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Fig. 29.4 Genioglossus advancement (GA). Improvement of the airway collapse at the level of
the tongue base is seen with a mild modication of the chin area that has been displaced anteriorly
at the level of insertion of the genioglossus muscle
S. Y.-C. Liu and K. Schwartz
29.2.2 Indications
Isolated GA, or combined with a genioplasty (GGA), is typically one component of
multilevel sleep surgery for OSA.The primary indication for GA is airway obstruction at the hypopharyngeal level, especially in conjunction with a retruded position
of the tongue base, in the absence of lingual tonsillar hypertrophy. OSA patients
with mandibular retrognathism and microgenia will benet from GA in combination with a genioplasty (GGA), as it addresses hypopharyngeal obstruction and dentofacial deformity (Fig.29.4).
29.2.3 Surgical Technique
GA is performed under general anesthesia. A reinforced oral endotracheal tube is
secured to either lip commissure allows adequate exposure of the surgical eld. A
vestibular incision is made 1.5 to 2.0cm from the mucogingival junction, through
the labial mucosa. At this point, the approach is perpendicular to the distended
lower lip. Once the mentalis muscles are identied, the approach takes an oblique
path toward the inferior border of the anterior mandible prior to subperiosteal dissection to access the bone. This detail during the approach is essential because,
without it, there would often be inadequate muscle and mucosal cuff to close with
the advanced bone graft.
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Subperiosteal dissection is extended bilaterally along the inferior border until the
mental nerve is identied on both sides. For an isolated GA (anterior mandibular
osteotomy) only, identication of the genial tubercle can be made by palpating the
oor of the mouth or measuring its position from the preoperative CT. However,
with a preoperative CT scan, a 3-dimensional (3D) cutting guides can be made to
direct osteotomy toward the exact location of the genial tubercle. A rectangular
osteotomy is made through the outer cortex. The osteotomy is typically 10mm by
20mm and the superior osteotomy should be places a least 5mm inferior to the root
apices. To avoid mandibular fracture, the inferior osteotomy should be approximately 8mm above the inferior border of the mandible. A bicortical screw is placed
though the center of the rectangular osteotomy to allow manipulation of the bone
fragment. The osteotomy cuts are then completed through the inner cortex.
Maintaining parallel walls in the osteotomy cuts is important to prevent tapering on
the inner cortex. By grasping the bicortical screw, the bone fragment can be gently
advanced and rotated 90 degrees in either direction. The outer cortex and bone marrow is removed with a round cutting bur or electric piezo saw, and the fragment is
xated with a titanium screw at the inferior border. A round or pear-shaped cutting
burr may be used to contour the advanced bone fragment.
For a genioglossus and genioplasty advancement (GGA) the osteotomy includes
both the genial tubercle and the inferior border of the mandible. This is particularly
useful in patients with mandibular retrognathism and low hyoid position or in
patients with insufcient chin length for an isolated GA. Osteotomy guides and
patient specic implants (PSI) can be designed by virtual-surgical-planning (VSP)
and used intraoperatively to ensure precise location of the genial tubercle, avoidance of vital structures and accuracy and stability in the surgical procedure. In cases
where the genial tubercles are in unfavorable positions, they should be avoided.
When genial tubercles are superior and close to the dentoalveolar bone, capturing
them would increase risk of dentoalveolar fracture. As stated earlier, the genioplasty
advancement can still address dentofacial deformity, decrease possible mentalis
strain, and still provide tension for the suprahyoid muscles (Fig.29.5).
Sufcient hemostasis should be ensured before wound closure. Inadvertent
injury to the sublingual artery and veins can easily occur with a reciprocating saw
and lead to the formation of a postoperative sublingual hematoma. The surgical
incision is closed in two layers with a suspension of the mentalist muscle with horizontal mattress sutures and by closing the mucosa with interrupted sutures. No other
dressing is needed if the approach is performed correctly and there is adequate
muscle for suspension and closure.
