Orphanet J Rare Dis. 2011; 6: 81.
Published online 2011 Dec 7. doi: 10.1186/1750-1172-6-8
Laryngo-tracheo-oesophageal clefts
A
laryngo-tracheo-esophageal cleft (LC) is a congenital malformation
characterized by an abnormal, posterior, sagittal communication between
the larynx and the pharynx, possibly extending downward between the
trachea and the esophagus. The estimated annual incidence of LC is
1/10,000 to 1/20,000 live births, accounting for 0.2% to 1.5% of
congenital malformations of the larynx. These incidence rates may
however be underestimated due to difficulty in diagnosing minor forms
and a high mortality rate in severe forms. A slightly higher incidence
has been reported in boys than in girls. No specific geographic
distribution has been found. Depending on the severity of the
malformation, patients may present with stridor, hoarse cry, swallowing
difficulties, aspirations, cough, dyspnea and cyanosis through to early
respiratory distress. Five types of laryngo-tracheo-esophageal cleft
have been described based on the downward extension of the cleft, which
typically correlates with the severity of symptoms: Type 0
laryngo-tracheo-esophageal cleft to Type 4 laryngo-tracheo-esophageal
cleft. LC is often associated with other congenital
abnormalities/anomalies (16% to 68%), mainly involving the
gastro-intestinal tract, which include laryngomalacia, tracheo-bronchial
dyskinesia, tracheo-bronchomalacia (mostly in types 3 and 4), and
gastro-esophageal reflux disease (GERD). The syndromes most frequently
associated with an LC are Opitz/BBB syndrome, Pallister Hall syndrome,
VACTERL/VATER association, and CHARGE syndrome. Laryngeal clefts result
from failure of fusion of the posterior cricoid lamina and abnormal
development of the tracheo-esophageal septum. The causes of the
embryological developmental anomalies leading to LC are not known but
are thought to be multifactorial. LC appears to be mostly sporadic
although some familial cases with suspected autosomal dominant
transmission have been reported. The age of diagnosis depends mainly on
the severity of the clinical symptoms and therefore on the extent of the
LC. Diagnosis is made either based on clinical manifestations or on
investigations, such as endoscopy, X-ray, CT scan, performed for other
conditions. Differential diagnoses include tracheo-bronchial fistula,
gastro-esophageal reflux disease and neurological swallowing disorders,
as well as laryngomalacia and laryngeal palsy. Prenatal diagnosis of LC
has never been reported, although associated anomalies may be detected
on fetal ultrasonography. Once the cleft is diagnosed, it is essential
to determine its length to orient the management and treatment approach.
Management involves maintenance of satisfactory ventilation, prevention
of secondary pulmonary complications as a result of repeated
aspirations, and adequate feeding. Endotracheal intubation may be
required for respiratory distress in severe cases. Treatment requires
endoscopic or external surgery to close the cleft. Surgery should be
performed as early as possible to avoid complications related to
aspiration and gastric reflux, except in type 0 and type 1 cases in
which conservative measures must first be attempted. The prognosis is
variable depending on the severity of the LC and associated
malformations. Early diagnosis and appropriate treatment and management
help to reduce mortality and morbidity.
Review
Historical delineation and disease definition
The
first reported clinical case of laryngo-tracheo-oesophageal cleft was
made by Richter in 1792 in a newborn presenting with recurrent
aspiration [1]. The first successful surgical reconstruction was performed in 1955 [2], and the first reliable classification system was proposed in 1965 after a review of all available literature [3].
The first large and well documented series, illustrating the guidelines
of diagnostic and therapeutic strategies, was proposed in 1983 [4]. Since then, numerous manuscripts have been published regarding laryngo-tracheo-oesophageal clefts and their management.
.
A laryngeal-tracheo-oesophageal cleft (commonly termed laryngeal cleft,
LC) is a congenital malformation of the posterior part of the larynx,
possibly extended to the trachea, creating an abnormal communication
between the laryngo-tracheal axis and the pharyngo-oesophageal axis
(Figure (Figure1).1).
Thus, the physiological separation between the airway and the digestive
tract is lost, leading to chronic cough, aspiration, respiratory
distress, pneumonia.... The severity of a LC is directly correlated to
the downward extension of the cleft. This disease is registered in both
Orphanet (ORPHA2004) and OMIM (#215800) databases [5].
