Equine Regional Anesthesia: Limb Holding Techniques

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Which local anesthetic agent is preferred by most clinicians for inducing regional anesthesia during the lameness examination?

Procaine HCl

Lidocaine HCl

Bupivacaine HCl

Mepivacaine HCl (correct)

Which diagnostic procedure is NOT mentioned as being used more effectively and economically after localizing pain with regional anesthesia?

CT

Ultrasonography

Endoscopy (correct)

Radiography

Which local anesthetic agent provides anesthesia that lasts 4–6 hr for humane relief of pain?

Procaine HCl

Lidocaine HCl

Mepivacaine HCl

Bupivacaine HCl (correct)

When might lidocaine HCl be the preferred local anesthetic agent during the lameness examination?

When different techniques of diagnostic analgesia are likely to be used Signup and view all the answers

How is the PDN block commonly performed?

With the limb held Signup and view all the answers

What is the erroneous terminology sometimes used for the PDN block?

Heel block Signup and view all the answers

What can a semi-ring block at the pastern anesthetize?

Dorsal branches of the digital nerve Signup and view all the answers

What does a positive response to a basisesamoid nerve block indicate?

Pain causing lameness is localized to the pastern Signup and view all the answers

What happens if a large volume of local anesthetic solution is injected during a PDN block?

Partial anesthesia of the proximal interphalangeal joint Signup and view all the answers

Where is local anesthetic solution deposited during an abaxial sesamoid nerve block?

At the base of the proximal sesamoid bones Signup and view all the answers

Which nerve block is usually performed after a negative response to the abaxial sesamoid nerve block?

Low palmar nerve block Signup and view all the answers

What are some complications of regional nerve blocks mentioned in the text?

Broken needle shaft, SC infection, synovial structure infection Signup and view all the answers

What is a common practice when facing the same direction as the horse while anesthetizing the foot?

Holding the foot between the knees for free hands Signup and view all the answers

What is a risk when facing in opposite direction as the horse while anesthetizing the foot?

Risk of injury if horse swings its limb caudally Signup and view all the answers

Why is local anesthetic solution detectable systemically a potential problem?

It may disqualify a horse from participating in competition Signup and view all the answers

What gauge and length of needle is typically used to anesthetize nerves below the carpus or hock?

25-gauge, 5/8-in. needle Signup and view all the answers

What is the purpose of depositing a small amount of local anesthetic solution subcutaneously using a 25-gauge needle before using a larger-gauge needle for nerve anesthesia?

To avoid pain or resentment by the horse Signup and view all the answers

Why are luer-lock syringes not recommended for use in perineural administration of local anesthetic solution?

They are difficult to attach to the needle after insertion Signup and view all the answers

What should be considered when directing the needle during insertion to anesthetize nerves in the distal portion of the limb?

It should be directed distally Signup and view all the answers

Why is it important to administer only the smallest effective volume of anesthetic solution when identifying a site of pain below the carpus or hock?

To avoid inadvertent anesthesia of adjacent nerves Signup and view all the answers

What is the purpose of using a wireless, inertial sensor–based system designed to evaluate lameness in subtly lame horses?

To monitor changes in gait objectively Signup and view all the answers

Why should a horse be consistently and sufficiently lame before regional anesthesia is performed?

To detect any improvement in gait after anesthesia Signup and view all the answers

What is the expected time frame for relief of pain and resolution of lameness after local anesthetic solution is administered into the fascia surrounding a nerve in the distal portion of the limb?

5 minutes Signup and view all the answers

What type of needles are recommended for use if there is a possibility that the horse may move during perineural administration of local anesthetic solution?

Spinal needles Signup and view all the answers

What could result from directing the needle proximally during insertion when anesthetizing nerves in the distal portion of the limb?

Unintended anesthesia of more proximal branches of the nerve Signup and view all the answers

What can exacerbate a subtle lameness in horses and lead to misinterpretation of regional nerve block results?

Exercising or lungeing the horse before examination Signup and view all the answers

Where should the palmar nerves be blocked to avoid misdirecting a needle into the digital flexor sheath?

At the level of the metacarpus Signup and view all the answers

What is the purpose of blocking the ramus communicans along with the palmar nerves?

To prevent sensory impulses from propagating through the ramus Signup and view all the answers

Where should local anesthetic solution be deposited to complete the 4-point block?

