[A solution to add digital signatures to medical images according to the DICOM standard: embedded systems]. / Ein Lösungsweg, um medizinische Bilder mit digitalen Signaturen nach dem DICOM-Standard zu versehen: Embedded Systems.

Radiology departments often underestimate the importance of protecting medical data during transmission, including the precautions taken to ensure data protection. In teleradiology, transmitted as well as stored patient data have to be signed digitally according to the currently valid regulation (Rontgenverordnung, RoV). The DICOM standard facilitates a digital signature. So far, medical image manufacturers only announced to support this security feature. We introduce a solution that extends the feature of digital signing to older modalities.

Patient data security in the DICOM standard.

The DICOM committee added the section "Security Profiles" to the DICOM standard, in order to provide the opportunity of safe communication between health care system partners. Data complying with the DICOM standard--e.g. pictures, signals or reports of examinations can be provided with one or more digital signatures. Attention should be paid to the fact that these possibilities of the DICOM standard are available or can be supplied subsequently by new acquisitions of radiological modalities. The required information to check these prerequisites are given.

[Does the digital signature of the DICOM standard meet the requirements of German law?]. / Entspricht die digitale Signatur des DICOM-Standards dem deutschen Signaturgesetz?

The DICOM standard offers the possibilities to generate electronic signatures, valid according to German laws. This enhances the reliability of the correlation between image and patient data. However, only so called qualified electronic signatures--conveniently issued by an accredited supplier--are permissible and not rejectable as evidence in German jurisdiction and are completely equivalent to the handwritten signatures. These qualified electronic signatures can be executed only by individuals, whereas the former are not applicable to technical apparatus like image generating modalities. In consequence, a modality is able to provide its pictures with a "common or advanced signature" solely. This limits the use of the digital signature of the DICOM standard for further applications, e.g. the verifiability within the teleradiology.

[Thiel method fixed cadaver ears. A new procedure for graduate and continuing education in middle ear surgery]. / Nach Thiel fixierte Leichenohren. Ein neues Verfahren für die Aus- und Weiterbildung in der Mittelohrchirurgie.

BACKGROUND AND OBJECTIVE: An efficient training program in ear surgery needs suitable models to learn the specific preparation techniques. However, conventionally fixed or fresh frozen ears of human corpses do not meet all demands. Therefore we investigated the feasibility of ears fixed according to Thiel for surgical training in the temporal bone lab. METHODS: Various surgical techniques on external and middle ears were evaluated on ears from cadavers fixed according to Thiel. Structure and consistency of the tissues were compared to vital conditions by means of a standardized questionnaire. RESULTS: Structure and consistency of the tissues of the auditory canal, the tympanic cavity and the mastoid were comparable to vital conditions. Merely the cartilage of the auricle was considerable softened. This enabled a surgical preparation under conditions close to the intravital situation. CONCLUSIONS: Under the aspects of quality assurance and efficiency of continuous medical education in middle ear surgery, the Thiel fixation technique provides an excellent prerequisite.

Which joint position puts the axillary nerve at lowest risk when performing arthroscopic capsular release in patients with adhesive capsulitis of the shoulder?

The success of arthroscopic capsular release of the glenohumeral joint depends on complete incision of the inferior capsule. This study determined the distance between capsule and the axillary nerve in different joint positions. In 14 human shoulder specimens the anterior joint capsule and axillary nerve were dissected, and the anterior joint capsule was incised between the 1 and 5 o'clock positions. The shortest distance between the insertion of the inferior capsule and the axillary nerve was measured at the glenoid and humeral insertions in abduction, adduction, internal, and external rotation. The axillary nerve is surrounded from soft connective tissue and is closer to the humeral than to the glenoidal attachment of the joint capsule. During abduction and external rotation the nerve stays in its position while the glenohumeral capsule tightens, which increases the distance between the two structures. This results in the following distances: to the glenoidal/humeral capsule insertion: in adduction and neutral rotation, 21.2+/-4.2/14.2+/-2.6 mm; in abduction and neutral rotation, 24.0+/-4.9/15.0+/-5.0 mm; in abduction and internal rotation, 21.1+/-6.6/14.6+/-3.7 mm; and in abduction and external rotation, 24.9+/-3.8/16.4+/-4.4 mm. Thus, when performing arthroscopic capsular release the incision of the glenohumeral joint capsule should be undertaken at the glenoidal insertion in the abducted and externally rotated shoulder.

