A Randomized Comparison Between Subepineural and Conventional Ultrasound-Guided Popliteal Sciatic Nerve Block

Abstract

Compared with separate injections around the tibial and peroneal divisions, a single subepineural injection at the neural bifurcation provides a higher success rate and requires shorter performance, onset, and total anesthesia-related times. Further studies are required to validate the safety of the subepineural technique.

Subparaneural Versus Circumferential Extraneural Injection at the Bifurcation Level in Ultrasound-Guided Popliteal Sciatic Nerve Blocks

“…No motor response to nerve stimulation was observed. The onset time for surgical block in the subparaneural group was shorter than in the extraneural group (respectively, median [range] values at 11 [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] minutes and 17 minutes, for surgical block excluding the 6 failure patients), and sensory blockade of the tibial nerve lasted longer. With regard to the failure rate, the 6 patients presenting block failure (incomplete sensory blockade after 30 minutes) belonged to the extraneural group.…”

“…During the procedure, all patients received sedation via target-controlled infusion (propofol, Marsh model, concentration at the site of action 1.2 ng/mL). Ultrasound-guided lateral, short-axis, in-plane sciatic popliteal nerve blocks (linear array probe LA 435K, [8][9][10][11][12][13][14][15][16][17][18] MHz; Agile, Kontron Medical, France) were performed by anesthetists with more than 3 years' experience with ultrasoundguided blocks. The skin was prepared with an alcoholic povidoneiodine solution.…”

“…[5][6][7] Depending on where the needle tip is inserted and the spread of LA solution, significant differences in onset time and duration of sensory and motor blockades have been reported. [8][9][10][11][12][13] The recent literature highlights the importance of obtaining an extraneural concentric distribution of LA around the sciatic nerve 1,14,15 or an extraneural injection surrounding both tibial and peroneal nerves distal to the bifurcation. 12,13,16 In 2 studies, a proximal injection below the paraneural sheath seemed superior to an extraneural distal injection around both separate tibial and peroneal nerves.…”

Lower extremity regional anesthesia: essentials of our current understanding

“…Due to the increased resolution of US machines, LA injection inside this paraneural sheath is now possible. In 2011, Tran et al 196 compared a single LA injection inside the common paraneural sheath at the sciatic nerve bifurcation (ie, the subparaneural technique) with targeted supraparaneural injections around the TN and CPN. These authors observed that the subparaneural technique resulted in a higher success rate (84% vs 56%; p=0.032) as well as improved efficiency (decreased performance/onset/total anesthesia-related times and fewer needle passes).…”

Ultrasound guidance showing real-time local anesthetic extravasation during injection of two lateral popliteal sciatic nerve blocks

“…Some have suggested that ultrasound imaging does not have the ability to differentiate the epineurium from the complex fascial layer encompassing the sciatic nerve [4] . Others suggest that these two layers are the same [12] . In conclusion, this debate suggests that ultrasound technology has limitations in detecting exactly where local anesthetic is being injected in relation to tissue planes that currently require histological analysis to clearly define [10] .…”