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Background:  The present study evaluates the impact of COVID-19 pandemic restrictions during the first lockdown period in spring 2020 on the neurosurgical resident training program, and provides constructive approaches to deal with such situations., Methods:  A concurrent embedded mixed methods design was used. Qualitative data were collected through in-depth interviews from all neurosurgical residents at three university hospitals in Germany. Concurrently, quantitative data of the number of performed surgeries, outpatient visits, and the usage of telemedicine in the period from October 2019 to July 2020 were collected and analyzed accordingly., Results:  During the period of COVID-19 pandemic restrictions in spring 2020, there was a marked reduction in the number of surgeries performed by neurosurgical residents, from an average of 41.26 (median 41) surgeries per month to 25.66 (median 24) per month, representing a decrease of 37.80%. The decrease in the operations was concerning mainly spinal and functional surgery. Outpatient visits were reduced significantly, with a concurrent fivefold increase in the usage of telemedicine. General and pediatric neurosurgery outpatient clinics were the most affected. However, although surgical exposure was reduced during the lockdown phase, neurosurgical residents focused on conducting research and improving theoretical knowledge. Nevertheless, the global uncertainties caused by COVID-19 generated notable psychological stress among some residents., Conclusions:  The COVID-19 pandemic restrictions significantly affected the neurosurgical training program. Innovative solutions need to be developed to increase teaching and research capacities of neurosurgical residents as well as to improve surgical skills by installing surgical skill laboratories or similar constructs., Competing Interests: None declared., (Thieme. All rights reserved.)

Background: Safety, efficacy and efficiency of neurosurgical robots are defined by their design (i.e., framed and non-framed) and procedural workflow (PW) (from image to surgery). The present study describes the quality indicators of three different robots in brain and spine surgery., Methods: This single-centre study enrolled 252 patients over a 10-year period. Safety (complication rate) and efficacy (diagnostic yield, pedicle screw placement) were determined. Predictors of workflow efficiency (e.g., skin-to-skin) were evaluated and compared to conventional techniques (neuronavigation, stereotaxy)., Results: All robots showed excellent reliability (97.5%-100%) with low complication rates (4.5%-5.3%) and high efficacy (94.7%-97.7%). Robotics demonstrated a better time-efficiency than neuronavigation. However, there was no shortening of surgery time compared to conventional stereotaxy. Time-efficiency differed significantly between framed and non-framed workflows., Conclusion: While all neurosurgical robots were reliable, safe and efficacious, there were significant differences in time-efficiency. PWs should be improved to increase the acceptance of robotics in neurosurgery., (© 2021 The Authors. The International Journal of Medical Robotics and Computer Assisted Surgery published by John Wiley & Sons Ltd.)

Background: Medical students show varying clinical practical skills when entering their final year clinical clerkship, which is the final period to acquire and improve practical skills prior to their residency. We developed a one-on-one mentoring program to allow individually tailored teaching of clinical practical skills to support final year students with varying skill sets during their neurosurgical clinical clerkship., Methods: Each participating student (n = 23) was paired with a mentor. At the beginning students were asked about their expectations, teaching preferences and surgical interest. Regular meetings and evaluations of clinical practical skills were scheduled every 2 weeks together with fixed rotations that could be individually adjusted. The one-on-one meetings and evaluations with the mentor gave each student the chance for individually tailored teaching. After completion of the program each student evaluated their experience., Results: The mentoring program was well received by participating students and acquisition or improvement of clinical practical skills was achieved by most students. A varying practical skill level and interest in the field of surgery was seen., Conclusions: A neurosurgical one-on-one mentoring program is well received by final year medical students and allows for individually tailored learning of clinical practical skills.

