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Oral e-Poster Presentations - Booth 1: Vascular 3, September 27, 2023, 10:00 AM - 10:40 AM
Background: Despite current clinical guidelines recommending suboccipital decompressive craniectomy (SDC) in patients with space-occupying cerebellar infarction when neurological deterioration occurs, the precise definition of such deterioration remains unclear. The current study aimed at characterizing whether clinical outcomes can be predicted by the GCS score immediately prior to SDC, and whether higher GCS scores are associated with better clinical outcomes. We aimed to characterize whether clinical outcomes can be predicted by the GCS score immediately prior to SDC, and if higher GCS scores are associated with better clinical outcomes.
Methods: In a single-center, retrospective analysis of 51 patients treated with SDC for space-occupying cerebellar infarction clinical and imaging data were evaluated at the timepoints of symptom onset, hospital admission and preoperatively. Clinical outcome was measured by mRS at the last available follow-up. Preoperative GCS scores were stratified into three groups (GCS 3-8, 9-11 and 12-15). Univariate and multivariate Cox regression analyses were performed using clinical and radiological parameters as predictors of clinical outcome.
Results: In Cox-regression analysis using mRS of 1-2 as a positive clinical outcome we found a significant increase in the proportional hazard ratio (HR) of 6.581 [CI 1.839-36.414]; p=0.031 for GCS scores of 12-15 prior to SDC. Clinical outcomes (mRS 3-6) were associated with infarct volume above 6.0 cm3 (HR 2.473 [CI 1.209-5.057]; p=0.013), tonsillar herniation (HR: 0.279 [CI 0.083-0.933]; p=0.038), brainstem compression (HR 0.304 [CI 0.123-0.749]; p=0.010) and a preoperative GCS score of 3-8 (HR 2.386 [CI 1.160-4.906]; p=0.018).
Conclusions: SDC should be considered in patients with infarct volumes above 6.0 cm3 with GCS scores higher than previously described in the literature, as these patients may show better long-term outcome than those in which surgery is delayed until a GCS score of 11 or lower.
The oxidation state of sulfur in slab fluids is controversial, with both dominantly oxidized and reduced species proposed. Here we use in situ X-ray absorption spectroscopy analysis of sulfur-in-apatite to monitor changes in the oxidation state of sulfur during high-P metasomatism by slab fluids in the subduction channel. Our samples include a 73 cm continuous transect of reaction zones between a metagabbroic eclogite block and serpentinite matrix from a mélange zone on the island of Syros, Greece. The block core consists of garnet, omphacite, phengite, paragonite, epidote-clinozoisite, and rutile. In this region, apatite is only observed as elongate inclusions in omphacite cores. From the core outwards micas are increasingly replaced by epidote-clinozoisite, garnets are smaller and more frequent, pyrite + bornite is observed as inclusions in recrystallized omphacite, and apatite is increasingly abundant in the matrix and inclusions in garnet. A major transition at 48 cm separates an assemblage of Ca-Na amphibole, omphacite, chlorite, pyrite, and apatite from the inner garnet-bearing eclogite assemblages. Omphacite disappears from the assemblage at ~56 cm and amphibole compositions sharply transition to tremolite at 59 cm. Finally, the assemblage tremolite + talc + pyrite is observed after ~70 cm.Apatites in the eclogite assemblages exclusively display S6+ peaks in their absorption spectra. This includes apatite inclusions in omphacite in the least altered lithology, as well as matrix apatite and isolated apatite inclusions in garnet in the outermost metasomatized eclogite zone. In the intermediate pyrite-rich (~1-5 vol %) amphibole + omphacite + chlorite zone, apatite displays a strong S1- absorption peak in most grains, with rare analyses showing mixed S1- and S6+. Finally, apatite in the outermost tremolite-bearing assemblages only displays a S6+ peak. The pyrite-rich zone at 48 cm occurs at the initial interface between the serpentinite matrix and eclogite block, characterized by a dramatic decrease in Na content and Mg#. Our data suggest that reduction of S6+ in infiltrating fluids to S1- in pyrite became focused as Fe diffused across the steep Mg# gradient, resulting in pyrite precipitation. In contrast, S reduction in the Mg-rich tremolite-dominant portions of the transect was limited by a lack of Fe, resulting in low modes of pyrite and fluid buffered S6+ in apatite. Finally, S6+-bearing apatite is also observed in reaction zone lithologies from elsewhere on Syros, suggesting our observations are not isolated.Two important conclusions are drawn from these data and observations: (1) In the case of Syros, slab fluids at eclogite-facies conditions carried oxidized S6+, and (2) The interaction of these fluids with eclogites composed of ferrous-Fe silicates resulted in extensive sulfide precipitation.
Garnet xenocrysts from kimberlites provide unique insights into the composition, structure and evolution of the subcontinental lithospheric mantle (SCLM). For example, different metasomatic events in the SCLM are reflected in compositional differences between garnet xenocrysts. As mantle metasomatism largely controls the physical and chemical properties of the SCLM, it exerts first order control over the genesis of kimberlitic magmas and diamond formation. However, dating mantle lithologies and processes is complicated by high ambient temperatures that allow the equilibration of most isotopic systems up to the time of kimberlite eruption. As a consequence, the temporal connection between metasomatic events in the mantle and kimberlite genesis is commonly ambiguous.
In this study, we applied LA-ICPMS U-Pb dating to 43 harzburgitic, lherzolithic and megacrystic garnet xenocrysts from the ~376 Ma diamondiferous V. Grib kimberlite, Russia, in order to investigate the link between different types of mantle metasomatism and kimberlite genesis.
Our results indicate that, with two possible exceptions, only harzburgitic garnet overlaps in age with the kimberlite eruption, whereas lherzolitic and megacrystic garnet crystals are ~20 to 130 million years older. Furthermore, garnet U-Pb ages and Ni-in-garnet temperatures of ~820 to 1200 °C do not correlate. This, and the high closure temperature of U-Pb in garnet (≥900 °C) suggests that the garnet U-Pb ages indeed reflect metasomatic events in the SCLM. However, the U-Pb ages could also reflect cooling ages. In this case, the metasomatic events recorded in the garnet crystals must still have occurred up to ~130 million years prior to the eruption of the V. Grib kimberlite.
These findings have far-reaching implications for the genesis of (diamondiferous) kimberlites, as they clearly show that the time lag between metasomatic events in the SCLM, as recorded in kimberlitic garnet xenocrysts, and kimberlite eruption may extend to tens of millions of years.
Introduction: The optimal treatment of patients with spinal infections remains a controversial topic. Within Europe, fundamentally different therapeutic concepts are found. Therefore, the aim of this study was to compare the outcome of patients who received surgical vs. antibiotic treatment alone for primary pyogenic spondylodiscitis in an international cohort analysis.
Materials and Methods: The retrospectively compiled databases of tertiary high-volume spine centers served as the baseline for this study. All documented cases of primary spondylodiscitis treated surgically and conservatively in the period of 2017-2022 were included and grouped according to the therapeutic concept: conservative vs. surgical treatment. Independent investigators collected the relevant clinical and radiological data. The primary endpoint of this study was mortality rate; secondary endpoints were relapse rate and persisting neurological deficit.
Results: A total of 392 patients were included in the analysis (155 females with a mean age of 68 years). Of these, 95 cases were treated conservatively (CoT) and 297 cases were treated surgically (SuT). There was no significant difference (p<0.01) related to patient’s disease characteristics: Lumbar was the main location (n=240, CoT 58/ SuT 182, p=0.97) followed by thoracic (n=70, CoT 24/ SuT 46, p=0,03) and cervical (n=47, CoT 7/ SuT 40, p=0.11) region. A multilocular spinal infection was present in 32 patients (CoT 3/ SuT 29, p=0.04). 181 cases (CoT 36/ SuT 145, p=0.06) presented with an epidural abscess. Neurological deficits were recorded in 100 cases (CoT 26/ SuT 74, p=0.63), and septic conditions in 88 cases (CoT 26/ SuT 62, p=0.19). Pre-existing conditions like Diabetes (p=0.57), renal failure (p= 0.97), hepatopathy (p= 0.15), malignoma (p=0.39) or i.v. drug abuse (p=0.93) did also not differ between the groups. The mortality rate of all conservatively treated was 24.2% (23 cases) and 6.7% (20 cases) in all surgically treated patients (p<0.001). A follow-up of ≥ 6 weeks was available in 289 cases (CoT 83, SuT 206 ). In this subset of patients relapse of infection occurred in six (7.2%) and 23 (11.2%) cases in the conservative and early surgical treatment group, respectively (p=0.69). Persisting neurological deficit was recorded in 21 (25.3%) of conservatively treated and 51 (24.8%) of surgically treated cases (p=0.92).
Conclusion: Whereas relapse rates and persisting neurological deficit were not found to differ significantly, the results of this international data analyses, with their respective limitations, clearly support the growing evidence of a significantly reduced mortality rate after surgical therapy for primary pyogenic spondylodiscitis when compared to conservative treatment regimen.