Recent
advances in knowledge, diagnosis and, above all, the treatment of LC,
have led to significant improvements in survival and quality of life of
these patients.
Classifications
Over
the past 50 years, many classifications of LC have been proposed, all
based on the downward extension of the cleft: Petterson (1955), Armitage
(1984), Evans (1985), Benjamin (1989), Meyer (1990), DuBois (1990), and
Sandu (2006) [6]. All have a threefold interest:
- Descriptive; allowing the comparison of a series of patients in the literature;
- Therapeutic; influencing the choice of a reconstructive technique and surgical approach
- Prognostic; as success and survival rates are highly correlated to the extension of the LC.
To date, the Benjamin and Inglis classification [7], modified by Sandu in 2006 [8], are the most frequently used (Figure (Figure2).2).
Indeed, they differentiate partial and total cleft of the cricoid
cartilage, as well as cervical and tracheo-thoracic cleft. Those
elements are essential in the choice of a therapeutic strategy.
Type 0: submucosal cleft
Type I: supraglottic, interarytenoid cleft, above the vocal fold level
Type II: cleft extending below the vocal folds into the cricoid cartilage
Type III a: cleft extending through the cricoid cartilage but not into the trachea
Type III b: cleft extending through the cricoid cartilage and into the cervical trachea
Type IV: cleft extending into the thoracic trachea, potentially down to the carina
Submucosal LC was initially described by Tucker in 1987 [9]
as a posterior, sagital, submucosal, cartilage defect with intact soft
tissues (mucosa and interarytenoid muscle). It is clinically relevant,
since it has been described with other anomalies of the cricoid
cartilage, including congenital subglottic stenosis [10].
Epidemiology
LC
is a rare, congenital, anomaly. It is widely accepted that its
incidence is probably underestimated. Indeed, 1) minor LC (type 0 or
type 1) may either be asymptomatic or show only mild symptoms; 2) the
endoscopic diagnosis is difficult and several reports exist a missed
malformation despite a well-conducted endoscopic assessment; 3)
high-grade LC (type 4) have a high mortality rate, often leading to the
patient's death before diagnosis can be made; 4) the endoscopic
assessment may not be a priority in cases with numerous associated
malformations.
As such, the estimated incidence of LC is 1 in 10,000 to 20,000 living births [6,11,12], representing about 0.2% to 1.5% of the congenital malformations of the larynx [10,13-17].
From
1990 to 1995, of the 2,338 endoscopies carried out in a specialized
paediatric department, only 7 cases of laryngeal cleft were identified
(0.3%) [10]. In 1971, a review of 433 cases of laryngeal malformations identified 2 cases of LC (0.5%) [17].
An initial study conducted between 2002 and 2005, found among 264
patients evaluated for chronic cough or aspiration, 20 cases of type I
LC (7.6%) [18].
This incidence, higher than that previously mentioned, appears to be
more in line with reality due to: 1) a better understanding of the
disease and its diagnosis and 2) a pre-selection of patients.
LC has a slightly higher incidence in boys than in girls, with a ratio of 1.2 [19] to 1.8 [20].
Even if data on this subject is scarce, no evidence appears to exist
relating to an occurrence of a specific racial predominance [20].
Cases of LC appear to be mostly sporadic. However, reports exist of
families with multiple children having a cleft. In these patients, the
possibility of an autosomal dominant transmission has been suggested [21].
Alcohol and/or drug abuse during pregnancy, multiple miscarriages,
hydramnios and prematurity are frequently reported, but none have been
proven to be a specific risk factor [1,10].
Etiopathology: embryology and animal model
In
the classic embryological description of the respiratory system, the
larynx develops from two tissues evolving in parallel: the endoderm
coming from the foregut and the mesenchymal elements from the 4th and 6th branchial arches [22].
The division of the foregut is the result of the fusion of lateral
ridges appearing in the lateral walls of the foregut. This process
starts caudally and ends cranially to the region of the larynx, thus
forming a septum that divides the foregut into a ventral portion - the
laryngo-tracheal tube - and a dorsal portion - the oesophagus.