Background: Training courses in neurosurgery are essential educational elements of residency. Teaching methods vary due to cultural differences, monetary restrictions and infrastructure conditions. Anatomical dissection courses combined with annotated live surgeries performed by senior surgeons have proved to be best accepted by students., Objective: In this technical note, we provide detailed information about the necessary requirements, resources and optimal performance of live surgeries in neurosurgical training courses., Methods and Results: From 2007 to 2012, 12 neurosurgical training courses with live surgeries were organised at the Department of Neurosurgery. Here, we share our experience and report the essential set-up for these courses. Our department organised seven skull base, four cervical spine and one spinal cord stimulation hands-on dissection course with live surgeries. The course structure included lectures, cadaver dissections and live surgeries. The technical set-up included video transmission via an IP-based network with fibreglass backbone between the operating theatre (OR) and lecture room. During surgery, bidirectional discussions offered the participants the ability to interject and ask questions. Important issues included the careful selection of live operated patients with clearly presented pathology for the didactic cases used to demonstrate the technique. A live surgery should include the entire procedure: intraoperative set-up, positioning, anaesthesiological procedures and handling of intraoperative situations., Conclusion: A professionally prepared step-by-step educational program including surgical anatomy, cadaver dissection and live surgeries with online discussion offers a high level of training and enriches both the participants and instructors.

Background: Due to the European Working Time Directive (EWTD) and a new collective agreement for doctors working at University hospitals in 2006 new shift models had to be designed in the Department of Neurosurgery of the University Hospital Tübingen, Germany. The aim of the study was to show the fit of the models regarding the average weekly working time limits (aWTL), the daily maximum of 10-h working time (10-h dWT), and the staff expenditures 3 years after implementation., Methods: The new shift model was implemented in 2008, and hence planning and documentation were done electronically. Adherence to the work schedules was measured, and aWTL adherence rates were compared. The relative number of 10-h dWT violations in 2009 and 2010 was analysed. Staff costs relative to performance before and after implementation were calculated and tested using analysis of variance (ANOVA). Four other departments without alteration of shift models served as a control group in cost trend analysis., Results: In 2010 all doctors in the Department of Neurosurgery were able to stay within the limit of 54 h/week; one doctor without opt-out exceeded the 48 h/week limit (50.1 h/week). The median per capita rate of 10-h dWT violations in 2009 was 20.3 % of all eligible working days and further declined to 10.7 % in 2010 (p < 0.001). Staff costs per case-weight point did not change significantly (2007: 339.88€, 2009: 307.99€, 2010: 322.54€; p = 0.22) in neurosurgery or in the control group (2007: 633.72€, 2009: 637.06€, 2010: 690.30€; p = 0.67)., Conclusions: After implementation of the new shift model, current monitoring and properly matching modifications led to long-term stability in complying with the EWTD regulations without increasing costs for staff expenditures.

Background: Neurosurgery requires a profound knowledge of anatomy and surgical skills. The skull base approach is the crucial step for successful intradural performance. Resident training at experienced institutions must consider this background when educating young neurosurgeons., Methods: From 2006-2008, 223 retrosigmoid approaches for various cerebellopontine angle pathologies have been performed at the Department of Neurosurgery Eberhard-Karls-University, Tübingen. After a minimum time of 6 months assisting, followed by participation of dissection courses and continuous anatomical training, later performing their first approaches under direct supervision of an experienced surgeon, residents perform their first retrosigmoid approaches autonomously in the operating theatre. With this study, we evaluate the surgical morbidity and the time factor related to the educational level of the surgeon., Results: Comparing surgical-related morbidity between approaches performed by experienced neurosurgeons (>100 procedures) and young residents (<20 procedures), we found no significant differences concerning the incidence of cerebrospinal fluid fistulae, sinus lacerations, wound infections, cranioplasty dislocations, or occipital nerve neuromas. Even the mean time for the procedure (positioning, time-to-dural incision) was not significantly longer in the trainee group., Conclusion: Respecting the stepwise educational levels for skull base surgery, including microanatomical studies, educational courses, and expert guidance at surgery, the retrosigmoid approach can be performed by young residents without increased morbidity at experienced institutions.

