Skeletal Disproportion Research Articles

The effect of early intervention on skeletal pattern in Class II malocclusion: A randomized clinical trial

Early treatment for Class II malocclusion is frequently undertaken with the objective of correcting skeletal disproportion by altering the growth pattern. Because the majority of previous studies of growth modification for Class II malocclusion have been based on retrospective record reviews, the efficacy of such an approach has not been well established. In this controlled clinical trial, patients in the mixed dentition with overjet > or = 7 mm were randomly assigned to either early treatment with headgear, or modified bionator, or to observation. All patients were observed for 15 months with no other appliances used during this phase of the trial. The three groups, who were equivalent initially, experienced statistically significant differences (p < 0.01) in skeletal change. There was considerable variation in the pattern of change within all three groups, with about 80% of the treated children responding favorably. Although patients in both early treatment groups had approximately the same reduction in Class II severity, as reflected by change in the ANB angle, the mechanism of this change was different. The headgear group showed restricted forward movement of the maxilla, and the functional appliance group showed a greater increase in mandibular length. The permanence of these skeletal changes and their impact on the subsequent treatment remains to be evaluated.

Pubertal growth in response to testosterone replacement therapy for radiation-induced Leydig cell failure.

The adolescent growth pattern of eight boys, who had puberty induced with androgen replacement therapy following radiation-induced Leydig cell failure, was studied from induction of puberty at a mean age of 13.1 years (range 11.6-14.5) to final height at mean age of 18.8 years (range 17.7-20.3). The mean gains during puberty (SD) for standing height, sitting height, and sub-ischial leg length were 18.56 cm (3.98), 10.46 cm (2.39), and 8.1 cm (2.01) respectively, which were significantly reduced compared with normal Tanner standards (P < .001). The peak velocity for each parameter occurred in the 1st year of induced puberty in contrast to the pattern in normal adolescence, although the mean peak velocity for each auxological parameter was not significantly different from the normal Tanner standards. The mean adult standing height (SD), 167.5 cm (9.88), and mean adult leg length (SD), 80.8 cm (6.19), were not significantly different from the normal Tanner standards, whereas the mean adult sitting height (SD), 86.7 cm (4.78), was shorter (P < .001). Three of the eight patients had a leg length standard deviation score less sitting height standard deviation score in excess of +2.96 suggesting the presence of significant skeletal disproportion. Seven of the eight boys reached target genetic height, though in six, the final height was below mid-parental height (P < .05). The modest loss in height potential was mainly due to radiation-induced skeletal dysplasia attenuating the growth of the spine. The families of boys with radiation-induced Leydig cell failure requiring androgen replacement therapy can be reasonably optimistic about height prognosis as seven of the eight boys reached target genetic height.

Familial complex chromosomal rearrangement resulting in duplication/deletion of 6q1c to 6q16

A familial complex chromosomal rearrangement (CCR) was ascertained through a mentally retarded, dysmorphic individual. Carriers of the CCR have the karyotype 46,XX or XY, t(6;15)(q16;q21), ins(3;6)(q12;q14q16), and malsegregation of the CCR resulted in loss of the segment 6q14 to 6q16 in the proband, and in an additional copy of the same segment in three members of the extended family. The proband has features similar to other reported cases with deletion of 6q1. The individuals with duplication of 6q14 to 6q16 have moderate mental retardation, short stature, obesity, microcephaly, brachycephaly, a short smooth philtrum, central hair whorl, simian creases, 5th finger brachydactyly and skeletal disproportion. In the 4-generation family, CCR carriers have a 20% empiric risk of phenotypically abnormal livebirths.

Rating of facial attractiveness.

Epidemiologic investigations of orthodontic treatment should include both objective clinical measures and elements of perceptual assessment in the definition of malocclusion and skeletal disproportion. The effect of dental training and the view of the face presented as a stimulus on judgments of facial attractiveness were evaluated using a method recommended by Howells & Shaw (1) for epidemiologic surveys. Three views (two full face and one profile) of 18 orthodontic patients were presented as stimuli to three panels of judges with different levels of dental training (16 orthodontic residents, 17 dental students, and 71 undergraduate students). Ratings for facial attractiveness were obtained using a visual analog scale. The visual analog scores given the series of 54 slides by each judge were then ranked to create a "location-free" outcome measure. Both the ratings and the rankings of these ratings differed significantly among the three views for 80% of the patients. However, no view was consistently rated or ranked as most attractive across all patients. The ordering of the views from least to most attractive for a given patient appears to be highly dependent on the patient being presented as stimulus. Future studies should consider showing multiple views of a subject simultaneously if the intent is to obtain an overall treatment need score that incorporates assessment of facial attractiveness. The patients were consistently rated as more attractive by the orthodontic residents than by either dental or undergraduate students. When the ranks were analyzed, there were significant differences between the panels but the consistent pattern of differences between the panels disappeared.(ABSTRACT TRUNCATED AT 250 WORDS)

