Introduction

Snoring is a significant social problem. Approximately 20% of the adult population (this figure increases to 50% in elderly people in their 60’s) is chronically affected 1 and approximately 3 to 4% of men and 2% of women of middle age meet the minimum criteria of Obstructive Sleep Apnea (OSA), which is considered the most advanced stage of snoring.4,5

Snoring or OSA diagnosis, like some other sleep disorders, is achieved by polysomnography, exam that also provides data about the quality and the quantity of sleep changes.6,7

The collapse of the airways during sleeping time that results in sleep disorders (snoring and obstructive apnea) frequently occurs in several sites, from the nasopharynx to the hypopharynx and may require surgical treatment in the several levels responsible for the obstruction. The factors that account for higher prevalence of OSA are: male gender, obesity, age, cranial-facial anomalies and familial history of the disease. Men are 6 to 7 times more likely to develop OSA and the rates increase with age. Two thirds (2/3) of the patients with OSA are obese, in other words, 20% are above the ideal weight.8

Among the treatment approaches available, the CPAP (continuous positive airway pressure) still remains the most effective treatment; however; there are patients with mild apnea that are not considered symptomatic enough for ventilation with CPAP. Still, there is a group that could not continue the follow-up of the treatment with CPAP due to adaptation issues with the equipment. In the category of non-invasive procedures, intra-oral devices can also be used, but there will be acceptance problems in the long run, just like CPAP.9

In the cases in which the clinical treatment is not indicated or is rejected by the patient the indication is the surgical treatment. apud9

Several surgical procedures are available for the correction of each area involved, with the palatal procedures being less complicated and invasive than the retro lingual and than those procedures carried out in the cases of collapse of in the hypopharynx level6,10 The nasal cavity, that may be an obstructive site from the nasal valve to the choana, should also be carefully evaluated. The correction of the obstruction at this level should not be performed as an isolated procedure but jointly associated to other procedures, since according to Utley et al., 199710 and Sériès et al., 199112, those corrections hardly ever are successful in the OSA if used alone. In spite of this partial effect in the treatment of OSA, the nasal surgery has other effect, which is to increase the tolerance to CPAP.12

In 1964, the surgeon Ikematsu described the uvulopalatopharyngoplasty (UPFP) as the first surgical treatment for snoring. apud13 In 1981, in the US, Fujita introduced the procedure, with minor changes, for the treatment of OSA. After finding out that the UPFP reduced the snoring in OSA patients, Fujita recommended the procedure for the treatment of snoring. Therefore, the UPFP quickly became the procedure of choice for snoring. In the technique described by Fujita, the patient undergoes tonsillectomy that is followed by partial removal of the soft palate, uvula, and tonsil pillars. Eventually, the tonsil pillars are put closer with sutures. The procedure is performed under general anesthetic drugs and the purpose is to reduce snoring by increasing the space of the velopharyngeal sphincter and reducing the vibratory tissue.15

The success rates of UPFP found in the literature are variable, near 50%15,16,17,18 and may reach up to 87% in selected patients 19.

In spite of the several procedures available, the efficiency of the surgical procedure in OSA is still unsatisfactory and should improve with the enhancement of the preoperative evaluation techniques that properly identify the anatomical site of the airway obstruction. Innumerable methods have been applied with this purpose, including: physical examination (focus on anatomical elements of the nose and oropharynx, perfilometry and body weight), manometry, radiographic exams such as CT, fluoroscopy and cephalometry.20, 21,22,23

The ideal test would be the one that could identify the airway site(s) responsible for the air flow resistance, non-invasive, of low cost and easily reproduced.24, 25,26,27 The most used exams for that purpose are nasopharyngoscopy with Mueller maneuver and cephalometry.28, 29,30

Borowiecki and Sassin (1983)31 were the first to report that Mueller maneuver, with forced respiratory effort against the obstructed airway, generating negative pressure in patients with severe OSA during wake, resulted in pharyngeal narrowing that reproduced the obstruction found during pharyngoscopy with optical fiber, performed during sleep time.

Sher et al. (1985)19 carried out the preoperative evaluation in all patients using the Mueller maneuver in an attempt to exclude those patients with obstruction at the hypopharynx level or in the base of the tongue from the surgical treatment, which resulted in a significant improvement in the post operative symptoms, such as apnea rate. Since then, nasopharyngoscopy with optical fiber and Mueller maneuver (NFMM) has been considered a preoperative diagnostic method of the collapse of the site of the airways that is practical and easy to apply.

Nasopharyngoscopy with Mueller maneuver
This exam is performed after local anesthesia with the patient initially seated. Larynx, vocal folds and the other pharyngeal structures are examined. Then, the device is positioned at the level of the base of the tongue and after the level of the soft palate (Figures 1 and 2), with the Muller maneuver being performed at these points, asking the patient to inhale deeply with their mouth shut, while the examiner occludes the nostrils. The Mueller Maneuver has the purpose of stimulating the changes that occur in the airways during snoring and apnea.32

The objective of this exam is to check the occlusion level in the structures mentioned. The level of collapse of the soft palate and the base of the tongue is evaluated with this maneuver which is generally scored in a 5-point scale (0=0%, 1=25%, 2=50%, 3=75% e 4=100%, the numbers correspond to the percentage of obstruction of the airway found during the exam).33 The level considered obstructive ranges from 50% to 75% in the reviewed literature. 28 As to the position for the exam, Doghramji (1995)28 and Terris et al. (2000)27 did not find differences in the results between the seated and supine position. The last author even reported similar results between the exams carried out by interns and assistants, highlighting its interpretation easiness.

