Epiglottis Collapse in Adult Obstructive Sleep Apnea: A Systematic Review

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1 The Laryngoscope VC 2015 The American Laryngological, Rhinological and Otological Society, Inc. Systematic Review Epiglottis Collapse in Adult Obstructive Sleep Apnea: A Systematic Review Carlos Torre, MD; Macario Camacho, MD; Stanley Yung-Chuan Liu, MD, DDS; Leh-Kiong Huon, MD; Robson Capasso, MD Objectives/Hypothesis: To systematically review the international literature evaluating the role of the epiglottis in snoring and obstructive sleep apnea and to explore possible treatment options available. Data Sources: PubMed, Scopus, Embase, Google Scholar, Book Citation Index-Science, CINAHL, Conference Proceedings Citation Index-Science, The Cochrane Collaboration Databases, and Web of Science. Review Method: The searches were performed from the first year of each database through March 5, Results: Fourteen studies about the prevalence of epiglottis collapse in obstructive sleep apnea (OSA) were found. Most involved drug-induced sleep endoscopy studies that indirectly reported their findings about epiglottis collapse. The data suggests that the prevalence of epiglottis collapse in OSA is higher than previously described. The epiglottis has been implicated in 12% of cases of snoring, and sound originating from it has a higher pitch than palatal snoring. Continuous positive pressure (CPAP) surgery and positional therapy in the treatment of epiglottis collapse were also considered. Lateral position of the head may reduce the frequency of epiglottis collapse. With regard to CPAP, available reports suggest that it may accentuate collapse of the epiglottis. Surgery may help reduce snoring in some patients with a lax epiglottis and improve OSA in patients undergoing multilevel surgery. Conclusion: Knowledge regarding the role of the epiglottis in adult OSA and snoring patients is limited. The prevalence of this phenomenon in OSA seems to be greater than previously reported, and more research is needed to understand its role in OSA and the best way to treat it. Key Words: Obstructive sleep apnea, epiglottis, hypopharynx, systematic review, surgery, snoring, positional therapy, continuous positive airway pressure. Level of Evidence: NA. Laryngoscope, 126: , 2016 From the Division of Sleep Surgery, Department of Otolaryngology Head and Neck Surgery, Stanford University Medical Center (C.T., S.Y-C.L., L.K.H., R.C.); the the Division of Sleep Medicine, Department of Psychiatry and Behavioral Sciences, Stanford Hospital and Clinics (M.C.); the the School of Medicine, Stanford University (C.T., M.C., S.Y-C.L., R.C.), Stanford, California; the the Division of Sleep Surgery and Medicine, Department of Otolaryngology Head and Neck Surgery, Tripler Army Medical Center (M.C.), Honolulu, Hawaii, U.S.A.; the the Department of Otolaryngology, Head and Neck Surgery, Cathay General Hospital (L-K.H.); the School of Medicine, Fu Jen Catholic University (L-K.H.), Taipei, Taiwan Received June 5, 2015, Editor s Note: This Manuscript was accepted for publication July 27, The authors have no funding, financial relationships, or conflicts of interest to disclose. Send correspondence to Carlos Torre, MD, Department of Otolaryngology Head and Neck Surgery, Division of Sleep Surgery, Stanford University, 50 Broadway St., Pavilion B, 2nd Fl, Redwood City, CA ctorreleon22@gmail.com DOI: /lary INTRODUCTION Obstructive sleep apnea (OSA) is a disorder caused by the repetitive collapse of the upper airway during sleep, resulting in either partial or complete airflow obstruction. 1 Treatment with continuous positive airway pressure (CPAP) is the first line of treatment for patients with OSA. 2 Despite its proven efficacy, a significant number of patients cannot tolerate this form of treatment and seek other alternatives such as surgery and/or oral appliances. Surgery has been proven to be an effective form of treatment that reduces cardiovascular morbidity and mortality. 5 It can also improve neurocognitive symptoms in patients with OSA. As the role of surgery in the treatment of OSA continues to evolve, new tools have been developed to improve patient selection and the types of procedures that will be offered to them. One such tool is drug-induced sleep endoscopy (DISE), which has become an important part of the armamentarium of surgeons to evaluate their OSA patients. 6 The use of DISE has led to better understanding of this complex condition and the key factors that play a role in it. One such factor is epiglottis collapse, which through DISE has been found to occur more frequently than previously described in the literature, and of which little is known regarding its role in OSA. 7,8 Laxity of the epiglottis is commonly discussed in the pediatric literature as one of the possible presentations of congenital laryngomalacia 9 ; however, the adult form is a rare entity that has not been well described. 10 The majority of reported cases are secondary to neurological injuries, head and neck surgery, or trauma

