Significance of navigated transcranial magnetic stimulation and tractography to preserve motor function in patients undergoing surgery for motor eloquent gliomas.

Resection of gliomas in or close to motor areas is at high risk for morbidity and development of surgery-related deficits. Navigated transcranial magnetic stimulation (nTMS) including nTMS-based tractography is suitable for presurgical planning and risk assessment. The aim of this study was to investigate the association of postoperative motor status and the spatial relation to motor eloquent brain tissue in order to increase the understanding of postoperative motor deficits. Patient data, nTMS examinations and imaging studies were retrospectively reviewed, corticospinal tracts (CST) were reconstructed with two different approaches of nTMS-based seeding. Postoperative imaging and nTMS-augmented preoperative imaging were merged to identify the relation between motor positive cortical and subcortical areas and the resection cavity. 38 tumor surgeries were performed in 36 glioma patients (28.9% female) aged 55.1 ± 13.8 years. Mean distance between the CST and the lesion was 6.9 ± 5.1 mm at 75% of the patient-individual fractional anisotropy threshold and median tumor volume reduction was 97.7 ± 11.6%. The positive predictive value for permanent deficits after resection of nTMS positive areas was 66.7% and the corresponding negative predictive value was 90.6%. Distances between the resection cavity and the CST were higher in patients with postoperative stable motor function. Extent of resection and distance between resection cavity and CST correlated well. The present study strongly supports preoperative nTMS as an important surgical tool for preserving motor function in glioma patients at risk.

Risk factors for prolonged length of stay after first single-level lumbar microdiscectomy.

OBJECTIVE: The objective is to identify risk factors that potentially prolong the hospital stay in patients after undergoing first single-level open lumbar microdiscectomy. METHODS: A retrospective single-centre study was conducted. Demographic data, medical records, intraoperative course, and imaging studies were analysed. The outcome measure was defined by the number of days stayed after the operation. A prolonged length of stay (LOS) stay was defined as a minimum of one additional day beyond the median hospital stay in our patient collective. Bivariate analysis and multiple stepwise regression were used to identify independent factors related to the prolonged hospital stay. RESULTS: Two hundred consecutive patients who underwent first lumbar microdiscectomy between 2018 and 2022 at our clinic were included in this study. Statistical analysis of factors potentially prolonging postoperative hospital stay was done for a total of 24 factors, seven of them were significantly related to prolonged LOS in bivariate analysis. Sex (p = 0.002, median 5 vs. 4 days for females vs. males) and age (rs = 0.35, p ≤ 0.001, N = 200) were identified among the examined demographic factors. Regarding preoperative physical status, preoperative immobility reached statistical significance (p ≤ 0.001, median 5 vs. 4 days). Diabetes mellitus (p = 0.043, median 5 vs. 4 days), anticoagulation and/or antiplatelet agents (p = 0.045, median 5 vs. 4 days), and postoperative narcotic consumption (p ≤ 0.001, median 5 vs. 4 days) as comorbidities were associated with a prolonged hospital stay. Performance of nucleotomy (p = 0.023, median 5 vs. 4 days) was a significant intraoperative factor. After linear stepwise multivariable regression, only preoperative immobility (p ≤ 0.001) was identified as independent risk factors for prolonged length of postoperative hospital stay. CONCLUSION: Our study identified preoperative immobility as a significant predictor of prolonged hospital stay, highlighting its value in preoperative assessments and as a tool to pinpoint at-risk patients. Prospective clinical trials with detailed assessment of mobility, including grading, need to be done to verify our results.

Surgical Outcome of Patients With Supratentorial Meningiomas Aged 80 Years or Older-Retrospective International Multicenter Study.

BACKGROUND AND OBJECTIVES: Demographic changes will lead to an increase in old patients, a population with significant risk of postoperative morbidity and mortality, requiring neurosurgery for meningiomas. This multicenter study aims to report neurofunctional status after resection of patients with supratentorial meningioma aged 80 years or older, to identify factors associated with outcome, and to validate a previously proposed decision support tool. METHODS: Neurofunctional status was assessed by the Karnofsky Performance Scale (KPS). Patients were categorized in poor (KPS ≤40), intermediate (KPS 50-70), and good (KPS ≥80) preoperative subgroups. Volumetric analyses of tumor and peritumoral brain edema (PTBE) were performed; volumes were scored as small (<10 cm 3 ), medium (10-50 cm 3 ), and large (>50 cm 3 ). RESULTS: The study population consisted of 262 patients, and the median age at surgery was 83.0 years. The median preoperative KPS was 70; 117 (44.7%) patients were allotted to the good, 113 (43.1%) to the intermediate, and 32 (12.2%) to the poor subgroup. The median tumor and PTBE volumes were 30.2 cm 3 and 27.3 cm 3 ; large PTBE volume correlated with poor preoperative KPS status ( P = .008). The 90-day and 1-year mortality rates were 9.0% and 13.2%, respectively. Within the first postoperative year, 101 (38.5%) patients improved, 87 (33.2%) were unchanged, and 74 (28.2%) were functionally worse (including deaths). Each year increase of age associated with 44% (23%-70%) increased risk of 90-day and 1-year mortality. In total, 111 (42.4%) patients suffered from surgery-associated complications. Maximum tumor diameter ≥5 cm (odds ratio 1.87 [1.12-3.13]) and large tumor volume (odds ratio 2.35 [1.01-5.50]) associated with increased risk of complications. Among patients with poor preoperative status and large PTBE, most (58.3%) benefited from surgery. CONCLUSION: Patients with poor preoperative neurofunctional status and large PTBE most often showed postoperative improvements. The decision support tool may be of help in identifying cases that most likely benefit from surgery.

