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\begin{document}

\title{Changes in the laryngopharyngeal reflux After UPPP for OSA: A Clinical
Observational Study}



\author[1]{Xiaojun Tang}%
\author[1]{Shisheng Li}%
\author[1]{Xinming Yang}%
\author[1]{qinglai Tang}%
\author[1]{ying zhang}%
\author[1]{shiying zeng}%
\author[1]{mengmeng li}%
\author[1]{kang jiang}%
\author[1]{lu guo}%
\author[1]{peiying huang}%
\affil[1]{Second Xiangya Hospital}%


\vspace{-1em}



  
  \date{May 29, 2024}


\begingroup
\let\center\flushleft
\let\endcenter\endflushleft
\maketitle
\endgroup





\selectlanguage{english}
\begin{abstract}
Objectives. The study used re\selectlanguage{ngerman}¬flux symptom index (RSI) and Reflux
Finding Score (RFS) questionnaire to estimate laryngopharyngeal reflux
(LPR) change after uvulopalatopharyngoplasty (UPPP) for obstructive
sleep apnea (OSA). Design. An observational, retrospective study.
Setting. University, tertiary level hospital. Participants. 91 subjects
were recruited and divided into three groups: control group (n=27), OSA
mild to moderate group (n=29) and OSA severe group (n=35) according to
polysomnography. All subjects completed preoperative RSI and RFS under
electronic laryngoscope. 34 OSA patients with UPPP surgery completed
postoperative polysomnography, again after 6-month follow-up. Main
outcome measures. Polysomnography, RSI and RFS questionnaire. Results.
RSI and RFS in OSA patients were higher than non-OSA patients. Severe
OSA patients also had higher RSI and RFS than mild to moderate OSA. LPR
symptoms had positive and L-SpO2 had negative correlation with AHI and
CT90. The mean RSI and RFS before UPPP surgery were 15.88±4.85 and
13.18±4.80; these number decreased to 9.53±4.16 and 8.65±4.87 after
surgery (P\textless{}0.05). In 25 successful-surgery patients, RSI and
RFS scores and individual variables of RSI were downward after surgery.
Conclusion. LPR symptoms are common among OSA patients, the coexistence
of OSA and LPR cannot be ignored. Successful UPPP surgery as a treatment
for OSA patients, poten¬tially reduces laryngeal reflux symptoms and
improves laryngoscope signs by alleviating sleep respiratory disorder.%
\end{abstract}\selectlanguage{ngerman}%



\sloppy


\textbf{Changes in the laryngopharyngeal reflux After UPPP for OSA: A
Clinical Observational Study}

\textbf{Abstract}

Objectives. The study used reflux symptom index (RSI) and Reflux
Finding Score (RFS) questionnaire to estimate laryngopharyngeal reflux
(LPR) change after uvulopalatopharyngoplasty (UPPP) for obstructive
sleep apnea (OSA).

Design. An observational, retrospective study.

Setting. University, tertiary level hospital.

Participants. 91 subjects were recruited and divided into three groups:
control group (n=27), OSA mild to moderate group (n=29) and OSA severe
group (n=35) according to polysomnography. All subjects completed
preoperative RSI and RFS under electronic laryngoscope. 34 OSA patients
with UPPP surgery completed postoperative polysomnography, again after
6-month follow-up.

Main outcome measures. Polysomnography, RSI and RFS questionnaire.

Results. RSI and RFS in OSA patients were higher than non-OSA patients.
Severe OSA patients also had higher RSI and RFS than mild to moderate
OSA. LPR symptoms had positive and L-SpO2 had negative correlation with
AHI and CT90. The mean RSI and RFS before UPPP surgery were 15.88\selectlanguage{ngerman}±4.85
and 13.18±4.80; these number decreased to 9.53±4.16 and 8.65±4.87 after
surgery (P\textless{}0.05). In 25 successful-surgery patients, RSI and
RFS scores and individual variables of RSI were downward after surgery.

