Biomedical subjects

M Runkel

Publications and source records attributed to M Runkel.

At least 37 records · Page 2Linked to original sources

PubMed1995

[Is there a connection between intramedullary pressure increase, bone marrow intravasation and deep venous thrombosis of the leg in endoprosthetics?].

Deep vein thrombosis still is a severe problem in hip replacement. Based on pathophysiological considerations, it is postulated that there is a connection between intramedullary pressure peaks, resulting intravasation of bone marrow, and the induction of deep vein thrombosis. The content of the bone marrow cavity can be considered active where coagulation is concerned. Intravasation may contribute to the development of deep vein thrombosis. In addition to medicamentous prophylaxis and early mobilization, a surgical technique also helps in the prophylaxis thrombosis. In this technique, intramedullary pressure increases are avoided as far as possible, which consequently minimizes intravasation of the content of the bone marrow cavity.

Aged↗

PubMed1995

[The effect of bone marrow embolization on the choice of procedure in the stabilization of femoral fractures].

Because of an extended venous drainage system, especially in the supracondylar area, a pressure increase in the femoral cavity results in embolization of the contents of the bone marrow cavity. Bone marrow embolization alone is mostly not apparent clinically but together with cofactors it may result in severe pulmonary damage and occasionally even in death. Cofactors are volume deficit, shock, thoracic and polytrauma and preexisting pulmonary disease. In the field of traumatology a pressure increase in the femoral cavity regularly occurs during unavoidable movement of femoral fragments in traction, during reduction, intraoperatively during intramedullary nailing, and in hip replacement. A hematoma acts as a hydraulic transmitter. Early osteosynthesis within 24 h avoids permanent intravasation of moderate amounts of the contents of the bone marrow cavity. Concerning intramedullary nailing, there are considerable differences between reamed and unreamed nailing. Reaming always leads to high-pressure increases in the femoral cavity, resulting in embolization. Therefore, reaming should not be performed if cofactors of manifestation of pulmonary impairment are present. Unreamed nailing results in less intravasation, but is not entirely harmless, as considerable pressure increases occur in unreamed nailing as well. The gap between the nail and the entrance of the distal fragment is the decisive parameter. Not just the smaller intravasation of bone marrow during unreamed nailing is important. After each reaming process, the bone marrow cavity rapidly refills with blood, which is activated concerning coagulation and pressed into the circulation during the following reaming process. Because of superior bone healing, interlocking nailing is the treatment of choice in diaphysial femoral fractures. As far as the differential indications of reaming are concerned, the discussion is not yet closed. However, reaming should undoubtedly be restricted to a few reaming processes. Before unreamed femoral nailing, the width of the bone marrow cavity must be examined exactly. If the width of the bone marrow cavity, the patient's condition and experience of the surgeon allow unreamed nailing, this procedure can be recommended. As the venous drainage system of the tibia is not important compared to the femur, the question of reaming or not in tibial fractures is not influenced by the danger of embolization, but by soft tissue damage and the stability of interlocking bolts. In patients with femoral fractures and co-factors for the manifestation of pulmonary impairment, the choice of osteosynthesis type should take plating in its improved form into consideration, as this preserves the vascularity of the fragments.(ABSTRACT TRUNCATED AT 400 WORDS)

Bone Marrow↗

PubMed1994

[Results of implantation of uncemented porous metal hip prostheses].

72 patients having cementless spongy-metal hip prosthesis were reexamined by clinical and radiological check up two to seven years after implantation (average 43 months). In case of five patients hip prosthesis had to be changed due to loosening (no bony ingrowth n = 2, loosening of acetabular component due to technical faults n = 3). In correlation to clinical results 88% could be considered as excellent or good, 9% acceptable and 3% as inadequate. 10% of the patients complained about thigh pain. The typical radiological bony reactions of the surrounding bone are described. An evaluation of the radiological results can only be done under consideration of the clinical problems involved. In view of the positive results obtained in the recent time the use of spongy-metal hip prosthesis can be recommended for cementless hip joint replacement in case of younger patients. Especially in case of cemented hip joints which have become loose it will be an advantage to use spongy-metal hip prosthesis.

Adult↗

PubMed1994

[Application possibilities of MR arthrography in diseases of the shoulder joint].

In a prospective study possible indications for MR arthrography of the shoulder were evaluated. 37 patients were examined before and after intraarticular administration of a 2-mmolar solution of Gd-DTPA. MR arthrography was performed if there was no joint effusion and/or an uncertain finding concerning the rotator cuff or the capsulolabral complex on plain MR images. MR arthrography leads to a better demonstration of labrum pathology in 11/22 patients and to a superior delineation of the capsuloligamentous apparatus in 20/22 cases. In 9/15 patients with impingement lesions MR arthrography allowed a differentiation of severe tendinitis from partial and small full-thickness tears of the rotator cuff. MR arthrography of the shoulder joint enhances the accuracy of MR in case of an uncertain finding on plain MR images.

Adolescent↗

PubMed1994

[Possibility for detecting HIV-1 in bone transplant by PCR using the HIV-1 microtiter plate assay].

It is known that HIV can be transmitted by allogenous bone transplantation. Hitherto neither chemical nor physical methods have existed to allow reliable disinfection and sterilization of bone specimens without reducing osteogenetic potency. Only demonstration or exclusion of the presence of HIV-1 in a bone specimen guarantees that infection will not occur. The method now presented for HIV detection is based on a polymerase chain reaction (PCR). This HIV microtiter-plate assay combines amplification of DNA molecules with a staining reaction. In cultures containing HIV-infected cells definite detection of viruses was possible when 50-100 cells per specimen were infected. Examination of 137 HIV-negative and 25 HIV-positive bone specimens showed sensitivity of 96% and specificity of 97.8% for the test. In subsequent studies, after drying on filter paper viral DNA was again demonstrable by the PCR. This means safe handling and uncomplicated transportation of non-infectious specimens to a central analysis laboratory are possible. This HIV test offers the possibility of quick and safe demonstration that specimens are free of HIV and is therefore likely to enhance the safety of bone transplantation considerably.

Bone Transplantation↗

PubMed1994

[Bone remodeling after reamed and unreamed intramedullary nailing. A histomorphometric study].

Experimental findings after unreamed nailing have indicated certain advantages for new bone formation in comparison to reamed nailing. It would be of interest to establish whether any essential differences can be determined in the extent and course of callus formation. To investigate this question, thin sections of bone from 16 tibiae (nailing after transverse osteotomy in sheep) were examined histomorphometrically the progress at the periosteal and interfragmentary surfaces of the remodelling callus being recorded separately after 4, 6 and 8 weeks. After unreamed nailing, more extensive and earlier formation of interfragmentary callus was observed. At 4 weeks postoperatively the remodelled periosteal bone surface was 158 mm2, which was 1.6 times that after the unreamed procedure (95 mm2). By 4 weeks after unreamed nailing the periosteal callus surface was already greater than 6 weeks after reamed nailing. On the basis of these experimental results the use of unreamed nailing can be recommended, especially for open fractures and fractures with severe soft tissue damage.

Animals↗

PubMed1994

[2- to 7-year results of cement-free and cemented joint replacement in femoral neck fractures and coxarthrosis].

In 43 patients with cementless and 43 patients with cemented hip prosthesis (S+G hip system) a clinical and radiological follow up was performed 2-7 years after total hip replacement. In average the follow up period was 43 or 48 months. We found good or excellent results in 88% after cementless and 95% after cemented fixation. The results after cementless hip replacement were caused by loosening in the early postoperative period in 3 cases and more frequently thigh pain. In conclusion of our results and the expected later results after 10 years follow up we prefer the cementless fixation in patients under 60 years and cemented fixation in the group over 70 years. Patients between 60 and 70 years seems to benefit from a fixation with an cementless acetabular component and an cemented stem (hybrid prosthesis).

Adult↗

PubMed1994

[Rotational stability of the thoracolumbar spine after interlaminar ultrasound window, hemilaminectomy and laminectomy. A comparative experimental study].

Intraoperative spinal sonography to check whether fragments have been successfully repositioned requires enlargement of the natural interlaminar window to 8 x 10 mm. The present study was performed to measure any rotational instability caused by such a laminotomy and compare it with that resulting when the conventional methods of checking the spinal canal, e.g. hemilaminectomy and laminectomy, are applied. The investigations were carried out in 10 human vertebral columns, in the area of T-12, L-2 and L-4. Torsional loads of up to 20 Nm were applied to the spines and axial rotations were recorded. Laminotomy, hemilaminectomy and laminectomy were done step by step. The loading-unloading cycles were achieved with initial axial rotation and decreasing torsional moment after measurement the dorsal manipulations. It was shown that interlaminar fenestration causes a hardly measurable instability. A laminotomy to 10 x 20 mm, allowing direct repositioning of the posterior vertebral surface, causes a 6% loss of stability. A significant decrease is caused by hemilaminectomy, with a 20% loss and by laminectomy, with 27% loss of rotational stability compared with the intact spine. Rotational instability of the spine causes severe pain and often has to be treated by spondylodesis. The present investigations show that the spinal canal should not be checked by hemilaminectomy or laminectomy. For this we now use intraoperative ultrasound.

Biomechanical Phenomena↗

PubMed1994

[Bone healing after unreamed intramedullary nailing].

Good clinical results of unreamed nailing have been observed primarily in cases of open fracture. However, it is still unclear whether unreamed nailing is a suitable procedure for fractures that have previously been treated with reamed nailing. Since histological findings on bone healing after unreamed nailing were not available, an animal experiment on sheep was undertaken. The aim was to investigate whether there were differences in the nature of bone healing following reamed and unreamed nailing procedures. Fluorescence microscopy clearly showed that maximal callus formation occurred within 4 weeks after unreamed nailing and within 6 weeks after reamed nailing. Callus formation was also more prolific after unreamed than after reamed nailing. It was demonstrated by microradiography that bone regeneration progressed more rapidly, in terms of both periosteal and interfragmentary callus, after unreamed nailing. No disturbances of bone healing and no greater risk of pseudarthrosis were observed following unreamed nailing. Histological investigations showed that bone healing was faster after unreamed nailing and there was a reduced loss of vitality. This is of particular clinical relevance in the surgical treatment of fractures with severe soft tissue injury and of open and comminuted fractures. These results indicate that an extension of the indications for unreamed nailing should be considered.

Animals↗

PubMed1994

[Technique of plate osteosynthesis of the femur].

When plating is performed for fixation of complex femoral fractures the need for medial buttress to give durable weight-bearing ability of the bone is mandatory. However the means of achieving this is controversial. Many authors are in favour of mechanical reconstruction of the medial buttress, if necessary with a bone graft. Alternatively, medial buttress can be achieved by means of a technique allowing biological fracture healing, which is only possible, when the vascularity of all fragments is preserved. In 39 cases of osteosynthesis with plates for complex femoral fractures the bridging technique was used at surgery, to avoid denudation of the fragments. All osteosyntheses were performed without the application of bone clamps. After minimal exposure of the femur at the lateral side only, the plates were fixed in the main proximal fragment with one screw, in the case of blade plates the blade was fixed without bone clamps too. Afterwards the main distal fragment was drawn up to the plate and fixed directly and with a screw. In 9 cases the plates were inserted behind the vastus lateralis muscle, preserving its continuity, and fixed distally with another screw. After fine checking of the fracture alignment for rotation and length the plates were fixed with four or five screws in each main fragment, all at sites distant from the fracture. Meanwhile, all 39 fractures have consolidated. There were no cases of infection. Bone grafting was necessary in 8 cases. Only in 2 cases were the defects located in the medial area. In 37 of the 39 osteosyntheses an excellent medial buttress was achieved by bone healing.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Plates↗

PubMed1993

Pathogenesis and prophylaxis of circulatory reactions during total hip replacement.

