{"title":"Normative ranges of horizontal gaze parameters and their correlations with cervical sagittal parameters.","authors":"Hamza Karabag, Ahmet Celal Iplikcioglu","doi":"10.1016/j.otsr.2025.104305","DOIUrl":null,"url":null,"abstract":"<p><strong>Background: </strong>Maintaining a horizontal gaze is crucial for humans to interact with their surroundings and perform daily tasks. This gaze is evaluated using horizontal gaze parameters, including the chin-brow vertical angle (CBVA), McGregor slope (MGS), and slope of the line of sight (SLS). However, the normative ranges for SLS and CBVA, as well as their associations with cervical sagittal parameters, remain unclear. This study aimed to determine the normal ranges of horizontal gaze parameters based on their relationships with cervical sagittal parameters.</p><p><strong>Hypothesis: </strong>The normal ranges of horizontal gaze parameters can be established by analyzing their correlations with cervical sagittal parameters.</p><p><strong>Patients and methods: </strong>In 50 asymptomatic individuals, horizontal gaze parameters and cervical sagittal parameters were assessed using standing lateral cervical radiographs that included the skull. Pearson's correlation coefficient was used to analyze the relationships between these parameters. Additionally, predictive formulas were derived through linear regression analysis of significantly correlated parameters to define the normative ranges of horizontal gaze parameters.</p><p><strong>Results: </strong>Horizontal gaze parameters demonstrated significant correlations with the C2 slope (C2S) (T1 slope [T1S] minus cervical lordosis [CL]) and the C2-7 sagittal vertical axis (C2-7 SVA). They also showed significant but relatively weaker correlations with CL (p < 0.05). Based on the normal CL range (-8° to -29.5°), the estimated ranges for CBVA, MGS, and SLS were -10.8° to 7.83°, -6° to 14°, and -15.5° to 8°, respectively.</p><p><strong>Discussion: </strong>The significant correlations between horizontal gaze parameters and C2S as well as C2-7 SVA allow for the identification of kyphotic thresholds. Furthermore, kyphotic and lordotic thresholds can be determined based on their relationship with CL. However, larger studies are necessary to refine predictive formulas further.</p><p><strong>Level of evidence: </strong>III.</p>","PeriodicalId":54664,"journal":{"name":"Orthopaedics & Traumatology-Surgery & Research","volume":" ","pages":"104305"},"PeriodicalIF":2.3000,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Orthopaedics & Traumatology-Surgery & Research","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1016/j.otsr.2025.104305","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ORTHOPEDICS","Score":null,"Total":0}
引用次数: 0
Abstract
Background: Maintaining a horizontal gaze is crucial for humans to interact with their surroundings and perform daily tasks. This gaze is evaluated using horizontal gaze parameters, including the chin-brow vertical angle (CBVA), McGregor slope (MGS), and slope of the line of sight (SLS). However, the normative ranges for SLS and CBVA, as well as their associations with cervical sagittal parameters, remain unclear. This study aimed to determine the normal ranges of horizontal gaze parameters based on their relationships with cervical sagittal parameters.
Hypothesis: The normal ranges of horizontal gaze parameters can be established by analyzing their correlations with cervical sagittal parameters.
Patients and methods: In 50 asymptomatic individuals, horizontal gaze parameters and cervical sagittal parameters were assessed using standing lateral cervical radiographs that included the skull. Pearson's correlation coefficient was used to analyze the relationships between these parameters. Additionally, predictive formulas were derived through linear regression analysis of significantly correlated parameters to define the normative ranges of horizontal gaze parameters.
Results: Horizontal gaze parameters demonstrated significant correlations with the C2 slope (C2S) (T1 slope [T1S] minus cervical lordosis [CL]) and the C2-7 sagittal vertical axis (C2-7 SVA). They also showed significant but relatively weaker correlations with CL (p < 0.05). Based on the normal CL range (-8° to -29.5°), the estimated ranges for CBVA, MGS, and SLS were -10.8° to 7.83°, -6° to 14°, and -15.5° to 8°, respectively.
Discussion: The significant correlations between horizontal gaze parameters and C2S as well as C2-7 SVA allow for the identification of kyphotic thresholds. Furthermore, kyphotic and lordotic thresholds can be determined based on their relationship with CL. However, larger studies are necessary to refine predictive formulas further.
期刊介绍：
Orthopaedics & Traumatology: Surgery & Research (OTSR) publishes original scientific work in English related to all domains of orthopaedics. Original articles, Reviews, Technical notes and Concise follow-up of a former OTSR study are published in English in electronic form only and indexed in the main international databases.
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