Relationship between O-EA angle and lower cervical curvature in patients with anterior atlantoaxial dislocation before and after occipitocervical fusion_Chinese Journal of Reparative and Reconstructive Surgery

Authors：

CHEN Taiyong ^1,2 , YANG Xi ¹ , XIU Peng ¹ ,  SONG Yueming ¹

1. Department of Orthopedics, West China Hospital, Sichuan University, Chengdu Sichuan, 610041, P.R.China;
2. Department of Orthopedics, the Second Affiliated Hospital of Zunyi Medical University, Zunyi Guizhou, 563006, P.R.China;

Corresponding author：

SONG Yueming, Email: hx_sym@163.com

Keywords：

Occipitocervical fusion; O-EA angle; lower cervical curvature; anterior atlantoaxial dislocation

DOI：

10.7507/1002-1892.202011057

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Objective To investigate the relationship between O-EA angle and lower cervical curvature in patients with anterior atlantoaxial dislocation undergoing occipitocervical fusion, and to analyze the effect of O-EA angle on lower cervical curvature.Methods The clinical data of 61 patients with anterior atlantoaxial dislocation undergoing occipitocervical fusion who were admitted between April 2010 and July 2018 and met the selection criteria were retrospectively analyzed. There were 32 males and 29 females, with an age of 14-76 years (mean, 50.7 years). The fixed segment included 19 cases of C₀-C₂, 27 cases of C₀-C₃, 14 cases of C₀-C₄, and 1 case of C₀-C₅. The O-EA angle, C_2-7 Cobb angle, and T₁ tilt angle were measured before operation and at last follow-up. According to the O-EA angle measured at last follow-up, the patients were divided into <95° group (group A), 95°-105° group (group B), and >105° group (group C), and compared the differences of gender, age, fixed segment (short segment was at C₃ and above, long segment was beyond C₃), and C_2-7 Cobb angle. Correlation analysis between the O-EA angle and C_2-7 Cobb angle before operation and at last follow-up, as well as the changes of O-EA angle and C_2-7 Cobb angle between before operation and at last follow-up were analyzed.Results All 61 patients were followed up 12-24 months, with an average of 22.4 months. There was no significant difference in O-EA angle, C_2-7 Cobb angle, and T₁ tilt angle before operation and at last follow-up (P>0.05). According to the last follow-up O-EA angle grouping, there were 14 cases in group A, 29 cases in group B, and 18 cases in group C. There was no significant difference in age, gender composition, and fixed segment composition among the three groups (P>0.05); the differences in C_2-7 Cobb angles among the three groups were significant (P<0.05), groups A, B, and C showed a gradually increasing trend. The O-EA angle was positively correlated with C_2-7 Cobb angle before operation and at last follow-up (r=0.572, P=0.000; r=0.618, P=0.000); O-EA angle change at last follow-up was also positively correlated with C_2-7 Cobb change (r=0.446, P=0.000).Conclusion The O-EA angle of patients with anterior atlantoaxial dislocation is positively correlated with C_2-7 Cobb angle. Too large O-EA angle should be avoided during occipitocervical fixation, otherwise it may accelerate the degeneration of the lower cervical spine.

Citation： CHEN Taiyong, YANG Xi, XIU Peng, SONG Yueming. Relationship between O-EA angle and lower cervical curvature in patients with anterior atlantoaxial dislocation before and after occipitocervical fusion. Chinese Journal of Reparative and Reconstructive Surgery, 2021, 35(4): 453-457. doi: 10.7507/1002-1892.202011057 Copy

