Craniofacial Clefts

Craniofacial Cleft Definition

Craniofacial clefts is an umbrella term that encompasses a wide of soft-tissue and bone deformities. It is a type of craniofacial deformity defined by the American Society of Cleft Lip and Palate.

They can be sub-defined based on the anatomical location:

• Oral-Nasal: Clefts 0-3
• Oral-Ocular: Clefts 4-6
• Lateral Facial: Cleft 7-9
• Cranial: Clefts 10-14

Craniofacial Cleft Pathogenesis

Craniofacial clefts are "atypical clefts" that occur due to two theories

1. "Classic": failure of fusions of the facial prominences
2. Mesodermal penetration: failure of mesodermal penetration results in unsupported epithelial walls that dehisce

These occur sporadically, but specific environmental factors have been identified:

• Exposure: radiation, vitamin A derivatives
• Maternal: infection (CMV, toxoplasmosis), diabetes, weight, folic acid deficiency.

Tessier Classification of Craniofacial Clefts

Tessier Classification is an anatomical classification of craniofacial clefts. A number is assigned to each malformation according to its position relative to the midline.  

Tessier classification is the most commonly used for Craniofacial clefts.

• Benefit: easily correlate anatomical defects and required reconstruction
• Limitation: purely descriptive and does not denote causation  

1. All clefts are numbered from 0-14
2. Midline clefts are number 0
3. Facial clefts are numbered out laterally from 1-7 inferior to the orbit
4. Cranial clefts are numbered in medially from 8-14 superior to the orbit.
5. Facial and Cranial clefts can be connected.

Some tips can be used to help remember Tessier Classification. These are illustrated below in the table.

Craniofacial clefts can be groups based on their location. There are 4 main groups.  

• Oral-nasal clefts are Tessier Clefts 0-3 between the midline and cupid's bow. This results in clefts involving the midline structures (lips and nose).
• Oral-Ocular clefts are Tessier Clefts 4-6 that occur between oral and orbital cavities without disrupting the nose.
• Lateral Facial clefts are Tessier Clefts 7-9, resulting in Treacher Collins Syndrome, hemifacial microsomal, and necrotic facial dysplasia.
• Cranial Clefts are Tessier clefts 10-14 that occur in the frontal and cranial vault.

Individual Craniofacial Clefts

Cleft Number 0

• A cleft spectrum of deficient or excess midline structures.
• Deficiency leads to hypotolerism; excess leads to hypertelorism.  
• Can continue as cleft number 14
• Incomplete merging of the median nasal prominences in the midline

Cleft Number 1

• Nasal dysplasia has a pattern similar to cleft lip and palate.
• Lateral margin of cupid's bow and between the central and lateral incisors.
• Can continue as cleft number 13

Cleft Number 2 (Rare)

• Hypoplastic nasal ala,  flattened nose, displaced medial canthus
• The lacrimal duct is not involved  
• Can continue as cleft number 12

Cleft Number 3 ("Common")

• Between the lateral incisors and canine
• Superiorly based alar and short nose
• The lacrimal system involved + colobomas of the lower eyelid.  
• Can continue as cleft 10 or 11

Cleft Number 4:

• Lateral to cupid's bowel and nasal ala
• Ascend around the alar base, along the nasomaxillary junction, and across the tear duct and medial orbital tissues.
• Unilateral or bilateral
• Colobomas but intact medial canthal ligament.

Cleft Number 5 (Rarest)

• Lateral to canine and infraorbital foramen
• Medial to the oral commissure
• Extends through the maxillary sinus to the orbital floor
• Abnormal sphenoid wing (agenesis linked to neurofibromatosis)

Cleft Number 6

• Forms part of Treacher Collins Syndrome
• Normal Ear
• Zygomaticomaxillary cleft

Cleft Number 7 (Most Common)

• The middle ear, zygoma, maxilla and mandible affected
• Variable expression of macrostomia and hypoplasia of the zygoma.
• Trigeminal and facial nerves are involved.
• Caused by disruption of the stapedial artery during embryogenesis
• Centred in the region of the zygomaticotemporal suture
• Associated with a duplicate maxilla, supernumerary teeth
• Occur in isolation or more commonly with craniofacial/hemifacial microsomia.

Cleft 8 (Rare in Isolation)

• Primarily involves the orbital area
• Lateral commissure coloboma and lateral canthus absence
• Associated with Goldenhaar Syndrome

Cleft Number 9 (Rare)

• Involves the upper eyelid and brow
• The temporal branch of facial nerve palsy
• Associated with encephaloceles.

Cleft Number 10

• Involvement of middle orbital area and cranial base
• Link to hypertelorism
• Proptosis with fronto-orbital encephalocele may be present
• Can be an extension of cleft number 4

Cleft Number 11

• Involvement of upper medial eyelid (not cranial base)
• Link to encephalocele & hypertelorism (pneumatisation of ethmoid cells)
• Can be an extension of cleft number 4

Cleft Number 12

• Laterally displaced medial canthus and frontal hairline projected downward
• Hypertelorism and telecanthus
• Involved frontal and sphenoid sinuses

Cleft Number 13

• Paramedian frontal encephalocele
• V-shaped hair
• Dystopia and hypertelorism

Cleft Number 14

• A spectrum of deficiency to excess
• Involves CNS abnormalities
• Can see herniation of intracranial contents.

Cleft Number 30

• Bifid tongue
• A notch on the lower lip
• Issues with hyoid bone and thyroid cartilage

Management of Craniofacial Clefts

Principles

The management of craniofacial clefts is centred on a multi-disciplinary team. The goal of treatment is to restore function, cosmesis and normal anatomical alignment of structures and cavities.

Critical aspects of the management focus on:

1. Eyes: Eyelid reconstruction to prevent globe exposure
2. Mouth: functional correction of macrostoma
3. Cavities: recreate separations between nose, mouth and orbits.

Techniques

To achieves these goals, a myriad of techniques is available. These include:

• Distraction Osteogenesis
• Bone grafting
• Alloplastic implants
• Tissue Expansion
• Flap Reconstruction

Flashcards