Bilateral Foramina Parietalia Permagna - A Calvarial Defect Caused by Haploinsufficiency of the Msh Homeobox 2 Gene: A Case Report and Current Literature Review.

Foramina parietalia permagna (FPP) is a rare anatomical defect that affects the parietal bones of the human skull. FPP is characterized by symmetric perforations on either side of the skull, which are caused by insufficient ossification during embryogenesis. These openings are typically abnormally large and can range from a few millimeters to several centimeters in diameter. Enlarged foramina are often discovered incidentally during anatomical or radiological examinations and in most cases left untreated unless symptoms develop. Although this calvarial defect is usually asymptomatic, it may be accompanied by neurological or vascular conditions that can have clinical significance in certain cases. FPP is an inherited disorder and arises due to mutations in either Msh homeobox 2 (MSX2) or aristaless-like homeobox 4 (ALX4) genes. In almost all cases, one parent is affected. Clinical findings and diagnostic imaging typically contribute to determine the diagnosis.

Repair of Congenital Enlarged Parietal Foramina With Porous Polyethylene Implants.

Enlarged biparietal foramina is an autosomal dominant disorder that is caused by a failure of completion of ossification within the parietal bones. Enlarged parietal foramina measuring more than a few millimeters are uncommon. Even though spontaneous regression has been described, closure is rarely complete, and depending on the size of the resulting defect, an unprotected brain is a concern. There are few reports on the surgical management of persistent enlarged biparietal foramina. This is the first report describing our experience with a custom porous polyethylene implant.

Giant epidermoid cyst penetrating the skull: a case report and literature review.

Intracranial epidermoid cyst is a rare pseudotumor of the nervous system, accounting for 0.2%-1.8% of all intracranial tumors. It is usually located in the cerebellopontine Angle or parasellar area, with insipid onset, slow growth and usually less than 2 cm in diameter. Giant epidermoid cysts that invade the bone have rarely been reported in the literature. Herein, we report a case of giant ECs extradural to the parietal bone, penetrating the skull and continuing to expand outward. In addition, a systematic search of four authoritative databases was conducted to collect the relevant reports of giant epidermoid cyst with diameter > 5cm for the first time, and to discuss the clinical and radiographic features of patients with giant epidermoid cyst and the influence of treatment options.

Quantitative study of the primary ossification centre of the parietal bone in the human fetus.

BACKGROUND: Detailed morphometric data concentrating on the development of primary ossification centres in human fetuses is critical for the early detection of developmental defects. Thus, an understanding of the growth and development of the parietal bone is crucial in assessing both the normal and pathological development of the calvaria. MATERIALS AND METHODS: The size of the parietal primary ossification centre in 37 spontaneously aborted human fetuses of both sexes (16 males and 21 females) aged 18-30 weeks was studied by means of computed tomography, digital-image analysis and statistics. RESULTS: The numerical data of the parietal primary ossification centre in the human fetus displays neither sex nor laterality differences. With relation to fetal age in weeks, the parietal primary ossification centre grew in sagittal diameter according to the quadratic function: y = 16.322 + 0.0347 × (age)² ± 1.323 (R² = 0.96), in projection surface area according to the cubic function: y = 284.1895 + 0.051 × × (age)³ ± 0.490, while in both coronal diameter and volume according to the quartic functions: y = 21.746 + 0.000025 × (age)4 ± 1.256 and y = 296.984 + + 0.001 × (age)4, respectively. CONCLUSIONS: The obtained morphometric data of the parietal primary ossification centre may be considered age-specific references, and so may contribute to the estimation of gestational ages and be useful in the diagnostics of congenital cranial defects.

Biparietal osteodystrophy: Macroscopic appearance, computed tomography imaging and microarchitectural analysis.

Anatomical or morphological variations of the skull bones usually do not attract much attention among forensic pathologists. However, these variations can sometimes be an important marker in forensic identification of a person or represent a missing piece when solving a cranial trauma puzzle. In this article, we were interested in peculiar presentation of the thinning of both parietal bones (biparietal osteodystrophy). The course and etiology of this condition still remain unknown. In three autopsy cases with biparietal osteodystrophy (three females aged 95, 90 and 83) and no head trauma, we used conventional (CT) and microcomputed tomography (micro-CT) imaging of the skull and parietal bone specimens containing normal bone, transitional zone and thinned bone with osteodystrophy. CT images demonstrated an oval-shaped resorptive parietal bone depression with smooth contours, without marginal osteosclerotic changes or involvement of cranial sutures. In the transitional zone, micro-CT scans showed a decrease in total bone thickness and the thickness of diplöe, while inner and outer tables showed increased porosity. At the site of maximal thinness of the parietal bone, inner and outer tables fused and formed a thin layer of cortical bone. Skull thinning appeared due to the reduced thickness of diplöe, leading to egg-shell thinning in the central area of the parietal bones. A forensic pathologist should be familiar with this benign condition in order not to confuse it with resorptive bone diseases.

