**4. Craniofacial anomalies and airway management**

#### **4.1 Down's syndrome**

*Overview*: Down's syndrome is the leading chromosomal disorder associated with intellectual disability worldwide. It is characterized by a bundle of multisystemic morphologic features including cardiovascular, pulmonary, gastrointestinal, neurological, musculoskeletal, hematological, immunological, endocrine, ophthalmic, and hearing abnormalities. It was firstly described and published in the London Hospital Reports by a British doctor John Langdon Down in 1866 who called it "Mongolian type."

*Genetics*: Down's syndrome is a congenital autosomal disorder caused by the existence of a third copy, full or partial, of the chromosome 21 (HSA21), usually by nondisjunction [8].

*Incidence*: its average incidence is estimated to be about 1 in 800 live births and tends to increase with advanced maternal age.

*Pathophysiology*: This syndrome is caused by the existence of a third copy (either full or partial) of the chromosome 21 (HSA21) [8].

*Clinical considerations*: Down's syndrome is a multisystem disease associated with generalized growth retardation and varying degrees of mental impairment. Its clinical hallmarks encompass generalized neuromuscular hypotonia, atlantoaxial instability often associated with congenital cardiac anomalies (in particular an atrioventricular septal defect, a patent ductus arteriosus, or a tetralogy of Fallot) and gastrointestinal malformations (duodenal atresia and Hirschsprung disease) [4, 5, 9]. In addition, children with DS compared to healthy ones are more prone to multiple health issues, including obstructive sleep apnea, recurrent infections, hypothyroidism, epilepsy, audiovestibular and visual impairment, hematopoietic disorders (including leukemia), anxiety disorders, and early-onset Alzheimer disease. The physical appearance is pathognomonic with a chunky stature and a small round dysmorphic face.

In 1866, Dr. John Langdon Down, with few simple words, well described the main craniofacial features related to this disorder: a flat and broad face, narrow palpebral fissures, small nose, and long and thick tongue. These anomalies include a microcephaly, brachycephaly, a flattened occiput, a sloping forehead, midfacial hypoplasia, depressed nasal bridge, slanting eyes with epicanthic folds, hypotelorism, strabismus, and small ears with flat or absent helix. A cleft lip and/or palate may be present.

*Airway and anesthetic implications*: airway obstruction is common in children with Down's syndrome. A midface hypoplasia, narrow nasopharynx, choanal stenosis, high arched palate, pharyngeal muscle hypotonia, relative macroglossia, lingual tonsils, glossoptosis, adenotonsillar hypertrophy, micrognathia, short broad neck, and obesity, all these anatomical conditions combined together contribute to upper airway narrowing [6, 10]. In addition, various other structural airway anomalies may be present and diminish further the airway volume. They may be found isolated or combined together such as: laryngomalacia, subglottic stenosis, congenital tracheal, and bronchial anomalies [11]. They are highly suspected in children with Down's syndrome who have recurrent respiratory symptoms. Laryngomalacia and obstructive sleep apnea syndrome are the most common cause of upper airway obstruction below and above the age of 2 years old, respectively. Obstructive sleep apnea syndrome is reported with an incidence of approximately 30–55% of children with Down's syndrome and may be a potential indication of an adenotonsillectomy and/or home continuous positive airways pressure ventilation (BiPAP).

**159**

*An Approach to the Airway Management in Children with Craniofacial Anomalies*

Collecting a detailed and accurate history from the parents is the first step in assessing the airways. Symptoms related to obstructive sleep apnea (snoring, choking, mouth breathing, sleep disturbances/restless sleep, diurnal drowsiness or fatigue) and a recent episode of upper respiratory tract infection should be noted. Any recent or active upper respiratory infection should prompt the physician to postpone any non-urgent surgery because of the high rate of postoperative respiratory complications. Examination of the oropharynx and head-neck is of utmost importance looking for any predictor of a difficult airway. A careful pulmonary examination is a must, and preoperative chest X-ray is not routinely required. An echocardiography is sometimes indicated to rule out any congenital heart defect or

