There is substantial heterogeneity in the number of screws used per level fused in adolescent idiopathic scoliosis (AIS) surgery. Assuming equivalent clinical outcomes, the potential cost savings of using fewer pedicle screws were estimated using a medical decision model with sensitivity analysis.
Descriptive analyses explored the annual costs for 5710 AIS inpatient stays using discharge data from the 2009 Kids’ Inpatient Database (Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality), which is a national all-payer inpatient database. Patients between 10 and 17 years of age were identified using the ICD-9-CM code for idiopathic scoliosis (737.30). All inpatient stays were assumed to represent 10-level fusions with pedicle screws for AIS. High screw density was defined at 1.8 screws per level fused, and the standard screw density was defined as 1.48 screws per level fused. The surgical return for screw malposition was set at $23,762. A sensitivity analysis was performed by varying the cost per screw ($600–$1000) and the rate of surgical revisions for screw malposition (0.117%–0.483% of screws; 0.8%–4.3% of patients). The reported outcomes include estimated prevented malpositioned screws (set at 5.1%), averted revision surgeries, and annual cost savings in 2009 US dollars, assuming similar clinical outcomes (rates of complications, revision) using a standard- versus high-density pattern.
The total annual costs for 5710 AIS hospital stays was $278 million ($48,900 per patient). Substituting a high for a standard screw density yields 3.2 fewer screws implanted per patient, with 932 malpositioned screws prevented and 21 to 88 revision surgeries for implant malposition averted, and a potential annual cost savings of $11 million to $20 million (4%–7% reduction in the total cost of AIS hospitalizations).
Reducing the number of screws used in scoliosis surgery could potentially decrease national AIS hospitalization costs by up to 7%, which may improve the safety and efficiency of care. However, such a screw construct must first be proven safe and effective.