O0818 Oct.3: 4:20pm - AIS Patients Demonstrate Better Outcomes in MIS Compared to Standard Surgery

Minimally invasive scoliosis surgery (MIS), in smaller studies, has been shown to have significant benefits over standard posterior spinal fusion (PSF) in adolescent idiopathic scoliosis (AIS). This study seeks to compare the two procedures in a large group of patients.
Retrospective review of a multi-institutional prospective database was performed. Radiographic, clinical, and operative data were collected for MISS patients (2008-2019) and PSF (2013 to 2019). Data is presented as Median (IQR).
330 PSF and 218 MIS patients were compared. There was no significant difference between the groups with respect to age (p = 0.12), but PSF patients had significantly higher BMI (p<0.001). Preoperative Cobb (0.80) and preoperative kyphosis (p = 0.75) were similar. Postoperative Cobb (p=0.41) and overall Cobb correction (p=0.64) were similar. Interestingly, postoperative kyphosis was significantly higher in the MIS group (p<0.001), as was the percentage change of kyphosis (p<0.001).
MIS patients had significantly fewer levels fused (p<0.001) and fewer fixation points (p<0.001), while having longer operative times (p<0.001). Estimated blood loss (p<0.001) was significantly less and length of stay (p<0.001) ass significantly shorter for MIS patients.
Perioperative complication rate (within 90 days of surgery) was similar between the groups (p=0.84).
This is the largest study comparing the surgical outcomes of MISS and PSF. MISS patients seem to benefit from less blood loss, and shorter hospital stay with similar Cobb correction and operative time. The biggest advantage may be significantly more kyphosis, which we believe is due to the muscle saving dissection of MISS.