Is regional anesthesia safe in tibia fractures?
A recent study does not shed as much light on the topic as one would hope
Performing regional anesthesia for long bone fractures is controversial due to a concern of masking pain which could otherwise lead to the diagnosis of acute compartment syndrome. But is avoiding regional anesthesia in these patients really necessary? After all, the benefits of regional anesthesia for controlling pain and decreasing opioid use are significant. Furthermore, these is thought that ischemic pain is not blunted by regional anesthesia as is evidenced by patients experiencing tourniquet pain following a spinal anesthetic.
A recent paper by Kakalecik and colleagues sought to shed light on the subject by retrospectively looking at patients with tibia fractures who did or did not receive regional anesthesia. Acute compartment syndrome is most commonly seen following long bone fractures. Because of the small fascial compartment surrounding the tibia, tibia fractures have a higher risk of developing compartment syndrome. The study included non-pregnant, adult patients with tibia fractures at a single level-one trauma center from January 2015 until April 2022. Patients with known neurological injury, ipsilateral knee dislocations, and those who underwent prophylactic fasciotomy were excluded. Missed acute compartment syndrome was defined as having a motor deficit at three-months postop.
Patients had received either a single shot regional block with 15-20 mL of 0.2% ropivacaine (n = 48), and 0.2% ropivacaine peripheral nerve catheter without an initial bolus (n = 538), or no regional anesthesia (n = 176).1 The incidence of missed compartment syndrome was 0.7% (4/610, 95% CI, 0.2%-1.7%) in those receiving regional anesthesia compared to 1.7% (3/181, 95% CI, 0.4%-4.8%) in those not receiving regional with no significant difference (p = 0.19). All of the missed cases in the regional group were in those who had nerve catheters. Not surprisingly, patients who had regional anesthesia received lower morphine milligram equivalents (MME) in the first 24 hours compared to those without regional.
The major limitation of this study is its retrospective nature allowing for possible confounding. When looking at the injury severity score (ISS) of patients, this becomes a concern. Patients who received regional anesthesia had a lower mean ISS (mean difference -7.2, 95% CI, -8.6 to -5.9) and lower incidence of Gustilo-Anderson type IIIA or IIIB injuries. Unfortunately, criteria detailing who could receive regional anesthesia were not included in this paper.
While the lack of significant difference between the groups is encouraging, I do not think there is enough information to say anyone with a tibia fracture can safely receive regional anesthesia. These results suggest that regional anesthesia is safe enough to warrant an RCT looking at single shot blocks and peripheral nerve catheters in patients with tibia or other long bone fractures. Until that time, these patients should be offered regional anesthesia on a case-by-case basis after discussion with the surgeon.
Here, there appears to be an error in the paper. I took these numbers from Table 3. Unfortunately, they do not add up correctly. The total number of patient is listed as 791. Summing the tibia shaft fractures (n = 369) and tibia plateau fractures (n = 422) equals 791. However, summing the perineural catheter (n = 538), single shot (n = 48), and no regional anesthesia (n = 176) only amounts to 762. Elsewhere in the paper it lists the number not receiving regional as 181; correcting for that would still only bring the total to 767. In multiple places, the total number receiving regional is listed as 610, but 538 + 48 does not equal 610. Adding 610 to 181 does equal the listed total number of of 791. I reached out to the lead author in hopes of getting clarity, but I have yet to hear back. I am hopeful that these errors represent clerical errors and not significant errors which would change the results.