RESEARCH ARTICLE


Evaluation of Sternal Bone Healing with Computed Tomography and a Quantitative Scoring Algorithm



Gregory S. Stacya, *, Osmanuddin Ahmeda, Arlene Richardsona, Brian M. Hatcherb, Heber MacMahona, Jaishankar Ramanc
a Department of Radiology, University of Chicago Medical Center, Chicago, IL
b Director of Research, Biomet Microfixation, Jacksonville, FL
c Department of Cardiothoracic and Vascular Surgery, Rush University Medical Center, Chicago, IL


© 2014 Stacy et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Department of Radiology, University of Chicago, 5841 S. Maryland Ave., MC 2026, Chicago, IL 60637-1470; Tel: 773-834-3046; Email: sstacy@radiology.bsd.uchicago.edu


Abstract

Objective:

The exquisite bone detail offered by computed tomography makes it the ideal modality for evaluation of bone healing. However, few studies have investigated the normal computed tomographic appearance of the sternum after median sternotomy and, to the best of our knowledge, no computed tomographic classification of sternal healing has been proposed. Given the potential benefit of objective criteria, we propose a validated scoring classification of sternal healing using computed tomography for both clinical and investigational purposes.

Methods:

Computed tomography scans from 20 patients who underwent a median sternotomy were evaluated for sternal healing at either 3 or 6 months postoperatively. Five anatomic locations along the sternum were selected using defined criteria, and a 6-point quantitative scale was developed to evaluate sternal healing. Independent radiologists read and scored each of the 5 locations on the sternum. Inter- and intra-observer variability was assessed by calculating the kappa statistics to measure the reliability of the scoring algorithm.

Results:

Calculation of the kappa statistics indicated substantial agreement for intra-observer variability and substantial to almost perfect agreement for inter-observer variability. For intra-observer variability, the kappa statistics ranged from 0.591 to 0.802, and for inter-observer variability, the kappa statistics ranged from 0.590 to 0.969. When the two radiologists differed, the magnitude of the difference was no more than 1 or 2 points.

Conclusion:

This simple system of evaluating sternal healing had high inter- and intra-observer reliability. Therefore, it may be considered a valid method for assessing sternal osteosynthesis for both clinical and investigative purposes.

Ultramini abstract: (49 words):

Few studies have investigated the normal computed tomography appearance of the sternum after median sternotomy, and we knew of no computed tomography-based classification of sternal healing. Given the potential benefit of objective criteria, we designed and validated a scoring classification of sternal osteosynthesis for both clinical and investigational purposes.

Keywords: Computed tomography, sternum, wound closure, wound dehiscence, wound healing.