Capitol Anesthesiology Association - Services - Regional Anesthesia

Complications of Brachial Plexus Block

The nerves of the upper extremity (i.e., the arm and hand) originate in the neck where they exit from the spinal cord. These nerves form a complicated web of nerves known as the brachial plexus. This network of nerves gives rise to the three main nerves that travel down the arm, carrying both messages of sensation (from arm and hand back to brain) as well as messages of movement (from brain to muscles). When a solution of a local anesthetic drug is injected in the proximity of the brachial plexus, it anesthetizes the nerves and interrupts the transmission of these messages. This results in numbness of the arm and hand as well as inability to cause the muscles in that area to move.

This form of anesthesia can thus provide good operating conditions for surgery on the arm or hand. As with all anesthetic techniques, there is a possibility of certain complications. There are several methods that have been developed to anesthetize the brachial plexus. Some of the methods make use of a nerve stimulator to help the anesthesiologist precisely locate the site of injection. The more widely used approaches are:

Axillary block is arguably the most widely taught and thus most frequently used approach to the brachial plexus. It involves an injection of local anesthetics into the axilla, or armpit. Axillary block is usually used for surgery on the hand. There are a variety of techniques used to precisely locate the nerves in order to place the anesthetic solution in just the right spot.

This is performed by inserting the needle just behind the collarbone, or clavicle. It is a often used for surgery or pain control of the elbow.

This approach is very similar to the supraclavicular block but differs in that the site of injection is closer to the base of the neck. It is also sometimes used for post-op pain management following surgery on the shoulder.

Brachial plexus blocks may be used when regional anesthesia is desired for surgery on the upper extremity. They have an advantage over Bier Block anesthesia in that with proper choice of anesthetic agent they can be made to last several hours and achieve enough numbness in the arm for tourniquets to be well tolerated (surgeons often desire the use of tourniquets to interrupt the circulation and provide bloodless operating conditions; unlike Bier Block, however, a tourniquet is not a requirement for brachial plexus block).