- Email: [email protected]
Maxillomandibular advancement for obstructive sleep apnea
Author's Accepted Manuscript
Maxillomandibular advancement for obstructive sleep apnea Rachel Uppgaard-Penaz Templeton DMD
DDS,
Robert
Bruce
www.techgiendoscopy.com
PII: DOI: Reference:
S1043-1810(15)00081-0 http://dx.doi.org/10.1016/j.otot.2015.08.004 YOTOT686
To appear in:
Operative Techniques in Otolaryngology
Cite this article as: Rachel Uppgaard-Penaz DDS, Robert Bruce Templeton DMD, Maxillomandibular advancement for obstructive sleep apnea, Operative Techniques in Otolaryngology, http://dx.doi.org/10.1016/j.otot.2015.08.004 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Title Page
Maxillomandibular Advancement for Obstructive Sleep Apnea
1. Rachel Uppgaard-Penaz, DDS, Resident, Oral and Maxillofacial Surgery, University of Minnesota, Minneapolis, MN
Robert Bruce Templeton, DMD, Chief of Dentistry and Oral and Maxillofacial Surgery, Minneapolis VA Medical Center, Minneapolis, MN
2. Minneapolis VA Medical Center
3. No outside funding was used to support this paper
4. R Uppgaard-Penaz, 2U Dental, One Veteran’s Drive, Minneapolis, MN 55417, phone: 612-467-1946, fax: 612-727-5669, [email protected]
Abstract:
Objective: Surgical technique for maxillomandibular advancement to improve obstructive sleep apnea will be discussed in this article.
Findings: Surgically advancing the maxillomandibular complex by at least 1 cm provides tension on the soft tissues in the airway from the soft palate to the base of the tongue, widening the pharynx both in anterioposterior dimension, but most importantly laterally. The tissues are no longer able to collapse and obstruct the pharynx. Post-operative polysomnography in patients who have maxillomandibular advancement is comparable to those patients using CPAP therapy appropriately.
Conclusion: Primary surgical maxillomandibular advancement is highly efficacious. More long-term studies are needed for this validating this valuable surgical alternative to CPAP therapy.
Surgical management of obstructive sleep apnea (OSA) via maxillomandibular advancement (MMA) shows great promise for success in many patients with OSA. In the absence of maxillomandibular hypoplasia, success rates as high as 92% have been reported with MMA for OSA1. MMA has been described as the most successful surgical therapy to date, with post-op polysomnography at a comparable level to that during CPAP therapy, which has been considered the gold standard for treatment for OSA2,3.
As with other surgical therapies, thorough pre-surgical planning is crucial to ensure success. Taking into consideration different variables that may affect the outcome is essential. Some of the factors that have been described as having a significant effect on outcome include body mass index, the amount of skeletal advancement that can be performed, significant weight gain post-operatively (5% or greater increase in weight post-operatively could have a recurrence), and skeletal relapse 3 MMA works via widening the pharynx, especially in a lateral dimension3. This widening occurs from the soft palate to the base of the tongue. It provides tension on the soft tissues which previously may have had laxity, promoting collapsibility. The now tense tissues are no longer able to collapse and obstruct the pharynx. The mandibular advancement is most important therapeutic maneuver given that it will further open up the hypopharynx2. The limiting factor with MMA is usually the distance that the maxilla can be advanced, which is limited by the soft tissue1. Figure 1 illustrates the airway widening.
MMA may be performed after other surgical procedures have been tried, such as uvulopalatopharyngoplasty or genioglossus advancement, or MMA may be selected as the primary treatment2,3. Primary treatment with MMA is most likely to provide the most benefit in patients who have severe OSA with a deficient maxillomandibular complex as well as limited excess pharyngeal and tonsillar soft tissue3.
As with any surgical procedure, the surgeon should have a frank discussion with the patient preoperatively regarding potential complications. The most profound complication is that of inferior alveolar nerve paresthesia, which is seen in nearly 100% of cases in which a bilateral sagittal split ramus osteotomy is performed in the immediate post-operative period. This paresthesia is temporary in the majority of patients, but may be permanent in 12.5-20% of cases2. A superficial wound infection may occur in up to 5% of patients2. Minor changes in the occlusion requiring occlusal equilibration (adjustment by a dentist with minimal changes to tooth morphology) is seen in up to 44% of cases2. Hardware may fail and require removal in approximately 2.5%2. Temporomandibular disorders may develop in 2.5% 2. Altered facial esthetics from advancement of the maxillomandibular complex is a concept that the patient should be made aware of—however this is usually not a change that is bothersome to the patients as their tissues are stretched and supported by the underlying bony changes. It has been reported that one half feel that they appear more attractive following MMA3.
Early on, nasal regurgitation of fluids may be seen in patients, although temporary and patients do not have persistent velopharyngeal insufficiency 2,3. Surgical relapse may occur and may be immediate or delayed 4. Non-union of the osteotomies is also a possibility, although rare. Fortunately, in the majority of cases, the improvements are long-term, even with aging and minimal weight gain5. Patients should be warned that significant weight gain may result in worsening of OSA5. With maxillary surgery, there is a risk of bleeding complications4. This would commonly occur from trauma to the greater palatine vessels. In addition, there is the possibility of ischemic necrosis of the maxilla, although this is uncommon 3. Every attempt should be made to preserve the greater palatine vessels. Airway embarrassment post-operatively is not commonly reported 6. With MMA this is very low risk, compared to other surgical procedures for OSA 6. MMA should be performed separately from
intrapharyngeal procedures to reduce the risk of UA embarrassment, given that the airway may be difficult to manage in the setting of maxillomandibular fixation that is required for MMA1.
