Serious tumor seeding after brainstem biopsy and its treatment-a case report and review of the literature.

Stereotactic brain biopsies for histopathological diagnosis are a common technique in case of intracranial lesions, particularly in those not amenable for resection. Tumor seeding alongside the surgical trajectory after fine-needle aspiration is a known problem in several visceral tumors. Whereas in these cases a complete resection of the biopsy trajectory may later be performed, this strategy is not feasible in stereotactic brain biopsy. We report a case of tumor seeding along the entire biopsy tract after stereotactic biopsy of a brainstem metastasis. A 68-year-old male patient with a concomitantly diagnosed kidney lesion presented with a singular lesion in the brainstem. After confirmation of metastasis by stereotactic biopsy, stereotactic radiosurgery (SRS) was applied. The primary tumor was treated by laparoscopic nephrectomy. Three months after SRS, the patient presented with a secondary clinical deterioration for only a few weeks. The MRI scan showed tumor seeding along the entire biopsy tract. Salvage treatment including hypofractionated stereotactical irradiation and seven cycles of bevacizumab was administered to obtain symptom control. Massive seeding of tumor after stereotactic biopsy accordingly rare, taking into account that stereotactic biopsy is a very common neurosurgical intervention. Nonetheless, we think that the potential risk has to be kept in mind, as it might be neglected.

[Interdisciplinary position paper "Perioperative pain management"]. / Interdisziplinäres Positionspapier "Perioperatives Schmerzmanagement".

Despite many positive developments, postoperative pain and its treatment is still not always given the necessary attention. Severe pain after surgical procedures affects a significant proportion of patients. This very fact is not only detrimental to the immediate recovery process, but can also form the basis for the development of chronic pain conditions.An adequate and effective management of perioperative pain requires appropriate organizational structures. This multidisciplinary paper which was initiated by the Austrian Society for Anaesthesiology and Intensive Care and the Austrian Pain Society and developed together with numerous specialist and professional societies dealing with the subject aims at supporting the organization of perioperative pain management structures and to make best use of proven concepts. Additional recommendations describe specific interventions for selected types of intervention.

Evidence for a clonal origin of methicillin resistance in Staphylococcus aureus.

Soon after methicillin was introduced into clinical practice in the early 1960s, resistant strains of Staphylococcus aureus (MRSA) appeared, bearing a newly acquired resistance gene, mecA, that encodes a penicillin binding protein, PBP2a. MRSA have spread throughout the world, and an investigation of the clonality of 472 isolates by DNA hybridization was performed. All 472 isolates could be divided into six temporally ordered mecA hybridization patterns, and three of these were subdivided by the chromomosomal transposon Tn554. Each Tn554 pattern occurred in association with one and only one mecA pattern, suggesting that mecA divergence preceded the acquisition of Tn554 in all cases and therefore that mecA may have been acquired just once by S. aureus.

The molybdenum-pterin binding protein is encoded by a multigene family in Clostridium pasteurianum.

There are three variants of the molybdenum-pterin binding protein (Mop) encoded by three distinct genes in Clostridium pasteurianum. Nucleotide sequence analysis shows that the three mop genes have greater than 90% homology at the nucleotide level. Upstream from the coding region of each mop gene are potential promoter consensus sequences. Analysis of Mop purified from cells grown under nitrogen-fixing conditions indicates all three genes are expressed. Sequence analysis of the three mop genes and the gene products predicts that there are 10 amino acid replacements among the family. The amino acid replacements are chemically conservative accounting for the co-purification of the three variants of Mop. Protein chemistry data suggest the possibility that glutamic acid residues in Mop may be modified in vivo.

Multiple methicillin-resistant Staphylococcus aureus strains as a cause for a single outbreak of severe disease in hospitalized neonates.

Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of nosocomial infection. Outbreaks of infection caused by these pathogens are generally considered to be traceable to introduction of single strains into a hospital population. A large outbreak of bacteremic disease that recently occurred in our neonatal intensive care unit (11 episodes in 10 patients) involved 9 low birth weight infants and was associated with serious infection (4 episodes of meningitis). To determine the role of a single point source in this outbreak, isolates were characterized based on phenotypic and genotypic analyses. Phenotypic analysis included assessing hemolytic activity, phage typing, antimicrobial susceptibility testing and methicillin resistance population analysis. Genotypic analysis included assessment of plasmid profiles, dot-blot hybridization, restriction enzyme fragment pattern analysis and hybridization analysis of chromosomal DNA using a panel of staphylococcal gene probes. This analysis established that at least two distinct strains of MRSA were responsible for disease during this outbreak. This experience demonstrates the potential for MRSA to cause severe disease in the neonatal intensive care unit and indicates that the epidemiology of MRSA outbreaks is more complex than the spread of a single strain of bacteria.

Muscarinic cholinergic hyperactivity in schizophrenia. Relationship to positive and negative symptoms.

Based on the implication of increased muscarinic ACh activity in the production of negative symptoms, the association of decreasing cholinergic activity with positive symptoms, and the covariance of positive and negative symptoms in the psychotic phase of schizophrenia, a model of (DA) dopaminergic/(ACh) cholinergic interactions in schizophrenia was recently formulated. It suggests that DA/ACh balance is of central importance in schizophrenic pathophysiology and that muscarinic ACh activity increases in an attempt to maintain this balance in the face of increasing DA activity that occurs in the psychotic phase of the illness. The model further suggests that the muscarinic system exerts a damping influence on the emergence of positive symptoms associated with DA hyperactivity, but that this compensatory increase in muscarinic activity is accompanied by an intensification of negative symptoms. In the present study, we tested two important postulates of this model. We tested the prediction that muscarinic activity is increased in schizophrenia by comparing the effect of biperiden, an antimuscarinic M-1 agent, on REM latency in 12 drug-free schizophrenic inpatients and matched normal controls. We found that biperiden caused a smaller increase in REM latency in schizophrenic patients, suggesting that muscarinic activity is increased in schizophrenia. We tested the prediction that an anticholinergic agent would increase positive symptoms and decrease negative symptoms by studying the effect of 8 mg of biperiden/day for 2 days on positive and negative symptoms (assessed by the BPRS) in 30 medication-free schizophrenic inpatients.(ABSTRACT TRUNCATED AT 250 WORDS)

Outbreak in a New York City teaching hospital burn center caused by the Iberian epidemic clone of MRSA.

During an 18-month period in a burn center (January 1995 through June 1996), 109 single-patient MRSA isolates were identified and 102 isolates (94%) were available for DNA fingerprinting. Ninety-nine isolates (97%) carried the mecA polymorph I and Tn554 type E. Pulsed-field electrophoresis (PFGE) identified 8 patterns, of which 60 isolates were of pattern F2. The I:E:F clonal type and a stable drug multidrug resistant phenotype (sensitivity only to trimethoprim/sulfamethoxazole and vancomycin) indicated that these isolates were closely related to the Iberian clone of MRSA, which is widely spread in Europe. The initial source of I:E:F isolates was sputum 49%, blood 23%, wound 16%, urine 7%, and intravascular catheter tip 5%. Fifty-four percent of patients had smoke inhalation injury, and 51/53 required intubation or tracheostomy. Forty-three isolates were considered invasive (positive blood culture). The overall mortality was 30%. Despite infection control measures, the I:E:F clone continued to be recovered from patients during the 18 months of study. This outbreak is the first known report of the Iberian MRSA clone in the United States.

Tracing the spread of methicillin-resistant Staphylococcus aureus by Southern blot hybridization using gene-specific probes of mec and Tn554.

In a community hospital in Brooklyn, New York, over a 3-year period, 79 methicillin-resistant Staphylococcus aureus (MRSA) isolates from five different case clusters were subtyped by Southern blot hybridization with two previously characterized gene probes, mec and Tn554. Together, the genotyping enabled the hospital infection control team to differentiate simultaneous MRSA clusters in the surgical intensive care unit (type I:A) and the open heart unit (type II:J), document the spread of one strain (type I:A) between roommates, identify an endemic strain (type II:J) from cardiac monitors and medical personnel, and identify an unrelated outbreak strain (type II:NH) in the labor and delivery unit. On the basis of this investigation it is clear that the routine DNA fingerprinting of MRSA in health care facilities, to monitor their spread and identify cases of nosocomial infections, is an important infection control measure.

