The Change of Cervical Spine Alignment Along with BMI in Asymptomatic Population: A Preliminary Analysis

The Change of Cervical Spine Alignment Along with BMI in Asymptomatic Population: A Preliminary Analysis | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research article The Change of Cervical Spine Alignment Along with BMI in Asymptomatic Population: A Preliminary Analysis Zhenxuan Shao, Gaole Dai, Qingqian Zhao, Ben Wang, Rui Wen, Xiaolei Zhang, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-66913/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 12 You are reading this latest preprint version Abstract Study design: A cross-sectional study Objective: Describe the difference in the cervical sagittal alignment between various BMI people. Summary of Background Data: Cervical sagittal imbalance is implicated in the development of various spinal disorders, and obesity was recognized as a global epidemic. But there were few studies focusing on the correlation between cervical sagittal alignment and body mass index (BMI). Methods: This study enrolled 140 asymptomatic volunteers from July 2016 to July 2019. Demographic data included gender, age and BMI, and radiographic parameters included chin–brow vertical angle (CBVA), occipital slope (OS), orbital tilt (OrT), orbital index (OI), occiput-C2 lordosis (O-C2), cervical lordosis (CL), C2-C7 sagittal vertical axis (C2-C7SVA) , cranial tilting (CrT), cervical tilting (CeT), T1 slope (TS), neck tilt (NT), and thoracic inlet angle (TIA). The data were analyzed by ANOVA statistical analyses. Results: In terms of the occipitocervical parameters, we found that there was no significant difference (OS, P=0.970; OrT, P=0.970; OI, P=0.798); In terms of cervical parameters, we found significant correlations between BMI and parameters (C2-C7SVA, P=0.005; TZC2-C7, P=0.030; CrT, P= 0.050; CeT, P=0.013), which reflected that forward head posture increases as BMI rises; In terms of thoracic parameters, we also found significant correlations between BMI and parameters (NT, P=0.014; TIA, P=0.050), which reflected that thoracic inlet lifts as BMI rises. Conclusions: We found that there are the correlations between cervical sagittal alignment (C2-C7SVA, TZC2-C7, CL, CrT, and CeT) and BMI, and forward head posture increases and thoracic inlet lifts in the obese, which can provide clinical advice and remind surgeons of BMI effect in reconstructive surgery for better prognoses. Orthopedics Asymptomatic individuals Cervical sagittal balance BMI Radiology Figures Figure 1 Figure 2 Figure 3 Introduction Disruption of cervical sagittal alignment was implicated in the development of various spinal disorders[ 1 – 3 ]. And severe cervical sagittal imbalance declined the patient’s health-related quality of life [ 4 , 5 ] and even lead to disability through compressing the spinal cord [ 6 , 7 ]. Therefore, cervical sagittal imbalance ought to be attached attention, and factors affecting cervical sagittal balance must be defined and identified before the diagnosis and treatment. Hence, a number of studies have focused on the factors and the morphology of cervical spine [ 8 , 9 ], and some previous studies[ 10 – 12 ] demonstrated cervical sagittal alignment was related to age and gender in asymptomatic population. Meanwhile, obesity was recognized as a global epidemic. In 2015, 600 million adults and 100 million children were obese in 195 countries[ 13 ]. Therefore, obese people, who accounted for a large proportion, cannot be ignored. And our previous studies implied that BMI is relative to cervical sagittal alignment[ 14 ]. However, there were few studies focusing on the correlation between cervical sagittal alignment and body mass index (BMI), which is a parameter to define obesity. Does cervical sagittal alignment changes as BMI rises in asymptomatic population? Are the standard of diagnosis and treatment different in people with various BMI? To answer these questions, we hypothesized there is a relationship between BMI and cervical sagittal parameters. We grouped asymptomatic volunteers according to different BMI to investigate the correlation of cervical spine alignment changes as BMI rises. Materials And Methods Asymptomatic Population The institutional review board of the hospital approved this study, and all volunteers approved this study by written informed consent. To begin with, 160 asymptomatic volunteers were recruited from July 2016 to July 2019. During the study, 3 volunteers were excluded due to the history of bony diseases, spinal diseases or myelopathy, 10 volunteers were excluded due to the history of obvious neck or back pain and 2 volunteers dropped out. In addition, 2 radiographs were excluded due to the loss of corresponding demographic data and 3 radiographs were excluded due to the criteria of radiograph. There were totally 140 plain radiographs to explore the correlation between BMI and cervical sagittal alignment. As for criteria, the inclusion criteria included Cobb angle less than 10°[ 15 , 16 ] in the coronal position, a chin–brow vertical angle (CBVA) less than 10° [ 9 , 10 , 12 ] in the sagittal position. The exclusion criteria included the history of bony diseases, spinal diseases, or myelopathy, and the history of neck or back pain. In the study, volunteers stood in an erect comfortable position, with elbows fully flexed and fists resting on clavicles. Because fists-on-clavicles position was deemed as a more functional sagittal profile, yielding less negative shift[ 8 ]. Radiographs were stored at the Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University. The equipment and software used in this study included an AGFA computed radiography system (AGFA Gevaert NV, Mortsel, Belgium), a Siemens 500 mA imaging machine (Siemens Corp., Germany), and a picture archiving and communication system. Radiographic Parameters Demographic data included gender, age and body mass index (BMI), was recorded. Radiographic parameters were measured by two researchers in a same screen and a third researcher would participate when disagreements occurred between two researchers. Radiographic parameters included chin–brow vertical angle (CBVA), occipital slope (OS), orbital tilt (OrT), orbital index (OI), occiput-C2 lordosis (O-C2), cervical lordosis (CL), C2-C7 sagittal vertical axis (C2-C7SVA), cranial tilting (CrT), cervical tilting (CeT), T1 slope (TS), neck tilt (NT), and thoracic inlet angle (TIA). The definitions of all radiographic parameters were described in Table 1 and Fig. 1 . Table 1 Definition of the radiographic parameters OS Angle between a horizontal line and the McRae line OrT Angle formed by the plumbline and a line connecting the orbit centre and the centre of McRae’s line OI Angle formed by a line perpendicular to the McRae’s line and a line connecting the orbit centre and the centre of McRae’s line O-C2 Angle between the McRae line and the lower plate of C2 CL Angle between the lower plate of C2 and the lower plate of C7 C2-C7SVA The horizontal offset from the posterosuperior corner of C7 to the vertebral body of C2 TZC2-C7 The horizontal offset from the posterosuperior corner of C7 to the posterosuperior corner of C2 CrT Angle formed by the plumb line and the line connecting the centre of T1 upper end plate with the tip of the dens CeT Angle formed by the vertical line of upper end plate and the line connecting the centre of T1 upper end plate with the tip of the dens TS Angle between a horizontal line and the superior endplate of T1 NT Angle formed by the plumb line and a line connecting upper end of the sternum and the center of T1 upper end plate TIA Angle formed by a line perpendicular to the superior endplate of T1 and a line connecting the centre of the T1 upper endplate and the upper end of the sternum OS, Occipital slope; OrT, orbital tilt; OI, orbital index; O-C2, Occiput-C2 lordosis; CL, cervical lordosis; C2-C7SVA, C2-C7 sagittal vertical axis; CrT, cranial tilting; CeT, cervical tilting; TS, T1 slope; NT neck tilt; TIA, thoracic inlet angle; TK, thoracic kyphosis Statistical Analysis All statistical analyses were performed with a SPSS version 19.0 (SPSS Inc, Chicago, IL, USA) and GraphPad Prism software Version 5 (GraphPad Software, Inc, 220 San Diego, CA), and descriptive parameters were in form of mean ± standard deviation. Correlations between BMI and other parameters were analyzed by ANOVA statistical analyses. A probability ( P ) value < 0.05 was considered statistically significant. Results Demographic data and radiographic data in asymptomatic volunteers All 140 asymptomatic volunteers were recruited and imaged. From group A to group D, the mean age were 42.3 ± 10.6, 40.7 ± 13.2, 41.8 ± 12.5, and 44.7 ± 10.9 years; the mean CBVA were 1.9 ± 4.7, 2.4 ± 3.3, 2.2 ± 4.2, and 1.4 ± 2.4°; the mean MALD were 5.7 ± 2.9, 5.8 ± 2.2, 6.0 ± 2.9, and 5.5 ± 3.1 mm, which reflected that there was no significant difference between groups in this cohort. (Table 2 ) Table 2 Demographic data of volunteers in four groups Group A: Underweight N = 30 Group B: Normal weight N = 50 Group C: Overweight N = 30 Group D: Obese N = 30 Female 19 25 15 13 Male 11 25 15 17 Age (years) 42.3 ± 10.6 40.7 ± 12.4 41.8 ± 12.5 44.7 ± 10.9 CBVA (°) 1.9 ± 4.7 2.4 ± 3.3 2.2 ± 4.2 1.4 ± 2.4 CBVA, chin–brow vertical angle Anova Statistical Analyses Of Radiographic Data To explore the differences among four groups, we performed ANOVA statistical analyses. In terms of the occipitocervical parameters, we found that there was no significant difference (OS, P = 0.970; OrT, P = 0.970; OI, P = 0.798). (Table 3 & Fig. 2 ) Table 3 Average value of all parameters and the difference among four groups by P value Group A: Underweight N = 30 Group B: Normal weight N = 50 Group C: Overweight N = 30 Group D: Obese N = 30 P value OS (°) 14.1 ± 5.5 14.7 ± 5.7 14.3 ± 6.2 14.3 ± 5.2 0.970 OrT (°) 64.8 ± 4.6 64.4 ± 5.7 64.5 ± 6.8 64.1 ± 4.8 0.970 OI (°) 78.9 ± 4.5 78.8 ± 4.9 78.1 ± 3.1 78.1 ± 4.1 0.798 O-C2 (°) 19.0 ± 6.9 18.4 ± 7.8 18.2 ± 8.7 18.1 ± 7.5 0.970 CL (°) 10.1 ± 10.3 12.8 ± 6.4 13.3 ± 10.7 15.7 ± 7.5 0.100 C2-C7SVA (mm) 17.4 ± 6.0 17.8 ± 7.2 19.6 ± 8.1 23.2 ± 7.1 0.005* TZC2-C7 (mm) 13.5 ± 7.1 14.9 ± 8.1 17.3 ± 8.8 19.2 ± 8.4 0.030* CrT (°) 4.1 ± 4.2 5.0 ± 4.3 6.3 ± 4.4 6.9 ± 4.4 0.050* CeT (°) 14.0 ± 8.1 11.7 ± 5.9 9.6 ± 5.8 9.2 ± 5.2 0.013* TS (°) 17.0 ± 5.3 17.3 ± 5.3 17.4 ± 5.6 17.5 ± 5.3 0.986 NT (°) 50.4 ± 6.9 51.1 ± 7.0 54.1 ± 5.1 54.9 ± 6.8 0.014* TIA (°) 68.5 ± 7.7 68.5 ± 7.3 70.2 ± 7.6 72.8 ± 6.3 0.050* OS, Occipital slope; OrT, orbital tilt; OI, orbital index; O-C2, Occiput-C2 lordosis; CL, cervical lordosis; C2-C7SVA, C2-C7 sagittal vertical axis; CrT, cranial tilting; CeT, cervical tilting; TS, T1 slope; NT neck tilt; TIA, thoracic inlet angle; * P < 0.05 In terms of cervical parameters, we found significant correlations between BMI and parameters. From group A to group D, the mean C2-C7SVA were 17.4 ± 6.0, 17.8 ± 7.2, 19.6 ± 8.1, and 23.2 ± 7.1 ( P = 0.005); the mean TZC2-C7 were 13.5 ± 7.1, 14.9 ± 8.1, 17.3 ± 8.8, and 19.2 ± 8.4 ( P = 0.030); the mean CrT were4.1 ± 4.2, 5.0 ± 4.3, 6.3 ± 4.4, and 6.9 ± 4.4, ( P = 0.050); the mean CeT were 14.0 ± 8.1, 11.7 ± 5.9, 9.6 ± 5.8, and 9.2 ± 5.2, ( P = 0.013). (Table 3 & Fig. 2 ) In terms of thoracic parameters, we also found significant correlations between BMI and parameters. From group A to group D, the mean NT were 50.4 ± 6.9, 51.1 ± 7.0, 54.1 ± 5.1, and 54.9 ± 6.8 ( P = 0.014); the mean TIA