Comparison of the parasacral approach and the posterior approach, with single- and double-injection techniques, to block the sciatic nerve.
BACKGROUND
The purpose of this study was to compare parasacral and Winnie's single- or double-injection approaches for sciatic nerve block.


METHODS
One hundred fifty adults scheduled to undergo lower limb surgery were randomized to receive on the sciatic nerve 20 ml ropivacaine, 0.75%: single bolus for parasacral and Winnie's single injection. For Winnie's double injection, the peroneal and tibial nerves received separately 10 ml plus 10 ml. Blocks were performed with the use of nerve stimulator (intensity < 0.5 mA, 1 Hz). For the parasacral method, a line was drawn between the posterior superior iliac spine and the ischial tuberosity; needle entry was at 6 cm inferior to the posterior superior iliac spine.


RESULTS
The groups were similar. Time to perform the block was 2 (1-5) min for the parasacral method, with no difference from Winnie's single injection (3 [1-10] min), but was shorter with double injection (5.5 [2-15] min) (P = 0.0001). Onset of sensory block was similar in the parasacral (25 [7.5-50] min) and Winnie single-injection groups (25 [5-50] min) but significantly longer in the double-injection group (15 [5-50] min). Success rates for complete block were similar in the parasacral (66%) and Winnie's double-injection groups (68%) after 30 min but higher in the Winnie's single-injection group for tibial sensory and motor block (48%) (P < 0.017).


CONCLUSIONS
Time to perform a parasacral block was short, and the parasacral approach had a high success rate and a short onset time. Therefore, this block might be a useful alternative to Winnie's modification for sciatic nerve block.
Cuvillon
Philippe
P
Fédération des Département Anesthésie Douleur et Urgences Réanimation, CHU Nîmes, France. philippe.cuvillon@wanadoo.fr
Ripart
Jacques
J
Jeannes
Pascal
P
Mahamat
Aba
A
Boisson
Christophe
C
L'Hermite
Joel
J
Vernes
Eric
E
de la Coussaye
Jean Emmanuel
JE
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000577:Amides; D000779:Anesthetics, Local; D005260:Female; D006801:Humans; D007085:Ilium; D007866:Leg / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D019148:Neuromuscular Blockade; D010147:Pain Measurement; D010543:Peroneal Nerve; D011229:Preanesthetic Medication; D000077212:Ropivacaine; D012584:Sciatic Nerve / Q000033:anatomy & histology*; D013979:Tibial Nerve
D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine