Download Maxillomandibular advancement for obstructive sleep apnea

Operative Techniques in Otolaryngology (2012) 23, 60-66
Maxillomandibular advancement for obstructive sleep
apnea syndrome
Marc B. Blumen, MD,a Jean Philippe Vezina, MD, FRCSC,a Jean Luc Pigot, MD,b
Frédéric Chabolle, MDa
From the aENT and Head Neck Department, Foch Hospital, Suresnes, France; and the
b
Oral Surgery Department, Foch Hospital, Suresnes, France.
KEYWORDS
Sleep apnea;
Surgery;
Bony structures;
Maxillomandibular
advancement
Maxillomandibular advancement enlarges the entire pharynx by pulling anteriorly the bony squelettal
structures. It is performed in sleep apnea patients who refuse or fail to use continuous positive airway
pressure. It is constantly associated to esthetic modifications but not necessarily disgraceful. Perioperative breathing complications can occur which implies a good cooperation between the surgeon and
the anesthesiologists in the operating room and in the following hours in the ICU. Hypoesthesia of the
lower lip and chin is the most frequent long term complication. Nevertheless, bimaxillary advancement
is one of the most effective treatments for OSAS even on a long term basis.
© 2012 Elsevier Inc. All rights reserved.
Obstructive sleep apnea syndrome (OSAS) affects 2-4%
of the general population. Because it is associated with
cardiovascular and metabolic complications, it requires a
good management and an appropriate follow-up. Several
pathophysiological factors are noted. One of them is often
mentioned: the imbalance between the maxillofacial bony
structures (“squelettal box”) and the pharyngeal soft tissue
volume/compliance.
Numerous surgical techniques have been developed by
otolaryngologists to reduce the soft tissue volume or to put
tension on these structures, whether directly or indirectly by
reinserting them in a more forward position. Because they
are performed by otolaryngologists who are first-line managers of patients with OSAS, these techniques are generally
the first used.
The bony structures can also be malformed. The maxilla
and mandible are sometimes abnormally narrow transversely. They can also be positioned backward relative to
the skull base. Bimaxillary advancement surgery increases
the volume of the “squelettal box” of the face and thus
corrects the mismatch between the soft tissues and their
Address reprint requests and correspondence: Marc B. Blumen,
MD, ENT and Head Neck Department, Hospital Foch, 40 rue Worth,
92150 Suresnes, France.
E-mail address: [email protected].
1043-1810/$ -see front matter © 2012 Elsevier Inc. All rights reserved.
doi:10.1016/j.otot.2011.11.011
container. The surgical technique used for OSAS is the
same as for orthognathic surgery. However, it is less commonly performed than soft tissue surgery because it is more
complex and more often performed by maxillofacial surgeons who have generally less contact with OSAS.
Surgical technique
Preoperative workup
A complete workup including the following items is
required before bimaxillary advancement surgery:
●
●
●
Facial photographs are taken for esthetic comparison purposes.
A lateral skull radiograph is performed for cephalometric
analysis to quantify the degree of maxillomandibular insufficiency and to plan the advancement needed.
To allow the appropriate mandibular advancement, it is
necessary to create an interim splint (see surgical technique).
Dental casts are produced and mounted on a semiadjustable
articulator to provide an exact assessment of the anatomic
position of the maxilla and the mandible. A model plateform
is used to simulate the planned movements of the 2 bones.
Blumen et al
Maxillomandibular Advancement for OSAS
61
Figure 1 (A) Mandibular osteotomy. Preparation of the split: Drawing of the cut with a burr at the level of the second premolar. (B)
Sagittal split. The integrity of the alveolar nerve is checked.
Then the interim splint is created using the advanced mandibular cast referenced to the uncut mounted maxillary cast.
It will be disinfected before the intervention and will be
available to the surgeon when the time comes.
If the day before surgery dental arch bars are put in place
under local anesthesia, the procedure can be shortened. The
arches will allow intermaxillary fixation at the end of the
procedure or several days after.
Operative technique
Bimaxillary advancement surgery combines 2 different procedures: a bilateral sagittal split of the mandible followed by
a Le Fort I maxillary osteotomy under general anesthesia.
