Biomedical subjects

J Weisenberger

Publications and source records attributed to J Weisenberger.

9 recordsLinked to original sources

PubMed1999

Frameless stereotaxy with scalp-applied fiducial markers for brain biopsy procedures: experience in 218 cases.

OBJECT: The goal of this study was to develop and assess the use and limitations of performing brain biopsy procedures by using image-guided surgical navigation systems (SNSs; that is, frameless stereotactic systems) with scalp-applied fiducial markers. METHODS: Two hundred eighteen percutaneous brain biopsies were performed in 213 patients by using a frameless stereotactic SNS that operated with either sonic or optical digitizer technology and scalp-applied fiducial markers for the purpose of registering image space with operating room space. Common neurosurgical and stereotactic instrumentation was adapted for use with a localizing wand, and recently developed target and trajectory guidance software was used. Eight (3.7%) of the 218 biopsy specimens were nondiagnostic; five of these (2.4%) were obtained during procedures in 208 supratentorial lesions and three were obtained during procedures in 10 infratentorial lesions (30%; p < 0.001). Complications related to the biopsy procedure occurred in eight patients (seven of whom had supratentorial lesions and one of whom had an infratentorial lesion, p > 0.25). Five complications were intracerebral hemorrhages (two of which required craniotomy), two were infections, and one was wound breakdown after instillation of intratumoral carmustine following biopsy. There were only three cases of sustained morbidity, and there were two deaths and one delayed deterioration due to disease progression. Two surgeons performed the majority of the procedures (193 cases). The three surgeons who performed more than 10 biopsies had complication rates lower than 5%, whereas two of the remaining four surgeons had complication rates greater than 10% (p = 0.15). Twenty-three additional procedures were performed in conjunction with the biopsies: nine brachytherapies; five computer-assisted endoscopies; four cyst aspirations; two instillations of carmustine; two placements of Ommaya reservoirs; and one craniotomy. CONCLUSIONS: Brain biopsy procedures in which guidance is provided by a frameless stereotactic SNS with scalp-applied fiducial markers represents a safe and effective alternative to frame-based stereotactic procedures for supratentorial lesions. There were comparable low rates of morbidity and a high degree of diagnostic success. Strategies for performing posterior fossa biopsies are suggested.

Adolescent↗

PubMed1999

Predictors of axillary lymph node metastasis in T1 breast carcinoma.

This study was designed to determine the predictors of axillary lymph node metastasis in T1a (< or =0.5 cm), T1b (>0.5 cm and < or =1.0 cm), and T1c (>1.0 cm and < or =2.0 cm) breast cancers. The charts of 204 patients who underwent axillary lymph node dissections for T1 breast carcinomas at our institution were reviewed. Of these, 23 (11%) patients had T1a cancers, 55 (27%) patients had T1b cancers, and 126 (62%) patients were diagnosed with T1c lesions. Fifty patients (24.5%) had axillary node metastases. Of those with T1a lesions, one (4.3%) patient had axillary node involvement, compared with 9 (16.4%) patients with T1b and 40 (31.7%) patients with T1c lesions. Nodal involvement was significantly increased in T1c cancer compared with either T1a (odds ratio = 8.24; P < 0.05) or T1b (odds ratio = 2.73; P < 0.05). Similar results were found in tumors with grade 3 nuclear pleomorphism (odds ratio = 10.45 versus grade 1 and 3.46 versus grade 2; P < 0.05). The presence of lymphovascular invasion was also associated with an increased likelihood of nodal involvement (odds ratio = 3.15; P < 0.05). Predictors of axillary lymph node metastasis in T1 breast carcinomas include increasing tumor size, grade 3 nuclear pleomorphism, and the presence of lymphovascular invasion. These predictors may have a role in stratifying patients with T1 breast carcinomas into subgroups that may benefit from less invasive methods of evaluating axillary lymph node status.

Axilla↗

PubMed1998

Thrombolysis-related intracranial hemorrhage: a radiographic analysis of 244 cases from the GUSTO-1 trial with clinical correlation. Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries.

BACKGROUND AND PURPOSE: Intracranial hemorrhage (ICH) is a serious complication of thrombolytic therapy. We systematically reviewed the radiographic features of 244 cases of symptomatic ICH complicating thrombolysis for acute myocardial infarction in the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-1) trial, correlated these observations with clinical data, and speculated on hemorrhage pathogenesis. METHODS: CT scans from 244 patients suffering symptomatic ICH were systematically reviewed for selected radiographic features, including ICH type, location, hematoma characteristics, mass effect features, hydrocephalus, and preexisting lesions. Hematoma volume was estimated by computer-assisted volumetric analysis. Data from this analysis were correlated with clinical data including hypertension, anticoagulation, age, thrombolytic regimen, and ICH timing. RESULTS: Most hemorrhages were large (median [25th, 75th percentile] volume, 72 mL [39, 118]), solitary (66%), lobar (77%), confluent (80%), and intraparenchymal (82%) with a blood/fluid level (82%) and little edema (median [25th, 75th percentile] volume, 9 mL [5, 16]). Hydrocephalus (P<.001), any one mass effect feature (P<.001), intraventricular hemorrhage (P=.022), mottled hematoma appearance (P=.050), and hematoma blood/fluid level (P<.001) were associated with higher hemorrhage volume in the radiographic analysis, as were older age (P=.005), treatment with combined streptokinase and tissue plasminogen activator (P=.034), and hemorrhage onset 8 to 13 hours after treatment (P=.008) in the clinical analysis. Subdural hemorrhage was a high-volume subgroup whose risk increased with antecedent trauma (P=.026) or syncope (P=.006). Deep intraparenchymal hemorrhage was associated with hypertension (P=.016), and multifocal ICH occurred significantly earlier after treatment (P=.002). CONCLUSIONS: Although the majority of postthrombolytic ICH are large, solitary, and supratentorial, the spectrum is diverse. Features of mass effect reflected the large volumes, and hematoma characteristics of mottling and blood/fluid levels were frequent. Thrombolysis-related coagulopathy and age appear to be the most important identifiable factors in the genesis of postthrombolytic ICH, but the hemorrhage subtype seen may reflect an interaction with other factors such as hypertension, ICH timing, antecedent head trauma, and syncope.

Cerebral Hemorrhage↗

PubMed1996

Target and trajectory guidance for interactive surgical navigation systems.

The proliferation of interactive surgical navigation systems (ISN) is evidence of their ability to provide useful information about current location and orientation at surgery. The utility of these systems would potentially expand with intuitive methods to guide the user towards a predefined target(s) along a predefined trajectory. A system of target and trajectory guidance is described comprised of three components: (1) auto-push that displays the plane perpendicular to the present trajectory that contains the preselected target and the distance from probe tip to this plane; (2) concentric circles and collinear spheres where spheres representing the target, entry point and wand tip are projected onto the 'autopush' plane as circles, thereby visually defining the rotations and translations required to reorient the wand to the predefined target and trajectory, and (3) projected trajectories where the ideal wand trajectory is projected onto two orthogonal planes, each of which contain the present wand trajectory. Together, these enhancements enable users of ISN to easily access small, deep intracranial structures along predefined surgical trajectories.

Humans↗

PubMed1995

Intracranial meningioma resection using frameless stereotaxy.

Thirty-four consecutive patients with intracranial meningiomas underwent 35 resections aided by an interactive surgical navigation system (ISN; "frameless stereotaxy"). System capabilities include real-time display of wand location, orientation, and relationship to nearby structures using multiplanar and three-dimensional presentation of magnetic resonance imaging (MRI) and/or computed tomography (CT) data obtained perioperatively. There were 16 patients with convexity tumors, five patients with sphenoid wing tumors, five patients with falx or parasagittal tumors, and eight patients with skull base tumors (two each: petroclival, cavernous sinus, olfactory groove, and planum sphenoidale). the ISN system was used to locate a minimal craniotomy (i.e., trephine) in 11 (32%) patients, to optimize bone flap design in 13 (38%) patients, to identify the location of parasagittal draining veins in five (15%) patients, and to locate the carotid or basilar arteries in 11 (32%) patients. The techniques provided limited benefit in cranial nerve preservation. No patient had permanent central neurologic morbidity. Where intended preoperatively, tumor resection was complete (i.e., > 98%) in all patients as determined via postoperative MRI. Interactive surgical navigation is a useful adjunct in the operative management of some patients with intracranial meningiomas.

