Temporal Evolution of Sternal Healing on Chest CT Following Median Sternotomy: A Retrospective Analysis of Patterns of Fat Stranding, Lymphadenopathy, and Callus Formation.

Abstract

Objective: Outline the expected course of normal sternal healing at different timepoints after surgery.

Materials and methods: A total of 270 chest CT examinations in 228 unique patients performed between January 2018 and 2022 were retrospectively identified in patients who had undergone a first-time median sternotomy for elective surgery within the preceding 18 months. These examinations were divided into 4 intervals based on time since surgery-0 to 2 months, 2 to 6 months, 6 to 12 months, and >12 months. Basic patient data, surgery type, and imaging findings and measurements for the sternum and mediastinum were characterized and summarized.

Results: Osseous callus was initially rare (manubrium 5.1%, sternal body 7.8% to 8.7%) but increased over time, reaching 87.2% in the manubrium and 78.7% to 85.1% in the sternal body beyond 12 months, with consistently lower prevalence in the manubrium at intermediate timepoints. The sternal gap measurements were widest at 2 to 6 months and smallest at 0 to 2 months and >12 months. Pneumomediastinum was exclusively seen at 0 to 2 months (36.2% of examinations). Mediastinal fat stranding (95.7%) and lymphadenopathy (23.3%) were most common at 0 to 2 months and persisted in a minority of patients at later timepoints.

Conclusions: Post-sternotomy healing is prolonged and variable, with the manubrium demonstrating slower callus formation and persistently wider sternal gaps than the sternal body. Early postoperative findings such as mediastinal fat stranding, lymphadenopathy, and osseous resorptive changes are common and may reflect normal healing rather than pathology, with callus typically evident after 6 months.