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Foley, Michael J., Patrick S. Cottler, Silvia S. Blemker, Arlen D. Denny, and Jonathan S. Black. "Computer Simulation and Optimization of Cranial Vault Distraction." Cleft Palate-Craniofacial Journal 55, no. 3 (December 14, 2017): 356–61. http://dx.doi.org/10.1177/1055665617738999.
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Objective: The objective of this study was to validate the proof of concept of a computer-simulated cranial distraction, demonstrating accurate shape and end volume. Design: Detailed modeling was performed on pre- and postoperative computed tomographic (CT) scans to generate accurate measurements of intracranial volume. Additionally, digital distraction simulations were performed on the preoperative scan and the resultant intracranial volume and shape were evaluated. Setting: Tertiary Children’s Hospital. Patients, Participants: Preoperative and postoperative CT images were used from 10 patients having undergone cranial distraction for cephalocranial disproportion. Interventions: None; computer simulation. Main Outcome Measure: Computer simulation feasibility of cranial vault distraction was demonstrated through creation of digital osteotomies, simulating distraction through translating skull segments, followed by simulated consolidation. Accuracy of the model was evaluated through comparing the intracranial volumes of actual and simulated distracted skulls. Results: The developed digital distraction simulation was performed on the CT images of 10 patients. Plotting the relationship between the actual and simulated postdistraction volumes for the 10 patients yielded a slope of 1.0 and a correlation coefficient of 0.99. The average actual resultant volume change from distraction was 77.0 mL, compared to a simulated volume change of 76.9 mL. Conclusions: Digital simulation of cranial distraction was demonstrated through manipulation of the CT images and confirmed by comparing the actual to simulated volume change. This process may provide objective data in designing an individual distraction plan to optimize volume expansion and resultant cranial shape as well as patient education.
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BROWN, NATHAN P., GINA E. BERTOCCI, and DENIS J. MARCELLIN-LITTLE. "DEVELOPMENT OF A CANINE STIFLE COMPUTER MODEL TO EVALUATE CRANIAL CRUCIATE LIGAMENT DEFICIENCY." Journal of Mechanics in Medicine and Biology 13, no. 02 (April 2013): 1350043. http://dx.doi.org/10.1142/s0219519413500437.
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The objective of this study was to develop a three-dimensional (3D) quasi-static rigid body canine pelvic limb computer model simulating a cranial cruciate ligament (CrCL) intact and CrCL-deficient stifle during walking stance to describe stifle biomechanics. The model was based on a five-year-old neutered male Golden Retriever (33 kg) with no orthopedic or neurologic disease. Skeletal geometry and ligament anatomy determined from computed tomography (CT), optimized muscle forces, motion capture kinematics, and force platform ground reaction forces were used to develop the model. Ligament loads, tibial translation, tibial rotation, and femoromeniscal contact forces were compared across the intact and CrCL-deficient stifle. The CrCL was found to be the primary intact stifle load-bearing ligament, and the caudal cruciate ligament was the primary CrCL-deficient stifle load-bearing ligament. Normalized tibial translation and rotation were 0.61 mm/kg and 0.14 degrees/kg, respectively. Our model confirmed that the CrCL stabilizes the intact stifle and limits tibial translation and rotation. Model verification was confirmed through agreement with experimentally measured kinematics and previous in vivo, in vitro, and mathematical model studies. Parametric analysis indicated outcome measure sensitivity to ligament pre-strain. Computer modeling could be useful to further investigate stifle biomechanics associated with surgical stabilization techniques.
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Morrison, D. A., D. T. Guy, R. E. Day, and G. Y. F. Lee. "Simultaneous repair of two large cranial defects using rapid prototyping and custom computer-designed titanium plates: a case report." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 225, no. 11 (September 19, 2011): 1108–12. http://dx.doi.org/10.1177/0954411911422766.
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Custom titanium cranioplasty plates, manufactured by a variety of techniques, have been used to repair a range of cranial defects. The authors present a case where two relatively large, adjacent cranial defects were repaired by custom computer-designed titanium plates. The two plates were designed and fabricated simultaneously using a unique methodology. A 28-year-old woman underwent a corpus callosotomy for medically intractable epilepsy. The surgery was complicated by unexpected haemorrhage which necessitated a second craniotomy. Subsequent deep infection required the removal of bilateral bone flaps, presenting a challenge in the reconstruction of extensive, bilateral but asymmetrical cranial defects. The patient underwent a head computed tomography scan, from which a rapid-prototype model of the skull was produced. The surfaces for the missing cranial segments were generated virtually using a combination of software products and two titanium plates that followed these virtual contours were manufactured to cover the defects. The cranioplasty procedure to implant both titanium cranial plates was performed efficiently with no intra-operative complications. Intra-operatively, an excellent fit was achieved. The careful planning of the plates enhanced the relative ease with which the cranial defects were repaired with an excellent cosmetic outcome.
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Tsai, Fu-Hui, and Han-Yi Cheng. "Evaluation of Structural and Biomechanical Characterization of Implant for Cranial Restoration." Journal of Biomaterials and Tissue Engineering 9, no. 7 (July 1, 2019): 898–903. http://dx.doi.org/10.1166/jbt.2019.2075.
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The objective this research was to investigate the biomechanical properties of various structures and thicknesses of implants for cranial restoration. A three-dimensional (3D) printing (3DP) technique has been applied in factories for several decades, but it was only recently introduced to the dental field less than 10 years ago. The structures of pre-shaped cranial mesh implants are critical factors for clinical applications. Many previous studies used finite element models to investigate for implants, but few examined a 3D model for pre-shaped cranial mesh implants with different structures and thicknesses. 3D cranial models were reconstructed using computer tomography to simulate preshaped cranial mesh implants under physical impacts. Data indicated that the stress significantly decreased when implants with greater thicknesses were used. Moreover, the implant with a circular structure created a relatively smaller stress that was approximately 7% lower compared to the implant with a triangular structure. As described above, the results of the present study demonstrate that 3DP-Ti is a reliable material of implants for cranial restoration.
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Hendricks, Benjamin K., Akash J. Patel, Jerome Hartman, Mark F. Seifert, and Aaron Cohen-Gadol. "Operative Anatomy of the Human Skull: A Virtual Reality Expedition." Operative Neurosurgery 15, no. 4 (September 17, 2018): 368–77. http://dx.doi.org/10.1093/ons/opy166.
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Abstract INTRODUCTION The human cranial vault possesses an incredible, complex anatomical intricacy. Bridging the divide between 2-dimensional (2D) learning resources and the 3-dimensional (3D) world in which the anatomy becomes clinically relevant poses an intellectual challenge. Advances in computer graphics and modelling technologies have allowed increasingly accurate and representative resources to supplement cadaveric dissection specimens. OBJECTIVE To create accurate virtual models of all cranial bones to augment education, research, and clinical endeavours. METHODS Through a careful analysis of osteological specimens and high-resolution radiographic studies, a highly accurate virtual model of the human skull was created and annotated with relevant anatomical landmarks. RESULTS The skull was divided into 6 major segments including frontal, ethmoid, sphenoid, temporal, parietal, and occipital bones. These bones were thoroughly annotated to demonstrate the intricate anatomical features. CONCLUSION This virtual model has the potential to serve as a valuable resource for educational, research, and clinical endeavours, and demonstrates the significance of advances in computer modelling that can contribute to our understanding of neurosurgical anatomical substrates.
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Shen, Shang-Hang, Aij-Lie Kwan, Bo-Liang Wang, Jian-Feng Guo, Guo-Wei Tan, Si-Fang Chen, Xi-Yao Liu, Feng Liu, Ming Cai, and Zhan-Xiang Wang. "Reduction cranioplasty with the aid of simulated computer imaging for the treatment of hydrocephalic macrocephaly." Journal of Neurosurgery: Pediatrics 13, no. 2 (February 2014): 133–39. http://dx.doi.org/10.3171/2013.10.peds12573.
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Object The occurrence of hydrocephalic macrocephaly is uncommon. When the condition does occur, it is usually seen in infants and young children. Patients with this disorder have an excessively enlarged head and weak physical conditions. Various surgical techniques of reduction cranioplasty for the treatment of these patients have been reported. In this study, a revised surgical procedure with the aid of simulated computer imaging for the treatment of hydrocephalic macrocephaly is presented. Methods Five cases of hydrocephalic macrocephaly in children ranging in age from 16 to 97 months were reviewed. These patients underwent surgical treatment at The First Affiliated Hospital of Xiamen University over a period of 4 years from January 2007 to January 2011. After physical examination, a 3D computer imaging system to simulate the patient's postoperative head appearance and bone reconstruction was established. Afterward, for each case an appropriate surgical plan was designed to select the best remodeling method and cranial shape. Then, prior to performing reduction remodeling surgery in the patient according to the computer-simulated procedures, the surgeon practiced the bone reconstruction technique on a plaster head model made in proportion to the patient's head. In addition, a sagittal bandeau was used to achieve stability and bilateral symmetry of the remodeled cranial vault. Each patient underwent follow-up for 6–32 months. Results Medium-pressure ventriculoperitoneal shunt surgery or shunt revision procedures were performed in each patient for treating hydrocephalus, and all patients underwent total cranial vault remodeling to reduce the cranial cavity space. Three of the 5 patients underwent a single-stage surgery, while the other 2 patients underwent total cranial vault remodeling in the first stage and the ventriculoperitoneal shunt operation 2 weeks later because of unrecovered hydrocephalus. All patients had good outcome with regard to hydrocephalus and macrocephaly. Conclusions There are still no standard surgical strategies for the treatment of hydrocephalic macrocephaly. Based on their experience, the authors suggest using a computer imaging system to simulate a patient's postoperative head appearance and bone reconstruction together with total cranial vault remodeling with shunt surgery in a single-stage or 2-stage procedure for the successful treatment of hydrocephalic macrocephaly.
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Kakizawa, Yukinari, Kazuhiro Hongo, and Albert L. Rhoton. "Construction of a Three-Dimensional Interactive Model of the Skull Base and Cranial Nerves." Neurosurgery 60, no. 5 (May 1, 2007): 901–10. http://dx.doi.org/10.1227/01.neu.0000255422.86054.51.
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Abstract OBJECTIVE The goal was to develop an interactive three-dimensional (3-D) computerized anatomic model of the skull base for teaching microneurosurgical anatomy and for operative planning. METHODS The 3-D model was constructed using commercially available software (Maya 6.0 Unlimited; Alias Systems Corp., Delaware, MD), a personal computer, four cranial specimens, and six dry bones. Photographs from at least two angles of the superior and lateral views were imported to the 3-D software. Many photographs were needed to produce the model in anatomically complex areas. Careful dissection was needed to expose important structures in the two views. Landmarks, including foramen, bone, and dura mater, were used as reference points. RESULTS The 3-D model of the skull base and related structures was constructed using more than 300,000 remodeled polygons. The model can be viewed from any angle. It can be rotated 360 degrees in any plane using any structure as the focal point of rotation. The model can be reduced or enlarged using the zoom function. Variable transparencies could be assigned to any structures so that the structures at any level can be seen. Anatomic labels can be attached to the structures in the 3-D model for educational purposes. CONCLUSION This computer-generated 3-D model can be observed and studied repeatedly without the time limitations and stresses imposed by surgery. This model may offer the potential to create interactive surgical exercises useful in evaluating multiple surgical routes to specific target areas in the skull base.
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Alshareef, Mohammed, Ahmed Alshareef, Tyler Vasas, Aakash Shingala, Jonathan Cutrone, and Ramin Eskandari. "Pediatric Cranioplasty Using Hydroxyapatite Cement: A Retrospective Review and Preliminary Computational Model." Pediatric Neurosurgery 57, no. 1 (November 30, 2021): 40–49. http://dx.doi.org/10.1159/000520954.
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Introduction: Cranioplasty is a standard technique for skull defect repair. Restoration of cranial defects is imperative for brain protection and allowing for homeostasis of cerebral spinal fluid within the cranial vault. Calcium phosphate hydroxyapatite (HA) is a synthetic-organic material that is commonly used in cranioplasty. We evaluate a patient series undergoing HA cement cranioplasty with underlying bioresorbable mesh for various cranial defects and propose a preliminary computational model for understanding skull osteointegration. Methods: A retrospective review was performed at the institution for all pediatric patients who underwent HA cement cranioplasty. Seventeen patients were identified, and success of cranioplasty was determined based on clinical and radiographic follow-up. A preliminary computational model was developed using bone growth and scaffold decay equations from previously published literature. The model was dependent on defect size and shape. Patient data were used to optimize the computational model. Results: Seventeen patients were identified with an average age of 6 ± 5.6 years. Average defect size was 11.7 ± 16.8 cm2. Average time to last follow-up computer tomography scan was 10 ± 6 months. Three patients had failure of cranioplasty, all with a defect size above 15 cm2. The computational model developed shows a constant decay rate of the scaffold, regardless of size or shape. The bone growth rate was dependent on the shape and number of edges within the defect. Thus, a star-shaped defect obtained a higher rate of growth than a circular defect because of faster growth rates at the edges. The computational simulations suggest that shape and size of defects may alter success of osteointegration. Conclusion: Pediatric cranioplasty is a necessary procedure for cranial defects with a relatively higher rate of failure than adults. Here, we use HA cement to perform the procedure while creating a preliminary computational model to understand osteointegration. Based on the findings, cranioplasty shape may alter the rate of integration and lead to higher success rates.
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Liao, Yuan-Lin, Chia-Feng Lu, Yung-Nien Sun, Chieh-Tsai Wu, Jiann-Der Lee, Shih-Tseng Lee, and Yu-Te Wu. "Three-dimensional reconstruction of cranial defect using active contour model and image registration." Medical & Biological Engineering & Computing 49, no. 2 (December 3, 2010): 203–11. http://dx.doi.org/10.1007/s11517-010-0720-0.
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Lee, Min Jin, Helen Hong, and Kyu Won Shim. "Quantitative Assessment of Shape Deformation of Regional Cranial Bone for Evaluation of Surgical Effect in Patients with Craniosynostosis." Applied Sciences 11, no. 3 (January 22, 2021): 990. http://dx.doi.org/10.3390/app11030990.
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Surgery in patients with craniosynostosis is a common treatment to correct the deformed skull shape, and it is necessary to verify the surgical effect of correction on the regional cranial bone. We propose a quantification method for evaluating surgical effects on regional cranial bones by comparing preoperative and postoperative skull shapes. To divide preoperative and postoperative skulls into two frontal bones, two parietal bones, and the occipital bone, and to estimate the shape deformation of regional cranial bones between the preoperative and postoperative skulls, an age-matched mean-normal skull surface model already divided into five bones is deformed into a preoperative skull, and a deformed mean-normal skull surface model is redeformed into a postoperative skull. To quantify the degree of the expansion and reduction of regional cranial bones after surgery, expansion and reduction indices of the five cranial bones are calculated using the deformable registration as deformation information. The proposed quantification method overcomes the quantification difficulty when using the traditional cephalic index(CI) by analyzing regional cranial bones and provides useful information for quantifying the surgical effects of craniosynostosis patients with symmetric and asymmetric deformities.
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Brown, Nathan P., Gina E. Bertocci, and Denis J. Marcellin-Little. "Canine cranial cruciate ligament deficient stifle biomechanics associated with extra-articular stabilization predicted using a computer model." Veterinary Surgery 46, no. 5 (April 1, 2017): 653–62. http://dx.doi.org/10.1111/vsu.12652.
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Kemmoku, D. T., L. Serenó, J. San, and J. Ciurana. "A novel simplified 3D skull model to predict cranial fracture patterns." International Journal of Computer Integrated Manufacturing 27, no. 10 (September 10, 2013): 927–35. http://dx.doi.org/10.1080/0951192x.2013.834470.
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Mansour, Natalie, Lisa Sobel, Misook Lee, Jose Larumbe, and Eric Stelnicki. "A New Method for the Treatment of Macrocephaly Caused by Hydrocephalus." Cleft Palate-Craniofacial Journal 42, no. 1 (January 2005): 1–6. http://dx.doi.org/10.1597/03-091.1.
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Objective This report will discuss a new surgical technique for treating severe cases of macrocephaly in which the bony architecture is markedly distorted. The procedure relies on several novel surgical tools for its success that have not been previously applied to the treatment of this condition. It utilized the use of contraction osteogenesis devices, resorbable plating systems, and an age- and sex-matched computer-generated skull model, which was derived from a computed tomographic scan as a template for the new calvarium. Results In the case reported, combined use of these technologies allowed for the complete reconstruction of the calvarium down to the level of the cranial base to produce an appropriately sized skull. The skull model created a template onto which bony fragments could be placed and fixated into a normal shape using the resorbable plating system. The contraction osteogenesis devices then allowed for a slow, safe reduction of the hydrocephalus via a ventriculoperitoneal shunt over a period of several days. On completion of the contraction process, the devices served to fixate the calvarium to the cranial base during the period of bone healing. Conclusion The combination of these modalities represents a unique state-of-the-art method for the correction of severe macrocephaly without the risks of intracranial hemorrhage and provides a useful adjunct to the treatment of hydrocephalus.
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Koyama, Toru, Hiroshi Okudera, Hirohiko Gibo, and Shigeaki Kobayashi. "Computer-generated microsurgical anatomy of the basilar artery bifurcation." Journal of Neurosurgery 91, no. 1 (July 1999): 145–52. http://dx.doi.org/10.3171/jns.1999.91.1.0145.
