Ultrasound as a standalone tool for the management of pediatric calvarial dermoid cysts.

PURPOSE: Calvarial dermoid and epidermoid cysts are benign lesions common in pediatric neurosurgery. Diagnosis is primarily clinical, with frequent but inconsistent use of imaging. Dermoids have been shown to possess distinct sonographic features, but ultrasound (US) remains underutilized in their management. The purpose of this study is to investigate the independent reliability of US in managing pediatric calvarial dermoids and distinguishing them from other calvarial lesions. METHODS: A retrospective review of consecutive patients ≤ 21 years of age with surgically resected calvarial masses between 2017-2024 was performed. Demographic, clinical, and imaging data were analyzed. Pearson chi-squared tests were used for comparison of categorical variables and a binomial linear model was generated controlling for age, lesion tenderness, growth, and suture location. RESULTS: Fifty-nine patients with 61 lesions (31 in females; median age 13 months) were included. Dermoids were more common in younger patients (median age 12 months), along suture lines, and were less likely to present with tenderness (p < 0.001) or rapid growth (p = 0.003). Ultrasound was used in 83% of cases and was the sole imaging modality in 33%. On multivariate analysis, suture location was a significant positive predictor of a dermoid diagnosis (OR = 8.08, 95% CI = 1.67-44.18), while rapid growth was a significant negative predictor (OR = 0.08, 95% CI = 0.003-0.80). CONCLUSION: Ultrasound presents a sensitive and reliable method for the evaluation of most pediatric calvarial lesions, especially dermoid cysts, and warrants being part of standard workup. With appropriate patient selection, US obviates the need for additional imaging in pediatric patients.

An Unusual Presentation of a Primary Chondrosarcoma of the Cranial Vault.

Chondrosarcomas are malignant cartilaginous tumors that usually affect the pelvic bone and long bones. Primary chondrosarcomas of the skull are rare, with the cranial vault being an even more unusual localization. We report a case of a 75-year-old man presenting with headaches and outgrowth of the parietal scalp. CT scan of the head showed an extracranial cystic well-rounded mass originating at the parietal suture and eroding through the adjacent parietal bone. The patient underwent an en bloc surgical resection of the mass, and histological examination confirmed a grade I chondrosarcoma.

Comparing the effects of Bone+B® xenograft and InterOss® xenograft bone material on rabbit calvaria bone defect regeneration.

BACKGROUND: The bone regeneration therapy is often used in patients with inadequate bone support for implants, particularly following tooth extractions. Xenografts derived from animal tissues are effective bone reconstructive options that resist resorption and pose a low risk of transmitting disease. Therefore, these implants may be a good option for enhancing and stabilizing maxillary sinuses. The purpose of this study was to compare two xenografts, Bone+B® and InterOss®, for the reconstruction of rabbit calvaria defects. METHODS AND MATERIALS: The study involved seven male New Zealand white rabbits. In the surgical procedure, 21 spots were created on both sides of the midline calvarium by creating three 8-millimeter defects. A control group was used, as well as two treatment groups utilizing Bone+B® Grafts and InterOss® Grafts. After 3 months, the rabbits were euthanized, followed by pathological evaluation. Analysis of these samples focused on bone formation, xenograft remaining material, and inflammation levels, using Adobe Photoshop CS 8.0 and SPSS version 24. RESULTS: With the application of Bone+B® graft, bone formation ranged from 32% to 45%, with a mean of 37.80% (±5.63), and the remaining material ranged from 28% to 37%, with a mean of 32.60% (±3.65). Using InterOss® grafts, bone formation was 61% to 75%, the mean was 65.83% (±4.75), and the remaining material was 9% to 18%, with a mean of 13.17% (±3.06). The bone formation in the control group ranged from 10% to 25%, with a mean of 17.17% (±6.11). InterOss® had lower inflammation levels than other groups, but the difference was not statistically significant (p > .05). CONCLUSION: InterOss® bone powder is the best option for maxillofacial surgery and bone reconstruction. This is due to more bone formation, less remaining material, and a lower inflammation level. Compared to the control group, Bone+B® improves healing and bone quality, thus making it an alternative to InterOss®.