Another issue that needs to be discussed with patients pre-operatively is the definition of surgical success. A cure for OSA via MMA would be unlikely as OSA is a chronic disease process, but if the criteria for success is respiratory disturbance index (RDI) and apnea-hypopnea index (AHI) of less than 10/hour, then the success rates of 65% and 97% may be described7,8. In order to achieve success, the maxillomandibular complex needs to be advanced at least 10mm2. The patients that will experience the most success from MMA are those who have an airway obstruction at the base of the tongue and soft palate3.
Presurgical planning requires imaging which at minimum should include an orthopantomogram film and a lateral cephalogram. The lateral cephalogram should reveal hypopharyngeal narrowing (less than 9mm) in order to consider MMA1. In addition, models of the teeth should be taken to provide a threedimensional representation of the occlusion and to perform “model surgery”. The models of the teeth should be mounted with jaw relations on an articulator, and surgical moves can be created in stone models. The advantage that model surgery provides is that it provides a projection of what moves will be necessary in three dimensions4. There is always the option of obtaining a CT scan and working with virtual planning technology.
Finally, before proceeding with surgery, it is important to differentiate between orthognathic or telegnathic surgery as first defined by Moore. In orthognathic surgery, the dentition will be appropriately aligned with the fixation of the maxilla and mandible in order to correct a dentofacial deformity. Only one jaw may need to be moved (in the case of OSA patients, the mandible). This often requires careful planning with an Orthodontist to ensure that the dentition is leveled and aligned so that it can be moved surgically and the patient ultimately has an ideal occlusion. In telegnathic surgery, the
objective is to enlarge the airway via movement of the jaws. Often both jaws will be moved together using pre-existing occlusion without orthodontic therapy. Frequently the jaws are rotated together in counterclockwise fashion in addition to advancing both jaws anteriorly.
Prior to surgery, it is important to discuss the case with the Anesthesia team. In order to maintain the occlusion, having a nasoendotracheal tube placed provides adequate access without compromising the airway when placing the patient into maxillomandibular fixation. Often the airway is more challenging for the Anesthesia team to manipulate given the tissues that easily obstruct the airway. In extreme cases, an awake fiberoptic nasal intubation may provide a safe, effective means to secure the airway intraoperatively. In discussion with the Anesthesia team, it should be noted that maxillary advancement procedures may cause significant bleeding. Hypotensive anesthesia should be considered prior to maxillary downfracture to reduce bleeding. In young healthy patients, mean arterial pressures of 50-65 mm Hg is appropriate9. In patients with multiple medical comorbidities, this may need to be higher to ensure adequate perfusion of other organs.
Surgical Technique: Maxillary Advancement via LeFort I osteotomy:
Prior to initiating incisions and osteotomies, if the patient does not have orthodontic appliance in place, arch bars may be placed so that the surgeon is able to wire the surgical guides to the teeth and place patient into maxillomandibular fixation with elastics following surgery. Some surgeons will avoid use of surgical guides entirely and will place the patient into maxillomandibular fixation for the entire case.
Local anesthesia with vasoconstrictor is administered via local infiltration in the maxilla and via bilateral inferior alveolar nerve and long buccal nerve blocks in the mandible. Additional local infiltration may be used in the region of the mandibular incisions.
Incision: Create incision in the vestibule above the marginal gingiva at approximately the level of the apices of the maxillary teeth. This may be created with a blade or with electrocautery. Extend this horizontal incision from first molar to opposite first molar region, through periosteum. Reflect a full thickness mucoperiosteal flap via periosteal elevator to expose the anterior and lateral maxillary walls, the zygomaticomaxillary suture, and the zygomatic buttress. It is important to identify the infraorbital nerves. Extend posteriorly to the pterygoid plates, with attention to dissecting more inferiorly to avoid vascular structures. Care should be used throughout dissection to avoid perforating the periosteum, which could expose the buccal fat pad. Exposure of the buccal fat pad may make visualization and retraction more difficult. Attention should then be turned to the nasal mucosa. Using a freer elevator, elevate nasal mucosa carefully from the lateral nasal walls (at least 1 cm up), as well as from the nasal floor and nasal crest4. The anterior nasal spine should be fully visualized. During down-fracture of the maxilla, it is helpful if all the nasal mucosa has been adequately elevated. If it has not, it may require further dissection after the osteotomies have been performed.
Osteotomies: It may be helpful to place initial reference cuts using a fissure bur with copious irrigation, consider placing these lines above the canines and first molars, using caution to ensure that the reference lines are superior to the apices of the roots. Using a reciprocating saw or a fissure bur, a horizontal osteotomy is created from the zygomatic buttress to piriform rim, connecting the reference lines. Extend osteotomies posteriorly and inferiorly toward the pterygomaxillary junction. The anterior cut should extend through the piriform rim and anterior lateral nasal wall.
The osteotomies should be
(approximately) at least 5mm above the apices of the teeth. Nasal mucosa is retracted to protect the mucosa during osteotomies. A nasal osteotome may be used in a downward posterior fashion starting at the anterior nasal spine to separate the septum from the nasal crest. Use osteotomes in the pterygomaxillary junction, and in the lateral nasal walls. Do not extend beyond 20mm posteriorly as the
descending palatine vessels may be transected4. Curved or pterygoid osteotomes may be used anteriorly, inferiorly and medially between the maxillary tuberosity and the pterygoid plates.