were 68.5 ± 7.7, 68.5 ± 7.3, 70.2 ± 7.6, and 72.8 ± 6.3 ( P = 0.050). (Table 3 & Fig. 2 ) Comparisons Among Four Groups Of All Significantly Different Parameters After analysis, we derived clear connections between BMI and C2-C7SVA, TZC2-C7, CrT, CeT, CL, NT, TIA, and we performed further analyses among four groups of all significantly different parameters. Interestingly, compare group B (Normal weight) with group D (Obese), we found that there are significantly different, whereas there was no significant difference between the group B (Normal weight) with group C (Overweight) expect NT, which mean that only significant increase of BMI leads to cervical sagittal imbalance. (Table 4 ) Table 4 Average value of all significantly different parameters Statistic comparison among groups A/B A/C A/D B/C B/D C/D C2-C7SVA (mm) 0.799 0.237 0.001* 0.305 0.002* 0.072 TZC2-C7 (mm) 0.436 0.071 0.006* 0.218 0.026* 0.396 CrT (°) 0.364 0.052 0.015* 0.198 0.062* 0.599 CeT (°) 0.147 0.019 0.008* 0.125 0.059* 0.780 NT (°) 0.665 0.022* 0.014* 0.045* 0.020* 0.608 TIA (°) 0.988 0.393 0.021* 0.324 0.009* 0.155 C2-C7SVA, C2-C7 sagittal vertical axis; CrT, cranial tilting; CeT, cervical tilting; NT neck tilt; TIA, thoracic inlet angle; P < 0.05 and comparisons among four groups by P value In addition, there was no significant difference between the group B (Normal weight) with group A (Underweight), which mean the cervical sagittal alignment of underweight people is normal; even though we also found there are significantly different compare group A (Underweight) with group D (Obese), whose difference may come from the difference between group B and group D, not from group A and group B. (Table 4 ) Discussion Cervical sagittal imbalance is implicated in the development of various spinal disorders[ 1 , 2 ] and associated with patient’s health-related quality of life [ 4 , 5 ]. However, there were few studies focusing on the correlation between BMI and cervical sagittal alignment. After analysis, we derived clear connections between BMI and C2-C7SVA, TZC2-C7, CrT, CeT, CL, NT, TIA (Fig. 2 ), which indicated that surgeons should take BMI into consideration in reconstructive surgery of cervical sagittal alignment. Forward Head Posture Increases As Bmi Rises Several studies[ 1 , 9 , 11 , 17 ] testified that C2-C7SVA is a crucial parameter in cervical sagittal balance, which was related to clinical symptoms. In study, C2-C7SVA were positive correlated with BMI, which reflected forward head posture increases as BMI rises. In line with our result, Oe et al[ 9 ] implied the correlation between C2-C7SVA and BMI in the result of his study. TZC2-C7 is a good addition for C2-C7SVA[ 18 ], and we also found TZC2-C7 increases as BMI rises. CrT is an angle formed by the plumb line and the line connecting the center of T1 upper end plate with the tip of the dens, which is contacted to the flexion state of the cervical spine[ 19 ]. In study, we found CrT increases as BMI rises, which also reflected the status of forward head posture. Similar to CeT, CeT is also a common parameter to reflect cervical sagittal alignment, and CeT decreases as BMI rises[ 11 , 19 ]. Combining C2-C7SVA, TZC2-C7, CrT, and CeT, we assessed forward head posture increases as BMI rises. This phenomenon may be caused by two reasons. On the one hand, we guessed that the pathological fat infiltration in paraspinal muscle lead to forward head posture. Accumulating evidences demonstrated that BMI was positive associated with fatty infiltration of paraspinal muscle[ 20 – 22 ], and previous studies showed that pathological muscle influences the cervical sagittal alignment[ 23 ] and quality of life[ 24 ]. On the other hand, the anterior shift of the center of gravity may be an explanation of the compensatory increasement of forward head posture. Accumulating evidences reported that obese individuals have significantly greater trunk mass and BMI is positively correlated with increased abdominal fatness[ 25 , 26 ]. And increased abdominal fatness leads to anterior shift of the center of gravity. Previous articles showed that the anterior shift of the center of gravity is compensated with the posterior tilt in the pelvis and the thoracic region[ 27 , 28 ], which explains the anterior tilt in cervical region. In line with our observed phenomenon, Brink et al.[ 29 ] pointed out that overweight or obese students have more neck flexion than thinner students, when working on desktop computers in their school computer classroom. And the clinical studies certified that obese negatively effect on postural stability, not only in one leg standing but also moving from sit to stand[ 30 , 31 ]; Excessive forward head posture and increased abdominal fatness were regarded as the potential factor of postural instability[ 32 , 33 ]. Thoracic Inlet Lifts As Bmi Rises As the important element of cervicothoracic junction, thoracic inlet is a circle, made up by T1 vertebral body, first ribs and the upper part of sternum. As previous studies[ 34 – 36 ] described, parameters of thoracic inlet, such as TIA and NT, were significant correlative with cervical sagittal balance. TIA is formed by a line perpendicular to the superior endplate of T1 and a line connecting the center of the T1 upper end plate and the upper end of the sternum. Different from TS, there is no significant change of TIA in different positions[ 37 , 38 ], which is an advantage to guide surgery when patients lay, not stand, on the operating table. And TIA was found to markedly increase with age by previous studies[ 11 , 12 , 39 ], which was consistent with our result. As for BMI, we found there was a correlation between BMI and TIA. Like TIA, NT is also positively related to BMI, which reflect the phenomenon thoracic inlet lifts as BMI rises, and Oe et al.[ 9 ] study also implied that NT was correlative with BMI in the result. Combining the tender of TIA and NT, we assessed thoracic inlet lifts as BMI rises and the change came from sternum, not T1 vertebral body. We guessed that a rising position of manubrium related to the level of T1 leads to a larger TIA and NT. Shi et al. and Kent et al. certified that as BMI rises, the ribs became more perpendicular to the spine and rib cage depth increased, which lead to a rising position of manubrium related to the level of T1[ 40 , 41 ]. Combining our results with those of previous studies, we assessed that forward head posture increases and thoracic inlet lifts, as BMI rises, in asymptomatic population (Fig. 3 ). corresponding to our result, Fabris et al[ 25 ] showed that postural changes in morbidly obese patients, and Koller et al[ 42 ] showed that the risk for revision of adult scoliosis surgery was increased, as BMI rises. Of course, the role of BMI cannot be further exaggerated. Because we found that only significant increase of BMI, such as obese, leads to cervical sagittal imbalance, and the cervical sagittal alignment of underweight people is normal. This is the first preliminary analysis of the change of cervical spine alignment along with BMI in asymptomatic population. In clinic, we advise obese patients with neck pain to lose weight to maintain cervical sagittal balance and reduce neck pressure. In surgery, surgeons can properly evaluate cervical alignment of obese patients with cervical disorders, and map out more precise cervical realignment parameters in obese patient with cervical deformity in infusion operation. This study has several limitations in fact. First, the number of volunteers can be more to support our conclusions and a larger scale study is our next proposal. Second, our volunteers are all Asians, for which a multi-ethnic study is need in our future. Third, besides fists-on-clavicles position, lying position and sitting position are the next aim. Conclusion There are the correlations between cervical sagittal alignment (C2-C7SVA, TZC2-C7, CL, CrT, and CeT) and BMI, and forward head posture increases and thoracic inlet lifts in the obese, which provide clinical advice and remind surgeons of the primary influencers of reconstructive surgery for better prognoses. Abbreviations BMI: body mass index; CBVA: chin–brow vertical angle; OS: occipital slope; OrT: orbital tilt; OI: orbital index; O-C2: occiput-C2 lordosis; CL: cervical lordosis; C2-C7SVA: C2-C7 sagittal vertical axis; CrT: cranial tilting; CeT: cervical tilting; TS: T1 slope; NT: neck tilt; TIA: thoracic inlet angle. Declarations Acknowledgements Not applicable. Authors' contributions (I) Conception and design: Xiangyang Wang, Ai-Min Wu, and Xiaolei Zhang; (II) Administrative support: Zhenxuan Shao; (III) Provision of study materials or patients: Gaole Dai, Ben Wang; (IV) Collection and assembly of data: Qingqian Zhao, Jiajie Lu; (V) Data analysis and interpretation: Zhenxuan Shao, Rui Wen; (VI) Manuscript writing: All authors; (VII) Final approval of manuscript: All authors Funding This work is supported by Zhejiang Provincial Natural Science Foundation of China (LQ19H060004), Wenzhou Science and Technology Bureau Foundation (ZY2019014), National Natural Science Foundation of China (81871806). Availability of data and materials The datasets used and or analysed during the current study are available from the corresponding author on reasonable request. Ethics approval and consent to participate All patients signed the informed consent form, and the use of the specimens was approved by the Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University Ethics Committee. Consent for publication Not applicable. Competing interests The authors declare that they have no competing interests References Iyer S, Nemani VM, Nguyen J, Elysee J, Burapachaisri A, Ames CP, Kim HJ. Impact of Cervical Sagittal Alignment Parameters on Neck Disability. Spine (Phila Pa 1976). 2016;41:371–7. Zhang JT, Li JQ, Niu RJ, Liu Z, Tong T, Shen Y. Predictors of cervical lordosis loss after laminoplasty in patients with cervical spondylotic myelopathy. Eur Spine J. 2017;26:1205–10. Blizzard SR, Krishnamoorthy B, Shinseki M, Betsch M, Yoo J. The magnitude of angular and translational displacement of dens fractures is dependent on the sagittal alignment of the cervical spine rather than the force of injury. Spine J. 2017;17:1859–65. 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Geography of Lumbar Paravertebral Muscle Fatty Infiltration: The Influence of Demographics, Low Back Pain, and Disability. Spine (Phila Pa 1976). 2019;44:1294–302. Saeed K, Olivia AK, Dale S, Robert MH, Leonard IV, Alexander JG, Avinash GP. Cervical Spine Muscle-Tendon Unit Length Differences Between Neutral and Forward Head Postures: Biomechanical Study Using Human Cadaveric Specimens. Phys Ther. 2017;97:756–66. Imagama S, Matsuyama Y, Hasegawa Y, Sakai Y, Ito Z, Ishiguro N, Hamajima N. Back muscle strength and spinal mobility are predictors of quality of life in middle-aged and elderly males. Eur Spine J. 2011;20:954–61. Fabris de Souza SA, Faintuch J, Valezi AC, Sant'Anna AF, Gama-Rodrigues JJ, de. Batista Fonseca IC and de Melo RD. Postural changes in morbidly obese patients. Obes Surg 2005; 15: 1013–1016. Rodacki AL, Fowler NE, Provensi CL, Rodacki Cde L, Dezan VH. Body mass as a factor in stature change. Clin Biomech (Bristol Avon). 2005;20:799–805. Beckers L, Bekaert J. The role of lordosis. Acta Orthop Belg. 1991;57(Suppl 1):198–202. Barrey C, Jund J, Noseda O, Roussouly P. Sagittal balance of the pelvis-spine complex and lumbar degenerative diseases. A comparative study about 85 cases. Eur Spine J. 2007;16:1459–67. Brink Y, Louw Q, Grimmer K, Jordaan E. The spinal posture of computing adolescents in a real-life setting. BMC Musculoskelet Disord. 