Line block and inverted L-block

• Described here is desensitization of the flank for laparotomy.
• The line block can also be used to desensitize any area of the abdominal or thoracic wall (for example for umbilical hernia repair Umbilical hernia: surgical correction, thoracotomy, wound repair, or removal of a body wall mass).

Uses

• Enables standing right or left flank laparotomy Flank laparotomy (for procedures like cesarean section Cesarean section; displaced abomasum Left displaced abomasum: surgical correction; exploratory laparotomy; other surgery involving the gastro-intestinal tract, urinary tract or reproductive tract).
• Facilitates wound repair and removal of a mass involving the flank.
• As an adjunct in a patient under general anesthesia Anesthetizing cattle as part of multi-modal anesthesia and analgesia.

Advantages

• Inexpensive and minimal equipment needs.
• Minimal side effects.
• Allows standing surgery.
• Minimal patient recovery time.
• For advantages and disadvantages of Line vs. Inverted-L block, please see below under ‘Decision taking’.

Disadvantages

• Depending on accuracy of block placement, the area of desensitization and muscle relaxation can be variable, in particular, deeper tissue layers.
• The area of desensitization is restricted to the extent of the block in a dorsoventral direction.
• Good restraint of the animal is required.
• The high volume of anesthetic required poses a toxicity risk, in particular in smaller patients (like calves).
• No post-operative analgesia is provided.

Technical problems

• Care needs to be taken to infiltrate deeper tissue layers sufficiently.

Alternative techniques

• Paravertebral anesthesia Paravertebral block.
• Where patient recumbency is not an issue: general anesthesia Anesthetizing cattle or lumbo-sacral epidural anesthesia Epidural.

Time required

Preparation

• Aseptic site preparation (clipping and surgical scrub): 10 min

Procedure

• 5-10 min.
• Allow 10-20 min for block to take effect.

Decision taking

Criteria for choosing test

• Generic factors that determine most appropriate type of anesthesia.
• Both techniques are similar in ease of application. However, they each have their pros and cons:
  • The Inverted-L block has the advantage over the Line block of depositing local anesthetic away from the incision site, which may facilitate healing.
  • The infiltration along the incision site as part of a Line block may lead to disturbed wound healing or wound dehiscence. There may be little to no muscle relaxation with a Line block.
  • The Inverted-L block requires a larger volume of anesthetic compared to the Line block, and is restricted to body areas where the innervation comes from a dorsocranial or dorsocaudal direction (for the latter, use a ‘mirror’ inverted L-block, ie the vertical line is caudal to the horizontal line of the block).
  • The Line block can be applied in any area of the body wall .

Risk assessment

• Good restraint of the animal, in particular safeguarding against being kicked or self-injection or injury to the animal.
• Skin necrosis is a potential risk where a product containing adrenaline is used. Empirical evidence suggests that this risk is small.