Biomedical subjects

K Wenda

Publications and source records attributed to K Wenda.

At least 19 recordsLinked to original sources

PubMed1998

Ultrasound-guided spinal fracture repositioning.

The management of narrowing spinal fragments in the operative treatment of spinal fractures remains an open question, in particular when the procedure is performed by a posterior approach. This article describes the use of intraoperative ultrasonography during spinal surgery. From 1990 to 1997, 116 spinal fractures were treated operatively at our clinic. Stabilization of the spine was achieved with the AO fixateur interne and the AO USS, respectively (Synthes, D-79224, Umkirch, Germany). For 60 cases who had a fractured posterior vertebral surface dislocated into the spinal canal, we used intraoperative ultrasonography to monitor the repositioning of the narrowing fragments. The patients underwent pre- and postoperative computed tomography scans (CT). In six cases, color-coded duplex sonography was performed intraoperatively to view the A. spinalis anterior. In 58 cases, the spinal canal and the fractured posterior surface of the vertebrae were visualized successfully. The sonographic image was inconclusive in two cases with severely damaged fragments. Identical findings were observed on the intraoperative ultrasound image after completion of repositioning and on the postoperative CT scan. In six cases, the A. spinalis anterior was viewed by color-coded duplex sonography with a different flow before and after fracture repositioning. Intraoperative ultrasound is a valuable means of monitoring the restoration of the spinal canal by a posterior approach. The method is easy to perform and can be repeated as often as required. Color-coded duplex sonography allows further visualization of the A. spinalis anterior.

Fracture Fixation, Internal↗

PubMed1998

Radiation exposure to the hands and the thyroid of the surgeon during intramedullary nailing.

During 41 procedures of intramedullary nailing of femoral and tibial fractures, the primary surgeon and the first assistant wore ring dosimeters on their dominant index fingers. While the average fluoroscopy time per procedure was 4.6 min, the average dose of radiation to the dominant hand of the primary surgeon was 1.27 mSv and 1.19 mSv to the first assistant. The dose limit for the extremities is 500 mSv per year, as recommended by the International Commission on Radiological Protection. Extrapolation of the mean dose of the primary surgeon and first assistant per procedure of 1.23 mSv leads to the result that the recommended dose limit of 500 mSv would only be exceeded if more than 407 intramedullary nailing procedures are carried out per year. The duration of fluoroscopy time correlated with the radiation dose to the hands of the surgeons, though it was determined by phantom measurements that the majority of radiation exposure occurred during brief exposures of the hands in the direct X-ray beam on the X-ray tube near side of the patient. In order to assess the surface doses of the thyroid gland to the primary surgeon with and without a lead shield, we performed in vitro measurements during operative procedures of the lower leg simulating different intraoperative situations under fluoroscopic control. The average registered ionizing dosage without a thyroid shield was approximately 70 times higher than with thyroid lead protection. In a previous study we found average fluoroscopy times during intramedullary nailing of the tibia and femur of 4.6 min per procedure. Extrapolation of this value leads to the result, that even when 1000 intramedullary nailings were carried out without wearing lead protection, only 13 per cent of the dose limit recommended by the International Commission on Radiological Protection for the thyroid of 300 mSv per year would be reached; by wearing the lead protection only 0.2 per cent of the recommended dose would be reached.

Femoral Fractures↗

PubMed1997

[Paradoxical embolism after femoral fracture].

The foramen ovale is anatomically open in 25% of individuals, but functionally closed by the higher pressure in the left antrum. Right-to-left shunt and subsequent paradoxical embolism may occur when pressure in the left antrum rises, for example, as a result of pulmonary embolism. In the present case we demonstrate a patient who presented 20 days after osteosynthetic treatment of a femoral fracture with word-finding deficits. Cerebral MRT revealed a fresh ischemic insult. Duplex ultrasound of the legs showed a fresh thrombosis of the superficial femoral vein and scintigraphy of the lungs detected pulmonary embolism. Transesophageal contrast echocardiography trapped a hemodynamically spontaneous, open foramen ovale. Duplex ultrasound of the carotid arteries detected no pathological findings. Deep vein thrombosis and pulmonary embolism can be clinically inconspicuous and become manifest by cerebral deficits resulting from paradox embolism and cerebral ischemia.

Aged↗

PubMed1996

[Long-term outcome of managing medial femoral neck fractures with ceramic head endoprostheses].