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29.2.4 Postoperative Care
Overnight observation after GA or genioplasty surgery is highly recommended
because of the risk of sublingual hematoma formation or tongue swelling that may
lead to upper airway obstruction. When the patient undergoes multilevel surgery,
including septoplasty, pharyngoplasty, and GGA, a higher level of overnight care
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Fig. 29.5 Genioplasty advancement can address dentofacial deformity, decrease possible mentalis strain, and still provide tension for the suprahyoid muscles. Diverse types of plates may be
used according to the case
S. Y.-C. Liu and K. Schwartz
may be needed. The decision depends on the type and length of surgery, perioperative complications, comorbidity of the patient, OSA severity, and the possibility of
CPAP use. Postoperative pain control is managed with oral analgesia. Patients can
begin with a mechanical soft diet for comfort but should not have restrictions after
mucosal wound healing, which is most accurately assessed at 2 weeks
postoperatively.
29.2.5 Complications
GA is associated with wound infections, persistent paresthesia of the anterior lower
lip, and dental injury, with incidence rates of 2%, 6%, and 1%, respectively [37].
Mandibular fractures in the symphysis region can occur, particularly in the techniques that violate the inferior border of the mandible. Alternatively, if the osteotomy is superior to the alveolar bone, alveolar fractures can occur and are more
challenging to address than inferior border fractures. The lower border fractures
lend themselves to further open reduction and xation. The superior border fracture
can only be addressed with maxillomandibular xation (arch bars) for several
weeks. Intraoperatively avulsion of the genioglossus muscle from its attachment at
the posterior mandibular border is the worst complication in GA surgery and is a
serious airway risk.
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29.3 Maxillomandibular Advancement
Maxillomandibular advancement (MMA) remains one of the most effective surgical
interventions for patients with OSA.Riley and Powell pioneered the procedure at
Stanford Hospital in the late 1980s The surgery addresses both skeletal support and
soft tissue suspension of the upper airway, which treats OSA and airway collapsibility [38]. MMA enlarges the upper airway space at multiple anatomic locations,
including the nasopharynx, oropharynx, and hypopharynx [39]. MMA involves Le
Fort I maxillary and bilateral sagittal ramus split mandibular osteotomies with
advancement of the maxilla and mandible, and frequently accompanied by counterclockwise rotation [40]. The counterclockwise rotation with an adequately selected
rotation center allows for a more signicant lower jaw advancement than the upper
while maintaining proper occlusion and facial balance. The anatomic limit of counterclockwise rotation depends on (1) maxillary incisal show and (2) the length of
mandible that is available for adequate xation after rotation and advancement.
Ultimately, the terminology of MMA, suggesting advancement only, is not entirely
captive of the complexity of maxillary and mandibular movements (Fig.29.6).
A meta-analysis by Holty and Guilleminault examined 22 studies involving 627
patients who underwent MMA and reported a mean AHI decrease from 63.9 to 9.5
events per hour [41]. The surgical success rate was 86%, and the cure rate (AHI <5)
was 43.2%. Predictors of increased surgical success include younger age, lower preoperative AHI and BMI, and a greater degree of maxillary advancement. An updated
meta-analysis with 45 studies and 528 patients reported a surgical success and cure
rate of 85.5% and 38%, respectively [42]. In 40 patients who underwent MMA with
an average follow-up of 4.2years (range 1–12years), 36 (90%) maintained a signicant reduction in the respiratory disturbance index from 71.2 to 7.6 events per hour
with improvement in daytime sleepiness [43]. Following MMA, most patients report
improvements in health-related quality of life, depression, excessive daytime sleepiness, memory impairment, and hypertension [44]. It has also been shown to improve
sleep architecture by increasing the percentage of rapid eye movement (REM) sleep
and decreasing wakefulness after sleep onset (WASO) [45, 46].
