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K Draenert

Publications and source records attributed to K Draenert.

At least 19 recordsLinked to original sources
PubMed1999

[A new experimental model for repetitive osseous blood supply measurement].

The aim of this study was to establish a novel model permitting repetitive analysis of osseous perfusion over a period of 33 days using the fluorescent microsphere technique. After implantation of two port systems into the right and left carotid artery in New Zealand rabbits (n = 3), fluorescent microspheres were injected into the left ventricle, while blood samples for reference probes were taken from the descending aorta. Using seven different fluorescently labeled microspheres, injections were repeatedly performed starting 3 days after implantation (t = 0) at days 1, 3, 5, 12, 19, 26, and 33. Osseous blood flow was semiquantitatively analyzed by counting the number of trapped microspheres within the bone sections performed through the distal femur condyle (n = 8) using a fluorescence microscope. Over the entire observation period of 33 days, intraindividual variance in the number of trapped microspheres was low while there were marked interindividual differences between animals. The mean osseous perfusion in the three animals evaluated so far remained constant over the observation period of 33 days. The present model is the first to allow repetitive analysis of osseous perfusion over an observation period of 33 days. Using this model, the role of regional osseous perfusion can be studied under conditions such as impaired bone healing following radiotherapy- and/or chemotherapy, implantation of biomaterials, and transplantation of bone.

Animals↗
PubMed1998

The John Charnley Award. Prophylaxis of fat and bone marrow embolism in cemented total hip arthroplasty.

The efficiency of a new cementing technique developed to prevent the risk of intraoperative pulmonary embolism was assessed. Seventy patients with coxarthrosis entered into a prospective, randomized clinical trial. In the control group of 35 cases the total hip replacement was cemented conventionally. In the second group a proximal drainage placed along the Linea aspera, and a distal drainage placed in the diaphysis, created a vacuum in the medullary cavity of the femur during the insertion of the stem. The operation was performed with the patient under blood gas analysis and hemodynamic and transesophageal echocardiography monitoring. Severe transatrial embolic events were observed during the insertion of the femoral component in 94% of the cases of the control group and in 14% of the cases of the vacuum group; the difference is statistically significant. A significant decrease of arterial partial pressure of O2 (-40.8 mm Hg) and increase of the pulmonary shunt values (+28.3%) occurred 5 minutes after the observation of embolic events in the cases operated on conventionally, but these parameters showed minimal changes in the vacuum group. The rise of intramedullary pressure in the femur is the most decisive pathogenic factor of pulmonary embolism during total hip arthroplasty. The logical prophylactic measure to prevent intravasation of fat and bone marrow is to create sufficient drainage. The cohorted investigation showed the value of the vacuum cementing technique for a substantial reduction of intraoperative embolism and pulmonary impairment.

Aged↗
PubMed1995

Biological effects of shock waves: in vivo effect of high energy pulses on rabbit bone.

Extracorporeal shock waves have recently been introduced to treat pseudarthrosis and aseptic bone necrosis. Only little information exists up to now about the morphological effects of shock waves on normal bone. To study both their acute effect on bone and their long-term effect on its remodelling, 1500 shock waves generated with a Dornier XL1 experimental electrohydraulic lithotripter were applied at 27.5 kV to 19 rabbits divided into five groups. Changes were evaluated after 6, 11, 41, 59 and 85 days. The discharges were focused to the right femur 1 cm above the knee joint. Bone remodelling was assessed in four groups by four-colour fluorescent labelling with labels administered sequentially over 8-day periods during the first month after shock-wave application. Radiographs were taken at dissection to detect fractures. As a result, shock waves were found to induce periosteal detachment with subperiosteal haemorrhages and to press marrow contents out of the medullary cavity. In the medullary cavity, diffuse haemorrhages, haematomas and foci of fractured and displaced bony trabeculae were found. The bone cortex and the knee joint were normal. Radiographs showed lucencies in the marrow but no fractures. During the weeks following shock-wave application, there was intense apposition of new cortical bone resulting in considerable cortical thickening while trabecular remodelling in the medullary cavity was only minor. The displacement of bony trabeculae and marrow contents point to the action of cavitation as the major mechanism of shockwave damage to bone.

Animals↗
PubMed1995

[The significance of blood vessels on both sides of the growth plate].

A new 3-D presentation of the whole vasculature of the epiphyseal growth plate clearly allows for a distinction between arterial and venous sections of the blood circulation. Histological investigations using these processing methods could neither prove the connection between epiphyseal and metaphyseal vessels through the growth plate in newborns nor the concept of an arterial epiphyseal blood supply of the growth plate presented by Trueta. It is rather a question of an arterial metaphyseal perfusion and an epiphyseal venous drainage system.

