What is Maxillomandibular Advancement (MMA)?
Maxillomandibular advancement (MMA) moves the upper and lower jaws forward together, rotated about a planned center, so the airway holds open during sleep. It is among the most effective surgeries for obstructive sleep apnea, built on the Stanford protocol of Dr. Robert Riley and Dr. Nelson Powell.
The muscles of the throat hang from the bones of the face. Think of a tent: the jaws are the poles and the airway is the fabric. Move the poles forward and the fabric pulls tight, so it no longer sags inward when you sleep. This is why MMA works at several levels of the airway at once.
Before surgery
- A planning visit with a CT scan and a digital scan of your bite, used for virtual surgical planning.
- Stop aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve), fish oil, vitamin E and other supplements that thin the blood 7 days before surgery.
- If a doctor prescribed a blood thinner, do not stop it on your own. We will coordinate with that doctor.
- Plan for a hospital stay, and for an adult to help you at home during the first week.
After surgery
- There is no splint. Light rubber bands guide the bite, so you can still breathe through your mouth while your nose is congested.
- Swelling peaks in the first few days and settles over several weeks.
- Expect a liquid diet, then a soft diet, for several weeks.
- Numbness of the lower lip and chin is common and usually improves over months.
- At six to eight weeks, the support wires are removed and a sleep endoscopy checks your airway.
- A sleep study is repeated 10 to 12 months after surgery.
Call us right away if
- Bleeding from the mouth or nose does not slow with gentle pressure.
- You have a fever above 101°F (38.3°C).
- Swelling keeps increasing after the third day, or an incision drains pus.
For an emergency or any trouble breathing, call 911.
In a meta-analysis of 627 patients, major complications after MMA occurred in 1.0% and minor complications in 3.1%. We review your own risks with you before surgery, since they depend on your anatomy and health.
- Numbness
- The lower lip, chin, upper gums or teeth may feel numb. This usually improves over months and can persist in some patients.
- Change in the bite
- The bite is planned in advance and checked after surgery. Occasionally it needs further adjustment.
- Plates and screws
- They usually stay in place. About 15% are later removed.
- Change in the nose
- Planned and managed in the same operation. In a recent series, 6.5% later needed corrective nasal surgery.
- Bleeding
- Usually limited during surgery. Rarely, a transfusion or return to the operating room is needed.
- Infection
- Uncommon, and treated with antibiotics when it happens.
- Jaw joint discomfort
- Usually temporary as the bite settles.
- Anesthesia
- Risks of general anesthesia are reviewed with you by the anesthesia team.
Bite, Breathing & Beauty
The name says advancement.
Riley and Powell built maxillomandibular advancement around breathing. Over the past decade Dr. Liu has planned it for two more things at the same time: the bite it leaves behind, and the balance of the face. The jaws are not simply moved forward. They are rotated about a fixed center so all three improve together.
Bite
The upper and lower jaws move as one unit into a planned bite, so your teeth still meet correctly after surgery. In many cases this can be done surgery-first, which shortens the time spent in braces.
The maxillomandibular complex is rotated counterclockwise about a center at the maxillary buttress, keeping the first-molar level and preserving the designed occlusion. Surgery-first sequencing is practical when orthodontic leveling is limited.
Breathing
Advancing and rotating the jaws carries the tongue and palate forward and, just as important, restores tension to the airway muscles so the airway holds open during sleep.
Beyond enlarging the airway, MMA stabilizes the lateral pharyngeal wall and reverses concentric velar collapse on DISE. Airflow modeling shows reduced retropalatal velocity and downstream negative pressure, which track with AHI and ODI improvement.
Beauty
The jaws frame the lower face, so moving them in balance tends to strengthen the profile and chin. The changes to the face and nose are planned in advance, not left to chance.
The center of rotation is chosen to allow mandibular advancement without a protrusive midface, while septoplasty, turbinate reduction, piriformplasty, and an alar cinch manage the nose. Patient-reported nasal function and cosmesis improve with this approach.
How does maxillomandibular advancement work?
