The Substantial Clinical Benefit Threshold for SRS-22R Domains After Surgical Treatment of Adult Spinal Deformity.

Abstract

Longitudinal cohort. To determine Substantial Clinical Benefit (SCB) thresholds for the SRS22R domains in patients undergoing adult spinal deformity surgery. The Scoliosis Research Society 22R (SRS22R) has been shown to be reliable, valid, and responsive to change in adult spinal deformity patients. Although the minimal clinically important difference (MCID) is commonly used to quantify a threshold of improvement, it could be considered a floor value rather than a goal. Patients enrolled in a prospective database of adult spinal deformity undergoing surgery with complete SRS22R preoperation and the SRS30 one-year after surgery were identified. One-year postoperative answers to the last 8 questions of the SRS30 were used as anchors to determine the SCB for the Appearance and Activity domains, Subtotal and Total Score using ROC Curve analysis. The sample population consisted of 1,422 patients; 83% were females. Mean age was 53 ± 16 years. Mean preoperative SRS22R Appearance score was 2.50 ± 0.73 improving to 3.62 ± 0.84 at one year postoperative. Mean preoperative SRS22R Activity score was 2.96 ± 0.59 improving to 3.33 ± 0.80 at one year postoperative. Mean preoperative SRS22R Pain score was 2.73 ± 0.92 improving to 3.60 ± 0.93 at one year postoperative. Mean preoperative SRS22R Subtotal was 2.56 ± 0.66 improving to 3.11 ± 0.80 at one year postoperative. There was a statistically significant difference in domain scores among the responses to the anchors (p < .001). Based on ROC analysis, SCB was 1.60 for Appearance, 0.87 for Activity, 0.69 for Subtotal, and 0.94 for Total score. The results of the current study in an adult spinal deformity population undergoing surgical treatment show SRS22R SCB values of 1.60 for Appearance, 0.87 for Activity, 0.69 for Subtotal, and 0.94 for Total score. These SCB thresholds can be used to quantify the clinical significance of health status change in the surgical management of adult spinal deformity. Level II.