Total hip replacement is often recommended for the treatment of femoral neck fractures in elderly patients. A less invasive approach with shorter operating time is the replacement of the femoral head only, leaving the acetabular cartilage in situ. Hemiarthroplastic hip replacement using a metallic head prosthesis was not successful in the past, because the majority of patients developed protrusio acetabuli after surgery. In the present study hemiarthroplastic hip replacement using an Al2O3-ceramic head was shown to be a useful method for the treatment of femoral neck fractures in elderly patients. From 1985 to 1990 277 patients were treated with hemiarthroplasty. The average age at the time of accident and operation was 81.7 years. At the time of follow-up in 1993 only 77 survivors were available for examination. A standardized score was calculated assessing activity, gait, hip pain, etc., with the patients obtaining an average score of 58 out of possible 78 points. Only three patients had hip pain, and in four cases the roentgenographic examination revealed protrusio acetabuli. Two of these four patients underwent revision surgery for replacement of the cup, leaving the stem in situ. In view of the small number of approach-related complications, hemiarthroplastic hip replacement using an Al2O3-ceramic head is the recommended surgical treatment for femoral neck fractures in elderly patients. In the rare patient with protrusio acetabuli, revision surgery can be performed to replace the cup, leaving the stem in situ.

Activities of Daily Living↗

PubMed1996

[Results of primary unreamed tibial nailing of tibial fractures with severe open or closed soft tissue injuries].

Primary stabilization was performed in 72 tibial fractures with sever open (n = 37) or closed (n = 35) soft tissue injury using unreamed interlocking nails. In 60 (83%) cases the fractures healed without additional procedures. There were 2 cases of osteitis, but both these fractures healed after removal of the nail or after reamed nailing. In 9 patients with delayed union reamed nailing (n = 8) or bone grafting (n = 1) led to healing. In 1 patient with hypertrophic pseudarthrosis, union was achieved after substitution of a reamed nail for the anreamed nail. The infection rate was similar to that observed with external fixation. More secondary procedures, such as bone grafting or a change of the osteosynthesis technique, are necessary with external fixation than with unreamed nailing. Further advantages of unreamed nailing are the internal treatment of the fracture and the patient's greater comfort. Therefore, unreamed nailing can be recommended for the primary treatment of tibial fractures with severe open or closed soft tissue trauma.

Adolescent↗

PubMed1996

[Systemic complications in intramedullary nailing].

Today intramedullary nailing is the treatment of choice in stabilizing femoral and tibial diaphysial fractures because of its superior bone healing compared to other forms of osteosyntheses. By interlocking, the indication can be extended to all fractures in which interlocking bolts can be fixed in the proximal and distal main fragment. Küntscher's principle of elastic clamp has changed to intramedullary splinting. With that method reaming is limited to a few reaming processes, and unreamed nailing has become possible. Today implants start at a diameter of 9 mm. The diameter of implants of all manufacturers is less than a few years ago. Since the importance of embolization by increasing the intramedullary pressure as a result of reaming is accepted, the question arises concerning the clinical relevance of embolization if reaming is restricted and unreamed nails are applied. In our own investigations, relevant intravasation of bone marrow content appeared only in reamed femoral nailing. The bone marrow cavity of the tibia is smaller, the configuration of the tibia allows more back-streaming of the content, and the venous drainage system in the distal tibia is much less extensive than in the supracondylar area. All pulmonary complications in the literature are reported after nailing of femoral fractures. Therefore, systemic complications in intramedullary nailing are only a problem in femoral fractures. The pathophysiological connection between intramedullary pressure increases and pulmonary impairment is not clarified in detail. Relevant content of the bone marrow cavity is not only bone marrow, but also the blood with which the marrow cavity is refilled after each reaming process and which passes into the circulation during the following reaming. This blood is activated concerning coagulation. By reaming, the pathogenic content of the bone marrow cavity is embolized, which can become clinically relevant if cofactors are present. Cofactors are volume deficit, shock, lung contusion and pre-existing pulmonary impairment. These conditions can never be excluded before primary stabilization after trauma. Today the importance of systemic complications during unreamed nailing is controversial. Our experimental and echocardiographic investigations clearly show that the velocity of the nail into the bone marrow cavity and the gap between the nail and cortical bone at the entrance in the distal fragment determine the amount of embolized material. By carefully inserting the nail and choosing thin nails with a correct length, which can gain stability by fixation in the condylar area and not by clamping in the distal fragment, echocardiography reveals only minimal embolization. Therefore unreamed nailing is the treatment of choice, if the situation of the patient allows the procedure of nailing in itself. Multitrauma patients in shock or with unstable circulation should be stabilized primarily with external fixation. After consolidation, early change to an intramedullary nail should be performed.

