Operative Versorgung von HWS-Verletzungen

The three most frequent sources of complications in the treatment of cervical-spine injuries are the indications adopted, the access route used, and the implant selected and its application . The management of complex injuries can be significantly facilitated if it is implemented with due consideration for the basic premises of spinal surgery: the operator must be familiar with the biology and mechanics of the vertebral column and with the potentials and limitations of the implants available for selection and must have analysed the actual instability in each case. There are also critical segments that have different biomechanical characteristics from the other sections of the spine. Some pathologic conditions also involve problems peculiar to themselves in addition to such anatomical characteristics, and these thus affect the choice of surgical procedure. In such situations (fractures associated with ankylosing spondylitis, unstable fractures at the cervicothoracic junction, insufficient anterior support with dorsal instrumentation, stabilization with incomplete reduction, multisegmental instability) excessive strain on the implant must be expected, which entails the risk of early implant failure, especially if the associated biomechanical condition is misinterpreted.     

Volumetrical measurements in vestibular schwannoma, the influence of slice thickness and patient's repositioning.

OBJECTIVE: Conservative treatment in vestibular schwannomas is mainly dependent on optimal tumor size determination. The first objective of this study was to establish interobserver and intraobserver variability and the accuracy and reproducibility of three different measurement methods: one bidimensional and two volumetrical. The second objective was to evaluate the influence of the use of different magnetic resonance imaging (MRI) slice thickness and the influence of patient's repositioning on the measurements' outcome. STUDY DESIGN: Two consecutive studies have been prospectively performed, both mainly concerning volumetrical measurements. SETTING: Both studies were performed in a tertiary academic, multidisciplinary center. PATIENTS: In the first study, 19 patients were included between March 1996 and May 2002, with a total of 52 scans. The second study comprised 14 patients. All patients in the first study had at least two MRI examinations performed according to a standard protocol (T1-weighted gadolinium-enhanced, slice thickness of 3 mm, and interslice gap of 0.3 mm). The population in the second study underwent a conservative wait and scan (W&S) treatment. METHODS: Both studies are discussed separately. In the first study, all scans were measured by four investigators, two of whom performed the measurements twice using three different methods. The first method concerns a manually performed bidimensional surface measurement along the petrous pyramid. The second method concerns a semiautomatic volumetrical measurement on a computer, relying on contour detection, and the last method concerns a fully automatic volume reconstruction also performed on a computer using different gray shade scales.All 14 patients included in the second study underwent three magnetic examinations. Three different T1-weighted gadolinium-enhanced sequences were used: the first using a slice thickness of 1 mm, the second again with 1-mm slice thickness but after having repositioned the patient. In the third sequence, a slice thickness of 3 mm was used. All scans were measured by two investigators using the three different methods, as described previously. RESULTS: The manual surface method shows large intraobserver variability, and its reproducibility is significantly lower compared with volume measurements. Because of a relatively large systematic error in small tumors, sensitivity of growth detection is low. Both volumetrical methods are hardly interobserver- and intraobserver-dependent, and the gray shade method turned out to be the most accurate. Radiologic progression is only significant at a volume increase of at least 50%. The influence of patient repositioning is negligible, whereas the use of 1-mm slice thickness seems to be superior to a 3-mm slice thickness. CONCLUSION: The volumetrical gray shade method is the most accurate method to detect early tumor progression. As tumor increase of at least 50% is needed to be able to speak of statistically significant tumor growth, the absence of radiologic progression does not mean that there is no tumor growth. Repositioning of the patient has no influence on the measurements' outcome, whereas for optimal magnetic resonance imaging examinations, a 1-mm slice thickness protocol seems to be superior.     

Increasing the efficiency of paraffin tissue microarrays by packing the paraffin tissue core biopsies in a honeycomb pattern.

Paraffin tissue microarrays (PTMAs) are blocks of paraffin holding up to 1000 paraffin tissue core biopsies (PTCBs) for high throughput molecular analysis. The number of PTCBs in a PTMA depends on the surface area of the PTMA, the diameter of and the distance between the PTCBs and on their arrangement inside the assembled PTMA. The PTCBs are usually arranged in a rectangular x-y pattern of rows and columns. This design facilitates the construction of a PTMA because the operator simply turns the wheels of an x-y-table for a set, unchanging distance. The evaluation of the stained sections is also relatively easy. However, this rectangular arrangement means wasted space in the PTMA. To reclaim this space, the PTCBs could be arranged in a honeycomblike pattern. For every 8 rows in the conventional rectangular arrangement, 1 additional row of PTCBs can be packed. However, the researcher has to become accustomed to this uncommon arrangement when filling and evaluating the PTMA. Automatic slide readers and specially designed computer programs for the digital evaluation of the PTMAs can be helpful. In summary, the arrangement of PTCBs in a honeycomblike pattern increases the density and number of specimens stored in a PTMA, thereby enhancing its efficiency.     

