LwPTL: a novel classification for upper airway collapsein sleep endoscopies�
Ahmed Elsobki a,∗, Michel Burihan Cahalib, Mohamed Kahwagia
a University Mansoura, Department of Otorhinolaryngology, Mansoura, Egyptb Universidade de São Paulo (USP), Hospital das Clínicas, Departamento de Otorrinolaringologia, São Paulo, SP, Brazil
Received 23 July 2018; accepted 6 January 2019Available online 8 March 2019
KEYWORDSPharynx;Epiglottis;Tongue;Endoscopy
AbstractIntroduction: There is no consensus on a single classification system for the obstructive findingsin drug-induced sleep endoscopy. Previous classification systems have neglected to address theupper retropalatal obstruction, the segmental division of the lateral pharyngeal wall and theprimary or secondary nature of laryngeal collapse.Objective: To propose, illustrate and evaluate a more comprehensive and yet simple classifi-cation for drug-induced sleep endoscopy findings.Methods: Cross sectional study in a tertiary sleep surgery unit. A total of 30 patients withobstructive sleep apnea underwent drug-induced sleep endoscopy according to a new classi-fication system called LwPTL, and its findings were analyzed according to obstructive sleepapnea severity and body mass index. LwPTL incorporates the description of upper retropalatalcollapse, distinguishes the lateral pharyngeal wall collapse into three levels and clarify whenlaryngeal collapses are primary or secondary.Results: 93.3% of the patients presented lateral pharyngeal wall collapse, usually at the level ofthe velum (73.3%). 80% presented multilevel collapse. Regarding the upper retropalatal region,LwPTL identified 10% of the cases presenting lateral salpingopharyngeal obstruction and 6.6%
with high palatal collapse. 3.3% presented epiglottic collapse. Patients presenting lower levelsof collapse, either from the lateral wall and/or tongue and/or larynx, represented 30% of thecases and had significantly more severe obstructive sleep apnea, without significant differencesin body mass indexes.
� Please cite this article as: Elsobki A, Cahali M, Kahwagia M. LwPTL: a novel classification for upper airway collapse in sleep endoscopies.Braz J Otorhinolaryngol. 2019;85:379---87.
bstructive sleep apnea (OSA) is a multifactorial disease.ultiple pathophysiological mechanisms contribute to air-ay collapse including anatomical narrowing of the upperirway, poor upper airway dilator muscle activity, lowrousal threshold and ventilatory control instability.1 Theharyngeal airway collapses when inspiratory transpharyn-eal pressure exceeds the action of the pharyngeal dilatoruscles.2 Upper airway collapse may occur in four sites; softalate, tongue, lateral pharyngeal walls and the larynx.3
Considering the wide variety of surgical procedures cur-
ently available for treating chronic snoring and OSA, thessessment of the site(s) of upper airway obstruction ismportant for selecting the appropriate procedure. Multi-le evaluation techniques have been developed to examine
ptef
n individual’s pattern of upper airway obstruction.4 Drug-nduced sleep endoscopy (DISE) has been introduced byroft and Pringle in 1991.5 Today, DISE represents the mostidespread diagnostic tool for upper airway endoscopicvaluation of snoring and OSA.6 All available DISE classifica-ion systems are based on anatomical information only7 and,n spite of that, the European Position meeting on DISE haseached no consensus on a scoring and classification systemor DISE findings.6
Previous classification systems have neglected to addresshe upper retropalatal obstruction, the segmental divisionf the lateral pharyngeal wall and the detailed structuralattern of primary or secondary laryngeal collapse. In order
o address these issues, we aim to propose, illustrate andvaluate a more comprehensive and yet simple classificationor DISE findings, which we called LwPTL.
LwPTL: a novel classification for upper airway collapse in sle
Methods
After becoming experienced with both DISE technique andour proposed classification system, we have collected dataon the last 30 consecutive OSA patients that underwent DISEand upper airway surgery at the Mansoura University Hospi-tal, a tertiary referral sleep surgery unit in Egypt.
All patients underwent level 1 polysomnography pre-operatively (transcutaneous pulse oximetry was used tomonitor oxygen saturation and heart rate. The sleeparchitecture was recorded using electroencephalogram,electro-oculogram and submental electromyogram. Wemeasured thoracic and abdominal effort, movements oflimbs, oronasal airflow, and a sensor for snoring). The sever-ity of OSA is expressed in the apnea---hypopnea index (AHI).Obstructive apneas were defined as cessation of airflow forat least 10 s. Hypopneas were defined as periods of reduc-tion of >30% in oronasal airflow for at least 10 s associatedwith a >4% decrease in oxygen saturation. The AHI was cal-culated as the sum of total events (apneas and hypopneas)per hour of sleep.