Circulatory reactions such as a drop in blood pressure, bradycardia, cardiac arrest, and even intraoperative death after insertion of the stem are well known events during total hip replacement. The present paper reports bone marrow intravasation after rise of intramedullary pressure in the femoral cavity during insertion of hip prostheses, demonstrated by intraoperative transesophageal echocardiography. In an animal study, the ultrasound echoes were identified as "mixed emboli" consisting of a core of bone marrow surrounded by thrombus. These results suggested the use of an intramedullary plug to restrict the intravasation of bone marrow. A trial was undertaken in 60 total hip replacement operations. The first 30 were performed using the conventional technique without an intramedullary plug. In a second series of 30 operations, an intramedullary plug made of cancellous bone taken from the resected femoral head was placed 2 cm below the expected location of the tip of the stem. The cement was applied from distal to proximal by syringe. After implantation of the prosthesis using the conventional technique, a significant drop in blood pressure was observed. In the second series, the drop in blood pressure did not occur. In conclusion, it was demonstrated that effective venting of the bone marrow cavity by a bore hole, and avoidance of compression of the bone-marrow-filled distal femoral cavity by using a plug, results in effective prevention of circulatory reactions: no drop in blood pressure occurred. The use of an intramedullary plug is discussed and recommended.

Aged↗

PubMed1993

[Experimental studies in weakening the stability of the trochanter major by lateral fenestration].

A major disadvantage of the usual 130 degree angle plates when handling the fracture of the neck of the femur is the fact that the lateral corticalis of the femur is almost completely interrupted by the broad window at a biomechanical important and highly strained location. This often leads to the complications such as the breaking off of the greater trochanter or lack of stability etc. The experiment examines ten pairs of human femora for a decrease of stability, which results from the lateral fenestration for the osteosynthesis. One of the two bones out of a pair received a slit at a right angle concerning the axis of the femur, the other one a round hole. The slit was made into the proximal lateral femur as if preparing for the installation of a 130 degree angle plate. On the corresponding spot of the second bone a round hole was drilled. The remaining stability of the compact bone was measured by experimental pulling on the greater trochanter. Under the assumption that left and right femur have about the same stability, which was proven in one of the experiments, a significant disadvantage was found for the relatively wide slit.

Biomechanical Phenomena↗

PubMed1993

[Treatment and results of ruptures of the patellar tendon].

Ruptures of the patellar ligament are rather uncommon. In younger individuals they are due to adequate trauma, in older individuals spontaneous ruptures occur after inadequate trauma. We observed eight traumatic (mean = 26.5 years) and eleven spontaneous ruptures (mean = 57.5 years) between 1980 and 1990. There is no alternative to surgical repair of the ruptured or torn-out patellar ligament. Tendon-repair with supportive wire-looping and early functional physiotherapy produces a good functional result. The outcome of patients treated in this manner shows persisting slightly muscular atrophy of minor degree and limited knee mobility with only a little all-day handicap.

Adult↗

PubMed1993

Pathogenesis and clinical relevance of bone marrow embolism in medullary nailing--demonstrated by intraoperative echocardiography.