Conclusion. LPR symptoms are common among OSA patients, the coexistence
of OSA and LPR cannot be ignored. Successful UPPP surgery as a treatment
for OSA patients, potentially reduces laryngeal reflux symptoms and
improves laryngoscope signs by alleviating sleep respiratory disorder.

\textbf{Key points:}

(1) The presence of laryngopharyngeal re\selectlanguage{english}flux (LPR) in obstructive sleep
apnea (OSA) is very frequent.

(2) Chronic upper airway inflammation is the result of many conditions,
among which OSA and LPR are two reasons that cannot be ignored.

(3) Uvulopalatopharyngoplasty is a useful treatment of OSA. It is still
controversial that whether it improves LPR.

(4) Re\selectlanguage{english}flux Symptom Index (RSI) and Reflux Finding Score (RFS) are more
commonly used and useful in diagnosing LPR and quantifying the severity
of LPR symptoms.

(5) The present study revealed the coexistence of OSA and LPR is common.
Successful UPPP surgery as a treatment for OSA patients can improve LPR.

\textbf{Introduction}

Obstructive sleep apnea (OSA) is a growing public health problem. About
2\%--4\% of middle-aged adults have OSA.\textsuperscript{1} Middle-aged
people suffer from sleep-disordered breathing with a high percentage of
83.\textsuperscript{2} Repetitive collapse and reopening of the upper
airway during sleep are two major characteristics of OSA, resulting in
intermittent hypoxia (IH) and sleep fragmentation. IH correlates with
systemic/airway inflammation and oxidative stress.\textsuperscript{3}The
treatments of OSA include continuous positive airway pressure (CPAP) or
surgery. Uvulopalatopharyngoplasty (UPPP) was first suggested by Fujita
et al.\textsuperscript{4} If the obstruction site of OSA is located at
the palatopharyngeal level, UPPP usually achieve an ideal outcome by
eliminating redundant mucosal folds, hypertrophic tonsils and the
excessively thickened and elongated soft palate.

Laryngeal mucosal inflammation and damage of laryngopharyngeal re\selectlanguage{english}flux
(LPR) occurs when gastric acid flow back to the laryngopharynx, and is a
common disease in otolaryngology\textsuperscript{5}. Although 24-hour pH
monitoring is the gold standard for diagnosing the presence of LPR,
Re\selectlanguage{english}flux Symptom Index (RSI) and Reflux Finding Score (RFS) are more
commonly used and useful in diagnosing LPR and quantifying the severity
of LPR symptoms.\textsuperscript{5, 6}

Chronic upper airway inflammation is the result of many conditions,
among which OSA and LPR are two reasons that cannot be ignored. The
presence of LPR in OSA is very frequent: 20\%--67\% OSA patients coexist
with LPR.\textsuperscript{7} In recent years, many studies have explored
the association between OSA and LPR, but the correlation between them is
still controversial. Some studies demonstrated that CPAP treatment
significantly improved reflux symptoms in OSA
patients.\textsuperscript{8} But few studies have been done about the
effect of surgery treatment for OSA on reflux disease. The aim of this
study was to evaluate the change in laryngeal reflux symptoms and signs
after UPPP for OSA, based on patients' responses to the RSI and RFS
questionnaire.

\textbf{Methods}

\textbf{Procedure and participants}

Adult participants were recruited between January 2016 to January 2017.
Only male included to minimize gender confounder variance, particularly
considering that OSA is more common in males. Of all 128 participants,
17 (13\%) declined to participate and 20 (16\%) were found to be
ineligible (female, with CPAP or anti-reflux treatment) leaving 91
(71\%) for the present study.~The study included cases with newly
diagnosed OSA (confirmed by PSG). Controls were selected without OSA
(confirmed by PSG). Participants from OSA were eligible for LPR if both
RSI score \textgreater{}13 and RFS score \textgreater{}7. The study
design has been described in \textbf{Figure 1} .

\textbf{Approval by the Human Research Ethics Committee}

The study was approved by the ethics committee of \textless{}Blinded for
review\textgreater{}, and all participants gave written informed
consent.

