Biomedical subjects

K Wenda

Publications and source records attributed to K Wenda.

At least 19 recordsLinked to original sources

PubMed2005

[Angiographic embolization of seriously bleeding vessels as an emergency procedure after traumatic disruption of the symphysis].

Bleeding after instable fractures of the pelvic ring results in a mortality-rate of 7-21 percent. A 65-year-old male patient who fell from his horse and sustained an open book injury with disruption of the symphysis and iliosacral joint developed a dangerous haemorrhagic shock situation in the emergency room. A computer tomography with contrast medium was performed immediately. The outflow of contrast medium behind the symphysis indicated an acute arterial bleeding. An angiography revealed a bleeding from both Aa. obturatoriae and the right A. epigastrica inferior. The difficulty to stop the bleeding surgically resulted in the decision to embolize the vessels angiographically. This procedure terminated the acute bleeding and haemorrhagic shock situation immediately. The pelvic ring disruption was stabilized by internal fixation ten days later. The patient had an uncomplicated course.

Aged↗

PubMed2005

[New osteosynthesis techniques for the treatment of distal femoral fractures].

The treatment of distal femoral fractures was for a long-time associated with high complication rates. Although implants and surgical techniques were improved, plate osteosynthesis and intramedullary nailing suffered from considerable rates of infection, non-union und malalignment. Attention to the soft tissue envelope by "biological" osteosynthesis and minimally invasive approaches resulted in decreased complication rates. Out of this movement grew the concept of minimal invasive plating with an internal fixator -- the LISS-DF (Less Invasive Stabilization System -- Distal Femur) -- and the retrograde nailing concept. This article should give a review about these two new techniques for the treatment of distal femoral fractures. Indications, the clinical use and the aftercare will be discussed.

Bone Plates↗

PubMed2003

[Total hip arthroplasty for metastatic Merkel cell carcinoma].

Merkel cell carcinoma is an extremely rare malignant tumor which derives from the neuroendocrine cell system with features of epithelial differentiation. It belongs to the APUD-system (amine and precursor uptake and decarboxylation) and is characterized by highly aggressive spread with a predisposition for local recurrence and local regional and distant metastases. Metastatic spread to the hip has not been described in the literature before. We report on a 76-year old male patient with metastases of the left femoral head and greater trochanter 3 1/2 years after excision of a Merkel cell carcinoma of the left thigh with consecutive radical lymph node dissection of the left inguinal area and radiation therapy. Although microscopic,immunohistological and ultrastructural characteristics of the carcinoma have been well defined, there are no established treatment guidelines and prognostic factors that may predict the behaviour of the tumor due to the limited number of cases. Elective lymph node dissection decreases the rate of local recurrence but is not associated with improved overall survival. At the time of establishing the diagnosis, about half of the patients has positive lymph nodes with a 3-year-survival rate of 60%.

Aged↗

PubMed2002

[Vertebral body stenting. A method for repositioning and augmenting vertebral compression fractures].

UNLABELLED: Purpose of the study was to demonstrate the effectiveness of expanding a fractured vertebral body by transpedicular dilatation and stenting. 7 human cadaveric vertebral bodies from L2 to L5 underwent axia compression until a vertebral burst fracture was provoked. Then, by bilateral transpedicular approach, balloon-catheters were introduced, which were armed with stents, usually used for angioplasty. The catheters were inflated with radiolucent fluid and the stents expanded under radiologic control. After expansion, the balloon was deflated and removed, the stents resting inside the vertebral body, holding their inflated shape. Then, the resulting hole was filled with an injectable biodegradable calcium-phosphate. CT-scans were performed after destruction and after expansion. Morphology before and after expansion was judged, using 3-D reconstructions. Vertebral body strength was measured before destruction and after treatment with an Instron testing machine. RESULTS: Vertebral body shape could be restored. Also impressed central parts of the bony endplate could be elevated by using a convergent approach through the pedicles. There was no collapse of the vertebral body after removing the catheter-balloons The vertebral body strength could be restored up to a physiologic level. This procedure gives new perspectives in the treatment either of osteoporotic compression or traumatic vertebral fracture. By using CT-guided technique, it could be performed by a minimally invasive approach percutaneously.

