Surgical Maxillomandibular Advancement Technique Kok Weng Lye and Joseph R. Deatherage Some of the most severe forms of obstructive sleep apnea are attributed to anatomic abnormalities in the facial skeleton. With the use of conventional orthognathic surgical techniques, it is possible to expand the posterior airway. In fact, there is strong evidence in the literature to support maxillomandibular advancement as one of the most efficacious surgical procedures for the treatment of obstructive sleep apnea (OSA). There are complications associated with this procedure but these are minor when compared with the risk of inadequately treated OSA. (Semin Orthod 2009;15:99-104.) © 2009 Elsevier Inc. All rights reserved.
ard tissue surgery for obstructive sleep apnea (OSA) treatment includes genioglossus advancement (GGA) and maxillomandibular advancement (MMA). Genioglossus advancement surgery initially was described as a rectangular osteotomy at the chin, which contains the genial tubercles.1 GGA has been a frequently performed procedure, but not as an isolated one, to treat OSA. GGA often is performed together with uvulopharyngopalatoplasty, with an acceptable success rate of ⬎80% for moderate OSA (respiratory distress index [RDI] 21 to 40), 64% for moderately severe OSA (RDI 41– 60), and only 15% for severe OSA (RDI ⬎61).2 Other techniques following the same principle of advancing the genial tubercles along with the genial glossal muscles are the inferior horizontal geniotomy and the mortized geniotomy. Kuo et al3 initiated the use of orthognathic surgery for the treatment of OSA in 1979. The treatment involved the advancement of the maxilla and mandible via traditional orthognathic surgery, which was then called MMA. The rationale for this treatment is the advancement of the
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Department of Oral and Maxillofacial Surgery, National Dental Centre, Singapore; Department of Oral and Maxillofacial Surgery, University of Alabama School of Dentistry, Birmingham, AL. Address correspondence to Kok Weng Lye, Department of Oral and Maxillofacial Surgery, National Dental Centre, 5 Second Hospital Avenue, Singapore, 168938. Phone: 65-6324 8890; E-mail: kokwenglye@yahoo.com © 2009 Elsevier Inc. All rights reserved. 1073-8746/09/1502-0$30.00/0 doi:10.1053/j.sodo.2009.01.004
skeletal attachment of the suprahyoid and velopharyngeal muscles and tendons and an increase in volume of the nasopharynx, oropharynx, and hypopharynx. Together, this advancement leads to the anterior movement of the soft palate, tongue, and anterior pharyngeal tissues. Subsequently, an enlargement of the posterior airway and a decrease in laxity of the pharyngeal tissues ensues and results in a decrease in the obstruction of the posterior airway space. Since 1979, there have been several publications that showed overall success rates of 96%,4 97%,5 98%,6 and 100%.7 There is also strong evidence of the long-term efficacy of the MMA approach, as Li et al8 showed a 90% success rate for a group of 40 patients with a mean follow-up period exceeding 50 months. These results are further supported by a study examining the surgical stability of MMA, which found that the large horizontal advancement of the maxilla and mandible is stable and without significant relapse.9 However, there are 2 philosophies regarding the use of MMA. Some groups believed in a 2-stage protocol where MMA is the stage 2 procedure if stage 1, which consists of uvulopharyngopalatoplasty, GGA, and hyoid suspension, fails.6,10 This latter protocol was developed to reduce the use and complications of the more invasive MMA procedure for patients who would have responded to the first-stage procedures. In the landmark study6 from which this protocol was developed, the authors found that the success rate was 60% for stage 1 surgery and 97% for stage 2 surgery. However, only 25% of the
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stage 1 nonresponders went on to stage 2 surgery. This failure to proceed with the stage 2 surgery was probably a result of the trauma experienced from the first surgery and being discouraged by the failure of improvement after the stage 1 surgery. For these reasons, other groups of clinicians believe in using the most efficacious technique from the start and proceeding directly with MMA.4,5 Waite et al,4 in a key study, evaluated 23 patients who had had MMA surgery together with septoplasty and inferior turbinectomies. They achieved a success rate of 96%. Based on the criteria of a 50% reduction in the RDI and a final RDI of less than 20,4 Hochban et al5 and Prinsell7 also used MMA as the primary procedure for 38 and 50 OSA patients, achieving 97% and 100% success rate, respectively.
