Predicting need for orthognathic surgery in early permanent dentition patients with unilateral cleft lip and palate using receiver operating characteristic analysis

Introduction

The purpose of this study was to predict the need for orthognathic surgery in patients with unilateral cleft lip and palate (UCLP) in the early permanent dentition.

Methods

In this retrospective cohort study, we included 61 patients with complete UCLP (36 male, 25 female; mean age, 18.47 years; range, 16.92-26.17 years). The subjects were grouped into an orthognathic surgery group and a nonsurgery group at the time of growth completion. Lateral cephalograms obtained at the age of 11 years were analyzed to compare the 2 groups. The receiver operating characteristic analysis was applied to predict the probability of the need for orthognathic surgery in early adulthood by using the measurements obtained at the age of 11 years.

Results

SNB, ANB, SN, overbite, overjet, maxillary length, mandibular body length, and L1-MP were found to be significantly different between the 2 groups. For a person with a score of 2 in the 3-variable-based criteria, the sensitivity and specificity for determining the need for surgical treatment were 90.0% and 83.9%, respectively (ANB, ≤−0.45°; overjet, ≤−2.00 mm; maxillary length, ≤47.25 mm).

Conclusions

Three cephalometric variables, the minimum number of discriminators required to obtain the optimum discriminant effectiveness, predicted the future need for orthognathic surgery with an accuracy of 86.9% in patients with UCLP.

Highlights

  • We evaluated growth patterns in unilateral cleft lip and palate patients.

  • We applied ROC analysis to predict later need for orthognathic surgery.

  • ANB, overjet, maxillary length at 11 years were associated with unfavorable prognoses.

  • Evaluation at 11 years simplifies decision making in early camouflage treatment.

Unilateral cleft lip and palate (UCLP) is a common craniofacial anomaly involving the failure of facial tissues to join properly during development. Therefore, patients with UCLP require multiple corrective surgical procedures from infancy to adulthood. Ross suggested that growth deficiency in those with cleft lip and palate can be attributed to 2 factors: the intrinsic factor is a developmental deficiency in the growth pattern in the midfacial skeleton, and the iatrogenic factor is the influence of the surgical repair of the lip and palate. A long-term negative effect of the scar tissue on the lip and palate has been related to the restriction of maxillary growth and an increase in the secondary deformities of jaws and dentition.

Less forward growth of the maxilla before the age of 8 years was observed after palatoplasty. A study reported a Class III tendency and a more hyperdivergent facial pattern in children with UCLP aged 12 years or less. A vertical growth deficiency of the maxilla was reported in them. Furthermore, Holst et al and Lisson et al demonstrated a significant clockwise rotation in the maxilla, a significantly reduced posterior midfacial height, and retruded maxillary and mandibular incisors in patients with cleft lip and palate at the beginning of late mixed dentition. Meazzini et al observed a significant decrease in the maxillary prominence in children with UCLP from the age of 5 years to the end of growth. Those with a similar initial ANB angle showed a late mandibular growth spurt, which played a crucial role in the final requirement for orthognathic surgery (OGS).

Ross suggested that OGS was necessary in 25% of patients with UCLP. Other studies have reported a need for orthognathic surgical correction in frequencies varying from 12.5% to 48%. Asians with UCLP were found to have a higher tendency of undergoing OGS. Heliovaara and Rautio suggested that a candidate for OGS in adulthood might have a sagittal maxillomandibular discrepancy at the age of 6 years. Children with UCLP with an ANB angle of less than −1° might require OGS combined with orthodontic treatment in the future. Nollet et al found that 85% of candidates for OGS were identified at the age of 9 years, with 11 subjects in the OGS group. No catch-up growth in the maxilla was observed between the ages of 6 and 10 years. Hence, children with UCLP with negative values of the ANB angle at 6 years showed no improvement after a 4-year period. Scheuer et al described an equation for patients with UCLP to predict the prognosis of SNA and SNB over a 4-year period from 8 to 12 years. The predictive values, calculated at 8 years, showed a more dramatic change in SNA and SNB from 12 to 16 years. However, in this study, the sample size was small, and the observation period was short. Furthermore, the effect of other skeletal and dental measurements in distinguishing a candidate for OGS should be considered by using a combination of sensitivity and specificity, and a simplified method.

