Ralf A Kockro

Klinik Hirslanden · Center for Microneurosurgery

Background Upper-cervical meningioma represents a large portion of intradural extramedullary tumors that occur in the cervical spinal canal. Most of them are located ventrally or ventrolateral to the spinal cord. Reaching lesions at this location surgically is technically challenging. Objectives The ideal approach to ventrally located upper-cerv...

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. The aim of the present study was to assess wheth...

Objective We evaluated the usefulness of a three-dimensional (3D) interactive atlas to illustrate and teach surgical skull base anatomy in a clinical setting. Study Design 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 C...

Objectives: Approaches to the hypothalamus and anterior third ventricle are variable. We present a technical note on access of the hypothalamus using the trans-lamina terminalis approach by supraorbital craniotomy in a patient who had a hypothalamic cavernoma and presented to us with recurrent hemorrhage. Patients and methods: The trans-lamina ter...

Objectives: Approaches to the hypothalamus and anterior third ventricle are variable. We present a technical note on access of the hypothalamus using the trans-lamina terminalis approach by supraorbital craniotomy in a patient who had a hypothalamic cavernoma and presented to us with recurrent hemorrhage. Patients and methods: The trans-lamina term...

The Dextroscope is a surgical planning system that takes advantage of some of the key aspects of virtual reality to maximize the potential of multimodal patient data: two-handed input in 3D and stereoscopic volume-rendering visualization of 3D data. 3D patient models are manipulated in 3D by the surgeon in an easy, intuitive, and flexible manner, w...

Objective: Aneurysm surgery demands precise spatial understanding of the vascular anatomy and its surroundings. We report on a decade of experience planning clipping procedures pre-­‐operatively in a virtual reality (VR) workstation and present outcomes with respect to mortality, morbidity and aneurysm occlusion rate. Methods: The clipping of 115...

Objective: Aneurysm surgery demands precise spatial understanding of the vascular anatomy and its surroundings. We report on a decade of experience planning clipping procedures pre-operatively in a virtual reality (VR) workstation and present outcomes with respect to mortality, morbidity and aneurysm occlusion rate. Methods: Between 2006 and 201...

Background: Glioblastoma resection guided by 5-aminolevulinic acid (5-ALA) fluorescence and intraoperative magnetic resonance imaging (iMRI) may improve surgical results and prolong survival. Objective: To evaluate 5-ALA fluorescence combined with subsequent low-field iMRI for resection control in glioblastoma surgery. Methods: Fourteen patien...

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...

Improvements in image guidance, endoscopy, and instruments, have significantly advanced "keyhole" neurosurgery. We describe the concept and technique of the supraorbital keyhole approach. The supraorbital keyhole approach is performed through an eyebrow skin incision. Image guidance may be used to define the optimal surgical trajectory. A limited s...

To review our surgical experience in minimally invasive transcranial endoscope-assisted microsurgical treatment of intracranial aneurysms, using the supraorbital keyhole craniotomy. The supraorbital keyhole approach was performed through an eyebrow skin incision in 793 cases for treatment of 989 intracranial aneurysms. Of patients, 474 were operate...

OBJECT: The supraorbital approach through an eyebrow incision offers the opportunity to access a wide variety of lesions of the anterior, middle, and even the posterior fossa. The minimally invasive keyhole craniotomy limits brain exploration and retraction and offers the potential for improved surgical outcomes and reduced approach-related complic...

The spatial complexity of highly vulnerable structures makes surgical resection of brainstem cavernomas (BSC) a challenging procedure. Diffusion tensor imaging (DTI) allows for the visualization of white matter tracts and enables a better understanding of the anatomical location of corticospinal and sensory tracts before and after surgery.We invest...

The management of unruptured and asymptomatic intracranial aneurysms remains controversial. Since aneurysmal hemorrhage carries a high risk of mortality and morbidity it is essential to estimate the probability of aneurysm rupture in each individual case in order to decide whether treatment should be recommended. The likelihood that a given aneurys...

Objective: The concept and surgical technique of endoscope-assisted keyhole surgery in treating lesions of the anterior fossa and central skull base is described in this article. Methods: Between 2007 and 2011, 362 patients underwent endoscope-assisted keyhole surgery utilizing the supraorbital subfrontal (SOR, n = 218), mini-pterional frontotempor...

Background An accurate and rapid anatomical localization of implanted subdural electrodes is essential in the invasive diagnostic process for epilepsy surgery. Objective To demonstrate our experience with a three-dimensional (3D) virtual reality simulation software (Dextroscope®, Bracco Imaging, Milano, Italy) in the postoperative localization of s...

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Background: In the past decade, surgery planning has changed significantly. The main reason is the improvements in computer graphical rendering power and display technology, which turned the plain graphics of the mid-1990s into interactive stereoscopic objects. Objective: To report our experiences with 2 virtual reality systems used for planning...

