Sven Kreiborg
Nuno V. Hermann
Cleft lip and palate (CLP) may have severe consequences for affected individuals because oral clefts interfere with two of the most important means of communication: facial expression and speech. Individuals with either unoperated or operated clefts usually have a face which differs from that of unaffected individuals. Studies including both unoperated and operated individuals have shown that some deviations are directly caused by the primary anomaly, while others are caused by the surgical interventions and the subsequent dysplastic and compensatory growth of the facial bones (Dahl, 1970; Ehmann, 1989; Mars and Houston, 1990; Dahl and Kreiborg, 1995; Sandham and Foong, 1997).
Semb and Shaw (1996) suggested several factors that may be potential sources of interference with the normal craniofacial growth pattern in individuals with clefts:
1. Variations intrinsically associated with the cleft malformation
2. Other variations intrinsically associated with the cleft
3. Functional adaptations
4. Surgical iatrogenesis.
Severe surgical iatrogenesis to maxillary development in individuals with clefts has been documented repeatedly (Graber, 1949, 1954; Slaughter and Brodie, 1949; Bishara and Olin, 1972; Friede and Pruzansky, 1972a,b; Friede and Johanson, 1974; Tomanova and Müllerova, 1994). Attention has been drawn to the harmful interference with the maxillary growth zones (Friede, 1998), including the premaxillary-vomerine complex (Pruzansky, 1971; Friede and Morgan, 1976; Friede, 1977, 1978). As a consequence of these studies, certain surgical procedures, such as premaxillary setback and primary bone grafting, have been largely abandoned because they were shown to lead to disturbed maxillary growth and facial concavity. However, even more cautious surgical procedures are claimed to interfere with maxillary growth. Maxillary retrognathia is a good example. Some authors believe that in subjects with CLP, maxillary retrognathia is intrinsically associated with the primary cleft malformation. Others, however, claim it to be caused by surgical iatrogenesis (Bishara et al., 1976; Dahl et al., 1982, 1989; Semb and Shaw, 1996; Hermann et al., 1999a). The major reason for this disagreement is the scarcity of data based on large, consecutive, well-controlled samples on the craniofacial morphogenesis of infants with oral clefts before surgery. This lack of information is not surprising. In many institutions, cleft lip (CL) is surgically treated within the first couple of months after birth. Thus, the available period to examine the unoperated state is short.
Comprehensive quantitative analysis of the infant's craniofacial morphology requires the use of infant roentgencephalometry (Pruzansky and Lis, 1958), including several projections, combined with study models of the maxilla. Although infant cephalometry was introduced more than 50 years ago and has been shown to be useful in the study of congenital craniofacial anomalies (Pruzansky and Lis, 1958; Kreiborg, 1985), few investigators have adopted these techniques in the evaluation of patients with CLP (Mazaheri and Sahni, 1969; Pruzansky, 1971, 1973; Robertson and Hilton, 1971; Friede and Pruzansky, 1972a,b; Dahan, 1974; Krogman et al., 1975, 1982a,b; Ishiguru et al., 1976; Friede, 1977; Kreiborg et al., 1977, 1985; Dahl et al., 1982, 1989; Long et al., 1982; Jain and Krogman, 1983a,b; Friede et al., 1986; Berkowitz, 1995; Han et al., 1995; Molsted et al., 1995; Kreiborg and Cohen, 1996; Hermann et al., 1999a,b; 2000, 2001b). Furthermore, most of the relatively few cephalometric studies of unoperated infants with CLP have been limited to the lateral projection, a few have included the frontal projection, and only a handful have included the lateral, frontal, and axial projections (Dahan, 1974; Dahl et al., 1982; Molsted et al., 1995; Hermann et al., 1999a,b, 2000). All but one of the latter studies come from our group in Copenhagen, and these studies form the basis of this chapter.
