Proximal lumbar paravertebral nerve block in cattle

Question 1

Indication

Answer 1

• Standing animal: right or left sided flank laparotomy

Question 2

Preinfusion procedures

Answer 2

• Prepare the injection site
• Preanesthetic sedation or analgesia as needed (IV route suggested)
• Excessive sedation may cause the animal to lie down

Question 3

Materials

Answer 3

• 4- to 5-inch (10-12 cm), 16- to 18-gauge spinal needle
• 1-inch (2,5 cm), 14-gauge guide needle to act as a cannula through the skin (preferred) or a
bayonet-tip blade to make a small stab incision in the skin to facilitate needle insertion
• 20-ml plastic syringe
• 2% lidocaine (with or without epinephrine)

Question 4

Basic Technique

Answer 4

• To locate the transverse process L1: count backward from L5 (the last palpable transverse process)
• Block the nerve:
o NT13 along the cranial edge of transverse process L1
o NL1 along the caudal edge of transverse process L1
o NL2 along the caudal edge of transverse process L2
• Guide needle:
o 4 to 5 cm (2 to 2.5 inches) lateral to the dorsal midline
o 5 ml of 2% lidocaine to anesthetize the skin
o The needle should be nearly vertical
o Move the needle up and down
o Inject slowly: 10 to 15 ml of 2% lidocaine:
▪ about 1 cm (0.5 inch) above
▪ 1 cm (0.5 inch) below the edge of the transverse process
o Allow 10 to 15 min. for proper anesthesia
o Both dorsal and ventral branches

Question 5

Common causes of failure

Answer 5

• Identification of lateral process of L1
• Needle at an angle rather than straight up and down
• Injection is too quickly (not spreading out the aesthetic
solution)