\textbf{Assessment of OSA}

All individuals with clinical suspicion underwent overnight
polysomnography (PSG). They were asked if they had a specific set of
symptoms indicating OSA: witnessed snoring; observed to have apneas;
non-restful sleep; daytime sleepiness. Diagnosis of OSA was defined by
standard criteria.\textsuperscript{9}

The Epworth Sleepiness Scale (ESS) questionnaire, which is widely used
for assessing daytime sleepiness, was also finished by the patients on
the same visit. Demographic data including gender, age, BMI, AHI,
minimum oxygen saturation and oxygen saturation \textless{}90\% were
also obtained.

\textbf{Assessment of LPR}

LPR was defined as both RSI score \textgreater{}13 and RFS score
\textgreater{}7.

During the initial visit, all the patients filled out RSI questionnaire
to evaluate the severity of LPR-related symptoms, which containing
9-item and 0-5 score: the higher the score, the more serious the
problem.

The RFS \textsuperscript{5} is a useful tool to assess and follow-up LPR
patients, which contains 8 items for judging severity of laryngoscopic
findings. The laryngoscopy were reviewed by an otolaryngologist blinded
to patient RSI and PSG information. They rated 8 items from 0 (normal)
to 4 (severe problem) according to laryngoscopic findings.

\textbf{UPPP surgery}

UPPP significantly relieve airway obstruction at palate level. The
individuals who underwent UPPP surgery must meet the following inclusion
criteria: (1)Suffered from OSA and without serious psychiatric,
cardiopulmonary, or neurological disease; (2)overnight PSG indicating
AHI \selectlanguage{english}[?] 5 and BMI\selectlanguage{english}<40kg/m\textsuperscript{2}; (3) Thickened and elongated
soft palate and without severe nasal congestion; (4) Friedman stage \selectlanguage{english}I or
\selectlanguage{english}II; (5) Unsuccessful CPAP treatment or reject CPAP treatment. Individuals
and (6) No history of surgical therapy for OSA or anti-reflux treatment
before or after surgery. Surgeon (LSS) performed UPPP surgery all the
time. The successful UPPP was defined as post-operative AHI is reduced
by at least 50\% and \selectlanguage{english}<20/h.\textsuperscript{10}

\textbf{Follow-up}

All individuals were re-evaluated in our sleep disorder center during
follow-up visits after 6 months of UPPP surgery. Polysomnography, RSI
questionnaire and ESS questionnaire were obtained from each patient. The
investigator (LSS) was not involved in the care of any of the patients.

\textbf{Statistical analysis}

Chi-square or Mann-Whitney U was used in different type of variables,
and regression analysis was performed to show effect of different
variables on outcome data by statistical analysis system (version 24.0;
SPPS Inc., Chicago, IL). Significant was defined as \emph{p}value\selectlanguage{english}<0.05.

\textbf{Results}

\textbf{Population characteristics}

The initial characteristics of 64 OSA cases (AHI\selectlanguage{english}[?]5 events/h) and 27
controls are presented in \textbf{Table 1} . No significant changes were
found between the OSA and control group in sex (all male) age and BMI.
Individuals with OSA had more AHI and lower nighttime SpO2 (CT90 and
L-SpO2) in PSG. As anticipated, RSI and RFS score of OSA patients were
higher than the controls.

\textbf{Relationship between OSA and LPR}

In 64 OSA patients, AHI and CT90 have a positive correlation with RSI
and RFS, which means the degree of OSA is associated with the severity
of LPR \textbf{(Figure 2A, 2B)} . L-SpO2 negatively correlate with RSI
and RFS \textbf{(Figure 2C)} . In addition, RSI and RFS scores of severe
OSA were higher than mild to moderate OSA patients, so as the prevalence
of LPR (\textbf{Table 2} ).

\textbf{Surgical outcome}

\textbf{Table 3} showed post-operative AHI, nighttime SpO2 (CT90 and
L-SpO2) and ESS decreased, among 34 OSA patients after UPPP surgery.
What's more, both RSI and RFS decreased after treatment for OSA.

The surgical success rate was 73.53\% (25/34). In 25 successful-surgery
patients, RSI and RFS were downward after surgery, and the prevalence of
LPR changed just after successful UPPP surgery (\textbf{Table 4} ).