Additional information about the primary anomaly can be obtained from studies of older children, adolescents, and adults with unoperated clefts. A number of such roentgencephalometric studies have been published on subjects from Brazil, Cameroon, Czekoslovakia, Denmark, India, Mexico, and Sri Lanka, among others (Ortiz-Monasterio et al., 1959, 1966; Bishara, 1973; Bishara et al., 1976, 1985, 1986; Dahl, 1970; Smahel et al., 1987; Ehmann, 1989; Mars and Houston, 1990; da Silva Filho et al., 1992a,b, 1998; Capelozza et al., 1993; Capelozza Filho et al., 1996). However, most of these studies are limited by small sample sizes and the mixture of unoperated, partially operated, and late operated individuals. Cephalometric findings are also limited since often they only include the lateral projection or perform simplistic cephalometric analyses, typically based on 15 to 20 reference points, or measure maxillary prognathism as the nasion-sella-point A angle or similar measurements to the premaxilla.
The aim of this chapter is to summarize the available information on the intrinsic craniofacial morphology in individuals with oral clefts. The data presented here come primarily from our own studies but are supplemented with findings from the literature, especially regarding unoperated older children, adolescents, and adults.
Material and Methods
Inspired by Dr. Samuel Pruzansky, we designed a three-projection cephalometer in the mid-1970s (Kreiborg et al., 1977) (Figs. 8.1,8.2). From 1976 to 1981, we examined nearly all infants born with a cleft in Denmark (Jensen et al., 1988). Almost all children were examined at both 2 months (prior to any surgery) and 22 months of age by three-projection cephalometry and impressions of the palate. More than 600 consecutive cases were examined. A comprehensive set of cephalometric landmarks (n = 279), defining all craniofacial regions, was built into a digitizing system (Kreiborg, 1981, 1989; Heller et al., 1995; Hermann et al., 2001a) (Color Figs. 8.3,8.4 and 8.5).
The total sample of nonsyndromic oral cleft individuals comprised more than 600. Patients were divided into four groups: CL (cleft of the primary palate only); CP (cleft of the secondary palate only); Robin sequence (RS) (CP, glossoptosis, and micrognathia); and CLP (cleft of both the primary and secondary palate). Cases with CLP were subsequently classified according to severity (Jensen et al., 1988) (Fig. 8.6).
By the time this chapter was submitted for publication, the following groups had been analyzed:
1. Unilateral incomplete CL (UICL) at 2 and 22 months of age (Hermann et al, 1999a,b, 2000, 2001b; Darvann et al., 2001)
2. Isolated CP at 2 and 22 months of age (Dahl et al., 1982, 1989; Kreiborg et al., 1985; Kreiborg and Cohen, 1996; Hermann et al., 2001b)
3. RS at 2 and 22 months of age (Kreiborg et al., 1985; Kreiborg and Cohen, 1996; Hermann et al., 2001b)
4. Unilateral complete CLP (UCCLP) at 2 and 22 months of age (Hermann et al., 1999a,b, 2000, 2001b; Darvann et al., 2001)
5. Bilateral complete CLP (BCCLP) at 2 months of age (Dahl et al., 1989)
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FIG. 8.1. Roentgencephalometric unit with two high-kilovoltage x-ray tubes for infants. (From Kreiborg et al., 1977, with permission.) |
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FIG. 8.2. The x-ray tube above the cephalostat is tilted 45 degrees for the axial projection. The center of rotation is located at the axial ray of the x-ray tube for the lateral projection. The correct orientation of the head is secured by the ear rods and a light cross projected on the face. Note that the casette holder for this projection has an angulation of 45 degrees to the vertical plane. (From Kreiborg et al., 1977, with permission.) |
Cleft Lip
Isolated CL involves only structures of the embryonic primary palate. The craniofacial morphology in subjects with CL is fairly normal, except for the small region of the cleft including the premaxilla and the incisors. In unoperated bilateral complete CL, the premaxilla may protrude markedly. In unilateral complete CL, the protrusion is less pronounced but asymmetric. In subjects with UICL, the protrusion of the premaxilla is negligible (Hermann et al., 1999a). The interorbital distance in subjects with CL appears to be slightly increased. The basal part of the maxilla has normal prognathism in relation to the anterior cranial base, and the mandible is of normal size, shape, and inclination (Dahl, 1970; Hermann et al., 1999a). Following lip surgery, the premaxilla is molded into a normal position by pressure from the soft tissue and maxillary prognathism measured to point A or ss (subspinale) is normal (Dahl, 1970; Han et al., 1995; Hermann et al., 1999a,b,2000) (Fig. 8.7). Consequently, for the purpose of this chapter, the group patients with UICL was used as a control.
