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J Rachinger

Publications and source records attributed to J Rachinger.

6 recordsLinked to original sources
PubMed2006

Intradural-extramedullary cavernous hemangioma of the left motor root C7--case report and update of the literature.

OBJECTIVE: Intradural-extramedullary cavernomas of the spine are rare lesions with only 21 published cases to date. Due to their rareness and special characteristics diagnosis often is difficult. We report on an additional case of an intradural-extramedullary cavernoma of the spine. PATIENT: A 56-year-old male presented with left shoulder pain and acute onset of pain affecting the whole spinal column two weeks prior to admission. There were no motor deficits, but a hypesthesia corresponding to the right distal C8-dermatome. MRI revealed an intradural-extramedullary, expansive lesion at the level of C6 with a hyperintense appearance in both T (1)- and T (2)-weighted images. Neither a hemosiderin rim nor contrast enhancement was visible. RESULTS: During surgery a hematoma and a reddish, berry-like tumor adherent to the left motor root C7 were removed. There were no new neurological deficits, and shoulder and back pain resolved within a few weeks after surgery. Histopathologically a cavernous hemangioma was diagnosed. CONCLUSIONS: The patient's symptoms were caused both by direct nerve compression and by spinal hemorrhage, most likely spinal SAH. As there was no characteristic hemosiderin rim and due to the hyperintense appearance in T (1)- and T (2)-weighted MR scans, a radiological diagnosis of hemorrhage and classification of the lesion was difficult. Despite their rareness, in patients with signs of spontaneous, spinal SAH and/or nerve compression syndromes cavernous hemangiomas have to be considered as a potential cause.

Hemangioma, Cavernous, Central Nervous System↗
PubMed2005

An automated robotic approach with redundant navigation for minimal invasive extended transsphenoidal skull base surgery.

BACKGROUND: The aim of this work was to determine the feasibility of a robotic-assisted and fully automated approach to the sphenoid sinus. An image-guided robotic system was designed to address potential human errors in performing transsphenoidal sinus surgery by combining the reproducible accuracy of a robotic system with standard computer navigation. METHODS: A six-degrees of freedom robotic assistance system and an opto-electrical navigation system were combined for image-guided assistance with redundantly controlled robotics. Newly designed endoscopic instruments for robotic surgery have been developed and are described. Telemanipulatory, as well as fully automated procedures, were tested on cadaveric heads as part of a preclinical trial. RESULTS: A fully automated sphenoidotomy as well as a telemanipulatory sphenoidectomy were performed successfully on cadaveric heads. Intraoperative performance, accuracy assessment studies, as well as possible sources of stereotactic offsets are described. The mean measured robotic reproducibility accuracy was 0.056 mm (range: 0.02 - 0.14 mm) and the mean overall navigated robotic accuracy, including all transformation and registration errors was 1.53 mm (range: 1.13 - 1.89 mm) respectively. CONCLUSION: A system for robot-guided surgery in combination with redundant navigational control was developed. It allows highly accurate maneuvers, performed either in a telemanipulation mode as master-slave system or in a fully automated fashion. A sphenoidectomy on cadaveric heads was performed in both telemanipulation and fully automated modes. The overall intraoperative accuracy was in the range of the resolution of the CT images and stereotactic offsets were caused mainly due to deflections of the endoscopic operating instrument.

Cadaver↗
PubMed2004

Adaptation of a hexapod-based robotic system for extended endoscope-assisted transsphenoidal skull base surgery.

OBJECTIVE: To adapt a hexapod-based robotic system for use in extended endoscope-assisted transsphenoidal skull base surgery. METHODS: A robotic system (Evolution 1, Universal Robot Systems, Schwerin, Germany) based on a hexapod design with an attached seventh axis is used as instrument holder. The instrument interface is operated via a joystick control. An endoscope is applied to the instrument interface, which is tracked by a navigation system (Stealth, Medtronic, USA). RESULTS: The instrument holder was modified so that it could be applied in transsphenoidal surgery. Furthermore, translation and pivoting movements of the system were implemented, also a quick change between microscope and robotic-controlled endoscope was made possible. After extensive phantom testing two patients with large invasive pituitary adenomas were operated on using the robotic endoscope assistance during transsphenoidal surgery. The robotic assistance allowed the use of two additional instruments under endoscopic view. For example, drilling, suctioning, application of punches, as well as microsurgical tumor removal could be performed under endoscopic view. CONCLUSION: A robotic system could be adapted for use in endoscope-assisted transsphenoidal skull base surgery allowing simultaneous use of two instruments under endoscopic view. This opens new possibilities to extend transsphenoidal skull base surgery.

Adenoma↗
PubMed2001

Recurrence of a cerebral arteriovenous malformation after surgical excision.

Complete resection of a cerebral arteriovenous malformation (AVM) should eliminate the future risk of an associated intracranial bleeding. Because total removal of an AVM may be difficult to assess at the time of surgery, postoperative angiography has become the accepted standard for documenting that complete removal has been achieved. However, even angiographically confirmed excision of an AVM does not completely exclude the possibility of rebleeding. Regrowth of an AVM with subsequent haemorrhage has been documented in children and is attributed to forces acting on the immature vasculature. The authors report the case of a 21-year-old man whose AVM recurred 5 years after angiographically proven complete excision. According to the presented case, the authors emphasise that, even in adults, angiographic documentation of total removal does not always eliminate the risk of reformation of an AVM.

Adult↗
PubMed2000

Factors influencing the application accuracy of neuronavigation systems.

OBJECTIVE: The overall accuracy of neuronavigation systems may be influenced by (1) the technical accuracy, (2) the registration process, (3) voxel size and/or distortion of image data and (4) intraoperative events. The aim of this study was to test the influence of the registration and imaging modality on the accuracy. METHODS: A plexiglas phantom with 32 rods was taken for navigation targeting. Sixteen fiducials were attached to the surface of the phantom forming two different attachment patterns (clustered vs. diffusely scattered). This model was scanned by MRI and CT (1-mm slices). Registration was performed using different numbers and attachment patterns of the fiducials. Using CT or MRI, the localization error was measured in image space as the Euclidean distance between targets defined in image space and those detected in the physical space. Accuracy was measured with two commercial systems, the Zeiss MKM and the StealthStation. RESULTS: The mean localization error varied between 1.59 +/- 0.29 mm (MKM, 8 scattered fiducials, CT scanning) and 3.86 +/- 2.19 mm (MKM, 4 clustered fiducials, MRI). The worst localization error was 9.5 mm (MKM). In case of an optimal registration, the 95th percentile for the localization error was 2.2 (MKM) and 2.75 mm (StealthStation). The imaging modality has only minor influence on the localization error, with CT increasing accuracy minimally. Both the fiducial number and the attachment pattern critically influence the localization error: 8 fiducials and a generalized attachment pattern increase the accuracy significantly. No correlation between the calculated registration accuracy and the measured localization accuracy was found. CONCLUSION: The application accuracy of different neuronavigation systems critically depends on the registration. The calculated registration accuracy provided by the system does not correspond to the localization error found in reality. The accuracy of frameless neuronavigation systems is comparable to that of classical frame-based stereotactic devices.

Magnetic Resonance Imaging↗