226. The high vs limited screw density group in posterior fusions for adolescent idiopathic scoliosis: use of the Spine Tango registry to supplement the evidence from randomized control trials

Abstract

BACKGROUND CONTEXT Several randomized controlled trials (RCTs) have compared patient outcomes of The high screw density group(HSD) with those of limited screw density group(LSD). Because RCTs have known limitations with regard to their external validity, the comparative effectiveness of the two therapies in everyday practice remains unknown. PURPOSE This study was designed to compare patient-reported outcomes after HSD vs LSD based on data from an international spine registry. STUDY DESIGN/SETTING A retrospective analysis of registry data was performed. PATIENT SAMPLE Inclusion criteria were adolescent idiopathic scoliosis HSD or LSD, no previous surgery, and a Core Outcome Measures Index (COMI) completed at baseline and at least 3 months' follow-up. Overall, 877 patients were identified. OUTCOME MEASURES Construct characteristics and radiographic measurements were compared preoperatively and at last follow-up. Operative time and estimated costs were also evaluated. COMI score improvement were the outcome measures. METHODS Three separate analyses were performed to compare HSD and LSD surgical outcomes: (1) mimicking an RCT setting, with admission criteria typical of those in published RCTs, a 1:1 matched analysis was carried out in 797 patients; (2) an analysis was performed on 371 patients outside the classic RCT spectrum, that is, with one or more typical RCT exclusion criteria; (3) a subgroup analysis of all patients with additional follow-up longer than 2 years (n=279). RESULTS Matching resulted in 217 pairs with an average follow-up of 20 months that had no significant residual differences for any patient characteristics. Small but statistically significant differences in outcome were found in favor of HSD, which are potentially clinically relevant. Subgroup analyses of typical patients and of patients with longer-term follow-up showed no significant differences in outcome between the treatments. CONCLUSIONS The results of this observational study were in accordance with those of the published RCTs. Excellent curve correction, stability, and balance can be achieved using fewer screws than commonly used in posterior pedicle screw fusions for AIS. Operative time is reduced, and risk and cost are decreased with the use of limited screw density constructs.. Analysis of typical patients suggested that, in patients outside the spectrum of clinical trials, both surgical interventions appeared to work to a similar extent to that shown for the cohort in the matched study. Also, in the longer-term perspective, both therapies resulted in comparable benefits to the patients. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. Several randomized controlled trials (RCTs) have compared patient outcomes of The high screw density group(HSD) with those of limited screw density group(LSD). Because RCTs have known limitations with regard to their external validity, the comparative effectiveness of the two therapies in everyday practice remains unknown. This study was designed to compare patient-reported outcomes after HSD vs LSD based on data from an international spine registry. A retrospective analysis of registry data was performed. Inclusion criteria were adolescent idiopathic scoliosis HSD or LSD, no previous surgery, and a Core Outcome Measures Index (COMI) completed at baseline and at least 3 months' follow-up. Overall, 877 patients were identified. Construct characteristics and radiographic measurements were compared preoperatively and at last follow-up. Operative time and estimated costs were also evaluated. COMI score improvement were the outcome measures. Three separate analyses were performed to compare HSD and LSD surgical outcomes: (1) mimicking an RCT setting, with admission criteria typical of those in published RCTs, a 1:1 matched analysis was carried out in 797 patients; (2) an analysis was performed on 371 patients outside the classic RCT spectrum, that is, with one or more typical RCT exclusion criteria; (3) a subgroup analysis of all patients with additional follow-up longer than 2 years (n=279). Matching resulted in 217 pairs with an average follow-up of 20 months that had no significant residual differences for any patient characteristics. Small but statistically significant differences in outcome were found in favor of HSD, which are potentially clinically relevant. Subgroup analyses of typical patients and of patients with longer-term follow-up showed no significant differences in outcome between the treatments. The results of this observational study were in accordance with those of the published RCTs. Excellent curve correction, stability, and balance can be achieved using fewer screws than commonly used in posterior pedicle screw fusions for AIS. Operative time is reduced, and risk and cost are decreased with the use of limited screw density constructs.. Analysis of typical patients suggested that, in patients outside the spectrum of clinical trials, both surgical interventions appeared to work to a similar extent to that shown for the cohort in the matched study. Also, in the longer-term perspective, both therapies resulted in comparable benefits to the patients.