Sagittal split of the mandible (technique of
Obwegeser–Dalpont)
Preparation for the split
The lateral aspect of the mandibular body, the retromolar
triangle, and the inner portion of the ramus are infiltrated
with xylocaine/epinephrine in the submucosal and subperiosteal planes. A bite block and a tongue depressor are used
to expose the operative field.
The incision is carried out directly to the periosteum with
a cold blade, starting at the level of the first premolar
anteriorly and curving medially on the retromolar trigone
posteriorly. On the anterior portion, care is taken to keep
about 1 cm of unattached mucosa laterally to the gum to
facilitate wound closure.
The subperiosteal plane is dissected with a periosteal
elevator, anteriorly to expose the mental nerve and inferiorly to show the inferior border of the mandible. Superiorly,
the anterior portion of the ascending ramus is exposed, and
the lower temporalis muscle fibers are cut up to the coronoid
process. Medially, the periosteum is raised to show the
mandibular foramen and the lingula (spine of Spyx).
Pledgets soaked with an epinephrine solution can be placed
in that space to reduce bleeding.
A 2-mm cutting burr is used to cut the outer cortex of the
mandibular bone vertically at the level of a region between
the first and second premolar depending on the planned
advancement (Figure 1A). The cut must extend to the lowest
part of the bone and should not be too deep to prevent
alveolar nerve damage. Starting at the top of this cut, a
dotted line is drilled through the upper cortex of the mandible, laterally to the molars on the anterior part and in the
middle of the retromolar triangle posteriorly. A second
vertical cut is then made on the inner cortex of the ascending ramus, posterior to the lingula. A Lindeman burr is used
to make a continuous cut through the dotted line, and this
cut is slightly enlarged with a large caliber burr to facilitate
the insertion of the osteotomes.
Split
Various osteotomes are used to perform the split. At first
very thin, their size is gradually increased. Curved osteotomes are used anteriorly. They are directed toward the
outer cortex to keep the alveolar nerve in contact with the
medial cortex. A separator is positioned on the inferior
border cut to apply a constant split pressure. The split is
performed carefully and gradually, using slight torsion
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Figure 2 (A, B) Placement of the intermediate splint. Once the sagittal split is performed, the mandible is pulled forward, and the
intermediate splint is placed over the teeth and is maintained with 4/0 wires.
movements and driving the osteotomes deeper until the
fragments are properly separated.
After the split is performed, the position of the alveolar
nerve is verified. If needed, it is dissected from the proximal
fragment to protect it during the advancement (Figure 1B).
The same procedure is performed on the opposite side.
Advancement and fixation
A traction wire is passed around the 4 inferior incisors.
The mandible is advanced, and the teeth are positioned over
the intermediate interdental splint. The occlusion is fixed in
that position using four 4/10 metal wires secured on the arch
bars (Figure 2).
Rigid fixation of the fragments is performed using 1
adjustable miniplate at the level of the anterior vertical cut
on each side. The posterior fragment is pulled through the
incision using forceps, and the nonadjustable side of the
plate is fixed to its distal end (Figure 3). The plated proximal
fragment is pushed back to its original position. The advancement is performed using a distractor and measured
using a caliper. For obstructive sleep apnea, 10 mm at least
is usually necessary (Figure 3). Two millimeters should be
added to the planned advancement to account for the width
of the cut itself. The lower border of both fragments should
be aligned, and no gap should be left. The plaque can be
bent to ensure good contact. The first screw is placed in the
adjustable hole, and the advancement is measured a second
time before securing it. The other screws are placed there-
after. Care must be taken to protect the mental nerve during
this step.
Once rigid fixation is done on both sides, bicortical
screws are placed on both mandibular angles using a transjugal approach (Figure 3). After the screws are tightened, it
is important to make sure they involve both cortices by
gently trying to pull them apart.
Le Fort I maxillary osteotomies and advancement
Preparation for osteotomies
The subperiosteal plane of the upper gingivobuccal sulcus is infiltrated with xylocaine/epinephrine. The incision is
carried out directly to the periosteum using a cold blade,
from 1 first molar to the other. A 1-cm cuff of unattached
gingival mucosa is kept to facilitate wound closure. At the
level of the frenulum of the upper lip, a v-shaped incision is
made.
