Regional Anesthesia Does Not Increase the Risk of Postoperative Neuropathy in Patients Undergoing Ulnar Nerve Transposition

Unlabelled: The use of regional anesthetic techniques in patients with preexisting neuropathies has been widely debated. The possibility of needle- or catheter-induced trauma, local anesthetic toxicity, or neural ischemia during regional blockade may place patients with underlying mechanical, ischemic, or metabolic neurologic derangements at increased risk of progressive neural injury. We evaluated the safety of regional versus general anesthesia in patients with a preexisting ulnar neuropathy undergoing ulnar nerve transposition. All patients (n = 360) who underwent ulnar nerve transposition at the Mayo Clinic from 1985 to 1999 were retrospectively studied. A general anesthetic was performed in 260 (72%) patients. The remaining 100 (28%) patients received an axillary block, including 64 patients in whom an ulnar paresthesia or nerve stimulator motor response was elicited at the time of block placement. Patient characteristics, the severity of preoperative ulnar nerve dysfunction, and surgical variables were similar between groups. Anesthetic technique did not affect neurologic outcome (new or worsening pain, paresthesias, numbness, or motor weakness) immediately after surgery or at 2 or 6 wk after surgery. All six patients in the Axillary Block group who reported new or worsening neurologic symptoms after surgery had received bupivacaine in combination with either an ulnar paresthesia or motor response. By using logistic regression, bupivacaine was identified as an independent risk factor for worsening of ulnar nerve function compared with other local anesthetics. We conclude that axillary blockade is a suitable anesthetic technique for this procedure.

Implications: The use of regional anesthetic techniques in patients with preexisting neuropathies has been widely debated. Theoretical concerns include the risk of progressive nerve damage from direct needle trauma or local anesthetic toxicity. This investigation, however, supports the safety of axillary blockade in patients with preexisting ulnar neuropathy undergoing ulnar nerve transposition.