The Laryngoscope
C 2014 The American Laryngological,
V
Rhinological and Otological Society, Inc.
Surgical Planning After Sleep Versus Awake Techniques
in Patients With Obstructive Sleep Apnea
Enrique Fern
andez-Juli
an, MD, PhD; Miguel Angel
Garcıa-Perez, PhD; Javier Garcıa-Callejo, MD, PhD;
Felipe Ferrer, MD, PhD; Francisco Martı, MD, PhD; Jaime Marco, MD, PhD
Objective/Hypothesis: This study examined correlations between surgical recommendations based on either druginduced sleep endoscopy (DISE) or common awake examination methods in patients with obstructive sleep apnea syndrome
(OSAS).
Study Design: Prospective, blinded, clinical trial at a university hospital.
Methods: An otorhinolaryngologist designed surgical plans for patients with OSAS after clinical examination, lateral
cephalometry, the M€
uller maneuver, and Friedman staging. A second otorhinolaryngologist blinded to the previous plans
made surgical recommendations after DISE. A third person tested agreement between the two sets of plans using Cohen’s
kappa statistic and the chi-squared test.
Results: One hundred and sixty-two patients (15 females, 147 males) completed the protocol. Good correlation was
observed between DISE and Friedman staging regarding recommendations for isolated oropharyngeal or multilevel surgery
(kappa 5 0.61). Correlations between DISE and clinical examination, lateral cephalometry, and the M€
uller maneuver regarding
surgical procedures on specific structures contributing to upper airway obstruction ranged from fair for velum/tonsil surgery
(k 5 0.41–0.60) to poor (k 5 0.01–0.20) for tongue-base, lateral pharyngeal wall, and epiglottal surgery. The most informative
value was DISE versus clinical evaluation, lateral cephalometry, and the M€
uller maneuver, which changed surgical recommendations concerning the structures contributing to hypopharyngeal or laryngeal obstruction in > 40% of patients.
Conclusions: Our results indicate that DISE provides more information about the anatomical locations and pattern of
obstruction, particularly regarding the specific structures contributing to hypopharyngeal and laryngeal obstruction. DISE
changes surgical decision making compared to awake evaluation methods.
Key Words: Drug-induced sleep endoscopy, clinical examination, lateral cephalometry, M€
uller maneuver, Friedman staging system, surgical planning.
Level of Evidence: 4.
Laryngoscope, 124:1970–1974, 2014
INTRODUCTION
Obstructive sleep apnea syndrome (OSAS) is characterized by repetitive episodes of total or partial
obstruction of the upper airway during sleep, usually
associated with daytime sleepiness and neurocognitive
and cardiovascular consequences.1,2
The gold standard treatment for OSAS is continuous positive airway pressure. However, some patients do
not use these devices, or they use them insufficiently.
Alternative and well-studied options are surgery, oral
appliances, and weight loss.
The results of isolated uvulopalatopharyngoplasty
(UPPP)3 and multilevel operative therapy4 have been
From the Otorhinolaryngology Department (E.F-J., J.G-C., F.F., J.M.);
the Department of Anesthesiology (F.M.), Hospital Clınico Universitario,
Spain; and the Institute of Health Research INCLIVA and Department
of Genetics (M.A.G-P.), University of Valencia, Valencia, Spain.
Editor’s Note: This Manuscript was accepted for publication
December 30, 2013.
The authors have no funding, financial relationships, or conflicts
of interest to disclose.
Send correspondence to Enrique Fern
andez-Juli
an, MD, Department of Otorhinolaryngology, Hospital Clınico Universitario, Avda,
~ ez 17, 46010 Valencia, Spain. E-mail: [email protected]
Blasco Ib
an
DOI: 10.1002/lary.24577
Laryngoscope 124: August 2014
1970
disappointing in many circumstances. This situation may
stem from many factors. Airway obstruction during sleep is
not a completely anatomical problem, and surgery designed
to achieve only anatomical modification is thus insufficient.
Failure to identify the anatomical regions of upper airway
obstruction (oropharynx, hypopharynx, or larynx) and specific structures (soft palate, tonsils, lateral pharyngeal
walls, tongue base, and/or epiglottis) contributing to this
obstruction are other factors. Identifying the anatomical
locations and the pattern of obstruction and integrating
this anatomy into proper surgical technique are essential
for improving effectiveness and minimizing morbidity. Several authors have shown that improper selection criteria
can explain the failure rate of surgery for OSAS.5,6
A variety of methods can be used to assess the anatomical locations of upper airway obstruction, but none
can be considered a standard diagnostic method. Clinical
examination (CE), lateral cephalometry (LC), and the
M€
uller maneuver (MM) are applied during wakefulness
to discover anatomical features of the skeleton and pharynx that may contribute to structural vulnerability and
OSAS pathophysiology.
