What is Caudal Epidural Anesthetic?
Caudal epidural anesthetic is local anesthetic administered in the epidural space around the spinal cord, but not in the meninges, in the area adjacent to the tail. This produces analgesia in the posterior part of your horse's body, to the tail and perineal regions, that allows medical and surgical treatment to take place. This is usually performed to allow surgical or other invasive procedures to take place in your horse's perineal region while the horse is sedated and in the standing position, without causing any pain or discomfort to the horse. It may also be used on anesthetized horses to reduce pain and discomfort associated with surgery or treatment in that area. If pain relief of a long duration is required, a catheter can be placed in the epidural space and anesthetic provided on a continuous basis. Local anesthetic is restricted to the posterior region, the coccygeal region, of your horse's spine as local anesthetic further forward can interfere with your horse’s hind leg functioning and anesthetic reaching the cervical region affects phrenic nerves and results in interference with respiration. Usually, not enough anesthetic is administered to interfere with functioning of the hind legs, allowing the horse to remain standing. Your veterinarian will perform this procedure if required to conduct surgical or invasive medical procedures in the perineal region.
Book First Walk Free!
Caudal Epidural Anesthetic Procedure in Horses
Caudal epidurals are usually administered in the sacrococcygeal regions so as not to interfere with hind limb function. An intravenous line is usually established prior to caudal epidural to treat hypotension or other conditions that could arise during anesthesia. The area where the epidural is to be performed is clipped to remove hair and cleaned antiseptically. Your horse may be sedated; in a heavily sedated horse the ability to stand square may be impaired, making midline administration more difficult. In addition, a topical local anaesthetic such as lidocaine may be used prior to insertion of epidural needle. An 18 to 22 gauge needle 1.5 to 3.5 in length is used depending on the size of the horse. If multiple doses will be needed, a catheter is used. With the horse standing squarely the needle is placed on the midline perpendicular to the skin and pushed downward until the arcuate ligament is punctured and the epidural space accessed. To ensure access to the epidural space, air may be injected through the needle to see if resistance is encountered. No resistance should occur in the epidural space. Another method of ensuring appropriate location is to place a drop of saline into the needle hub, negative pressure in the epidural space will cause the drop to be aspirated into the epidural space. Once the needle is placed medication can be injected. Injection should be done slowly, e.g. 10ml per minute, so as not to cause compression of nerve endings.
As the anesthesia begins to take action the horse's tail will relax. Once anesthesia is established the medical procedure can begin. Duration of caudal epidural action varies between individual horses, but is usually effective for a few hours.
Efficacy of Caudal Epidural Anesthetic in Horses
Because of the risks associated with general anesthesia in horses, caudal epidural anesthetic for surgical interventions in the posterior region of the horse are increasing in popularity as they provide effective analgesia without rendering the horse unconscious.
Caudal Epidural Anesthetic Recovery in Horses
Your horse should be monitored during caudal epidural anesthesia to ensure that vital signs are not affected and as they recover from epidural administration. Do not leave a horse experiencing analgesia to the posterior of their body unsupervised, as lack of feeling in that area along with sedation, can interfere with motor coordination and lack of feeling can result in injury to the area. As it can take several hours for the effect of epidural to wear off, your horse should be supervised during this time.
Cost of Caudal Epidural Anesthetic in Horses
The cost for mileage and surgical procedure for which epidural is being provided varies widely, however, the cost of caudal epidural in your horse usually ranges from $75 to $200 depending on the cost of living in your location.
Horse Caudal Epidural Anesthetic Considerations
If infection or inflammation are occurring near the injection site or if spinal cord disease or musculoskeletal disorder are present, caudal epidural should not be performed, as complications including ataxia and loss of motor control can occur.
Local anesthetic applied to the wrong part of the body can result in respiratory distress and cardiac arrest. In addition, loss of motor control in the hind legs is possible. Caudal epidural is performed in horses to mitigate these possibilities. The caudal epidural space presents decreased risk for dural or CSF puncture, motor blockade and ataxia.
Appropriate preparation of the injection site will mitigate the risk of infection being introduced with the epidural locally or into the epidural region.
Hypotension is a risk, and careful monitoring of vital signs and medications administered via an established intravenous line will counteract this.
Caudal Epidural Anesthetic Prevention in Horses
The requirement for caudal epidural applies to surgical intervention in the posterior region. Preventing injury in your horse by removing hazards in the environment will greatly reduce the likelihood of your horse experiencing injuries to their posterior region requiring intervention. In addition, injuries resulting from breeding and parturition can be mitigated by providing careful monitoring during these processes and obtaining aid when required.