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Biomedical subjects

J Koebke

Publications and source records attributed to J Koebke.

At least 73 records · Page 4Linked to original sources
PubMed1996

Accessory ossifications in the ulno-carpal wrist region.

Accessory ossifications in the ulno-carpal transition such as ossa styloidea or triangularia represent a rare finding, especially among younger individuals. The present results of radiological and morphological investigations show that up to 50% of the ossa are located palmar to the styloid process. Most of them have a sharply bordered contour and are less than 10 mm in length. An aetiological classification of accessory ossifications in the distal epiphyseal region is only possible when an obvious case history is available. Accessory skeletal elements are present among elderly individuals as a result of sclerotic alterations of the ulno-carpal joint elements. Among younger individuals, however, they point to a pathological aetiology and can therefore assume clinical and diagnostic relevance in cases involving inflammatory rheumatic and traumatic alterations accompanied by vague discomfort in the proximal wrist region.

Adult↗
PubMed1996

Histomorphology of the peritendinous tissue of the phalangeal extensor apparatus.

The phalangeal extensor tendon is surrounded and fixed by connective tissue showing differently extended expansions of its intercellular spaces. This connective tissue runs in horizontal lamellae and forms connective tissue spaces around the dorsal extensor apparatus. The clinical importance of the connective tissue spaces is in the formation of gliding spaces and the diffusion of phlegmonas or purulent infection processes. The morphological differentiation of the cellular and intercellular elements of the dorsal connective tissue lamellae shows that the peritendinous gliding spaces around the dorsal aponeurosis are bordered by synovia-like cellular and noncellular structures. Besides mast cells and histiocytes many cells are seen that show all signs of activated fibroblasts. They form small groups of cells. These cells produce a mucoid dense bordering lamella that is opposite to the collagenous fibers of the dorsal aponeurosis. The intercellular matrix has importance both in fixing and mobilizing the phalangeal extensor tendons in the sheathless parts of the phalangeal extensor tendon.

Aged↗
PubMed1996

Gasless videoendoscopic implantation of an aortobifemoral vascular prosthesis via a transperitoneal versus extraperitoneal approach: an experimental study.

PURPOSE: To report progress in the development of a new minimally invasive surgical technique for aortobifemoral grafting utilizing gasless videoendoscopy. METHODS: In an experimental study, aortobifemoral Dacron vascular prostheses were implanted in 20 human cadavers using videoendoscopic techniques in both transperitoneal and extraperitoneal approaches. Rather than inducing pneumoperitoneum, the abdominal wall was elevated with an electrically powered lifting system. RESULTS: Each approach was utilized in 10 cadavers for implantation of 20 aortobifemoral grafts under endoscopic guidance in a gasless field. Average operative time for transperitoneal approach was 3.8 hours (range 3.0 to 5.5), slightly less than the average 4.1 hours (range 3.0 to 6.0) for the extraperitoneal access. Both access routes provided adequate visualization of the operative field. CONCLUSIONS: Advantages of gasless endoscopy include the use of conventional instruments and the potential benefits associated with a minimally invasive approach. Optical magnification facilitates suturing of the femoral anastomosis, improves examination of the vascular walls, and allows a more accurate suturing technique.

Aorta, Abdominal↗
PubMed1995

Morphology of the dorsal phalangeal connective tissue body.

BACKGROUND: The connective tissue body of the dorsal finger is partitioned by multiple horizontal lamellae derived from expansions of intercellular spaces. These connective fibres are involved in providing gliding spaces for the extensor apparatus, and they formed spreading rooms of infection processes. METHODS: In order to describe the topographical histological and histochemical behavior of cellular and intercellular elements of the border lamellae of the dorsal aponeurosis of the fingers, a modified method of Epoxid resin embedding technique without pre-infiltration is used. RESULTS: The bordering elements of the connective tissue lamellae described in this investigation are especially well defined in the region of the dorsal aponeurosis. The morphological examinations show that both the expansions of the intercellular space as well as defined fibrocytic cellular elements function in a manner equivalent to a synovial membrane of tendon sheaths. CONCLUSIONS: Saving or reconstructing these structures appears to be of importance in preventing for adhesive disorders of finger motion following surgical intervention in this region.

