Paravertebral Nerve Blocks

Paravertebral nerve blocks use local anaesthetic injected in the perineural region where the spinal nerves exit the vertebral canal. Commonly performed on the thriteenth, first and second lumbar nerves, as these innervate the flank, where this procedure is most useful. The most reliable technique use the cranial border of the transverse process of the vertebrae caudal to the nerve being blocked, inserting the needle 5-6cm off midline. However, this technique can be performed on cervival and thoracic regions also.

Agents

As for infiltrative methods, common agents used include lidocaine, bupvicaine, and mepvicaine.

Uses

This techniques provides anaesthesia for standing surgeries in large animals, such as casearean sections and left displaced abomasum correction surgery, instead of using other regional techniques. Cervical or thoracic blocks can be used for surgical procedure involving the thorax and forelimb also. Paravertebral blocks can be used to provide analgesia for fractures or injuries also.

Check region before proceeding to check that the block has worked correctly.

Advantages

• Provides analgesia and anaesthesia to the peritoneum unlike infiltrative methods.
• Better relaxation of muscles.
• Noticable rise in skin temperature if the block has been successful due to hyperaemia.

Disadvantages

• Sometimes difficult to insert the needle in the correct position.