Cardiac injury at the time of reoperation after a previous sternotomy is considered an unfortunate but inevitable complication which any surgeon dealing with thoracic or cardiac surgery could be faced with.2
The risk of catastrophic haemorrhage on sternal re-entry is estimated to be 0.5–1% with an associated mortality rate of 21%,3
and increases in patients with a history of mediastinitis, sternal wound infection and enlarged heart.4
The major cause of complications in such cases are adhesions between the posterior lamina of the sternum and the innominate vein, right ventricle, and sometimes also the extracardiac conduits and grafts.2,3
Since preparing the tunnel for the gastric tube behind the sternum is primarily a blind procedure, it carries an increased risk of injury to these structures. For that very reason a key factor before re-entering the retrosternal space is the careful diagnosis and anticipation of potential problems.
Therefore, the condition of the retrosternal adhesion should be routinely checked preoperatively. It is essential for the surgeon to become acquainted with the protocol of the previous intervention, as the conduct of the first operation sets up the morbidity of the second. Generally, the risk of haemorrhage should diminish if the pericardium was closed at the first operation. In our case, however, according to the protocol the pericardium was sutured after the mitral valve replacement. Thus, the actual state of the retrosternal space should also be assessed objectively and the surgeon should check a preoperative computed tomography (CT) scan in order to evaluate the distension of the right atrium or right ventricle, the position and size of the great vessels, and also the amount of space between the sternum and the heart or any patent grafts.2
Nonetheless, even if the heart is very close to the sternum, CT scans can indicate whether or not there is any fatty tissue between the heart and the sternum. If fatty tissue is present, there is less risk of haemorrhage with re-entry.5
However, the situation becomes even more complicated if the patient has had previous coronary artery bypass surgery. In that case, a CT scan is not sufficient to assess the risk of the bypass injury. At this juncture the patient should have the preoperative repeat catheterisation of the coronary vessels. Lack of movement of coronary artery grafts on the catheterisation films should raise the suspicion of a graft that is adherent to the sternum.2
Ultimately, if the estimated risk of blind tunneling is high, the surgeon should consider passing the gastric tube not via the retrosternal route, as in this case, but in the anatomical position of the oesophagus. This can be achieved by conventional open surgery, but also, if possible, using alternative surgical techniques such as thoracoscopic oesophageal dissection. This avoids the risk associated with the retrosternal adhesions, but also had its drawbacks.
Anterior mediastinal reconstruction helps in the prevention of tumour recurrence within the gastric conduit6,7
or permits avoidance of conduit irradiation if postoperative radiation therapy is needed for residual disease. Other possible advantages of anterior reconstruction include ease and efficiency of further interventions such as drainage for anastomotic leakage, reoperation for anastomotic strictures, or percutaneous endoscopic gastrostomy.8,9
In conclusion, we suggest that the patient who has undergone previous cardiac surgery and requires oesophageal resection needs not only routine preoperative assessment, but also a careful estimation of the retrosternal region.
- Cardiac injury at the time of reoperation could be faced by all surgeons operating in the retrosternal space.
- The pivotal factor before re-entering this space is the careful diagnosis and anticipation of potential problems.
- The condition of the retrosternal adhesion should be routinely checked preoperatively.
- The scheduled operating plan should always take into account the adhesion in the retrosternal space.