Sternum separation in the postoperative period: analysis of risk factors

This study aimed to assess the main risk factors contributing to postoperative separation of the sternum and to substantiate the recommendations on the optimal number of sternal polyspast and multi-twist knots based on data from international literature and our own experience. In this study, the indicators such as gender, age, height, body weight, body mass index, diabetes mellitus, chronic obstructive pulmonary disease, bronchial asthma, separation during the surgery of the internal thoracic artery, and re-exploration were evaluated. A key indicator was the sutures applied on the sternum after sternotomy, precisely the suture type (polyspast and multi-twist) and number. The study was conducted in the Federal Cardiovascular Surgery Center of the Ministry of Health of Russia (Chelyabinsk). The final sample was 1 051 patients in 2019. The patients were distributed into two groups; those without separation of the sternum in the postoperative period (n= 1 038) and those with sternum separation (n= 13). In the course of this study, we found that the most significant factors were the height and weight of patients. The multivariate analysis of variance showed that for multi-twist sutures, an additional sternal knot was required for every 4 cm of height, starting from 163 cm, and for every 7 kg of body weight, starting from 81 kg. For polyspast sutures, one additional sternal knot was required for every 5 cm of height, starting from 165 cm, as well as for every additional 5 kg of body weight, starting from 76 kg. When planning the number of sternal sutures, the height and weight of the patients body should be taken into account in aggregate, and the number of knots should be formed according to a more significant indicators.