Fig. 29.6 Counterclockwise rotation depending on (1) maxillary incisal show and (2) the length
of mandible that is available for adequate xation after rotation and advancement. Improvement of
airway is seen at the velum, oropharynx, and tongue base
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S. Y.-C. Liu and K. Schwartz
29.3.1 Indications
MMA is recommended for: (1) patients with moderate to severe OSAS with or
without a history of phase 1 surgery (tonsillectomy, uvulopalatopharyngoplasty
with genioglossus advancement), (2) OSA patients of any severity with concurrent
dentofacial deformity, and (3) concentric and lateral pharyngeal wall collapse seen
in DISE [4–6, 47]. (Fig.29.1).
29.3.2 Preoperative Planning
OSA patients planned to have MMA surgery may present with a normal class I
occlusion or varying degrees of malocclusion. In patients with malocclusions or
dental compensated class II or class III occlusion, orthodontic treatment in conjunction with MMA can facilitate more optimal skeletal advancement of the maxillofacial complex.
Preoperative surgical planning of MMA has changed dramatically with the introduction of virtual-surgical planning (VSP). With a computer tomography (CT) or
cone beam computer tomography (CBCT) scan of the face, and dental or digital
models in the desired occlusion, surgeons can use VSP to plan skeletal movements
with versatility and precision. VSP also generates anatomical landmarks and information to be used intraoperatively: (1) distance from the mandibular cortex to the
inferior alveolar nerve, (2) height of the lingula relative to the occlusal plane, (3)
impact of occlusal plane changes associated with counterclockwise rotation, and (4)
presence of anatomic anomalies.
Custom plating can increase precision and decrease operative time in MMA surgery. It is important to note, however, that, unlike classic orthognathic surgery, the
exact position of the maxillomandibular complex is subject to alterations or adjustments intraoperatively, in which case the preplanned plates may not work. The
senior author typically plans cases with two movements, where one usually has
more rotation and less advancement, and the other has less rotation and more
advancement. Since the surgeon intraoperatively controls the pitch, having these
two plans and their associated intermediate splints allows for a wide range of movements to optimize breathing and beauty.
Classic orthognathic surgery is planned with the patient in the so-called “natural
head position.” This is with the patient standing relaxed, facing forward, while the
clinician assesses the patient from the side, prole view. As many patients with
long-term OSA have an exaggerated forward head tilt, planning from this position
will mask the degree of maxillomandibular deciency. Therefore, it is important to
gently guide the patient’s head position such that the neck is in a straight, neutral
position, while the face maintains the Frankfort horizontal. It is important to remember that an OSA patient’s “natural head position” is frequently natural but not
healthy. With maxillofacial surgical treatment, patients can frequently restore less
strained neck and body posture with retraining.
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29.3.3 Surgical Technique
Nasal RAE tubes are frequently used in orthognathic surgery. However, OSA
patients often have longer airways, where RAE tubes tend to fall short. The cuff
may come close to the vocal cord, resulting in trauma or inadequate seal, contributing to interoperative air leak or hypoventilation. To address this, the larger lumen
RAE tubes tend to be used, severely distorting the nose. Strategy, including the use
of a micro-laryngeal tube (MLT) positioned adequately with a 120-degree reverse
metal connector, is described in our broader, overall strategy to optimize nasal function during MMA [48].
The sequencing of MMA surgery is based on the surgeon’s experience and preference. Mandible-rst approach has been recommended to remove potential condylar position errors in the interocclusal registration before surgery [49]. However,
committing to the mandible rst means that there is no room to adjust the maxilla if
it is deemed during surgery that more advancement or rotation (both clockwise or
counterclockwise), is desirable. As systematic reviews and meta-analyses have
shown the maxilla to be the critical driver to surgical success, the maxilla rst may
be preferable for the airway. Fortunately, in the era of VSP, where custom maxillary
plates can be designed, this may mitigate the classic issue of condylar registration
preoperatively.
