Obesity risk in anesthesia a nd surgery

Obesity ;predictors of outcome

STOP Questionnaire.A Tool to Screen Patients for Obstructive
Sleep Apnea .Anesthesiology 2008; 108:812–21
• OBSTRUCTIVE sleep apnea (OSA) is the most prevalent
breathing disturbance in sleep, affecting 2–26% of the
general population depending on sex, age, and the
definition of criteria.
• OSA is associated with significant morbidity, including
excessive daytime sleepiness, loud snoring during
sleep, refractory hypertension, and impaired quality of
life.
• Studies have also shown that OSA is associated with a
high risk for traffic accidents and cardiovascular
disease.

• It is estimated that nearly 80% of men and 93% of women
with moderate to severe sleep apnea are undiagnosed.
• Undiagnosed OSA may pose a variety of problems for
anesthesiologists. A number of case reports have
documented an increase in the incidence of postoperative
complications and deaths among patients suspected of
having OSA.
• Untreated OSA patients are known to have a higher
incidence of difficult intubation, postoperative
complications, increased intensive care unit admissions,
and greater duration of hospital stay.
• Identifying patients with OSA is the first step in preventing
postoperative complications due to OSA

• Studies have documented an increased incidence of coronary artery diseases,
hypertension, cerebrovascular accidents, gastroesophageal reflux disease,
congestive heart failure, and myocardial infarction in OSA patients.
• It is estimated that the average life span of an untreated OSA patient is 58 yr,
which is 20 yr shorter than the average life span of the general population
(men, 79 yr; women, 83 yr).
• OSA is also associated with an increased incidence of postoperative adverse
events. Undiagnosed OSA in surgical patients have a serious impact on the
postoperative outcome.
• Identifying patients with a high risk of OSA is the first step for the prevention
of adverse health events, adverse perioperative outcomes, and its treatment.
Screening tools work as a filter to separate the patients with a high risk of OSA
from the patients with a low risk of OSA. A good screening tool should be
validated in the target population against an accepted standard. It should be
easy to use and have a high sensitivity and acceptable specificity.

Perioperative Pulmonary Outcomes in Patients with
Sleep Apnea After Noncardiac Surgery.Stavros Memtsoudis S., Liu SS, Ma Y, Chiu
YC,Walz JM, Gaber-Baylis LK, Mazumdar M.Anesth Analg 2011;112:113–21
• population-based sample from National Inpatient Sample 2,610,441 entries for orthopedic and 3,441,262 for general
surgical procedures performed between 1998 and 2007dOrthopedic and general surgical procedures ;discharges with a
diagnosis code for SA were identified.
• Patients with the diagnosis of SA were matched to those without the disease based on demographic variables using the
propensity scoring method.
• Aspiration pneumonia, adult respiratory distress syndrome (ARDS), pulmonary embolism (PE),and the need for
intubation and mechanical ventilation were the primary outcomes.
• Odds ratio (OR) and absolute risk reduction along with 95% confidence interval were reported.
• . 2.52% and 1.40%, respectively, carried a diagnosis of SA.
• Patients with SA developed pulmonary complications more frequently than their matched controls after both
orthopedic and general surgical procedures, respectively :
• aspiration pneumonia: 1.18% vs 0.84% and 2.79% vs 2.05%;
• ARDS: 1.06% vs 0.45% and 3.79% vs 2.44%;
• intubation/mechanical ventilation: 3.99% vs 0.79% and 10.8% vs 5.94%,
• PE was more frequent in SA patients after orthopedic procedures (0.51% vs 0.42%, P 0.0038) but not after general
surgical procedures (0.45% vs 0.49%, P 0.22).
• SA was associated with a significantly higher adjusted OR of developing pulmonary complications after both orthopedic
and general surgical procedures, respectively,with the exception of PE (OR for aspiration pneumonia: 1.41 [1.35, 1.47]
and 1.37 [1.33, 1.41];for ARDS: 2.39 [2.28, 2.51] and 1.58 [1.54, 1.62]; for PE: OR 1.22 [1.15, 1.29] and 0.90 [0.84,0.97];
for intubation/mechanical ventilation: 5.20 [5.05, 5.37] and 1.95 [1.91, 1.98]).
• CONCLUSION: SA is an independent risk factor for perioperative pulmonary complications.

• National Inpatient sample:> 6.000.000
patients ,1998-2007.
• Aspiration pneumonia, adult respiratory
distress syndrome (ARDS), pulmonary
embolism (PE), the need for intubation and
mechanical ventilation were the primary
outcomes

Sleep apnea
Perioperative Pulmonary Outcomes in Patients with Sleep Apnea After Noncardiac Surgery.StavrosMemtsoudis S., Liu SS, Ma Y, Chiu
• OSA prevalence:2,41% in orthopedics,1,5 in general
surgery and increasing.

Conclusion on the relationship between sleep apnea and
pulmonary complications
• SA is an independent risk factor for perioperative pulmonary complications
• SA increased the OR for the need of perioperative tracheal intubation and
mechanical ventilation by 5-fold after orthopedic surgery and doubled the
odds after general surgical procedures.
• These findings are important because they provide evidence that
patients with SA are indeed at increased risk of perioperative
complications, thus supporting efforts targeted to more
intensively monitor this population and develop strategies to
prevent adverse events.
• the incidence of these adverse events is relevant insofar as they
are frequent enough to be associated with significant demand for
resources.

Incidence of sleep apnea:
•3.2% in general surgery
– Fidan H, Fidan F, Unlu M, Ela Y, Ibis A, Tetik L. Prevalence of sleep apnoea
in patients undergoing operation. Sleep Breath2006;10:161–5
• 4.2%;elective surgery
– Chung F, Ward B, Ho J, Yuan H, Kayumov L, Shapiro C.
• Pre-operative identification of sleep apnea risk in elective
surgical patients, using the Berlin questionnaire. J Clin
Anesth 2007;19:130–4 9.
•Sleep apnea is present in 70% of
obese patients

SA patients are at risk for ARDS???
• increased risk of aspiration + proinflammatory changes??
– proinflammatory changes have been described in patients with SA.
• link between SA and increased levels of C-reactive protein,
leukocyte superoxide, and soluble adhesion molecules.
Mayer K, Seeger W, Grimminger F. Enhanced release of superoxide from
polymorphonuclear neutrophils in obstructive sleep apnea. Am J Respir Crit Care Med
2000;162:566–70
• Shamsuzzaman AS, Winnicki M, Lanfranchi P, Wolk R, Kara T,Accurso V, Somers VK. Elevated
C-reactive protein in patients with obstructive sleep apnea. Circulation 2002;105:2462–4
Dyngovskaya L, Lavie P, Lavie L. Increased adhesion molecules expression and production of reactive oxygen species in
leukocytes of sleep apnea patients. Am J Respir Crit Care Med.2001;165:859–60
– In this context, there is experimental evidence in models of
repetitive hypoxemia/ regeneration that mimic SA suggesting an
upregulation of the proinflammatory transcription factor NF-B
(nuclear factor -light chain-enhancer of activated B cells) and
consequently several proinflammatory genes.47,48

SA patients use ICU more frequently
• + need of intubation and mechanical
ventilation
• +airway instrumentation
• +abnormal oropharyngeal anatomy that may
lead clinicians to err on the side of caution
when deciding to extubate patients’ tracheas
immediately after surgery

(SIMPLE) IDENTIFICATION OF
SLEEP APNEA PATIENTS

S.T.O.P.:snore,tired,observed(stopped
breathing),pressure
Frances Chung, Balaji Yegneswaran, Pu Liao, Sharon A. Chung, Santhira Vairavanathan, Sazzadul Islam, Ali Khajehdehi, Colin M.
Shapiro, STOP Questionnaire.#A Tool to Screen Patients for Obstructive Sleep Apnea .Anesthesiology 2008; 108:812–21
• S—“Do you snore loudly (louder than talking or
loud enough to be heard through closed
doors)?”
• T—“Do you often feel tired, fatigued, or
sleepy during daytime?”
• O—“Has anyone observed you stop breathing
during your sleep?
• ” P—“Do you have or are you being treated for
high blood pressure?

Stop tradotto:quasi corrisponde
• S—“Do you snore loudly (louder than talking or loud enough to be
heard through closed doors)?”Russi forte,+ che parlare a voce alta
tanto da essere udito a porta chiusa?Sornacchiare
• T—“Do you often feel tired, fatigued, or sleepy during daytime?”ti
senti stanco,affaticato o sonnolento durante il giorno?
Tirato……..
• O—“Has anyone observed you stop breathing during your
sleep?Nessuno ti ha osservato fermare il respiro durante il
sonno?osservato
• ” P—“Do you have or are you being treated for high blood pressure?
Hai o sei stato in terapia per ipertensione?Pressione

clinical diagnosis of OSA
• The clinical diagnosis of OSA was defined as
AHI(apnea /hypopnea) greater than 5 with
fragmented sleep and daytime sleepiness.
• According to the American Academy of Sleep
Medicine practice guideline:
• the severity of OSA is determined by the AHI:
• 5–15: mild;
• > 15–30: moderate;
• >30: severe.

Stop Bang
Frances Chung, Balaji Yegneswaran, Pu Liao, Sharon A. Chung, Santhira Vairavanathan, Sazzadul Islam, Ali
Khajehdehi, Colin M. Shapiro, STOP Questionnaire.#A Tool to Screen Patients for Obstructive Sleep Apnea
.Anesthesiology 2008; 108:812–21
• incorporating BMI, age, neck circumference,
and gender into the STOP scoring (STOP-Bang),
the sensitivity and NPV significantly
increased. They were both more than 90% for
the patients with moderate and severe OSA.