Check with the anesthesiologist that the patient is hypotensive (usually keep MAPs ~55 during this portion of the procedure if the patient is relatively healthy—permissive hypotension, otherwise the patient may require a higher MAP). Inform the Anesthesia team that the patient may experience rebound hypertension. Then the surgeon manually down-fractures the maxilla by placing pressure with his/her hand in the anterior maxilla and rotating the maxilla down in a clockwise fashion. If the maxilla does not down-fracture easily, then further work with the osteotomes may be indicated to ensure complete separation. At this point, hemorrhage may occur and may require packing the posterior maxilla with sponges for hemostasis and use of cautery. Ultimately, if hemostasis cannot be attained the descending palatine vessels may need to be identified and ligated. Some surgeons prefer to ligate the decending palatine neurovascular bundle in all cases, however, preserving the descending palatine vessels may be beneficial for maintaining blood flow of the maxilla. The nasal mucoperiosteum will need to be completely elevated if it has not been yet. Once the maxilla has been down-fractured, the surgeon may use Tessier mobilizers on the posterior maxilla to obtain complete separation from the pterygoid plates. The maxilla may be gently rotated in all directions using the Tessier mobilizers or Rowe forceps 10. The maxilla should be very mobile (complete mobilization: 1-1.5 cm in any direction)4. The Tessier mobilizers or another traction device should be then used to gently and slowly stretch the maxilla anteriorly, while carefully observing the maxillary tissues for any change in perfusion.
Use a bur with copious irrigation or rongeurs to remove any interference in the line of the osteotomies. This is especially important if the maxilla is going to be superiorly impacted. Areas that are frequently a problem include the pterygoid plates, perpendicular plate of the palatine bone, the lateral nasal walls (especially posteriorly), and the lateral maxillary sinus walls posterior to the second molar (tuberosity
region). Removing part of the cartilaginous nasal septum may be necessary so that the nasal septum does not buckle under pressure4. Gentle digital pressure should be sufficient to position the maxilla in the planned final position.
The intermediate occlusal splint is then wired to the maxillary and mandibular dentition. The mandibular condyles are seated in the fossa superiorly and anteriorly bilaterally, then the maxillomandibular complex is rotated until the vertical position is adequate and this guides the maxilla into the appropriate planned position. Check for any bony interferences. Rigid fixation of the maxilla is achieved, typically with 2.0mm four-hole plates ( Figure 2).
The surgeon may consider contouring the piriform aperature with a pear shaped bur to improve airflow as well. Cinch sutures are often used in orthognathic surgery to reapproximate the nasal base. This technique may be used judiciously with MMA for OSA as well to help with facial balance. However, it is important not to significantly narrow the nasal base in the OSA patient. If it is determined that a cinch suture would help with nasal base position, then drill a small osteotomy in the anterior nasal spine. Use 2-0 PDS to cinch the alar base tissue from left and right sides to the maxilla, threading the suture through the osteotomy in the anterior nasal spine. Check the appearance of the nasal base while tightening the suture. The surgical site should be thoroughly irrigated and examined for any debris. Now closure can be initiated. Chromic gut or vicryl suture may be used to perform a V-Y closure of the mucosa. The V-Y closure is important for preserving the length of the upper lip, which could otherwise be shortened by this procedure, contributing to a poor cosmetic outcome. The intermediate surgical guide may be removed and replaced by the final surgical guide, which will help position the mandible and which will also provide the patient with guidance as to where to bite while awaiting full return of sensation in the mandibular teeth. Prior to making the osteotomies in the mandible, the final surgical guide should be wired to the maxillary teeth only. At the conclusion of the procedure when the patient
is extubated, merocel packs may be placed bilaterally in the nasal passageways to help with hemostasis if needed.
Mandibular Advancement:
The most common mandibular advancement procedure is the bilateral sagittal split ramus osteotomy with advancement of the mandible, followed by fixation with plates or lag screws. Pre-operatively, it is important to palpate the ramus of the mandible to ensure that there is sufficient width to the mandibular ramus in a lateral-medial dimension to create an adequate split.
A vestibular incision is created through the mucosa lateral to the external oblique ridge, extending from halfway to two-thirds of the way (superiorly) between the maxillary and mandibular dentition extending approximately to the distal of the first molar. The periosteum is reflected via full thickness mucoperiosteal flap, and dissection with a periosteal elevator, is completed to expose the medial aspect of the posterior body/anterior ramus exposing the lingula and the inferior alveolar neurovascular bundle. Continue the dissection subperiosteally to elevate the temporalis and periosteum from the anterior ramus.
Osteotomies: During the osteotomies, it is very important to have retractors in place subperiosteally to protect the soft tissues. These osteotomies may be created using a reciprocating saw, Lindemann bur or piezoelectric handpiece and should not extend beyond the cortex. Cut perpendicular to the medial cortex, just superior to the lingula using caution to preserve the IAN. Continue the corticotomy along the external oblique ridge, extending laterally to the first molar region. Caution should be used when creating these corticotomies to ensure that they are sufficiently lateral to avoid the roots of the teeth. A vertical osteotomy is created in the first molar region and extends to the inferior border of the mandible (Figure 3). Carefully use osteotomes to separate the two segments. It is crucial to use caution at this
juncture to ensure that the cuts are completed and that the osteotomes are managed carefully to avoid an unfavorable split. Visualize the inferior alveolar neurovascular bundle to ensure that the inferior alveolar nerve is intact. If it has been severed, it may be repaired at this time, however, this should not occur if the osteotomies were appropriately made. The J stripper may be used to free up the periosteum and pterygomasseteric sling from the medial aspect of the proximal segment to ensure adequate mobilization.
