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 poten tials (SSEPs). We studied 60 patients undergoing coronary bypass and intern al mammary harvest. Assessment of brachial plexus function was performed pr e- and postoperatively. Patients were assigned the use of a Pittman(TM) (MN Scientific Instruments Inc., Minneapolis, MN), Rultract(TM) (Rultract Inc. , Cleveland, OH),or Delacroix-Chevalier(TM) (Delacroix-Chevalier, Paris, Fr ance) asymmetric sternal retractor for internal mammary exposure. SSEP chan ges from baseline during asymmetric retractor use and removal were determin ed, and average changes were compared among the retractor groups. Patient d emographics and baseline SSEP values were similar. Fewer patients in the De lacroix-Chevalier(TM) group had decreases in SSEP amplitudes after retracto r placement. Of the patients in the Rultract(TM) and Pittman(TM) groups, 45 % and 25%, respectively, had amplitude decreases of >50%, compared with onl y 5% of the Delacroix-Chevalier(TM) patients. Three patients in both the Pi ttman(TM) and Rultract(TM) groups and one patient in the Delacroix-Chevalie r(TM) group suffered brachial plexus symptoms postoperatively. We conclude that the Delacroix-Chevalier(TM) retractor is associated with less neurophy siologic evidence of brachial plexus dysfunction during asymmetric sternal retraction compared with either the Pittman(TM) or Rultract(TM) sternal ret ractors. Implications: We used somatosensory evoked potentials to assess th e effect of several different asymmetric sternal retractors on brachial ple xus dysfunction and to determine which produced the least evidence of nerve damage during surgical exposure of the internal mammary artery.