The Posterior Approach to the Sciatic Nerve in the Popliteal Fossa: A Comparison of Single- Versus Double-Injection Technique

Abstract

We compared single-injection and double-injection of the sciatic nerve with nerve stimulation in the posterior popliteal approach using mepivacaine 1% in a prospective, randomized and single-blind study to evaluate effectiveness, delay of onset, and complications in patients undergoing foot and ankle surgery. In the single-injection group (Group S, n = 30), 25 mL of mepivacaine 1% was administered after eliciting foot inversion or plantar flexion. In the double-injection group (Group D, n = 30), 12.5 mL of the solution was injected after eversion or dorsiflexion and 12.5 mL after plantar flexion of the foot. Mean differences (SD) between the two groups from onset time to complete sensory block were not significant (21.9 [14.2] min vs 22.1 [13.8] min) except for the superficial peroneal nerve block (18 [13] min vs 11.4 [7.5] min, Group S and D, respectively; P < 0.05) and, in Group D, between the superficial peroneal and tibial nerve blocks (11.4 [7.5] min vs 22.3 [11.3] min, respectively; P < 0.05). Complete analgesia was achieved in 77% of Group S patients and in 87% of Group D (P = 0.22). Complete analgesia of the deep peroneal nerve was achieved in 80% and 97% in Group S and D, respectively; P < 0.05. There were more paresthesias during block procedure in Group D (17% vs 40%) (P < 0.05). We conclude that double-nerve stimulation of the sciatic nerve gives similar complete onset times and overall success rate to single-nerve stimulation and more paresthesias during block performance.

Lower extremity regional anesthesia: essentials of our current understanding

“…No intergroup differences were found in performance times, number of attempts, and success rates (71%–82%). Another RCT (n=60), comparing single-injection and double-injection techniques, reported similar success rates (77%–87%), sensory onset times as well as total anesthesia-related times 187. However, a decreased performance time (4.6±2.8 vs 5.9±3.1 min; p=0.03) and incidence of paresthesia (17% vs 40%; p=0.04) were noted with a single-injection technique.…”

Ultrasound-Guided Sciatic Nerve Block in the Popliteal Fossa Using a Lateral Approach: Onset Time Comparing Separate Tibial and Common Peroneal Nerve Injections Versus Injecting Proximal to the Bifurcation

“…[3][4][5][6][7] However, a double-stimulation technique is not synonymous to separate tibial and common peroneal nerve injections, especially considering that most of these studies used an injection site at or above the expected level of bifurcation of the sciatic nerve. 8 Therefore, given the variability in the point of bifurcation and the blind nature of a stimulating technique, these studies do not definitively determine whether a prebifurcation sciatic block is associated with a different onset time than individual tibial and common peroneal nerve blocks.…”

A review of approaches and techniques for lower extremity nerve blocks

“…36,49,58 In contrast, three other RCTs (pertaining to the subgluteal, posterior and lateral popliteal approaches) failed to detect any such difference. 52,56,59 Although a review of the optimal LA dose required for sciatic nerve blockade exceeds the scope of this paper, it is interesting to note that the studies that found an improved success rate with two injections used a total dose of 20 mL of LA. In contrast, those that did not employed a larger volume (25-30 mL).…”

“…However, patients receiving a single injection reported fewer paresthesiae (17 vs 40% of patients; P = 0.04). 56 Although observational studies have suggested that the optimal evoked motor response for posterior popliteal sciatic blockade is inversion, this finding requires further validation with RCTs. 57 Two RCTs have compared single and double-injection techniques for the lateral popliteal approach with conflicting results.…”