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Tan LA, Riew KD, Traynelis VC. Cervical Spine Deformity-Part 2: Management Algorithm and Anterior Techniques. Neurosurgery 2018; 81:561-567. [PMID: 28934448 DOI: 10.1093/neuros/nyx388] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 06/23/2017] [Indexed: 11/14/2022] Open
Abstract
A sound operative plan based on solid understanding of the pathology and biomechanics is the most important part of cervical deformity correction. Many different surgical options exist for operative management of cervical spine deformities. However, selecting the correct approach that ensures the optimal clinical outcome can be challenging and often controversial. In Part 2 of this three-part review series, we discuss the pre-operative planning, management algorithm, and anterior surgical techniques for cervical deformity correction.
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Tan LA, Riew KD, Traynelis VC. Cervical Spine Deformity-Part 1: Biomechanics, Radiographic Parameters, and Classification. Neurosurgery 2018; 81:197-203. [PMID: 28838143 DOI: 10.1093/neuros/nyx249] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 04/14/2017] [Indexed: 11/13/2022] Open
Abstract
Cervical spine deformities can have a significant negative impact on the quality of life by causing pain, myelopathy, radiculopathy, sensorimotor deficits, as well as inability to maintain horizontal gaze in severe cases. Many different surgical options exist for operative management of cervical spine deformities. However, selecting the correct approach that ensures the optimal clinical outcome can be challenging and is often controversial. We aim to provide an overview of cervical spine deformity in a 3-part series covering topics including the biomechanics, radiographic parameters, classification, treatment algorithms, surgical techniques, clinical outcome, and complication avoidance with a review of pertinent literature.
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Jeon SI, Hyun SJ, Han S, Lee BH, Kim KJ, Jahng TA, Kim HJ. Relationship Between Cervical Sagittal Alignment and Patient Outcomes After Anterior Cervical Fusion Surgery Involving 3 or More Levels. World Neurosurg 2018; 113:e548-e554. [PMID: 29476994 DOI: 10.1016/j.wneu.2018.02.088] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 02/11/2018] [Accepted: 02/13/2018] [Indexed: 10/18/2022]
Abstract
BACKGROUND T1 slope minus C2-7 lordosis (TS-CL) and cervical sagittal alignment reportedly affect health-related quality of life (HRQOL) scores after multilevel posterior cervical fusion surgery. There are no reports of a relationship between cervical alignment and patient outcomes after anterior cervical discectomy and fusion (ACDF) involving 3 or more levels. This study aimed to investigate the relationship between cervical sagittal alignment and patient-reported HRQOL after ACDF involving 3 or more levels. METHODS Thirty-three patients underwent ACDF involving 3 or more levels for cervical stenosis, cervical degenerative disorder, or ossification of the posterior longitudinal ligament (February 2006-April 2015). Mean follow-up duration was 57.6 ± 33.2 months. Radiographic measurements included C0-2 lordosis, C2-7 lordosis, C2-7 sagittal vertical axis (SVA), T1 slope, and T1 slope minus cervical lordosis (TS-CL). Clinical outcomes were evaluated by Neck Disability Index (NDI) and visual analog scale (VAS) scores. RESULTS There were significant correlations between C2-7 lordosis and T1 slope (r = 0.581, P = 0.004), and between C2-7 lordosis and TS-CL (r = -0.579, P = 0.004). C2-7 lordosis, C2-7 SVA, and TS-CL had no significant correlations with NDI or VAS score after surgery. C2-7 SVA was not significantly different before and after surgery. Postoperative TS-CL (P = 0.01) and changes in T1 slope (P = 0.028) and TS-CL (P = 0.01) were significantly correlated with changes in NDI. CONCLUSIONS ACDF surgery involving 3 or more levels under neutral supine position did not significantly change the postoperative cervical alignment, and thus may not significantly affect cervical alignment or HRQOL.