A periosteal elevator is used to dissect the subperiosteal
plane, posteriorly as far as the maxillary tuberosity, superiorly to show the infraorbital pedicle, medially to uncover
the border of the piriform aperture, and inferiorly to expose
the imprints of the dental roots. The anterior nasal spine
should also be completely released. Pledgets soaked with
epinephrine can be placed posterior to the maxillary tuberosity to reduce venous bleeding. The mucosa of the floor of
the nasal fossae is raised using a curved elevator for the first
2-3 cm and a straight elevator for the posterior part. The
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Maxillomandibular Advancement for OSAS
63
lower septum and lateral nasal walls are also dissected using
a torsion movement of the elevator. Constant bony contact
is important to avoid mucosal tears. Soaked pledgets can
also be left in this space.
Le fort I osteotomies
Retractors are placed to protect the nasal mucosa and
lateral soft tissues. A reciprocating saw is used to cut the
anterior part of the maxillary bone, starting at the zygomaticomaxillary buttress up to the lateral nasal wall (Figure 4).
The cuts should be symmetrical on both sides and away
from the dental roots.
The pterygoid plates are separated from the maxillary
bone. This step is best performed with a manual osteotome.
The lateral nasal walls and the posterior part of the maxillary bone are cut with a thin osteotome. The cartilaginous
and bony nasal septum is freed from the nasal crest using a
U-shaped osteotome.
If a need for impaction was determined in the preoperative planning, a uniform slice of bone could be removed on
all osteotomies.
Advancement and fixation
Maxillomandibular fixation is released. A distractor is
used to verify the mobility of the lower fragment of the
maxillary bone. Any remaining attachment (especially at
the posterior aspect of the maxillary sinus) is cut. Forceps
Figure 3 Placement of the osteosynthesis plate. The posterior
fragment of the mandible is pulled through the incision with a
forceps. The nonadjustable side of the plate is fixed first. Osteosynthesis. The plate is fixed to ensure stability of the advancement
of at least 10 mm. Some authors may put in the gap cortical bone
harvested from the parietal bone. Osteosynthesis of the posterior
fragments. Through a transjugal approach, a bicortical screw is
placed in the mandibular angle to bring closer the 2 mandibular
valves.
Figure 4 Maxillary osteotomy. After having reclined the muscles and periosteum of the anterior aspect of the maxillar and the
malar bone as well as the nasal cavity mucosa, anterior osteotomies are performed through the maxillar and zygomaticomaxillary
buttress.
are then used to mobilize the fragment (Figure 5). The
movements must be unrestricted in all directions. Gradual
anterior traction allows muscle stretching in preparation for
fixation. The superior dental arch should reach its final
position without excessive tension.
The final interdental splint is positioned, and occlusion is
obtained. Maxillomandibular fixation is performed using
Figure 5
ceps.
Maxillary dysjunction using Rowe and Quiles for-
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elevated blood pressure (which might remain undiagnosed
because it occurs during the night), coronary artery disease,
cardiac arrhythmia, neurovascular disease, and diabetes. To
avoid postoperative complications, all these factors need to
be assessed and properly managed before surgery.
Orthodontic considerations
Figure 6 Zygomaticomaxillary buttress osteosynthesis using
wires to avoid posterior open bite. Maxillary fixation with miniplates.
four 4/10 metal wires. Anterior traction can be aided with a
metal wire passed around the incisors, similar to the technique described for the mandible.
Before rigid fixation is performed, burr holes are made
through the zygomaticomaxillary buttresses on the upper
and lower fragments, and 4/10 metal wires are passed
through them. They are left untightened at this stage (Figure
6). They will help prevent posterior open bite.
Rigid fixation is performed using 1 preformed miniplate
on each side. The plates must clear the infraorbital foramen
and dental roots. The plates are first secured to the lower
fragment with 5-mm screws and then to the upper fragment
after fine-tuning (Figure 6).
The posterior metal wires are tightened, and maxillomandibular fixation is removed.
Surgical field is cleaned with saline. All wounds are
closed using absorbable sutures. A VY suture is performed
on the maxillar mucosa on the midline. Blocks of the infraorbital and mental nerves are performed using bupivacaine.
The intermaxillar fixation is secured either at the end of
the surgical procedure or 1 or 2 days after and is left in place
for 3-4 weeks. A liquid diet is prescribed for ⬎4 weeks.
Dental and gum hygiene are mandatory for that period.
