Cleft lip and palate and other craniofacial anomalies

16 May

Cleft lip and palate and other craniofacial anomalies
21.1. PREVALENCE
Cleft lip and palate is the most common craniofacial malformation, comprising 65 per cent of all anomalies affecting the head and neck. There are two distinct types of cleft anomaly, cleft lip with or without cleft palate and isolated cleft palate, which result from failure of fusion at two different stages of dentofacial development.
21.1.1. Cleft lip and palate
The prevalence of cleft lip and palate varies geographically and between different racial groups. Amongst Caucasians, this anomaly occurs in approximately 1 in every 750 live births. However, the prevalence is increasing. A family history can be found in around 40 per cent of cases of cleft lip with or without cleft palate, and the risk of unaffected parents having another child with this anomaly is 1 in 20. Males are affected more frequently than females, and the left side is involved more commonly than the right. Interestingly, the severity of the cleft is usually more marked when it arises in the less common variant.
21.1.2. Isolated cleft of the secondary palate
Isolated cleft occurs in around 1 in 2000 live births and affects females more often than males. Clefts of the secondary palate have a lesser genetic component, with a family history in around 20 per cent and a reduced risk of further affected offspring to normal parents (1 in 80).
Isolated cleft palate is also found as a feature in a number of syndromes including Down, Treacher–Collins, Pierre–Robin, and Klippel–Fiel syndromes.
21.2. AETIOLOGY
In normal development fusion of the embryological processes that comprise the upper lip occurs around the sixth week of intra-uterine life. ‘Flip-up’ of the palatal shelves from a vertical to a horizontal position followed by fusion to form the secondary palate occurs around the eighth week. Before fusion can take place the embryological processes must grow until they come into contact. Then breakdown of the overlying epithelium is followed by invasion of mesenchyme. If this process is to take place successfully, a number of different factors need to interact at the right time. An inherited tendency towards short palatal shelves, for example, can be compensated (to a degree) by overdevelopment of other factors. If one of these factors is also affected or an environmental insult occurs at the

P.219

time that palate formation is taking place, a cleft may result. Therefore cleft lip and palate is described as exhibiting polygenic inheritance with a threshold. Environmental factors (for example anticonvulsant drugs, folic acid deficiency, or steroid therapy) may thus precipitate a susceptible fetus towards the threshold.

It is postulated that isolated cleft palate is more common in females than males because transposition of the palatal shelves occurs later in the female fetus. Thus greater opportunity exists for an environmental insult to affect successful elevation, which is further hampered by widening of the face as a result of growth in the intervening period.
21.3. CLASSIFICATION
A number of classifications exist but, given the wide variation in clinical presentation, in practice it is often preferable to describe the presenting deformity in words (Fig. 21.1). However, in medicine in general, moves to standardize nomenclature have resulted in the introduction of national and international classifications which aim to embrace all medical conditions, thus facilitating epidemiology and management. Of these, the most widely accepted in the UK is the Read coding system. Table 21.1 gives the relevant Read and International Classification of Diseases (ICD) codes for cleft lip and palate anomaly.
21.4. PROBLEMS IN MANAGEMENT
21.4.1. Congenital anomalies
The disturbances in dental and skeletal development caused by the clefting process itself depend upon the site and severity of the cleft.
Lip only
There is little effect in this type, although notching of the alveolus adjacent to the cleft lip may sometimes be seen.
Lip and alveolus
A unilateral cleft of the lip and alveolus is not usually associated with segmental displacement. However, in bilateral cases the premaxilla may be rotated forwards. The lateral incisor on the side of the cleft may exhibit some of the following dental anomalies:
  • congenital absence
  • an abnormality of tooth size and/or shape

