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Management of Patients With Orofacial Clefts
A cleft is a congenital abnormal space or gap in the upper lip, alveolus, or palate. The colloquial term for this condition is harelip . The use of this term should be discouraged because it carries demeaning connotations. The more appropriate terms are cleft lip, cleft palate, or cleft lip and palate.
Clefts of the lip and palate are the most common serious congenital anomalies to affect the orofacial region. The initial appearance of clefts may be grotesque. Because clefts are deformities that can be seen, felt, and heard, they constitute a serious affliction to those who have them. Because of their location, clefts are deformities that involve the dental specialties throughout their protracted course of treatment. The general dentist will become involved in managing these patients’ special dental needs because these patients may have partial anodontia and supernumerary teeth. Malocclusion is usually present, and orthodontic therapy with or without corrective jaw surgery is frequently indicated.
The occurrence of a cleft deformity is a source of considerable shock to the parents of an afflicted baby, and the most appropriate approach to these parents is one of informed explanation and reassurance. Parents should be told that the defects are correctable and need not adversely affect the child's future. However, parents should be prepared for a protracted course of therapy to correct the cleft deformities and to allow the individual to function.
The problems encountered in the rehabilitation of patients with cleft deformities are unique. The treatment must address patient appearance, speech, hearing, mastication, and deglutition. Most children affected with orofacial clefts are managed by a team of professionals. Cleft teams are found in most cities of at least moderate size. These teams commonly are comprised of a general or pediatric dentist, an orthodontist, a prosthodontist, an oral-maxillofacial surgeon, a cosmetic surgeon, an audiologist, an otorhinolaryngologist, a pediatrician, a speech pathologist, a psychologist or psychiatrist, and a social worker. The number of specialists required reflects the number and complexity of the problems faced by individuals with orofacial clefts.
The occurrence of oral clefts in the United States has been estimated as 1 in 700 births. Clefts exhibit interesting racial predilections, occurring less frequently in blacks but more so in Asians. Boys are affected by orofacial clefts more often (at a ratio of 3 : 2) than girls. Cleft lip and palate (together) occur approximately twice as often in boys as in girls, whereas isolated clefts of the palate (without cleft lip) occur slightly more often in girls.
Oral clefts commonly affect the lip, alveolar ridge, and hard and soft palates. Three-fourths of clefts are unilateral deformities; one-fourth are bilateral. The left side is involved more often than the right when the defect is unilateral. The cleft may be incomplete; that is, it may not extend the entire distance from the lip to the soft palate. Cleft lip may occur without clefting of the palate, and isolated cleft palate may occur without clefting of the lip ( Fig. 28.1 ). A useful classification divides the anatomy into primary and secondary palates. The primary palate involves those structures anterior to the incisive foramen (the lip and the alveolus); the secondary palate consists of those structures posterior to the incisive foramen (the hard and soft palates). Thus an individual may have clefting of the primary palate, the secondary palate, or both ( Fig. 28.2 ).
Ventral view of palate, lip, and nose showing variability of cleft lip and palate deformity. (A) Normal. (B) Unilateral cleft lip extending into the nose. (C) Unilateral cleft involving the lip and alveolus, extending to the incisive foramen. (D) Bilateral cleft involving the lip and alveolus. (E) Isolated cleft palate. (F) Cleft palate combined with unilateral cleft of the alveolus and lip. (G) Bilateral complete cleft of lip and palate.
(Modified from Langman J. Medical Embryology . 3rd ed. Baltimore: Williams & Wilkins; 1975.)
Various types of cleft deformities. Nasal deformities are also apparent. (A) Unilateral complete cleft of lip and palate. (B) Bilateral cleft lip and palate, complete on right, incomplete on left. (C) Palatal view of isolated cleft palate. (D) Bifid uvula.
Clefts of the lip may range from a minute notch on the edge of the vermilion border to a wide cleft that extends into the nasal cavity and thus divides the nasal floor. Clefts of the soft palate may also show wide variations from a bifid uvula (see Fig. 28.2D ) to a wide inoperable cleft. The bifid uvula is the most minor form of cleft palate in which only the uvula is cleft. Submucosal clefts of the soft palate are occasionally seen. These clefts are also called occult clefts because they are not readily seen on cursory examination. The defect in such a cleft is a lack of continuity in the musculature of the soft palate. However, the oronasal mucosa is continuous and covers the muscular defect. To diagnose such a defect, the dentist inspects the soft palate while the patient says “ah.” This action lifts the soft palate, and in individuals with submucosal palatal clefts, a furrow in the midline is seen where the muscular discontinuity is present. The dentist can also palpate the posterior aspect of the hard palate to detect the absence of the posterior nasal spine, which is characteristically absent in submucosal clefts. If a patient shows hypernasal speech without an obvious soft palatal cleft, the dentist should suspect a submucosal cleft of the soft palate.
Embryology
To understand the causes of oral clefts, a review of nose, lip, and palate embryology is necessary. The entire process takes place between the fifth and tenth weeks of fetal life.
During the fifth week, two fast-growing ridges, the lateral and medial nasal swellings, surround the nasal vestige ( Fig. 28.3 ). The lateral swellings form the alae of the nose; the medial swellings give rise to four areas: (1) the middle portion of the nose, (2) the middle portion of the upper lip, (3) the middle portion of the maxilla, and (4) the entire primary palate. Simultaneously, the maxillary swellings approach the medial and lateral nasal swellings but remain separated from them by well-marked grooves.
During the next 2 weeks, the appearance of the face changes considerably. The maxillary swellings continue to grow in a medial direction and compress the medial nasal swellings toward the midline. Subsequently, these swellings simultaneously merge with each other and with the maxillary swellings laterally. Hence the upper lip is formed by the two medial nasal swellings and the two maxillary swellings.
The two medial swellings merge not only at the surface but also at the deeper level. The structures formed by the two merged swellings are known together as the intermaxillary segment ( Fig. 28.4 ), which is composed of three components: (1) a labial component, which forms the philtrum of the upper lip; (2) an upper jaw component, which carries the four incisor teeth; and (3) a palatal component, which forms the triangular primary palate. Above, the intermaxillary segment is continuous with the nasal septum, which is formed by the frontal prominence.
Two shelflike outgrowths from the maxillary swellings form the secondary palate. These palatine shelves appear in the sixth week of development and are directed obliquely downward on either side of the tongue. However, in the seventh week the palatine shelves ascend to attain a horizontal position above the tongue and fuse with each other, thereby forming the secondary palate. Anteriorly, the shelves fuse with the triangular primary palate, and the incisive foramen is formed at this junction. At the same time, the nasal septum grows down and joins the superior surface of the newly formed palate. The palatine shelves fuse with each other and with the primary palate between the seventh and tenth weeks of development.
Clefts of the primary palate result from a failure of the mesoderm to penetrate into the grooves between the medial nasal and maxillary processes, which prohibits their merging with one another. Clefts of the secondary palate are caused by a failure of the palatine shelves to fuse with one another. The causes for this are speculative and include failure of the tongue to descend into the oral cavity.
Causative Factors
The causes of facial clefting have been extensively investigated. The exact cause of clefting is unknown in most cases. For most cleft conditions, no single factor can be identified as the cause. However, it is important to distinguish between isolated clefts (in which the patient has no other related health problem) and clefts associated with other birth disorders or syndromes. A syndrome is a set of physical, developmental, and sometimes behavioral traits that occur together. Clefts have been identified as a feature in more than 300 syndromes, most of which are rare. Syndromes account for approximately 15% of the total number of cases of cleft lip and cleft palate but nearly 50% of cases of isolated cleft palate. Medical geneticists are usually asked to consult with the family of children born with syndromes to identify the specific syndrome and to provide information to the parents about the likelihood of another child being affected.