Modern neurosurgery applies diagnostic imaging, surgical planning and image-guidance with the aim of preservation of neurological function. Thereby, high precision and comprehensive presentation of the acquired multimodal data sets are mandatory for accurate localisation and registration. Morphological and functional information on cortical und subcortical structures should define target and anti-targets and provide the surgeon with an intuitive orientation within the operative field and, thereby, increase the safety of the procedure. Preoperative surgical planning and simulation, as well as intraoperative image-update of the surgical field are expected to further improve the operative result. The functional and specific structural imaging findings for image-guidance need to be validated intraoperatively, e.g. by electrophysiological stimulation, in terms of their sensitivity and specifity. Finally, image-guidance has to prove its impact on overall neurosurgical outcome and patients' quality of live on follow up exams.

The extraordinary improvement of patient outcome after surgical treatment for vestibular schwannomas is relatively recent and has occurred mainly over the last 30 years. The introduction of microsurgical techniques has resulted in increasing degrees of precise anatomical and functional preservation of the facial and cochlear nerves. An expanded microsurgical technique accompanied by continuous electrophysiological monitoring has resulted in marked changes in the primary goals for this surgery. Whereas in the past the primary goal of vestibular schwannoma management was to preserve the patient's life, the objective in vestibular schwannoma treatment today is to preserve neurological function. Long-term follow-up examinations show negligible recurrence rates, indicating that the aim of preservation of nerve function does not limit the completeness of tumor removal with modern neurosurgical techniques. Despite these advances in preserving the anatomical integrity of, for example, the cochlear nerve, losses of function and even deafness may occur postoperatively in some cases. Current biological and technical research in experimental and clinical settings addresses these problems. In this article, the authors report in detail the developments achieved in vestibular schwannoma surgery and the great clinicians to whom these results can be credited.

Background: In the rehabilitation of postoperative facial palsy, physical therapy is of paramount importance. However, in the early rehabilitation phase, voluntary movements are often limited, and thus, the motivation of patients is impacted. In these situations, biofeedback of facial electromyographic (EMG) signals enables the visual representation of the rehabilitation progress, even without apparent facial movements. In the present study, we designed and evaluated a custom-made EMG biofeedback system enabling cost-effective facial rehabilitation. Methods: This prospective study describes a custom-made EMG system, consisting of a microcontroller board and muscle sensors, which was used to record the EMG of frontal and zygomatic facial muscles during frowning and smiling. First, the mean EMG amplitudes and movement onset detection rates (ACC) achieved with the custom-made EMG system were compared with a commercial EMG device in 12 healthy subjects. Subsequently, the custom-made device was applied to 12 patients with and without postoperative facial paresis after neurosurgical intervention. Here, the ratio [laterality index (LI)] between the mean EMG amplitude of the healthy and affected side was calculated and related to the facial function as measured by the House and Brackmann scale (H&B) ranging from 1 (normal) to 6 (total paralysis). Results: In healthy subjects, a good correlation was measured between the mean EMG amplitudes of the custom-made and commercial EMG device for both frontal (r = 0.84, p = 0.001) and zygomatic muscles (r = 0.8, p = 0.002). In patients, the LI of the frontal and zygomatic muscles correlated significantly with the H&B (r = −0.83, p = 0.001 and r = −0.65, p = 0.023). The ACC of the custom-made EMG system varied between 65 and 79% depending on the recorded muscle and cohort. Conclusion: The present study demonstrates a good application potential of our custom-made EMG biofeedback device to detect facial EMG activity in healthy subjects as well as patients with facial palsies. There is a correlation between the electrophysiological measurements and the clinical outcome. Such a device might enable cost-efficient home-based facial EMG biofeedback. However, movement detection accuracy should be improved in future studies to reach ranges of commercial devices. [ABSTRACT FROM AUTHOR]