Recently,
researchers studying the embryology of the foregut of chick embryos,
failed to identify subtle lateral ridges and suggested that the
development of both the trachea and the oesophagus could result from a
size reduction of the foregut, caused by a system of folds that get
close but do not merge [22].
This system of folds could appear in the foregut and involve the
tracheo oesophageal space in both the cranial and caudal areas: the
caudal with a cranial development and the two cranial folds with a
caudal evolution. Moreover, the respiratory diverticulum has also been
described; the latter developing from the ventral area of the foregut
and continuing to elongate downward to form the trachea [23].
The portion of the mesenchyme, known as the tracheo-oesophageal septum,
located between the digestive and respiratory tracts, is the result of
the separation of the two tracts. Apoptotic mechanisms are also involved
in the growth and evolution of tissues: apoptotic epithelial cells can
be found at the tracheo-oesophageal separation site in the ventral part
of the foregut, where cellular activity is intense, whereas the dorsal
part remains inactive [24].
Several models have been proposed to explain tracheo-oesophageal anomalies, including LC [25]:
- Intra-embryonic pressure:
an intense curvature of the cervical region, during the heart's
development, could cause a strain and a displacement of the oesophagus,
resulting in growth anomalies.
- Epithelial occlusion:
the oesophagus has a solid stage of development, and eventually
re-canalizes. A failure of this latter process could result in
malformations.
- Vascular occlusion: the persistence of an abnormal vessel could lead to vascular insufficiency in the foregut, resulting in growth anomalies.
- Differential cell growth:
abnormal cell development in either the ventral or dorsal part of the
developing tracheo-oesophagus could result in oesophageal or tracheal
defects.
It has been suggested that a premature arrest
in development of the tracheo-oesophageal septum, and the lack of fusion
of the two lateral parts of the developing cricoid cartilage, could be
responsible for LC [3].
This model, however, does not explain the mechanism of associated
malformation, such as laryngeal atresia and tracheo-oesophageal fistula.
An animal model of laryngo-tracheal malformations has been described in rat embryos exposed to doxorubicin (Adriamycin®) [25-28].
After exposure, these embryos display major tracheo-oesophageal
anomalies, similar to those described in the VACTERL association
(oesophageal atresia and tracheo-oesophageal fistula). However, LC has
not yet been observed in this model under experimental conditions.
Clinical description
Clinical symptoms
The intensity of clinical symptoms of laryngeal clefts typically correlates with the type of cleft itself [10,19]. Most frequent symptoms are summarized in Table Table11.
Type 0 clefts
may display mild to no obvious symptoms (occasional aspiration) when
clinically isolated, but association with other airway malformations or
syndromes is possible. They are often discovered during an endoscopy or
an external procedure initiated for other reasons, and their diagnosis
is especially difficult if the surgeon is not aware of their clinical
appearance [9,29,30].
Type I clefts
usually present with mild to moderate symptoms, including stridor, a
toneless or hoarse cry, and swallowing disorders. Aspiration, cough,
dyspnoea and cyanosis during feeding are possible but not routine. The
impact on the pulmonary tract is usually none to mild.
Type II and III clefts usually display more swallowing disorders (aspiration mostly) and pulmonary tract infections.
Type IV has
a poor prognosis, due to the early respiratory distress they cause, and
to the difficulty of maintaining correct mechanical ventilation [20,31-33].
However,
some cases of large LCs with a surprisingly little symptomatology have
been documented. It is supposed that the excess of oesophageal mucosa
herniating into the cleft in the LC provides, in these cases, some
degree of protection against aspiration. However, this mucosal hernia
has also been proposed as the cause of stridor and airway obstruction.
The
age at which a diagnosis is made depends mostly on the severity of the
clinical symptoms, and therefore on the extent of the LC itself.
Moreover, the experience of the medical team managing the LC may also
influence the age at which a diagnosis is made, especially when the
associated malformations are mild or none [14,16,34].
In the literature, the age at diagnosis is very variable. Thus, in one
series, type 0 LC were diagnosed at an average age of 6 months, type I
before the age of 6 months and type II before the age of 2 months [19]. In another series, [29], the average age at diagnosis, regardless of the type of cleft, was 15 days to 12 years of age.
Thus,
every swallowing disorder (cough during feeding, aspiration and/or
cyanosis) should lead to an endoscopic examination of the child's
airways to assess for a LC.