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Xing R, Liu W, Li X, Jiang L, Yishakea M, Dong J. Characteristics of cervical sagittal parameters in healthy cervical spine adults and patients with cervical disc degeneration. BMC Musculoskelet Disord 2018; 19:37. [PMID: 29390994 PMCID: PMC5795794 DOI: 10.1186/s12891-018-1951-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 01/21/2018] [Indexed: 11/10/2022] Open
Abstract
Background The cervical sagittal parameters of the normal population and the impact of disc degeneration on cervical sagittal alignment have not been clearly defined yet. This study is applied to investigate the characteristics and relationships of cervical sagittal parameters in normal adults and patients with cervical disc degeneration. Methods We reviewed 50 normal control subjects (normal group, NG) and 50 patients with cervical disc degeneration (degeneration group, DG), who had both cervical MRI and radiographs obtained together, between January 2010 and September 2015. Data including C2–7 lordosis (CL), T1 slope (T1S), thoracic inlet angle (TIA), neck tilt (NT), C2–7 sagittal vertical axis (C2–7 SVA), cervical tilting, and cranial tilting on cervical radiographs were collected and analyzed. Results T1S in the NG was significantly greater than in the DG (P < 0.05), while NT and C2–7 SVA in the NG were significantly lower than in the DG (P < 0.01 and P < 0.05, respectively). T1S positively correlated with CL in both groups (Pearson correlation coefficients of 0.588 in the NG and 0.504 in the DG). No significant difference was seen in TIA between the NG and DG. Conclusions T1S was involved in the occurrence and development of cervical disc degeneration, and TIA could be considered as a constant morphological parameter in both the normal population and cervical disc degeneration patients. Electronic supplementary material The online version of this article (10.1186/s12891-018-1951-8) contains supplementary material, which is available to authorized users.
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MRI kinematic analysis of T1 sagittal motion between cervical flexion and extension positions in 145 patients. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2017; 27:1034-1041. [PMID: 29128915 DOI: 10.1007/s00586-017-5385-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 09/26/2017] [Accepted: 11/05/2017] [Indexed: 10/18/2022]
Abstract
PURPOSE Although the T1 vertebra is considered as an important factor of cervical balance, little is known about its motion between flexion and extension. The purpose of present study was to analyze the T1 sagittal motion using kinematic magnetic resonance imaging (kMRI), and to identify factors that relate to T1 sagittal motion. METHODS We retrospectively analyzed 145 kMR images taken in weight-bearing neutral, flexion and extension positions. Cervical balance parameters were evaluated in each position. The degree of T1 sagittal motion was defined as [(T1 slope at extension) - (T1 slope at flexion)]. All patients were divided into three groups: Positive group (T1 followed the head motion, T1 sagittal motion > 5°), Stable group (5 ≥, ≥ - 5) and Negative group (T1 moved in the opposite direction from the head motion, > - 5). The groups were compared and multivariate logistic regression analysis was calculated. RESULTS There were 57 (40%) patients in the positive, 56 (39%) in the stable and 32 (22%) in the negative group. The positive group had the largest C2-7 sagittal vertical axis in flexion (p < 0.001) and the shortest in the extension (p = 0.023). Similar trends were seen in cranial tilt and cervical tilt. The value of T1 height < 27 mm was a significant independent factor for the negative group (p = 0.008, adjusted odds ratio = 5.958). CONCLUSION Based on T1 sagittal motion, 40% of the patients were classified in positive group (the T1 vertebra followed the head motion in flexion and extension), and 20% were classified in the negative group (the T1 vertebra moved in the opposite direction from the head motion). T1 height < 27 mm was a potential predictor of negative group.
