Study design: Retrospective review of prospective case-control study.

Objective: To compare minimally invasive scoliosis surgery (MIS) and posterior spinal fusion (PSF) in a large group of patients.

Summary of background data: MIS, has been shown to have benefits over standard PSF in adolescent idiopathic scoliosis (AIS).

Methods: Radiographic, clinical, and operative review of a multi-institutional prospective database from 2013 to 2018. MIS patients with minimum 2-year XR follow up were compared with open PSF technique patients.

Results: Four hundred eighty five patients were included; 192 MIS and 293 PSF. Preoperative Cobb (P = 0.231) and kyphosis were similar (P = 0.501). Cobb correction was comparable (P = 0.46), however percent improvement in thoracic kyphosis was significantly higher in MIS (P < 0.001). MIS had significantly lower blood loss (P < 0.001), transfusions (P < 0.001), fixation points (P < 0.001), opioid consumption (P = 0.001), and hospital stay (P < 0.001). Operative time was shorter (P = 0.001) and 30-day complications rate was similar (P = 0.81).

Conclusion: This is the largest study comparing the surgical outcomes of MIS and PSF. MIS patients benefit from increased kyphosis, fewer transfusion, lower opioid consumption, and shorter hospital stay with similar Cobb correction. Increased postoperative kyphosis is likely from muscle sparing dissection in MIS.Level of Evidence: 3.