The risk of upper airway obstruction at the induction of anesthesia for children with Down's syndrome is always present, hence a difficult airway management scenario must be anticipated. A difficult mask ventilation may necessitate insertion of an oropharyngeal or a nasopharyngeal airway. Tracheal intubation in children with Down's syndrome deserves special attention. The trachea is narrow and smaller than in healthy children, not only at the subglottic area but over its entire length and may be the site of numerous anatomical anomalies. When endotracheal intubation is indicated, a tracheal tube of 0.5 or 1 mm smaller than the expected one may be required due to the high risk of post-extubation stridor. It is recommended to monitor the ETT cuff pressure and keep it below 18 cm H2O in order to lower the risk of post-extubation stridor, whereas a smooth and non-traumatic tracheal

Craniocervical instability is reported to be common in children with DS with an incidence of about 15% of the cases, mostly secondary to a hyperlaxity of the transverse ligament. Nonetheless, a malformation of the craniovertebral junction bones may be associated. Atlanto-occipital and atlanto-axial joints are at high risk of subluxation during airway manipulation which may result in compression of the underlying spinal cord [13]. Thus, a gentle and cautious manipulation of the neck and the head is required during the airway management of children with DS especially those with potential risk of cervical spine instability causing neurological deficit or at risk of worsening while under anesthesia. A cervical spine manual inline immobilization approach must always be provided by an assistant during mask

After surgery, a "no touch technique" awake extubation with the child kept in lateral position is preferred. Down's syndrome children with a history of obstructive sleep apnea are hypersensitive to opioid effects and need to be admitted for postoperative apnea monitoring (with continuous SPO2 monitoring and a dedicated nurse) due to the high incidence of postoperative airway obstruction and hypoventilation. The use of non-invasive positive pressure support may be required for DS

*Overview*: it is one of the congenital defects associated with abnormal anatomy of the airway imposing great challenges in its perioperative management. It was initially described by a French oral surgeon "Pierre-Robin" in 1923 as a clinical triad of: micrognathia (small mandible), glossoptosis (backward retraction of the tongue), and a subsequent airway obstruction [14]. The triad may be associated with a cleft palate in 50% of cases. PRS is classified as a sequence rather than a syndrome as it is representing succession of malformation events due to a sole cause, which is the

*DOI: http://dx.doi.org/10.5772/intechopen.93426*

pulmonary hypertension [12].

ventilation and intubation.

patients with severe OSA.

**4.2 Pierre Robin sequence (PRS)**

failure in fetal mandibular development [15] (**Figure 1**).

intubation should be the rule with cuffed ETT [1].

#### *An Approach to the Airway Management in Children with Craniofacial Anomalies DOI: http://dx.doi.org/10.5772/intechopen.93426*

Collecting a detailed and accurate history from the parents is the first step in assessing the airways. Symptoms related to obstructive sleep apnea (snoring, choking, mouth breathing, sleep disturbances/restless sleep, diurnal drowsiness or fatigue) and a recent episode of upper respiratory tract infection should be noted. Any recent or active upper respiratory infection should prompt the physician to postpone any non-urgent surgery because of the high rate of postoperative respiratory complications. Examination of the oropharynx and head-neck is of utmost importance looking for any predictor of a difficult airway. A careful pulmonary examination is a must, and preoperative chest X-ray is not routinely required. An echocardiography is sometimes indicated to rule out any congenital heart defect or pulmonary hypertension [12].

