Human skull base asymmetry analysis / Análisis de asimetría de la base de cráneo humano

SUMMARY: Since the asymmetry is generally accepted entity which can be detected on human skulls, the goal of this study was to evaluate the presence and degree of skull base asymmetry and analyze it in relation to sex. The study included 60 skulls. Gender identification was estimated according to the external occipital protuberance, mastoid process, supraorbital margin and glabella. The asymmetry was assessed by analyzing the distance from the bilateral foramina (foramen ovale, foramen spinosum, carotid canal, foramen stylomastoideum) to the pharyngeal tubercle. Digital data were processed in the ImageJ software. The skull base asymmetry was found in all samples. Significant difference between the sides was found for the foramen ovale (p=.01). There was no significant difference in the skull base asymmetry with respect to sex. The highest index of asymmetry (7.38 %) was found in carotid canal and the lowest (5.22%) was detected in relation to the foramen stylomastoideum. By comparing the index of asymmetry between the genders significant difference occurs for the carotid canal (p=.02). Skull base asymmetry was confirmed in our study. Oval foramen showed a significant degree of asymmetry. Knowledge of the variability of the skull base is the basis for an clinical and radiological evaluation of its changes.

RESUMEN: Debido a que la asimetría detectada en cráneos humanos es aceptada generalmente, el objetivo de este estudio fue evaluar la presencia y el grado de asimetría de la base del cráneo y analizarla en relación con el sexo. En este estudio fueron incluidos 60 cráneos. El sexo fue determinado de acuerdo con la protuberancia occipital externa, el proceso mastoideo, el margen supraorbital y la glabela. La asimetría se evaluó analizando la distancia desde los forámenes bilaterales (foramen oval, foramen espinoso, canal carotídeo, foramen estilomastoideo) hasta el tubérculo faríngeo. Los datos digitales fueron procesados en software ImageJ. La asimetría de la base de cráneo se observó en todas las muestras. Se encontró una diferencia significativa entre los lados para el foramen oval (p = ,01). No hubo diferencias significativas en la asimetría de la base de cráneo con respecto al sexo. El índice más alto de asimetría (7,38%) se encontró en el canal carotídeo y el más bajo (5,22 %) se detectó en relación con el foramen estilomastoideo. Al comparar el índice de asimetría entre los sexos, se produce una diferencia significativa en el canal carotídeo (p = 0,02). La asimetría de la base de cráneo se confirmó en nuestro estudio. El foramen oval mostró un grado significativo de asimetría. El conocimiento de la variabilidad de la base del cráneo es importante durante la evaluación clínica y radiológica.

Quantifying normal head form and craniofacial asymmetry of elementary school students in Taiwan.

BACKGROUND: Defining three-dimensional (3D) normal craniofacial morphology in healthy children could provide craniofacial surgeons a reference point to assess disease, plan surgical reconstruction, and evaluate treatment outcome. The purposes of this study were to report normal craniofacial form and quantify craniofacial asymmetry of healthy children in Taiwan by implementing the 3D stereophotogrammetry technique. METHODS: Healthy Taiwanese elementary school children (n = 652) aged 6-12 years with no known craniofacial anomaly were recruited. After the 3dMD scanning procedure, 32 landmarks were manually placed on the 3D cranial images. Thin plate spline algorithm based on landmarks and closest point matching was applied to deform a symmetric 3D template into the scale of each scanned images. Skull asymmetry and facial asymmetry were calculated using 3dMD vultus and MATLAB. Average head shape models were also presented. RESULTS: Overall, the mean head transverse width, height, anteroposterior length, and circumferences were 163.02, 220.79, 179.07, and 526.55 mm, respectively. On average, the skull asymmetry and facial asymmetry were 2.47 ± 1.26 mm and 0.96 ± 0.53 mm, respectively, with no significant (all p > 0.05) differences found when comparing males and females. In the average head shape model, certain craniofacial areas on the right side were found to be more protruded than those on the left side. CONCLUSIONS: This study shows that the baseline craniofacial form of the Taiwanese elementary school children is asymmetric with a tendency of more protrusion of the head on the right side.

Homozygous noncanonical splice variant in LSM1 in two siblings with multiple congenital anomalies and global developmental delay.

Two siblings, one male and one female, ages 6 and 13 yr old, have similar clinical features of global developmental delay, multiple congenital anomalies affecting the cardiac, genitourinary, and skeletal systems, and abnormal eye movements. Whole-genome sequencing revealed a homozygous splice variant (NM_014462.3:c.231+4A>C) in LSM1 that segregated with the phenotype in the family. LSM1 has a role in pre-mRNA splicing and degradation. Expression studies revealed absence of expression of the canonical isoform in the affected individuals. The Lsm1 knockout mice have a partially overlapping phenotype that affects the brain, heart, and eye. To our knowledge, LSM1 has not been associated with any human disorder; however, the tissue expression pattern, gene constraint, and the similarity of the phenotype in our patients and the knockout mice models suggest it has a role in the development of multiple organ systems in humans.

Craniofacial Asymmetry from One to Three Years of Age: A Prospective Cohort Study with 3D Imaging.

