-
-
- Abnormal opening or fissure in an anatomical structure
- Usually a congenital malformation due to abnormal fusion of parts during embryological development
- Can be due to ablative surgery
What Is a Cleft?
Cont’d
Clefts:
Vary in type and severity
Follow embryological suture lines (along raphe?)
-
-
- Embryological development is dependent on formation of neural crest cells in embryo.
- Neural crest cells are found between the neural tube and the epidermis of an embryo.
- Cells migrate to form skull and face. (should happen 5-6 wks - if not, wont happen ever?)
-(incisive foramen - birthplace - clefting starts away from it?)
-
- Genetic or environmental factors delay cell migration and palatal shelf movement.
- This can cause the embryo to miss the period of epithelial cell fusion.
Causes of Clefts
Multifactorial Inheritance
- Endogenous (internal) factors
- –Chromosomal disorders
- –Genetic disorders
- Exogenous (external) factors (e.g., teratogens)
- –Drugs: phenytoin (Dilantin), valium, and corticosteroids
- –Viruses (rubella, influenza)
- –Teratogens (smoking, lead)
- –Nutritional deficiencies or maternal obesity
- –Mechanical interference
-
-
- Lip (primary palate) begins at 7 weeks.
- Palate (secondary palate) begins at 9 weeks.
- Development is independent. - can have one OR the other
Embryological Development
- Embryological closure begins at incisive foramen and “zips” …
- –forward to form the alveolar ridge and then lip
- –backward to form the hard palate and velum
-
-
- Clefting severity occurs from…
- –the lip in to the incisive foramen
- –the uvula in to the incisive foramen
- Right side of lip may close first.
- Oral surface of velum may close first.
Classification of Clefts - primary - - - -
Primary Palate (Cleft Lip)
- Fuses around 7 weeks of gestation
- Anterior to incisive foramen
- Includes lip and alveolus
- Clefts include:
- –Complete or incomplete
- –Unilateral or bilateral
Classification of Clefts - secondary - - - -
Secondary Palate (Cleft Palate)
- Fuses around 9 weeks of gestation
- Posterior to incisive foramen
- Includes hard palate and velum
- Clefts include:
- –Complete or incomplete
Clefts of the Primary Palate: Types and Severity - - - - -
-Unilateral incomplete cleft lip
-Unilateral complete cleft lip
-Bilateral incomplete cleft lip
-Bilateral complete cleft lip
-Simonart’s Band—band of soft tissue that bridges a cleft of the lip
May be due to amniotic bands
-
Clefts of the Primary Palate: Effects on Structure and Function
- Structure
- –Cleft lip and orbicularis oris
- –Wide, flat nose with spreading nasal ala
- –Short columella
- –Abnormal dentition
- Function
- –Specific articulation errors
- –Resonance affected
Clefts of the Secondary Palate: Types and Severity - - - -
- cleft palate
- Cleft palate with Pierre Robin sequence
- Bilateral complete cleft lip and palate
- Palatal (oronasal) fistula
Clefts of the Secondary Palate: Effects on Structure and Function
- Structure
- –Absent velar aponeurosis
- –Altered insertion of the levator velar muscles (cleft muscles of Veau)
- –Abnormalities in nasal septum
- Function
- –Velopharyngeal insufficiency (speech and resonance affected)
- –Feeding problems and nasal regurgitation
- –Eustachian tube malfunction
-
- Overt—visible from the oral surface
- Occult (hidden)—normal on the oral surface, abnormal on the nasal surface
Submucous Cleft Palate: Types and Severity - - - -
Classic stigmata of an overt submucous cleft:
- Bifid or hypoplastic (small and underdeveloped) uvula
- Zona pellucida—thin, bluish area in middle of the velum
- Notch in the hard palate where the posterior nasal spine should be, if the submucous cleft extends that far
- Muscles often affected in the same way as a complete cleft palate
Submucous Cleft Palate: Types and Severity
- Affects interdigitation of the levator veli palatini muscle
- Levator muscle inserts on the posterior border of hard palate rather than in the middle of the velum
Submucous Cleft: Effects on Structure and Function
Depends on the extent
- May have virtually no effect
- May have the same effects as an overt cleft palate as follows:
- –Structure
- Altered insertion of the levator velar muscles (cleft muscles of Veau)
- –Function
- Velopharyngeal insufficiency (speech and resonance affected)
- Feeding problems and nasal regurgitation
- Eustachian tube malfunction
Clefts of the Primary Palate: Types and Severity
Midline cleft with holoprosencephaly
-Holoprosencephaly—failure of the prosencephalon (the embryonic forebrain) to divide into double lobes of the cerebral hemispheres. The result is a single-lobed brain structure.
Facial Clefts: Type and Severity
- causes
- two types
-Can be caused by:
Genetic defects
Amniotic bands
-Two types of facial clefts:
Oblique
Midline (median)
Facial Clefts: Effects on Structure and Function
-Structural abnormalities on the outside the head (face or skull) usually suggest abnormalities on the inside of the head (face or skull).
-Abnormalities on the inside the head (face or skull) usually affect function of the following: cognition language speech resonance hearing feeding/swallowing
Prevalence of clefts
Cleft lip occurs twice as often in males (with/without cleft palate).
Cleft palate occurs twice as often in females.
prevalence of clefts
- Submucous cleft
- -Essentially unknown
- -May not cause problems with speech
- -May become symptomatic after adenoidectomy
- Facial cleft
- -Very rare
-
-
- Cheiloplasty to close the lip
- Palatoplasty to close the palate
- Usually pharyngeal flap or sphincter pharyngoplasty if there is velopharyngeal insufficiency affecting speech