Entrapment of the lingual nerve due to an ossified pterygospinous ligament.

During a routine dissection course at the University of Muenster (Germany) an unusual course of the lingual nerve was found with entrapment of the nerve between a widely ossified pterygospinous ligament and the medial pterygoid muscle. Furthermore, the nerve's mobility was restricted by a more distal anastomosis with the inferior alveolar nerve. Although incomplete or complete ossification of the pterygospinous ligament is not uncommon, the combination with a medial course of the lingual nerve has not been described before. Besides practical importance for surgeons and anesthetists, the entrapment of the lingual nerve may lead to lingual numbness and pain associated with speech impairment.

The posterior subdeltoid approach: a modified access to the posterior glenohumeral joint.

A modified surgical approach to the posterior aspect of the glenohumeral joint and/or the dorsal glenoid is described. This access does not alter any muscle insertion or neuromuscular planes. After the skin incision is made, the inferior border of the spinal part of the deltoid is identified and the deltoid muscle is mobilized and retracted, thus offering an excellent approach to the interval between the infraspinatus and teres minor muscles. This interval is split parallel to the muscle fibers. This surgical approach was first established in 10 cadaverous shoulders and then performed in 12 patients with posterior shoulder pathology. In the cadaver study, the closest distance to the axillary nerve with this approach was 22 mm. In all 12 cases, the surgical procedure could be performed without any problems.

[Surgical procedures in mouth, jaw and facial surgery in Thiel embalmed body donors]. / Operative Verfahren der Mund-, Kiefer- und Gesichtschirurgie an nach Thiel fixierten Körperspenden.

METHODS: This study investigates whether human cadavers embalmed according to Thiel can be used for research and education in oral-maxillo-facial surgery. Different surgical approaches were tested on such cadavers. The usability of the specimen was judged jointly by anatomists and surgeons. Color, structure, and consistency of the different tissues were comparable to vital conditions. Thiel's embalming technique applied to human cadavers provides an optimal basis for research and for basic and postgraduate medical education.

[Pathomorphology of laser-induced interstitial tumor thermotherapy of the liver]. / Pathomorphologie der Laser-induzierten interstitiellen Tumor-Thermotherapie an der Leber.

The aim of this study was to analyse pathomorphological findings after treatment with laser induced tumor thermotherapy (LITT) on liver tissue and to correlate the results with magnetic resonance imaging. LITT was performed ex vivo and in vivo using a Neodym-YAG-Laser. Lesions were monitored by MR-thermometry ex vivo and by contrast-enhanced MRI in vivo. After LITT the lesions were examined macroscopically, histologically, and electronmicroscopically. LITT-induced tissue damage was qualitatively evaluated, classified, and quantified by means of digital image analysis. Four different zones of tissue damage were identified within the lesions. Adjacent to the applicator the tissue was completely ablated while more peripheral lesions exhibited only sublethal cell damages seen by EM. In vivo the pattern of tissue injury followed the lobular architecture of the liver tissue. Ultrastructural examination revealed only in areas of minor tissue injury intact sinusoidal patterns. MRI overestimated the diameter of the core zone of complete tissue ablation both ex vivo and to a lesser extent in vivo.

[Precision and comparison of CT-, MRI- and DL-controlled interventions exemplified by lumbar facet infiltration--an experimental study]. / Präzision und Vergleich von CT-, MR- und DL-gesteuerten Interventionen am Beispiel der lumbalen Facetteninfiltration--eine experimentelle Untersuchung.

