Case report: cardiac herniation following robotic-assisted thymectomy

The first reported case of cardiac herniation was in 1948 and occurred following pericardiectomy during a lung cancer resection. Although rare, this potentially fatal surgical complication may occur following any operation in which a pericardial incision or resection is performed. The majority of literature on cardiac herniation involves case reports after intrapericardial pneumonectomy. Currently, there are no reports of cardiac herniation after thymectomy with pericardial resection.

A 44-year-old Asian female with symptomatic myasthenia gravis was referred for thymectomy. Originally thought to have Bell's Palsy, her symptoms began with right eyelid drooping and facial weakness. Over time, she developed difficulty holding her head up, upper extremity weakness, difficulty chewing and dysarthria. These symptoms worsened with activity. She was found to have positive acetylcholine receptor binding antibody on her myasthenia gravis panel. A preoperative CT scan demonstrated a 3.5 cm × 2 cm anterior mediastinal mass along the right heart border and phrenic nerve. A complete thymectomy, via right-sided robotic-assisted approach was performed en bloc with a portion of the right phrenic nerve and a 4 cm × 4 cm portion of pericardium overlying the right atrium and superior right ventricle. Upon undocking of the robot and closure of the port sites, the patient became acutely hypotensive (lowest recorded blood pressure 43/31 mmHg). The camera was reinserted and demonstrated partial cardiac herniation through the anterior pericardial defect toward the right chest. An emergent midline sternotomy was performed and the heart was manually reduced. The patient's hemodynamics stabilized. A vented Gore-Tex 6 cm × 6 cm patch was sewn along the pericardial edges with interrupted 4-0 prolene to close the pericardial defect.

This potentially fatal complication, although rare, should always be considered whenever there is hemodynamic instability entry or resection of the pericardium during surgery. We now routinely sew in a pericardial patch using our robotic surgical system for any defect over 3 cm × 3 cm that extends from the mid- to inferior portions of the heart.