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Paholpak P, Nazareth A, Hsieh PC, Buser Z, Wang JC. Kinematic evaluation of cervical sagittal balance and thoracic inlet alignment in degenerative cervical spondylolisthesis using kinematic magnetic resonance imaging. Spine J 2017; 17:1272-1284. [PMID: 28456677 DOI: 10.1016/j.spinee.2017.04.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 01/19/2017] [Accepted: 04/24/2017] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT T1 slope is a novel thoracic parameter used to assess cervical spine sagittal balance. Thoracic index (TI) parameters including T1 slope and cervical sagittal alignment parameters may play an important role in degenerative cervical spondylolisthesis (DCS). Current literature regarding the relationship between TI and cervical sagittal alignment parameters in patients with DCS is limited. PURPOSE (1) To evaluate the T1 slope, cervical sagittal alignment, and thoracic inlet parameter in patients with DCS using kinematic magnetic resonance imaging (kMRI), and (2) to find a correlation between the T1 slope, TI, and other cervical sagittal parameters in patients with DCS. DESIGN/SETTING Retrospective kMRI study, Level III. PATIENT SAMPLE Fifty-two patients with DCS from 1,128 patients from a cervical kMRI database. OUTCOME MEASURES T1 slope, C2-C7 angle, sagittal vertical axis C2-C7 (SVA C2-C7), cranial tilt, cervical tilt, neck tilt, and thoracic inlet angle (TIA). METHODS Cervical spine kMRIs of 52 patients with DCS (mean age 51.7±standard deviation) were analyzed in neutral, flexion, and extension positions. Patients with DCS were divided into two groups: anterolisthesis (N=33) and retrolisthesis (N=19). Each listhesis group was subclassified into grade 1 (slip 2-3 mm) and grade 2 (slip>3 mm). RESULTS Grade 2 retrolisthesis had the largest T1 slope followed by grade 1 retrolisthesis, grade 2 anterolisthesis, and grade 1 anterolisthesis. Significant differences were found between the anterolisthesis and the retrolisthesis groups in the neutral position (p=.025). The flexion position had the largest T1 slope and showed a significant difference with anterolisthesis in the neutral position (p=.041). Sagittal vertical axis C2-C7 showed strong correlation with cranial tilt in all DCS groups and all positions. CONCLUSIONS In our study, T1 slope was larger in grade 2 DCS, and the retrolisthesis group had larger T1 slope than the anterolisthesis group. Presence of larger T1 slope was significantly correlated with larger cervical lordosis curvature. Furthermore, cranial tilt was strongly correlated with SVA C2-C7.
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Yang P, Li Y, Li J, Shen Y. Impact of T1 slope on surgical and adjacent segment degeneration after Bryan cervical disc arthroplasty. Ther Clin Risk Manag 2017; 13:1119-1125. [PMID: 28894375 PMCID: PMC5584913 DOI: 10.2147/tcrm.s138990] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND This retrospective study investigated an association between preoperative T1 slope and surgical and adjacent segment degeneration (SASD) after Bryan cervical disc arthroplasty (BCDA) in patients with cervical degenerative disc disease. METHODS Based on preoperative standing lateral radiographs, 90 patients were classified according to T1 slope that was higher or lower than the 50th percentile (high T1 or low T1, 28 and 62 patients, respectively). Patients were also classified as SASD or non-SASD (38 and 52 patients, respectively) determined by radiographs at final follow-up. Visual analog scale (VAS) and Neck Disability Index (NDI) scores for neck and arm pain were noted, and changes in the sagittal alignment of the cervical spine (SACS), functional spinal unit (FSU) angle, and FSU range of motion (ROM) were also noted. Univariate and multivariate logistic regression analyses were performed to determine the risk factors for SASD. RESULTS The overall rate of SASD was 42.2% (38/90). The SACS, FSU angle, FSU ROM, and SASD rates of the high T1 and low T1 slope groups were significantly different at the last follow-up. The NDI and VAS scores of the high T1 slope group were significantly greater than those of the low T1 slope. The multivariate logistic regression analysis showed that high T1 slope and endplate coverage discrepancy (ie, residual space behind the prosthesis) were significant risk factors for SASD after BCDA. CONCLUSION High T1 slope and endplate coverage discrepancy were associated with SASD after BCDA. Patients with a high preoperative T1 slope have a smaller FSU angle and more neck pain after BCDA.