At this time the distal segment of the mandible is placed in occlusion with the final surgical guide and the mandibular teeth are wired to the maxillary teeth. The position of the teeth should be checked to ensure that the mandibular distal segment is completely interdigitating with the surgical guide to ensure good post-operative occlusion. Position the condyles superiorly in the glenoid fossae bilaterally. Now that all segments are appropriately positioned, lag screws, bicortical screws, or plates and monocortical screws may be used for fixation. A small incision in the skin and use of a trochar for placement of the lag or bicortical screws may be indicated for access. The patient is released from the wire maxillomandibular fixation and the occlusion is checked to ensure that the fixation is appropriate. The surgical site is irrigated and all incisions are closed with 3-0 chromic gut or vicryl sutures. Skin incisions if needed should be closed as well. Orthodontic elastics may be use to guide the patient into maximum intercuspation of the maxillary and mandibular teeth if the patient has braces. Otherwise, if the patient does not have orthodontic appliances, arch bars placed at the beginning of the case may be utilized.
Many surgeons place the patients into post-operative maxillomandibular fixation with heavy elastics on the arch bars or orthodontic appliances. It has been suggested that if the maxillomandibular advancement is greater than or equal to 7mm, maxillomandibular fixation should be used 4.
Genial Advancement:
Maxillomandibular advancement may be coupled with a genial advancement done in routine fashion. A vestibular incision is made in mucosa down to the periosteum through the mentalis muscle in the anterior mandible from canine to opposite canine. The periosteum is reflected to the inferior border of the mandible. The mental nerve is identified and skeletonized bilaterally. The midline of the planned segment of bone to be advanced should be marked to ensure that the midline is not changed, creating an asymmetry. A fissure bur or reciprocating saw with chilled saline irrigation may be used to make the osteotomy. Osteotomies should be made at least 5mm below the apices of the teeth and should extend inferiorly as the osteotomy progresses posteriorly. Creating reference lines prior to making the osteotomy may prove helpful in osteotomy placement. In the anterior mandible the osteotomy should be superior to the genial tubercles. The osteotomy should extend inferiorly to the mental nerve. While some surgeons prefer to make vertical cuts and advance a trapezoid shaped segment of bone, this can create a step-off deformity that may be visible or palpable. Making one smooth osteotomy that is of the greatest height anteriorly and slowly tapers posteriorly results in a smooth inferior border of the mandible when the segment is advanced. Plates and monocortical screws or lag screws may be used to provide fixation to the pre-determined amount of advancement. The mentalis muscle is then resuspended to the periosteum using 2-0 vicryl. The surgical site is irrigated and closed with either vicryl or chromic gut suture.
Post-Operative Management:
Post-operatively, placement of foam tape on the mandible or use of a compression bandage is helpful to provide compression and support to the mentalis.
The patient should be monitored closely for any
airway complications. Merocel packs, if placed in the nasal passageways, may be removed between post-op day 1-3. Starting on post-op day 1, the patient should perform rinses of the oral cavity with warm salt water as well as 0.12% chlorhexidine. Gentle toothbrushing may start on post-op day 1 as well. The patient will be on a non-chew diet for at least 4-6 weeks.
Conclusions:
MMA is a successful option for management of OSA. Thorough pre-operative planning and discussion of risks with the patient are paramount. Intraoperatively, advancement of the maxillomandibular complex of at least 1cm is important. Rigid fixation with plates and monocortical screws or bicortical screws or lag screws is necessary for stability. Post-operatively, patients should be managed closely and observed for airway obstruction.
References:
1. Prinsell JR. Primary and secondary telegnathic maxillomandibular advancement, with or without adjunctive procedures, for obstructive sleep apnea in adults: a literature review and treatment recommendations. J Oral Maxillofac Surg 2012; 70:1659-1677. 2. Pirklbauer K, Russmueller G, Stiebellehner L, Nell C, Sinko K, Millesi G, Klug C. Maxillomandibular advancement for treatment of obstructive sleep apnea syndrome: a systematic review. J Oral Maxillofac Surg 69:e165-e176 3. Li KK. Maxillomandibular advancement for obstructive sleep apnea. J Oral Maxillofac Surg 2011; 69:687-694. 4. Miloro M, Ghali GE, Larsen PE, Waite PD. Peterson’s Principles of Oral and Maxillofacial Surgery. 2nd Ed. Hamilton (Ontario): BC Decker Inc; 2004.
5. Li K, Powell NB, Riley RW, Troell RJ, Guilleinault C. Longterm results of maxillomandibular advancement surgery. Sleep and Breathing 2000; 4(3):137-139 6. Prinsell JR. Maxillomandibular advancement surgery in a site-specific treatment approach for obstructive sleep apnea in 50 consecutive patients. Chest 1999; 16: 1519-1529. 7. Waite PD, Wooten V, Lachner J. Maxillomandibular advancement surgery in 23 patients with obstructive sleep apnea syndrome. J Oral Maxillofac Surg 1989; 47:1256 8. Hochban W, Conradt R, Brandenburg U, HeitmannJ, Peter JH. Surgical maxillofacial treatment of obstructive sleep apnea. Plast Reconstr Surg 1997; 99:619-626. 9. Rodrigo C. Induced hypotension during anesthesia, with special reference to orthognathic surgery. Anest Prog 1995;42:41-58. 10. Boyd SB. Management of obstructive sleep apnea by maxillomandibular advancement. Oral Maxillofacial Surg Clin N Am 2009; 21: 447-457
Captions: Figure 1. Image A demonstrates an airway that is 8mm in anteroposterior dimension, and narrows to 6 mm with a modified Muller maneuver in image B. Genioplasty results in 12mm of anteroposterior dimension in image C, and MMA results in 20mm of anteroposterior dimension in image D (Image A to D from left to right).
Figure 2. Images A illustrates frontal view of LeFort I osteotomy, maxillary advancement and fixations, mandibular advancement, genioplasty and their fixations. Image B illustrates Lateral view of LeFort I osteotomy, maxillary advancement and fixations. Image C illustrates lateral view of mandibular advancement and genioplasty.
Figure 3. Images A–D illustrate incisions and surgical osteotomies for the mandibular advancement.
