Introduction

Frontonasal dysplasia is a rare disorder marked by atypical development of the head and face during prenatal stages. Major physical features could be a broad, flat nose, a vertical groove running down the middle of the face, or widely spread eyes (ocular hypertelorism). The vertical groove's breadth and depth might differ significantly. In more extreme situations, the nose may split vertically into two halves; in other cases, the tip may be removed. In some cases, there may be an unusual skin-covered gap at the front of the head, referred to as anterior cranium occultum.¹

It is uncommon for kids with FND to go through their childhood undetected and/or untreated because the majority of people with the condition exhibit characteristic signs at a young age. Although the exact cause of the condition is uncertain, it appears to be related to abnormal nasal capsule development during the embryonic phase.²

Based on genetic origins and symptoms, frontonasal dysplasia can be classified into at least three categories:¹

• FND-1 is due to mutations in the ALX3 gene
• FND-2 is due to mutations in the ALX4 gene
• FND-3 is due to mutations in the ALX1 gene

Challenges in Airway Management

There are many challenges in managing the airway in patients with craniofacial abnormalities. Anesthesiologists need to understand the normal anatomy of the airway's soft tissues and bony structures, as well as how various congenital conditions can alter these features. Additionally, they must be aware of the potential complications that can occur throughout different phases of care, including preoperative evaluation, intraoperative management, and postoperative recovery.³

70% of newborns with frontonasal dysplasia are unable to breathe through their mouths independently, making them obligate nasal breathers from birth. In these patients, the 

extent of airway obstruction is dynamic, and severity fluctuates as the soft tissues and craniofacial skeleton grow. During childhood, partial or complete airway blockage can occur at any time.⁴

When examining a child's airway, common challenges include an unwilling child and the unreliability of the Mallampati grading system in predicting a child's difficult airway. In addition to the more particular airway problems linked with each disease and other related organ involvement, airway assessment has to concentrate on the general clinical systematic examination. A physical examination, diagnostic testing, and taking a history should all be part of the process.⁵

Although they are uncommon, major airway management problems have the potential to be among the most fatal in medical history. For instance, less than 1 in 5000 normal general anaesthetics result in the "can't intubate, can't ventilate" (CICV) scenario, which accounts for up to 25% of anaesthesia-related mortality and requires an emergency surgical airway (ESA) in approximately 1 in 50 000 cases.⁶

A prospective registry was incorporated in the 4th National Audit Project of the Difficult Airway Society and the Royal College of Anaesthetists (NAP4) for the voluntary reporting of significant airway management difficulties over 12 months. For the management of aspiration, hypoxia from post-obstructive pulmonary oedema, failure to awaken following surgery, myocardial ischaemia, or cardiac arrest, ICU admission was an inclusion criterion in 100 anaesthesia patients. Out of these patients, 81 recovered fully, 7 recovered partially, and 12 died.⁶

Strategies for airway management

Managing the airway in infants and children with difficult airways can be complex, with several suggested approaches but no standardised algorithm like the American Society of Anesthesiologists (ASA) adult difficult airway algorithm. Awake intubation has largely fallen out of favour for pediatric patients, except in certain emergencies where the child is in severe distress or has a significant airway obstruction. The reason for this shift is due to the disadvantages of awake intubation, such as increasing intracranial pressure (ICP), risking intracerebral haemorrhage (ICH), gagging, and the difficulty of managing an uncooperative child. As a result, inducing anaesthesia while maintaining spontaneous breathing is the key strategy in safely managing the airways of children with craniofacial syndromes, where a difficult airway is suspected.⁵

A clear and structured airway management plan is essential. It's common practice to have a "Plan A" for the initial approach, along with backup plans (Plan B and C) in case of failure. Having an otolaryngologist on hand for emergency surgical access, such as bronchoscopy or tracheostomy, is recommended when managing difficult airways. Additionally, securing a peripheral IV line before anaesthesia induction is advised in children with craniofacial 

anomalies, and it's best to have two pediatric anesthesiologists present during the induction phase.⁵

Plan A: Preserve spontaneous ventilation⁵

Anaesthesia can be induced with IV sedatives, such as propofol (either as an infusion or boluses), dexmedetomidine, or ketamine. Alternatively, inhalation induction with sevoflurane is another option. As long as the patient is breathing spontaneously, the laryngoscope blade can be carefully inserted, provided the child tolerates the procedure without coughing or moving abruptly.