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✓ The authors' goal was to develop a computer graphics model to represent the microsurgical anatomy of the basilar artery (BA) bifurcation and surrounding structures to simulate surgery of a BA bifurcation aneurysm performed via the transsylvian approach.The source of the input data was a variety of publications that showed detailed anatomy of the area. A computer graphics model of the area near the BA bifurcation including relevant structures, such as perforating branches or cranial nerves, was depicted in detail. A BA bifurcation aneurysm was added to the computer graphics model and it was rotated to simulate the transsylvian approach. After the internal carotid artery was displaced using a virtual retractor, the aneurysm was exposed, thus providing an understanding of the three-dimensional surgical orientation of the area.Designing a standard anatomical model on the basis of data culled from a variety of publications and adding morphological changes by using a virtual retractor to displace structures that obstruct the view along a critical path at the base of the brain are useful strategies of computer manipulation for surgical simulation in open microneurosurgery. This methodological tool would be useful in teaching surgical microanatomy and in introducing a new navigational system for virtual reality. Both concept and technical details are discussed.
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Bagudanch, Isabel, María Luisa García-Romeu, Ines Ferrer, and Joaquim Ciurana. "Customized cranial implant manufactured by incremental sheet forming using a biocompatible polymer." Rapid Prototyping Journal 24, no. 1 (January 2, 2018): 120–29. http://dx.doi.org/10.1108/rpj-06-2016-0089.
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Purpose The purpose of this paper is to demonstrate the feasibility of incremental sheet forming (ISF), using the most common variants, single-point incremental forming (SPIF) and two-point incremental forming (TPIF), to produce prototypes of customized cranial implants using a biocompatible polymer (ultrahigh molecular weight polyethylene, UHMWPE), ensuring an appropriate geometric accuracy and cost. Design/methodology/approach The cranial implant is designed based on computerized tomographies (CT) of the patient, converting them into a 3D model using the software InVesalius. To generate the toolpath for the forming operation computer-aided manufacturing (CAM) software is used. Once the cranial implant is manufactured, a 3D scanning system is used to determine the geometric deviation between the real part and the initial design. Findings The results corroborate that it is possible to successfully manufacture a customized cranial implant using ISF, being able to improve the geometric accuracy using the TPIF variant with a negative die. Originality/value This paper is one of the first research works in which a customized cranial implant is successfully manufactured using a flexible technology, ISF and a biocompatible polymer. The use of polymeric implants in cranioplasty is advantageous because of their lightweight, low heat conductivity and mechanical properties similar to bone. Furthermore, the cost of the implant has been calculated considering not only the raw materials and manufacturing time but also the environmental impact, revealing that it is a cheap process with a low lead-time.
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Otake, Yoshito, Naoki Suzuki, Asaki Hattori, Yuko Shigeta, Takumi Ogawa, Shunji Fukushima, Kaoru Kobayashi, and Akihiko Uchiyama. "Real-time mandibular movement analysis system using four-dimensional cranial bone model." Systems and Computers in Japan 37, no. 8 (2006): 1–12. http://dx.doi.org/10.1002/scj.20582.
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Moazen, Mehran, Neil Curtis, Paul O'Higgins, Marc E. H. Jones, Susan E. Evans, and Michael J. Fagan. "Assessment of the role of sutures in a lizard skull: a computer modelling study." Proceedings of the Royal Society B: Biological Sciences 276, no. 1654 (September 2, 2008): 39–46. http://dx.doi.org/10.1098/rspb.2008.0863.
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Sutures form an integral part of the functioning skull, but their role has long been debated among vertebrate morphologists and palaeontologists. Furthermore, the relationship between typical skull sutures, and those involved in cranial kinesis, is poorly understood. In a series of computational modelling studies, complex loading conditions obtained through multibody dynamics analysis were imposed on a finite element model of the skull of Uromastyx hardwickii , an akinetic herbivorous lizard. A finite element analysis (FEA) of a skull with no sutures revealed higher patterns of strain in regions where cranial sutures are located in the skull. From these findings, FEAs were performed on skulls with sutures (individual and groups of sutures) to investigate their role and function more thoroughly. Our results showed that individual sutures relieved strain locally, but only at the expense of elevated strain in other regions of the skull. These findings provide an insight into the behaviour of sutures and show how they are adapted to work together to distribute strain around the skull. Premature fusion of one suture could therefore lead to increased abnormal loading on other regions of the skull causing irregular bone growth and deformities. This detailed investigation also revealed that the frontal–parietal suture of the Uromastyx skull played a substantial role in relieving strain compared with the other sutures. This raises questions about the original role of mesokinesis in squamate evolution.
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Bertocci, Gina E., Nathan P. Brown, and Patrice M. Mich. "Biomechanics of an orthosis-managed cranial cruciate ligament-deficient canine stifle joint predicted by use of a computer model." American Journal of Veterinary Research 78, no. 1 (January 2017): 27–35. http://dx.doi.org/10.2460/ajvr.78.1.27.
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Butler, Jeff, Burt Pryor, and Mary Grieder. "Impression Formation as a Function of Male Baldness." Perceptual and Motor Skills 86, no. 1 (February 1998): 347–50. http://dx.doi.org/10.2466/pms.1998.86.1.347.
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A computer-morphing procedure was used to produce a “full cranial hair” photograph for comparisons of perceptions by 96 undergraduates of a photograph of a naturally bald 30-yr.-old man on 13 dependent measures derived from 30 semantic differential scales. Analysis showed the full-hair condition was rated significantly more dominant, dynamic, and masculine than the bald condition. While the model was also perceived as younger in the full-hair condition, there was no difference in mean ratings of attractiveness between photographs.
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Oishi, Makoto, Masafumi Fukuda, Tetsuya Hiraishi, Naoki Yajima, Yosuke Sato, and Yukihiko Fujii. "Interactive virtual simulation using a 3D computer graphics model for microvascular decompression surgery." Journal of Neurosurgery 117, no. 3 (September 2012): 555–65. http://dx.doi.org/10.3171/2012.5.jns112334.
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Object The purpose of this paper is to report on the authors' advanced presurgical interactive virtual simulation technique using a 3D computer graphics model for microvascular decompression (MVD) surgery. Methods The authors performed interactive virtual simulation prior to surgery in 26 patients with trigeminal neuralgia or hemifacial spasm. The 3D computer graphics models for interactive virtual simulation were composed of the brainstem, cerebellum, cranial nerves, vessels, and skull individually created by the image analysis, including segmentation, surface rendering, and data fusion for data collected by 3-T MRI and 64-row multidetector CT systems. Interactive virtual simulation was performed by employing novel computer-aided design software with manipulation of a haptic device to imitate the surgical procedures of bone drilling and retraction of the cerebellum. The findings were compared with intraoperative findings. Results In all patients, interactive virtual simulation provided detailed and realistic surgical perspectives, of sufficient quality, representing the lateral suboccipital route. The causes of trigeminal neuralgia or hemifacial spasm determined by observing 3D computer graphics models were concordant with those identified intraoperatively in 25 (96%) of 26 patients, which was a significantly higher rate than the 73% concordance rate (concordance in 19 of 26 patients) obtained by review of 2D images only (p < 0.05). Surgeons evaluated interactive virtual simulation as having “prominent” utility for carrying out the entire surgical procedure in 50% of cases. It was evaluated as moderately useful or “supportive” in the other 50% of cases. There were no cases in which it was evaluated as having no utility. The utilities of interactive virtual simulation were associated with atypical or complex forms of neurovascular compression and structural restrictions in the surgical window. Finally, MVD procedures were performed as simulated in 23 (88%) of the 26 patients . Conclusions Our interactive virtual simulation using a 3D computer graphics model provided a realistic environment for performing virtual simulations prior to MVD surgery and enabled us to ascertain complex microsurgical anatomy.
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Skaropoulos, N. C., and D. P. Chrissoulidis. "DISTRIBUTION OF HEATING POTENTIAL IN AN ECCENTRIC SPHERES MODEL OF A CRANIAL STRUCTURE." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 14, no. 4 (April 1995): 279–82. http://dx.doi.org/10.1108/eb051957.
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Santos, Pedro O., Gustavo P. Carmo, Ricardo J. Alves de Sousa, Fábio A. O. Fernandes, and Mariusz Ptak. "Mechanical Strength Study of a Cranial Implant Using Computational Tools." Applied Sciences 12, no. 2 (January 15, 2022): 878. http://dx.doi.org/10.3390/app12020878.
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The human head is sometimes subjected to impact loads that lead to skull fracture or other injuries that require the removal of part of the skull, which is called craniectomy. Consequently, the removed portion is replaced using autologous bone or alloplastic material. The aim of this work is to develop a cranial implant to fulfil a defect created on the skull and then study its mechanical performance by integrating it on a human head finite element model. The material chosen for the implant was PEEK, a thermoplastic polymer that has been recently used in cranioplasty. A6 numerical model head coupled with an implant was subjected to analysis to evaluate two parameters: the number of fixation screws that enhance the performance and ensure the structural integrity of the implant, and the implant’s capacity to protect the brain compared to the integral skull. The main findings point to the fact that, among all tested configurations of screws, the model with eight screws presents better performance when considering the von Mises stress field and the displacement field on the interface between the implant and the skull. Additionally, under the specific analyzed conditions, it is observable that the model with the implant offers more efficient brain protection when compared with the model with the integral skull.
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McLennan, Rebecca, Caleb M. Bailey, Linus J. Schumacher, Jessica M. Teddy, Jason A. Morrison, Jennifer C. Kasemeier-Kulesa, Lauren A. Wolfe, et al. "DAN (NBL1) promotes collective neural crest migration by restraining uncontrolled invasion." Journal of Cell Biology 216, no. 10 (August 15, 2017): 3339–54. http://dx.doi.org/10.1083/jcb.201612169.
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Neural crest cells are both highly migratory and significant to vertebrate organogenesis. However, the signals that regulate neural crest cell migration remain unclear. In this study, we test the function of differential screening-selected gene aberrant in neuroblastoma (DAN), a bone morphogenetic protein (BMP) antagonist we detected by analysis of the chick cranial mesoderm. Our analysis shows that, before neural crest cell exit from the hindbrain, DAN is expressed in the mesoderm, and then it becomes absent along cell migratory pathways. Cranial neural crest and metastatic melanoma cells avoid DAN protein stripes in vitro. Addition of DAN reduces the speed of migrating cells in vivo and in vitro, respectively. In vivo loss of function of DAN results in enhanced neural crest cell migration by increasing speed and directionality. Computer model simulations support the hypothesis that DAN restrains cell migration by regulating cell speed. Collectively, our results identify DAN as a novel factor that inhibits uncontrolled neural crest and metastatic melanoma invasion and promotes collective migration in a manner consistent with the inhibition of BMP signaling.
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Rafael, P., B. Goin, P. Buttin, T. Cachon, and E. Viguier. "Comparison of two methods of fixation with interference screw for cranial cruciate ligament reconstruction in canine cadaver model." Computer Methods in Biomechanics and Biomedical Engineering 23, sup1 (October 19, 2020): S247—S249. http://dx.doi.org/10.1080/10255842.2020.1812846.
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Coelho, Giselle, Liana Beni Adami, and Nelci Zanon. "O papel da simulação na prática cirúrgica e a criação de uma nova ferramenta para treinamento neurocirúrgico." Scientia Medica 28, no. 1 (March 29, 2018): 29129. http://dx.doi.org/10.15448/1980-6108.2018.1.29129.
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AIMS: To test a new tool for neurosurgical education, a "puzzle" to simulate the craniosynostosis surgical correction (specifically scaphocephaly) using Renier’s "H" technique.METHODS: The cranial model was created by obtaining images through a multi slice (1 mm) CT scan in the Digital Imaging and Communications in Medicine (DICOM) format. This information was then processed using a computing algorithm to generate a three-dimensional biomodel in resine (performed on a computer or via computer simulation). The puzzle and its training possibilities were evaluated qualitatively by a team of expert neurosurgeons. Subsequently the experts evaluated the application of the tool for residents in neurosurgery, and the residents also evaluated the experience.RESULTS: Five experts neurosurgeons and 10 neurosurgery residents participated in the evaluation. All considered the tool positive for the proposed training. The experts have commented on how interesting the model may be by instigating the understanding of the reasons for each surgical step and how to act in them. According to the experts perceptions, the residents presented better clarity in the three-dimensional visualization of the step by step, indirectly aiding in the understanding of the surgical technique. In addition, they noted a notable reduction of errors with each attempt to assemble the puzzle. Residents considered it to be a teaching method that makes assessment objective and clear. Among the interviewers, 9,9 was the averaged note given to the simulator. CONCLUSIONS: The puzzle in cranial shape can be a complementary tool, allowing varying degrees of immersion and realism. It provides a notion of physical reality, offering symbolic, geometric and dynamic information, with rich tridimensional visualization. The simulator use may potentially improve and abbreviate the surgeons learning curve, in a safe manner.
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Palumbo, G., A. Piccininni, G. Ambrogio, and E. Sgambitterra. "Design of custom cranial prostheses combining manufacturing and drop test finite element simulations." International Journal of Advanced Manufacturing Technology 111, no. 5-6 (October 15, 2020): 1627–41. http://dx.doi.org/10.1007/s00170-020-06213-w.
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Abstract In this work, impact puncture tests (drop tests) have been used to both tune numerical models and correlate the performance of customised titanium cranial prostheses to the manufacturing process. In fact, experimental drop tests were carried out either on flat disk-shaped samples or on prototypes of titanium cranial prostheses (Ti-Gr5 and Ti-Gr23 were used) fabricated via two innovative sheet metal forming processes (the super plastic forming (SPF) and the single point incremental forming (SPIF)). Results from drop tests on flat disk-shaped samples were used to define the material behaviour of the two investigated alloys in the finite element (FE) model, whereas drop tests on cranial prostheses for validation purposes. Two different approaches were applied and compared for the FE simulation of the drop test: (i) assuming a constant thickness (equal to the one of the undeformed blank) or (ii) importing the thickness distribution determined by the sheet forming processes. The FE model of the drop test was used to numerically evaluate the effect of the manufacturing process parameters on the impact performance of the prostheses: SPF simulations were run changing the strain rate and the tool configuration, whereas SPIF simulations were run changing the initial thickness of the sheet and the forming strategy. The comparison between numerical and experimental data revealed that the performance in terms of impact response of the prostheses strongly depends on its thickness distribution, being strain hardening phenomena absent due to the working conditions adopted for the SPF process or to the annealing treatment conducted after the SPIF process. The manufacturing parameters/routes, able to affect the thickness distribution, can be thus effectively related to the mechanical performance of the prosthesis determined through impact puncture tests.
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Brown, Nathan P., Gina E. Bertocci, and Denis J. Marcellin-Little. "Influence of biomechanical parameters on cranial cruciate ligament–deficient or –intact canine stifle joints assessed by use of a computer simulation model." American Journal of Veterinary Research 76, no. 11 (November 2015): 952–58. http://dx.doi.org/10.2460/ajvr.76.11.952.
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Gökyar, Ahmet, and Cengiz Cokluk. "Localization of Intracranial Lesions Using Superficial Stereotaxic Cranial Lesion Locator Based on Magnetic Resonance Images." Surgical Innovation 26, no. 1 (March 30, 2018): 82–85. http://dx.doi.org/10.1177/1553350618764797.
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Background. Detection of a deep-seated lesion located in the brain parenchyma and major neuroanatomical sites is a critical issue in neurosurgery. Some neurosurgical cranial navigation systems have been developed that are available; however, some preparation is necessary, including the installation of complex computer software programs and obtaining specific neuroradiological images. Objective. The purpose of this experimental study was to design and evaluate a superficial stereotaxic frameless lesion locator in order to localize mass lesions within the brain. Methods. A superficial stereotaxic frameless lesion locator system was designed using cardboard and the Cartesian coordinate system as a reference framework. This material was used in a model creating printed magnetic resonance images in the superficially marking of the lesion. This material easily located the lesion placement and superficially projected the lesion location. Results. The results of this study revealed that the superficial stereotaxic frameless lesion location procedure using a coordinate cardboard locator is a safe, fast, and simple procedure. This procedure provides an accurate means of locating the target lesion seated within the brain parenchyma. When compared with other models, we found that this device is reliable and has a high rate of superficial lesion detection. Conclusion. A superficial lesion locator may be used in clinical practice. This experimental study demonstrated the usability and reliability of the procedure. Additional detailed investigations are necessary to improve the procedure.
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Böddeker, J., S. Drüen, A. Meyer-Lindenberg, M. Fehr, I. Nolte, and P. Wefstaedt. "Computer-assisted gait analysis of the dog: Comparison of two surgical techniques for the ruptured cranial cruciate ligament." Veterinary and Comparative Orthopaedics and Traumatology 25, no. 01 (2012): 11–21. http://dx.doi.org/10.3415/vcot-10-02-0025.