We evaluated the accuracy of the needle tip representation by different imaging techniques for the guidance of facet infiltrations. For visualisation of the lumbar facet joints we used a high-field magnetic resonance tomograph (MRT) with a 2.0 Tesla field and 3.5 mm slice thickness, an open low-field magnetic resonance tomography (MRT) with an 0.064 Tesla field and 9 mm slice thickness, and IMATRON electron beam computed tomograph (EBCT) with a slice thickness of 6 mm, and a mobile C-arm fluoroscope. The study was performed on 4 human cadaveric lumber spine preparations, each of which had 8 facet joints. Under imaging control, special injection needles were placed as close as possible to the facet joint space. Following placement of he needle, all specimens were scanned with the electron beam tomograph using a slice thickness of 1.5 mm. The thin-slice study served as the gold standard. The distance between the tip of the needle and the facet joint was measured in all the images. Comparison of the different modalities with the gold standard revealed the following results: 1) median values of the absolute differences were 1.25 mm for high-field MRI, 1.35 mm for 6 mm EBCT, 2.05 mm for low-field MRI, and 2.30 mm for X-ray fluoroscopy. 2) While there was no statistically significant difference in the accuracy of tip localization between high-field MRI and 6" EBCT (p = 0.293), both systems were more precise than low-field MRI (p = 0.04) and X-ray fluoroscopy (p = 0.009). When choosing the best imaging technique, such additional factors as radiation, costs and time, must also be considered. Provided necessary radiological precautions are taken, and assuming careful pre-interventional planning, CT. EBCT and X-ray fluoroscopy are currently more effective than the expensive, time-consuming and costly magnetic resonance tomography.

[Virtual simulation for optimizing the range of motion in hip alloarthroplasty using an adapted thrust-plate prosthesis model]. / Virtuelle Simulation zur Optimierung des Bewegungsspiels einer Hüftalloarthroplastik am Beispiel der adaptierten Druckscheibenprothese.

The purpose of the present study was to increase the free range of motion in conventional trust-plate prosthesis design and to optimize the trust-plate contact as well as the osteointegration area below the trust-plate. For the first part of the study, the two-dimensional geometry of the osteotomy plane was demonstrated in 25 CT-reconstructed femora after performing a virtual cut at a CCD angle of 135 degrees. In the second part, we constructed a prototype of an anatomic adapted trust-plate prosthesis (A-TPP) with an optimized trust-plate and corpus geometry based on the three-dimensional data of three human cadaveric femurs (age 67-75 years). In the final step, we documented the range of motion with computer-aided movement-mapping and compared the conventional TPP with the A-TPP. The results showed a wide variance in osteotomy geometry in the 12 femurs. With the A-TPP, we were able to obtain a much better fit in the trust plate surface. The movement-mapping showed a much higher range of motion in the A-TPP implant. With the A-TPP, the implant surface area for osteointegration could also be significantly increased.

Reflection contrast microscopy (RCM): a forgotten technique?

Reflection contrast microscopy (RCM), which utilizes the optical phenomena caused by oblique epi-illumination in combination with a specific optical apparatus, provides an approach for exploring biological phenomena in greater detail. The lack of stray reflection makes it superior to other microscopes. It bridges light and electron microscopic capabilities by allowing the analysis of ultrathin sections beyond the usual light microscopic magnification. By using consecutive image analysis, quantitation can be achieved. The wide range of applications of RCM can be combined with most microscopical techniques, so extending the spectrum of information that can be gathered. Twenty-five years after the development of RCM, there is still scope for its application in modern cell biology.

Live interdisciplinary teaching via the internet.

The independence of teachers and students is one of the main advantages of teleteaching. Specialties considered unsuitable for combined lessons are manageable using the internet. This study outlines simultaneous communication with students and lecturers over long distances between the anatomical dissection laboratory, the operating theatre, and the lecture hall. In several three-directional on-line lectures, different equipment was used. Students could also participate using personal computers from other locations. During the presentations, the participants have the opportunity to discuss problems with any lecturer. It was possible to demonstrate sufficient transmission capability for real-time application with the use of the new internet technology. No important qualitative differences can be reported between: hardware and software based solutions; or commercial and free offers. Although it is often difficult to reconcile the timetable of surgeries and lectures, multimedia on-line teaching via the internet provides new potential for interdisciplinary medical education.

[New paths for Internet generated learning in anatomy]. / Neue Wege der Internet-gestützten Lehre in der Anatomie.

For the purposes of a functioning information and knowledge based medicine the conditions for the medical education are crucial. Although multimedia based courses and tutorials via the Internet seem to serve best for a more effective teaching and new didactics, respective anatomical offers in Germany are scarce and thus practice and experience are limited. Only simple digital equivalents of conventional contents and methods can be found, whereas the potencies of the new media are not realized in didactic concepts. Substantial advantages of web based tutorial systems are an intensive use of the feedback possibilities, the opportunity for continuous updating of the contents, the favourable distribution, and faster utilization of improved techniques. This paper introduces the adaptation of different techniques and the development of concepts and notions of modern Internet based teaching by the way of three different events in anatomical education for medical students and doctors. HistoNet 2000 was developed as an interface of lectures, seminars and practical courses in microscopy. The online transmission of a microscopical course as an interactive practical teleteaching was performed by the way of asymmetric data transfer via the ADSL-technology. Multicasting was used as well and has also been applied for the third project. In this multimedial online teaching different specialties were joined together for interdisciplinary courses via the Internet. These new technologies lead to enhanced efficiency in teaching and enlarge the educational offer. Specific Internet adapted teaching and learning projects have to be developed.