2 Fig. 1. Inclusion criteria. Epiglottis collapse during sleep has been estimated to occur in around 12% of adult patients with OSA. 15 Based on a previous DISE study performed at our institution, epiglottis collapse may occur more frequently than previously reported in the literature. 16 Currently, there is a lack of good understanding about the relationship between epiglottis collapse and OSA and what the most effective way to treat it is. In this study, we sought to systematically review the international literature evaluating the role of the epiglottis in snoring and obstructive sleep apnea and to explore possible treatment options available. MATERIALS AND METHODS Protocol This study is exempt from Stanford Investigational Review Board approval because all the included studies are previously published in the literature and no new data is being provided by this review. This review was not registered in any systematic review protocol registry. Study Eligibility Criteria Study designs included in the searches for this systematic review included published abstracts; posters; case reports; case series; case controls; and cohort, randomized, and randomized controlled trials. Search In order to maximize the identification of potentially relevant studies, multiple search terms were utilized to include variations of the keywords epiglottis and supraglottis. The focus of this article was epiglottis; therefore, supraglottis was searched, but only studies reporting outcomes for epiglottis were included. An example of one search (PubMed): (((Epigl*) OR (Supraglot*)) AND (sleep OR snor* OR collapse OR Continuous Positive Airway Pressure [Mesh])). Study Selection For inclusion criteria, studies included in this review are those which reported the following: 1) adult patients ( 18 years old) who were diagnosed with sleep disordered breathing (SDB); 2) medical or surgical interventions were used to manage the SDB; 3) studies reporting pre- and posttreatment polysomnographic data, quality of life, sleepiness data, or snoring data; ) outcomes compared are either the patients serving as their own controls (posttreatment minus pretreatment) or the patients were compared to a separate control group (case control study); 5) prevalence of epiglottis collapse in OSA patients was presented; 6) studies reporting the role of the epiglottis in snoring and/or OSA; 7) studies reporting treatment options for epiglottis collapse; and 9) studies reporting epiglottis collapse secondary to CPAP use (Fig. 1). Exclusion criteria consist of the following: 1) studies in children; and 2) studies reporting findings for the supraglottis without any subcategorization of findings for the epiglottis. Information Sources The databases searched included PubMed, Scopus, Embase, Google Scholar, Book Citation Index-Science, CINAHL, Conference Proceedings Citation Index-Science, The Cochrane Collaboration Databases, and Web of Science. 516 Data Collection Process and Variables The searches were performed independently by authors (C.T. and C.T.). Year ranges for each of the databases was from the first year of each database through March 5, The data outcomes that were collected included: 1) demographic data

