OBJECTIVE: Graft failure is a common complication of cranioplasty.Revision cranioplasty is required to overcome this complication. However, no previous studies have reported outcomes in revision cranioplasty with three-dimensional (3D) custom-made titanium implants. We described our experience with 3D titanium implants in patients with revision cranioplasty.
METHODS: We evaluated 43 consecutive patients who underwent revision cranioplasty using 3D custom-made titanium implants between January 2011 and December 2019.The 3D image of the patient\'s cranium and the plan to close the cranium defect were created in a virtual environment using software programs. Demographic and radiological features were compared based on the materials used in the initial cranioplasty.
RESULTS: Previous material was autologous graft (AG) in 27 patients and polymethyl methacrylate (PMMA) in 16 patients. The mean time without revision cranioplasty is longer in patients with PMMA implants than in patients with AG. There was no statistically significant difference in the length of hospital stay between patients with PMMA implants and patients with AG. There were no postoperative adverse events such as infection, wound dehiscence, convulsions, and epidural hematoma in 38 patients during hospitalization. Wound dehiscence developedin 5 patients and surgical repair was required in one.
CONCLUSIONS: Initial cranioplasty with PMMA provides a longer time period than the AG before the revision. However, both of them have similar outcomes based on length of hospital stay and cranial defect area. Custom-made 3D titanium implant is a good option for revision cranioplasty to prevent implant failure and reduce patients\' cosmetic concerns.

To study the biocompatibility of nanohydroxyapatite (nmHA)-SiO2 fiber material and its efficacy in guided bone regeneration. ① The cytotoxicity of the nmHA-SiO2 fiber material to MC3T3-E1 cells was determined by CCK-8 assay. The adhesion of cells on the surface of the material was observed. ② Bone defects were prepared in the skull of three groups of New Zealand white rabbits. The following treatments were administered: implantation of nmHA-SiO2, implantation of Bio-Oss, and no treatment. The defects were then covered with nmHA-SiO2 membrane or Hai\'ao oral repair membrane. Animal samples were analyzed by gross observation, micro-computed tomography, hematoxylin-eosin staining and Masson staining. The data were statistically analyzed by multivariate analysis of variance to evaluate the repair of bone defects. ① The nmHA-SiO2 fiber material has suitable biocompatibility. ② The nmHA-SiO2 fiber material performed more effectively as a barrier membrane than other bone substitute materials in GBR model rabbits.

Neurofibromatosis type 1 (NF-1) is the most common neurocutaneous syndrome. It is inherited in an autosomal dominant manner, with many patients having the syndrome as the result of a de novo mutation. NF-1 is caused by a mutation in the NF-1 gene located on the chromosome 17q11.2. NF-1 gene mutations result in the absence or reduced function of neurofibromin protein, thereby promoting tumor development and other clinical findings. NF-1 is fully penetrant, and it is commonly manifested by café-au-lait macules, axillary and/or inguinal freckling, neurofibromas, and Lisch nodules in the eyes. Skeletal manifestations include scoliosis, short stature, long bone dysplasia, and pseudoarthrosis. Rarely, NF-1 can manifest lambdoid suture defects. This report describes the case of a 12-year-old neurofibromatosis patient who presented to the pediatric clinic with a palpable posterior scalp defect, as well as café-au-lait macules and Lisch nodules. Diagnosis of NF-1 was made clinically. MRI and CT scan were done, and the patient was diagnosed with a lambdoid suture defect that is not associated with plexiform neurofibroma. Moreover, whole exome sequence (WES) was done, and diagnosis of NF-1 was confirmed. Watchful waiting and continuous monitoring were the management of choice for this case.

Our case demonstrates a rare genesis of complex scalp defect with exposed dura mater in the occipital region due to self-mutilation. An early interdisciplinary approach is vital to prevent secondary complications and potentially fatal outcomes, particularly in psychiatric patients with reduced health awareness.