The risk of upper airway obstruction at the induction of anesthesia for children with Down's syndrome is always present, hence a difficult airway management scenario must be anticipated. A difficult mask ventilation may necessitate insertion of an oropharyngeal or a nasopharyngeal airway. Tracheal intubation in children with Down's syndrome deserves special attention. The trachea is narrow and smaller than in healthy children, not only at the subglottic area but over its entire length and may be the site of numerous anatomical anomalies. When endotracheal intubation is indicated, a tracheal tube of 0.5 or 1 mm smaller than the expected one may be required due to the high risk of post-extubation stridor. It is recommended to monitor the ETT cuff pressure and keep it below 18 cm H2O in order to lower the risk of post-extubation stridor, whereas a smooth and non-traumatic tracheal intubation should be the rule with cuffed ETT [1].

Craniocervical instability is reported to be common in children with DS with an incidence of about 15% of the cases, mostly secondary to a hyperlaxity of the transverse ligament. Nonetheless, a malformation of the craniovertebral junction bones may be associated. Atlanto-occipital and atlanto-axial joints are at high risk of subluxation during airway manipulation which may result in compression of the underlying spinal cord [13]. Thus, a gentle and cautious manipulation of the neck and the head is required during the airway management of children with DS especially those with potential risk of cervical spine instability causing neurological deficit or at risk of worsening while under anesthesia. A cervical spine manual inline immobilization approach must always be provided by an assistant during mask ventilation and intubation.

After surgery, a "no touch technique" awake extubation with the child kept in lateral position is preferred. Down's syndrome children with a history of obstructive sleep apnea are hypersensitive to opioid effects and need to be admitted for postoperative apnea monitoring (with continuous SPO2 monitoring and a dedicated nurse) due to the high incidence of postoperative airway obstruction and hypoventilation. The use of non-invasive positive pressure support may be required for DS patients with severe OSA.

#### **4.2 Pierre Robin sequence (PRS)**

*Overview*: it is one of the congenital defects associated with abnormal anatomy of the airway imposing great challenges in its perioperative management. It was initially described by a French oral surgeon "Pierre-Robin" in 1923 as a clinical triad of: micrognathia (small mandible), glossoptosis (backward retraction of the tongue), and a subsequent airway obstruction [14]. The triad may be associated with a cleft palate in 50% of cases. PRS is classified as a sequence rather than a syndrome as it is representing succession of malformation events due to a sole cause, which is the failure in fetal mandibular development [15] (**Figure 1**).

*Special Considerations in Human Airway Management*

tends to increase with advanced maternal age.

full or partial) of the chromosome 21 (HSA21) [8].

**4.1 Down's syndrome**

called it "Mongolian type."

small round dysmorphic face.

palate may be present.

nondisjunction [8].

**4. Craniofacial anomalies and airway management**

*Overview*: Down's syndrome is the leading chromosomal disorder associated with intellectual disability worldwide. It is characterized by a bundle of multisystemic morphologic features including cardiovascular, pulmonary, gastrointestinal, neurological, musculoskeletal, hematological, immunological, endocrine, ophthalmic, and hearing abnormalities. It was firstly described and published in the London Hospital Reports by a British doctor John Langdon Down in 1866 who

*Genetics*: Down's syndrome is a congenital autosomal disorder caused by the existence of a third copy, full or partial, of the chromosome 21 (HSA21), usually by

*Incidence*: its average incidence is estimated to be about 1 in 800 live births and

*Pathophysiology*: This syndrome is caused by the existence of a third copy (either

*Clinical considerations*: Down's syndrome is a multisystem disease associated with generalized growth retardation and varying degrees of mental impairment. Its clinical hallmarks encompass generalized neuromuscular hypotonia, atlantoaxial instability often associated with congenital cardiac anomalies (in particular an atrioventricular septal defect, a patent ductus arteriosus, or a tetralogy of Fallot) and gastrointestinal malformations (duodenal atresia and Hirschsprung disease) [4, 5, 9]. In addition, children with DS compared to healthy ones are more prone to multiple health issues, including obstructive sleep apnea, recurrent infections, hypothyroidism, epilepsy, audiovestibular and visual impairment, hematopoietic disorders (including leukemia), anxiety disorders, and early-onset Alzheimer disease. The physical appearance is pathognomonic with a chunky stature and a

