Cost of anterior versus posterior spinal instrumented fusion for thoracolumbar (Lenke V/VI) adolescent idiopathic scoliosis

PURPOSE: To compare direct costs associated with anterior spinal instrumented fusions (ASIF) and posterior spinal instrumented fusions (PSIF) for thoracolumbar adolescent idiopathic scoliosis (AIS). METHODS: A retrospective analysis was conducted of adolescents (ages 10-18 years) who underwent ASIF or PSIF for thoracolumbar AIS by a single surgeon. Demographics, clinical and surgical details, and inpatient post-operative outcomes were analyzed. Direct costs were obtained from medical billing data, including supplies, instrumentation, operating room services, room and board, and ICU admissions. RESULTS: 17 patients (13 girls; average age 15.3 ± 1.9 years) met inclusion criteria and were analyzed. There were no significant differences in age, major thoracolumbar Cobb angle, or thoracic Cobb angle between groups. PSIF had significantly more instrumented levels (6 ± 0.9 v. 5 levels; p < 0.01) and shorter operative times (308 ± 25.6 min vs. 447 ± 39.2 min; p < 0.01). ASIF incurred higher total costs ($72,174 ± $19,550 v. $66,552 ± $14,019; p = 0.04) and direct costs ($40,161 ± $3,668 v. $34,469 ± $7,846; p = 0.04), largely due to more ICU admissions and greater hospital lengths of stay (LOS). Excluding 2 ASIF patients with prolonged hospitalizations, direct costs between ASIF ($39,990 ± $3,855) and PSIF ($34,469 ± $7,846) were not statistically different (p > 0.05). CONCLUSIONS: While ASIF had significantly greater direct costs due to more postoperative ICU admissions and longer hospital LOS, exclusion of outliers resulted in similar average direct costs between approaches. ASIF saved one treated level on average. Number of implants, operating room services, ICU admissions and LOS are the principal drivers of cost.