3 TABLE I. Prevalence of Epiglottis Collapse of Included Studies. Author, Year Number of Subjects Evaluation Tools % of Epiglottis Collapse Pattern and Percentage of Epiglottis Collapse Level of Evidence Catalfumo et al., Awake 11.5% 11.5% A-P collapse Nasoendoscopy Lan et al., DISE 2.2% 12.5% partial A-P collapse 26.6% complete A-P collapse 3.1% lateral complete collapse Cavaliere et al., DISE 22.7% 13.6% A-P collapse 9.1% lateral collapse Ravesloot et al., DISE 38% 12% partial A-P collapse 16% complete A-P collapse 2% partial lateral collapse 8% complete lateral collapse Koutsourelakis et al., DISE 73.5% Responders to surgery: 3.% complete A-P collapse 26.1% partial A-P collapse.3% lateral collapse 73% Nonresponders to surgery: 65.% complete A-P collapse 3.8% partial A-P collapse 3.8% lateral collapse Fernandez-Julian et al., DISE 36.% 36.% epiglottis collapse Awake 28.% 28.% epiglottis collapse Nasoendoscopy Zhang et al., DISE 9.7% 9.7% epiglottis collapse 2 Golz et al., DISE 25.7% 1.% isolated epiglottis collapse 11.3% multiple level collapse (including epiglottis) Lin et al., DISE 66.7% 66.7% active epiglottis collapse 9.9% passive epiglottis collapse (displacement of epiglottis due to tongue base) Woodson, DISE 15% 15% isolated epiglottis collapse A-P 5 antero-posterior; DISE 5 drug-induced sleep endoscopy. 2 such as patient ages (in years) and body mass index (BMI) in kilograms per meter squared (kg/m2), 2) polysomnographic variables (i.e., apnea-hypopnea index [AHI], lowest oxygen saturations [LSAT], and respiratory disturbance index [RDI]), 3) druginduced sleep endoscopy findings, ) imaging and cephalometric data, 5) CPAP therapy data, and 6) subjective and objective snoring data. Data Pooling No meta-analysis was performed because there were insufficient data from the included studies. Therefore, the risk of bias for individual studies and across studies could not be assessed. RESULTS Prevalence of Epiglottis Collapse There is only one study identified that has exclusively studied epiglottis collapse in OSA patients (Table I). In a study published by Catalfumo et al., the authors used awake fiberoptic endoscopy to evaluate 10 patients with persistent OSA after undergoing uvulopalatopharyngoplasty (UPPP). 15 They found that 11.5% of these patients had an abnormal position of the epiglottis because it was retrodisplaced against the posterior pharyngeal wall at the level of the hypopharynx during inspiration. Five other case reports described OSA secondary to a lax epiglottis that caused airway obstruction by collapsing into the laryngeal inlet during inhalation in awake patients ,17,18 A number of studies involving DISE have indirectly reported their findings regarding epiglottis collapse in OSA patients (Table I). In a study published by Lan et al. that correlated DISE findings with BMI and objective polysomnography variables in 6 patients with OSA, the authors noted that 12.5% and 26.6% of the patients had partial and complete anteroposterior epiglottis collapse, respectively. 16 None had partial lateral epiglottis collapse and 3.1% had complete lateral collapse. In another study by Cavaliere et al., in which they compared the degrees and patterns of airway obstruction in awake endoscopy versus DISE in

4 patients with OSA, the authors found that 22.7% (N 5 15) of patients showed an involvement of the epiglottis that was not assessable during wakefulness. 7 Of those, 13.6 % (N 5 9) had AP collapse and 9.1% (N 5 6) had lateral collapse. Ravesloot et al. evaluated 100 consecutive patients undergoing DISE and found that 12% and 16% of the patients had partial and complete AP collapse, respectively, and 2% and 8% had partial and complete lateral collapse, respectively. 19 Koutsourelakis et al. reported on 9 OSA patients who were evaluated using DISE before upper airway surgery and found that a total of 36 of the patients (73.5%) had some degree of epiglottis collapse. 20 In the group of responders, 3.% (N 5 10) had complete AP collapse, 26.1% (N 5 6) had partial AP collapse, and one had partial lateral collapse. 20 In the group of nonresponders, 65.% (N 5 17) had complete AP collapse, 3.8% (N 5 1) had partial AP collapse, and 3.8% (N 5 1) had partial lateral collapse. Fernandez-Julian et al. compared surgical recommendations in 162 patients based on DISE versus awake examination. 18 During DISE, the authors found that the epiglottis was involved in 36.% (N 5 59) of patients, whereas during the awake examination it ranged between 2.1% (N 5 39) and 28.% (N 5 6). Zhang et al. studied the findings of DISE and upper-airway computed tomography (CT) in 62 patients and found that 9.7% (N 5 6) had epiglottis collapse, but that none of the CT findings significantly differed between individuals with and without epiglottis collapse. 21 Golz et al. found that 8 out of 187 patients examined using nasopharyngoscopy during sleep had retrodisplacement of the epiglottis. 