• STOP Questionnaire
• Height _____ inches/cm
• Weight _____ lb/kg
• BMI _____
• Age _____
• Neck circumference* _____ cm
• Gender:Male/Female
• Collar size of shirt: S, M, L, XL, or _____
inches/cm
BANG

Stop
• 1. Snoring
• Do you snore loudly (louder than talking or loud enough to be
heard through closed doors)?Yes No
• 2. Tired Do you often feel tired, fatigued, or sleepy during
daytime? Yes No
• 3. Observed Has anyone observed you stop breathing during
your sleep? Yes No
• 4. Blood pressure Do you have or are you being treated for
high blood pressure? Yes No
• * Neck circumference is measured by staff.
• High risk of OSA: answering yes to two or more questions
• Low risk of OSA: answering yes to less than two questions

Appendix 2: STOP-Bang Scoring
Model
• 1. Snoring Do you snore loudly (louder than talking or loud enough to be
heard through c losed doors)? Yes No
• 2. Tired Do you often feel tired, fatigued, or sleepy during daytime? Yes
No
• 3. Observed Has anyone observed you stop breathing during your sleep?
Yes No
• 4. Blood pressure Do you have or are you being treated for high blood
pressure? Yes No
• 5. BMI BMI more than 35 kg/m2? Yes No
• 6. Age Age over 50 yr old? Yes No
• 7. Neck circumference Neck circumference greater than 40 cm? Yes No
• 8. Gender Gender male? Yes No
• High risk of OSA: answering yes to three or more items
• Low risk of OSA: answering yes to less than three items

Blood pressure of OSAS patients
• Hypertens Res. 2009 Jun;32(6):428-32.
• Obstructive sleep apnea syndrome and hypertension: ambulatory blood pressure.
• Kario K.
• Source
• Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University School of Medicine,
Yakushiji, Shimotsuke, Tochigi, Japan. kkario@jichi.ac.jp
• Abstract
• Obstructive sleep apnea syndrome (OSAS) is an independent risk factor for hypertension and cardiovascular
disease. OSAS is the frequent underlying disease of secondary hypertension and resistant hypertension. OSAS
increases both daytime and night-time ambulatory blood pressures through the activation of various
neurohumoral factors including the sympathetic nervous system and the renin-angiotensin-aldosterone system. In
particular, OSAS predominantly increases ambulatory BP during sleep compared with the awake period, with the
result that OSAS is likely to be associated with the non-dipping pattern (diminished nocturnal BP fall) or riser
pattern (higher sleep BP than awake BP) of nocturnal BP. An additional characteristic of ABP in OSAS is increased
BP variability. The newly developed non-invasive hypoxia-trigger BP-monitoring system detected marked midnight
BP surges (ranging from around 10 to 100 mm Hg) during sleep in OSAS patients. The exaggerated BP surge may
trigger OSAS-related cardiovascular events occurring during sleep. Clinically, as nocturnal hypoxia is the
determinant of morning minus evening BP difference (ME difference), OSAS should be strongly suspected when
morning BP cannot be controlled <135/85 mm Hg with increased ME difference even by the specific
antihypertensive medications targeting morning hypertension such as bedtime dosing of antihypertensive drugs.
Understanding the characteristics of OSAS-related hypertension is essentially important to achieve perfect BP
control over a 24-h period, including the sleep period, for more effective prevention of cardiovascular disease.
• BP higher during sleep
• BP variability ++

Chung F, Yegneswaran B, Liao P, Chung SA, Vairavanathan S,
Islam S, Khajehdehi A, Shapiro CM. Validation of the Berlin questionnaire and
American Society of Anesthesiologists checklist as screening tools for
obstructive sleep apnea in surgical patients. Anesthesiology 2008;108:822–30
• Abstract
• BACKGROUND:
• Because of the high prevalence of obstructive sleep apnea (OSA) and its adverse impact on perioperative
outcome, a practical screening tool for surgical patients is required. This study was conducted to validate the
Berlin questionnaire and the American Society of Anesthesiologists (ASA) checklist in surgical patients and to
compare them with the STOP questionnaire.
• METHODS:
• After hospital ethics approval, preoperative patients aged 18 yr or older and without previously diagnosed OSA
were recruited. The scores from the Berlin questionnaire, ASA checklist, and STOP questionnaire were evaluated
versus the apnea-hypopnea index from in-laboratory polysomnography. The perioperative data were collected
through chart review.
• RESULTS:
• Of 2,467 screened patients, 33, 27, and 28% were respectively classified as being at high risk of OSA by the Berlin
questionnaire, ASA checklist, and STOP questionnaire. The performance of the screening tools was evaluated in
177 patients who underwent polysomnography. The sensitivities of the Berlin questionnaire, ASA checklist, and
STOP questionnaire were 68.9-87.2, 72.1-87.2, and 65.6-79.5% at different apnea-hypopnea index cutoffs. There
was no significant difference between the three screening tools in the predictive parameters. The patients with an
apnea-hypopnea index greater than 5 and the patients identified as being at high risk of OSA by the STOP
questionnaire or ASA checklist had a significantly increased incidence of postoperative complications.
• CONCLUSIONS:
• Similar to the STOP questionnaire, the Berlin questionnaire and ASA checklist demonstrated a moderately high
level of sensitivity for OSA screening. The STOP questionnaire and the ASA checklist were able to identify the
patients who were likely to develop postoperative complications.
• Comment in
• Anesthesiology. 2009 Jan;110(1):194; author reply 195.

• The Berlin questionnaire is a widely used screening tool for
OSA.
• It was an outcome of the Conference on Sleep in Primary
Care in April 1996 in Berlin, Germany.
• It includes 11 questions organized into the three categories,5
questions related to snoring and the cessation of breathing in
category 1, 4 questions related to daytime sleepiness in
category 2, 1 question about high blood pressure, and 1
question regarding BMI in category 3.
• When two of three categories are classified as positive for a
patient, the patient is rated as being at high risk of having
OSA

Berlin Questionnaire
•
• Height _____ m Weight _____ kg Age_____ Male/Female
• Please choose the correct response to each question.
• Category 1
• 1. Do you snore?
• a. Yes
• b. No
• c. Don’t know
• If you snore:
• 2. Your snoring is:
• a. Slightly louder than breathing
• b. As loud as talking
• c. Louder than talking
• d. Very loud—can be heard in adjacent rooms
• 3. How often do you snore?
• a. Nearly every day
• b. 3–4 times a week
• c. 1–2 times a week
• d. 1–2 times a month
• e. Never or nearly never
• 4. Has your snoring ever bothered other people?
• a. Yes
• b. No
• c. Don’t know
• 5. Has anyone noticed that you quit breathing during your sleep?

Berlin Questionnaire
• Category 2
• 6. How often do you feel tired or fatigued after your sleep?
• 7. During your waking time, do you feel tired, fatigued, or not up to par?
• 8. Have you ever nodded off or fallen asleep while driving a vehicle?
• a. Yes
• b. No
• If yes:
• 9. How often does this occur?
• Category 3
•
10. Do you have high blood pressure?
• a. Yes
• b. No
• c. Don’t kn

Scoring Berlin Questionnaire
• Adapted from table 2 in Netzer et al.7
• The questionnaire consists of three categories related to the risk of having OSA.
• Categories and scoring:
• Category 1: items 1, 2, 3, 4, and 5
• Item 1: If yes is the response, assign 1 point.
• Item 2: If c or d is the response, assign 1 point.
• Item 3: If a or b is the response, assign 1 point.
• Item 4: If a is the response, assign 1 point.
• Item 5: If a or b is the response, assign 2 points.
• Category 1 is positive if the total score is 2 or more points.
• Category 2: items 6, 7, and 8 (item 9 should be noted separately)
• Item 8: If a is the response, assign 1 point.
• Category 2 is positive if the total score is 2 or more points.
• Category 3 is positive if the answer to item 10 is yes or if the BMI
• of the patient is greater than 30 kg/m2.
• High risk of OSA: two or more categories scored as positive
• Low risk of OSA: only one or no category scored as positive

ASA Checklist
Gross JB, Bachenberg KL, Benumof JL, Caplan RA, Connis RT, Cote CJ,
Nickinovich DG, Prachand V, Ward DS, Weaver EM, Ydens L, Yu S: Practice guidelines for the perioperative management of patients
with obstructive sleep apnea: A report by the American Society of Anesthesiologists Task Force on PerioperativeManagement of
Patients with Obstructive Sleep Apnea. ANESTHESIOLOGY
2006; 104:1081–93
• Category 1: Predisposing Physical Characteristics
• a. BMI 35 kg/m2
• b. Neck circumference 43 cm/17 inches (men) or 40 cm/16 inches
• (women)
• c. Craniofacial abnormalities affecting the airway
• d. Anatomical nasal obstruction
• e. Tonsils nearly touching or touching the midline
• Category 2: History of Apparent Airway Obstruction during Sleep
• Two or more of the following are present (if patient lives alone or sleep is not observed by another person,
then only one of the following need be present):
• a. Snoring (loud enough to be heard through closed door)
• b. Frequent snoring
• c. Observed pauses in breathing during sleep
• d. Awakens from sleep with choking sensation
• e. Frequent arousals from sleep

ASA Checklist ;part 2
• Category 3: Somnolence
• One or more of the following are present:
• a. Frequent somnolence or fatigue despite adequate “sleep”
• b. Falls asleep easily in a nonstimulating environment (e.g., watching
• TV, reading, riding in or driving a car) despite adequate “sleep”
• c. [Parent or teacher comments that child appears sleepy during the
• day, is easily distracted, is overly aggressive, or has difficulty concentrating]*
• d. [Child often difficult to arouse at usual awakening time]*
• Scoring:
• If two or more items in category 1 are positive, category 1 is positive.
• If two or more items in category 2 are positive, category 2 is positive.
• If one or more items in category 3 are positive, category 3 is positive.
• High risk of OSA: two or more categories scored as positive
• Low risk of OSA: only one or no category scored as positive
• * Items in brackets refer to pediatric patients.

Chung F, Yegneswaran B, Liao P, Chung SA, Vairavanathan S,
Islam S, Khajehdehi A, Shapiro CM. Validation of the Berlin questionnaire and
American Society of Anesthesiologists checklist as screening tools for obstructive sleep
apnea in surgical patients. Anesthesiology 2008;108:822–30
• Our data suggest that the patients identified
as being at high risk of having OSA by the
STOP questionnaire or by the ASA checklist
had an increased postoperative complication
rate(mainly desaturation ).

IMPORTANT ANATOMICAL
CONSIDERATIONS FOR OSA
PATIENTS

FIN QUI :METTERE INSIEME LE
CARATTERISTICHE ANATOMICHE DELLE
OSA

OSA e anatomia cranio facciale e vie
aeree:1
• strong determinants for tongue volume :the
midface width,lower-face width , Surface facial
dimensions in combination
– Sleep. 2010 Sep;33(9):1249-54.
Relationship between surface facial dimensions and upper airway
structures in obstructive sleep apnea.Lee RW, Sutherland K, Chan
AS, Zeng B, Grunstein RR, Darendeliler MA, Schwab RJ, Cistulli PA.
• Airway Length had a positive correlation and the
lateral/retroglossal anteroposterior dimension
ratio an inverse correlation with the Resp
disturbance
• J Oral Maxillofac Surg. 2010 Feb;68(2):354-62. Epub 2010 Jan 15.Three-dimensional computed
tomographic analysis of airway anatomy in patients with obstructive sleep apnea.Abramson Z, Susarla
S, August M, Troulis M, Kaban L.

OSA e anatomia cranio facciale e vie
aeree:2
• 1) the VP was smaller in apnoeic patients, only during part of the respiratory cycle; 2) the variation in VP area
during the respiratory cycle was greater in apnoeic patients than in controls, particularly during sleep, suggesting
an increased compliance of the VP in these patients; 3) VP narrowing was similar in the lateral and anterior-posterior
dimensions, both in controls and apnoeic patients while awake; apnoeic patients during sleep have a
more circular VP upon reaching the minimum area; 4) there was an inverse relationship between dimensions of
the lateral pharyngeal walls and airway area, probably indicating that lateral walls are passively compressed or
stretched as a result of changes in the airway calibre; and 5) soft palate and parapharyngeal fatpads were larger in
apnoeic patients, although their role in the genesis of OSA is uncertain. It was concluded that changes in the
velopharynx area and diameter during the respiratory cycle are greater in apnoeic patients than in normal
subjects, particularly during sleep.
– Eur Respir J. 2001 Jan;17(1):79-86.
Magnetic resonance imaging of the pharynx in OSA patients and healthy subjects.Ciscar MA, Juan G, Martínez V, Ramón M,
Lloret T, Mínguez J, ArmengotM, Marín J, Basterra J.
• mean values of both the cross-sectional area and the anterior-posterior diameter at the soft
palate were significantly reduced by spontaneous sleep in the OSAS.
– Ann Otol Rhinol Laryngol. 2001 Feb;110(2):183-9.Quantitative assessment of the pharyngeal airway by dynamic
magnetic resonance imaging in obstructive sleep apnea syndrome.Ikeda K, Ogura M, Oshima T, Suzuki H, Higano S,
Takahashi S, Kurosawa H, HidaW, Matsuoka H, Takasaka T.