Embolism, Fat↗

PubMed1996

[Radiation burden to the hands of surgeons in intramedullary nailing].

During 41 procedures of intramedullary nailing of femoral and tibial fractures the primary surgeon and the first assistant wore ring dosimeters on their dominant index fingers. While the average fluoroscopy time per procedure was 4.6 min the average dose of radiation to the dominant hand of the primary surgeon was 1.27 mSv and 1.19 mSv to the first assistant. The dose limit for the extremities is 500 mSv per year recommended by the International Commission on Radiological Protection. Extrapolation of the average dose of the primary surgeon and first assistant per procedure of 1.23 mSv leads to the result, that the recommended dose limit of 500 mSv would only be exceeded if more than 407 intramedullary nailing procedures are carried out per year. The duration of fluoroscopy-time correlated with the radiation dose of the hands of the surgeons, though it was determined by phantom measurements that the majority of radiation exposure occurred during brief exposures of the hands in the direct X-ray beam on the X-ray tube near side of the patient.

Body Burden↗

PubMed1995

[The "inserted" condylar plate].

Twelve extensive segmental and comminuted fractures of the femur affecting the metaphyseal areas (7 times proximal, 5 times distal) and the diaphysis were treated with extremely long condylar plates (16 to 20 holes). The condylar plates were inserted via a proximal and a distal incision leaving the Musculus vastus lateralis intact at the fracture site in all cases. Following standard preparation of the blade position using the seating chisel, the condylar plate was inserted behind the musculus vastus lateralis with the blade pointing towards the surgeon. The condyles or the trochanteric area were tilted slightly and the plate was turned 180 degrees and driven home. No screws were inserted in the area of the fracture, in particular, lag screws were not used. Ten out of 12 fractures healed without problems, in 2 cases bone grafting was necessary. Three main observations resulted from analysis of the operations and subsequent clinical and radiographical assessments. In the presence of relatively intact soft tissue covering, an astonishingly good reduction of the fragments was achieved after restoration of leg length and extension. In the healing process, callus formed rapidly and provided medial support. The bone structure was found to be more homogeneous than in the case for plate fixation involving several screws at the fracture site around which considerable fluctuations in bone density frequently occur. The application of condylar plates behind the musculus vastus lateralis by only proximal and distal incision for osteosyntheses of extensive multifragmental fractures is a further development of bridge-plating and can be recommended for long fractures.

Bone Plates↗

PubMed1995

[Color-coded duplex ultrasound as a screening method in trauma surgery].

Deep vein thrombosis with consecutive pulmonary embolism is one of the most important complications for trauma patients. At the University Hospital of Mainz, Department of Traumatology, colour duplex ultrasound is used as screening method in trauma patients. Fractures of thoracic and lumbal spinal bones, pelvis, hip and lower extremities, endoprosthesis of hip and knee joints and longer immobilisation are considered as special risk for the genesis of deep vein thrombosis. Out of 326 patients investigated with colour duplex ultrasound, 24 patients suffered from unknown deep vein thrombosis, 8 developing pulmonary embolism. We recommend colour duplex sonography on day 10, after the third week, and after longer immobilisation. Colour duplex sonography provides an easy performable and noninvasive method for screening evaluation of deep vein thrombosis in trauma patients.

Adolescent↗

PubMed1995

[Isolated dislocation of the os triquetrum--a rare wrist injury].

The isolated traumatic dislocation of the triquetrum is an extremely rare injury. The clinical signs are unspecific. Roentgenograms of the wrist in posteroanterior and lateral views, possibly complemented by oblique views, will help to provide the diagnosis. The best therapy appears to be the open reduction and fixation with Kirschner wires. With the presented case report, the difficulties in using the classification carpal injuries are discussed. Finally, corresponding to the carpus ring theory, the plausibility of additional injuries to carpal ligaments in such trauma is pointed out.

Adult↗

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

[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↗