title: 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.
abstract: BACKGROUND
  We hypothesized that blocking the tibial and common peroneal nerves individually using ultrasound distal to sciatic bifurcation would decrease time to complete block compared with a block proximal to the bifurcation.
  
  
  METHODS
  Seventy-six patients undergoing foot or ankle surgery received a sciatic nerve block either proximal or distal to the point of bifurcation. A mixture of 28 mL 1.5% mepivacaine with 100 microg clonidine and 1 mL 8.4% sodium bicarbonate for a total of 30 mL was used. Ultrasound was used to guide needle adjustments to achieve circumferential spread. Block success was defined as a loss of sensation to pinprick in both nerve distributions within 46 minutes.
  
  
  RESULTS
  Patients in the tibial-peroneal group had significantly faster time to complete block than the sciatic group (19.2 vs 26.1 minutes; P = 0.006).
  
  
  CONCLUSIONS
  Blocking the tibial and common peroneal nerves in the popliteal fossa separately provides for a faster onset than a prebifurcation sciatic block.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Buys
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Arndt
authors.forename: Firoz
authors.initials: F
authors.lastname: Vagh
authors.forename: Anna
authors.initials: A
authors.lastname: Hoard
authors.forename: Neal
authors.initials: N
authors.lastname: Gerstein
mesh_terms: D000700:Analgesics / Q000008:administration & dosage; D000779:Anesthetics, Local / Q000008:administration & dosage; D003000:Clonidine / Q000008:administration & dosage; D005260:Female; D005528:Foot / Q000601:surgery; D006801:Humans; D007267:Injections; D008297:Male; D008619:Mepivacaine / Q000008:administration & dosage; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D010543:Peroneal Nerve / Q000000981:diagnostic imaging; D012584:Sciatic Nerve / Q000000981:diagnostic imaging; D012677:Sensation; D013979:Tibial Nerve / Q000000981:diagnostic imaging; D018084:Ultrasonography, Interventional
chemical_list: D000700:Analgesics; D000779:Anesthetics, Local; D008619:Mepivacaine; D003000:Clonidine