title: Thoracic paravertebral block: influence of the number of injections.
abstract: OBJECTIVE
  The purpose of this study was to assess the radiographic and clinical distribution of 1 to 4 paravertebral injections by use of the same total volume of local anesthetic mixture.
  
  
  METHODS
  Sixty-nine patients scheduled for surgical interventions suitable for bilateral PVB were included in the study and were randomly assigned to 1 of 3 treatment groups. Group 1 received 4 paravertebral injections on one side versus 1 injection on the contralateral side (23 patients), group 2 received 4 injections versus 2 injections (23 patients), and group 3 received 4 injections versus 3 injections (23 patients).
  
  
  RESULTS
  Sixty-one patients were included in the final analysis, which resulted in 368 thoracic paravertebral injections. Overall, 97% of the patients had adequate loss of sensation within the targeted area at the side of 4 injections, compared with only 11% for the single injections. The average vertical spread of contrast was found to be significantly greater in the set of 4 injections, with mean (SD) 6.5 (2.01) dermatomes, compared with the single injection, with 3.0 (1.19) dermatomes (P < .05). The average vertical spread of contrast and complete absence of sensation were significantly greater in the set of 4 injections compared with the set of 2 and 3 injections (P < .05).
  
  
  CONCLUSIONS
  The main finding of the present study was that multiple paravertebral injections resulted in more reliable radiographic and clinical distribution compared with a single-injection technique.
authors.affiliation: Anesthesia Department, Makassed General Hospital, Beirut, Lebanon. zouhnaja@yahoo.com
authors.forename: Zoher M
authors.initials: ZM
authors.lastname: Naja
authors.forename: Mariam
authors.initials: M
authors.lastname: El-Rajab
authors.forename: Mohamad A
authors.initials: MA
authors.lastname: Al-Tannir
authors.forename: Fouad M
authors.initials: FM
authors.lastname: Ziade
authors.forename: Khalil
authors.initials: K
authors.lastname: Tayara
authors.forename: Fadi
authors.initials: F
authors.lastname: Younes
authors.forename: Per-Arne
authors.initials: PA
authors.lastname: Lönnqvist
mesh_terms: D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000494:pharmacology; D003287:Contrast Media; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D007278:Injections, Spinal; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects; D011446:Prospective Studies; D013902:Radiography, Thoracic; D013904:Thoracic Vertebrae
chemical_list: D000779:Anesthetics, Local; D003287:Contrast Media