At the distal end of each splint bone Signup and view all the answers

What does a positive response to a low 4-point block after a negative response to an abaxial sesamoid nerve block indicate?

Pain in the fetlock Signup and view all the answers

When is the high palmar nerve block performed?

When the low 4-point block fails to improve lameness Signup and view all the answers

What is desensitized when anesthetizing the medial and lateral palmar nerves alone?

The flexor tendons and inferior check ligament Signup and view all the answers

How is the lateral palmar nerve block performed?

By inserting a needle over the medial aspect of the accessory carpal bone Signup and view all the answers

What is an alternative to the high palmar nerve block when pain is suspected in the proximal portion of suspensory ligament?

The lateral palmar metacarpal nerve block Signup and view all the answers

What should be done if the site of pain causing lameness cannot be localized by performing previously discussed nerve blocks?

Perform joint blocks of the carpus, elbow, or shoulder Signup and view all the answers

What is important regarding the order in which synovial structures are desensitized during joint blocks?

The order does not affect desensitization outcomes Signup and view all the answers

What is the purpose of evaluating the horse's gait within 15 minutes after administering a regional nerve block in the distal portion of the limb?

To assess the effectiveness of the nerve block Signup and view all the answers

Why might it be prudent to assess a horse's gait on a soft surface or after bandaging the distal portion of the limb when nerves above the hock or carpus are anesthetized?

To prevent abrasion to skin over the dorsum of the fetlock if the horse stumbles Signup and view all the answers

What should be done if a well-behaved, stoic horse does not react to stimulation of skin even though regional anesthesia was ineffective?

Regional anesthesia for the same dermatome on the contralateral limb should be assessed Signup and view all the answers

Why is aspiration before injection important when administering local anesthetic solution during regional anesthesia?

To prevent depositing the solution in unintended structures Signup and view all the answers

What is the best approach for skin preparation before administering regional anesthesia for short-haired horses?

Wiping the site with cotton soaked in 70% isopropyl alcohol until clean Signup and view all the answers

Why is it prudent to use a lip twitch or lip chain for fractious horses or for horses previously subjected to regional anesthesia?

To provide sufficient restraint Signup and view all the answers

Why does xylazine or detomidine have an advantage over acepromazine when providing sedation for horses undergoing regional anesthesia?

Acepromazine increases awareness of pain in lame limbs, while xylazine and detomidine decrease awareness of pain Signup and view all the answers

What determines the degree to which sedation or tranquilization interferes with assessment of gait during regional anesthesia?

The severity of lameness and the skill of the clinician performing the examination Signup and view all the answers

Why is restraining the horse in stocks during regional anesthesia of the distal portion of the limb discouraged?

It increases the likelihood of injury to the clinician Signup and view all the answers

Why is it necessary to assess skin sensation before performing regional anesthesia on a fractious horse?

To ensure that regional anesthesia will be effective Signup and view all the answers

What might result from nonsterile injection of a tendon sheath or joint during regional anesthesia?

Sepsis synovitis Signup and view all the answers

Why might some clinicians claim that acepromazine accentuates subtle lameness?

It makes fractious horses more aware of their environment and therefore more aware of pain in lame limbs Signup and view all the answers

Which nerves are commonly anesthetized along with the medial cutaneous antebracheal nerve?

Median and ulnar nerves Signup and view all the answers

What technique is used to administer regional anesthesia of the distal portion of the pelvic limb?

Low 4-point nerve block Signup and view all the answers

Where is the deep branch of the lateral plantar nerve blocked to anesthetize the proximal aspect of the suspensory ligament?

Above the point of the hock on the medial aspect of the limb Signup and view all the answers

What is a likely source of pain if lameness is ameliorated after a tibial nerve block, but not after a low 4- or 6- point block?

Tarsal joints Signup and view all the answers

Where is the tibial nerve blocked to exclude pain in the hock or regions distal to the hock?

~10 cm above the point of the hock on the medial aspect of the limb Signup and view all the answers

What technique is used to administer the high plantar nerve block?

~1 cm distal to the tarsometatarsal joint Signup and view all the answers

What can be evaluated accurately without anesthetizing the dorsal metatarsal nerves?

Most lamenesses of the pelvic limb Signup and view all the answers

Where is 3–4 mL of local anesthetic solution deposited if the proximal aspect of the suspensory ligament is suspected to be the site of pain causing lameness?