European Spine Journal

, Volume 23, Supplement 6, pp 587–596 | Cite as

Successful correction of sagittal imbalance can be calculated on the basis of pelvic incidence and age

  • Pedro Berjano
  • Francesco Langella
  • Maryem-Fama Ismael
  • Marco Damilano
  • Sergio Scopetta
  • Claudio Lamartina
Original Article



Sagittal imbalance is an independent predictor of outcome in adult degenerative spinal deformity. Restoration of sagittal spinopelvic parameters correlates with a better postoperative outcome. Several methods of preoperative calculation for sagittal correction have been proposed, most of them are geometrical. A non-geometrical method, based on data of spinopelvic relationships in normal subjects that uses the patient’s pelvic incidence and age to calculate target lumbar lordosis and thoracic kyphosis is proposed. The goal of this study is to describe and validate this non-geometrical method in terms of sensitivity and specificity to predict satisfactory spinopelvic alignment.

Materials and methods

Retrospective cohort study of patients operated for sagittal imbalance with pedicle subtraction osteotomies (PSO). Two calculation algorithms [method a: LL = −(32.56 + PI × 0.54), method b: LL = −(PI + 10°)]; in both TK = (PI/r)-LL, see text for definitions] obtain theoretical lumbar lordosis (LL) and thoracic kyphosis (TK) solely based on pelvic incidence and age, for surgical planning. The sample is categorized according to two parameters: planning goals (LL and TK) achieved or not and satisfactory alignment (SVA < 50 mm and PT < 20°) achieved or not. 2 × 2 tables are built and odds ratio, sensitivity and specificity and predictive positive value/predictive negative value (PPV/NPV) are calculated for each planning method. Different levels of tolerance for undercorrection are analyzed to refine the use of the method.


Of the 50 patients included in the study, 23 presented satisfactory alignment postoperatively. With a tolerance of hypocorrection of 10° (LL) and 30° (TK), correction target was achieved in 23 patients according to method a [S = 0.89, Sp = 0.87 %, OR 53.33 (95 % CI 9.677–293.931), p < 0.001], 23 patients according to method b [S = 0.93, Sp = 0.91, OR 131.25 (95 % CI 17–1013), p < 0.001]. The best prediction of satisfactory alignment was obtained with method b and tolerance 0° (LL) and 10° (TK). All patients with complete correction of LL (both methods) achieved good alignment. 22/24 (91 %) patients with less than 10° of undercorrection of LL (method b) achieved good alignment.


Calculation of the target lordosis and kyphosis based only in the value of PI and age is a reliable method that can predict good outcomes in terms of alignment. The rule LL = −(PI + 10°) is an easy to calculate and very effective method of planning for lumbar lordosis and good alignment can be expected with high confidence when the final lordosis is within 10° of undercorrection. Including TK in surgical planning can improve the results in terms of restoration of the less known “spinopelvic balance” parameter.


Sagittal deformity Pedicle subtraction osteotomy Calculation method Surgical planning Sagittal imbalance 


Conflict of interest

None of the authors has any potential conflict of interest.


