Assessment Of Skeletal Maturation And Its Correlation To Chronological Age Using The Cervical Vertebral Maturation Method In A Tertiary Care Hospital

Omair Majeed¹                                                              BDS

Tabassum Ahsan Quadeer²                                     BDS, FCPS

INTRODUCTION

In clinical orthodontics and dentofacial orthopedics it is becoming significant that the timing of treatment may be as crucial as the selection of relevant treatment protocol, because in the organization and development of a structure, time plays a viable role in determining the final morphological and dimensional result1,2.
Knowledge of the physiologic growth changes of the dentofacial complex is fundamental to orthodontic treatment planning3,4.
Because of individual variation in the timing of the pubertal growth spurt, chronological age is not a reliable tool for assessment of the development status. Other parameters, such as growth velocity, secondary sex changes, dental development and skeletal maturation have proven to be more accurate. The standard method to evaluate skeletal maturity has been the use of handwrist radiographs as skeletal maturation is generally determined by evaluating either the stage of ossification of bones of the hand and wrist, due to the large number of different types of bones available in this area5.
A method to assess skeletal maturation and a possible relationship to facial growth has used the morphology
of the cervical vertebrae6. Though the standard method of evaluating skeletal maturity has been a handwrist xray but in order to avoid taking an additional x-ray, some researchers sought to relate maturation with dental and
skeletal features other than the bones in the hand and wrist7. Interest in the maturational changes in both size
and shape of the cervical vertebrae dates back to the start of the century8.
Cervical vertebral maturation is an important diagnostic tool for evaluation of the pubertal growth spurt. It requires no additional x ray as the cervical vertebrae can be seen on a lateral cephalograph that is routinely done for orthodontics diagnosis and treatment planning9. Assessment of shape and size of the vertebrae gives the researcher an almost accurate idea as to the amount of growth remaining in a subject.
It has been proved by many researchers that cervical vertebral maturation has a high level of correlation with individual skeletal maturation10 and that the evaluation of the skeletal age was more efficient than that of the biological evaluation, by analyzing lateral cephalometric radiographs11.
The chronological age is not reliable in helping to establish the child’s stage of skeletal development12. It shows variability and therefore cannot accurately predict the amount of residual growth.
Ethnic and sex variations in the timing of skeletal maturation have also been noted13 according to which females are ahead of males at all levels of skeletal maturity, indicating early age of maturational development for females12.
To date, few international and very few local studies have compared chronological age and cervical vertebral maturation. The present study was conducted to determine the co-relation between the developmental age and the
chronological age. We hypothesized was that there is a strong co-relation between the developmental age and the chronological age.

METHODOLOGY

We used convenience sampling to gather the records of 53 subjects. This cross sectional study was done in the Department of Orthodontics at Bahria University Medical and Dental College, Karachi. Inclusion criteria’s for this study were male and female patients of Pakistani ethnicity, between 8-18 years of age, whose Cephalometric radiographs were available with high clarity and contrast. Records of the patients with congenital malformations of cervical vertebrae, and with a history of trauma to the vertebrae, were excluded from our study.
Records of the patients attending the orthodontic OPD for fixed/ removable orthodontic treatment at the Bahria University Medical and Dental College, and who fit our inclusion/exclusion criteria were selected. The chronological age was noted and confirmed by birth certificate; informed consent was taken from the patients that their records were being used for a study to cover the ethical issue. Our study was done on lateral cephalometric radiographs that are routinely taken for every orthodontic patient as an aid to treatment planning.
The odontoid process and the body of the second cervical vertebrae and the bodies of the third and fourth cervical
vertebrae were traced on acetate paper using 4H pencils on an illuminator. The anatomical changes observed in the concavity of the lower border and shapes of the vertebral body were studied in the following way:

Concavity of the lower border:

This is present when there is a distance of more than 1 mm between the middle of the lower border of the vertebral body and a line traced from the postero-inferior angle to the anteroinferior angle of the vertebral body. According to the concavity, six stages are defined:

Stage 1) All vertebrae have a flat lower border.
Stage 2) Concavity is present in the C2 lower border.
Stage 3) Concavity is present in the C3 lower border.
Stage 4) Concavity in C2 and C3 increases and a concavity is present in C4.
Stage 5) Concavity in all vertebrae.
Stage 6) Deep concavities in all vertebrae and the inferior angles are rounded.

Shape of the vertebral body:

This will be calculated at C3 and C4 and the following stages will be defined:
Stage 1) Upper border is tapered from the posterior to the anterior and wedge-shaped.
Stage 2) Wedge shaped C3 and nearly rectangular shaped C4 with absence of supero-anterior angles.
Stage 3) Rectangular shaped bodies.
Stage 4) Nearly squared bodies.
Stage 5) Squared bodies.
Stage 6) Rectangular shaped bodies with height greater than width.
Each stage was correlated with chronological age. Maturation was considered complete or positive when C5 (maturation) stage was achieved i.e. concavities seen in all vertebrae and the vertebrae C3 and C4 are square in shape.

STATISTICAL ANALYSIS

The collected data was analyzed by using SPSS version 22. Ratio (M: F) was computed to present gender distribution. Mean and standard deviation were computed to present age distribution. Frequency and percentages were used to present various stages of cervical vertebral maturation as stated in the operational definition. Spearman’s correlation coefficient was computed to determine correlation between chronological age and cervical vertebral maturation stages. Test of linear correlation was applied to compute p-value of significance at p< 0.05 level of significance. Age wise and gender wise stratification was done to control the confounding effect of these variables on correlation of two measurements.

