The occipital knob is a common midline skull protrusion on the back of the head. It is normal to have one but when its size becomes larger it can cause an undesired prominence. While a large occipital knob is particularly visible in the male with a shaved head an equal number of men with hair are still bothered by it. The distinctive feature of the inion, the medical name of this occipital bone protrusion, is that it has a narrow base compared to its projection. It is also at one of the thickest parts of the skull.
Despite its large projection the occipital knob does not need to have a very long incision for its removal. Nor it is a requirement to shave any hair over the incisional area if it exists. In this example the patient thought it was necessary to shave the scalp over the knob so he did it himself. But again this is not necessary but it does make it clear as to the incisional location and length. The incision does not need to be more than 2.5 to 3.0cms in length.
Once the incision is made the first thing to appreciate is that it is a long way down to the bone. The scalp is much thicker than most realize and the thickest part of the scalp is at the junction of the back of the head and the neck. The knob may appear superficial but it isn’t. It may be as much 1.5 to 2 inches down to the bone. Once the knob is located it is important to circumferentially dissect around it particularly on its inferior side where there are muscle fibers.
To reduce the bony knob through such a small incision a burring technique is used. A large round burr is used to come right down on top of the knob and slowly reduce it to its base. Once leveled down to the surrounding skull it is important to reduce the inferior end further as the back of the head has a curved convex shape so to fully reduce the knob it must go further inward. This will require removing some muscle attachments to get it reduced fully.
Once the knob is adequately reduced closure is done in two layers, the galea and the skin using resorbable sutures. No drain is needed. A circumferential head dressing is applied and removed the next day.
Occipital knob reduction is tremendously effective and can be done through a very small scalp incision that heals inconspicuously in most patients. Contrary to what is seen in this patient shaving the hair to perform the surgery is not needed. It makes the surgery easier but is not necessary.
Dr. Barry Eppley
World-Renowned Plastic Surgeon