For nonsyndromic clefts, it was initially thought that heredity played a significant role in the causation. However, studies have been able to implicate genetics in only 20% to 30% of patients with cleft lip or palate. Even in those individuals whose genetic backgrounds may verify familial tendencies for facial clefting, the mode of inheritance is not completely understood. The cause is not a simple case of mendelian dominant or recessive inheritance but is multigenetic. The majority of nonsyndromic clefts appear to be caused by an interaction between the individual's genes (i.e., genetic predisposition) and certain factors in the environment that may or may not be specifically identified.
Environmental factors seem to play a contributory role at the critical time of embryologic development, when the lip and palatal halves are fusing. A host of environmental factors have been shown in experimental animals to result in clefting. Nutritional deficiencies, radiation, several drugs, hypoxia, viruses, and vitamin excesses or deficiencies can produce clefting in certain situations.
The risk for having another child with a cleft is based on a number of factors that are often unique in a particular family. These factors include the number of family members with clefts, how closely they are related, the race and sex of the affected individuals, and the type of cleft each person has. After a syndrome or complex disorder is excluded, recurrence risk counseling for a cleft can be offered to families. No genetic test can determine a person's individual chance of having a child with a cleft.
Every parent has approximately a 1 in 700 risk of having a child with a cleft. Once parents have a child with a cleft, the risk that the next child (and each succeeding child) will be affected is 2% to 5% (i.e., 2 to 5 chances in 100). If more than one person in the immediate family has a cleft, the risk rises to 10% to 12% (i.e., approximately 1 chance in 10). A parent who has a cleft has a 2% to 5% chance that his or her child will have a cleft. If the parent with a cleft also has a close relative with a cleft, the risk increases to 10% to 12% for their child being born with a cleft. The unaffected siblings of a child with a cleft have an increased risk of having a child with a cleft (1%, or 1 in 100, compared with 1 in 700 when no history of cleft exists). If a syndrome is involved, the risk for recurrence within a family can be as high as 50%. Genetic counselors may be consulted for parents of children with clefts or for persons with clefts who would like to obtain more information on the relative risks for their offspring.
Problems of Individuals With Clefts
Dental Problems
A cleft of the alveolus can often affect the development of the primary and permanent teeth and the jaw itself. The most common problems may be related to congenital absence of teeth and, ironically, supernumerary teeth ( Fig. 28.5 ). The cleft usually extends between the lateral incisor and the canine area. These teeth may be absent because of their proximity to the cleft; when present, they may be severely displaced so that eruption into the cleft margin is common. These teeth may also be morphologically deformed or hypomineralized. Supernumerary teeth occur frequently, especially around the cleft margins. These teeth usually must be removed at some point during the child's development. However, these teeth may be retained if they can furnish any useful function in the patient's overall dental rehabilitation. Frequently, supernumerary teeth of the permanent dentition are left until 2 to 3 months before alveolar cleft bone grafting because these teeth, although nonfunctional, maintain surrounding alveolar bone. If extracted earlier, this bone may resorb, making the alveolar cleft larger.
Malocclusion
Individuals affected with cleft deformities, especially those of the palate, show skeletal discrepancies between the size, shape, and position of their jaws. Class III malocclusion, seen in most cases, is caused by many factors. A common finding is mandibular prognathism, which is frequently relative and is caused more by the retrusion of the maxilla than by protrusion of the mandible (i.e., pseudoprognathism; Fig. 28.6 ). Missing or extra teeth may partially contribute to the malocclusion. However, retardation of maxillary growth is the factor most responsible for the malocclusion. In general, the operative trauma of the cleft closure and the resultant fibrosis (i.e., scar contracture) severely limit the amount of maxillary growth and development that can take place. The maxilla may be deficient in all three planes of space, with retrusion, constriction, and vertical underdevelopment common. Unilateral palatal clefts show collapse of the cleft side of the maxilla (i.e., the lesser segment) toward the center of the palate, which produces a narrow dental arch. Bilateral palatal clefts show collapse of all three segments or may have constriction of the posterior segments and protrusion of the anterior segment.
