Discussion
Re-sternotomy is more challenging than primary sternotomy because of adhesions8-10 and patients’ poor health status. Increased reoperation risk through the reconstructed sternum is reported due to the small amount of tissue initially placed over the mediastinum8. Few reports described re-sternotomy after an omental flap procedure5, although there have been some similar reports6, 7. In our case, severe adhesion between the omentum and mediastinal organs was expected because preoperative CT showed limited space between the sternum and omentum due to funnel chest. Re-sternotomy was completed safely because partial cardiopulmonary bypass was introduced by decompression of the cardiac volume and the omentum functioned as a cushioning material between the sternum and mediastinal organs.
Although no reports have described this effect, the omentum tissue can serve as a safety net for the mediastinal organs to prevent from injury. Adachi et al. reported re-sternotomy after omental flap in which dissection was safely performed5. Among 15 pediatric cardiac patients who underwent treatment for mediastinitis, 3 (2 with rectus flaps and 1 with pectoralis flap) underwent re-sternotomy6. The surgeries were uneventful because the rectus abdominus muscle was mobilized and removed6. According to Varennes et al, re-sternotomy after muscle flap repair could likely be accomplished without risk and heart transplantation could be carried out7. On the other hand, repeat median sternotomy after an omental flap procedure is more hazardous because of severe adhesions between the omentum and mediastinal structures11. Further studies regarding this feature of the omental flap are warranted.
Diversity of ultrasonic devices available may cause more efficient surgical procedures and improved patient outcomes12. The ultrasonic scalpel is excellent in exfoliating adipose tissue. In our patient, an ultrasonic scalpel was useful for dissecting between the omentum and mediastinal organs, especially above the ascending aorta. Adachi et al. also reported the effectiveness of an ultrasonic scalpel for dissection during this procedure5. Because Adachi’s patient received ascending aortic and aortic valve replacement and mitral valve repair, the omental tissue was mobilized to the left side of the anterior mediastinum5, whereas in our patient, it was mobilized to the right side due to planned bypass grafting to the obtuse marginal branch.
Although it might be difficult to detect targeted coronary arteries after surgical treatment for mediastinitis because of severe adhesion9, 10, the coronary arteries were detected easily in our patient. According to Roselli et al, most injuries including heart chambers, great vessels and native coronary artery occurred on opening and during prebypass dissection10. In the present case, inflammation due to mediastinitis might have been limited to the area around the sternum and might not have extended into the pericardial cavity.