J Oral Maxillofac Surg. 2011 Mar;69(3):663-76.
Maxillary, mandibular, and chin advancement: treatment planning based on
airway anatomy in obstructive sleep apnea.
Schendel S, Powell N, Jacobson R.
• Source
• Stanford University, Palo Alto, CA, USA. sschendel@stanford.edu
• Erratum in
• J Oral Maxillofac Surg. 2011 Aug;69(8);2077.
• Abstract
• Surgical correction of obstructive sleep apnea (OSA) syndrome involves understanding a number of
parameters, of which the 3-dimensional airway anatomy is important. Visualization of the upper
airway based on cone beam computed tomography scans and automated computer analysis is an
aid in understanding normal and abnormal airway conditions and their response to surgery. The
goal of surgical treatment of OSA syndrome is to enlarge the velo-oropharyngeal airway by
anterior/lateral displacement of the soft tissues and musculature by maxillary, mandibular, and
possibly, genioglossus advancement. Knowledge of the specific airway obstruction and
characteristics based on 3-dimensional studies permits a directed surgical treatment plan that can
successfully address the area or areas of airway obstruction. The end occlusal result can be
improved when orthodontic treatment is combined with the surgical plan. The individual with OSA,
though, is more complicated than the usual orthognathic patient, and both the medical condition
and treatment length need to be judiciously managed when OSA and associated conditions are
present. The perioperative management of the patient with OSA is more complex and the margin
for error is reduced, and this needs to be taken into consideration and the care altered as indicated.

J Oral Maxillofac Surg. 2010 Feb;68(2):354-62. Epub 2010 Jan 15.
Three-dimensional computed tomographic analysis of airway anatomy in patients
with obstructive sleep apnea.
Abramson Z, Susarla S, August M, Troulis M, Kaban
• L.
• Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital, Harvard School of Dental Medicine, Boston, MA, USA.
• Abstract
• PURPOSE:
• To identify abnormalities in airway size and shape that correlate with the presence and severity of obstructive sleep apnea (OSA).
• MATERIALS AND METHODS:
• This was a retrospective case series of patients undergoing treatment of OSA who had preoperative computed tomographic (CT) scans of the upper
airway available. Patients who had undergone CT scanning for nonairway pathologic features during the same period served as the controls. Digital
3D-CT reconstructions were made and 12 parameters of airway size and 4 of shape were analyzed. The posterior airway space, middle airway space,
and hyoid to mandibular plane distance were measured on the lateral cephalograms of the patients with OSA. Bivariate analysis was used to identify
the factors associated with the presence and severity of OSA as measured by the respiratory disturbance index (RDI). Multiple regression analysis
identified the factors that correlated with the RDI.
• RESULTS:
• Of the 44 patients with OSA, 15 (10 men and 5 women) had pre- and postoperative CT scans available. In addition, 17 patients (11men and 6
women) were used as controls. The airway length was significantly increased in the patients with OSA (P < .01). On bivariate
analysis, the length, lateral/retroglossal anteroposterior dimension ratio and genial tubercle to hyoid bone distance were
associated with the RDI (P < .03). On multiple regression analysis, length (P < .01) had a positive correlation and the
lateral/retroglossal anteroposterior dimension ratio (P = .04) an inverse correlation with the RDI.
• CONCLUSIONS:
• The results of this study indicate that the presence of OSA is associated with an increase in airway length. Airways that were more elliptical in shape
and mediolaterally oriented (greater lateral/retroglossal anteroposterior dimension ratio) had a decreased tendency toward obstruction.

Sleep. 2010 Sep;33(9):1249-54.
Relationship between surface facial dimensions and upper airway structures in
obstructive sleep apnea.Lee RW, Sutherland K, Chan AS, Zeng B, Grunstein RR,
Darendeliler MA, Schwab RJ, Cistulli PA.
• Centre for Sleep Health and Research, Department of Respiratory Medicine, Royal North Shore Hospital St Leonards, NSW Australia.
• Abstract
• STUDY OBJECTIVES:
• We hypothesized that the facial phenotype is closely linked to upper airway anatomy. The aim of this study was
to investigate the relationship between surface facial dimensions and upper airway structures using magnetic resonance imaging (MRI) in subjects
with obstructive sleep apnea (OSA).
• DESIGN:
• Cohort study.
• SETTING:
• Sleep investigation unit.
• PATIENTS:
• Sixty-nine patients (apnea-hypopnea index > or = 10/h) underwent MRI as part of a study of upper airway anatomy in oral appliance therapy.
• INTERVENTIONS:
• Measurements of a range of surface facial dimensions and upper airway soft tissue volumes were performed on the MR images using image-analysis
software. Pearson correlation analyses were performed.
• MEASUREMENTS AND RESULTS:
• Significant correlations were identified between a number of surface facial dimensions and neck circumference. Significant positive correlations were
demonstrated between surface facial dimensions (including facial widths, facial heights, nose width, interocular and intercanthal widths) and upper
airway structures. The strongest associations were between the tongue volume and the midface width (r = 0.70, P < 0.001), and lower-face width (r =
0.60, P <0.001). Surface facial dimensions in combination were also strong determinants for tongue volume (r2 = 0.69). Correlations between surface
soft tissue thickness and upper airway soft tissue volumes occurred at the level of the midface but not at the level of the lower face.
• CONCLUSIONS:
• This study demonstrates that there is a relationship between surface facial dimensions and upper airway structures in subjects with OSA. These
findings support the potential role of surface facial measurements in anatomic phenotyping for OSA

• World J Gastroenterol. 2010 Sep 14;16(34):4243-52.
• Obstructive sleep apnea syndrome and fatty liver: association or causal
link?
• Ahmed MH, Byrne CD.
• Abstract
• Obstructive sleep apnea (OSA) is a complex disorder that consists of upper
airway obstruction, chronic intermittent hypoxia and sleep fragmentation.
OSA is well known to be associated with hypoxia, insulin resistance and
glucose intolerance, and these factors can occur in the presence or
absence of obesity and metabolic syndrome. Although it is well
established that insulin resistance, glucose intolerance and obesity occur
frequently with non-alcoholic fatty liver disease (NAFLD), it is now
becoming apparent that hypoxia might also be important in the
development of NAFLD, and it is recognized that there is increased risk of
NAFLD with OSA. This review discusses the association between OSA,
NAFLD and cardiovascular disease, and describes the potential role of
hypoxia in the development of NAFLD with OSA.

È un lavoro interessantissimo!!!!quali
sono le ricadute farmacologiche ???
• Am J Respir Crit Care Med. 2010 Nov 15;182(10):1321-9. Epub 2010 Jul 9.
• Chronic intermittent hypoxia alters density of aminergic terminals and receptors in the hypoglossal motor nucleus.
• Rukhadze I, Fenik VB, Benincasa KE, Price A, Kubin L.
• Source
• Department of Animal Biology, University of Pennsylvania, Philadelphia, 19104-6046, USA. rukhadze@vet.upenn.edu
• Abstract
• RATIONALE:
• Patients with obstructive sleep apnea (OSA) adapt to the anatomical vulnerability of their upper airway by generating increased activity in upper
airway-dilating muscles during wakefulness. Norepinephrine (NE) and serotonin (5-HT) mediate, through α₁-adrenergic and 5-HT₂A receptors, a wake-related
excitatory drive to upper airway motoneurons. In patients with OSA, this drive is necessary to maintain their upper airway open. We tested
whether chronic intermittent hypoxia (CIH), a major pathogenic factor of OSA, affects aminergic innervation of XII motoneurons that innervate
tongue-protruding muscles in a manner that could alter their airway-dilatory action.
• OBJECTIVES:
• To determine the impact of CIH on neurochemical markers of NE and 5-HT innervation of the XII nucleus.
• METHODS:
• NE and 5-HT terminal varicosities and α₁-adrenergic and 5-HT₂A receptors were immunohistochemically visualized and quantified in the XII nucleus in
adult rats exposed to CIH or room air exchanges for 10 h/d for 34 to 40 days.
• MEASUREMENTS AND MAIN RESULTS:
• CIH-exposed rats had approximately 40% higher density of NE terminals and approximately 20% higher density of 5-HT terminals in the ventromedial
quadrant of the XII nucleus, the region that controls tongue protruder muscles, than sham-treated rats. XII motoneurons expressing α₁-
adrenoceptors were also approximately 10% more numerous in CIH rats, whereas 5-HT₂A receptor density tended to be lower in CIH rats.
• CONCLUSIONS:
• CIH-elicited increase of NE and 5-HT terminal density and increased expression of α₁-adrenoceptors in the XII nucleus may lead to augmentation of
endogenous aminergic excitatory drives to XII motoneurons, thereby contributing to the increased upper airway motor tone in patients with OSA.

• Sleep Med. 2010 Jun;11(6):540-4. Epub 2010 May 13.
• MRI of the pharynx in ischemic stroke patients with and without obstructive sleep apnea.
• Brown DL, Bapuraj JR, Mukherji SK, Chervin RD, Concannon M, Helman JI, Lisabeth LD.
• Source
• Stroke Program, University of Michigan Medical School, The Cardiovascular Center - Stroke Program, 1500 E. Medical Center Drive - SPC#5855, Ann
Arbor, MI 48109-5855, USA. devinb@umich.edu
• Abstract
• BACKGROUND:
• Obstructive sleep apnea (OSA) is common after stroke and associated with poor stroke outcomes. Whether OSA after acute stroke is caused by
anatomic, physiologic, or both etiologies has not been studied. We therefore used brain magnetic resonance imaging (MRI) scans to assess
oropharyngeal anatomy in stroke patients with and without OSA.
• METHODS:
• Patients within 7 days of ischemic stroke underwent nocturnal polysomnography. Sagittal T1-weighted MRI performed for clinical purposes was used
to measure retropalatal distance, soft palatal length, soft palatal thickness, retroglossal space, and tongue length. Nasopharyngeal area and high
retropharyngeal area were measured from axial T2-weighted images, and lateral pharyngeal wall thickness from coronal T1-weighted images.
• RESULTS:
• Among 27 subjects, 18 (67%) had OSA (apnea/hypopnea index (AHI)5). Demographics, vascular risk factors, and stroke severity were similar in the
two groups. Median retropalatal distance was shorter in subjects with OSA (Wilcoxon rank-sum test, p=0.03). Shorter retropalatal distance was
associated with higher AHI (linear regression, p=0.04). None of the other morphological characteristics differed.
• CONCLUSIONS:
• Anatomic difference between awake acute stroke patients with and without OSA shows that the sleep disorder cannot be attributed solely to sleep,
sleeping position, or changes in neuromuscular control that are specific to the sleep state.