For years the benefit of jaw advancement was attributed to making more room behind the tongue. Our work showed the more important change happens at the soft palate and side walls of the throat. Using drug-induced sleep endoscopy before and after surgery, we found that the largest measurable effect of maxillomandibular advancement is a reduction in collapse of the velum and lateral pharyngeal walls.
A follow-up study using computational fluid dynamics confirmed it: the patients whose apnea improved the most were the ones whose lateral wall stability and airflow had normalized. This is one reason maxillomandibular advancement can help patients whose soft palate collapses in a complete concentric pattern, the same pattern that rules out hypoglossal nerve stimulation on its own.
As for the tongue, post-operative myofunctional therapy can be very helpful. For patients who still need more support, the combination of maxillomandibular advancement and hypoglossal nerve stimulation has shown reliability in treating sleep apnea. They work in complementary ways.
DISE before and after MMA
Dr. Liu was the first to describe changes in DISE before and after MMA surgery.
- 100% to 13%Lateral pharyngeal wall obstruction
- 56% to 0%Concentric collapse of the velum
- 19.3 to 6.6 m/sRetropalatal airflow velocity
Liu et al., J Oral Maxillofac Surg 2015 (DISE) and Otolaryngol Head Neck Surg 2016 (airflow modeling).
Virtual surgical planning
Typical counterclockwise rotation for a high angle, class 2 patient
- 1Maxillary cant, yaw, midline correction
- 2Rotation center decision for counterclockwise rotation (CCR)
- 3Advancement at the piriform rim
- 4Advancement at pogonion
MMA for referring physicians
MMA is not orthognathic surgery. Orthognathic surgery uses the facial skeleton to treat a skeletal problem, while MMA uses it to treat an airway problem. In the contemporary Stanford approach, the maxillomandibular complex rotates counterclockwise about a center at the maxillary buttress, and the plan is set by advancement at the piriform rim, change in the occlusal plane and the position of pogonion, rather than by SNA and SNB. With the first molar held level, about 3 to 5 mm of advancement at the piriform rim carries pogonion 12 to 18 mm forward, with the occlusal plane rotated about 6 to 10 degrees. Jaw movements follow the dentofacial phenotype: double-jaw advancement in class 2, counterclockwise rotation led by the maxilla in class 3, and surgery-first in class 1.
The maxilla is advanced in one piece. Segmental Le Fort I osteotomies leave the posterior maxilla, and the pharyngeal muscles attached to it, behind. When the maxilla is narrow, it is widened first with DOME and then advanced as a unit. Planning is done with the neck straightened, since the natural head position of a patient with OSA is often natural but not healthy. The nose is managed in the same operation with septoplasty, radiofrequency turbinate reduction with outfracture, piriformplasty, nasal floor contouring and an alar cinch.
There is no final splint, only light guiding elastics, so patients can breathe orally while the nose is congested. Suspension wires are removed at six to eight weeks with a repeat DISE, which documents the new collapse pattern. The sleep study is deferred to 10 to 12 months.
MMA and hypoglossal nerve stimulation treat different parts of the problem. Lateral wall and concentric velar collapse resolve after MMA and were not seen again 8 to 15 years later, so when relapse occurs it is almost always at the tongue base, the target of stimulation. In one patient, the AHI fell from 145 to 28 after MMA and to 3.2 after stimulation.
Dr. Liu's chapters on MMA and skeletal sleep surgery
Springer, 2023
Maxillofacial Surgery in OSA
The most technical of the chapters: reading the sleep study past the AHI, planning with the neck straightened, and mobilizing the maxilla by rocking it sideways rather than pulling it forward.
Read the chapter ›
Bailey's, 6th edition, 2022
Skeletal Surgery
Expansion, genioglossus advancement and MMA for trainees, organized around one idea: the airway muscles are only as stable as the bone they hang from.
Read the chapter ›
Maxillomandibular Advancement: Contemporary Approach at Stanford
Three decades of Stanford experience, written with Dr. Robert Riley as a step-by-step operation, with video. Rotation is centered at the maxillary buttress and the plan is set at the piriform rim, the occlusal plane and the chin.