Congenitally missing permanent teeth and malocclusion are common in children with UCLP. Studies have suggested a tendency toward skeletal Class III in those with cleft lip and palate. Hence, the timing of intervention and the type of orthodontic treatment performed affect their treatment outcome. Early permanent dentition is an appropriate time for orthodontists to perform a comprehensive orthodontic alignment and to evaluate for camouflage with the extraction of teeth as required. In patients with cleft lip and palate identified with an unfavorable prognosis and a high chance of future need for OGS to improve facial esthetics, extraction and camouflage orthodontic treatment should be deferred.

In this study, we differentiated facial growth patterns between those with UCLP requiring OGS and those not requiring surgery in the Craniofacial Research Center at Chang Gung Memorial Hospital, Taoyuan, Taiwan. The hypothesis was that the growth pattern at age 11 years was significantly different between subjects who needed OGS and those who received nonsurgical treatment. The ultimate goal was to develop a scoring system to predict a future need for OGS based on cephalometric variables at the age of 11 years for patients with UCLP.

Material and methods

In this retrospective cohort study, 145 persons with UCLP were found, and 84 were excluded: 24 had missing cephalometric data, 4 had unclear cephalograms at the age of 11 years, 3 had incomplete UCLP, 1 was diagnosed with Crouzon’s disease, 1 had hemifacial microsomia, 1 received OGS at the age of 16 years, 1 received a distraction osteogenesis, 2 had severe facial asymmetry, and 47 were under the age of 17 years. Finally, in this study, we investigated 61 Taiwanese patients (36 male, 25 female) with complete UCLP who were born between 1975 and 1998. All had been treated with the same protocol from infancy to adolescence and were under observation until the end of the growth period at the Craniofacial Research Center. The early lip and palate repair were performed by 4 plastic surgeons in our center. The patients had cheiloplasty at 3 to 6 months, 2-flap palatoplasty at 9 to 12 months, and alveolar bone grafting at 9 to 11 years. Optional orthodontic treatment was performed to align the maxillary anterior teeth before alveolar bone grafting. Those who had incomplete clefts, associated anomalies, severe facial asymmetry, a history of trauma, previous orthopedic treatment, or initial repairs at other institutions were excluded.

The subjects were divided into the OGS and the non-OGS (NOGS) groups according to the hospital records at a mean age of 18.5 years (range, 16.9-26.2 years). Those who had undergone OGS or were in the process of presurgical orthodontic preparation were classified as the OGS group. The orthodontist determined the need for OGS according to the facial profile, skeletal and dentoalveolar discrepancies, molar relationship, and dental compensation. We also considered the suggestions from the cephalometric treatment decision on borderline Class III malocclusion of Taiwanese people. Lateral cephalograms of each person were taken with rulers and analyzed at an age of approximately 11 years (T1) and at the completion of growth before OGS (T2). Radiographs were traced by 1 investigator (M.Y.C.K.) and verified by a senior orthodontist (E.W.C.K.). Cephalometric landmarks on the craniofacial complex were identified and digitized using 2-dimensional Dolphin software (version 11.5; Major Partner SAS, Villanova d’Asti, Italy). Once the images were captured into the software, calibration of the actual size of each image in millimeters was based on the measurement of the known distance (10 mm) of the ruler image shown on cephalograms. This calibration standardized all images. The 17 cephalometric measurements of skeletal and dental variables in both groups obtained at 2 time points are listed in Table I .

Table I
Definition of variables and errors in the study
Variables Definition Systemic error Random error
Sagittal relationship
SNA (°) Maxillary prominence 0.35 0.38
SNB (°) Mandibular prominence 0.85 0.28
ANB (°) Maxillomandibular relationship 0.37 0.28
SN (mm) Cranial base length 0.29 0.57
ANS-PMP (mm) Maxillary length 0.29 0.89
Go-Gn (mm) Mandibular body length 0.46 1.06
Vertical relationship
ANS-Gn, mm Lower anterior facial height 0.83 0.89
ANS-Gn/N-Gn (%) Ratio of lower facial height to total facial height 0.35 0.57
SNˆANS-PMP (°) Palatal plane inclination 0.39 0.45
SNˆGo-Gn (°) Mandibular plane angle 0.94 0.44
S-Go (mm) Posterior facial height 0.30 0.91
N-ANS (mm) Upper anterior facial height 0.30 0.87
N-Gn (mm) Total facial height 0.42 1.03
Dental relationship
Overbite (mm) Vertical projection of maxillary incisor over mandibular incisor 0.28 0.36
Overjet (mm) Horizontal projection of maxillary incisor to mandibular incisor 0.80 0.41
U1-SN (°) Maxillary incisor inclination to cranial base 0.12 0.57
L1-MP (°) Mandibular incisor inclination to mandibular plane 0.58 0.72