Animals↗
PubMed1989

Modern cementing techniques. An experimental study of vacuum insertion of bone cement.

The results of these experiments show that an increase in the intramedullary pressure (IMP) can lead to embolization of bone marrow contents via the venous drainage system along the linea aspera. A vacuum applied distally to the medullary canal is very effective for filling the diaphyseal tube with cement. The cancellous bone honeycombs of the proximal metaphysis, however, can only be filled if the bone sponge is tunneled at the level of the femoral calcar; a proximal vacuum then yields filling of the cancellous bone framework with bone cement. In order to fill the weight-bearing spongious framework of the pelvic bone with cement, the acetabular cavity should be sealed with a rubber ring and vacuum applied proximo-laterally to the ilium, thereby giving an extremely high suction pressure.

Animals↗
PubMed1985

The role of the vessels in the growth plate: morphological examination.

Combined methods of light microscopy to present ossification zones by means of fluorochrome dyes make it possible to explain the contradicting presentations of the vascular system of the growth plate in the literature. The vascular system was casted with methacrylates which can be presented in the scanning electron microscope 3-dimensionally together with the trabeculae as a result of their resistance in the electron beam. The 3-dimensional presentation in the electron microscope allows a clear distinction between the various vascular sections in the arterial flow system. In the microcorrosion casts the vessels of the epiphyseal side of the growth plate can be clearly distinguished from those of the metaphyseal side. The combination of both methods: labelling with fluorochromes investigated in the incident fluorescent light and casting of the vessels studied in the SEM shows close connection between the arterial vascularization and osteogenesis. These findings also explain the reactions on the part of growth behavior following traumatic injuries to the growth plate - reactions which could not be clearly explained up until now. Our findings do not contradict results of studies in the literature. They permit a uniform interpretation of these findings, however. Presentations of the venous drainage system on the epiphyseal side of the growth zone have not been made to date.

Animals↗
PubMed1983

Studying bone regeneration with the scanning electron microscope.

The interest in bone structure is very old. That is shown in a historical review with special regard to bone fractures and gap healing. The three-dimensional architecture of the supporting tissue corresponds to the strain acting on it. This can only be presented clearly in the SEM, especially by stereoscopical documentation. Three aspects of utmost importance when studying bone formation were taken into consideration: the three-dimensional presentation of the trabeculae, the processing of the vascular system together with the bony trabeculae, and the preservation of the cells and fibres in their natural state which is only guaranteed in a non-dehydrated frozen state. Reliable bone histology requires the preparation of non-decalcified specimens which are processed for light microscopy. Labeling newly formed bone with fluorochromes is a very common method to analyse sequences of bone formation. Studying the same specimens using both fluorescence microscopy and the SEM provides information not obtained using one method alone. Fresh specimens can be processed for the SEM following light microscopical documentation especially in incident fluorescent light; embedded blocks used for light microscopical investigations can also give valuable information in the SEM when the resin has been removed. The combination of the different methods is of special interest for orthopaedic basic research.

Animals↗
PubMed1983

Adherence and growth of bacteria on bone cement in vitro and in chronologically infected artificial joints.

Low grade infections following total hip replacements manifest themselves late after surgery. These infections seem to be sterile; there are major problems in identifying the causative organism by cultivation. SEM investigation of small samples of the bone cement, the task of which is to anchor the prosthesis in the bone, is a suitable method for identifying the bacterial origin of these infections. During conventional histological preparation polymethacrylates are dissolved. Freeze-drying techniques, however, allow the preparation of bone cement samples for the SEM. The growth of staphylococci on cement particles shows that these resins can no longer be considered biologically inert. The surface is attacked by the bacteria.

Bone Cements↗
PubMed1982

Ice crystal damage in freeze-dried articular cartilage studied by scanning electron microscopy.

The aim of preparing specimens at very low temperatures is to maintain biological tissue in its natural state. The problems which arise are: 1) obtaining the highest possible cooling rate when freezing the tissue; 2) preventing melting with recrystallization during the drying process; and 3) preventing the dried specimens from water vapor contamination. Biological tissue is prepared in a cooling chain by freezing the samples in a supercooled nitrogen bath, breaking the specimens in the frozen state, sputtering the fracture surfaces in a vacuum on the cooling stage of a special device and then transferring the specimens under vacuum to the SEM where they are studied on a cooling stage. They have smooth surfaces, with the liquid and solid phases present simultaneously, and no artefacts. Any shifts or deformations which may occur within the structure cannot yet be determined. Freeze-drying quenched specimens at various temperatures (-140 degrees to -60 degrees C) taking the dynamics of vapor pressure into consideration shows that sublimation, the melting processes with recrystallization and the resulting damage to the structures occur simultaneously during the drying process. The destruction of the tissue is inversely proportional to the ratio of sublimation to melting.