Patients who are not in orthodontic braces are initially equipped with arch bars
or intermaxillary xation (IMF) screws. To access the maxilla, a mucosal incision is
made approximately 1cm superior to the mucogingival junction from the premolar
area to the premolar area perpendicular to the maxilla. Subperiosteal dissection is
then performed with a periosteal elevator within the following boundaries: (1) medially to the piriform rims, (2) superiorly to the area of the infraorbital nerve foramen,
(3) laterally to the inferior zygomatic and maxillary buttress, and (4) nasal oor
posteriorly to the palatine bone. A curved freer elevator may assist with the dissection of the nasal mucosa, and it is easiest to begin the exposure from the lateral
aspect of the perform aperture and proceed in an inferior-medical direction. A toeout retractor is placed in the pterygomaxillary junction to expose the maxillary buttress. A periosteal elevator or malleable retractor is inserted medially to the piriform
rim to protect the nasal mucosa.
The osteotomy is then initiated at the lateral maxillary buttress and extended
through the piriform rim below the inferior turbinate utilizing a reciprocating saw.
The osteotomy is then mirrored on the contralateral side, and the lateral maxillary
buttress can then be “back cut” by reinserting the reciprocating saw into the lateral
portion of the osteotomy and passing it in a medial to lateral direction.
Disjunction of the maxilla from the septum, medial nasal wall, and pterygomaxillary junction is completed with straight and curved osteotomes. Down-fracture of
the maxilla is performed with gentle digital pressure at the anterior nasal spine
region. Completing the down-fracture should be followed by careful inspection for
any active bleeding, that needs to be controlled. Efforts should be made to preserve
the descending palatine arteries by carefully removing the maxillary pyramidal
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process that may lacerate the vessel during mobilization, advancement, and impaction of the maxilla. In addition, the removed bone pieces from the maxilla can be
used for later bone grafting of the osteotomy sites.
A thorough mobilization of the maxilla important to allow a tension-free repositioning of the maxilla into the planned position. A 24-gauge wire with a Kocher
clamp through the anterior nasal spine is used to perform simultaneous traction of
the anterior maxilla toward the right and left while gently pushing the posterior
maxilla anteriorly with a distractor. In large counterclockwise rotations, further
mobilization is performed by pushing the posterior maxilla downward while holding the anterior maxilla upward. The use of Rowe’s disimpaction forceps transmits
excessive force and is strongly discouraged by the rst author. The key to the mobilization of the maxilla is not in pulling it forward but in rocking it sideways. The
excessive force with the Rowe forceps in older patients is especially problematic
with the risk of unintended fractures.
A planned impaction will require bone reduction and reduction of the nasal septum to allow for appropriate repositioning and to prevent nasal septal deviation. The
piriform aperture and nasal oor widening are performed with a pineapple burr.
Septoplasty can also be performed with an exposure of the septum inferiorly. These
modications improve both form and function of the nasal structures after MMA
[48]. In reality, to achieve an esthetic nose after MMA, the entire process includes
pre-, peri-, and postoperative considerations. Our results from patient-reported outcome measures are favorable with the advent of these considerations [50].
With the maxilla and mandible secure in the intermediate splint, measurements
are made to ensure movements planned for yaw, cant, and pitch are accurate. The
maxilla can be xated in various of ways, using the vertical pillars of strength (piriform and buttress). The suspension wiring technique is highly desirable especially
with older patients and more signicant movements. They are discussed in detail as
part of the contemporary Stanford MMA, though it has been utilized since the procedure’s earliest days [40].
Access to the mandible begins with a vestibular incision starting 10–15mm posterior to the second molar and continues 1cm inferior from the mucogingival junction to the second premolar. This incision should be through the buccinator muscles
and allow a muscular cuff to close after mandibular advancement. The subperiosteal
elevation is made buccally in the rst and second molar, and the inferior border of
the mandible is stripped. The anterior border of the ramus is elevated, and the temporalis muscle attachment is stripped to gain access to the medial ramus. The location of the lingula is either directly visualized or probed with a blunt nerve retractor.
