Controversies in Surgical Management of Sleep Apnea

One of the more controversial issues in otolaryngology deals with the sleep-obstructive patient. This spectrum ranges from patients with the noise-only snore, to patients who frequently awaken with sleep interruption disorder of snoring, to patients with full-blown apnea with documented obstruction and desaturation. Several standards are established for the criteria for apnea, on the basis of frequency of pauses and degree of oxygen desaturation stated as the clinical parameters of sleepiness. It remains puzzling that when one compares symptoms of sleepiness with research data, patients who are frequently awakened by their own snoring, or who awaken from nocturnal restless periods, are often more fatigued and symptomatic than are patients with mild to moderate apnea. I find the best parameters to follow are persistent fatigue after sleep and daytime fatigue with sleepiness.

This chapter compares clinical assessment and patient counseling regarding continuous positive airway pressure (CPAP) with the results achieved with palatal surgery or dental appliances. Office-based palatal reduction and tongue base reduction remain either unproven for true sleep apnea patients or somewhat experimental.1

The initial controversy faced by many of us is the value of CPAP and its effectiveness in the long-term management of sleep apnea. The trend of managed care has been to require patients to use CPAP as first-line therapy before considering surgery. CPAP has proved the most effective and safest form of therapy, but compliance and patient acceptance are usually dismal, with the patient often remaining untreated with the machine at the bedside.1'2

Patients I do not consider candidates for CPAP, and who I do not feel obliged to have fail this modality before surgery, are those with nasal obstruction3 or significant tonsil hypertrophy. These patients have obstruction that can be dealt with by time-proven surgical techniques, with a high potential for cure. In the overweight patient with no significant nasal obstruction, CPAP is by far the most effective and possibly only effective treatment other than tracheostomy. Unfortunately, even this population is reticent to accept the lifelong commitment to CPAP. In addition, nasal tip instability or tip collapse may often be worsened by CPAP, making this modality a non-option requiring tip-lift rhinoplasty or tip reconstruction as well.

The effectiveness of surgery as successful treatment of apnea has been established.4 The larger issue is identifying the limiting factors of patient characteristics that lead to unsuc cessful surgery. Clearly, weight is the most limiting factor for success. As people become extremely obese, the posterior oronasal aperture narrows. This decrease in cross-sectional area limits the maximum dimension that can be obtained by surgery. Therefore, I tend to recommend against surgery for uvulopalatopharyngoplasty (UPPP) unless large tonsils are involved. Removal of these with UPPP may still effect a cure or may allow a reduced pressure CPAP utilization, increasing compliance.

Tonsillar hypertrophy is a positive factor in determining surgical outcome. If a patient has large obstructive tonsils, this alone or in conjunction with UPPP often creates a surgical cure. I consider significant tonsillar hypertrophy a contraindication for CPAP, because surgical intervention can create a cure and will not require patient compliance for the use of CPAP in the future. Conversely, in a patient with a long palate or a large uvula with normal tonsils (not beyond the anterior pillar), or both, I do not recommend tonsillectomy. Postoperative constriction of the tonsillar fossa with loss of lateral dimension often replaces a lost volume of tonsillar tissue. In addition, the superior-to-inferior contraction of the fossa with the loss of a tonsillar lingual sulcus pulls the tongue base superiorly, limiting the oropharyngeal opening somewhat as well. The risk of postoperative hemorrhage and airway swelling is not justified unless the tonsils are enlarged and the overall net gain of space, considering the postoperative fossa contractions, results in an overall opening of the airway.

Nasal obstruction is a positive factor in sleep apnea when considering recommendations for surgery. The more obstructed the nose, considering both the septum and turbinate involvement, the more likely a positive outcome will be obtained with surgery. Certainly evaluation of the nasopharynx for adenoid hypertrophy or other obstructive masses is mandatory. The turbinates are usually surgically reduced in size in the sleep apnea patient. The increased obstructive effect in the nighttime airway due to the venous enlargement of the turbinates in the recumbent patient often makes the nighttime airway worse than the patient's daytime baseline. Significant nasal tip droop in the elderly patient or nasal tip instability is a positive factor for recommending surgery as well. CPAP including the use of CPAP pillows often does not prove beneficial in patients with tip collapse.

Age is a relative limiting factor. Certainly the tissue laxity of aging causes palatal collapse. Tongue base and cervical tissue collapse seem worse as well. However, correction of these obstructions in the nonobese patient may yield a rewarding result. When not severe, retrognathia may also be a relative limiting factor. Cephalometrics (normal anteroposterior dimensions of the tongue base to posterior wall) may be helpful predictors. I have found sleep fluoroscopy helpful as a predictor of epiglottic or tongue base collapse, but it is prohibitively cumbersome to set up and accomplish from a practical standpoint. Surgery may be beneficial in the nonobese patient with moderate retrognathia with nasal obstruction and large tonsils. I do not believe that mild retrognathia limits surgical recommendations. In order to use a mandibular advancement splint adequately, the nasal and pha-ryngeal airway needs to be opened.