2014;15:212. King AC, Challis JH, Bartok C, Costigan FA, Newell KM. Obesity, mechanical and strength relationships to postural control in adolescence. Gait Posture. 2012;35:261–5. McGraw B, McClenaghan BA, Williams HG, Dickerson J, Ward DS. Gait and postural stability in obese and nonobese prepubertal boys. Arch Phys Med Rehabil. 2000;81:484–9. Hue O, Simoneau M, Marcotte J, Berrigan F, Doré J, Marceau P, Marceau S. Tremblay A and Teasdale N. Body weight is a strong predictor of postural stability. Gait Posture. 2007;26:32–8. Sung Min S. Influence of Obesity on Postural Stability in Young Adults. Osong Public Health Res Perspect. 2016;7:378–81. Sang-Hun L, Ki-Tack K, Eun-Min S, Kyung-Soo S, Yoon-Ho K, Eun-Seok S. The influence of thoracic inlet alignment on the craniocervical sagittal balance in asymptomatic adults. J Spinal Disord Tech. 2012;25:41–7. Weng C, Wang J, Tuchman A, Wang J, Fu C, Hsieh PC, Buser Z, Wang JC. Influence of T1 Slope on the Cervical Sagittal Balance in Degenerative Cervical Spine: An Analysis Using Kinematic MRI. Spine (Phila Pa 1976). 2016;41:185–90. Wang ZL, Xiao JL, Mou JH, Qin TZ, Liu P. Analysis of Cervical Sagittal Balance Parameters in MRIs of Patients with Disc-Degenerative Disease. Med Sci Monit. 2015;21:3083–8. Xing R, Zhou G, Chen Q, Liang Y, Dong J. MRI to measure cervical sagittal parameters: a comparison with plain radiographs. Arch Orthop Trauma Surg. 2017;137:451–5. Jun HS, Jang IB, Song JH, Kim TH, Park MS, Kim SW, Oh JK. Is It Possible to Evaluate the Parameters of Cervical Sagittal Alignment on Cervical CT scan? Spine (Phila Pa 1976) 2014. Yokoyama K, Kawanishi M, Yamada M, Tanaka H, Ito Y, Kawabata S, Kuroiwa T. Age-related variations in global spinal alignment and sagittal balance in asymptomatic Japanese adults. Neurol Res. 2017;39:414–8. Kent R, Lee SH, Darvish K, Wang S, Poster CS, Lange AW, Brede C, Lange D, Matsuoka F. Structural and material changes in the aging thorax and their role in crash protection for older occupants. Stapp Car Crash J. 2005;49:231–49. Shi X, Cao L, Reed MP, Rupp JD, Hoff CN, Hu J. A statistical human rib cage geometry model accounting for variations by age, sex, stature and body mass index. J Biomech. 2014;47:2277–85. Koller H, Pfanz C, Meier O, Hitzl W, Mayer M, Bullmann V, Schulte TL. Factors influencing radiographic and clinical outcomes in adult scoliosis surgery: a study of 448 European patients. Eur Spine J. 2016;25:532–48. Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Major revision 07 Jan, 2021 Review # 3 received at journal 06 Jan, 2021 Reviewer # 3 agreed at journal 13 Dec, 2020 Review # 2 received at journal 04 Dec, 2020 Review # 1 received at journal 04 Dec, 2020 Reviewer # 2 agreed at journal 03 Nov, 2020 Reviewer # 1 agreed at journal 01 Nov, 2020 Reviewers invited by journal 20 Sep, 2020 Editor assigned by journal 27 Aug, 2020 First submitted to journal 26 Aug, 2020 Submission checks completed at journal 26 Aug, 2020 Editor invited by journal 26 Aug, 2020 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-66913","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research article","associatedPublications":[],"authors":[{"id":2184051,"identity":"dc415e95-0892-4a37-9bcb-b162f2317fce","order_by":0,"name":"Zhenxuan Shao","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4klEQVRIiWNgGAWjYBACNv7+zw8+/LCxs29vPvggoaKGsBY+iQNmhjN70pINeI4lGzw4c4ywFjmGBANpDrZDjBskfMwkH7YwE+EwhgMJxgw8B5jNJdjSKhIb2Bj427sT8GthbjjwuMDiDp/l7OZjNxJ3yDBInDm7gYAtBxuMZ/A8Y2a4cyztRuIZNgYDiVxCWpIZpHnYDjM23MgxK0hsYyZGSxpEywagFgbitEicYQMHsmTPsWSJhDPHeAj6Rb6/hxkclfzszQc//qiokeNv78WvBQPwkKZ8FIyCUTAKRgFWAADBJ006UfL8gAAAAABJRU5ErkJggg==","orcid":"","institution":"the second affiliated hospital and yuying children hospital of wenzhou medical university","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Zhenxuan","middleName":"","lastName":"Shao","suffix":""},{"id":2184052,"identity":"dcf6f6f7-8263-4a05-9a78-9ce6265677fa","order_by":1,"name":"Gaole Dai","email":"","orcid":"","institution":"Wenzhou Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Gaole","middleName":"","lastName":"Dai","suffix":""},{"id":2184053,"identity":"e6e673b1-d480-4ff8-ac2c-ba2705f474be","order_by":2,"name":"Qingqian Zhao","email":"","orcid":"","institution":"Wenzhou Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Qingqian","middleName":"","lastName":"Zhao","suffix":""},{"id":2184054,"identity":"5edac5fd-ee23-4ddd-8a57-d19f33ffdfe2","order_by":3,"name":"Ben Wang","email":"","orcid":"","institution":"Wenzhou Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Ben","middleName":"","lastName":"Wang","suffix":""},{"id":2184055,"identity":"6fbcddf5-5c7a-4c17-b173-7d7d1a63c634","order_by":4,"name":"Rui Wen","email":"","orcid":"","institution":"Wenzhou Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Rui","middleName":"","lastName":"Wen","suffix":""},{"id":2184056,"identity":"20a4a9bf-6504-420b-9792-bb49c5ef950d","order_by":5,"name":"Xiaolei Zhang","email":"","orcid":"","institution":"Wenzhou Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Xiaolei","middleName":"","lastName":"Zhang","suffix":""},{"id":2184057,"identity":"0b2cc996-4393-40b0-81a9-f18165eb02e5","order_by":6,"name":"Ai-Min Wu","email":"","orcid":"","institution":"Wenzhou Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Ai-Min","middleName":"","lastName":"Wu","suffix":""},{"id":2184058,"identity":"4b4548eb-26c9-49a3-8e11-c1cc59bf2afb","order_by":7,"name":"xiang-yang Wang","email":"","orcid":"","institution":"the second affiliated hospital and yuying children hospital of wenzhou medical university","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"xiang-yang","middleName":"","lastName":"Wang","suffix":""}],"badges":[],"createdAt":"2020-08-27 11:29:56","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-66913/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-66913/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":2339360,"identity":"10c82ef3-b51a-4e17-b095-c37ee78ea2db","added_by":"auto","created_at":"2020-09-10 12:56:38","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":848538,"visible":true,"origin":"","legend":"The definitions of all radiographic parameters. OS, Occipital slope; OrT, orbital tilt; OI, orbital index; O-C2, Occiput-C2 lordosis; CL, cervical lordosis; C2-C7SVA, C2-C7 sagittal vertical axis; CrT, cranial tilting; CeT, cervical tilting; TS, T1 slope; NT neck tilt; TIA, thoracic inlet angle; * P\u003c0.05","description":"","filename":"OnlineFigure1.Thedefinitionsofallradiographicparameters.Png","url":"https://assets-eu.researchsquare.com/files/rs-66913/v1/OnlineFigure1.Thedefinitionsofallradiographicparameters.Png"},{"id":2339361,"identity":"69b43455-67c5-4b3c-85c9-65e2e53650a1","added_by":"auto","created_at":"2020-09-10 12:56:38","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":431517,"visible":true,"origin":"","legend":"The line charts of cervical sagittal parameters. There are significantly different compare group B (Normal weight) with group D (Obese), whereas there was no significant difference between the group B (Normal weight) with group C (Overweight) expect NT; and there was no significant difference between the group B (Normal weight) with group A (Underweight).","description":"","filename":"OnlineFigure2.Thelinechartofcervicalsagittalparameters.Png","url":"https://assets-eu.researchsquare.com/files/rs-66913/v1/OnlineFigure2.Thelinechartofcervicalsagittalparameters.Png"},{"id":2339362,"identity":"2f1659f1-3590-42b1-bf95-5d5638c27a01","added_by":"auto","created_at":"2020-09-10 12:56:39","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":328178,"visible":true,"origin":"","legend":"Forward head posture increases, and thoracic inlet lifts as BMI rises. The change of C2-C7 sagittal vertical axis (C2C7SVA), TZC2-C7, cranial tilting (CrT), and cervical tilting (CeT), which reflect the phenomenon forward head posture increases; the increase of thoracic inlet angle (TIA) and neck tilt (NT), which reflect the phenomenon thoracic inlet lifts as BMI rises.","description":"","filename":"OnlineFigure3.Forwardheadpostureincreases.Png","url":"https://assets-eu.researchsquare.com/files/rs-66913/v1/OnlineFigure3.Forwardheadpostureincreases.Png"},{"id":13590247,"identity":"3eda0c73-1409-4f84-8182-2577a1f2ed95","added_by":"auto","created_at":"2021-09-17 05:03:41","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1776497,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-66913/v1/7dd1e39e-47a7-4c3d-9875-9cd6c48667c4.pdf"}],"financialInterests":"","formattedTitle":"\u003cp\u003eThe Change of Cervical Spine Alignment Along with BMI in Asymptomatic Population: A Preliminary Analysis\u003c/p\u003e","fulltext":[{"header":"Introduction","content":" \u003cp\u003eDisruption of cervical sagittal alignment was implicated in the development of various spinal disorders[\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. And severe cervical sagittal imbalance declined the patient\u0026rsquo;s health-related quality of life [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] and even lead to disability through compressing the spinal cord [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Therefore, cervical sagittal imbalance ought to be attached attention, and factors affecting cervical sagittal balance must be defined and identified before the diagnosis and treatment.\u003c/p\u003e \u003cp\u003eHence, a number of studies have focused on the factors and the morphology of cervical spine [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], and some previous studies[\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] demonstrated cervical sagittal alignment was related to age and gender in asymptomatic population. Meanwhile, obesity was recognized as a global epidemic. In 2015, 600\u0026nbsp;million adults and 100\u0026nbsp;million children were obese in 195 countries[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Therefore, obese people, who accounted for a large proportion, cannot be ignored. And our previous studies implied that BMI is relative to cervical sagittal alignment[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. However, there were few studies focusing on the correlation between cervical sagittal alignment and body mass index (BMI), which is a parameter to define obesity.\u003c/p\u003e \u003cp\u003eDoes cervical sagittal alignment changes as BMI rises in asymptomatic population? Are the standard of diagnosis and treatment different in people with various BMI? To answer these questions, we hypothesized there is a relationship between BMI and cervical sagittal parameters. We grouped asymptomatic volunteers according to different BMI to investigate the correlation of cervical spine alignment changes as BMI rises.\u003c/p\u003e "},{"header":"Materials And Methods","content":" \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eAsymptomatic Population\u003c/h2\u003e \u003cp\u003eThe institutional review board of the hospital approved this study, and all volunteers approved this study by written informed consent. To begin with, 160 asymptomatic volunteers were recruited from July 2016 to July 2019. During the study, 3 volunteers were excluded due to the history of bony diseases, spinal diseases or myelopathy, 10 volunteers were excluded due to the history of obvious neck or back pain and 2 volunteers dropped out. In addition, 2 radiographs were excluded due to the loss of corresponding demographic data and 3 radiographs were excluded due to the criteria of radiograph. There were totally 140 plain radiographs to explore the correlation between BMI and cervical sagittal alignment.