In 1866, Dr. John Langdon Down, with few simple words, well described the main craniofacial features related to this disorder: a flat and broad face, narrow palpebral fissures, small nose, and long and thick tongue. These anomalies include a microcephaly, brachycephaly, a flattened occiput, a sloping forehead, midfacial hypoplasia, depressed nasal bridge, slanting eyes with epicanthic folds, hypotelorism, strabismus, and small ears with flat or absent helix. A cleft lip and/or

*Airway and anesthetic implications*: airway obstruction is common in children with Down's syndrome. A midface hypoplasia, narrow nasopharynx, choanal stenosis, high arched palate, pharyngeal muscle hypotonia, relative macroglossia, lingual tonsils, glossoptosis, adenotonsillar hypertrophy, micrognathia, short broad neck, and obesity, all these anatomical conditions combined together contribute to upper airway narrowing [6, 10]. In addition, various other structural airway anomalies may be present and diminish further the airway volume. They may be found isolated or combined together such as: laryngomalacia, subglottic stenosis, congenital tracheal, and bronchial anomalies [11]. They are highly suspected in children with Down's syndrome who have recurrent respiratory symptoms. Laryngomalacia and obstructive sleep apnea syndrome are the most common cause of upper airway obstruction below and above the age of 2 years old, respectively. Obstructive sleep apnea syndrome is reported with an incidence of approximately 30–55% of children with Down's syndrome and may be a potential indication of an adenotonsillectomy

and/or home continuous positive airways pressure ventilation (BiPAP).

**158**

#### **Figure 1.**

*Pierre Robin sequence frontal (A) and lateral (B) facial [16].*

Infants may present with airway obstruction (stridor) and respiratory distress and may require multiple surgeries (tongue adhesion, mandibular distraction osteogenesis, or tracheostomy).

The major challenge to the anesthesiologist is managing the airway of such patients who are infamous to be difficult to bag-mask-ventilate and extremely difficult to intubate.

*Incidence*: isolated PRS prevalence can range from 1/8500 to 1/14,000 of births [15]; however, around 40–60% of the PRS cases are associated with other facial syndromes including Stickler, Treacher Collins, Velocardial, and fetal alcohol syndromes [14].

*Genetics*: the genetic etiology of isolated PRS is still debatable as some authors attribute it to "in utero" compression secondary to oligohydramnios, and others suggest its association with SOX9 and KCNJ2 dysregulation on chromosome 17. However, syndromic PRS is associated with genetic mutations such as the 22q, 11.2 microdeletion in the Velocardial syndrome and the COL2A1 COL9A1 COL11A1 mutations associated with the Stickler syndrome.

*Pathophysiology:* in all cases, PRS is the consequence of primary failure of the development of the mandible, which leads to the backward and downward displacement of the tongue (the normal tongue has no place to be accommodated in the extremely small submandibular space), consequently resulting in airway obstruction. In 50% of cases, a superiorly displaced tongue may prevent the fusion of the palatal arches leading to a cleft palate. The resulting chronic airway obstruction leads to repeated episodes of hypoxemia and hypercapnia culminating in sleep apnea, pulmonary hypertension, poor feeding, gastroesophageal reflux, and failure to thrive and chronic ear diseases.

*Preoperative considerations and airway evaluation*: multiple procedures might be needed for the child with PRS such as tongue/lip adhesion, mandibular distraction osteogenesis, tracheostomy, bronchoscopies, MRI/CT imaging, gastrostomy tube insertion, and Nissen fundoplication.

The preoperative evaluation should focus on risk factors which may contribute to difficult airway management including:

1.An extremely short hyo-mental distance of less than 1 cm (or a maxillary to mandibular discrepancy of more than 1 cm)

**161**

children with PRS.

induction.

