Treatment of Adolescent Idiopathic Scoliosis with Pedicle Screw-Only Constructs: Minimum 3-Year Follow-Up of 103 Consecutive Cases

Methods: 103 consecutive AIS patients with a minimum 3-yr-follow-up (mean=4.8; range=3.01-7.30 years) were evaluated. Radiographic measurements (AP,LAT,supine,side-bending films) included preoperative (PreO), postoperative(PO), 2-year (2Yr) and final follow-up (FFU). Chart review evaluated: PFTs, SRS scores, presence of thoracoplasty, Lenke classification and complications.

Results: The average age at time of surgery was 15.1+2.2years. The most frequent curve type was Lenke Type1 (40.24%), followed by Lenke Type3 (26.83%). The average main thoracic (MT) curve measured 59.2 +12.2SD (PreO), and corrected to 16.8 +9.9SD (PO) (p<0 .0001). Thoracic kyphosis (T5-12) decreased from 25.81° to 15.5° at FFU (p="0.004)" Nash-Moe grading for apical vertebral rotation (AVR) in the MT curve 2.04 (PreOp) 1.09 (p<0.0001), while AVR TL/L spine 1.6 1.14 (p<0.0001). Importantly, horizontalization of subjacent lower disc measured (-8.32°) PreO and (-0.94°) PO (p<0.001). Finally, clavicle-angle (a) improved (-2.20°) 1.14° PFTs follow-up averaged 2.44yrs with improvement FVC 7.1% FEV1 8.8% (P<0.0001). SRS scores 83% latest follow-up. One case distal adding-on 2 deep wound infections required additional surgery. No neurologic, pseudarthrosis or implant complications developed.

Conclusions:This is the largest (N=103), consecutive series of North American patients with AIS treated with pedicle screws having a minimum 3-year follow-up. The average curve correction was 68% (MT), 50% (PT), and 66% (TL/L) at FFU. We found excellent coronal/sagittal balance, curve correction and improved AVR at follow-up. There were no construct-related complications/decompensation, pseudarthrosis or neurologic deficits.