A Simple and Descriptive Assessment of Morphology Based on the Horizontal Plane of the Pediatric Head and Creation of a Normative Database in Japanese Children 6 Years Old and under: Horizontal Vector Analysis.

We herein introduce horizontal vector analysis, a simple method for assessing cranial morphology based on measurement of the head's horizontal plane, and use this method to establish normal cranial morphology in Japanese children Computed tomography scans taken in 2010-2019 in healthy Japanese children aged ≤ 6 years. The two measurement planes were parallel to the orbitomeatal plane: namely, a plane passing through the dorsum sellae (DS) and the plane superior to that with the maximal area (Max plane). A protractor was used to circumferentially measure the lengths from the central point to the outer surface of the skull. A total of 487 images were extracted. The distances between the DS and Max planes were consistently almost 30 mm for each age group, so we fixed the Max plane as the plane 30 mm superior to the DS plane. Finally, we established datasets of normal values for each age group and sex. Using these norms, perioperative evaluation of various cranial deformities could be performed more easily and circumstantially.

Growth Curves for Intracranial Volume and Two-dimensional Parameters for Japanese Children without Cranial Abnormality: Toward Treatment of Craniosynostosis.

In the management of patients with craniosynostosis, it is important to understand growth curve of the normal cranium. Although three-dimensional (3D) computed tomography (CT) images taken in thin slices are easily available nowadays, data on the growth curves of intracranial volume (ICV), cranial length, cranial width, and cranial height in the normal cranium are mainly based on older studies using radiography, and there are insufficient reports using CT images especially taken in thin slices. The purpose of this study was to establish growth curves in the normal cranium of Japanese children using thin-slice images. Cranial images of 106 subjects (57 males, 49 females; aged 0-83 months) without significant cranial abnormalities were retrospectively analyzed. Using thin-slice CT images, the ICV and two-dimensional parameters such as cranial length, cranial width, and cranial height were measured by iPlan, followed by generating growth curves and calculating cephalic index (CI). ICV calculated from thin-slice CT images was compared with that obtained by substituting two-dimensional parameters into Mackinnon formula. The ICV growth curves for males and females were similar in shape. As with the ICV, the two-dimensional parameters increased most rapidly in the first year after birth. There was no significant difference in CI between the sexes or among any age groups. ICV calculated from thin-slice 3D CT images was 60% of that obtained from Mackinnon formula. These data will enable us to compare these specific measurements in craniosynostosis patients directly with those of normal children, which will hopefully help in managing these patients.

Morphological improvement after multi-directional cranial distraction osteogenesis procedure for syndromic craniosynostosis.

The multidirectional cranial distraction osteogenesis (MCDO) procedure, which uses an external distraction device, enables tailor-made distraction in an arbitrary direction, eliminating the disadvantage of unidirectional distraction with an internal distraction device. Multiple-suture synostosis cases for syndromic craniosynostosis patients are better indicated for this procedure. Here the authors describe seven cases in which the MCDO procedure was used to treat syndromic craniosynostosis. In each case, the MCDO procedure and postoperative distraction, with reference to midsagittal vector analysis of normal morphology in Japanese children, resulted in morphological improvement. The video can be found here: https://vimeo.com/519006555.

Utilization of a Simple Surgical Guide for Multidirectional Cranial Distraction Osteogenesis in Craniosynostosis.

BACKGROUND: Multidirectional cranial distraction osteogenesis (MCDO) can achieve a desired shape for deformities of the cranium. In the past, visual estimation was used to reflect on the actual skull, but it was time-consuming and inaccurate. Here we demonstrate an effective osteotomy navigation method using surgical guides made from a dental impression silicone. METHODS: Seven patients who underwent MCDO between August 2013 and September 2016 were included in the study. Five cases involved utilization of the surgical guide for osteotomy. Three-dimensional (3D) printed cranium models were made using 3D computed tomography (3DCT) imaging data and dental impression silicone sheets were molded using the printed cranium models. These surgical guides were sterilized and used for intraoperative osteotomy design. Vertical distance between nasion/porion and osteotomy lines were calculated using 3D printed cranial models and postoperative 3DCT images to assess reproducibility. RESULTS: The average surgical time/design time was 535/37.0 minutes for the nonsurgical guide group and 486.8/11.8 minutes for the surgical guide group (SG).Treatment using the surgical guide was significantly shorter in terms of operative time and time required for design. For the vertical distance comparison, the average distance was 5.7mm (SD = 0.3) in the non-SG and 2.5mm (SD = 0.44) in the SG, and SG was more accurate. CONCLUSIONS: Shorter operative times and higher reproducibility rates could be achieved by using the proposed surgical guide, which is accurate, low-cost, and easily accessible.

Traumatic Globe Luxation with Complete Optic Nerve Transection Caused by Heavy Object Compression.

Traumatic eyeball luxation is a rare clinical condition with a dramatic presentation. Here, we describe a unique case of traumatic globe luxation and complete optic nerve transection caused by heavy object compression. A 45-year-old male automobile mechanic was injured when a truck slipped from its supports, crushing his head and face. On arrival, his right eyeball was obviously displaced anteriorly and he had no light perception. Computed tomography revealed complex frontal bone and facial fractures with underlying brain contusion in addition to complete transection of the right optic nerve. The patient was successfully treated using a multidisciplinary approach.

Determination of reference values for normal cranial morphology by using mid-sagittal vector analysis in Japanese children.

Mid-Sagittal Vector Analysis (MSVA) is a method of measuring the distance from a defined central point on the skull surface in the entire mid-sagittal plane and provides a clear description of the lateral view of the skull. We used a series of images of normal skulls of Japanese children to determine normal MSVA values. For this cross-sectional study, we first constructed a database of head CT and MRI images of children aged 0-6 years (41.5 ± 24.9 month (mean ± SD)) who showed no abnormality of cranial development and growth at the time of imaging. Measurement errors due to lateral shifting of the sagittal plane during MSVA were examined, CT and MRI images taken in the same patients at the same time were compared, and measurement differences were examined. Finally, MSVA was carried out, and the mean of the measured values was calculated according to age group. Two hundred ninety-five images were included in the database. When the lateral shifting of the sagittal plane was within 4 mm from the true mid-sagittal plane, the mean errors were less than 1 mm at all measurement points. Between the CT and MRI images from the same patients, most differences in MSVA values were within ±1 mm. These differences were thus acceptable for use in clinical settings. After the above verifications, 220 images were extracted for determination of normal MSVA values. We established a normal dataset of MSVA for Japanese children that can be used effectively for preoperative diagnosis, surgery planning, and postoperative assessment of cranial deformities.