recorded. The Intraclass Correlation Coefficient (ICC) was used to analyze the reliability of the measurements. ICC values can range from 0 to 1, with a higher value indicating greater reliability. An ICC below 0.40 is considered poor, 0.40 to 0.59 fair, 0.60 to 0.74 good and 0.75 to 1.00 excellent. A paired t-test was used to compare results between the two measurement methods. A result is considered statistically significant with a p-value < 0.05. Statistical analyses were performed using SPSS 13.0 software (SPSS Inc., Chicago, IL).

Results

The study initially included 29 adolescents diagnosed with idiopathic scoliosis; however, 2 were excluded due to behavioral disorders and 1 did not complete the follow-up. Consequently, the final sample consisted of 26 adolescents, with their demographic data detailed in Table 1.

Table 1: Demographics data.

The average Cobb angle measured on the X-rays was 30.1 degrees (range, 18-56 degrees) and 29.9 degrees (range, 17-58 degrees) when measured with Spine3D. This measurement is not statistically significant (P=0.89). The average Cobb angles measured in each method, the Standard Deviation (SD) between the two measurements and the 95% confidence interval for the difference between the two measurements are summarized in Tables 2 and 3.

Table 2: Summary of data for the manual measurement.

Table 3: Summary of data for the Spine3D measurement.

The overall intra-observer variability was 0.955 and the overall inter-observer variability was 0.936 for the X-ray measurements, while the intra-observer variability was 0.985 and the inter-observer variability was 0.956 for Spine3D. Both intra-observer and inter-observer ICCs were excellent in both types of measurements and between the two observers (Table 4). Both the intra-observer ICC and the inter-observer ICC were better in the Spine3D measurements compared to the manual measurement.

Table 4: ICC indicates intraclass correlation coefficients.

All other measurements are outlined in Table 5 and none proved to be statistically significant.

Table 5: The manual measurement is expressed as the average of the two measurements from the two operators. The Spine3D measurement is expressed as the average of the two different measurements.

Discussion

The study highlights that Spine3D is a valid and reproducible method, comparing it to the digital measurements of the Cobb angle performed on patient X-rays. The hypothesis of the study was that the LiDAR method of Spine3D can be considered a reliable method in the assessment of idiopathic scoliosis and this was confirmed by the results.

While a low-dose imaging solution, like the EOS Imaging System (EOS Imaging, Paris, France), has recently been introduced, utilizing radiation-free methods to monitor scoliosis and its progression remains highly beneficial [8-10]. Several non-invasive systems based on dorsal surface topography have been developed as alternatives to traditional radiography, including: Moiré projection, Laser scanning, Electromagnetic topography, Ultrasound imaging, Rasterstereography [11-25].

These systems, which utilize the reconstruction of the body’s back surface, offer indirect measurements of spinal deformities. While they do not directly assess the internal structure of the spine and are unable to definitively diagnose the degree of scoliosis, the integration of Artificial Intelligence (AI) has enabled the analysis of a larger cohort of subjects to predict spinal anatomical conformation. Consequently, these techniques can serve as cost-effective and efficient methods for the initial screening of spinal deformities.

Encouraging results have been reported in terms of reliability (the repetition of a measure) and validity (the measure accurately corresponding to reality). This study highlights an overall intra-observer variability of 0.955 and an overall inter-observer variability of 0.936 for X-ray measurements, while the intra-observer variability was 0.985 and the inter-observer variability was 0.956 for Spine3D. Both intra-observer and inter-observer ICCs were excellent for both types of measurements and between the two observers, yet better in Spine3D measurements compared to manual measurement. Standard X-ray measurements using a goniometer inherently show different values. Carman, et al., and Morrissy, et al., found that the inter- and intra-observer variations in Cobb angle measurements average 5-7 degrees [26,27]. However, this study found similar reproducibility values among observers and in their repeat measurements.

The average measurements performed by the operators and by Spine3D on the kyphotic angle, shoulder level difference and pelvic level difference did not show statistically significant differences. However, regarding the lordotic angle, the radiographic measurements showed an average angle of 49.1 ± 2.8, while those performed with Spine3D showed an average angle of 38.41 ± 3.2 [32-54]. This difference was statistically significant. This discrepancy is likely due to the patient’s postural stance and the presence of different somatotypes among individuals, which may have led to incorrect identification of the sacral landmarks (DL, DR, SP), thus altering the measurement.

This study represents the first documented comparison between a LiDAR method and standard measurements in idiopathic scoliosis, yielding encouraging results. However, it has certain limitations. The sample size is relatively small due to strict inclusion criteria and patients with more severe curvatures may be unable to stand during testing, often relating to secondary conditions. Additionally, the study did not account for other radiographic parameters that could not be compared with the Spine3D measurements. Furthermore, monitoring scoliosis curvature over time was not conducted, as it would have required additional follow-up.

Conclusion

In conclusion, measuring the Cobb angle with Spine3D has shown remarkable reliability and efficiency. It is recommended to incorporate this method into clinical practice alongside traditional radiographic monitoring. Future research is necessary to assess the effectiveness of Spine3D in the clinical monitoring of spinal curvatures throughout treatment.

Conflict of Interests

The authors declare that they have no conflict of interest in this paper.

Funding
None

Authors’ Contributions

All authors contributed equally in this paper.

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Article Type

Research Article

Publication History

Accepted Date: 11-11-2024
Accepted Date: 26-11-2024
Published Date: 03-12-2024

Copyright© 2024 by Mazza D, et al. All rights reserved. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Citation: Mazza D, et al. Spine3d and Its Reliability in Evalution of Deformity in Patients with Idiopathic Scoliolic. J Ortho Sci Res. 2024;5(3):1-12.

Figure 1: Spine3D.

Figure 2: Registration of anatomical landmarks during image acquisition: VP, SL, SR, DL, DR, SP.

Figure 3: Measurements performed by Spine3D in the sagittal projection of the spine.

Figure 4: Measurements performed by Spine3D in the coronal projection of the spine.

Figure 5: Radiographic measurement of the lumbar lordotic angle.

Figure 6: Radiographic measurement of the thoracic kyphosis angle.

Figure 7: Radiographic measurement of shoulder asymmetry.

Figure 8: Radiographic measurement of pelvic tilt.

Figure 9: Radiographic measurement of Cobb Angle.