title: Lateral popliteal sciatic nerve block: a single injection targeting the tibial branch of the sciatic nerve is as effective as a double-injection technique.
abstract: BACKGROUND
  Evidence indicating that single- and double-injection techniques for inducing a sciatic nerve block via a posterior subgluteal approach yield a similar success rate prompted us to investigate whether the two anesthetic techniques yield a similar success rate via a lateral approach. We also hypothesized that, owing to the peculiar anatomic features of the sciatic nerve at the popliteal level, a single injection via the lateral approach might induce effective anesthesia by targeting the tibial nerve only.
  
  
  METHODS
  Ninety-six patients undergoing popliteal sciatic nerve block via a lateral popliteal approach for foot surgery were randomized to receive a single 30-ml injection of ropivacaine 7.5 mg/ml to block the tibial nerve (TN group, n= 32) or the common peroneal nerve (CPN group, n= 32), or two separate 15-ml injections (TN + CPN group, n= 32), after stimulation to evoke motor responses from the target nerves.
  
  
  RESULTS
  The mean time to obtain a complete sensory blockade (surgical anesthesia) was shorter in the TN group than in the CPN and TN + CPN groups (14 +/- 7 min vs. 23 +/- 17 and 21 +/- 14 min, respectively; P < 0.05). The success rate was similar in the TN and TN + CPN groups (94%) and, 25 min after the initial injection, was already better in these groups than in the CPN group (94% vs. 75%; P < 0.05).
  
  
  CONCLUSIONS
  A lateral popliteal sciatic nerve block obtained with a single 30-ml injection of ropivacaine 7.5 mg/ml after electrostimulation to locate the tibial nerve is as effective as multiple TN + CPN stimulation and injection, and local anesthesia has a significantly shorter onset time.
authors.affiliation: Department of Anesthesiology and Intensive Care, Sant'Andrea Hospital, Second Faculty of Medicine, University of Rome La Sapienza, Rome, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Arcioni
authors.forename: S
authors.initials: S
authors.lastname: Palmisani
authors.forename: M
authors.initials: M
authors.lastname: Della Rocca
authors.forename: S
authors.initials: S
authors.lastname: Romanò
authors.forename: M
authors.initials: M
authors.lastname: Mercieri
authors.forename: R A
authors.initials: RA
authors.lastname: De Blasi
authors.forename: P
authors.initials: P
authors.lastname: Ronconi
authors.forename: G
authors.initials: G
authors.lastname: Pinto
mesh_terms: D000577:Amides / Q000008:administration & dosage*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D004311:Double-Blind Method; D004558:Electric Stimulation; D005071:Evoked Potentials; D005260:Female; D005528:Foot / Q000601:surgery; D006801:Humans; D007267:Injections / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D019148:Neuromuscular Blockade; D000077212:Ropivacaine; D012584:Sciatic Nerve / Q000502:physiology
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine