Surgical Options for Obstructive Sleep Apnea

Michael W. Marshall, DDS

The pathology associated with obstructive sleep apnea is cumulative and progressive. When patients fail to improve with continuous nasal airway pressure or other, less-invasive treatments, surgery should be considered. The initial approach to the surgical patient is identification of all areas of potential obstruction. There are often several sites of obstruction, which can occur anywhere in the upper respiratory tract. One or more procedures may be needed to address these areas. The objective of surgery is to relieve these obstructing sites without interfering with the normal functionality of the upper airway.

Article copyright 1998 Journal of the California Dental Association.
Photographs copyright of the authors.

Obstructive sleep apnea is sleep-disordered breathing resulting from an anatomical obstruction of the upper airway. Obstructive sleep apnea should be thought of as a diffuse airway disease that has several potential sites of occlusion. Surgical correction is based on either bypassing those sites, removing the obstructing tissue, or repositioning the tissue and decreasing tissue laxity. In most patients with obstructive sleep apnea, surgery is not a primary treatment option. However, surgery is initially considered in patients with an obvious mass, tumor, or skeletal abnormality that is causing obstruction. Weight loss, nasal continuous positive airway pressure, dental airway appliances, behavioral modification, and pharmacotherapy still remain the initial treatment for patients with this problem.

Surgical correction is indicated in those patients who cannot tolerate other non-invasive treatments or for whom those treatments have been unsuccessful. One of the most effective and widely used forms of nonsurgical treatment is nasal continuous positive airway pressure. Rarely does continuous positive airway pressure fail to help patients with obstructive sleep apnea. Such failure is usually related to lack of compliance. Studies have shown that 40 percent to 50 percent of patients are unable to tolerate the device for long-term use.¹ Continued and efficacious treatment is critical in the patient with sleep-disordered breathing. There is a significant mortality and morbidity associated with obstructive sleep apnea, even for those younger than 50. It is now clear that patients with obstructive sleep apnea have an increased potential for development of cardiovascular complications such as hypertension, cardiac arrhythmias, stroke, and myocardial infarction.² The central nervous system is also affected by the disruption and the lack of deeper planes of sleep critical to proper brain function. When obstruction occurs, the patient awakens or moves to lighter planes of sleep, which disrupts the brain's ability to maintain normal sleep patterns.³ This resultant sleep fragmentation causes excessive daytime sleepiness (hypersomnolence), which is a major complication of obstructive sleep apnea. Hypersomnolence can impair alertness, cause work and driving accidents, and affect work and social functioning. The pathology associated with obstructive sleep apnea illustrates the necessity for surgical intervention following failure of less-invasive measures.

Evaluation for surgical correction consists of careful examination of the nose, soft palate, tonsils, adenoids, tongue, mandible, and larynx. Nasopharyngoscopy may be helpful in evaluating many of these areas and determining the location of airway closure.⁴ Cephalometric radiographs are also routinely used and have been shown to be closely correlated with volumetric computerized tomography studies in determining sites of soft tissue obstruction.^5,6 Cephalometric radiographs are also necessary to identify mandibular deficiencies, genial deficiencies, and retropositioned hyoid bones, all of which can contribute to airway closure during sleep.^7-11 These exams are done by both the otolaryngologist and oral and maxillofacial surgeon to use the expertise of both specialties since the problem is not confined to a specific site in the upper airway. Even with extensive clinical and radiographic evaluation, it is often difficult to accurately identify all areas of obstruction. This is a result of the inability to evaluate the patient while he or she is asleep. There are physiologic changes resulting in upper airway closure or narrowing that occur only during sleep.

Once a determination of the site or sites of obstruction has been made, the medical status of the patient must be thoroughly considered. Because of the significant morbidity associated with obstructive sleep apnea, patients may be at high risk for anesthetic or postoperative complications, which would influence the choice of surgical options.

