Best Podium presentation SOCOT (French Society of Orthopaedics and Traumatology)

Nov 17, 2011 by kikix2125

Combined evaluation of spinopelvic parameters for predicting disability in adult with spinal deformities: results of a prospective analysis

Benjamin Blondel*, Virginie Lafage, Shay Bess, Frank Schwab, Richard Hostin, Christopher Shaffrey, Justin Smith, Oheneba Boachie-Adjei, Betrand Moal, Behrooz Akbarnia, Gregory Mundis, Christopher Ames, Kebaish Kebaish, Robert Hart, Douglas Burton, Jean-Pierre Farcy.

*Corresponding author: Spine Division

306E 15th Street 10003 New-York USA

Purpose of the study

Sagittal spinal imbalance is commonly described as an increase in the distance from the C7 plumb-line to the posterosuperior edge of S1 (SVA). Nevertheless, studying this parameter alone can underestimate the importance of the imbalance. Spinopelvic parameters provide a more complete analysis but frew studies have correlated them with clinical scores. The purpose of this work was to analyse correlations between spinopelvic parameters and quality-of-life scores.

Material and methods

This study was based on the demographic, radiographic and quality-of-life data collected in consecutive parients enrolled in a prospective multicentre trial comparing surgery (OP) versus conservative (NO) treatment for the management of spinal deformity in adults. The included patients were aged >18 years and presented spinal deformities (scoliosis >20° or thoracic kyphosis >60°). Radiographic data collected were: Cobb angle, PT, SVA, discordance between pelvic incidence and lordosis. The clinical assessment used the Oswestry Disability Index (ODI) and the SRS-22r. The statistical analysis searched for correlation between radiographic parameters and quality-of-life scores to define values corresponding to a disability threshold (ODI>=40).

Results

From 2008 to 2010, 492 consecutive patients were included. Comparison between the two groups showed that the OP patients (n=178) were older (55yr vs 50.1 yr, p<0.05), had a wider SVA (5.5 vs 1.7 cm, p<0.05), higher pelvic tilt (PT22° vs 11°, p<0.05) and a greater discordance between pelvic incidence and lordosis (PI-LL 12.2 vs 4.3, p<0.05) than patients in the NO group (n=314). The OP patients presented a greater disability as measured by the clinical scores (41.4 vs 23.9, p<0.05); SRS total 2.9 vs 3.6, p<0.05). The pearson coefficient showed a strong correlation between spinopelvic parameters (PV, SVA, PI-LL) and disability in both groups (p<0.001). Linear regression analysis gave values for spinopelvic parameters corresponding to a disability defined by ODI>=40: PT>=22° (r=0.38), SVA >=46 mm (r=0.47), PI-LL>=11 (r=0.45).

Conclusions

Sagittal imbalance is disabling. The results of this prospective analysis show that a combination of spinopelvic parameters provide a means of predicting disability and thus can be used as an aid for patient evaluation. Threhold levels corresponding to severe disability were: PT>=22°, SVA>=46mm, and PI-LL>=11°.