Literature Review

Sher et al. (1985)19 reported that patient selection for UPFP with NFMM increased the success rate to 73% (considering success a reduction of at least 50% of index of the apnea or hypoapnea). This study included patients with 75% collapse at the soft palate level and moderate or minimum collapse at the hypopharynx level (up to 50%). In contrast to these pieces of data, Katsantonis et al. (1989) 34 found a low predictive value of this technique, with success rate of 33% in selected patients, however, we should point out that the global success rate of the study was 25% and that the patients included in the study had moderate to severe OSA, but between the group that was evaluated through the method and ranked as likely not responsive to UPFP, 77% actually obtained unsatisfactory responses with the treatment, concluding that the Maneuver is useful even to exclude the candidates to UPFP, specially if used in association with other methods. Similar data were found by Aboussovan et al. (1995)29 whose study assessed 29 OSA patients that had undergone UVPP with NFMM. The patients were divided into two groups based on the results of NFMM (and positive patients were those with an airway collapse above 75%): group 1 had velopharynx collapse and collapse of the tongue-epiglottis-hypopharynx complex and group 2 had collapse only at the velopharynx level. Patients had undergone the surgical treatment and the improvement was considered in those patients that had 50% improvement in the apnea/hypoapnea rate. The overall success rate was 62%, but it was significantly higher in the group 2 patients (77.8% for group 2 and 36.4% for group 1). When the author used a more stringent criterion in the evaluation of success (90% of improvement of apnea/hypoapnea rate), he obtained a success rate 5 times higher in group 2, concluding that due to the high negative predictive value, NFMM is better used to exclude patients with obstruction at the tongue-epiglottis-hypopharynx complex level from the group that should undergo UPFP.

In the study by Boot et al. (1997)33 60 patients with obstructive sleep apnea were assessed by questionnaire, polysomnography, cephalometry and Mueller Maneuver. NFMM was performed in the supine position and it was useful to separate the patients that presented collapse at the velopharynx and base of the tongue levels.

Dunlevy and Karakla (1998)35 reported that UPFP is an excellent treatment for young, non-obese patients with mild to moderate apnea and that have obstruction located at the level of the nasal and oropharynx (without, however, describing the method used to locate these segments.). The authors did not recommend UPFP for patients with severe apnea, thus agreeing with Boot et al. (1997).33

In contrast with the studies described above, Doghramji (1995)28 selected 53 patients with obstructive sleep apnea (OSA) for UPFP with apnea/hypoapnea rate of at least 5 per hour during polysomnography. Other criteria of inclusion were significant collapse at the soft palate level (higher than 50% during NFMM) and variable levels of collapse at the base of the tongue. Cephalometry was also performed in patients to evaluate the same structures. Both exams were carried out when the patients were awake. The response was defined as the reduction of at least 50% of apnea/hypoapnea rate. According to this criterion, only 32% of patients that have undergone UPFP had the expected results, and both nasofibroscopy with Muller Maneuver and cephalometry were not able to forecast the postoperative outcomes. In conclusion, these two exams (NFMM and cephalometry) did not properly locate the critical obstruction site of the airways in patients with OAS or possibly the site location action is effective, but UPFP does not relieve the critical anomaly that causes sleep apnea. The explanation suggested for this fact is that apnea would be caused by a severe collapse of the pharynx due to a dysfunction of the dilating muscles and that the static structures of the airways would be only a contributing factor. On the other hand, the improvement obtained with UPFP is highlighted with reference to the structural quality of the sleep and sleepiness at daytime, measured with objective methods (multiple sleep latency tests). Similar results were obtained by Petri et al. (1994)17 that performed UPFP in 30 non-selected patients, and most of the patients (2/3) had symptoms of moderate to severe apnea and had previously undergone NFMM and cephalometry; success of UPFP was considered 50% reduction of the apnea/hypoapnea rate or apnea rate below 20. The study concluded that cephalometry presented a predictive value of success contrary to NFMM.






Final Remarks

Although the literature does not provide a consensus on the use of NFMM for the selection of patients for UPFP, most of the authors agree that the exam in question is useful to exclude patients with obstruction below the velopharynx and that probably would not benefit from uvulopalatopharyngoplasty, therefore having negative predictive value for the selection of such patients; other surgical options should be considered.

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1 Associated Professor, Department of Surgery and Coordinator of the Discipline of Otorhinolaryngology,
Medical School, Pontifícia Universidade Católica, São Paulo.
2 Otorhinolaryngologist, graduated from Pontifícia Universidade Católica, São Paulo.
Address correspondence to: Karin Dal’Vesco – Rua Cândido Xavier, 210 ap.54
Batel Curitiba PR – 80240-280 – Tel (55 41) 243.3498 / (55 41) 9121.9112
Article submitted on August 17, 2001. Article accepted on September 28, 2001