Differences with orthognathic surgery
The OSAS patient
The typical OSAS patient is middle aged, obese, and has
significant comorbid medical conditions. He/she has a high
potential cardiovascular morbidity with a higher risk for
One-third of OSAS patients show craniofacial abnormalities, with a predominance of dental malocclusion class II.
In such a case, correcting the malformation itself in addition
to improving sleep apnea appears logical. This might require an orthodontic preparation that could last between 12
and 18 months. However, this is seldom performed for
several reasons. First, the patient who undergoes bimaxillary advancement usually has severe OSAS and has failed
most available treatments. If continuous positive airway
pressure (CPAP) therapy is not possible, the potential cardiovascular complications and the cognitive impairments
related to the disease (sleepiness, irritability, memory loss,
and concentration difficulties) usually preclude waiting such
a long time before surgery. Second, the teeth and gums in
middle-aged patients are not always healthy enough to bear
an orthodontic therapy. Third, the patient’s primary concern
is not esthetics. Finally, the cost of such treatment is generally high and is rarely reimbursed by our medical system.
For all these reasons, the preoperative relationship between
the maxilla and the mandible is maintained for most patients.
Perioperative anesthetic management
Perioperative anesthetic management is of high importance. A preoperative consultation is mandatory to determine the risk of cardiovascular morbidity during the procedure. The preoperative consultation helps screen for
cardiovascular risk factors that should be controlled before
surgery, especially hypertension and high blood glucose
levels for diabetic patients. The expected difficulty of intubation and risk of aspiration must be properly appreciated,
as patients with a Mallampati grade 3 or 4 have a 20% risk
of difficult intubation.
A fiberscope must be present in the operating room and
will be used if there is the slightest difficulty for intubation.
An arterial catheter will be positioned to measure blood
pressure. A BIS may be used to monitor the depth of
anesthesia.
Preoxygenation using a facial mask will be performed
before intubation. Nasotracheal intubation is used, which
may be accomplished either under local anesthesia or under
sedation (using a fast-action nondepolarizing curare and
hypnotics). The endotracheal tube is secured to the columella with a suture.
During the procedure, arterial blood pressure must be
controlled. The concentrations of anesthetic drugs will be
decreased in advance to allow awakening to coincide with
the end of the intervention. The extubation should be conducted on the operating room table. Antibiotics, anti-inflam-
Blumen et al
Maxillomandibular Advancement for OSAS
matory drugs, and analgesics will be prescribed for the
postoperative period.
The postoperative period needs to be carried out in an
intensive care unit for 24 hours. The patient will be in a
semiseated position. Oxygen supplementation is administered if necessary. Aspiration of the nasal cavity should be
performed. Control of blood pressure and pain is essential to
avoid postoperative bleeding. Ice packs will be placed on
the patient’s cheeks. Some authors advocate CPAP use
during the postoperative period to prevent the occurrence of
apneas caused by swelling and hematomas secondary to the
surgical procedure. However, it is not always easy to use
because the patient did not initially support CPAP and
because the nasal cavities are full of blood and secretions.
Degree of advancement
The minimal effective advancement is impossible to determine beforehand. Some have proposed to use the same
advancement as needed for an effective oral appliance.1
However, oral appliances do not advance the mandible in
the same plane as surgery does and do not displace the
maxilla. Given the importance of the intervention, most
authors suggest to achieve maximum advancement, ie, to
normalize the cephalometric measurements on a lateral xray and to produce a minimum advancement of 10 mm at
the level of the mandible. The length of mandibular advancement usually varies from 10 to 12 mm. Maxillary
advancement is the same or less (5-10 mm)2-5 taking into
account that the mandible does a counterclockwise rotation
during the advancement.
Combined surgical procedures
Three types of surgical procedures can be performed
concurrently to bimaxillary advancement.
Upper airway impairment from edema or a hematoma
can result from bimaxillary advancement surgery.6 Few
authors perform a preventive tracheostomy to help the patient breath and facilitate aspiration of the secretions in the
immediate postoperative period.7 Tracheostomy is temporary and removed after a few days.
