Injection of scars. Scars are often sites of dysfunctional nerve tissue. Direct injection of scars with local anesthetic is thought not only to help restore function of damaged nerve cells but has a secondary benefit of reducing the mechanical “pull” of the scar on other normal tissue. For example, a large scar on a patient’s sternum acquired from open-heart surgery may put unnatural tension on the thoracic spine, causing back pain. Injections into the scar soften it and reduce the pull.