2 Irradiation-induced growth failure

GH deficiency, skeletal disproportion and early or precocious puberty may complicate irradiation to the head or axial skeleton in childhood. Certain cohorts of children are at particular risk, including those irradiated for brain tumours and various haematological malignancies. Both GH deficiency and impaired spinal growth may result in short stature, whereas the occurrence of early puberty in association with GH deficiency reduces the time available for GH therapy. The age of the child at irradiation is critical in that, in younger children, the central nervous system is more radiosensitive, the severity of the subsequent skeletal disproportion is greatest and the onset of puberty earliest. It is the very young craniospinally-irradiated child who is most at risk of extreme short stature.

Facial skeletal expansion: treatment strategies and rationale.

Forty-three nonconsecutive patients presenting with dentofacial deformity underwent surgical procedures designed intentionally to create skeletal disproportion in the sagittal and/or vertical dimensions. This was accomplished through expansion (enlargement) of the facial skeleton beyond normative standards. At the time of follow-up, which ranged from 14 to 36 months (mean 18.4 months), soft-tissue cephalometric analyses documented facial disproportion to exist in 37 of the 43 patients treated. Thirty-two patients had excessive anterior divergence (facial protrusion) at pogonion, and 17 patients had excessive lower face height as measured from subnasale to menton. All patients were judged to have had a favorable aesthetic outcome. This philosophy of facial skeletal expansion is predicated on two concepts: The first of these is that facial proportions and dimensions beyond those which are considered normal may be extremely attractive in a given individual. Second, the soft-tissue response to skeletal expansion is more favorable and predictable than it is to skeletal contraction in providing for well-supported soft tissues. This treatment planning approach is based on the dynamic interrelationship between the skeletal foundation and the soft-tissue facial mask. It relies on physical examination as the major determinant of aesthetic surgical options.

The evolution of spinal growth after irradiation

Spinal growth has been monitored in 13 children treated with craniospinal irradiation for brain tumours. Six were irradiated prepubertally and seven peripubertally, all with 30 Gy to the whole spine over four weeks. The change in (subis-chial leg length (SILL) — sitting height (SH)) standard deviation score (SDS) was used as an index of disproportionate segmental growth, which allowed the influence of growth hormone deficiency on growth to be discounted. Spinal growth over the prepubertal years was relatively normal: annual change in (SILL-SH) SDS was +0.07 SD 0.2. However, over puberty, annual change in (SILL-SH) SDS had increased significantly to +0.41 SD 0.14 ( P = 0.03). If irradiated peripubertally, annual change in (SILL-SH) SDS to final height was +0.22 SD 0.23, not significantly different from the change over puberty in the prepubertal group. Relatively normal spinal growth after irradiation in the prepubertal child should be interpreted with caution, as it is during puberty that skeletal disproportion manifests itself.

Maxillary Advancement for Mandibular Prognathism: Indications and Rationale

The surgical correction of mandibular prognathism has traditionally involved posterior repositioning of the mandibular body. This treatment approach corrects the skeletal disproportion at the expense of reducing facial skeletal volume and can unpredictably result in inadequately supported soft tissues with loss of skeletal definition. In an effort to avoid these sequelae of mandibular reduction, 18 patients diagnosed as having mandibular prognathism were treated with maxillary advancement surgery at the Le Fort I level. Mean patient SNB angle was 85.2 degrees, as compared with a normal 79 +/- 3 degrees. Maxillae were documented to be in normal position relative to both cranial base and Frankfort horizontal. The mean maxillary advancement was 6.9 mm, with a range of 4.5 to 8.8 mm. All patients required genioplasty to reduce vertical chin height and/or to laterally shift the chin. At the time of follow-up (mean 16.2 months), all patients retained cephalometric data suggestive of enlarged mandibles and excessive anterior facial divergence. However, maxillomandibular harmony and facial convexity had been restored without sacrificing skeletal volume. Treatment results demonstrated these faces to be skeletally well proportioned despite lower face protrusion that was beyond "normal." Postoperative appearances were characterized by a well-supported soft-tissue envelope and a highlighted skeletal foundation, creating angular, well-defined lower faces. These findings support the credibility of maxillary advancement as the procedure of choice in selected individuals with mandibular prognathism. Indications and an aesthetic rationale for this surgical approach are presented.

Effect of spinal irradiation on growth.