For the clarification of pulmonary impairment after medullary nailing of femoral fractures, the intramedullary pressure in the femoral cavity during the operative procedure was investigated. In addition, an intraoperative transoesophageal echocardiography was performed which revealed two phenomena occurring once the intramedullary pressure had increased: snow-flurry and configured emboli. An experimental study in sheep was performed in order to define the substrata of the sonographic echoes. The level of intrafemoral pressure which would result in bone marrow intravasation and the substrata of the echocardiographic echoes were studied in sheep by applying pressure to the femoral cavity. Sonography of the distal vena cava by laparotomy and macroscopic and histological investigation of the venous blood received throughout a proximal subdiaphragmal venotomy were undertaken. The intrafemoral pressure peaks correlated with the appearance of sonographic echoes in both patients and sheep. Snow-flurry is an indication of small amounts of bone marrow and already appears at an intramedullary pressure of 50 mmHg, which can easily occur during movement of non-stabilised fractures (values up to 90 mmHg were observed)--configured emboli consist of a core of bone marrow surrounded by thrombotic aggregate and only appeared at pressure increases of over 200 mmHg in the animal experiments. During medullary nailing in patients the intrafemoral pressure increases up to 200-600 mmHg in all reaming procedures. Configured emboli were seen in 8 of 20 patients being treated with reamed nailing. In five nailing procedures performed using the unreamed technique, no pressure increases greater than 70 mmHg and no configured emboli were observed. I.v. injected bone marrow results in pulmonary impairment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

[The value of the radiologic Lachman test in anterior cruciate ligament ruptures].

A radiologic Lachman test of both knees was performed in 35 patients with surgically verified tears of the anterior cruciate ligament (ACL). We found a mean anterior drawer of 3.2 mm for uninjured joints, 4.5 mm for isolated ACL-tears and 10.8 mm for complex ACL-injuries. Sensitivity of the radiological Lachman test was 95% for complex ACL-injuries as only 23% in case of isolated ACL-ruptures. Failure of diagnosis due to clinical investigation in case of ACL-ruptures could not be proved by means of radiological Lachman-test. Technical requirements and radiation exposure are further disadvantages. Clinically doubtful cases of acute knee injuries should therefore be investigated with other diagnostic procedures.

Adolescent↗

PubMed1993

[Detection of primarily unrecognized fractures in severely injured patients by skeletal scintigraphy].

Even in despite of diligent investigation clinical and radiological diagnostics can leave fractures unrecognized in seriously injured patients. Bone-scans of 53 patients revealed 68 additional fractures. In 45% of all cases the initial diagnosis was altered, 19% resulted in therapeutical consequences. Routine diagnostics should be supplemented by a bone-scan if clinical and radiological findings are not in line. A bone-scan can exclude any osseous lesion and can survey the full extent of injuries especially in the disoriented or unconscious patient.

Adolescent↗

PubMed1993

[Development of thromboses in hip joint endoprostheses. A study with color-coded duplex ultrasound].

After 102 hip replacements in a surgical technique that avoids bone-marrow intravasation as much as possible, color-coded duplex sonography revealed thigh thrombi in only 4 cases without any signs of thrombosis. This rate is lower than that found in all other comparable studies. The investigations stress the role of bone-marrow intravasation in the induction of deep vein thrombosis in hip replacement. With an optimal surgical technique, thigh thrombi can be greatly reduced in hip replacements, which have a higher rate than all other operations.

Aged↗

PubMed1993

[Nuclear magnetic tomography in shoulder dislocation].

Sixty-two patients with anterior shoulder dislocations were examined by magnetic resonance imaging (MRI). After a primary dislocation, 30 patients showed 23 (77%) tears of the glenoid labrum, 13 (45%) anterior-inferior separation of the capsula, 24 (83%) Hill-Sachs lesions, 6 fractures of the greater tuberosity and 4 glenoid rim fractures. Thirty-two patients with recurrent shoulder dislocation had 14 (44%) tears and 15 (47%) defects of the glenoid labrum, 16 (50%) anterior-inferior separation of the capsula, 28 (88%) Hill-Sachs lesions and 3 glenoid rim fractures. MRI permits complete non-invasive documentation of glenohumeral instability if joint effusion is present. In the absence of joint effusion, diagnostic accuracy can be improved by application of a contrast medium.

Adolescent↗