Eur Respir J. 2001 Jan;17(1):79-86.
Magnetic resonance imaging of the pharynx in OSA patients and healthy
subjects.Ciscar MA, Juan G, Martínez V, Ramón M, Lloret T, Mínguez J,
Armengot M, Marín J, Basterra J.
• Source
• Service of Pneumology, Hospital General Universitario de Valencia, Spain.
• Abstract
• Obstructive sleep apnoea (OSA) occurs because of recurrent narrowing and occlusion of the
velopharynx (VP) during sleep. The specific cause of OSA is unknown. Cephalometric radiography,
fibreoptic nasopharyngoscopy, acoustic reflection techniques, and computerized tomography have
limitations (dynamic and tridimensional evaluation) in the mechanism of occlusion investigation.
Static and dynamic examination of the soft tissue structures surrounding the upper airway during
the respiratory cycle in wakefulness and sleep, can lead to a better understanding of the process.
Ultrafast magnetic resonance imaging (one image per 0.8 s) was used to study the upper airway
and surrounding soft tissue in 17 patients with OSA during wakefulness and sleep, and in eight
healthy subjects whilst awake. The major findings of this investigation in the 25 subjects were as
follows: 1) the VP was smaller in apnoeic patients, only during part of the respiratory cycle; 2) the
variation in VP area during the respiratory cycle was greater in apnoeic patients than in controls,
particularly during sleep, suggesting an increased compliance of the VP in these patients; 3) VP
narrowing was similar in the lateral and anterior-posterior dimensions, both in controls and apnoeic
patients while awake; apnoeic patients during sleep have a more circular VP upon reaching the
minimum area; 4) there was an inverse relationship between dimensions of the lateral pharyngeal
walls and airway area, probably indicating that lateral walls are passively compressed or stretched
as a result of changes in the airway calibre; and 5) soft palate and parapharyngeal fatpads were
larger in apnoeic patients, although their role in the genesis of OSA is uncertain. It was concluded
that changes in the velopharynx area and diameter during the respiratory cycle are greater in
apnoeic patients than in normal subjects, particularly during sleep. This

Ann Otol Rhinol Laryngol. 2001 Feb;110(2):183-9.
Quantitative assessment of the pharyngeal airway by dynamic magnetic resonance
imaging in obstructive sleep apnea syndrome.
Ikeda K, Ogura M, Oshima T, Suzuki H, Higano S, Takahashi S, Kurosawa H, Hida W,
Matsuoka H, Takasaka T.
• Source
• Department of Otorhinolaryngology, Tohoku University School of Medicine, Sendai, Japan.
• Abstract
• Dynamic changes in the pharyngeal airway of patients with obstructive sleep apnea syndrome
(OSAS) were evaluated by quantitating the findings of real-time imaging performed during
wakefulness and spontaneous sleep by means of dynamic magnetic resonance imaging (MRI). Six
patients with OSAS and 3 non-OSAS subjects, selected prospectively and randomly, underwent
polysomnography and dynamic MRI. The cross-sectional areas of the soft palate and oropharynx
and the anterior-posterior airway dimensions seen during wakefulness and spontaneous sleep were
calculated by US National Institutes of Health imaging software. On the basis of a case control
study, comparisons were made with age-matched and body mass index-matched obese non-OSAS
snorers. Spontaneous sleep caused significant obstruction and narrowing of various sites of the
pharyngeal airway in the OSAS patients, but not in the non-OSAS subjects. During wakefulness, the
non-OSAS subjects showed no marked narrowing of the pharyngeal airways, whereas a transient
but significant narrowing was observed in the OSAS patients. The mean values of both the cross-sectional
area and the anterior-posterior diameter at the soft palate were significantly reduced by
spontaneous sleep in the OSAS patients. Dynamic MRI in awake OSAS patients shows promise as a
routine diagnostic tool for localizing the upper airway collapse for appropriate selection of surgical
therapy.

Fin qui;diapo seguenti da far vedere …

Normal patient,max (A)and minimum(B) area

Max(a) and minimum(B) area of a normal patient awake in
apnea

Max(A) and minimum(B) area of a sleeping apneic patient,normal

Pharyngeal shape and dimensions in healthy subjects, snorers,
and patients with obstructive sleep apnoea.
Rodenstein DO, Dooms G, Thomas Y, Liistro G, Stanescu DC,
Culée C, Aubert-Tulkens G.
• Source
• Pulmonary Division, Universitaires St Luc, Brussels, Belgium.
• Abstract
• To characterise the relation between pharyngeal anatomy and sleep related disordered breathing,
17 men with complaints of snoring were studied by all night polysomnography. Ten of them had
obstructive sleep apnoea (mean (SD) apnoea-hypopnoea index 56.3 (41.7), age 52 (10) years, body
mass index 31.4 (5.3) kg/m2); whereas seven were simple snorers (apnoea-hypopnoea index 6.7
(4.6), age 40 (17) years, body mass index 25.9 (4.3) kg/m2). The pharynx was studied by magnetic
resonance imaging in all patients and in a group of eight healthy subjects (age 27 (6) years, body
mass index 21.8 (2.2) kg/m2, both significantly lower than in the patients; p less than 0.05). On the
midsagittal section and six transverse sections equally spaced between the nasopharynx and the
hypopharynx several anatomical measurements were performed. Results showed that there was no
difference between groups in most magnetic resonance imaging measurements, but that on
transverse sections the pharyngeal cross section had an elliptic shape with the long axis oriented in
the coronal plane in normal subjects, whereas in apnoeic and snoring patients the pharynx was
circular or had an elliptic shape but with the long axis oriented in the sagittal plane. It is suggested
that the change in pharyngeal cross sectional shape, secondary to a reduction in pharyngeal
transverse diameter, may be related to the risk of developing sleep related disordered breathing

• Eur Respir J. 1996 Sep;9(9):1801-9.
• Relationship between body mass index, age and upper airway measurements in snorers and sleep apnoea
patients.
• Mayer P, Pépin JL, Bettega G, Veale D, Ferretti G, Deschaux C, Lévy P.
• Source
• Dept of Respiratory Medicine, ANTADIR, Quebec, Canada.
• Abstract
• Anatomical pharyngeal and craniofacial abnormalities have been reported using upper airway imaging in snorers
with or without obstructive sleep apnoea (OSA). However, the influences of the age and weight of the patient on
these abnormalities remain to be established. The aim of this study was, therefore, to evaluate in a large
population of snorers with or without OSA, the relationship between body mass index (BMI), age and upper
airway morphology. One hundred and forty patients were referred for assessment of a possible sleep-related
breathing disorder and had complete polysomnography, cephalometry and upper airway computed tomography.
For the whole population, OSA patients had more upper airway abnormalities than snorers. When subdivided for
BMI and age, however, only lean or younger OSA patients were significantly different from snorers as regards their
upper airway anatomy. The shape of the oropharynx and hypopharynx changed significantly with BMI both in OSA
patients and snorers, being more spherical in the highest BMI group due mainly to a decrease in the transverse
axis. On the other hand, older patients (> 63 yrs), whether snorers or apnoeics, had larger upper airways at all
pharyngeal levels than the youngest group of patients (< 52 yrs). For the total group of patients, upper airway
variables explained 26% of the variance in apnoea/hypopnoea index (AHI), whereas in lean (BMI < 27 kg.m-2) or
youngest (age < 52 yrs) subjects upper airway variables explained, respectively 69 and 55% of the variance in AHI.
In conclusion, in lean or young subjects, upper airway abnormalities explain a major part of the variance in
apnoea/hypopnoea index and are likely to play an important physiopathogenic role. This study also suggests that
the shape of the pharyngeal lumen in awake subjects is more dependent on body mass index than on the
presence of obstructive sleep apnoea. Further investigation looking at upper airway imaging for surgical selection
in obstructive sleep apnoea should focus on lean and young patients

• Radiol Med. 2004 Sep;108(3):238-54.
• Magnetic resonance imaging in simple snoring and obstructive sleep apnea-hypopnea syndrome.
• [Article in English, Italian]
• Fusco G, Macina F, Macarini L, Garribba AP, Ettorre GC.
• Source
• Azienda USL BA/4, U.O. Radiologia, Ospedale Giovanni XXIII, Bari. fusco.giov@virgilio.it
• Abstract
• PURPOSE:
• Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS) is a condition characterised by periodic cessation of breathing during sleep, associated with
Upper Air-Digestive Ways (UADW) morphologic abnormalities that can be detected, in awake patients, by using various imaging techniques. The
purpose of this study is to determine the usefulness of MR imaging and new original morphometrical measurements that we are proposing in
patients with Sleep Obstructive Breathing Disordered (SOBD).
• We studied 70 patients (52 with OSAHS and 18 snoring without OSAHS) using 1.5T and 0.5T MR imagers with neck and head coils and T1-DP-T2-
weighted SE sequences. During the procedure, the patients were awake and with tidal breathing. We also evaluated sagittal pharyngeal diameters at
different levels; the length and maximum width of soft palate; the distance between the hyoid bone and the C2C3-Me line (ideally joining the
geometrical centre of the C2-C3 intervertebral space to the lower point of mandibular symphysis) measured on the perpendicular; the angle resulting
from the longitudinal axis of the cervical spine and the epiglottis axis (alpha); the slope angle of the tongue -- resulting from the longitudinal axis of
the cervical spine and the longitudinal axis of the tongue (beta). We used sagittal, coronal and axial sections of the head and neck.
• RESULTS:
• In OSAHS patients, pharynx calibre medium sizes were reduced compared with simple snoring patients. Only in OSAHS patients (not in simple snorers
without OSAHS) we observed: 16 patients with narrowing sites = or <3 mm. On axial images we observed three different narrowing patterns:
rounded, with greater anterior-posterior axis; with greater axis in lateral direction. In OSAHS patients we also observed, on average, increase of the
distance between the hyoid bone (Hmr point) and the line C2C3-Me; increase in the angle resulting between cervical rachis and epiglottis (alpha);
reduction of sloping angle of the tongue (beta).
• CONCLUSIONS:
• MR imaging, together with the morphometrical measurements we are proposing, is useful to evaluate UADW in SOBD. In particular, we noted that
increase of the distance between the hyoid bone (Hmr point) and the line C2C3-Me (due to lowering of the hyoid bone), increase in the angle
resulting between the cervical rachis and the epiglottis (alpha) and the reduction of the sloping angle of the tongue (beta), are highly specific and
sensitive indexes in OSAHS. There are different levels and findings of narrowing in OSAHS and their identification is very important for a surgical
approach: the uvulo-palato-pharyngoplasty (UPPP) has a higher success rate in patients with obstruction at retro-palatopharynx site, but it is
associated with no (or poor) results in hypopharyngeal obstruction.

