Does pedicle screw fixation under age 5 cause spinal canal narrowing? A CT study with minimum 5 years follow-up

Abstract

The aim of this retrospective study was to evaluate the changes in the vertebral body and spinal canal area in a group of patients who had pedicle screw fixation under age 5 for the treatment of congenital spinal deformity at least 5 year follow-up. 11 patients who had been operated due to spinal deformity under age 5 with who had a CT examination at least 5 years after the initial operation were included in the study. All patients underwent hemivertebrectomy and transpedicular fixation procedures at an average age of 3.18 years (range 2-5 years). All had preoperative CT to evaluate the congenital deformities. Measurements were done at the instrumented vertebrae as well as the un-instrumented ones above and below them to evaluate; vertebral body parameters, pedicle parameters and spinal canal area of upper instrumented vertebra (UIV), lower instrumented vertebra (LIV), upper adjacent un-instrumented vertebra and lower adjacent un-instrumented vertebra. The average follow-up was 7.2 (range 5-12) years. Six of the patients were over age 10 during the final CT examination while 5 were at age 7. Female-to male ratio was 8-3. Measurement of all the parameters in 22 instrumented and 22 non-instrumented segments showed a proportional increase rather than a decrease at each segment. The percentage of canal area growth at UIV and LIV was 21 and 17.5 %, respectively. Pedicle screw instrumentation has no adverse effect on further spinal body, pedicle and canal growth and does not result in iatrogenic spinal canal stenosis.