Publications by authors named "Schwandt E"

 The endoscopic-assisted supraorbital approach (eSOA) constitutes a minimally invasive strategy for removing anterior skull base meningiomas (ASBM). We present the largest retrospective single-institution and long-term follow-up study of eSOA for ASBM resection, providing further insight regarding indication, surgical considerations, complications, and outcome.  We evaluated data of 176 patients operated on ASBM via the eSOA over 22 years.

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 We evaluated the usefulness of a three-dimensional (3D) interactive atlas to illustrate and teach surgical skull base anatomy in a clinical setting.  A highly detailed atlas of the adult human skull base was created from multiple high-resolution magnetic resonance imaging (MRI) and computed tomography (CT) scans of a healthy Caucasian male. It includes the parcellated and labeled bony skull base, intra- and extracranial vasculature, cranial nerves, cerebrum, cerebellum, and brainstem.

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Aneurysm occlusion rate after clipping is higher than after endovascular treatment. However, a certain percentage of incompletely clipped aneurysms remains. Presurgical selection of the proper aneurysm clips could potentially reduce the rate of incomplete clippings caused by inadequate clip geometry.

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Background: The interoptic triangle (IOT) offers a key access to the contralateral carotid artery's ophthalmic segment (oICA) and its perforating branches (PB), the ophthalmic artery (OA), and the superior hypophyseal artery (SHA). It has been previously reported that the assessment of IOT's size is relevant when attempting approaches to the contralateral oICA. However, previous studies have overseen that, since the oICA is a paramedian structure and a lateralized contralateral approach trajectory is then required, the real access to the oICA is further limited by the approach angle adopted by the surgeon with respect to the IOT's plane.

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Objective: Medially pointing aneurysms of the ophthalmic segment of the internal carotid artery (oICA) represent a neurosurgical challenge. Conventional ipsilateral approaches require internal carotid artery and optic nerve (ON) mobilization as well as anterior clinoidectomy (AC), all associated with increased surgical risk. Contralateral approaches could provide a better exposure of the superomedial aspect of the oICA, ophthalmic artery, and superior hypophyseal artery, sparing AC and internal carotid artery or ON mobilization.

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Osteonecrosis of bone flaps after cranioplasty with autologeous cryo-conserved bone flaps is a common phenomenon. The exact reason for it remains unknown. We present a case of a 67-year old patient who had a bone flap necrosis after elective craniotomy and underwent secondary cranioplasty.

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Ipsilateral approaches remain the standard technique for clipping paraclinoid aneurysms. Surgeons must however be prepared to deal with bony and neural structures restricting accessibility. The application of a contralateral approach has been proposed claiming that some structures in the region can be better exposed from this side.

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Cattle mobility is routinely measured at commercial slaughter facilities. However, the clinical signs and underlying causes of impaired mobility of cattle presented to slaughter facilities are poorly defined. As such, the objectives of this study were 1) to determine the prevalence of impaired mobility in finished cattle using a 4-point mobility scoring system and 2) to observe clinical signs in order to provide clinical diagnoses for this subset of affected cattle.

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Practicing veterinarians (n = 148) who service commercial beef cow-calf herds responded to a survey describing general recommendations made to their clients in terms of vaccine protocol, health, and production practices. Responding veterinarians represented 35 states in the United States and 3 provinces in Canada. More than 50% of responding veterinarians devote over 50% of their practice to service commercial cow-calf producers.

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Strip loin steaks ( = 119) were used to evaluate the association between liver abscess severity and USDA quality grade and meat tenderness and sensory attributes of steaks from finished feedlot cattle. Steaks were used in a 3 × 2 factorial treatment structure using a completely randomized design and were collected at a commercial abattoir located in northwest Texas. All cattle were sourced from a single feedlot and fed a common diet that did not include tylosin phosphate.

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OBJECTIVE The goal of this study was to demonstrate the clinical and technical nuances of a minimally invasive, dorsolateral, tubular approach for partial odontoidectomy, autologous bone augmentation, and temporary C1-2 fixation to treat dens pseudarthrosis. METHODS A cadaveric feasibility study, a 3D virtual reality reconstruction study, and the subsequent application of this approach in 2 clinical cases are reported. Eight procedures were completed in 4 human cadavers.

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Objective: Aneurysm surgery demands precise spatial understanding of the vascular anatomy and its surroundings. We report on a decade of experience planning clipping procedures preoperatively in a virtual reality (VR) workstation and present outcomes with respect to mortality, morbidity, and aneurysm occlusion rate.

Methods: Between 2006 and 2015, the clipping of 115 intracranial aneurysms in 105 patients was preoperatively planned with the Dextroscope, a stereoscopic, patient-specific VR environment.