Tuberculosis of the Parietal Bone in an Indian Boy: A Rare Entity.

Tuberculosis is a common issue in endemic regions. The disease can affect both adults and children. Tuberculosis involving the flat bones of the skull is infrequently reported. Besides, reports of parietal bone tuberculosis in children are rare and a diagnostic challenge. Often, these cases report late, and this could compromise the treatment outcomes. Herein, a case of post-traumatic tuberculosis of the left parietal bone is presented in a child. The diagnosis was achieved by radiometric investigations and the isolation of Mycobacterium tuberculosis from the pus. He was initiated on antituberculous chemotherapy.

Quantifying hominin morphological diversity at the end of the middle Pleistocene: Implications for the origin of Homo sapiens.

OBJECTIVES: The Middle Pleistocene (MP) saw the emergence of new species of hominins: Homo sapiens in Africa, H. neanderthalensis, and possibly Denisovans in Eurasia, whose most recent common ancestor is thought to have lived in Africa around 600 ka ago. However, hominin remains from this period present a wide range of morphological variation making it difficult to securely determine their taxonomic attribution and their phylogenetic position within the Homo genus. This study proposes to reconsider the phenetic relationships between MP hominin fossils in order to clarify evolutionary trends and contacts between the populations they represent. MATERIALS AND METHODS: We used a Geometric Morphometrics approach to quantify the morphological variation of the calvarium of controversial MP specimens from Africa and Eurasia by using a comparative sample that can be divided into 5 groups: H. ergaster, H. erectus, H. neanderthalensis, and H. sapiens, as well as individuals from current modern human populations. We performed a Generalized Procrustes Analysis, a Principal Component Analysis, and Multinomial Principal Component Logistic Regressions to determine the phenetic affinities of the controversial Middle Pleistocene specimens with the other groups. RESULTS: MP African and Eurasian specimens represent several populations, some of which show strong affinities with H. neanderthalensis in Europe or H. sapiens in Africa, others presenting multiple affinities. DISCUSSION: These MP populations might have contributed to the emergence of these two species in different proportions. This study proposes a new framework for the human evolutionary history during the MP.

[Convexity hyperostotic meningioma en plaque: a systematic review]. / Ploskostnye giperostoticheskie meningiomy svoda cherepa. Sistematicheskii obzor literatury.

BACKGROUND: Planar hyperostotic meningiomas account for 2-9% of intracranial meningiomas. They are characterized by planar node following the contours of the inner surface of the skull. Hyperostosis is present in most cases. Timely diagnosis of skull base tumors is usually simple due to early involvement of the cranial nerves. However, convexity meningiomas en plaque usually reach large dimensions that complicates surgery and radiotherapy. OBJECTIVE: To analyze the current state of diagnosis, molecular biology and surgical treatment of hyperostotic meningiomas en plaque. MATERIAL AND METHODS: A systematic review was performed in accordance with the PRISMA guidelines. Searching for literature data included the following keywords: «planar meningioma¼, «hyperostotic meningioma¼, «meningioma en plaque¼, «infiltrative meningioma¼. We reviewed the PubMed and Google Scholar databases until May 2023 and enrolled only full-text Russian-, English- or French-language reports. RESULTS AND DISCUSSION: Among primary 332 reports, 35 references met the inclusion criteria. We found less severity or absence of focal neurological symptoms, comparable incidence of intracranial hypertension and no histological differences between planar and nodular meningiomas. Analysis of molecular biological features of planar meningiomas, including cell cultures, is feasible. There is no consensus regarding surgical treatment and radiotherapy. Most publications are case reports. CONCLUSION: The results of treatment of planar hyperostotic meningiomas, especially large and giant ones, are unsatisfactory. There is no a generally accepted algorithm for treating patients in the literature. This problem requires further research.

