Evaluation of the relationship between unilateral condylar hyperplasia and idiopathic scoliosis

Aim: The aim of this study is to understand the relationship between the altered maxillomandibular component and vertebral angle changes in patients with active condylar growth and to investigate the potential links between unilateral condylar hyperplasia and adolescent idiopathic scoliosis. In this context, it is purposed to evaluate the effects of mandibular condyle growth on the spinal structure by examining the relationship between maxillomandibular growth rates and vertebral curvature direction in patients diagnosed with unilateral mandibular condylar hyperplasia. At the same time, it is objected to examine the relationship between clinical subtypes (hemimandibular hyperplasia, hemimandibular elongation), ramus length difference, active growth rate of the condyle and Cobb angle to provide data of the effect of condylar hyperplasia on scoliosis. Materials and Methods: In our study, patients diagnosed with unilateral mandibular condylar hyperplasia, with a difference in right and left condylar growth rates greater than 1.10 as assessed by SPECT/CT, were retrospectively included from the patient database of the Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Baskent University. The control group included systemically healthy individuals with no history of orthodontic treatment or skeletal deformities, who underwent routine dental procedures under general anesthesia for various indications and had accessible chest radiographs. Cobb angle was measured on chest radiographs obtained from all individuals included in this study. The relationship between Cobb angle, vertebral curvature direction and location with clinical and radiological data such as growth ratio, ramus length difference measured by SPECT/CT and affected condyle side obtained from the patients included in the study group was statistically evaluated. Results: A total of 65 patients were included in the study; 30 patients diagnosed with unilateral condylar hyperplasia with active condylar growth and 35 patients in the control group. The mean age of the patients in the study group was 22.70±6.82 (min=16, max=44) and the gender distribution was 76.67% female (23 female, 7 male). The mean growth rate of the patients in the study group according to SPECT/CT was 1.51±0.61 (min=1.12, max=3.7) and the mean ramus length difference was 8.32±4.57 mm (min=0.44 mm, max=18.66 mm). In the study group the right condyle was affected in 14 patients and the left condyle was affected in 16 patients. The mean Cobb angle of the patients in the study group was measured as 6.92±5.44 degrees. In half of these patients (n=12), the vertebral curvature was directed to the right side and in 70.83%, the thoracic region was the most affected region. The mean age of the patients in the control group was 25.34±5.97 (min=16, max=38), and 18 females (51.43%) and 17 males were included. The mean Cobb angle of the patients in the control group was determined as 2.97±4.89 degrees. In the control group, the vertebral curvature direction was right in 8 patients and left in 7 patients, and the thoracic region was affected in 73.33% of these patients. The Cobb angle of the patients in the study group was found to be significantly higher than the Cobb angles of the patients in the control group (p<0.001). In evaluation of relationship between mandibular deviation and the direction of the vertebral curvature in study group patients we found that mandibular deviation was in the same side of the vertebral curvature however, this result was not statistically significant (p=0.219). Conclusion: According to the findings obtained in this study, the mean Cobb angle of patients diagnosed with unilateral condylar hyperplasia with active condylar growth was found to be significantly higher compared to the control group. However, no significant correlation was found between the affected condyle side and the direction of the vertebral curvature, ramus length difference, clinical subtypes and growth rate and the Cobb angle. These findings indicate that unilateral condylar hyperplasia may have variable effects on adolescent idiopathic scoliosis depending on the different physiological adaptation processes between individuals. The study provides the way for new studies to examine the relationship between condylar hyperplasia and scoliosis in larger patient groups, to observe the relationship with growth rate and to address clinical subtypes in more detail.