Standing height, sitting height, and leg length were measured in 79 patients (aged 16-30 years), who had been given craniospinal irradiation (n = 37) or cranial irradiation (n = 42) in childhood for a brain tumour and had completed their growth. Their measurements were compared with established standards for sitting height and leg length in British children (aged 16-18 years). To examine the effects of spinal irradiation on spinal growth independent of growth hormone deficiency we analysed the leg length (LL) minus sitting height (SH) standard deviation score (SDS) and used the cranial group as controls. There was an overall significant difference between the median craniospinal LL-SH SDS (1.98) and the median cranial LL-SH SDS (0.545). Within the craniospinal group there was a significant correlation with age at treatment, but there was no such correlation for the cranial group. After splitting age at treatment into three groups (0 less than 5, 5 less than 10, and 10-15 years) there was a significant difference between the LL-SH SDS of the craniospinal and cranial groups for each of the age ranges. In conclusion, spinal irradiation has a profound effect on spinal growth and the younger the child is when given irradiation the greater the subsequent skeletal disproportion. Our most conservative figures indicate that the eventual loss in height is 9 cm when irradiation is given at 1 year, 7 cm when given at 5 years, and 5.5 cm when given at 10 years.

EFFECT OF SPINAL IRRADIATION ON GROWTH

The standing height, sitting height and leg length have been measured in 79 patients (age 16-30 years), who received cranio-spinal (c/s) irradiation (n=37) or cranial irradiation (n=42) in childhood for a brain tumour and had completed their growth. Their measurements were compared to the established standards for sitting height and leg length in British children (age 16-18 years) (Tanner and Whitehouse, 1978). To examine the effects of spinal irradiation (DXT) on spinal growth independent of GH deficiency we analysed the leg length (LL) minus sitting height (SH) SDS and utilised the cranial group as controls. There was an overall statistically significant difference (p < 0.0001) between the median c/s LL-SH SDS (1.98) and the median cranial LL-SH SDS (0.545). Within the c/s group there was a significant correlation with age at treatment (Spearman's p=0.40 : p<0.02) but no such correlation for the cranial group. After splitting age at treatment into 3 groups (0 < 5, 5 < 10 and 10+ years) there was a significant difference between the LL-SH SDS of the c/s and cranial groups for each of the age groups.In conclusion spinal irradiation has a profound effect on spinal growth and the younger the irradiated child, the greater the subsequent skeletal disproportion. Our most conservative figures indicate that the eventual loss in height is 9cms if irradiated at one year, 7cms at five years and 5.5cms at ten years.

Skeletal abnormalities in homocystinuria

The skeletal changes of thirty-four patients with the biochemical and clinical features of cystathionine synthase deficiency are described. It is emphasized that there is clinical evidence of excessive bone growth and the formation for bone which is structurally weaker than normal. The similarities and differences between this condition and Marfan's syndrome are stressed and the possible nature of the connective tissue defect leading to the skeletal changes discussed. The most characteristic skeletal changes in homocystinuria are the skeletal disproportion (pubis-heel length greater than crown-pubis length), the abnormal vertebrae, sternal deformities, genu valgum and large metaphyses and epiphyses.

Constitutional statural overgrowth and increased lower body segment with normal sexual development in a family of four

I N THE newborn child measurement of trunk or upper body segment, taken from top of pubis to top of the)~ead, will be found to be greater than measurement of lower body segment, taken from pubis to heel, by as much as 5 inches. As time goes on, and as normal infant grows older, lower measurement gradually approaches upper measurement, unti l at about age of 10~ to 11 years, if he is still normal in development, lower measurement is almost equal to upper measurement. Finally, as child approaches age of 14 to 15 years~ and then thereafter into adulthood, lower measurement in male exceeds upper measurement by about one inch, and, in female, upper measurement exceeds the'lower by about one inch2 ~ Where there is abnormal genital development, such as with hypoplasia or cryptorchidism, there will be a derangement of these body measurements, especially, if abnormalities had their inception in early infancy. The extent of skeletal disproportion depends upon type and severity of endocrine disturbance, age of patient when distm'bance had its onset, and length of time it has been in existence. I have found that an increased lower body segment may be found in boys with gonadal insufficiency regardless of whether these boys present normal, accelerated, or depressed total linear height, whether patients present an adipose or nonadipose type of genital dystrophy, and whether origin of gonadal insufficiency is pituitary, pr imary gonadal, or thyroid. In cretin, where growth in general is interfered with severely and where linear growth specifically and most other developmentM processes are practically at a standstill, one may not find an increased lower body segment. TM b, Where gonadal insufficiency has existed since infancy in any of types of cases enumerated above, I have noted, after treating and studying many such endoeri~e cases over many years, that lower measurements are equal to upper measurements at about age of 6 or 7 years instead of at age of 10 89 or 11 years as in normal; and that, thereafter, lower measurements eventually surpass the upper measurements, not by an inch or so as in normal male, but by ~inches or even by as much as 7 inches or more. That is, skeletal disproportion is similar to that seen in eunuchism or eunuchoidism which has existed since early infancy--so-called eunuchoid skeletal proportions. Generally, eunuchoid proportions found in a patient indicate that a gonadal deficiency exists or had existed. In other words one usually assumes that two conditions accompany each other.