Polyaxial Screws with Thick Rod versus Monoaxial Screws with Thin Rod in Video-Assisted Thoracoscopic Scoliosis Surgery (VATS)

Abstract

were included in the study (mono-axial screws and a 4.5 mm rod: thin rod group=19 cases; poly-axial reduction screws and a 5.5 mm diameter rod: thick rod group=20 cases). All patients were followed for over 2 years postoperatively. For the comparison of surgical outcomes between the two groups, radiographic measurements were performed in the coronal and sagittal planes.Results: Preoperative scoliosis angle (thin rod group 49.8。 , thick rod group 47.1。 ), age, BMI, Risser stage, union time, operative time, and blood loss showed no statistical difference between the two groups. Postoperative average correction rate of scoliosis angle was 69% (15.8。 ) in the thin rod group and 70% (14.1。 ) in the thick rod group. However, correction rate after 2 years was 51% (24.5。 ) in the thin rod group and 60% (18.7。 ) in the thick rod group, showing statistically significant difference. There was a tendency toward correction loss in the thin rod group (8.7。 vs. 4.6。p=0.0057).Conclusion: Postoperative correction rate was satisfactory in both groups. However, the thin rod group showed substantial correction loss. Therefore, poly-axial screws and thick rods are more suitable in VATS correction of scoliosis.