Microdose protocol stereoradiography has similar reliability to standard low-dose protocol during concurrent Sanders skeletal maturity staging.

Abstract

Decreasing radiation exposure is important for scoliosis patients who require serial imaging. Microdose protocol stereoradiography is now increasingly utilized. Previous studies have reported similar reliability of concurrent Sanders skeletal maturity staging based on standard low-dose stereoradiography and standard hand radiographs. The purpose of our study was to investigate the reliability and radiation exposure of concurrent Sanders staging using microdose protocol compared to a standard protocol for adolescent idiopathic scoliosis. We hypothesized that surgeon-performed Sanders staging would have similar reliability when comparing microdose and standard-dose imaging protocols. A randomized survey of 30 hand images using standard protocol spinal stereoradiography and an equal number from microdose protocol were distributed to six experienced pediatric orthopaedic spine surgeons. Images were graded by each surgeon according to the Sanders skeletal maturity grading system. Items were again randomized and graded after a 2-week interval. Fleiss' weighted kappa for inter and intraobserver reliability was calculated and an unpaired t test was used to test for significance. Interobserver reliability for all modalities was in the strong to almost perfect agreement (average weighted κ > 0.8) range. For the microdose protocol, κ was 0.82 and 0.84 for each separate round of grading. Standard low-dose protocol κ was 0.83 and 0.79. Intraobserver κ was 0.86 for microdose and 0.82 for standard. Average radiation for microdose was significantly less radiation (82.6%) than standard stereoradiography (0.3 ± 0.1mGy vs. 1.9 ± 0.4mGy, p < 0.001). Sanders staging reliability of a well-positioned hand during scoliosis stereoradiography was similarly excellent for both microdose and standard low-dose protocol. Microdose protocol used less radiation while still preserving the reliability of Sanders staging.