Rhinological and Otological Society, Inc.
C 2011 The American Laryngological,
Improved Growth Curve Measurements After Supraglottoplasty
Jeremy D. Meier, MD; Shaun A. Nguyen, MD; David R. White, MD
Objectives/Hypothesis: To evaluate changes in growth curve measurements after supraglottoplasty and compare these
patterns to patients with laryngomalacia treated conservatively.
Study Design: Retrospective case–control study.
Methods: Children treated surgically for laryngomalacia were compared to control groups of patients who underwent
observation or medical treatment only. Body weight the day of surgery and on follow-up visits was plotted on a standardized
growth curve and the z-score calculated.
Results: A total of 15 patients were included that were observed (group 1), 71 patients that were treated with medical
therapy only (group 2), and 29 patients that underwent surgery (group 3). The average z-score at the time of surgery was
significantly worse in group 3 (?0.854 6 1.080), compared to the z-score at the time of diagnosis in group 1 (?0.086 6
0.834), and the time when antireflux therapy was initiated in group 2 (?0.120 6 0.979). Within 3 months from surgery, sig-
nificant improvement on the growth curve was seen in group 3 (P ¼ .009). After 12 months, all three groups approached the
mean on the growth curve.
Conclusions: In this series, patients with severe laryngomalacia who warranted surgery presented with significantly
lower percentile weight on a standardized growth curve than patients who required only medical or conservative treatment.
Substantial improvement in growth curve percentile was seen in the immediate months following supraglottoplasty. Long-
term follow-up after supraglottoplasty shows that infants return to a mean weight on the growth curve.
Key Words: Laryngomalacia, supraglottoplasty, growth curve.
Level of Evidence: 3b.
Laryngoscope, 121:1574–1577, 2011
Laryngomalacia is the most common congenital ab-
normality of the larynx and the most common cause of
stridor in infants.1The stridor attributed to laryngoma-
lacia is typically inspiratory and worsens when the child
is supine or agitated. Prolapse of the supraglottic struc-
tures into the laryngeal inlet during inspiration causes
noisy breathing that can often be frightening to the new
parent and cause feeding difficulty, obstructive sleep
apnea, and respiratory distress in the infant.
A number of factors are believed to play a role in
the development of laryngomalacia, but the precise etiol-
ogy is not completely understood. Anatomically, an
omega shaped epiglottis, shortened aryepiglottic folds,
and redundant mucosa overlying the arytenoids is typi-
cally seen. Abnormal laryngeal neurodevelopment2and
gastroesophageal reflux3have also been implicated in
the etiology of laryngomalacia.
Most infants with laryngomalacia can be managed
conservatively with observation or antireflux medication.
The majority of cases will resolve spontaneously by 1
year of age.4More severe cases are treated surgically.
Surgical indications for laryngomalacia vary among
surgeons but generally include severe stridor with respi-
ratory difficulties or feeding problems and failure to
Surgery for laryngomalacia typically involves some
form of supraglottoplasty with division of the aryepiglot-
tic folds and resection of supraglottic tissue. High success
rates have been seen in many studies.6–15Unfortunately,
most of these series use subjective outcomes such as
improvement in stridor or resolution of feeding difficul-
ties to measure success. Objective measures such as the
need for revision supraglottoplasty or tracheostomy are
discussed, but the significance is limited by the low inci-
dence of failure requiring these additional operations.
objectively using polysomnography.16In another series,
outcomes after laser epiglottopexy for laryngomalacia
The purpose of this study is to evaluate changes in
growth curve measurements after supraglottoplasty in
children with laryngomalacia and compare these results
to patients with laryngomalacia treated conservatively
with observation or medical therapy. If growth curve
measurements were determined to be a reliable indicator
of successful results, these parameters could be used in
future outcome-based studies.
From the Department of Otolaryngology—Head and Neck Surgery,
Medical University of South Carolina, Charleston, South Carolina, U.S.A.
Editor’s Note: This Manuscript was accepted for publication April
This article was presented at the Society for Ear Nose and Throat
Advances in Children (SENTAC), Cincinnati, OH, December 3–5, 2010.
The authors have no financial disclosures for this article.
The authors have no conflicts of interest to disclose.
Send correspondence to Jeremy D. Meier, Department of Otolar-
yngology—Head and Neck Surgery, Medical University of South Caro-
lina, 135 Rutledge Avenue, MSC 550, Charleston, SC 29425.
Laryngoscope 121: July 2011Meier et al.: Growth Curve Changes after Supraglottoplasty
MATERIALS AND METHODS
Approval by the institutional review board at the Medical
University of South Carolina was obtained prior to this retro-
spective review. Clinic and hospital notes were reviewed in all
patients evaluated by the otolaryngology service at the Medical
University of South Carolina with an ICD-9 diagnosis of 748.3
(other congenital anomalies of larynx, trachea, and bronchus)
from June 2003 through January 2010. Patients with gastros-
abnormalities, greater than 2 years of age, or severe develop-
mental delay were excluded, and only patients with confirmed
laryngomalacia during chart review were included. Patients
were stratified into three groups: 1) observation only, 2) medical
therapy (H2blocker and/or proton pump inhibitor) without sur-
gery, or 3) surgery with or without medical therapy.