If the subperiosteal elevation at the medical ramus is performed correctly, one
should obtain a “tent effect,” in which a curved retractor reects the entire soft tissue
ap and exposes the medical surface of the ramus and protects the inferior alveolar
nerve posterior to it.
To improve visibility and access to the medial ramus, a round oval bur can be
used to trim a groove toward the lingula. The bony protuberance of the lingual
should be removed for more predictable split that allows for the maximum area of
contact after mandibular advancement. The sagittal ramus split osteotomy is made
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with a reciprocating saw well seated in the groove created. Various ultrasonic cutting instruments have also become popular. To maximize bony overlap in signicant
advancement, the anterior vertical osteotomy is made just to the midline of the
inferior cortex. A deeper osteotomy cut in a lingual direction beyond the midline of
the inferior cortex results in a thin posterior lingual bone plate that can be insufcient for bicortical screw xation in large advancements [51].
Splitting and separation of the tooth-bearing segment from the condylar segment
begins with completion of the medical ramus osteotomy with a straight osteotome.
Straight osteotomes are sequentially wedged together to widen the gap at the anterior part of the osteotomy until a complete separation is achieved. The separation
and location of the inferior alveolar nerve is checked before the tooth-bearing segment is mobilized thoroughly. The tooth-bearing segment is then advanced and
placed into the nal splint. When movements are signicant, the suspension wires
described earlier are highly desirable to begin the process of wire maxillomandibular xation prior to rigid plate xation. The suspension wires, which are anchored to
parts of the facial bone not involved in the osteotomies, confer stability to maxillomandibular xation.
Fixation of the mandible begins with a trocar-assisted access for perpendicular
placement of bicortical screws through the condylar and dentate segments. The
assistant surgeon holds the condylar segment ensuring proper condylar seating. It is
desirable to have the condylar segment placed slightly lower than the dentate segment at the inferior border. In essence, one is creating a longer ramus by using part
of the body of the mandible. The biomechanics, in a signicant advancement with
such a placement, place less stress on the condyle and reduces the likelihood of a
condylar sag. Typically, two bicortical screws are placed, followed by a 1.5mm
thick plate spanning the advancement gap. Therefore, the plate sits passively on the
bone, and nonlocking screws are used.
After xation, the wire MMF is released, and the mandible should be rotated in
and out of the nal occlusion to conrm a (1) stable rotation, (2) reproducible occlusion, and (3) bilateral canine excursion. The osteotomy gaps in the mandible and
maxilla can be grafted to facilitate bone healing postoperatively. Prior to the closure
of the vestibular incision, the septum is checked for passive seating along the maxillary crest. An alar cinch suture with 3-0 Vicryl is used to restore alar base width. The
mucoperiosteal ap is closed with 3-0 chromic in a continuous fashion, and V-Y
anterior lip lengthening may be considered. The sagittal split incisions are closed
with 3-0 Vicryl in interrupted sutures. Guiding elastics are placed in a class II
direction.
Final splints, commonly used postoperatively in classic orthognathic surgery, are
an added burden for OSA patients. OSA patients are frequently anxious about
breathing, and the placement of a nal splint and expected postoperative nasal congestion make for a difcult initial postoperative period. Furthermore, without the
nal splint, dental remodeling can often work in the patient’s favor as part of the
accelerated orthodontics movement. Unless there are special considerations in
surgery- rst orthodontic set-up, where the occlusion is designed in a particular way,
nal splints are not recommended nor needed postoperatively.
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29.3.4 Postoperative Care
OSA patients are predisposed to dynamic airway collapse, and prevention of airway
obstruction after MMA surgery is the top priority. The level of care for MMA
patients postoperatively is determined by patient, surgeon, and hospital systemrelated factors. Historically, patients at Stanford were extubated in the OR but kept
overnight in the ICU for observation. Currently, with advances in anesthesia, surgical time, and postoperative care, patients are sent to a regular ward familiar with
MMA patients postoperatively. The typical stay is two nights, which patients familiarize with a liquid diet and nasal irrigation and are comfortable with pain control.