Indications and Contraindications for MMA To be a suitable patient for MMA treatment, a few prerequisites are necessary.11 The patients’ apnea-hyponea index or RDI must be greater than 15, with a lowest desaturation �90% and subjective excessive daytime sleepiness. In addition, conservative treatments, such as weight loss, mandibular repositioning devices, and/or continuous positive airway pressure, must have been unsuccessful or intolerable for the patient. The patient must also be medically fit to undergo the surgery. If, in addition, the following 2 clinical conditions also are present, then MMA should be the procedure of choice. First, there should be obstruction at multiple sites or obstruction could not be distinguished, as it was diffuse. Second, the patient should present with a dentofacial skeletal deformity and malocclusion, most often a Class II relationship, and the MMA surgery should be able to provide an opportunity to obtain multiple benefits. Obviously, patients who do not meet the criteria for the MMA procedure or who are unwilling and/or unable to undergo MMA surgery should be excluded.
Surgical Planning and Technique MMA is primarily orthognathic surgery in which the maxilla and mandible are advanced through osteotomies. Thus, MMA surgery requires all the
relevant preoperative records and planning, such as facial examination, radiographs, cephalometric analysis, nasopharyngoscopy and model surgery. Ideally, preoperative orthodontic treatment should be used to ensure a good postoperative occlusion as well as correcting any pre-existing malalignment of the teeth to enhance the cosmetic appearance of the patients. However, many OSA patients are older and are unwilling to undergo the recommended orthodontic phase of the treatment, or they may not wish to delay the treatment of their OSA condition. In addition, some OSA patients may have multiple missing teeth, active advanced periodontal disease, or complex fixed prosthodontic restorations, which may complicate orthodontic treatment. Furthermore, the patients’ problem is often a functional one, and they may be less concerned with the esthetic improvement of any treatment. Those patients who, for whatever reason, elect or are advised not to undergo presurgical orthodontic treatment should clearly understand their possible and potential need for postsurgical orthodontic and/or restorative dental treatment.
Orthodontics The objectives of presurgical orthodontic treatment for MMA patients is different from those of routine orthognathic surgery for patients who have dentofacial deformities. For the MMA patients, the purpose of the presurgical orthodontic treatment is to assist in maximizing the anterior positioning of the maxilla and mandible while attempting to obtain a reasonable occlusion. In Class II patients, it is advisable to retract the lower incisor teeth and procline the upper incisor teeth to maximize the amount of mandibular advancement. This step will provide the greatest amount of airway improvement.
Cephalometric Analysis In general, a lateral cephalogram is a standardized and repeatable radiograph that presents the profile view of the viscerocranium. It is a routine tool for the diagnostic workup of all OSA patients and the technique has been previously described.12 Cephalometric analysis helps to confirm the clinical and nasopharyngoscopy findings. The values of different parameters in the analysis can be compared to normal values
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to characterize the craniofacial relationship and the posterior airway status. Cephalometric analysis reveals the severity of any craniofacial dysmorphy or abnormalities. Studies have referred to the retro-positioning of the jaws, a short mandibular length, a long anterior face height, clockwise rotation of the facial structure, short cranial base, and decreased craniofacial flexure angle as common abnormalities found in OSA patients.4,13-17 The underlying principle is that when the craniofacial structure is retropositioned through either underdevelopment in the horizontal plane or a clockwise rotational growth pattern, the structures that form the anterior and lateral boundaries of the posterior airway, such as the palate, tongue, and pharyngeal tissues are displaced posteriorly. The tissues are also lax and more liable to collapse in the presence of negative pressure. This results in the constriction of the posterior airway, increased airway resistance and obstructions. Moreover, the restriction generates turbulence of the airflow and vibration of the redundant tissues, causing snoring. Interestingly, significant craniofacial abnormalities are found in about 40% of these patients.18 In terms of treatment planning, it is an important tool to help identify the patients who have severe craniofacial deficiency (SNB angle � 75°), as they should be directly offered MMA surgery instead of soft tissue procedures.10 Although there are more advanced imaging techniques to study the posterior airway, cephalometric analysis still offers considerable advantages, including low cost, ease of use and minimal radiation exposure. It is also able to analyze the craniofacial morphology, airway status, head position and hyoid position simultaneously. In addition, its acceptable reproducibility enables easy comparisons longitudinally, before and after procedures and between populations.