Cleft Palate
Isolated CP involves only structures of the embryonic secondary palate. Dahl et al. (1982, 1989) reported on 30 unoperated 2-month-old cases with CP from our sample. In Figure 8.8, the mean facial diagram of the CP group is superimposed on the mean facial diagram of a group of age-matched infants with CL (control group). The major deviations in the CP group were bimaxillary retrognathia, reduced length and posterior height of the maxilla, and reduced length of the mandible with mandibular retrognathia. The sagittal jaw relationship was normal. In the CP group, the upper airway dimensions were reduced. Hermann et al. (2001b) found similar deviations in infants with CP. They also observed increased width of the maxilla and nasal cavity. The mean facial growth pattern in the CP group from 2 to 22 months of age, before palatal surgery, was reported by Kreiborg and Cohen (1996) (Fig. 8.9). The facial growth pattern seemed harmonious. The bimaxillary retrognathia, with a normal sagittal jaw relationship, persisted. The cranial base angle decreased somewhat. The direction of facial growth was, however, more vertical than in the control group.
Bimaxillary retrognathia has been documented in unoperated older children (Smahel et al., 1987) and adults (Dahl, 1970; Bishara, 1972) with CP and must be considered as a variation intrinsically associated with the cleft malfornation. Dahl (1970) found an increased vertical dimension of the face in adult CP subjects (Fig. 8.10).
Robin Sequence
Robin sequence is defined by the presence of the following three cardinal signs: isolated CP, micrognathia, and glossoptosis (Gorlin et al., 1990). It may be part of several syndromes, e.g., Treacher Collins syndrome (Kreiborg and Cohen, 1996; Cohen, 1997). In this chapter, only nonsyndromic cases of RS will be discussed. We consider this to be a subgroup of the larger CP group.
Kreiborg et al. (1985) and Kreiborg and Cohen (1996) have described the unoperated infant facial morphology and early facial growth in eight consecutive cases from our sample. In Figure 8.11, the mean facial diagram of the RS group at 2 months of age is superimposed on the mean facial diagram of an age-matched CP group (Kreiborg and Cohen, 1996). The RS infants had a significantly smaller cranial base angle (nasion-sella-basion), shorter mandible with more marked mandibular retrognathia, and smaller depth of the bony nasopharynx than the CP infants. The degree of maxillary retrognathia was similar in the RS and the CP groups compared to infants with UICL. The marked mandibular retrognathia in the RS group was confirmed by Hermann et al. (2001b), documenting significant mandibular retrognathia in the CP group and even more marked retrognathia in RS subjects. Both studies concluded that RS subjects probably represent the extreme part of the CP population in terms of mandibular retrognathia and upper airway constriction.
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FIG. 8.5. Landmarks and their names in the axial x-ray. All landmarks belong to one single layer. (From Hermann et al., 1999a, with permission.) |
The facial growth pattern in the RS group from 2 to 22 months of age, before palatal surgery, is illustrated in Figure 8.12 (Kreiborg and Cohen, 1996). Facial growth seemed harmonious. At 22 months of age, the maxilla was still retrognathic and the mandible was also still markedly retrognathic compared to the CP group (Fig. 8.13). However, all patients with RS had outgrown their airway problems because of the increase in facial and airway dimensions.
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FIG. 8.6. The principle of catagorizing cleft lip and palate (Jensen et al., 1988). The extent of the cleft lip and the cleft palate was divided into four grades. Cleft lip: grade 1, up to one-third of lip height; grade 2, greater than one-third to two-thirds of lip height; grade 3, greater than two-thirds to subtotal; grade 4, total. Cleft palate: grade 1, soft palate; grade 2, one-third of hard palate; grade 3, greater than one-third up to subtotal; grade 4, total. |
As mentioned above, the RS group is considered a special subgroup of the CP group. Accordingly, it is believed that the bimaxillary retrognathia is intrinsically associated with clefting of the secondary palate.
