Cleft lip and cleft palate are both congenital birth defects that occur when there is abnormal formation of the foetus’ lip or mouth during the pregnancy. They are together known as orofacial clefts.
Pathophysiology
The external face develops between week 4-6 of embryonic development. Between week 6-8 the palate begins to develop. The development of the palate creates a division between the nasal and oral cavities. This process is known as palatogenesis. Palatogenesis completes by the 12th week.
During week 3 the oropharyngeal membrane (stomodeum) begins to appear at the site of the face. This membrane begins to break down to become the future oral cavity. It sits at the beginning of the digestive tract.
The structures involved in the development of the nose and face are the pharyngeal arches as well as the neural crest cells:
- Neural crest cells - they proliferate and form the frontonasal prominence.
- Pharyngeal arches - specifically the 1st pharyngeal arch. It forms the mandibular and maxillary prominences. The stomodeum lies between the 2 maxillary processes.
As the maxillary prominences expand medially, the nasal prominences are pushed towards the midline. The maxillary prominences then fuse with the nasal prominences and soon after they fuse to form a continuous structure.
As the nose forms, the fusion of the medial nasal prominences form an intermaxillary segment. This segment is what forms the primitive palate.
The maxillary prominences expand medially to form the palatal shelves. They continue to advance medially before fusing superior to the tongue. Simultaneous development of the mandible occurs. The mandible expands to increase the size of the oral cavity. The palatal shelves fuse together in the horizontal plane. In the vertical plane they fuse with the nasal septum. This is what is known as the secondary palate.
- Cleft lip occurs when the medial nasal prominence and maxillary prominence fail to fuse.
- Cleft palate occurs when the palatal shelves fail to fuse in the midline. It may occur in isolation or in combination with a cleft lip.
The actual aetiology behind the abnormalities are unknown. It is believed to be due to a combination of genetic predispositions and environmental factors.
⚠️ Risk factors
- Smoking
- Diabetes
- Medications - certain antiepileptic drugs such as topiramate and valproic acid have been associated with an increased prevalence of cleft lip if used within the first 3 months.
- Certain syndromes are associated with clefts:
- Pierre Robin sequence - this is a rare congenital birth defect characterized by an underdeveloped jaw, backward displacement of the tongue and upper airway obstruction. Cleft palate is also commonly observed.
- Stickler syndrome - a relatively common connective tissue disorder leading to orofacial abnormalities, hearing loss, ocular issues and skeletal issues such as arthropathy and joint hypermobilIty.
- Van der Woude syndrome - rare genetic disorder characterized by various structural deformities of the mouth. Characteristically there are lower lip pits combined with a cleft lip (with or without cleft palate), or cleft palate alone
- DiGeorge syndrome (22q11 deletion) - a genetic disorder characterized by a variety of symptoms including cleft palate, heart defects, facial abnormalities, and immune system deficiencies.]
🔢 Classification
Cleft lip may occur with/without cleft palate. Cleft palate may be unilateral or bilateral.
The commonality of variants are as follows:
- Combined cleft lip and palate - 45%.
- Isolated cleft palate - 40%.
- Isolated cleft lip - 15%.
🔍 Investigations
A diagnosis may be made via routine ultrasound during pregnancy. It can also be diagnosed after the baby is born on clinical examination. Assessment for a cleft palate is much easier however, a cleft palate may be not as overt.
💡 It is important to assess for a cleft palate during a newborn and infant physical examination (NIPE).
🧰 Management
The baby should be referred to local cleft service. This service contains an MDT of specialists, such as:
- Specialist nurses
- Plastic, maxilofacial and ENT surgeons
- Dentists
- Speech and language therapists
- Psychologists
- General practitioners
🥇The first priority is to ensure the baby can eat and drink. This may involve the use of special bottles/teats. The specialist nurses will follow the child through surgery and beyond to ensure they are developing appropriately.
🏆 The definitive management of orofacial clefts is through surgical repair:
- Cleft lip surgery - is usually performed at 3 months.
- Cleft palate surgery - is usually performed at 6-12 months.
Many children will need additional surgical procedures as they age, especially if it is not an isolated orofacial cleft.
🚨 Complications
- Feeding problems
- Psychosocial implications
- Impaired speech - children can receive speech therapy which helps to attain normal speech in the majority of cases.
- Otitis media with effusion and hearing impairments - children with cleft palate commonly have middle ear issues and associated hearing loss. This is because the muscles of the palate are vital to allow air into the middle ear as well as allowing drainage of secretions from the middle ear. If interrupted, it can lead to infection and effusion - otitis media with effusion (OME). OME leads to temporary hearing loss which is mild in severity. If left untreated it can lead to permanent hearing loss.