Solitary plasmacytoma of the calvarium: A successful management of a long-standing large lesion with a long-term follow-up.

Background: Solitary plasmacytoma of the calvarium (SPC), without evidence of multiple myeloma (MM), is extremely rare. We report a case of a long-standing large SPC that was treated successfully by surgical excision and adjuvant radiotherapy with a long follow-up period. Case Description: A 58-year-old male patient presented with a 5-year history of painless skull swelling. On the physical examination, the mass was 6 × 6 cm in size, oval, not tender, and firm in consistency with normal skin color. A brain computed tomography scan showed a destructive skull lesion. A brain magnetic reasoning imaging (MRI) showed a large expansile lytic mass lesion arising from the skull vault in the frontal-parietal region with multiple internal septa. The patient underwent a craniectomy and excision of the lesion, followed by cranioplasty using methyl methacrylate. The final diagnosis was consistent with plasmacytoma based on the histopathological features. One month follow-up brain MRI showed no evidence of residual tumor. The skeletal survey and bone marrow biopsy did not reveal any evidence of MM. The patient was referred to medical oncology for further treatment and received radiation therapy. During nine years of clinical and radiological follow-up, there was no evidence of any metastasis or recurrence. Conclusion: SPC is a rare disease with high rates of misdiagnosis. Careful evaluations are crucial to exclude systemic involvement. Surgical resection followed by radiotherapy may be adequate for the disease control. Close follow-up with regular lifelong examinations is important to avoid a generalized incurable disease.

The CT and MRI features of benign calvarium and skull base osteoblastoma.

OBJECTIVE: We retrospectively reviewed the CT and MRI features of patients with benign osteoblastoma in the calvarium and skull base (CSBOB). METHODS: Nine cases of pathologically confirmed benign CSBOB were analysed retrospectively. The patients had undergone CT and/or MRI. Tumour location, size, and imaging features were reviewed and recorded. RESULTS: The patients included four males and five females with a mean age of 27.0 years (age 14-40 years). The tumours were located in the frontal bone in 3 patients, the occipital bone in 3 patients, and in the parietal bone, sphenoid bone, and skull base in 1 patient each. On CT, the tumours measured 5.1 ± 3.3 (1.8-8.4) cm. Seven tumours were shown to have caused expansile bony destruction with an eggshell appearance and varying degrees of calcification or matrix mineralization. Multiple septa were observed in 5 tumours. Intracranial growth was observed in 5 tumours. On MRI, 7 tumours showed heterogeneous hypo- to isointensity on T1WI. Heterogeneous high signal patterns with low signal rims and septa were observed in 6 tumours on T2WI, and 4 showed a fluid-fluid level. On contrast-enhanced imaging, 6 tumours showed peripheral and septal enhancement, and 2 showed the dural tail sign. CONCLUSIONS: Benign CSBOB is a rare tumour characterized by expansile bony destruction, septa, a sclerotic rim and calcification or matrix mineralization on CT and MRI. ADVANCES IN KNOWLEDGE: The findings from this study contribute to a better understanding of benign CSBOB and provide valuable imaging features that can aid in its diagnosis and differentiation from other tumours in the calvarium and skull base.

Craniectomy with soft tissue reconstruction for locally advanced non-melanoma skin cancer of scalp with calvarial invasion: The Nottingham experience.

