Benjamin and Inglis (1989)
Sandu and Monnier (2006)
Interarytenoid cleft with the absence of the interarytenoid muscle
Cleft with partial cricoid involvement
Posterior cleft extending partially through the cricoid plate
Cleft beyond the cricoid cartilage with involvement of the cervical trachea
Posterior cleft extending down to the inferior border of the cricoid plate
Posterior cleft extending into the cervical trachea, but not beyond the sternal notch
Involvement of thoracic trachea
Laryngotracheal cleft extending into the intrathoracic trachea to the carina
Intrathoracic extension of the cleft involving one main bronchus
From an embryologic perspective, the larynx develops from endodermic tissues (which in turn derive from the primitive gut) as well as mesenchymal tissues derived from the IV–VI branchial arches. Toward the fourth week of development begins the midline fusion which is meant to lead to the separation of the digestive (esophageal) and respiratory (tracheal) axes. This fusion process takes place in the caudal to cranial direction . The esophagus elongates and reaches its final relative length toward the seventh week. LTCs are pathological clefts thought to be the result of a closure failure between the tracheal and esophageal axes during embryogenesis, but despite the explanatory power of this theory, it is important to point out that it has been challenged as it does not allow explaining the origin of other pathological entities such as isolated tracheoesophageal fistulae.
10.2 Diagnostic Aspects
Several grading classifications for LTCs have been proposed, primarily based on the craniocaudal extent of the cleft. Such classifications are mainly descriptive, help in therapeutic choices, and have to some degree prognostic value. The most widely used classification is the one proposed by Benjamin and Inglis in 1989 . Benjamin’s classification was modified and updated by Sandu and Monnier  in 2006, in order to introduce parameters with therapeutic and prognostic implications previously overlooked (Table 10.1).
Unlike previous classifications, Sandu and Monnier introduce type 0 clefts (“occult” or more accurately submucosal), which appear as a consequence of a posteriorly defective cricoid cartilage accompanied by the absence of transverse interarytenoid muscles . Type I clefts are manifest interarytenoid clefts with the absence of interarytenoid muscles which do not involve at all the cricoid cartilage. Type II clefts extend partially through the cricoid cartilage. By definition, type III and type IV clefts extend above and below the thoracic inlet, respectively. Sandu and Monnier’s classification pays particular attention to two specific features in these severe forms of disease: (1) whether the cricoid plate is partially or completely involved by the LTC in type III clefts and (2) whether the cleft is supra- or infracarinal in type IV LTCs (Fig. 10.1).
LTC classification according to Sandu and Monnier
10.2.2 Clinical Presentation
The classical diagnostic triad of LTC consists of husky cry, aspiration pneumonia, and swallowing disorders in a newborn child with associated congenital anomalies . While such scenario should immediately prompt active search for LTC, disease spectrum can often complicate and delay LTC diagnosis. Indeed, LTCs are congenital laryngotracheal disorders which can present as submucosal closure defect in the mildest cases versus complete laryngotracheoesophageal clefts (LTEC) in some other severe cases. Breathing difficulties are typically due to prolapsing of retroarytenoid mucosa caused by the absence of the aerodigestive party wall and obstruction of the posterior respiratory glottis (Fig. 10.2). Therefore, presenting signs and symptoms related to LTC may vary depending on disease severity [7, 8].
Airway obstruction secondary to arytenoid prolapse and mucosal invagination into the trachea
LTCs without involvement of the posterior cricoid plate (type 0 and I) may be asymptomatic or in the case of type I clefts present with mild occasional episodes of aspiration, hoarse cry, aspiration, cough, or in some cases dyspnea or cyanosis during feeding [8–10]. Due to their rarity, diagnosis of type 0 and I clefts requires a high-suspicion index.
Regarding clefts with cricoid (with or without tracheal involvement), the outstanding issue is severe aspiration and subsequent lower pulmonary tract infection, as well as respiratory problems in some cases [9, 11]. Finally, type IV LTCs have a dim prognosis due to respiratory distress, poor airway tone, and difficulties to maintain a patent airway even when using invasive procedures [11–13]. Table 10.2 summarizes the clinical presentation of LTCs .
Clinical presentation of LTCs
Salivary stasis in the pharynx
10.2.3 Radiologic Studies
While the mainstay of LTC diagnosis is endoscopic (discussed below), some imaging exams may be contributive. Plain chest X-ray is often performed in children with persistent respiratory symptoms, whether or not such symptoms are secondary to an underlying LTC. Patients with LTC may present aspiration pneumonia or peribronchial cuffing, but chest X-ray is normal in up to 25 % of type I and around 10 % of type II LTCs .
Modified barium swallow (MBS) performed under the supervision of a speech and swallowing pathologist, testing diverse food consistencies, may help identifying patients with discoordinated swallow or aspiration. It has been previously pointed out that aspiration in an otherwise healthy child most often correlates with an underlying anatomic abnormality .
It is important to keep in mind that children with an undiagnosed LTC presenting with swallowing disorders may have undergone several MBSs in the past, and the cumulative radiation dose can be substantial.
10.2.4 Functional Endoscopic Evaluation of Swallowing (FEES)
FEES provides an extremely accurate dynamic assessment of the laryngeal function during swallowing. FEES is usually possible in children older than 1 year but is otherwise difficult to perform in younger children. During FEES, several food consistencies should be tested. Hypopharyngeal stasis and/or laryngeal penetration may be visualized in cases of early-stage LTCs .
