Somatosensory Evoked Potential Monitoring Used to Compare the Effect of Three Asymmetric Sternal Retractors on Brachial Plexus Function

We compared the effect of three different asymmetric sternal retractors on brachial plexus dysfunction using intraoperative somatosensory evoked potentials (SSEPs).We studied 60 patients undergoing coronary bypass and internal mammary harvest. Assessment of brachial plexus function was performed pre- and postoperatively. Patients were assigned the use of a Pittman[trade mark sign] (MN Scientific Instruments Inc., Minneapolis, MN), Rultract[trade mark sign] (Rultract Inc., Cleveland, OH), or Delacroix-Chevalier[trade mark sign] (Delacroix-Chevalier, Paris, France) asymmetric sternal retractor for internal mammary exposure. SSEP changes from baseline during asymmetric retractor use and removal were determined, and average changes were compared among the retractor groups. Patient demographics and baseline SSEP values were similar. Fewer patients in the Delacroix-Chevalier[trade mark sign] group had decreases in SSEP amplitudes after retractor placement. Of the patients in the Rultract[trade mark sign] and Pittman[trade mark sign] groups, 45% and 25%, respectively, had amplitude decreases of >50%, compared with only 5% of the Delacroix-Chevalier[trade mark sign] patients. Three patients in both the Pittman[trade mark sign] and Rultract[trade mark sign] groups and one patient in the Delacroix-Chevalier[trade mark sign] group suffered brachial plexus symptoms postoperatively. We conclude that the Delacroix-Chevalier[trade mark sign] retractor is associated with less neurophysiologic evidence of brachial plexus dysfunction during asymmetric sternal retraction compared with either the Pittman[trade mark sign] or Rultract[trade mark sign] sternal retractors. Implications: We used somatosensory evoked potentials to assess the effect of several different asymmetric sternal retractors on brachial plexus dysfunction and to determine which produced the least evidence of nerve damage during surgical exposure of the internal mammary artery. (Anesth Analg 1999;88:292-7)