    P.220
  • enamel defects
  • two conical teeth, one on each side of the cleft.
Lip and palate
In unilateral clefts rotation and collapse of both segments inwards anteriorly is usually seen, although this is usually more marked on the side of the cleft (the lesser segment). In bilateral clefts both lateral segments are often collapsed behind a prominent premaxilla (Fig. 21.2).
Palate only
A widening of the arch posteriorly is usually seen.
It has been shown that individuals with a cleft have a more concave profile, and whilst a degree of this is due to a restriction of growth (see below), research indicates that cleft patients have a tendency towards a more retrognathic maxilla and mandible and also a reduced upper face height compared with the normal population.
21.4.2. Post-surgical distortions
Studies of individuals with unoperated clefts (usually in Third World countries) show that they do not experience a significant restriction of facial growth, although there is a lack of development in the region of the cleft itself, possibly because of tissue hypoplasia. In contrast, individuals who have undergone surgical repair of a cleft lip and palate exhibit marked restriction of mid-face growth anteroposteriorly and transversely (Fig. 21.3). This is attributed to the restraining effect of the scar tissue, which results from surgical intervention. It has been estimated that approximately 40 per cent of cleft patients suffer severe maxillary retrusion. Limitation of vertical growth of the maxilla coupled with a tendency for an increased lower facial height results in an excessive freeway space, and frequently overclosure (Fig. 21.4).
21.4.3. Hearing and speech
Speech development is adversely affected by the presence of fistulae in the palate (Fig. 21.5) and by velopharyngeal insufficiency (where the soft palate is not able to make an adequate contact with the back of the pharynx to close off the nasal airway).
A cleft involving the posterior part of the hard and soft palate will also involve the tensor palati muscles, which act on the Eustachian tube. This predisposes the patient to problems with middle-ear ventilation (known colloquially as ‘glue ear’). Obviously, hearing difficulties will also retard a child’s speech development. Therefore management of the child with a cleft involving the posterior palate must include audiological assessments and myringotomy with or without grommets as indicated.
21.4.4. Other congenital abnormalities
Around 20 per cent of babies with cleft anomalies, particularly with isolated cleft palate, have associated abnormalities, more frequently of the heart and extremities.
21.4.5. Dental anomalies
In addition to the affects on the teeth in the region of the cleft discussed above, the following anomalies are more prevalent in the remainder of the dentition:
  • delayed eruption (delay increases with severity of cleft)
  • hypodontia
  • general reduction in tooth size
  • abnormalities of tooth size and shape (Fig. 21.6)
  • enamel defects.
21.5. COORDINATION OF CARE
In order to minimize the number of hospital visits and to ensure integrated interdisciplinary management, it is essential to employ a team approach with joint clinics. The core members usually include the following:
  • orthodontist
  • maxillofacial surgeon
  • plastic surgeon
  • speech therapist
  • ear, nose, and throat (ENT) surgeon.
  • health visitor
21.6. MANAGEMENT
21.6.1. At birth
The birth of a child with a cleft anomaly will come as a shock and a disappointment for the parents. It is common for them to experience feelings of guilt and they will need time to grieve for the emotional loss of the ‘normal’ child that they anticipated. It is important to provide support for the mother at this time to ensure that bonding develops normally and that help with feeding is readily available for those infants with a cleft palate. Because a child with a cleft

P.222
will have difficulty in sucking, a bottle and teat which help direct the flow of milk into the mouth is helpful, for example a soft bottle which can be squeezed (Fig. 21.7). Details of a range of useful bottles and teats can be obtained from the support group CLAPA (the Cleft Lip and Palate Association) (Fig. 21.8). This group also provides support and counselling, which is usually greatly appreciated by the parents of a cleft baby. An explanation from a member of the cleft team of probable future management and the possiblities of modern treatment, together with a contact person for advice, is also recommended.
Some centres still advocate the use of acrylic plates designed to help with feeding or to move the displaced cleft segments actively towards a more normal relationship to aid subsequent surgical apposition. This approach, which is known as presurgical orthopaedics, is becoming less fashionable because of a lack of evidence of its efficacy and the good results produced by some cleft teams (for example Oslo) who do not employ presurgical plates.
21.6.2. Lip repair
There is a wide variation in the timing of primary lip repair, depending upon the preference and protocol of the surgeon and cleft team involved. Neonatal repair is still being evaluated. In the UK primary lip repair is, on average, carried out around 3 months of age. A number of different surgical techniques have been described (for example Millard, Delaire, and straight line). The best techniques aim to dissect out and re-oppose the muscles of the lip and alar base in their correct anatomical position. However, there is some controversy as to whether tissue movement should be achieved by subperiosteal dissection or supraperiosteal dissection and skin-lengthening cuts. The degree to which the alar cartlidge is dissected is also contentious, as is the use of a vomer flap.
Most centres repair bilateral cleft lips at the same procedure, but some still carry out two separate operations. Primary bone grafting of the alveolus at the time of lip repair has fallen into disrepute owing to the adverse effects upon subsequent growth.
21.6.3. Palate repair
In many European centres closure of the hard palate is delayed until 5 years of age or older in an effort to reduce the unwanted effects of early surgery upon growth. There is some evidence to suggest that transverse growth of the maxilla is improved. However, the adverse effect upon speech development has been well documented. In the UK hard and soft palate repair is undertaken, on average, between 9 and 12 months of age with the philosophy that any unwanted effects upon growth caused by repair at this stage (which can be compensated for to a degree by orthodontics and surgery) are preferable to fostering the development of poor articulatory habits, which can be extremely difficult to eradicate after the age of 5.
21.6.4. Primary dentition
The first formal speech assessment is usually carried out around 2 years of age, depending upon the needs of the child. Monitoring of a patient’s speech should continue throughout childhood, preferably at joint clinics, to pick up any developing problems that may arise with growth. An assessment with an ENT surgeon should also be arranged if this specialty has not been not involved at the time of primary repair.
It is important to minimize surgical interference with the cleft child’s life and ‘minor’ touch-ups should be avoided. Lip revision, prior to the start of schooling,

