Introduction
An interscalene brachial plexus block is a medical procedure where medication is injected to numb the shoulder and upper arm before surgical interventions or the repositioning of a dislocated shoulder. This technique targets the nerves in the shoulder and arm, making it effective for surgeries in those areas. While primarily used for shoulder and upper arm procedures, it can also assist in hand and wrist surgeries, although additional anesthesia may be needed. The effects of the nerve block are temporary, generally lasting for several hours, after which normal sensation returns.
Anatomy
The spine consists of small bones known as vertebrae. The scalene muscles connect specific vertebrae in the neck (cervical spine) and upper body (thoracic spine) to the upper ribs on both sides. Nerves extend from the spinal cord, passing through the anterior and middle scalene muscles, and form a network called the brachial plexus. This plexus is responsible for supplying nerves to the muscles and skin of the chest, shoulders, and arms.
Causes
The primary purpose of an interscalene brachial plexus block is to temporarily numb the nerves responsible for sensation in the shoulder and upper arm before surgical or medical procedures. Additionally, this technique can be utilized to alleviate pain from various conditions affecting the shoulder and upper extremities.
Treatment
The interscalene brachial plexus block is performed before your surgery or medical procedure to numb the shoulder and upper arm. You will be dressed in a surgical gown and lie on your back on an operating table. Your head will be turned away from the side receiving the nerve block, which helps identify the neck muscles and anatomical landmarks. Your physician will locate the interscalene groove, the site for the injection, by feeling the neck muscles.
The area will be sterilized and covered. A local anesthetic will be applied at the injection site. Using ultrasound or electrical nerve stimulation, the doctor will locate the brachial plexus nerves. The correct nerve will twitch, indicating successful identification. Once confirmed, a needle will be carefully inserted to deliver the anesthetic medication before being removed.
The interscalene brachial plexus block will numb the shoulder and upper arm for several hours, facilitating surgery or medical procedures without pain. After the procedure, your arm may be placed in a sling for protection until feeling returns. Your physician will also prescribe pain medication to manage discomfort once the nerve block wears off.