\textbf{Figure 3}showed except for hoarseness (P=0.054), all individual
variables of postoperative RSI significantly improved (\emph{P}
\textless{}0.05). When we compared the pre- and post-surgery changes in
individual variables of RSI to patients in successful or unsuccessful
surgeries group, all variables of successful-postoperative RSI improved
(\emph{P} \textless{}0.05) except hoarseness and postnasal drip
(\emph{P} =0.117 and \emph{P} =0.052, respectively), but all variables
in the RSI showed no significantly changes after unsuccessful surgery.



\textbf{Discussion}

This study investigated the effect of UPPP surgery for OSA on laryngeal
reflux symptoms based on patient responses to the RSI and RFS
questionnaire. We found (1) a close correlation between OSA and LPR: LPR
are more prevalent in OSA patients than the general population and the
degree of AHI and CT90 were positively and L-SpO2 negatively related
with LPR symptoms. (2) UPPP surgery, especially successful surgery
significantly lowered not only in terms of the mean RSI and mean RFS
scores but also individual variables of RSI.

The coexistence of OSA with LPR has been reported to have a prevalence
of 20\%--67\%.\textsuperscript{11, 12} Although previous studies were
unable to demonstrate a direct relationship between OSA and LPR, they
did suggest a possible causative relationship between
them.\textsuperscript{13} Our study indicated OSA patients had higher
RSI and RFS than non-OSA patients. RSI and RFS of severe OSA patients
were higher than mild to moderate OSA. The degree of AHI and CT90 were
positively and L-SpO2 negatively related with LPR symptoms. All these
means the degree of OSA is associated with the severity of LPR and there
is a close correlation between OSA and LPR. Interreaction of OSA and LPR
can explain our results. OSA causes inflammatory injury, low
intrathoracic pressure and leakage of lower esophageal sphincter; in
turn, LPR (Acid reflux) results in esophagus, larynx, and pharynx
mucosal injury and laryngopharyngeal symptoms.

Some studies report that anti-reflux therapy on OSA patients improve the
symptoms and PSG parameters of OSA.\textsuperscript{14} At the same
time, other studies report that CPAP can reduce GER events and improve
nocturnal GER symptoms in OSA patients.\textsuperscript{10, 11} But few
studies have reported the effect of OSA surgery on
LPR.\textsuperscript{15} UPPP is not the first choice of treatment in
most OSA patients compared to~CPAP. If CPAP is refused or obstructive
plane is definite, surgery can be considered for OSA, especially
multilevel surgery. UPPP can achieve favorable result when airway
obstruction only at the level behind palate, and our study included
participants whose block~plane~in~the oropharynx. The present study
demonstrated post-operative AHI, nighttime SpO2 (CT90 and L-SpO2), RSI
and RFS got a great improvement. Interestingly, the mean postoperative
RSI and RFS in successful surgery group showed significant decrease, but
there just one significant difference (mean RFS) occurred in
unsuccessful group. We proposed successful UPPP surgery lowered RSI and
RFS scores; unsuccessful surgery just improved RFS.