\u003c/p\u003e \u003cp\u003eAs for criteria, the inclusion criteria included Cobb angle less than 10\u0026deg;[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] in the coronal position, a chin\u0026ndash;brow vertical angle (CBVA) less than 10\u0026deg; [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] in the sagittal position. The exclusion criteria included the history of bony diseases, spinal diseases, or myelopathy, and the history of neck or back pain. In the study, volunteers stood in an erect comfortable position, with elbows fully flexed and fists resting on clavicles. Because fists-on-clavicles position was deemed as a more functional sagittal profile, yielding less negative shift[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Radiographs were stored at the Second Affiliated Hospital and Yuying Children\u0026rsquo;s Hospital of Wenzhou Medical University. The equipment and software used in this study included an AGFA computed radiography system (AGFA Gevaert NV, Mortsel, Belgium), a Siemens 500\u0026nbsp;mA imaging machine (Siemens Corp., Germany), and a picture archiving and communication system.\u003c/p\u003e \u003c/div\u003e \n\u003ch2\u003eRadiographic Parameters\u003c/h2\u003e\n \u003cp\u003eDemographic data included gender, age and body mass index (BMI), was recorded. Radiographic parameters were measured by two researchers in a same screen and a third researcher would participate when disagreements occurred between two researchers. Radiographic parameters included chin\u0026ndash;brow vertical angle (CBVA), occipital slope (OS), orbital tilt (OrT), orbital index (OI), occiput-C2 lordosis (O-C2), cervical lordosis (CL), C2-C7 sagittal vertical axis (C2-C7SVA), cranial tilting (CrT), cervical tilting (CeT), T1 slope (TS), neck tilt (NT), and thoracic inlet angle (TIA). The definitions of all radiographic parameters were described in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDefinition of the radiographic parameters\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOS\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAngle between a horizontal line and the McRae line\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOrT\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAngle formed by the plumbline and a line connecting the orbit centre and the centre of McRae\u0026rsquo;s line\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAngle formed by a line perpendicular to the McRae\u0026rsquo;s line and a line connecting the orbit centre and the centre of McRae\u0026rsquo;s line\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eO-C2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAngle between the McRae line and the lower plate of C2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAngle between the lower plate of C2 and the lower plate of C7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC2-C7SVA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eThe horizontal offset from the posterosuperior corner of C7 to the vertebral body of C2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTZC2-C7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eThe horizontal offset from the posterosuperior corner of C7 to the posterosuperior corner of C2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCrT\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAngle formed by the plumb line and the line connecting the centre of T1 upper end plate with the tip of the dens\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCeT\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAngle formed by the vertical line of upper end plate and\u003c/p\u003e \u003cp\u003ethe line connecting the centre of T1 upper end plate with the tip of the dens\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAngle between a horizontal line and the superior endplate of T1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNT\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAngle formed by the plumb line and a line connecting upper end of the sternum and the center of T1 upper end plate\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTIA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAngle formed by a line perpendicular to the superior endplate of T1 and a line connecting the centre of the T1 upper endplate and the upper end of the sternum\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eOS, Occipital slope; OrT, orbital tilt; OI, orbital index; O-C2, Occiput-C2 lordosis; CL, cervical lordosis; C2-C7SVA, C2-C7 sagittal vertical axis; CrT, cranial tilting; CeT, cervical tilting; TS, T1 slope; NT neck tilt; TIA, thoracic inlet angle; TK, thoracic kyphosis\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eAll statistical analyses were performed with a SPSS version 19.0 (SPSS Inc, Chicago, IL, USA) and GraphPad Prism software Version 5 (GraphPad Software, Inc, 220 San Diego, CA), and descriptive parameters were in form of mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation. Correlations between BMI and other parameters were analyzed by ANOVA statistical analyses. A probability (\u003cem\u003eP\u003c/em\u003e) value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e \u003c/div\u003e "},{"header":"Results","content":" \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eDemographic data and radiographic data in asymptomatic volunteers\u003c/h2\u003e \u003cp\u003eAll 140 asymptomatic volunteers were recruited and imaged. From group A to group D, the mean age were 42.3\u0026thinsp;\u0026plusmn;\u0026thinsp;10.6, 40.7\u0026thinsp;\u0026plusmn;\u0026thinsp;13.2, 41.8\u0026thinsp;\u0026plusmn;\u0026thinsp;12.5, and 44.7\u0026thinsp;\u0026plusmn;\u0026thinsp;10.9 years; the mean CBVA were 1.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.7, 2.4\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3, 2.2\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2, and 1.4\u0026thinsp;\u0026plusmn;\u0026thinsp;2.4\u0026deg;; the mean MALD were 5.7\u0026thinsp;\u0026plusmn;\u0026thinsp;2.9, 5.8\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2, 6.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.9, and 5.5\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1\u0026nbsp;mm, which reflected that there was no significant difference between groups in this cohort. (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDemographic data of volunteers in four groups\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGroup A: Underweight\u003c/p\u003e \u003cp\u003eN\u0026thinsp;=\u0026thinsp;30\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGroup B: Normal weight\u003c/p\u003e \u003cp\u003eN\u0026thinsp;=\u0026thinsp;50\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGroup C: Overweight\u003c/p\u003e \u003cp\u003eN\u0026thinsp;=\u0026thinsp;30\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003eGroup D: Obese\u003c/p\u003e \u003cp\u003eN\u0026thinsp;=\u0026thinsp;30\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e42.3\u0026thinsp;\u0026plusmn;\u0026thinsp;10.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e40.7\u0026thinsp;\u0026plusmn;\u0026thinsp;12.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e41.8\u0026thinsp;\u0026plusmn;\u0026thinsp;12.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e44.7\u0026thinsp;\u0026plusmn;\u0026thinsp;10.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCBVA (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.4\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.2\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e1.4\u0026thinsp;\u0026plusmn;\u0026thinsp;2.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003eCBVA, chin\u0026ndash;brow vertical angle\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \n\u003ch2\u003eAnova Statistical Analyses Of Radiographic Data\u003c/h2\u003e\n \u003cp\u003eTo explore the differences among four groups, we performed ANOVA statistical analyses. In terms of the occipitocervical parameters, we found that there was no significant difference (OS, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.970; OrT, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.970; OI, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.798). (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e \u0026amp; Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAverage value of all parameters and the difference among four groups by \u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGroup A: Underweight\u003c/p\u003e \u003cp\u003eN\u0026thinsp;=\u0026thinsp;30\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGroup B: Normal weight\u003c/p\u003e \u003cp\u003eN\u0026thinsp;=\u0026thinsp;50\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGroup C: Overweight\u003c/p\u003e \u003cp\u003eN\u0026thinsp;=\u0026thinsp;30\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGroup D:\u003c/p\u003e \u003cp\u003eObese\u003c/p\u003e \u003cp\u003eN\u0026thinsp;=\u0026thinsp;30\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOS (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14.1\u0026thinsp;\u0026plusmn;\u0026thinsp;5.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14.7\u0026thinsp;\u0026plusmn;\u0026thinsp;5.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14.3\u0026thinsp;\u0026plusmn;\u0026thinsp;6.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e14.3\u0026thinsp;\u0026plusmn;\u0026thinsp;5.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.970\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOrT (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e64.8\u0026thinsp;\u0026plusmn;\u0026thinsp;4.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e64.4\u0026thinsp;\u0026plusmn;\u0026thinsp;5.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e64.5\u0026thinsp;\u0026plusmn;\u0026thinsp;6.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e64.1\u0026thinsp;\u0026plusmn;\u0026thinsp;4.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.970\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOI (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e78.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e78.8\u0026thinsp;\u0026plusmn;\u0026thinsp;4.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e78.1\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e78.1\u0026thinsp;\u0026plusmn;\u0026thinsp;4.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.798\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eO-C2 (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e19.0\u0026thinsp;\u0026plusmn;\u0026thinsp;6.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18.4\u0026thinsp;\u0026plusmn;\u0026thinsp;7.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e18.2\u0026thinsp;\u0026plusmn;\u0026thinsp;8.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e18.1\u0026thinsp;\u0026plusmn;\u0026thinsp;7.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.970\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCL (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10.1\u0026thinsp;\u0026plusmn;\u0026thinsp;10.