• Lin Chung Er Bi Yan Hou Tou Jing Wai Ke Za Zhi. 2010 Dec;24(24):1108-11.
• [Study of Cine-MRI for the soft palate in patients with obstructive sleep apnea hypopnea syndrome].
• [Article in Chinese]
• Qian B, Tang G, Liu Y, Yao J.
• Source
• Department of Otolaryngology, the Tenth People's Hospital, Tongji University, Shanghai, 200072, China. szj961017@sina.com
• Abstract
• OBJECTIVE:
• To study dynamic change and pathophysiology of airway obstruction of the soft palate in patients with obstructive sleep apnea hypopnea syndrome
(OSAHS) during wakefulness and natural sleep.
• METHOD:
• Sixteen patients who were diagnosed as OSAHS by sleep questionnaires, medical examination and polysomnography were enrolled in this study in
Shanghai Tenth People' Hospital from May to December during 2007. All patients were requested to keep awake prior to examination. Sequential
midline sagittal images of the upper airway were obtained during awake and asleep state with Cine-MRI and been transmitted to portable computer.
Morphologic change of the soft palate, the anterior-posterior pendulum angle of the soft palate, the anteroposterior diameter and the length of soft
palate were measured. Statistical analysis was performed with paired t-test.
• RESULT:
• During wakefulness: soft palate caused obstruction by floating backwards and widening anteroposterior diameter(distance between hard palate and
uvula P > 0.05, included angle of hard palate and segmental vente of uvula P < 0.05, included angle of hard palate and segmental dorsum of uvula P <
0.01, difference of included angle P < 0.01). Main obstruction site was on retropalatal region. During natural sleep: soft palate caused obstruction by
lengthening down and widening anteroposterior diameter (distance between hard palate and uvula P < 0.01), included angle of hard palate and
segmental vente of uvula P > 0.05, included angle of hard palate and segmental dorsum of uvula P > 0.05, difference of included angle P < 0.01). Main
obstruction site was on retroglottal region.
• CONCLUSION:
• Morphologic change of soft palate in patients with OSAHS is multiple, and level of obstruction is deeper during natural sleep than during
wakefulness. Main reason of airway obstruction is distinct during different state. The obstruction of upper airway of patients with OSAHS during
wakefulness can't replace that during natural sleep.

• Zhonghua Kou Qiang Yi Xue Za Zhi. 2006 Apr;41(4):222-5.
• [Obstructive site of the upper airway in patients with obstructive sleep apnea hypopnea syndrome: analysis of dynamic MRI].
• [Article in Chinese]
• Hu RD, Zhang XH, Pan KF, Liu YH.
• Source
• Department of Orthodontics, Hospital of Stomatology, Wenzhou Medical College, Wenzhou Zhejiang 325027, China.
• Abstract
• OBJECTIVE:
• To investigate the obstructive site and the dynamic change of the upper airway in patients with obstructive sleep apnea hypopnea syndrome
(OSAHS) during sleep and wakefulness.
• METHODS:
• After being deprived of sleeping for 20 hours, sequential midline sagittal images of the upper airway were obtained in 21 patients during sleep and
wakefulness with dynamic MRI. The obstructive state was studied according to hypopnea (< 10 s) and apnea (> or = 10 s). The length of obstruction
site was measured and the dynamic characteristics of obstruction was observed. Statistical analysis was performed with paired t-test.
• RESULTS:
• The obstruction at the level of the palatopharynx in patients with hypopnea during wakefulness was similar to that in patients with apnea during
sleep. The maximal length [(6.61 +/- 1.23) cm], the minimal length [(0.95 +/- 0.22) cm] and maximal length difference [(5.66 +/- 1.27) cm] related to
apnea during sleep were longer than those correlated with hypopnea [(2.99 +/- 0.51) cm, (0.72 +/- 0.23) cm, (2.27 +/- 0.67) cm, respectively] in
wakefulness. (P < 0.01).
• CONCLUSIONS:
• The obstruction of upper airway during sleep is dynamic and multilevel in patients with OSAHS. To a certain degree, hypopnea during wakefulness
can give a clue to the obstructive state during sleep.

Arch Otolaryngol Head Neck Surg. 2009 Sep;135(9):910-4.
An investigation of upper airway changes associated with mandibular
advancement device using sleep videofluoroscopy in patients with
obstructive sleep apnea.
Lee CH, Kim JW, Lee HJ, Yun PY, Kim DY, Seo BS, Yoon IY, Mo JH.
• Source
• Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seoul National University College of
Medicine, Bundang-Gu, Seongnam, Korea.
• Abstract
• OBJECTIVE:
• To quantitatively evaluate the effects of the mandibular advancement device (MAD) on changes in the upper respiratory tract during sleep using
sleep videofluoroscopy (SVF) in patients with obstructive sleep apnea (OSA).
• DESIGN:
• Retrospective analysis.
• SETTING:
• Academic tertiary referral center.
• PATIENTS:
• Seventy-six patients (68 men and 8 women) who were treated with the MAD for OSA were included from September 1, 2005, through August 31,
2008.
• INTERVENTION:
• All patients underwent nocturnal polysomnography and SVF before and at least 3 months after receipt of the custom-made MAD. Sleep
videofluoroscopy was performed before and after sleep induction and was analyzed during 3 states of awakeness, normoxygenation sleep, and
desaturation sleep.
• MAIN OUTCOME MEASURES:
• Changes in the length of the soft palate, retropalatal space, retrolingual space, and angle of mouth opening were evaluated during sleep events with
or without the MAD.
• RESULTS:
• Without the MAD, the length of the soft palate and the angle of mouth opening increased during sleep events, especially in desaturation sleep,
compared with the awake state. The retropalatal space and retrolingual space became much narrower during sleep compared with the awake state.
The MAD had marked effects on the length of the soft palate, retropalatal space, retrolingual space, and angle of mouth opening. The retropalatal
space and retrolingual space were widened, and the length of the soft palate was decreased. The MAD kept the mouth closed.
• CONCLUSIONS:
• Sleep videofluoroscopy showed dynamic upper airway changes in patients with OSA, and the MAD exerted multiple effects on the size and
configuration of the airway. Sleep videofluoroscopy demonstrated the mechanism of action of the MAD in patients with OSA. The MAD increased the
retropalatal and retrolingual spaces and decreased the length of the soft palate and the angle of mouth opening, resulting in improvement of OSA.

• Am J Respir Crit Care Med. 1995 Nov;152(5 Pt 1):1673-89.
• Upper airway and soft tissue anatomy in normal subjects and patients with sleep-disordered breathing.
Significance of the lateral pharyngeal walls.
• Schwab RJ, Gupta KB, Gefter WB, Metzger LJ, Hoffman EA, Pack AI.
• Source
• Department of Medicine, University of Pennsylvania Medical Center, Philadelphia 19104-4283, USA.
• Abstract
• The geometry and caliber of the upper airway in apneic patients differs from those in normal subjects. The apneic
airway is smaller and is narrowed laterally. Examination of the soft tissue structures surrounding the upper airway
can lead to an understanding of these apneic airway dimensional changes. Magnetic resonance imaging was
utilized to study the upper airway and surrounding soft tissue structures in 21 normal subjects, 21 snorer/mild
apneic subjects, and 26 patients with obstructive sleep apnea. The major findings of this investigation in the 68
subjects were as follows: (1) minimum airway area was significantly smaller in apneic compared with normal
subjects and occurred in the retropalatal region; (2) airway narrowing in apneic patients was predominantly in the
lateral dimension; there was no significant difference in the anterior-posterior (AP) airway dimension between
subject groups; and (3) distance between the rami of the mandible was equal between subject groups, and thus
the narrowing of the lateral dimension was not explained by differences in bony structure; (4) lateral airway
narrowing was explained predominantly by larger pharyngeal walls in apneic patients (the parapharyngeal fat pads
were not closer together as one would expect if the airway walls were compressed by fat); and (5) fat pad size at
the level of the minimum airway was not greater in apneic than normal subjects. At the minimum airway area,
thickness of the lateral pharyngeal muscular walls rather than enlargement of the parapharyngeal fat pads was
the predominant anatomic factor causing airway narrowing in apneic subjects.

AJR Am J Roentgenol. 1993 Feb;160(2):311-4.
Evaluation of the pharyngeal airway in patients with sleep apnea: value of
ultrafast MR imaging.
Suto Y, Matsuo T, Kato T, Hori I, Inoue Y, Ogawa S, Suzuki T, Yamada M, Ohta Y.
• Source
• Department of Radiology, Tottori University Faculty of Medicine, Yonago, Japan.
• Abstract
• OBJECTIVE:
• Sleep apnea is often caused by obstruction of the pharyngeal airway. The goal of this study was to use ultrafast
MR imaging to examine the pharyngeal airway in patients with sleep apnea and to evaluate the usefulness of this
technique for localizing the site of obstruction.
• SUBJECTS AND METHODS:
• Fifteen patients with sleep apnea and five healthy volunteers underwent ultrafast MR imaging while awake and
during sleep induced with hydroxyzine hydrochloride. Sequential midline sagittal images of the pharynx were
obtained and displayed in the cine mode.
• RESULTS:
• Patients with sleep apnea were found to have sites of pharyngeal abnormality that were not present in healthy
volunteers. Nine sites of narrowing in seven patients (47%) were detected with the patient awake; 21 sites of
obstruction in 13 patients (87%) were diagnosed with the patient asleep. Six patients showed only one
obstruction, and seven had several obstructions: five had obstructions at the velum palatinum and at the
oropharynx; one had obstructions at the velum palatinum, oropharynx, and hypopharynx; one had obstructions at
the velum palatinum and the hypopharynx. The sites of narrowing during wakefulness and the sites of obstruction
during sleep were the same in only four (31%) of the patients with pharyngeal airway obstruction.
• CONCLUSION:
• Ultrafast MR imaging is useful for localizing the sites of pharyngeal airway obstruction in patients with sleep
apnea.

Thorax. 1992 Oct;47(10):809-13.Effect of reduced expiratory pressure on
pharyngeal size during nasal positive airway pressure in patients with sleep
apnoea: evaluation by continuous computed tomography.Gugger M, Vock P.
• Source
• Department of Radiology, University of Berne, Inselspital, Switzerland.
• Abstract
• BACKGROUND:
• This study aimed to determine whether reducing the expiratory pressure during nasal positive airway pressure for
reasons of comfort causes a substantial decrease in the upper airway calibre.
• METHODS:
• Eight patients with obstructive sleep apnoea were studied. Continuous computed tomography (each run lasting 12
seconds) was used to measure minimum and maximum pharyngeal cross sectional areas at the velopharynx and
the hypopharynx. Pharyngeal areas were measured while patients were awake and breathing without assistance,
during the application of 12 cm H2O continuous positive airway pressure, and during bi-level positive airway
pressure with an inspiratory pressure of 12 cm H2O and an expiratory pressure of 6 cm H2O.
• RESULTS:
• Nasal continuous positive airway pressure significantly increased the mean minimum and maximum upper airway
areas at both the velopharynx and the hypopharynx compared with normal unassisted breathing. Bi-level positive
airway pressure did not show a statistically significant increase in the minimum upper airway area at either level
compared with normal unassisted breathing. The minimum areas of the velopharynx and hypopharynx were
smaller with bi-level than continuous positive airways pressure in six of eight and eight of eight patients
respectively but these were still greater than during unassisted breathing in seven of eight and six of eight patients
respectively.
• CONCLUSIONS:
• Continuous positive airway pressure at 12 cm H2O is more effective in splinting the pharynx open than bi-level
positive airway pressure with an inspiratory positive airway pressure of 12 cm H2O and an expiratory pressure of 6
cm H2O in patients with obstructive sleep apnoea during wakefulness, suggesting an important role for expiratory
positive airway pressure. The clinical importance of this finding needs to be evaluated during sleep.