Aged↗

PubMed2002

[In situ connection of a hollow intramedullary nail to the stem of a knee prosthesis in periprosthetic fracture].

Periprosthetic fractures often reveal problems and complications because of poor bone quality. A case report is presented, in which a hollow intramedullary nail was connected, in situ, with the stem of a knee prosthesis (Blauth knee). Two plate osteosyntheses had previously failed. As ultima ratio, a hollow intramedullary nail was placed antegrade on the stem of the knee prosthesis. Afterwards excellent callus formation developed and resulted in consolidation.

Aged↗

PubMed2001

Traumatic intervertebral disc lesion--magnetic resonance imaging as a criterion for or against intervertebral fusion.

Lesions of the intervertebral disc accompanying vertebral fractures are the subject of controversy and discussion regarding the extent and manner of surgical intervention. The question of when to perform disc resection and intervertebral fusion, in particular, has not been answered satisfactorily. In order to evaluate short- and medium-term lesions of the discoligamentous complex associated with thoracolumbar burst fractures, magnetic resonance images made after stabilisation and again after implant removal were compared. Between 1997 and 1998, 20 patients who had suffered thoracolumbar burst fractures (AO classification A3 and B1 [26]) underwent posterior reduction and stabilisation using a Universal Spine System (USS, Synthes, Switzerland) titanium internal fixator. The implant was removed after an average of 10 months. Magnetic resonance imaging (MRI) scans were performed 1 week after both operations, allowing the changes in a total of 40 intervertebral discs adjacent to the fractured vertebral body to be investigated. The analysis was based on signal intensity of the intervertebral disc in T2-weighted scans and on morphological criteria. A total of 81% of the discs with initially normal T2-weighted signal showed the same signal after implant removal; 5 discs with initially increased signal intensity in T2-weighted scans normalised, 5 showed a decrease in intensity and 3 suffered a partial loss of signal. Among the 9 discs with initially decreased T2-weighted signal, only one had normalised by the time the implant was removed. A total of 86% of the 14 morphologically intact discs retained their structural integrity. Of the 25 discs with minor defects, only one could be considered as intact after implant removal, 15 remained the same and 9 deteriorated in structure. No disruption of the fibrous ring or of the posterior longitudinal ligament was observed, nor was there any prolapse of intervertebral discs. When the intervertebral disk is intact and has normal morphology and a normal T2-weighted MRI signal, resection or fusion of the fracture adjacent discs appears unjustified. In our opinion, the results do not support the possibility of predicting degradation in those discs that showed an altered T2-weighted signal after the first operation.

Adolescent↗

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↗

PubMed1997

Minimally invasive plate fixation in femoral shaft fractures.

Bridge-plating with its advantages in terms of vascularity and bone healing is a well established procedure today in the treatment of comminuted femoral fractures. Bridge-plating means that the fracture site is not interfered with during the operative procedure. This paper introduces a surgical technique in which the plate is inserted through isolated proximal and distal incisions only, behind the vastus lateralis. Alignment is secured by the plates, the fracture site remains untouched, fixation and screw insertion is restricted to the proximal and distal main fragments. Longitudinal femoral fractures extending right into the trochanteric and or condylar areas are the main indication for minimally invasive plate fixations with angled blade plates or condylar screws since fractures which are restricted to the diaphyseal area are mostly treated by nailing today. The surgical trauma resulting from plating by proximal and distal incisions only is less than that associated with conventional techniques. Indirect reduction of femoral fragments is much easier since the integrity of the surrounding muscles and soft tissue is preserved, the fragments often being reduced simply by traction. Adjustment of rotation is an essential aspect requiring careful attention. For special indications, namely comminuted fractures affecting a large part of the femur and extending into the trochanteric or condylar areas, insertion of the plate via proximal and distal incisions only is a further development in bridge-plating which minimizes surgical trauma and operation time.

Bone Plates↗

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↗