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12.8\u0026thinsp;\u0026plusmn;\u0026thinsp;6.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13.3\u0026thinsp;\u0026plusmn;\u0026thinsp;10.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e15.7\u0026thinsp;\u0026plusmn;\u0026thinsp;7.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.100\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC2-C7SVA (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e17.4\u0026thinsp;\u0026plusmn;\u0026thinsp;6.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e17.8\u0026thinsp;\u0026plusmn;\u0026thinsp;7.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19.6\u0026thinsp;\u0026plusmn;\u0026thinsp;8.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e23.2\u0026thinsp;\u0026plusmn;\u0026thinsp;7.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.005*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTZC2-C7 (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13.5\u0026thinsp;\u0026plusmn;\u0026thinsp;7.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14.9\u0026thinsp;\u0026plusmn;\u0026thinsp;8.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e17.3\u0026thinsp;\u0026plusmn;\u0026thinsp;8.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e19.2\u0026thinsp;\u0026plusmn;\u0026thinsp;8.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.030*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCrT (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.1\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.0\u0026thinsp;\u0026plusmn;\u0026thinsp;4.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.3\u0026thinsp;\u0026plusmn;\u0026thinsp;4.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.050*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCeT (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14.0\u0026thinsp;\u0026plusmn;\u0026thinsp;8.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11.7\u0026thinsp;\u0026plusmn;\u0026thinsp;5.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9.6\u0026thinsp;\u0026plusmn;\u0026thinsp;5.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e9.2\u0026thinsp;\u0026plusmn;\u0026thinsp;5.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.013*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTS (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e17.0\u0026thinsp;\u0026plusmn;\u0026thinsp;5.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e17.3\u0026thinsp;\u0026plusmn;\u0026thinsp;5.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e17.4\u0026thinsp;\u0026plusmn;\u0026thinsp;5.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e17.5\u0026thinsp;\u0026plusmn;\u0026thinsp;5.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.986\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNT (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50.4\u0026thinsp;\u0026plusmn;\u0026thinsp;6.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e51.1\u0026thinsp;\u0026plusmn;\u0026thinsp;7.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e54.1\u0026thinsp;\u0026plusmn;\u0026thinsp;5.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e54.9\u0026thinsp;\u0026plusmn;\u0026thinsp;6.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.014*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTIA (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e68.5\u0026thinsp;\u0026plusmn;\u0026thinsp;7.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e68.5\u0026thinsp;\u0026plusmn;\u0026thinsp;7.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e70.2\u0026thinsp;\u0026plusmn;\u0026thinsp;7.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e72.8\u0026thinsp;\u0026plusmn;\u0026thinsp;6.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.050*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"6\" nameend=\"c6\" namest=\"c1\"\u003e \u003cp\u003eOS, Occipital slope; OrT, orbital tilt; OI, orbital index; O-C2, Occiput-C2 lordosis; CL, cervical lordosis; C2-C7SVA, C2-C7 sagittal vertical axis; CrT, cranial tilting; CeT, cervical tilting; TS, T1 slope; NT neck tilt; TIA, thoracic inlet angle; * \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn terms of cervical parameters, we found significant correlations between BMI and parameters. From group A to group D, the mean C2-C7SVA were 17.4\u0026thinsp;\u0026plusmn;\u0026thinsp;6.0, 17.8\u0026thinsp;\u0026plusmn;\u0026thinsp;7.2, 19.6\u0026thinsp;\u0026plusmn;\u0026thinsp;8.1, and 23.2\u0026thinsp;\u0026plusmn;\u0026thinsp;7.1 (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.005); the mean TZC2-C7 were 13.5\u0026thinsp;\u0026plusmn;\u0026thinsp;7.1, 14.9\u0026thinsp;\u0026plusmn;\u0026thinsp;8.1, 17.3\u0026thinsp;\u0026plusmn;\u0026thinsp;8.8, and 19.2\u0026thinsp;\u0026plusmn;\u0026thinsp;8.4 (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.030); the mean CrT were4.1\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2, 5.0\u0026thinsp;\u0026plusmn;\u0026thinsp;4.3, 6.3\u0026thinsp;\u0026plusmn;\u0026thinsp;4.4, and 6.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.4, (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.050); the mean CeT were 14.0\u0026thinsp;\u0026plusmn;\u0026thinsp;8.1, 11.7\u0026thinsp;\u0026plusmn;\u0026thinsp;5.9, 9.6\u0026thinsp;\u0026plusmn;\u0026thinsp;5.8, and 9.2\u0026thinsp;\u0026plusmn;\u0026thinsp;5.2, (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.013). (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e \u0026amp; Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eIn terms of thoracic parameters, we also found significant correlations between BMI and parameters. From group A to group D, the mean NT were 50.4\u0026thinsp;\u0026plusmn;\u0026thinsp;6.9, 51.1\u0026thinsp;\u0026plusmn;\u0026thinsp;7.0, 54.1\u0026thinsp;\u0026plusmn;\u0026thinsp;5.1, and 54.9\u0026thinsp;\u0026plusmn;\u0026thinsp;6.8 (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.014); the mean TIA were 68.5\u0026thinsp;\u0026plusmn;\u0026thinsp;7.7, 68.5\u0026thinsp;\u0026plusmn;\u0026thinsp;7.3, 70.2\u0026thinsp;\u0026plusmn;\u0026thinsp;7.6, and 72.8\u0026thinsp;\u0026plusmn;\u0026thinsp;6.3 (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.050). (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e \u0026amp; Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e \n\u003ch2\u003eComparisons Among Four Groups Of All Significantly Different Parameters\u003c/h2\u003e\n \u003cp\u003eAfter analysis, we derived clear connections between BMI and C2-C7SVA, TZC2-C7, CrT, CeT, CL, NT, TIA, and we performed further analyses among four groups of all significantly different parameters.\u003c/p\u003e \u003cp\u003eInterestingly, compare group B (Normal weight) with group D (Obese), we found that there are significantly different, whereas there was no significant difference between the group B (Normal weight) with group C (Overweight) expect NT, which mean that only significant increase of BMI leads to cervical sagittal imbalance. (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAverage value of all significantly different parameters\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"6\" nameend=\"c7\" namest=\"c2\"\u003e \u003cp\u003eStatistic comparison among groups\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eA/B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eA/C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eA/D\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eB/C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eB/D\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eC/D\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC2-C7SVA (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.799\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.237\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.001*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.305\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.002*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.072\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTZC2-C7 (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.436\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.071\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.006*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.218\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.026*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.396\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCrT (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.364\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.052\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.015*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.198\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.062*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.599\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCeT (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.147\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.019\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.008*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.125\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.059*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.780\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNT (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.665\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.022*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.014*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.045*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.020*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.608\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTIA (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.988\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.393\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.021*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.324\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.009*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.155\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"7\" nameend=\"c7\" namest=\"c1\"\u003e \u003cp\u003eC2-C7SVA, C2-C7 sagittal vertical axis; CrT, cranial tilting; CeT, cervical tilting; NT neck tilt; TIA, thoracic inlet angle; \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"7\"\u003e\u003cb\u003eand comparisons among four groups by\u003c/b\u003e \u003cspan type=\"BoldItalic\" class=\"BoldItalic\" name=\"Emphasis\"\u003eP\u003c/span\u003e \u003cb\u003evalue\u003c/b\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eIn addition, there was no significant difference between the group B (Normal weight) with group A (Underweight), which mean the cervical sagittal alignment of underweight people is normal; even though we also found there are significantly different compare group A (Underweight) with group D (Obese), whose difference may come from the difference between group B and group D, not from group A and group B. (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e)\u003c/p\u003e "},{"header":"Discussion","content":" \u003cp\u003eCervical sagittal imbalance is implicated in the development of various spinal disorders[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] and associated with patient\u0026rsquo;s health-related quality of life [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. However, there were few studies focusing on the correlation between BMI and cervical sagittal alignment. After analysis, we derived clear connections between BMI and C2-C7SVA, TZC2-C7, CrT, CeT, CL, NT, TIA (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), which indicated that surgeons should take BMI into consideration in reconstructive surgery of cervical sagittal alignment.