In the study, we supposed that effective UPPP could improve LPR symptoms
and signs via three ways. Firstly, UPPP solves the problem of
OSA-induced inflammatory injury via reducing airflow obstruction and
increasing nocturnal blood oxygen saturation. Published studies have
proposed that mouth breathing and snoring aggravates pharyngeal
inflammation and LPR, and chronic intermittent hypoxia can lead to
systemic inflammation of the~whole~body and respiratory in
OSA.\textsuperscript{16-18} Secondly, successful UPPP lowers OSA-induced
esophageal change. It has been postulated that OSA causing lowering
intrathoracic pressure and leakage of lower esophageal
sphincter\textsuperscript{19}: (1) when either apneas or hypopnea occur,
OSA patient overcome the hypoxia by sleep breathing effort, which
produce high transdiaphragmatic pressure and low intrathoracic pressure,
exacerbating the lower esophageal sphincter(LES) pressure gradient and
favoring acid reflux into esophagus, resulting in laryngeal mucosal
injury.\textsuperscript{20-22} (2) the inflammation that goes with OSA
may make the patient prone to dysphagia by hypoxia-reoxygenation,
promoting narrow the upper airway.\textsuperscript{17} Additionally,
some studies have found that hypoxia inducible factor(HIF)-2\selectlanguage{greek}α \selectlanguage{english}may play
an important role in reflux esophagitis, indicating that nocturnal low
oxygen saturation may aggravate LPR symptoms.\textsuperscript{23} (3)
the OSA-induced airway~resistance cause reflux events coexisting
transient LES pressure relaxation.\textsuperscript{24, 25} Thirdly,
LPR-induced inflammation cannot be ignored in the cycle between OSA and
LPR. Previous studies have proposed that LPR results in esophagus,
larynx, and pharynx mucosal injury and laryngopharyngeal symptoms, which
promote: (1) tissue thickening and hypertrophy caused by chronic
inflammation can directly cause narrow upper airway and (2) increased
sensitivity of the laryngopharyngeal mucosa, inflammation-mediated
tissue damage and sensory impairment contribute to upper respiratory
collapse.\textsuperscript{13} UPPP improves LPR in two aspects mentioned
above, which break the cycle between OSA and LPR.

Patients often have postoperative complaints after UPPP surgery,
including pharyngeal pain, swallowing difficulty and lump sensation.
Most symptoms are the same as listed on the RSI questionnaire and might
result from scarification of surgical wound. But our study found most
symptoms improved after UPPP. This unexpected finding
likely~benefited~from UPPP which removes the upper airway obstruction.

Our study has limitations. Firstly, a more objective and easy measure to
evaluate the effects of UPPP to LPR is needed to clarify our results and
evaluate obstruction level. There are several reasons we chose RSI and
RFS instead of 24-hour pH monitoring to diagnose LPR and evaluate the
effect of UPPP. First of all, RSI and RFS are not only easy to operate
for both patients and doctors, but also convenient for follow-up.
Secondly, 24-hour pH monitoring is difficult for patients to accept
leading to poor adherence. In addition, further~discussion was focused
on subjective sensation of upper respiratory tract after UPPP surgery.
Secondly, OSA patients often complain similar symptoms (lump sensation,
throat-clearing, difficulty swallowing) listed in the RSI questionnaire
after surgery treatment, which are difficult to tell apart. Further
study need compare every OSA patient pre-operative and post-operative
changes of each items in RSI and RFS questionnaires. Thirdly, UPPP can
solve IH or upper airway resistance of OSA. Future study with more cases
is needed to explore whether IH or upper airway resistance improve LPR.

\textbf{Conclusion}

In summary, LPR symptoms are prevalent in OSA patients, the coexistence
of OSA and LPR cannot be ignored. Successful UPPP surgery as a treatment
for OSA patients, potentially reduces laryngeal reflux symptoms and
improves laryngoscope signs by alleviating sleep respiratory disorder.

\textbf{Data Availability Statement}

The data supporting the findings of this study are available with
request of the corresponding author.