Background: In the past 2 decades, intraoperative navigation technology has changed preoperative and intraoperative strategies and methodology tremendously. Objective: To report our first experiences with a stereoscopic navigation system based on multimodality-derived, patient-specific 3-dimensional (3-D) information displayed on a stereoscopic...

Aim: An accurate and rapid anatomical localization of implanted subdural electrodes is essential in the invasive diagnostic process for epilepsy surgery. The aim of this study is to demonstrate our experience with a three-dimensional (3-D) virtual reality simulation software (Dextroscope®) in the postoperative localization of subdural electrodes im...

Background and importance The suprasellar and hypothalamic/chiasmatic regions can harbor a broad range of pathologic conditions, both neoplastic and nonneoplastic; however, malignant gliomas are extremely rare in those regions. Clinical presentations Patient 1 was a 70 year-old man with weight loss and rapidly progressive visual impairment. A mass...

Objective: Improvements in preoperative diagnostic imaging as well as in microsurgical techniques significantly advanced the development of transcranial neurosurgery, allowing the treatment of complicated diseases through smaller and more specific approaches. Methods: In this article, authors overviewed their experience in transcranial endoscope...

Symptomatic chronic subdural hematoma (scSDH) is one of the most frequent diseases in neurosurgical practice, and its incidence is increasing. However, treatment modalities are still controversial. The aim of this retrospective single-center study is to compare for the first time two surgical methods in the treatment of subdural hematoma that have...

Accurate craniotomy placement is essential for frameless neuronavigation in minimally invasive neurosurgery. A craniotomy using virtual reality (VR) can be as accurate as neuronavigation. We prospectively enrolled 48 patients that underwent minimally invasive cranial procedures planned using VR, followed by neuronavigation. First, craniotomies were...

A 16-year-old boy presented with an unusual case of a supratentorial, extraaxial small round blue cell tumor of the central nervous system, which was most likely a primitive neuroectodermal tumor (PNET). Preoperative computed tomography and magnetic resonance imaging showed a large multistage hematoma in the left central region. Intraoperatively, a...

Introduction Cavernous malformations of the brainstem differ from those in other locations in terms of clinical picture, bleeding rate, and operability. A typical feature of brainstem cavernous malformations is their significant clinical impact. Frequently, even small lesions or relatively small hematomas may cause severe neurological deficits due...

Three-dimensional ultrasound (US) technology is supposed to help combat some of the orientation difficulties inherent to two-dimensional US. Contemporary navigation solutions combine reconstructed 3D US images with common navigation images and support orientation. New real-time 3D US (without neuronavigation) is more time effective, but whether it...

Puncture of the ganglion Gasseri through the foramen ovale and subsequent thermocoagulation, balloon compression, or glycerin injection is a well-established technique to treat trigeminal neuralgia. However, direct puncture of the foramen is sometimes difficult. Here, the authors present a simple technique of improved biplane fluoroscopic control f...

Progress in medical imaging and refined methods of surgery planning, such as Virtual Reality (VR), call for an investigation of the acquisition of three-dimensional (3-D) anatomical knowledge as a crucial goal of medical education. This study compared the efficacy to reconstruct a 3-D arrangement of objects that was either presented as a real model...

We developed an augmented reality system that enables intraoperative image guidance by using 3-dimensional (3D) graphics overlaid on a video stream. We call this system DEX-Ray and report on its development and the initial intraoperative experience in 12 cases. DEX-Ray consists of a tracked handheld probe that integrates a lipstick-size video camer...

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...

We have developed an interactive virtual model of the temporal bone for the training and teaching of cranial base surgery. The virtual model was based on the tomographic data of the Visible Human Project. The male Visible Human's computed tomographic data were volumetrically reconstructed as virtual bone tissue, and the individual photographic slic...

Between January 2004 and June 2007 we conducted a retrospective analysis to assess post-operative complications related to endoscopic pituitary surgery in a series of 150 patients. Patients were treated with an endoscopic endonasal transsphenoidal approach to the sellar region for removal of pathological sellar and suprasellar lesions. We analysed...

To evaluate the feasibility of surgical planning using a virtual reality platform workstation in the treatment of cerebral arterio-venous malformations (AVMs) Patient-specific data of multiple imaging modalities were co-registered, fused and displayed as a 3D stereoscopic object on the Dextroscope, a virtual reality surgical planning platform. This...

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 cave...

The direct endonasal or transoral transclival approaches to the skull base permit effective minimally invasive surgery along the clivus region. Developing consistently effective techniques to prevent cerebrospinal fluid (CSF) leaks and their consequences (infections and healing processes with long and complicated recoveries) remains a major challen...

The authors have developed a stereotactic device for use in rabbits that uses the plane at the base of the mandible combined with cranial sutures as an anatomical reference. The device was developed for a study designed to evaluate catheters for infection prophylaxis, and this required the implantation of silicone catheters along a reproducible tra...

