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The Optimal Screw Length of Lumbar Pedicle Screws during Minimally Invasive Surgery Fixation: A Computed Tomography-Guided Evaluation of 771 Screws

STUDY DESIGN: A retrospective study of radiographic parameters of patients who underwent lumbar spinal pedicle screw insertion. PURPOSE: The optimal length of pedicle screws is often determined by the lateral radiograph during minimally invasive surgery (MIS). Compared with open techniques, measurin...

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Autores principales: Chua, Min Jia, Siddiqui, Shiblee, Yu, Chun Sing, Nolan, Colum Patrick, Oh, Jacob Yoong-Leong
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Korean Society of Spine Surgery 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6894981/
https://www.ncbi.nlm.nih.gov/pubmed/31309769
http://dx.doi.org/10.31616/asj.2018.0276
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author Chua, Min Jia
Siddiqui, Shiblee
Yu, Chun Sing
Nolan, Colum Patrick
Oh, Jacob Yoong-Leong
author_facet Chua, Min Jia
Siddiqui, Shiblee
Yu, Chun Sing
Nolan, Colum Patrick
Oh, Jacob Yoong-Leong
author_sort Chua, Min Jia
collection PubMed
description STUDY DESIGN: A retrospective study of radiographic parameters of patients who underwent lumbar spinal pedicle screw insertion. PURPOSE: The optimal length of pedicle screws is often determined by the lateral radiograph during minimally invasive surgery (MIS). Compared with open techniques, measuring the precise length of screws or assessing the cortical breach is challenging. This study aims to ascertain the optimal pedicle screw lengths on intraoperative lateral radiographs for L1–L5. OVERVIEW OF LITERATURE: Research has revealed that optimal pedicle screw length is essential to optimize fixation, especially in osteoporotic patients; however, it must be balanced against unintentional breach of the anterior cortex, risking injury to adjacent neurovascular structures as demonstrated by case reports. METHODS: We reviewed intra- and postoperative computed tomography scans of 225 patients who underwent lumbar pedicle screw insertion to ascertain which of the inserted screws were ‘optimal screws.’ The corresponding lengths of these screws were analyzed on postoperative lateral radiographs to ascertain the ideal position that a screw should attain (expressed as a percentage of the entire vertebral body length). RESULTS: We reviewed 880 screws of which 771 were optimal screws. We noted a decreasing trend in average optimal percentages of insertion into the vertebral body for pedicle screws going from L1 (average=87.60%) to L5 (average=78.87%). The subgroup analysis revealed that there was an increasing percentage of screws directed in a straight trajectory from L1 to L5, compared to a medially directed trajectory. CONCLUSIONS: During MIS pedicle screw fixation, this study recommends that pedicle screws should not exceed 85% of the vertebral body length on the lateral view for L1, 80% for L2–L4, and 75% for L5; this will minimize the risk of anterior cortical breach yet maximize pedicle screw purchase for fixation stability.
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spelling pubmed-68949812019-12-11 The Optimal Screw Length of Lumbar Pedicle Screws during Minimally Invasive Surgery Fixation: A Computed Tomography-Guided Evaluation of 771 Screws Chua, Min Jia Siddiqui, Shiblee Yu, Chun Sing Nolan, Colum Patrick Oh, Jacob Yoong-Leong Asian Spine J Clinical Study STUDY DESIGN: A retrospective study of radiographic parameters of patients who underwent lumbar spinal pedicle screw insertion. PURPOSE: The optimal length of pedicle screws is often determined by the lateral radiograph during minimally invasive surgery (MIS). Compared with open techniques, measuring the precise length of screws or assessing the cortical breach is challenging. This study aims to ascertain the optimal pedicle screw lengths on intraoperative lateral radiographs for L1–L5. OVERVIEW OF LITERATURE: Research has revealed that optimal pedicle screw length is essential to optimize fixation, especially in osteoporotic patients; however, it must be balanced against unintentional breach of the anterior cortex, risking injury to adjacent neurovascular structures as demonstrated by case reports. METHODS: We reviewed intra- and postoperative computed tomography scans of 225 patients who underwent lumbar pedicle screw insertion to ascertain which of the inserted screws were ‘optimal screws.’ The corresponding lengths of these screws were analyzed on postoperative lateral radiographs to ascertain the ideal position that a screw should attain (expressed as a percentage of the entire vertebral body length). RESULTS: We reviewed 880 screws of which 771 were optimal screws. We noted a decreasing trend in average optimal percentages of insertion into the vertebral body for pedicle screws going from L1 (average=87.60%) to L5 (average=78.87%). The subgroup analysis revealed that there was an increasing percentage of screws directed in a straight trajectory from L1 to L5, compared to a medially directed trajectory. CONCLUSIONS: During MIS pedicle screw fixation, this study recommends that pedicle screws should not exceed 85% of the vertebral body length on the lateral view for L1, 80% for L2–L4, and 75% for L5; this will minimize the risk of anterior cortical breach yet maximize pedicle screw purchase for fixation stability. Korean Society of Spine Surgery 2019-12 2019-07-17 /pmc/articles/PMC6894981/ /pubmed/31309769 http://dx.doi.org/10.31616/asj.2018.0276 Text en Copyright © 2019 by Korean Society of Spine Surgery This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Clinical Study
Chua, Min Jia
Siddiqui, Shiblee
Yu, Chun Sing
Nolan, Colum Patrick
Oh, Jacob Yoong-Leong
The Optimal Screw Length of Lumbar Pedicle Screws during Minimally Invasive Surgery Fixation: A Computed Tomography-Guided Evaluation of 771 Screws
title The Optimal Screw Length of Lumbar Pedicle Screws during Minimally Invasive Surgery Fixation: A Computed Tomography-Guided Evaluation of 771 Screws
title_full The Optimal Screw Length of Lumbar Pedicle Screws during Minimally Invasive Surgery Fixation: A Computed Tomography-Guided Evaluation of 771 Screws
title_fullStr The Optimal Screw Length of Lumbar Pedicle Screws during Minimally Invasive Surgery Fixation: A Computed Tomography-Guided Evaluation of 771 Screws
title_full_unstemmed The Optimal Screw Length of Lumbar Pedicle Screws during Minimally Invasive Surgery Fixation: A Computed Tomography-Guided Evaluation of 771 Screws
title_short The Optimal Screw Length of Lumbar Pedicle Screws during Minimally Invasive Surgery Fixation: A Computed Tomography-Guided Evaluation of 771 Screws
title_sort optimal screw length of lumbar pedicle screws during minimally invasive surgery fixation: a computed tomography-guided evaluation of 771 screws
topic Clinical Study
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6894981/
https://www.ncbi.nlm.nih.gov/pubmed/31309769
http://dx.doi.org/10.31616/asj.2018.0276
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