Background: Vestibular schwannomas (VS) are brain tumors affecting the vestibulocochlear nerve. Thus, VS patients suffer from tinnitus (TN). While the pathophysiology is mainly unclear, there is an increasing interest in repetitive transcranial magnetic stimulation (rTMS) for TN treatment. However, the results have been divergent. In addition to the methodological aspects, the heterogeneity of the patients might affect the outcome. Yet, there is no study evaluating rTMS exclusively in VS-associated tinnitus. Thus, the present pilot study evaluates low-frequency rTMS to the right dorsolateral pre-frontal cortex (DLPFC) in a VS-associated tinnitus. Methods: This prospective pilot study enrolled nine patients with a monoaural VS-associated tinnitus ipsilateral to the tumor. Patients were treated with a 10-day rTMS regime (1 Hz, 100% RMT, 1,200 pulses, right DLPFC). The primary endpoint of the study was the reduction of TN distress (according to the Tinnitus Handicap Inventory, THI). The secondary endpoint was a reduction of TN intensity (according to the Tinnitus Matching Test, TMT) and the evaluation of factors predicting tinnitus outcome (i.e., hearing impairment, TN duration, type of tinnitus). Results: No complications or side effects occurred. There was one drop-out due to a non-responsiveness of the complaint. There was a significant acute effect of rTMS on the THI and TMT. However, there was no significant long-term effect after 4 weeks. While the THI failed to detect any clinically relevant acute effect of rTMS in 56% of the patients, TMT revealed a reduction of TN intensity for more than 20 in 89% and for more than 50 in 56% of the patients. Notably, the acute effect of rTMS was influenced by the TN type and duration. In general, patients with a tonal TN and shorter TN duration showed a better response to the rTMS therapy. Conclusion: The present pilot study is the first one to exclusively evaluate the effect of low-frequency rTMS to the right DLPFC in a VS-associated tinnitus. Our results prove the feasibility and the efficacy of rTMS in this patient cohort. There is a significant acute but a limited long-term effect. In addition, there is evidence that patients with a tonal tinnitus and shorter tinnitus duration might have the strongest benefit. A larger, randomized controlled study is necessary to prove these initial findings. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the clinical value of early post-operative computed tomographic angiography (CTA) after direct extracranial-intracranial (EC-IC) bypass surgery in moyamoya patients. Methods: A retrospective analysis of all adult moyamoya patients treated at our center from 2013 to 2019 with a direct EC-IC bypass was performed. Early post-operative CTA (within 24 h after surgery) was compared with conventional digital subtraction angiography (DSA) 6–12 months after surgery. If available, magnetic resonance time-of-flight angiography (MR-TOF) was evaluated 3 months and 6–12 months post-operatively as well. Imaging results were analyzed and compared with CTA, MR-TOF and DSA, whereat DSA was used as the final and definite modality to decide on bypass patency. Results: A total of 103 direct EC-IC bypasses in 63 moyamoya patients were analyzed. All inclusion criteria were met in 32 patients (53 direct bypasses). In 84.9% the bypass appeared definitively, in 5.7% uncertainly and in 9.4% not patent according to early post-operative CTA. MR-TOF suggested definitive bypass patency in 86.8% 3 months after surgery and in 93.5% 6–12 months after surgery. DSA 6–12 months post-operatively showed a patency in 98.1% of all bypasses. The positive predictive value (to correctly detect an occluded bypass) on post-operative CTA was 12.5%, the negative predictive value (to correctly detect a patent bypass) was 100% with a sensitivity of 100% and a specificity of 86.5%. Conclusion: Early post-operative CTA has a high predictive value to confirm the patency of a bypass. On the other hand, a high false positive rate of (according to CTA) occluded bypasses after direct EC-IC bypass surgery can be seen. This must be considered critically when initiating possible therapeutic measures. [ABSTRACT FROM AUTHOR]

