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.

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.

Efficacy of Honeycomb TCP-induced Microenvironment on Bone Tissue Regeneration in Craniofacial Area.

Artificial bone materials that exhibit high biocompatibility have been developed and are being widely used for bone tissue regeneration. However, there are no biomaterials that are minimally invasive and safe. In a previous study, we succeeded in developing honeycomb ß-tricalcium phosphate (ß-TCP) which has through-and-through holes and is able to mimic the bone microenvironment for bone tissue regeneration. In the present study, we investigated how the difference in hole-diameter of honeycomb ß-TCP (hole-diameter: 75, 300, 500, and 1600 µm) influences bone tissue regeneration histologically. Its osteoconductivity was also evaluated by implantation into zygomatic bone defects in rats. The results showed that the maximum bone formation was observed on the ß-TCP with hole-diameter 300µm, included bone marrow-like tissue and the pattern of bone tissue formation similar to host bone. Therefore, the results indicated that we could control bone tissue formation by creating a bone microenvironment provided by ß-TCP. Also, in zygomatic bone defect model with honeycomb ß-TCP, the result showed there was osseous union and the continuity was reproduced between the both edges of resected bone and ß-TCP, which indicated the zygomatic bone reproduction fully succeeded. It is thus thought that honeycomb ß-TCP may serve as an excellent biomaterial for bone tissue regeneration in the head, neck and face regions, expected in clinical applications.

Analysis of 10-Year Training Results of Medical Students Using the Microvascular Research Center Training Program.

Background In this article, we reviewed the training results of medical students using the Microvascular Research Center Training Program (MRCP), and proposed an ideal microsurgical training program for all individuals by analyzing the training results of medical students who did not have any surgical experience. Methods As of 2015, a total of 29 medical students completed the MRCP. In the most recent 12 medical students, the number of trials performed for each training stage and the number of rats needed to complete the training were recorded. Additionally, we measured the operating time upon finishing stage 5 for the recent six medical students after it became a current program. Results The average operating time upon finishing stage 5 for the recent six medical students was 120 minutes ± 11 minutes (standard deviation [SD]). The average vascular anastomosis time (for the artery and vein) was 52 minutes ± 2 minutes (SD). For the most recent 12 medical students, there was a negative correlation between the number of trials performed in the non-rat stages (stages 1-3) and the number of rats used in the rat stages (stages 4-5). Conclusion Analysis of the training results of medical students suggests that performing microsurgery first on silicon tubes and chicken wings saves animals' lives later during the training program. We believe that any person can learn the technique of microsurgery by performing 7 to 8 hours of training per day over a period of 15 days within this program setting.

Histologic Evaluation of Lymphaticovenular Anastomosis Outcomes in the Rat Experimental Model: Comparison of Cases with Patency and Obstruction.

BACKGROUND: Lymphaticovenular anastomosis plays an important role in the surgical treatment of lymphedema. The outcomes of lymphaticovenular anastomosis are evaluated based on changes in edema; however, isolated assessment of the anastomosis itself is difficult. The authors used an animal experimental model to conduct a detailed examination of histologic changes associated with lymphaticovenular anastomosis and determined the factors important for success. METHODS: The experimental lymphaticovenular anastomosis model was created using lumbar lymph ducts and iliolumbar veins of Wistar rats. The authors performed anastomosis under a microscope and reviewed postoperative histologic changes using optical and electron microscopy. In addition, electron microscopy and histology were used for detailed examination of the area in the vicinity of the anastomotic region in cases with patency and obstruction. RESULTS: The patency rates immediately after, 1 week after, and 1 month after lymphaticovenular anastomosis were 100 percent (20 of 20), 70 percent (14 of 20), and 65 percent, respectively. A detailed examination of the anastomotic region with electron microscopy revealed that, in cases with patency, there was no notable transformation of the endothelial cells, which formed a smooth layer. In contrast, in obstruction cases, the corresponding region of the endothelium was irregular in structure. CONCLUSIONS: Vessel obstruction after lymphaticovenular anastomosis may be associated with irregular arrangement of the endothelial layer, leading to exposure of subendothelial tissues and platelet formation. One part of the postoperative changes after anastomosis and a cause of obstruction were elucidated in this study. The authors' results may enable improvements in lymphaticovenular anastomosis by translating back to real clinical operations.

Mechanical Stretch on Human Skin Equivalents Increases the Epidermal Thickness and Develops the Basement Membrane.

All previous reports concerning the effect of stretch on cultured skin cells dealt with experiments on epidermal keratinocytes or dermal fibroblasts alone. The aim of the present study was to develop a system that allows application of stretch stimuli to human skin equivalents (HSEs), prepared by coculturing of these two types of cells. In addition, this study aimed to analyze the effect of a stretch on keratinization of the epidermis and on the basement membrane. HSEs were prepared in a gutter-like structure created with a porous silicone sheet in a silicone chamber. After 5-day stimulation with stretching, HSEs were analyzed histologically and immunohistologically. Stretch-stimulated HSEs had a thicker epidermal layer and expressed significantly greater levels of laminin 5 and collagen IV/VII in the basal layer compared with HSEs not subjected to stretch stimulation. Transmission electron microscopy revealed that the structure of the basement membrane was more developed in HSEs subjected to stretching. Our model may be relevant for extrapolating the effect of a stretch on the skin in a state similar to an in vivo system. This experimental system may be useful for analysis of the effects of stretch stimuli on skin properties and wound healing and is also expected to be applicable to an in vitro model of a hypertrophic scar in the future.

Evaluation of the microvascular research center training program for assessing microsurgical skills in trainee surgeons.

BACKGROUND: We established the Microvascular Research Center Training Program (MRCP) to help trainee surgeons acquire and develop microsurgical skills. Medical students were recruited to undergo the MRCP to assess the effectiveness of the MRCP for trainee surgeons. METHODS: Twenty-two medical students with no prior microsurgical experience, who completed the course from 2005 to 2012, were included. The MRCP comprises 5 stages of training, each with specific passing requirements. Stages 1 and 2 involve anastomosing silicone tubes and blood vessels of chicken carcasses, respectively, within 20 minutes. Stage 3 involves anastomosing the femoral artery and vein of live rats with a 1-day patency rate of >80%. Stage 4 requires replantation of free superficial inferior epigastric artery flaps in rats with a 7-day success rate of >80%. Stage 5 involves successful completion of one case of rat replantation/transplantation. We calculated the passing rate for each stage and recorded the number of anastomoses required to pass stages 3 and 4. RESULTS: The passing rates were 100% (22/22) for stages 1 and 2, 86.4% (19/22) for stage 3, 59.1% (13/22) for stage 4, and 55.0% (11/20) for stage 5. The number of anastomoses performed was 17.2±12.2 in stage 3 and 11.3±8.1 in stage 4. CONCLUSIONS: Majority of the medical students who undertook the MRCP acquired basic microsurgical skills. Thus, we conclude that the MRCP is an effective microsurgery training program for trainee surgeons.

Phantom erectile penis after sex reassignment surgery.

Between January 2001 and December 2007, we performed vaginoplasty as sex reassignment surgery in a total of 14 male-to-female transsexual (MTFTS) patients [1]. Several complications occurred such as partial flap necrosis, rectovaginal fistula formation and hypersensitivity of the neoclitoris. Just after the operation, some patients feel that their penises still exist, but by several weeks postoperatively, this sensation has disappeared. Herein we report a case of MTFTS in whom the sensation of a phantom erectile penis persisted for much longer.