Keywords
subglottic stenosis - balloon dilation - endoscopic - laryngotracheal reconstruction
- pediatric
Introduction
Subglottic and tracheal stenoses represent one of the main causes of chronic obstruction
of the airway in children. The important development of neonatology and mechanical
ventilation techniques in the last decades have achieved better survival rates of
preterm infants by variable tracheal intubation periods. Widespread use of these procedures,
converted acquired subglottic and tracheal stenoses in the most common disorder of
the upper airway in children, and in the most frequent indication for tracheostomy
during the first year of life.
Open surgery has been the traditional management of subglottic stenosis (SGS) including
different approaches such as cricoid division, laryngotracheal reconstruction (LTR),
and cricotracheal resection (CTR) with anastomosis, with good results in 80 to 90%.
For this reason, these approaches still remain the first option of treatment.[1] However, they have important disadvantages as the frequent need for several interventions,
with periods of protracted endotracheal intubation in critical care units, and the
risks associated with tracheostomy.[2]
[3]
Significant improvements in airway endoscopy in the last years allowed the development
of new endoscopic techniques for the treatment of subglottic and tracheal stenoses.
Hebra et al[4] published the first experience with tracheal angioplasty balloon dilation in children.
Recently, satisfactory results have been reported in the treatment of acquired SGS
with balloon dilation,[5]
[6] including stenoses appearing after LTR surgery, avoiding reoperations and permanent
tracheostomy.[6]
[7]
[8]
[9]
Nevertheless, management and surgical treatment of subglottic and tracheal stenoses
in children remains unclear because there is still no agreement on the indications.
The aim of this study is to report our experience in the early endoscopic treatment
of acquired subglottic and acquired tracheal stenoses with angioplasty balloon dilation
and topical mitomycin application.
Patients and Methods
Patients with acquired tracheal-subglottic stenoses treated at our center from 2005
to 2012 were retrospectively reviewed. Both postintubation and postlaryngotracheal
surgery stenoses were included. Congenital SGS were excluded. All patients were diagnosed
by bronchoscopy.
We reviewed the etiology, age, clinical presentation, methods of diagnosis, number
of bronchoscopies and angioplasty balloon dilations performed, and long-term results.
Procedure
The patient was placed in the operating room under general anesthesia, maintaining
spontaneous ventilation and nasopharyngeal ventilatory assistance with age-sized nasopharyngeal
tube.
With the patient in cervical hyperextension helped by a roller positioned under the
shoulders, indirect laryngoscopy was performed with instillation of 1% nebulized lidocaine
in vocal cords and supraglottic area (1–2 mL depending on patient's weight). After
that, direct laryngoscopy was done using a 3-mm and 0 degree rigid endoscope (Karl
Storz 10324AA, Tuttlingen, Germany) to establish the level and severity of stenosis
attending to the Myer-Cotton scale[10]:
-
Grade I: obstruction of 0 to 50%.
-
Grade II: obstruction of 51 to 70%.
-
Grade III: obstruction of 71 to 99%.
-
Grade IV: punctiform obstruction without detectable light.
At the time of diagnosis, balloon dilation was performed using angioplasty balloon
catheters 4 to 8 mm in diameter and 20 mm in length (EverCross USA [EV3 Inc., Plymouth,
Minnesota, United States], dilatation catheter), depending on the theoretical diameter
for child's age.
Under direct vision with the rigid scope, the angioplasty balloon was introduced into
the stenotic area and filled with saline by an inflation/deflation hand pump connected
to a pressure gauge that monitored pressure within the balloon. This dilation procedure
was maintained for 1 minute, being interrupted if the patient's oxygen saturation
dropped below 90% or in case of deterioration of vital signs. Two or three dilations
were performed in the same session changing to a larger diameter balloon if necessary.
The dilations were followed by topical application of mitomycin solution (1 mg/mL)
in the dilated area for 1 minute. This local application was performed under direct
endoscopic vision, with a cotton pledget grabbed by a forceps through the rigid bronchoscope
([Figs. 1] and [2]).
Fig. 1 (A) Subglottic stenosis grade III diagnosed with rigid bronchoscopy. (B) Endoscopic
balloon dilation using angioplasty balloon catheter at the time of diagnosis. (C)
Subglottic dilated area. (D) Topical application of pledgets soaked with mitomycin
(1 mg/mL) in the dilated area.
Fig. 2 (A) Subglottic stenosis grade II at diagnosis. (B) Endoscopic balloon dilation. (C)
Dilated area after two episodes of balloon dilation.
Once the procedure was completed, the patient remained during the first 24 hours in
the postanesthetic care unit, and was intubated only if necessary. An intravenous
bolus of methylprednisolone (1 mg/kg) was administrated at the time of the procedure
and repeated 8 hours later, followed by oral tapering doses during the first week,
and aerosol inhaled Budesonide (200 µg, 2 times daily) until the first postoperative
check 2 weeks later.
Revisions were done in the operating room and in the same manner as outlined above.
Except in cases with clinical deterioration, the first one was done routinely 10 to
15 days after the initial dilation. If more dilations were not needed, another endoscopic
check was done 1 month later, and 3 months after the last one. After that, the patient
was followed-up every 6 months in the outpatient clinic ([Fig. 3]).
Fig. 3 (A) Subglottic stenosis (SGS) grade II at diagnosis. (B) Same patient at first revision
2 weeks later showing asymptomatic SGS grade I.
The procedure described above was performed in the operating room whenever the patient's
condition allowed it. If the patient was hemodynamically unstable or had noticeable
respiratory distress, the procedure was performed in the pediatric intensive care
unit using the flexible fiber optic bronchoscope.
Mitomycin was used whenever it was available because the dilution should be previously
prepared by the cytostatic unit; therefore, it could not be applied in all cases,
especially in emergency procedures. In addition, mitomycin was only used in the first
dilation session.
Results
We treated 18 patients (13 male, 5 female) for acquired subglottic or tracheal stenoses
between the years 2005 and 2012. Median age at treatment was 3.5 months (range, 1–96).
A total of 16 children had SGS (all of them after intubation periods), and 2 children
presented tracheal stenosis (1 postintubation, and the other one after reconstructive
tracheal surgery because of a long congenital tracheal stenosis). Median intubation
time before diagnosis was 30 days (range, 3–120 days), and the causes for intubation
were: respiratory distress in 10 cases, cardiac surgery in 5 cases, neonatal abdominal
surgery in 1 cases, and polytrauma after traffic accident in 1 cases ([Table 1]).
Table 1
Clinical data and results
|
Patient n°
|
Age (mo)
|
SGS/TS
|
Etiology
|
Intubation time
|
Grade
|
N° dilations
|
Mitomycin
|
Success
|
Follow-up (mo)
|
|
1
|
1
|
SGS
|
Postintubation. Neonatal abdominal surgery
|
3 d
|
III
|
3
|
Yes
|
Yes
|
32
|
|
2
|
3
|
SGS
|
Postintubation. Respiratory distress
|
2 mo
|
I
|
1
|
Yes
|
Yes
|
50
|
|
3
|
5
|
SGS
|
Postintubation. Cardiac surgery
|
1 mo
|
II
|
3
|
Yes
|
Yes
|
48
|
|
4
|
2
|
SGS
|
Postintubation. Respiratory distress
|
2 mo
|
II
|
2
|
Yes
|
Yes
|
18
|
|
5
|
4
|
SGS
|
Postintubation. Respiratory distress
|
3 mo
|
III
|
4
|
Yes
|
Yes
|
36
|
|
6
|
6
|
SGS
|
Postintubation. Cardiac transplant
|
25 d
|
II
|
2
|
Yes
|
Yes
|
44
|
|
7
|
4
|
SGS
|
Postintubation. Respiratory distress
|
3 mo
|
III
|
4
|
Yes
|
Yes
|
24
|
|
8
|
6
|
SGS
|
Postintubation. Cardiac surgery
|
13 d
|
I
|
1
|
No
|
Yes
|
72
|
|
9
|
4
|
SGS
|
Postintubation. Respiratory distress
|
4 mo
|
II
|
3
|
Yes
|
Yes
|
52
|
|
10
|
3
|
SGS
|
Postintubation. Respiratory distress
|
3 mo
|
II
|
3
|
Yes
|
Yes
|
66
|
|
11
|
2
|
SGS
|
Postintubation. Respiratory distress
|
1 mo
|
III
|
5
|
Yes
|
Yes
|
48
|
|
12
|
9
|
SGS
|
Postintubation. Cardiac surgery
|
20 d
|
I
|
1
|
Yes
|
No
|
44
|
|
13
|
3
|
SGS
|
Postintubation. Respiratory distress
|
3 mo
|
II
|
2
|
Yes
|
Yes
|
32
|
|
14
|
1
|
TS
|
Post laringotracheoplasty in congenital TS
|
1 mo
|
II
|
5
|
Yes
|
Yes
|
30
|
|
15
|
96
|
TS
|
Postintubation and tracheostomy after traffic accident.