Influence of clinical and tumor-specific factors on the resting motor threshold in navigated transcranial magnetic stimulation.

OBJECTIVE: Preoperative non-invasive mapping of motor function with navigated transcranial magnetic stimulation (nTMS) has become a widely used diagnostic procedure. Determination of the patient-individual resting motor threshold (rMT) is of great importance to achieve reliable results when conducting nTMS motor mapping. Factors which contribute to differences in rMT of brain tumor patients have not been fully investigated. METHODS: We included adult patients with all types of de novo and recurrent intracranial lesions, suspicious for intra-axial brain tumors. The outcome measure was the rMT of the upper extremity, defined as the stimulation intensity eliciting motor evoked potentials with amplitudes greater than 50µV in 50 % of applied stimulations. RESULTS: Eighty nTMS examinations in 75 patients (37.5 % female) aged 57.9 ± 14.9 years were evaluated. In non-parametric testing, rMT values were higher in patients with upper extremity paresis (p = 0.024) and lower in patients with high grade gliomas (HGG) (p = 0.001). rMT inversely correlated with patient age (rs=-0.28, p = 0.013) and edema volume (rs=-0.28, p = 0.012) In regression analysis, infiltration of the precentral gyrus (p<0.001) increased rMT values. Values of rMT were reduced in high grade gliomas (p<0.001), in patients taking Levetiracetam (p = 0.019) and if perilesional edema infiltrated motor eloquent brain (p<0.001). Subgroup analyses of glioma patients revealed similar results. Values of rMT did not differ between hand and forearm muscles. CONCLUSION: Most factors confounding rMT in our study were specific to the lesion. These factors contributed to the variability in cortical excitability and must be considered in clinical work with nTMS to achieve reliable results with nTMS motor mapping.

Embolization of the middle meningeal artery vs. second surgery-treatment response and volume course of recurrent chronic subdural hematomas.

BACKGROUND: Despite multiple studies on the embolization of the middle meningeal artery, there is limited data on the treatment response of recurrent chronic subdural hematomas (CSDH) to embolization and on the volume change. METHODS: We retrospectively compared the treatment response and volume change of recurrent CSDHs in a conventional group (second surgery) with an embolization group (embolization as stand-alone treatment) during the time-period from August 2019 until June 2022. Different clinical and radiological factors were assessed. Treatment failure was defined as necessity of treatment for second recurrence. Hematoma volumes were determined in the initial CT scan before first surgery, after the first surgery, before retreatment as well as in an early (1 day-2 weeks) and in a late follow-up CT scan (2-8 weeks). RESULTS: Fifty recurrent hematomas after initial surgery were treated either by second surgery (n = 27) or by embolization (n = 23). 8/27 (26,6%) surgically treated and 3/23 (13%) of the hematomas treated by embolization needed to be treated again. This leads to an efficacy in recurrent hematomas of 73,4% in surgically treated and of 87% in embolized hematomas (p = 0.189). In the conventional group, mean volume decreased significantly already in the first follow-up CT scan from 101.7 ml (SD 53.7) to 60.7 ml (SD 40.3) (p = 0.001) and dropped further in the later follow-up scan to 46.6 ml (SD 37.1) (p = 0.001). In the embolization group, the mean volume did decrease insignificantly from 75.1 ml (SD 27.3) to 68 ml (SD 31.4) in the first scan (p = 0.062). However, in the late scan significant volume reduction to 30.8 ml (SD 17.1) could be observed (p = 0.002). CONCLUSIONS: Embolization of the middle meningeal artery is an effective treatment option for recurrent CSDH. Patients with mild symptoms who can tolerate slow volume reduction are suitable for embolization, whereas patients with severe symptoms should be reserved for surgery.