Adult↗

PubMed1995

Adaptation of personal projection television to a head-mounted display for intra-operative viewing of neuroimaging.

We describe an adaptation of a personal projection television for intra-operative viewing of conventional neuroimaging and frameless stereotaxy displays. In addition to image display, the device provides surgical magnification and eye protection from body fluids. Image data is first processed by a scan converter to provide a National Standards Television Committee (NTSC) television signal. The adjustable optics of the system display are permanently secured to avoid displacement during surgery. A virtual image of the data is projected to an apparent size of four feet in the inferior visual field of the surgeon's dominant eye. Magnification is provided by the surgical telescopes mounted in the visor. Resolution of the device is consistent with that obtained in a slice of computed tomography or magnetic resonance imaging data. Optimal display of multiplanar data awaits improvement in density of the light emitting diode device used for image generation.

Humans↗

PubMed1993

Use of a frameless, armless stereotactic wand for brain tumor localization with two-dimensional and three-dimensional neuroimaging.

Preliminary experience with a frameless, armless stereotactic localization system in brain tumor surgery is presented. The localizing wand emits ultrasonic pulses that are detected by a table-mounted array of microphones--with triangulation of the emitter positions. The wand tip and trajectory are determined by proprietary computer software. Real-time display of this information is presented in multiple, two-dimensional or three-dimensional displays. Forty-eight patients underwent 52 craniotomies for brain tumors. The wand was used to assist in placing a minimal craniotomy in 48 cases, to determine the tumor/brain interface in 27 cases, to localize subcortical tumors in 14 cases, and to correlate the physiological mapping with the surface anatomy in 5 cases. In 12 instances, the wand was used in conjunction with frame stereotaxy and found to be comparable or superior. Triplanar (coronal, sagittal, transverse) two-dimensional images provided sufficient information for the detection of tumor boundaries but proved difficult to use to access a subcortical lesion; two-dimensional or three-dimensional images along the localization axis were more helpful. Frameless stereotaxy with this sonic wand system proved to be a useful adjunct to open-tumor biopsy or resection.

Adult↗

PubMed1993

Intraoperative localization using an armless, frameless stereotactic wand. Technical note.

A technique of "frameless" stereotaxy that allows real-time intraoperative neurosurgical localization is described. The system is composed of four components: a hand-held probe containing two ultrasonic emitters, a microphone array that is rigidly affixed to the operating table in proximity to the surgical field, hardware to control and detect timing of signal production and reception, and a color graphics computer workstation with software to calculate and present the location of the probe tip on reconstructed neuroimaging studies. Unlike previously reported mechanical or sonic navigational devices, this system is adaptable to a wide array of neurosurgical instruments, allows free movement of the operating table and conventional patient draping, and has accuracy in the hostile operating room environment that rivals that of frame stereotaxy. In the operating room environment, using four pulse pairs with the wand positioned optimally, reproducibility of a point in space is +/- 0.6 mm. The wand has a broad range of orientations that maintain error at or below 1.0 mm. The mean error when measuring distances within a 1000-cu cm cube is 1.1 +/- 1.0 mm (1.0% +/- 0.7%). The ability to localize a fourth point (a target) in space is typically within 1.5 mm (using computerized tomography scans with a 1-mm slice thickness) but is dependent on several variables. This technology provides a powerful yet flexible tool in the neurosurgical operating room.

Brain↗

PubMed1979

Spontaneous rupture of the liver. A complication of oral anticoagulant therapy.

Therapeutic doses of oral anticoagulants have been associated with spontaneous hemorrhage and rupture of apparently normal abdominal viscera. To our knowledge, this is the second reported case of such rupture involving the liver. The patient had sudden severe epigastric pain and signs of acute abdomen and shock. Discrete microscopic changes in the liver may precede massive hemorrhage.

Aged↗