Fujita7 developed a system for the classification of
type I (oropharyngeal), type II (oropharyngeal and hypopharyngeal), and type III (hypopharyngeal) OSAS.
ndez-Julia
n et al.: Surgical Planning: DISE Versus Awake Techniques
Ferna
Later, Friedman et al.8 instituted the Friedman
staging system (FSS), which is based on tonsil size, palate position in relation to the tongue, and body mass
index (BMI). They suggested that the FSS could be helpful in predicting UPPP outcomes (80.6%, 37.9%, and
8.1% success rates in patients with stage I, stage II, and
stage III OSAS, respectively).8 The FSS is used widely
to select patients for palatal surgery and to confirm the
presence of multilevel obstruction, thereby identifying
patients who could benefit from multilevel surgery.
These evaluation methods are subjective and limited because they are performed in the awake state
when increased muscle tone can confound the results.
Therefore, correlation with an objective test performed
during sleep to determine the anatomical locations of
obstruction is needed.
In 1991, Croft and Pringle9 described sleep nasendoscopy, a more realistic method of tridimensional evaluation of the upper airway during pharmacologically
induced sleep. This technique is also known as druginduced sleep endoscopy (DISE). To date, many descriptions of the diagnostic findings of DISE have been
published. However, relatively few studies10 has shown
that DISE versus awake techniques provides more clinical information to assess airway function and collapse,
and assists in surgical planning for OSAS patients.
The purpose of this study was to determine the
correlation between surgical recommendations for
anatomical locations of upper airway obstruction based
on commonly used awake-examination methods (CE,
LC, MM, and FS) and those based on DISE in OSAS
patients.
MATERIALS AND METHODS
This blinded prospective study included patients with
moderate to severe OSAS diagnosed by full attended nocturnal
polysomnography at the Clinical University Hospital of Valencia
between October 2011 and April 2013. The study was approved
by the hospital’s research foundation, and patients provided
written informed consent before participating in the study.
An otorhinolaryngologist designed surgical plans after
evaluation of patients in the waking state. A second otorhinolaryngologist blinded to the previous conclusions designed surgical plans after DISE. Both otorhinolaryngologists specialize in
the management of OSAS patients and all surgical planning,
followed a standardized departmental protocol. Techniques
applied included UPPP/tonsillectomy, tongue-base suspension,
tongue-base radiofrequency, lingual tonsillectomy, hyoid suspension, and partial epiglottidectomy, as there was obstruction due
to hypertrophic soft palate/tonsils, anteroposterior tongue-base
prolapse, hypertrophic tongue base, hypertrophic lingual tonsils, collapse of the lateral pharyngeal walls/epiglottis, or floppy
epiglottis, respectively. A third person compared the two surgical plans and treatment recommendations.
Clinical Examination
An elongated or hypertrophic soft palate or hypertrophic
palatine tonsils extending beyond the anterior pillars were
defined as oropharyngeal obstruction. Hypopharyngeal obstruction was defined as a hypertrophic tongue base or lingual tonsils, preventing visualization of the entire larynx—including the
arytenoids—by supine fiber-optic nasopharyngoscopy. Apposi-
Laryngoscope 124: August 2014
tion of the epiglottis to the posterior pharyngeal wall was
defined as laryngeal obstruction.
Lateral Cephalometry
On LC, oropharyngeal, hypopharyngeal, and laryngeal
obstruction were defined as increased distance between the posterior nasal spine and uvula or elongated soft palate (PNS–
U > 40 mm), narrow posterior airway space (PAS < 10 mm), and
reduced distance between the epiglottis apex and lower pharyngeal wall (EA–LPW < 6 mm), respectively.11
M€
uller Maneuver
The MM was carried out while the patient was awake in
dorsal decubitus. Oropharyngeal obstruction was defined as
apposition of the soft palate to the posterior pharyngeal wall or
midline contact between the palatine tonsils leading to > 50%
obstruction. Hypopharyngeal obstruction was defined as anteroposterior tongue-base prolapse leading to > 50% retrolingual
obstruction or midline contact between the lateral pharyngeal
walls. Posterior displacement of the entire epiglottis toward the
glottic inlet was defined as laryngeal obstruction.12
Friedman Staging
The FSS was used to classify OSAS as stage I, stage II, or
stage III. Oropharyngeal surgery (UPPP) alone was indicated
for patients with stage I OSAS, and multilevel surgery was
indicated for those with stage II/III OSAS.8
Drug-induced Sleep Endoscopy
DISE was performed in an operating room with the
patient in the supine position. Oxygen saturation and cardiac
rhythm were monitored, and propofol (Diprivan; AstraZeneca
International PLC, London, UK) was administered with the aid
of target-controlled infusion (TCI) by a pump (Diprifusor TCI
system, AstraZeneca International PLC).
Oropharyngeal obstruction was defined as anteroposterior
or concentric collapse of the soft palate or lateral collapse of the
palatine tonsils. Hypopharyngeal obstruction was defined as
anteroposterior tongue-base prolapse or midline contact
between the lateral pharyngeal walls. Laryngeal obstruction
was defined as prolapse of the arytenoids or epiglottis toward
the glottic inlet during aspiration, sometimes secondary to
tongue base pressure.
Statistical Analysis
The data were recorded and analyzed using the Statistical
Package for Social Sciences (SPSS; SPSS Inc., Chicago, IL). The
chi-squared test and Cohen’s kappa statistic were used to test
agreement in surgical predictions based on DISE and other
evaluation techniques. The strength of agreement was classified
as excellent (k 5 0.93–1.00), very good (k 5 0.81–0.92), good
(k 5 0.61–0.80), fair (k 5 0.41–0.60), slight (k 5 0.21–0.40), or
poor (k 5 0.01–0.20).13 Ninety-five percent confidence intervals
(CIs) were calculated for all kappa values to indicate the reliability of estimates. Statistical significance was accepted at
P < 0.05.
RESULTS
Between October 2011 and April 2013, 184 patients
were enrolled in the study. The MM could not be performed in 12 patients, four patients rejected DISE, and
ndez-Julia
n et al.: Surgical Planning: DISE Versus Awake Techniques
Ferna
1971
According to the FSS, patients were classified as
having stage I (n 5 31, 19.1%), stage II (n 5 109, 67.3%),
and stage III (n 5 22, 13.6%) OSAS. DISE and FSS predicted isolated oropharyngeal surgery in 28.4% (n 5 46)
and 19.1% (n 5 31) of patients and multilevel surgery in
71.6% (n 5 116) and 80.9% (n 5 131) of patients, respectively. The Pearson chi-squared test showed significant
relationships between surgical predictions of isolated
oropharyngeal and multilevel surgery based on DISE
and FSS (P < 0.0001). These predictions also showed
good agreement (k 5 0.613; 95% CI, 0.473–0.753).
The most informative value was DISE vs CE, LC,
and MM, which changed surgical recommendations concerning structures contributing to hypopharyngeal or
laryngeal obstruction in > 40% of patients.
Fig. 1. Distribution of specific structures contributing to upper airway obstruction. CE 5 clinical examination; DISE 5 drug-induced
€ller
sleep endoscopy; LC 5 lateral cephalometry; MM 5 Mu
maneuver.
sedation failed in six patients. A total of 162 patients
(15 females and 147 males) completed the protocol. The
mean age was 46.3 6 6.4 years, mean BMI was
28.1 6 3.2 kg/m2, and mean apnea-hypopnea index was
32.1 6 18.2/h. None of our patients had morbid obesity.
All techniques showed that retropalatal and retrolingual were the most common anatomical locations of
obstruction. CE and LC were unable to detect obstruction caused by the lateral pharyngeal walls (Fig. 1).
Pearson’s chi-squared test showed a significant relationship between surgical plans based on DISE and
those based on awake techniques (CE, LC, and MM) for
velum/tonsil surgery (P < 0.0001). However, no significant relationship between plans was found for surgery
involving the tongue base, lateral pharyngeal walls, or
epiglottis. Agreement between plans based on DISE and
awake techniques was fair (k 5 0.41–0.60) for velum/
tonsil surgery but poor (k 5 0.01–0.20) for tongue base,
lateral pharyngeal wall, and epiglottal surgery (Table I).
DISCUSSION
The aim of our study was to compare DISE versus
awake techniques in a group of OSAS patients who were
not morbidly obesity because several studies suggest
that a high BMI is a marker of poorer outcomes.4,14–17
On polysomnography, apnea is divided into so-called
obstructive sleep apnea (no airflow despite expenditure
of ventilatory effort) and central sleep apnea (absence of
both airflow and ventilatory effort). In standard OSAS
patients such as ours, few central sleep apneas (CSA)
are observed in polysomnograms and are appropriately
ignored because they are of no clinical significance.
