Sagittal balance of the cervical spine: an analysis of occipitocervical and spinopelvic interdependence, with C-7 slope as a marker of cervical and spinopelvic alignment

Núñez-Pereira, Susana; Hitzl, Wolfgang; Bullmann, Viola; Meier, Oliver; Koller, Heiko

doi:10.3171/2014.11.spine14368

Cited by 96 publications

(70 citation statements)

References 23 publications

(25 reference statements)

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“…In particular, cervical alignment has been suggested as an important factor associated with neck pain. 9,15,20,23 We sought to assess whether LPSF allows for greater neck pain relief when compared with laminoplasty for multilevel CSM in cohorts of patients with similar postoperative cervical lordosis. This study compared perioperative and followup outcomes of patients with matched cervical sagittal alignment who had undergone either laminoplasty or LPSF.…”

mentioning

confidence: 99%

Laminoplasty versus laminectomy with posterior spinal fusion for multilevel cervical spondylotic myelopathy: influence of cervical alignment on outcomes

Lau

Winkler

Than

et al. 2017

Journal of Neurosurgery: Spine

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OBJECTIVECervical curvature is an important factor when deciding between laminoplasty and laminectomy with posterior spinal fusion (LPSF) for cervical spondylotic myelopathy (CSM). This study compares outcomes following laminoplasty and LPSF in patients with matched postoperative cervical lordosis.METHODSAdults undergoing laminoplasty or LPSF for cervical CSM from 2011 to 2014 were identified. Matched cohorts were obtained by excluding LPSF patients with postoperative cervical Cobb angles outside the range of laminoplasty patients. Clinical outcomes and radiographic results were compared. A subgroup analysis of patients with and without preoperative pain was performed, and the effects of cervical curvature on pain outcomes were examined.RESULTSA total of 145 patients were included: 101 who underwent laminoplasty and 44 who underwent LPSF. Preoperative Nurick scale score, pain incidence, and visual analog scale (VAS) neck pain scores were similar between the two groups. Patients who underwent LPSF had significantly less preoperative cervical lordosis (5.8° vs 10.9°, p = 0.018). Preoperative and postoperative C2–7 sagittal vertical axis (SVA) and T-1 slope were similar between the two groups. Laminoplasty cases were associated with less blood loss (196.6 vs 325.0 ml, p < 0.001) and trended toward shorter hospital stays (3.5 vs 4.3 days, p = 0.054). The perioperative complication rate was 8.3%; there was no significant difference between the groups. LPSF was associated with a higher long-term complication rate (11.6% vs 2.2%, p = 0.036), with pseudarthrosis accounting for 3 of 5 complications in the LPSF group. Follow-up cervical Cobb angle was similar between the groups (8.8° vs 7.1°, p = 0.454). At final follow-up, LPSF had a significantly lower mean Nurick score (0.9 vs 1.4, p = 0.014). Among patients with preoperative neck pain, pain incidence (36.4% vs 31.3%, p = 0.629) and VAS neck pain (2.1 vs 1.8, p = 0.731) were similar between the groups. Similarly, in patients without preoperative pain, there was no significant difference in pain incidence (19.4% vs 18.2%, p = 0.926) and VAS neck pain (1.0 vs 1.1, p = 0.908). For laminoplasty, there was a significant trend for lower pain incidence (p = 0.010) and VAS neck pain (p = 0.004) with greater cervical lordosis, especially when greater than 20° (p = 0.011 and p = 0.018). Mean follow-up was 17.3 months.CONCLUSIONSFor patients with CSM, LPSF was associated with slightly greater blood loss and a higher long-term complication rate, but offered greater neurological improvement than laminoplasty. In cohorts of matched follow-up cervical sagittal alignment, pain outcomes were similar between laminoplasty and LPSF patients. However, among laminoplasty patients, greater cervical lordosis was associated with better pain outcomes, especially for lordosis greater than 20°. Cervical curvature (lordosis) should be considered as an important factor in pain outcomes following posterior decompression for multilevel CSM.

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confidence: 99%

Laminoplasty versus laminectomy with posterior spinal fusion for multilevel cervical spondylotic myelopathy: influence of cervical alignment on outcomes

Lau

Winkler

Than

et al. 2017

Journal of Neurosurgery: Spine

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“…Given the proximity of C7 to T1, several studies have suggested the use of C7 slope as a potential substitute for T1 slope in the assessment of cervical sagittal balance. [17][18][19] The more cephalad anatomical location of C7 makes it less susceptible to being obscured by the shoulders or thoracic trunk on lateral radiographs when patients are positioned in the standardized upright manner for radiographs. In this study, the endplates of C7 were indeed more easily visualized than the superior endplate of T1.…”

Section: Discussionmentioning

confidence: 99%

“…13,14 To address these limitations, several authors have suggested using C7 slope as a proxy for T1 slope when the T1 superior endplate cannot be adequately visualized on radiographs. [15][16][17][18][19] The purpose of this study was 2-fold. First, we aimed to assess the correlation between C7 slope and T1 slope on upright radiographs.…”

