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 decreases the ability of the corner of the mouth to turn up in a smile, creating asymmetry with smiling. One option is to treat this muscle an injection of Botox to weaken it in order to improve a patient’s smile.
Sometimes, resection of the DAO muscle will provide patients with a better smile than that which is achieved with Botox. Additionally, resection of the muscle is permanent unlike Botox which has to be re-administered every 3-4 months. Resection of this muscle is very straightforward, and there is almost no downside.
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 two weeks, patients are encouraged to begin a little gentle scar tissue massage to the area to expedite resolution of the swellng. We do ask that patients refrain from any exercise for 10 days after the procedure, but normal showering/hair washing is totally okay.