From the Guidelines
To avoid phrenic nerve injury during mitral valve replacement, surgeons should exercise visual observation and attention to individual anatomical differences to avoid excessive tension on the right phrenic nerve, as emphasized in the study by 1. When performing mitral valve replacement, it is crucial to be mindful of the phrenic nerve's location and take preventive measures to avoid injury. The study by 1 highlights the importance of gentle caudal retraction of the diaphragm using a figure-of-eight suture or pledgeted horizontal mattress suture, allowing for complete direct visualization of the surgical field without putting excessive tension on the right phrenic nerve. Some key considerations for avoiding phrenic nerve injury include:
- Visual confirmation that the right side of the heart is empty and there is no cardiac ejection before opening the pericardium
- Placing stay sutures at the superior portion of the dome of the diaphragm to allow for gentle caudal retraction
- Avoiding excessive tension on the right phrenic nerve during retraction or manipulation of the pericardium
- Using a separate entry in the same intercostal space as the working port for the atrial retractor post to minimize the risk of injury to the internal mammary artery and phrenic nerve By following these guidelines and prioritizing meticulous surgical technique, surgeons can minimize the risk of phrenic nerve injury and optimize patient outcomes in terms of morbidity, mortality, and quality of life, as supported by the study by 1.
From the Research
Avoiding Phrenic Nerve Injury during Mitral Valve Replacement
To avoid phrenic nerve injury during mitral valve replacement, several strategies can be employed:
- Minimizing the use of cold-induced injury during myocardial protection strategies, as this has been shown to be a cause of phrenic nerve injury 2
- Avoiding mechanical injury during internal mammary artery harvesting, as this can also cause phrenic nerve injury 2
- Using electrophysiological evaluation to monitor phrenic nerve function before and after surgery, allowing for early detection of any injury 3
- Modifying surgical techniques to avoid areas where the phrenic nerve is likely to be located, such as the carina and anterior right superior and inferior pulmonary veins 4
- Avoiding the use of ice-slush around the heart, as this has been shown to contribute to phrenic nerve injury 3
Surgical Techniques
Surgical techniques that can help avoid phrenic nerve injury include:
- Using a beating heart approach for coronary artery bypass grafting (CABG), which eliminates the need for cardiopulmonary bypass (CPB) and hypothermia 3
- Performing mitral valve replacement without the use of CPB and hypothermia, if possible
- Using a minimally invasive approach, which may reduce the risk of phrenic nerve injury 5
Monitoring and Treatment
Monitoring phrenic nerve function before and after surgery can help detect any injury early, allowing for prompt treatment: