Phrenic nerve repair, an experimental study

Abstract

In several of our patients the phrenic nerve has had to be resected during radical operations for malignant lung and mediastinal tumors. Phrenic nerve injury usually causes severe respiratory dysfunction. Repair of the injured phrenic nerve could prevent diaphragmatic dysfunction. We wished to confirm the possibility of phrenic nerve repair experimentally. Fourteen mongrel dogs were anesthetized, and the left thorax was opened. The left phrenic nerve was sectioned 3 cm above the diaphragm, and epi-perineurial repair was performed. Electromyograms of the diaphragm (EMG-di) were recorded from surface electrodes over the lower intercostal spaces. Compound muscle action potentials (M waves) were studied during supramaximal phrenic stimulation in the neck and thorax. Estimations of the activities of phrenic nerve and diaphragm were performed pre-and post-operatively and every 4 weeks until 12 weeks after the operation. We confirmed that the phrenic nerve and diaphragmatic activity were restored to normal by 8 weeks after surgery.