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Morphometric Evaluation of Occipital Condyles: Defining Optimal Trajectories and Safe Screw Lengths for Occipital Condyle-Based Occipitocervical Fixation in Indian Population
STUDY DESIGN: Computed tomographic (CT) morphometric analysis. PURPOSE: To assess the feasibility and safety of occipital condyle (OC)-based occipitocervical fixation (OCF) in Indians and to define anatomical zones and screw lengths for safe screw placement. OVERVIEW OF LITERATURE: Limitations of oc...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Korean Society of Spine Surgery
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5913011/ https://www.ncbi.nlm.nih.gov/pubmed/29713401 http://dx.doi.org/10.4184/asj.2018.12.2.214 |
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author | Bosco, Aju Venugopal, Prakash Shetty, Ajoy Prasad Shanmuganathan, Rajasekaran Kanna, Rishi Mugesh |
author_facet | Bosco, Aju Venugopal, Prakash Shetty, Ajoy Prasad Shanmuganathan, Rajasekaran Kanna, Rishi Mugesh |
author_sort | Bosco, Aju |
collection | PubMed |
description | STUDY DESIGN: Computed tomographic (CT) morphometric analysis. PURPOSE: To assess the feasibility and safety of occipital condyle (OC)-based occipitocervical fixation (OCF) in Indians and to define anatomical zones and screw lengths for safe screw placement. OVERVIEW OF LITERATURE: Limitations of occipital squama-based OCF has led to development of two novel OC-based OCF techniques. METHODS: Morphometric analysis was performed on the OCs of 70 Indian adults. The feasibility of placing a 3.5-mm-diameter screw into OCs was investigated. Safe trajectories and screw lengths for OC screws and C0–C1 transarticular screws without hypoglossal canal or atlantooccipital joint compromise were estimated. RESULTS: The average screw length and safe sagittal and medial angulations for OC screws were 19.9±2.3 mm, ≤6.4°±2.4° cranially, and 31.1°±3° medially, respectively. An OC screw could not be accommodated by 27% of the population. The safe sagittal angles and screw lengths for C0–C1 transarticular screw insertion (48.9°±5.7° cranial, 26.7±2.9 mm for junctional entry technique; 36.7°±4.6° cranial, 31.6±2.7 mm for caudal C1 arch entry technique, respectively) were significantly different than those in other populations. The risk of vertebral artery injury was high for the caudal C1 arch entry technique. Screw placement was uncertain in 48% of Indians due to the presence of aberrant anatomy. CONCLUSIONS: There were significant differences in the metrics of OC-based OCF between Indian and other populations. Because of the smaller occipital squama dimensions in Indians, OC-based OCF techniques may have a higher application rate and could be a viable alternative/salvage option in selected cases. Preoperative CT, including three-dimensional-CT-angiography (to delineate vertebral artery course), is imperative to avoid complications resulting from aberrant bony and vascular anatomy. Our data can serve as a valuable reference guide in placing these screws safely under fluoroscopic guidance. |
format | Online Article Text |
id | pubmed-5913011 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | Korean Society of Spine Surgery |
record_format | MEDLINE/PubMed |
spelling | pubmed-59130112018-04-30 Morphometric Evaluation of Occipital Condyles: Defining Optimal Trajectories and Safe Screw Lengths for Occipital Condyle-Based Occipitocervical Fixation in Indian Population Bosco, Aju Venugopal, Prakash Shetty, Ajoy Prasad Shanmuganathan, Rajasekaran Kanna, Rishi Mugesh Asian Spine J Clinical Study STUDY DESIGN: Computed tomographic (CT) morphometric analysis. PURPOSE: To assess the feasibility and safety of occipital condyle (OC)-based occipitocervical fixation (OCF) in Indians and to define anatomical zones and screw lengths for safe screw placement. OVERVIEW OF LITERATURE: Limitations of occipital squama-based OCF has led to development of two novel OC-based OCF techniques. METHODS: Morphometric analysis was performed on the OCs of 70 Indian adults. The feasibility of placing a 3.5-mm-diameter screw into OCs was investigated. Safe trajectories and screw lengths for OC screws and C0–C1 transarticular screws without hypoglossal canal or atlantooccipital joint compromise were estimated. RESULTS: The average screw length and safe sagittal and medial angulations for OC screws were 19.9±2.3 mm, ≤6.4°±2.4° cranially, and 31.1°±3° medially, respectively. An OC screw could not be accommodated by 27% of the population. The safe sagittal angles and screw lengths for C0–C1 transarticular screw insertion (48.9°±5.7° cranial, 26.7±2.9 mm for junctional entry technique; 36.7°±4.6° cranial, 31.6±2.7 mm for caudal C1 arch entry technique, respectively) were significantly different than those in other populations. The risk of vertebral artery injury was high for the caudal C1 arch entry technique. Screw placement was uncertain in 48% of Indians due to the presence of aberrant anatomy. CONCLUSIONS: There were significant differences in the metrics of OC-based OCF between Indian and other populations. Because of the smaller occipital squama dimensions in Indians, OC-based OCF techniques may have a higher application rate and could be a viable alternative/salvage option in selected cases. Preoperative CT, including three-dimensional-CT-angiography (to delineate vertebral artery course), is imperative to avoid complications resulting from aberrant bony and vascular anatomy. Our data can serve as a valuable reference guide in placing these screws safely under fluoroscopic guidance. Korean Society of Spine Surgery 2018-04 2018-04-13 /pmc/articles/PMC5913011/ /pubmed/29713401 http://dx.doi.org/10.4184/asj.2018.12.2.214 Text en Copyright © 2018 by Korean Society of Spine Surgery http://creativecommons.org/licenses/by-nc/4.0/ 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 Bosco, Aju Venugopal, Prakash Shetty, Ajoy Prasad Shanmuganathan, Rajasekaran Kanna, Rishi Mugesh Morphometric Evaluation of Occipital Condyles: Defining Optimal Trajectories and Safe Screw Lengths for Occipital Condyle-Based Occipitocervical Fixation in Indian Population |
title | Morphometric Evaluation of Occipital Condyles: Defining Optimal Trajectories and Safe Screw Lengths for Occipital Condyle-Based Occipitocervical Fixation in Indian Population |
title_full | Morphometric Evaluation of Occipital Condyles: Defining Optimal Trajectories and Safe Screw Lengths for Occipital Condyle-Based Occipitocervical Fixation in Indian Population |
title_fullStr | Morphometric Evaluation of Occipital Condyles: Defining Optimal Trajectories and Safe Screw Lengths for Occipital Condyle-Based Occipitocervical Fixation in Indian Population |
title_full_unstemmed | Morphometric Evaluation of Occipital Condyles: Defining Optimal Trajectories and Safe Screw Lengths for Occipital Condyle-Based Occipitocervical Fixation in Indian Population |
title_short | Morphometric Evaluation of Occipital Condyles: Defining Optimal Trajectories and Safe Screw Lengths for Occipital Condyle-Based Occipitocervical Fixation in Indian Population |
title_sort | morphometric evaluation of occipital condyles: defining optimal trajectories and safe screw lengths for occipital condyle-based occipitocervical fixation in indian population |
topic | Clinical Study |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5913011/ https://www.ncbi.nlm.nih.gov/pubmed/29713401 http://dx.doi.org/10.4184/asj.2018.12.2.214 |
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