In the past, the only surgical option for treatment of symptomatic obstructive sleep apnea was a tracheotomy. This procedure has a high rate of treatment success, but the associated complications and social stigma fueled the need to develop other, less-morbid surgical options. It was not until 1981 that Fujita utilized the uvulopalatopharyngoplasty for treatment of obstructive sleep apnea in adults.¹² Though this treatment was very beneficial for snoring, the success rate for resolving obstructive sleep apnea using this procedure alone was poor. Powell and colleagues in 1983 described the utilization of mandibular and maxillary procedures that addressed other contributing areas of obstruction.¹³ Combining these procedures in the appropriate patient has lead to increasing success rates. Obstruction can occur at any point from the nose to the larynx and often does at several locations. Surgical intervention now consists of procedures that relieve obstruction in the nasal cavity, nasopharynx, oropharynx, and hypopharynx. Not only do these procedures relieve the obstruction and enlarge the upper airway, they can also help stabilize upper airway soft tissue. Magnetic resonance imaging results have shown a sleep-induced relaxation of upper airway dilator muscles that decreases the anterior-posterior diameter of the upper airway to a critical obstructive size in patients with obstructive sleep apnea.¹⁴ This explains the need for not only enlarging the airway but also reducing tissue laxity. Once the potential sites of obstruction have been determined, the decision as to which surgical procedures to perform must be made keeping in mind the necessity for both airway enlargement and stabilization.

Surgical Options

Nasal Surgery

Nasal obstruction occurs as a result of bony or cartilaginous abnormalities or from reactive soft-tissue changes that decrease airflow and increase airway resistance. The primary goal of nasal surgery in sleep-related breathing disorders is to reduce nasal resistance. This is necessary to reduce negative intrapharyngeal pressure during inspiration. The negative pressure causes the loose pharyngeal walls to collapse, which results in obstruction of air flow.¹⁵ Treatment usually includes septoplasty, turbinectomy, polypectomy, or a combination of these procedures. Series and colleagues have studied the effect of nasal surgery in patients with moderate obstructive sleep apnea.¹⁶ They found a substantial improvement in apneas and sleep-stage changes after surgery in patients with normal cephalometry, but the improvement did not result in resolution of the obstructive sleep apnea. Nasal surgery alone is rarely curative for obstructive sleep apnea patients because nasal obstruction alone does not usually cause sleep apnea. Nasal surgery may also help in improving the tolerance of continuous positive airway pressure.

Tonsillectomy and Adenoidectomy

Tonsils and adenoids contribute to obstruction at the oropharyngeal and velopharyngeal levels, respectively. Tonsillectomy and adenoidectomy alone are usually done only in children with severe snoring with or without a diagnosis of obstructive sleep apnea. Suen and colleagues reported an 85 percent normalization of the respiratory disturbance index after adenotonsillectomy in children with obstructive sleep apnea.^17,18 Thus, this procedure alone may be effective in treating children with obstructive sleep apnea. Respiratory disturbance index or other sleep study parameters alone should not be used to determine resolution or improvement in obstructive sleep apnea, however. Subjective and objective clinical improvement is also needed when assessing the benefits of treatment.

In adults, there is a natural recession of adenotonsillar lymphoid tissue, and as such it is usually not a major contributing factor in obstruction leading to sleep apnea. It is very common for residual tonsil tissue to be removed at the time of uvulopalatopharyngoplasty to help decrease airway resistance and increase pharyngeal volume.

Uvulopalatopharyngoplasty

Uvulopalatopharyngoplasty was the first surgical procedure specifically utilized to address the palatal abnormalities seen in many patients with obstructive sleep apnea. Uvulopalatopharyngoplasty was originally developed for the treatment of snoring, and because it was noted that snoring is a major component of obstructive sleep apnea, it was thought that alteration of the palate may also influence obstructive sleep apnea. The procedure itself consists of removal of a portion of the glossopalatal arch and soft palate, including the uvula and tonsils, if present (Figure 1).

Figure 1. Uvulopalatopharyngoplasty with removal of soft palate, uvula and lateral pharyngeal tissue.