|
1 mo
|
III
|
1
|
Yes
|
Yes
|
36
|
|
16
|
1
|
SGS
|
Postintubation. Respiratory distress
|
5 d
|
III
|
4
|
Yes
|
Yes
|
15
|
|
17
|
13
|
SGS
|
Postintubation. Cardiac surgery. CHARGE.
|
11 d
|
II
|
2
|
No
|
Yes
|
7
|
|
18
|
3
|
SGS
|
Postintubation. Respiratory distress
|
13 d
|
II
|
2
|
No
|
Yes
|
5
|
Abbreviations: N° dilations, number of dilations; Patient n°: patient number; SGS,
subglottic stenosis; TS, tracheal stenosis.
The main clinical features were stridor with respiratory distress after a variable
period of intubation, and failure to extubate. Upon bronchoscopy, performed early
as soon as the symptoms appeared, SGS were grade I in three patients, grade II in
nine patients, and grade III in six patients. Bronchoscopy was followed by angioplasty
balloon dilation, with a median of 2.5 sessions (range, 1–5 sessions). The median
of procedures in each group were: 1 in SGS grade I, 2 (range, 2–5) in SGS grade II,
and 4 (range, 1–5) in SGS grade III; with a relation patient/number of dilations of
1 in SGS grade I; 2.6 in SGS grade II and 3.5 in SGS grade III.
Mitomycin was applied during the first dilation session in 15 of 18 patients. All
patients were treated successfully with this procedure and no one presented intraoperative
complications or required open surgery. The patient with the posttracheal surgery
stenosis did not need reoperation. Median follow-up time was 36 months (range, 5–72
months) and no recurrences or side effects have been noticed.
Discussion
Congenital and acquired subglottic and tracheal stenoses remain a challenge for pediatric
surgeons because there is no consensus on their management and surgical treatment.
In our hands, early and vigorous dilation of acquired SGS was effective and safe,
and the number of sessions was proportional to the grade of stenosis. The success
of this procedure was less dramatic in patients with long-standing SGS or tracheostomy
because of intense fibrosis. Before the angioplasty balloon dilation was introduced
or in a few occasions when they were not available, dilation was performed with rigid
bronchoscopes or with the endotracheal tube itself, but the results were definitely
worse with poor control over the dilated area. In congenital stenosis, we avoid dilatation
because of the risk of tracheal wall rupture and we prefer open surgery procedures,
such as LTR with costal cartilage grafting, CTR, or slide tracheoplasty in longer
stenoses.
Several surgical procedures have been used for the treatment of subglottic and tracheal
stenosis. In the late 1980s, the gold standard was the reconstructive surgery (LTR),
including cricoid division with subsequent reconstruction using autograft cartilage
and endotracheal stents.[11] The laryngotracheoplasty in a single surgical procedure was introduced in the late
1990s, replacing postoperative tracheostomy for endotracheal intubation, with a success
rate approaching 80%.[1] At the same time, Monnier et al introduced the partial CTR for severe SGS and anastomosis
with successful results.[12]
In the past years, important advances of minimally invasive airway endoscopic surgery
have been developed, particularly, laser resection and laryngotracheal dilation. These
less risky procedures achieved shorter periods of intubation and reduced postoperative
stay.[13]
[14] Endoscopic laryngotracheal dilation could be done both with rigid dilators and with
inflatable balloons. A descriptive study of 64 patients with acquired SGS grade I–III
dilated early and repeatedly with Chevalier–Jackson rigid dilators, had a 100% success.
Patients with more severe grades of stenosis required more sessions.[15]
Despite the demonstrated efficacy of balloon dilation in angioplasty and in esophageal
stenosis, there is reluctance for using it in the infant airway being the main argument
the absence of clinical trials or prospective studies comparing open surgery with
endoscopic dilations.[7] The pneumatic balloon dilations hypothetically offer several advantages over rigid
ones, such as exerting radial force instead of longitudinal shearing wall forces,
and the ability to control the diameter and the pressure of the balloon, that is able
to limit the trauma on the tracheal wall.[4]
[16]
Recent studies reported satisfactory outcomes in the endoscopic balloon laryngotracheoplasty
of acquired and congenital SGS.[5]
[6]
[7]
[8] Hautefort et al[6] published good results using balloon dilation in the treatment of 44 patients with
acquired SGS, congenital SGS and posttracheal surgery stenoses, showing a successful
treatment in 70% of acquired SGS, 50% in congenital SGS, and 81% in stenosis after
open laryngotracheal surgery. Authors concluded that tracheal balloon dilation has
become for them the first therapeutic option in the acquired SGS of all grades, stenosis
secondary to prior reconstructive surgery and in selected cases of congenital SGS,
reducing the need for open approach in 70 to 80% of the cases. Whigham et al[8] established that balloon dilation plays an important role in the management of pediatric
SGS, being concomitant airway lesions associated with treatment failure. Mirabile
et al[16] recently communicated their favorable experience with 83% of success in both acquired
and congenital SGS with endoscopic anterior cricoid split and balloon dilation, suggesting
a better outcome in congenital SGS with the anterior cricoid division.