Cleft Lip and Palate
Combined clefts of the lip, alveolous, and palate involve structures of both the embryonic primary palate and secondary palate. In Figure 8.14, the mean craniofacial morphology in 2-month-old unoperated infants with UCCLP is compared to a control group consisting of individuals with UICL (Hermann et al., 1999a). No marked differences were observed in the calvaria or cranial base. A number of significant differences were found, however, in the facial structures. In UCCLP group, the most pronounced deviations were observed in the maxillary complex and the mandible. The most striking findings were the markedly increased width of the maxilla and nasal cavity, a short mandible, and bimaxillary retrognathia except for the premaxillary area, which was relatively protruding and asymmetric. Facial retrognathia was also suggested to be part of the primary anomalies associated with the cleft deformity in unilateral CLP by Sandham and Foong (1997). Increased width of the midface and nasal cavity has been reported in unoperated UCCLP infants (Han et al., 1995) and in unoperated adults with UCCLP (Motohashi et al., 1994). Relative protrusion and asymmetry of the premaxilla have also been reported in unoperated UCCLP children, adolescents, and adults (Ortiz-Monasterio et al., 1959, 1966; Bishara et al., 1976, 1985, 1986; Capelozza et al., 1993), probably due to overgrowth in the premaxillary-vomerine complex (Pruzansky, 1971; Friede and Morgan, 1976; Friede, 1978). The overgrowth is probably an effect of the lack of structural integrety in the region. The relative protrusion of the premaxilla explains why the measurements s-n-ans (sella-nasion-anterior nasal spine) and s-n-ss (S-N-A) in the infant UCCLP group are comparable to the values in the control group, despite the fact that the UCCLP group showed significant maxillary retrognathia measured to the lateral segments. Also, several studies of older unoperated UCCLP children and adults have found the maxillary prognathism to be within normal limits or even increased compared to normative data (Ortiz-Monasterio et al, 1959,1966; Mars and Houston, 1990; Capelozza et al., 1993). All of these studies, however, measured prognathism only to the A point or to the point ANS, both located in the relatively protruding premaxilla. Ortiz-Monasterio et al. (1959) concluded the following, based on their findings in unoperated adults with UCCLP: “The embryonic factor responsible for the facial cleft does not interfere with maxillary growth. This evidence leads us to believe that growth defects of the middle third of the face so frequently seen are caused by early or repeated and agressive surgery.” We disagree somewhat with this conclusion. Based on our studies of infants with UCCLP, the maxillary retrognathia in this group appears to be part of the intrinsic variations associated with the cleft malformation of the secondary palate. In the unoperated infant and the unoperated adult, the maxillary retrognathia is, however, partly masked by relative protrusion of the premaxilla, secondary to overgrowth in the premaxillary-vomerine suture. Surgical closure of the lip at 2 months of age molds the premaxilla back into place, unmasking the maxillary retrognathia (Figs. 8.15,8.16). Thus, we believe that the bimaxillary retrognathia shown in Figure 8.15 illustrates the facial type characteristic of the 22-month-old lip-operated UCCLP group. The maxillary retrognathia observed at 22 months of age, therefore, should not be considered the result of surgical iatrogenesis. Rather, it represents a normalization of the “intrinsic facial type” characteristic of subjects with UCCLP. By the time this chapter went to press, the sample had not yet been reexamined at older ages. Therefore, it is not possible to comment on facial growth and signs of further surgical iatrogenesis after the age of 2 years.