Procedures that can improve the efficiency of maxillomandibular advancement can also be performed, especially
if there is a specific complaint such as nasal obstruction. In
this case, a septoplasty and/or lower turbinectomy may be
carried out8 even if bimaxillary advancement often spontaneously improves nasal breathing. Other authors have performed a genioglossus advancement using a genioplasty9 or
a maxillary distraction osteogenesis and more rarely a mandibular symphyseal distraction osteogenesis.10
Finally, some procedures allow for some modifications
of the patient’s esthetics. They can correct some adverse
esthetic effects resulting from a large advancement in a
patient with a normal preoperative cephalometric analysis.11
They can also further advance a patient’s chin position if it
was retruded before surgery.
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Indications– contraindications
Bimaxillary advancement surgery is indicated in a patient with severe sleep apnea syndrome or moderate OSAS
with severe daytime sleepiness. The patient must have failed
to use of CPAP or/and an oral appliance. Some authors
advocate its use after treatment of the pharyngeal soft tissues (phase II of Stanford),12 and others perform it in the
first place in the presence (or absence) of skeletal bone
abnormalities.13,14
Contraindications can be related to either general or local
factors. Age of the patient (⬎65 years old), an unstable
cardiovascular status, and for some,5 but not for all,15 obesity preclude the use of this therapy. The presence of central
sleep apnea syndrome16 and alveolar hypoventilation are
elements that explain some cases of failure of this surgery.
Poor teeth and gum status increase the risk of infectious
problems. A massive edentulous state makes surgery more
difficult.
Results
Bimaxillary advancement is the most effective and definitive treatment among all therapeutic options (outside of
tracheostomy) for sleep apnea syndrome. It is effective on
clinical symptoms such as snoring, daytime sleepiness,16
and quality of life.17 It is also effective on objective polysomnographic elements—ventilation and sleep. Short-term
success rates range from 80 to 100% when success is defined as an apnea– hypopnea index ⬍20 and a reduction of
more than 50% of the preoperative index.12-14
A meta-analysis comprising 22 studies evaluated 627
patients. Cure (defined as an apnea– hypopnea index ⬍5
events/hr of sleep) was obtained in 43.2% of the cases.18
Mean apnea– hypopnea index decreased from 63.9 ⫾ 26.7
to 9.7 ⫾ 1 0.7 hours. The effectiveness of the procedure has
been found to be comparable with that of mechanical ventilation.7,16,19 It remains effective in the long-term (more
than 24 months) in the absence of weight gain.20,21 The
predictors of surgical success are a younger age, a lower
BMI, a lower AHI, and a larger maxillary advancement.18
Side effects and complications
Functional side effects
The most frequently reported complication is hypoesthesia of the lower lip and chin, which is constant in the
immediate postoperative period but may be permanent in
11-86% of cases.22 Masticatory apparatus disorders can also
be observed.23
Esthetic
Cosmetic changes are noticed by most of the patients and
their family.23,24 There is an enlargement of the nostrils, an
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opening of the nasolabial angle, a widening of the lower
face,23 and a prognathism for patients with a normal preoperative maxillomandibular complex position.24 The procedure, however, is regarded as unsatisfactory by only 5.2% of
the patients.23
Complications
Complications are rare. Bleeding requiring surgery
(1.3%), swelling, hematoma (20% of cases),6 superinfection, and pseudarthrosis are rather rare.23 No deaths have
been reported.18
Conclusions
Maxillomandibular advancement is one of the most effective therapeutic options for treating patients with severe
sleep apnea syndrome who fail to respond to other treatments such as CPAP or oral appliance. Informed consent
should be obtained from these patients, especially if they are
young. Frank and clear information about not only the
effectiveness of this procedure but also its potential functional and esthetic side effects should be given. Finally, it
requires trained surgical and anesthetic teams to operate in
a safe environment, to limit the perioperative risks, and to
perform a large and stable advancement.
References
1. Hoekema A, de Lange J, Stegenga B, et al: Oral appliances and
maxillomandibular advancement surgery: An alternative treatment
protocol for the obstructive sleep apnea-hypopnea syndrome. J Oral
Maxillofac Surg 64:886-891, 2006
2. Waite PD, Wooten V, Lachner J, et al: Maxillomandibular advancement surgery in 23 patients with obstructive sleep apnea syndrome.
