Depressor anguli oris (DAO) excision



The depressor anguli oris (DAO) muscle attaches to the corner of the mouth and the bottom of the mandible  (lower jaw), just to the side of the chin. It is one of the muscles which helps make a frown. Often, patients with chronic facial palsy from recovered Bells Palsy, Ramsay Hunt syndrome, Lyme disease, acoustic neuroma surgery, or trauma, have too much activity in this muscle on the affected side of the face. This hyperactivity of the frown muscle pulls down on and restricts the smile, decreasing its ability to move upward. This chronic hypertonicity and inappropriate activation of the DAO muscle can also cause tightness, spasm and pain in the cheek and mouth area. 

One option to improve the smile and also alleviate some of the pain and tightness in this area is to use Botox to weaken the muscle and thus help unlock the smile. Similarly, another option is to actually release the muscle itself with this office-based DAO resection. This procedure, unlike Botox, is a permanent solution and does not need to be re-administered every 3-4 months. Additionally, sometimes resection of the DAO muscle will provide patients with a better smile than that which is achieved with Botox, which is another benefit to moving forward with the procedure.

              The procedure itself is performed in the office, and takes 30-45 minutes. Numbing medication is injected inside the mouth and a little bit over the chin as well.  An incision is made inside the lower lip, and fibers of the muscle are identified and removed.  We then place a few dissolving stitches to close the incision, and patients are given a few days of an antibiotic. Patients can eat and drink normally after the numbing medication wears off (about 2-3 hours). As patients heal, they may develop some swelling on the inside of the mouth over the area where the muscle was removed. This phenomenon is completely normal, and resolves with time- most patients feel like they have some moderate swelling and tenderness for a full 2 weeks after the procedure. After three weeks, patients are encouraged to begin a little gentle scar tissue massage to the area to expedite resolution of the swelling. Please see the postop link below for more specific postop instructions.