Autosomal dominantly inherited neurofibromatosis type I (NF1) is a systemic disorder caused by a mutation of a gene on chromosome 17q11.2 and characterized by multiple café-au-lait spots, lentiginous macules, Lisch nodules of the iris, and tumors of the nervous system. Bony manifestations such as scoliosis, dysplasia of the greater sphenoidal wing, tibial pseudoarthrosis, short stature, and macrocephaly have been reported in approximately 50% of patients. However, calvarial bone defects are rare. After screening 324 articles, 23 cases (12 adult and 11 pediatric patients) of occipital bone defects in NF1 patients were selected. All patients had a single/multiple bone defect over the lambdoid suture. Adjacent benign plexiform neurofibromas were observed in 14 patients (60.8%, 7 adults and 7 children); one adult patient was diagnosed with neurofibrosarcoma. Meningoencephalocele over the occipital defect was noted in 8 cases (34.78%, all adults). Cranioplasty was performed in only 17.39% of patients. Histologic examination was performed in 7 of the 15 patients with associated neurofibromas/neurofibrosarcomas. Biopsy of the bone margins surrounding the defect was performed in only one case. Pathologic examination of the herniated parieto-occipital or cerebellar tissue was not performed in any of the patients studied. We report the case of a 9-year-old girl with NF1 and a significant occipital bone defect and performed a systematic review of the relevant literature to highlight the challenges in treating this condition and to investigate the underlying mechanisms contributing to bone defects or dysplasia in NF1.

UNASSIGNED: Transcranial direct current stimulation (tDCS) has been shown to benefit patients with brain lesions or traumatic brain injury (TBI). These patients usually have skull defects with different sizes and electrical conductivities. There is very little data in the literature that show how to optimally stimulate these patients with the presence of skull defects.
UNASSIGNED: Here we leveraged high-resolution (1 mm) realistic head models to explore the best montages targeting right beneath the skull defects with different sizes and conductivities. Specifically, open-source software ROAST was used to solve for the lead field on the publicly available MIDA model. Four different skull defects/plates were modeled with the center above the right primary motor cortex: a larger defect (10 cm diameter) modeled as either titanium or acrylic plate, and a smaller defect (2.5 cm diameter) modeled as either acute state filled with cerebrospinal fluid (CSF) or chronic state with scar tissue. Optimized stimulation with maximal intensity was run using ROAST targeting the right primary motor cortex.
UNASSIGNED: We show that optimized high-definition montages can achieve an average of 0.3 V/m higher stimulation intensities at the target compared to un-optimized montages (M1-SO or 4×1). Large skull defects with titanium or acrylic plates significantly reduce the stimulation intensity by about 80%, while small defects with acute (CSF) or chronic (scar) tissues significantly increase the stimulation intensity by about 200%. Furthermore, one can use M1-SO to achieve almost the same stimulation strength as the optimized montage if the skull has a large defect with titanium plate, and there is no significant difference in stimulation intensity between 4×1 montage and the optimized montage for small skull defects with scar tissue.
UNASSIGNED: Based on this work, future modeling studies leveraging individual anatomy of skull defects may help guide tDCS practice on patients with skull defects and skull plates.

UNASSIGNED: Acalvaria is a rare congenital malformation in which the flat bones of the cranial vault, dura mater, and associated muscles are absent while the central nervous system usually remains unaffected. It is an extremely rare congenital anomaly with only a handful of cases being reported in literature.
UNASSIGNED: The authors report a case of a 2-month-old male infant with acalvaria who was delivered at home and brought to our centre with the complaint of an abnormally soft skull. He was evaluated in a primary centre in rural Nepal. Parietal bones were missing bilaterally but no other abnormalities were found during the physical examination and investigations. Major differential diagnoses like anencephaly, cephalocele, osteogenesis imperfecta type II, and hypophosphatasia were ruled out with the help of history, physical examination, and available investigations and the case was diagnosed as acalvaria.
UNASSIGNED: Acalvaria is a post-neurulation defect which is associated with anomalies of various organ systems. Radiological diagnosis, with supportive laboratory investigations, is the most reliable method of antenatal diagnosis.
UNASSIGNED: Acalvaria is known to have a dismal prognosis and all the living cases with long-term follow-up are mentally retarded and physically disabled. Early and reliable antenatal diagnosis can reduce the economic, physical, and psychological burden associated with this fatal disease, especially in low-income countries.