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Table 1 Initial characteristics of participants\selectlanguage{english}
\begin{longtable}[]{@{}llll@{}}
\toprule
Characteristic & Controls (n=27) & OSA(n=64) & \emph{P}
value\tabularnewline
\midrule
\endhead
Age (years) & 43.85\selectlanguage{ngerman}±10.95 & 42.98\selectlanguage{ngerman}±10.21 & 0.718\tabularnewline
BMI (kg/m2) & 26.73\selectlanguage{ngerman}±3.74 & 27.19\selectlanguage{ngerman}±3.46 & 0.576\tabularnewline
AHI (events/h) & 3.00\selectlanguage{ngerman}±1.20 & 34.62\selectlanguage{ngerman}±14.8 & \textless{}0.05\tabularnewline
ESS & 4.33\selectlanguage{ngerman}±1.88 & 11.31\selectlanguage{ngerman}±6.14 & \textless{}0.05\tabularnewline
L-SpO2 (\%) & 85.78\selectlanguage{ngerman}±3.70 & 70.16\selectlanguage{ngerman}±11.09 & \textless{}0.05\tabularnewline
CT90 (\%) & 1.14\selectlanguage{ngerman}±1.51 & 29.29\selectlanguage{ngerman}±21.75 & \textless{}0.05\tabularnewline
RSI & 7.59\selectlanguage{ngerman}±4.70 & 13.70\selectlanguage{ngerman}±5.56 & \textless{}0.05\tabularnewline
\textgreater{}13 & n=6 & n=33 & \textless{}0.05\tabularnewline
[?]13 & n=21 & n=31 &\tabularnewline
RFS & 6.04\selectlanguage{ngerman}±3.55 & 10.45\selectlanguage{ngerman}±5.03 & \textless{}0.05\tabularnewline
\textgreater{}7 & n=8 & n=43 & \textless{}0.05\tabularnewline
[?]7 & n=19 & n=21 &\tabularnewline
\bottomrule
\end{longtable}

Data are presented as median \selectlanguage{ngerman}± SD. BMI: body mass index, AHI:
apnea/hypopnea index, ESS: Epworth Sleepiness Scale (range 0-24),
L-SpO2: lowest blood oxygen saturation during recording time, CT90\%:
percentage of recording time when oxygen saturation of arterial
blood\textless{}90\%, RSI: reflux symptom index, RFS: reflux finding
score.

\textbf{Table 2} Reflux symptom index and reflux finding score between
mild-moderate OSA and severe OSA patients before UPPP\selectlanguage{english}
\begin{longtable}[]{@{}llll@{}}
\toprule
\begin{minipage}[b]{0.24\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[b]{0.24\columnwidth}\raggedright\strut
Mild-moderate OSA (n=29)\strut
\end{minipage} & \begin{minipage}[b]{0.24\columnwidth}\raggedright\strut
Severe OSA (n=35)\strut
\end{minipage} & \begin{minipage}[b]{0.24\columnwidth}\raggedright\strut
\emph{P} value\strut
\end{minipage}\tabularnewline
\midrule
\endhead
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
RSI\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
11.34\selectlanguage{ngerman}±5.40\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
15.66\selectlanguage{ngerman}±4.96\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
<0.05\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\textgreater{}13\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
n=9\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
n=24\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
<0.05\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
[?]13\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
n=20\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
n=11\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
RFS\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
7.07\selectlanguage{ngerman}±2.78\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
13.26\selectlanguage{ngerman}±4.75\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
<0.05\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\textgreater{}7\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
n=14\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
n=29\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
<0.05\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
[?]7\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
n=15\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
n=6\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\strut
\end{minipage}\tabularnewline
\bottomrule
\end{longtable}

Data are presented as median \selectlanguage{ngerman}± SD. RSI: reflux symptom index, RFS:
reflux finding score.

\textbf{Table 3} Various factors before and after UPPP surgery\selectlanguage{english}
\begin{longtable}[]{@{}llll@{}}
\toprule
Characteristic & Before Surgery & After Surgery & \emph{P}
value\tabularnewline
\midrule
\endhead
BMI (kg/m2) & 27.33\selectlanguage{ngerman}±3.98 & 26.64\selectlanguage{ngerman}±3.45 & 0.370\tabularnewline
AHI (events/h) & 46.73\selectlanguage{ngerman}±8.00 & 19.94\selectlanguage{ngerman}±11.30 & <0.05\tabularnewline
ESS & 15.15\selectlanguage{ngerman}±5.29 & 9.59\selectlanguage{ngerman}±3.89 & <0.05\tabularnewline
L-SpO2 (\%) & 65.56\selectlanguage{ngerman}±10.16 & 81.28\selectlanguage{ngerman}±7.22 & <0.05\tabularnewline
CT90 (\%) & 38.18\selectlanguage{ngerman}±19.70 & 11.65\selectlanguage{ngerman}±13.80 & <0.05\tabularnewline
RSI & 15.88\selectlanguage{ngerman}±4.85 & 9.53\selectlanguage{ngerman}±4.16 & <0.05\tabularnewline
\textgreater{}13 & n=24 & n=6 & <0.05\tabularnewline
[?]13 & n=10 & n=28 &\tabularnewline
RFS & 13.18\selectlanguage{ngerman}±4.80 & 8.65\selectlanguage{ngerman}±4.87 & <0.05\tabularnewline
\textgreater{}7 & n=28 & n=11 & <0.05\tabularnewline
[?]7 & n=6 & n=23 &\tabularnewline
\bottomrule
\end{longtable}