Section: Introductionmentioning

confidence: 99%

Can C7 Slope Be Used as a Substitute for T1 Slope? A Radiographic Analysis

Tang

Cheung

et al. 2019

Global Spine Journal

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Study Design: Retrospective radiographic study. Objectives: T1 slope is an important parameter of sagittal spinal balance. However, the T1 superior endplate can be difficult to visualize on radiographs due to overlying anatomical structures. C7 slope has been proposed as a potential substitute for T1 slope when the T1 superior endplate is not well visualized. The objective of this study was 2-fold: (1) to assess the correlation between C7 and T1 slopes on upright cervical spine radiographs and (2) to evaluate the interrater reliability of C7 slope. Methods: Cervical spine radiographs taken between December 2017 and June 2018 at a single institution were reviewed. Two observers measured upper C7 slope, lower C7 slope, and T1 slope. The correlations between upper and lower C7 slope and T1 slope were evaluated, and linear regression analyses were performed. Interrater reliability of C7 slope was also assessed. Results: In this cohort of 152 patients, there was a strong correlation between upper C7 slope and T1 slope ( r = 0.91, P < .001), as well as between lower C7 slope and T1 slope ( r = 0.90, P < .001). T1 slope could be estimated from the linear regression equation, T1 slope = 0.87 × C7 slope + 7, with an overall model fit of R 2 = 0.8. There was strong interrater reliability for upper (intraclass correlation coefficient [ICC] = 0.95, P < .001) and lower C7 slope (ICC = 0.96, P < .001). Conclusions: Both the upper and lower C7 slope are strongly correlated with T1 slope and can be used as a substitute to estimate T1 slope when the superior endplate of T1 is not well visualized.

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“…Both C2-7 SVA and Cobb angle have been previously shown to correlate with radiographic failure and worse HRQOL; however, the C2-3 disc angle is a radiographic measure that has been minimally investigated to this point. 1,30,32,33,37,42,44 A study by Katsumi et al investigated the incidence of postoperative deformity leading to instability after decompression via laminectomy was performed in the cervical spine. 23 The authors demonstrated the presence of cervical instability at the C2-3 disc space after C2 laminectomy and that the C2-3 disc angle increased from 5.5° to 14.5°.…”

Section: Discussionmentioning

confidence: 99%

The effect of C2–3 disc angle on postoperative adverse events in cervical spondylotic myelopathy

Lee

Walsh

Lubelski

et al. 2019

Journal of Neurosurgery: Spine

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OBJECTIVEComplete radiographic and clinical evaluations are essential in the surgical treatment of cervical spondylotic myelopathy (CSM). Prior studies have correlated cervical sagittal imbalance and kyphosis with disability and worse health-related quality of life. However, little is known about C2–3 disc angle and its correlation with postoperative outcomes. The present study is the first to consider C2–3 disc angle as an additional radiographic predictor of postoperative adverse events.METHODSA retrospective chart review was performed to identify patients with CSM who underwent surgeries from 2010 to 2014. Data collected included demographics, baseline presenting factors, and postoperative outcomes. Cervical sagittal alignment variables were measured using the preoperative and postoperative radiographs. Univariable logistic regression analyses were used to explore the association between dependent and independent variables, and a multivariable logistic regression model was created using stepwise variable selection.RESULTSThe authors identified 171 patients who had complete preoperative and postoperative radiographic and outcomes data. The overall rate of postoperative adverse events was 33% (57/171), and postoperative C2–3 disc angle, C2–7 sagittal vertical axis, and C2–7 Cobb angle were found to be significantly associated with adverse events. Inclusion of postoperative C2–3 disc angle in the analysis led to the best prediction of adverse events. The mean postoperative C2–3 disc angle for patients with any postoperative adverse event was 32.3° ± 17.2°, and the mean for those without any adverse event was 22.4° ± 11.1° (p < 0.0001).CONCLUSIONSIn the present retrospective analysis of postoperative adverse events in patients with CSM, the authors found a significant association between C2–3 disc angle and postoperative adverse events. They propose that C2–3 disc angle be used as an additional parameter of cervical spinal sagittal alignment and predictor for operative outcomes.

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Sagittal balance of the cervical spine: an analysis of occipitocervical and spinopelvic interdependence, with C-7 slope as a marker of cervical and spinopelvic alignment

Cited by 96 publications

References 23 publications

Laminoplasty versus laminectomy with posterior spinal fusion for multilevel cervical spondylotic myelopathy: influence of cervical alignment on outcomes

Laminoplasty versus laminectomy with posterior spinal fusion for multilevel cervical spondylotic myelopathy: influence of cervical alignment on outcomes

Can C7 Slope Be Used as a Substitute for T1 Slope? A Radiographic Analysis

The effect of C2–3 disc angle on postoperative adverse events in cervical spondylotic myelopathy

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