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SummaryObjectives: To compare the improvement in degree of lameness following surgical repair of cranial cruciate ligament rupture in dogs using computer-assisted gait analysis.Methods: Two groups of 14 dogs were used. One group was treated by a capsular-fascial imbrication method, and the other group by tibial plateau levelling osteotomy (TPLO). All dogs underwent gait analysis prior to surgery, as well as at four days, four weeks, and four months after surgery. Symmetry indices of vertical ground reaction forces as well as vertical ground reaction forces in % body weight, joint angles and certain gait cycle parameters were evaluated.Results: Four months after surgery, the degree of lameness expressed as symmetry index for peak vertical force for the TPLO group (5.83%) was not significantly different to the capsular-fascial imbrication group (19.05%). Within the TPLO group, there was a significantly increased ability to extend the stifle joint four months after surgery. The stifle motion pattern of the capsular-fascial imbrication group as well as the range-of-motion in both groups showed very little change at the time of the last gait analysis. The complication rate was greater in the TPLO group than in the capsular-fascial group.Clinical significance: In conclusion the results suggest that the TPLO method leads to a faster recovery and improved limb function in comparison to the capsular-fascial imbrication method four months after surgery. Further analyses are needed to determine if the TPLO method is superior concerning long-term joint stability.Online supplementary material: A video of the three-dimensional kinematic model is available online at: http://www.vcot-online.com
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Moiduddin, Khaja, Syed Hammad Mian, Usama Umer, and Hisham Alkhalefah. "Fabrication and Analysis of a Ti6Al4V Implant for Cranial Restoration." Applied Sciences 9, no. 12 (June 20, 2019): 2513. http://dx.doi.org/10.3390/app9122513.
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A custom made implant is critical in cranioplasty to cushion and restore intracranial anatomy, as well as to recover the appearance and attain cognitive stability in the patient. The utilization of customized titanium alloy implants using three-dimensional (3D) reconstruction technique and fabricated using Electron Beam Melting (EBM) has gained significant recognition in recent years, owing to their convenience and effectiveness. Besides, the conventional technique or the extant practice of transforming the standard plates is unreliable, arduous and tedious. As a result, this work aims to produce a customized cranial implant using 3D reconstruction that is reliable in terms of fitting accuracy, appearance, mechanical strength, and consistent material composition. A well-defined methodology initiating from EBM fabrication to final validation has been outlined in this work. The custom design of the implant was carried out by mirror reconstruction of the skull’s defective region, acquired through computer tomography. The design of the customized implant was then analyzed for mechanical stresses by applying finite element analysis. Consequently, the 3D model of the implant was fabricated from Ti6Al4V ELI powder with a thickness of ≃1.76–2 mm. Different tests were employed to evaluate the bio-mechanical stability and strength of the fabricated customized implant design. A 3D comparison study was performed to ensure there was anatomical accuracy, as well as to maintain gratifying aesthetics. The bio-mechanical analysis results revealed that the maximum Von Mises stress (2.5 MPa), strain distribution (1.49 × 10−4) and deformation (3.26 × 10−6 mm) were significantly low in magnitude, thus proving the implant load resistance ability. The average yield and tensile strengths for the fabricated Ti6Al4V ELI EBM specimen were found to be 825 MPa and 880 MPa, respectively, which were well over the prescribed strength for Ti6Al4V ELI implant material. The hardness study also resulted in an acceptable outcome within the acceptable range of 30–35 HRC. Certainly, the chemical composition of the fabricated EBM specimen was intact as established in EDX analysis. The weight of the cranial implant (128 grams) was also in agreement with substituted defected bone portion, ruling out any stress shielding effect. With the proposed approach, the anatomy of the cranium deformities can be retrieved effectively and efficiently. The implementation of 3D reconstruction techniques can conveniently reduce tedious alterations in the implant design and subsequent errors. It can be a valuable and reliable approach to enhance implant fitting, stability, and strength.
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Brown, Nathan P., Gina E. Bertocci, and Denis J. Marcellin-Little. "Evaluation of varying morphological parameters on the biomechanics of a cranial cruciate ligament–deficient or intact canine stifle joint with a computer simulation model." American Journal of Veterinary Research 75, no. 1 (January 2014): 26–33. http://dx.doi.org/10.2460/ajvr.75.1.26.
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Jägersberg, Max, Michael Kosterhon, and Florian Ringel. "Caliper navigation for craniotomy planning of convexity targets." PLOS ONE 16, no. 5 (May 20, 2021): e0251023. http://dx.doi.org/10.1371/journal.pone.0251023.
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Introduction A technique to localize a radiological target on the head convexity fast and with acceptable precision is sufficient for surgeries of superficial intracranial lesions, and of help in the setting of emergency surgery, computer navigation breakdown, limited resources and education. We present a caliper technique based on fundamental geometry, with inexpensive and globally available tools (conventional CT or MRI image viewer, calculator, caliper). Methods The distances of the radiological target from two landmarks (nasion and porus acusticus externus) are assessed with an image viewer and Pythagoras’ theorem. The two distances are then marked around the landmarks onto the head of the patient with help of a caliper. The intersection defines the target. We tested the technique in a saw bone skull model and afterwards in the operating room. Convexity targets were localized with the caliper navigation technique and then with computer navigation as ground truth. Results In the saw bone model, the mean offset between the caliper navigated target and the real target was 2.9 ± 2.8 mm, 95% CI (1.6 mm; 4.2 mm). The mean offset between computer navigated target and real target was 1.6 ± 0.9 mm, 95% CI (1.2 mm; 2 mm) (ns). In 15 patients undergoing navigated cranial procedures, 100 targets were assessed in reference to computer navigation. The mean offset of the caliper navigation was 11 ± 5.2 mm, 95% CI (9.9 mm; 12 mm). Conclusion This is a low-tech approach for translation of a radiological target to the patient’s head in short time and with globally available inexpensive tools, with satisfying precision for many procedures.
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Yang, Rui, Haoran Zuo, Shusheng Han, Xiaoping Zhang, and Qian Zhang. "Computer-Aided Diagnosis of Children with Cerebral Palsy under Deep Learning Convolutional Neural Network Image Segmentation Model Combined with Three-Dimensional Cranial Magnetic Resonance Imaging." Journal of Healthcare Engineering 2021 (November 10, 2021): 1–11. http://dx.doi.org/10.1155/2021/1822776.
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In this paper, we analyzed the application value and effect of deep learn-based image segmentation model of convolutional neural network (CNN) algorithm combined with 3D brain magnetic resonance imaging (MRI) in diagnosis of cerebral palsy in children. 3D brain model was segmented based on CNN algorithm to obtain the segmented MRI images of brain tissue, and the validity was verified. Then, 70 children with cerebral palsy were rolled into the observation group (n = 35), which received MRI for diagnosis after segmentation of brain tissue, and control group (n = 35), which were diagnosed by computed tomography (CT). The diagnosis results of the two groups were compared. The validity experiment verified that the image segmentation method based on CNN algorithm can obtain effective style graphics. In clinical trials, the diagnostic accuracy of 88.6% in the observation group was evidently superior to that of 80% in the control group ( P < 0.05 ). In the observation group, one patient was diagnosed as normal, four patients had white matter lesions, 17 patients had corpus callosum lesions, and five patients had basal ganglia softening foci. In the control group, two patients were diagnosed as normal, two patients had white matter lesions, 19 patients had corpus callosum lesions, and four patients had basal ganglia softening foci. No notable difference was found between the two groups ( P > 0.05 ). According to the research results, in the diagnosis of cerebral palsy in children, the image segmentation of brain 3D model based on CNN to obtain the MRI image of segmented brain tissue can effectively improve the detection accuracy. Moreover, the specific symptoms can be diagnosed clearly. It can provide the corresponding diagnostic basis for clinical diagnosis and treatment and was worthy of clinical promotion.
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Nettleton, Karissa, Derek Luong, Alex P. Kleinfehn, Laura Savariau, Christopher Premanandan, and Matthew L. Becker. "Molecular Mass‐Dependent Resorption and Bone Regeneration of 3D Printed PPF Scaffolds in a Critical‐Sized Rat Cranial Defect Model." Advanced Healthcare Materials 8, no. 17 (July 22, 2019): 1900646. http://dx.doi.org/10.1002/adhm.201900646.
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Li, Zhigang, Cheng Ji, and Lishu Wang. "Development of a child head analytical dynamic model considering cranial nonuniform thickness and curvature – Applying to children aged 0–1 years old." Computer Methods and Programs in Biomedicine 161 (July 2018): 181–89. http://dx.doi.org/10.1016/j.cmpb.2018.04.022.
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Nagasao, Tomohisa, Junpei Miyamoto, Yumiko Uchikawa, Tamotsu Tamaki, Akira Yamada, Tsuyoshi Kaneko, Hua Jiang, and Yasushige Issiki. "A Biomechanical Study on the Effect of Premature Fusion of the Frontosphenoidal Suture on Orbit Asymmetry in Unilateral Coronal Synostosis." Cleft Palate-Craniofacial Journal 47, no. 1 (January 2010): 82–91. http://dx.doi.org/10.1597/08-164.1.
