CPT® Code 64420

The procedure described by CPT® Code 64420 involves the injection of anesthetic agents and/or steroids into a single intercostal nerve, which is a type of nerve block. This intervention can serve both diagnostic and therapeutic purposes. The intercostal nerves are classified as mixed nerves, meaning they carry both sensory and motor fibers. They are responsible for innervating the skin and muscles of the upper extremities, thorax, and abdominal wall. These nerves emerge from the spinal cord and exit the posterior aspect of the intercostal membrane, located just distal to the intervertebral foramen. Following their exit, the intercostal nerves travel into the intercostal groove, which runs parallel to the ribs, and branches of these nerves can be found situated between the ribs. Typically, intercostal nerve blocks are performed at specific anatomical locations, most commonly along the posterior axillary line or just lateral to the paraspinal muscles at the angle of the rib. Prior to the injection, the healthcare provider identifies and marks the planned injection site(s) along the inferior border of the rib(s). The procedure involves the careful introduction of a needle beneath the inferior border of the rib, advancing it until it reaches the subcostal groove. Once the needle is correctly positioned, the anesthetic agent and/or steroid is injected to achieve the desired effect. For coding purposes, CPT® Code 64420 is utilized for the injection of a single intercostal nerve, while CPT® Code 64421 is designated for each additional intercostal nerve level that is injected.