MMA surgery, short for maxillomandibular advancement, is a procedure that moves both the upper and lower jaw forward to open the airway behind the throat. It is primarily used to treat obstructive sleep apnea, particularly in people who cannot tolerate or don’t get enough relief from a CPAP machine. By physically enlarging the space air passes through during sleep, MMA addresses the structural root of airway collapse rather than just managing symptoms.
How MMA Surgery Opens the Airway
During sleep apnea, the soft tissues at the back of the throat relax and collapse inward, blocking airflow. MMA surgery works by advancing the entire bony framework that supports those tissues. When the upper jaw (maxilla) and lower jaw (mandible) are moved forward, the tongue, soft palate, and surrounding muscles come with them, creating a wider and more stable airway.
Surgeons typically advance the jaws by 6 to 10 millimeters or more. Cadaveric research published in the International Journal of Oral and Maxillofacial Surgery found that even 6 to 8 millimeters of advancement produces substantial increases in airway volume. Some surgeons aim for at least 10 millimeters of mandibular advancement, and evidence suggests that greater than 10 millimeters of maxillary advancement is associated with higher surgical success rates. The exact distance depends on your anatomy and severity of apnea.
Who Is a Candidate
MMA surgery is generally considered for people with moderate to severe obstructive sleep apnea who have tried and failed other treatments, most commonly CPAP therapy. Some people cannot wear a CPAP mask consistently due to discomfort, claustrophobia, or skin irritation. Others find that oral appliances or less invasive surgeries (like removing tonsils or trimming the soft palate) haven’t resolved their symptoms.
Younger patients with a noticeably set-back jaw or small midface are often strong candidates because their anatomy directly contributes to the airway obstruction. MMA can also be appropriate for people with significant facial skeletal imbalances that affect both breathing and bite alignment, making it a functional and cosmetic correction at the same time.
What the Surgery Involves
MMA is a major operation performed under general anesthesia, typically lasting several hours. It combines two well-established bone-cutting techniques. The upper jaw is repositioned using a procedure called a Le Fort I osteotomy, where the surgeon makes a horizontal cut across the maxilla above the roots of the upper teeth, then moves the entire upper jaw forward and secures it with small titanium plates and screws. The lower jaw is repositioned using a bilateral sagittal split osteotomy, which involves splitting the jawbone on each side near the back molars and sliding the front portion forward.
All incisions are made inside the mouth, so there are no visible scars on the face. Once both jaws are in their new positions, the surgeon fixes them in place with titanium hardware that stays permanently. The bite is carefully planned beforehand so the teeth come together properly after advancement.
Orthodontic Preparation and Timeline
Most people need braces or aligners before and after MMA surgery to ensure the teeth fit together correctly once the jaws are repositioned. This pre-surgical orthodontic phase typically lasts 12 to 24 months, with a median of about 17 months. The goal is to align the teeth within each jaw so that when the surgeon moves the bones, the upper and lower teeth mesh properly.
After surgery, a second phase of orthodontic treatment begins about two weeks post-op and lasts roughly 7 to 12 months to fine-tune the bite. In total, the complete process from starting braces to finishing post-surgical orthodontics can span two to three years. Some surgical teams now use a “surgery first” approach that shortens or eliminates pre-surgical orthodontics, but this isn’t suitable for every patient.
Success Rates
MMA is one of the most effective surgical treatments for obstructive sleep apnea. In a retrospective study of 100 patients, 67% achieved a favorable surgical response, defined as at least a 50% reduction in the number of breathing disruptions per hour of sleep, with the post-surgical count dropping below 20 events per hour. Many patients in successful cases see their numbers fall into the normal range (fewer than 5 events per hour), effectively curing their apnea.
Follow-up sleep studies are typically performed 6 to 12 weeks after surgery, then again at one and two years. Research tracking patients over two years found no significant decline in results between the early post-operative period and the two-year mark, suggesting the airway improvements are stable and lasting.
Recovery and What to Expect
Hospital stays after MMA surgery usually last one to three nights. The first two weeks are the most uncomfortable, with significant facial swelling, jaw stiffness, and difficulty eating. Most patients are placed on a liquid or very soft diet for four to six weeks while the bones heal. Swelling peaks around the third or fourth day and gradually improves over several weeks, though mild puffiness can linger for months.
You’ll likely need four to six weeks off work, depending on how physically demanding your job is. The jaws are not wired shut in most modern cases, but elastic bands are often placed on the braces to guide the bite during healing. Speaking is possible right after surgery, though it may feel awkward at first. Most people return to a normal diet and activity level by eight to twelve weeks.
Risks and Nerve Sensation Changes
The most common side effect of MMA surgery is altered sensation in the lower lip, chin, and gums. This happens because the nerve that runs through the lower jaw is stretched or bruised during the bone-splitting procedure. About 70% of patients experience some temporary numbness, and roughly one-third report a permanent change in sensation when assessed by how things feel to them subjectively. When measured at the individual nerve level, permanent altered sensation drops to about 20%.
For most people, “permanent” changes are subtle. You might notice that part of your lower lip feels slightly different when touched, or that your chin tingles occasionally. Complete loss of feeling is uncommon. The sensation often continues to improve gradually over 12 to 18 months after surgery.
Other potential risks include infection, bleeding, unwanted bite changes, relapse of the jaw position, and temporary jaw joint discomfort. Serious complications are rare when the surgery is performed by an experienced oral and maxillofacial surgeon or a surgical team that regularly handles these cases.
Facial Appearance After Surgery
Because MMA moves the entire midface and lower face forward, it changes your profile noticeably. Most people develop a fuller, more projected facial appearance. The cheekbones, upper lip area, and chin all shift forward. For patients who already had a recessed jaw, the result is often a more balanced, conventionally attractive profile. People with an already prominent midface may find the change less desirable, which is why surgical planning includes careful analysis of facial proportions.
Surgeons use 3D imaging and sometimes printed models to plan the exact movement in all three dimensions, controlling not just how far forward the jaws move but also any vertical or side-to-side adjustments. Counter-clockwise rotation of the jaw complex is a common planning technique that maximizes airway opening while producing a favorable cosmetic outcome.