Algorithm for Multilevel Treatment: The Riley, Powell, and Liu Stanford Experience
Written with both of his mentors, the bridge from the original Stanford protocol to the updated one. It sets out when jaw surgery should come first rather than last.
Sleep Surgery in the Era of Precision Medicine
Jaw movements follow the bite, and treatment success matters more than any single surgical number. Written with Dr. Robert Riley, Dr. Anthony Pogrel and Dr. Christian Guilleminault.
Considerations of Facial Skeletal Morphology to Optimize Upper Airway Stimulation
Sleep apnea can have a skeletal cause and a neuromuscular cause. MMA and stimulation treat each in turn, as in the patient whose AHI went from 145 to 28 to 3.2.
Contemporary Skeletal Surgery for Obstructive Sleep Apnea
Keep the upper jaw in one piece. Widen a narrow maxilla first with DOME, then advance it as a unit, so the airway muscles attached to it come forward too.
Advancements and Innovations in Sleep Surgery
The newer program in one place: rhinognathic surgery, minimally invasive DOME, two-incision stimulation and preservation pharyngoplasty, alongside buttress-centered MMA.
Related Research by Dr. Liu
Deeper sleep after MMA
In 10 patients with complete sleep studies before and after MMA, time awake after falling asleep dropped from 64 to 22 minutes and dream (REM) sleep increased. After surgery, sleep stages matched a population control group, with even less time awake during the night.
Protecting the nose
With the nose built into the operation, corrective nasal surgery after MMA fell from 18.7% to 6.5% (8 of 122 patients). In a later prospective group of 31, nasal breathing and nasal appearance scores both improved after surgery.
It works for both kinds of bite
In matched groups of 14 patients with a class 2 bite and 14 with a class 3 bite, AHI fell from 43.4 to 9.6 and from 37.2 to 11.8. Patients with a class 3 bite gained less nasal breathing, so their nose is planned for up front.
MMA can make Inspire possible
Eighteen patients who were first ineligible for Inspire had surgery such as MMA, DOME or palatopharyngoplasty, then stimulation. Their AHI fell from 49.3 to 3.5, compared with 33.4 to 5.3 in patients who qualified from the start.
MMA | Frequently asked questions
Who is a candidate for MMA?
CPAP or an oral appliance is optimized first. Dr. Liu considers MMA first in three situations:
- Obstructive sleep apnea of any severity together with a dentofacial deformity.
- Moderate to severe obstructive sleep apnea, with or without prior palate or nasal surgery.
- Complete concentric collapse of the soft palate together with complete collapse of the side walls of the throat on DISE, the pattern that rules out hypoglossal nerve stimulation.
A normal jaw position does not rule a patient out.
How effective is MMA?
In a meta-analysis of 627 patients (Holty and Guilleminault), MMA lowered the apnea-hypopnea index (AHI) from 63.9 to 9.5 events per hour. Surgical success was 86.0% and “cure” (AHI below 5) was 43.2%, with major complications in 1.0%.
In matched Stanford cohorts, success was 92.8% in patients with class 2 and 78.6% in patients with class 3 dentofacial deformity.
Will MMA change my nose and face?
Yes, and the changes are planned rather than left to chance. Advancing the upper jaw moves the base of the nose, so the nose is managed in the same operation through septoplasty, turbinate reduction, piriformplasty, and an alar cinch.
With this comprehensive nasal strategy, the need for later corrective nasal surgery fell from 18.7% (379 patients) to 6.5% (122 patients), and patients reported better nasal breathing and nasal appearance after surgery.
Can MMA be combined with Inspire?
Yes. MMA stabilizes the soft palate and the side walls of the throat, while hypoglossal nerve stimulation (Inspire) moves the tongue base. Dr. Liu and Dr. Robert Riley reported the first successful case of stimulation after MMA.
Patients who were not candidates for stimulation at first (AHI above 65, BMI above 32, or concentric collapse) and had multilevel surgery including MMA, then stimulation, reached a mean AHI of 3.5, down from 49.3 (J Oral Maxillofac Surg 2023).