Multicenter validation of a formula predicting postoperative spinopelvic alignment Clinical article

Virginie Lafage, Neil J. Bharucha, Frank Schwab, Robert A. Hart, Douglas Burton, Oheneba Boachie-Adjei, Justin S. Smith, Richard Hostin, Christopher Shaffrey, Munish Gupta, Behrooz A. Akbarnia, Shay Bess

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

Object. Sagittal spinopelvic imbalance is a major contributor to pain and disability for patients with adult spinal deformity (ASD). Preoperative planning is essential for pedicle subtraction osteotomy (PSO) candidates; however, current methods are often inaccurate because no formula to date predicts both postoperative sagittal balance and pelvic alignment. The authors of this study aimed to evaluate the accuracy of 2 novel formulas in predicting postoperative spinopelvic alignment after PSO. Methods. This study is a multicenter retrospective consecutive PSO case series. Adults with spinal deformity (> 21 years old) who were treated with a single-level lumbar PSO for sagittal imbalance were evaluated. All patients underwent preoperative and a minimum of 6-month postoperative radiography. Two novel formulas were used to predict the postoperative spinopelvic alignment. The results predicted by the formulas were then compared with the actual postoperative radiographic values, and the formulas' ability to identify successful (sagittal vertical axis [SVA] ≤ 50 mm and pelvic tilt [PT] ≤ 25°) and unsuccessful (SVA > 50 mm or PT > 25°) outcomes was evaluated. Results. Ninety-nine patients met inclusion criteria. The median absolute error between the predicted and actual PT was 4.1° (interquartile range 2.0°-6.4°). The median absolute error between the predicted and actual SVA was 27 mm (interquartile range 11-47 mm). Forty-one of 54 patients with a formula that predicted a successful outcome had a successful outcome as shown by radiography (positive predictive value = 0.76). Forty-four of 45 patients with a formula that predicted an unsuccessful outcome had an unsuccessful outcome as shown by radiography (negative predictive value = 0.98). Conclusions. The spinopelvic alignment formulas were accurate when predicting unsuccessful outcomes but less reliable when predicting successful outcomes. The preoperative surgical plan should be altered if an unsuccessful result is predicted. However, even after obtaining a predicted successful outcome, surgeons should ensure that the predicted values are not too close to unsuccessful values and should identify other variables that may affect alignment. In the near future, it is anticipated that the use of these formulas will lead to better surgical planning and improved outcomes for patients with complex ASD.

Original languageEnglish (US)
Pages (from-to)15-21
Number of pages7
JournalJournal of Neurosurgery: Spine
Volume16
Issue number1
DOIs
StatePublished - Jan 2012

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Osteotomy
Radiography
Aptitude
Pain

Keywords

  • Adult spinal deformity
  • Balance formula
  • Degenerative
  • Pedicle subtraction osteotomy
  • Pelvic tilt
  • Sagittal realignment

ASJC Scopus subject areas

  • Clinical Neurology
  • Surgery
  • Neurology

Cite this

Lafage, V., Bharucha, N. J., Schwab, F., Hart, R. A., Burton, D., Boachie-Adjei, O., ... Bess, S. (2012). Multicenter validation of a formula predicting postoperative spinopelvic alignment Clinical article. Journal of Neurosurgery: Spine, 16(1), 15-21. https://doi.org/10.3171/2011.8.SPINE11272

Multicenter validation of a formula predicting postoperative spinopelvic alignment Clinical article. / Lafage, Virginie; Bharucha, Neil J.; Schwab, Frank; Hart, Robert A.; Burton, Douglas; Boachie-Adjei, Oheneba; Smith, Justin S.; Hostin, Richard; Shaffrey, Christopher; Gupta, Munish; Akbarnia, Behrooz A.; Bess, Shay.

In: Journal of Neurosurgery: Spine, Vol. 16, No. 1, 01.2012, p. 15-21.

Research output: Contribution to journalArticle

Lafage, V, Bharucha, NJ, Schwab, F, Hart, RA, Burton, D, Boachie-Adjei, O, Smith, JS, Hostin, R, Shaffrey, C, Gupta, M, Akbarnia, BA & Bess, S 2012, 'Multicenter validation of a formula predicting postoperative spinopelvic alignment Clinical article', Journal of Neurosurgery: Spine, vol. 16, no. 1, pp. 15-21. https://doi.org/10.3171/2011.8.SPINE11272
Lafage, Virginie ; Bharucha, Neil J. ; Schwab, Frank ; Hart, Robert A. ; Burton, Douglas ; Boachie-Adjei, Oheneba ; Smith, Justin S. ; Hostin, Richard ; Shaffrey, Christopher ; Gupta, Munish ; Akbarnia, Behrooz A. ; Bess, Shay. / Multicenter validation of a formula predicting postoperative spinopelvic alignment Clinical article. In: Journal of Neurosurgery: Spine. 2012 ; Vol. 16, No. 1. pp. 15-21.
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AU - Hostin, Richard

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N2 - Object. Sagittal spinopelvic imbalance is a major contributor to pain and disability for patients with adult spinal deformity (ASD). Preoperative planning is essential for pedicle subtraction osteotomy (PSO) candidates; however, current methods are often inaccurate because no formula to date predicts both postoperative sagittal balance and pelvic alignment. The authors of this study aimed to evaluate the accuracy of 2 novel formulas in predicting postoperative spinopelvic alignment after PSO. Methods. This study is a multicenter retrospective consecutive PSO case series. Adults with spinal deformity (> 21 years old) who were treated with a single-level lumbar PSO for sagittal imbalance were evaluated. All patients underwent preoperative and a minimum of 6-month postoperative radiography. Two novel formulas were used to predict the postoperative spinopelvic alignment. The results predicted by the formulas were then compared with the actual postoperative radiographic values, and the formulas' ability to identify successful (sagittal vertical axis [SVA] ≤ 50 mm and pelvic tilt [PT] ≤ 25°) and unsuccessful (SVA > 50 mm or PT > 25°) outcomes was evaluated. Results. Ninety-nine patients met inclusion criteria. The median absolute error between the predicted and actual PT was 4.1° (interquartile range 2.0°-6.4°). The median absolute error between the predicted and actual SVA was 27 mm (interquartile range 11-47 mm). Forty-one of 54 patients with a formula that predicted a successful outcome had a successful outcome as shown by radiography (positive predictive value = 0.76). Forty-four of 45 patients with a formula that predicted an unsuccessful outcome had an unsuccessful outcome as shown by radiography (negative predictive value = 0.98). Conclusions. The spinopelvic alignment formulas were accurate when predicting unsuccessful outcomes but less reliable when predicting successful outcomes. The preoperative surgical plan should be altered if an unsuccessful result is predicted. However, even after obtaining a predicted successful outcome, surgeons should ensure that the predicted values are not too close to unsuccessful values and should identify other variables that may affect alignment. In the near future, it is anticipated that the use of these formulas will lead to better surgical planning and improved outcomes for patients with complex ASD.

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KW - Adult spinal deformity

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KW - Pedicle subtraction osteotomy

KW - Pelvic tilt

KW - Sagittal realignment

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