Associated syndromes
LC is often associated with other congenital abnormalities (16% to 68%), mostly malformations of the digestive tract [4,29]. A full examination of both digestive and respiratory tracts is therefore mandatory during the assessment of a LC.
These
associated malformations may be syndromic or appear isolated. Four
syndromes are among the most frequently associated with a LC:
-
The Opitz G/BBB syndrome (Orpha2745/OMIM #145410), characterized by
laryngeal malformations (including LCs) which are associated with
craniofacial anomalies (pinna malformations, cleft lip and palate,
hypertelorism), genitourinary anomalies (hypospadias), and other
malformations of the ventral midline. Two forms exist: one with an
autosomal dominant inheritance and the other with an X-linked
inheritance.
- The 22q11 monosomy (CATCH 22, 22q11
microdeletion, DiGeorge syndrome...) (Orpha567/OMIM #192430 and
#188400). This syndrome may include numerous malformations especially
hypoplasic thymus and parathyroid glands, cardiopathy, velopharyngeal
insufficiency with or without cleft palate, and sometimes LC. The
clinical course mainly depends on the malformations involved. Its
overall incidence is estimated at 1/5000 births, but is much lower when
associated with LC.
- The Pallister Hall syndrome
(Orpha672/OMIM #146510) is characterized by the association of laryngeal
(LC), gastrointestinal, cardiopulmonary, limb (polydactyl and
syndactyl) and neurological malformations (congenital hypothalamic
hamartoblastoma with hypopituitarism). Its inheritance is autosomal
dominant.
- The VACTERL association (Orpha887/OMIM
#192350). Its aetiology is still unknown in man. The acronym stands for
Vertebral, Anal, Cardiac, Tracheo-oesophageal (including LC), Ear
(middle and inner), Renal, and Limb malformations.
-
The CHARGE syndrome (Orpha138/OMIM #214800) results in the main, from a
CHD7 gene mutation. The acronym stands for Coloboma, Heart
malformations, choanal Atresia (uni- or bilateral), growth and mental
Retardation, Genitourinary malformations, and Ear malformations
(external, middle, and inner ear). Several other malformations may also
be associated, some of them constant (e.g. olfactory bulb hypoplasia and
semi-circular canal anomalies). An LC may also be associated with many
other cranial malformations (cleft lip and palate, laryngomalacia,
laryngeal webs...).
Furthermore, several other associated malformations are possible as shown in Table Table2.2.
It is likely that most of these malformations are in fact linked to
not-yet identified syndromes. However, a purely isolated LC is also
possible.
Diagnostic methodology
Endoscopic examination
Several
different diagnoses are possible, and among them tracheobronchial
fistulas, laryngomalacia, laryngeal palsy, gastro-oesophageal reflux
(GERD), neurological swallowing disorders... Most of these diagnoses can
be ruled out during the endoscopic examination.
The
endoscopic assessment is essential to LC diagnosis. It must be conducted
with special care and attention, because it is possible to miss a
low-grade malformation if the examiner is not especially aware of it [15].
Such endoscopic examination must be conducted in the operating room and includes:
-
A fiberoptic examination of the larynx under local anaesthesia, looking
for laryngomalacia, direct aspiration, and assessing laryngeal mobility
and sensitivity. A LC may be suspected at this time, but usually cannot
be diagnosed with certainty [29].
-
A full examination of the airways and the oesophagus with rigid
telescopes, under general anaesthesia with spontaneous breathing, in
order not to miss a tracheo-bronchial dyskinesia, or a tracheo-bronchial
laryngomalacia (50 to 66%). The entire respiratory tract must be
assessed because tracheo-bronchial fistulas are associated in 10 to 60%
of the cases [34,35].
The
larynx must then be examined with microlaryngoscopy during a laryngeal
suspension, using high magnification either with a microscope or video
monitored telescope [36]. A preliminary topical application of 1% lidocaine may
help before cleft palpation. The posterior glottis must be carefully
inspected and palpated, looking for a sagittal cleft between the
digestive and the respiratory tracts (Figure (Figure3).3).
A LC may be inadvertently overlooked because of the redundant mucosa
between the oesophagus and trachea, prolapsing into the cleft. Several
probes have been designed and proposed for cleft palpation [16]. Once the diagnosis is made, it is fundamental to assess the length of the cleft [11].