*An Approach to the Airway Management in Children with Craniofacial Anomalies*

4.Presence of OSA (may indicate severe airway obstruction)

laryngo-tracheo-broncho malacia, chronic lung disease…)

position of the tongue) and for the presence of a co-existing "cleft palate." The presence of any associated syndrome (Stickler, Velocardial, Treacher-Collins) or any heart murmur upon physical exam should prompt a request of a preoperative echocardiography as congenital heart anomalies are not uncommon in

2.Obstruction of the airway when in supine position and the need to continuously

3.Frequent desaturations and the need to provide supplementary oxygenation

7.Co-existing pulmonary disease (secondary to reflux/recurrent aspirations,

8.Presence of reflux and feeding difficulties (nasogastric-tube dependent) [17]

*Airway management in patients with PRS*: the airway management plan of the infants and children with Pierre-Robin sequence must address the difficulties in bag-mask ventilation (BMV) and tracheal intubation [18]. The small chin may render the face mask difficult to provide a fit to seal the airway for BMV. With anesthetic induction, the backwardly placed tongue may adjoin the palate and subsequently completely block the airway rendering BMV more problematic. Insertion of a "Guedel" oropharyngeal airway (to overcome the obstruction) may not properly fit the patient because of the distorted airway anatomy, which adds

The glossoptosis and the micrognathia make the glottic opening more angled and further anteriorly displaced leading to a more anterior view with the laryngoscope. Also, the nearly absent submental space makes it impossible to accommodate the tongue during laryngoscopy which renders the view obstructed by the tongue as well as the difficulty to align the oro-pharyngo-laryngeal axes. The presence of a cleft palate may prevent proper position of the laryngoscope blade in the oro-

Despite the subglottic anatomy is usually being normal in PRS, it should be remembered that the cricothyroid space is extremely small in infants which makes emergency crico-thyroitomy an impractical option in case of the need of an emergency airway access, thus the presence of an ENT surgeon as a backup for emergency tracheotomy is recommended as an integral part of the airway management in

The main aim during anesthetic induction is to preserve spontaneous ventilation by avoiding muscle relaxants as not to "burn your bridges." This could be achieved via a careful titration of IV propofol (infusion/boluses) or through inhalation

Should the scenario of "Cannot Ventilate" occur at any moment of the airway

management in children with PRS, a backup plan of alternative ventilation/ oxygenation techniques must be imminently applied which includes first a

The airway examination must focus on taking a lateral "profile" look of the mandible, assessing for the mandibulo-maxillary discrepancy and the degree of micrognathia. As well as examining the oral cavity for the degree of glossoptosis (size and

*DOI: http://dx.doi.org/10.5772/intechopen.93426*

maintain in prone positioning

5.Presence of pulmonary hypertension

6.History of a previous failed airway

such patients.

further challenges to the BMV.

pharynx hence further complicating the view.


*Special Considerations in Human Airway Management*

osteogenesis, or tracheostomy).

*Pierre Robin sequence frontal (A) and lateral (B) facial [16].*

mutations associated with the Stickler syndrome.

to thrive and chronic ear diseases.

insertion, and Nissen fundoplication.

to difficult airway management including:

mandibular discrepancy of more than 1 cm)

ficult to intubate.

**Figure 1.**

syndromes [14].

Infants may present with airway obstruction (stridor) and respiratory distress and may require multiple surgeries (tongue adhesion, mandibular distraction

*Incidence*: isolated PRS prevalence can range from 1/8500 to 1/14,000 of births [15]; however, around 40–60% of the PRS cases are associated with other facial syndromes including Stickler, Treacher Collins, Velocardial, and fetal alcohol

*Genetics*: the genetic etiology of isolated PRS is still debatable as some authors attribute it to "in utero" compression secondary to oligohydramnios, and others suggest its association with SOX9 and KCNJ2 dysregulation on chromosome 17. However, syndromic PRS is associated with genetic mutations such as the 22q, 11.2 microdeletion in the Velocardial syndrome and the COL2A1 COL9A1 COL11A1

