Maxillofacial Deformity In Patients Of Mixed Dentition With Congenital Muscular Torticollis

Many factors could lead to malocclusions during growth and development. As the only supporting structure, the neck inevitably plays a very important role in the craniofacial development. Torticollis is a common congenital anomaly with varied incidence, ranging from 0.3 percent to 1.9 percent of new births, and congenital muscular torticollis is the most common clinicopathological finding in torticollis. Patients with congenital muscular torticollis present with a twisting of the neck to one side, and tilting of the head toward the affected side with a fibrotic and shortened sternocleidomastoid muscle. It includes most of the anomalies of neck, such as muscles and postures. Therefore , it is very helpful and important to study the craniofacial symmetry of the patients with congenital muscular torticollis ,and to evaluate the relationship between the neck and craniofacial structure, so as to discuss what effects the structure and function of neck have on the growth and development of cranioface. At present, almost all of the scholars who have studied the craniofacial symmetry of the patients with congenital muscular torticollis are plastic surgeons, and their aims are all to evaluate the outcomes after a type of surgery, which makes their measurements too rough. This study evaluates the craniofacial symmetry of the patients with congenital muscular torticollis through the detailed measurements on the angles and distances between the special selected marks and referrence lines, and to seek the correlationship between the neck and craniofacial structure, and try to discover what effects the structure and function of neck have on the growth and development of cranioface. We hope to find the differences, and then provide a part of theoretic base on the craniofacial growth and development.Methods and ResultsA total of 20 patients with congenital muscular torticollis from 6 to 12 years of age were included. Posteroanterior cephalometric radiographs were taken to analyze craniofacial asymmetry.Part one: Mandibular symmetry evaluation. On the Posteroanterior cephalometric radiographs, measurements were done. And the symmetry of mandible was analyzed by using paired t-test. The results showed that the mandibular asymmetry occurred in patients with congenital muscular torticollis, characterized by the deviation of chin point to the affected side. On the one hand, compared with the contralateral side, the length of the ipsilateral mandibular body was smaller. However, no significant differences of the length of the mandibular branch as well as the width and height of condyle between both sides were found. On the other hand, in patients with congenital muscular torticollis, the positions of mandible landmarks on both sides changed asymmetrically.Part two: Midfacial symmetry evaluation. Paired t-test was used to analyze the symmetry of the midface , and independent t-test was used to evaluate the deviations of mandibular and maxillary midline. The results showed that the median lines of midface and lower face both deviated to the affected side. Compared with the contralateral side, the face height, the maxillary vertical height on the affected side were smaller. While the development of mastoid process was obviously superior to the contralateral side. In the analysis of position symmetry, we detected that on the affected side, the positions of condyle and zygomatic arch were more outward than the contralateral side, with the zygomatic arch relatively recessed to temple.Conclusions1. In patients of mixed dentition with congenital muscular torticollis, the structural and functional abnormality of the neck can result in different growth between two sides of maxilloface, which leads to the change of maxillofacial stucture and morphous.2. In patients of mixed dentition with congenital muscular torticollis, the mandibular and maxillary vertical height on the affected side are both smaller than the contralateral side .While there is no significant difference with the maxillary horizontal width between two sides, the mandibular horizontal width on the affected side is inferior to the contralateral side, with the mandibular rotation to the affected side, which worsens the asymmetry between two sides. 3. zygoma on the affected side grows outward more than the contralateral side, but its increasing amount is less the neighboring structure such as the temple, so the zygoma on the affected side seems recessed.