Parietal bone thickness for predicting operative transfusion and blood loss in patients undergoing spring-mediated cranioplasty for nonsyndromic sagittal craniosynostosis.

OBJECTIVE: Variables that can predict outcomes in patients with craniosynostosis, including bone thickness, are important for surgical decision-making, yet are incompletely understood. Recent studies have demonstrated relative risks and benefits of surgical techniques for correcting head shape in patients with nonsyndromic sagittal craniosynostosis. The purpose of this study was to characterize the relationships between parietal bone thickness and perioperative outcomes in patients who underwent spring-mediated cranioplasty (SMC) for nonsyndromic sagittal craniosynostosis. METHODS: Patients who underwent craniectomy and SMC for nonsyndromic sagittal craniosynostosis at a quaternary pediatric hospital between 2011 and 2021 were included. Parietal bone thickness was determined on patient preoperative CT at 27 suture-related points: at the suture line and at 0.5 cm, 1.0 cm, 1.5 cm, and 2.0 cm from the suture at the anterior parietal, midparietal, and posterior parietal bones. Preoperative skull thickness was compared with intraoperative blood loss, need for intraoperative transfusion, and hospital length of stay (LOS). RESULTS: Overall, 124 patients with a mean age at surgery ± SD of 3.59 ± 0.87 months and mean parietal bone thickness of 1.83 ± 0.38 mm were included in this study. Estimated blood loss (EBL) and EBL per kilogram were associated with parietal bone thickness 0.5 cm (ρ = 0.376, p < 0.001 and ρ = 0.331, p = 0.004; respectively) and 1.0 cm (ρ = 0.324, p = 0.007 and ρ = 0.245, p = 0.033; respectively) from the suture line. Patients with a thicker parietal bone 0.5 cm (OR 18.08, p = 0.007), 1.0 cm (OR 7.16, p = 0.031), and 1.5 cm (OR 7.24, p = 0.046) from the suture line were significantly more likely to have undergone transfusion when controlling for age, sex, and race. Additionally, parietal bone thickness was associated with hospital LOS (ß 0.575, p = 0.019) when controlling for age, sex, and race. Patient age at the time of surgery was not independently associated with these perioperative outcomes. CONCLUSIONS: Parietal bone thickness, but not age at the time of surgery, may predict perioperative outcomes including transfusion, EBL, and LOS. The need for transfusion and EBL were most significant for parietal bone thickness 0.5 cm to 1.5 cm from the suture line, within the anticipated area of suturectomy. For patients undergoing craniofacial surgery, parietal bone thickness may have important implications for anticipating the need for intraoperative transfusion and hospital LOS.

Craniofacial orientation and parietal bone morphology in adult modern humans.

In adult humans, the orbits vary mostly in their orientation in relation to the frontal bone profile, while the orientation of the cranial base and face are associated with the anteroposterior dimensions of the parietal bone. Here we investigate the effect of parietal bone length on the orientation of the orbits, addressing craniofacial integration and head orientation. We applied shape analysis to a sample of computed tomography scans from 30 adult modern humans, capturing the outlines of the parietal and frontal bones, the orbits, and the lateral and midline cranial base, to investigate shape variation, covariation, and modularity. Results show that the orientation of the orbits varies in accordance with the anterior cranial base, and in association with changes in parietal bone longitudinal extension. Flatter, elongated parietal bones are associated with downwardly oriented orbits and cranial bases. Modularity analysis points to a significant integration among the orbits, anterior cranial base, and the frontal profile. While the orbits are morphologically integrated with the adjacent structures in terms of shape, the association with parietal bone size depends on the spatial relationship between the two blocks. Complementary changes in orbit and parietal bone might play a role in accommodating craniofacial variability and may contribute to maintain the functional axis of the head. To better understand how skull morphology and head posture relate, future studies should account for the spatial relationship between the head and the neck.