Animals↗
PubMed1980

Gap healing of compact bone.

Standard-sized holes were drilled in the tibia of rats resulting in a reproducible model which can be used to study the different stages of gap healing where practically no influence from biomechanical forces is present. Primary bone healing takes place in holes up to a diameter of 800 micrometer. In this case, no differentiated cartilage or connective tissue is formed. The medullary cavity is closed by a sealing callus. The bony splinters resulting from the operation are incorporated into the osseous framework. Revascularization results from the formation of medullary sinus which grows into the hole. The periosteal osseous depositions are supplied by the nutrient vessels, too. The centrifugal arterial bloodstream and the centripetal venous backflow are maintained under stress conditions during gap healing. Our investigations showed that after ten days drill holes in compact bone had been two-thirds filled from the medullary canal. At this point, the periosteal new bone formation had not yet reached the edge of the hole. The medullary sinus system in the medullary canal is different from the periosteal vascular network in that the former displays vessels with a regularly developed framework.

Animals↗
PubMed1980

The vascular system of bone marrow.

Not only the arterial, but also the low pressure system of the bone marrow can be demonstrated by micro-corrosion casts using resins of low viscosity. Vascular bone specimen are obtained by injection of self-curing resin and through subsequent maceration. The three-dimensional representation of the vascular pattern in bone marrow in the scanning electron microscope (SEM) enriches the interpretation of morphology and function of the low pressure system. The nutrient arteries enter the medullary canal and then progress in a spiral form branching into the metaphysis. The arterioles arise from the smaller arteries, further divide into smaller arterial capillaries which then drain into sinusoids which were conically enlarged. The three-dimensional and often hexagonal arrangement of the vascular framework is very evident. Increasing in width the marrow sinusoids drain into wider veins and lastly into the central venous canal. Apart from these medullary sinusoids, finely calibered thin-walled venous capillaries in a regularly anastomosing network can be found as an indication that the wide medullary sinusoids are to be considered as a functional state of active bone marrow.

Animals↗
PubMed1980

[Morphology and clinical aspect of the lateral ligaments of the ankle joint (author's transl)].

The direction of movement and the range of movement of a joint are determined by the lengths of the ligaments and the positions of their origins and insertions. It follows that any operation which alters the length of a ligament or moves one of its points of attachment is unphysiological. Reconstruction should be carried out with due regard to the normal anatomy. In the ankle joint, for example, the tip of the lateral malleolus should be left free of ligamentary insertions. Until now, anatomical illustrations have shown the lateral ligaments of the ankle joint to be attached to the anterior border of the fibula and to its anterior and lateral surface. All the older illustrations emphasize a band of fibers which passes directly from the neck of the talus to the calcaeus. This band varies in thickness and always forms the base of the triangle formed by the anterior talofibular ligament and the calcaneofibular ligament. Examination of surgical specimens and amputated ankle joints shows that the lateral tip of the fibula is free of ligamentary insertions. The lateral fibular ligaments are attached to the distal end of the fibula around the border of the cartilaginous foint surface. The only fibers which are derived from the lateral surface are those from the periosteum. This fact is of considerable importance in reconstructive surgery of the ankle joint, since strong ligamentary insertions which surround the lateral surface of the fibula necessarily oppose rotation or screw-like movement of the fibula about its longitudinal axis.

Adult↗
PubMed1979

[Arthroplasty of the upper ankle joint. Possibilities and limitations].

It is out of the question that alloarthroplasty of the upper angle joint must today belong to the therapeutic repertoire of the orthopedic surgeon. The anatomical situation of the upper ankle joint brings considerable problems for the total replacement and then also for the surface replacement. At the time being models are already available, which, seen on the whole, have already brought quite reliable results. Requirement for the success of the operation is the technically perfect insertion of the surface replacement or of the total joint and furthermore the insertion of the replacement under appropriate conditions, whereby the operation in an aseptive room ("Reinraum") has proven itself effective also on the upper ankle joint.

Air Pollution↗
PubMed1978

[Histomorphology of the bone-cement contact. Experimental phenomenology of the osseous reconstruction processes. I].

In animal experiments the femurs of 25 rabbits were filled with bone cement. In cross sections of the diaphysis even after only one week, small gaps were found filled by lamellar formation of new bone. Osteoblast layers directly on the cement surface were also observed. After 4 to 6 weeks there was a circularly closed contact of inner lamellae and after 9 months a secondary medullary cavity was formed. At this time there was formed a trabcular contact with the implant, interrupted by medullary spaces full of cells. Sometimes woven-bone formations were found in the bone-cement interface.

Animals↗