Observational Study
Copyright ©The Author(s) 2025. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Orthop. Aug 18, 2025; 16(8): 108161
Published online Aug 18, 2025. doi: 10.5312/wjo.v16.i8.108161
Factors that influence long term instrumentation stability in patients with unstable thoracolumbar injuries
Andrey E Bokov, Svetlana Y Kalinina, Daria A Kulagina, Kseniia S Lopyrina, Vladimir V Klinshov, Anatolii A Bulkin
Andrey E Bokov, Svetlana Y Kalinina, Daria A Kulagina, Kseniia S Lopyrina, Anatolii A Bulkin, Department of Neurosurgery, Federal State Budgetary Educational Institution of Higher Education, Privolzhsky Research Medical University of the Ministry of Health of the Russian Federation, Nizhniy Novgorod 603115, Russia
Vladimir V Klinshov, Anatolii A Bulkin, Department of Fundamental Mathematics, National Research University Higher School of Economics, Nizhniy Novgorod 603155, Russia
Co-corresponding authors: Andrey E Bokov and Anatolii A Bulkin.
Author contributions: Bokov AE was the guarantor and designed the study and data; Klinshov VV participated in data acquisition and analysis; Klinshov VV, Kalinina SY, Kulagina DA, and Bulkin AA participated in data interpretation; Klinshov VV, Kalinina SY, Kulagina DA, and Lopyrina KS drafted the initial manuscript; Lopyrina KS performed data collection; Bulkin AA critically revised the article for important intellectual content; Bokov AE and Bulkin AA contributed equally to this article, they are the co-corresponding authors of this manuscript; all authors thoroughly reviewed and endorsed the final manuscript.
Supported by AI For Spinal Surgery Planning and Results Assessment Project under the “Priority 2030” Academic Leadership Initiative, No. 6.18-01/240724-15.
Institutional review board statement: This study was approved by the Medical Ethics Committee of the Privolzhskiy Research Medical University, approval No. 19, 12/09/2022.
Informed consent statement: All study participants or their legal guardian provided informed written consent about personal and medical data collection prior to study enrollment.
Conflict-of-interest statement: The authors report no relevant conflicts of interest for this article.
STROBE statement: The authors have read the STROBE Statement-checklist of items, and the manuscript was prepared and revised according to the STROBE Statement-checklist of items.
Data sharing statement: All data collected during the study are available from the corresponding author by request at andrei_bokov@mail.ru.
Open Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Andrey E Bokov, MD, PhD, Department of Neurosurgery, Federal State Budgetary Educational Institution of Higher Education, Privolzhsky Research Medical University of the Ministry of Health of the Russian Federation, Verkhnevolzhskaya Naberezhnaya 18, Nizhniy Novgorod 603115, Russia. andrei_bokov@mail.ru
Received: April 8, 2025
Revised: April 30, 2025
Accepted: July 1, 2025
Published online: August 18, 2025
Processing time: 123 Days and 14.7 Hours
Abstract
BACKGROUND

Pedicle screw fixation is frequently used to treat unstable thoracolumbar injuries; however, the rate of instrumentation failure remains considerable. The primary contributing factor leading to instrumentation failure is poor bone quality. On the other hand, some evidence suggests that surgical tactics can influence long-term instrumentation stability.

AIM

To assess factors that influence the stability of spinal instrumentation in patients with thoracolumbar injuries.

METHODS

This study is a non-randomized single center ambispective evaluation of 204 consecutive patients (117 men; 87 women) with unstable thoracolumbar injuries. All patients underwent either stand-alone or combined with anterior column reconstruction instrumentation. In cases with spinal cord and nerve root injuries, either posterior or anterior decompression were performed. Patients with pedicle screw loosening were identified via computed tomography imaging. Out of those, cases with clinically significant instrumentation failure were registered.

RESULTS

The rate of pedicle screw loosening detected by computed tomography was inversely correlated with bone radiodensity figures and an increased association with the number of instrumented levels, residual kyphotic deformity, laminectomy, and lumbosacral fixation. Intermediate screws and anterior reconstruction were associated with a clinically relevant decreased risk of pedicle screw loosening development. Either complete or partial posterior fusion within instrumented levels was capable of decreasing instrumentation failure risk, while extensive decompression with laminectomy and at least one-level total facetectomy were associated with an increased risk of instrumentation failure. Anterior decompression does not have a negative impact on instrumentation stability.

CONCLUSION

Intermediate screws, anterior reconstruction and posterior tension band preservation are associated with decreased rates of instrumentation instability development. Posterior fusion is beneficial in terms of instrumentation failure prevention.

Keywords: Instrumentation stability; Unstable thoracolumbar injuries; Pedicle screw loosening; Anterior reconstruction; Posterior decompression

Core Tip: A single center ambispective non-randomized evaluation of 204 consecutive patients with unstable thoracolumbar injuries treated pedicle screw fixation. Patients with pedicle screw loosening were identified using computed tomography, and those cases with clinically significant complications were registered. Multivariate logistic regression and general discriminant analysis suggest that the rate of pedicle screw loosening depends on bone radiodensity, length of fixation, type and extensiveness of decompression. Auxiliary posterior fusion, intermediate screw and anterior reconstruction can provide a clinically significant decrease in complication rate.