Mechanical and morphological properties of parietal bone in patients with sagittal craniosynostosis.

Limited information is available on the effect of sagittal craniosynostosis (CS) on morphological and material properties of the parietal bone. Understanding these properties would not only provide an insight into bone response to surgical procedures but also improve the accuracy of computational models simulating these surgeries. The aim of the present study was to characterise the mechanical and microstructural properties of the cortical table and diploe in parietal bone of patients affected by sagittal CS. Twelve samples were collected from pediatric patients (11 males, and 1 female; age 5.2 ± 1.3 months) surgically treated for sagittal CS. Samples were imaged using micro-computed tomography (micro-CT); and mechanical properties were extracted by means of micro-CT based finite element modelling (micro-FE) of three-point bending test, calibrated using sample-specific experimental data. Reference point indentation (RPI) was used to validate the micro-FE output. Bone samples were classified based on their macrostructure as unilaminar or trilaminar (sandwich) structure. The elastic moduli obtained using RPI and micro-FE approaches for cortical tables (ERPI 3973.33 ± 268.45 MPa and Emicro-FE 3438.11 ± 387.38 MPa) in the sandwich structure and diploe (ERPI1958.17 ± 563.79 MPa and Emicro-FE 1960.66 ± 492.44 MPa) in unilaminar samples were in strong agreement (r = 0.86, p < .01). We found that the elastic modulus of cortical tables and diploe were correlated with bone mineral density. Changes in the microstructure and mechanical properties of bone specimens were found to be irrespective of patients' age. Although younger patients are reported to benefit more from surgical intervention as skull is more malleable, understanding the material properties is critical to better predict the surgical outcome in patients <1 year old since age-related changes were minimal.

The Incidence of Depressed Skull Fractures Due to the Use of Pin-Type Head Frame Systems in the Adult Population: 10-year Experience of a Single Neurosurgical Center.

OBJECTIVE: Pin-type head frame systems have become a worldwide standard procedure, but they can cause some complications on rare occasions. This study aimed to examine the incidence and associated risk factors of depressed skull fracture and related intracranial hematoma (DSFH) due to the use of head frames in our institute over the past 10 years. METHODS: This study included 1749 patients who underwent neurosurgical surgeries using pin-type head frames, including the Mayfield (Integra NeuroSciences, Plainsboro, NJ) skull clamp (721 cases) and the Sugita (Mizuho Ikakogyo Co., Ltd., Tokyo, Japan) head frame (1028 cases). We retrospectively reviewed hospital records of our institute to identify cases of DSFH, and documented the type of head frame used, as well as patient characteristics. RESULTS: The incidence of DSFH was 0.29% (5 of 1749 cases). All 5 cases had an associated epidural hematoma, with a single case having an additional dural laceration (without subdural damage). All perforation sites, located at the parietal bone near the pterion, occurred by the unilateral horizontal screw of the Sugita head frame. None of the patients experienced postoperative neurological decline. CONCLUSIONS: Even in the adult population, the DSFH by the pin-type head frame can occur infrequently. Based on our results, we recommend that the following factors should be considered when the pin-type head frame is used for neurosurgical procedures: location of pin application, thickness and fragility of the skull, and adequate control of compressive forces exerted by the head frame.

Primary osteosarcoma of the parietal bone.

Osteosarcoma is the most common primary bone tumor and usually involves the long bones. Osteosarcoma of the skull, on the other hand, is relatively rare. Here, we present a 29-year-old man with a growing mass in the skull he first noticed after a fall while skateboarding. The initial clinical diagnosis was hematoma. While undergoing an evacuation surgery for a hematoma, a suspicious mass was detected which was biopsied. Histopathological evaluation showed high-grade osteosarcoma. The patient was referred to our hospital where he underwent definitive resection followed by adjuvant chemotherapy. His course was complicated by wound infection. Even though osteosarcoma of the skull is a rare finding, it should be suspected in a patient with a skull mass, and the history of prior head trauma does not exclude the diagnosis.

The parietal foramen anatomy: studies using dry skulls, cadaver and in vivo MRI.