Nevertheless, hypocapnic patients with primary CSA or
Cheyne Stokes, and hypercapnic patients with neuromuscular disorders or obesity hypoventilation syndrome
(OHS), often exhibit CSA. It is important to distinguish
among OSAS, OHS, and OSAS/OHS because treatments
can differ.
Upper airway collapse in OSAS patients results from
the interaction of static (craniofacial framework and
upper airway soft-tissue mass) and dynamic (neuromuscular tone and airflow) forces. The literature on upper airway obstruction in these patients usually refers to
oropharyngeal or hypopharyngeal segments, and some
TABLE I.
Correlations of Surgical Predictions Based on DISE and Awake Techniques for Specific Structures.
Pearson v2 test (DISE vs. indicated
awake technique)
Surgical Prediction
Velum/tonsils
Tongue base
Technique
n
Technique
DISE
126 (77.8%)
CE
112 (69.1%)
0.436
0.283–0.588
<0.0001
LC
MM
101 (62.3%)
115 (71.0%)
0.413
0.469
0.272–0.555
0.316–0.622
<0.0001
<0.0001
DISE
75 (46.3%)
n (%)
k
95% CI
P
CE
71 (43.8%)
0.028
20.126–0.182
0.719
LC
MM
82 (50.6%)
79 (48.8%)
0.149
0.085
20.003–0.301
20.069–0.238
0.057
0.280
Lateral pharyngeal
walls
DISE
65 (40.1%)
MM
62 (38.3%)
0.029
20.125–0.183
0.711
Epiglottis
DISE
59 (36.4%)
CE
LC
39 (24.1%)
41 (25.3%)
0.023
0.030
20.126–0.172
20.120–0.181
0.761
0.688
MM
46 (28.4%)
0.063
20.091–0.216
0.415
€ller maneuver.
CE 5 clinical examination; CI 5 confidence interval; DISE 5 drug-induced sleep endoscopy; LC 5 lateral cephalometry; MM 5 Mu
Laryngoscope 124: August 2014
1972
ndez-Julia
n et al.: Surgical Planning: DISE Versus Awake Techniques
Ferna
authors have considered the hypopharynx and tongue
base as a single unit.18 We believe that differentiation and
identification of obstructions due to the tongue base, lateral pharyngeal walls, and epiglottis are important
because treatment approaches differ. We examined three
anatomical regions of obstruction, each with specific anatomical structures contributing to obstruction: oropharynx (velum/tonsils), hypopharynx (tongue base and
lateral pharyngeal walls), and larynx (epiglottis).
The importance of determining the anatomical locations of upper airway obstruction in OSAS patients has
led to the development of numerous methods to improve
surgical success, but a lack of evidence has prevented
establishment of the best approach.
The most frequently used traditional methods
include static (CE and LC) and dynamic (MM) collapse
evaluation. These methods have shown limited value
because they are subjective and performed in the awake
state, when increased muscle tone can confound the
results and, more importantly, when sleep-related physiological factors cannot be evaluated.19 In natural sleep,
there is a reduction in genioglossus muscle tone during
NREM and REM sleep that is more pronounced in
OSAS than in normals, which may contribute to partial
or total collapse of the upper airway.20 Thus, upper airway collapse may be evaluated more reliably during
sleep than when the patient is awake.
After physical examination and endoscopy, the
Fujita classification may help exclude patients with
hypopharyngeal obstruction who are poor candidates for
UPPP.3 However, this classification system does not positively predict the anatomical location of obstruction
measured during sleep.21
Our results indicate that CE is the best predictor of
retropalatal vs retrolingual collapse during sleep. We
believe that visual inspection of the pharynx should be
done to rule out gross anatomical obstruction findings or
pathologies. However, although this technique is inexpensive, readily available, and easy to perform, visual
inspection is subjective. In addition, it is performed
while the patient is awake, when muscular tone and
respiratory drive may differ from those during sleep.22
Awake endoscopy has been used to assess upper airway narrowing in OSAS patients. However, slight agreement (k 5 0.09) in findings between two observers was
reported for endoscopies performed on 40 patients with
OSAS and/or snoring.23
LC has become a standard diagnostic tool for OSAS.
It is used to evaluate parameters contributing to upper
airway obstruction, such as elongated palate, diminished
PAS, and inferiorly positioned hyoid. However, LC is
more successful for the identification of a retrolingual
versus retropalatal collapse.24,25
In the present study, we observed fair and poor
agreement between DISE and LC findings with regard to
retropalatal and retrolingual obstruction, respectively.
