Effects of vertebral shortening during corrective osteotomy for spinal deformity on spinal cord biomechanics and cerebrospinal fluid-anterior spinal artery fluid-structure interaction

Corrective osteotomy for severe spinal deformity requires vertebral shortening, but the safe degree of shortening remains uncertain. This study used fluid-structure interaction finite element analysis to investigate how graded vertebral shortening affects cerebrospinal fluid (CSF) dynamics and anterior spinal artery (ASA) perfusion. A three-dimensional T1-T12 model was reconstructed from computed tomography data obtained from a 16-year-old male with scoliosis.

Posterior vertebral column resection at T8/T9 was simulated in four conditions: no shortening and shortening by one-third, one-half, and two-thirds. Coupled CSF-dura and blood-vessel wall models were used to quantify pressure, wall shear stress, flow velocity, structural stress, and displacement. With shortening of up to one-half, CSF wall shear stress (~ 0.04 Pa) and velocity (~ 0.014 m/s) remained stable, whereas ASA luminal pressure and velocity declined gradually together with vessel-wall stress and displacement, indicating preserved hemodynamic compensation and mechanical unloading.

At two-thirds shortening, CSF wall shear stress (0.4998 Pa) and velocity (0.16009 m/s) increased by approximately 12-fold and 11-fold, respectively; dural stress increased by approximately 34%, whereas displacement increased by only 1.2%, demonstrating nonlinear stress-displacement decoupling. ASA luminal pressure, velocity, vessel-wall stress, and displacement also rebounded to their highest values. In this patient-specific model, shortening up to one-half was associated with relative stability of CSF dynamics and progressive vascular unloading, whereas two-thirds shortening produced marked nonlinear changes in CSF and ASA-related biomechanical variables.

These findings suggest a model-derived biomechanical transition between one-half and two-thirds shortening; however, this transition should not be interpreted as a clinically validated safety threshold. Sixth Affiliated Hospital of Xinjiang Medical University, Xinjiang, China Alimujiang Yusufu, Abudula Abulaiti, Abuduwupuer Haibier & Yuan Ma Spinal Surgery Research Institute of Xinjiang Uygur Autonomous Region, Xinjiang, China The authors declare no competing interests. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Below is the link to the electronic supplementary material. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it.

The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.