A mean arterial pressure below 90mm Hg is helpful to minimize the risk of
epistaxis associated with the LeFort I osteotomy. To prevent postoperative edema,
patients receive intravenous corticosteroids. Postoperative pain control is essential
but excessive sedation of OSA patients should be avoided. Intravenous antibiotic is
given in the beginning of surgery and an empiric prophylaxis is continued for a total
of 5–7days.
Nasal saline rinses are initiated on the rst postoperative day to improve nasal
patency. Patient requirements for discharge include reasonable pain control in oral
medication, adequate oral intake, and a patent airway. The arch bars or suspension
wires are removed 6–8 weeks after surgery, together with a postoperative
DISE.Sleep studies are conducted 10–12months after surgery to allow adequate
time for airway muscle remodeling and neuroventilatory reexes stabilization.
Paresthesia of the V2 and V3 nerves are known side effects from orthognathic or
MMA surgery. MMA surgery, with its larger mandibular skeletal movement, the
inferior alveolar (IA) branch of the V3 nerve is the most affected (Fig.29.7). Patients
Fig. 29.7 In MMA
surgery, the inferior
alveolar (IA) branch of the
V3 nerve is the most
affected
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are counseled on the possibility of long-term or permanent numbness of the chin
and lower lip region. Injury to the nerve occurs during the mandibular split, which
is frequently performed in older patients without much marrow space in the mandible. When the condylar and dentate segments are xated, the compression of the
IA can also prolong paresthesia. Finally, the stretch of the nerve also contributes.
From the Stanford team, we advise patients concerned about permanent numbness
of the chin and lower lip, even in a small distribution, to reconsider MMA surgery
very carefully. To minimize the impact of IA paresthesia, patients are recommended
perioperative high dose of omega-3 supplementation. An aggressive neurobiofeedback exercise postoperatively has also been helpful for patients. Surgical techniques
described above with regards to the wedging versus mandibular split technique pioneered by Riley and Powell are also essential for optimizing the osteotomy and
protecting the IA nerve.
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29.3.5 Complications
MMA confers higher rates of complications than orthognathic surgery in younger
patients with dentofacial deformity [52]. There are signicantly higher infection
rates, hardware failure, and the need for reoperation. Compared to patients undergoing routine orthognathic surgery, OSA patients undergoing MMA have signicantly
more dysesthesia, infection, velopharyngeal insufciency, need for hardware
removal, and need for reoperation.
Avascular necrosis of the palate is a rare complication. If there is an indication
that the blood supply to the maxilla is inadequate the surgeon should reposition the
maxilla to its original position and suspend the procedure. Besides greater efcacy
with single piece maxillary advancements, risk of avascular necrosis further discourages multipiece maxillary osteotomies for OSA patients.
Postoperative functional or cosmetic nasal problems that require surgical intervention affect up to 18% of patients undergoing MMA.However, techniques from
Stanford have greatly improved this outcome, both objectively and patient-reported
[48, 50].
Overall, MMA is a safe procedure regarding mortality rate, but OSA patients
should be counseled preoperatively regarding the relative increased risk of complications known to similar maxillofacial procedures.
29.4 Maxillary Expansion Surgery
Maxillary morphology is an essential anatomic element for the obstructive sleep
apnea (OSA) pathophysiology [53]. OSA patients with transverse maxillary hypoplasia and high-arched and narrow hard palate struggle with increased nasal airow
resistance and an inferior–posterior tongue resting position that worsens hypopharyngeal airway collapse [54] (Fig.29.8). Healthy people breathe through the nose
during sleep, generally, with a total sleep time of less than 4% reported as oral
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