INTRODUCTION: Locally advanced non-melanoma skin cancer (NMSC) involving the periosteum or calvarium poses a clinical challenge for patients who are unfit for immunotherapy due to medical comorbidities and/or frailty. This case series aims to investigate outcomes for patients undergoing craniectomy and soft tissue reconstruction. METHOD: Patients who underwent craniectomy and soft tissue reconstruction for invasive NMSC with calvarium or periosteal invasion between 2016 and 2022 were included. Data, including demographics, operative details, and clinical outcomes, were gathered from Nottingham University Hospitals' digital health record and the histopathology electronic database. RESULT: Eight patients (average age: 78.4 years, 3 females 5 males) with significant comorbidities and varying degrees of periosteal or bone invasion fulfilled the inclusion criteria. Diagnoses included four squamous cell carcinomas, two basal cell carcinomas, and two pleomorphic dermal sarcomas. Five patients had a history of prior incomplete deep margin excision. The median sizes for soft tissue defect, tumor and bone defect size were 51.83 cm2, 34.63 cm2 and 42.25 cm2, respectively. Intraoperative complications included one dural tear. Four patients underwent local flap reconstruction and with split-thickness skin grafting, four patients underwent free flap reconstruction. Adjuvant radiotherapy was administered to three patients. Complications comprised partial graft loss in two and complete graft loss in one. There was partial flap loss in one case. One patient required subsequent parotidectomy due to regional progression before achieving disease control. All patients achieved lasting locoregional disease control (average follow-up 29.7 months). CONCLUSION: Craniectomy with soft tissue reconstruction proves to be a safe and effective treatment option in advanced NMSC of the scalp in patients unsuitable for immunotherapy due to frailty or medical co-morbidity.

Imaging of the Posttreatment Head and Neck: Expected Findings and Potential Complications.

Interpretation of posttreatment imaging findings in patients with head and neck cancer can pose a substantial challenge. Malignancies in this region are often managed through surgery, radiation therapy, chemotherapy, and newer approaches like immunotherapy. After treatment, patients may experience various expected changes, including mucositis, soft-tissue inflammation, laryngeal edema, and salivary gland inflammation. Imaging techniques such as CT, MRI, and PET scans help differentiate these changes from tumor recurrence. Complications such as osteoradionecrosis, chondroradionecrosis, and radiation-induced vasculopathy can arise because of radiation effects. Radiation-induced malignancies may occur in the delayed setting. This review article emphasizes the importance of posttreatment surveillance imaging to ensure proper care of patients with head and neck cancer and highlights the complexities in distinguishing between expected treatment effects and potential complications. Keywords: CT, MR Imaging, Radiation Therapy, Ear/Nose/Throat, Head/Neck, Nervous-Peripheral, Bone Marrow, Calvarium, Carotid Arteries, Jaw, Face, Larynx © RSNA, 2024.

Safety and histopathologic yield of percutaneous CT-guided biopsies of the skull base, orbit, and calvarium.

PURPOSE: Although CT-guided biopsies of the calvarium, skull base, and orbit are commonly performed, the best approaches, efficacy, and safety of such procedures remain scantly described in the literature. This retrospective review of percutaneous biopsies illustrates several approaches to challenging biopsy targets and provides a review of procedural planning considerations and histopathologic yield. METHODS: A retrospective review of CT-guided biopsies of the skull base, calvarium, and orbit between 1/1/2010 and 10/30/2020 was conducted. Patient demographics and procedural factors were recorded, including lesion size and location, biopsy approach, and needle gauge. Outcomes were also noted, including CT dose length product, complications, and histopathologic yield. RESULTS: Sixty-one CT-guided biopsies were included in the final analysis: 34 skull base, 23 calvarial, and 4 orbital lesions. The initial diagnostic yield was 32/34 (94%) for skull base lesions, with one false-negative and one non-diagnostic sample. Twenty-one of twenty-three (91%) biopsies in the calvarium were initially diagnostic, with one false-negative and one non-diagnostic sample. In the orbit, 4/4 biopsies were diagnostic. The total complication rate for the cohort was 4/61 (6.6%). Three complications were reported in skull base procedures (2 immediate and 1 delayed). A single complication was reported in a calvarial biopsy, and no complications were reported in orbital biopsies. CONCLUSION: Percutaneous CT-guided core needle biopsies can be performed safely and with a high diagnostic yield for lesions in the skull base, calvarium, and orbit.

