Electronic Thesis and Dissertation Repository


Master of Science




Murkin, John

2nd Supervisor

Bainbridge, Daniel


3rd Supervisor

Chui, Jason



INTRODUCTION: The high incidence of peripheral nerve injury (PNI) in conventional cardiac surgery (CCS) is believed to result from mechanical injury during sternotomy and/or retraction of the sternum. Minimally invasive cardiac surgery (MICS) is a newly developed type of cardiac surgery which does not require sternotomy or retraction of the sternum. Since surgery related PNI can lead to serious problems for both the patients and care providers, the incidence and details of PNI in cardiac surgery needs to be investigated. OBJECTIVE: To compare the degree of nerve injury in MICS and CCS using somatosensory evoked potential (SSEP) signals. METHODS: 51 participants were prospectively observed during surgery for abnormal SSEP signals. SSEP signals were obtained using EPAD®. Also, all participants were assessed pre and postoperatively for neurological symptoms involving bilateral upper limbs. RESULTS: The primary outcome was obtained from 41 participants. There was a significant difference (P=0.031) in abnormal SSEP signals between the CCS (n=22) and MICS (n=19) groups. The nerve injury was greater in CCS group compared to MICS group. Abnormal SSEP signals were observed independently of sternotomy or sternal retraction. CONCLUSIONS: This study suggests that CCS is associated with more intraoperative nerve injury when compared with MICS.