The endoscopic examination may also show associated anomalies such as:
- tracheo-bronchial dyskinesia [11]
- tracheo-oesophageal fistula [20]
Radiological assessment
Routine
chest X-rays are usually not conclusive and may only provide signs of
parenchyma anomalies secondary to aspiration. It has been reported on
CT-scans, in some patients, that an abnormal communication and a lack of
soft tissue exists between the trachea and the oesophagus can
occasionally be found [39], as well as an abnormal anterior or intra-tracheal position of a nasogastric tube [6,10].
However, neither standard X-ray examinations nor CT-scans are commonly
used to diagnose an LC. Similarly, MRI scans are also not commonly used
in the diagnosis of LCs, but they are usually needed to assess the
associated malformations.
A barium
swallow study, most often used to locate a tracheo-oesophageal fistula,
will immediately show the flow of the barium into the trachea thereby
possibly leading to a false diagnosis of a tracheo oesophageal fistula
due to a lack of knowledge of laryngeal clefts by radiologists [15].
Diagnostic methods and complemenraty investigations
Once
a LC has been diagnosed, a systematic course of action is critical.
This includes, in addition to the endoscopic assessment, at least [1]:
-
A genetic counselling with family history, full clinical examination
and systematic karyotype. According to the clinical findings, specific
genetic gene anomalies will be looked for by cytogenetic techniques
(e.g. MID-1 for Opitz G, TBX1 for 22q11 microdeletion, GLI3 for
Pallister Hall, CHD7 and SEMA3E for CHARGE...). However, in some cases,
even presenting with typical clinical features, no specific genetic
anomalies can be found.
- Cardiac and renal ultrasonographies
- Spinal (cervical) x-rays
- Hearing screening
In
the frequent case of associated malformations requiring surgery, the
choice of the surgical sequence will be made according to the child's
condition and respiratory status.
Treatment
Medical management
Medical
management aims to: 1- maintain satisfactory ventilation in children
presenting an obstructive form of LC (mostly by prolapsing mucosa), 2-
prevent secondary pulmonary complications as a result of repeated
aspiration and 3- ensure adequate feeding of the child.
In
cases of respiratory distress (possibly neonatal), an endotracheal
intubation may be required. This procedure carries for LCs (except for
grades 0 and I), a high risk of tube misplacement and should be
undertaken under endoscopic control. For grade 4 LCs, the stability of
the tube in the airway and the quality of mechanical ventilation may be
difficult to maintain. Placing the tip of the tube very close to the
carina is helpful. If a tracheotomy is decided upon, the placement of
the cannula also requires an endoscopic control. In extreme type IV LCs,
trachea and oesophagus are merged in one single tract and ventilation
is extremely hard to maintain; the prognosis is therefore very guarded [6,15,19,39,40].
Noninvasive
positive pressure ventilation (continuous or bi-level positive air
pressure) is not recommended in children with a non-operated LC, because
of: 1- the mobile, mucosal, obstructive component of the airway which
can be displaced by the positive pressure, thus worsening the
obstruction and 2- the increased risk of secondary pulmonary infection
resulting from the aspiration, increased by the air flow. However, in a
case of relapse of obstructive symptoms after surgery, this non-invasive
ventilation technique may be helpful.
In a recently
operated upon child, an endotracheal intubation (e.g. for a secondary
respiratory distress) should be approached with extra care, for it can
compromise the surgical reconstruction before healing is complete.
Children
with a mildly symptomatic type I LC may be fed with thickened food,
generally with good success. GERD treatment and postprandial upright
position are also helpful [34,41,42]. Patients with a symptomatic type I or II LC will benefit from an anti-reflux treatment and nasogastric tube feeding [29].
In some cases of significant type III or type IV clefts, the risk of
aspiration is so high that parenteral nutrition may temporarily be
necessary [39,43]. High grade LCs often require a mid- to long- term gastrostomy (often with fundoplication) [11,35,37]. Gastric division with a proximal drainage tube and distal gastrostomy have also been proposed for type IV LCs [36,44-46].
Surgical management
Two
surgical standards exist for LCs: the external and endoscopic
approaches. The classical, systematic, external approach has been
partially replaced by endoscopic procedures during the last decade.