J Oral Maxillofac Surg 47:1256-1261, 1989; discussion 62
3. Riley RW, Powell NB, Guilleminault C: Maxillofacial surgery and
obstructive sleep apnea: A review of 80 patients. Otolaryngol Head
Neck Surg 101:353-361, 1989
4. Wagner I, Coiffier T, Sequert C, et al: Surgical treatment of severe
sleep apnea syndrome by maxillomandibular advancing or mental
tranposition [in French]. Ann Otolaryngol Chir Cervicofac 117:137146, 2000
5. Smatt Y, Ferri J: Retrospective study of 18 patients treated by maxillomandibular advancement with adjunctive procedures for obstructive
sleep apnea syndrome. J Craniofac Surg 16:770-777, 2005
6. Li KK, Riley RW, Powell NB, et al: Postoperative airway findings
after maxillomandibular advancement for obstructive sleep apnea syndrome. Laryngoscope 110:325-327, 2000
7. Vicini C, Dallan I, Campanini A, et al: Surgery vs ventilation in adult
severe obstructive sleep apnea syndrome. Am J Otolaryngol 31:14-20,
2010
8. Ronchi P, Novelli G, Colombo L, et al: Effectiveness of maxillomandibular advancement in obstructive sleep apnea patients with and
without skeletal anomalies. Int J Oral Maxillofac Surg 39:541-547,
2010
9. Prinsell JR: Maxillomandibular advancement surgery for obstructive
sleep apnea syndrome. J Am Dent Assoc 133:1489-1497, 2002; quiz
539-540
10. Boyd SB: Management of obstructive sleep apnea by maxillomandibular advancement. Oral Maxillofac Surg Clin North Am 21:447-457,
2009
11. Bruno Carlo B, Mauro P, Silvia B, et al: Modified genioplasty and
bimaxillary advancement for treating obstructive sleep apnea syndrome. J Oral Maxillofac Surg 66:1971-1974, 2008
12. Riley RW, Powell NB, Guilleminault C: Obstructive sleep apnea
syndrome: A review of 306 consecutively treated surgical patients.
Otolaryngol Head Neck Surg 108:117-125, 1993
13. Prinsell JR: Maxillomandibular advancement surgery in a site-specific
treatment approach for obstructive sleep apnea in 50 consecutive
patients. Chest 116:1519-1529, 1999
14. Hochban W, Brandenburg U, Peter JH: Surgical treatment of obstructive sleep apnea by maxillomandibular advancement. Sleep 17:624629, 1994
15. Li KK, Powell NB, Riley RW, et al: Morbidly obese patients with
severe obstructive sleep apnea: Is airway reconstructive surgery a
viable treatment option? Laryngoscope 110:982-987, 2000
16. Conradt R, Hochban W, Heitmann J, et al: Sleep fragmentation and
daytime vigilance in patients with OSA treated by surgical maxillomandibular advancement compared to CPAP therapy. J Sleep Res
7:217-223, 1998
17. Lye KW, Waite PD, Meara D, et al: Quality of life evaluation of
maxillomandibular advancement surgery for treatment of obstructive
sleep apnea. J Oral Maxillofac Surg 66:968-972, 2008
18. Holty JE, Guilleminault C: Maxillomandibular advancement for the
treatment of obstructive sleep apnea: a systematic review and metaanalysis. Sleep Med Rev 14:287-297, 2010
19. Hochban W, Conradt R, Brandenburg U, et al: Surgical maxillofacial
treatment of obstructive sleep apnea. Plast Reconstr Surg 99:619-626,
1997; discussion 27-28
20. Li KK, Powell NB, Riley RW, et al: Long-term results of maxillomandibular advancement surgery. Sleep Breath 4:137-140, 2000
21. Conradt R, Hochban W, Brandenburg U, et al: Long-term follow-up
after surgical treatment of obstructive sleep apnoea by maxillomandibular advancement. Eur Respir J 10:123-128, 1997
22. Al-Bishri A, Rosenquist J, Sunzel B: On neurosensory disturbance
after sagittal split osteotomy. J Oral Maxillofac Surg 62:1472-1476,
2004
23. Blumen MB, Buchet I, Meulien P, et al: Complications/adverse effects
of maxillomandibular advancement for the treatment of OSA in regard
to outcome. Otolaryngol Head Neck Surg 141:591-597, 2009
24. Li KK, Riley RW, Powell NB, et al: Patient’s perception of the facial
appearance after maxillomandibular advancement for obstructive sleep
apnea syndrome. J Oral Maxillofac Surg 59:377-380, 2001; discussion
80-81