Clinical and histological effects of the intrathecal administration of methylprednisolone in dogs.
BACKGROUND
Methylprednisolone is one of the most commonly used steroids for management of chronic back pain via epidural injection. Its inadvertent injection into the intrathecal space is associated with complications such as adhesive arachnoiditis.


OBJECTIVE
The present study aimed to assess the clinical and histological changes associated with the injection of methylprednisolone into the intrathecal space of dogs.


METHODS
A randomized, double blind, controlled animal trial.


METHODS
After approval by the animal research ethics committee, 14 dogs were studied in a randomized double blind controlled trial. They were assigned to one of 2 groups: Group I received 1 mL of 0.9% normal saline; Group II received 1 mL (1.15mg/kg) of methylprednisolone into the intrathecal space. Animals were clinically evaluated for 21 days, and then sacrificed. The lumbar and sacral portions of their spinal cords were removed for histological examination.


RESULTS
In Group I, there were no clinical or histological changes. All animals in Group II showed no clinical changes but all exhibited histological changes in the spinal cord. The main histological changes consisted of meningeal thickening and lymphocytic infiltrates in the blood vessels. In 3 animals, adhesion of pia, arachnoid, and dura matter was noted and the nerve roots were surrounded by fibrosis. In one animal, necrosis of the spinal cord was evident.


CONCLUSIONS
The limitations of the present study include: small sample of animals (n=14), relative short clinical follow-up (21 days), and use of a commercially available drug solution, which is not preservative free.


CONCLUSIONS
The present study demonstrated that the intrathecal administration of commercially available methylprednisolone was responsible for causing histological changes in the spinal cord and meninges of the animals studied.
Lima
Rodrigo Moreira
RM
São Paulo State University Botucatu, Sao Paulo. rmelima@gmail.com
Navarro
Lais H
LH
Carness
Jeffrey M
JM
Barros
Guilherme A
GA
Marques
Mariangela E A
ME
Solanki
Daneshvari
D
Ganem
Eliana M
EM
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000009:adverse effects*; D001416:Back Pain / Q000188:drug therapy; D004285:Dogs; D007278:Injections, Spinal / Q000009:adverse effects*; D008578:Meninges / Q000187:drug effects / Q000473:pathology*; D008775:Methylprednisolone / Q000008:administration & dosage / Q000009:adverse effects*; D013116:Spinal Cord / Q000187:drug effects* / Q000473:pathology; D000267:Tissue Adhesions / Q000139:chemically induced
D000893:Anti-Inflammatory Agents; D008775:Methylprednisolone