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Background And Objective: The main difficulties of transpedicular corpectomies are lack of space for vertebral body replacement in the neighborhood of critical structures, the necessity for sacrifice of nerve roots in the thoracic spine. and the extent of hemorrhage due to venous epidural bleeding. We present a modified technique of transpedicular corpectomy by using an endoscopic-assisted microsurgical technique performed through a single posterior approach.

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Crossbred yearling steers ( = 360; 395 ± 33.1 kg initial BW) were used to evaluate the effects of dry-rolled corn (DRC) particle size in diets containing 20% wet distiller's grains plus solubles on feedlot performance, carcass characteristics, and starch digestibility. Steers were used in a randomized complete block design and allocated to 36 pens (9 pens/treatment, with 10 animals/pen).

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Introduction: Three-dimensional (3D) computer graphics are increasingly used to supplement the teaching of anatomy. While most systems consist of a program which produces 3D renderings on a workstation with a standard screen, the Dextrobeam virtual reality VR environment allows the presentation of spatial neuroanatomical models to larger groups of students through a stereoscopic projection system.

Materials And Methods: Second-year medical students (n=169) were randomly allocated to receive a standardised pre-recorded audio lecture detailing the anatomy of the third ventricle accompanied by either a two-dimensional (2D) PowerPoint presentation (n=80) or a 3D animated tour of the third ventricle with the DextroBeam.

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For many years lactate was considered to be a waste product of glycolysis. Data are accumulating that suggest that lactate is an important energy substrate for neurons during activation. In severe traumatic brain injury (TBI) glutamate release and ischemic cerebral blood flow (CBF) are major factors for a mismatch between energy demand and supply and for neuronal cell death.

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Background: Effective hemostasis is mandatory for brain tumor surgery. Microporous polysaccharide hemosphere (MPH) powder, a white powder compounded from potato starch, was recently introduced for surgical and emergency application.

Objective: To evaluate the safety and efficacy of MPHs in brain tumor surgery.

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Purpose: Accurate craniotomy placement is essential for frameless neuronavigation in minimally invasive neurosurgery. A craniotomy using virtual reality (VR) can be as accurate as neuronavigation.

Methods: We prospectively enrolled 48 patients that underwent minimally invasive cranial procedures planned using VR, followed by neuronavigation.

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Background: A surgical technique of posterior calvarial augmentation without the use of plates or screws and avoiding the formation of free bone flaps is described.

Discussion: Three infants with strong occipital flattening successfully underwent the procedure in their first year of life. There were no intra- or postoperative complications; the amelioration of the head shape and the cosmetic results in all three cases were convincing also in the long term.

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Neurocysticercosis is rare in Western Europe and a high degree of physician awareness is necessary for diagnosis. We describe a case of Neurocysticercosis with a single brain lesion acquired in Germany in which only surgical removal and subsequent histological examination allowed diagnosis whereas diagnostic investigation yielded no pathological findings.

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Introduction: Surgery in the temporomesial region is generally performed using a subtemporal, transtemporal, or pterional-transsylvian approach. However, these approaches may lead to approach-related trauma of the temporal lobe and frontotemporal operculum with subsequent postoperative neurological deficits. Iatrogenic traumatisation is especially significant if surgery is performed in the dominant hemisphere.

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Object: The aim of the authors in this study was to introduce a minimally invasive superficial temporal artery to middle cerebral artery (STA-MCA) bypass surgery by the preselection of appropriate donor and recipient branches in a 3D virtual reality setting based on 3-T MR angiography data.

Methods: An STA-MCA anastomosis was performed in each of 5 patients. Before surgery, 3-T MR imaging was performed with 3D magnetization-prepared rapid acquisition gradient echo sequences, and a high-resolution CT 3D dataset was obtained.

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Cavernomas are often small in size and located in difficultly accessible regions. Preoperative identification of the ideal surgical approach as well as the precise intraoperative implementation of the surgical plan are of critical importance for successful surgery. While aiming for minimally invasive surgical techniques and maximally effective cavernoma resection, we envisaged that employing a combination of precise and technically sophisticated virtual reality surgery planning, modern navigation systems with augmented reality features and endoscope-assisted surgical techniques should contribute to achieve this goal.

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Objective: We have developed a highly interactive virtual environment that enables collaborative examination of stereoscopic three-dimensional (3-D) medical imaging data for planning, discussing, or teaching neurosurgical approaches and strategies.

Materials And Methods: The system consists of an interactive console with which the user manipulates 3-D data using hand-held and tracked devices within a 3-D virtual workspace and a stereoscopic projection system. The projection system displays the 3-D data on a large screen while the user is working with it.

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