BACKGROUND: The most widely used classifications of adverse events (AEs) in neurosurgery define their severity according to the therapy used to treat them. This concept has substantial shortcomings because it does not reflect the severity of AEs that are not treated, such as new neurological deficits. OBJECTIVE: To present a novel multidimensional and patient-centered classification of the severity of AE in neurosurgery and evaluate its applicability. METHODS: The Therapy-Disability-Neurology (TDN) grading system classifies AEs depending on the associated therapy, disability, and neurological deficits. We conducted a 2-center retrospective observational study on 6071 interventions covering the whole neurosurgical spectrum with data prospectively recorded between 2013 and 2019 at 2 institutions from 2 countries. RESULTS: Using the first patient cohort (4680 interventions), a positive correlation was found between severity of AE and LOS as well as treatment cost. Each grade was associated with a greater deterioration of the Karnofsky Performance Status Scale (KPS) at discharge and at follow-up. When using the same methods on the external validation cohort (1391 interventions), correlations between the grades of AE, LOS, and KPS at discharge were even more pronounced. CONCLUSION: Our results suggest that the TDN grade is consistent with clinical and economic repercussions of AE and thus reflects AE severity. It is easily interpreted and enables comparison between different medical centers. The standardized report of the severity of AE in the scientific literature could constitute an important step forward toward a more critical, patient-centered, and evidence-based decision-making in neurosurgery.

Cystic schwannomas have only been reported in a few case reports/series. As a result, they may be misdiagnosed and a standardized management approach remains challenging to establish. The aim of this study was to compile all reported cases of cystic schwannomas and analyze the perioperative course based on a systematic review of the literature with an additional two cases from the authors’ experience. We conducted a search of MEDLINE and CENTRAL databases for spinal intradural extramedullary cystic schwannomas, in accordance to the PRISMA statement. All title/abstracts were screened, and a full-text review of the remaining articles was conducted. The results were compiled in tables and summarized using means and standard deviation (SD), median and interquartile range, and percentage and 95% confidence intervals. We identified 263 articles, of which 35, which reported 54 cases, were included. Including our case-reports (n = 56), patients had a mean age of 47.7 years (SD ± 13.0 years) at presentation, 57% were males, and most lesions were lumbar (43%). The most common symptoms were pain (82%) and muscle weakness (68%) with 84% of patients showing neurological findings. 70% of patients showed a complete relief of symptoms after surgery and 96% reported improvement. Only four complications were reported. Schwannomas should be considered in the differential diagnosis of intradural extramedullary cystic lesions. Patients typically present with subacute to chronic pain and/or neurologic changes. Surgical resection is the primary therapeutic modality and usually has a good to excellent outcome.

Purpose: Meningiomas are common, mostly benign, and often asymptomatic. Minimizing surgical adverse events (AE) is essential to maintain a favorable risk-benefit balance. Traditional AE grading systems often failed to account for disabling complications like neurologic deficits, which led to the development of the multidimensional therapy-disability-neurology grade (TDN). This study evaluates risk factors and consequences of AE in meningioma patients using TDN. Methods: Pre- and perioperative factors associated with the occurrence and severity of AE at discharge and follow-up were retrospectively identified in a monocentric cohort of consecutive patients undergoing surgery between 2013 and 2022. Significant variables of the univariable analysis were consequently tested in a multivariable analysis. Statistical analysis to detect the relationship between TDN and clinical outcomes was performed. Results: 367 patients were included with a mean age at surgery of 60.8 years. A total of 95 AE at discharge and 144 AE at follow-up were recorded. Generalized linear models showed a relationship between the modified Rankin Scale on admission, tumor complexity as measured by the Milan Complexity Scale, and preoperative embolization with the frequency of AE at discharge and follow-up. A correlation between TDN, Karnofsky Performance Scale at discharge, and length of hospital stay was observed. Conclusion: The severity of AE as classified according to TDN correlated with the length of hospital stay and functional outcome following meningioma resection in our cohort and may be predicted by specific pre- and perioperative factors.

Background/Objectives: Adverse events (AE) associated with neurosurgical interventions can cause neurological deficits and impaired functional outcomes. The Therapy–Disability–Neurology (TDN) grade classifies AE severity based on treatment requirements, disability, and neurological deficits, but has not been validated in aneurysmal subarachnoid hemorrhage (aSAH). We aimed to validate the TDN grade in predicting functional outcomes and length of hospital stay (LOS) in aSAH patients, treated surgically and/or endovascularly. Methods: We conducted a single-center retrospective cohort study of a prospectively collected database of aSAH patients. Patients were recruited between 2009 and 2022. The TDN grade was retrospectively applied. Primary outcome variables were functional outcomes, assessed using the Glasgow Outcome Scale (GOS, selected for comparability with prior aSAH outcome literature), at discharge and last follow-up, and LOS. Results: We included 355 patients: mean age was 57.2 (12.9 SD) and 235 (66.1%) were female. The TDN grade showed a moderate positive correlation with length of hospital stay (rho = 0.4, p < 0.001). Negative correlations were observed with functional outcomes at discharge (GOS: rho = −0.56, p < 0.0001) and at last follow-up (GOS: rho = −0.58, p < 0.0001). The TDN grade demonstrated good discrimination for unfavorable outcome at last follow-up (AUC = 0.82) and good discrimination for employment status (AUC = 0.71). Patients with AEs stayed 7.63 days longer on average (p < 0.001). Conclusions: The TDN grade predicted hospital stay and functional outcomes in aSAH patients treated surgically and/or endovascularly, demonstrating good discrimination for unfavorable outcomes and employment status. These findings extend the grade’s applicability to both treatment- and disease-related complications and support its potential utility as a standardized tool for prognostication and resource planning. Results should be interpreted in light of the single-center retrospective design and selection bias.

Pyogenic ventriculitis is a rare and potentially fatal infection of the ventricular system. While most reported cases are nosocomial and catheter‐associated, ventriculitis as a complication of community‐acquired bacterial meningitis is uncommon, particularly in adults, and carries a poor prognosis. We report the case of an 82‐year‐old previously healthy and unvaccinated woman who presented with a one‐day history of fever, confusion, and purulent left‐sided otorrhea on a 2‐week background of flu‐like symptoms. Cranial computed tomography was consistent with otogenic meningitis complicated by pneumocephalus, and lumbar puncture confirmed purulent meningitis. Empirical therapy for meningitis with ceftriaxone, amoxicillin, metronidazole, and dexamethasone was initiated, and surgical source control of the otogenic focus was performed. Both blood and cerebrospinal fluid cultures grew Streptococcus pneumoniae with a penicillin minimum inhibitory concentration of < 0.03 mg/L. Serotyping by multiplex PCR with confirmatory Quellung reaction, performed at the Swiss National Reference Center for Invasive Pneumococci, identified Serotype 3. Despite penicillin G monotherapy, fever and impaired consciousness persisted, and repeat imaging revealed meningitis‐associated pyogenic ventriculitis with intraventricular debris. Adjunctive rifampicin and a series of cerebrospinal fluid drainage interventions (lumbar drain followed by external ventricular drain) failed to substantially improve neurological outcome. Antibiotic therapy was continued for 9 weeks, after which the patient was transferred to long‐term institutional care with severe residual neurological impairment. This case illustrates the diagnostic and therapeutic challenges of meningitis‐associated pyogenic ventriculitis in adults and the disproportionate severity of disease caused by Serotype 3 S. pneumoniae , whose unusually thick mucoid capsule promotes immune evasion and the formation of viscous purulent debris that hampers source control. The case is consistent with Swiss surveillance data showing that Serotype 3 remains a leading cause of invasive pneumococcal disease in older adults and serves as a sentinel event highlighting persistent gaps in adult pneumococcal immunization.

Background/Objectives: Unruptured intracranial aneurysms (UIAs) affect 2.3–6.6% of the population. Traditional complication classification systems focus solely on therapeutic interventions, underweighting the burden of neurological deficits in neurovascular patients. This study applied the multidimensional Therapy-Disability-Neurology (TDN) grade to a consecutive cohort of patients treated for UIA in order to characterize the distribution, severity and clinical correlates of adverse events (AEs); the comparison between treatment modalities was a secondary, exploratory objective. Methods: We retrospectively analyzed 296 patients treated for UIA between 2016 and 2025 (microsurgical treatment n = 135, 45.6%; endovascular treatment n = 161, 54.4%). The TDN grade, a three-domain assessment incorporating the therapeutic resources required to treat an AE, functional disability and neurological deficits, was assigned for all AEs occurring during the index hospitalization. AEs were defined as any deviation from the expected post-treatment course, including minor events not usually reported as complications. The primary endpoint was the TDN grade; secondary endpoints included individual AE categories, severe AEs (TDN ≥ 4), functional outcome and length of stay. Results: AEs occurred in 89 patients (30.1%); 37 patients (12.5%) were graded TDN 1 or 2 and 52 (17.6%) TDN 3 to 5, the range corresponding to morbidity as conventionally reported. Four patients (1.4%) died during the index hospitalization or within 30 days of treatment. Median TDN grades were 0 in both groups (microsurgical IQR 0–2; endovascular IQR 0–1; and p = 0.575). The spectrum of AE categories differed between treatment modalities. The TDN grade correlated with GOSE and KPS at discharge and with length of hospital stay (all p < 0.001); length of stay was explained better by the three subgrades together than by the therapy subgrade alone (R² 0.18 vs. 0.13). Treatment modality was not associated with the TDN grade in unadjusted analysis; exploratory adjusted associations with any AE depended on model specification, and no association was found for severe AEs. Conclusions: In this cohort treated for UIA, the TDN grade captured the clinical severity of AEs and may serve as a component of multidimensional outcome assessment in future prospective studies, provided its domains are defined a priori.