Orthodontic treatment may be necessary throughout the individual's childhood and adolescent years. Space maintenance and control is instituted during childhood. Appliances to maintain or increase the width of the dental arch are frequently used. This treatment is usually begun with the eruption of the first maxillary permanent molars.
Comprehensive orthodontic care is deferred until later, when most of the permanent teeth have erupted. Consideration for orthognathic surgical intervention for correction of skeletal discrepancies and occlusal disharmonies is frequently necessary at this time.
Nasal Deformity
Deformity of normal nasal architecture is commonly seen in individuals with cleft lips (see Fig. 28.2 ). If the cleft extends into the floor of the nose, the alar cartilage on that side is flared and the columella of the nose is pulled toward the side without the cleft. A lack of underlying bony support to the base of the nose compounds the problem.
Surgical correction of nasal deformities should usually be deferred until all clefts and associated problems have been corrected, because correction of the alveolar cleft defect and the maxillary skeletal retrusion alters the osseous foundation of the nose. Therefore improved changes in the nasal form result from these osseous procedures. Thus nasal revision may be the last corrective surgical procedure undergone by the individual affected by a cleft.
Feeding
Babies with cleft palates can swallow normally once the material being fed reaches the hypopharynx but have extreme difficulty producing the necessary negative pressure in their mouth to allow sucking breast milk or bottle milk. When a nipple is placed in the baby's mouth, he or she starts to suck just like any other newborn because the sucking and swallowing reflexes are normal. However, the musculature is undeveloped or not properly oriented to allow the sucking to be effective. This problem is easily overcome through the use of specially designed nipples that are elongated and extend further into the baby's mouth. The opening should be enlarged because the suck will not be as effective as in a normal baby. Other satisfactory methods are the use of eyedroppers or large syringes with rubber extension tubes connected to them. The tube is placed in the baby's mouth, and a small amount of solution is injected. These methods of feeding, although adequate for sustenance, require more time and care. Because the child will swallow a considerable amount of air when these feeding methods are used, the child is not usually fed in the recumbent position, and more frequent burping is necessary.
Ear Problems
Children with a cleft of the soft palate are predisposed to middle ear infections. The reason for this becomes clear on review of the anatomy of the soft palate musculature. The levator veli palatini and the tensor veli palatini, which are normally inserted into the same muscles on the opposite side, are left unattached when the soft palate is cleft. These muscles have their origins directly on or near the auditory tube. These muscles allow opening of the ostium of this tube into the nasopharynx. This action is demonstrated when middle ear pressures are equalized by swallowing during changes in atmospheric pressure, as when ascending or descending in an airplane.
When this function is disrupted, the middle ear is essentially a closed space, without a drainage mechanism. Serous fluid may then accumulate and result in serous otitis media. Should bacteria find their way from the nasopharynx into the middle ear, an infection can develop (i.e., suppurative otitis media). To make matters worse, the auditory tube in infants is at an angle that does not promote dependent drainage. With age, this angulation changes and allows more dependent drainage of the middle ear.
Children with cleft palate frequently need to have their middle ear “vented.” The otorhinolaryngologist, who creates a hole through the inferior aspect of the tympanic membrane and inserts a small plastic tube, performs this procedure, which drains the ear to the outside instead of the nasopharynx (myringotomy).
Chronic serous otitis media is common among children with cleft palate, and multiple myringotomies are frequently necessary. Chronic serous otitis media presents a serious threat to hearing.
Because of the chronic inflammation in the middle ear, hearing impairments are common in patients with cleft palate. The type of hearing loss experienced by the patient with cleft palate is conductive (i.e., the neural pathway to the brain continues to function normally). The defect in these instances is simply that sound cannot reach the auditory sensory organ as efficiently as it should because of the chronic inflammatory changes in the middle ear. However, if the problem is not corrected, permanent damage to the auditory sensory nerves (i.e., sensory neural loss) can also result. This type of damage is irreparable. The range of hearing impairment found in individuals with cleft palates is vast. The loss can be great enough so that normal-sounding speech is heard at less than one-half of expected volume. In addition, certain sounds of speech (called phonemes ), such as the “s,” “sh,” and “t” sounds, may be heard poorly. Audiograms are useful tools and are performed repeatedly on patients with cleft palates to monitor hearing ability and performance.