The endoscopic operation was performed by three different
surgeons and consistedof
modifications based on surgeon preference. The typical supra-
glottoplasty performed at this institution involves incising the
aryepiglottic folds and excising redundant tissue overlying the
arytenoid cartilage. Most operations were performed using cold
steel microlaryngeal instruments, although three surgeries
were performed using the CO2laser.
Body weight at the initial visit (group 1), the initiation of
medical therapy (group 2), or the day of surgery (group 3) was
recorded and defined as T0. All available follow-up weights
were recorded and the time from T0was calculated. Data points
were then determined at 3 (T3), 6 (T6), 9 (T9), and 12 (T12)
months from T0by taking the last available weight within each
of these time points. Age and gender specific weight percentile
and z-score was calculated for each data point based on the for-
mula used by the National Health and Nutrition Examination
All analyses and graphs were performed with
Sigma Stat 3.5 and Sigma Plot 10.0 (SPSS, Chicago, IL).
In general, summary statistics consisted of the following:
categorical variables: N (number of patients of statistical
analysis set) and percentage; continuous variables: N,n
(number of nonmissing observations), mean, standard
deviation, minimum, median, and maximum.
Mean age (in months) at T0was compared among
the three groups using Analysis of Variance (ANOVA).
ANOVAs were also used to compare the mean z-scores
for all three groups at T0, T3, and T>6 months. In addition,
further analysis was done by using Duncan’s post hoc
analysis to establish significant differences in z-score
among the three groups at T0, T3, and T>6 months. A P-
value of .05 or less was considered to indicate a statisti-
cally significant difference for all tests.
A total of 426 patients were identified with an ICD-
9 diagnosis of 748.3. Laryngomalacia was confirmed in
308 patients, of which 64 underwent supraglottoplasty.
After applying the exclusion criteria, 67 patients (22%)
were excluded. A total of 126 patients (41%) could not be
included in the analysis due to incomplete medical
records. The remaining 115 patients (37%) had both pre-
treatment and posttreatment weights recorded. The
number of patients, gender, and age at T0for each group
is provided in Table I. Significantly fewer females were
found in the observation group compared to the other
two groups (P ¼ .0285). No significant difference in
patient age at T0was noted between the groups. Average
follow-up for all patients was 9.2 6 7.1 months. The av-
erage z-score at T0was significantly worse in group 3 at
?0.854 6 1.080, compared to group 1 at ?0.086 6 0.834
and group 2 at ?0.120 6 0.979 (Fig. 1, P ¼ .003).
At the latest follow-up data available within 3
months from T0, significant improvement on the growth
curve was seen in Group 3. The average z-score improved
from ?0.854 6 1.080 (N ¼ 29) to ?0.322 6 1.604 (N ¼
25), P ¼ .009. The average z-score at T3was no longer
statistically significant between the three groups.
Long-term follow-up was considered follow-up longer
than 6 months. Figure 2 depicts the average z-score val-
ues at T0, T3, and the longest follow-up in patients with
data available more than 6 months after T0. Average z-
scores at T0, T3, T6, and T12are plotted in Figure 3.
Indications for supraglottoplasty include severe stri-
dor, respiratory distress, and feeding difficulties with
accompanying failure to thrive. The criteria for supra-
glottoplasty are not etched in stone and can vary
between surgeons. Regardless, reported outcomes for
supraglottoplasty are generally excellent.6–15Unfortu-
nately, many studies use subjective outcomes such as
Age, Gender, and Number of Patients in Each Study Group.
Group 1 (Observation)1527% 2.96 6 2.78
2.26 6 1.63
3.93 6 4.67
Group 2 (Medical Therapy ) 7151%
Group 3 (Surgery)29 41%
T0is defined as the age at the initial visit for Group 1 patients, the
age at initiation of medical therapy for Group 2 patients, or the age at the
time of surgery for Group 3 patients.
Fig. 1. Average z-score at T0for the observation, medical treat-
ment, and surgical groups. Average z-score is significantly lower
in the surgical treated group than the other two groups (P ¼.003).
Laryngoscope 121: July 2011Meier et al.: Growth Curve Changes after Supraglottoplasty
resolution of stridor or improved feeding to determine
results. Objective measures such as the need for revision
surgery or tracheotomy can be used, but the incidence of
these additional procedures is low and makes distin-
guishing differences in effectiveness challenging.