This is done in hopes of correcting retropalatal collapse and/or narrowing. This procedure has a low morbidity rate but is not without significant complications. Nasal regurgitation, nasal reflux, velopharyngeal stenosis, velopharyngeal incompetence, pharyngeal dryness, speech abnormalities, dysphagia, loss of taste, hemorrhage and postoperative breathing difficulty have all been described.¹⁹ Though Uvulopalatopharyngoplasty is very effective for curing snoring, multiple studies have shown an average of only 50 percent success rate with respect to overall improvement of obstructive sleep apnea.^20,21 The poor success rate appears to be mainly a result of not addressing other concomitant areas of obstruction when considering surgical correction. It is now known, based on more thorough clinical exams and more specific studies such as fast computerized tomography cine, that in many patients not only is the velopharynx a major site of obstruction but so is the hypopharynx. Another reason for the consistent lack of improvement is the variability in which the procedure is performed. Due to the significant potential for development of velopharyngeal incompetence and its associated problems, a conservative removal of soft tissue is often done. It is not uncommon to need further resection if symptoms continue and evidence of velopharyngeal obstruction is still present.

Laser-Assisted Uvulopalatopharyngoplasty

Laser-assisted uvulopalatopharyngoplasty has been utilized as a treatment for both snoring and obstructive sleep apnea.²² The procedure is performed by placing vertical laser incisions lateral to the uvula bilaterally. This produces vertical and fibrotic "trenches" beside the root of the uvula. Further debulking of the bottom and lateral sides of the uvula is then done thereby creating a higher and smaller uvula. This is done during the course of two to five outpatient procedures in which 5 to 8 mm of velum is removed each time to theoretically elevate the new velum to Passavant's ridge.²³ The benefits of this procedure are less morbidity and no need for hospitalization. Laser-assisted uvulopalatopharyngoplasty has been very beneficial for the treatment of snoring, but its efficacy in the correction of obstructive sleep apnea is still controversial. A recent study has shown it to be as effective as uvulopalatopharyngoplasty, though the rate of cure of obstructive sleep apnea was still only 44.7 percent.²⁴ The authors do not recommend laser-assisted uvulopalatopharyngoplasty in patients with oxygen desaturations of less than 85 percent or a respiratory disturbance index of greater than 20 unless continuous positive airway pressure is also used during the treatment process. For those patients with mild obstructive sleep apnea and/or obstruction only at the velopharynx, this may be a good alternative to uvulopalatopharyngoplasty.

Tongue Surgery

Surgical resection of portions of the tongue has been developed to help enlarge the hypopharyngeal airway space. Though this enlargement can also be accomplished with genial advancement, hyoid suspension, and maxillomandibular advancement, patients with an abnormally large tongue or tongue base may benefit from these reduction procedures. Resection can involve portions of the lateral and/or dorsum of the tongue. For those patients with persistent and severe sleep apnea with evidence of narrowing of the hypopharynx by the tongue base, a midline glossectomy with posterior tongue reduction has also been tried. These procedures have met with variable results and are not without significant complications. Bleeding, dysphagia, and moderate pain on swallowing are common and may persist for two to three weeks. The midline glossectomy has also been combined with an epiglottidectomy in those cases where the epiglottis is contributing to the obstruction.²⁵ Patients treated with this combined procedure run the added risk of chronic aspiration of matter into the trachea. It appears that tongue reduction, particularly posterior resection, should be utilized only after all other modalities of anterior tongue repositioning have failed.

Genial Advancement and Hyoid Suspension

Figure 2a. Prior to genial advancement. Figure 2b. After genial advancement, the lingual cortex and attached genioglossus and geniohyoid muscles repositioned anteriorly and fixated with titanium screw. Buccal cortex has been removed on the advancing segment. Note the lack of significant soft tissue alteration of the chin. Figure 2c. Panorex after genial advancement.

