CPT® Code 21700

The procedure described by CPT® Code 21700 involves the surgical division of the scalenus anticus muscle, which is a muscle located in the neck. This procedure is performed to alleviate symptoms associated with thoracic outlet syndrome or cervical rib syndrome. Thoracic outlet syndrome occurs when there is compression of the brachial plexus, a network of nerves that control the arm and hand, often due to anatomical abnormalities such as the presence of a cervical rib or tightness of the scalenus anticus muscle. Cervical rib syndrome specifically refers to the compression caused by an additional rib that may develop from the seventh cervical vertebra. During the procedure, an incision is made above the clavicle to access the area. The surgeon exposes and incises the sternocleidomastoid muscle, which allows for better visibility and access to the scalenus anticus muscle. The scalenus anticus muscle is then divided, and any fibrous bands that may be compressing the brachial plexus are also cut and removed. If a cervical rib is present and contributing to the compression, further dissection is performed to reach the rib, which may be resected if it is determined to be exacerbating the condition. This procedure is critical for relieving nerve compression and improving symptoms related to these syndromes.