Figure 2
Figure 3
Maxillomandibular advancement for obstructive sleep apnea Rachel Uppgaard-Penaz Templeton DMD
DDS,
Robert
Bruce
www.techgiendoscopy.com
PII: DOI: Reference:
S1043-1810(15)00081-0 http://dx.doi.org/10.1016/j.otot.2015.08.004 YOTOT686
To appear in:
Operative Techniques in Otolaryngology
Cite this article as: Rachel Uppgaard-Penaz DDS, Robert Bruce Templeton DMD, Maxillomandibular advancement for obstructive sleep apnea, Operative Techniques in Otolaryngology, http://dx.doi.org/10.1016/j.otot.2015.08.004 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Title Page
Maxillomandibular Advancement for Obstructive Sleep Apnea
1. Rachel Uppgaard-Penaz, DDS, Resident, Oral and Maxillofacial Surgery, University of Minnesota, Minneapolis, MN
Robert Bruce Templeton, DMD, Chief of Dentistry and Oral and Maxillofacial Surgery, Minneapolis VA Medical Center, Minneapolis, MN
2. Minneapolis VA Medical Center
3. No outside funding was used to support this paper
4. R Uppgaard-Penaz, 2U Dental, One Veteran’s Drive, Minneapolis, MN 55417, phone: 612-467-1946, fax: 612-727-5669, [email protected]
Abstract:
Objective: Surgical technique for maxillomandibular advancement to improve obstructive sleep apnea will be discussed in this article.
Findings: Surgically advancing the maxillomandibular complex by at least 1 cm provides tension on the soft tissues in the airway from the soft palate to the base of the tongue, widening the pharynx both in anterioposterior dimension, but most importantly laterally. The tissues are no longer able to collapse and obstruct the pharynx. Post-operative polysomnography in patients who have maxillomandibular advancement is comparable to those patients using CPAP therapy appropriately.
Conclusion: Primary surgical maxillomandibular advancement is highly efficacious. More long-term studies are needed for this validating this valuable surgical alternative to CPAP therapy.
Surgical management of obstructive sleep apnea (OSA) via maxillomandibular advancement (MMA) shows great promise for success in many patients with OSA. In the absence of maxillomandibular hypoplasia, success rates as high as 92% have been reported with MMA for OSA1. MMA has been described as the most successful surgical therapy to date, with post-op polysomnography at a comparable level to that during CPAP therapy, which has been considered the gold standard for treatment for OSA2,3.
As with other surgical therapies, thorough pre-surgical planning is crucial to ensure success. Taking into consideration different variables that may affect the outcome is essential. Some of the factors that have been described as having a significant effect on outcome include body mass index, the amount of skeletal advancement that can be performed, significant weight gain post-operatively (5% or greater increase in weight post-operatively could have a recurrence), and skeletal relapse 3 MMA works via widening the pharynx, especially in a lateral dimension3. This widening occurs from the soft palate to the base of the tongue. It provides tension on the soft tissues which previously may have had laxity, promoting collapsibility. The now tense tissues are no longer able to collapse and obstruct the pharynx. The mandibular advancement is most important therapeutic maneuver given that it will further open up the hypopharynx2. The limiting factor with MMA is usually the distance that the maxilla can be advanced, which is limited by the soft tissue1. Figure 1 illustrates the airway widening.
MMA may be performed after other surgical procedures have been tried, such as uvulopalatopharyngoplasty or genioglossus advancement, or MMA may be selected as the primary treatment2,3. Primary treatment with MMA is most likely to provide the most benefit in patients who have severe OSA with a deficient maxillomandibular complex as well as limited excess pharyngeal and tonsillar soft tissue3.
As with any surgical procedure, the surgeon should have a frank discussion with the patient preoperatively regarding potential complications. The most profound complication is that of inferior alveolar nerve paresthesia, which is seen in nearly 100% of cases in which a bilateral sagittal split ramus osteotomy is performed in the immediate post-operative period. This paresthesia is temporary in the majority of patients, but may be permanent in 12.5-20% of cases2. A superficial wound infection may occur in up to 5% of patients2. Minor changes in the occlusion requiring occlusal equilibration (adjustment by a dentist with minimal changes to tooth morphology) is seen in up to 44% of cases2. Hardware may fail and require removal in approximately 2.5%2. Temporomandibular disorders may develop in 2.5% 2. Altered facial esthetics from advancement of the maxillomandibular complex is a concept that the patient should be made aware of—however this is usually not a change that is bothersome to the patients as their tissues are stretched and supported by the underlying bony changes. It has been reported that one half feel that they appear more attractive following MMA3.
Early on, nasal regurgitation of fluids may be seen in patients, although temporary and patients do not have persistent velopharyngeal insufficiency 2,3. Surgical relapse may occur and may be immediate or delayed 4. Non-union of the osteotomies is also a possibility, although rare. Fortunately, in the majority of cases, the improvements are long-term, even with aging and minimal weight gain5. Patients should be warned that significant weight gain may result in worsening of OSA5. With maxillary surgery, there is a risk of bleeding complications4. This would commonly occur from trauma to the greater palatine vessels. In addition, there is the possibility of ischemic necrosis of the maxilla, although this is uncommon 3. Every attempt should be made to preserve the greater palatine vessels. Airway embarrassment post-operatively is not commonly reported 6. With MMA this is very low risk, compared to other surgical procedures for OSA 6. MMA should be performed separately from
intrapharyngeal procedures to reduce the risk of UA embarrassment, given that the airway may be difficult to manage in the setting of maxillomandibular fixation that is required for MMA1.