Aged↗
PubMed1995

Fibrous architecture of the dorsal aponeurosis of the thumb.

BACKGROUND: The extensor apparatus of the thumb displays obvious structural variations in its proximo-distal expanse. Its associated tissue comes in close relation to the dorsal aponeurosis that have varying topographical relationships to the extensor apparatus of the thumb. This region is especially important as the location of pathological and repair processes. METHODS: In this anatomical study using a modified embedding technique a histological description of the fibrous architecture of the dorsal aponeurosis and the peritendinous connective tissue body of the thumb is presented. RESULTS: The dorsal connective tissue of the thumb forms different layers of collagen lamellae as a peritendinous system around the tendons of the long and short extensor tendons of the thumb. This peritendinous laminar system as the main part of the dorsal aponeurosis is connected with both the capsular and the retinacular ligaments of the thumb. CONCLUSIONS: It will be shown that the structural variations of the dorsal aponeurosis and peritendinous connective tissue are an expression of different topographical zones of stress along the lines of a balanced musculofibrous stabilization of the interphalangeal joint of the thumb. The expansions in the peritendinous intercellular space act as defined gliding spaces or clefts of the extensor apparatus.

Aged↗
PubMed1995

Internal fixation of the distal radius. A comparative, experimental study.

In a comparative, experimental examination of 60 human cadaver radii, the stability of various, widely used internal fixation procedures of a distal radius fracture loco typico using a dorsal wedge was determined. The use of 2.5-mm Kirschner wires (K-wires) delivered a 10% greater stability than 1.8-mm K-wires. The 2.7-mm polylactide rods achieved a slightly greater stability than 1.8-mm K-wires under accurate pinning conditions. Polylactide rods (35 mm length, 2 mm diameter) and polyglycolide rods (60 mm length, 2 mm diameter) proved to be 20% less solid than 1.8-mm K-wires and almost 45% less than plate fixation. The short polylactide pins, however, did not have enough hold in the proximal cortical bone. The 2.7-mm polylactide rods (60 mm length) complied with the stability prerequisites necessary for comparable substitution for K-wires in distal radius fractures.

Bone Nails↗
PubMed1995

Contrast improvement using color-coded radiographs of anatomic specimens.

Radiographs are used in a wide variety of musculoskeletal examinations. Special procedures are required to improve image quality. We report a new radiologic technique that uses monochromatic molybdenum K alpha-radiation together with secondary digital color-coding to produce well contrasted images of supporting tissue. In order to investigate the diagnostic capability of this approach we studied specimens of the intervertebral disc, harvested from cadavers undergoing chemonucleolysis following an injection of chymopapain. Radiographs of the specimen taken using a Mo X-ray tube with a zirconium filter were scanned into a computerised image-processing system and color-coded. This method improves resolution and contrast in the images and allows the differentiation of morphologic changes.

Adult↗
PubMed1995

[Whole organ plastination in otorhinolaryngology].

Total organ sections have proven to be useful in the evaluation of the clinical growth behavior of malignant tumors. However, histologic techniques using tissues embedded in celloidin or paraffin are difficult to produce and require extensive amounts of time. Total organ plastination is a method superior to the aforementioned techniques. The number of artefacts is also greatly reduced by avoiding the need for decalcification. After removal of fat and dehydration, specimens can be placed in epoxy resin. Following evacuation and hardening of specimens, parallel sections can be separated with a diamond wire saw for precision slicing, with section thicknesses ranging from several centimeters to as small as 40 microns. The loss in material caused by slicing is as little as 0.3 mm per section. A further benefit of this method is the relatively large amount of time saved. The entire procedure yielding complete plastinated specimens requires a time period of approximately 40 days. The plastinated specimens are transparent, odorless and fixed and are ideal for instructional and research purposes. Deplastination for the purpose of further diagnositic study is also achievable with a minimum of technical effort.

Epoxy Resins↗
PubMed1994

Functional morphology of the deep transverse metacarpal ligament.