RESULTS

In a total of 53 subjects, 22 were males and 31 were females (Table I) with the age range between 8 yearsand 18 years and a mean age range of 13.62 years (Table II).

Table I: GENDER DISTRIBUTION

Table II: AGE DISTRIBUTION

Table III: STAGES OF CERVICAL VERTEBRAL MATURATION

The most frequent cervical vertebrae stages in males were stage 4 followed equally by stage 1 and stage 3 (Table III). In females, the most frequent stages were stage 4 followed by stage 5. In age strata of 10-12 years, majority of male and female patients fell into stage 3 while in age strata of 12-14 years, majority of male and female patients fell into stage 4 (Table IV). Spearman rank order correlation coefficient between chronological age and cervical vertebral maturation stages was 0.90 for the sexes combined. Statistically insignificant correlations (p>0.05) were found between male and female subjects; at 0.93 and 0.85, respectively.

DISCUSSION

There is a plethora of studies on cervical vertebral maturation, chronological age and residual growth in an individual and almost all of the published literature goes to show the associations between these entities. There is very little local published literature as regards to the association between chronological age and cervical vertebral maturation and this was the reason for choosing such a study so as to generalize this method to orthodontic practice in Pakistani population. The limitation of our study is that it had a very small sample size and so our results will have less reliability. However further studies can add on this to establish more reliable results. The change in shape and size of the cervical vertebrae in growing individuals has gained much popularity in the last decade or so as a biological indicator of skeletal maturity. Skeletal maturity is the most commonly used index in routine clinical work and is closely related to sexual and somatic maturity2. It is important to identify a subject’s maturational levels, as in doing so the clinician can easily make a decision as to the type of treatment that need to be given in a very suitable manner.
The cervical vertebral method devised by Lamparski and later modified by Hassel and Farman includes changes
in the lower border and shape of the cervical vertebrae. The method of Hassel and Farman is better than the method by Lamparski because it requires the assessment of three vertebrae only i.e. C2, C3 and C4. The use of the cervical vertebrae does not require an additional radiograph of the hand and wrist as just one lateral cephalometric radiograph of the head provides a practical means to estimate adolescent growth14. It is divided into six stages and denotes growth in a descending fashion from CVMS1 to CVMS 6. The amount of residual growth in different stages is different. It is 80-100% in INITIATION, 65-85% in ACCELERATION, 25-65% in TRANSITION, 10-25% in DECELERATION, 5-10% in MATURATION and little or no growth in COMPLETION15.
This knowledge of residual growth has a lot of clinical significance in the field of Orthodontics. The method can be used as a maturational index to detect the optimal time to start treatment of jaw (maxilla or mandible) deficiencies by means of functional jaw orthopedics. The peak of mandibular growth starts at CVMS2 and reaches a peak at CVMS3 and this is the time when mandibular deficiencies can be best treated by functional appliances.
In the correction of vertical problems of the face caused by deficiency of the mandibular ramus, height can be controlled with orthopedic treatment at the peak in mandibular growth (CVMS3)16. In a study by Gu and Mc Namara Jr,17 the peak increase in mandibular length was observed during the interval between CVMS3 and CVMS 4.
Similarly treatment of skeletal class III malocclusions occurs effectively before the onset of CVMS 1. The use of CVM method also showed that rapid maxillary expansion before the peak in skeletal growth velocity is able to induce more pronounced transverse craniofacial changes at the skeletal level. During or after the peak, changes produced by expansion are largely dentoalveolar in nature1.
In our study, we divided 53 subjects (31 males and 22 females) into five age groups. In this way we were able to find the coincidence of the CVM stages in different age groups (Table IV and V).

In both males and females, the most frequent CVM stage was CVMS4 and it mostly occupied the age range between 12-14 years, while the stage that marks the peak of growth i.e. CVMS 3 was found to lie in the age range of 10-12 years (Table IV).
In males only, the peak stages i.e. from CVMS 2 to CVMS 3 lied in the age range between 10 -12 years (Table V) which goes to show that that any mandibular deficiency showed be treated at this stage. Similarly Uysal et al18 in their study using Hassel and Farman’s method in a sample of 503 subjects also showed the peak of males to lie in the age group between 9-12 years.
However, CVMS1 (INITIATION) in males was found to lie in the age range between 8-12 years which shows that treatment of maxillary deficiency showed be done well before this age. In females only, the peak stage CVMS 3 was found to lie in the 10-12 years age group (Table V). Uysal et al18 also found the peak stage to lie in the same age group.
In our study, the Spearman rank order correlation coefficient between chronological age and cervical vertebrae maturation stages was 0.90 for the sexes combined. Statistically in-significant correlations were found for the male and female subjects: 0.93 and 0.85 respectively (Table V). Uysal et al18 also found the Spearman’s coefficient between both parameters to be 0.72 for the sexes combined and 0.68 and 0.82 for males and females respectively. Sukhia and Fida19 in their study

found the Spearman’s coefficient between CVM stages and chronological age to be 0.78 for both the sexes. In the study of Hassel and Farman22, the correlation coefficient was 0.77 for boys and 0.84 for girls. In the study of Roman et al, 20 the age range was 5-13 years and the correlation coefficients were 0.79 for boys and 0.85 for girls. Therefore our study clearly indicates a high correlation between CVM stages and chronological age.

CONCLUSION

We conclude that there was a statistically significant correlation between chronological age and cervical vertebral maturation stages and that the peak of growth lies in the age range between 10-12 years.

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    1. Department of Orthodontics Bahria University Medical and Dental College.
    2. Assistant Prof. and Head Department of Orthodontics Bahria University Medical and Dental College
    Corresponding author: “Dr Omair Majeed ” < dromairis@hotmail.com >