Maxillomandibular Advancement for Obstructive Sleep Apnea

Introduction

The fundamental principle of maxillomandibular advancement (MMA) is to move the muscular attachments of the hard palate, tongue, and suprahyoid soft tissue in an anterior direction by advancement of the tooth-bearing segments of the maxilla and mandible. This maneuver enlarges the bony vault, effectively improving retropalatal, lateral wall, and retroglossal airway collapse.

MMA has been used effectively for adults with obstructive sleep apnea (OSA) since the 1980s. During that period, Drs. Robert Riley and Nelson Powell modified orthognathic (i.e., for treatment of occlusion and cosmesis) techniques for telegnathic (i.e., for treatment of OSA) treatment. Over the past 30 years, the data consistently demonstrate greater than 90% success rates, with success defined as postoperative apnea-hypopnea index (AHI) less than 20 and a 50% reduction in baseline AHI.

Although this surgery represents a highly effective modality, its relative invasiveness and prolonged recovery often deter surgeons and patients alike from using MMA as a first-line surgical treatment. However, in otherwise healthy OSA patients with significant retrognathia or maxillary hypoplasia, this surgery can be first line because it provides orthognathic in addition to telegnathic benefits.

Key Operative Learning Points

Proper fabrication of intermediate and final occlusal splints is critical to achieving precise results.
The Le Fort I maxillary osteostomy must be carried out above canine roots and parallel to occlusal plane.
The bilateral sagittal split mandibular osteotomy should be placed at the posterior aspect of the second molar to allow for enough room for plate fixation, if needed.

Preoperative Period

History

A comprehensive sleep medicine history is the critical first step before considering surgical therapy for any OSA patient.
Approximately one-third of OSA patients have been reported to have another primary sleep disorder or sleep-modulating medical comorbidities, such as psychophysiologic insomnia, chronic pain, shift work sleep disorder, restless legs syndrome, or narcolepsy. Medications that negatively affect control of breathing (e.g., opiates or benzodiazepines) or alter sleep architecture or continuity directly (e.g., antidepressants) must also be taken in account in evaluating a patient’s candidacy.
In addition to a sleep medicine history, documentation of a general medical history is paramount.
Patients must be in good health overall because this surgery can result in significant blood loss and requires approximately 4 to 6 hours of general anesthesia.
Patients must also be mentally well with a strong support network. The first 1 to 2 months of the recovery process are particularly challenging given difficulties with trismus and persistent perioral numbness. The perioral numbness can cause significant social impairment with unacceptable drooling and difficulty kissing.
If patients have a history of anxiety or depression, we recommend that the patient see a mental health professional prior to surgery. Empiric medical treatment prior to surgery should be strongly considered.

Physical Examination

1.
Nose
- a.
  Evaluate width of nasal base
  - 1)
    Patients should be informed of some degree of widening of nasal base with maxillary advancement.
- b.
  Acquired nasal deformity, septal deviation, turbinate hypertrophy, rhinitis, nasal polyps, and other nasal valve pathology may increase upper airway resistance and directly contribute to sleep-disordered breathing.
  - 1)
    If nasal obstruction requires treatment, it should be performed AFTER MMA because the healing from the maxillary advancement may disrupt septal alignment.
2.
Facial skeleton evaluation
- a.
  Maxilla
  - 1)
    Evaluate transverse, vertical, and anteroposterior dimensions.
    - a)
      Multipiece Le Fort osteotomy or a surgically assisted rapid palatal expansion (as a separate initial procedure) may be required to improve the transverse dimension.
    - b)
      Maxillary impaction should be considered in cases of vertical maxillary excess.
- b.
  Mandible
  - 1)
    Evaluate width of mandibular vault and retrognathia.
    - a)
      Retrognathia should be differentiated from microgenia based on occlusal relationship and reference of the lower incisors and chin to the cranial base.
- c.
  Dentition
  - 1)
    Use of Angle occlusion at the first mandibular and maxillary molars and canines represents occlusal relationship and can assist in determining any skeletal malocclusion.
  - 2)
    Evaluate for open bite deformity or buccal/lingual crossbite.
  - 3)
    If correction of malocclusion is indicated, consider preoperative orthodontics.
  - 4)
    Evaluate the health of teeth based on enamel, periodontal status, and presence of extensive restorations. Crown and bridge work may alter plans for maxillomandibular fixation.
3.
Soft tissue evaluation
- a.
  Transoral examination
  - 1)
    Evaluate the position of the tongue and soft palate.
- b.
  Fiberoptic examination
  - 1)
    Retropalatal space
    - a)
      Space from the posterior nasal spine to posterior pharyngeal wall will be increased with maxillary advancement.
    - b)
      If previous uvulopalatopharyngoplasty (UPPP), assess for soft palate scarring or nasopharyngeal stenosis.
  - 2)
    Lateral wall collapse (Müller maneuver or under sedated endoscopy) as MMA provides tension to lateral walls to prevent collapse
  - 3)
    Retrolingual and hypopharyngeal space. Both tongue base and epiglottic obstruction can be treated with MMA.
  - 4)
    Lymphoid hyperplasia (e.g., palatine or lingual tonsil hypertrophy). Excessive intraluminal lymphoid tissue may need to be removed simultaneously or in a staged fashion with MMA.

Imaging

1.
Photodocumentation
2.
Plain films—primarily orthopantomogram and lateral cephalometric radiograph
3.
Computed tomography (CT) or cone beam computed tomography (CBCT)

Computer-Assisted Planning and Splint Fabrication

1.
Imaging allows improved understanding of deformities in multiple dimensions.
2.
Virtual planning is developing into the standard for treatment of complex dental and facial reconstructions.
3.
Virtual planning provides insight to anticipated anatomic relationships at osteotomies prior to surgery, allowing for efficient and detailed preoperative plans.
4.
Laboratory time can be eliminated with accurate splints fabricated for intraoperative MMF. Splints can be fabricated to individual specifications (i.e., sandwich splints for multipiece double jaw surgery or addition of a palatal strap for maxillary widening).
5.
Accurate and efficient interdental osteotomy guides can be fabricated from the patient data to prevent root damage.

Indications

1.
Moderate to severe OSA with failure of medical device therapy
2.
Mild to severe OSA with craniofacial anomaly

Contraindications

1.
Central sleep apnea
2.
Bisphosphonate medications use
3.
Uncontrolled medical comorbidities
4.
Recent history of maxillary or mandibular surgery with potential compromise of skeletal blood supply (e.g., transpalatal advancement pharyngoplasty)
5.
Severe temporomandibular joint (TMJ) dysfunction

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