Fig. 3. Perioperative peripheral nerve injuries were identified by searching three separate large databases. The Quality Assurance (QA) and Closed Claims (CC) databases are specific to the Department of Anesthesiology and were searched for possible cases of nerve injury. The institution-wide inpatient and outpatient billing code database includes all patient encounters throughout the institution over the same time period as the anesthetics in the QA and CC databases. Billing codes associated with peripheral nerve injury were selected and cross-referenced against patients who had anesthetics over the study period. The cases identified through the three methods were hand-reviewed. Many cases clearly did not fit the definition for perioperative peripheral nerve injury associated with anesthesia and/or positioning and were excluded. Of the remaining cases, 12 were unclear and reviewed by an expert panel. Nine of the 12 patients were eliminated. An additional five cases were eliminated because of lack of clear documentation supporting a peripheral nerve injury. One case of Horner’s syndrome postoperatively was also eliminated, as it did not fit the definition of perioperative peripheral nerve injury described in the Methods section. The total number of perioperative peripheral nerve injuries identified over a 10-yr period at our institution was 112 out of a possible 380,680 cases (0.03%).