These results differ from those of George et al.,26 perhaps
due to differences in average PNS–U and PAS values.
The main limitations of LC are that it shows a twodimensional image of the skeletal and soft-tissue anatomy of the head and neck during wakefulness, provides
Laryngoscope 124: August 2014
no information on lateral structures, and only evaluates
static collapse. However, it has a role in the evaluation
of maxillomandibular abnormalities. Neither CE nor LC
is able to identify lateral pharyngeal wall collapse, which
is primarily dynamic.
MM allows visualization of the entire upper airway
to exclude any other lesion. However, MM findings
depend on the subjective visual estimation of airway collapse (even when using a grading system); are limited
by the patient’s cooperation, coordination, and effort;27,28
and are not always representative of the sleep state
because this technique can produce false-positive
results.19 Sher et al.12 concluded that preoperative selection of OSAS patients by MM increases the likelihood of
UPPP success. Other investigators, however, have found
relatively low predictive efficacy of MM for UPPP success.29–31 Our data suggest that LC and MM can overestimate retrolingual collapse.
FSS also emphasizes anatomical findings. This
anatomy-based staging system is used widely to select
patients for palatal surgery and to determine the presence of multilevel obstruction, thereby identifying
patients who will benefit from multilevel surgery. Like
LC, FSS can help identify the obstruction patterns of
the upper airway. However, staging based on anatomic
findings is subjective, evaluates only static collapse,
assumes hypopharyngeal obstruction in patients with
stage II or III OSAS, and more importantly, is performed
while patients are awake, preventing evaluation of the
physiological events that occur during sleep. We found
good agreement in recommendations for oropharyngeal
or multilevel surgery based on DISE and FSS. However,
FSS is unable to identify the anatomical elements
responsible for hypopharyngeal obstruction, especially
the lateral pharyngeal walls and epiglottis.
DISE is a qualitative technique that allows for the
evaluation of upper airway obstruction during pharmacologically induced sleep. This technique changes sleep
architecture but allows respiratory assessment because
the main respiratory parameters evaluated in OSAS are
maintained.32 Several authors have shown that DISE
has the clinical power to improve UPPP results compared with historical controls.33–35 However, no standard
references exist to determine the anatomical locations of
upper airway obstruction during sleep.
We found remarkable disagreement between surgical plans based on DISE and awake techniques in OSAS
patients. The most relevant differences were shown with
respect to tongue-base, lateral pharyngeal wall, and epiglottal surgeries, for which plans based on DISE disagreed with those based on CE, LC, and MM in > 40% of
patients. These results are comparable to those of other
groups.36 Velum/tonsil and epiglottal surgeries were recommended more often after DISE than after CE, LC,
and MM. Tongue-base interventions were recommended
less often after DISE than after LC and MM. The identification of specific structures contributing to hypopharyngeal and laryngeal obstruction is important for the
selection of the appropriate surgical approach. Indeed,
Kezirian37 found that patients who had undergone hyoid
suspension showed no epiglottal obstruction during
ndez-Julia
n et al.: Surgical Planning: DISE Versus Awake Techniques
Ferna
1973
DISE. Moreover, some techniques commonly used to
treat hypopharyngeal obstruction, such as tongue-base
radiofrequency and genioglossus advancement, do not
address the collapse of the lateral pharyngeal walls. On
the other hand, partial epiglottidectomy may be indicated in some cases.
One limitation of our study is possible bias caused
by inter-rater variability (the awake and DISE examinations were performed by two different otorhinolaryngologists). Second, upper airway examinations during
wakefulness and DISE were performed in patients in
different bodily positions. Nevertheless, the upper airway changes following movements from sitting to supine
as well as lateral decubitus to supine.38 Third, none of
our patients had a BMI > 32 kg/m2 or an AHI > 45/h.
Therefore, the findings of this study cannot be safely
extrapolated to the general population of OSAS patients.
Finally, the reliability of DISE exam is good but
needs to be improved to reach the level of excellence
expected of most gold standard tests used in clinical
practice. Further, we emphasize the need for more objective, quantitative descriptors, as well as well-designed
research to establish DISE as a justified diagnostic tool
in sleep medicine. Our next goal is to explore if DISE
versus awake techniques allow us to improve the surgical outcomes of OSAS patients.
CONCLUSION
Our results indicate that DISE provides more information about the anatomical locations and pattern of
obstruction, particularly regarding the specific structures contributing to hypopharyngeal and laryngeal
obstruction. DISE changes surgical decision-making
compared to awake evaluation methods.
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