The Effect of Brachial Plexus Nerve Block on Distal Peripheral Nerve Conduction

Inclusion Criteria: * Male and female military health care beneficiaries 18 years and older, capable of providing informed consent indicating awareness of the investigational nature of the study, in keeping with institutional policy * Written informed consent must be obtained from each patient prior to entering the study * Patients must be willing to have a regional anesthetic nerve block placed prior to their scheduled procedure * Patients must be willing to have neurodiagnostic tests performed prior to placement and after placement of the regional anesthesia nerve block Exclusion Criteria: * Refusal to have a brachial plexus nerve block placed * Refusal to have serial nerve conduction studies performed * Contraindication for a regional anesthesia nerve block (allergy to local anesthetic, infection at site of injection, elevated coagulation time) * Presence of conditions affecting the hand or arm (e.g., injury, infection) that might preclude the performance of nerve conduction studies * Presence of known major abnormalities of nerve conduction, e.g., absent median sensory potential in a patient scheduled for carpal tunnel release * Presence of conditions affecting the contralateral hand or arm (e.g., injury, infection) that might preclude the performance of sensory and motor studies to test block or absence of a contralateral upper extremity