Axillary block by "selective" injections at the nerves involved in surgery using a peripheral nerve stimulator: a comparison with a "standard" triple-injection technique.
OBJECTIVE
A triple-injection technique (injections at the median, musculocutaneous, and radial nerves) for axillary block affords a high incidence of complete block (all the nerves below the elbow). However, in certain surgeries, only 1 or 2 nerves are involved in the surgical field. The aim of this prospective randomized study was to test the effectiveness of surgical anesthesia of a "selective" approach in which only the nerves involved in surgery were electrically located and injected.


METHODS
Three types of surgery were selected. Type 1 included surgery on the fifth finger, type 2 included superficial surgery (without bone involvement) on the palm or on the dorsum of the hand, and type 3 included any surgery on the first 3 fingers. For each type, 138 patients were enrolled and divided into 2 groups: group SEL in which only the nerves involved in the surgical field (1 or 2) were located and injected and group TNS in which a standard triple-nerve stimulation technique was used.


RESULTS
A lower rate of surgical anesthesia (84% vs 92%; P G 0.05)was recorded in group SEL considered as a whole: this was mainly due to the significant difference recorded in type 2 surgery (75% vs 93%;P G 0.05). More patients needed intravenous administration of fentanyl for tourniquet pain (18% vs 8%; P G 0.005) and of midazolam for intraoperative anxiety (20% vs 8%; P G 0.005) in group SEL considered as a whole. In type 1, improved patient comfort at block performance(P G 0.05), a 7-min saving on total anesthetic time (P G 0.001), and a higher need for midazolam administration (P G 0.05) were recorded in group SEL. In type 2, a higher need for midazolam administration(P G 0.05) was recorded in group SEL. In type 3, no clinically significant differences between the groups were recorded.


CONCLUSIONS
A standard triple-nerve stimulation technique seems to be preferable to the selective approach even when a limited number of nerves are involved in the surgical field.
Sia
Salvatore
S
Department of Anesthesiology, Centro Traumatologico Ortopedico, Azienda Ospedaliera Careggi, Italy. sia3@interfree.it
Lepri
Antonella
A
Marchi
Marco
M
D000759:Adjuvants, Anesthesia / Q000008:administration & dosage; D000328:Adult; D014151:Anti-Anxiety Agents / Q000008:administration & dosage; D001365:Axilla; D001917:Brachial Plexus; D002985:Clinical Protocols; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage; D006225:Hand / Q000294:innervation / Q000601:surgery*; D006801:Humans; D008297:Male; D008874:Midazolam / Q000008:administration & dosage; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D010147:Pain Measurement; D011446:Prospective Studies; D013997:Time Factors; D004561:Transcutaneous Electric Nerve Stimulation / Q000379:methods*; D016896:Treatment Outcome
D000759:Adjuvants, Anesthesia; D014151:Anti-Anxiety Agents; D008874:Midazolam; D005283:Fentanyl