Deformational plagiocephaly (DP) is considered a risk factor for facial asymmetry. This cohort-based, prospective, follow-up study used three-dimensional (3D) stereophotogrammetry to assess the development of facial asymmetry in a normal birth cohort and to investigate the impact of DP on facial asymmetry for the age range of one to three years. The study sample consisted of 75 children: 35 girls (47%) and 40 (53%) boys recruited from Oulu University Hospital. A total of 23 (31%) subjects had a history of DP in infancy. 3D facial images were obtained at the mean (SD) age of 1.01 (0.04) year old at T1 and 3.02 (0.14) years old at T2. To determine facial asymmetry, both landmark-based and surface-based facial symmetry methods were used. As measured with the surface-based methods, upper facial symmetry improved from T1 to T2 (p < 0.05). As measured with the landmark-based methods, facial symmetry improved on the upper and lower jaw from T1 to T2 (p < 0.05). The asymmetric effect of DP on the upper parts of the face tends to correct spontaneously during growth. Results indicate that previous DP does not seem to transfer to facial or occlusal asymmetry at the age of three years old.

Breastfeeding infants with congenital torticollis.

Infants with unilateral sternocleidomastoid tension and associated craniofacial, spinal, and hip asymmetries may feed poorly. Anatomic and muscular asymmetry stress both biomechanics and state control, increasing the potential for difficulty latching and sucking. A combination of positioning modifications to allow the infant to maintain his or her comfortable head tilt and turn, supportive techniques to restore alignment of oral structures, and handling techniques to help activate the weak contralateral muscles have been effective in the author's practice. Lactation consultants can promote positioning and muscle activation strategies and encourage physical therapy referrals for infants who do not respond promptly to reduce the risk of craniofacial deformity and developmental problems.

A new three-dimensional analysis of asymmetry for patients with craniofacial syndromes.

OBJECIVES: The use of three-dimensional computed tomography (3D-CT) analyses represents a substantial improvement in planning treatment. The aim of this study is to introduce a new three-dimensional (3D) analysis of clinical value for evaluating asymmetry in cases of craniofacial syndrome. SUBJECTS AND METHODS: Virtual 3D models were reconstructed from CT images of 62 normal subjects (35 males and 27 females), more than 18 years old. Measurements of asymmetrical skeletal and dentoalveolar relationships were evaluated and standardized data obtained. The feasibility of the new 3D craniofacial analysis was then evaluated on one patient with severe maxillomandibular asymmetry in the form of hemifacial microsomia. RESULTS: Standardized 3D data from the analysis were obtained and classified into 6 maxillary measurements, eight mandibular measurements and seven dentoalveolar process measurements. No significant differences were found between males and females (U-Mann-Whitney test, P > 0.05). Useful data of clinical value was provided for planning orthodontic and surgical treatment of asymmetries, as well as a diagnostic chart. CONCLUSION: This method is useful for the clinical evaluation of asymmetry in craniofacial syndromes. The use of 3D analysis facilitates surgical and orthodontic treatment planning.

Craniofacial Asymmetry in Congenital Muscular Torticollis Patients: A Study using Cephalometry / 대한정형외과학회잡지

Purpose: To propose an objective method for evaluating the craniofacial asymmetry in congenital muscular torticollis patients, and to determine the correlation between the craniofacial asymmetry and clinical parameters such as age and the limitation of neck motion. Materials and Methods: Forty eight patients with congenital muscular torticollis, who underwent cephalometry for an evaluation, were enrolled in this study. The craniofacial curvature on the coronal plane, calvarial asymmetry, and mastoid process length were analyzed on the radiograph of the cephalometry. These radiographic measurements were analyzed to determine the correlation between the craniofacial asymmetry and clinical parameters. Results: The craniofacial axis was tilted to the affected side by 5.2degrees+/-2.8degrees. The skullbase axis was tilted to the affected side by 2.6degrees+/-2.6degrees, and the mandible axis was tilted to the affected side by 1.0degrees+/-2.3degrees. The difference in the mastoid process length from the skullbase was 7.0%+/-8.5%. The calvarial width from the vertical midline was 15.4%+/-11.6% larger in the affected side. In patients older than 5 years, the mandibular tilting angle (p=0.017) and the length of the mastoid process (p=0.007) were greater than those of the younger patients. Conclusion: We proposed a new objective method for quantifying the craniofacial asymmetry in congenital muscular torticollis patients. This method confirmed the patients to have an angular deformity and asymmetry in the craniofacial bone.

A posteroanterior roentgenocephalometric study of skeletal craniofacial asymmetric patients / 대한치과교정학회지

This study was undertaken to investigate the degree of asymmetry in each part of the head in skeletal craniofacial asymmetric patients, and secondarily to determine the nature of difference existed between asymmetric patients and normal persons. The subjects consisted of 49 asymmetric adult patients and 52 normal adults, and the average ages were 21 years 5 months and 23 years 5 months, respectively. The computerized analyses of 33 linear measurements, 12 angular. measurements, and 8 surface areas from posteroanterior cephalometric radiograph were carried out. The conclusions were as follows; 1. Asymmetry was a common finding in both normal and asymmetric group. 2. When the analyses were undertaken after the head was divided into 3 parts anteroposteriorly and superoinferiorly in the asymmetric patients, there were significant asymmetries in all parts excepts in the cranial base region. 3. When the analyses were undertaken after the head was divided into respective 3 parts anteroposteriorly in the asymmetric patients, the more posterior part showed relative stability than the more anterior part. 4. When the analyses were undertaken after the head was divided into 3 parts superoinferiorly in the asymmetric patients, the more superior part showed relative stability than the more inferior part. 5. Twelve variables indicating asymmetry were selected and the highest ranked variable was Me-Mid-sagittal reference line.