during bi-level positive airway pressure. The
circumference of the airway is outlined by automatic
electronic cursor (see Methods). R = right; L = left;S = spine. Matthias
Gugger, Peter Vock Thorax 1992;47:809-
813

Computed tomograms showing minimum (left) and maximum (right) airway
area at the velopharynx during spontaneous breathing without positive airway pressure
application (top), with constant positive airway pressure (middle) and bi-level positive
airway pressure (bottom) application. For orientation see figure 1.
Matthias Gugger, Peter Vock

• Eur Respir J. 1989 Jul;2(7):613-22.
• Sites and sizes of fat deposits around the pharynx in obese patients with obstructive sleep
apnoea and weight matched controls.
• Horner RL, Mohiaddin RH, Lowell DG, Shea SA, Burman ED, Longmore DB, Guz A.
• Source
• Department of Medicine, Charing Cross and Westminster Medical School, London, U.K.
• Abstract
• It has been suggested that deposition of fat in the soft tissues surrounding the upper airway may be
an important factor in the pathogenesis of obstructive sleep apnoea (OSA) in obese subjects. We
have used magnetic resonance imaging to determine the site(s) and size(s) of fat deposits around
the upper airway in six obese patients with OSA (116-153% of ideal body weight) and five weight-matched
controls without OSA (107-152% of ideal body weight). In all subjects, large deposits of fat
were present postero-lateral to the oropharyngeal airspace at the level of the soft palate.
Significantly more fat was present in these regions in the patients with OSA (p = 0.03). Fat deposits
in the soft palate were observed in 4 of the 6 patients with OSA but none of the controls. Fatty
streaks were observed in the tongue in 2 of the 5 controls and 3 of the 6 patients with OSA. Fat
deposits were observed anterior to the laryngopharyngeal airspace, in submental regions, in all
obese subjects. This study shows that more fat is present in those areas surrounding the
collapsable segment of the pharynx in patients with OSA, compared to equally obese control
subjects without OSA.

Clin Exp Otorhinolaryngol. 2010 Sep;3(3):147-52. Epub 2010 Sep 17.
Differences of Upper Airway Morphology According to Obesity: Study with
Cephalometry and Dynamic MD-CT.Kim TH, Chun BS, Lee HW, Kim JS.
• Source
• Department of Otorhinolaryngology-Head and Neck Surgery, Kyungpook National University School of Medicine,
Daegu, Korea.
• Abstract
• OBJECTIVES:
• We investigated difference of parameters of polysomnography, cephalometry and dynamic multi-detector
computerized tomography (MD-CT) in wake and sleep states according to obesity.
• METHODS:
• We evaluated 93 patients who underwent polysomnography and cephalometry. MD-CT was performed in 68 of
these 93 patients. Fifty-nine and 34 patients were classified as obese and non-obese, with obesity defined as BMI
≥25. Cephalometry results were analyzed for 12 variables. Using the MD-CT, we evaluated dynamic upper airway
morphology in wake and sleep states and divided the upper airway into four parts named as high retropalatal
(HRP), low retropalatal (LRP), high retroglossal (HRG), and low retroglossal (LRG). A minimal cross sectional area
(mCSA) and collapsibility index (CI) were calculated for each airway level.
• RESULTS:
• Diastolic blood pressure (P=0.0005), neck circumference (P<0.0001), and apnea-hypopnea index (P<0.0001) were
statistically significantly different between the obese and non-obese group. Among 12 cephalometric variables,
there was a significant difference in only the distance from mandibular plane to hyoid bone (P=0.003). There was
statistical difference in CI of HRG and LRG in sleep state (P=0.0449, 0.0281) but no difference in mCSA in wake and
sleep states.
• CONCLUSION:
• The obese group had more severe sleep apnea than the non-obese group. We believe that the increased severity
of apnea in the obese group may be have been due to increased collapsibility of the upper airway rather than
decreased size of the upper airway.

• Acta Otolaryngol. 2011 Jan;131(1):84-90. Epub 2010 Oct 20.
• Correlation between severity of sleep apnea and upper airway morphology: Cephalometry and MD-CT study during awake and sleep states.
• Heo JY, Kim JS.
• Source
• Department of Otorhinolaryngology-Head & Neck Surgery, Kyungpook National University, Daegu, Korea.
• Abstract
• CONCLUSION:
• The data show that the evaluation of obstruction site in patients with obstructive sleep apnea (OSA) should be performed in the sleep state rather
than in wakefulness.
• OBJECTIVE:
• The aim of this study was to identify correlation between severity of OSA as measured by the apnea-hypopnea index (AHI) and upper airway
morphology examined by cephalometry and dynamic multidetector computed tomography (MD-CT) in awake and sleep states.
• METHODS:
• Polysomnography and cephalometry were performed in 94 patients with snoring or OSA. Among them, 64 patients underwent MD-CT study.
Thirteen cephalometric variables were measured. We analyzed the correlations between AHI and MD-CT measurements - minimal cross-sectional
area (mCSA) and collapsibility index (CI) in high retropalate (HRP), low retropalate (LRP), high retroglossal (HRG), and low retroglossal (LRG) areas.
• RESULTS:
• Statistically significant correlations between the AHI and inferior displacement of the hyoid bone and pharyngeal length were identified in the
cephalometric study. In wakefulness, AHI had a negative correlation with mCSA in the LRP area and a significant correlation with CI in LRP and HRG in
MD-CT measurements. However, in the sleep state, the AHI had a negative correlation with mCSA in LRP, HRG, and LRG areas and a meaningful
correlation with CI for the whole upper airway (HRP, LRP, HRG, and LRG).

Heart Fail Rev. 2009 Sep;14(3):143-53. Epub 2008 Sep 20.
Obstructive sleep apnea: the new cardiovascular disease. Part I: Obstructive
sleep apnea and the pathogenesis of vascular disease.
Khayat R, Patt B, Hayes D Jr.
• Source
• The Ohio State University Sleep Heart Program, The Ohio State
University, 473 W 12th Ave, Suite 105, Columbus, OH 43210, USA.
• Abstract
• Obstructive sleep apnea (OSA) is increasingly recognized as a novel
cardiovascular risk factor. OSA is implicated in the pathogenesis of
hypertension, left ventricular dysfunction, coronary artery disease
and stroke. OSA exerts its negative cardiovascular consequences
through its unique pattern of intermittent hypoxia. Endothelial
dysfunction, oxidative stress, and inflammation are all
consequences of OSA directly linked to intermittent hypoxia and
critical pathways in the pathogenesis of cardiovascular disease in
patients with OSA. This review will discuss the known mechanisms
of vascular dysfunction in patients with OSA and their implications
for cardiovascular disease.

• Korean J Radiol. 2004 Apr-Jun;5(2):102-6.
• Does the oropharyngeal fat tissue influence the oropharyngeal airway in snorers? Dynamic CT study.
• Aksoz T, Akan H, Celebi M, Sakan BB.
• Source
• Department of Radiology, School of Medicine, Ondokuz Mayis University, Samsun, Türkiye. draksoz@mynet.com
• Abstract
• OBJECTIVE:
• The aim of this study was to determine if snorers have a narrower oropharyngeal airway area because of fat infiltration, and an elevated body mass
index.
• Ten control subjects and 19 patients that snored were evaluated. We obtained 2-mm-thick axial CT scan images every 0.6 seconds during expiration
and inspiration at the same level of the oropharynx. We selected the largest and the smallest oropharyngeal airway areas and found the differences.
From the slice that had the smallest oropharyngeal airway area, the thickness of the parapharyngeal and subcutaneous fat was measured. The
measurements from the left and right side were added together and single values for parapharyngeal and subcutaneous fat tissue thickness were
then found.
• RESULTS:
• The conventional measure of body mass index was significantly higher in the snorers (p < 0.05). The difference in the smallest oropharyngeal airway
area between snorers and the controls was statistically significant (p < 0.01). The average difference between the largest and the smallest
oropharyngeal area in the control group and the snorer group was statistically significant (p < 0.05). There was no significant difference in the largest
oropharyngeal airway area, the total subcutaneous fat width and the total parapharyngeal fat width between snorers and control subjects (p > 0.05).
• CONCLUSION:
• We concluded that the oropharyngeal fat deposition in snorers is not an important factor, and it does not predispose a person to the upper airway
narrowing

Airway assessment by volumetric computed tomography in
snorers and subjects with obstructive sleep apnea in a Far-East
Asian population (Chinese).
Chen NH, Li KK, Li SY, Wong CR, Chuang ML, Hwang CC, Wu YK.
• Source
• Sleep Center, Department of Otolaryngology, Chang Gung Memorial Hospital, Taipei, Taiwan.
• Abstract
• OBJECTIVES:
• To evaluate the airway dimension of simple snorers and subjects with obstructive sleep apnea (OSA) in a Far-East Asian population (Chinese).
• STUDY DESIGN:
• Prospective study of 117 near-consecutive patients evaluated for snoring and possible OSA from January 1998 to December 1998 in a sleep
laboratory. Overnight polysomnography (PSG) was performed on all patients and the sleep parameters, including respiratory disturbance index (RDI),
snoring index, minimal oxygen saturation (min O2), percentage of slow wave sleep (SWS), and rapid eye movement (REM) were recorded. Three-dimensional
computerized tomography (CT) during awake periods was performed. The anteroposterior (AP) and the lateral distance of the
retropalatal (RP) region in the oropharynx, the smallest area of RP, and retroglossal (RG) regions, and the total volume of the oropharynx were
measured.
• RESULT:
• Ninety-eight patients were diagnosed with OSA (mean RDI, 41.48 +/- 26.45 events per hour; min O2, 72.82 +/- 12.86%), whereas 19 were simple
snorers. The AP and the lateral distance of the RP region, as well as the smallest area of the RP region, are significantly smaller in subjects with OSA.
However, no differences in the RG region and the total volume of the oropharynx were found between the two groups. Linear regression analysis
demonstrated that the lateral dimension and the smallest RP area in overweight subjects inversely correlated with the RDI, but only the AP
dimension of the RP area was found to have an inverse correlation with the RDI in the underweight subjects.
• CONCLUSION:
• In Far-East Asians (Chinese), the RP airway was found to be the primary site of narrowing in subjects with OSA, and the narrowest RP area was
inversely correlated with RDI. Furthermore, weight may influence the pattern of RP narrowing by contributing to lateral collapse.

