Skip to main content
Log in

Analysis of the reliability of KEOPS version 2 for the measurement of coronal and sagittal parameters in spinal deformity

  • Case Series
  • Published:
Spine Deformity Aims and scope Submit manuscript



The purpose of the study is to evaluate the updated version of this software in patients with various spinal deformity.


Sixty patients were included in this study and were divided into three categories: 20 patients with AIS, 20 patients with ASD, and 20 patients having undergone corrective surgery for spinal deformity. The measurements were performed by two senior and two junior orthopedic surgery residents, and were done at two points in time separated by a 3-week interval with the cases being randomized every time to reduce the risk of memory bias. Measured parameters included coronal, sagittal, global alignment parameters, and pelvic parameters.


When assessing the inter- and intra-observer reliability across all the groups of patients, none of the coefficients was smaller than 0.8 with a very high level of agreement. The standard error ranged from 0.7° to 1.5° demonstrating a high level of accuracy. Fairly similar results were seen when the groups were divided into the three categories except for the post-operative groups where a strong and not perfect level of agreement was reported.


This is the first study to assess the reproducibility of the new version of KEOPS, showing a very high agreement in all measurements. In the post-operative group, although it showed a strong agreement, the lower performance can be explained by the presence of surgical material making it harder to identify the anatomical landmarks accurately. Nevertheless, we can recommend the usage of this software in a clinical setting.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Subscribe and save

Springer+ Basic
EUR 32.99 /Month
  • Get 10 units per month
  • Download Article/Chapter or Ebook
  • 1 Unit = 1 Article or 1 Chapter
  • Cancel anytime
Subscribe now

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3

Similar content being viewed by others

Data availability

Data is available upon reasonable request from the corresponding author.


  1. Fehlings MG, Tetreault L, Nater A et al (2015) The aging of the global population: the changing epidemiology of disease and spinal disorders. Neurosurgery 77(Suppl 4):S1-5.

    Article  PubMed  Google Scholar 

  2. Lutz W, Sanderson W, Scherbov S (2008) The coming acceleration of global population ageing. Nature 451:716–719.

    Article  CAS  PubMed  Google Scholar 

  3. Diebo BG, Shah NV, Boachie-Adjei O et al (2019) Adult spinal deformity. Lancet 394:160–172.

    Article  PubMed  Google Scholar 

  4. Smith JS, Shaffrey CI, Bess S et al (2017) Recent and Emerging Advances in Spinal Deformity. Neurosurgery 80:S70–S85.

    Article  PubMed  Google Scholar 

  5. Acaroğlu RE, Dede Ö, Pellisé F et al (2016) Adult spinal deformity: a very heterogeneous population of patients with different needs. Acta Orthop Traumatol Turc 50:57–62.

    Article  PubMed  Google Scholar 

  6. Schwab F, Dubey A, Gamez L, et al (2005) Adult scoliosis: prevalence, SF-36, and nutritional parameters in an elderly volunteer population. Spine (Phila Pa 1976) 30:1082–5.

  7. Youssef JA, Orndorff DO, Patty CA et al (2013) Current status of adult spinal deformity. Glob spine J 3:51–62.

    Article  CAS  Google Scholar 

  8. Ailon T, Smith JS, Shaffrey CI et al (2015) Degenerative spinal deformity. Neurosurgery 77(Suppl 4):S75-91.

    Article  PubMed  Google Scholar 

  9. Francis RS (1988) Scoliosis screening of 3000 college-aged women. The Utah Study–phase 2. Phys Ther 68:1513–1516

    CAS  PubMed  Google Scholar 

  10. Kebaish KM, Neubauer PR, Voros GD, et al (2011) Scoliosis in Adults Aged Forty Years and Older. Spine (Phila Pa 1976) 36:731–736.

  11. Phan P, Ouellet J, Mezghani N et al (2015) A rule-based algorithm can output valid surgical strategies in the treatment of AIS. Eur Spine J 24:1370–1381.

    Article  PubMed  Google Scholar 

  12. Sebaaly A, Grobost P, Mallam L, Roussouly P (2017) Description of the sagittal alignment of the degenerative human spine. Eur Spine J 27:489–496.

    Article  PubMed  Google Scholar 

  13. Schwab FJ, Blondel B, Bess S, et al (2013) Radiographical spinopelvic parameters and disability in the setting of adult spinal deformity: a prospective multicenter analysis. Spine (Phila Pa 1976) 38:E803–12.

  14. Diebo BG, Varghese JJ, Lafage R et al (2015) Sagittal alignment of the spine: What do you need to know? Clin Neurol Neurosurg 139:295–301.

