title: The feasibility of surface landmark for coracoid infraclavicular brachial plexus block by ultrasonographic assessment.
abstract: BACKGROUND
  The coracoid infraclavicular block first introduced by Whiffler provides a safer and easily approach than classic infraclavicular block. In this technique, the anatomy-based puncture site is 2 cm medial and 2 cm caudal from the coracoid process. This prospective study was purposed to evaluate the feasibility of surface landmark-based coracoid block by ultrasonography.
  
  
  METHODS
  High-frequency ultrasonographic examination was performed in 80 volunteers along the vertical line 2 cm medial to the coracoid process. The C point (C) is defined as landmark-based puncture site. The U point (U) is defined as the ultrasonographically modified optimal puncture site. After identifying the neurovascular bundle, the extent of precision based on landmark was examined and ultrasonographic measurements were also done. Demographic data was applied to correlate with the deviation between C and U.
  
  
  RESULTS
  The landmark-based puncture site for coracoid infraclavicular block was found to have a fair precision rate of 74.4%, although not high enough to provide a reliable puncture in daily practice. There was a significant trend toward a more superior puncture site of 2.95 mm (95% CI, 1.2-4.7). In female subjects, U was 5.12 mm (95% CI, 2.91-7.33) superior to C which was statistically significantly (P < 0.001). In male subjects, U was not significantly superior to C.
  
  
  CONCLUSIONS
  Ultrasonographic guidance is suggested whenever anatomical precision is inadequate or meeting with great individual bodily variance which renders landmark-based technique difficult. However, if this facility is not available, the gender discrepancy in measurement should be seriously considered when coracoid process is used as the landmark.
authors.affiliation: Department of Anesthesiology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC.
authors.forename: Yi-Wei
authors.initials: YW
authors.lastname: Kuo
authors.forename: I-Chen
authors.initials: IC
authors.lastname: Lu
authors.forename: Mu-Kun
authors.initials: MK
authors.lastname: Yen
authors.forename: Lee-Ying
authors.initials: LY
authors.lastname: Soo
authors.forename: David Vi
authors.initials: DV
authors.lastname: Lu
authors.forename: Koung-Shing
authors.initials: KS
authors.lastname: Chu
mesh_terms: D000328:Adult; D000368:Aged; D001917:Brachial Plexus; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D011446:Prospective Studies; D012782:Shoulder / Q000000981:diagnostic imaging*; D014463:Ultrasonography