Introduction: Spondylodiscitis is the commonest form of infectious disease of the spine and harbours a high mortality rate of up to 20%. Recent demographic trends in Germany, such as an aging population, immunosuppression, and intravenous drug use, suggest that the incidence of spondylodiscitis may be on the rise. However, the exact epidemiological development of the disease remains uncertain. This study aims to analyse the burden on the tertiary healthcare system in Germany using data from the Federal Statistical Office of Germany (FSOG) database.
Materials and Methods: All cases of spondylodiscitis diagnosed between 2005 and 2021 were identified from the FSOG database. The study characterised the mean duration of hospital stays, total and population-adjusted number of diagnoses made, age-stratified incidence, and outcomes of hospitalised patients.
Results: A total of 131,982 diagnoses for spondylodiscitis were identified between 2005 and 2021. The number of diagnoses for spondylodiscitis has doubled during this period, from 5.4/100,000 population in 2005 to 11/100,000 population in 2021. The highest increase in admissions was recorded for those aged 90 years and above (+1307%), 80-89 (+376%) and 70-79 (+99%). Hospital discharges to rehabilitation facilities have increased by 160%, and discharges against medical advice by 91%. On the other hand, during the analysed period, the in-hospital mortality rate has decreased by 52%.
Conclusion: The population-adjusted incidence of spondylodiscitis in Germany has more than doubled between 2005 and 2021, highlighting the clinical relevance of this disease. During the same period, in-hospital mortality dropped by half. These findings suggest the need for further investigation into optimal therapy, particularly the role and timing of surgical treatment.
Spinal Tumors / Infections (Spine Parallel Session v.3), September 27, 2023, 8:30 AM - 10:00 AM
Background: The optimal treatment of patients with spinal infections remains a controversial topic. While there is some consensus regarding the indication for surgical intervention in infections with neurologic deficit, significant deformity or progressive disease, other situations remain controversial. Within Europe, fundamentally different therapeutic concepts are found. Therefore, the aim of this study was to compare the outcome of patients who received surgical vs. antibiotic treatment alone for primary pyogenic spondylodiscitis in an international cohort analysis.
Methods: The retrospectively compiled databases of tertiary high-volume spine centers served as the baseline for this study. All documented cases of primary spondylodiscitis treated surgically and conservatively in the period of 2017-2022 were included and grouped according to the therapeutic concept: conservative vs. surgical treatment. Independent investigators collected the relevant clinical and radiological data. The primary endpoint of this study was mortality rate; secondary endpoints were relapse rate and persisting neurological deficit.
Results: A total of 392 patients were included in the analysis (155 females and 237 males with a mean age of 68 years). Of these, 95 cases were treated conservatively (CoT) and 297 cases were treated surgically (SuT). Most of conservatively treated patients were treated in the United Kingdom (CoT 81/ SuT 7), while most of the surgically treated cases were treated in Germany (CoT 14/ SuT 290). There was no significant difference (p<0.01) related to patient’s disease characteristics:
Lumbar was the main location (n=240, CoT 58/ SuT 182, p=0.97) followed by thoracic (n=70, CoT 24/ SuT 46, p=0,03) and cervical (n=47, CoT 7/ SuT 40, p=0.11) region. A multilocular spinal infection was present in 32 patients (CoT 3/ SuT 29, p=0.04). 181 cases (CoT 36/ SuT 145, p=0.06) presented with an epidural abscess. Neurological deficits were recorded in 100 cases (CoT 26/ SuT 74, p=0.63), and septic conditions in 88 cases (CoT 26/ SuT 62, p=0.19). Pre-existing conditions like Diabetes (CoT 20/, SuT 71, p=0.57), renal failure (CoT 19/ SuT 60, p= 0.97), hepatopathy (CoT 4/ SuT 26, p= 0.15), malignoma (CoT 9/ SuT 38, p=0.39) or i.v. drug abuse (CoT 5/, SuT 15, p=0.93) did also not differ between the groups.
The mortality rate of all conservatively treated was 24.2% (23 cases) and 6.7% (20 cases) in all surgically treated patients (p<0.001). A follow-up of ≥ 6 weeks was available in 289 cases (CoT 83, SuT 206 ). In this subset of patients relapse of infection occurred in six (7.2%) and 23 (11.2%) cases in the conservative and early surgical treatment group, respectively (p=0.69). Persisting neurological deficit was recorded in 21 (25.3%) of conservatively treated and 51 (24.8%) of surgically treated cases (p=0.92).
Conclusions: Whereas relapse rates and persisting neurological deficit were not found to differ significantly, the results of this international data analyses, with their respective limitations, clearly support the growing evidence of a significantly reduced mortality rate after surgical therapy for primary pyogenic spondylodiscitis when compared to conservative treatment regimen.
