title: Histopathological alterations after single epidural injection of ropivacaine, methylprednizolone acetate, or contrast material in swine.
abstract: OBJECTIVE
  The consequences from the injection of different types of drugs in the epidural space remains unknown. Increasing evidence suggests that localized inflammation, fibrosis, and arachnoiditis can complicate sequential epidural blockades, or even epidural contrast injection. We investigate the in vivo effect of epidural injections in the epidural space in an animal model.
  
  
  METHODS
  A group of ten male adult pigs, five punctures to each at distinct vertebral interspaces under general anesthesia, were examined, testing different drugs, used regularly in the epidural space (iopamidol, methylprednisolone acetate, ropivacaine). Each site was marked with a percutaneous hook wire marker. Histological analysis of the epidural space, the meninges, and the underlying spinal cord of the punctured sites along with staining for caspase-3 followed 20 days later.
  
  
  RESULTS
  The epidural space did not manifest adhesions or any other pathology, and the outer surface of the dura was not impaired in any specimen. The group that had the contrast media injection showed a higher inflammation response compared to the other groups (P = 0.001). Positive staining for caspase-3 was limited to <5% of neurons with all substances used.
  
  
  CONCLUSIONS
  No proof of arachnoiditis and/or fibrosis was noted in the epidural space with the use of the above-described drugs. A higher inflammation rate was noted with the use of contrast media.
authors.affiliation: 2nd Department of Anesthesiology-Pain Unit, School of Medicine, Attikon University Hospital, University of Athens, Athens, Greece.
authors.forename: Maria-Chrysanthi
authors.initials: MC
authors.lastname: Kitsou
authors.forename: Georgia
authors.initials: G
authors.lastname: Kostopanagiotou
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Kalimeris
authors.forename: Demetrios
authors.initials: D
authors.lastname: Vlachodimitropoulos
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Soultanis
authors.forename: Chrysanthi
authors.initials: C
authors.lastname: Batistaki
authors.forename: Alexis
authors.initials: A
authors.lastname: Kelekis
mesh_terms: D000577:Amides / Q000008:administration & dosage*; D000818:Animals; D016009:Chi-Square Distribution; D003287:Contrast Media / Q000008:administration & dosage*; D004388:Dura Mater / Q000187:drug effects; D004824:Epidural Space / Q000187:drug effects*; D005471:Fluoroscopy; D007150:Immunohistochemistry; D007268:Injections, Epidural; D007479:Iopamidol / Q000008:administration & dosage*; D008297:Male; D008775:Methylprednisolone / Q000008:administration & dosage / Q000031:analogs & derivatives*; D000077555:Methylprednisolone Acetate; D000077212:Ropivacaine; D013552:Swine
chemical_list: D000577:Amides; D003287:Contrast Media; D000077555:Methylprednisolone Acetate; D000077212:Ropivacaine; D007479:Iopamidol; D008775:Methylprednisolone