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Purpose: Superficial temporal artery to middle cerebral artery (STA-MCA) direct bypass surgery is the most common surgical procedure to treat moyamoya disease (MMD). Here, we aim to compare the performance of the 3D exoscope in bypass surgery with the gold standard operative microscope. Methods: All direct STA-MCA bypass procedures performed at a single university hospital for MMD between 2015 and 2023 were considered for inclusion. Data were retrospectively collected from patient files and surgical video material. From 2020 onwards, bypass procedures were exclusively performed using a digital three-dimensional exoscope as visualization device. Results were compared with a microsurgical bypass control group (2015–2019). The primary endpoint was defined as total duration of surgery, duration of completing the vascular anastomosis (ischemia time), bypass patency, number of stiches to perform the anastomosis, added stiches after leakage testing of the anastomosis and the Glasgow outcome scale (GOS) at last follow-up as secondary outcome parameter. Results: A total of 16 consecutive moyamoya patients underwent 21 STA-MCA bypass procedures. Thereof, six patients were operated using a microscope and ten patients using an exoscope (ORBEYE® n = 1; AEOS® n = 9). Total duration of surgery was comparable between devices (microscope: 313 min. ± 116 vs. exoscope: 279 min. ± 42; p = 0.647). Ischemia time also proved similar between groups (microscope: 43 min. ± 19 vs. exoscope: 41 min. ± 7; p = 0.701). No differences were noted in bypass patency rates. The number of stiches per anastomosis was similar between visualization devices (microscope: 17 ± 4 vs. exoscope: 17 ± 2; p = 0.887). In contrast, more additional stiches were needed in microscopic anastomoses after leakage testing the bypass (p = 0.035). Conclusion: Taking into account the small sample size, end-to-side bypass surgery for moyamoya disease using a foot switch-operated 3D exoscope was not associated with more complications and led to comparable clinical and radiological results as microscopic bypass surgery. [ABSTRACT FROM AUTHOR]

Background The surgical 3D exoscopes have recently been introduced as an alternative to the surgical microscopes in microneurosurgery. Since the exoscope availability is still limited, it is relevant to know whether even a short-term exoscope training develops the skills needed for performing exoscope-assisted surgeries. Methods Ten participants (six consultants, four residents) performed two laboratory bypass test tasks with a 3D exoscope (Aesculap Aeos®). Six training sessions (6 h) were performed in between (interval of 2–5 weeks) on artifcial models. The participants were divided into two groups: test group (n=6) trained with the exoscope and control group (n=4) with a surgical microscope. The test task was an artifcial end-to-side microsurgical anastomosis model, using 12 interrupted 9–0 sutures and recorded on video. We compared the individual as well as group performance among the test subjects based on suturing time, anastomosis quality, and manual dexterity. Results Altogether, 20 bypass tasks were performed (baseline n=10, follow-up n=10). The median duration decreased by 28 min and 44% in the exoscope training group. The decrease was steeper (29 min, 45%) among the participants with less than 6 years of microneurosurgery experience compared to the more experienced participants (13 min, 24%). After training, the participants with at least 1-year experience of using the exoscope did not improve their task duration. The training with the exoscope led to a greater time reduction than the training with the microscope (44% vs 17%). Conclusions Even short-term training with the exoscope led to marked improvements in exoscope-assisted bypass suturing among novice microneurosurgeons. For the more experienced participants, a plateau in the initial learning curve was reached quickly. A much longer-term efort might be needed to witness further improvement in this user group. [ABSTRACT FROM AUTHOR]

Background: Spinal arteriovenous malformations (AVM) are rare lesions. They may present with intramedullary hemorrhage or edema, often inducing severe neurological deficits. Active treatment of spinal AVMs is challenging even for experienced neurosurgeons. Method: Anticipation of anatomy and AVM angiocharacteristics from preoperative imaging is key for successful treatment. Information gathered from MRI and DSA has to be then matched to intraoperative findings. This is a prerequisite for reasonably safe and structured lesion removal. Conclusion: We provide a structured approach for surgical treatment of spinal AVMs, supplemented by high-resolution video and imaging material. [ABSTRACT FROM AUTHOR]

Background: The far lateral approach has been developed to access lesions at the craniocervical junction and upper cervical spinal canal. Associated morbidity triggered the development of less invasive tailored approaches. Method: In this lateral approach to the craniocervical junction, the occipital condyle is kept intact, vertebral artery manipulation is minimized, and the sigmoid sinus is not skeletonized. A linear incision through skin and muscles and use of an abdominal wall fat graft minimize the risk of cerebrospinal fluid leakage. Conclusions: The exposure provided is sufficient for the majority of tumors in this region and allows for low complication rates. [ABSTRACT FROM AUTHOR]

Background: Alcohol consumption has been reported to deteriorate surgical performance both immediately after consumption as well as on the next day. We studied the early effects of alcohol consumption on microsurgical manual dexterity in a laboratory setting. Method: Six neurosurgeons or neurosurgical residents (all male) performed micro- and macro suturing tasks after consuming variable amounts of alcohol. Each participant drank 0–4 doses of alcohol (14 g ethanol). After a delay of 60–157 min, he performed a macrosurgical and microsurgical task (with a surgical microscope). The tasks consisted of cutting and re-attaching a circular latex flap (diameter: 50 mm macrosuturing, 4 mm microsuturing) with eight interrupted sutures (4–0 multifilament macrosutures, 9–0 monofilament microsutures). We measured the time required to complete the sutures, and the amplitude and the frequency of physiological tremor during the suturing. In addition, we used a four-point ordinal scale to rank the quality of the sutures for each task. Each participant repeated the tasks several times on separate days varying the pre-task alcohol consumption (including one sober task at the end of the data collection). Results: A total of 93 surgical tasks (47 macrosurgical, 46 microsurgical) were performed. The fastest microsurgical suturing (median 11 min 49 s, [interquartile range (IQR) 654 to 761 s]) was recorded after three doses of alcohol (median blood alcohol level 0.32‰). The slowest microsurgical suturing (median 15 min 19 s, [IQR 666 to 1121 s]) was observed after one dose (median blood alcohol level 0‰). The quality of sutures was the worst (mean 0.70 [standard deviation (SD) 0.48] quality points lost) after three doses of alcohol and the best (mean 0.33 [SD 0.52] quality points lost) after four doses (median blood alcohol level 0.44‰). Conclusions: Consuming small amount of alcohol did not deteriorate microsurgical performance in our study. An observed reduction in physiological tremor may partially explain this. [ABSTRACT FROM AUTHOR]