There are many different airway tools and techniques available for intubation, but the provider must use the tools they are most comfortable with. It's also important to remember that a tool is not a plan in and of itself.

Techniques for intubating children with syndromic difficult airways:

• Direct laryngoscopy: A standard laryngoscope blade, such as a Macintosh (curved) or Miller (straight) blade, can be used. The paraglossal approach with a straight blade is a well-established technique for difficult pediatric airways, particularly when standard laryngoscopy fails. This technique allows the provider to bypass the large tongue often present in craniofacial syndromes by inserting the blade between the tonsils and the base of the tongue. While this approach can provide better exposure of the anterior larynx, it limits space for tube manipulation, requiring advanced skill. Direct laryngoscopy may also be facilitated by using a gum elastic bougie or a stylet
• Video laryngoscopy: Devices such as the Storz video laryngoscope or the Glidescope have been successfully used in syndromic children with difficult airways. Although the Glidescope offers a good view, the intubation process can be challenging due to the limited working space and the airway's curvature, particularly in smaller children
• Fiberoptic bronchoscopy (FOB) intubation: This is a popular option as either a first-line technique or a fallback when direct laryngoscopy or other methods fail. FOB intubation can be performed nasally, orally, or through a laryngeal mask airway (LMA). However, it's not always an option for neonates and small infants, as the smallest endotracheal tubes may barely accommodate the smallest fiberoptic scopes. In addition, the narrow field of vision in neonates' small airways increases the risk of obstruction when the scope touches surrounding structures, requiring significant expertise
• FOB through an LMA: This is another common technique for children with difficult airways. The LMA facilitates ventilation and oxygenation during intubation, making it especially beneficial when bag-mask ventilation is difficult. However, removing the LMA after intubation can risk accidentally dislodging the endotracheal tube. To prevent this, some recommend leaving both the LMA and ETT in place until extubation
• Fiberoptic bronchoscope + Glidescope: In this technique, the fiberoptic bronchoscope acts as a guide for intubation while the Glidescope provides visual assistance. This requires two 

providers: one to manage the Glidescope and the other to handle the bronchoscope. This combination is called the video-assisted fiberoptic intubation (VAFI) technique.

Plan B⁵

If Plan A fails and ventilation becomes difficult, the next step is to insert an LMA. If bag-mask ventilation becomes possible after the LMA is in place, the provider may choose to leave the LMA in place for the procedure or proceed with fiberoptic intubation through the LMA. If ventilation is not possible through the LMA, it's time to move to Plan C.

Plan C⁵

If both bag mask and LMA ventilation fail, a single attempt at direct laryngoscopy may be made. If all other attempts are unsuccessful, an emergency surgical airway is required. In this case, the otolaryngologist should perform a rigid bronchoscopy or an emergency tracheostomy.

Extubation and post-extubation care⁵

Extubation should be carried out only at the end of the procedure if:

• Intubation was smooth and without significant airway trauma or swelling
• The surgery was minor and did not involve the airway
• There is no history of severe obstructive sleep apnea

The patient should be fully awake, breathing independently, and have regained their airway reflexes before extubation. The anesthesiologist must be prepared to reintubate if the extubation attempt fails.

Children with conditions like obstructive sleep apnea should be monitored in a high-dependency unit overnight with apnea monitoring. Those who have undergone major airway surgeries, such as mandibular distraction, or experienced difficult intubations should remain intubated postoperatively. These patients are at higher risk of post-op airway obstruction due to swelling, which could make re-intubation extremely difficult. They should be transferred to the ICU, kept sedated, and given IV steroids to reduce airway swelling.⁵

Summary

Frontonasal dysplasia (FND) is a rare birth defect affecting facial and head development, with features like a broad, flat nose, widely spaced eyes, and sometimes a split nose or skull gap. It’s usually diagnosed early due to visible signs. The condition is linked to abnormal nasal development during pregnancy and has three types, each caused by different genetic mutations (ALX3, ALX4, ALX1).

Airway management in children with FND is challenging due to difficulties in ventilation and intubation. Careful planning, backup strategies, and maintaining spontaneous breathing are essential. Extubation should be done cautiously, with close monitoring afterwards to prevent airway issues.