Background: Glioblastoma (GBM) remains the most aggressive primary brain tumor, and intraoperative frozen section analysis is the current standard for rapid histopathological assessment. However, this approach is time-consuming and resource-intensive. Stimulated Raman scattering (SRS) imaging has emerged as a label-free technique enabling near real-time microscopic evaluation of fresh tissue. This study compares the visualization of selected histopathological features in a newly developed intraoperative SRS system with conventional hematoxylin–eosin (HE) staining in confirmed GBM. Methods: Tumor samples from 30 patients with neuropathologically confirmed GBM were analyzed. For each case, both HE-stained frozen sections and SRS-generated virtual HE-like images were prepared from separate portions of the specimen. Twelve neuropathologists with varying levels of experience assessed 60 images according to seven predefined GBM criteria, resulting in 720 image evaluations. Feature detection was analyzed using cluster-adjusted generalized estimating equation models, and interobserver agreement was assessed using Fleiss’ κ. Results: Descriptively, hypercellularity and hypervascularization were identified at similar frequencies in both modalities, whereas pleomorphism, endothelial proliferation, mitotic activity, and necrosis were more often recognized in HE images. In cluster-adjusted analyses, SRS showed significantly lower detection rates for hypercellularity, pleomorphism, endothelial proliferation, and mitotic activity, while no significant difference was observed for hypervascularization, necrosis, or pseudopalisading after false discovery rate correction. Interobserver agreement was feature-dependent and generally higher for HE than SRS, particularly for hypercellularity. Conclusions: In this feature-level analysis of neuropathologically confirmed GBM, SRS imaging provided rapid, label-free morphological information and showed comparable visualization of selected histopathological features, particularly hypervascularization. While conventional HE-stained frozen sections remained superior for certain WHO-defining features, SRS represents a promising intraoperative adjunct that may complement established neuropathological workflows. Further studies including non-tumor tissue and a broader range of glioma grades are needed to determine the full diagnostic accuracy and clinical applicability of this technique.

Objective: Epigenetic tumor characteristics are in focus for glioblastoma prognosis. This raises the question if these characteristics present with stable expression during the progression of the disease, and if potential temporal instability might influence their prognostic value. Methods: A total of 44 patients suffering from glioblastoma who were treated for their primary and relapse tumors were included in the study. Tumor specimens from the initial and recurrent tumor resection were subjected to evaluation of MGMT, p15, and p16 methylation statuses. MiRNA-21, -24, -26a, and -181d expression was evaluated as well. The stability of these epigenetic markers during the progression of the disease was correlated with further clinical data. A Cancer Genome Atlas (TCGA) dataset of 224 glioblastoma patients was used as an independent cohort to validate the results. Results: Instability was observed in all examined epigenetic markers. MGMT methylation changed in 30% of patients, p15 methylation changed in 35%, and p16 methylation changed in 37.5% of cases. MiRNA expression in corresponding initial and relapse tumor specimens varied considerably in general, individual cases presented with a stable expression. Patients with a decreased expression of miRNA-21 in their recurrence tumor showed significantly longer overall survival. These results are supported by the data from TCGA indicating similar results. Conclusions: Epigenetic characteristics may change during the course of glioblastoma disease. This may influence the prognostic value of derived molecular markers.

Mixed reality (MR) has the potential to enhance the accuracy and effectiveness of spine surgery, particularly in the placement of pedicle screws. This technology can lead to improved outcomes, optimized ergonomics, and reduced operative time and costs. This study evaluates the efficacy and accuracy of MR in thoracolumbar pedicle screw placement using neuronavigation and a head-mounted device. We conducted a prospective review of the initial series of thoracolumbar pedicle screw placements utilizing neuronavigation (Brainlab) and MR with a head-mounted device (MagicLeap2). Data from 22 patients were analyzed, involving a total of 144 pedicle screws placed. The Gertzbein-Robbins classification (GRC) was used to assess screw position: Grade A (screw within the pedicle), Grade B (breach 6 mm). Grades A and B were considered accurate placements. Out of 144 thoracolumbar pedicle screws, 139 were accurately positioned according to GRC grades A and B, resulting in a clinical accuracy rate of 96.5%. The mean deviation at the bone entry point compared to preoperative plans was 2.35 ± 1.1 mm, with a mean angular deviation of 3.1 ± 1.4°. Surgeons reported no issues with the head-mounted device, including dizziness or headaches, and noted no limitations in visualization of the surgical field. This study demonstrates the successful application of MR combined with neuronavigation for precise pedicle screw placement, eliminating the need for fluoroscopy and enhancing surgical efficiency.

Arachnoiditis ossificans (AO) associated with syringomyelia (SM) is a rare pathology. Its clinical and image-based diagnostic features are challenging to identify. Only a limited number of cases have been published thus far. We present two new cases and offer a review of the literature. We conducted a systematic literature search using PubMed, Web of Science, and Google Scholar with the following keywords: Arachnoiditis ossificans, leptomeningeal calcification, and spinal meningeal calcification, in combination with syrinx, syringomyelia, hydromyelia, cord cavitation, and cystic necrosis of the spinal cord. AO-SM predominantly affected females (12 F, 7 M), with a mean age of 55.84 ± 14.7 years. The mean follow-up was 14.07 ± 9.01 months postoperatively. The main complaints included low back pain and progressive para-/tetraparesis, with or without urinary disturbances. Potentially causative events occurred 25.07 ± 13.75 years prior to diagnosis. Based on imaging findings, patients primarily experienced thoracic AO-SM. In seven studies, arachnoid cysts were reported in association with AO-SM. Surgical treatment mainly involved microsurgical AO resection, shunting, or draining of the SM, along with duraplasty and cystectomy or fenestration of the arachnoid cyst. A second surgical intervention was conducted on five patients. Approximately 57% of the patients showed improvement. AO-SM remains one of the least understood causes of myelopathy. Clinical and imaging diagnostics continue to pose challenges. Preoperative evaluation using magnetic resonance imaging (MRI) and native CT may be regarded as the gold standard. CT myelography and, occasionally, Cine MRI should be considered to determine the best surgical option. Surgical treatment continues to be a dilemma.