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Li J, Qin S, Li Y, Shen Y. Modic changes of the cervical spine: T1 slope and its impact on axial neck pain. J Pain Res 2017; 10:2041-2045. [PMID: 28894387 PMCID: PMC5584903 DOI: 10.2147/jpr.s144814] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Background The purpose of the research was to evaluate cervical sagittal parameters on magnetic resonance imaging (MRI) in patients with Modic changes and its impact on axial neck pain. Methods This study consisted of 266 consecutive asymptomatic or symptomatic patients with Modic changes, whose average age was 50.9±12.6 years from January 2015 to December 2016. Cervical sagittal parameters included sagittal alignment of the cervical spine (SACS), T1 slope, thoracic inlet angle (TIA), and neck tilt (NT). The Modic changes group was compared with an asymptomatic control group of 338 age- and gender-matched adults. Results In the Modic changes group, T1 slope was significantly higher (25.8°±6.3°) compared with that in the control group (22.5°±6.8°) (P=0.000). However, there was no significant difference of the NT, TIA, and SACS between the two groups. Patients in the Modic changes group were more likely to have experienced historical axial neck pain compared with the control group (P=0.000). With regard to the disc degeneration, it indicated that the disc in the Modic changes group had more severe disc degeneration (P=0.032). Conclusion T1 slope in the Modic changes group was significantly higher compared to that of the control group. The findings suggested that a higher T1 slope with broken compensation of cervical sagittal mechanism may be associated with the development of Modic changes in the cervical spine.
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Zhang L, Cheng Z, Cui Z, Ren Z, Peng B, Zhang X. [Analysis of cervical sagittal parameters on MRI in patients with cervical spondylotic myelopathy]. ZHONGGUO XIU FU CHONG JIAN WAI KE ZA ZHI = ZHONGGUO XIUFU CHONGJIAN WAIKE ZAZHI = CHINESE JOURNAL OF REPARATIVE AND RECONSTRUCTIVE SURGERY 2017; 31:451-454. [PMID: 29798611 DOI: 10.7507/1002-1892.201610119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Objective To analyse the correlation between cervical sagittal parameters of cervical spondylotic myelopathy in different sagittal curvature so as to find out representative cervical sagittal alignment parameters by measuring on MRI. Methods A retrospective analysis was made on the clinical data of 88 patients with cervical spondylotic myelopathy between July 2015 and January 2016. The C 2-C 7 Cobb angle, T 1 slope (T 1S), and C 2-C 7 sagittal vertical axis (C 2-C 7 SVA) were measured on T2-weight MRI. According to C 2-C 7 Cobb angle, the patients were divided into lordosis group (≥10° Cobb angle, 48 cases) and straightened group (0-10° Cobb angle, 40 cases). Intraclass correlation coefficient (ICC) was used for the reliability of measured data, Pearson correlation analysis for correlation between cervical sagittal parameters. Results ICC was 0.858-0.946, indicating good consistency of measurement parameters. The C 2-C 7 Cobb angle, T 1S, and C 2-C 7 SVA were (5.6±2.4)°, (22.2±6.7)°, and (10.2±5.4) mm in straightened group, and were (20.1±8.2)°, (23.4±8.9)°, and (8.2±4.6) mm in lordosis group respectively. There was no correlation between the 3 parameters in straighten group ( r=0.100, P=0.510 for T 1S and C 2-C 7 Cobb angle; r=-0.100, P=0.500 for T 1S and C 2-C 7 SVA; r=0.080, P=0.610 for C 2-C 7 Cobb angle and C 2-C 7 SVA). There was positive correlation between T 1S and C 2-C 7 Cobb angle ( r=0.540, P=0.000), negative correlation between T 1S and C 2-C 7 SVA ( r=-0.450, P=0.001), and no correlation between C 2-C 7 Cobb angle and C 2-C 7 SVA ( r=-0.003, P=0.980). Conclusion For cervical spondylotic myelopathy in patients with cervical lordosis, only T 1S measurement on MRI can be used as the main parameter to judge the sagittal curvature, but in patients with straightened cervical Cobb angle, measurements of T 1S, C 2-C 7 Cobb angle, and C 2-C 7 SVA should be taken for the comprehensive evaluation of cervical sagittal curvature.