Background: A growing number of patients on anticoagulation or antiplatelet therapy (APT) are planned for elective surgery. The management of perioperative anticoagulation and APT is challenging because it must balance the risk of thromboembolism and bleeding, and specific recommendations for the management of bridging in neurosurgical patients are lacking. We surveyed German neurosurgical centers about their management of perioperative bridging of anticoagulation and APT to provide an overview of the current bridging policy.Method: From April to August 2016, all German neurosurgical departments were invited to participate in the survey. We used SurveyMonkey to compose ten questions and to conduct the survey, and we defined three different approaches for the perioperative management of patients on a preexisting medication: medication will be discontinued (A) with perioperative “bridging” and (B) without perioperative bridging, or (C) medication will be continued perioperatively.Results: Out of 141 respondents, 84 (60%) partially and 77 (55%) fully completed the questionnaire. No defined policy for the perioperative management of anticoagulation and APT was established in 60.7% (51/84) of participating centers. The perioperative management of anticoagulation and APT varied widely among different centers in all items of the questionnaire; for example, in the group of patients at high risk for thromboembolism, acetylsalicylic acid was discontinued in 22%, bridged in 35%, and continued in 35% of centers.Conclusions: There is significant uncertainty regarding the management of perioperative bridging of anticoagulation and APT in neurosurgery because of a lack of prospective and limited retrospective data. [ABSTRACT FROM AUTHOR]

Objective: Nearly two-thirds of patients with vestibular schwannoma (VS) are reporting a significantly impaired quality of life due to tinnitus. VS-associated tinnitus is attributed to an anatomical and physiological damage of the hearing nerve by displacing growth of the tumor. In contrast, the current pathophysiological concept of non-VS tinnitus hypothesizes a maladaptive neuroplasticity of the central nervous system to a (hidden) hearing impairment resulting in a subjective misperception. However, it is unclear whether this concept fits to VS-associated tinnitus. This study aims to determine the clinical predictors of VS-associated tinnitus to ascertain the compatibility of both pathophysiological concepts. Methods: This retrospective study includes a group of 478 neurosurgical patients with unilateral sporadic VS evaluated preoperatively regarding the occurrence of ipsilateral tinnitus depending on different clinical factors, i.e., age, gender, tumor side, tumor size (T1-T4 according to the Hannover classification), and hearing impairment (Gardner- Robertson classification, GR1-5), using a binary logistic regression. Results: 61.8% of patients complain about a preoperative tinnitus. The binary logistic regression analysis identified male gender [OR 1.90 (1.25-2.75); p = 0.002] and hearing impairment GR3 [OR 1.90 (1.08-3.35); p = 0.026] and GR4 [OR 8.21 (2.29-29.50); p = 0.001] as positive predictors. In contrast, patients with large T4 tumors [OR 0.33 (0.13-0.86); p = 0.024] and complete hearing loss GR5 [OR 0.36 (0.15-0.84); p = 0.017] were less likely to develop a tinnitus. Yet, 60% of the patients with good clinical hearing (GR1) and 25% of patients with complete hearing loss (GR5) suffered from tinnitus. Conclusion: These data are good accordance with literature about non-VS tinnitus indicating hearing impairment as main risk factor. In contrast, complete hearing loss appears a negative predictor for tinnitus. For the first time, these findings indicate a non-linear relationship between hearing impairment and tinnitus in unilateral sporadic VS. Our results suggest a similar pathophysiology in VS-associated and non-VS tinnitus. [ABSTRACT FROM AUTHOR]

Background/Study Aims Percutaneous radiofrequency trigeminal rhizotomy (RTR) is a standardized treatment for trigeminal neuralgia, yet it has been associated with serious complications related to the cannulation of the foramen ovale. Some of these complications, such as carotid injury, are potentially lethal. Neuronavigation was recently proposed as a method to increase the procedure's safety. All of the techniques described so far rely on pre- or intraoperative computed tomography scanning. Here we present a simple method based on magnetic resonance imaging (MRI) (radiation free) used to target the foramen ovale under navigation guidance. Patients/Material and Methods We retrospectively analyzed nine patients who had undergone navigated percutaneous RTR based solely on preoperative MRI and compared them with 35 patients who underwent conventional RTR guided by fluoroscopy. We analyzed immediate and late outcome and categorized the results into pain free, > 70% pain reduction, and persistent pain. We also compared groups in terms of the duration of the procedure and the complication rates. Here we describe the navigation method in detail and review the anatomical landmarks for target definition. Results The duration of the surgical procedure was similar in both groups (32.1 in the standard technique versus 34.5 minutes with navigation; p = 0.5157). There was no significant difference between groups regarding pain reduction at the immediate (p = 1.0) or late follow-up (p = 0.6284) time points. Furthermore, no serious complications were observed in the navigated group. Conclusions We present a simple radiation-free method for neuronavigation-assisted percutaneous RTR. This method proved to be safe and effective, and it is especially recommended for young, inexperienced neurosurgeons. [ABSTRACT FROM AUTHOR]

