Post-surgical central nervous system infections (PCNSIs) are a major cause of morbidity, poor functional outcomes and mortality in neurosurgical patients. These infections complicate operations of the CNS or are related to the use of neurosurgical devices or drainage catheters. Gram-negative bacteria, with multiple resistance patterns, are often isolated and these infections are difficult to treat, due to suboptimal antibiotic therapeutic levels in the cerebrospinal fluid (CSF). This is a retrospective study of PCNSIs between 2014 and 2024 in a single center of a tertiary hospital in Thessaloniki, Greece. Out of 2401 neurosurgical procedures, forty-one were complicated by PCNSIs, yielding a total PCNSI prevalence of 1.7%. Thirty-five involved cases with positive CSF culture. The most common interventions were craniotomies for the resection of tumors or other lesions (30.1%). Most cases referred to an EVD infection. Acinetobacter baumannii was the most commonly isolated pathogen (34.1%), followed by coagulase-negative Staphylococcus (22%) and Pseudomonas spp. (14.6%). Colistin and tigecycline were the most prescribed combination regimens. The median time to the first positive CSF culture postoperatively was 11 days (IQR 18 days). Empirical antibiotic treatment was adequate in 26 (63.4%) cases. The mortality rate among these patients was 65.7%. Survivors were significantly younger than non-survivors (p < 0.01) and had a shorter ICU length of stay (p < 0.01). The type of infection, time to infection onset, isolated pathogen, susceptibility to the empirical treatment and Charlson Comorbidity Index did not differ between the two groups. The mortality rate remains high in patients with PCNSIs. An integrated approach including surgical source control, supportive care, combination antimicrobial therapy and subsequent rehabilitation are mandatory to achieve treatment success and neurological convalescence.

Background/Objectives: Navigated transcranial magnetic stimulation (nTMS) enables presurgical motor mapping, while nTMS-seeded diffusion tensor imaging (DTI) delineates the corticospinal tract (CST). We compared cortical and tractography measures between healthy individuals and patients with motor-eloquent brain tumors and between patient hemispheres. Methods: Twenty healthy volunteers and 18 patients underwent first dorsal interosseous (FDI) mapping at 110% resting motor threshold (rMT). Motor map metrics, maximum FDI motor-evoked potential (MEP) amplitude, and nTMS-seeded CST measures were analyzed; hotspot and center-of-gravity (CoG) dispersion were assessed in common space. DTI metrics were available for 13 healthy volunteers and 13 patients. Results: Consistent with previous nTMS literature, patients showed impaired motor performance and suprathreshold corticospinal output, with lower grip strength, maximum FDI MEP amplitude, and map volume than controls. rMT did not differ significantly, indicating that threshold excitability may be unrevealing despite motor system dysfunction. Notably, the contralateral patient hemisphere also differed from controls in grip strength, maximum FDI MEP amplitude, reconstructed CST fiber length, and mean axial diffusivity, while these measures did not differ significantly between the ipsilateral and contralateral patient hemispheres. CoG dispersion was greater in patients, whereas hotspot dispersion was not. Conclusions: The study confirms tumor-associated impairment of motor performance and suprathreshold corticospinal output while identifying two potentially novel observations: abnormalities extending to the apparently unaffected hemisphere and increased heterogeneity of the amplitude-weighted motor map center. Notably, contralateral abnormalities may reflect bilateral network changes or patient-related factors, rather than isolated contralateral CST pathology. Independent healthy controls may therefore provide information not captured by within-patient hemispheric comparisons.