All patients had preoperative DISE for assessment ofobstruction levels. We applied our new staging system forDISE findings and correlated the data with the OSA severityand body mass index (BMI).
Inclusion criteria
Age from 18 to 50 years old;Available level one sleep study;OSA patients with AHI > 5 with CPAP failure or refusal.
lTos
Table 1 The LwPTL classification for DISE.
Structure Pattern
Lateral wall(Lw)
LS LV LH
Palate PH PL
PLobP0Nco
Tongue base TH TL
TLcoTHT0
Larynx L0 L1L0
Special tests Trans oralDISE/positionalDISE/Emrich maneuver
or our DISE technique, the patient was in a supine positionn the operating table. The patients had basic cardiore-piratory monitoring (pulse oximetry, blood pressure, andlectrocardiogram). The target depth of sedation is theransition from consciousness to unconsciousness (loss ofesponse to verbal stimulation), in practical terms, whenhe patient started to snore and choke. This description forhe desired level of sedation is because we do not havehe bispectral index monitoring in our department. Atropineas used for all patients once 30 min before anesthesia at
dose of (0.6 mg/kg) as it is anticholinergic drug whichecreases saliva during evaluation. Sleep was induced usingropofol in a dose of (1.5 mg/kg) as a bolus and then main-ained with simply manual controlled infusion. Propofol isn ultra-short acting hypnotic that enables greater controlf the depth of sedation during sleep endoscopy. So, slowtepwise induction was used to avoid oversedation. Deeperevels of sedation are associated with progressive decreasesn both upper airway dilator muscle tone and neuromuscu-
ar reflex activation, which increase airway collapsibility.o avoid overestimation of airway collapse, collapses thatccurred while oxygen saturation was less than the minimalaturation in the polysomnography were disregarded.
Comment
LS (Lw atsalpingopharyngeal folds)LV (Lw at velum)LH (Lw at hypopharynx)Combinations (LSV, etc.)Lw0: no collapsePHL: (high palate collapse)vertical palate
: (low palate collapse)lique palate: no collapse
ever PH (high palatellapse) only
TH: high tongue basecollapse
: low tongue basellapseL: both: no tongue collapse
L1: laryngeal collapse: no collapse
3 Elsobki A et al.
twws
L
OciiTioo
LWgaot
Fw
Fw
Figure 3 Fiberoptic view of LH collapse, Lateral pharyngealwall collapse at the level of the hypopharynx.
82
Once the patient has reached a satisfactory level of seda-ion, a flexible endoscope lubricated with lidocaine 2% gelas introduced into the nasal cavity. The lateral pharyngealall, soft palate, tongue base and larynx were observed. The
ites generating snoring and/or obstruction were assessed.
wPTL staging system
ur experience with DISE examination suggested that thislassification could guide the management protocol. Accord-ng to data gained from DISE we classified airway collapsento four levels: Lateral pharyngeal Wall (LW), Palate (P),ongue (T) and Larynx (L) (Table 1). In all levels, we get qual-tative information only, i.e., the collapse is either presentr absent. Collapse here means total or near total visualbstruction.
ateral pharyngeal wall collapse: (Lw)e subclassified it into collapse at the Level of the Salpin-
eopharyngeal folds (LS) (Fig. 1), of the Velum (LV) (Fig. 2)nd of the Hypopharynx (LH) (Fig. 3). Combination of 2 or 3f these levels may occur (LSV, LVH and LSVH). LS means thathe collapse occurs at the level of the salpingeopharyngeal
igure 1 Fiberoptic view of LS collapse, Lateral pharyngealall collapse at the level of the salpingeopharyngeal folds.
igure 2 Fiberoptic view of LV collapse, Lateral pharyngealall collapse at the level of the velum.