Assessing the feasibility of mapping the tibialis anterior muscle with navigated transcranial magnetic stimulation in neuro-oncologic patients.

Mapping the lower extremity with navigated transcranial magnetic stimulation (nTMS) still remains challenging for the investigator. Clinical factors influencing leg mapping with nTMS have not been fully investigated yet. The aim of the study was to identify factors which influence the possibility of eliciting motor evoked potentials (MEPs) from the tibialis anterior muscle (TA). Patient records, imaging, nTMS examinations and tractography were retrospectively evaluated. 48 nTMS examinations were performed in 46 brain tumor patients. Reproducible MEPs were recorded in 20 patients (41.67%). Younger age (p = 0.044) and absence of perifocal edema (p = 0.035, Cramer's V = 0.34, OR = 0.22, 95% CI = 0.06-0.81) facilitated mapping the TA muscle. Leg motor deficit (p = 0.49, Cramer's V = 0.12, OR = 0.53, 95%CI = 0.12-2.36), tumor entity (p = 0.36, Cramer's V = 0.22), tumor location (p = 0.52, Cramer's V = 0.26) and stimulation intensity (p = 0.158) were no significant factors. The distance between the tumor and the pyramidal tract was higher (p = 0.005) in patients with successful mapping of the TA. The possibility to stimulate the leg motor area was associated with no postoperative aggravation of motor deficits in general (p = 0.005, Cramer's V = 0.45, OR = 0.63, 95%CI = 0.46-0.85) but could not serve as a specific predictor of postoperative lower extremity function. In conclusion, successful mapping of the TA muscle for neurosurgical planning is influenced by young patient age, absence of edema and greater distance to the CST, whereas tumor entity and stimulation intensity were non-significant.

Therapeutic Potential of Selenium in Glioblastoma.

Little progress has been made in the long-term management of malignant brain tumors, leaving patients with glioblastoma, unfortunately, with a fatal prognosis. Glioblastoma remains the most aggressive primary brain cancer in adults. Similar to other cancers, glioblastoma undergoes a cellular metabolic reprogramming to form an oxidative tumor microenvironment, thereby fostering proliferation, angiogenesis and tumor cell survival. Latest investigations revealed that micronutrients, such as selenium, may have positive effects in glioblastoma treatment, providing promising chances regarding the current limitations in surgical treatment and radiochemotherapy outcomes. Selenium is an essential micronutrient with anti-oxidative and anti-cancer properties. There is additional evidence of Se deficiency in patients suffering from brain malignancies, which increases its importance as a therapeutic option for glioblastoma therapy. It is well known that selenium, through selenoproteins, modulates metabolic pathways and regulates redox homeostasis. Therefore, selenium impacts on the interaction in the tumor microenvironment between tumor cells, tumor-associated cells and immune cells. In this review we take a closer look at the current knowledge about the potential of selenium on glioblastoma, by focusing on brain edema, glioma-related angiogenesis, and cells in tumor microenvironment such as glioma-associated microglia/macrophages.

Medulloblastoma in adults - reviewing the literature from a surgeon's point of view.

Medulloblastoma is a common primary brain tumor in children but it is a rare cancer in adult patients. We reviewed the literature, searching PubMed for articles on this rare tumor entity, with a focus on tumor biology, advanced neurosurgical opportunities for safe tumor resection, and multimodal treatment options. Adult medulloblastoma occurs at a rate of 0.6 per one million people per year. There is a slight disparity between male and female patients, and patients with a fair skin tone are more likely to have a medulloblastoma. Patients present with cerebellar signs and signs of elevated intracranial pressure. Diagnostic efforts should consist of cerebral MRI and MRI of the spinal axis. Cerebrospinal fluid should be investigated to look for tumor dissemination. Medulloblastoma tumors can be classified as classic, desmoplastic, anaplastic, and large cell, according to the WHO tumor classification. Molecular subgroups include WNT, SHH, group 3, and group 4 tumors. Further molecular analyses suggest that there are several subgroups within the four existing subgroups, with significant differences in patient age, frequency of metastatic spread, and patient survival. As molecular markers have started to play an increasing role in determining treatment strategies and prognosis, their importance has increased rapidly. Treatment options include microsurgical tumor resection and radiotherapy and, in addition, chemotherapy that respects the tumor biology of individual patients offers targeted therapeutic approaches. For neurosurgeons, intraoperative imaging and tumor fluorescence may improve resection rates. Disseminated disease, residual tumor after surgery, lower radiation dose, and low Karnofsky performance status are all suggestive of a poor outcome. Extraneural spread occurs only in very few cases. The reported 5-year-survival rates range between 60% and 80% for all adult medulloblastoma patients.