The risk of palatal insufficiency after UPPP with resultant hypernasal speech or regurgitation of liquids or foods into the nasopharynx is often used to argue against the surgery. I have found this to be completely without merit. An accurate choice of the level of dissection below the point of muscular closure will avoid this problem in all surgical cases.

The technique is simple and effective. At surgery, before induction of the anesthetic, the patient is asked to sit upright on the surgical table. The palate is visualized, and the patient is asked to say "ah" and "K." The concavity of the palate where it closes against the nasopharyngeal wall is visualized. This is termed "the palatal buckle." A point at 0.75 cm below the palatal buckle is chosen and marked with a spinal needle and with Methylene Blue. This is considered the highest point of resection for the palate. This is based not on arbitrary measurements from the posterior wall or from the bony palate but anatomically, on the point of palate closure. This approach not only limits the amount of palate taken to avoid overresection, but also ensures maximal removal of collapsible tissue for optimal results. It is based on the individual patient's muscular closure, and not on an arbitrary measurement. I have observed no palatal insufficiency in any patient undergoing this technique.

In summary, the highest success with surgery will be achieved in the younger nonobese patient with large tonsils, a long palate and large uvula, and normal mandibular anatomy. Obese patients generally do poorly unless there is a relatively overwhelming factor, such as tonsil hypertrophy or nasal obstruction. Surgery may still be useful in these patients, as a means of lessening their symptoms, the number and length of apnea pauses, and the overall reduction of time spent under a 90% saturation of oxygen. The surgical approach may be an adjunct in the successful management of the CPAP at lower pressures while weight loss measures are attempted.

REFERENCES

Kereiakes—CHAPTER lO

1. Barthel SW, Stome M. Snoring, obstructive sleep apnea, and surgery. Med Clin North Am 1999;83:85-96

2. McArdle N, Devereux G, Heidarnejad H, et al. Long-term use of CPAP therapy for sleep apnea/hypopnea syndrome. Am J Respir Crit Care Med 1999;159(pt 1):1108-1114

3. Hester TO, Phillips B, Aracher SM. Surgery for obstructive sleep apnea: effects on sleep, breathing, and oxygenation. South Med J 1995;88:907-910

4. Lojander J, Maasilta P, Partinen M. Nasal-CPAP, surgery, and conservative management for treatment of obstructive sleep apnea syndrome. A randomized study. Chest 1996;110:114-119

Uvulopalatopharyngoplasty (UPPP), first introduced in 1981 by Fujita1 for the treatment of obstructive sleep apnea (OSA), is now the most frequently performed surgical procedure for this disorder. Despite its widespread use, it is effective in less than 50% of patients with OSA. According to the American Sleep Disorders Association meta-analysis, only 40.7% of patients with OSA respond to UPPP; response was defined as a 50% decrease in apnea index (AI) or respiratory disturbance index (RDI) and the resultant achievement of an RDI of <20 or an AI of < 102 This definition is loosely based on limited mortality data; patients with an AI of > 20 have much higher mortality.3

To improve success rates, a number of methods have been proposed to select patients who will respond favorably to UPPP: somnofluoroscopy, pharyngeal computed tomography (CT) scan, awake fiberoptic endoscopy with and without Muller's maneuver, asleep endoscopy with continuous positive airway pressure (CPAP), airway manometry, and cephalome-try.2 Two of these methods—fiberoptic endoscopy with Muller's maneuver (FEMM) and lateral cephalometry—are relatively inexpensive and readily accessible to the clinician. Initial studies concluded that they were useful for predicting UPPP

success.

Early cephalometric studies suggested that those who fail to benefit from UPPP have narrow retrolingual airways. Riley et al4 and Gislason et al.5 found that nonresponders have a narrow posterior airway space (distance between the base of the tongue and posterior pharyngeal wall), an inferiorly positioned hyoid, and macroglossia. In contrast, Ryan et al.7 demonstrated that patients with a narrow posterior airway space are actually more likely to respond to UPPP. More recent studies have not shown a significant difference between responders and nonresponders.8-10 Therefore, the value of traditional cephalometric analysis in predicting response to UPPP is low. Despite its low predictive efficacy, cephalometry continues to be studied intensively. In a recent study, cephalometric analysis was useful for selecting UPPP responders when OSA patients were stratified by skeletal type.11 Such studies hold promise that cephalometry may reliably be used to predict response to UPPP in the future.