A city-wide outbreak of a multiple-drug-resistant strain of Mycobacterium tuberculosis in New York.

SETTING: Incident patients with active tuberculosis (TB) resistant to two or more drugs in New York City hospitals in 1992. OBJECTIVE: To examine the New York-wide distribution of Public Health Research Institute (PHRI) strain W of Mycobacterium tuberculosis, an extremely drug-resistant strain identified by a 17-band Southern hybridization pattern using IS6110, during the peak tuberculosis year of 1992. We also compared strain W with other strains frequently observed in New York. DESIGN: Blinded retrospective study of stored M. tuberculosis cultures by restriction fragment length polymorphism (RFLP) DNA fingerprinting, and chart review. RESULTS: We found 112 cultures with the strain W fingerprint and 8 variants in 21 hospitals among incident patients hospitalized in 1992. Almost all isolates were resistant to four first-line drugs and kanamycin. This single strain made up at least 22% of New York City multiple-drug-resistant (MDR) TB in 1992, far more than any other strain. Almost all W-strain cases were acquired immune deficiency syndrome (AIDS) patients. The cluster is the most drug-resistant cluster identified in New York and the largest IS6110 fingerprint cluster identified anywhere to date. CONCLUSION: Because recommended four-drug therapy will not sterilise this very resistant strain, there was a city-wide nosocomial outbreak of W-strain TB in the early 1990s among New York AIDS patients. Other frequently seen strains were either also very resistant, or, surprisingly, pansusceptible. Individual MDR strains can be spread widely in situations where AIDS and TB are both common.

Intraoperative motor and sensory monitoring of the cauda equina.

A set of standard techniques to monitor the motor and sensory function of the cauda equina is proposed for surgery in the lumbosacral spinal canal for the release of a tethered cord or the removal of a neoplasm. Continuous loudspeaker-controlled recording of electromyographic activity in four leg muscles of both sides supplied the surgeon with immediate feedback on injury to any of the motor roots from the second lumbar to the fourth sacral segment. Continuous recording of tibial nerve somatosensory evoked potentials yielded information about the functional state of parts of the lumbosacral sensory pathways. Motor roots could be identified by electrical stimulation in the operating field with bipolar stimulation forceps and recording of compound muscle action potentials from the leg muscles. Sensory nerve roots could be identified by nerve root somatosensory evoked potentials recorded from the scalp after the electrical stimulation of the exposed nerve. This set-up is a combination of previously developed monitoring techniques and provides the surgeon with functional information: 1) continuous feedback on the state of the endangered motor and sensory function of the cauda equina; and 2) rapid anatomical identification of nerve roots and their distinction from fibrous or neoplastic structures.

Preoperative activation and intraoperative stimulation of language-related areas in patients with glioma.

OBJECTIVE: Evaluation of the accuracy of preoperative localization of language-related cortex by magnetic resonance imaging-guided positron emission tomography. METHODS: Patients with gliomas in the left dominant hemisphere were examined preoperatively with magnetic resonance imaging-guided positron emission tomography and intraoperatively by electrical stimulation of cortex. RESULTS: A verb generation task yielded more intense and better lateralized local increases of cerebral blood flow in the positron emission tomographic examination than did a naming task. Significant correspondence of preoperative and intraoperative findings was observed for the verb generation task. Cortical sites with aphasic disturbance during electrical stimulation had a significantly higher cerebral blood flow increase during preoperative activation than did sites without intraoperative language impairment. Areas with cerebral blood flow increases above an optimum threshold had 73% sensitivity and 81% specificity to predict aphasic disturbance during intraoperative stimulation. CONCLUSION: The data suggest that with further technical improvements, imaging of language function may become a preoperative diagnostic tool for patients with tumors close to language-related brain structures.

The mapping and continuous monitoring of the intrinsic motor nuclei during brain stem surgery.

