Corresponding Author

Mohamed K Elkazaz

Subject Area

Deformity, Pediatrics

Document Type

Original Study


Background Data: Various methods to help guidance of screw purchase in AIS have been described in the literature. Free-hand technique is a relatively easy and is as accurate as other methods. MSCT scan, the most accurate method of postoperative evaluation of screw purchase still needs more research. Purpose: The aim of this study is to evaluate the accuracy and safety of the pedicle screw fixation (PSF) with free-hand technique in AIS using postoperative MSCT scan. Study Design: Prospective clinical case study. Patients and Methods: In this prospectively study all patients with AIS underwent correction using the free-hand PSF were reported. All patients underwent whole spine X-ray and MSCT scan during the follow up. Screw purchases were evaluated according to Gertzbein Robbin classification. Results: A total of 45 patients were recruited for this study with mean age 14.7±1.7 including 39 females and 6 males. Of the total 870 pedicle screws, 85.1% (740) screws were accurate within the pedicle, while 14.9% (130) screws penetrated the pedicle including medial wall penetration in (5.9%) and lateral penetration in (9.0%). Overall, 18.3% of thoracic screws penetrated the pedicle while 5.9% of lumbar screws penetrated the pedicle. Correlation of screw purchase accuracy to age, sex, curve type, Cobb angle, spinal region showed no statistically significant correlation. Conclusions: The data of this prospective study suggest that pedicle screw fixation with free-hand technique in adolescent idiopathic scoliosis population appears to be an accurate and safe procedure. (2022ESJ263)


free-hand technique, adolescent idiopathic scoliosis, pedicle screw fixation, pedicle screw accuracy, postoperative CT scan