Incidence of peripheral nerve injury during shoulder arthroplasty when motor evoked potentials are monitored

Alexander W. Aleem, W. Bryan Wilent, Alexa C. Narzikul, Andrew F. Kuntz, Edward S. Chang, Gerald R. Williams, Joseph A. Abboud

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


To report the incidence of clinically detectable nerve injuries when utilizing transcranial electrical motor evoked potentials (MEPs) during shoulder arthroplasty. A retrospective review of patients undergoing shoulder arthroplasty with continuous IONM was performed. The criteria for nerve alerts was an 80% amplitude reduction in MEPs. The primary outcome measure was post-operative clinically detectable nerve deficit. An additional retrospective analysis on a subset of cases using an all-or-none (100% amplitude reduction) criterion applied to the deltoid was performed. Two hundred eighty four arthroplasty cases were included. There were no permanent post-operative nerve injuries and two transient nerve injuries (0.7%). MEP alerts occurred in 102 cases (36.2%). Nineteen (6.7%) cases did not have signals return above alert threshold at closure. These cases were significantly associated with post-operative nerve injury (p = 0.03). There were no false negatives, making sensitivity 100% and specificity was 93.9%. In the subset of cases in which an all-or-none criterion was retrospectively applied to just the deltoid, MEP alerts occurred in just 17.9% of cases; specificity improved to 98.0%. We conclude that utilization of the real-time diagnostic MEP data during shoulder arthroplasty aids surgeons in decision making regarding impending peripheral nerve injuries.

Original languageEnglish
Pages (from-to)897-906
Number of pages10
JournalJournal of Clinical Monitoring and Computing
Issue number5
StatePublished - Oct 1 2018


  • Intraoperative motor evoked potentials
  • Nerve injury
  • Peripheral nerve function
  • Peripheral nerve monitoring
  • Shoulder arthroplasty


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