Vestibular schwannoma surgery requires a profound knowledge of anatomy and long-standing experience of surgical skull base techniques, as patients nowadays requests high-quality results from any surgeon. This educes a dilemma for the young neurosurgeon as she/he is at the beginning of a learning curve. The presented series should prove if surgical results of young skull base surgeons are comparable respecting carefully planned educational steps. The first 50 vestibular schwannomas of the first author were retrospectively evaluated concerning morbidity and mortality with an emphasis on functional cranial nerve preservation. The results were embedded in a timeline of educational steps starting with the internship in 1999. Fifty vestibular schwannomas were consecutively operated from July 2007 to January 2010. According to the Hannover Classification, 14% were rated as T1, 18% as T2, 46% as T3, and 21% as T4. The overall facial nerve preservation rate was 96%. Seventy-nine percent of patients with T1–T3 tumours had no facial palsy at all and 15% had an excellent recovery of an initial palsy grade 3 according to the House & Brackman scale within the first 3 months after surgery. Hearing preservation in T1/2 schwannomas was achieved in 66%, in patients with T3 tumours in 56%, and in large T4 tumours in 25%. Three patients suffered a cerebrospinal fluid fistula (6%), and one patient died during the perioperative period due to cardiopulmonary problems (2%). The results demonstrate that with careful established educational plans in skull base surgery, excellent clinical and functional results can be achieved even by young neurosurgeons. [ABSTRACT FROM AUTHOR]

Objective: Erythrocyte sedimentation rate (ESR) is considered as an indicator of inflammatory processes, and it has a prognostic value in the management of specific neoplastic diseases. It also responds to surgical intervention. There is very little data about the alteration of ESR in patients with brain tumors and information on its course after intracranial tumor surgery is completely lacking. Methods: ESR was measured for 10 days in 46 patients (19 women and 27 men; mean age: 49.7 years; range: 13–70 years) who underwent elective craniotomy for tumor microsurgery (70–425 minutes with a mean of 230 minutes) under general anaesthesia. Blood samples were taken on the day before surgery and on each consecutive day after surgery for 10 days. The standard method of measuring ESR was based on the technique first described by Westergren. Results: The mean ESR level on the day before surgery was 8.26 ± 7.27 mm/h after 1 hour and 14.80 ± 10.36 mm/h after 2 hours. After tumor surgery, ESR increased stepwise. The mean peak value of 22.89 ± 13.41 mm/h after the first hour was reached on the third post-operative day. Whereas mean values varied over time, ESR remained increased and did not decline to normal values until the tenth post-operative day. The mean ESR peak value was higher in patients having undergone surgery for intra-axial lesions (31.36 ± 30.43 mm/h on the post-operative day 6) as compared to patients with extra-axial lesions (21.31 ± 12.20 mm/h on the post-operative day 3). Conclusion: ESR is not relevantly increased in patients harboring brain tumors. Because it remains elevated until the tenth post-operative day after uneventful craniotomy and generally responds more slowly than other indicators like C-reactive protein, it is also not suitable for the detection of post-operative infective complications. [ABSTRACT FROM AUTHOR]