Other groups have also reported satisfactory results in the endoscopic management
of the SGS using various techniques (balloon dilation, rigid dilation, and laser resection),
as well as different adjuvant topical treatments with mitomycin, steroids, and/or
antibiotics; therefore, results cannot be attributed to any particular technique.[9]
[14]
On contrary, open techniques (LTR and CTR) continue to be widely used in both acquired
and congenital subglottic-tracheal stenosis with good results, but with a significant
percentage of reoperations and decannulation failures. White et al[2] presented 94% successful decannulation rate in 93 patients who undergone CTR, but
an operation-specific success rate of 71% (27 patients required additional open airway
procedures for decannulation after CTR). The group of Great Ormond Street Hospital
in London, United Kingdom, recently published their experience with LTR and CTR in
199 patients from 2000 to 2010, showing 88% improvement in patient's symptoms, but
16.5% children who underwent single-stage procedures had a tracheostomy reinserted.
Furthermore, two-stage LTR/CTR procedures were performed in 57.7% of the patients
with prolonged stenting periods.[17] Therefore, even if they are effective techniques, the risk of reintervention or
decannulate failure make endoscopic procedures more attractive and increasingly used.
Mitomycin-C is an antibiotic produced by Strepnomyces caespitosus that has antiproliferative and antineoplasic properties.[18]
[19] Its antineoplasic activity is similar to that of the alkylating agents, causing
single-band breakage and cross-linking of DNA at the adenosine and guanine molecules,
inhibiting DNA synthesis by blocking DNA-dependent RNA synthesis and therefore inhibiting
RNA and protein formation.[19]
[20] Recent experiments have shown that the mechanism of action is probably more profound.
It has been suggested that mitomycin-C would bind at the promoter sites of the inducible
genes involved in wound healing, therefore inhibiting expression of those genes.[21] So as an antiproliferative agent, mitomycin can inhibit fibroblast proliferation
and decrease scar formation, having gained wide relevance as a preventive scar formation
treatment in different fields such as ophthalmology and in the respiratory and digestive
tracts. It has shown encouraging results in the treatment of pediatric refractory
esophageal strictures[18]
[19] and in the prevention and treatment of laryngeal and tracheal stenosis.[9]
[20]
[22]
[23]
We employed a mitomycin solution at a concentration of 1 mg/mL, which is the dosage
used for other authors,[9]
[18] and no side effects appeared during follow-up. However, lower dosage of mitomycin
(concentration between 0.1 and 1 mg/mL) has also been shown to be effective.[18]
Nevertheless, it is difficult to know what is the real effect of mitomycin application
is in these patients. There are no prospective studies comparing both procedures (endoscopic
dilation with mitomycin vs. without mitomycin).
Patients with acquired or congenital SGS present different clinical features (age,
location, severity and length of the stenosis, and associated comorbidities) that
are closely related to the prognosis and final outcome. These conditions are variable
in each patient, so comparative studies between traditional open surgery and endoscopic
techniques are difficult to perform. Therefore, descriptive case series are important
to know the management and surgical indications in this pathology.
Conclusion
Early endoscopic balloon dilation after the appearance of symptoms was an effective
and safe treatment in acquired tracheal and subglottic stenoses.
In our experience, all patients were treated successfully with this procedure, avoiding
open laryngotracheal interventions and reoperation in case of previous surgery. For
this reason, we elected endoscopic balloon dilation as the first treatment option
in all grades of acquired tracheal and SGS, reserving open laryngotracheal surgery
for congenital SGS and for those high-grade, acquired stenoses unsuccessfully treated
after several endoscopic procedures.
We are aware that we cannot exactly size the contribution of mitomycin application
in our patients. Comparative prospective studies are needed to know the real benefit
of its use, its optimal dosage, time, and type of application before setting recommendations
about its use.