Fl
fiejlhfidc
PPcPmcncscb
igure 4 Fiberoptic view of PHL collapse, High palatal col-apse.
olds while the velum is patent. Although this pattern isnfrequent, it seems important to identify it to avoid unnec-ssary palatal surgery because this patient may respond toust fold reduction. LV means a lateral wall collapse at theevel of the velar segment of the soft palate not caused byypertrophic folds; any tonsillar level collapse is also classi-ed as LV. LH means collapse of the lateral pharyngeal wallistal to the tonsils, sometimes causing secondary epiglotticollapse by pushing the epiglottis from side to side.
alatal level of collapse: (P)alatal collapse refers to anteroposterior collapse only. Welassified it according to Woodson classification8 into Highalatal Collapse (PHL) (Fig. 4) which means collapse of theuscular and aponeurotic segments of the soft palate (the
ollapse occurs on both high and low levels so PH alone doesot exist) and low Palatal Collapse (PL) (Fig. 5) which means
ollapse of the distal segment of the soft palate. Althoughomehow popular description of collapse, we think that cir-ular collapse of the palate is a misleading term, because itrings attention to the palate where we believe the major
LwPTL: a novel classification for upper airway collapse in sleep endoscopies 383
Figure 5 Fiberoptic view of PL collapse, Low palatalcollapse.
Figure 8 Fiberoptic view of Epiglottic collapse (Floppyepiglottis).
Figure 6 Fiberoptic view of TH collapse, High tongue col-lapse.
pathophysiological components of that collapse is the lateralwall. Therefore we preferred not to use the term circularpalatal collapse in our classification and instead, individu-alized the structures involved in that pattern of collapse(LvPl).
Tongue base collapse: (T)We classified tongue base collapse into High Tongue basecollapse (TH) (Fig. 6) which means collapse of the orop-haryngeal tongue (above the level of epiglottis) and lowtongue base collapse (at or below the level of epiglottis)(TL) (Fig. 7) which means collapse of the hypopharyngealtongue causing secondary epiglottic collapse.
Laryngeal collapse: (L)Any site of laryngeal collapse not caused by low tongue basecollapse or lateral wall hypopharyngeal collapse is put under
category Larynx (L) including epiglottic (Fig. 8), aryepiglot-tic or arytenoid collapse (Fig. 9). Primary laryngeal collapsemeans that the larynx collapses on its own like the situationin floppy epiglottis while secondary collapse means that
Figure 9 Fiberoptic view of Arytenoid collapse.
384
Figure 10 Fiberoptic view of transoral DISE showing the oraltongue not pushing the palate (negative tongue palate interac-tion).
Ft
nh
SSttatDbtaia
tc
gt
sw
S
DedobMt
R
Acm(
tps((
(tspLpi
lCctcicci
(2ppetw
l
D
igure 11 Fiberoptic view of transoral DISE showing the oralongue pushing the palate (positive tongue palate interaction).
eighboring structures like base tongue and lateral wallypopharynx push on the laryngeal inlet while collapsing.
pecial testspecial tests were done when needed; we performed posi-ional DISE by rotating the head to one side. In addition,ransoral DISE was done to assess the tongue palate inter-ction (sometimes the palate is being pushed by the oralongue, which might need correction) (Figs. 10 and 11).uring transoral DISE the endoscope is smoothly pushedetween the upper and lower incisors with no need to openhe mouth to avoid the effect of mouth breathing on upperirway structures. In addition, jaw thrust is performed dur-ng DISE to detect the possible benefit of a mandibulardvancement device.
According to the staging system summarized in Table 1,he first author suggests this classification to guide the surgi-
al procedure selection according to the scheme in Fig. 12.
The rationale for using transpalatal advancement pharyn-oplasty for treating the lateral pharyngeal wall collapse athe hypopharyx is to benefit from the anterior traction of the
Ttsa
Elsobki A et al.
oft palate to increase the tension at the lateral pharyngealalls more distally.
tatistical analysis
ata was analyzed using (Statistical Package for Social Sci-nces) SPSS version 15. Quantitative normally distributedata was presented as mean ± SD. Comparison of continu-us data like AHI and BMI as regard to each level of collapseeing present or absent was done using Student t-test andann---Whitney test; p-value < 0.05 was considered to be sta-
istically significant.
esults
fter analyzing the data gained from DISE, weould find the following in the 30 patients withedian AHI (31.72 ± 20.39 events/h) and mean BMI of
32.97 ± 2.77 kg/m2).Only 11 patients (36.6%) had one level of collapse and
he other 19 patients (63.3%) had multilevel collapse. Theresence of the multilevel pattern, compared to those withingle level collapse, implied in a significant increase in AHIp = 0.003), without significant differences in BMI (p = 0.50)Table 2).