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The unusual and rare case of a 6-year-old boy is reported who presented with an arachnoid cyst located in the cerebellopontine angle incorporating an ectopic piece of choroid plexus tissue. A microneurosurgical cyst wall resection was performed and the plexus tissue identified and removed. The rare occurrence of ectopic choroid plexus tissue within cysts of the CNS is discussed.Copyright © 2000 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Deep venous thromboses (DVT) and venous thromboembolisms (VTE) are serious complications after neurosurgical procedures. Hemorrhagic complications of therapeutic anticoagulation on the other hand are also highly dreaded due to the high risk of permanent neurological deficit. Clear guidelines concerning dosage and duration of anticoagulation still do not exist for neurosurgical practice. Over a 10-year episode, patients with postoperative DVT or VTE were retrospectively identified and demographic risk factors as well as routine laboratory coagulation parameters were assessed. The goal was to determine patients at risk for a severe course of thrombosis and complications due to anticoagulation. In total, 173 patients with DVT or VTE were identified. Clinical effect of thrombosis was severe in 32.4% and fatal in 5.8% of all patients. Spinal surgery was associated with a higher risk of major or fatal outcome of thrombosis as compared to cranial procedures (fatal: 12.1 vs. 4.3%, p = 0.035). Elevated partial thromboplastin time, low platelet levels and low quick on diagnosis of thrombosis were associated with a fatal clinical course (p = 0.02, 0.04 and 0.02 respectively). Severe hemorrhagic complications on the other hand occurred in 6.6%, 0.6% were fatal. D-dimer did not predict the course of DVT/VTE but higher levels of Ddimer on day 3 after diagnosis of DVT/VTE were associated with a higher risk of severe bleeding complications (cutoff 4.95 µg/mL). Partial thromboplastin time after initiation of anticoagulation was not associated with hemorrhagic complications and might thus be not helpful to determine the risk of bleeding complications during the early postoperative phase. D-dimer might be of additional use to detect early bleeding complications. [ABSTRACT FROM AUTHOR]

At our institution, patients undergoing neurosurgical procedures in the posterior cranial fossa are placed either in the semisitting or in the supine position. The major risk of the semisitting positioning is a venous air embolism (VAE), which may, however, also occur in the supine position. In a prospective single-center study with 137 patients, we evaluated the occurrence of VAEs in patients in the supine and in the semisitting position during the period from January 2014 until April 2015. All patients were monitored for VAE by the use of a transesophageal echocardiography (TEE). In total, 50% of the patients experienced a VAE (56% of these patients underwent surgery in the semisitting and 11% in the supine position). In total, 86% of the VAEs were detected by the use of a TEE and did not lead to any changes in the end-expiratory CO 2. We only observed VAEs with a decrease in end-expiratory CO 2 in the semisitting position. However, none of the patients had any hemodynamic changes due to the VAE. The semisitting position with TEE monitoring and a standardized protocol is a safe and advantageous technique, taking account of a significant rate of VAEs. VAEs also occur in the supine position, but less frequently. [ABSTRACT FROM AUTHOR]

Abstract: Intraoperative electrical stimulation in awake patients is a seminal technique during brain surgery allowing one to infer the function of brain areas by temporary inactivation. Using this technique, we found that inactivation of the middle portion of the superior temporal gyrus (STG) leads to disturbed serial exploratory visual search. The data supplement recent findings by Ellison et al. [Ellison, A., Schindler, I., Pattison, L. L., & Milner, A. D. (2004). An exploration of the role of the superior temporal gyrus in visual search and spatial perception using TMS. Brain, 127, 2307–2315] using repetitive transcranial magnetic stimulation over the STG in healthy subjects. Our data demonstrate that the STG is integral to human exploration behaviour and challenge the traditional view that only the right posterior parietal cortex is involved in the mediation of visual search processes. [Copyright &y& Elsevier]