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Kim B, Yoon DH, Ha Y, Yi S, Shin DA, Lee CK, Lee N, Kim KN. Relationship between T1 slope and loss of lordosis after laminoplasty in patients with cervical ossification of the posterior longitudinal ligament. Spine J 2016; 16:219-25. [PMID: 26523967 DOI: 10.1016/j.spinee.2015.10.042] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 09/15/2015] [Accepted: 10/22/2015] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Laminoplasty is a major surgical method used to treat patients with cervical ossification of the posterior longitudinal ligament (OPLL). Sometimes, patients with cervical OPLL demonstrate postoperative kyphosis despite sufficient preoperative lordosis. Recently, the impact of T1 slope has emerged as a predictor of kyphotic alignment change after laminoplasty. However, the relationship between T1 slope and postoperative cervical alignment change is not yet fully established. PURPOSE The goals of the present study were to investigate the relationship between T1 slope and loss of cervical lordosis (LCL), and to identify the role of T1 slope as a predictor of postoperative kyphosis after laminoplasty in patients with OPLL. STUDY DESIGN This is a retrospective case study. PATIENT SAMPLE Between January 2011 and January 2012, 64 consecutive patients who underwent cervical laminoplasty for OPLL were enrolled (male:female ratio=47:17; mean age=55.9 years). Cervical spine lateral radiographs in neutral, flexion, and extension were taken before surgery and at 2-year follow-up. OUTCOME MEASURES The C2-C7 Cobb angle, cervical range of motion (ROM), T1 slope, neck tilt, and C2-C7 sagittal vertical axis (SVA) were measured from lateral radiographs of the cervical spine preoperatively and postoperatively at 2-year follow-up. METHODS Patients were divided into two groups according to preoperative T1 slope, and the postoperative cervical alignment change was compared between the groups. Postoperative kyphosis and LCL incidence were also evaluated at 2-year follow-up. The relationships between postoperative cervical alignment change and preoperative variables, including age, T1 slope, cervical ROM, C2-C7 SVA, and T1 slope minus C2-C7 Cobb angle (T1S-CL), were investigated. RESULTS Patients were divided into two groups above and below median preoperative T1 slope (23.2°). There were no differences in age, sex, type of OPLL, or operation level between the two groups. Patients with higher preoperative T1 slope demonstrated significantly more lordotic preoperative cervical alignment (p=.001). Patients with higher preoperative T1 slope were more likely to exhibit postoperative LCL (p=.03), and when it occurred the degree of LCL was greater (p=.06). In multiple linear regression analysis, higher T1 slope (B=0.414, p=.04) and lower T1S-CL (B=-0.412, p=.03) were significantly associated with more postoperative LCL. In spite of these results, postoperative kyphosis did not occur more frequently in patients with higher T1 slope (p=.64). CONCLUSIONS Patients with higher T1 slope had more lordotic curvature before surgery and demonstrated more LCL at 2-year follow-up. Cervical alignment was compromised after laminoplasty, and the degree of LCL was correlated with preoperative T1 slope. After laminoplasty for cervical OPLL, patients with higher T1 slope tended to exhibit a greater LCL yet did not drift into frank postoperative kyphosis.
