In a study performed by the Harvard Shoulder Service, it has been documented that there is a significant incidence of neurologic complications of the Latarjet procedure for shoulder instability. 5 out of 52 patients had neurologic complaints post-operatively. 3 of these nerve palsies were transient, however 2 had not yet recovered fully at time of latest follow-up and returned to the operating room for exploration and neurolysis of the axillary nerve and brachial plexus.

By using intra-operative neuromonitoring to determine exactly when there is a potential nerve injury during the procedure, the investigators will be able to modify what the investigators do at that step of the procedure, in order to decrease or possibly even eliminate the risk of neurologic injury.

The investigators propose to study the intra-operative events which put nerves at risk during the Latarjet procedure. By using neuromonitoring to determine exactly when there is a potential nerve injury during the procedure, the investigators will be able to modify what the investigators do at that step of the procedure, in order to decrease or possibly even eliminate the risk of neurologic injury. Modifications to our surgical technique in response to events observed on neuromonitoring would include repositioning the operative shoulder and upper extremity, and repositioning or removing retractors. The investigators believe this would lead to a significant decrease in the incidence of neurologic complications post-operatively. Since this operation is usually performed on young, active patients, the benefits of reducing or eliminating these complications would have a far-reaching impact both for the individual and for society. Above all, the investigators feel that this is an important patient safety initiative.

Inclusion Criteria:

• All patients of the two senior surgeons who will undergo the Latarjet procedure for shoulder instability will be considered for inclusion in the study.
• Our patients who have received prior approval from their insurance carrier to cover neuromonitoring during the surgical procedure will be enrolled.

Exclusion Criteria:

• Relative contraindications to transcranial electrical stimulation include: history of seizures, significant brain trauma, cerebral edema with mass effect, recent CVA, intracerebral devices (e.g., shunts, aneurysmal clips), skull defect and cardiac pacemaker. Patients with there conditions will be included in the study.

40 subjects were enrolled; however, there were some subjects that were excluded for reasons that are explained in the published paper that resulted from this study. The total number of subjects excluded was 6, leaving 34 participants to be analyzed.