Sternal instability measured with radiostereometric analysis. A study of method feasibility, accuracy and precision

• Published in: Journal of cardiothoracic surgery Vol. 13; no. 1; p. 41
• Main Authors: Vestergaard, Rikke Falsig, Søballe, Kjeld, Hasenkam, John Michael, Stilling, Maiken
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 18.05.2018; BioMed Central; BMC
• Subjects: Bone healing; CAT scans; Methods; Radiology; Sternum; Wound healing; Sternum; Wound healing; Bone healing
• ISSN: 1749-8090; 1749-8090
• DOI: 10.1186/s13019-018-0735-4

A small, but unstable, saw-gap may hinder bone-bridging and induce development of painful sternal dehiscence. We propose the use of Radiostereometric Analysis (RSA) for evaluation of sternal instability and present a method validation. Four bone analogs (phantoms) were sternotomized and tantalum beads were inserted in each half. The models were reunited with wire cerclage and placed in a radiolucent separation device. Stereoradiographs (n = 48) of the phantoms in 3 positions were recorded at 4 imposed separation points. The accuracy and precision was compared statistically and presented as translations along the 3 orthogonal axes. 7 sternotomized patients were evaluated for clinical RSA precision by double-examination stereoradiographs (n = 28). In the phantom study, we found no systematic error (p > 0.3) between the three phantom positions, and precision for evaluation of sternal separation was 0.02 mm. Phantom accuracy was mean 0.13 mm (SD 0.25). In the clinical study, we found a detection limit of 0.42 mm for sternal separation and of 2 mm for anterior-posterior dislocation of the sternal halves for the individual patient. RSA is a precise and low-dose image modality feasible for clinical evaluation of sternal stability in research. ClinicalTrials.gov Identifier: NCT02738437 , retrospectively registered.