Postoperative Perfection: Ceiling Effects and Lack of Discrimination With Both SRS-22 and -24 Outcomes Instruments in Patients With Adolescent Idiopathic Scoliosis.

Abstract

Review of a prospective database registry. To compare the Scoliosis Research Society (SRS)-22 and SRS-24 outcomes instruments in terms of scores, rate of ceiling effects, and discriminant ability in patients with pre- and postoperative adolescent idiopathic scoliosis. Despite improvements noted with the SRS-22, the SRS-24 is still occasionally used prospectively and for comparisons with previous studies reporting SRS-24 scores. Previous work has demonstrated that postoperative scores from the 2 versions are not interchangeable. A multicenter prospective registry of patients who underwent surgical correction of adolescent idiopathic scoliosis was queried for preoperative and 2-year postoperative SRS-22 and SRS-24 scores. Scores were compared between versions and ceiling effects were identified. Groups of deformity severity were created to evaluate discriminant ability. 829 patients were identified. The SRS-22 scores for pain and general function were significantly greater than SRS-24 scores (P < 0.001), whereas the SRS-22 scores were significantly lower than the SRS-24 for self-image (P < 0.001). Preoperative ceiling effect was only noted in 1 domain each. Both versions were able to discriminate between large (80°+) and small (<45°) preoperative curves in all domains and total scores (P < 0.05). Postoperatively, the SRS-22 scores for all shared domains and total score were significantly greater than SRS-24 scores (P < 0.001). Ceiling effects in 5 of 5 domain scores were noted postoperatively for SRS-22 and in 4 of 7 for SRS-24. With a smaller range of deformity postoperatively, only the SRS-22 self-image domain was able to discriminate between large (29°+) and small (≤11°) residual curves (P < 0.05). Scores obtained by the SRS-22 and the SRS-24 are not translatable despite shared domains. Whereas both versions demonstrated preoperative discriminant ability, postoperative discrimination of residual deformity is lacking in both. Patient-reported outcomes of treatment are crucial in advancing treatment, and improvement in the ability to assess subjective outcomes is essential. 3.