Ultrasound Guided Phrenic Nerve Block for Percutaneous Computer Tomography Guided Lung Biopsy

Abstract

Abstract The aim of this paper is to present the technique of the ultrasound (US) guided phrenic nerve block (PNB). This is an important adjuvant technique for percutaneous computer-tomography (CT) lung biopsy of nodules situated in the lower lobes, in proximity of the diaphragm, with a diameter of less than 2 cm. These types of nodules have a high location variability during respiration, which makes them hard to be approached for a successful biopsy. US visualization of the nerve is possible after identifying specific landmarks as the sternocleidomastoid and scalene muscle, interval jugular vein and brachial plexus. The phrenic nerve is seen as an oval hypoechogenic structure with no Doppler signal, superficial to the anterior scalene muscle. Ropivacaine can be used as a local anesthetic to induce the PNB. Results: Success of the phrenic nerve block can be assessed by CT scanogram, which shows the ipsilateral hemidiaphragm elevated, and by subsequent lung scans that show little to no location variability of the target lesion. Conclusion. US-guided PNB is a safe and efficient procedure that can help during percutaneous CT-guided lung biopsy of small basal nodules.