A recent study evaluated the effectiveness of laser
epiglottopexy using weight percentiles and remains the
only other published report to our knowledge detailing
postoperative changes in growth percentiles after sur-
gery for laryngomalacia.17Our findings support the
results described in that paper showing a ‘‘catch-up’’
growth phase postoperatively in the surgically treated
patients. This phenomenon occurred more rapidly than
we would have predicted, as the average z-score differ-
ence was no longer statistically significant from the
observation and medically treated groups less than 3
months following supraglottoplasty. Additionally, many
of the supraglottoplasty patients had previously failed a
trial of observation or antireflux therapy, making the
changes following surgical
Our study is the first to compare growth curve
measurements between laryngomalacia patients treated
surgically and those treated with expectant observation
or antireflux medication. Although the surgical group
began significantly lower on the growth curve than the
control groups, 12 months after the initiation of therapy
all three groups approached the mean on the growth
curve. One wonders where the supraglottoplasty group
would lie on the growth curve at 12 months if no opera-
tion had been performed, especially because many of
these patients had been managed for a few months with
observation or medical management. As evidenced by
the ‘‘catch-up’’ growth phase, it appears many of these
patients benefited significantly from the supraglotto-
plasty. Explanations for the accelerated growth could
include improved efficiency of feeding once the airway
was improved as well as decreased caloric consumption
with resolution of the airway obstruction. Additionally,
hormonal abnormalities have been noted in older chil-
dren with obstructive sleep apnea. Serum levels of
insulin-like growth factor-I (IGF-I) and insulin-like
growth factor binding protein-3 (IGFBP-3) significantly
increased after adenotonsillectomy in these patients.19It
is possible that similar abnormalities exist in infants
with obstructive sleep apnea and chronic obstruction
from laryngomalacia. The long-term effects of this per-
ceived growth deprivation in the early neonatal period
are unknown and warrant further investigation.
This study had several limitations, most notably
the retrospective method of data collection. A significant
number of patients could not be included in the study
because follow-up data was not available. However, the
authors predict that many of those patients had unavail-
able follow-up data because they significantly improved
after intervention and sought follow-up care in their
local community. Although we cannot assume the results
of those lost to follow-up, it is unlikely that a significant
number failed therapy and continued to struggle without
To limit confounding factors and better compare the
growth curves between
patients, children with significant comorbidities and risk
factors for treatment failure were excluded. Because of
these exclusions, the surgical success rate was expected
to be very high. The findings from this study cannot be
extrapolated to patients with comorbidities such as
chromosomal abnormalities, severe neurologic or devel-
opmental delay, or children greater than 2 years of age.
Only a small number of patients treated surgically
showed inadequate symptom resolution or surgical fail-
ure requiring tracheostomy. Therefore, an adequate
correlation could not be made between failure to improve
symptoms and persistent problems on the growth curve.
These findings suggest that growth curve measure-
ments could be applied in future supraglottoplasty
outcome studies. However, caution must be exercised
when applying the cumulative results of this study to
individual patients. Growth curve measurements are
exactly what they claim. It would be unreasonable to
assume that every child undergoing supraglottoplasty
Fig. 3. Average z-score plotted at T0, T3, T6, and T12. A statisti-
cally significant difference (P <.05) among groups was found only
at T0. The change within the surgical group between 0 and 3
months was also statistically significant (T < 0.05).
Fig. 2. Average z-score at T0, T3, and T>6 for the observation,
medical treatment, and surgical groups. The difference in z-scores
at T0among the three groups was statistically significant (P <.05),
whereas the difference among groups at T3and T>6was >.05.
Laryngoscope 121: July 2011Meier et al.: Growth Curve Changes after Supraglottoplasty
will ultimately achieve the 50th percentile on the growth
curve. Failure for an individual patient’s trajectory on
the growth curve to significantly change after supraglot-
toplasty does not necessarily equate to surgical failure.
Varying indications for surgery must be taken into
account. Individually, not every surgical patient in this
series showed improvement on the growth curve, even
though subjectively most were noted postoperatively to
have excellent outcomes. Part of the limitation in this
series is that patients were not stratified by the indica-
tion for surgery, that is, whether the problem was
Although this study used observed and medically
treated patients as controls, the starting point on the
growth curve was not equal between the three groups.
Those treated surgically were significantly lower on the
curve. Deciding to perform supraglottoplasty on a child
with laryngomalacia and obvious failure to thrive (<5%
on growth curve) is straightforward. More difficult is
making this decision on a child struggling at the 10th,
20th, or even 30th percentile. In this study, many of
these children demonstrated accelerated growth after
surgery. Future prospective studies following growth
percentiles in all patients treated medically or surgically
for laryngomalacia can better identify those intermedi-
or severe breathing
In this series, patients with laryngomalacia severe
enough to warrant surgery presented with significantly
lower percentile weight on a standardized growth curve
than those who required only medical or conservative
treatment. Substantial improvement in growth curve
percentile is seen in the immediate months following
supraglottoplasty. Long-term follow-up after supraglotto-
plasty shows that infants on average return to a mean
weight on the growth curve. These findings suggest that
growth curve measurements can objectively evaluate
supraglottoplasty outcomes, and that infants undergoing
supraglottoplasty have a greater improvement postoper-
than infantstreated medicallyor with
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