Isolated infantile myofibroma of the calvarium: Report of a case with a literature review.

OBJECTIVE: Infantile myofibromatosis is a rare entity of childhood characterized by benign myofibroblastic tumors in the soft tissues, the bones, and occasionally the viscera. Solitary skeletal lesions are relatively uncommon. Calvarial involvement should be distinguished from more aggressive tumors for appropriate treatment. METHODS: We reviewed solitary infantile myofibroma of the calvarium and discussed the relevant computed tomography and magnetic resonance imaging findings along with differential diagnosis. A case study of the frontal bone in a 5-month-old girl was also presented. RESULTS: Fourteen cases were reviewed, including the current case. Of the 13 cases with known sex, eight were male and five female. The mean age was 3.03 with an age range of 0.41-9 years. Nine of the 14 tumors were in the frontal bone. The lesions were intradiploic with tabula interna and/or externa of the calvaria involvement. The mean largest diameter was 22.3 mm. Upon computed tomography, all the lesions were expansile and lytic, and hypoattenuated, isoattenuated or occasionally hyperatenuated. Calcification was not seen. On magnetic resonance imaging, most neoplasms were hypointense on T1-weighted and T2-weighted images. Neoplasms showed hypointense signal on diffusion-weighted imaging and hyperintense on apparent diffusion coefficient, without restricted diffusion in three cases. All lesions were intensely enhanced after gadolinium administration. Treatment was total surgical resection and recurrence was not observed during follow-up. CONCLUSIONS: Infantile myofibromas are rare, typically intradiploic expansile lytic lesions with tabula interna and/or externa involvement. Distinctive imaging features include the presence of hipointense signals on T2-weighted magnetic resonance images without restricted diffusion on diffusion-weighted imaging. A slow-growing, firm, painless, and nontender mass with supportive imaging findings should raise suspicion of the disease.

Pediatric focal calvarial lesions: an illustrated review.

Focal skull lesions in children can be diagnostically challenging with a wide variety of potential etiologies. Understanding the diverse pathologies and recognizing their associated clinical and imaging characteristics is crucial for accurate diagnosis and appropriate treatment planning. We review pertinent anatomy of the scalp and calvarium and review different pathologies that can present with focal skull lesions in pediatric patients. These include neoplastic, non-neoplastic tumor-like, congenital, post traumatic, and vascular-associated etiologies. We review the key clinical and imaging features associated with these pathologies and present teaching points to help make the correct diagnosis. It is important for radiologists to be aware of the common and rare etiologies of skull lesions as well as the clinical and imaging characteristics which can be used to develop an accurate differential to ensure a timely diagnosis and initiate appropriate management.

The Relationship Between Fetal Central Nervous System Malformations and Modified Myocardial Performance Index.

INTRODUCTION: Fetal ventriculomegaly, the most commonly identified abnormality of the fetal central nervous system (CNS), has been associated with elevated levels of the modified myocardial performance index (mMPI). However, the impact of other CNS pathologies on mMPI has not yet been evaluated. This study aimed to investigate whether there were changes in the myocardial performance index of fetuses with CNS pathologies without congenital heart diseases. METHODS: A total of 126 singleton pregnant women were included in this study. Sixty-three fetuses had fetal CNS abnormalities of acrania, anencephaly, encephalocele, Dandy-Walker malformation, hydrocephalus, and meningocele. The control group consisted of 63 healthy and gestational age-matched fetuses. All ultrasonographic examinations were done in the second trimester of gestation. The data related to the characteristics of pregnant women were evaluated, and fetal left ventricular mMPI was obtained by ultrasound scan. RESULTS: The study and the control group participants were not significantly different by means of pregnancy characteristics. The mean mMPI was higher in the fetal CNS malformation group compared to the control groups (0.39±0.02 vs. 0.45±0.04, P<0.001). The mean mMPI value was similar for fetuses with both closed and open calvarium defects of fetal CNS malformation. CONCLUSION: Fetal CNS anomalies may be associated with prenatal cardiac dysfunction. Moreover, this relationship might be independent of the type of fetal CNS malformation, whether a closed or open calvarium defect.