\u003c/p\u003e \n\u003ch2\u003eForward Head Posture Increases As Bmi Rises\u003c/h2\u003e\n \u003cp\u003eSeveral studies[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] testified that C2-C7SVA is a crucial parameter in cervical sagittal balance, which was related to clinical symptoms. In study, C2-C7SVA were positive correlated with BMI, which reflected forward head posture increases as BMI rises. In line with our result, Oe et al[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] implied the correlation between C2-C7SVA and BMI in the result of his study. TZC2-C7 is a good addition for C2-C7SVA[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e], and we also found TZC2-C7 increases as BMI rises.\u003c/p\u003e \u003cp\u003eCrT is an angle formed by the plumb line and the line connecting the center of T1 upper end plate with the tip of the dens, which is contacted to the flexion state of the cervical spine[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. In study, we found CrT increases as BMI rises, which also reflected the status of forward head posture. Similar to CeT, CeT is also a common parameter to reflect cervical sagittal alignment, and CeT decreases as BMI rises[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eCombining C2-C7SVA, TZC2-C7, CrT, and CeT, we assessed forward head posture increases as BMI rises. This phenomenon may be caused by two reasons. On the one hand, we guessed that the pathological fat infiltration in paraspinal muscle lead to forward head posture. Accumulating evidences demonstrated that BMI was positive associated with fatty infiltration of paraspinal muscle[\u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], and previous studies showed that pathological muscle influences the cervical sagittal alignment[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] and quality of life[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. On the other hand, the anterior shift of the center of gravity may be an explanation of the compensatory increasement of forward head posture. Accumulating evidences reported that obese individuals have significantly greater trunk mass and BMI is positively correlated with increased abdominal fatness[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. And increased abdominal fatness leads to anterior shift of the center of gravity. Previous articles showed that the anterior shift of the center of gravity is compensated with the posterior tilt in the pelvis and the thoracic region[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e], which explains the anterior tilt in cervical region.\u003c/p\u003e \u003cp\u003eIn line with our observed phenomenon, Brink et al.[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e] pointed out that overweight or obese students have more neck flexion than thinner students, when working on desktop computers in their school computer classroom. And the clinical studies certified that obese negatively effect on postural stability, not only in one leg standing but also moving from sit to stand[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]; Excessive forward head posture and increased abdominal fatness were regarded as the potential factor of postural instability[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e].\u003c/p\u003e \n\u003ch2\u003eThoracic Inlet Lifts As Bmi Rises\u003c/h2\u003e\n \u003cp\u003eAs the important element of cervicothoracic junction, thoracic inlet is a circle, made up by T1 vertebral body, first ribs and the upper part of sternum. As previous studies[\u003cspan additionalcitationids=\"CR35\" citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e] described, parameters of thoracic inlet, such as TIA and NT, were significant correlative with cervical sagittal balance.\u003c/p\u003e \u003cp\u003eTIA is formed by a line perpendicular to the superior endplate of T1 and a line connecting the center of the T1 upper end plate and the upper end of the sternum. Different from TS, there is no significant change of TIA in different positions[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e], which is an advantage to guide surgery when patients lay, not stand, on the operating table. And TIA was found to markedly increase with age by previous studies[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e], which was consistent with our result. As for BMI, we found there was a correlation between BMI and TIA. Like TIA, NT is also positively related to BMI, which reflect the phenomenon thoracic inlet lifts as BMI rises, and Oe et al.[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] study also implied that NT was correlative with BMI in the result.\u003c/p\u003e \u003cp\u003eCombining the tender of TIA and NT, we assessed thoracic inlet lifts as BMI rises and the change came from sternum, not T1 vertebral body. We guessed that a rising position of manubrium related to the level of T1 leads to a larger TIA and NT. Shi et al. and Kent et al. certified that as BMI rises, the ribs became more perpendicular to the spine and rib cage depth increased, which lead to a rising position of manubrium related to the level of T1[\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eCombining our results with those of previous studies, we assessed that forward head posture increases and thoracic inlet lifts, as BMI rises, in asymptomatic population (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). corresponding to our result, Fabris et al[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e] showed that postural changes in morbidly obese patients, and Koller et al[\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e] showed that the risk for revision of adult scoliosis surgery was increased, as BMI rises. Of course, the role of BMI cannot be further exaggerated. Because we found that only significant increase of BMI, such as obese, leads to cervical sagittal imbalance, and the cervical sagittal alignment of underweight people is normal.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThis is the first preliminary analysis of the change of cervical spine alignment along with BMI in asymptomatic population. In clinic, we advise obese patients with neck pain to lose weight to maintain cervical sagittal balance and reduce neck pressure. In surgery, surgeons can properly evaluate cervical alignment of obese patients with cervical disorders, and map out more precise cervical realignment parameters in obese patient with cervical deformity in infusion operation.\u003c/p\u003e \u003cp\u003eThis study has several limitations in fact. First, the number of volunteers can be more to support our conclusions and a larger scale study is our next proposal. Second, our volunteers are all Asians, for which a multi-ethnic study is need in our future. Third, besides fists-on-clavicles position, lying position and sitting position are the next aim.\u003c/p\u003e "},{"header":"Conclusion","content":" \u003cp\u003eThere are the correlations between cervical sagittal alignment (C2-C7SVA, TZC2-C7, CL, CrT, and CeT) and BMI, and forward head posture increases and thoracic inlet lifts in the obese, which provide clinical advice and remind surgeons of the primary influencers of reconstructive surgery for better prognoses.\u003c/p\u003e "},{"header":"Abbreviations","content":"\u003cp\u003eBMI: body mass index; CBVA: chin\u0026ndash;brow vertical angle; OS: occipital slope; OrT: orbital tilt; OI: orbital index; O-C2: occiput-C2 lordosis; CL: cervical lordosis; C2-C7SVA: C2-C7 sagittal vertical axis; CrT: cranial tilting; CeT: cervical tilting; TS: T1 slope; NT: neck tilt; TIA: thoracic inlet angle.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors' contributions \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e(I) Conception and design: Xiangyang Wang, Ai-Min Wu, and Xiaolei Zhang; (II) Administrative support: Zhenxuan Shao; (III) Provision of study materials or patients: Gaole Dai, Ben Wang; (IV) Collection and assembly of data: Qingqian Zhao, Jiajie Lu; (V) Data analysis and interpretation: Zhenxuan Shao, Rui Wen; (VI) Manuscript writing: All authors; (VII) Final approval of manuscript: All authors\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work is supported by Zhejiang Provincial Natural Science Foundation of China (LQ19H060004), Wenzhou Science and Technology Bureau Foundation (ZY2019014), National Natural Science Foundation of China (81871806).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll patients signed the informed consent form, and the use of the specimens was approved by the Second Affiliated Hospital and Yuying Children\u0026rsquo;s Hospital of Wenzhou Medical University Ethics Committee.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e \u003cspan\u003eIyer S, Nemani VM, Nguyen J, Elysee J, Burapachaisri A, Ames CP, Kim HJ. 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Neurosurg Focus. 2010;28:E14.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eYukawa Y, Kato F, Suda K, Yamagata M, Ueta T. Age-related changes in osseous anatomy, alignment, and range of motion of the cervical spine. Part I: Radiographic data from over 1,200 asymptomatic subjects. Eur Spine J. 2012;21:1492\u0026ndash;8.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eOe S, Togawa D, Nakai K, Yamada T, Arima H, Banno T, Yasuda T, Kobayasi S, Yamato Y, Hasegawa T, Yoshida G, Matsuyama Y. The Influence of Age and Sex on Cervical Spinal Alignment Among Volunteers Aged Over 50. Spine (Phila Pa 1976). 2015;40:1487\u0026ndash;94.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eMoon Soo P, Seong-Hwan M, Hwan-Mo L, Seok Woo K, Tae-Hwan K, Seung Yeop L, Riew KD. The effect of age on cervical sagittal alignment: normative data on 100 asymptomatic subjects. 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Spine (Phila Pa 1976). 2016;41:1837\u0026ndash;44.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eAshkan A, Mohammad HF, Marissa BR, Patrick S, Kara E, Alex L, Laurie M, Ali HM, Maziar M-L, Mohsen N, Joseph SS, Theo V, Kalkidan HA, Cristiana A, Muktar BA, Ziyad A-A, Ala\u0026rsquo;a A, Rajaa A-R, Azmeraw TA, Alemayehu A, Adeladza KA, Erfan A, Stephen MA, Ranjit MA, Johan \u0026Auml;, Hamid A, Amitava B, Aleksandra B, Estifanos B, Derrick AB, Addisu SB, Sibhatu B, Stan B, Espen B, Dube JB, Ismael C-N, Juan JC, Pedro C, Kelly C, Liliana GC, Leslie C, Solomon AD, Lalit D, Rakhi D, Samath DD, Bruce BD, Babak E, Alireza E, Valery LF, Jo\u0026atilde;o CF, Thomas F, Tsegaye TG, Audra G, Philimon NG, Atsushi G, Tesfa DH, Kokeb TH, Nima H-N, Simon IH, Masako H, Farhad I, Ritul K, Amir K, Srinivasa VK, Andre PK, Chandrasekharan NK, Yousef SK, Young-Ho K, Jagdish K, Daniel K, Yun JK, Yohannes K, Soewarta K, Tiffany K, Barthelemy Kuate D, Kumar GA, Heidi JL, Mall L, Xiaofeng L, Stephen SL, Patrick L, Alan DL, Rafael L, Azeem M, Reza M, Deborah CM, Mohsen M, Colm M, Stephen TM, Desalegn TM, George AM, Gert BMM, Haftay BM, Erkin MM, Ulrich OM, Jean JN, Carla MO, Felix AO, Mayowa OO, George CP, Farshad P, Mostafa Q, Anwar R, Rajesh KR, Chhabi LR, Nikolas R, Saeid S, Joshua AS, Juan RS, Itamar SS, Benn S, Monika S, Josef S, Aletta ES, Maria IS, Sadaf GS, Moretza S, Sara S, Min-Jeong S, Rahman S, Ivy S, Hirbo SR, Diego ASS, Jonathan IS, Jasvinder AS, Saverio S, Soumya S, Rafael T-S, Fentaw T, Bemnet AT, Balewgizie ST, Abdullah ST, Thakur JS, Marcello T, Roman T-M, Stefanos T, Kingsley NU, Olalekan AU, Masoud V, Tommi V, Vasiliy VV, Stein EV, Elisabete W, Andrea W, Joshua W, Ronny W, Yuichiro Y, Naohiro Y, Gerald Y, Zoubida Z. N Engl J Med. 2017;377:13\u0026ndash;27. Zerihun MZ, Ben Z and Christopher JLM. Health Effects of Overweight and Obesity in 195 Countries over 25 Years.