1.	Garrido BJ, Sasso RC. Occipitocervical fusion. Orthop Clin North Am, 2012, 43(1): 1-9.
2.	王鑫鑫, 王利民, 王卫东, 等. 枕颈融合角度与颅颈交界区畸形患者下颈椎退变的关系. 中国组织工程研究, 2014, 18(4): 613-618.
3.	孟阳, 刘浩, 戎鑫, 等. 颅底凹陷症合并寰枢椎脱位患者枕颈角与下颈椎曲度的关系. 中国脊柱脊髓杂志, 2017, 27(1): 25-30.
4.	Matsunaga S, Onishi T, Sakou T. Significance of occipitoaxial angle in subaxial lesion after occipitocervical fusion. Spine (Phila Pa 1976), 2001, 26(2): 161-165.
5.	王圣林, 王超, Kirkham B. Wood, 等. 寰枢关节不稳或脱位患者上颈椎曲度改变对下颈椎的影响. 中国脊柱脊髓杂志, 2009, 19(7): 502-505.
6.	Shoda N, Takeshita K, Seichi A, et al. Measurement of occipitocervical angle. Spine (Phila Pa 1976), 2004, 29(10): E204-208.
7.	Kunakornsawat S, Pluemvitayaporn T, Pruttikul P, et al. A new method for measurement of occipitocervical angle by occiput-C₃ angle. Eur J Orthop Surg Traumatol, 2017, 27(8): 1051-1056.
8.	Chen T, Yang X, Kong W, et al. Impact of the occiput and external acoustic meatus to axis angle on dysphagia in patients suffering from anterior atlantoaxial subluxation after occipitocervical fusion. Spine J, 2019, 19(8): 1362-1368.
9.	Morizane K, Takemoto M, Neo M, et al. Occipital and external acoustic meatus to axis angle as a predictor of the oropharyngeal space in healthy volunteers: a novel parameter for craniocervical junction alignment. Spine J, 2018, 18(5): 811-817.
10.	Passias PG, Wang S, Kozanek M, et al. Relationship between the alignment of the occipitoaxial and subaxial cervical spine in patients with congenital atlantoxial dislocations. J Spinal Disord Tech, 2013, 26(1): 15-21.
11.	Meng Y, Chen H, Lou J, et al. Posterior distraction reduction and occipitocervical fixation for the treatment of basilar invagination and atlantoaxial dislocation. Clin Neurol Neurosurg, 2016, 140: 60-67.
12.	Okada E, Matsumoto M, Ichihara D, et al. Does the sagittal alignment of the cervical spine have an impact on disk degeneration? Minimum 10-year follow-up of asymptomatic volunteers. Eur Spine J, 2009, 18(11): 1644-1651.
13.	Miyazaki M, Hymanson HJ, Morishita Y, et al. Kinematic analysis of the relationship between sagittal alignment and disc degeneration in the cervical spine. Spine (Phila Pa 1976), 2008, 33(23): E870-876.
14.	Inada T, Furuya T, Kamiya K, et al. Postoperative increase in occiput-C2 angle negatively impacts subaxial lordosis after occipito-upper cervical posterior fusion surgery. Asian Spine J, 2016, 10(4): 744-747.
15.	Ames CP, Blondel B, Scheer JK, et al. Cervical radiographical alignment: comprehensive assessment techniques and potential importance in cervical myelopathy. Spine (Phila Pa 1976), 2013, 38(22 Suppl 1): S149-160.
16.	Lin S, Zhou F, Sun Y, et al. The severity of operative invasion to the posterior muscular-ligament complex influences cervical sagittal balance after open-door laminoplasty. Eur Spine J, 2015, 24(1): 127-135.
17.	Hey HWD, Lau ET, Wong GC, et al. Cervical alignment variations in different postures and predictors of normal cervical kyphosis: A new understanding. Spine (Phila Pa 1976), 2017, 42(21): 1614-1621.
18.	Knott PT, Mardjetko SM, Techy F. The use of the T₁ sagittal angle in predicting overall sagittal balance of the spine. Spine J, 2010, 10(11): 994-998.
19.	Matsubayashi Y, Shimizu T, Chikuda H, et al. Correlations of cervical sagittal alignment before and after occipitocervical fusion. Global Spine J, 2016, 6(4): 362-369.
20.	Kim B, Yoon DH, Ha Y, et al. Relationship between T₁ slope and loss of lordosis after laminoplasty in patients with cervical ossification of the posterior longitudinal ligament. Spine J, 2016, 16(2): 219-225.
21.	Kim TH, Lee SY, Kim YC, et al. T₁ slope as a predictor of kyphotic alignment change after laminoplasty in patients with cervical myelopathy. Spine (Phila Pa 1976), 2013, 38(16): E992-997.
22.	Cho JH, Ha JK, Kim DG, et al. Does preoperative T₁ slope affect radiological and functional outcomes after cervical laminoplasty? Spine (Phila Pa 1976), 2014, 39(26): E1575-1581.
23.	Jun HS, Chang IB, Song JH, et al. Is it possible to evaluate the parameters of cervical sagittal alignment on cervical computed tomographic scans? Spine (Phila Pa 1976), 2014, 39(10): E630-636.
24.	Been E, Shefi S, Soudack M. Cervical lordosis: the effect of age and gender. Spine J, 2017, 17(6): 880-888.
25.	Iorio J, Lafage V, Lafage R, et al. The effect of aging on cervical parameters in a normative north american population. Global Spine J, 2018, 8(7): 709-715.
26.	Pan J, Huang D, Hao D, et al. Occipitocervical fusion: fix to C2 or C3? Clin Neurol Neurosurg, 2014, 127: 134-139.