Another issue that needs to be discussed with patients pre-operatively is the definition of surgical success. A cure for OSA via MMA would be unlikely as OSA is a chronic disease process, but if the criteria for success is respiratory disturbance index (RDI) and apnea-hypopnea index (AHI) of less than 10/hour, then the success rates of 65% and 97% may be described7,8. In order to achieve success, the maxillomandibular complex needs to be advanced at least 10mm2. The patients that will experience the most success from MMA are those who have an airway obstruction at the base of the tongue and soft palate3.
Presurgical planning requires imaging which at minimum should include an orthopantomogram film and a lateral cephalogram. The lateral cephalogram should reveal hypopharyngeal narrowing (less than 9mm) in order to consider MMA1. In addition, models of the teeth should be taken to provide a threedimensional representation of the occlusion and to perform “model surgery”. The models of the teeth should be mounted with jaw relations on an articulator, and surgical moves can be created in stone models. The advantage that model surgery provides is that it provides a projection of what moves will be necessary in three dimensions4. There is always the option of obtaining a CT scan and working with virtual planning technology.
Finally, before proceeding with surgery, it is important to differentiate between orthognathic or telegnathic surgery as first defined by Moore. In orthognathic surgery, the dentition will be appropriately aligned with the fixation of the maxilla and mandible in order to correct a dentofacial deformity. Only one jaw may need to be moved (in the case of OSA patients, the mandible). This often requires careful planning with an Orthodontist to ensure that the dentition is leveled and aligned so that it can be moved surgically and the patient ultimately has an ideal occlusion. In telegnathic surgery, the
objective is to enlarge the airway via movement of the jaws. Often both jaws will be moved together using pre-existing occlusion without orthodontic therapy. Frequently the jaws are rotated together in counterclockwise fashion in addition to advancing both jaws anteriorly.
Prior to surgery, it is important to discuss the case with the Anesthesia team. In order to maintain the occlusion, having a nasoendotracheal tube placed provides adequate access without compromising the airway when placing the patient into maxillomandibular fixation. Often the airway is more challenging for the Anesthesia team to manipulate given the tissues that easily obstruct the airway. In extreme cases, an awake fiberoptic nasal intubation may provide a safe, effective means to secure the airway intraoperatively. In discussion with the Anesthesia team, it should be noted that maxillary advancement procedures may cause significant bleeding. Hypotensive anesthesia should be considered prior to maxillary downfracture to reduce bleeding. In young healthy patients, mean arterial pressures of 50-65 mm Hg is appropriate9. In patients with multiple medical comorbidities, this may need to be higher to ensure adequate perfusion of other organs.
Surgical Technique: Maxillary Advancement via LeFort I osteotomy:
Prior to initiating incisions and osteotomies, if the patient does not have orthodontic appliance in place, arch bars may be placed so that the surgeon is able to wire the surgical guides to the teeth and place patient into maxillomandibular fixation with elastics following surgery. Some surgeons will avoid use of surgical guides entirely and will place the patient into maxillomandibular fixation for the entire case.
Local anesthesia with vasoconstrictor is administered via local infiltration in the maxilla and via bilateral inferior alveolar nerve and long buccal nerve blocks in the mandible. Additional local infiltration may be used in the region of the mandibular incisions.
Incision: Create incision in the vestibule above the marginal gingiva at approximately the level of the apices of the maxillary teeth. This may be created with a blade or with electrocautery. Extend this horizontal incision from first molar to opposite first molar region, through periosteum. Reflect a full thickness mucoperiosteal flap via periosteal elevator to expose the anterior and lateral maxillary walls, the zygomaticomaxillary suture, and the zygomatic buttress. It is important to identify the infraorbital nerves. Extend posteriorly to the pterygoid plates, with attention to dissecting more inferiorly to avoid vascular structures. Care should be used throughout dissection to avoid perforating the periosteum, which could expose the buccal fat pad. Exposure of the buccal fat pad may make visualization and retraction more difficult. Attention should then be turned to the nasal mucosa. Using a freer elevator, elevate nasal mucosa carefully from the lateral nasal walls (at least 1 cm up), as well as from the nasal floor and nasal crest4. The anterior nasal spine should be fully visualized. During down-fracture of the maxilla, it is helpful if all the nasal mucosa has been adequately elevated. If it has not, it may require further dissection after the osteotomies have been performed.
Osteotomies: It may be helpful to place initial reference cuts using a fissure bur with copious irrigation, consider placing these lines above the canines and first molars, using caution to ensure that the reference lines are superior to the apices of the roots. Using a reciprocating saw or a fissure bur, a horizontal osteotomy is created from the zygomatic buttress to piriform rim, connecting the reference lines. Extend osteotomies posteriorly and inferiorly toward the pterygomaxillary junction. The anterior cut should extend through the piriform rim and anterior lateral nasal wall.
The osteotomies should be
(approximately) at least 5mm above the apices of the teeth. Nasal mucosa is retracted to protect the mucosa during osteotomies. A nasal osteotome may be used in a downward posterior fashion starting at the anterior nasal spine to separate the septum from the nasal crest. Use osteotomes in the pterygomaxillary junction, and in the lateral nasal walls. Do not extend beyond 20mm posteriorly as the
descending palatine vessels may be transected4. Curved or pterygoid osteotomes may be used anteriorly, inferiorly and medially between the maxillary tuberosity and the pterygoid plates.
