title: Intraneural and perineural inflammatory changes in piglets after injection of ultrasound gel, endotoxin, 0.9% NaCl, or needle insertion without injection.
abstract: BACKGROUND
  Ultrasound gel nerve inflammation has been reported. We evaluated the extent and nature of inflammation after gel injection with endotoxin (positive), saline, or dry needle puncture (negative) controls after peripheral blocks in piglets.
  
  
  METHODS
  Selected nerves of 12 piglets were localized by landmarks and nerve stimulator. Forty-eight hours after injection, specimens were examined for immunohistochemical cell differentiation/quantification and cytokine expression by using quantitative polymerase chain reaction.
  
  
  RESULTS
  Both gel and endotoxin injections resulted in a significantly higher density of inflammatory cells (lymphocytes/granulocytes) as compared with needle insertions and/or saline injections (both P < 0.001). Cytokines were not detected in any of the specimens.
  
  
  CONCLUSIONS
  Perineural gel injections cause significant inflammation. The lack of cytokines suggests injectate-related changes rather than mechanical trauma.
authors.affiliation: From the *Clinical Department of Anesthesiology and Intensive Therapy, University Medical Center Ljubljana, Ljubljana, Slovenia; †Institute of Anatomy, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia; ‡Bia Ltd. Ljubljana, Slovenia; §Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia; ‖Savinian Veterinary Polyclinic, Zalec, Slovenia; ¶and College of Physicians and Surgeons, Columbia University, New York, New York.
authors.forename: Tatjana Stopar
authors.initials: TS
authors.lastname: Pintaric
authors.forename: Erika
authors.initials: E
authors.lastname: Cvetko
authors.forename: Malan
authors.initials: M
authors.lastname: Strbenc
authors.forename: Katarina
authors.initials: K
authors.lastname: Mis
authors.forename: Ozbalt
authors.initials: O
authors.lastname: Podpecan
authors.forename: Tomaz
authors.initials: T
authors.lastname: Mars
authors.forename: Admir
authors.initials: A
authors.lastname: Hadzic
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D017252:CD3 Complex / Q000032:analysis; D016207:Cytokines / Q000378:metabolism; D007839:Functional Laterality; D005782:Gels / Q000009:adverse effects*; D007150:Immunohistochemistry; D018950:Lipopolysaccharide Receptors / Q000032:analysis; D008070:Lipopolysaccharides / Q000009:adverse effects*; D009068:Movement / Q000502:physiology; D009339:Needles / Q000009:adverse effects*; D009443:Neuritis / Q000139:chemically induced / Q000473:pathology*; D009474:Neurons / Q000473:pathology*; D012313:RNA / Q000096:biosynthesis / Q000302:isolation & purification; D011826:Radial Nerve / Q000473:pathology; D012965:Sodium Chloride / Q000009:adverse effects*; D012996:Solutions; D013552:Swine; D014459:Ulnar Nerve / Q000473:pathology
chemical_list: D017252:CD3 Complex; D016207:Cytokines; D005782:Gels; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D012996:Solutions; D012965:Sodium Chloride; D012313:RNA