Paravertebral thoracolumbar anaesthesia in 10 horses

The caudal border of the last rib was used as a reliable point of orientation while performing paravertebral thoracolumbar anaesthesia (PTLA) on 10 horses undergoing standing flank laparotomy. The local anaesthetic in all horses was 2% lidocaine. The PTLA procedure was completed in 9.8 +/- 1.8 mins (mean +/- sd). Sedation was provided by a combination of intravenous morphine with xylazine or detomidine. Overall analgesia, provided by the combination of PTLA and sedation, was rated as excellent in 2 horses and good in 6 horses. In the remaining 2 horses, overall analgesia was rated as fair because of incomplete analgesia at the ventral portion of the incision. Total time, from start of PTLA to end of surgery was 143.5 +/- 24.2 mins. Five horses responded mildly to suturing of the ventral portion of the incision. Apart from 1 horse which developed transient, unilateral hindlimb weakness intraoperatively, no other complications were noticed. We conclude that PTLA can easily be performed in the horse and, combined with systemic sedation, is an effective and safe method of providing analgesia for standing flank laparotomy.