Magnetic Resonance Imaging Evaluation of Azygos Vein Deviation and Risk of Pedicle Screw Penetration in Thoracic Adolescent Idiopathic Scoliosis
4 affiliations
- 1Department of Orthopaedics and Traumatology, Government Medical College, Thiruvananthapuram, Thiruvananthapuram, IND
- 2Department of Orthopaedics, Government Medical College, Thiruvananthapuram, Thiruvananthapuram, IND
- 3Orthopaedic Surgery, Bangalore Medical College and Research Institute, Bengaluru, IND
- 4General Surgery, Dr. D. Y. Patil Medical College, Hospital & Research Center, Map of Dr. D. Y. Patil Vidyapeeth, Pune Dr. D. Y. Patil Vidyapeeth, Pimpri, Pune, Pune, IND
Abstract
Objective
The primary objective was to compare the azygos vein-vertebral angle (AVVA) at T7-T10 in patients with thoracic adolescent idiopathic scoliosis (AIS) with previously published reference values. Secondary objectives were to determine the frequency of virtual pedicle screw trajectory-azygos vein intersection, compare AVVA between the concave and convex sides of the curve, and assess the association between AVVA and the main thoracic Cobb angle.Methodology
This was a cross-sectional study, which was carried out in the Department of Orthopaedics, Government Medical College, Thiruvananthapuram, over a period of one year. There were no normal individuals who did not have scoliosis in this research. To obtain good visibility of the azygos vein, images of the axial MRI at the T7-T10 levels, with the mid-vertebral body in the centre, were acquired. The AVVA is the angle formed between a line through the centre of the vertebral body perpendicular to the longitudinal axis of the vertebra and a line running through the centre of the vertebral body to the azygos vein. The azygos vein was in contact with the left at the AVVA 0o, and with the right at 180o. The virtual pathway of a pedicle screw was drawn on the pedicle axis on both sides, starting at the posterior cortical entrance point of the pedicle to the anterior vertebral cortex. This path was believed to be at risk of being damaged by the implantation of pedicle screws if this path was crossed. The proportion of azygos veins perceived to be at risk was calculated on both sides in relation to each patient.Results
Among the 41 subjects with thoracic AIS, a statistically significant deviation of the AVVA compared with previously reported normal reference values from the literature was observed at the T7, T8, T9, and T10 levels using a one-sample t-test (p = 0.00). These findings indicate substantial displacement of the azygos vein from its normal position in these patients. Risk assessment of pedicle screw penetration was performed using an independent t-test.Conclusion
The study demonstrates significant deviation of the azygos vein from its normal position in patients with thoracic AIS. This altered positioning increases the risk of injury to the azygos vein during pedicle screw fixation.
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BibTeX
@article{chand2026magnetic,
title = {{Magnetic Resonance Imaging Evaluation of Azygos Vein Deviation and Risk of Pedicle Screw Penetration in Thoracic Adolescent Idiopathic Scoliosis}},
author = {Goutham B Chand and Binoy Sidhardhan and Ashok Ramakrishnan and Siddharth Babu Chand and Gayathry Santhosh and Meenakshi K G},
journal = {Cureus},
year = {2026},
month = sep,
doi = {10.7759/cureus.117170},
url = {https://europepmc.org/article/PMC/PMC13719190},
note = {CC BY},
}
RIS
TY - JOUR
TI - Magnetic Resonance Imaging Evaluation of Azygos Vein Deviation and Risk of Pedicle Screw Penetration in Thoracic Adolescent Idiopathic Scoliosis
AU - Goutham B Chand
AU - Binoy Sidhardhan
AU - Ashok Ramakrishnan
AU - Siddharth Babu Chand
AU - Gayathry Santhosh
AU - Meenakshi K G
PY - 2026
DA - 2026/09/29
JO - Cureus
DO - 10.7759/cureus.117170
UR - https://europepmc.org/article/PMC/PMC13719190
AB - Objective The primary objective was to compare the azygos vein-vertebral angle (AVVA) at T7-T10 in patients with thoracic adolescent idiopathic scoliosis (AIS) with previously published reference values. Secondary objectives were to determine the frequency of virtual pedicle screw trajectory-azygos vein intersection, compare AVVA between the concave and convex sides of the curve, and assess the association between AVVA and the main thoracic Cobb angle.Methodology This was a cross-sectional study, which was carried out in the Department of Orthopaedics, Government Medical College, Thiruvananthapuram, over a period of one year. There were no normal individuals who did not have scoliosis in this research. To obtain good visibility of the azygos vein, images of the axial MRI at the T7-T10 levels, with the mid-vertebral body in the centre, were acquired. The AVVA is the angle formed between a line through the centre of the vertebral body perpendicular to the longitudinal axis of the vertebra and a line running through the centre of the vertebral body to the azygos vein. The azygos vein was in contact with the left at the AVVA 0o, and with the right at 180o. The virtual pathway of a pedicle screw was drawn on the pedicle axis on both sides, starting at the posterior cortical entrance point of the pedicle to the anterior vertebral cortex. This path was believed to be at risk of being damaged by the implantation of pedicle screws if this path was crossed. The proportion of azygos veins perceived to be at risk was calculated on both sides in relation to each patient.Results Among the 41 subjects with thoracic AIS, a statistically significant deviation of the AVVA compared with previously reported normal reference values from the literature was observed at the T7, T8, T9, and T10 levels using a one-sample t-test (p = 0.00). These findings indicate substantial displacement of the azygos vein from its normal position in these patients. Risk assessment of pedicle screw penetration was performed using an independent t-test.Conclusion The study demonstrates significant deviation of the azygos vein from its normal position in patients with thoracic AIS. This altered positioning increases the risk of injury to the azygos vein during pedicle screw fixation.
SN - 2168-8184
ER -