    Article  PubMed  Google Scholar 

  15. Glassman SD, Bridwell K, Dimar JR, et al (2005) The impact of positive sagittal balance in adult spinal deformity. Spine (Phila Pa 1976) 30:2024–9.

  16. Daher M, Balmaceno-Criss M, Lafage V, et al (2023) Evolution of Distributional Alignment Goals. Semin Spine Surg 101063.

  17. Sebaaly A, Gehrchen M, Silvestre C et al (2020) Mechanical complications in adult spinal deformity and the effect of restoring the spinal shapes according to the Roussouly classification: a multicentric study. Eur Spine J 29:904–913.

    Article  PubMed  Google Scholar 

  18. Vrtovec T, Janssen MMA, Likar B et al (2013) Evaluation of pelvic morphology in the sagittal plane. Spine J 13:1500–1509.

    Article  PubMed  Google Scholar 

  19. Hwang J-H, Modi HN, Suh S-W, et al (2010) Reliability of lumbar lordosis measurement in patients with spondylolisthesis: a case-control study comparing the Cobb, centroid, and posterior tangent methods. Spine (Phila Pa 1976) 35:1691–700.

  20. Maillot C, Ferrero E, Fort D et al (2015) Reproducibility and repeatability of a new computerized software for sagittal spinopelvic and scoliosis curvature radiologic measurements: Keops®. Eur Spine J 24:1574–1581.

    Article  CAS  PubMed  Google Scholar 

  21. Dubousset J, Charpak G, Dorion I, et al (2005) [A new 2D and 3D imaging approach to musculoskeletal physiology and pathology with low-dose radiation and the standing position: the EOS system]. Bull Acad Natl Med 189:287–97; discussion 297–300

  22. Glassman SD, Berven S, Bridwell K, et al (2005) Correlation of radiographic parameters and clinical symptoms in adult scoliosis. Spine (Phila Pa 1976) 30:682–8.

  23. Akbar M, Terran J, Ames CP et al (2013) Use of Surgimap Spine in sagittal plane analysis, osteotomy planning, and correction calculation. Neurosurg Clin N Am 24:163–172.

    Article  PubMed  Google Scholar 

  24. Lafage R, Ferrero E, Henry JK et al (2015) Validation of a new computer-assisted tool to measure spino-pelvic parameters. Spine J 15:2493–2502.

    Article  PubMed  Google Scholar 

  25. Langella F, Villafañe JH, Damilano M, et al (2017) Predictive Accuracy of Surgimap Surgical Planning for Sagittal Imbalance. Spine (Phila Pa 1976) 42:E1297–E1304.

  26. Vila-Casademunt A, Pellisé F, Acaroglu E, et al (2015) The reliability of sagittal pelvic parameters: the effect of lumbosacral instrumentation and measurement experience. Spine (Phila Pa 1976) 40:E253–8.

  27. Wu W, Liang J, Du Y et al (2014) Reliability and reproducibility analysis of the Cobb angle and assessing sagittal plane by computer-assisted and manual measurement tools. BMC Musculoskelet Disord 15:33.

    Article  PubMed  PubMed Central  Google Scholar 

  28. Atici Y, Akman YE, Balioglu MB et al (2016) Two level pedicle substraction osteotomies for the treatment of severe fixed sagittal plane deformity: computer software-assisted preoperative planning and assessing. Eur Spine J 25:2461–2470.

    Article  PubMed  Google Scholar 

Download references


No funding was received for this work.

Author information

Authors and Affiliations



JR: writing original draft–approval of final version of the manuscript, agree to be accountable for the work. MD: writing original draft–approval of final version of the manuscript, agree to be accountable for the work. AH: data collection–approval of the final version of the manuscript, agree to be accountable for the work. SR: data collection–approval of the final version of the manuscript, agree to be accountable for the work. KA: data collection–approval of the final version of the manuscript, agree to be accountable for the work. AG: data collection–approval of the final version of the manuscript, agree to be accountable for the work. AS: approval of the final version of the manuscript, agree to be accountable for the work.

Corresponding author

Correspondence to Amer Sebaaly.

Ethics declarations

Conflict of interest

AS is a consultant for Medtronic (with no relation to this work). All other authors report no conflict of interest.

Ethical approval

Approval was obtained from the local ethics committee.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Rassi, J., Daher, M., Helou, A. et al. Analysis of the reliability of KEOPS version 2 for the measurement of coronal and sagittal parameters in spinal deformity. Spine Deform (2024).

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: