Biomedical subjects
V Ewerbeck
Publications and source records attributed to V Ewerbeck.
Periprosthetic mineralization around cementless total hip endoprosthesis: longitudinal study and cross-sectional study on titanium threaded acetabular cup and cementless Spotorno stem with DEXA.
In a prospective longitudinal study over 2 years and a separate cross-sectional study more than 5 years after operation, we analyzed periprosthetic bone mineral density (BMD) after cementless total hip arthroplasty (THA) (press-fit cementless Spotorno stem, Mecron threaded acetabular cup) by dual-energy X-ray absorptiometry (DEXA). BMD was analyzed in a longitudinal prospective study (n = 53 patients: 29 women, 24 men) and in a separate cross-sectional study (n = 23 patients: 13 women, 10 men) with good clinical outcome (Merle d' Aubigne score > 12). Regions of interest were defined according to Gruen (ROI 1-7) and as netto average ROI (NETAVG I) for the periprosthetic femur, and according to De Lee and Charnley (ROI I-III) and as NETAVG II for the periprosthetic acetabulum. BMD during follow-up was compared with immediate postoperative values of the affected limb. Mean precision error (CV%) was 2.6 +/- 0.5% for ROI 1-7 and 1.3 +/- 0.9% for ROI I-III. BMD significantly decreased in the periprosthetic femur and acetabulum during the first 3 months after operation. At the femur, BMD (NETAVG I) for women and men, respectively, was 92.4% and 87.5% at 6 months, then 89.4% and 96.2% at 2 years. ROIs around the proximal stem showed the lowest absolute values and decreased most during follow-up (to 79.9% ROI 1 and 68.2% ROI 7, respectively). Mineralization around the cup (NETAVG II), respectively, amounted to 81.1%, 82.6% at 6 months, then 80.1% and 93.8% at 2 years. The medially placed ROI II demineralized most (respectively, 72.1% and 76.7%). More than 5 years after THA, BMD in the femur showed little change, but decreased significantly to 76.4% and 79.1%, respectively, around the cup (NETAVG II). DEXA is a useful method for analyzing changes of mineralization around cup and stem of cementless THA. The results reflect the different stress on the periprosthetic bone after implantation of THA in defined ROIs, supporting earlier reported good clinical results of the Spotorno stem and increased loosening rate of threaded acetabular cups after 5 years.
Modulation of resistance to anti-APO-1-induced apoptosis in osteosarcoma cells by cytokines.
The CD95/APO-1 Fas receptor/ligand system plays a crucial role in growth control by mediating apoptosis in lymphoid and non-lymphoid cells. To investigate the role of CD95-mediated apoptosis in osteosarcoma, we studied 3 human osteosarcoma cell lines (HOS/TE 85, MG 63 and Saos-2) and osteoblasts derived from bone biopsies. In contrast to osteoblast-like cells, all cell lines were resistant to anti-APO-1-induced apoptosis despite constitutive CD95 expression at intermediate levels. Blocking of macromolecular synthesis by cycloheximide or actinomycin D or modulation of CD95 expression by cytokines (TNF-alpha and/or gamma-interferon) restored sensitivity to anti-APO-1-induced cell death. PCR analysis of the CD95 transcripts revealed the production of a truncated splice variant that codes for a soluble form of the CD95 receptor. Synthesis and secretion of soluble CD95 protein into the culture supernatant was demonstrated by Western blot analysis. Treatment with sensitizing cytokines led to up-regulation of full-length CD95 transcripts and the encoded membrane-bound CD95 protein but not the truncated mRNA splice variant and the corresponding soluble receptor, as shown by PCR and Western blot analysis. The biological activity of soluble CD95 secreted by osteosarcoma cells was demonstrated by the ability of osteosarcoma supernatants to protect the sensitive T-cell line Jurkat from anti-APO-1-mediated apoptosis. Our results suggest that the production of soluble CD95 by osteosarcoma cell lines that may block physiological death signals and the production of membrane-bound CD95 are differently regulated by cytokines via modulation of RNA splicing.
[Ultrasound criteria for staging and follow-up of malignant lymphoma].
Ultrasonography is an integral part of the radiological imaging of malignant lymphomas for staging, therapy planning, monitoring, follow-up, post-therapeutic care, and detection of recurrences, as well as the diagnostic differentiation of benign lesions and metastasis of solid tumors. None of the imaging methods, including sonography, however, can safely determine the stage (UICC certainty level C4) in agreement with the pathohistological examination. Also considering the clinical appearance the sonographic criteria in the synoptic evaluation will nevertheless provide important indications for diagnosis and therapy planning. Not only changes in size and shape, but also the echogenicity (gray-scale histogram) and vascularization (color Doppler) of nodal and extranodal processes are decisive criteria for estimating the therapeutic response rates and detecting relapses.
IORT for extremity sarcomas.
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[Intraoperative radiotherapy in advanced soft tissue sarcoma of the extremities].
Radical or wide excision is the treatment of choice for soft-tissue sarcomas (STS) of the extremities. Multimodality therapy made limb-sparing surgery possible. While external beam radiotherapy is well established in this setting, few data are available about intraoperative radiotherapy (IORT). We performed an analysis of 36 patients treated with IORT and external beam radiation following resection of STS of the extremities between 1991 and 1995. Only STS classified as UICC stage IIb, III or IV were included. Operative morbidity was 17%, 14% showed late complications. Within a mean follow-up of 24 months (min. 6), there was one local recurrence in 30 patients treated curatively. The 3-year survival rate of patients treated curatively was 75%; 3-year recurrence-free survival was 65%.
Extraskeletal osteosarcoma with a highly malignant course. A case report.
A case of a highly malignant extraskeletal osteosarcoma is reported. Although biopsy is not considered necessary in cases of heterotopic calcification when the aetiology is known, malignancy should be suspected when the cause is questionable.
[Differential diagnosis of benign bone tumors. Clinical aspects and imaging procedures].
In the assessment of bone tumors and tumor-like lesions the first aim is to clarify potential malignancy and aggressiveness. To rely exclusively on clinical assessment is not sufficient. Imaging techniques are invaluable, the most important still being plain roentgenograms. Radiological assessment according to the Lodwick grading system is useful. MRI has now been established to be superior to further investigations. Ultrasonography has proved to be helpful as a noninvasive and cost-saving screening method, particularly in the presence of non pathologic X-ray findings and persistent complaints. Only non-ossifying fibroma and osteochondroma can be diagnosed reliably with X-ray. For solitary bone cysts, chondromas of small tubular bones and fibrous dysplasia, X-ray diagnosis can be doubtful. Most of the lesions to be considered have to be verified histologically. Specialized experience is necessary for the best selection and timing of diagnostic measurements in individual cases in order to prevent fatal errors.
[Benign bone tumors in the growth years--osteoid osteoma and osteoblastoma].
Osteoid osteoma (ICD: 9191/0) and osteoblastoma (ICD: 9200/0) are closely related entities of osteoblastic-type tumors. Osteoid osteoma is a small benign (lesion 1-2 cm or less) neoplasm that is richly vascularized. Nerve fibers within the tissue surrounding the nidus lead to the characteristic pain. A typical finding is the perifocal osseous reaction around the nidus. Osteoblastoma is a progressively growing lesion of a diameter larger than 2 cm; it is sometimes painful and is characterized by the absence of any reactive perifocal bone formation. For both tumors the treatment is complete surgical excision. If the nidus of the osteoid osteoma is removed, the patient will be free of pain. For the osteoblastoma the treatment depends on the stage and localization of the tumor. Forty-seven patients with osteoid osteoma and 10 patients with osteoblastoma have been treated in Heidelberg since 1980. The radiological investigations and surgical treatment are discussed.
[Arterial embolization as a therapeutic possibility of tumors of the skeletal system].
Arterial embolization is an approved method in treating bleeding tumors of the urogenital tract. In orthopedic patients it has been applied for hypervascularized skeletal metastases of the pelvic, spine and long bones. Intraoperative blood loss with its known risks can be markedly reduced. Reduction of pain has also been reported. The good results in our series of 9 patients together with the low incidence of side effects suggest that arterial embolization is indicated on a large scale.
[Characteristics of chondromyxoid fibroma: are malignant courses possible? Presentation of personal cases and review of the literature].
