Work

Magnetic Resonance Imaging Evaluation of Azygos Vein Deviation and Risk of Pedicle Screw Penetration in Thoracic Adolescent Idiopathic Scoliosis

Year: 2026

Type: article

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 0 o , and with the right at 180 o .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.

Source: Cureus

DOI: 10.7759/cureus.117170

Authors: Goutham B Chand, Binoy Sidhardhan, Ashok Ramakrishnan, Siddharth Babu Chand, Gayathry Santhosh, Meenakshi K G