Lateral Wall collapse (Lw) was present in 28 patients93.3%) and this emphasizes our look for the importance ofhe lateral wall collapse in OSA patients. Segmental clas-ification of lateral wall collapse showed that of those 28atients we could find 3 patients with LS, 22 patients withV and 3 patients with LH. The presence of LH pattern, com-ared to those without LH collapse, implied in a significantncrease in AHI (p < 0.0001) and in BMI (p < 0.002) (Table 3).
According to Woodson classification,8 Low Palatal Col-apse (PL) was found in 18 patients (60%) while High Palatalollapse (PHL) was found in only 2 patients (6.6%). Circularollapse at the level of the velum meaning LvPl was encoun-ered in 10 patients (33.3%). The presence of PHL pattern,ompared to those without PHL collapse, implied in a signif-cant increase in AHI (p = 0.011) (Table 4). The presence ofircular collapse at the palate, compared to those withoutircular collapse, did not imply in any significant differencen AHI or in BMI (Table 5).
Low Tongue base collapse (TL) was found in 4 patients13.3%) and High Tongue base collapse (TH) was found in
patients(6.6%). Laryngeal collapse was found in only oneatient (3.3%), who had primary epiglottic collapse. Patientsresenting the lower levels of collapse, either from the lat-ral wall and/or tongue and/or larynx, represented 30% ofhe cases and had significantly more severe OSA (p = 0.0008),ithout significant differences in BMI (Table 6).
Fig. 13 summarizes the frequency of the patterns of col-apse in our series, using the LwPTL classification for DISE.
iscussion
here is currently no universally accepted classification sys-em for the data obtained from DISE. Some classificationystems prefer to use anatomical levels while others prefernatomical structures. About 14 classification systems and
LwPTL: a novel classification for upper airway collapse in sleep endoscopies 385
Lw
LS Coblation ass isted reduction of thefolds
LV
No previous tonsillectomyWide posterior pillar:
relocation pharyngo plasty
Narrow po sterior pil lar: Cahalilateral ph aryngop lasty
Previous tonsillectomyCahali lateral ph aryngop lasty or
Expansion sph incterpharyngoplasty
LHExp ansion sphincter pharyngo plasty or
Transpalatal adv ancementpharyngop lasty
P
PL Anterior palatop lasty
PHLTranspalatal advancement pharyngoplasty orMMA according to craniofacial morphology
T
TH
Geniog loss us advancement orTon gue suspension sutures
MMA according to craniofacial morphology
TL Midline glossec tomy
L
epiglott ic collapse partial epiglottec tomy
aryteno id collapse laser ablation of aryteno id mucosa
A
B
C
D
Figure 12 Brief schematic presentation for surgical approach used according to classification system: (A) for Lw, lateral pharyngealwall collapse and subdivisions; (B) for P, Palatal collapse and subdivisions; (C) for T, tongue collapse and subdivisions; (D) for L,laryngeal collapse.
Table 2 Statistical analysis of the difference inApnea---Hypopnea Index (AHI) and Body Mass Index (BMI)between patients with multilevel collapse and those withsingle level of collapse.
Table 3 Statistical analysis of the difference inApnea---Hypopnea Index (AHI) and Body Mass Index (BMI)between patients with LH (lateral wall collapse at theHypopharynx) and those without LH.
3 modifications for the structures that collapse in DISE havebeen identified till now.6,7 Croft and Pringle proposed thefirst concept of a DISE classification system which consistsof three categories.5 The proposed classification system waseasy to understand. However, it was incomplete for detailed
analysis and reporting DISE findings. Since that classification,many appeared with many modifications.9---16
ca
The VOTE classification was the first to analyze theata obtained from DISE encompassing the degree and con-guration of the obstruction related to the 4 structuresvelum, oropharynx, tongue and epiglottis).12 However, Ker-zian et al. mentioned that the limitation of The VOTE
lassification was an oversimplification that overlooks inter-ctions between the upper airway structures.4
386
Table 4 Statistical analysis of the difference inApnea---Hypopnea Index (AHI) and Body Mass Index (BMI)between patients with PHL (High Palatal Collapse) and thosewithout PHL.
Table 5 Statistical analysis of the difference inApnea---Hypopnea Index (AHI) and Body Mass Index (BMI)between patients with circular collapse and those withoutcircular collapse.
Table 6 Statistical analysis of the difference inApnea---Hypopnea Index (AHI) and Body Mass Index (BMI)between patients with hypopharyngeal collapse (LH, LateralHypopharyngeal wall; TH, High Tongue base; TL, LowTongue base; L, Larynx), and those without hypopharyngealcollapse.