Bone defects have a severe impact on the health and lives of patients due to their long-lasting and difficult-to-treat features. Recent studies have shown that there are complex microenvironments, including excessive production of reactive oxygen species. Herein, a surface functionalization strategy using metal-polyphenolic networks was used, which was found to be beneficial in restoring oxidative balance and enhancing osseointegration. The surface properties, biocompatibility, intracellular ROS scavenging, and osseointegration capacity were evaluated, and the therapeutic effects were confirmed using a skull defect model. This approach has great potential to improve complex microenvironments and enhance the efficiency of bone tissue regeneration.

The concept of post-traumatic skull defect closure is based on restoration of anatomical relationships for the maximum possible recovery of brain function, i.e. it is considered as a stage of surgical rehabilitation. The choice of implants in pediatric patients is limited. In this regard, the «gold standard» is still autologous bone implant.
We propose a method for storage and sterilization of autologous bone implant. The last one implies keeping at a temperature of -80 ˚C with sterilization in a vacuum chamber filled with hydrogen peroxide vapors of biocidal plasma medium. Sterilization is provided by 45-minute cycle immediately before surgery. We report skull defect closure using autologous bone implants in 79 patients. Evaluation of effectiveness of storage and sterilization of autologous bone implant included analysis of mechanical properties of bone after sterilization, intra-operative microbiological monitoring, incidence of infections in early postoperative period, follow-up with assessment of resorption.
Early infectious complications occurred in 2 patients (2.5%). Complete resorption with redo surgery occurred in 6 (10.1%) cases. Sterilization in low-temperature plasma of hydrogen peroxide changes mechanical properties of the bone, increases durability under compressive stresses and decreases durability under tensile conditions. This does not affect functional tasks of autologous bone. The proposed method of storage and sterilization is accompanied by low risk of infections and resorption. Storage of autologous bone implant at a temperature of -80 ˚C with subsequent sterilization in low-temperature plasma of hydrogen peroxide can be considered as a safe and effective method for skull defect closure in children after decompressive surgery.
Концепция закрытия посттравматических дефектов черепа основана на восстановлении анатомических соотношений для максимально возможного восстановления функции мозга, т.е. рассматривается как этап хирургической реабилитации. Выбор имплантата с учетом возрастных особенностей для детской категории пострадавших ограничен. С этих позиций золотым стандартом остается использование аутокости.
Предлагается метод хранения и стерилизации аутокости, включающий хранение при температуре –80 ˚C со стерилизацией в вакуумной камере с парами перекиси водорода биоцидной плазменной среды. Стерилизация обеспечивается непосредственно перед операцией 45-минутным циклом. Опыт исследования основан на результатах реконструкции дефекта черепа в 79 наблюдениях с использованием аутокости, предварительно подготовленной согласно разработанному методу. Оценка эффективности метода хранения и подготовки аутотрансплантата включала изучение механических свойств кости после стерилизации, интраоперационный микробиологический мониторинг, частоту встречаемости инфекционно-воспалительных осложнений в раннем послеоперационном периоде, катамнестическое исследование с изучением частоты резорбции аутотрансплантата.
Инфекционные осложнения в раннем периоде зарегистрированы у 2 (2,5%) пациентов. Полная резорбция трансплантата, потребовавшая повторного хирургического лечения, была в 6 (10,1%) случаях. Применение плазменной стерилизации парами перекиси водорода изменяет механические свойства кости и приводит к увеличению прочности в условиях сжимающих напряжений и снижению прочности в условиях растяжения, что не отражается на функциональных задачах применения аутокости. Предлагаемый способ хранения и стерилизации сопровождается низким риском таких осложнений, как инфекция и резорбция.
Хранение аутокости при температуре –80 ˚C с последующей стерилизацией с использованием низкотемпературной плазмы пероксида водорода может рассматриваться как безопасный и эффективный метод подготовки костного аутотрансплантата для закрытия дефектов черепа у детей после декомпрессивной трепанации черепа.

The authors report a case of a patient managed for severe cranial vault depression following combined neurosurgery and radiotherapy. This situation caused major aesthetic discomfort and was potentially dangerous due to the mechanical weakness of the bone flap. The authors had a CAD (computer aided design) silicone elastomer custom-made implant made to fill perfectly the depression. Beforehand, an expansion was performed to cover the implant after removal of the radiated skin. The surgery and post-operative course raised no concerns. After one year of follow-up, the result is very good and the patient very satisfied, proving that this technique certainly has its place in the therapeutic arsenal when faced with a tissue defect of the cranial vault.