1
Indications
From our first case report describing isolated mandibular advancement for the treatment of obstructive sleep apnea (OSA) in 1984, maxillofacial surgical interventions have played significant roles in sleep surgery. Single jaw advancement evolved to maxillary and mandibular advancement (MMA) surgery in the mid-1980s with consistently improved postoperative outcomes in OSA patients.
As an isolated or multilevel procedure, we also described the original genioglossus advancement (GGA) surgery for stabilization of the tongue base. As part of the original phased Stanford protocol, when the preoperative evaluation implicated the base of the tongue (Fujita type II–III) as a source of airway obstruction, GGA was performed as a conservative osteotomy to place the genioglossus, a primary protrusor tongue muscle, under direct tension. The increased tension on the tongue is proposed to resist the collapse of the tongue into the airway that can occur with sleep-induced hypotonia. Patients with residual OSA after phase 1 were then considered for phase 2 surgery: the MMA.
In the original protocol, presurgical evaluation consisted of a comprehensive medical history, head and neck examination, fiber-optic nasopharyngolaryngoscopy, radiographic cephalometric analysis, and polysomnography. Today, the lateral cephalometric analysis is largely replaced by a noncontrast fine-cut maxillofacial computed tomography (CT) scan that can be reconstructed to afford three-dimensional views of the maxillofacial skeleton and posterior airway space. It can also be used for virtual surgical planning (VSP).
The advent of drug-induced sedation endoscopy (DISE) has further augmented our ability to identify patients who would benefit from bypassing phase 1 and going directly to MMA. Liu et al. have identified two key predictive preoperative airway collapse patterns under DISE for surgical success with MMA first: (1) severe lateral pharyngeal wall collapse with (2) circumferential collapse of the velum ( and ).
We have also diversified our original GGA with a patient-specific GGA that is designed preoperatively with VSP. We typically include the inferior border of the mandible and the genial tubercle to capture both the genioglossus and suprahyoid muscles with improved accuracy.
In this chapter, we focus on technical nuances and contemporary refinements to our MMA and GGA techniques that have been cultivated since the previous edition.
2
Contraindications
Age is a relative contraindication to skeletal surgery, although there are no reliable studies for determination of bone-healing capacity. The oldest patient who effectively underwent MMA to date is 67 years old with no adverse outcome. Patients with rheumatoid arthritis, temporomandibular joint derangement, history of intravenous bisphosphonate use, and connective tissue disorders require further evaluation to determine candidacy for maxillofacial surgery. Other contraindications include compromised lung function, unstable cardiac pathology, drug or alcohol addiction, and psychological instability. Dental limitations such as partial or complete edentulism, severe periodontal disease, and malocclusion are not absolute contraindications, but present challenges that warrant expert assessment.
3
Alternative Treatment Options
Positive airway pressure (PAP) therapy, weight loss, positional therapy, and dental devices are nonsurgical treatments, with PAP being the mainstay. Palatopharyngoplasty, tongue base surgery, tongue suspension surgery, and upper airway stimulation can be effective surgical options, especially with multilevel treatment. Bariatric surgery and tracheostomy are options for specific patient phenotypes.
4
Anesthesia
4.1
Maxillomandibular Advancement
Although nasal RAE tubes are frequently used in orthognathic surgery, OSA patients tend to have longer airways, and RAE tubes tend to fall short. The cuff may be too close to the vocal cords and cause trauma or inadequate seal, contributing to intraoperative air leak or hypoventilation. We prefer using a microlaryngoscopy tube to the proper depth. The tube can be cut, leaving about 1 cm from the nasal sill, and a 120-degree metal attachment is used to direct the tubing across the patient’s forehead with no pressure to the alae. The patient is in a supine position and turned 180 degrees away from the anesthesiologist. The accordion extension tubing is helpful. If MMA surgery is performed with concurrent orthognathic correction of dentofacial deformity, corneal shields to protect the globes are used to allow vertical distance measurements from the medial canthus to skeletal landmarks.