P.223

should be performed only if clearly indicated. Closure of any residual palatal fistulae may also be considered to help speech development. In a proportion of cases the repaired cleft palate does not completely seal off the nasopharynx during speech and nasal escape of air may occur, resulting in a nasal intonation to the child’s speech. If indicated by evidence from investigations such as speech assessment, videofluroscopy, and nasoendoscopy, a pharnyngoplasty may help. These operations, which involve moving mucosal or musculomucosal pharyngeal flaps to augment the shape and function of the soft palate, can reduce velopharngeal incompetence. If indicated, this should be carried out around 4 to 5 years of age.

Orthodontic treatment in the primary dentition is not warranted. However, during this stage it is important to develop good dental care habits, instituting fluoride supplements in non-fluoridated areas.
21.6.5. Mixed dentition
During this stage the restraining effect of surgery upon growth becomes more apparent, initially transversely in the upper arch and then anteroposteriorly as growth in the latter dimension predominates. With the eruption of the permanent incisors, defects in tooth number, formation, and position can be assessed. Often the upper incisors erupt into lingual occlusion and may also be displaced or rotated (Fig. 21.9).
In order to avoid straining patient cooperation, it is better if orthodontic intervention is concentrated into two phases. The first stage is usually carried out during the mixed dentition with the specific aim of preparing the patient for alveolar or secondary bone grafting, and it is preferable, if possible, to delay the correction of the upper incisors until then. The second stage is discussed in Section 21.6.6.
Alveolar (Secondary) bone grafting
This technique has significantly improved the orthodontic care of patients with an alveolar cleft as it involves repairing the defect with cancellous bone which confers the following advantages:
  • provision of bone through which the permanent canine (or lateral incisor) can erupt into the arch (Fig. 21.10);
  • the possibility of providing the patient with an intact arch;
  • improved alar base support;
  • aids closure of residual oronasal fistulae;
  • stabilization of a mobile premaxilla in a bilateral cleft.
For optimal results this procedure should be timed before the eruption of the permanent canines, at around 8–9 years, particularly as eruption of a tooth through the graft helps to stabilize it.
Before bone grafting is carried out, any transverse collapse of the segments should be corrected to allow complete exposure of the alveolar defect and to improve access for the surgeon. This is most commonly carried out by using the fixed expansion appliance called the quadhelix (see Section 13.4.4). This appliance has the advantage that additional arms or springs can be attached, if indicated, to procline the upper incisors, but in cases with more severe displacement and/or rotation of the incisors a simple fixed appliance can be used concurrently (Fig. 21.11). However, care is required to ensure that the roots of the teeth adjacent to the cleft are not moved out of their bony support, and it may be necessary to defer their complete alignment to the post-grafting stage. The expansion achieved should be retained, for example with a palatal arch, whilst bone grafting is carried

