Do Age or Gender Influence Sternal Instability and Deep Sternal Wound Healing Disorders after Median Sternotomy?

Background: The aim of the study was to examine age and sex differences regarding the development of deep sternal wound infections and sternal instability after median sternotomy.

Method: We performed a propensity score matching analysis with 4,505 patients who underwent cardiac surgery from 2009 to 2021 at our department. All patients had a BMI of ≥ 30 kg/m². We determined 1,297 matched pairs in the sex group (age, logistic EuroSCORE, BMI) and 1,449 matched pairs in the age-related group (sex, logistic EuroSCORE, BMI). The distributions of sex, age, diabetes mellitus, delirium, unstable sterna, wire refixation, wire removal, superficial and deep vacuum-assisted wound closure, clamp time, bypass time, logistic EuroSCORE, and BMI were assessed.

Results: Thirty-day in-hospital mortality was the same in patients >80 years and ≤80 years of age (8.149 vs. 8.35%, p = 0.947). Diabetes mellitus was also equally distributed in both groups. Postoperative delirium occurred significantly more often in the older group (29.81 vs. 17.46%, p < 0.001). Sternum instability (3.86 vs. 4.62%, p = 0.357) occurred equally often. Deep and superficial vacuum-assisted wound closures were also equally distributed in both groups (3.59 vs. 2.69%, p = 0.201 and 5.87 vs. 5.52%, p = 0.758, respectively).

Equal numbers of men and women died within 30 days after surgery (8.07 vs. 8.17%, p = 0.943). Regarding postoperative delirium, there was a significantly higher incidence in men compared with women (16.96 vs. 26.91%, p < 0.001). Regarding unstable sternum (3.32 vs. 4.47%, p = 0.155), superficial (5.55 vs. 5.09%, p = 0.662), and deep (2.54 vs. 3.01%, p = 0.55) vacuum-assisted wound closure there were no differences between men and women.

Conclusion: Sternal instability and deep wound healing problems occur with equal frequency in ≤80s and >80s and in men and women undergoing median sternotomy. This is contrary to our assumption that the quality of the sternum is better in male patients than in postmenopausal women and should have led to more stable rewiring. However, delirium was observed significantly more often in older male patients. It can be speculated that the hypermobility and reduction or absence of protective reflexes during delirium play a role in the development of sternal instability and deep sternal wound healing disorders beyond the load-stable tension band osteosynthesis, thus negating the hypothesized advantage of stability of the rewired male sternum.