• Am J Respir Crit Care Med. 1995 Jul;152(1):179-85.
• Effects of body position on the upper airway of patients with obstructive sleep apnea.
• Pevernagie DA, Stanson AW, Sheedy PF 2nd, Daniels BK, Shepard JW Jr.
• Source
• Sleep Disorders Center, Mayo Clinic, Rochester, Minnesota 55905, USA.
• Abstract
• Fast-CT scanning was used to study the effects of changes in body position on upper airway (UA)
size and shape in 11 awake subjects with obstructive sleep apnea (OSA). Six patients with position
(P)-dependent OSA were compared with five patients with nonposition (NP)-dependent OSA. Scans
were repeated in the prone (PRN), right side (RS), and supine (SUP) body positions at both
functional residual capacity and end-inspiratory tidal volume. Significant group, group by position,
and borderline group by respiration effects were detected for minimum but not mean UA
dimension data. Significant differences between groups were noted in minimum cross-sectional
area and minimum lateral distance but not in minimum anteroposterior distance in the RS and SUP
positions. Turning from the PRN to the RS or SUP position tended to decrease UA size in the NP
group by decreasing the lateral distance, while the opposite effect was found in the P group. The
results indicate that changes in body position during wakefulness affect the lateral but not the
anteroposterior dimensions of the UA, and the UA behaves differently in patients with NP and P
OSA in response to changes in body position.

• AJNR Am J Neuroradiol. 2005 Nov-Dec;26(10):2624-9.
• Evaluation of the upper airway cross-sectional area changes in different degrees of severity of obstructive sleep apnea syndrome: cephalometric
and dynamic CT study.
• Yucel A, Unlu M, Haktanir A, Acar M, Fidan F.
• Source
• Department of Radiology, Afyon Kocatepe University School of Medicine, Afyon, Turkey.
• Abstract
• BACKGROUND AND PURPOSE:
• The upper airway lumen is narrower in patients with obstructive sleep apnea syndrome (OSAS) than normal subjects. In this study, we examined
changes of the upper airway cross-sectional area in each phase of respiration in different degrees of severity of OSAS with dynamic CT and
investigated whether these changes have any correlation with sleep apnea severity parameters, including polysomnography (PSG) and cephalometry.
• Between May and November 2004, 47 patients who had at least 2 of 3 major symptoms of snoring, daytime somnolence, and apnea with witness
were included in this prospective study. As control group, 24 habitual snorers were studied. All patients underwent PSG and upper airway CT. The
average number of episodes of apnea and hypopnea per hour of sleep (the apnea-hypopnea index, AHI) was calculated. An AHI of 5 -29 represented
mild/moderate OSAS and an AHI > or = 30 represented severe OSAS. Cross-sectional area of the airway at the level of oropharynx and hypopharynx
were obtained in each phase of quiet tidal breathing and at the end of both the forced inspiration and expiration. Six standard cephalometric
measurements were made on the lateral scout view. All parameters were compared between controls and mild/moderate and severe OSAS groups.
• RESULTS:
• Twenty-seven patients had mild/moderate OSAS, and 20 patients had severe OSAS. Patients with severe OSAS had significantly narrower cross-sectional
area at the level of uvula in expiration, more inferiorly positioned hyoid bone, and thicker soft palate compared with patients with
mild/moderate OSAS (P < .05) and the control group (P < .05). In addition, severe OSAS patients had bigger neck circumference than those in the
control group (P < .05).
• CONCLUSION:
• Patients with severe OSAS had significant differences in the parameters. Measurement of the cross-sectional area of oropharynx in expiration can
especially be useful for diagnosis of severe OSAS as a new key point.

• Chest. 2003 Jul;124(1):212-8.
• Cephalometric analysis in obese and nonobese patients with obstructive sleep apnea syndrome.
• Yu X, Fujimoto K, Urushibata K, Matsuzawa Y, Kubo K.
• Source
• First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
• Abstract
• The aims of this study were to comprehensively evaluate the cephalometric features of patients with obstructive sleep apnea syndrome (OSAS), and
to elucidate the relationship between cephalometric variables and severity of the apnea-hypopnea index (AHI).
• PATIENTS:
• The study population consisted of 62 male patients with OSAS, classified into 33 obese patients (body mass index [BMI] >or= 27) and 29 nonobese
patients (BMI < 27), and 13 male simple snorers (AHI < 5 events per hour).
• METHOD:
• and measurements: Diagnostic polysomnography and measurements of 22 cephalometric variables were carried out for all patients and simple
snorers.
• RESULTS:
• Patients with OSAS in both subgroups showed several significant cephalometric features compared with simple snorers: (1) inferiorly positioned
hyoid bone, (2) enlarged soft palate, and (3) reduced upper airway width at soft palate. More extensive and severe soft-tissue enlargements
including anteriorly positioned hyoid bone and a longer tongue were found in the obese patients. In the nonobese patients, the anteroposterior
distances of the bony nasopharynx and oropharynx were significantly smaller than those of simple snorers and obese patients. Stepwise regression
analysis showed that anterior displacement of the hyoid bone and retroposition of the mandible were the dominant overall determinants for AHI in
patients with OSAS, and that narrowing of the bony oropharynx and inferior displacement of the hyoid bone were dominant determinants for AHI in
nonobese patients. A significant regression model for AHI using cephalometric variables could not be obtained for the obese patients, but the BMI
proved to be the most significant determinant.
• CONCLUSION:
• Characteristics of the craniofacial bony structure such as narrowing of the nasopharynx and oropharynx and enlargement of the soft tissue in the
upper airway may be important risk factors for the development of OSAS in nonobese patients. In obese patients, the deposition of adipose tissue in
the upper airway may aggravate the severity of OSAS.

• Head Face Med. 2007 Dec 22;3:41.
• Obesity and craniofacial variables in subjects with obstructive sleep apnea syndrome: comparisons of
cephalometric values.
• Cuccia AM, Campisi G, Cannavale R, Colella G.
• Source
• Department of Dental Sciences G.Messina, University of Palermo, Palermo, Italy. medicinaorale@odonto.unipa.it
• Abstract
• BACKGROUND:
• The aim of this paper was to determine the most common craniofacial changes in patients suffering Obstructive
Sleep Apnea Syndrome (OSAS) with regards to the degree of obesity. Accordingly, cephalometric data reported in
the literature was searched and analyzed.
• METHODS:
• After a careful analysis of the literature from 1990 to 2006, 5 papers with similar procedural criteria were selected.
Inclusion criteria were: recruitment of Caucasian patients with an apnea-hypopnea index (AHI) >10 as grouped in
non-obese (Body Mass Index - [BMI] < 30) vs. obese (BMI > or = 30).
• RESULTS:
• A low position of the hyoid bone was present in both groups. In non-obese patients, an increased value of the
ANB angle and a reduced dimension of the cranial base (S-N) were found to be the most common finding,
whereas major skeletal divergence (ANS-PNS ;Go-Me) was evident among obese patients. No strict association
was found between OSAS and length of the soft palate.
• CONCLUSION:
• In both non-obese and obese OSAS patients, skeletal changes were often evident; with special emphasis of
intermaxillary divergence in obese patients. Unexpectedly, in obese OSAS patients, alterations of oropharyngeal
soft tissue were not always present and did not prevail.

• Obes Rev. 2011 Feb;12(2):105-13. doi: 10.1111/j.1467-789X.2010.00719.x.
• Dentofacial characteristics as indicator of obstructive sleep apnoea-hypopnoea syndrome in patients with
severe obesity.
• Maciel Santos ME, Laureano Filho JR, Campos JM, Ferraz EM.
• Source
• Department of Oral and Maxillofacial Surgery, Dentistry College of Pernambuco, University of Pernambuco,
Camaragibe, Brazil.
• Abstract
• Obstructive sleep apnoea-hypopnoea syndrome (OSAHS) is a complex disease with a multifactor aetiology. OSAHS
is strongly associated with obesity, but there are many other clinical risk factors, such as the dentofacial
characteristics of hard and soft tissues, hyoid bone position, neck circumference, upper airway spaces and nasal
respiration. A descriptive cross-sectional study was carried out involving 13 patients (one man and 12 women)
with severe obesity in order to evaluate specific physical dentofacial characteristics through a cephalometric
examination. Cephalometry was analysed using 29 measurements of the hard and soft tissues of the craniofacial
structures and dimensions of the upper airways. The demographic data revealed a mean body mass index of 48 ±
6.26 kg m(-2) and cervical circumference of 43 ± 3.69 cm. No patient exhibited important facial asymmetry and
facial types 1 (normal) and 3 (mandible forward) were the most prevalent. Septal deviation was observed in 46%
of patients. The most prevalent modified Mallampati index score was between 3 and 4, while grade 1 was the
most prevalent tonsillar hypertrophy index score (46%). Cephalometry revealed angular and linear measurements
with normally acceptable values for the hard tissues. Obese patients seem to have a normal craniofacial structure
and the risk of developing OSAHS is especially related to obesity.

• Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2010 Feb;109(2):285-93.
• Comparison of cone-beam CT parameters and sleep questionnaires in sleep apnea patients and control subjects.
• Enciso R, Nguyen M, Shigeta Y, Ogawa T, Clark GT.
• Source
• Division of Craniofacial Sciences and Therapeutics, School of Dentistry, University of Southern California, Los Angeles, California 90089-0641, USA.
renciso@usc.edu
• Abstract
• OBJECTIVE:
• The aim of this work was to compare the cone-beam computerized tomography (CBCT) scan measurements between patients with obstructive sleep
apnea (OSA) and snorers to develop a prediction model for OSA based on CBCT imaging and the Berlin questionnaire.
• STUDY DESIGN:
• Eighty subjects (46 OSA patients with apnea-hypoapnea index [AHI] >or= 10 and 34 snorers with AHI <10 based on ambulatory somnographic
assessment) were recruited through flyers and mail at the University of Southern California School of Dentistry and at a private practice. Each patient
answered the Berlin questionnaire, and was imaged with CBCT in supine position. Linear and volumetric measurements of the upper airway were
performed by one blinded operator, and multivariate logistic regression analysis was used to identify risk factors for OSA.
• RESULTS:
• The OSA patients were predominantly male and older and had a larger neck size and larger body mass index than the snorers. The minimum cross-sectional
area of the upper airway and its lateral dimension were significantly smaller in the OSA patients. Airway uniformity defined as the minimum
cross-sectional area divided by the average area was significantly smaller in the OSA patients.
• CONCLUSIONS:
• Age >57 years, male gender, "high risk" on the Berlin questionnaire, and narrow upper airway lateral dimension (<17 mm) were identified as
significant risk factors for OSA. The results of this study indicate that 3-dimensional CBCT airway analysis could be used as a tool to assess the
presence and severity of OSA. The presence and severity (as measured by the respiratory disturbance index) of OSA is associated with a narrow
lateral dimension of the airway, increasing age, male gender, and high-risk Berlin questionnaire.