Data are presented as median \selectlanguage{ngerman}± SD. BMI: body mass index, AHI:
apnea/hypopnea index, ESS: Epworth Sleepiness Scale (range 0-24),
L-SpO2: lowest blood oxygen saturation during recording time, CT90\%:
percentage of recording time when oxygen saturation of arterial
blood\textless{}90\%, RSI: reflux symptom index, RFS: reflux finding
score.

Table 4 Changes between re\selectlanguage{english}flux symptom index and reflux finding score in
patients with UPPP surgery\selectlanguage{english}
\begin{longtable}[]{@{}llllllll@{}}
\toprule
& Successful(n=25) & Successful(n=25) & Successful(n=25) &
\emph{P} value & Unsuccessful (n=9) & Unsuccessful (n=9) & \emph{P}
value\tabularnewline
\midrule
\endhead
& Before Surgery & After Surgery & & & Before Surgery & After Surgery
&\tabularnewline
RSI & 16.04\selectlanguage{ngerman}±4.48 & 8.60\selectlanguage{ngerman}±3.50 & \textless{}0.05 & \textless{}0.05 &
15.44\selectlanguage{ngerman}±6.06 & 12.11\selectlanguage{ngerman}±4.94 & \textless{}0.05\tabularnewline
\textgreater{}13 & n=18 & n=3 & \textless{}0.05 & \textless{}0.05 & n=6
& n=3 & 0.347\tabularnewline
[?]13 & n=7 & n=22 & & & n=3 & n=6 &\tabularnewline
RFS & 13.44\selectlanguage{ngerman}±4.87 & 7.92\selectlanguage{ngerman}±4.52 & \textless{}0.05 & \textless{}0.05 &
12.44\selectlanguage{ngerman}±4.80 & 10.67\selectlanguage{ngerman}±5.52 & 0.150\tabularnewline
\textgreater{}7 & n=22 & n=7 & \textless{}0.05 & \textless{}0.05 & n=6 &
n=4 & 0.341\tabularnewline
[?]7 & n=3 & n=18 & & & n=3 & n=5 &\tabularnewline
\bottomrule
\end{longtable}

Data are presented as median \selectlanguage{ngerman}± SD. RSI: reflux symptom index, RFS:
reflux finding score.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image1/image1}

\end{center}
\end{figure}

Figure 1 Flow diagram of participates. AHI: apnea hypopnea index; CPAP:
continuous positive airway pressure; PSG: polysomnography; RSI: reflux
symptom index, RFS: reflux finding score; UPPP:
uvulopalatopharyngoplasty surgery.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image2/image2}

\end{center}
\end{figure}

Figure 2 Correlation of LPR and sleep parameters. RSI and RSF scores
were positively correlated with AHI (A) and CT90 (B), and negatively
correlated with L-SpO2(C). RSI: reflux symptom index, RFS: reflux
finding score. AHI: apnea hypopnea index; CT90: percentage of recording
time when oxygen saturation of arterial blood\textless{}90\%; L-SpO2:
lowest SpO2 during sleep.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image3/image3}

\end{center}
\end{figure}

Figure 3 Reflux symptom index scores before and after UPPP surgery in
different groups. (A) All individual variables (except hoarseness) in
the RSI improved significantly after surgery. Except hoarseness and
postnasal drip, all variables in the RSI improved significantly after
successful surgery (B), but all variables in the RSI showed no
significantly changes after unsuccessful surgery (C). * ? \textless{}
0.05 compared with before UPPP group.

\selectlanguage{english}
\FloatBarrier
\end{document}