Technique The MMA is achieved by use of the standard bilateral sagittal split osteotomy technique for the mandible and the Le Fort I level maxillary osteotomy. The mandible is cut and a sagittal split is carried out bilaterally in the posterior body, angle and lower ramus region. The proximal segments with the condyles are kept in the same position while the distal segment; the body of mandible, alveolus and teeth, are advanced
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according to the prefabricated occlusal splint into a Class III relationship. The occlusal splint is made during the presurgical model surgery. The inferior alveolar nerve is kept intact but sustains some tension during the surgical advancement procedure. The distal segment is then fixated with bicortical screws or titanium miniplates and screws. Performing the mandibular advancement first creates a more stable occlusal platform. The advancement of the mandible pulls the geniohyoid, genioglossus, mylohyoid and the digastric muscles anteriorly. This in turn brings the base of tongue and hyoid bone forwards and upwards. In addition, the advancement of the mandible creates a larger volume for the tongue and floor of mouth. These two effects result in the enlargement of the posterior airway space at the retroglossal and hypopharyngeal region level. The maxilla is then cut and mobilized at the Le Fort I level. The advancement is then achieved with the aid of a final occlusal splint or a stable final occlusion. The maxilla is then fixated with 4 titanium plates and screws. There are prebent OSA advancement plates19 that are designed for this purpose and have been shown to be more resistant to relapse.20 Because there is very often a large gap and minimal bony contact between the upper and lower segments of the maxilla, bone grafting is necessary to ensure good bony healing, better stability, and the minimization of relapse.21 Nasal septal defects and enlarged inferior turbinates can be treated via the Le Fort approach after down-fracturing of the maxilla. The generally accepted magnitude of advancement was 10 mm. The 10-mm quantum is not evidenced based, and the authors of the present paper have achieved good success despite surgical advancement of a lesser degree. This is because the change in airway resistance is inversely proportional to the radius of the airway raised to the power of four. The movement of the maxilla and mandible will be the same only in cases in which there is no change in occlusion. Equal maxillary and mandibular advancement also occurs in patients who do not undergo preoperative orthodontic treatment. Patients who have dysgnathia usually are scheduled for orthodontic treatment and improvement of their malocclusion. In patients with dysgnathia who undergo orthodontic treatment the
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maxilla and mandible will obviously not be advanced equal amounts. An additional procedure to complement the MMA is the GGA. This could be done via the rectangular osteotomy technique popularized by Riley et al22 or an inferior horizontal geniotomy; the standard chin osteotomy used in orthognathic surgery. This technique increases the magnitude of repositioning of the genioglossus, geniohyoid and digastric muscles.23 Simultaneous adjunctive soft-tissue procedures can be considered during the MMA procedure. However, any pharyngeal soft-tissue procedures performed simultaneously with MMA may result in airway compromise secondary to bleeding and swelling. These procedures include surgery to the soft palate, tonsils, and the tongue. These cases may need surgical tracheostomy,4 prolonged endotracheal intubation or continuous positive airway pressure use for the period of postoperative edema. In addition, any tension on the soft-tissue closure from the skeletal advancement may lead to poor healing or even fibrosis and scarring.7 Nonpharyngeal procedures, such as nasal procedures, cervicofacial liposuction, or lipectomy can be done simultaneously with MMA because there is no potential airway compromise in these procedures.7
Complications There are no major complications reported for the MMA procedure. Various authors have mentioned some minor complications. As the advancement of the mandible is often 10 mm or greater, the incidence of permanent hypesthesia of the lower lip is one of the commonest problems. Studies have shown long term hypesthesia to be in the range of 13%6 and 20%.10 If there is no concurrent orthodontic treatment, postoperative occlusal changes, such as malocclusion and open bites, are relatively common. This could result in the need for reoperation, postoperative orthodontic treatment, or postoperative prosthodontic rehabilitation. When there has been previous or concurrent soft palate surgery to stiffen or shorten the palate, velopharyngeal insufficiency can occur.24 Velopharyngeal insufficiency results in a lack of palatal closure and allows air escape during speech and swallowing difficulty. This problem is usually temporary and