• J Clin Sleep Med. 2009 Aug 15;5(4):330-4.
• The effect of acid suppression on upper airway anatomy and obstruction in patients with sleep apnea and gastroesophageal reflux disease.
• Orr WC, Robert JJ, Houck JR, Giddens CL, Tawk MM.
• Source
• Lynn Health Science Institute, University of Oklahoma Health Sciences Center Oklahoma, OK 73112, USA. worr@lhsi.net
• Abstract
• This study was designed to assess the effect of acid suppression on upper airway structure and function in patients with obstructive sleep apnea
syndrome (OSAS) and gastroesophageal reflux disease (GERD).
• METHODS:
• This is a single-site within-subjects design. Twenty five patients with documented mild OSAS and objectively documented GERD via 24-hour pH
measurement were included in the study. Patients were studied before and after 8 weeks of treatment with rabeprazole, 20 mg, twice a day.
Subjects underwent laryngoscopy, polysomnography, and 24-hour pH monitoring. Subjective assessments of sleep obtained included the Pittsburg
Sleep Quality Index and the Epworth Sleepiness Scale.
• RESULTS:
• Posterior commissure edema was significantly reduced (p < 0.05), and the Reflux Finding Score was improved (p < 0.07). Objective and subjective
sleep parameters were significantly improved, sleep-onset latency was significantly reduced (26.2 vs 11.2, p < 0.05), and sleep-related acid contact
time was significantly reduced (8.0% vs 1.7% p < 0.001). There was no significant change in the apnea-hypopnea index.
• CONCLUSIONS:
• In patients with mild OSAS and documented GERD, acid suppression improves upper airway abnormalities, as well as objective and subjective
measures of sleep quality. Aggressive treatment of GERD in patients with OSAS may be helpful in the overall treatment of this select patient
population.

• J Appl Physiol. 2010 Feb;108(2):430-5. Epub 2009 Oct 29.
• Obesity and upper airway control during sleep.
• Schwartz AR, Patil SP, Squier S, Schneider H, Kirkness JP, Smith PL.
• Source
• Sleep Disorders Center, Johns Hopkins School of Medicine, Baltimore, Maryland 21224, USA.
aschwar2@jhmi.edu
• Abstract
• Mechanisms linking obesity with upper airway dysfunction in obstructive sleep apnea are reviewed.
Obstructive sleep apnea is due to alterations in upper airway anatomy and neuromuscular control.
Upper airway structural alterations in obesity are related to adipose deposition around the
pharynx, which can increase its collapsibility or critical pressure (P(crit)). In addition, obesity and,
particularly, central adiposity lead to reductions in resting lung volume, resulting in loss of caudal
traction on upper airway structures and parallel increases in pharyngeal collapsibility. Metabolic
and humoral factors that promote central adiposity may contribute to these alterations in upper
airway mechanical function and increase sleep apnea susceptibility. In contrast, neural responses to
upper airway obstruction can mitigate these mechanical loads and restore pharyngeal patency
during sleep. Current evidence suggests that these responses can improve with weight loss.
Improvements in these neural responses with weight loss may be related to a decline in systemic
and local pharyngeal concentrations of specific inflammatory mediators with somnogenic effects.

• Sleep. 2008 Nov;31(11):1543-9.
• Effect of body posture on pharyngeal shape and size in adults with and without obstructive sleep apnea.
• Walsh JH, Leigh MS, Paduch A, Maddison KJ, Armstrong JJ, Sampson DD, Hillman DR, Eastwood PR.
• Source
• West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Nedlands, Western Australia. Jennifer.Walsh@health.wa.gov.au
• Abstract
• In patients with obstructive sleep apnea (OSA), the severity and frequency of respiratory events is increased in the supine body posture compared
with the lateral recumbent posture. The mechanism responsible is not clear but may relate to the effect of posture on upper airway shape and size.
This study compared the effect of body posture on upper airway shape and size in individuals with OSA with control subjects matched for age, BMI,
and gender.
• PARTICIPANTS:
• 11 males with OSA and 11 age- and BMI-matched male control subjects.
• RESULTS:
• Anatomical optical coherence tomography was used to scan the upper airway of all subjects while awake and breathing quietly, initially when supine,
and then in the lateral recumbent posture. A standard head, neck, and tongue position was maintained during scanning. Airway cross-sectional area
(CSA) and anteroposterior (A-P) and lateral diameters were obtained in the oropharyngeal and velopharyngeal regions in both postures. A-P to lateral
diameter ratios provided an index of regional airway shape. In equivalent postures, the ratio of A-P to lateral diameter in the velopharynx was similar
in OSA and control subjects. In both groups, this ratio was significantly less for the supine than for the lateral recumbent posture. CSA was smaller in
OSA subjects than in controls but was unaffected by posture.
• CONCLUSIONS:
• The upper airway changes from a more transversely oriented elliptical shape when supine to a more circular shape when in the lateral recumbent
posture but without altering CSA. Increased circularity decreases propensity to tube collapse and may account for the postural dependency of OSA.

Upper airway neuromuscular
compensation during sleep is
defective in obstructive sleep apnea
• J Appl Physiol. 2008 Jul;105(1):197-205. Epub 2008 Apr 10.
• Upper airway neuromuscular compensation during sleep is defective in obstructive sleep apnea.
• McGinley BM, Schwartz AR, Schneider H, Kirkness JP, Smith PL, Patil SP.
• Source
• Johns Hopkins Sleep Disorders Center, Division of Pulmonary and Critical Care Medicine, Johns Hopkins University,
Baltimore, MD 21224, USA. bmcginley@jhmi.edu
• Abstract
• Obstructive sleep apnea is the result of repeated episodes of upper airway obstruction during sleep. Recent
evidence indicates that alterations in upper airway anatomy and disturbances in neuromuscular control both play
a role in the pathogenesis of obstructive sleep apnea. We hypothesized that subjects without sleep apnea are
more capable of mounting vigorous neuromuscular responses to upper airway obstruction than subjects with
sleep apnea. To address this hypothesis we lowered nasal pressure to induce upper airway obstruction to the
verge of periodic obstructive hypopneas (cycling threshold). Ten patients with obstructive sleep apnea and nine
weight-, age-, and sex-matched controls were studied during sleep. Responses in genioglossal electromyography
(EMG(GG)) activity (tonic, peak phasic, and phasic EMG(GG)), maximal inspiratory airflow (V(I)max), and
pharyngeal transmural pressure (P(TM)) were assessed during similar degrees of sustained conditions of upper
airway obstruction and compared with those obtained at a similar nasal pressure under transient conditions.
Control compared with sleep apnea subjects demonstrated greater EMG(GG), V(I)max, and P(TM) responses at
comparable levels of mechanical and ventilatory stimuli at the cycling threshold, during sustained compared with
transient periods of upper airway obstruction. Furthermore, the increases in EMG(GG) activity in control
compared with sleep apnea subjects were observed in the tonic but not the phasic component of the EMG
response. We conclude that sustained periods of upper airway obstruction induce greater increases in tonic
EMG(GG), V(I)max, and P(TM) in control subjects. Our findings suggest that neuromuscular responses protect
individuals without sleep apnea from developing upper airway obstruction during sleep.
• PMID: 18403451 [PubMed - indexed for MEDLINE

• Sleep. 2007 Nov;30(11):1503-8.
• Sonographic measurement of lateral parapharyngeal wall thickness in patients with obstructive sleep apnea.
• Liu KH, Chu WC, To KW, Ko FW, Tong MW, Chan JW, Hui DS.
• Source
• Department of Diagnostic Radiology and Organ Imaging, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong.
tongyc@netvigator.com
• Abstract
• INTRODUCTION:
• Lateral parapharyngeal wall (LPW) thickness may be a predominant anatomic factor causing airway narrowing in apneic subjects. In this study, we
explored sonographic measurement of the LPW thickness and compared the results with LPW thickness measured by magnetic resonance imaging
(MRI). We also investigated the association between sonographic measurement of LPW thickness and apnea-hypopnea index (AHI).
• METHOD:
• Seventy-six patients with suspected obstructive sleep apnea (OSA) underwent ultrasound examination of LPW thickness after overnight
polysomnography. Fifteen out of 76 subjects also participated in correlation and reliability studies of sonographic and MRI measurements of LPW
thickness.
• RESULTS:
• There was good correlation between measurements of LPW thickness on ultrasound and MRI (r = 0.78, P = 0.001), although Bland-Altman analysis
indicated overestimation of LPW thickness by ultrasound, when compared with the LPW as measured by MRI. The sonographic measurement of LPW
thickness had high reproducibility, with intraclass correlation coefficients of 0.90 and 0.97 for intraoperator and interoperator reliability, respectively.
Fifty-eight subjects with significant OSA (AHI > or = 10/h) had a higher body mass index, larger neck circumference, and greater LPW thickness
measured by ultrasound than those (n = 18) with an AHI of less than 10 per hour. LPW thickness had a positive correlation with AHI on univariate
analysis (r = 0.37, P = 0.001). On multivariate analysis, LPW thickness had a positive independent association with AHI after adjustment for age, sex,
neck circumference, and body mass index. The positive association of LPW thickness with AHI remained significant in both univariate and multivariate
analyses of men only (n = 62).
• CONCLUSIONS:
• Sonographic measurement of LPW thickness is a novel and reliable technique and had good correlations with measurement by MRI and the severity
of OSA. Ultrasound may provide an alternative imaging modality with easy accessibility and lower cost in OSA research.

• Respir Physiol Neurobiol. 2008 Jan 1;160(1):1-7. Epub 2007 Aug 3.
• Pharyngeal motor control and the pathogenesis of obstructive sleep apnea.
• Jordan AS, White DP.
• Source
• Brigham and Women's Hospital, Boston, MA 02115, United States. ajordan@rics.bwh.harvard.edu
• Abstract
• The upper airway in patients with obstructive sleep apnea (OSA) is thought to collapse during sleep
at least in part, because of a sleep related reduction in upper airway dilator muscle activity.
Therefore, a comprehensive understanding of the neural regulation of these muscles is warranted.
The dilator muscles can be classified in two broad categories; those that have respiratory related
activity and those that fire constantly throughout the respiratory cycle. The motor control of these
two groups likely differs with the former receiving input from respiratory neurons and negative
pressure reflex circuits. The activity of both muscle groups is reduced shortly after sleep onset,
indicating that both receive input from brainstem neurons involved in sleep regulation. In the
apnea patient, this may lead to pharyngeal airway collapse. This review briefly describes the
currently proposed sleep and respiratory neural pathways and how these circuits interact with the
upper airway dilator muscle motorneurones, including recent evidence from animal studies.

• Chest. 2007 Jul;132(1):325-37.
• Adult obstructive sleep apnea: pathophysiology and diagnosis.
• Patil SP, Schneider H, Schwartz AR, Smith PL.
• Source
• Department of Medicine, Division of Pulmonary and Critical Care Medicine, Baltimore, MD 21224,
USA. spatil@jhmi.edu
• Abstract
• Obstructive sleep apnea (OSA) is a highly prevalent disease characterized by recurrent episodes of
upper airway obstruction that result in recurrent arousals and episodic oxyhemoglobin
desaturations during sleep. Significant clinical consequences of the disorder cover a wide spectrum,
including daytime hypersomnolence, neurocognitive dysfunction, cardiovascular disease, metabolic
dysfunction, and cor pulmonale. The major risk factors for the disorder include obesity, male
gender, and age. Current understanding of the pathophysiologic basis of the disorder suggests that
a balance of anatomically imposed mechanical loads and compensatory neuromuscular responses
are important in maintaining upper airway patency during sleep. OSA develops in the presence of
both elevated mechanical loads on the upper airway and defects in compensatory neuromuscular
responses. A sleep history and physical examination is important in identification of patients and
appropriate referral for polysomnography. Understanding nuances in the spectrum of presenting
complaints and polysomnography correlates are important for diagnostic and therapeutic
approaches. Knowledge of common patterns of OSA may help to identify patients and guide
therapy.

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