Brachial Plexus Blockade Causes Subclinical Neuropathy: A Prospective Observational Study.

The objective of this study is to determine subclinical changes in hand sensation after brachial plexus blocks used for hand surgery procedures. We used Semmes-Weinstein monofilament testing to detect these changes. We hypothesized that patients undergoing brachial plexus nerve blocks would have postoperative subclinical neuropathy detected by monofilament testing when compared with controls. In total, 115 hand surgery adult patients were prospectively enrolled in this study. All patients undergoing nerve-related procedures were excluded as well as any patients with preoperative clinically apparent nerve deficits. Eighty-four patients underwent brachial plexus blockade preoperatively, and 31 patients underwent general anesthesia (GA). Semmes-Weinstein monofilament testing of the hand was performed preoperatively on both the operative and nonoperative extremities and postoperatively at a mean of 11 days on both hands. Preoperative and postoperative monofilament testing scores were compared between the block hand and the nonoperated hand of the same patient, as well as between the block hands and the GA-operated hands. There were no recorded clinically relevant neurologic complications in the block group or GA group. A statistically significant decrease in sensation in postoperative testing in the operated block hand compared with the nonoperated hand was noted. When comparing the operated block hand with the operated GA hand, there was a decrease in postoperative sensation in the operated block hand that did not reach statistical significance. Brachial plexus blockade causes subtle subclinical decreases in sensibility at short-term follow-up, without any clinically relevant manifestations.