枕骨
矢状面
医学
颈椎
人体躯干
尸体痉挛
解剖
口腔正畸科
前凸
倾斜(摄像机)
颈椎
射线照相术
外科
几何学
数学
作者
Avinash G. Patwardhan,Robert M. Havey,Saeed Khayatzadeh,Muturi Muriuki,Leonard I. Voronov,Gerard Carandang,Ngọc Tuấn Nguyễn,Alexander J. Ghanayem,Dale Schuit,Alpesh A. Patel,Zachary A. Smith,William Sears
出处
期刊:Spine
[Ovid Technologies (Wolters Kluwer)]
日期:2015-06-01
卷期号:40 (11): 783-792
被引量:57
标识
DOI:10.1097/brs.0000000000000877
摘要
In Brief Study Design. A biomechanical study using human spine specimens. Objective. To study postural compensations in lordosis angles that are necessary to maintain horizontal gaze in the presence of forward head posture and increasing T1 sagittal tilt. Summary of Background Data. Forward head posture relative to the shoulders, assessed radiographically using the horizontal offset distance between the C2 and C7 vertebral bodies (C2–C7 [sagittal vertical alignment] SVA), is a measure of global cervical imbalance. This may result from kyphotic alignment of cervical segments, muscle imbalance, as well as malalignment of thoracolumbar spine. Methods. Ten cadaveric cervical spines (occiput-T1) were tested. The T1 vertebra was anchored to a tilting and translating base. The occiput was free to move vertically but its angular orientation was constrained to ensure horizontal gaze regardless of sagittal imbalance. A 5-kg mass was attached to the occiput to mimic head weight. Forward head posture magnitude and T1 tilt were varied and motions of individual vertebrae were measured to calculate C2–C7 SVA and lordosis across C0–C2 and C2–C7. Results. Increasing C2–C7 SVA caused flexion of lower cervical (C2–C7) segments and hyperextension of suboccipital (C0–C1–C2) segments to maintain horizontal gaze. Increasing kyphotic T1 tilt primarily increased lordosis across the C2–C7 segments. Regression models were developed to predict the compensatory C0–C2 and C2–C7 angulation needed to maintain horizontal gaze given values of C2–C7 SVA and T1 tilt. Conclusion. This study established predictive relationships between radiographical measures of forward head posture, T1 tilt, and postural compensations in the cervical lordosis angles needed to maintain horizontal gaze. The laboratory model predicted that normalization of C2–C7 SVA will reduce suboccipital (C0–C2) hyperextension, whereas T1 tilt reduction will reduce the hyperextension in the C2–C7 segments. The predictive relationships may help in planning corrective strategy in patients experiencing neck pain, which may be attributed to sagittal malalignment. Level of Evidence: N/A We used a laboratory model to investigate postural consequences of cervical sagittal imbalance. Increasing C2–C7 sagittal vertical alignment caused flexion of lower cervical (C2–C7) segments and hyperextension of suboccipital (C0–C1–C2) segments to maintain horizontal gaze. Increasing kyphotic tilt of T1 primarily increased lordosis across the C2–C7 segments.
科研通智能强力驱动
Strongly Powered by AbleSci AI