22 Of these, 27 had isolated epiglottis collapse, whereas 21 had airway collapse at different sites in addition to the epiglottis. Lin et al. found that 66.7% (N 5 26) out of 39 patients had more than 75% of active epiglottis collapse, but that in 9.9% the tongue base was causing posterior displacement of the epiglottis. 23 Kent et al. identified 35 patients with CPAP intolerance or incomplete response to oral appliances and found that 31.% (N 5 11) had epiglottis collapse. 2 Lastly, Woodson performed 117 DISE studies to describe luminal airway characteristics using visible landmarks identifiable on endoscopy and noted that 16% of patients had isolated obstruction from a ptotic epiglottis. 8 Treatment of Epiglottis Collapse Continuous Positive Airway Pressure. The role of CPAP is to stent the upper airway through the application of continuous positive pressure. In the case of primary epiglottis collapse, CPAP may aggravate airway obstruction by further pushing the epiglottis down into the laryngeal inlet. Dedhia et al. showed that the majority of adult patients who are unable to tolerate CPAP have multilevel obstruction, of which 15% presented with primary epiglottis obstruction of the hypopharynx. 25 In a study published by Shimohata et al., the authors reported findings for 17 patients with multiple system atrophy of which 12 presented with a floppy epiglottis (FE) during DISE. 26 Of those with severe FE (N 5 3), none improved with CPAP treatment; while in those with mild FE (N 5 9), CPAP caused severe FE 518 during inspiration, with decreasing oxygen saturation levels in two patients and improved airway obstruction in the remaining seven patients. Three more case reports were identified that discuss CPAP intolerance in patients with epiglottis collapse (Table II). 12,13,27 Epiglottis Surgery. Catalfumo et al. reported that when partial epiglottectomy was combined with other procedures such as UPPP, the cure rate of OSA could be increased from 50% to about 60% to 65%. 15 Kenmore et al. reported the case of a patient with inspiratory dyspnea due to a floppy epiglottis where they performed a V-shaped epiglottidectomy of the upper-central part with a laser, leaving the inferior aspect intact to prevent aspiration. 28 Two studies reported their experience with performing epiglottectomy by using diathermy. 29,30 Oluwasanmi et al. described their outcomes for one OSA patient and three snorers who presented with a floppy epiglottis. 30 Using diathermy, they resected the epiglottis just above the floor of the vallecula, which lead to complete resolution of the snoring. In the case of the OSA patient, epiglottectomy was performed in conjunction with UPPP, which led to a 50% improvement in the patient s AHI score (Table II). Epiglottectomy has also been performed using carbon dioxide (CO2) laser. 22,29,30 In a study published by Golz et al., 27 patients were found to have an abnormal epiglottis that was obstructing into the hypopharyngeal space; the patients were treated with partial epiglottectomy using CO2 laser. 22 The overall decrease in the RDI, as measured using polysomnographic studies, decreased from to events/hour, whereas the overall improvement in the oxygen saturation level went from 66% % preoperatively to 95% % postoperatively. In a study published by Bourolias et al., cartilage reshaping was accomplished in cadaveric larynx specimens by irradiating the superficial layers of the cartilage with CO2 laser, which allowed the epiglottis to acquire a new shape that was no longer obstructing the laryngeal inlet. 31 In a study published by Mickelson et al. in which they performed midline glossectomy and epiglottidectomy using a CO2 laser in 12 patients who had failed previous UPPP, they demonstrated the highest success rates in patients who are not morbidly obese. 32 In the group of responders (N 5 3) with an average BMI of 30.7 kg/m2, the RDI decreased from to events/hour, and the LSAT improved from 83.0% 6 6.1% to 91.3% 6 3.2%. In the nonresponder group (N 5 9), in which the average BMI was 37.8 kg/m2, the RDI decreased from to events/hour, and the LSAT improved from 59.5% % to 73.% %. In a study published by Lin et al., in which 26 patients had more than 75% of active epiglottis collapse, they found that half of them (N 5 13) responded successfully to transoral robotic surgery (TORS)-assisted tongue base reduction and partial epiglottectomy. 23 Toh et al. published their results for TORS-assisted tongue base reduction with partial epiglottectomy and palatal surgery and found that cure (AHI < 5 events/hour) was achieved in seven patients, success (AHI < 20 events/ hour combined with 50% reduction in presurgical

5 TABLE II. Treatment of Epiglottis Collapse in OSA Subjects in Included Studies. Continuous Positive Airway Pressure Level of Evidence Dehdia et al., % of subjects unable to tolerate CPAP presented with primary epiglottis obstruction Shimohata et al., % (12 of 17) presented with FE 9 of 17 mild FE: CPAP caused severe FE during inspiration (2 of 17) Improved by CPAP (7 of 17) 3 of 17 severe FE: none improved with CPAP Verse et al., 1991 Case report: Intolerant to CPAP treatment due to epiglottis collapse Andersen et al., 1987 Case report: Intolerant to CPAP treatment due to epiglottis collapse Chetty et al., 199 Case report: Intolerant to CPAP treatment due to epiglottis collapse Epiglottis Surgery N Procedures Results Complication Catalfumo et al., Partial epiglottectomy 1 other procedures (e.g., UPPP) Kenmore et al, V-shaped epiglottidectomy (using KTP laser) Harries et al., Case report diathermy to the lateral edge of epiglottis and aryepiglottic folds Oluwasanmi et al., 2001 Epiglottectomy (using monopolar diathermy) Golz et al., Partial epiglottectomy using CO2 laser Mickelson et al., Epiglottidecotmy 1 midline glossectomy using CO2 laser (12 cases that had failed UPPP) Lin et al., TORS-assisted partial epiglottectomy 1 tongue base reduction Toh et al., TORS-assisted tongue base reduction 1 partial epiglottectomy 1 palatal surgery Sleep apnea index decreased from to Epiglottis did not prolapse into the posterior pharyngeal wall during normal inspiration 6 months postoperatively No significant postoperative complications No aspiration or discomfort in the throat after the surgery Epiglottis did not prolapse postoperatively No significant postoperative complications Snoring: complete resolution in all cases OSA cases: 50% improvement of AHI Decreased AHI from to events/hr Oxygen saturation level went from 66% % preoperatively to 95% % postoperatively Responders (BMI 30.7 kg/m2): RDI decreased from to events/hr. Lowest oxygen saturation improved from 83.0% 6 6.1% to 91.3% 6 3.2%. Nonresponders (BMI 37.8 kg/m2): RDI decreased from to events/hr. Lowest oxygen saturation improved from 59.5% % to 73.% 3.8.6%. 1 patient had occasional aspiration of liquid, which is still present 2 years postoperation No significant postoperative complications 1 case had minor bleeding 3 days after surgery No other patients had signify postoperative complications Responders: 50% (13 of 26) 3 cases (7.7%) had oropharyngeal scarring causing dysphagia 3 cases (7.7%) continued to experience minor taste alterations more than 1 year postsurgery Surgical cure: 7 of 20 Surgical success: 11 of 20 Failure: 2 of 20 1 patient (5%) had tonsillar bleeding 100% patients had temporary anterior tongue numbness and soreness 519

6 TABLE II. (Continued) Continuous Positive Airway Pressure Level of Evidence 7 of 20 patients (55%) had temporary change in taste 1 of 20 patients (5%) had slight difficulty in swallowing Sorrenti et al., UPPP 1 tongue base reduction 1 hyoepiglottoplasty Den Herder et al., HTP 17 patients had 2nd HTPafter an unsuccessful UPPP 1 patients had primary HTP Success rate: 100% (AHI decreased from to events/hr). Responder: 29 of 31 Nonresponders: 2 of 31 (2 had floppy epiglottis, afterward treated with epiglottectomy) None of the patients had primary postoperative bleeding from the tongue base Videofluoroscopy showed swallowing abnormalities in 3 patients None of the patients demonstrated any sign of penetration and/or aspiration Tracheotomy performed in one patient because of a compromised airway caused by postoperative bleeding Positional Therapy Safiruddin et al., % positional apnea: lateral positioning of the head decreased the frequency of complete A-P collapse of velum, tongue base, and epiglottis 33% nonpositional apnea: lateral positioning of the head decreased the frequency of complete A-P collapse of tongue base and epiglottis Oral Appliances Kent et al., Eleven (31.%) patients had complete epiglottic obstruction. With oral appliances treatment, seven (20%) had persistent complete epiglottic obstruction. A-P 5 antero-posterior; AHI 5 apnea-hypopnea index; BMI 5 body mass index; CPAP 5 continuous positive airway pressure; FE 5 floppy epiglottis; HTP 5 hyoidthyroidpexia; OSA 5 obstructive sleep apnea; RDI 5 respiratory disturbance index; TORS 5 transoral robotic surgery; UPPP 5 uvulopalatopharyngoplasty. 520