Obstruction at the hypopharyngeal region can be a result of posterior positioning of the tongue; excessive tongue laxity, in which the tongue falls back during sleep and occludes the airway; or abnormal size as described above. If the tongue size is within normal limits and there is evidence of hypopharyngeal obstruction, treatment is directed at opening the posterior airway space and stabilizing the ligamentous and muscular attachments of the tongue. This is done by advancing the attachments of the tongue at the genial tubercles and the hyoid bone.^3,26 The genial advancement procedure consists of a rectangular bicortical osteotomy, which is performed below the apices of the mandibular anterior teeth and does not include the inferior border of the mandible. This creates a free bony segment that includes the genial tubercles and the attached genioglossus and geniohyoid muscles. This is then advanced the full width of the mandible so that the lingual cortex is anterior to the buccal cortex. The rectangular bony segment with muscles attached is then rotated 90 degrees to maintain this anterior position. The buccal cortex of the advanced segment is then removed and the lingual cortex stabilized using a titanium screw (Figures 2a through c). This can result in from 10 to 15 mm of advancement, depending on the thickness of the mandible. This reduces the potential for posterior tongue displacement. The osteotomy can be varied and include the inferior border if lower facial augmentation is needed for esthetics. Genial advancement is often done in conjunction with the hyoid suspension but may also be done alone. On cephalometric exam, if the posterior airway space is within normal limits but there is evidence of hypopharyngeal narrowing due to tongue displacement, the genial advancement alone may correct the obstruction. The most significant complication with this procedure is the potential for mandibular fracture, though leaving the inferior border intact has significantly reduced this problem. Patients will often have a transient paresthesia of the lower incisors. Speech and swallowing are not affected.

Figure 3. Pre and post-operative position of hyoid bone after suspension from mandibular symphysis.

The hyoid suspension more directly addresses the posterior positioning of the tongue and also helps in reducing tongue laxity. The procedure consists of releasing the infrahyoid muscles (omohyoid, sternohyoid, thyrohyoid), then advancing the hyoid both anteriorly and superiorly by suspending it from the inferior border of the mandible.^13,26,28 This stabilizes the base of the tongue in a more anterior position and enlarges the pharyngeal space (Figure 3). A more recent modification of this procedure is to suture the hyoid, after infrahyoid release, to the thyroid cartilage.²⁹ Complications include dysphagia, which is usually transient; injury to the superior laryngeal nerve; and possible aspiration if the thyrohyoid membrane is violated. Even when the genial advancement is combined with the hyoid suspension, speech and swallowing are usually not affected after the initial edema has resolved.

Maxillofacial Surgery

Figure 4a. Narrowed posterior airway space and hypopharyngeal obstruction due to mandibular retrognathia and associated posterior tongue position. Figure 4b. Enlargement of posterior airway space with mandibular and genial advancements

Maxillary and mandibular advancement procedures are commonly done for correction of dentofacial deformities, but these procedures are also therapeutic for the treatment of obstructive sleep apnea. In the patient with a dentofacial deformity and subsequent sleep-disordered breathing, it is clear that correction of the anatomic abnormality should be addressed initially. In the normocephalic patient, maxillomandibular advancement procedures are usually considered only after failure of other surgical procedures that attempt to more directly alter the specific area of obstruction as described above. In these refractory patients, maxillomandibular advancement procedures have been shown to have a high rate of success.^30,31,34 Advancement of the facial skeleton has the benefit of expanding the pharyngeal airway space both anteriorly and laterally since all muscle attachments of the tongue and soft palate are maintained. This provides a significant volumetric increase in pharyngeal space without disturbing the functions of speech or swallowing (Figures 4a and b). The most difficult part of treating this type of patient is preserving a functional occlusion and maintaining acceptable esthetics. If time permits, orthodontic treatment of the Class I patient would include mandibular premolar extraction with retraction of lower anteriors.

Figure 5a. Preoperative photo.	Figure 5b. Preoperative cephalometric X-ray
Figure 5c. Postoperative photo.	Figure 5d. Postoperative cephalometric X-ray after 6 mm maxillary and mandibular advancement in a patient with a pre-existing Class I occlusion. Note the increase in posterior airway space and acceptable esthetics.