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Objective The coronal ring of patients with unilateral coronal synostosis (UCS) presents premature fusion. This study aims to elucidate whether or not the dynamic behavior of the orbit in response to intracranial pressure (ICP) differs between patients in whom the premature fusion exists only in the frontoparietal suture (FPS) and those in whom the premature fusion extends to the frontosphenoidal suture (FSS). Methods A total of 15 UCS patients were included in the present study. Patients in whom premature fusion was seen inside the FPS and those in whom premature fusion extended to the FSS were categorized as FP Only (4.2 ± 1.4 m/o) and FP + FS groups (4.6 ± 2.2 m/o), respectively. On the basis of computed tomography (CT) data, computer-aided design models were produced. Pressure of 15 mm Hg was applied to the neurocranium of each skull model to simulate ICP. Using the finite element method, the displacements presented by each model's orbits were calculated. Displacements of the two groups were compared. Results The orbit demonstrated greater displacement in the FP Only group than in the FP + FS group, suggesting that premature closure of the FSS disturbs growth of the orbit in response to ICP. Conclusion In performing surgical treatment for UCS, the degree of fusion that the FSS presents should be evaluated carefully. In cases in which the FSS presents premature fusion, it is recommended to release the fusion at an early stage of cranial growth to improve the appearance of the orbital region.
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Mian, Syed Hammad, Khaja Moiduddin, Sherif Mohammed Elseufy, and Hisham Alkhalefah. "Adaptive Mechanism for Designing a Personalized Cranial Implant and Its 3D Printing Using PEEK." Polymers 14, no. 6 (March 21, 2022): 1266. http://dx.doi.org/10.3390/polym14061266.
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The rehabilitation of the skull’s bones is a difficult process that poses a challenge to the surgical team. Due to the range of design methods and the availability of materials, the main concerns are the implant design and material selection. Mirror-image reconstruction is one of the widely used implant reconstruction techniques, but it is not a feasible option in asymmetrical regions. The ideal design approach and material should result in an implant outcome that is compact, easy to fit, resilient, and provides the perfect aesthetic and functional outcomes irrespective of the location. The design technique for the making of the personalized implant must be easy to use and independent of the defect’s position on the skull. As a result, this article proposes a hybrid system that incorporates computer tomography acquisition, an adaptive design (or modeling) scheme, computational analysis, and accuracy assessment. The newly developed hybrid approach aims to obtain ideal cranial implants that are unique to each patient and defect. Polyetheretherketone (PEEK) is chosen to fabricate the implant because it is a viable alternative to titanium implants for personalized implants, and because it is simpler to use, lighter, and sturdy enough to shield the brain. The aesthetic result or the fitting accuracy is adequate, with a maximum deviation of 0.59 mm in the outside direction. The results of the biomechanical analysis demonstrate that the maximum Von Mises stress (8.15 MPa), Von Mises strain (0.002), and deformation (0.18 mm) are all extremely low, and the factor of safety is reasonably high, highlighting the implant’s load resistance potential and safety under high loading. Moreover, the time it takes to develop an implant model for any cranial defect using the proposed modeling scheme is very fast, at around one hour. This study illustrates that the utilized 3D reconstruction method and PEEK material would minimize time-consuming alterations while also improving the implant’s fit, stability, and strength.
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Kosterhon, Michael, Angelika Gutenberg, Sven Rainer Kantelhardt, Elefterios Archavlis, and Alf Giese. "Navigation and Image Injection for Control of Bone Removal and Osteotomy Planes in Spine Surgery." Operative Neurosurgery 13, no. 2 (January 2, 2017): 297–304. http://dx.doi.org/10.1093/ons/opw017.
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Abstract BACKGROUND AND IMPORTANCE: In contrast to cranial interventions, neuronavigation in spinal surgery is used in few applications, not tapping into its full technological potential. We have developed a method to preoperatively create virtual resection planes and volumes for spinal osteotomies and export 3-D operation plans to a navigation system controlling intraoperative visualization using a surgical microscope's head-up display. The method was developed using a Sawbone® model of the lumbar spine, demonstrating feasibility with high precision. Computer tomographic and magnetic resonance image data were imported into Amira®, a 3-D visualization software. Resection planes were positioned, and resection volumes representing intraoperative bone removal were defined. Fused to the original Digital Imaging and Communications in Medicine data, the osteotomy planes were exported to the cranial version of a Brainlab® navigation system. A navigated surgical microscope with video connection to the navigation system allowed intraoperative image injection to visualize the preplanned resection planes. CLINICAL PRESENTATION: The workflow was applied to a patient presenting with a congenital hemivertebra of the thoracolumbar spine. Dorsal instrumentation with pedicle screws and rods was followed by resection of the deformed vertebra guided by the in-view image injection of the preplanned resection planes into the optical path of a surgical microscope. Postoperatively, the patient showed no neurological deficits, and the spine was found to be restored in near physiological posture. CONCLUSION: The intraoperative visualization of resection planes in a microscope's head-up display was found to assist the surgeon during the resection of a complex-shaped bone wedge and may help to further increase accuracy and patient safety.
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Marsalek, Pavel, Martin Sotola, David Rybansky, Vojtech Repa, Radim Halama, Martin Fusek, and Jiri Prokop. "Modeling and Testing of Flexible Structures with Selected Planar Patterns Used in Biomedical Applications." Materials 14, no. 1 (December 30, 2020): 140. http://dx.doi.org/10.3390/ma14010140.
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Flexible structures (FS) are thin shells with a pattern of holes. The stiffness of the structure in the normal direction is reduced by the shape of gaps rather than by the choice of the material based on mechanical properties such as Young’s modulus. This paper presents virtual prototyping of 3D printed flexible structures with selected planar patterns using laboratory testing and computer modeling. The objective of this work is to develop a non-linear computational model evaluating the structure’s stiffness and its experimental verification; in addition, we aimed to identify the best of the proposed patterns with respect to its stiffness: load-bearing capacity ratio. Following validation, the validated computational model is used for a parametric study of selected patterns. Nylon—Polyamide 12—was chosen for the purposes of this study as an appropriate flexible material suitable for 3D printing. At the end of the work, a computational model of the selected structure with modeling of load-bearing capacity is presented. The obtained results can be used in the design of external biomedical applications such as orthoses, prostheses, cranial remoulding helmets padding, or a new type of adaptive cushions. This paper is an extension of the conference paper: “Modeling and Testing of 3D Printed Flexible Structures with Three-pointed Star Pattern Used in Biomedical Applications” by authors Repa et al.
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Cotti, Silvia, Ann Huysseune, Wolfgang Koppe, Martin Rücklin, Federica Marone, Eva M. Wölfel, Imke A. K. Fiedler, Björn Busse, Antonella Forlino, and P. Eckhard Witten. "More Bone with Less Minerals? The Effects of Dietary Phosphorus on the Post-Cranial Skeleton in Zebrafish." International Journal of Molecular Sciences 21, no. 15 (July 30, 2020): 5429. http://dx.doi.org/10.3390/ijms21155429.
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Dietary phosphorus (P) is essential for bone mineralisation in vertebrates. P deficiency can cause growth retardation, osteomalacia and bone deformities, both in teleosts and in mammals. Conversely, excess P supply can trigger soft tissue calcification and bone hypermineralisation. This study uses a wide range of complementary techniques (X-rays, histology, TEM, synchrotron X-ray tomographic microscopy, nanoindentation) to describe in detail the effects of dietary P on the zebrafish skeleton, after two months of administering three different diets: 0.5% (low P, LP), 1.0% (regular P, RP), and 1.5% (high P, HP) total P content. LP zebrafish display growth retardation and hypomineralised bones, albeit without deformities. LP zebrafish increase production of non-mineralised bone matrix, and osteoblasts have enlarged endoplasmic reticulum cisternae, indicative for increased collagen synthesis. The HP diet promotes growth, high mineralisation, and stiffness but causes vertebral centra fusions. Structure and arrangement of bone matrix collagen fibres are not influenced by dietary P in all three groups. In conclusion, low dietary P content stimulates the formation of non-mineralised bone without inducing malformations. This indicates that bone formation and mineralisation are uncoupled. In contrast, high dietary P content promotes mineralisation and vertebral body fusions. This new zebrafish model is a useful tool to understand the mechanisms underlying osteomalacia and abnormal mineralisation, due to underlying variations in dietary P levels.
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Bickle, Ian C. "3D Stereolithographic Modeling of Inverted Papilloma." Philippine Journal of Otolaryngology-Head and Neck Surgery 30, no. 1 (June 30, 2015): 67–68. http://dx.doi.org/10.32412/pjohns.v30i1.401.
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This middle-aged woman presented for the first time to ENT clinic with a complaint of nasal stuffiness.
Computed Tomography (CT) of the paranasal sinuses was performed following clinical review that revealed a left intranasal mass.
Due to a radiological suspicion of an inverted papilloma, Magnetic Resonance Imaging (MRI) of the paranasal sinuses was performed.
This, combined with endoscopic biopsy confirmed an inverted papilloma.
Following referral to oral maxillofacial surgery (OMF), 3D modelling was performed using the original CT data to aid surgical planning.