OBJECTIVE: The aim of this study was to describe the anatomical features encountered in the parietal foramen in a series of 178 human bones and 123 head MRI examinations. A cadaveric specimen was also dissected to demonstrate the trajectory of a superficial scalp vein through the parietal foramen as far as the dura mater. A literature review was performed regarding prevalence of parietal foramen in different populations. METHODS: Totally, 178 paired adult bones were used to investigate the presence, shape and number of the parietal foramina. In addition, 123 brain MRI examinations were also studied. RESULTS: The parietal foramina were encountered in 75/89 (84.3%) skulls [32/38 (84.2%) in women vs. 43/51 (84.3%) in men, p > 0.05]. The parietal foramen was present bilaterally in 44.73% of females and 54.9% of males. Regarding unilaterality of the parietal foramen, a right or left laterality was observed in female 21% right versus 18% left; and 16% versus 14% (left) in males (p > 0.05). The accessory parietal foramen was present in the right parietal in 2.6% and in 7.9% on the left side of the females, while 5.9% and 3.9% of the males on the right or left sides, respectively. The parietal foramina located in the proximity of the sagittal suture (male 7.1 ± 2.5 mm vs. female, 7.4 ± 2.7 mm). There was a positive correlation between the right and left parietal foramina regarding the distance from the median line. The distance from a foramen to the contralateral one was 16 ± 4 mm in men and 18 ± 5 mm in women, respectively (p > 0.05). CONCLUSION: No major differences were encountered between sexes regarding the anatomical features of parietal foramen.

Accessory Cranial Suture Leading to Abnormal Head Shape.

ABSTRACT: Accessory cranial sutures have been described in the literature and are most commonly associated with the parietal bone. These sutures are typically identified incidentally and there have been no reported cases of accessory cranial sutures leading to abnormal head shape.The authors present the case of a 3-month-old patient with multiple congenital anomalies and an accessory parietal suture leading to abnormal head shape. The patient was successfully treated with cranial orthotic therapy. To our knowledge, this is the first reported case of an accessory cranial suture leading to abnormal head shape.

Vascularized Composite Parietal Bone Flap for Immediate Reconstruction of a Hemi-Maxillectomy Defect in an Infant.

BACKGROUND: Surgical resection of maxillary tumors can result in defects that can be difficult to reconstruct by conventional means due to the complex functional and anatomic nature of the midface and lack of regional bone flap options in the head and neck. Many reconstructive methods have been used to repair maxillary defects, but the ideal technique for the reconstruction of hemi-maxillectomy defects in growing pediatric patients has yet to be determined. METHODS: The authors present a rare pediatric patient with melanotic neuroectodermal tumor of infancy resulting in a hemi-maxillectomy defect after resection that was reconstructed using a pedicled vascularized composite flap consisting of temporalis muscle, pericranium, and parietal bone. RESULTS: The patient achieved successful long-term bony reconstruction of his right maxilla with this flap. Stable skeletal fixation with adequate orbital support was maintained over a >3-year follow-up period. CONCLUSION: A vascularized composite parietal bone flap is a reliable reconstructive option for reconstruction of large maxillectomy defects providing low donor-site morbidity, adequate globe support, excellent long-term skeletal stability, and malar symmetry in rapidly growing pediatric patients. Successful reconstruction for a rare patient with maxillary melanotic neuroectodermal tumor of infancy requiring hemi-maxillectomy was demonstrated with >3-year follow-up.

Quantitative bone single photon emission computed tomography analysis of the effects of duration of bisphosphonate administration on the parietal bone.

Effects of long-term bisphosphonate (BP) administration on the metabolism of healthy bone and the concomitant changes in imaging are unclear. Hence, we aimed to retrospectively investigate the effects of long-term BP administration on the intact parietal bone using the standardised uptake value (SUV) derived from single photon emission computed tomography (SPECT). We enrolled 29 patients who had odontogenic infection, osteoporosis, bone metastasis cancer, or rheumatoid arthritis, and classified them into BP-naïve: A (14 patients) and BP-treated: B, < 4 years (7 patients) and C, ≥ 4 years (8 patients) groups. We measured the maximum bilateral SUV (SUVmax) of the parietal bone using quantitative bone SPECT software. There were significant differences in the duration of BP administration and SUVmax of the parietal bone among the diseases (P < 0.0001 and P = 0.0086, respectively). There was a positive correlation between the duration of BP administration and SUVmax of the parietal bone (rs = 0.65, P = 0.0002). The SUVmax was significantly different between A and B (P = 0.02) and between A and C (P = 0.0024) groups. This is the first report on the correlation between long-term BP administration and the SUVmax of the parietal bone using the quantitative bone SPECT analysis.

