Cleft Palate

Etiology

Cleft palate arises from a failure of development during gestation. The primordial mouth, or stomodeum, begins to form around week four. The five facial prominences arise around the mouth: frontonasal prominence in the median, bilateral maxillary prominences, and bilateral mandibular prominences. The frontonasal prominence develops into medial and lateral nasal prominences. Over the next week, the two maxillary prominences grow toward the nasal prominences, meeting the lateral nasal prominences to develop into the nasolabial region and the medial nasal prominences to create the lip. The failure to merge around the end of week five yields a unilateral or bilateral cleft lip.

At this time, the development of the palate begins and is complete around week twelve. The medial nasal prominences fuse at the midline to form the median palatine process or the primary palate. The medial portions of the maxillary processes rotate from a vertical to a lateral position around week seven to form the lateral palatine processes, which fuse at the midline from anterior to posterior to form the secondary palate. Failure of midline fusion results in cleft palate.[1]

CL/P and CPO are found in over 200 different congenital syndromes. The most commonly discussed are CHARGE (coloboma, heart defects, atresia choanae, growth retardation, genital abnormalities, and ear abnormalities) syndrome and velocardiofacial or DiGeorge syndrome (22q11.2 deletion). Cleft palate alone is more commonly associated with other congenital anomalies, about 50%, than CL/P, about 15%. The most commonly discussed anomalies associated with CPO is the Pierre Robin sequence of micro/retrognathia, glossoptosis, and cleft palate. This sequence is most commonly seen in Stickler syndrome but is also found with Treacher Collins, Nager’s, DiGeorge, and fetal alcohol syndromes.[1][2][3]

There is significant heterogeneity in the molecular pathways associated with the development of CL/P and CPO. The pathways associated with the formation of the lip and palate include the sonic hedgehog pathway (Shh and Spry2 genes), which interacts closely with the bone morphogenic pathway (Bmp4 and Bmp2 genes), fibroblast growth factor pathways (Fgf10 and Fgf7), and TGFb receptors and ligands. Disruption of these pathways at various stages results in the variability of severity, laterality, and location of clefts.[2][4]

Further, it has been shown that there is a clear environmental impact on the development of CL/P and CPO. Material risk factors for malformation including smoking, diabetes mellitus, and gestational diabetes, and teratogen exposure (valproic acid, phenytoin, retinoic acid, dioxin, thalidomide). There is a clear familial association for CL/P, and CPO as the presence of clefts in parents and siblings also increases the risk that a subsequent child will be affected. A child of an affected parent has a 3%-4% risk of CL/P and about 6% of CPO. For parents with one affected child, the risk of another is 4%, and with two affected children, 9% for CL/P and 2% and 1%, respectively, for CPO. The risk of either increases to 14% to 17% if both a parent and a child have a cleft.[1][2][3]

Epidemiology

CL/P is the most common craniofacial defect of the newborn and the fourth most common congenital anomaly. The literature quotes a prevalence of anywhere from 1 per 1,000 to 1 per 650 live births, with Asians being twice as affected as Whites. Males are more affected than females, 2 to 1. A global study by the National Institute for Dental and Craniofacial Research, including over 7.5 million births, found a prevalence of CL/P of 6.64 per 10,000 births (including stillbirths and terminations). For cleft palate alone, the prevalence was 3.28 per 10,000. Of these, 77% were isolated, 16% had other malformations, and 7% had a recognized syndrome.[1][3][5][6]

History and Physical

Prenatal diagnosis is made by ultrasound around 18 weeks gestational age. However, it is highly dependent on ultrasound technician experience and skill. With traditional 2D ultrasound, cleft lip is more accurately detected than cleft palate. 3D ultrasound has been a significant advancement with 100% sensitivity in detecting cleft palate in a fetus that has already been diagnosed with cleft lip. Prenatal MRI is useful for further characterization of the cleft and is used when a CL/P has already been identified to evaluate for other defects, especially intracranial findings. Prenatal identification allows for parental counseling and earlier intervention.[3][7] 

After birth, cleft palate is easily diagnosed on examination of the neonate. Patient history will include respiratory distress and reflux during feeding. Feeding time is generally prolonged due to this with infant fatigue. Most infants will have difficulty with an adequate latch as well. On examination, there will be a visible palatal defect, except in cases of a submucosal cleft. These are felt on palpation as a midline defect in the hard palate.

Evaluation

After birth, neonates with CL/P will become involved with an interprofessional health care team including:[3][8]

• Pediatrics/primary clinician
• Speech therapy (SLP)
• Genetics
• Otolaryngology
• Audiology
• Social work
• Orthodontics
• Craniofacial surgery

The initial evaluation is focused on respiratory and feeding issues to ensure the infant can grow and develop appropriately until the definitive surgical repair. Neonates need to be evaluated for sleep apnea, and parents counseled on appropriate management. A trained speech therapist will need to work with parents to teach appropriate feeding techniques and provide assistive devices to improve intake and reduce infant fatigue during feeds. A variety of special bottles and nipples are available to protect the nasal passages from reflux during feeds and decrease respiratory distress. A dental evaluation should be considered as well for possible oral prosthetics to aid in feeding until surgery. It is critically important for the infant to gain weight appropriately both for development, but also to prevent delays of surgical intervention. 

