Blocks Do Not Worsen Neurologic Outcomes In Patients With Upper Extremity Nerve Injuries

Originally published by our sister publication Anesthesiology News

NEW ORLEANS—Results from a small observational study have confirmed what its researchers found in an earlier retrospective study: The use of peripheral nerve blocks does not worsen neurologic outcomes in trauma patients undergoing reparative procedures for existing upper extremity nerve injuries, compared to general anesthesia.

Although the pilot study lacked sufficient numbers to draw definitive conclusions, the researchers were nevertheless confident that the results demonstrate that the use of regional anesthesia for trauma injuries involving peripheral nerves does not hinder patients’ recovery.

“It is suggested that second insults such as a peripheral nerve block to already-injured nerves may lead to worsened outcomes,” said Zhongheng Yin, MD, a resident at the University of Pittsburgh Medical Center. “What’s more, while the most recent ASRA [American Society of Regional Anesthesia and Pain Medicine] guidelines on neurologic complications hint that there may be increased risk of nerve injury when there is already preexisting nerve dysfunction, they didn’t specifically address acute nerve injury in the setting of trauma.

“So, it raises the question: Does peripheral nerve block in traumatic nerve injuries hinder recovery?”

In a previous retrospective analysis of hand and wrist nerve trauma, Yin and his colleagues at the institution found that peripheral nerve blockade provided similar if not superior recovery of nerve function compared to general anesthesia in such patients. With the current effort, they sought to perform the same comparison, this time in an ongoing prospective study.

“We believe several factors may play a role in our previous findings, including potentially improved vascular flow, especially in the postoperative period.”

No Differences Found

A total of 53 adult patients were enrolled in the trial between September 2021 and February 2022, all of whom had experienced acute trauma to the hand, wrist or forearm, and subsequently underwent a reparative procedure of either the digital, median, radial or ulnar nerves. Of these, 32 received a peripheral nerve block (mean age, 50.9 years; 59.4% males), while the remaining 21 did not (mean age, 41.7 years; 81.0% males). The investigators determined neurologic outcomes by reviewing follow-up clinic notes.

There were several demographic differences between the two groups. First, individuals suffering avulsion fractures more commonly received peripheral nerve blocks (46.9%) than those who did not (9.5%). Furthermore, more patients in the peripheral nerve block group experienced tourniquet use (93.8% vs. 71.4%) and repair of the median nerve (56.3% vs. 28.6%). Finally, the length of surgery was significantly shorter in patients who received a peripheral nerve block (108±46 minutes) than in those who did not (186±171 minutes).

Presenting at the 2022 annual meeting of the American Society of Anesthesiologists (abstract A2010), the researchers explained that no significant differences were found with respect to neurologic outcomes between patients who did and did not receive a peripheral nerve block.

“Although our results were comparable to those from our earlier retrospective study, it’s interesting to note that the non-block cohort might have been a little bit more complex, given less tourniquet use and longer surgical times,” Yin said. “As this is an ongoing study with a relatively small sample size, outliers may play a more significant role, and we certainly see that here.” The researchers also did not perform any statistical tests to consider potential confounders.

Given these shortcomings, the investigators recognized the need for more research on the topic.

By Michael Vlessides

Yin reported no relevant financial disclosures. The abstract was honored as one of the meeting’s best.