Diagnostic anaesthesia for hindlimb lameness

Question 1

What perineural blocks of the hindlimb need aseptic prep?

Answer 1

• If the working enviroment is grossly contaminated (muddy, long hair)
• If you are perfroming a low 4-point block (risk of entering the digital flexor tendon sheath)
• If it will help you sleep at night

Question 2

how can you restain a patient for diagnostic anaesthesia of the hindlimb?

Answer 2

• Capable handler
• Nose twitch?
• Chemical restraint
• Lift ipsilateral forelimb limb

Personal safety
* Based on case-by-case risk assessment
* A helmet is recommended
* Don’t be afraid to say no!

Question 3

Should you clip a leg before joint injection in horses?

Answer 3

Evidence would suggest that we should only clip if it makes palpation of landmarks easier

Clipping unnecessarily may increase skin contamination

Question 4

when perfroming local anaesthesisa of the metatarsophalangeal joint is a low 6-point block used?

Answer 4

no a low 4-point block is sufficient, however the dorsal metatarsal branches are inpoirtant for skin sensitivity

Question 5

what is the difference in location of the causes of fore and hindlimb lameness?

Answer 5

• Vast majority of forelimb lameness is localised to the distal limb
• Vast majority of hindlimb lameness is localised outside of the distal limb (fetlock region, tarsal region, stifle)

Question 6

what is the difference between perinural and synovial blocks?

Answer 6

• Perineural blocks – need to work sequentially from distal to proximal
  ◦ Each block adds additional areas of desensitization to the previous one
• Synovial blocks – much more specific to the structure injected
  ◦ Can return to block more distal structures

Question 7

Name each of these blocks:

Answer 7

Question 8

What ligament does the DBLPN nerve block anaesthetise and how is this done?

Answer 8

A fairly specific block for the proximal suspensory ligament

• Limb is held flexed and rested on the vets knee
• The flexor tendons are pulled medially to open up injection site
• Needle is advanced along the axial surface of the lateral splint bone
• 3ml of local anaesthetic solution is injected (resistance should be low)
• The horse is re-examined after 10 minutes