The deep transverse metacarpal ligament extends in radio-ulnar direction between the palmar plates of the metacarpo-phalangeal joints of the second through fifth finger rays. Continuing along the path of the palmar plates, the ligament divides the spaces between the fingers at the metacarpo-phalangeal border into functional spaces bordered by the ligamentous apparatus of the metacarpophalangeal joint capsules and filled by blood-vessels, nerves and intrinsic hand muscles. Morphometric examinations of the deep transverse metacarpal ligament indicate a greater strain of the radial components between the index and middle finger in the transverse plane as well as an increased stressing of sagittal fiber plates connecting the extending apparatus with the deep transverse metacarpal ligament via the metacarpophalangeal force nucleus. Palmar, sagittally directed collagen fiber bundles representing a location of initial or recurrent connective tissue proliferation can be histologically demonstrated as a connection between peritendinous and perivascular connective tissue of the palmar interdigital space and the palmar aponeurosis.

Aged↗
PubMed1994

The function of discomuscular relationships in the human temporomandibular joint.

The aim of this morphological study was to investigate whether muscle tissue attaches directly to the discus articularis of the human temporomandibular joint (TMJ) and to indicate the probable significance of such attachments for the function of this articulation. The macroscopic and microscopic findings were derived from fixed and unfixed human TMJ of varying ages and genders, whereby the functional maturity of the masticatory apparatus was taken into consideration. To date, the results of this study show that aside from fibers originating from the superior venter of the m. pterygoideus lateralis, additional muscle or connective tissue fibers from the perimysium of the m. masseter insert to varying extent in the disc. The same is true for the m. temporalis, which is also directly connected to the disc via muscular or fibrous elements, or indirectly via fibers from the m. masseter. The insertion of the m. pterygoideus lateralis is always in the medial portion of the discus articularis and those of the mm. temporalis and masseter, respectively, in the middle and lateral portions of the disc. It is highly probable that a direct force transfer through the mm. temporalis and masseter to the articular disc takes place, and that these muscles contribute to the movement of the disc during jaw movement, whereas the size and form of the muscle insertions are subject to a great deal of individual variation. Differences were observed between immature and mature TMJ as well as between partly and fully toothed masticatory apparatuses.

Age Factors↗
PubMed1994

[Topology of the carpal tunnel in dynamic stress of the wrist joint].

Alterations of the spatial geometry of the carpal tunnel and its contents during dynamic stress situations of the wrist are of importance in clarifying morphological causes of a carpal tunnel syndrome. In order to demonstrate the changes occurring in the form of the carpal tunnel and the location of its contents during wrist movement, casts of the carpal tunnel were produced from the hands of cadavers in flexed and extended positions. The casts were then morphometrically analyzed and the movements of the median nerve and the flexor tendons were examined radiologically. The investigation showed that a delicate equilibrium exists between the capacity of the carpal tunnel--whose hourglass shape typically changes to suit dynamic stress situations--and the volume of its contents. Spatial processes extending from the carpal tunnel wall or emanating from the structures contained within the carpal tunnel may exceed the system's ability to compensate for extreme positioning of the wrist and thus induce compression symptoms of the median nerve.

Aged↗
PubMed1994

[Dorsal gliding and functional spaces of the metacarpophalangeal transition].

Although the relevance of capillary and gliding spaces of the back of the hand and the finger located dorsal to the extensor aponeurosis in the metacarpo-phalangeal region between the layers of the subdermal connective tissue is often emphasized clinically in inflammatory and acute traumatic occurrences, hardly any information has been published concerning the morphology of these spaces. By means of plastic-injection techniques, varying configurations of capillary spaces in the distal region of the dorsum manus of cadavers were found. The deep connective tissue spaces located dorsal to the extensor aponeurosis were shown to have proximal connections to the dorsal tendon sheaths of the carpus, whereas superficial gliding spaces tended to vary in their expanse depending on the subcutaneous and epifascial septa. The deep as well as the superficial capillary gliding spaces are adapted as mobilizing and limiting structures for the movements of the metacarpo-phalangeal joints and the various mechanical stresses of the skin of the back of the hand. A high degree of exactness in the reconstruction of the marginal elements of such functional spaces appears to be of special importance with regard to a total restoration of the functional capability of the metacarpo-phalangeal joint region.

Capillaries↗
PubMed1994

[Combined arthrosis manifestation of the radial wrist joint].