P.224
out (Fig. 21.12). Removing deciduous teeth and erupted supernumerary teeth in the region of the cleft prior to grafting substantially improves flap quality.
In patients with a bilateral complete cleft lip and palate it may be necessary to stabilize the mobile premaxillary segment after bone grafting in order to ensure that the graft takes. This can be accomplished by placement of a relatively rigid buccal archwire prior to bone grafting, which is left in situ for at least 3 months after the operation. If space closure on the side of the cleft is planned, consideration should be given to the need to extract the deciduous molars on that side prior to grafting in order to facilitate forward movement of the first permanent molar. However, any extractions should be carried out at least 3 weeks prior to bone grafting in order to allow healing of the keratinized mucosa.
Cancellous bone is currently used for bone grafting because it assumes the characteristics of the adjacent bone; however, this may change in the future as bone morphogenesis proteins become cheaper and more readily available. Cancellous bone can be harvested from a number of sites, but the iliac crest or the chin are currently most popular. Keratinized flaps should be raised and utilized for closure, as mucosal flaps may interfere with subsequent tooth eruption. Unerupted supernumerary teeth are commonly found in the cleft itself, and these can be removed at the time of operation. There is no substantive evidence to support the contention that simultaneous bone grafting of bilateral alveolar cleft jeopardizes the integrity of the premaxilla.
The complications of this technique include the following:
  • granuloma formation in the region of the graft — this often resolves with increased oral hygiene, but surgical removal may be required;
  • failure of the graft to take — this usually only occurs to a partial degree;
  • root resorption — relatively rare;
  • around 15 per cent of canines require exposure.

P.225
21.6.6. Permanent dentition
Once the permanent dentition has been established, but before further orthodontic treatment is planned, the patient should be assessed as to the need for orthognathic surgery to correct mid-face retrusion (see Chapter 20). The degree of maxillary retrognathia, the magnitude and effect of any future growth, and the patient’s wishes should all be taken into consideration. If surgical correction is indicated, this should be deferred until growth is complete (following any presurgical orthodontic alignment).
If orthodontics alone is indicated, this can be commenced once the permanent dentition is established. Usually fixed appliances are necessary (Fig. 21.13). If space closure in the region of the cleft is not feasible, treatment planning should be carried out in collaboration with a restorative opinion regarding the design of the prosthesis required.
At the end of orthodontic treatment, retention will be required. If the maxillary arch has been expanded, this will be particularly prone to relapse, and retention of the arch width with either a removable retainer worn at night or a partial denture (if indicated for prosthetic reasons) is advisable.
21.6.7. Completion of growth
A final surgical revision of the nose (rhinoplasty) may be carried out at this stage. However, if orthognathic surgery is planned, this should be carried out first, as movement of the underlying bone will affect the contour of the nose.
21.7. AUDIT OF CLEFT PALATE CARE
Audit of cleft palate management is difficult because of the different disciplines involved in providing care and the range of clinical presentations. In order to try to evaluate the effects of treatment, careful records taken before and after any intervention (surgical or orthodontic) must be a priority. These should include study models and photographs of the cleft prior to primary closure, so that the size and morphology of the original cleft can be taken into consideration. In addition, a cleft team should concentrate on a particular treatment protocol in order to gain the necessary expertise and experience to achieve successful results and to collate a meaningful amount of useful data. If the results of one surgical team carrying out a particular treatment protocol are to be compared with another treatment regimen carried out at a different centre, some standardization of these records is required. In the UK the Cranio-facial Society of Great Britain is attempting to standardize record collection with the Cranio-facial Anomalies REgister (CARE).
As in all branches of medicine, concentration of expertise and experience at a centre of excellence produces superior results to those obtained by a lone practitioner carrying out small numbers of a particular procedure each year. Therefore there is pressure to concentrate cleft palate care at regional centres. However, this approach has the disadvantage that the majority of patients will have to travel greater distances to receive their treatment. In other countries this problem is addressed by greater availability of central funding to transport patients and their families to receive treatment; accommodation costs are also included.

