Low-Density Pedicle Screw Constructs for Adolescent Idiopathic Scoliosis: Evaluation of Effectiveness and Cost

Abstract

Study Design:Retrospective cohort study.Objective:To determine whether a low-density (LD) screw construct can achieve curve correction similar to a high-density (HD) construct in adolescent scoliosis.Methods:Patients treated operatively for idiopathic scoliosis between 2007 and 2011 were identified through a database review. A consistent LD screw construct was used. Radiographic assessment included percent correction of major and fractional lumbar curves, T5-T12 kyphosis, and angle of lowest instrumented vertebra (LIV). Costs were compared with HD constructs.Results:Thirty-five patients were included in the analysis. Ages ranged from 12 to 19 years (mean = 14.9 years). Average screw density was 1.2 screws per level (range = 1.07-1.5 screws). Mean percent curve correction at latest follow-up: major curve, 66.9%; fractional lumbar curve, 63%. Average postoperative thoracic kyphosis: 29.5°. Mean LIV angle: 5.6°. Average construct cost was $14 871 per case compared with $23 840 per case if all levels had been instrumented with 2 screws, amounting to an average savings of $9000.Conclusions:Our LD screw construct is among the lowest density constructs reported and achieves curve correction comparable to HD constructs at substantially lower cost.

Reciprocal Changes in Sagittal Alignment in Adolescent Idiopathic Scoliosis Patients Following Strategic Pedicle Screw Fixation

“…In the present study, we achieved 67% correction in coronal plane with a primary curve flexibility of 41% and an implant density of 68%. Our results are comparable to studies conducted by Morr et al [ 17 ] and Tannous et al [ 18 ], in which they reported 66.6% and 66.9% improvements in the primary curve, respectively. In comparison to Davis [ 7 ], we achieved better coronal correction attributable to increased implant density in the present study.…”

Radiological outcomes of the selective spinal fusion for lenke type 5C adolescent idiopathic scoliosis

“…Chen J et al 19 in a retrospective review of 39 patients noted a positive correlation between implant density and curve correction. Sariylimaz & Ozkunt 20 in their comparative study and Tannous et al 21 in their retrospective study documented that curve correction in high versus low implant density had no significant correlation between Cobb angle correction and implant density. Our study had a few limitations such as the small number of patients and retrospective nature of our study design.…”

Post-marketing surveillance on safety and efficacy of posterior spinal correction and fusion with the CD Horizon Solera instrumentation for adolescent idiopathic scoliosis. A retrospective cohort study

“…In all-screw constructs, literature describes different results on curve correction. Some find a significantly higher curve correction in high-density constructs, while other studies contradict this [21,24,[33][34][35][36][37][38][39][40]. This may be caused by the flexibility of the curves and screw position [38][39][40][41].…”