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A retrospective study to reveal the effect of surgical correction of cervical kyphosis on thoraco-lumbo-pelvic sagittal alignment. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2016; 25:2286-93. [PMID: 26810979 DOI: 10.1007/s00586-016-4392-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 01/11/2016] [Accepted: 01/15/2016] [Indexed: 12/31/2022]
Abstract
PURPOSE Recent studies suggest that cervical lordosis is influenced by thoracic kyphosis and that T1 slope is a key factor determining cervical sagittal alignment. However, no previous study has investigated the influence of cervical kyphosis correction on the remaining spinopelvic balance. The purpose of this study is to assess the effect of surgical correction of cervical kyphosis on thoraco-lumbo-pelvic alignment. METHODS Fifty-five patients who underwent ≥2 level cervical fusions for cervical radiculopathy or myelopathy were included. All patients had regional or global cervical kyphosis, which was surgically corrected into lordosis. Radiographic measurements were made using whole spine standing lateral radigraphs pre- and postoperatively to analyze various sagittal parameters. The visual analogue scale (VAS) for neck pain and the neck disability index (NDI) were calculated. The paired t test was used to compare pre- and post-operative radiographic measures and functional scores. Correlations between changes in cervical sagittal parameters and those of other sagittal parameters were analyzed by Pearson's correlation method. RESULTS Preoperative kyphosis (11.4° ± 8.3°) was corrected into lordosis (-9.3° ± 8.1°). The average fusion levels were 3.3 ± 1.0. With increasing C2-C7 lordosis after surgery (from -3.4° ± 10.0° to -15° ± 7.9°), C0-C2 lordosis decreased significantly (from -34.6° ± 8.2° to -27.7° ± 8.0°) (P < 0.001). Thoracic kyphosis (from 24.8 ± 13.9° to 33.5 ± 11.9°) and T1 slope (from 12.8° ± 7.9° to 20.4° ± 5.2°) significantly increased after surgery (P < 0.001). However, other parameters did not significantly change (P > 0.05). Neck pain VAS and NDI scores (31.8 ± 16.2) significantly improved (P < 0.001). The degree of increasing C2-C7 lordosis by surgical correction was negatively correlated with changes in both thoracic kyphosis and T1 slope (P < 0.01). CONCLUSIONS Surgical correction of cervical kyphosis affects T1 slope and thoracic kyphosis, but not lumbo-pelvic alignment. These results indicate that the compensatory mechanisms to minimize positive sagittal malalignment of the head may occur mainly in the thoracic, and not in the lumbosacral spine.
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The Use of T1 Sagittal Angle in Predicting Cervical Disc Degeneration. Asian Spine J 2015; 9:757-61. [PMID: 26435795 PMCID: PMC4591448 DOI: 10.4184/asj.2015.9.5.757] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Revised: 02/12/2015] [Accepted: 02/12/2015] [Indexed: 11/08/2022] Open
Abstract
STUDY DESIGN Retrospective evaluation. PURPOSE To analyze the effect of T1 slope on degree of degeneration in patients with cervical disc degeneration. OVERVIEW OF LITERATURE The T1 slope is well known parameter that may be very useful in evaluating sagittal balance. There are no reports on the analysis of the relationship between T1 slope and cervical disc degeneration. We hypothesized that T1 slope has an effect on the degree of cervical degeneration. METHODS Sixty patients who had cervical spine magnetic resonance imaging (MRI) in our orthopedic clinic were enrolled. Patients were divided into two groups according to T1 slope. Radiologic parameters obtained from radiography and cervical spine MRI were compared between low T1 slope group (≤25) and high T1 slope group (>25). RESULTS Among low T1 slope group, average degeneration grade of each cervical segment was 2.65 in C2-3, 2.50 in C3-4, 2.62 in C4-5, 3.23 in C5-6, and 2.81 in C6-7. And that of high T1 group was 2.35 in C2-3, 2.32 in C3-4, 2.59 in C4-5, 2.79 in C5-6, and 2.32 in C6-7. Grade of degeneration of low T1 group was significantly higher, as compared with high T1 group in C5-6 (p=0.028) and C6-7 (p=0.009). Percentage of high grade degeneration of more than grand III was 65.4% in low T1 group and 32.4% in high T1 group (p=0.018). Risk of high grade degeneration of C6-7 was significantly higher in low T1 group (odds ratio, 5.63; 95% confidence interval, 1.665-19.057; p=0.005). CONCLUSIONS Patients with low T1 slope had higher grade of degeneration regardless of age and gender. Low T1 slope is a potential risk factor of cervical spondylosis especially in the C6-7 cervical segment.