Traumatic complications of acupuncture. Therapists need to know human anatomy.

OBJECTIVES: To review the traumatic injuries that have been associated with acupuncture and to discuss how these adverse effects may be reduced by increased awareness of normal anatomy and anatomical variations. METHODS: Literature search accompanied by postmortem anatomical studies. RESULTS: Traumatic lesions after acupuncture have been described in thoracic and abdominal viscera, in the peripheral and central nervous systems, and in blood vessels. Deaths have been recorded from pneumothorax and cardiac tamponade. The anatomical structure of the body at several acupuncture points is such that needles can reach vulnerable structures. CONCLUSION: While the frequency of adverse effects of acupuncture is unknown and they may be rare, knowledge of normal anatomy and anatomical variations is essential for safe practice and should be reviewed by regulatory bodies and those responsible for training courses.

[Possibilities of spinal endoscopy within the scope of minimal invasive intervention--an experimental study]. / Möglichkeiten der Spinaloskopie im Rahmen der minimal invasiven Intervention--eine experimentelle Untersuchung.

The purpose of the present study was to evaluate, in vitro, a newly designed spinaloscope with a diameter of 1.8 mm, with integrated portals for instruments and irrigation. The 0 degree optical system has a resolution of 6,000 pixels. The instrument portals can be used for surgical lasers, biopsy forceps or burrs. We carried out our evaluations on fresh (unfixed) human lumbar spine specimens. The position of the endoscope was documented by CT scans. The endoscope was introduced into the spinal canal via the hiatus sacralis using a blunt trocar. The various structures and tissues were clearly identifiable and included the dura, the lig. flavum, the lig. long. posterior, spinal nerves, small pieces of disc material and various fibrous bands. The usefulness of the biopsy forceps was also shown.

[Percutaneous vertebral augmentation (PVA) in osteoporosis of the vertebrae--an experimental study]. / Perkutane vertebrale Augmentation (PVA) bei osteoporotischen Wirbelkörpern--eine experimentelle Unterschung.

The present study was conducted with the aim of establishing whether minimally invasive percutaneous techniques used to stabilize osteoporotic vertebrae are technically feasible. Two different methods were investigated in human thoracolumbar cadaveric vertebrae. In the first technique, special titanium implants were placed via a postero-lateral approach. With the second method, the vertebrae were filled with different types of cement of different viscosities. After each procedure, the vertebrae were examined with conventional X-ray and CT scans. The first technique proved quite unsuccessful--the insertion of the titanium implants proving difficult despite the use of special instruments. The results achieved with the second method were much better. The use of low-viscosity bone cement produced the best results. Despite a single lateral point of entry, the vertebrae were almost completely filled right into the contralateral side. Lumbar vertebrae required an average volume of cement of 7 ml (range: 6.5-10 ml) and thoracic vertebrae 5.5 ml (range: 4-7 ml). Specially developed cement application devices made possible problem-free, controlled introduction of the cement.

[Design features of an individual thrust plate prosthesis]. / Konstruktionsmöglichkeiten einer Individuellen Druckscheibenprothese (I-DSP).

The purpose of the present study was to document the osteotomy plane for the thrust plate prosthesis, and to evaluate the question whether the geometry of the thrust plate itself correlates with the range of motion after implantation and whether the osteointegration area can be optimised. For the first part of the study, the two-dimensional geometry of the osteotomy was demonstrated in 12 computer-reconstructed femurs after performing a virtual cut at a CCD angle of 135 degrees. In the second part we constructed a prototype of an I-TPP with an optimised thrust plate and corpus geometry. In a final step, we documented the range of motion with computer-aided movement mapping. The results showed a wide variance in osteotomy geometry in the 12 femurs. With the I-TAP we were able to obtain a much better surface adaptation of the thrust plate. Movement mapping showed a much lower range of motion in the I-TPP implant.