Like MBS, FEES can be normal in children with grade I cleft with only intermittent aspiration.
10.2.5 Endoscopic Diagnosis
Definitive LTC diagnosis relies on endoscopic examination. Due to the high incidence of associated malformations, complete endoscopy of the upper aerodigestive tract is mandatory, and should include:
Transnasal fiberoptic laryngoscopy, performed with the patient under spontaneous breathing. The entire airway is examined dynamically from the nostrils to the bronchi. The glottis ought to be sprayed with local anesthesia in order to examine the lower airway. In case the child bears a tracheotomy, the canula is removed intermittently during ventilation to facilitate comprehensive dynamic airway examination. Typically, LTC is associated with varying degrees of tracheobronchomalacia due to the absence of the trachealis muscle.
Direct laryngoscopy and esophagoscopy:
Laryngoscopy must be performed using an anesthesia Macintosh spatula as well as 0°, 30°, and 70° telescopes, prior to airway intubation.
Suspension laryngoscopy in order to evaluate the morphology of the glottis and assess the posterior commissure using a Lindholm vocal fold retractor allows the diagnosis of a submucosal or small type I cleft. Palpation of the interarytenoid region using a blunt probe is the hallmark to the diagnosis of an LTC (Fig. 10.3). The probe dips down into the posterior commissure in the presence of a cleft. The lower limit of the probe and simultaneous visualization by a telescope gives an idea regarding the cleft depth and thus its type.
The use of a blunt-angled probe to diagnose an LTC
Associated airway findings in LTC include:
Narrowed interarytenoid distance with prolapsing retroarytenoid mucosa that blocks the posterior respiratory glottis
Paramedian position of the vocal folds
Mucosal cobblestoning (secondary to gastroesophageal reflux)
The therapeutic approach to the child with LTC largely depends on the extent of the cleft, severity of clinical manifestations, and associated or underlying disorders. All decisions should be taken in consultation with the parents and in the context of a multidisciplinary team, especially in children with severe comorbidities (such as cardiac, respiratory, etc.). In symptomatic patients, within the period between diagnosis and eventual surgical management, two issues stand out: respiratory and swallowing disorders.
Type 0 and I LTCs without respiratory symptoms may benefit of regular follow-up and eventually prophylactic-intermittent antibiotherapy in order to prevent pulmonary complications of recurrent pneumonia. Most of these patients are likely to require surgery at some point in their lives for chronic intractable aspiration. Type II clefts present with feeding difficulties and quasi-systematically require surgical management. Type III and type IV LTCs may quickly degrade from a respiratory point of view, imposing oxygen therapy and pharyngeal aspiration tubes. The degree of invasiveness of oxygenotherapy may vary from nasal administration of oxygen to invasive ventilation (i.e., endotracheal tubes and even tracheostomy).
With respect to swallowing disorders, measures to avoid tracheobronchial aspiration and GERD must be considered a priority. Tracheobronchial aspiration in advanced-type LTCs represents a serious and immediate threat to the vital prognosis and consequently requires aggressive management approaches. More specifically, LTCs of type I and II require medical anti-GERD treatment and thickened food. More severe cases may impose suspension of oral feeding and enteral administration through a nasal or a gastrostomy tube, or even parenteral nutrition in case of longer clefts.
In summary, even though the management of LTCs is far from being consensual, there is some agreement that children with type I clefts may benefit from a trial of medical management and regular follow-up, while longer clefts (with cricoid involvement) require early surgical approaches to avoid the pulmonary complications of aspiration [7, 15, 17, 19]. Furthermore, a minimally invasive endoscopic approach has become standard for the management of types I, II, and IIIa (and even selected IIIb) LTCs, while major types IIIb and IV clefts most often require open approaches [2, 15, 20–22]. Open approaches are equally indicated as salvage for failed attempts of endoscopic repair.
10.3.1 Endoscopic Repair
Since the late 1970s, various endoscopic approaches have been successfully used primarily for types I and II clefts . Injection laryngoplasty using different products (Gelfoam, bioplastic) has been reported [26, 27]. Endoscopic repair has progressively become the standard of care for types I and II clefts that remain symptomatic despite adequate medical treatment after an observation period of 4–6 months [14, 16, 17].
Sandu and Monnier reported a small series of patients with types IIIa and IIIb LTCs managed endoscopically . In their reported experience carbon dioxide laser is used in ultrapulse mode to incise the cleft from caudal to cranial direction – cleft apex up to the cuneiform cartilages. The CO2 laser is a precise cutting tool giving a bloodless field and causes no mucosal charring. Two layers of mucosae are created: laryngotracheal and pharyngoesophageal. Starting caudally, a set of inverted Vicryl 5.0 sutures are placed on the tracheal aspect of the cleft and the knots tied facing the pharyngoesophageal side. The second mucosal layer is sutured in similar fashion in distal to proximal direction with knots facing the esophagus while gradually withdrawing the suspension laryngoscope (Fig. 10.4). The procedure is performed under spontaneous respiration and without endotracheal intubation. At the end of the procedure, it is important to maintain an adequate posterior commissure and avoid posterior glottic stenosis (Fig. 10.5). Special endoscopic suturing instruments are a must and their role needs emphasis. The details of such instruments are described in related articles .