Objective To show that the combined use of intraoperative high-field MRI (iMRI) and electrophysiologic monitoring (IOM) is feasible, safe, and beneficial for patients. Methods The setup, surgical, imaging, and clinical results of 110 patients with eloquent intracranial lesions with the combined use of 1.5T iMRI and IOM were analyzed. Results 187 iMRI scans were performed with IOM needles in place, resulting in a total experience of using >4000 electrodes in the iMRI. No complication (ferromagnetic or relevant heating/burning of skin) was caused by the combined use of both technologies. Surgically induced severe postoperative sensorimotor deficits were seen in 11.8%. The surgeon's estimation of a “complete resection” proved to be true postoperatively in 90.3%. If the resection was stopped due to worsening of IOM, postoperative MRI revealed residual disease to be located in direct vicinity of eloquence in 27 of 28 cases, but not in other parts of the resection cavity. Of these patients, only 7% (2 of 28) had relevant new deficits after 3 months. In 82 patients (74.5%), the resection was continued after the iMRI scan, whereas in only 18 patients (16.4%) the resection was already completed at this point. Conclusion The combined use of IOM and 1.5T iMRI is feasible and safe. The complementary use of both technologies might result in more radical resections at comparable surgically induced neurologic deficits. If available and indicated, the combined use of IOM and iMRI should be performed on a routine basis. [ABSTRACT FROM AUTHOR]

Objective: To analyze the actual risk for patients with a patent foramen ovale (PFO) to experience a clinically relevant venous air embolism (VAE) during surgery performed in the semisitting position. Methods: All procedures were performed between January 2008 and December 2009, under general anesthesia and in the semisitting position. Transesophageal echocardiography (TEE) and capnometry were used intraoperatively to monitor for air bubbles in the venous system. Results: Of 200 consecutive patients who all were operated on in the semisitting position, 52 patients (26%) had a diagnosis of PFO. Rates of VAE in patients were graded as follows: grade 0 (no air bubbles visible, no air embolism), 23 patients (44.2%); grade I (air bubbles on TEE), 22 patients (42.3%); grade II (air bubbles on TEE with decrease of end-tidal carbon dioxide [ETCO2] ≤3 mm Hg), 2 patients (3.8%); grade III, air bubbles on TEE with decrease of ETCO2 >3 mm Hg, 4 patients (7.7%); grade IV, air bubbles on TEE with decrease of ETCO2 >3 mm Hg and decrease of mean arterial pressure ≥20% or increase of heart rate ≥40% (or both), 1 patient (1.9%); and grade V, VAE causing arrhythmia with hemodynamic instability requiring cardiopulmonary resuscitation, 0 patients (0%). There were no deaths in this series, and no new or unexplained, mild or severe neurologic deficits were caused by a VAE. Conclusions: Under standardized anesthesia and neurosurgical protocols, patients with a PFO can be operated on safely in the semisitting position. [Copyright &y& Elsevier]

Background: Intraoperative neuromonitoring has been established as one of the methods by which modern neurosurgery can improve surgical results while reducing morbidity. Despite routine use of intraoperative facial nerve (FN) monitoring, FN injury still is a complication of major concern due to severe negative impact on patient′s quality of life. Methods: Through searches of PubMed, we provided a systematic review of the current literature up to February, 2011, emphasizing all respects of FN monitoring for cerebellopontine angle and skull base tumor surgery from description to current success on function prediction of standard and emerging monitoring techniques. Results: Currently, standard monitoring techniques comprise direct electrical stimulation (DES), free-running electromyography (EMG), and facial motor evoked potential (FMEP). We included 62 studies on function prediction by investigating DES (43 studies), free-running EMG (13 studies), and FMEP (6 studies) criteria. DES mostly evaluated postoperative function by using absolute amplitude, stimulation threshold, and proximal-to-distal amplitude ratio, whereas free-running EMG used the train-time criterion. The prognostic significance of FMEP was assessed with the final-to-baseline amplitude ratio, as well as the event-to-baseline amplitude ratio and waveform complexity. Conclusions: Although there is a general agreement on the satisfactory functional prediction of different electrophysiological criteria, the lack of standardization in electrode montage and stimulation parameters precludes a definite conclusion regarding the best method. Moreover, studies emphasizing comparison between criteria or even multimodal monitoring and its impact on FN anatomical and functional preservation are still lacking in the literature. [ABSTRACT FROM AUTHOR]