Augmented effect of fibroblast growth factor 18 in bone morphogenetic protein 2-induced calvarial bone healing by activation of CCL2/CCR2 axis on M2 macrophage polarization.

Fibroblast growth factor (FGF) signaling plays essential roles in various biological events. FGF18 is one of the ligands to be associated with osteogenesis, chondrogenesis and bone healing. The mouse critical-sized calvarial defect healing induced by the bone morphogenetic protein 2 (BMP2)-hydrogel is stabilized when FGF18 is added. Here, we aimed to investigate the role of FGF18 in the calvarial bone healing model. We first found that FGF18 + BMP2 hydrogel application to the calvarial bone defect increased the expression of anti-inflammatory markers, including those related to tissue healing M2 macrophage (M2-Mø) prior to mineralized bone formation. The depletion of macrophages with clodronate liposome hindered the FGF18 effect. We then examined how FGF18 induces M2-Mø polarization by using mouse primary bone marrow (BM) cells composed of macrophage precursors and BM stromal cells (BMSCs). In vitro studies demonstrated that FGF18 indirectly induces M2-Mø polarization by affecting BMSCs. Whole transcriptome analysis and neutralizing antibody treatment of BMSC cultured with FGF18 revealed that chemoattractant chemokine (c-c motif) ligand 2 (CCL2) is the major mediator for M2-Mø polarization. Finally, FGF18-augmented activity toward favorable bone healing with BMP2 was diminished in the calvarial defect in Ccr2-deleted mice. Altogether, we suggest a novel role of FGF18 in M2-Mø modulation via stimulation of CCL2 production in calvarial bone healing.

In vivo evaluation of bone regeneration using ZIF8-modified polypropylene membrane in rat calvarium defects.

AIM: The profound potential of zeolitic imidazolate framework 8 (ZIF8) thin film for inducing osteogenesis has been previously established under in vitro conditions. As the next step towards the clinical application of ZIF8-modified substrates in periodontology, this in vivo study aimed to evaluate the ability of the ZIF8 crystalline layer to induce bone regeneration in an animal model defect. MATERIALS AND METHODS: Following the mechanical characterization of the membranes and analysing the in vitro degradation of the ZIF8 layer, in vivo bone regeneration was evaluated in a critical-sized (5-mm) rat calvarial bone defect model. For each animal, one defect was randomly covered with either a polypropylene (PP) or a ZIF8-modified membrane (n = 7 per group), while the other defect was left untreated as a control. Eight weeks post surgery, bone formation was assessed by microcomputed tomography scanning, haematoxylin and eosin staining and immunohistochemical analysis. RESULTS: The ZIF8-modified membrane outperformed the PP membrane in terms of mechanical properties and revealed a trace Zn+2 release. Results of in vivo evaluation verified the superior barrier function of the ZIF8-coated membrane compared with pristine PP membrane. Compared with the limited marginal bone formation in the control and PP groups, the defect area was almost filled with mature bone in the ZIF8-coated membrane group. CONCLUSIONS: Our results support the effectiveness of the ZIF8-coated membrane as a promising material for improving clinical outcomes of guided bone regeneration procedures, without using biological components.

Apparent diffusion coefficient (ADC) measurements and morphometric evaluation of the cranium in age-matched children with central precocious puberty.