Check with the anesthesiologist that the patient is hypotensive (usually keep MAPs ~55 during this portion of the procedure if the patient is relatively healthy—permissive hypotension, otherwise the patient may require a higher MAP). Inform the Anesthesia team that the patient may experience rebound hypertension. Then the surgeon manually down-fractures the maxilla by placing pressure with his/her hand in the anterior maxilla and rotating the maxilla down in a clockwise fashion. If the maxilla does not down-fracture easily, then further work with the osteotomes may be indicated to ensure complete separation. At this point, hemorrhage may occur and may require packing the posterior maxilla with sponges for hemostasis and use of cautery. Ultimately, if hemostasis cannot be attained the descending palatine vessels may need to be identified and ligated. Some surgeons prefer to ligate the decending palatine neurovascular bundle in all cases, however, preserving the descending palatine vessels may be beneficial for maintaining blood flow of the maxilla. The nasal mucoperiosteum will need to be completely elevated if it has not been yet. Once the maxilla has been down-fractured, the surgeon may use Tessier mobilizers on the posterior maxilla to obtain complete separation from the pterygoid plates. The maxilla may be gently rotated in all directions using the Tessier mobilizers or Rowe forceps 10. The maxilla should be very mobile (complete mobilization: 1-1.5 cm in any direction)4. The Tessier mobilizers or another traction device should be then used to gently and slowly stretch the maxilla anteriorly, while carefully observing the maxillary tissues for any change in perfusion.
Use a bur with copious irrigation or rongeurs to remove any interference in the line of the osteotomies. This is especially important if the maxilla is going to be superiorly impacted. Areas that are frequently a problem include the pterygoid plates, perpendicular plate of the palatine bone, the lateral nasal walls (especially posteriorly), and the lateral maxillary sinus walls posterior to the second molar (tuberosity
region). Removing part of the cartilaginous nasal septum may be necessary so that the nasal septum does not buckle under pressure4. Gentle digital pressure should be sufficient to position the maxilla in the planned final position.
The intermediate occlusal splint is then wired to the maxillary and mandibular dentition. The mandibular condyles are seated in the fossa superiorly and anteriorly bilaterally, then the maxillomandibular complex is rotated until the vertical position is adequate and this guides the maxilla into the appropriate planned position. Check for any bony interferences. Rigid fixation of the maxilla is achieved, typically with 2.0mm four-hole plates ( Figure 2).
The surgeon may consider contouring the piriform aperature with a pear shaped bur to improve airflow as well. Cinch sutures are often used in orthognathic surgery to reapproximate the nasal base. This technique may be used judiciously with MMA for OSA as well to help with facial balance. However, it is important not to significantly narrow the nasal base in the OSA patient. If it is determined that a cinch suture would help with nasal base position, then drill a small osteotomy in the anterior nasal spine. Use 2-0 PDS to cinch the alar base tissue from left and right sides to the maxilla, threading the suture through the osteotomy in the anterior nasal spine. Check the appearance of the nasal base while tightening the suture. The surgical site should be thoroughly irrigated and examined for any debris. Now closure can be initiated. Chromic gut or vicryl suture may be used to perform a V-Y closure of the mucosa. The V-Y closure is important for preserving the length of the upper lip, which could otherwise be shortened by this procedure, contributing to a poor cosmetic outcome. The intermediate surgical guide may be removed and replaced by the final surgical guide, which will help position the mandible and which will also provide the patient with guidance as to where to bite while awaiting full return of sensation in the mandibular teeth. Prior to making the osteotomies in the mandible, the final surgical guide should be wired to the maxillary teeth only. At the conclusion of the procedure when the patient
is extubated, merocel packs may be placed bilaterally in the nasal passageways to help with hemostasis if needed.
Mandibular Advancement:
The most common mandibular advancement procedure is the bilateral sagittal split ramus osteotomy with advancement of the mandible, followed by fixation with plates or lag screws. Pre-operatively, it is important to palpate the ramus of the mandible to ensure that there is sufficient width to the mandibular ramus in a lateral-medial dimension to create an adequate split.
A vestibular incision is created through the mucosa lateral to the external oblique ridge, extending from halfway to two-thirds of the way (superiorly) between the maxillary and mandibular dentition extending approximately to the distal of the first molar. The periosteum is reflected via full thickness mucoperiosteal flap, and dissection with a periosteal elevator, is completed to expose the medial aspect of the posterior body/anterior ramus exposing the lingula and the inferior alveolar neurovascular bundle. Continue the dissection subperiosteally to elevate the temporalis and periosteum from the anterior ramus.
Osteotomies: During the osteotomies, it is very important to have retractors in place subperiosteally to protect the soft tissues. These osteotomies may be created using a reciprocating saw, Lindemann bur or piezoelectric handpiece and should not extend beyond the cortex. Cut perpendicular to the medial cortex, just superior to the lingula using caution to preserve the IAN. Continue the corticotomy along the external oblique ridge, extending laterally to the first molar region. Caution should be used when creating these corticotomies to ensure that they are sufficiently lateral to avoid the roots of the teeth. A vertical osteotomy is created in the first molar region and extends to the inferior border of the mandible (Figure 3). Carefully use osteotomes to separate the two segments. It is crucial to use caution at this
juncture to ensure that the cuts are completed and that the osteotomes are managed carefully to avoid an unfavorable split. Visualize the inferior alveolar neurovascular bundle to ensure that the inferior alveolar nerve is intact. If it has been severed, it may be repaired at this time, however, this should not occur if the osteotomies were appropriately made. The J stripper may be used to free up the periosteum and pterygomasseteric sling from the medial aspect of the proximal segment to ensure adequate mobilization.
At this time the distal segment of the mandible is placed in occlusion with the final surgical guide and the mandibular teeth are wired to the maxillary teeth. The position of the teeth should be checked to ensure that the mandibular distal segment is completely interdigitating with the surgical guide to ensure good post-operative occlusion. Position the condyles superiorly in the glenoid fossae bilaterally. Now that all segments are appropriately positioned, lag screws, bicortical screws, or plates and monocortical screws may be used for fixation. A small incision in the skin and use of a trochar for placement of the lag or bicortical screws may be indicated for access. The patient is released from the wire maxillomandibular fixation and the occlusion is checked to ensure that the fixation is appropriate. The surgical site is irrigated and all incisions are closed with 3-0 chromic gut or vicryl sutures. Skin incisions if needed should be closed as well. Orthodontic elastics may be use to guide the patient into maximum intercuspation of the maxillary and mandibular teeth if the patient has braces. Otherwise, if the patient does not have orthodontic appliances, arch bars placed at the beginning of the case may be utilized.