However, high grade LC or cases of endoscopic failures still require a
classical approach.
• External approach
Approaching the cleft
Depending
on the type of LC and the experience of the surgical team, different
cervical approaches are possible: lateral with lateral or posterior
pharyngotomy, and anterior laryngotracheal.
The lateral
approach with lateral pharyngotomy has been recommended for low grade
LCs with less than 2 cm of cervical trachea involved [6].
Its drawback is the risk of recurrent and pharyngeal injuries to the
nerves The lateral approach with posterior pharyngotomy is seldom used [15].
The risk of nerve injury is lower, but the control of the upper part of
the cleft in the interarytenoid region can be difficult [19].
The
anterior laryngotracheal approach is the most widely used open
technique. It provides an excellent exposure of the cleft with minimal
neck dissection, and presents no risk of nerve damage (Figure (Figure4).4).
Once the cleft is closed, it is fundamental to ensure the postoperative
stability of the larynx. Despite early concerns, it has been shown that
the larynx has a normal growth pattern after such a procedure [47].
In brief, the skin incision is horizontal at the level of the
cricothyroid membrane. After sectioning off the thyroid isthmus, the
larynx is opened vertically, in accordance with the width of the cleft.
The airway can be maintained per-operatively by either a tracheotomy [19,48,49] or an endotracheal tube placed in the tracheal incision and replaced by a standard intubation at the end of the procedure [1,34,47].
Our preference is for the latter technique, which avoids: 1- an
additional tracheal trauma, 2- a potential tracheal ischemia by
compression, and 3- the morbidity of a paediatric tracheotomy.
Type III LC, per-operative anterior view (external approach); *: arytenoids; o: esophagus. The posterior wall of the pharynx is visible thru the cleft.
Two
types of thoracic approaches have been described: anterior (with a
sternotomy) and lateral; both combined with a cervical incision [20,44,46,50-53].
Combined cervical and thoracic approaches are only indicated in type IV
clefts, and may also require cardiopulmonary bypass or extracorporeal
membrane oxygenation [51-53].
Closing the cleft
Several closure techniques have been described: 1- a multi-layer closure after excision of excess mucosa [34,54] and 2- the use of asymmetric flaps with non-overlapping suture lines [39,48].
The first concern with both those reconstructive techniques is the risk
of ischemic damage on the recently created suture line by the
endotracheal tube, a tracheotomy or the nasogastric tube. Because of
this risk, the authors believe that the use of a temporary endotracheal
tube is preferable to a tracheotomy [34,51]; similarly, a gastrostomy is preferable to a long-term nasogastric feeding tube.
In order to lower the risk of secondary opening, interposition grafts can be used: tibial periosteum or auricular cartilage [34], sternocleidomastoid muscle flap [20], fascia temporalis [55], costal cartilage [56], pleural flap [43,50,57], or even pericardium [51].
The authors prefer tibial periosteum as primary grafting material
because it is easy to harvest and manipulate, and due to the satisfying
results experienced by the authors in this indication [29,58].
Even
after an uneventful procedure, and irrespective of the technique used,
the risk of relapse of the LC (secondary re-opening of the cleft)
requiring a revision is high: currently documented at 11% to 50% [29,43,46,58-61]. Thus, multiple procedures are common in LC management.
Tracheomalacia
is a frequent issue in the post-operative management of type III and
type IV clefts, and may require the use of a stent by tracheotomy [45,46,51], excision of the malacic segment [12], aortopexy [12,46], or positive pressure ventilation [34,37,38,45,62].
The
latter is a non-invasive technique, which generally allows a
satisfactory control of the obstructive symptoms without additional
surgical procedures, and, in the authors opinion, should be the intended
first.
• Endoscopic approach
Since
its early beginning in the 1980's, numerous publications have described
the endoscopic technique for the closure of type I and type II LC [8,29,41,55,58,60,63,64]. Recently, successful cases of endoscopic closure of type III clefts have also been reported [58,60].
Endoscopic
surgery has many advantages: no skin incision, no laryngeal opening,
and the possibility of repeating the surgery easily without great
additional morbidity. It is performed under general anaesthesia with
spontaneous breathing and thus requires an experienced team of
paediatric otolaryngologist surgeons and anaesthesiologists. Type I
clefts have been closed endoscopically with an endotracheal tube in the
airway [6], but spontaneous breathing allows an optimum exposure of the operating field itself.
