Maxillofacial Surgical Treatment

     and SAS
  a.1. Indications
         Oral Appliance
   a.3.1. AHI
   a.3.2. Sleep Quality 
   a.3.4. Snoring
   a.3.5. Blood Pressure
   a.3.6. Upper Airway 
             Resistance Syndrome
   a.3.7. Side Effects
   a.4.1. Anatomical Factors
   a.4.2. Functional Factors
   a.4.3. Sleep Position 
         Periodontal Disease
         Heart Disease
         Metabolic Syndrome

Surgery is generally indicated when applicable conservative therapies are unsuccessful or not tolerated, as well as for patients who have an identifiable underlying surgically correctable abnormality that is causing the SAS [110]. The three major anatomic regions of potential collapse during sleep in SAS patients are the nose, palate, and tongue base. Examination of the oral cavity should include an evaluation of dental health, class of occlusion, and the characteristics of the oral mucous membranes and tongue. The pharynx should be examined by assessing the length of the soft palate, any lateral pharyngeal redundancy, and the size of the tonsils. Cephalometric radiographs assist in the overall evaluation of the soft tissue and bony configuration. However, such cephalometric evaluation is limited because the patient is evaluated while awake and seated, and because it is not a dynamic study obtained during sleep. Surgical procedures that are considered include uvulopalatopharyngoplasty, laser midline glossectomy and lingualplasty, inferior sagittal mandibular osteotomy and genioglossal advancement with hyoid myotomy and suspension, maxillomandibular osteotomy and advancement, and tracheotomy.

An epidermoid or dermatoid cyst in the sublingual area can press the tongue posteriorly and result in apnea and snoring Figure 19a, b). An extremely large mandibular torus can also cause apnea (Figure 19c, d). Symptoms will improve if the mandibular torus or cyst are removed. Tongue reduction surgery can be performed in SAS patients with macroglossia. If a SAS patient is not obese, and there is no obvious problem in the otolaryngeal region, an abnormality may be recognized in the stomatognathic system, and the diagnosis of the oral surgeon is important.

Figure 19. Structural problems in the oral cavity resulting in SAS. Excessive large mandibular torus (d), large uvula (c), epidermoid or dermoid cyst (a,b) in sublingual region can cause SAS.

  b.1. Orthognathic Surgery
Here, the author focuses on the stomatognathic region. The Powell-Riley surgical protocol is a two-phase procedure that directs surgical treatment toward the specific regions of obstruction during sleep [111]. Phase I of the surgical intervention includes nasal reconstruction, uvulopalatopharyngoplasty, and a limited mandibular osteotomy with genioglossus advancement-hyoid myotomy and suspension. Phase II represents skeletal reconstruction and consists of bi-maxillary advancement, commonly referred to as maxillary and mandibular osteotomy. Surgery for SAS is primarily aimed at enlarging the airway while decreasing its collapsibility. Several different protocols for surgical treatment in SAS have been adopted. Prinsell [112] adopted a “site-specific” approach in which patients with “orohypopharyngeal narrowing caused by macroglossia with a retropositioned tongue base” are considered eligible for maxillomandibular advancement surgery. Mandibular advancement surgery such as sagittal splitting osteotomy, which is a representative orthognathic surgical method, can be used to treat SAS of congenital micrognathia like Pierre Robin’s sequence (Figure 20) [113], Treacher Collins syndrome and Hallermann-Streiff syndrome (Figure 21). Maxillomandibular advancement surgery for SAS patients consists of a bilateral sagittal splitting osteotomy of the mandible and a Le Fort I osteotomy of the maxilla. Maxillomandibular advancement surgery is regarded as the most effective and acceptable surgical procedure for SAS with a success rate of 75 % to 100 % [37, 114-116]. However, the results are based on varying criteria such as a postoperative AHI of less than 20 or a greater than 50 % reduction in AHI [37], less than 15 [118], less than 10 [114], less than 15 or a reduction in AHI and AI of greater than 60 % [37]. The current technique of sagittal splitting ramus osteotomy follows descriptions published by Obwegeser in 1964 [118]. Today, sagittal splitting ramus osteotomy is the most commonly used procedure in the treatment of maxillofacial deformities such as prognathism or retrognathism. Le Fort I maxillary osteotomy is a common orthognathic surgical procedure. A transverse separation of the dentoalveolar process of the maxilla to include the palate, floor of the nose, and the maxillary sinuses in order to widen, narrow, lengthen, shorten, or level the upper jaw is done so that it can be placed in harmony with the other facial bones, as well as the skull.

Figure 20. A patient with sleep-disordered breathing due to micrognathia related to Pierre Robin Complex. His mandible was advanced by performing sagittal splitting osteotomy and genioplasty and the respiratory symptom and esthetic problem were improved.

Figure 21. A patient with Hallermann-Streiff syndrome with sleep-disordered breathing. The patient has an extremely small mandible and showed severe SAS with AHI of 70-90.

  b.2. Distraction Osteogenesis
Distraction osteogenesis is a technique in which bone can be lengthened by de novo bone formation as part of the normal healing process that occurs between surgically osteomized bone segments. Distraction osteogenesis is playing a rapidly expanding role in the treatment of airway obstruction and craniofacial deformities resulting from mandibular deficiency. Mandibular distraction osteogenesis is frequently performed in apneic children [119, 120] with congenital anomalies, and also in adults [121]. Compared with orthognathic surgery, distraction osteogenesis has advantages such as less surgical stress and invasion, no need for bone grafting, induction of soft tissue adaptation, and more extensive bone lengthening. However, it requires more time for the lengthening and formation of the bone. We are now able to extend across difficult long distances, which is impossible with mandibular advancement surgery, by applying distraction osteogenesis (Figure 22) [122].

Figure 22. Mandible was advanced in a patient with micrognathia 0.8mm per day and totally 14mm in 18 days after corticotomy of the mandible.