title: Evidence for the use of ultrasound in neuraxial blocks.
abstract: OBJECTIVE
  To summarize the existing evidence behind the role of ultrasonography in neuraxial anesthesia techniques.
  
  
  METHODS
  A literature search of the MEDLINE, PubMed, ACP Journal Club databases, and the Cochrane Database of Systematic Reviews was performed using the term ultrasonography combined with each of the following: spinal, intrathecal, epidural, and lumbar puncture. Only studies related to regional anesthesia or acute pain practice were included. Case reports and letters to the editor were excluded. Seventeen relevant studies were identified and included in this review.
  
  
  RESULTS
  Neuraxial ultrasonography is a recent development in regional anesthesia practice. Most clinical studies to date come from a limited number of centers and have been performed by very few and highly experienced operators. The existing evidence may be classified in 2 main content areas: (a) ultrasound-assisted neuraxial techniques and (b) real-time ultrasound-guided neuraxial techniques.
  
  
  CONCLUSIONS
  Neuraxial ultrasonography has been recently introduced to regional anesthesia practice. The limited data available to date suggest that it is a useful adjunct to physical examination, allowing for a highly precise identification of regional landmarks and a precise estimation of epidural space depth, thus facilitating epidural catheter insertion. Further research is needed to conclusively establish its impact on procedure success and safety profile, particularly in the adult nonobstetric population.
authors.affiliation: Department of Anesthesia & Pain Management, Toronto Western Hospital, University Health Network, Ontario, Canada. Anahi.perlas@uhn.on.ca
authors.forename: Anahi
authors.initials: A
authors.lastname: Perlas
mesh_terms: D000767:Anesthesia, Epidural / Q000379:methods*; D000775:Anesthesia, Spinal / Q000379:methods*; D019317:Evidence-Based Medicine; D006801:Humans; D008159:Lumbar Vertebrae / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D018084:Ultrasonography, Interventional