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eShao ZX, Yan YZ, Pan XX, Chen SQ, Fang X, Chen XB, Wu AM, Wang XY. Factors Associated with Cervical Spine Alignment in an Asymptomatic Population: A Preliminary Analysis. World Neurosurg. 2019;122:e48\u0026ndash;58.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eSteven DG, Sigurd B, Keith B, William H, John RD. Correlation of radiographic parameters and clinical symptoms in adult scoliosis. Spine (Phila Pa 1976). 2005;30:682\u0026ndash;8.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eSuk KS, Kim KT, Lee SH, Kim JM. Significance of chin-brow vertical angle in correction of kyphotic deformity of ankylosing spondylitis patients. Spine (Phila Pa 1976). 2003;28:2001\u0026ndash;5.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eTang JA, Scheer JK, Smith JS, Deviren V, Bess S, Hart RA, Lafage V, Shaffrey CI, Schwab F, Ames CP. The impact of standing regional cervical sagittal alignment on outcomes in posterior cervical fusion surgery. Neurosurgery. 2015;76(Suppl 1):14\u0026ndash;21. discussion S21.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eHarrison DE, Harrison DD, Cailliet R, Troyanovich SJ, Janik TJ, Holland B. Cobb method or Harrison posterior tangent method: which to choose for lateral cervical radiographic analysis. Spine (Phila Pa 1976). 2000;25:2072\u0026ndash;8.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eLe Huec JC, Demezon H, Aunoble S. Sagittal parameters of global cervical balance using EOS imaging: normative values from a prospective cohort of asymptomatic volunteers. Eur Spine J. 2015;24:63\u0026ndash;71.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eFortin M, Videman T, Gibbons LE, Batti\u0026eacute; MC. Paraspinal muscle morphology and composition: a 15-yr longitudinal magnetic resonance imaging study. Med Sci Sports Exerc. 2014;46:893\u0026ndash;901.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eSebro R, O'Brien L, Torriani M, Bredella MA. Assessment of trunk muscle density using CT and its association with degenerative disc and facet joint disease of the lumbar spine. Skeletal Radiol. 2016;45:1221\u0026ndash;6.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eCrawford RJ, Volken T, Ni Mhuiris \u0026Aacute;, Bow CC, Elliott JM, Hoggarth MA, Samartzis D. Geography of Lumbar Paravertebral Muscle Fatty Infiltration: The Influence of Demographics, Low Back Pain, and Disability. Spine (Phila Pa 1976). 2019;44:1294\u0026ndash;302.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eSaeed K, Olivia AK, Dale S, Robert MH, Leonard IV, Alexander JG, Avinash GP. Cervical Spine Muscle-Tendon Unit Length Differences Between Neutral and Forward Head Postures: Biomechanical Study Using Human Cadaveric Specimens. Phys Ther. 2017;97:756\u0026ndash;66.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eImagama S, Matsuyama Y, Hasegawa Y, Sakai Y, Ito Z, Ishiguro N, Hamajima N. Back muscle strength and spinal mobility are predictors of quality of life in middle-aged and elderly males. Eur Spine J. 2011;20:954\u0026ndash;61.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eFabris de Souza SA, Faintuch J, Valezi AC, Sant'Anna AF, Gama-Rodrigues JJ, de. Batista Fonseca IC and de Melo RD. Postural changes in morbidly obese patients. Obes Surg 2005; 15: 1013\u0026ndash;1016.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eRodacki AL, Fowler NE, Provensi CL, Rodacki Cde L, Dezan VH. Body mass as a factor in stature change. Clin Biomech (Bristol Avon). 2005;20:799\u0026ndash;805.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eBeckers L, Bekaert J. The role of lordosis. Acta Orthop Belg. 1991;57(Suppl 1):198\u0026ndash;202.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eBarrey C, Jund J, Noseda O, Roussouly P. Sagittal balance of the pelvis-spine complex and lumbar degenerative diseases. A comparative study about 85 cases. Eur Spine J. 2007;16:1459\u0026ndash;67.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eBrink Y, Louw Q, Grimmer K, Jordaan E. The spinal posture of computing adolescents in a real-life setting. BMC Musculoskelet Disord. 2014;15:212.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eKing AC, Challis JH, Bartok C, Costigan FA, Newell KM. Obesity, mechanical and strength relationships to postural control in adolescence. Gait Posture. 2012;35:261\u0026ndash;5.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eMcGraw B, McClenaghan BA, Williams HG, Dickerson J, Ward DS. Gait and postural stability in obese and nonobese prepubertal boys. Arch Phys Med Rehabil. 2000;81:484\u0026ndash;9.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eHue O, Simoneau M, Marcotte J, Berrigan F, Dor\u0026eacute; J, Marceau P, Marceau S. Tremblay A and Teasdale N. Body weight is a strong predictor of postural stability. Gait Posture. 2007;26:32\u0026ndash;8.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eSung Min S. Influence of Obesity on Postural Stability in Young Adults. Osong Public Health Res Perspect. 2016;7:378\u0026ndash;81.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eSang-Hun L, Ki-Tack K, Eun-Min S, Kyung-Soo S, Yoon-Ho K, Eun-Seok S. The influence of thoracic inlet alignment on the craniocervical sagittal balance in asymptomatic adults. J Spinal Disord Tech. 2012;25:41\u0026ndash;7.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eWeng C, Wang J, Tuchman A, Wang J, Fu C, Hsieh PC, Buser Z, Wang JC. Influence of T1 Slope on the Cervical Sagittal Balance in Degenerative Cervical Spine: An Analysis Using Kinematic MRI. Spine (Phila Pa 1976). 2016;41:185\u0026ndash;90.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eWang ZL, Xiao JL, Mou JH, Qin TZ, Liu P. Analysis of Cervical Sagittal Balance Parameters in MRIs of Patients with Disc-Degenerative Disease. Med Sci Monit. 2015;21:3083\u0026ndash;8.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eXing R, Zhou G, Chen Q, Liang Y, Dong J. MRI to measure cervical sagittal parameters: a comparison with plain radiographs. Arch Orthop Trauma Surg. 2017;137:451\u0026ndash;5.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eJun HS, Jang IB, Song JH, Kim TH, Park MS, Kim SW, Oh JK. Is It Possible to Evaluate the Parameters of Cervical Sagittal Alignment on Cervical CT scan? Spine (Phila Pa 1976) 2014.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eYokoyama K, Kawanishi M, Yamada M, Tanaka H, Ito Y, Kawabata S, Kuroiwa T. Age-related variations in global spinal alignment and sagittal balance in asymptomatic Japanese adults. Neurol Res. 2017;39:414\u0026ndash;8.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eKent R, Lee SH, Darvish K, Wang S, Poster CS, Lange AW, Brede C, Lange D, Matsuoka F. Structural and material changes in the aging thorax and their role in crash protection for older occupants. Stapp Car Crash J. 2005;49:231\u0026ndash;49.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eShi X, Cao L, Reed MP, Rupp JD, Hoff CN, Hu J. A statistical human rib cage geometry model accounting for variations by age, sex, stature and body mass index. J Biomech. 2014;47:2277\u0026ndash;85.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eKoller H, Pfanz C, Meier O, Hitzl W, Mayer M, Bullmann V, Schulte TL. Factors influencing radiographic and clinical outcomes in adult scoliosis surgery: a study of 448 European patients. Eur Spine J. 2016;25:532\u0026ndash;48.\u003c/span\u003e \u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-musculoskeletal-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmsd","sideBox":"Learn more about [BMC Musculoskeletal Disorders](http://bmcmusculoskeletdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://author-welcome.nature.com/12891","title":"BMC Musculoskeletal Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Asymptomatic individuals, Cervical sagittal balance, BMI, Radiology ","lastPublishedDoi":"10.21203/rs.3.rs-66913/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-66913/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eStudy design: \u003c/strong\u003e\u003c/p\u003e\u003cp\u003eA cross-sectional study\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eObjective:\u003c/strong\u003e\u003c/p\u003e\u003cp\u003eDescribe the difference in the cervical sagittal alignment between various BMI people.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eSummary of Background Data:\u003c/strong\u003e\u003c/p\u003e\u003cp\u003eCervical sagittal imbalance is implicated in the development of various spinal disorders, and obesity was recognized as a global epidemic. But there were few studies focusing on the correlation between cervical sagittal alignment and body mass index (BMI).\u0026nbsp;\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003e\u003c/p\u003e\u003cp\u003eThis study enrolled 140 asymptomatic volunteers from July 2016 to July 2019. Demographic data included gender, age and BMI, and radiographic parameters included chin–brow vertical angle (CBVA), occipital slope (OS), orbital tilt (OrT), orbital index (OI), occiput-C2 lordosis (O-C2), cervical lordosis (CL), C2-C7 sagittal vertical axis (C2-C7SVA) , cranial tilting (CrT), cervical tilting (CeT), T1 slope (TS), neck tilt (NT), and thoracic inlet angle (TIA). The data were analyzed by ANOVA statistical analyses.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eResults: \u003c/strong\u003e\u003c/p\u003e\u003cp\u003eIn terms of the occipitocervical parameters, we found that there was no significant difference (OS, P=0.970; OrT, P=0.970; OI, P=0.798); In terms of cervical parameters, we found significant correlations between BMI and parameters (C2-C7SVA, P=0.005; TZC2-C7, P=0.030; CrT, P= 0.050; CeT, P=0.013), which reflected that forward head posture increases as BMI rises; In terms of thoracic parameters, we also found significant correlations between BMI and parameters (NT, P=0.014; TIA, P=0.050), which reflected that thoracic inlet lifts as BMI rises.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConclusions: \u003c/strong\u003e\u003c/p\u003e\u003cp\u003eWe found that there are the correlations between cervical sagittal alignment (C2-C7SVA, TZC2-C7, CL, CrT, and CeT) and BMI, and forward head posture increases and thoracic inlet lifts in the obese, which can provide clinical advice and remind surgeons of BMI effect in reconstructive surgery for better prognoses.\u003c/p\u003e","manuscriptTitle":"The Change of Cervical Spine Alignment Along with BMI in Asymptomatic Population: A Preliminary Analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2020-09-10 12:56:37","doi":"10.21203/rs.3.rs-66913/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2021-01-08T00:00:00+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2021-01-07T00:00:00+00:00","index":3,"fulltext":"Recommendation: Major revisions required\nForm responses:\n---\n\nComments to Author:\n---\nThe present study enrolled 140 healthy volunteer to analyze the relationship between their cervical spine alignments and BMI. No significant finding was noted between OC alignment and BMI but some significant correlations between BMI and cervical parameters. C2-7 SVA is significantly correlated with BMI but cervical lordosis and T1 slope are not. They suggested an increased forward head posture as BMI rises. There are comments from the reviewer.