DISCUSSION
Dramatic technological advancements in the fields of medical imaging and computer aided design (CAD) in the past decade have enabled sterolithographic 3D modelling to evolve from a research aspiration to everyday reality.
The widespread availability of high-resolution volumetric data sets, providing isotropic imaging from cross-sectional imaging studies allows for exquisite 3D model production using rapid prototyping techniques.1
Although its domains are ever widening, its use is most established in the fields of oral maxillofacial (OMF) surgery and otolaryngology enabling surgical planning in anatomically complex areas which often require lengthy and complex surgery.2 Similarly, in these fields the 3D modelling assists in prosthesis design and production, with additional professional advantages, such as teaching aids and aiding patient consent.
In this illustrative case a mass occupies the left ethmoidal and frontal sinuses with destruction of the floor of the anterior cranial fossa (Figure 1 A,B) with further delineation on MRI (Figure 2 A,B). This case of an inverted papilloma illustrates the tremendous assistance that 3D modelling offers to the surgeon in examining the anatomical extent of the tumor, visualising their surgical approach and planning the operative procedure. (Figure 3) For example, in this case a combined procedure between the OMF and the neurosurgery departments was undertaken with a bifrontal craniotomy and maxillectomy. Operating times have also been shown to improve following the use of 3D models as preparation prior to surgery is more robust.3
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Csernyava, Olivér, Bálint Péter Horváth, Zsolt Badics, and Sándor Bilicz. "Fast and numerically stable Mie solution of EM near field and absorption for stratified spheres." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 41, no. 3 (January 5, 2022): 1011–23. http://dx.doi.org/10.1108/compel-03-2021-0081.
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Purpose The purpose of this paper is the development of an analytic computational model for electromagnetic (EM) wave scattering from spherical objects. The main application field is the modeling of electrically large objects, where the standard numerical techniques require huge computational resources. An example is full-wave modeling of the human head in the millimeter-wave regime. Hence, an approximate model or analytical approach is used. Design/methodology/approach The Mie–Debye theorem is used for calculating the EM scattering from a layered dielectric sphere. The evaluation of the analytical expressions involved in the infinite sum has several numerical instabilities, which makes the precise calculation a challenge. The model is validated through an application example with comparing results to numerical calculations (finite element method). The human head model is used with the approximation of a two-layer sphere, where the brain tissues and the cranial bones are represented by homogeneous materials. Findings A significant improvement is introduced for the stable calculation of the Mie coefficients of a core–shell stratified sphere illuminated by a linearly polarized EM plane wave. Using this technique, a semi-analytical expression is derived for the power loss in the sphere resulting in quick and accurate calculations. Originality/value Two methods are introduced in this work with the main objective of estimating the final precision of the results. This is an important aspect for potentially unstable calculations, and the existing implementations have not included this feature so far.
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Walther, Georg, Christian Martin, Amelie Haase, Ulf Nestler, and Stefan Schob. "Machine Learning for Rupture Risk Prediction of Intracranial Aneurysms: Challenging the PHASES Score in Geographically Constrained Areas." Symmetry 14, no. 5 (May 5, 2022): 943. http://dx.doi.org/10.3390/sym14050943.
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Intracranial aneurysms represent a potentially life-threatening condition and occur in 3–5% of the population. They are increasingly diagnosed due to the broad application of cranial magnetic resonance imaging and computed tomography in the context of headaches, vertigo, and other unspecific symptoms. For each affected individual, it is utterly important to estimate the rupture risk of the respective aneurysm. However, clinically applied decision tools, such as the PHASES score, remain insufficient. Therefore, a machine learning approach assessing the rupture risk of intracranial aneurysms is proposed in our study. For training and evaluation of the algorithm, data from a single neurovascular center was used, comprising 446 aneurysms (221 ruptured, 225 unruptured). The machine learning model was then compared with the PHASES score and proved superior in accuracy (0.7825), F1-score (0.7975), sensitivity (0.8643), specificity (0.7022), positive predictive value (0.7403), negative predictive value (0.8404), and area under the curve (0.8639). The frequency distributions of the predicted rupture probabilities and the PHASES score were analyzed. A symmetry can be observed between the rupture probabilities, with a symmetry axis at 0.5. A feature importance analysis reveals that the body mass index, consumption of anticoagulants, and harboring vessel are regarded as the most important features when assessing the rupture risk. On the other hand, the size of the aneurysm, which is weighted most in the PHASES score, is regarded as less important. Based on our findings we discuss the potential role of the model for clinical practice in geographically confined aneurysm patients.
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Bayerl, Simon H., Adnan Ghori, Melina Nieminen-Kelhä, Tiziana Adage, Jörg Breitenbach, Peter Vajkoczy, and Vincent Prinz. "In vitro and in vivo testing of a novel local nicardipine delivery system to the brain: a preclinical study." Journal of Neurosurgery 132, no. 2 (February 2020): 465–72. http://dx.doi.org/10.3171/2018.9.jns173085.
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OBJECTIVEThe management of patients with aneurysmal subarachnoid hemorrhage (aSAH) remains a highly demanding challenge in critical care medicine. Despite all efforts, the calcium channel antagonist nimodipine remains the only drug approved for improving outcomes after aSAH. However, in its current form of application, it provides less than optimal efficacy and causes dose-limiting hypotension in a substantial number of patients. Here, the authors tested in vitro the release dynamics of a novel formulation of the calcium channel blocker nicardipine and in vivo local tolerance and tissue reaction using a chronic cranial window model in mice.METHODSTo characterize the release kinetics in vitro, dissolution experiments were performed using artificial cerebrospinal fluid over a time period of 21 days. The excipients used in this formulation (NicaPlant) for sustained nicardipine release are a mixture of two completely degradable polymers. A chronic cranial window in C57BL/6 mice was prepared, and NicaPlant slices were placed in proximity to the exposed cerebral vasculature. Epifluorescence video microscopy was performed right after implantation and on days 3 and 7 after surgery. Vessel diameter of the arteries and veins, vessel permeability, vessel configuration, and leukocyte–endothelial cell interaction were quantified by computer-assisted analysis. Immunofluorescence staining was performed to analyze inflammatory reactions and neuronal alterations.RESULTSIn vitro the nicardipine release profile showed an almost linear curve with about 80% release at day 15 and full release at day 21. In vivo epifluorescence video microscopy showed a significantly higher arterial vessel diameter in the NicaPlant group due to vessel dilatation (21.6 ± 2.6 µm vs 17.8 ± 1.5 µm in controls, p < 0.01) confirming vasoactivity of the implant, whereas the venous diameter was not affected. Vessel dilatation did not have any influence on the vessel permeability measured by contrast extravasation of the fluorescent dye in epifluorescence microscopy. Further, an increased leukocyte–endothelial cell interaction due to the implant could not be detected. Histological analysis did not show any microglial activation or accumulation. No structural neuronal changes were observed.CONCLUSIONSNicaPlant provides continuous in vitro release of nicardipine over a 3-week observation period. In vivo testing confirmed vasoactivity and lack of toxicity. The local application of this novel nicardipine delivery system to the subarachnoid space is a promising tool to improve patient outcomes while avoiding systemic side effects.
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Monteith, Stephen J., Ricky Medel, Neal F. Kassell, Max Wintermark, Matthew Eames, John Snell, Eyal Zadicario, Javier Grinfeld, Jason P. Sheehan, and W. Jeff Elias. "Transcranial magnetic resonance–guided focused ultrasound surgery for trigeminal neuralgia: a cadaveric and laboratory feasibility study." Journal of Neurosurgery 118, no. 2 (February 2013): 319–28. http://dx.doi.org/10.3171/2012.10.jns12186.
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Object Transcranial MR-guided focused ultrasound surgery (MRgFUS) is evolving as a treatment modality in neurosurgery. Until now, the trigeminal nerve was believed to be beyond the treatment envelope of existing high-frequency transcranial MRgFUS systems. In this study, the authors explore the feasibility of targeting the trigeminal nerve in a cadaveric model with temperature assessments using computer simulations and an in vitro skull phantom model fitted with thermocouples. Methods Six trigeminal nerves from 4 unpreserved cadavers were targeted in the first experiment. Preprocedural CT scanning of the head was performed to allow for a skull correction algorithm. Three-Tesla, volumetric, FIESTA MRI sequences were performed to delineate the trigeminal nerve and any vascular structures of the cisternal segment. The cadaver was positioned in a focused ultrasound transducer (650-kHz system, ExAblate Neuro, InSightec) so that the focus of the transducer was centered at the proximal trigeminal nerve, allowing for targeting of the root entry zone (REZ) and the cisternal segment. Real-time, 2D thermometry was performed during the 10- to 30-second sonication procedures. Post hoc MR thermometry was performed on a computer workstation at the conclusion of the procedure to analyze temperature effects at neuroanatomical areas of interest. Finally, the region of the trigeminal nerve was targeted in a gel phantom encased within a human cranium, and temperature changes in regions of interest in the skull base were measured using thermocouples. Results The trigeminal nerves were clearly identified in all cadavers for accurate targeting. Sequential sonications of 25–1500 W for 10–30 seconds were successfully performed along the length of the trigeminal nerve starting at the REZ. Real-time MR thermometry confirmed the temperature increase as a narrow focus of heating by a mean of 10°C. Postprocedural thermometry calculations and thermocouple experiments in a phantom skull were performed and confirmed minimal heating of adjacent structures including the skull base, cranial nerves, and cerebral vessels. For targeting, inclusion of no-pass regions through the petrous bone decreased collateral heating in the internal acoustic canal from 16.7°C without blocking to 5.7°C with blocking. Temperature at the REZ target decreased by 3.7°C with blocking. Similarly, for midcisternal targeting, collateral heating at the internal acoustic canal was improved from a 16.3°C increase to a 4.9°C increase. Blocking decreased the target temperature increase by 4.4°C for the same power settings. Conclusions This study demonstrates focal heating of up to 18°C in a cadaveric trigeminal nerve at the REZ and along the cisternal segment with transcranial MRgFUS. Significant heating of the skull base and surrounding neural structures did not occur with implementation of no-pass regions. However, in vivo studies are necessary to confirm the safety and efficacy of this potentially new, noninvasive treatment.