A comprehensive technique was developed for continuous electrophysiological monitoring of intrinsic brain stem motor function during surgery to remove space-occupying lesions in the fourth ventricle and brain stem. The technique is analogous to that used during surgery in the cerebellopontine angle; motor nuclei and peripheral pontine fiber tracts of Cranial Nerves III-XII are identified by the electrical stimulation of structures in the operative field and the evaluation of the compound muscle action potentials recorded from the corresponding muscles of the head. Nerve function is monitored continuously by recording the ongoing electromyographic activity in these same muscles. Broadcasting electromyographic responses through a loudspeaker gives the surgeon immediate feedback on the status of the motor nuclei being monitored. Advantages of this technique include 1) the positive, objective identification of the nuclei and fiber tracts; 2) the continuous feedback on the status of these structures; 3) a safe approach through the fourth ventricle to the lesions in the brain stem; 4) the positive identification of the boundaries between the neoplasm and the motor structures of the rhomboid fossa; and 5) a warning to the surgeon of potentially harmful nerve manipulations (contact, dissection, transection) during surgery. After this technique was used in 16 consecutive operations to remove cavernomas (n = 9), gliomas (n = 4), and other types of tumors (n = 3), surgical and neurological results showed the method to be reliable and simple to perform.

Computer-assisted neurosurgery by using a noninvasive vacuum-affixed dental cast that acts as a reference base: another step toward a unified approach in the treatment of brain tumors.

OBJECT: The purpose of the study was to evaluate the use of the Vogele-Bale-Hohner (VBH) mouthpiece, which is attached to the patient's upper jaw by negative pressure, for patient-image registration and for tracking the patient's head during image-guided neurosurgery. METHODS: A dynamic reference frame (DRF) is reproducibly mounted on the mouthpiece. Reference points, optimally distributed and attached to the mouthpiece, are used for registration in the patient's absence on the day before surgery. In the operating room, the mouthpiece and DRF are precisely repositioned using a vacuum, and the patient's anatomical structures are automatically registered to corresponding ones on the image. Experimental studies and clinical experiences in 10 patients confirmed repeated (rigid body) localization accuracy in the range of 0 to 2 mm, throughout the entire surgery despite movements by the patient. CONCLUSIONS: Because of its noninvasive, rigid, reliable, and reproducible connection to the patient's head, the VBH vacuum-affixed mouthpiece grants the registration device an accuracy comparable to invasive fiducial markers.

Electromyographic timing analysis of forward and backward cycling.

PURPOSE: Backward walking to running progressions are becoming a popular, nontraditional component of functional knee rehabilitation programs. The purpose of this electromyographic (EMG) and motion analysis study was to compare the activation duration of the vastus medialis, vastus lateralis, rectus femoris, medial hamstrings, lateral hamstring, tibialis anterior, and gastrocnemius muscles during forward and backward cycling. We hypothesized that the hamstrings would demonstrate greater activation duration during backward cycling. METHODS: The right lower extremity of 12 healthy subjects (6 male and 6 female) was instrumented with surface EMG electrodes and retroreflective markers to confirm lower extremity kinematic consistency between conditions. RESULTS: Statistical analysis of hip, knee, and ankle kinematics (200 Hz sampling rate) and gender failed to reveal significant differences between conditions (P > 0.05). Quadrant analysis of muscle activation duration with Bonferroni corrections for multiple comparisons revealed that medial and lateral hamstring activation duration was greater during the early recovery phase (quadrant III) of backward cycling than forward cycling (P < 0.00156). Rectus femoris activation duration was greater in the early propulsive phase of backward cycling (quadrant 1) (P < 0.00156) and in the early recovery phase of forward cycling (quadrant III) (P < 0.00156). CONCLUSIONS: These findings lend support for the use of backward cycling during the early recovery phase (quadrant III) to achieve a selective hamstring muscle response of relatively decreased patellofemoral stress and anterior cruciate ligament strain.

Effect of anticholinergic medication on positive and negative symptoms in medication-free schizophrenic patients.