If orthodontics is not an option, surgical dentoalveolar retraction can be done as a separate pretreatment procedure. In many patients, however, maxillomandibular advancement of 5 to 8 mm can be accomplished without significant esthetic alteration (Figures 5a through d). Commonly used osteotomy procedures, such as the high Le Fort osteotomy, bilateral sagittal-split osteotomy, and the use of rigid internal fixation have significantly improved the ability to advance the mandible and maxilla with predictable stability.^30,31

Tracheotomy

Most practitioners agree that a tracheotomy results in 100 percent cure for patients with obstructive sleep apnea (Figure 6).

Figure 6. Tracheotomy placed solely for the treatment of obstructive sleep apnea.

It has been shown that a tracheotomy results in normalization of apneic indices and resolution of cardiac arrhythmias.³² It is understandable that if the entire upper airway is bypassed, there is no potential for obstruction. For most patients, however, a tracheotomy is not an acceptable treatment. In patients with severe obstructive sleep apnea and resultant cardiac compromise, a tracheotomy may be the only surgical option. Clinical urgency would dictate the necessity for a tracheotomy rather than other, less-morbid treatment alternatives. Not only can a tracheotomy result in physical complications such as recurrent bronchitis, bleeding, and stenosis, but there are also significant psychosocial problems.³² Depression, spousal rejection, and problems with work may occur, thus this procedure is reserved for only the most refractory cases. Depending on the severity of the case, a tracheotomy may also be performed as a temporary procedure until it is clear that the airway is unobstructed from swelling as a result of other upper airway procedures.

Discussion

The determination as to which surgical procedure(s) to perform in the obstructive sleep apnea patient is more complex than merely a consideration of polysomnographic (sleep study) results. These results must be weighed along with the current symptomatology of the patient, nasopharyngoscopy results, a clinical exam, a cephalometric evaluation, and the current health status of the patient to determine the most appropriate and potentially successful surgery. Certainly, if anatomic abnormalities exist, such as retrognathia, micrognathia, or microgenia, then the focus of treatment should be directed in these areas. But several obstruction sites can contribute to obstructive sleep apnea, and in the majority of patients, both the soft palate and tongue are obstructing. This helps explain the initial poor overall improvement with uvulopalatopharyngoplasty alone. At one time, it was the only recommended procedure for the treatment of obstructive sleep apnea, but it did not address possible hypopharyngeal obstruction. Treatment failures who went on to have genial advancements and hyoid suspensions showed significant improvements. Now that more information is becoming available as to the contributing areas of pathology, more careful evaluation of the upper airway is done thus improving treatment success by addressing all areas of obstruction. Unfortunately, surgical treatment is still in its infancy in regard to these patients. Even with careful evaluation and improved techniques for site-specific treatment of possible areas of obstruction, surgical results are still not highly predictable. It is with this in mind that patients are informed of the potential need for multiple, staged procedures. Practitioners must always weigh the potential morbidity and mortality of the procedures with the potential for improvement.

In the patient with simple snoring or mild to moderate obstructive sleep apnea without evidence of hypopharyngeal obstruction, the surgical options are more clear. Laser-assisted uvulopalatopharyngoplasty or uvulopalatopharyngoplasty are the treatments of choice. The laser-assisted uvulopalatopharyngoplasty is a less morbid procedure and can be done in an outpatient setting, but its efficacy in treating obstructive sleep apnea is still under study. The amount of pharyngeal tissue removed is much more limited than in the uvulopalatopharyngoplasty, and as such may not entirely address pharyngeal narrowing leading to obstruction. If the patient is significantly symptomatic, then consideration should be given for the more aggressive uvulopalatopharyngoplasty.

