Pedicle screw dimension in young patients at the national orthopaedic hospital Dala Kano Nigeria

Background: Paediatric spine surgery requires meticulous preoperative planning to select appropriate pedicle screw dimensions, as the immature spine presents unique anatomical challenges. This study aimed to determine the pedicle screw sizes and lengths used in young patients at a Nigerian tertiary hospital and evaluate the influence of preoperative CT-based planning on outcomes. Methods: A retrospective review of 97 patients aged 6 to <18 years who underwent pedicle screw instrumentation at the National Orthopaedic Hospital Dala, Kano, from January 2019 to December 2025 was conducted. Indications included spinal infection (n=68, 70.1%), trauma (n=21, 21.6%) and scoliosis (n=8, 8.2%). Preoperative CT was used to measure pedicle transverse diameter, pedicle length and vertebral body dimensions to guide screw selection. Outcomes assessed included screw accuracy using the Gertzbein-Robbins classification, complications and need for revision. Results: A total of 339 pedicle screws were inserted (mean 3.5 screws per patient). Screw diameters ranged from 4.0 mm to 6.5 mm, with 5.0 mm (42.5%) and 5.5 mm (31.0%) being most common. Screw lengths ranged from 25 mm to 45 mm, with 30 mm (34.8%) and 35 mm (29.5%) being most frequent. Preoperative CT measurements demonstrated that pedicle transverse diameter increased with age (r=0.52, p<0.001). Screw accuracy (Gertzbein-Robbins grades A and B) was achieved in 92.6% of screws. Complications occurred in 8 patients (8.2%), including 3 (3.1%) with screw malposition requiring revision. Factors influencing screw dimension included age, level of instrumentation and underlying diagnosis. Conclusions: Preoperative CT-based planning facilitates appropriate pedicle screw selection in paediatric patients. Screw diameters of 5.0–5.5 mm and lengths of 30–35 mm were most frequently used in this Nigerian cohort. Age and spinal level are important determinants of screw dimension.