The
cleft closure is performed under suspension laryngoscopy, using a
microscope and specific cold instruments: an endoscopic needle driver
and a knot pusher [29,58,60]. Most authors also prepare the cleft before closure by denuding the mucosal margins using a CO2 or Thulium (Revolix©,
LISA Laser, Katlenburg-Lindau, Germany) LASER. The dissection of the
cleft, necessary prior to the two-layer non-absorbable suture (e.g.
Prolene© 6/0 dual 9.3 mm needle) requires regular
microlaryngoscopy instruments (Collin ORL, Bagneux, France) and mostly
experience and patience from the surgeon and his assistant. The sutures
are ideally placed on the pharyngeal side of the posterior wall of the
larynx, in order to avoid irritation of the larynx and fall into the
airway. In neonates or small infants, especially with a respiratory
condition, the realization of a 2 layer suture may be difficult to
achieve. In these cases, one must be careful to perform at least a
1-layer suture closure with 3 or more sutures. The sutures have to be
tight enough to limit secondary opening of the cleft, but must not
narrow the laryngeal lumen or be an obstacle to arytenoid movement.
The
patients usually spend the first night in intensive care because of the
risk of secondary oedema leading to respiratory distress, and can be
fed after 7 to 14 days. Some authors prefer a re-intubation for a few
days [18], and others non-invasive ventilation [8].
Endoscopic
positioning of an interposition graft is technically very difficult,
not to say impossible. However, authors have experienced the use of
complementary materials, with varying success rates: collagen [65], Gelfoam® [66], and more recently bioplastic [64],
in order to improve long-term results, Bioplastic beingless absorbable
than the previous materials. These procedures with injectable materials
have been mostly proposed in type I clefts and remain used by few teams.
Moreover, in light of the good results of endoscopic procedures without
injectable materials, long-term results involving more patients are
required before these techniques can be recommended.
The
low morbidity and the favourable results of the endoscopic approach
have made it the technique of choice for type I and II LCs. Moreover,
several cases of type III LC successfully treated by endoscopic means
have recently been reported [1,29,58,60].
However, it is likely that despite the advances in surgery and
anaesthesiology, some type III and all the type IV will never benefit
from the endoscopic approach.
• Therapeutic timing and strategy
The
prognosis of LC is closely linked to the grade of the cleft, the
associated conditions, and the pulmonary status of the patient. In all
cases, surgery should be performed as soon as possible to avoid
complications related to the aspiration and gastric reflux [11,29,41,51].
However, the degree of severity and thus the need for rapid management
is very different between the different forms of the disease.
Submucosal
clefts can be especially problematic. In the rare cases where they are
the only malformation and have no clinical impact, a watchful
surveillance can be proposed. However, the presence of a submucosal
cleft has been described as a contributing factor to the failure of an
airway reconstruction procedure. Thus, this type of cleft should be
taken care of concomitantly with to the other malformation, usually with
a posterior graft via an external approach [30].
A
toddler with a grade 1 LC presenting with mild symptoms and occasional
aspiration - without associated conditions - will be managed very
differently to a newborn with a grade 4 LC, (massive saliva aspiration,
unstable endotracheal intubation, associated great vessel malformations)
and whose survival will be compromised during the first hours of life.
Prognosis
During
the recent decades, advances in both medical care and surgical
techniques have notably improved the prognosis of LCs. The overall
mortality rate in a series of patients in 1983 was 46% [4] and has dropped to 6% - 25% in most recent reports [54,55,58,60].
This improvement in survival can be explained not only by the advances
in treatment and management, but also by an earlier diagnosis. Indeed,
the sooner a diagnosis is made, the greater the reduction in morbidity
and mortality.
However, comparing
different series is difficult because of: 1- the low incidence of
pathology, 2- the inhomogeneity of the groups of patients in these
series, 3- the important differences in clinical presentation and
prognosis of the different grades of LC, and 4- the impact of associated
malformations. The mortality rate for type IV LC only, for example, was
estimated at 93% in 1985 [4] and is now below 50% [32,37,54].
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