Background: Different versions of the mini-pterional (MPT) approach have been described often with the idea the smaller the better. Attempts to reduce incision and craniotomy size for better cosmetic results should not be performed at the expense of safety. Method: We present our take on the MPT as a balance between size and safety which can be adopted by vascular neurosurgeons in training. The craniotomy stays within the confines of the superior temporal line and is completely covered by temporal muscle after closure. Conclusion: This approach is cosmetically superior while still offering anatomical familiarity and sufficient instrument maneuverability. [ABSTRACT FROM AUTHOR]

Reflecting the first wave COVID-19 pandemic in Central Europe (i.e. March 16th–April 15th, 2020) the neurosurgical community witnessed a general diminution in the incidence of emergency neurosurgical cases, which was impelled by a reduced number of traumatic brain injuries (TBI), spine conditions, and chronic subdural hematomas (CSDH). This appeared to be associated with restrictions imposed on mobility within countries but also to possible delayed patient introduction and interdisciplinary medical counseling. In response to one year of COVID-19 experience, also mapping the third wave of COVID-19 in 2021 (i.e. March 16 to April 15, 2021), we aimed to reevaluate the current prevalence and outcomes for emergency non-elective neurosurgical cases in COVID-19-negative patients across Austria and the Czech Republic. The primary analysis was focused on incidence and 30-day mortality in emergency neurosurgical cases compared to four preceding years (2017–2020). A total of 5077 neurosurgical emergency cases were reviewed. The year 2021 compared to the years 2017–2019 was not significantly related to any increased odds of 30 day mortality in Austria or in the Czech Republic. Recently, there was a significant propensity toward increased incidence rates of emergency non-elective neurosurgical cases during the third COVID-19 pandemic wave in Austria, driven by their lower incidence during the first COVID-19 wave in 2020. Selected neurosurgical conditions commonly associated with traumatic etiologies including TBI, and CSDH roughly reverted to similar incidence rates from the previous non-COVID-19 years. Further resisting the major deleterious effects of the continuing COVID-19 pandemic, it is edifying to notice that the neurosurgical community´s demeanor to the recent third pandemic culmination keeps the very high standards of non-elective neurosurgical care alongside with low periprocedural morbidity. This also reflects the current state of health care quality in the Czech Republic and Austria. [ABSTRACT FROM AUTHOR]

The Helsinki neurosurgical department has been housed for 90 years at the Töölö Hospital located on the western side of the Helsinki peninsula. Aarno Snellman was appointed the first professor of neurosurgery at the Helsinki University in 1947, marking the dawn of neurosurgery in Finland [[10], [16]]. Hospital's operations at Töölö will end in 2023, and neurosurgical services will be transferred to the centralized Meilahti hospital campus of the Helsinki University Hospital, in the new Siltasairaala (Bridge Hospital) currently under construction (Fig. We present a short overview of the history of neurosurgery at Töölö Hospital along current and future perspectives of neurosurgery in Helsinki. [Extracted from the article]

The world currently faces the novel severe acute respiratory syndrome coronavirus 2 pandemic. Little is known about the effects of a pandemic on non-elective neurosurgical practices, which have continued under modified conditions to reduce the spread of COVID-19. This knowledge might be critical for the ongoing second coronavirus wave and potential restrictions on health care. We aimed to determine the incidence and 30-day mortality rate of various non-elective neurosurgical procedures during the COVID-19 pandemic. A retrospective, multi-centre observational cohort study among neurosurgical centres within Austria, the Czech Republic, and Switzerland was performed. Incidence of neurosurgical emergencies and related 30-day mortality rates were determined for a period reflecting the peak pandemic of the first wave in all participating countries (i.e. March 16th–April 15th, 2020), and compared to the same period in prior years (2017, 2018, and 2019). A total of 4,752 emergency neurosurgical cases were reviewed over a 4-year period. In 2020, during the COVID-19 pandemic, there was a general decline in the incidence of non-elective neurosurgical cases, which was driven by a reduced number of traumatic brain injuries, spine conditions, and chronic subdural hematomas. Thirty-day mortality did not significantly increase overall or for any of the conditions examined during the peak of the pandemic. The neurosurgical community in these three European countries observed a decrease in the incidence of some neurosurgical emergencies with 30-day mortality rates comparable to previous years (2017–2019). Lower incidence of neurosurgical cases is likely related to restrictions placed on mobility within countries, but may also involve delayed patient presentation. [ABSTRACT FROM AUTHOR]

We study zeta functions enumerating submodules invariant under a given endomorphism of a finitely generated module over the ring of ( S-)integers of a number field. In particular, we compute explicit formulae involving Dedekind zeta functions and establish meromorphic continuation of these zeta functions to the complex plane. As an application, we show that ideal zeta functions associated with nilpotent Lie algebras of maximal class have abscissa of convergence 2. [ABSTRACT FROM AUTHOR]