Screen sensitivity in photosensitive children and adolescents: patient-dependant and stimulus-dependant factors.

Television viewing is the most frequent cause of photogenic attacks in daily life. In the present study, we examined 48 photosensitive children and adolescents to find out: 1) whether hypersynchronous activity is induced less often by viewing a PC monitor than a television screen and 2) whether certain images are more likely to cause hypersynchronous activity than others. All subjects were tested for sensitivity to intermittent photic stimulation (IPS) and to a black and white striped pattern on cards. Additionally, all were subjected to stimuli from four different images (vertical black and white striped pattern, geometric figures, text, and a painting by Max Pechstein - 1913, Italian church), presented on a television screen (with an image regeneration frequency of 50 Hz) and on PC screens (with regeneration frequencies of 48 and 100 Hz). A total of 21 non-photosensitive, healthy children and adolescents served as controls. Of the 48 photosensitive subjects 13% were also pattern sensitive (cards), and 33% exhibited screen sensitivity. No differences were found between the three monitor types. However, the hypersynchronous reactivity to the four images presented was significantly different, with high contrast vertical striped pattern being the most provocative. Non-photosensitive subjects did not react to any of the stimuli. The results of the present study show that screen-dependant factors are less important than image-dependant factors.     

Oral administration of taurolidine ameliorates chronic DSS colitis in mice.

Taurolidine (TRD) has antimicrobial and anti-inflammatory properties. However, the anti-inflammatory effects of TRD in inflammatory bowel diseases (IBD) have not been investigated. Here, we have analyzed the toxicity of TRD after oral long-term application in mice and examined the impact of oral TRD in a dextran sulfate sodium (DSS) model of experimental colitis. Female C57/BL6 mice received TRD in various concentrations (0.1% to 0.4%) for 60 days. Toxicity was evaluated by use of a disease activity index (DAI) and histological examination of major metabolic organs. Furthermore, the impact of 0.2% TRD on a chronic DSS colitis was examined by daily DAI, histological crypt damage score (CDS), bacterial translocation into mesenteric lymph nodes (MLN), and colonic expression of tumor necrosis factor (TNF) alpha, transforming growth factor (TGF) beta, interleukin (IL)-1beta, IL-6, cytochrome oxidase (COX)-2, and monocyte chemotactic protein (MCP)-1 by real-time polymerase chain reaction (PCR). Oral TRD administration for 60 days was well tolerated by the animals and did not show any toxic effects in terms of DAI and histological changes. TRD treatment of DSS colitis led to increased survival of 100%, compared to 33% in the untreated colitis group (p < or = .005). Clinical amelioration was mirrored by significantly reduced DAI and CDS in the TRD treated colitis. Colonic cytokine expression and bacterial translocation into MLN showed no differences between both groups. We thus report for the first time that oral application of TRD results in amelioration of an experimental IBD model. We hypothesize direct intraluminal antimicrobial effects of TRD as well as anti-inflammatory effects during the acute phase of DSS colitis.     

Tissue engineering: a challenge of today's medicine

During the last years, tissue engineering-based therapies have been introduced in clinical practice in the head and face area. The regeneration of complex tissue structures for all sites of the body is envisioned for the future. In the present situation, specialists of the different fields publish excellent research papers in specialised journals. As a result, the scientific community, seperated towards distinct sub-specialities, has difficulties in communication. To overcome this problem, the demanding, complex and interdisciplinary aspects of tissue engineering has to be approached from new ways. We have conceptualised Head & Face Medicine therefore as a thematically broad ranged journal, including all disciplines involved in the head and neck area. We hope this journal will attract basic researchers and clinicians who are involved in investigating and applying complex themes (examplified by tissue engineering) in the head and face region and will contribute to a gain in scientific information, communication, and collaboration in order to improve the outcome of patient treatments.