2017 Sec 1 Green Book

studies have evaluated the effect of LT on persistent

OSA in patients with DS. In light of these findings, it

was our goal to evaluate the polysomnographic success

of LT to resolve persistent pediatric OSA in our patients

with DS.

MATERIALS AND METHODS

Following institutional review board approval at the Cin-

cinnati Children’s Hospital Medical Center, we performed a ret-

rospective chart review of patients with DS who were age 18

years and younger who underwent LT using radiofrequency

ablation

from 2003 to 2013. All patients had previously under-

gone a T&A and were diagnosed with lingual tonsil hypertrophy

using dynamic upper airway cine magnetic resonance imaging

(MRI). Patients who completed polysomnography (PSG) before

and after LT were included. Patients who did not have both

pre- and postoperative PSGs or those whose preoperative

obstructive apnea-hypopnea index (oAHI) was

1 event/hour,

were excluded.

Charts were reviewed for demographic data and PSG out-

comes including the apnea-hypopnea index (AHI), oAHI, O

nadir, percent of total sleep time that was rapid eye movement

(REM) sleep, percent of sleep study time with CO

50 mm Hg,

obstructive apnea index, hypopnea index, maximum end tidal

, and central apnea index.

PSG Recording

PSG was performed with Grass System (Grass Telefactor,

West Warwick, RI) for up to 12 hours in a quiet dark room with

an ambient temperature of 24

C, in the company of their

parents. The standard pediatric montage was used. The follow-

ing parameters were recorded simultaneously: body position,

bilateral electro-occulogram, six-channel electroencephalogram

(F3M2, F4M1, C3M2, C4M1, O1M2, O2M1), chin electromyo-

gram, anterior tibialis electromyogram, tracheal microphone,

electrocardiogram, pulse oximetry (Masimo, Irvine CA), thoracic

and abdominal inductance plethysmography, nasal pressure

transducer (Pro-Tech, Mukilteo, WA), and end-tidal CO

(BCI,

Capnochecks; Smiths Medical, St. Paul, MN). Studies were

interpreted by board-certified pediatric sleep medicine physi-

cians at Cincinnati Children’s Hospital Medical Center.

PSG Interpretation

All polysomnographs were scored according to the Ameri-

can Academy of Sleep Medicine (AASM) guidelines.

An apnea

was defined as a reduction of airflow of

90% for at least two

breathing cycles. Apneas were identified as obstructive when

associated with continued or increased respiratory effort. A

mixed apnea was identified when absence of airflow was associ-

ated with periods with and without respiratory effort. A hypo-

pnea was defined as a decrease in airflow of 50% for at least

two breathing cycles followed by a 3% decrease in oxygen sat-

uration or an electrocortical arousal from sleep. The obstructive

apnea index was calculated as the number of obstructive and

mixed apneas divided by the total sleep time. The hypopnea

index was calculated as the number of obstructive hypopneas

divided by the total sleep time. The AHI was calculated as the

number of apneas and hypopneas, divided by the total sleep

time. The oAHI was calculated as the sum of the obstructive

apneas, mixed apneas, and hypopneas, divided by the total

sleep time. Severity of OSA was defined by oAHI. Mild OSA

was defined as 1 to

5 events per hour, moderate OSA was

defined as 5 to

10 events per hour, and severe OSA was

defined as 10 events per hour. The saturation nadir was

defined as the lowest oxygen saturation reading during a respi-

ratory event.

Statistical Analysis

Data distributions were reported as means with standard

deviations in parentheses and medians with minimum and

maximum values in brackets. Due to the fact that the data did

not follow a normal distribution, nonparametric statistical anal-

yses were conducted to test postsurgery changes. Changes in

measurements pre- and postsurgery were tested using the Wil-

coxon signed rank test for continuous variables; changes in cat-

egorical variables were tested using the McNemar test.

RESULTS

Forty patients with DS underwent LT, and 21 met

the inclusion criteria. The demographics for this study

population are displayed in Table I. The mean age at

surgery was 9.3

4.3 years (47.6% were female and

90.5% were white). Individual patient PSG data can be

found in the Supporting Information, Appendix 1A and

1B, in the online version of this article. The median AHI

was 9.1 events/hour (range, 3.8 to 43.8 events/hour)

before surgery and 3.7 (range, 0.5 to 24.4 events/hour)

after surgery (Table II). The median improvement in

overall AHI and the oAHI were 5.1 events/hour (range,

2.9 to 41 events/hour) and 5.3 events/hour (range,

2.9 to 41 events/hour), respectively (

.0001). The

mean oxygen saturation nadir improved from 84% to

89% (

.004); however, there were no significant

changes in the mean percent time with CO

50 mm

Hg, central index, or percentage of REM sleep. After

surgery, the oAHI was

5 events/hour in 61.9% of

patients and 1 event/hour in 19%. After LT, 28.5% of

patients had moderate OSA, and 14% had severe OSA,

as measured by the oAHI. Stratification of patients by

age did not affect the PSG outcomes (Table III). Further

TABLE I.

Study Population Demographics for Children With Down

Syndrome Who Underwent Lingual Tonsillectomy for Obstructive

Sleep Apnea After Adenotonsillectomy.

Characteristic

Demographics,

Age at preoperative PSG, yr,

mean (SD), median [range]

8.9 (4.4),

7.8 [3.6–16.9]

Age at surgery, yr, mean (SD),

median [range]

9.3 (4.3),

8.1 [4.4–17.2]

Age at postoperative PSG, yr,

mean (SD), median [range]

9.7 (4.3),

8.6 [4.6–17.4]

Age at surgery

3–6 years, n (%)

7 (33.3%)

6 years, n (%)

14 (66.7%)

Race, white, n (%)

19 (90.5%)

Sex, male, n (%)

11 (52.4%)

BMI percentile, n

13,

mean (SD), median [range]

82.8 (27.4),

92 [1–99]

Mean and median values are reported.

BMI

body mass index; PSG

polysomnography; SD

standard

deviation.

Prosser et al.: PSG Outcomes of Lingual Tonsillectomy in DS