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Hackett, J. T., S. L. Cochran, L. J. Greenfield, D. C. Brosius, and T. Ueda. "Synapsin I injected presynaptically into goldfish mauthner axons reduces quantal synaptic transmission." Journal of Neurophysiology 63, no. 4 (April 1, 1990): 701–6. http://dx.doi.org/10.1152/jn.1990.63.4.701.
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1. Synapsin I was injected into a vertebrate presynaptic axon to analyze its action on quantal synaptic transmission. Two microelectrodes were used for simultaneous intracellular recording from pairs of identified neurons in the goldfish brain. The postsynaptic electrode was placed in a cranial relay neuron (CRN) within 100 microns of its synapse with the Mauthner neuron. The presynaptic electrode impaled the Mauthner axon (M-axon) 50-200 microns from the first electrode. 2. Spontaneous miniature excitatory postsynaptic potentials (mEPSPs) and evoked postsynaptic potentials (EPSPs) were recorded at steady states before and after synapsin I was microinjected into the presynaptic M-axon. Responses were digitized and subsequently analyzed by computer for quantal parameters. 3. In 12 experiments, injection of synapsin I resulted in a reduction in transmission. The decrease in EPSP amplitude began approximately 30 s after the injection, reached a plateau within 10 min, and appeared to be reversible and dose dependent. 4. Injection of synapsin I decreased quantal content (m), with no effect on postsynaptic receptor sensitivity or on amount of transmitter per quantum. Further analysis based on the simplest binomial model for quantal release revealed that synapsin I consistently reduced the number of quantal units available for release (n) although the probability of release (p) was either unchanged or slightly increased. Injected synapsin I may thus bind to presynaptic vesicles and prevent transmitter quanta from entering a pool subject to evoked release.
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Chen, Ya Dong, Hu Li, Wen Zheng Wu, and Wan Shan Wang. "Rapid Prototyping for Treatment of Cranial Reconstruction Surgery." Advanced Materials Research 415-417 (December 2011): 433–37. http://dx.doi.org/10.4028/www.scientific.net/amr.415-417.433.
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Design methods for medical rapid prototyping (RP) of personalized cranioplasty implants are presented in this paper. RP offers an easier way to design customized implants and manufacture them within a very short period. Computed tomography (CT) scans were acquired on a General Electric CT scanner and converted to solid models using Mimics software from Materialise. Stereo lithography patterns were prototyped using Objet build style on a Eden 250.The models helped the surgeons plan and rehearse the surgery well in advance. RP biomedical model is greatly convenient to diagnosis and treatment planning. It could decrease the operation time and the risk of misinterpretation of the medical problem. A physical biomedical model also facilitates surgery planning and makes the rehearsal and simulation of the operation possibly.
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Zwirner, Johann, Mario Scholze, Benjamin Ondruschka, and Niels Hammer. "What Is Considered a Variation of Biomechanical Parameters in Tensile Tests of Collagen-Rich Human Soft Tissues?—Critical Considerations Using the Human Cranial Dura Mater as a Representative Morpho-Mechanic Model." Medicina 56, no. 10 (October 5, 2020): 520. http://dx.doi.org/10.3390/medicina56100520.
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Background and Objectives: Profound knowledge on the load-dependent behavior of human soft tissues is required for the development of suitable replacements as well as for realistic computer simulations. Regarding the former, e.g., the anisotropy of a particular biological tissue has to be represented with site- and direction-dependent particular mechanical values. Contrary to this concept of consistent mechanical properties of a defined soft tissue, mechanical parameters of soft tissues scatter considerably when being determined in tensile tests. In spite of numerous measures taken to standardize the mechanical testing of soft tissues, several setup- and tissue-related factors remain to influence the mechanical parameters of human soft tissues to a yet unknown extent. It is to date unclear if measurement extremes should be considered a variation or whether these data have to be deemed incorrect measurement outliers. This given study aimed to determine mechanical parameters of the human cranial dura mater as a model for human soft tissues using a highly standardized protocol and based on this, critically evaluate the definition for the term mechanical “variation” of human soft tissue. Materials and Methods: A total of 124 human dura mater samples with an age range of 3 weeks to 94 years were uniformly retrieved, osmotically adapted and mechanically tested using customized 3D-printed equipment in a quasi-static tensile testing setup. Scanning electron microscopy of 14 samples was conducted to relate the mechanical parameters to morphological features of the dura mater. Results: The here obtained mechanical parameters were scattered (elastic modulus = 46.06 MPa, interquartile range = 33.78 MPa; ultimate tensile strength = 5.56 MPa, interquartile range = 4.09 MPa; strain at maximum force = 16.58%, interquartile range = 4.81%). Scanning electron microscopy revealed a multi-layered nature of the dura mater with varying fiber directions between its outer and inner surface. Conclusions: It is concluded that mechanical parameters of soft tissues such as human dura mater are highly variable even if a highly standardized testing setup is involved. The tissue structure and composition appeared to be the main contributor to the scatter of the mechanical parameters. In consequence, mechanical variation of soft tissues can be defined as the extremes of a biomechanical parameter due to an uncontrollable change in tissue structure and/or the respective testing setup.
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Ahmed, Sherif G., Casey A. Maguire, Shiliang Alice Cao, and Gary J. Brenner. "Schwannoma Gene Therapy via Adeno-Associated Viral Vector Delivery of Apoptosis-Associated Speck-like Protein Containing CARD (ASC): Preclinical Efficacy and Safety." International Journal of Molecular Sciences 23, no. 2 (January 13, 2022): 819. http://dx.doi.org/10.3390/ijms23020819.
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Schwannomas are tumors derived from Schwann-lineage cells, cells that protect and support myelinated nerves in the peripheral nervous system. They are typically slow-growing, encapsulated and benign. These tumors develop along peripheral, spinal and cranial nerves causing pain, sensory-motor dysfunction and death. Primary treatment for schwannoma is operative resection which can be associated with significant morbidity. Pharmacotherapy is largely restricted to bevacizumab, which has minimal or no efficacy for many patients and can be associated with treatment-limiting adverse effects. Given the suffering and morbidity associated with schwannoma and the paucity of therapeutic options, there is an urgent need for safe and effective therapies for schwannomas. We previously demonstrated that adeno-associated virus serotype 1 (AAV1) vector mediated delivery of the inflammasome adaptor protein, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) under the control of the P0 promoter, produced a prolonged reduction in tumor volume and tumor-associated pain in human xenograft and mouse syngeneic schwannoma models. Here, we present data essential for the translation of our AAV1-P0-ASC schwannoma gene therapy to clinical trials. We determine the minimum effective dose of AAV1-P0-hASC required to induce an anti-tumor effect in the xenograft human-schwannoma model. We also show that the presence of preexisting AAV1 immunity does not alter the antitumor efficacy of AAV-P0-mASC in a syngeneic mouse schwannoma model. Furthermore, the maximum deliverable intratumoral dose of AAV1-P0-ASC was not associated with neuronal toxicity in immunocompetent mice. Taken together, these safety and efficacy data support the translation of the AAV1-P0-ASC schwannoma gene therapy strategy to clinical trials.
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Yamada, Akira, Keisuke Imai, Takeru Nomachi, Takuya Fujimoto, Hiroaki Sakamoto, and Syohei Kitano. "Cranial Distraction for Plagiocephaly: Quantitative Morphologic Analyses of Cranium Using Three-Dimensional Computed Tomography and a Life-Size Model." Journal of Craniofacial Surgery 16, no. 4 (July 2005): 688–93. http://dx.doi.org/10.1097/01.scs.0000168995.27882.66.
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