Split Calvarial Grafting for Closure of Large Cranial Defects: The Ideal Option?

How Does Diploic Space Thickness Change With Age?

BACKGROUND

Cranial defects from trauma, surgery, or congenital conditions require precise reconstruction to restore cranial vault integrity. Autogenous calvarial grafts are preferred for their histocompatibility and biomechanical properties, but their success depends on a well-developed diploic space. Although prior studies have described overall skull thickness development, less is known about how diploic thickness changes through adulthood. This study aimed to quantify diploic thickness and density changes with age using computed tomography (CT) imaging.

METHODS

A retrospective review of an institution-wide imaging database was performed to identify patients who received CT scans for non-traumatic indications. A total of 110 patients, balanced by sex, were selected across 11 age groups spanning 10 to 109 years. Each patient's skull was aligned to a standardized grid and segmented in 3-dimensional (3D) Slicer using consistent thresholding values to isolate the diploic space from the inner and outer cortical tables. Linear regression models were used to assess the effects of age and sex on diploic thickness.

RESULTS

No statistically significant trends were found between age and diploic thickness (r=-0.06; P=0.50. However, a near-significant trend of decreasing diploic thickness with age was observed in men (r=-0.25; P=0.05) but not in women (r=0.11; P=0.42). The posteromedial parietal region consistently showed the greatest thickness across all age groups. Diploic density also increased significantly with age (r=0.285; P=0.002), indicating progressive ossification of cancellous bone.

CONCLUSION

Diploic thickness remains stable across the lifespan with slight sex-based differences. However, examination reveals that the density of the diploe increases over time, suggesting age-related changes in cancellous architecture. These findings highlight the importance of individual anatomical variations when harvesting autogenous calvarial grafts to optimize cranial reconstruction outcomes.

Oncological outcomes of partial thickness calvarial resection for locally advanced scalp malignancies

OBJECTIVE

Traditionally, locally advanced scalp malignancies have been managed through composite, full-thickness calvarial resection. The aim of this study is to explore the oncologic outcomes of partial calvarial resection for locally invasive scalp malignancies without medullary space invasion, employing a burr-down approach.

STUDY DESIGN

Retrospective case series.

SETTING

Tertiary referral center.

METHODS

This study analyzed records of 26 adult patients diagnosed with scalp cancer that spread to the calvarial region. Data collected included demographics, medical history, adjuvant therapy details, imaging, surgical outcomes, and postoperative oncological results.

RESULTS

26 patients with cancerous scalp lesions necessitating calvarial resection for deep margin control were identified in 22 men and 4 women. Mean age at diagnosis was 72.7 years. The most common histopathological diagnosis was Squamous cell carcinoma (n = 16). Partial removal of the calvarial lesions was achieved in all patients without any intraoperative complications. Twelve patients received adjuvant therapy consisting of the following modalities: radiation (6), chemotherapy (1), immunotherapy (1), a combination of immunotherapy and radiation (2), and a combination of chemotherapy and radiotherapy (2). There was a total of 7 recurrences: local (n = 3,11.5 %), regional (n = 3,11.5 %), distal (n = 1,3.8 %). Long term local control was achieved in (n = 23,88.4 %) of patients. The mean time of follow-up was 19.1 months, and the mean time to recurrence was 15.1 months.

CONCLUSION

Partial calvarial resection represents a viable, safe, and effective surgical technique for cancerous tissue removal, reducing risks associated with full thickness calvarial resection, and enhancing soft tissue healing when compared to the established gold standard.

How Partial Skull Defect Affects Vulnerability of the Skull in Traumatic Situations: A Biomechanical Study

BACKGROUND

Part of the skull can be lost due to neurosurgical diseases or trauma. Skulls with partial defects can develop different fracture patterns from those of intact skulls. This study aims to clarify the differences.

METHODS

A 3-dimensional skull model was produced by referring to the computer-tomography data of a 23-year-old intact male volunteer. We defined the model as Intact Model. Another model was produced by removing part of the frontal bone, which was defined as Defect Model. Dynamic simulations of impacts were performed varying the site and direction of impact. Fracture patterns caused by the impacts were calculated using dynamic analysis software (LS-DYNA; Livermore Software Technology Corp.) and were compared between the intact model and defect model.

RESULTS

When Defect Model was impacted, fracture involved wider areas than when Intact Model was impacted. This finding was observed not only when Defect Model was impacted on its defect side but also when it was impacted on its intact side.

CONCLUSIONS

When a skull carrying a defect on one side is impacted, serious fracture occurs even when the non-defect side is impacted, meaning that a skull with a defect is vulnerable to impacts on the non-defect side. This finding should be taken into consideration in deciding indications of skull defect reconstruction.

Biocompatible Materials for Orbital Wall Reconstruction-An Overview

The reconstruction of an orbit after complex craniofacial fractures can be extremely demanding. For satisfactory functional and aesthetic results, it is necessary to restore the orbital walls and the craniofacial skeleton using various types of materials. The reconstruction materials can be divided into autografts (bone or cartilage tissue) or allografts (metals, ceramics, or plastic materials, and combinations of these materials). Over time, different types of materials have been used, considering characteristics such as their stability, biocompatibility, cost, safety, and intraoperative flexibility. Although the ideal material for orbital reconstruction could not be unanimously identified, much progress has been achieved in recent years. In this article, we summarise the advantages and disadvantages of each category of reconstruction materials. We also provide an update on improvements in material properties through various modern processing techniques. Good results in reconstructive surgery of the orbit require both material and technological innovations.