This thesis describes the use of a paravertebral block in comparison with local portal blocks to determine the analgesic effects and ease of performing a laparoscopic closure of the nephrosplenic space in horses. The single study presented in this thesis describes the use of 12 research horses for a clinical trial, divided in two groups of six. One group received local anesthetic injection of 2% lidocaine into each of three surgical-portal sites in the abdominal flank and a sham paravertebral injection of saline at nerves T18, L1 and L2. The second group received a sham injection with saline at the local portal sites and 2% lidocaine injections for the paravertebral block. The study was blinded for the two surgeons and one technician associated with each surgery, but the anesthetist was not blinded. All participants were asked to complete a visual analog scale (VAS) at the end of each procedure to assess the overall quality of analgesia, sedation, and behavior exhibited during surgery. All surgeries were completed without major complications and no statistical differences were noticed between groups in VAS scores, duration of surgery, and time required to perform each block. The paravertebral nerve block and the local portal blocks provide similar conditions during surgery and can be used interchangeably for closure of the nephrosplenic space in horses.