Speech Difficulties
Four speech problems are usually created by cleft lip and palate deformity. Retardation of consonant sounds (i.e., “p,” “b,” “t,” “d,” “k,” and “g”) is the most common finding. Because consonant sounds are necessary for the development of early vocabulary, much language activity is omitted. As a result, good sound discrimination is lacking by the time the palate is closed. Hypernasality is usual in the patient with a cleft of the soft palate and may remain after surgical correction. Dental malformation, malocclusion, and abnormal tongue placement may develop before the palate is closed and thus produce an articulation problem. Hearing problems contribute significantly to the many speech disorders common in patients with oral clefts.
In the normal individual, speech is created by the following scheme. Air is allowed to escape from the lungs, pass through the vocal cords, and enter the oral cavity. The position of the tongue, lips, lower jaw, and soft palate working together in a highly coordinated fashion results in the sounds of speech being produced. If the vocal cords are set into vibration while the airstream is passing between them, then voice is superimposed on the speech sounds that result from the relationships of the oral structures. The soft palate is raised during speech production, preventing air from escaping through the nose.
For clear speech, it is necessary for the individual to have complete control of the passage of air from the oropharynx to the nasopharynx. The hard palate provides the partition between the nasal and oral cavities. The soft palate functions as an important valve to control the distribution of escaping air between the oropharynx and nasopharynx ( Fig. 28.7 ). This is called the velopharyngeal mechanism (“velo” means soft palate). As the name implies, the two main components are (1) the soft palate and (2) the pharyngeal walls. When passive, the soft palate hangs downward toward the tongue, but during speech the muscles of the soft palate elevate it and draw it toward the posterior pharyngeal wall, which happens to the normal individual's soft palate when he or she is asked to say “ah.” In normal speech, this action takes place rapidly and with an unbelievable complexity so that the valving mechanism can allow large amounts of air to escape into the nasopharynx or can limit or eliminate the escape.
In individuals whose soft palate is cleft, the velopharyngeal mechanism cannot function because of the discontinuity of the musculature from one side to the other. Thus the soft palate cannot elevate to make contact with the pharyngeal wall. The result of this constant escape of air into the nasal cavity is hypernasal speech.
Individuals with cleft palate have compensatory velopharyngeal, tongue, and nasal mechanisms in an attempt to produce intelligible speech. The posterior and lateral pharyngeal walls obtain great mobility and attempt to narrow the passageway between the oropharynx and the nasopharynx during speech. A muscular bulge of the pharyngeal wall actually develops during attempts at closure of the passageway in some individuals with cleft palate and is known as Passavant ridge or bar . Individuals with cleft palates develop compensatory tongue postures and positions during speech to help valve the air coming from the larynx into the pharyngeal areas. Similarly, the superficial muscles around the nose involved in facial expression are recruited to help limit the amount of air escaping from the nasal cavity. In this instance, the valving is at the other end of the nasal cavity from the velopharyngeal mechanism. However, in an uncorrected cleft of the soft palate, it is literally impossible for compensatory mechanisms to produce a satisfactory velopharyngeal mechanism. Unfortunately, in surgically corrected soft palates, velopharyngeal competence is not always achieved with one operation, and secondary procedures are frequently necessary.
Speech pathologists are well versed in assisting children with cleft deformities to develop normal articulation skills. The earlier in life speech training is started in patients with cleft deformities, the better is the eventual outcome. The patient may need to undergo speech counseling for several years to produce acceptable speech.
When hearing problems are also present, the speech problems are compounded. Hearing loss at an early age is especially detrimental to the development of normal speech skills. The child who is unable to hear is unable to imitate normal speech. Thus the parents must be cognizant of their child's development and ensure that regular visits to the pediatrician are undertaken.
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