2014 Neer Award Paper: Neuromonitoring the Latarjet procedure Ruth A. Delaney, MB BCh, BAO, MRCS a , Michael T. Freehill, MD a , David R. Janfaza, MD b , Kamen V. Vlassakov, MD b , Laurence D. Higgins, MD c , Jon J.P. Warner, MD a, * a Boston Shoulder Institute, Massachusetts General Hospital, Boston, MA, USA b Department of Anesthesiology, Brigham & Women’s Hospital, Boston, MA, USA c Boston Shoulder Institute, Brigham & Women’s Hospital, Boston, MA, USA Background: We used intraoperative neuromonitoring to define the stages of the Latarjet procedure during which the nerves are at greatest risk. Methods: Thirty-four patients with a mean age of 28.4 years were included. The Latarjet procedure was divided into 9 defined stages. Bilateral median and ulnar somatosensory evoked responses and transcranial motor evoked potentials from all arm myotomes were continuously monitored. A ‘‘nerve alert’’ was defined as averaged 50% amplitude attenuation or 10% latency prolongation of ipsilateral somatosensory evoked responses and transcranial motor evoked potentials. For each nerve alert, the surgeon altered retractor placement, and if there was no response to this, the position of the operative extremity was then changed. Results: Of 34 patients, 26 (76.5%) had 45 separate nerve alert episodes. The most common stages of the procedure for a nerve alert to occur were glenoid exposure and graft insertion. The axillary nerve was involved in 35 alerts; the musculocutaneous nerve, in 22. Of the 34 patients, 7 (20.6%) had a clinically detectable nerve deficit postoperatively, all correlated with an intraoperative nerve alert. All cases involved the axillary nerve, and all resolved completely from 28 to 165 days postoperatively. Prior surgery and body mass index were not predictive of a neurologic deficit postoperatively. However, total operative time (P ¼ .042) and duration of the stage of the procedure in which the concordant nerve alert occurred (P ¼ .010) were statistically significant predictors of a postoperative nerve deficit. Conclusions: The nerves, in particular the axillary and musculocutaneous nerves, are at risk during the Latarjet procedure, especially during glenoid exposure and graft insertion. Level of evidence: Level IV, Case Series, Treatment Study. Ó 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Keywords: Instability; Latarjet procedure; neurologic complications; axillary nerve; musculocutaneous nerve The Latarjet procedure is a proven, established method of treating glenohumeral instability, particularly when there is bone loss of the glenoid or after a failed soft tissue instability repair. One large series reported a 5% redis- location rate and 96% patient satisfaction. 5 Other large series have reported more than 1000 procedures with an Partners Healthcare Institutional Review Board approval: Protocol # 2011P000188. *Reprint requests: Jon J.P. Warner, MD, The Harvard Shoulder Service, 55 Fruit St, Yawkey Center for Outpatient Care, Suite 3200, 3G, Room 3- 046, Boston, MA 02114, USA. E-mail address: jwarner@partners.org (J.J.P. Warner). J Shoulder Elbow Surg (2014) 23, 1473-1480 www.elsevier.com/locate/ymse 1058-2746/$ - see front matter Ó 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. http://dx.doi.org/10.1016/j.jse.2014.04.003