Oral e-Poster Presentations - Booth 3: Spine 2 (Tumors), September 26, 2023, 4:10 PM - 4:50 PM
Background: Spinal metastasis remains a persistent and oftentimes urgent challenge in the neurosurgical operating room. We aim to understand metastatic spread to the spinal bone on a molecular level in endothelial cells and tumor cells to facilitate improved therapeutic approaches and diagnostics.
Methods: We established a murine syngeneic spinal bone metastasis model. In vivo dissemination was first evaluated using fluorescent beads, followed by murine cancer cell lines (B16, LLC1). We investigated short-term seeding and long-term growth to identify correlations between seeding and tumor formation. EphrinB2-Eph4 interaction has been described as a crucial mediator of spinal bone metastasis. Transient (pharmacological) and permanent (genetical) ephrinB2-Eph4 interventions were performed.
Results: Dissemination of microbeads to distinct spinal segments depended on segment and particle size. Disseminated tumor cells on the contrary showed less frequent arrest in the bone and equal distribution among segments. EphrinB2 intervention changed the dissemination behavior towards the lumbar segment. Interestingly, only transient intervention retained this distribution, permanent ephrinB2 depletion on endothelial cells (efnb2iΔEC) resulted in equal dispersion of metastases. Histological staining revealed a reduction of Endomucin (Emcn) positive structures in combination with a reduction of Type H (Emcn high/CD31 high) endothelial cells in naïve efnb2iΔEC animals. In tumor tissue, these Type H endothelial cells were unaffected. However, an increase in CD31-expressing endothelial cells was observed under endothelial ephrinB2 depletion. These CD31-expressing endothelial cells have been recently described as Type E (Emcn low/CD31 high) and implicated in angiogenesis and osteogenesis.
Conclusions: We here describe a subpopulation of endothelial cells in efnb2iΔEC mice that seems to resemble pro-angiogenic and possibly pro-adhesive type E endothelial cells. Based on these finding we propose a compensatory pro-angiogenic mechanism in efnb2iΔEC mice that is highjacking pre-existing developmental pathways, which is critical for late-stage spinal metastatic growth independent of the initial seeding and extravasation of metastatic cells.
Oral e-Poster Presentations - Booth 2: Neuro-Oncology C (Imaging&Monitoring), September 27, 2023, 1:00 PM - 2:30 PM
Background: Repetitive TMS (rTMS) can be used to non-invasively map cortical language areas. Commonly, frequencies of 5-10 Hz are used to induce speech errors. We could recently show that frequencies of 30 and 50 Hz are advantageous to achieve higher reliability. However, high-frequent rTMS applied over perisylvian regions still suffer from limited tolerability. Using short-train or paired-pulse TMS (pp-TMS) might offer a good alternative to rTMS to interfere with speech production. In this study, we, therefore, compared 30 Hz rTMS to pp-TMS aiming at improved language mapping.
Methods: 13 healthy, right-handed subjects (f=6, 25-41 years) were investigated using two different rTMS protocols: (i) 30 Hz rTMS and (ii) pp-TMS. TMS protocols were applied in a pseudo-randomized order during a picture naming task (picture-to-trigger interval: 0 ms) over cortical language areas. In a subsequent study, we compared pp-TMS also to short trains of three TMS pulses and repetitive paired pulse TMS. Language errors were post-hoc analysed by two independent raters and were assigned to eight different error categories. The level of pain was assessed on a subjective 0-10 numeric rating scale (NRS). Moreover, language error distribution was analysed using a cortical parcellation system.
Results: 30 Hz rTMS evoked a significantly higher number of errors than the pp-protocol, i.e., 18 ± 12 % vs. 10 ± 7 % (p<0.05). However, pp-TMS was significantly better tolerated with a mean NRS of 2.3 ± 1.6 vs. 3.4 ± 1.5 (p<0.05, FDR-corrected). Of note, pp-TMS could induce a higher number of anomias (15 ± 15 %) than repetitive TMS protocols (4 ± 7 %; p<0.1, FDR-corrected), but less dysarthria. The cortical distribution of errors differed between the two protocols. The results of train-of-three TMS were similar to the pp-TMS protocol.
Conclusions: Due to its better tolerability, pp-TMS might offer the possibility to stimulate regions which are particularly prone to direct facial / trigeminal nerve stimulation, e.g., the inferior frontal gyrus. Moreover, pp-TMS seems advantageous for mapping patients who are comparatively susceptible to rTMS side effects and with regard to safety in general.