\n\n- The BMI data is never shown in this cohort. It is not clear how they divided the entire cohort into four groups, either. This should be clarify in the Methods section. What are the BMI data in the entire cohort and each group, respectively?\n- What is the gender distribution in their groups? Are they similar? What is the age distribution in this cohort? Is age a confounding factor to cervical parameters here? More detailed demographic data should be presented in this cohort.\n- What is MALD?\n- The method of measuring TZC2-C7 is not clear. And I also suggest they refine their figure 1. Some of the parameters are not illustrated and some of them are not clearly demonstrated. There is no illustrated case either. A couple of illustrated case may help the readers to better understand the idea of the study.\n- Is there any linear correlation between the cervical parameters and BMI? Instead of ANOVA study and comparison in-between groups, the best way to present the relationship in this study is a linear correlation between BMI and the cervical parameters found significant in this cohort. I would like to see some figures demonstrating the linear correlation between BMI and the cervical parameters.\n- As we know cervical lordosis and T1 slope are correlated with C2-7 SVA. In the present study, as C2-7 SVA is significantly different in each BMI group but cervical lordosis and T1 slope are not. How did they explain their results?\n* Publons Reviewer Recognition. Springer Nature can send verification of this review directly to Publons (a subsidiary of Clarivate Analytics). If you would like to take advantage of this service, please click on the “Yes” option below. Your name, email address, title of the reviewed manuscript, name of the journal, and date of your review submission (the “Review Data”) will then be transmitted to Publons upon publication of the manuscript. If you have already registered at Publons, they will notify you of the receipt of this review and update your profile as per your settings and their policy. If you are not registered with Publons, you will receive an email from them asking you to register in order for them to be able to recognize your review on your new profile page. Publons may use the Review Data to generate derivative metadata for the benefit of Publons and you as a reviewer, carefully considering the sensitivity of such information. For example, Publons may verify your record as a reviewer by updating your profile published on its webservice if you have registered for such service or help editors to identify candidate reviewers. Please find the details of processing in Publons’ privacy policy https://publons.com/about/terms: **No**\n* Declaration of competing interests: **'I declare that I have no competing interests**\n* Reviewer Publication Consent. I agree for my report to be made available under an Open Access Creative Commons CC-BY License (http://creativecommons.org/licenses/by/4.0) if this manuscript is accepted for publication. Any comments that I do not wish to be included in the published report have been included as confidential comments to the editor, which will not be published.: **I agree to the terms of the CC-BY 4.0 license; please do not publish my name with my report. (default)**\n* Is the study design appropriate to answer the research question (including the use of appropriate controls), and are the conclusions supported by the evidence presented?: **Yes**\n* Are the methods sufficiently described to allow the study to be repeated?: **Yes**\n* Is the use of statistics and treatment of uncertainties appropriate?: **No**\n* Is the presentation of the work clear?: **Yes**\n* Are the images in this manuscript (including electrophoretic gels and blots) free from apparent manipulation?: **Yes**\n"},{"type":"reviewerAgreed","content":"","date":"2020-12-14T01:00:00+00:00","index":3,"fulltext":""},{"type":"editorInvitedReview","content":"","date":"2020-12-05T00:00:00+00:00","index":2,"fulltext":"Recommendation: Reject\nForm responses:\n---\n\nComments to Author:\n---\nThis is a study that aimed to investigate the association between cervical sagittal alignment and BMI by analyzing radiographic parameters among four different BMI groups. However, I have some concerns with the study design, which the results cannot support your conclusion. More sufficient evidences are needed to conclude if there's correlation between each cervical sagittal alignment and BMI. I'm afraid that I cannot recommend this paper for publication.\n\n1. The assessment of cervical alignment is highly associated with the posture of head and neck, especially for C2-7 SVA, which the measurement can vary widely even for just a slight forward or backward movement of the head. It's difficult to assume that every volunteer is in the same posture by simply use one radiograph of fist-on-clavicle position for the analyses. The head posture can be different for each volunteer in his/her erect comfortable position. So, the finding of high BMI reflected the forward head posture remains questionable.\n2. Also, the authors stated that thoracic inlet angle (TIA) and neck tilt (NT) increases as BMI rise; however, people with high BMI among the overweight and obese groups tend to have thick thoracic trunk, so it's reasonable that these two parameters are higher than the normal BMI.\n3. T1 slope (TS) seems not to be associated with BMI. The value of TS is almost the same in each group, so maybe this is not an important parameter to investigate since it's similar in asymptomatic population. \n4. In methods, please give more a detailed explanation on how you divided into groups, such as the measurement of BMI, the number of cases in each group and the name of groups and etc. In addition, are the researchers blinded when they measured the radiographic parameters?\n5. English improvement is strongly suggested for your manuscript. There are grammatical errors, typos and punctuation mistakes throughout the manuscript should be corrected, for example, a space is missing before brackets for some in-text citations.* Publons Reviewer Recognition. Springer Nature can send verification of this review directly to Publons (a subsidiary of Clarivate Analytics). If you would like to take advantage of this service, please click on the “Yes” option below. Your name, email address, title of the reviewed manuscript, name of the journal, and date of your review submission (the “Review Data”) will then be transmitted to Publons upon publication of the manuscript. If you have already registered at Publons, they will notify you of the receipt of this review and update your profile as per your settings and their policy. If you are not registered with Publons, you will receive an email from them asking you to register in order for them to be able to recognize your review on your new profile page. Publons may use the Review Data to generate derivative metadata for the benefit of Publons and you as a reviewer, carefully considering the sensitivity of such information. For example, Publons may verify your record as a reviewer by updating your profile published on its webservice if you have registered for such service or help editors to identify candidate reviewers. Please find the details of processing in Publons’ privacy policy https://publons.com/about/terms: **No**\n* Declaration of competing interests: **I declare that I have no competing interests.**\n* Reviewer Publication Consent. I agree for my report to be made available under an Open Access Creative Commons CC-BY License (http://creativecommons.org/licenses/by/4.0) if this manuscript is accepted for publication. Any comments that I do not wish to be included in the published report have been included as confidential comments to the editor, which will not be published.: **I agree to the terms of the CC-BY 4.0 license; please do not publish my name with my report. (default)**\n* Is the study design appropriate to answer the research question (including the use of appropriate controls), and are the conclusions supported by the evidence presented?: **No**\n* Are the methods sufficiently described to allow the study to be repeated?: **Yes**\n* Is the use of statistics and treatment of uncertainties appropriate?: **Yes**\n* Is the presentation of the work clear?: **Yes**\n* Are the images in this manuscript (including electrophoretic gels and blots) free from apparent manipulation?: **Yes**\n"},{"type":"editorInvitedReview","content":"","date":"2020-12-05T00:00:00+00:00","index":1,"fulltext":"Recommendation: Accept after discretionary revisions\nForm responses:\n---\n\nComments to Author:\n---\nYour study concludes that obesity and cervical sagittal alignament are related to the prognosis of reconstructive surgery. This is just a hypothesis. Have you observed any actual practical efefct on the reconstructive surgeries in these patients.\nCan u please share your data in obese patients who underwent surgery.\n\nI found a lot of grammar errors as well eroors in syntax. please review the article for potential grammar corrections.\n\nline 207 from page 5-\n\" In line with our observed phenomenon, Brink et al.[29] \"- please rephrase the paragragh, as this is not grammatically correct.\n\n* Publons Reviewer Recognition. Springer Nature can send verification of this review directly to Publons (a subsidiary of Clarivate Analytics). If you would like to take advantage of this service, please click on the “Yes” option below. Your name, email address, title of the reviewed manuscript, name of the journal, and date of your review submission (the “Review Data”) will then be transmitted to Publons upon publication of the manuscript. If you have already registered at Publons, they will notify you of the receipt of this review and update your profile as per your settings and their policy. If you are not registered with Publons, you will receive an email from them asking you to register in order for them to be able to recognize your review on your new profile page. Publons may use the Review Data to generate derivative metadata for the benefit of Publons and you as a reviewer, carefully considering the sensitivity of such information. For example, Publons may verify your record as a reviewer by updating your profile published on its webservice if you have registered for such service or help editors to identify candidate reviewers. Please find the details of processing in Publons’ privacy policy https://publons.com/about/terms: **Yes**\n* Declaration of competing interests: **I declare that I have no competing interests**\n* Reviewer Publication Consent. I agree for my report to be made available under an Open Access Creative Commons CC-BY License (http://creativecommons.org/licenses/by/4.0) if this manuscript is accepted for publication. Any comments that I do not wish to be included in the published report have been included as confidential comments to the editor, which will not be published.: **I agree to the terms of the CC-BY 4.0 license; please do not publish my name with my report. 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