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FIG. 8.7. The average craniofacial growth from 2 to 22 months of age in the unilateral incomplete cleft lip (UICL) group (n = 45) in the lateral projection. (From Hermann et al., 1999b, with permission.) |
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FIG. 8.8. Mean drawings of the 2-month-old unoperated cleft palate (CP) and cleft lip (CL) groups (n = 30 in both groups) superimposed on the nasion-sella line and registered on the sella. (Modified from Dahl et al., 1989.) |
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FIG. 8.9. Average facial growth in the cleft palate (CP) group (n =30) from 2 to 22 months of age. Mean drawings are superimposed on the nasion-sella line and registered on the sella. (Modified from Kreiborg and Cohen, 1996.) |
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FIG. 8.10. Mean drawings of adult cleft palate (CP) and lip (CL) groups (n = 30 in both groups) superimposed on the nasion-sella line and registered on the sella. (Modified from Dahl et al., 1989.) |
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FIG. 8.11. Mean drawings of 2-month-old unoperated cleft palate (CP, n = 30) and Robin sequence (RS, n = 8) groups superimposed on the nasion-sella line and registered on the sella. (Modified from Kreiborg and Cohen, 1996.) |
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FIG. 8.12. Average growth in the Robin sequence (RS) group (n = 8) from 2 to 22 months of age. Mean drawings are superimposed on the nasion-sella line and registered on the sella. (Modified from Kreiborg and Cohen, 1996.) |
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FIG. 8.13. Mean drawings of 22-month-old unoperated cleft palate (CP, n = 30) and Robin sequence (RS, n, = 8) groups superimposed on the nasion-sella line and registered on the sella. (Modified from Kreiborg and Cohen, 1996.) |
Dahl et al. (1982) analyzed facial morphology in 2-month-old infants with unoperated BCCLP (n = 22) from our sample. Figure 8.17 illustrates the mean facial diagram of the BCCLP group superimposed on the mean facial diagram of an age-matched group with UICL (n = 30). The most obvious features in the BCCLP group were protrusion of the premaxilla, increased width of the maxilla and nasal cavity, reduced posterior maxillary height, and a short and retrognathic mandible. The body of the maxilla was, however, retrognathic when measured to both its anterior and posterior aspects. Thus, the protruding premaxilla was situated in a totally retrognathic face. The protruding premaxilla is probably the result of overgrowth in the premaxillary-vomerine complex secondary to lack of structural integrity in the region, as discussed above.
For comparison, Mars and Houston (1990) and da Silva Filho et al. (1998) described groups of adult unoperated patients with BCCLP and found extreme protrusion of the premaxilla and a very convex profile measured as the ANB angle. No measurements were performed to describe the position of the body of the maxilla.
The retrognathia of the body of the maxilla and the short and retrognathic mandible found in the present sample are, in our opinion, variations intrinsically associated with the cleft of the secondary palate (as discussed above). The facial growth pattern, from the time of lip surgery at 2 months of age to the time of palatal closure at 22 months of age, was characterized by a normal amount of jaw growth but an increased vertical growth direction (Hermann et al., 1999b) (Color Fig. 8.18).
Discussion and Conclusions
The findings discussed in this chapter support the suggestion of Dahl (1970) and others that facial clefts should be classified based on embryonic facial development, i.e., into clefts involving the primary palate only (CL), clefts involving the secondary palate only (CP), and clefts involving structures of both the primary and secondary palate (CLP). The postnatal facial morphology and growth in these groups differ greatly.
It has been the aim of this chapter to summarize the available information about the intrinsic variations in facial morphology associated with the different types of cleft malformation, to form a basis for valid estimations of the amount surgical iatrogenesis, especially to the maxillary development, introduced by different surgical procedures and regimes, including the timing of treatment.
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FIG. 8.14. Craniofacial mean drawings of 2-month-old unoperated unilateral complete cleft lip and palate (UCCLP, n = 82) and unilateral incomplete cleft lip (UICL, n = 75) groups superimposed on the nasion-sella line and registered on the sella. (From Hermann et al., 1999a, with permission.) |
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FIG. 8.15. Craniofacial mean drawings of 22-month-old lip-operated unilateral complete cleft lip and palate (UCCLP, n = 82) and unilateral incomplete cleft lip (UICL, n = 75) groups superimposed on the nasion-sella line and registered on the sella. (From Hermann et al., 2000, with permission.) |
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FIG. 8.16. Axial maxillary mean drawings of 22-month-old lip-operated unilateral complete cleft lip and palate (solid line) (n = 82) and unilateral incomplete cleft lip (dashed line) (n = 75) groups superimposed on the line between the left and right foramen ovale and registered on the midpoint of this line. (From Hermann et al., 2000, with permission.) |
Cleft Lip
Several studies indicate that clefts involving structures of the primary palate only are associated with minor variations in facial morphogenesis except for the area of the primary malformation. In general, unilateral and incomplete clefts show the mildest deviations (Dahl, 1970). Surgical closure of the CL, does not lead to disturbed maxillary growth (Dahl, 1970; Hermann et al., 2000). The development of the cranial base and mandible is unremarkable. However, a slight increase in interorbital distance has been reported (Dahl, 1970; Ishiguru et al., 1975; Dahl et al., 1982; Motohashi et al., 1994).