P.226
21.8. OTHER CRANIOFACIAL ANOMALIES
21.8.1. Hemifacial microsomia
This is the second most common craniofacial anomaly, with a prevalence of 1 in 5000 births. It is a congenital defect characterized by a lack of both hard and soft tissue on the affected side of the face, usually in the area of the mandibular ramus and external ear (i.e. in the region of the first and second branchial arches, hence its older name of first arch syndrome). This anomaly usually affects one side of the face (Fig. 21.14), but does present bilaterally in around 20 per cent of cases. A wide spectrum of ear and cranial nerve deformities are found. Goldenhar syndrome or oculo-auriculovertebral dysplasia (the latter name neatly explains the affected sites, but is more difficult to remember — and spell) is a variant of hemifacial microsomia.
Management usually involves a combination of surgery and orthodontic treatment. However, milder cases can sometimes be managed with orthodontic appliances alone. Orthodontic treatment usually involves the use of a specialized type of functional appliance known as a hybrid appliance, so called because components are selected according to the needs of the individual malocclusion, for example encouraging eruption of the buccal segment teeth on the affected side. The degree and type of surgery depends upon the severity of the defect, but three phases are recognized:
  • Early reconstruction (5 to 8 years of age), commonly with costochondral rib grafts, is usually reserved for severe cases with no functioning TMJ.
  • At the end of the adolescent growth spurt (around 12–15 years of age) — distraction osteogenesis (see section 20.4.4).
  • Late teens, to enhance the contour of the skeleton and soft tissues — conventional orthognathic and reconstructive techniques.
21.8.2. Treacher–Collins syndrome
This syndrome is also known as mandibulofacial dysostosis. It is inherited in an autosomal dominant manner and consists of the following features, which are present bilaterally:
  • downward sloping (anti-mongoloid slant) palpebral fissures and colobomas
    (notched iris with a displaced pupil);
  • hypoplastic malars;
  • mandibular retrognathia;
  • deformed ears, including middle and inner ear which can result in deafness;
  • hypoplastic air sinuses;
  • cleft palate in 30 per cent of cases;
  • most have completely normal intellectual function.
The specifics of management depend upon the features of the case, but usually staged craniofacial surgery is required. If a cleft palate is present, this is handled as described above.
21.8.3. Pierre Robin anomaly
This anomaly consists of retrognathia of the mandible, cleft palate, and glossoptosis, which together cause airway problems in the infant. Although originally thought to be due to raised intra-uterine pressure causing the head of the fetus to be compressed against the chest, thus restricting normal development of the

P.227

mandible, recent research would suggest a metabolic aetiological factor. The first priority at birth is to maintain the airway; in a proportion of cases it is necessary to use an endotracheal tube for the first few days, but once the child is older, or in less severe cases, prone nursing will suffice. Rarely, tracheostomy for medium-term airway protection is required. Subsequent management is as for cleft palate (see above). In a proportion of Pierre Robin children catch-up growth of the mandible does occur, but paediatric distraction osteogenesis (see section 20.4.4) or conventional orthognathic surgery can be planned for those with a markedly retrognathic mandible.

21.8.4. Craniosynostoses
In craniosynostosis and craniofacial synostoses, premature fusion of one or more of the sutures of the bones of the cranial base or vault occurs. The effects depend upon the site and extent of the premature fusion, but all have a marked effect upon growth. In some cases restriction of skull vault growth can lead to an increase in intracranial pressure which, if untreated, can lead to brain damage. If raised intracranial pressure is detected, release of the affected suture(s) before 6 months of age is indicated. This may be the only intervention needed in isolated craniosynostoses. Combined craniofacial synostoses (e.g. Crouzon syndrome, Apert syndrome) require subsequent staged orthodontic and surgical intervention. This may become the prime indication for telemetric distraction osteogenesis.
PRINCIPAL SOURCES AND FURTHER READING
Bergland, O., Semb, G., and Abyholm, F. E. (1986). Elimination of the residual alveolar cleft by secondary bone grafting and subsequent orthodontic treatment. Cleft Lip and Palate Journal, 23, 175–205.
This paper is now a classic. It describes the pioneering work by the Oslo cleft team on alveolar bone grafting.
Bhatia, S. N. (1972). Genetics of cleft lip and palate. British Dental Journal, 132, 95–103.
Gives an interesting hypothesis regarding the inheritance of cleft anomalies, but also includes insight on the genetics of other dental anomalies.
Clinical Standards Advisory Group (1998). Cleft lip and/or palate. Stationery Office, London.
Cousley, R. R. J. (1993). A comparison of two classification systems for hemifacial microsomia. British Journal of Oral and Maxillofacial Surgery, 31, 78–82.
Edwards, J. R. G. and Newall, D. R. (1985). The Pierre Robin syndrome reassessed in the light of recent research. British Journal of Plastic Surgery, 38, 339–42.
Ranta, R. (1986). A review of tooth formation in children in cleft lip/palate. American Journal of Orthodontics and Dentofacial Orthopedics, 90, 11–18.
Steinberg, M. D. et al. (1999). State of the art in oral and maxillofacial surgery: Treatment of maxillary hypoplasia and anterior palatal and alveolar clefts. Cleft Palate-Craniofacial Journal, 36, 283–291.
Thom, A. R. (1990). Modern managment of the cleft lip and palate patient. Dental Update, 17, 402–8.
An easy-to-read paper emphasizing the integration of preventive care in the overall management of the cleft palate patient.
Random Posts

Comments are closed.