can be improved with the assistance of speech therapy. Sometimes, speech difficulties from the change in lip position also may require speech therapy. Esthetic alterations, especially widening of the alar base of the nose and superior movement of the nasal tip and a more acute nasolabial angle, are problems that should be discussed with the patient preoperatively. However, many studies have indicated that the facial changes were generally viewed favorably by the patients.25 This change in facial appearance is more of a concern among the Asians population because of the common presentation of bimaxillary protrusion in this group of patients.26 Another complication that may arise is temporo-mandibular disorder (TMD). The TMD is caused by the alteration in the condylar position and increased joint pressure from the large mandibular advancement. Pre-existing TMD is a risk factor that may drastically increase the likelihood of postoperative TMD. Additional reported concerns that may arise are limited range of motion, sinus dysfunction and decreased bite force. These complications have been observed more frequently in older patients. Bettega et al10 encountered some other minor complications, such as local infection, an oro-nasal perforation that healed spontaneously, and maxillary pseudo-union resulting in instability and that required bone grafting. Prinsell11 reported minimal postoperative difficulties with a mean hospital stay of 1.6 days, no significant impairment from the hypesthesia, and good patient acceptance of their facial changes. Waite et al4 also showed 95% patient satisfaction despite the minor complaints.1
Advances in MMA In the presence of modern technology, researchers and clinicians have started using computed tomography (CT) and magnetic resonance (MR) scans to evaluate the posterior airway 3-dimensionally. This is superior to the widely used 2 dimensional cephalograms. However, cephalometric analysis of the airway has been well established and permits measurements at key anatomical locations. Although CT and MR provide extremely accurate distance and area measurements of the airway in all dimensions, there
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are no recognized normal ranges. Furthermore, there is no standardization in the thickness, direction and precise location of the sections as yet.27 In a recent study, 20 patients who underwent MMA had CT scans preoperatively and following surgery to analyze the morphologic changes of the airway.28 The results demonstrated significant increase in both the anteroposterior and lateral airway dimensions after MMA surgery. Another area of interest is the emergence of the “quality-of-life” dimension. This represents the functional effect of an illness and its consequent therapy upon a patient, as perceived by the patient.29 It has been a neglected dimension as clinicians have been treating patients based on results of objective investigation. Nowadays, quality of life is increasingly valued as an important aspect of patient care. There have been very few studies that examined the changes in the quality of life after surgical procedures for OSA.30,31 Lye32 recently reported on MMA having equally high success in achieving significant improvement in the area of quality of life. In conclusion, there is strong evidence to support MMA as one of the most efficacious surgical procedure for the treatment of OSA. It is a safe procedure and the more commonly noted complications are relatively minor as compared to the risk of inadequately treated OSA. There have been some modifications to the technique and inclusion of some adjunctive procedures over the years. There is also essential research being done to provide the latest information on this treatment which will help in our understanding and improve our management of the OSA patient.
References 1. Troell RJ, Riley RW, Powell NB, et al: Surgical management of the hypopharyngeal airway in sleep disordered breathing. Otolaryngol Clin North Am 31:979-1012, 1998 2. Hendler BH, Costello BJ, Silverstein K, et al: A protocol for uvulopalatopharyngoplasty, mortised genioplasty, and maxillomandibular advancement in patients with obstructive sleep apnea: an analysis of 40 cases. J Oral Maxillofac Surg 59:892-897, 2001 3. Kuo PC, West RA, Bloomquist DS, et al: The effect of mandibular osteotomy in three patients with hypersomnia sleep apnea. Oral Surg Oral Med Oral Pathol 48:385392, 1979
