Effect of local analgesia on movement of the equine back.
BACKGROUND
Diagnostic infiltration of local anaesthetic solution is commonly used in cases of equine back pain. Evaluation is subjective and it is not known how local analgesia of the back affects horses without clinical signs of back pain.


OBJECTIVE
To evaluate the effect of infiltration of local anaesthetics on the movement of the back in horses without clinical signs of back pain, and to evaluate the usefulness of kinematic studies as an objective and quantitative tool in evaluating local analgesia in clinical practice.


METHODS
The kinematics of the back in 10 clinically sound horses were measured on 2 occasions at walk and trot before and after injections with mepivacaine and sodium chloride around the interspinous spaces between T16 and L2. The kinematics were compared between the 2 occasions before injections and before and after each injection.


RESULTS
The range of motion (ROM) for dorsoventral flexion-extension (FE) of the back was increased significantly in all measured segments other than T10 at walk, as was lateral bending (LB) at T10, L3 and L5 after injection of mepivacaine. For lateral excursion (LE), total movement increased at all measured segments. At trot the only affected segment was L3, where the injection with mepivacaine decreased the ROM for FE. After injection of sodium chloride the ROM for FE increased at T13 and T17 at walk. Lateral bending and LE were not affected at walk. At trot, LB increased at L3 and L5.


CONCLUSIONS
Diagnostic infiltration of local anaesthetic solution affects the function of the back in clinically sound horses, which must be considered when interpreting the use of this clinical aid in assessing clinical cases of back dysfunction. Kinematics can qualitatively and quantitatively evaluate the effect of local analgesia of the back.
Holm
K Roethlisberger
KR
Department of Clinical Sciences, Division of Surgery and Medicine, Swedish University of Agricultural Sciences, S-750 07 Uppsala.
Wennerstrand
J
J
Lagerquist
U
U
Eksell
R
R
Johnston
C
C
D000698:Analgesia / Q000379:methods / Q000662:veterinary*; D000779:Anesthetics, Local / Q000494:pharmacology*; D000818:Animals; D001415:Back / Q000502:physiology*; D001416:Back Pain / Q000188:drug therapy / Q000503:physiopathology / Q000662:veterinary; D001696:Biomechanical Phenomena; D005080:Exercise Test / Q000662:veterinary; D005260:Female; D005684:Gait / Q000502:physiology*; D006734:Horse Diseases / Q000188:drug therapy / Q000503:physiopathology; D006736:Horses / Q000502:physiology*; D008124:Locomotion / Q000502:physiology; D008159:Lumbar Vertebrae / Q000502:physiology; D008297:Male; D008619:Mepivacaine / Q000494:pharmacology*; D016059:Range of Motion, Articular / Q000187:drug effects; D013904:Thoracic Vertebrae / Q000502:physiology
D000779:Anesthetics, Local; D008619:Mepivacaine