Subsequent and long-term evaluations include:[1][8]

• Audiologic assessment and management of hearing deficits
• Otolaryngologic management of middle ear effusion with ventilation tubes and for assessment of obstructive sleep apnea as the child grows, including the possible need for adenotonsillectomy, turbinate reduction, and/or tongue reduction
• Speech-language assessment of feeding and language development
• Family genetic counseling and future planning
• Dental evaluation and intervention as the child’s teeth begin to present
• Psychosocial counseling for both parents and child

Treatment / Management

Definitive management of cleft palate is achieved through surgical intervention. Repair is often staged, with the lip managed first, followed by the palate. The timing of the first surgical intervention is based on the often-quoted rule of tens, “10 pounds, hemoglobin of 10, and age > 10 weeks”. There are several techniques for surgical repair of the cleft lip and palate. The most commonly utilized repairs of the lip are the Millard rotation-advancement technique for unilateral cleft lip and the Mulliken technique for bilateral. Palatoplasty for cleft palate associated with cleft lip and for cleft palate alone is performed later, at 9-15 months of age. Techniques for repair include straight line repair, the Furlow double Z-plasty, and Veau-Wardill-Kilner V-Y pushback.[9]

Preoperatively, for cleft palate associated with cleft lip, the lip is usually taped from about one week of life until surgery. This helps to reduce the size of the cleft and improve symmetry. An alternative and more aggressive measure to lip taping is nasoalveolar molding (NAM), which can lead to an improved cosmetic and functional outcome after surgery. NAM involves the placement of a prosthesis that is fitted from a maxillary impression and is worn 24 hours a day and adjusted on a weekly or biweekly basis. NAM can result in far improved nasal symmetry and alveolar alignment. However, it is a significant time and effort commitment for families, and poor compliance can significantly impact outcomes.[3][10](B3)

For very wide clefts, lip adhesion is a surgical alternative to achieve a narrower cleft at the time of repair. It is uncommonly used as it requires an additional surgical procedure. It is usually performed as early as 4-6 weeks old. Lip adhesion involves elevation of rectangular mucoperiosteal lip flaps, which are brought together medially with absorbable suture.[11]

Palatoplasty Techniques

The most critical step in any of the palatoplasty techniques is the reconstruction of the levator veli palatini muscle, which functions to elevate the palate during a swallow. Inappropriate or failure to reattach the muscle can lead to velopharyngeal insufficiency or failure of velopharyngeal closure. This results in nasal reflux during swallow and hypernasal speech.[12]

Two-flap Palatoplasty or Straight-line Repair with Intravelar Veloplasty

This technique involves the elevation of mucoperiosteal flaps off the vomer on either side of the cleft. Nasal mucosal and oral mucosal flaps are elevated anteriorly from the maxillary alveolus toward the soft palate. The medial mucosal attachments of the flap are left intact over the soft palate only. The flaps are then rotated medially and closed in a layered fashion. To recreate the levator muscle sling, the muscular attachments are elevated off the hard palate and repositioned in the midline more posteriorly at the soft palate. This technique does not lengthen a short palate.

Furlow Double Z-plasty

The Furlow palatoplasty involves Z-plasty or transposition of soft palatal muscle flaps in one layer to re-create the levator sling and transposition of mucosal flaps in a second layer to recreate the uvula. The Z-plasty technique allows for lengthening of the palate. Straight-line mucoperiosteal flaps are elevated for the closure of the hard palate cleft. 

Veau-Wardill-Kilner V-Y Pushback

This technique involves elevation of bilateral mucoperiosteal flaps involving oral mucosa in an anterior to posterior direction. The posterior attachments of the flaps remain intact. The mucoperiosteal flaps are then retroposed, or pushed back, and reapproximated at the midline. This allows for palatal lengthening. The nasal mucosal layer is closed primarily in its position and is thereby exposed on its inferior or oral aspect, to close by secondary intent.

Differential Diagnosis

Cleft palate is a straight forward diagnosis. However, it is critical to identify and rule out larger syndromes of which cleft can be one feature. 

• CHARGE syndrome
• Stickler syndrome
• 22q11 deletion syndromes
• Pierre Robin sequence
• Various chromosomal deletions or duplications

Treatment Planning

Long-term Cleft Care[1]

• Perinatal: Genetic counseling, SLP counseling for feeding, lip taping, or NAM
• 0-6 months: Hearing evaluation and possible ventilating tubes placement, feeding and growth managed by SLP and primary clinician, cleft lip repair by a cleft surgeon
• 9-12 months: Palate repair, ventilating tube placement
• 1-4 years: Close follow-up for language development, dental evaluation
• 4-6 years: Evaluation for palate revision/speech surgery, columellar lengthening/nasal tip revision
• 6-12 years: Alveolar bone grafting, orthodontic intervention
• > 12 years: Definitive rhinoplasty and orthognathic surgery

Prognosis

From a cleft palate standpoint, with surgical repair, the prognosis is excellent. Feeding difficulties are resolved with the closure of the cleft. Long-term sequelae related to post-operative scarring are managed with surgical scar revisions and revision palatoplasty, which also have good outcomes.

Complications

Cleft lip taping and NAM placement are most commonly complicated by skin irritation and breakdown due to adhesives. Lip adhesion can be complicated by excessive scarring, which may yield a poorer cosmetic outcome and can add to the difficulty of definitive repair. Further, the procedure is performed at a much younger age (4-6 weeks old) and can fail in the form of wound dehiscence or development of a nasolabial fistula.

Palatoplasty can be complicated by wound dehiscence with or without fistula development. Inadequate recognition of a short palate or failure to adequately lengthen the palate and resuspend the levator veli palatini muscle sling can result in velopharyngeal insufficiency (VPI). In VPI, there is an inability to elevate the palate to close off the nasopharynx from the oropharynx during a swallow, resulting in nasal reflux, and during speech, resulting in hypernasal speech.