OBJECTIVES: Central precocious puberty (CPP) is one of the common reasons for referral to pediatric endocrinology. Magnetic resonance imaging (MRI) is used to rule out intracranial pathologies. However, there is insufficient information in the literature about bone marrow abnormalities on MRI in CPP cases. The aim of this study was to evaluate the apparent diffusion coefficient (ADC) values obtained from bone marrow diffusion weight images (DWI) of cranial bone structures and the status of sphenooccipital synchondrosis (SOS) in CPP. METHODS: MRI data from 6-to 9-year-old girls with CPP and a healthy control group were evaluated. Anthropometric data, FSH, LH, and oestradiol tests were recorded, and the relationship between SOS status, DWI-ADC values of the clivus, parietal bone, and occipital protuberance were compared. RESULTS: The study included 146 girls, 79 CPP, and 67 healthy aged 6-9 years (median: 8 (2)). The diagnosis age was 8.30 ± 0.8 years. The ADC values were significantly lower on CPP than normal controls (p=<0.05). In the CPP group, pattern 1 was found at 2 % (n=2), pattern 2 at 3.5 % (n=3), and pattern 3 at 3.5 % (n=3) in clivus sphenooccipital synchondrosis. There was no correlation between the mean parietal, occipital, and clivus ADC values and any variable (p>0.05). CONCLUSIONS: DWI-MRI ADC analysis can be used as a quantitative radiological marker for early detection of CPP, even before changes in sphenooccipital synchondrosis.

Does preoperative imaging for scalp non-melanocytic skin cancer accurately predict invasion of the cranial vault? A systematic review and meta-analysis.

PURPOSE: This study aimed to determine the diagnostic accuracy of CT and MRI in the preoperative detection of bone involvement for non-melanoma skin cancers (NMSCs) located on the scalp. This study further aimed to evaluate the predictive value of these imaging modalities in determining the need for craniectomy and to identify gaps in the existing literature. METHODS: Electronic searches of the MEDLINE, Embase, Cochrane and Google Scholar databases were performed for English language studies of any type. Studies reporting detection or exclusion of histopathologically confirmed bone involvement through preoperative imaging were identified according to PRISMA guidelines. Studies reporting dural involvement, non-scalp tumours, and lacking tumour type(s) or outcome data were excluded. Outcomes were preoperative imaging result and histopathologically confirmed bone invasion. Meta-analysis was performed and sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated (excluding case report and MRI data due to insufficient quality and quantity respectively). RESULTS: Four studies with a total of 69 patients were included in the final review, of which two studies totalling 66 patients were included in the meta-analysis. Preoperative CT had a sensitivity of 38%, specificity of 98%, PPV of 90% and NPV of 73%. CONCLUSIONS: The available data suggests that a preoperative CT finding of calvarial involvement by a scalp NMSC is likely to be real, but the absence of such a finding is unreliable. Current evidence suggests that preoperative imaging cannot exclude the necessity for craniectomy and future research is needed, particularly on the role of MRI.

Cranial Bone Changes Induced by Mild Traumatic Brain Injuries: A Neglected Player in Concussion Outcomes?

Mild traumatic brain injuries (TBIs), particularly when repetitive in nature, are increasingly recognized to have a range of significant negative implications for brain health. Much of the ongoing research in the field is focused on the neurological consequences of these injuries and the relationship between TBIs and long-term neurodegenerative conditions such as chronic traumatic encephalopathy and Alzheimer's disease. However, our understanding of the complex relationship between applied mechanical force at impact, brain pathophysiology, and neurological function remains incomplete. Past research has shown that mild TBIs, even below the threshold that results in cranial fracture, induce changes in cranial bone structure and morphology. These structural and physiological changes likely have implications for the transmission of mechanical force into the underlying brain parenchyma. Here, we review this evidence in the context of the current understanding of bone mechanosensitivity and the consequences of TBIs or concussions. We postulate that heterogeneity of the calvarium, including differing bone thickness attributable to past impacts, age, or individual variability, may be a modulator of outcomes after subsequent TBIs. We advocate for greater consideration of cranial responses to TBI in both experimental and computer modeling of impact biomechanics, and raise the hypothesis that calvarial bone thickness represents a novel biomarker of brain injury vulnerability post-TBI.