[Osteoblastoma of the parietal bone of the cranial vault: about a case]. / Ostéoblastome de l'os pariétal de la voûte du crâne: à propos d'un cas.

Osteoblastoma is an uncommon primary bone tumor. Its occurrence in the cranial vault is extremely rare. We here report our first case of right parietal bone osteoblastoma in a 46-year old woman with a history of benign cranial traumas. She reported progressive painful, non-inflammatory right parietal bone swelling. Craniocerebral CT scan showed hyperdense bone lesion with sparing of the internal table of the right parietal bone. The patient first underwent biopsy, then complete resection of the bone lesion with methyl-methacrylic cement cranioplasty. The postoperative course was uneventful. Anatomopathological examination showed osteoblastoma with no sign of malignancy. This study and literature review highlight the clinical manifestation, the radiological and anatomopathological features as well as the management of osteoblastoma of the parietal bone of the cranial vault.

Outcome of Epidural Hematoma: Lessons from Solitary Fibrous Tumor/Hemangiopericytoma.

BACKGROUND: Intracranial solitary fibrous tumor (SFT)/hemangiopericytoma (HPC) is rare. In this report, a case of epidural hematoma (EDH) that eventually evolved into SFT/HPC is presented. We describe the possible association between the 2 diseases, which has not been previously reported. CASE DESCRIPTION: A 40-year-old man suffered from an EDH in the right parietal area 12 years ago and accepted conservative treatment. Follow-up computed tomography (CT) scan shows that the density of the right EDH gradually changed from uniform slightly lower density to mixed density. A new CT scan revealed an epidural mass extending to the subcutaneous with local bone destruction. An operation was performed via a large right parietal craniotomy, and the final diagnosis was World Health Organization grade III SFT/HPC after histopathologic examination and immunohistochemical verification. The patient died of deterioration of brain disease 3 months after the final diagnosis. CONCLUSIONS: To our knowledge, this is the first report that HPC occurred in the epidural cavity. We are the first time to describe the possible association between EDH and HPC.

Aggressive Cranial Osteoblastoma of the Parietotemporo-Occipital Bone: A Case Report and Review of Literature with Special Emphasis on Recurrence/Residue.

Osteoblastoma is a rare nonfibroblastic osteoid tissue-forming primary bony tumor usually arising in the medullary cavity/diploic space of any bone. The calvarium is an extremely rare site of its origin. Clinically, 2 types of osteoblastoma are noted: benign/conventional/typical and aggressive/high grade. Their imaging features are nondifferentiating and nonspecific, histopathologic features have a few subtle but nonspecific differences, and they have highly distinct clinical behavior. We report an extremely rare case of a patient with large aggressive cranial osteoblastoma, who developed massive inoperable multifocal recurrence 15 months after total en bloc resection with wide margins. A concise review of cases of aggressive osteoblastomas involving the cranium available in the English literature is also presented as an update.

Posterior Calvarial Augmentation for Chiari Malformation Type 1 Refractory to Foramen Magnum Decompression.

BACKGROUND: Chiari 1 malformation is a structural abnormality of the hindbrain and posterior fossa characterized by herniation of the cerebellar tonsils through the foramen magnum. Although asymptomatic in some cases, hindbrain herniation can be associated with disruption of cerebrospinal fluid flow dynamics at the craniovertebral junction and syrinx formation, leading to symptoms. Foramen magnum decompression with or without duraplasty has been the most commonly performed surgical procedure in the management of this condition. The management of syringomyelia associated with Chiari malformation is more challenging and controversial. Although the associated syrinx can significantly improve after craniovertebral decompression and restoration of cerebrospinal fluid flow, in some cases, it will persist despite decompressive surgery and could even continue to enlarge. CASE DESCRIPTION: We have described the case of a 4-year-old boy with non-craniosynostotic Chiari malformation and extensive cervical syrinx who, despite foramen magnum decompression and further revision, continued to deteriorate clinically and radiologically. Posterior calvarial augmentation was performed as a salvage procedure, with resolution of the tonsillar herniation and syrinx. CONCLUSIONS: Posterior calvarial augmentation is a viable option for patients with Chiari malformation refractory to foramen magnum decompression.