Research in Adolescent Idiopathic Scoliosis

The Deformity-Flexibility Quotient Predicts Both Patient Satisfaction and Surgeon Preference in the Treatment of Lenke 1B or 1C Curves for Adolescent Idiopathic Scoliosis

Newton, Peter O. MD*†; Upasani, Vidyadhar V. MD†; Bastrom, Tracey P. MA*; Marks, Michelle C. PT, MA*

Study Design. Analysis of patient and surgeon preference between selective and nonselective thoracic spinal fusions.

Objective. The purpose of this study was: (1) to determine patient preference between a longer, straighter fusion versus a shorter fusion with a residual lumbar deformity, and (2) to determine surgeon preference based on a cross-sectional survey.

Summary of Background Data. In the surgical treatment of Lenke 1B and 1C curves, choosing between a selective thoracic fusion which may leave residual lumbar deformity versus a fusion into the lower lumbar spine which may improve correction at the expense of lumbar motion continues to be debated.

Methods. The deformity-flexibility quotient (DFQ) was defined to quantify the 2 primary yet competing goals of adolescent idiopathic scoliosis surgery, and is calculated by dividing the residual coronal lumbar deformity by the number of unfused distal motion segments. Patient preference between a selective versus nonselective fusion was determined using a Spearman’s Rho analysis to correlate radiographic data (including the DFQ) with Scoliosis Research Society-24 scores. Surgeon preference was determined using a cross-sectional survey of 12 experienced scoliosis surgeons.

Results. One hundred fifty-five adolescent idiopathic scoliosis patients were included in the analysis. At 2-year postoperative, the number of distal unfused motion segments averaged 5.8 ± 1.4 (range: 2–9) and the residual thoracolumbar/lumbar deformity averaged 20.1° ± 8.8° (range: 1°–43°). This resulted in an average DFQ of 3.6 ± 1.9 (range: 0.2–12.3). A lower DFQ was found to significantly correlate with improved patient satisfaction scores (r = −0.16, P = 0.04). In the cross-sectional survey, a lower DFQ also predicted the surgeon preferred radiograph in greater than 70% of the pairings.

Conclusion. The DFQ quantifies the perceived trade off between residual deformity and spared motion segments. Two-year postoperative patient satisfaction, as measured by the Scoliosis Research Society-24 questionnaire, and surgeon preference, in terms of coronal radiographic outcome, correlated significantly with the DFQ.


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Spine: 1 May 2009 – Volume 34 – Issue 10 – pp 1032-1039