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4. Waite PD, Wooten V, Lachner J, et al: Maxillomandibular advancement surgery in 23 patients with obstructive sleep apnea syndrome. J Oral Maxillofac Surg 47:12561261, 1989 5. Hochban W, Conradt R, Brandenburg U, et al: Surgical maxillofacial treatment of obstructive sleep apnea. Plast Reconstr Surg 99:619-626, 1997 6. Riley RW, Powell NB, Guilleminault C, et al: Obstructive sleep apnea: A review of 306 consecutive treated patients. Otolaryngol Head Neck Surg 108:117-125, 1993 7. Prinsell JR: Maxillomandibular advancement surgery in a site-specific treatment approach for obstructive sleep apnea in 50 consecutive patients. Chest 116:1519-1529, 1999 8. Li KK, Powell NB, Riley RW, et al: Long-term results of maxillomandibular advancement surgery. Sleep Breath 4:137-140, 2000 9. Nimkarn Y, Miles PG, Waite PD: Maxillomandibular advancement surgery in obstructive sleep apnea syndrome patients: Long-term surgical stability. J Oral Maxillofac Surg 53:1414-1418, 1995 10. Bettega G, Pepin JL, Veale D, et al: Obstructive sleep apnea syndrome. Fifty-one consecutive patients treated by maxillofacial surgery. Am J Respir Crit Care Med 162:641-649, 2000 11. Prinsell JR: Maxillomandibular advancement surgery for obstructive sleep apnea syndrome. J Am Dent Assoc 133:1489-1497, 2002 12. Riley R, Guilleminault C, Herran J, et al: Cephalometric analyses and flow-volume loops in obstructive sleep apnea patients. Sleep 6:303-311, 1983 13. Hierl T, Humpfner-Hierl H, Frerich B, et al: Obstructive sleep apnoea syndrome: Results and conclusion of a principal component analysis. J Craniomaxillofac Surg 25:181-185, 1997 14. Hochban W, Brandenburg U: Morphology of the viscerocranium in obstructive sleep apnoea syndrome— Cephalometric evaluation of 400 patients. J Craniomaxillofac Surg 22:205-213, 1994 15. Jamieson AC, Guilleminault C, Partinen M, et al: Obstructive sleep apneic patients have craniofacial abnormalities. Sleep 9:469-477, 1986 16. Liano Y, Huang C, Chuang M: The utility of cephalometry with the Muller maneuver in evaluating the upper airway and its surrounding structures in Chinese patients with sleep-disordered breathing. Laryngoscope 113:614619, 2003 17. Steinberg B, Fraser B: The cranial base in obstructive sleep apnea. J Oral Maxillofac Surg 53:1150-1154, 1995 18. Hochban W, Kunkel M, Brandenburg U: Functional anatomy of the upper airway: Cephalometric and reflective acoustic studies. Pneumologie 47:766-772, 1993 19. Lye KW, Waite PD, Wang D, et al: Predictability of prebent advancement plates for use in maxillomandibular advancement surgery. J Oral Maxillofac Surg 66:16251629, 2008
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20. Araujo MM, Waite PD, Lemons JE: Strength analysis of Le Fort I osteotomy fixation: Titanium versus resorbable plates. J Oral Maxillofac Surg 59:1034-1039, 2001 21. Waite PD, Tejera TJ, Anucul B: The stability of maxillary advancement using Le Fort I osteotomy with and without genial bone grafting. Int J Oral Maxillofac Surg 25:264-267, 1996 22. Riley RW, Powell NB, Guilleminault C: Obstructive sleep apnea syndrome: a surgical protocol for dynamic upper airway reconstruction. J Oral Maxillofac Surg 51:742-747, 1993 23. Waite PD, Shettar SM: Maxillomandibular advancement surgery: A cure for obstructive sleep apnea syndrome, In Waite PD (ed). Oral and Maxillofacial Treatment of Obstructive Sleep Apnea. Oral Maxillofac Surg Clin North Am 7:327-336, 1995 24. Li KK, Troell RJ, Riley RW, et al: Uvulopalatopharyngoplasty, maxillomandibular advancement, and the velopharynx. Laryngoscope 111:1075-1078, 2001 25. Li KK, Riley RW, Powell NB, et al: Maxillomandibular advancement for persistent obstructive sleep apnea after phase I surgery in patients without maxillomandibular deficiency. Laryngoscope 110:1684-1688, 2000 26. Goh YH, Lim KA: Modified maxillomandibular advancement for the treatment of obstructive sleep apnea: A preliminary report. Laryngoscope 113:15771582, 2003
27. Solow B, Skov S, Ovesen J, et al: Airway dimension and head posture in obstructive sleep apnoea. Eur J Orthod 18:571-579, 1996 28. Fairburn SC, Waite PD, Vilos G, et al: Three-dimensional changes in upper airways of patients with obstructive sleep apnea following maxillomandibular advancement. J Oral Maxillofac Surg 65:6-12, 2007 29. Schipper H, Clinch JJ, Olweny CLM: Quality of life studies: Definitions and conceptual issues, In Spilker B (ed): Quality of Life and Pharmacoeconomics in Clinical Trials (ed 2). Philadelphia, PA, Lippincott-Raven, 1996, pp 11-23 30. Woodson BT, Steward DL, Weaver EM, et al: A randomized trial of temperature-controlled radiofrequency, continuous positive airway pressure, and placebo for obstructive sleep apnea syndrome. Otolaryngol Head Neck Surg 128:848-861, 2003 31. Walker-Engstrom ML, Wilhelmsson B, Tegelberg A, et al: Quality of life assessment of treatment with dental appliance or UPPP in patients with mild to moderate obstructive sleep apnoea: A prospective randomized 1-year follow-up study. J Sleep Res 9:303-308, 2000 32. 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