The paired t test with a 95% confidence interval showed no systematic measurement errors. Random error was analyzed with Dahlberg’s formula.

Statistical analysis

A chi-square test was performed for the OGS and NOGS groups. The subjects were matched for cleft side and sex, and paired t tests were performed. For the error study, 15 randomly selected lateral cephalometric films were traced and measured twice at a 2-month interval. Systemic errors were analyzed using a paired t test. Random errors of measurements ( Table I ) were calculated using Dahlberg’s formula, s(i) = √(∑d 2 /2n). The random errors of these measurements ranged from 0.36 to 1.06 mm and 0.28° to 0.72°. Two paired t tests with 95% confidence intervals showed no systematic measurement errors. Statistical analyses were performed with software (version 17.0: SPSS, Chicago, Ill). Descriptive statistics, including means, standard deviations, and Student t test results, were computed for each measurement.

Receiver operating characteristic (ROC) analysis was performed to determine the ability of cephalometric measurements to distinguish between the 2 groups at the age of 11 years. In the logistic regression, the dependent variable was the group (OGS vs NOGS) of subjects; the independent variable was the score that subjects received in the scoring system. The accuracy of each scoring system was calculated by comparing the estimated result with their real grouping.

This study was approved by the institutional review board and medical ethics committee of Chang Gung Memorial Hospital. The Helsinki Declaration guidelines were followed.

Results

We included 30 patients in the OGS group (20 male, 10 female; mean age at T1, 11.29 ± 0.81 years; mean age at T2, 18.80 ± 2.23 years) and 31 patients in the NOGS group (16 male, 15 female; mean age at T1, 11.27 ± 0.70 years; mean age at T2, 18.16 ± 1.06 years). Four subjects in the OGS group did not proceed with the OGS recommendation. However, for the purposes of this study, they were included in the OGS group. The distributions of sex and cleft side did not significantly differ between the 2 groups ( Table II ).

Table II
Descriptions of samples and time points for assessment
OGS group (n = 30) NOGS group (n = 31) P value
Sex
Male (n) 20 16 0.23
Female (n) 10 15
Distribution of cleft
Right (n) 6 10 0.28
Left (n) 24 21
Orthodontic treatment during teenage years
Yes (n) 3 19 (extraction )2 (nonextraction)
No (n) 27 10
Time point
T1 (y) 11.29 ± 0.81 11.27 ± 0.70
T2 (y) 18.80 ± 2.23 18.16 ± 1.06
Congenitally missing teeth
0 (n) 10 16
1 (n) 12 10
2 (n) 5 3
3 (n) 2 2
4 (n) 1 0
Supernumerary teeth (n) 6 3
Microdontia (n) 14 16
Timing for early lip and palate repair
Cheiloplasty, mean age 3.45 mo
(3-5 mo)
3.47 mo
(3-6 mo)
Palatoplasty, mean age 12.67 mo
(12 mo-1 y 4 mo)
12.18 mo
(10 mo-1 y 4 mo)
Pre-ABG orthodontic treatment (n) 10 11
ABG, mean age 9.40 y
(9 y-9 y 11 mo)
9.61 y
(8 y 11 m-11 y 8 mo)

19 subjects in the NOGS group received orthodontic treatment with extraction of bilateral mandibular first premolars during teenage years. The P values for sex and cleft side between the groups were evaluated using chi-square tests.

For the sagittal dimensions, the subjects in the OGS group exhibited a significantly more forward position of the mandible compared with those in the NOGS group at both the age of 11 years and the completion of growth ( P = 0.01; Table III ). The mean ANB angles were −2.77° in the OGS group and 1.62° in the NOGS group at the age of 11 years. A significant difference ( P <0.001) was observed between the 2 groups at all time points ( Fig 1 ).