Figure 13 Percent distribution of each level of collapse usingthe LwPTL classification for DISE (LS, Lateral wall collapse atthe level of salpingeopharyngeal fold; LV, Lateral wall collapseat the level of the velum; LH, Lateral wall hypopharyngealcollapse; PL, Low palatal collapse; PHL, High and low palatalcc
iatleb
ipc
dIiiabacit
srdtms
dpadi
ovatTtsc
ltTsh
hitriwisspaggap
L
ollapse; TL, Low tongue base collapse; TH, High tongue baseollapse; L, Primary laryngeal collapse).
Proper lateral wall splinting is still one of the limitationsn sleep surgery. Improving outcomes may arise from a moreccurate evaluation. In our view, it is an over simplificationo describe the whole lateral pharyngeal wall as a singleevel of collapse. Lateral wall collapse should be thouroughlyvaluated, segmentally classified and accordingly managed,ecause it does not collapse as one single unit.17
Recently we used transoral DISE to look at tongue palatenteraction and to see if the oral tongue is pushing the softalate or not. We could find that there is tongue palateontact in almost all patients. However, this simple contact
Tft
Elsobki A et al.
id not seem to affect the collapsibility of the soft palate.n only one case out of the thirty patients we found a pos-tive tongue palate interaction, meaning that we had thempression that this palate was being pushed by the tonguend, actually, this did not change our procedure selectionecause tongue palate interaction is not yet taken intoccount in our treatment protocols. Future follow-ups onases presenting that feature are important for establish-ng whether tongue base management is required or not inhose cases.
The severity of upper airway collapse in patients withleep apnea may decrease significantly when the head isotated to the lateral side. However, there is no significantifference between the rotation of the head to the right oro the left side.18 Adding this positional maneuver into DISEay provide important insights regarding where the primary
ite of obstruction is located.In our classification, we intentionally did not quantify the
egree of obstruction because there is no data showing anyhysiological meaning for partial visual collapses and usu-lly a partial obstruction does not produce a recognizableecrease in flow,19 also, this simplification would potentiallymprove inter examiner agreement.
Woodson 2015 described 3 patterns for palatal morphol-gy: the oblique palate in which the narrowing is at theelum, the intermediate palate in which the narrowing ist the velum and genu and the vertical palate at whichhe narrowing is at the velum, genu and the hard palate.hese patterns were the rationale for selecting patients forhe transpalatal advancement procedure.8 Our classificationystem incorporates that rationale, where PHL implies verti-al palate morphology and PL implies an oblique morphology.
The classification of tongue base collapse into high orow would guide the procedure selection, respectively,oward bony framework surgery or tongue base reduction.o avoid overestimation of the laryngeal level of collapse,econdarily pushed epiglottis by low tongue base or lateralypopharyngeal wall are described with the pushing level.
The European position paper stated that: ‘‘hypopharynxas its superior limit at the level of the hyoid bone, where its contiguous with the oropharynx and the major subsites ofhe hypopharynx are the pyriform sinuses, the post-cricoidegion, and the pharyngeal wall. Therefore, this region is notnvolved in the collapse’’.20 We respect the statement, bute also think that everyone should recognize how unlikely it
s to identify the hyoid bone during DISE and, therefore, wetill look at the hypopharyngeal lateral wall in sleep endo-copic terms, naming it to the most distal part of the lateralharyngeal wall. It is important to individualize the collapsest that particular level in order to tailor an appropriate sur-ical treatment for that region. In our sample, collapsesenerated from structures located at the hypopharynx weressociated with significantly higher AHI- but not be BMI com-ared to those without hypopharyngeal obstruction.
imitation of the study
he small number of patients in our study is one limitationor a more robust statistical analysis. Another limitation ishat we are not presenting the impact of this staging system
ep e
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LwPTL: a novel classification for upper airway collapse in sle
on the outcomes of the surgical procedure selected, which isstill under investigation and makes room for future studies.
Conclusion
LwPTL seems a simple and straightforward staging systemfor classifying DISE, being the first to segmentally evaluatethe lateral pharyngeal wall collapse and to distinguish theimportant upper retropalatal obstruction and to standard-ize primary and secondary laryngeal collapse. Application ofthis simplified detailed staging system may help with accu-rate surgical planning.
Conflicts of interest
The authors declare no conflicts of interest.
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