Is a double-injection technique superior to a single injection in posterior subgluteal sciatic nerve block?
OBJECTIVE
Currently, no information is available on the effects of a double-injection technique on onset time and efficacy following subgluteal sciatic nerve blockade. We hypothesized that the success rate and time to onset of subgluteal nerve block following a double-injection technique would be superior to that after a single injection.


METHODS
Fifty ASA I or II patients undergoing foot or ankle surgery randomly received a single or double injection subgluteal sciatic nerve block. Group S (n=25) received a single injection of 30 ml of 0.75% ropivacaine to the sciatic nerve. In Group D (n = 25), 15 ml of the same solution was injected to each sciatic nerve component. Completion of sensory and motor blockade, and patient acceptance, was evaluated by a blinded anesthesiologist.


RESULTS
Complete sensory and motor blockade of the foot was achieved faster with the double injection (7.4 [5.9-8.8] min and 12.3 [10.4-14.2] min, respectively) than with the single-injection technique (12.5 [10.7-14.3] min and 18.8 [16.7-21.0] min, respectively) (P<0.001 and P<0.001, respectively). Success rate and acceptance were similar in both groups. Severe or moderate discomfort during the procedure was less frequent after a single injection (P = 0.013).


CONCLUSIONS
Both the single- and double-injection technique for subgluteal sciatic nerve blockade resulted in acceptable anesthesia in most patients. The double injection generated a faster onset of anesthesia than the single injection. However, the double-injection technique caused more patient discomfort during establishment of the nerve block.
Taboada
M
M
Department of Anesthesiology, Hospital Clínico Universitario de Santiago, Santiago de Compostela, Spain. manutabo@mixmail.com
Alvarez
J
J
Cortés
J
J
Rodríguez
J
J
Atanassoff
P G
PG
D000577:Amides / Q000008:administration & dosage*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D011446:Prospective Studies; D000077212:Ropivacaine; D012584:Sciatic Nerve
D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine