Invasive Procedures to the Neck and Chest and Hemidiaphragmatic Paralysis: Are They Always Causally Associated?

Three cases of hemidiaphragmatic paralysis are reported. One case was associated with an interscalene brachial plexus block, another with the insertion of an implantable cardioverter defibrillator, and a third case had undergone a coronary artery bypass grafting operation. In only one of these cases, there was a causal association, while in the other two, it was determined that the paralysis was coincidental. A change in the diaphragmatic position on the chest X-ray needs to be demonstrated, preferably also confirmed by ultrasound or a fluoroscopic sniff test, to show that the paralysis was a clear and immediate consequence of the procedure. One case described was most likely related to cervical nerve C3-C5 root compression confirmed on a magnetic resonance imaging (MRI) scan and not due to the procedure. This case shows that cervical root compression at C3-C5 by disk prolapse should also be considered. This was also suspected in another case; however, an MRI could not be performed after discussing the risks with the patient. When the paralysis has no temporal relationship with the procedure, primary or secondary intrathoracic malignancy and concurrent neurological disease must also be excluded by computed tomography of the thorax. The surgical and interventional causes of phrenic nerve injury and the relative evidence base are discussed.