Awake FEMM has also been proposed to help identify good UPPP candidates. Sher et al.6 introduced fiberoptic endoscopy for the preoperative evaluation of patients with OSA. Sher found the predictive value of FEMM to be high; 87% of patients with collapse confined to the velopharynx during FEMM had greater than 50% reduction in AI. In contrast, Katsantonis et al.12 and Aboussouan et al.13 were unable to predict success for patients with velopharyngeal collapse. However, these investigators found that FEMM has a high negative predictive value; in other words, they were able to predict failure for those with hypopha-ryngeal collapse. They concluded that FEMM may be useful in identifying poor UPPP candidates, that is, patients with hypopharyngeal collapse. Still other workers have concluded that FEMM has no predictive value.10'14

Lateral cephalometry and FEMM have not been universally accepted or validated for selecting OSA patients who will respond to UPPP. Although objective, easily accessible, and relatively inexpensive, the predictive value of both techniques is low, as they may not localize the critical obstructive pathophysiology that occurs in OSA patients during sleep. It is also possible that these methods may identify the site of obstruction, but that UPPP surgery does not reliably alleviate the abnormality that causes OSA. Several studies have demonstrated that in most UPPP failures the level of obstruction is retropalatal.15-17 Persistent obstruction at the level of the palate may account for the low predictive efficacy of techniques such as fiberoptic endoscopy and lateral cephalemetry.

A thorough history and physical examination are extremely important in evaluating patients for OSA. Patients with OSA frequently complain of snoring, restless and fragmented sleep, excessive daytime sleepiness, morning headaches and confusion, and poor work performance. The typical patient is overweight with a short, fat neck. Examination of the oral cavity, nose, and pharynx is critical. Patients often have an elongated soft palate and uvula associated with laxity of the posterior and lateral pharyngeal walls and tonsillar pillars. The tonsils may be enlarged, although tonsils of normal size may contribute to airway obstruction as a result of oropharyngeal size or ptosis. In addition, mandibular size, height and shape of the hard palate, and tongue size and position are assessed. Nasal examination is important to rule out nasal obstructive lesions such as septal deviation, nasal polyposis, turbinate hypertrophy, and adenoid hypertrophy. To examine the pharynx, flexible fiberoptic endoscopy is performed; thus, specific space-occupying lesions are identified. Approximately 3 in 200 adult patients with OSA have such a lesion.2 Surgical removal will correct OSA. Finally, medical disorders such as hypothyroidism, amyloidosis, and other matabolic storage disorders that may contribute to upper airway obstruction must be ruled out if appropriate.

All patients suspected of having OSA on the basis of history and physical examination are evaluated with polysomnography (PSG). Patients diagnosed with OSA by PSG are first treated medically. They are counseled to avoid alcohol and sedative medication, to lose weight, and to alter sleep position if the apnea is position related. However, behavior modifications alone are rarely successful. Mechanical devices that affect oral and pharyngeal mechanics benefit some patients. Most with

OSA require nasal CPAP, the mainstay of medical therapy. It is highly effective for treating OSA when properly and consistently used.18 In addition, CPAP, unlike UPPP, has been shown to reduce mortality.3 CPAP, however, is often poorly tolerated, making long-term compliance a problem.

Patients who fail to tolerate nasal CPAP are surgical candidates. A select few are treated with procedures other than UPPP. Patients with significant sequelae of OSA, including cardiac arrhythmias, cor pulmonale, and disabling somnolence, are encouraged to have a tracheostomy. Tracheostomy, like nasal CPAP, is highly effective at resolving OSA and its complications and has been shown to reduce mortality.2 In a select group with mild OSA, nasal obstruction, and normal oral and pharyngeal anatomy, nasal surgery alone may be successful.19 Finally, patients with specific craniofacial abnormalities are evaluated by our craniofacial team and treated appropriately.

All other individuals are first offered UPPP. Patients are not selected on the basis of lateral cephalometry, FEMM, or other techniques. Although patients with milder OSA are more likely to respond to UPPP,2 all patients with OSA, regardless of severity, are offered UPPP. Even though more patients with severe OSA may not respond as defined, many will, and, for those who do not, improvement in their OSA may allow them to decrease their CPAP pressures to tolerable levels. For patients with OSA and nasal obstruction, nasal surgery is performed at the time of UPPP, except in the cases noted previously.

After UPPP, PSG should be repeated. On the basis of these results, nasal CPAP may be adjusted or terminated. Patients with persistent OSA and who are unable to tolerate CPAP are evaluated for other maxillofacial procedures, including genio-tubercle advancement, hyoid fixation, and maxillomandibular advancement. Success rates of 65 to 97% with these procedures have been reported.20-22 However, the number of studies evaluating such procedures is limited, and the preoperative selection of patients is frequently confusing and complex.

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