Many surgeons place the patients into post-operative maxillomandibular fixation with heavy elastics on the arch bars or orthodontic appliances. It has been suggested that if the maxillomandibular advancement is greater than or equal to 7mm, maxillomandibular fixation should be used 4.
Genial Advancement:
Maxillomandibular advancement may be coupled with a genial advancement done in routine fashion. A vestibular incision is made in mucosa down to the periosteum through the mentalis muscle in the anterior mandible from canine to opposite canine. The periosteum is reflected to the inferior border of the mandible. The mental nerve is identified and skeletonized bilaterally. The midline of the planned segment of bone to be advanced should be marked to ensure that the midline is not changed, creating an asymmetry. A fissure bur or reciprocating saw with chilled saline irrigation may be used to make the osteotomy. Osteotomies should be made at least 5mm below the apices of the teeth and should extend inferiorly as the osteotomy progresses posteriorly. Creating reference lines prior to making the osteotomy may prove helpful in osteotomy placement. In the anterior mandible the osteotomy should be superior to the genial tubercles. The osteotomy should extend inferiorly to the mental nerve. While some surgeons prefer to make vertical cuts and advance a trapezoid shaped segment of bone, this can create a step-off deformity that may be visible or palpable. Making one smooth osteotomy that is of the greatest height anteriorly and slowly tapers posteriorly results in a smooth inferior border of the mandible when the segment is advanced. Plates and monocortical screws or lag screws may be used to provide fixation to the pre-determined amount of advancement. The mentalis muscle is then resuspended to the periosteum using 2-0 vicryl. The surgical site is irrigated and closed with either vicryl or chromic gut suture.
Post-Operative Management:
Post-operatively, placement of foam tape on the mandible or use of a compression bandage is helpful to provide compression and support to the mentalis.
The patient should be monitored closely for any
airway complications. Merocel packs, if placed in the nasal passageways, may be removed between post-op day 1-3. Starting on post-op day 1, the patient should perform rinses of the oral cavity with warm salt water as well as 0.12% chlorhexidine. Gentle toothbrushing may start on post-op day 1 as well. The patient will be on a non-chew diet for at least 4-6 weeks.
Conclusions:
MMA is a successful option for management of OSA. Thorough pre-operative planning and discussion of risks with the patient are paramount. Intraoperatively, advancement of the maxillomandibular complex of at least 1cm is important. Rigid fixation with plates and monocortical screws or bicortical screws or lag screws is necessary for stability. Post-operatively, patients should be managed closely and observed for airway obstruction.
References:
1. Prinsell JR. Primary and secondary telegnathic maxillomandibular advancement, with or without adjunctive procedures, for obstructive sleep apnea in adults: a literature review and treatment recommendations. J Oral Maxillofac Surg 2012; 70:1659-1677. 2. Pirklbauer K, Russmueller G, Stiebellehner L, Nell C, Sinko K, Millesi G, Klug C. Maxillomandibular advancement for treatment of obstructive sleep apnea syndrome: a systematic review. J Oral Maxillofac Surg 69:e165-e176 3. Li KK. Maxillomandibular advancement for obstructive sleep apnea. J Oral Maxillofac Surg 2011; 69:687-694. 4. Miloro M, Ghali GE, Larsen PE, Waite PD. Peterson’s Principles of Oral and Maxillofacial Surgery. 2nd Ed. Hamilton (Ontario): BC Decker Inc; 2004.
5. Li K, Powell NB, Riley RW, Troell RJ, Guilleinault C. Longterm results of maxillomandibular advancement surgery. Sleep and Breathing 2000; 4(3):137-139 6. Prinsell JR. Maxillomandibular advancement surgery in a site-specific treatment approach for obstructive sleep apnea in 50 consecutive patients. Chest 1999; 16: 1519-1529. 7. Waite PD, Wooten V, Lachner J. Maxillomandibular advancement surgery in 23 patients with obstructive sleep apnea syndrome. J Oral Maxillofac Surg 1989; 47:1256 8. Hochban W, Conradt R, Brandenburg U, HeitmannJ, Peter JH. Surgical maxillofacial treatment of obstructive sleep apnea. Plast Reconstr Surg 1997; 99:619-626. 9. Rodrigo C. Induced hypotension during anesthesia, with special reference to orthognathic surgery. Anest Prog 1995;42:41-58. 10. Boyd SB. Management of obstructive sleep apnea by maxillomandibular advancement. Oral Maxillofacial Surg Clin N Am 2009; 21: 447-457
Captions: Figure 1. Image A demonstrates an airway that is 8mm in anteroposterior dimension, and narrows to 6 mm with a modified Muller maneuver in image B. Genioplasty results in 12mm of anteroposterior dimension in image C, and MMA results in 20mm of anteroposterior dimension in image D (Image A to D from left to right).
Figure 2. Images A illustrates frontal view of LeFort I osteotomy, maxillary advancement and fixations, mandibular advancement, genioplasty and their fixations. Image B illustrates Lateral view of LeFort I osteotomy, maxillary advancement and fixations. Image C illustrates lateral view of mandibular advancement and genioplasty.
Figure 3. Images A–D illustrate incisions and surgical osteotomies for the mandibular advancement.
Figure 2
Figure 3