In the following study, the basal joint of the thumb and its neighboring joints of 100 anatomical specimens were inspected radiologically and macroscopically for arthrotic alterations. The comparison of the radiological and macroscopic findings showed that early arthrotic joint alterations cannot be diagnosed by radiograms. Virtually half of the specimens examined demonstrated arthrotic lesions of the basal joint of the thumb, whereas the trapezio-scaphoidal and trapezoido-scaphoidal joints were only affected in one-third of the specimens. Two-thirds of the cases with manifest arthrosis of the metacarpophalangeal joint of the thumb demonstrated additional arthrotic changes in the joints between the scaphoid, trapezium, and trapezoideum. No macroscopic evidence of arthrotic alterations in the remaining radial carpal bones were observed. The architecture of the capsular and ligamentous apparatus as well as the individual variations in the scaphoid bone have both been discussed as possible causes of these phenomena, as were polyarthrotic or secondary arthrotic processes.

Adult↗
PubMed1993

Meniscal healing: a histological study in rabbits.

Repair of meniscal tears occurs best in the region of the capsular attachment. The further the tear from the site of capsular attachment, the less the vascularity, and healing becomes dubious. For an evaluation of healing in the poorly vascularised zone of the meniscus a histological study was performed in rabbits with standard longitudinal incisions in the posterior horn of the left medial menisci. In addition a biomechanical investigation of scar strength was performed. Three groups of animals were studied: group 1 were allowed to heal spontaneously, group 2 were sutured and group 3 were treated with fibrin glue. After 6 weeks, macroscopically, 4 out of the 10 menisci in groups 1 and 3 exhibited incomplete scar formation, whereas all menisci in group 2 looked well. This result fell short of statistical significance because 2 menisci in group 2 had to be excluded due to faulty localisation of the standard injury. In all groups the scars contained fundamental elements of healing, such as fibroblasts, blood vessels and fibrous material. Repair seemed to be significantly influenced by the proliferating synovial membrane. Histologically there was no difference between group 1 and 3. In both groups the lesions were filled with a broad strip of reparative tissue mostly consisting of plexiform collagenous fibres. Although the appearance of the menisci in group 2 was similar, the scar tissue was distinctly thinner due to the close adaptation of the wound margins, and the vascularity seemed better. In all specimens the tissue located towards the free rim of the meniscus showed signs of degeneration.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Densitometric analysis of the paranasal sinuses.

The knowledge of weak points in the osseous structure of the skull is of great importance for endonasal operations. For this reason the anatomy of the skull is accurately described in serial sections. Serial sections of 1.5 mm thickness are evaluated by a computerized image analyzing system, which allows qualitative as well as quantitative statements on the structure of the paranasal sinuses and their neighbourhood. The bone density in the frontobasal area of the skull as well as of the ethmoid cells is presented separately. The anatomy of the sphenoid sinus is described by densitometric and gross techniques.

Absorptiometry, Photon↗
PubMed1993

Radiolucent lines in total trapeziometacarpal joint replacement. A morphological and functional study.

The first metacarpal bone is stressed by a dorsopalmar bending, as proved by radiological studies. In case of a trapeziometacarpal arthrosis the subluxated metacarpal bone is subjected to an increased bending stress. Functional adaptation of the bone leads to an augmented cortical thickness. The dorsopalmar diameter of the medullary cavity decreases. After the implantation of the prosthesis the magnitude of bending stress again decreases and bony resorption occurs. This explains the radiolucent lines at the bone-cement interface of the metacarpal component.

Adult↗
PubMed1993

Monochromatic x-ray radiation for high resolution radiography in osteology.

The contrast of an x-ray exposure is influenced by the x-ray absorption of the examined material and the x-ray frequency. The examination of the absorbing properties of bone material in the molybdenum spectrum by means of the Bragg-method revealed an intense increase of absorption in the long-wave range. By using a zirconium filter, long-wave and monochromatic MoK alpha-rays can be isolated from the spectrum of a molybdenum x-ray tube. The x-ray exposures of thin bone tissue produced in this spectral range show a much greater degree of contrast and depth as compared to conventional exposures.

Alpha Particles↗