Perianesthesia analgesia, recovery efficacy, and financial impact of ultrasound-guided lumbar plexus and sciatic nerve analgesia in dogs undergoing tibial plateau leveling osteotomy
Warrit, Kanawee, author
Boscan, Pedro, advisor
Monnet, Eric, advisor
Steffey, Eugene, committee member
Twedt, David, committee member
Rao, Sangeeta, committee member
Fails, Anna Dee, committee member
Perioperative analgesia is critical for patients undergoing surgery because uncontrolled pain can result in deleterious consequences and predispose chronic pain. Therefore, developing an appropriate analgesia technique is crucial, and in this study, an analgesia protocol was investigated in dogs undergoing tibial plateau leveling osteotomy (TPLO). The TPLO is a surgical technique used to stabilize the stifle joint for treating cranial cruciate ligament disease. This surgical procedure is invasive and painful. Therefore, multimodal analgesia is often required for controlling pain associated with TPLO surgery. This study used ultrasound-guided regional anesthesia of the lumbar plexus and sciatic nerve as a component of multimodal analgesia to control perioperative pain compared to patients only receiving a standard systemic analgesia. The study was designed to evaluate the efficacy of regional anesthesia and to determine the financial impact of this additional multimodal procedure. We hypothesized that ultrasound-guided lumbar plexus and sciatic nerve blocks would provide a better analgesic effect intraoperative and postoperatively. The second part of the study we hypothesized that ultrasound-guided lumbar plexus and sciatic nerve blocks would increase the anesthesia cost. It would then be possible to determine a cost – benefit of the procedure. The study was designed as a prospective, randomized, blinded clinical trial. Twenty dogs underwent TPLO surgery were enrolled in the study and randomly assigned to regional analgesia (RA) or control (CON) group. Dogs in the RA group received 0.5% ropivacaine for ultrasound-guided lumbar plexus and sciatic nerve blocks. The total dose of ropivacaine for both blocks was 0.15 mg/kg. Dogs in the CON group received sterile 0.9% saline for the blocks. All dogs received 0.2 mg/kg of hydromorphone and 0.02 mg/kg of atropine for anesthesia premedication. Propofol was administered for anesthesia induction to perform endotracheal tube intubation. Isoflurane in oxygen was delivered using a circle rebreathing system to maintain anesthesia. The ultrasound-guided lumbar plexus and sciatic nerve blocks were performed prior to TPLO surgery. Fentanyl was used for intraoperative as rescue analgesia to reduce the response from surgical stimulation or with an increase in heart rate, respiratory rate, or mean arterial blood pressure. Isoflurane was adjusted to maintain the appropriate anesthesia plane. Hypotension was treated following a stepwise protocol, in a sequencing fashion. The treatment protocol was added until the complications was resolved. The treatment protocol started from decreased isoflurane vaporizer setting, lactate Ringer's solution bolus, hetastarch bolus, and dopamine administration. At extubation, the recovery quality and pain were evaluated. Dexmedetomidine was used to treat poor recovery quality and pain. During the postoperative 12 hours period, pain and recovery quality were assessed by Colorado State University acute pain scale, visual analog pain scale, and modified University of Melbourne pain scale. Fentanyl or methadone was used for postoperative rescue analgesia. Dexmedetomidine or acepromazine was administered to calm the patient. The amount of every drug used, complications management, and extra nursing care were recorded to evaluate the blocks' efficacy. The micro-costing technique was used to collect the financial data and was analyzed to determine the financial impact. In the clinical study, there was a statistically significant difference in the amount of intraoperative fentanyl administered for rescue analgesia between the groups (p = 0.02), with lesser doses given to the RA group. Hypotension was found in 40% of dogs in the RA group and 80% of the dogs in the CON group (p = 0.16). Dogs in the RA group required less intensive treatment than in the CON group. There was a statistically significant difference in the recovery scores between the groups, with those in the RA group having lower recovery scores (p = 0.04). In the postoperative period, the time to receive the first dose of rescue analgesia for dogs in the RA group was longer than dogs in the CON group (p=0.04). Micro-costing method was used for collecting the monetary information. The cost analysis was performed for evaluating the costs of dogs that received ultrasound-guided regional anesthesia with 0.5% ropivacaine and 0.5% sterile saline. The anesthesia fixed cost for the surgery was US$354. There was a statistically significant difference between the variable costs, with the RA group (US$82.65 (69.15-94.56); median (min-max)) having less anesthesia variable costs than dogs in the CON group (US$125.8 (55.23 to 156.35); p = 0.02). The additional cost for a charge per service of the use of ultrasound and electro-nerve stimulator machines (US$26.62) affects the total anesthesia cost for the RA group into both direction, it can enhance and save the total anesthesia cost. It can increases the total anesthesia cost by $US40.54 per dog and it can save the total anesthesia cost by $US35.17 per dog. From the clinical perspective, the number of dogs receiving TPLO surgery at the study hospital is approximately 160 cases per year. This number was used for estimating cost benefit per year performing nerve blocks for TPLO surgery and found that the nerve blocks would potentially increase the total cost for 160 dogs to US$6,486.40 per year but would decrease the total anesthesia cost by US$5,627.20 per year. Ultrasound-guided lumbar plexus and sciatic nerve regional analgesia was found to be an effective multimodal analgesia for TPLO surgery. The technique provided effective intraoperative analgesia that decreased rescue analgesia during surgery and led to better recovery from anesthesia for the dogs in this study. The ultrasound-guided analgesia technique would increase anesthesia costs but better analgesia, anesthesia, and decreased complications provided significant cost-saving benefits when performing regional analgesia for TPLO surgery.
Includes bibliographical references.
tibial plateau levelling osteotomy
ultrasound-guided lumbar plexus and sciatic nerve blocks