The authors report on their experience with a 3D virtual reality system for planning minimally invasive neurosurgical procedures. Between October 2002 and April 2006, the authors used the Dextroscope (Volume Interactions, Ltd.) to plan neurosurgical procedures in 106 patients, including 100 with intracranial and 6 with spinal lesions. The planning...

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. The system consists of an interactive console with which the user manipulates 3-D data using hand-held and track...

For stent graft selection in the treatment of abdominal aortic aneurysms (AAA) anatomic considerations are important. They determine GO/NO-GO of the treatment and help customize the stent. Current systems for AAA stent insertion planning based on pre-operative CT and MR of the patient do not provide an intuitive interface to view the resulting meas...

One embodiment of the present invention includes a system comprising an input interface having at least 3 degrees of spatial freedom for input control; and a diffusion tensor imaging (DTI) module operable with the input interface having at least 3 degrees of spatial freedom. In one embodiment, the DTI module is operable to compute fiber bundles. Th...

Augmented reality (AR) on microscope is making good progress[1]. We present a video-based AR-enhanced microscope system for neurosurgical navigation. With this system, computer-generatedimages from the pre-operative image data can be combined with real-time video of surgical field duringsurgery. The novelties of the system lie in the fact that mult...

A system to visualize and manage the space covered by ultrasound acquisition is presented. This system, SonoDEX, uses a conventional ID transducer array ultrasound probe to create and visualize virtual 3D images in real-time, which can be frozen and reconstructed into volumetric images and then co-registered and fused with pre-segmented volumetric...

A system and method for controlling the scaling of a 3D computer model in a 3D display system include activating a zoom mode, selecting a model zoom point and setting a zoom scale factor are presented. In exemplary embodiments according to the present invention, a system, in response to the selected model zoom point and the set scale factor, can im...

This paper describes an interaction system called the DextroBeam designed for manipulating objects in 3D space while looking at a 3D stereoscopic display located in front of the user. Three-dimensional interaction is two-handed and is achieved by means of a stylus with a single button or switch. We have been planning several neurosurgical cases wit...

A system is presented permitting a user to interact a three-dimensional model. The system displays an image of the model in a workspace. A processor of the system defines (i) a virtual plane intersecting with the displayed model and (ii) a correspondence between the virtual plane and a surface. The user positions a tool on the surface to select a p...

. We present a multimodal volume-based pre-operative surgical planning system developed around the KRDL Virtual Workbench, a mirror-based Virtual Reality system for precise work with 3D data. The planning system is being developed in collaboration with the Singapore General Hospital (SGH), and is undergoing clinical evaluation at SGH and Tan Tock S...

Infection continues to be one of the major complications of cerebrospinal fluid (CSF) shunting procedures, and is caused mainly by skin-derived bacteria. Production of an extracellular biofilm plays an important role in the pathogenesis of shunt-associated infections by protecting bacteria from immune mechanisms and antibiotics. So far, removal of...

OBJECTIVE: To report our experience with preoperative neurosurgical planning in our stereoscopic virtual reality environment for 21 patients with intra- and extra-axial brain tumors and vascular malformations. METHODS: A neurosurgical planning system called VIVIAN (V irtual I ntracranial Vi sualization a nd N avigation) was developed for the Dextro...

OBJECTIVE To report our experience with preoperative neurosurgical planning in our stereoscopic virtual reality environment for 21 patients with intra- and extra-axial brain tumors and vascular malformations. METHODS A neurosurgical planning system called VIVIAN (V irtual I ntracranial Vi sualization a nd N avigation) was developed for the Dextros...

Based on the KRDL Virtual Workbench, we present a neurosurgical planning system called VIVIAN (Virtual Intracranial Visualization And Navigation). This VR environment allows for fast and intuitive interaction with three-dimensional multimodal (MRI, MRA, MRV, CT) patient specific data-sets. The user reaches behind a mirror into a 3D workspace where...

We have developed a 3D/2D paradigm of interaction that combines manipulation of precise 3D volumetric data with unambiguous widget interaction. Precise 3D interaction is ensured by a combination of resting the lower arms on an armrest and pivoting the hands around the wrist. Unambiguous 2D interaction is achieved by providing passive haptic feedbac...

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We present a multimodal volume-based pre-operative surgical planning system developed around the KRDL Virtual Workbench, a mirror-based Virtual Reality system for precise work with 3D data. The planning system is being developed in collaboration with the Singapore General Hospital (SGH), and is undergoing clinical evaluation at SGH and Tan Tock Sen...

We present a virtual reality application to neurosurgical pre-operative planning which is undergoing clinical evaluation at the Singapore General Hospital. The application, based on the ISS Virtual Workbench, lets the neurosurgeon study the brain pathology, blood vessels, skull and the surrounding tissue using real-time volumetric rendering of the...

Purpose In 24,436 shunt procedures collected from 108 papers we found A mean infection rate of 8.7% with 5.8% in the 1990's. A few series with extreme low infection rates were not compatible with the kind of conditions generally encountered. After discovering the importance of the basic mechanisms of the "plastic infection" (adhesion, slime) surfac...