Table III
Cephalometric variables of subjects at each time point
Variable OGS group (n = 30) NOGS group (n = 31) Mean difference P value 95% CI of the difference
Mean SD Mean SD Upper bound Lower bound
Sagittal
SNA (°)
T1 75.78 4.12 77.55 4.30 −1.77 0.11 −3.92 0.39
T2 75.62 4.15 76.24 4.01 −0.62 0.55 −2.71 1.47
SNB (°)
T1 78.53 4.10 75.93 3.49 2.60 0.01† 0.65 4.55
T2 79.96 4.99 76.87 3.91 3.08 0.01† 0.79 5.37
ANB (°)
T1 −2.77 2.88 1.62 2.01 −4.38 0.00‡ −5.65 −3.11
T2 −4.31 3.64 −0.63 2.46 −3.68 0.00‡ −5.27 −2.10
ANS-PMP (mm)
T1 45.12 2.76 47.47 2.52 −2.35 0.00‡ −3.71 −1.00
T2 47.14 3.57 49.77 2.92 −2.63 0.00‡ −4.30 −0.96
Go-Gn (mm)
T1 78.35 6.24 75.36 3.51 2.99 0.03* 0.37 5.61
T2 87.41 7.73 82.91 6.14 4.51 0.01† 0.94 8.08
SN (mm)
T1 63.68 3.28 65.76 3.96 −2.08 0.03* −3.95 −0.22
T2 67.52 3.66 69.20 5.10 −1.68 0.15 −3.96 0.60
Vertical
SNˆGo-Gn (°)
T1 39.05 5.23 38.69 4.39 0.36 0.77 −2.11 2.83
T2 38.19 6.37 36.73 5.65 1.46 0.35 −1.62 4.54
SNˆANS-PMP (°)
T1 12.59 5.21 12.10 4.01 0.49 0.68 −1.88 2.87
T2 9.83 3.23 8.90 3.84 0.93 0.31 −0.89 2.75
N-ANS (mm)
T1 49.86 3.93 50.10 3.30 −0.24 0.80 −2.10 1.62
T2 55.74 3.22 54.41 3.86 1.34 0.15 −0.49 3.16
ANS-Gn (mm)
T1 66.83 3.84 67.50 5.05 −0.67 0.56 −2.97 1.63
T2 76.69 5.55 75.80 5.69 0.89 0.54 −1.99 3.77
N-Gn (mm)
T1 116.53 6.18 117.14 6.15 −0.61 0.70 −3.77 2.56
T2 132.04 7.46 129.76 7.92 2.28 0.25 −1.66 6.23
ANS-Gn/N-Gn (%)
T1 57.37 2.04 57.59 2.44 −0.22 0.70 −1.38 0.93
T2 58.05 1.67 58.41 2.34 −0.36 0.49 −1.41 0.68
S-Go (mm)
T1 68.01 5.34 69.91 4.34 −1.90 0.13 −4.39 0.59
T2 79.87 7.34 81.35 6.38 −1.48 0.40 −5.00 2.04
Dental
Overbite (mm)
T1 4.71 2.78 3.09 2.14 1.61 0.01† 0.34 2.88
T2 2.58 3.91 1.03 1.46 1.56 0.05* 0.17 3.10
Overjet (mm)
T1 −4.99 2.33 −0.57 3.39 −4.42 0.00‡ −5.91 −2.93
T2 −6.16 3.45 0.95 2.74 −7.11 0.00‡ −8.70 −5.51
U1-SN (°)
T1 98.54 4.63 97.57 6.84 0.97 0.52 −2.02 3.96
T2 103.11 5.90 103.92 6.90 −0.81 0.62 −4.11 2.48
L1-MP (°)
T1 85.89 6.61 90.65 6.99 −4.76 0.01† −8.25 −1.28
T2 85.33 8.15 88.61 9.07 −3.27 0.14 −7.70 1.15
Only gold members can continue reading. Log In or Register to continue

Dec 12, 2018 | Posted by in Orthodontics | Comments Off on Predicting need for orthognathic surgery in early permanent dentition patients with unilateral cleft lip and palate using receiver operating characteristic analysis
Premium Wordpress Themes by UFO Themes