1. Garrido BJ, Sasso RC. Occipitocervical fusion. Orthop Clin North Am, 2012, 43(1): 1-9.
2. 王鑫鑫, 王利民, 王卫东, 等. 枕颈融合角度与颅颈交界区畸形患者下颈椎退变的关系. 中国组织工程研究, 2014, 18(4): 613-618.
3. 孟阳, 刘浩, 戎鑫, 等. 颅底凹陷症合并寰枢椎脱位患者枕颈角与下颈椎曲度的关系. 中国脊柱脊髓杂志, 2017, 27(1): 25-30.
4. Matsunaga S, Onishi T, Sakou T. Significance of occipitoaxial angle in subaxial lesion after occipitocervical fusion. Spine (Phila Pa 1976), 2001, 26(2): 161-165.
5. 王圣林, 王超, Kirkham B. Wood, 等. 寰枢关节不稳或脱位患者上颈椎曲度改变对下颈椎的影响. 中国脊柱脊髓杂志, 2009, 19(7): 502-505.
6. Shoda N, Takeshita K, Seichi A, et al. Measurement of occipitocervical angle. Spine (Phila Pa 1976), 2004, 29(10): E204-208.
7. Kunakornsawat S, Pluemvitayaporn T, Pruttikul P, et al. A new method for measurement of occipitocervical angle by occiput-C₃ angle. Eur J Orthop Surg Traumatol, 2017, 27(8): 1051-1056.
8. Chen T, Yang X, Kong W, et al. Impact of the occiput and external acoustic meatus to axis angle on dysphagia in patients suffering from anterior atlantoaxial subluxation after occipitocervical fusion. Spine J, 2019, 19(8): 1362-1368.
9. Morizane K, Takemoto M, Neo M, et al. Occipital and external acoustic meatus to axis angle as a predictor of the oropharyngeal space in healthy volunteers: a novel parameter for craniocervical junction alignment. Spine J, 2018, 18(5): 811-817.
10. Passias PG, Wang S, Kozanek M, et al. Relationship between the alignment of the occipitoaxial and subaxial cervical spine in patients with congenital atlantoxial dislocations. J Spinal Disord Tech, 2013, 26(1): 15-21.
11. Meng Y, Chen H, Lou J, et al. Posterior distraction reduction and occipitocervical fixation for the treatment of basilar invagination and atlantoaxial dislocation. Clin Neurol Neurosurg, 2016, 140: 60-67.
12. Okada E, Matsumoto M, Ichihara D, et al. Does the sagittal alignment of the cervical spine have an impact on disk degeneration? Minimum 10-year follow-up of asymptomatic volunteers. Eur Spine J, 2009, 18(11): 1644-1651.
13. Miyazaki M, Hymanson HJ, Morishita Y, et al. Kinematic analysis of the relationship between sagittal alignment and disc degeneration in the cervical spine. Spine (Phila Pa 1976), 2008, 33(23): E870-876.
14. Inada T, Furuya T, Kamiya K, et al. Postoperative increase in occiput-C2 angle negatively impacts subaxial lordosis after occipito-upper cervical posterior fusion surgery. Asian Spine J, 2016, 10(4): 744-747.
15. Ames CP, Blondel B, Scheer JK, et al. Cervical radiographical alignment: comprehensive assessment techniques and potential importance in cervical myelopathy. Spine (Phila Pa 1976), 2013, 38(22 Suppl 1): S149-160.
16. Lin S, Zhou F, Sun Y, et al. The severity of operative invasion to the posterior muscular-ligament complex influences cervical sagittal balance after open-door laminoplasty. Eur Spine J, 2015, 24(1): 127-135.
17. Hey HWD, Lau ET, Wong GC, et al. Cervical alignment variations in different postures and predictors of normal cervical kyphosis: A new understanding. Spine (Phila Pa 1976), 2017, 42(21): 1614-1621.
18. Knott PT, Mardjetko SM, Techy F. The use of the T₁ sagittal angle in predicting overall sagittal balance of the spine. Spine J, 2010, 10(11): 994-998.
19. Matsubayashi Y, Shimizu T, Chikuda H, et al. Correlations of cervical sagittal alignment before and after occipitocervical fusion. Global Spine J, 2016, 6(4): 362-369.
20. Kim B, Yoon DH, Ha Y, et al. Relationship between T₁ slope and loss of lordosis after laminoplasty in patients with cervical ossification of the posterior longitudinal ligament. Spine J, 2016, 16(2): 219-225.
21. Kim TH, Lee SY, Kim YC, et al. T₁ slope as a predictor of kyphotic alignment change after laminoplasty in patients with cervical myelopathy. Spine (Phila Pa 1976), 2013, 38(16): E992-997.
22. Cho JH, Ha JK, Kim DG, et al. Does preoperative T₁ slope affect radiological and functional outcomes after cervical laminoplasty? Spine (Phila Pa 1976), 2014, 39(26): E1575-1581.
23. Jun HS, Chang IB, Song JH, et al. Is it possible to evaluate the parameters of cervical sagittal alignment on cervical computed tomographic scans? Spine (Phila Pa 1976), 2014, 39(10): E630-636.
24. Been E, Shefi S, Soudack M. Cervical lordosis: the effect of age and gender. Spine J, 2017, 17(6): 880-888.
25. Iorio J, Lafage V, Lafage R, et al. The effect of aging on cervical parameters in a normative north american population. Global Spine J, 2018, 8(7): 709-715.
26. Pan J, Huang D, Hao D, et al. Occipitocervical fusion: fix to C2 or C3? Clin Neurol Neurosurg, 2014, 127: 134-139.

Chinese Journal of Reparative and Reconstructive Surgery

Relationship between O-EA angle and lower cervical curvature in patients with anterior atlantoaxial dislocation before and after occipitocervical fusion

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