If the posterior airway space is not abnormal but tongue laxity or size indicates a potential for obstruction, then genial advancement can be utilized. With the genial attachments brought from lingual to buccal, the muscle and ligaments are tensed the thickness of the symphysis and thus will decrease the distance the tongue can fall posteriorly during sleep. If there is no significant improvement and there is evidence of hypopharyngeal obstruction continues, the hyoid suspension can be done.

If hypopharyngeal obstruction exists, then genial advancement and hyoid suspension would be the treatments of choice. When significant posterior airway space narrowing is present, then both genial advancement and hyoid suspension give the best potential for success since these two procedures anteriorly reposition the attachments of the tongue, thus moving the base of the tongue forward, and decrease tongue laxity. Using both these procedures, the hyoid can be advanced as much as 20 to 30 mm as measured on the cephalometric X-ray. Unfortunately, the amount of anterior tongue advancement is not proportional to the amount of bony advancement. Relapse does occur but typically not back to baseline. If problems still persist, then maxillofacial surgery is considered.

When a skeletofacial abnormality is present in the patient with obstructive sleep apnea, treatment should initially be directed at correcting the abnormal anatomy. This may be a developmental abnormality, such as the patient with Pierre-Robin syndrome and resultant retrognathia, or may be a result of systemic disease, such as rheumatoid arthritis with associated condylar resorption causing posterior mandibular repositioning and tongue displacement (Figures 7a through d).

Figure 7a. Preoperative photo. Figure 7c. Postoperative photo. Patient underwent maxillary advancement and impaction, mandibular advancement and genial advancement.	Figure 7b. Preoperative cephalometric X-ray of patient with rheumatoid arthritis and associated TMJ involvement resulting in mandibular displacement and hypopharyngeal obstruction.
	Figure 7d. Postoperative cephalometric X-ray.

The use of mandibular and/or maxillary advancement procedures in these patients is a primary treatment option. Currently, the Class I occlusion patient with significant, symptomatic obstructive sleep apnea that has failed other surgical procedures is now considered for these same procedures. It has been the experience of the author and others that patients, refractory to other forms of surgical intervention, have highly successful and predictable improvements utilizing maxillofacial advancement procedures.^{13,30,31,33,34} These procedures have also been considered as primary surgical treatments. Waite and colleagues reported on a series of patients in which maxillomandibular advancement surgery was the primary surgical option.³⁴ Ninety-six percent of patients were subjectively and objectively improved with desaturations of less than 90 percent greatly decreased. Sixty-five percent of patients achieved a reduction in the respiratory disturbance index to a level of less than 10. These results were based on repeat polysomnograms obtained at one week and six weeks. It is typically recommended that follow-up polysomnograms be obtained at six months after surgery to assure full resolution of swelling and stabilization of healed tissues. It should be stressed, however, that the polysomnogram is not the only determinant of surgical success. Patients may have an improvement in their polysomnographic parameters to near normal levels but still continue to experience daytime sleepiness or other problems related to obstructive sleep apnea. If the patient is still symptomatic and there is evidence of continued hypopharyngeal obstruction, then tongue reduction surgery may be an option.

When all else has failed or the patient's risks from surgery are too great, a tracheotomy should be considered. This is the one procedure with a 100 percent cure rate for obstructive sleep apnea. This procedure should be reserved for only the most extreme cases because of its significant associated morbidity.

Surgical candidates present with both diagnostic and surgical challenges. To effectively treat these patients, more than one procedure may be needed simultaneously. The amount of tissue reduction or anatomic advancement has to be balanced with maintaining the other functions of the pharynx, such as speech and swallowing. The severity of the existing disease and the patient's current health status may exclude staging of surgeries. These factors, along with the variable success rates associated with the current surgical procedures, make the permanent correction of obstructive sleep apnea a continued effort.

Author

Michael W. Marshall, DDS, is affiliated with the Sleep Disorders Center at Long Beach Memorial Medical Center and is a board-certified oral and maxillofacial surgeon with offices in Huntington Beach and Bellflower.

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To request a printed copy of this article, please contact/Michael W. Marshall, DDS, 14343 Bellflower Blvd., Bellflower, CA 90706.