*Pathophysiology:* in all cases, PRS is the consequence of primary failure of the development of the mandible, which leads to the backward and downward displacement of the tongue (the normal tongue has no place to be accommodated in the extremely small submandibular space), consequently resulting in airway obstruction. In 50% of cases, a superiorly displaced tongue may prevent the fusion of the palatal arches leading to a cleft palate. The resulting chronic airway obstruction leads to repeated episodes of hypoxemia and hypercapnia culminating in sleep apnea, pulmonary hypertension, poor feeding, gastroesophageal reflux, and failure

*Preoperative considerations and airway evaluation*: multiple procedures might be needed for the child with PRS such as tongue/lip adhesion, mandibular distraction osteogenesis, tracheostomy, bronchoscopies, MRI/CT imaging, gastrostomy tube

The preoperative evaluation should focus on risk factors which may contribute

1.An extremely short hyo-mental distance of less than 1 cm (or a maxillary to

The major challenge to the anesthesiologist is managing the airway of such patients who are infamous to be difficult to bag-mask-ventilate and extremely dif-

**160**


The airway examination must focus on taking a lateral "profile" look of the mandible, assessing for the mandibulo-maxillary discrepancy and the degree of micrognathia. As well as examining the oral cavity for the degree of glossoptosis (size and position of the tongue) and for the presence of a co-existing "cleft palate."

The presence of any associated syndrome (Stickler, Velocardial, Treacher-Collins) or any heart murmur upon physical exam should prompt a request of a preoperative echocardiography as congenital heart anomalies are not uncommon in such patients.

*Airway management in patients with PRS*: the airway management plan of the infants and children with Pierre-Robin sequence must address the difficulties in bag-mask ventilation (BMV) and tracheal intubation [18]. The small chin may render the face mask difficult to provide a fit to seal the airway for BMV. With anesthetic induction, the backwardly placed tongue may adjoin the palate and subsequently completely block the airway rendering BMV more problematic. Insertion of a "Guedel" oropharyngeal airway (to overcome the obstruction) may not properly fit the patient because of the distorted airway anatomy, which adds further challenges to the BMV.

The glossoptosis and the micrognathia make the glottic opening more angled and further anteriorly displaced leading to a more anterior view with the laryngoscope. Also, the nearly absent submental space makes it impossible to accommodate the tongue during laryngoscopy which renders the view obstructed by the tongue as well as the difficulty to align the oro-pharyngo-laryngeal axes. The presence of a cleft palate may prevent proper position of the laryngoscope blade in the oropharynx hence further complicating the view.

Despite the subglottic anatomy is usually being normal in PRS, it should be remembered that the cricothyroid space is extremely small in infants which makes emergency crico-thyroitomy an impractical option in case of the need of an emergency airway access, thus the presence of an ENT surgeon as a backup for emergency tracheotomy is recommended as an integral part of the airway management in children with PRS.

The main aim during anesthetic induction is to preserve spontaneous ventilation by avoiding muscle relaxants as not to "burn your bridges." This could be achieved via a careful titration of IV propofol (infusion/boluses) or through inhalation induction.

Should the scenario of "Cannot Ventilate" occur at any moment of the airway management in children with PRS, a backup plan of alternative ventilation/ oxygenation techniques must be imminently applied which includes first a

two-handed ventilation technique with oropharyngeal/nasopharyngeal airway, and if failed, an immediate insertion of an LMA.

In case of failure of the above techniques, a laryngoscopy attempt may be tried once as to relief the obstruction done by the tongue and resumption of spontaneous breathing, or to possibly intubate. Should it fail, a prompt decision to establish an emergent surgical airway access (tracheostomy) by the otolaryngologist must be taken immediately.

If intubation was difficult and traumatic, then extubation should not be attempted at the end of the procedure, but rather the patient should be appropriately sedated/paralyzed and transferred to the ICU for post-operative care where extubation should be delayed until the patient is fully awake and has a positive leak test, along with the appropriate set up for a re-intubation in case of airway obstruction/respiratory distress.
