Teaching Case

A 78-year-old woman was admitted to the emergency department due to sudden and severe shortness of breath. Her medical history included arterial hypertension and coronary artery bypass graft (CABG).

A conventional radiograph of the chest revealed elevation of the right hemi-diaphragm and sternal diastasis due to wire-breaking (Fig. a), without obvious consolidation.
To rule out lung embolism, a contrast-enhanced CT of the chest was performed. This revealed bilateral consolidations and adjacent pleural effusion; however, no lung emboli were seen. Additionally, there was a discontinuity of the abdominal wall immediately under the xiphoid process, with associated herniation of a large part of the left liver lobe (asterisk) and small bowel (arrow) into the subcutaneous fat (Fig. b,c).

Subxiphoid incisional herniation (SIH) is a rare complication after median sternotomy or subxiphoid trocar insertion.
The reported incidence of SIH after CABG is 0.8-4% [1], although this is probably an understatement because most SIH’s are asymptomatic and never diagnosed.
SIH develops usually within 2 to 3 years after surgery [1], due to diastasis of the suture. This is believed to result from lateral traction exercised on the suture by the abdominal muscles during breathing and coughing. Risk factors for the development of a subxiphoid hernia include: post-operative infection, female sex and BMI>30. [1, 2]
As mentioned above, most SIH are small and asymptomatic and are therefore never diagnosed. Larger herniations present as a painless, subxiphoid swelling. Strangulation of hernia contents is rare.
The diagnosis of SIH can be made clinically, given the typical location of the swelling and medical history of the patient. Ultrasound can confirm this diagnosis and visualise hernia contents.
The preferred examination is however computed tomography, as this does not only allow to visualise the contents of the SIH but also the extent of the lesion.
Recognition and correct diagnosis of this (sometimes impressive) image is essential to avoid unnecessary examinations and treatment.
In asymptomatic patients, a conservative approach is warranted.
If clinical symptoms are present, treatment is aimed at restoring the continuity of the abdominal wall by placing a prosthetic mesh over the defect. This can be performed either by open surgery or by a laparoscopic approach. [3]