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FIG. 8.17. Mean drawings of 2-month-old unoperated bilateral cleft lip and palate (BCLP, n = 22) and cleft lip (CL, n = 30) groups superimposed on the nasion-sella line and registered on the sella. (Modified from Dahl et al., 1989.) |
Cleft Palate
Isolated CP appears to be associated with bimaxillary retrognathia, reduced length and posterior height of the maxilla, increased width of the maxilla and nasal cavity, reduced mandibular length, and reduced dimensions of the upper airway (Dahl, 1970; Dahl et al., 1982, 1989; Hermann et al., 2001b). The sagittal jaw relationship is normal and early facial growth in unoperated patients revealed no change in the facial pattern up to 22 months of age (Kreiborg and Cohen, 1996). This lack of change in facial pattern may be observed even into adulthood, except for a relative increase in anterior facial height, which can probably be explained by a more vertical growth pattern, most likely related to altered function, e.g., change in head posture (Sandham and Foong, 1997).
Robin Sequence
Subjects with RS represent the extreme part of the CP population in terms of mandibular retrognathia and upper airway constriction. In our study, patients with RS outgrew their breathing problems even without closure of the CP, simply through the growth in facial dimensions. However, at 22 months of age, the mandible was still significantly shorter and more retrognathic than in the CP group (Kreiborg and Cohen, 1996).
Cleft Lip and Palate
Complete clefts of the lip and palate (unilateral or bilateral) appear to be associated with the following intrinsic variations in the newborn:
1. Protrusion (or relative protrusion) of the premaxilla
2. Retrognathia of the body of the maxilla
3. Increased maxillary width
4. Increased width of the nasal cavity
5. Reduced posterior height of the maxilla
6. Short and retrognathic mandible
7. Reduced dimensions of the upper airway
Secondary to surgical closure of the lip at 2 months of age in UCCLP, we found that the premaxilla was molded into place, unmasking the intrinsic maxillary retrognathia and leading to a normal sagittal jaw relationship at 22 months of age. The amount of jaw growth was similar, except for the premaxillary molding, in both the UCCLP and the UICL (control) groups. The direction of growth, however, was more vertical in the UCCLP group.
Based on this concept, we found that surgery to the lip and anterior part of the hard palate at 2 months of age in UCCLP subjects appeared to influence the development of the maxillary complex, as observed at 22 months of age, in two beneficial ways: (1) the premaxilla was no longer relatively protruding and (2) it was less asymmetric. The nasal septum deviated less toward the noncleft side. The width of the nasal cavity and the posterior part of the maxilla had become relatively more normal, and the transverse position of the lateral maxillary segment on the noncleft side was closer to normal. The posterior height of the maxilla was still reduced to the same degree, the mandible was still short and retrognathic to the same degree, and bimaxillary retrognathia was still present. The only iatrogenic effect observed was that the lateral maxillary segment on the cleft side had become displaced toward the midsagittal plane anteriorly, resulting in a very narrow dental arch at the level of the deciduous canine (Hermann et al., 2000).
In conclusion, our findings suggest that subjects with cleft of the secondary palate have a special “intrinsic” facial type, primarily characterized by bimaxillary retrognathia and increased maxillary width. This facial type could be a “liability factor,” increasing the probability of CP or CLP (Hermann et al., 1999a,b). Finally, when evaluating the outcome of cleft surgery in subjects with CLP at adolescence or adulthood, com parisons should not be made to normal standards but rather to the adolescent and adult morphology seen in subjects with CP.
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