7 AHI) was achieved in 11 patients, and failure was observed in two patients. 33 In a study published by Sorrenti et al., the authors report a 100% success rate in 10 male patients with severe OSA treated with single-phase UPPP plus tongue base reduction and hyoepiglottoplasty. 3 Mean AHI decreased from to events/hour, whereas the mean oxygen saturation improved from 77% 6 6.2% to 90% 6 3%, and the time of sleep spent below 90% oxygen saturation improved from 53% % to 7.3% 6 8%. Herder et al. published their results for hyoidthyroidpexia, which was performed in 31 patients with moderate-to-severe OSA, and found that the two patients who had a floppy epiglottis were nonresponders. The authors concluded that patients with hypopharyngeal obstruction who have a floppy epiglottis are not good candidates for this procedure. 35 Positional Therapy and Oral Appliances In a study published by Victores et al., they found that both the epiglottis and the tongue base caused obstruction twice as frequently in the positional OSA groups (6% and 7%, respectively) as compared with the nonpositional OSA groups (36% and 36%, respectively). 36 They also identified the tongue base and the epiglottis as the primary sites of airway size improvement when patients were evaluated in the lateral position as compared to the supine position. Safiruddin et al. reported that lateral positioning of the head is associated with decreased frequency of complete anteroposterior collapse at tongue base and epiglottis in patients with both positional and nonpositional OSA. 37 Finally, Kent et al. found in their study that out of 11 patients with epiglottis collapse, only four of them were successfully treated with oral appliances for this problem. 2 Role of the Epiglottis in Snoring Beeton et al. proposed that vibratory forces produced at the level of the tongue base and the epiglottis experience low-frequency absorption. 38 Agrawal et al. performed sound frequency analysis of different snoring sites and found that epiglottis snoring has a peak frequency of 90 hertz (Hz), whereas tonsillar vibrations have a peak frequency of 170 Hz. 39 Won et al. observed that there is an increase in pitch frequency in tongue base and epiglottis snoring compared with soft palate snoring. 0 Quinn et al. carried out sleep nasoendoscopy in 50 adult patient with primary snoring. 1 Palatal flutter snoring only was found in 70% of patients. It was combined with epiglottis, tonsillar, and tongue base snoring in 10%, 8%, and 2%, respectively. The epiglottis was the sole site of snoring in 2% of the patients, thus implicating the epiglottis in 12% of adult snorers. Meanwhile, in another study published by Saunders et al., the authors were unable to identify any patients with epiglottis snoring in 35 patients undergoing sleep nasoendoscopy. 2 DISCUSSION The results of this systemic review confirm that collapse of the epiglottis in OSA patients occurs more frequently than previously reported. Before the advent of DISE, the prevalence of this epiglottis collapse was estimated to be 12% of OSA patients based on awake examinations, which led to an underestimation of the problem. 15 However, since the DISE classification systems have been published, the prevalence of epiglottis collapse has been much higher than previously thought. 7,16,18 20 We now know that obstruction patterns observed during wakefulness and during induced sleep may not correlate. Studies identified in this review have demonstrated that epiglottis collapse can be seen during DISE even when there is no evidence of it in the awake examination using flexible laryngoscopy. 7,16,18 20 Studies have also demonstrated that anteroposterior epiglottis collapse occurs more frequently than lateral collapse. 7,16,18 20 Additionally, epiglottic collapse is more commonly found in patients who do not respond to upper airway surgery for OSA. 20,35 Rarely do we see OSA patients with isolated epiglottis collapse, which explains why we currently lack enough evidence to support any treatment that may specifically address this issue. Since its advent as a tool for the treatment of OSA, the scope of surgery has evolved to address multiple areas of obstruction simultaneously. 