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Lee SH, Son ES, Seo EM, Suk KS, Kim KT. Factors determining cervical spine sagittal balance in asymptomatic adults: correlation with spinopelvic balance and thoracic inlet alignment. Spine J 2015; 15:705-12. [PMID: 24021619 DOI: 10.1016/j.spinee.2013.06.059] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 05/08/2013] [Accepted: 06/17/2013] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Based on the previous studies, cervical lordosis (CL) is a parameter influenced by thoracic kyphosis (TK); however, the correlations still remain unclear. Few studies have analyzed the correlations between the cervical spine lordosis and global spinopelvic balance. To date, there has been no study focused on the factors determining cervical spine sagittal balance. PATIENT SAMPLE Seventy-seven asymptomatic volunteers without the history of symptoms related to whole spine. OUTCOME MEASURES Statistical significance of correlations of radiographic parameters on cervical spine and whole-spine standing lateral radiograph. PURPOSE To analyze the factors determining cervical spine sagittal balance, including global spinopelvic balance and thoracic inlet (TI) alignment in asymptomatic adults. STUDY DESIGN A prospective radiographic study. METHODS Cervical and whole-spine standing lateral radiographs were taken to analyze the following parameters: spinopelvic parameters pelvic incidence (PI), sacral slope (SS), lumbar lordosis (LL), and TK; TI parameters thoracic inlet angle (TIA) and T1 slope; and cervical spine parameters C0-C2, C2-C7, and C0-C7 angles and cervical tilting. Statistical analysis was performed using the Pearson correlation coefficients and multiple regression analysis. RESULTS All the parameters showed a normal distribution. There was a significant sequential linkage between PI and SS (r=0.653), SS and LL (r=0.807), LL and TK (r=-0.516), and TK and C0-C7 angle (r=-0.322). There was a significant relationship between TK and T1 slope (r=0.351) but no significant relationship between TK and TIA. There were significant sequential relationships between TIA and T1 slope (r=0.694), T1 slope and C2-C7 angle (r=-0.624), and C2-C7 and C0-C2 angles (r=-0.547). T1 slope was the only parameter that demonstrated a significant correlation with both SP and TI parameters. A linear regression model showed that T1 slope had a stronger relationship with TIA (r=0.694) than TK (r=0.351). CONCLUSIONS T1 slope was a key factor determining cervical spine sagittal balance. Both spinopelvic balance and TI alignment have a significant influence on cervical spine sagittal balance via T1 slope, but TIA had a stronger effect than TK. An individual with large T1 slope required large CL to preserve physiologic sagittal balance of the cervical spine. The results of the present study could serve as baseline data for further studies on the cervical spine sagittal balance in various clinical conditions including the surgical reconstruction of lordosis.
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Park JH, Cho CB, Song JH, Kim SW, Ha Y, Oh JK. T1 Slope and Cervical Sagittal Alignment on Cervical CT Radiographs of Asymptomatic Persons. J Korean Neurosurg Soc 2013; 53:356-9. [PMID: 24003370 PMCID: PMC3756128 DOI: 10.3340/jkns.2013.53.6.356] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 04/21/2013] [Accepted: 06/19/2013] [Indexed: 12/01/2022] Open
Abstract
Objective We performed a retrospective analysis of medical records and radiographic images of patients who never underwent spinal treatment including diagnosis. The objective of this study is to explain the biomechanical and physiologic characteristics of cervical alignment related to thoracic inlet angle including T1 slope changes in each individual. Methods We reviewed the cervical CT radiographs of 80 patients who visited ENT outpatient clinic without any symptom, diagnosis and treatment of cervical spine from January 2011 to September 2012. All targeted people were randomized without any prejudice. We assessed the data-T1 slope, Cobb's angle C2-7, neck tilt, sagittal vertical axis (SVA) C2-7 and thoracic inlet angle by the CT radiographs. Results The relationships between each value were analyzed and we concluded that Cobb's angle C2-7 gets higher as the T1 slope gets higher, while the SVA C2-7 value decreases. Conclusion We propose that the T1 slope is background information in deciding how much angle can be made in the cervical spinal angle of surgical lordotic curvature, especially severe cervical deformity.
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