Skip to main content

The depressor labii inferioris (DLI) muscles move the lower lip downward to show the bottom teeth during smiling. Often, patients with facial paralysis have too much activity in this muscle on the unaffected side of their face. This hyperactivity creates a lower lip asymmetry when patients smile and talk, since the healthy side lower lip moves down but the side with paralysis does not. By weakening the healthy DLI muscle, we improve facial symmetry when patients smile, talk, and make other expressions. There are two ways we can weaken the DLI muscle:

  • Inject Botox to temporarily weaken the muscle (typically lasts 3-6 months)
  • Surgically remove the muscle to provide permanent lower lip symmetry

What to expect during DLI Excision procedure:

Surgical resection of the DLI muscle is typically performed in clinic under local anesthesia. A small incision is made inside the mouth (this is a scarless surgery) and the entire procedure takes 20-30. There are very few risks with the procedure.

After the procedure, patients can eat and drink normally once the numbing medication wears off (about an hour). The final effect of the DLI resection can be appreciated almost immediately once the swelling has gone down (usually only a few days of swelling).

If you would like to schedule a consultation at the UNC Facial Nerve Center, please call 984-974-2255.

Patient with facial paralysis before and after
Patient with right facial paralysis from trauma before (left) and after (right) DAO and DLI excision.
Bell's Palsy Patient before and after
Patient with right Bell’s palsy before (left) and after (right) DAO excision and DLI Botox.
DLI Botox and DAO Excision patient
Patient with right Bell’s palsy before (left) and after (right) DLI Botox and DAO excision.

Before and after - Improved Lower Lip Symmetry after Botox to right DLI Muscle