Balanced total intravenous anesthesia with agents such as propofol and remifentanil to minimize use of volatile agents is recommended. Advantages include rapid emergence and decreased postoperative nausea and vomiting, which are priorities for MMA patients extubated with restricted jaw opening. Preemptive analgesia is achieved with V 2 and V 3 nerve blocks using 1% lidocaine with 1 : 100,000 epinephrine.
With controlled hypotension (mean arterial pressure of 60 mm Hg) during maxillary down-fracture, autologous blood donation before surgery is unnecessary. Usual blood loss for MMA ranges from 250 to 350 mL.
Postoperatively, patients are extubated in the operating room (OR) with the anesthesiologist and surgeon working closely together. The surgeon assists in nasal and oral suctioning with a 16-French tube that easily negotiates the nasal passages and buccal corridors of the mouth. Patients are never “wired” shut. With our patients, only a few elastics bands are placed in a class 2 direction.
4.2
Genioglossus Advancement
An oral endotracheal tube is adequate for GGA performed in isolation or part of phase 1 surgery. A reinforced tube allows the flexibility to swing the tube toward the oral commissures and can be secured to any molar tooth via a 24-gauge wire to prevent dislodgement.
5
Operative Techniques
5.1
Maxillomandibular Advancement
5.1.1
Preoperative Preparation
Preoperative planning for MMA has changed dramatically with VSP. Labor-intensive steps associated with MMA planning previously involved obtaining dental impressions, mounting dental models, performing model surgery, and fabricating occlusal splints. With CT scanning of the patient in natural head position and dental models set in desired occlusion (digital models are also available with intraoral scanners), surgeons are able to use computerized software to plan the operation with unprecedented versatility and accuracy. VSP locates landmarks of utility intraoperatively: (1) distance of the mandibular cortex to inferior alveolar nerve, (2) height of the lingula relative to the occlusal plane ( Fig. 57.1 ), (3) impact of occlusal plane change associated with counterclockwise rotation ( Fig. 57.2 ), and (4) presence of anatomic aberration. The role of cephalometric analysis has limited utility for patients who have concomitant dentofacial deformity. Otherwise, the counterclockwise rotation of the Stanford MMA is aimed at skeletal stabilization of the upper airway with (1) minimal change of the midface, (2) preservation of presurgical occlusion, and (3) tension of the pharyngeal dilator muscles.
5.1.2
Operative Techniques
Surgery begins with the application of arch bars if patients are not in orthodontic braces. Access to the Le Fort I osteotomy begins with an incision approximately 1 cm superior to the mucogingival junction in the maxillary vestibule. The location of Stenson duct openings should be noted before incision. The lateral extent of the incision should allow easy exposure of the maxillary buttress, but not be too wide as to expose the buccal fat pad. Subperiosteal elevation is made within the following boundaries: (1) superiorly to the infraorbital nerve foramen, (2) laterally to the inferior zygoma and maxillary buttress, and (3) medially to the piriform rim and up to 2 cm superior to the nasal floor.
A curved freer is used to elevate the nasal mucosa, and it is easiest to begin exposure from the lateral aspect of the piriform aperture and proceed in an inferior-medial direction.
A toe-out retractor is placed against the pterygomaxillary junction to expose the maxillary buttress, and a smaller malleable retraction is inserted medially to the piriform rim to protect the nasal mucosa. A reciprocating saw is used to create an osteotomy from the midpoint of the lateral maxillary buttress to the piriform rim below the inferior turbinate. The next osteotomy begins approximately 2 to 3 millimeters above the first osteotomy at the piriform rim and tapers as it is directed toward the buttress. The degree of taper depends on the amount of counterclockwise rotation desired while preserving appropriate incisor position. A wedge of anterior maxillary bone graft is removed and saved for later use ( Fig. 57.3 ).
