title: Ultrasound and nerve stimulation-guided L5 nerve root block.
abstract: METHODS
  Case series.
  
  
  OBJECTIVE
  Evaluation of ultrasound and nerve stimulation-guided L5 nerve root block technique.
  
  
  BACKGROUND
  Ultrasound-guided peripheral nerve block has become clinically applied. However, selective lumbosacral nerve root block is conducted under radiographic guidance, which involves patients and operators being exposed to radiation. In addition, it cannot be carried out easily during outpatient visits or at the bedside. We conducted L5 nerve root block, which is one of the most common lumbosacral nerve root block under ultrasonic guidance, using electrical nerve stimulation.
  
  
  METHODS
  We assessed the effectiveness of ultrasound and nerve stimulation-guided L5 nerve root block on 78 patients with L5 radicular syndrome. To compare ultrasonic guidance using electrical nerve stimulation with radiographic guidance, we used a contrast agent and assessed its distribution.
  
  
  RESULTS
  After nerve block, decreased sensation at L5 neural region and diminished/fully resolved pain was observed in all patients except for 3 in whom nerve block could not be conducted as their articular process protruded laterally. Concerning the response to stimulation, all except for these 3 felt the tapping sensation at their L5 neural regions, but no contraction of muscles was observed. The number of patients who showed an extraneural, paraneural, and intraneural pattern on contrast radiography was 71, 4, and 0, respectively.
  
  
  CONCLUSIONS
  Ultrasound-guided L5 nerve root block using electrical nerve stimulation is a safe and effective method.
authors.affiliation: Department of Orthopaedic surgery, Omigawa general hospital, Chiba, Japan. s-masaki@navy.plala.or.jp
authors.forename: Masaki
authors.initials: M
authors.lastname: Sato
authors.forename: Sumito
authors.initials: S
authors.lastname: Simizu
authors.forename: Ryo
authors.initials: R
authors.lastname: Kadota
authors.forename: Hirosi
authors.initials: H
authors.lastname: Takahasi
mesh_terms: D000328:Adult; D000368:Aged; D000779:Anesthetics, Local; D003287:Contrast Media; D004558:Electric Stimulation / Q000295:instrumentation / Q000379:methods; D004594:Electrophysiology / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation / Q000379:methods*; D009407:Nerve Block / Q000379:methods*; D011843:Radiculopathy / Q000000981:diagnostic imaging / Q000188:drug therapy*; D011859:Radiography / Q000379:methods; D013126:Spinal Nerve Roots / Q000000981:diagnostic imaging / Q000187:drug effects; D016896:Treatment Outcome; D014463:Ultrasonography / Q000295:instrumentation / Q000379:methods*
chemical_list: D000779:Anesthetics, Local; D003287:Contrast Media