3 5 For this reason, treatment of epiglottis collapse in patients with OSA is generally bundled into procedures that target other areas of obstruction as well. The studies presented in this review do not describe a solitary technique that is consistently used to address epiglottis collapse. Also, none of the studies found examined epiglottis collapse before and after a particular intervention; thus, there is no data demonstrating just how effective surgical treatment is. The first line of treatment for OSA continues to be CPAP. 2 Previous accounts suggest that CPAP may be ineffective in the treatment of OSA patients who have epiglottis collapse because it will further push the epiglottis down into the laryngeal inlet; however, no studies have looked directly at the effect of CPAP in the prevention of epiglottis collapse, and most of the information we have about how CPAP may accentuate this problem is based on case reports. 12,13,25 27 It can be hypothesized that CPAP could cause worsening of OSA if there is a floppy epiglottis because the forced pressure could cause retrodisplacement of the epiglottis to the point where it causes complete occlusion at the level of the laryngeal inlet. Positional therapy, on the other hand, does seem to consistently offer good results in treating epiglottis collapse and to be more effective than oral appliances in OSA patients with this problem. 2,36,37 Resection of the epiglottis provides the most effective and predictable solution in cases when a floppy epiglottis collapses and obstructs the airway during sleep. 15,22,23,28 30,32,33 Studies evaluating epiglottectomy in snoring patients with a floppy epiglottis have shown that the procedure decreased their snoring. 30 In patients with OSA, epiglottectomy performed in conjunction with 521

8 other procedures can lead to significant improvement in the severity of the disease. 15 Hyoepiglottoplasty combined with UPPP and partial glossectomy has been reported to offer a 100% success rate in select patients. 3 Meanwhile, hyoid advancement or suspension performed in isolation has not been shown to effectively treat epiglottis collapse. 35 The epiglottis has also been implicated in 12% of cases of snoring and can be the sole site of snoring or may contribute to snoring in combination with other sites such as the palate, base of tongue, and/or lateral pharyngeal walls. 15 Therefore, the differentiation of palatal versus nonpalatal snoring is very important to predict whether palatal surgery would be curative of this problem. Several studies have tried to analyze sound acoustically in order to make this distinction and have found that sounds originating from the hypopharynx have a higher peak frequency and pitch. Limitations This study has limitations. First, studies that we did not identify possibly could have met criteria despite our best effort. Because there was insufficient data for a meta-analysis, publication bias could not be assessed; therefore, it is possible that studies demonstrating minimal improvement or worsening of OSA after epiglottis surgery never made it to publication. However, we believe that it is reasonable to address patients who have a floppy epiglottis by performing an appropriately targeted procedure if the patients have failed medical management (e.g., CPAP, positional therapy, etc.) Lastly, this study is limited by the lack of published studies, and we would encourage future researchers to publish their findings. CONCLUSION Knowledge regarding the role of the epiglottis in adult OSA patients is limited. The prevalence of epiglottis collapse in patients with OSA is likely to be higher than previously described because there is substantial disagreement between awake examination and DISE findings. Studies have reported an improvement in multilevel surgery for OSA outcomes when epiglottis surgeries are combined with other procedures. CPAP may be effective in patients with a mildly or moderately floppy epiglottis; however, it could be ineffective when there is a severely floppy epiglottis. Additional research is needed about the subject because available data is limited. Acknowledgments Carlos Torre, MD, was responsible for the conception, design, analysis, and drafting of the work; revising the work; and reviewing the article. Stanley Liu, MD, and Robson Capasso made substantial contributions to the acquisition of data for the work and drafting the work. Leh-Kiong Huon, MD, made substantial contributions to data analysis and interpretation of data for the work and revised the work critically for important intellectual content. 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