Symptoms of Sternal Nonunion Late after Cardiac Surgery

Background  A cohort of patients having symptoms of sternal nonunion late after sternotomy was studied to find out whether the complaints were related to true sternal nonunion or decreased bone density. Methods  A survey was mailed to 2,053 cardiac surgical patients operated in our institution between July 2007 and June 2010. The patients were requested about symptoms referring to sternal instability. A group of symptomatic individuals as well as 1:1 age- and time-matched asymptomatic controls were examined with sternal palpation, ultrasound during standardized sternal pressure provocation, and computed tomography (CT). Results  The number of patients replied in the survey was 1,918 (93.4%); 2.3% (44 patients) reported sensation of movement or clicking in sternum during body movements and during coughing. Symptomatic patients living within 200 km to the hospital (21) and their asymptomatic controls (21) were selected for further clinical and imaging studies. Mean period between the initial operation and the examinations was 36 (22–56) months. Sternal palpation pain was significantly associated with reported symptoms suggestive of sternal nonunion (odds ratio [OR] 22.0; 95% confidence interval [CI] 2.5–195); however, none of the patients had clinically unstable sternum or nonunion in the sternal imaging. The symptoms of sternal instability were more frequent in patients whose bone mineralization rate (as measured with T-scores) was higher. Conclusion  Symptoms suggestive of sternal nonunion were experienced by 2.3%. However, their symptoms did not correlate with CT scans or provocation ultrasound although palpation pain was evident. Thus the pain is derived from nonmechanical etiologies. Higher bone mineralization rate correlated with abnormal symptoms of sternal wound.