Biomedical subjects

K Wenda

Publications and source records attributed to K Wenda.

At least 37 records · Page 2Linked to original sources

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

[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

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

[Therapy of burst ceramic head of a hip prosthesis].

The therapeutical possibilities in case of fracture of a ceramic head ball of a hip prosthesis system are discussed. A seventy year old patient suffered a fracture of a ceramic ball of a cemented hip prosthesis with polyethylene cup, ceramic ball and metal stem without trauma after one year after implantation. During operative revision a marked destruction of the gliding plane of the polyethylene cup by craters and an extreme metallose because of wear of the metal conus far into the bone bed of the acetabulum was found. The reason for the very seldom occurring fracture of the ceramic ball are minimal differences in the ascent grade of the metal conus of the stem and the corresponding connection of the ceramic ball. The broken ceramic ball should be substituted by a metal ball.

Aged↗

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

[Reposition of fragments of the posterior surface of the vertebral edge with intraoperative ultrasound guidance].

The question of whether fragments of the posterior vertebral surface have to be removed in every case remains to be answered. Nevertheless, in many cases it is important to establish the situation inside the spinal canal intraoperatively. To this end we have used intraoperative ultrasound in 21 cases. The results have always corresponded closely with the findings of preoperative and postoperative computed tomography. Under the influence of this method we have modified our operative procedure. The technique of intraoperative ultrasound and our current operative practice are described in the present paper. We use typical cases to show that intraoperative ultrasound of the spinal canal is a very useful technique for several reasons: Accurate depiction of the spinal canal is always possible without destabilizing the dorsal vertebral structures. The risks and disadvantages of intraoperative myelography are avoided. The method is easy and can be repeated as often as desired, an important advantage in checking the success of the removal of fragments and in reviewing the situation after transpedicular cancellous bone grafting.

Adult↗

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↗

PubMed1992

[Experimental trial of intraoperative spinal ultrasound].

Dorsal operative stabilization of spinal fractures by internal fixation is an established means of treatment directed at releasing the extrinsic compression of the intraspinal contents caused by the fractured posterior surface of the vertebral body. There are few ways of assessing how successful the repositioning is intraoperatively. Intraoperative ultrasound with a special small transducer is possible, but it is difficult to reach the intraspinal area by this means, because it is surrounded by bones. A laminectomy would destabilize the injured vertebral column even further. By experiments performed on six human vertebral columns we show that it is possible to view the entire length of the fractured posterior surface by ultrasound. The beam has to be projected between the laminae vertebrae following a small laminotomy. Preliminary intraoperative experiences with eight patients confirm our experimental results. The intraoperative ultrasound results have been confirmed by preoperative and postoperative CT. We expect the necessity for laminectomy for examination of the posterior surface of the vertebral body to decline in frequency in the near future.

Child↗

PubMed1992

[The disease factor of scapholunate dissociation].

Scapholunate dissociation is the most common form of instability of the wrist. Its occurrence has been consistently attributed to previous trauma and is supposed to be treated by operation. In the present paper we show that chronic bilateral scapholunate dissociation without any symptoms is not rare. In two years we accidently found four cases with bilateral scapholunate dissociation. In such cases an operation cannot be successful. Therefore, we recommend that a specific trauma should be checked very carefully and roentgenograms of both wrists done.

Carpal Bones↗

PubMed1991

[Interpretation of MR tomography findings in trauma surgery].

MR-Imaging is well established as the most sensitive method for the diagnosis of avascular necrosis of the femoral head. In this paper preliminary results are analyzed in an attempt to clarify whether as in a vascular necrosis of the femoral head. MR changes after trauma or surgery allow conclusions concerning the vitality of the bone. Comparison of clinical, MR and histological findings revealed that we cannot yet differentiate between fibrosis of the bone marrow with sustained vitality of the osteocytes and bone necrosis. Therefore, conclusions with implications for therapy should be drawn with extreme care.

Adult↗

PubMed1990

[Treatment and results following rupture of the quadriceps tendon].

Ruptures of the quadriceps tendon are rather uncommon and are usually due to minor trauma. From 1971 to 1986 we observed 13 spontaneous ruptures in contrast to a single case due to adequate trauma. The average age of the patients was 64.0 years. There is no alternative to surgical reconstruction of the ruptured or torn out quadriceps tendon. Tendon-repair with supportive wire-looping produces a good functional result. After immobilisation of the knee for five to six weeks intensive physiotherapy is required. 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↗