It is generally assumed that anticholinergic drugs have no effects on schizophrenic symptomatology. A few studies, however, indicate that anticholinergic agents aggravate psychotic symptoms and antagonize therapeutic effects of neuroleptics in schizophrenic patients; more recently, some investigators have observed that these agents appear to benefit negative symptoms. In an effort to resolve this issue, we studied the effects of 2 days of treatment with biperiden on positive and negative symptoms in 15 medication-free schizophrenic patients. Positive symptoms increased significantly, while there was a trend toward a decrease in negative symptoms. The implications of these findings for the role of the cholinergic system in schizophrenia are discussed.

Performance in picture naming and word comprehension: evidence for common neuronal substrates from intraoperative language mapping.

Correlations of naming ability and performance in the Token Test are known from aphasia; however, the mechanisms underlying these correlations are unclear. Naming tasks are commonly used in intraoperative mapping for identification of cortical areas involved in language processing. In the present study, we measured performance in an elementary Token Test task, i.e., single word comprehension, during electrical stimulation of cortical sites at which this stimulation previously had disturbed the naming process. It was found that at about half of the sites at which naming could be disturbed electrical stimulation also led to disturbances in Token Test performance, indicating that there are common neural structures critical for performance in both tasks. These findings are discussed in terms of a multilayered semantic network in which the level of the simultaneous binding of features into concepts and the level of units that are organized with respect to semantic relations may be disturbed separately.

Accuracy and clinical use of a novel aiming device for frameless stereotactic brain biopsy.

Aiming devices enable the use of neuronavigation systems for rigid instrument guidance mimicking the possibilities of a frame-based system without having a stereotactic frame affixed to the skull. The aim of the presented work was to investigate the phantom targeting accuracy of the Vertek aiming device (Medtronic Inc., Louisville, USA) and whether it can be safely and accurately applied in a concept of minimally invasive brain biopsy in which multi-modal image fusion, image-to-patient registration and head immobilization were based on a non-invasive vacuum mouthpiece. A plastic model of a head with 20 target beads broadly distributed around the head volume was used for determination of CT-based targeting accuracy. Every target was punctured 5 times totaling 100 needle positionings. Accuracy was evaluated on postoperative CT scans with the needles in place. The mean normal deviation (n = 100) was 1.5 +/- 0.8 mm and the mean angle of deviation was 1.1 +/- 0.7 degrees. In a preliminary clinical series in ten patients diagnostic biopsy sampling of intracranial lesions with a median diameter of 28 mm (range: 12-90 mm) could be achieved in all patients and no biopsy related complications were recorded. The experimental results showed a similar accuracy to frame-based stereotaxy. The device facilitates trajectory alignment via two pivot joints and the actual depth and location of the biopsy needle can be monitored. Within the limitations of a preliminary study, brain biopsy may be accurately and safely performed for lesions > or = 12 mm.

[Functional magnetic resonance imaging before motor cortex stimulation for phantom limb pain]. / fMRT vor Motorkortexstimulation beim Phantomschmerz.

This study deals with the diagnostic value of functional magnetic resonance imaging (fMRI) in a patient with phantom limb pain following traumatic amputation of the right arm. After failure with medication, resection of stump neurinoma, and spinal cord stimulation, fMRI with evidence of cortical reorganization was performed. Tactile stimulation of the perioral region and motor imagery with cranial, tactile stimulation of the stump led to a caudal shift in fMRI activity. Subsequent motor cortex stimulation brought relief from the pain. By detecting cortical reorganization, fMRI contributes to the indication for motor cortex stimulation for phantom pain and aids in electrode positioning.

Accidental intracerebroventricular injection of anaesthetic drugs during induction of general anaesthesia.

A 51-year-old patient scheduled for surgery under general anaesthesia was accidentally given remifentanil 150 microg and propofol 1% 10 ml through an intracerebroventricular totally implantable access port placed in the right infraclavicular region, which was mistakenly thought to be an intravenous line. Severe pain in the head and neck caused the mistake to be discovered rapidly, and 20 ml of a mixture of cerebrospinal fluid and the anaesthetic drugs were aspirated from the implantable access port. The patient suffered no apparent adverse neurological sequelae.