Combination of intraneural injection and high injection pressure leads to fascicular injury and neurologic deficits in dogs

Abstract

High injection pressures at the onset of injection may indicate an intraneural needle placement and lead to severe fascicular injury and persistent neurologic deficits. If these results are applicable to clinical practice, avoiding excessive injection pressure during nerve block administration may help to reduce the risk of neurologic injury.

Histological confirmation of needle tip position during ultrasound-guided interscalene block: a randomized comparison between the intraplexus and the periplexus approach

“…[8][9][10]22 Despite our best efforts to avoid the hypoechoic roots using a standard approach under ultrasound guidance, it is alarming that two subperineurial (intrafascicular) injections occurred with the intraplexus technique. There are two explanations why this may have occurred: 1) operator difficulty to view the needle tip at all times and 2) the limitations of ultrasound or the operator to visualize all anisotropic fascicles and nerve layers within the interscalene groove.…”

“…1,2 This may be due to the limitation of conventional ultrasound to distinguish muscle fascia from epineurium and small fascicles, [3][4][5] such that mechanical nerve injury, barotrauma, or local anesthetic toxicity may result from unintended injection into critical nerve structures. 1,[6][7][8][9][10] This has recently led investigators to focus on how best to avoid nerves while still achieving a reliable block. No difference in block quality or onset time occurred when comparing a periplexus with an intraplexus technique for brachial plexus block at the interscalene groove.…”

ASRA Practice Advisory on Neurologic Complications in Regional Anesthesia and Pain Medicine

“…These techniques include paresthesia-seeking, peripheral nerve stimulation, defined minimal or maximal milliamperage for acceptance of a motor response, 30,31 ultrasound guidance, or monitoring of injection pressures. [31][32][33][34][35] Ultrasound guidance, advances in peripheral nerve stimulation, 36 and pressure monitoring in particular are relatively new technologies; therefore, clinical experience and scientific study regarding their potential role in injury avoidance are limited. 37 In patients with pre-existing clinical or suspected subclinical peripheral nerve injury, consideration should be given to modifying the regional technique to minimize the introduction of additional potential neural insults.…”

“…57 There are no data to establish the safety of performing ultrasoundguided blocks in anesthetized or heavily sedated patients. Similarly, recent data suggest that high pressures during the injection of intrafascicular local anesthetic is frequently, but not always, associated with neural injury in dogs, 34 and methods have been proposed to avoid high injection pressure. 35 In part because ultrasound and pressure monitoring are relatively new technologies, there are no human data to confirm or refute these findings.…”

Neurological deficit after a peripheral regional anaesthetic: flying on instruments, the black box, crash investigation and other aeronautics

“…Hadzic and his colleagues in particular have proposed that pressure be measured during the injection, and that there should be a limit of 15 lb.in )2 (approximately 100 kPa). If surpassed, the needle may be blocked, or in the fascia, or in a fascicle -in any of these events, the injection should not proceed [13]. Conversely, if the resistance to injection is low, then, in principle, the injection should be safe.…”