  1. 1.
    Dubusset J (1994) Three-dimensional analysis of the scoliotic deformity. In: Weinstein SL (ed) Pediatric spine: principle and practice. Raven Press, New YorkGoogle Scholar
  2. 2.
    Lafage V, Schwab F, Vira S, Patel A, Ungar B, Farcy JP (2011) Spino-pelvic parameters after surgery can be predicted: a preliminary formula and validation of standing alignment. Spine 3:1037–1045CrossRefGoogle Scholar
  3. 3.
    Smith JS, Shaffrey CI, Glassman SD, Berven SH, Schwab FJ, Hamill CL, Horton WC, Ondra SL, Sansur CA, Bridwell KH, Spinal Deformity Study Group (2011) Risk–benefit assessment of surgery for adult scoliosis: an analysis based on patient age. Spine 36:817–824PubMedCrossRefGoogle Scholar
  4. 4.
    Glassman SD, Berven S, Bridwell K et al (2005) Correlation of radiographic parameters and clinical symptoms in adult scoliosis. Spine 30:682–688PubMedCrossRefGoogle Scholar
  5. 5.
    Glassman SD, Bridwell K, Dimar JR et al (2005) The impact of positive sagittal balance in adult spinal deformity. Spine 30:2024–2029PubMedCrossRefGoogle Scholar
  6. 6.
    Van Royen BJ, Scheerder FJ, Jansen E, Smit TH (2007) ASKyphoplan: a program for deformity planning in ankylosing spondylitis. Eur Spine J 16:1445–1449PubMedCrossRefPubMedCentralGoogle Scholar
  7. 7.
    Gill JB, Levin A, Burd T, Longley M (2008) Corrective osteotomies in spine surgery. J Bone Joint Surg Am 90:2509–2520PubMedCrossRefGoogle Scholar
  8. 8.
    Le Huec JC, Leijssen P, Duarte M, Aunoble S (2011) Thoracolumbar imbalance analysis for osteotomy planification using a new method: FBI technique. Eur Spine J Suppl 5:S669–S680CrossRefGoogle Scholar
  9. 9.
    Yang BP, Ondra SL (2006) A method for calculating the exact angle required during pedicle subtraction osteotomy for fixed sagittal deformity: comparison with the trigonometric method. Oper Neurosurg 59:458–463Google Scholar
  10. 10.
    Neal CJ, McClendon J, Halpin R, Acosta FL, Koski T, Ondra SL (2011) Predicting ideal spinopelvic balance in adult spinal deformity. J Neurosurg Spine 15:82–91PubMedCrossRefGoogle Scholar
  11. 11.
    Berjano P, Cecchinato R, Damilano M, Morselli C, Sansone V, Lamartina C (2013) Preoperative calculation of the necessary correction in sagittal imbalance surgery: validation of three predictive methods. Eur Spine J 22(Suppl 6):S847–S852PubMedCrossRefGoogle Scholar
  12. 12.
    Rose PS, Bridwell KH, Lenke LG, Cronen GA, Mulconrey DS, Buchowski JM, Kim YJ (2009) Role of pelvic incidence, thoracic kyphosis, and patient factors on sagittal plane correction following pedicle subtraction osteotomy. Spine (Phila Pa 1976) 34(8):785–791CrossRefGoogle Scholar
  13. 13.
    Ondra SL, Marzouk S, Koski T, Silva F, Salehi S (2006) Mathematical calculation of pedicle subtraction osteotomy size to allow precision correction of fixed sagittal deformity. Spine 31:E973–E979PubMedCrossRefGoogle Scholar
  14. 14.
    Lamartina C, Berjano P, Petruzzi M, Sinigaglia A, Casero G, Cecchinato R, Damilano M, Bassani R (2012) Criteria to restore the sagittal balance in deformity and degenerative spondylolisthesis. Eur Spine J 21(Suppl 1):S27–S31PubMedCrossRefGoogle Scholar
  15. 15.
    Gill JB, Levin A, Burd T, Longley M (2008) Corrective osteotomies in spine surgery. J Bone Joint Surg Am 90:2509–2520PubMedCrossRefGoogle Scholar
  16. 16.
    Legaye J, Duval-Beaupere G (2005) Sagittal plane alignment of the spine and gravity: a radiological and clinical evaluation. Acta Orthop Belg 71:213–220PubMedGoogle Scholar
  17. 17.
    Legaye J, Duval-Beaupère G, Hecquet J, Marty C (1998) Pelvic incidence: a fundamental pelvic parameter for three-dimensional regulation of spinal sagittal curves. Eur Spine J 7:99–103PubMedCrossRefPubMedCentralGoogle Scholar
  18. 18.
    Aurouer N, Obeid I, Gille O, Pointillart V, Vital JM (2009) Computerized preoperative planning for correction of sagital deformity of the spine. Surg Radiol Anat 31:781–792PubMedCrossRefGoogle Scholar
  19. 19.
    Lamartina C, Berjano P (2014) Classification of sagittal imbalance based on spinal alignment and compensatory mechanisms. Eur Spine J. doi: 10.1007/s00586-014-3227-9 Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Pedro Berjano
    • 1
  • Francesco Langella
    • 2
  • Maryem-Fama Ismael
    • 1
  • Marco Damilano
    • 1
  • Sergio Scopetta
    • 1
    • 3
  • Claudio Lamartina
    • 4
  1. 1.IVth Spine Surgery DivisionIRCCS Istituto Ortopedico GaleazziMilanItaly
  2. 2.Orthopaedic DivisionIInd University of NaplesNaplesItaly
  3. 3.Casa di Cura Villa SalusBattipagliaItaly
  4. 4.IInd Spine Surgery DivisionIRCCS Istituto Ortopedico GaleazziMilanItaly

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