Cranial reconstruction
Cranial reconstruction was a form of cosmetic surgery used by Klingons.

After a cure was discovered for the Klingon augment virus, in 2154, Doctor Antaak doubted that his superiors in the Klingon Defense Forces would allow him to retain his position. Because of this, he told Dr. Phlox that he would "need to find a new specialty," suggesting "perhaps cranial reconstruction." In response, Phlox stated that he had "a feeling that [was] about to become very popular." ()
Medical procedures