The chondromyxoid fibroma as a benign bone tumour is described. The difficult but extremely important differential diagnosis from chondrosarcoma is discussed, and the question of the existence of malignant chondromyxoid fibroma is examined. Cases of malignant chondromyxoid fibroma that have been reported in the literature are described and critically analysed. Experience with seven chondromyxoid fibromas and two tumours misdiagnosed as malignant chondromyxoid fibromas are described. In view of the clear definition of chondromyxoid fibroma and chondrosarcoma the term malignant chondromyxoid fibroma is not justified and should no longer be used.
[Clinical and roentgenologic changes after fibula resections: causes, differential diagnostic aspects, consequences].
This study correlates the clinical and radiological development of twelve patients with resection of the fibula, with the results of experimental investigations, reporting on the loss of tension-banding and proportional weight-bearing after fibula resection. Five patients underwent segmental fibula resection because of tumour disease, seven patients by reason of harvesting an intercalary allograft. Five patients suffered from lower leg pain. Spindle-shaped thickenings of the tibial cortex could be confirmed by most x-rays, in one case the tibial shaft diameter increased up to 10%. Usually the rest of the fibula will become atrophic in grown-up patients; in children the fibula may restore completely if the preparation is performed by sparing the periosteum. Three patients suffered a stress fracture of the tibia. As pain and tibial stress fracture appeared mainly if the remaining fibula was less than 1/4th of the original fibula length, the distal part should be preserved longer if justifiable from an oncological point of view. The knowledge about basic biomechanical behaviour and the arising possibility of a stress fracture or other structural changing of the tibia after fibula resection is important for correct assessment of the postoperative clinical and radiological development.
[Methodology, technical prerequisites and postoperative morbidity of intraoperative radiotherapy (IORT) of soft tissue sarcomas. Heidelberg Krankengut 6/91-9/92].
Since June 1991 the IORT facility has operated a dedicated linear accelerator, which was installed within the central operating theater of the Department of Surgery. As of 9/92 a total of 28 patients suffering from peripheral (n = 20) or centrally (n = 8) located soft tissue sarcomas had been were treated. Thirteen patients revealed a primary and 15 patients a recurrent tumor. Tumor resection with negative margins was performed in 20 patients, positive margins remained in 5 patients, and gross macroscopic residual disease in 3 patients. Combined intraoperative and external beam radiotherapy was applied in 22 patients, using IORT doses of 10-20 Gy and an external beam dose of 26-50 Gy. Three patients were irradiated intraoperatively twice with a time interval of 24 h. After a median follow-up of 9.9 months, 20 patients are disease free. Two patients died 4 and 5 months after the end of therapy with rapidly progressive distant metastases. An infield failure within the external beam target volume was seen in 1 patient and local failure at the field margin of the external field in 3 patients. So far, there have been no IORT infield failures. Follow-up is performed with magnetic resonance imaging. In 3 patients a second operation was necessary because of a severe wound infection, including one patient suffering from osteomyelitis of a neighboring bone. Mild sensory neuropathy occurred in 1 patient 7 months after treatment. Overall only mild and reversible postoperative and posttherapeutic complications were seen.(ABSTRACT TRUNCATED AT 250 WORDS)
[Sonography in therapy-oriented diagnosis and after-care of primary bone and soft tissue tumors].
Based on the results of 150 patients with primary tumors or the suspicion of malignant lesions of the locomotor system the perspectives and limits of the sonographic diagnosis under the therapeutic aspects of interdisciplinary oncologic cooperation is demonstrated. As the ideal adjunct to conventional roentgenograms, ultrasound is the first-line imaging procedure in the fields of primary diagnosis, follow-up, post-therapeutic care as well as tumor exclusion for methodic, patient-related and economic/logistic reasons. Its consequent application will markedly reduce the number of more invasive and expensive methods.
[Metastasizing malignant meningioma: a case report].
A case of metastasizing malignant meningioma is discussed concerning the etiology, clinical symptoms, diagnosis and therapy. The necessity of irradiation after surgery is turned out. Palliative treatment of bone metastasis is presented from an orthopedic point of view.
[Basic principles of amputation surgery. Surgical strategy, postoperative treatment and provision of prostheses].
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[Effect of a rasp surface on cement penetration in paired cadaver femurs].
AIM: The purpose of this investigation was to study two different broach surface designs with regard to cement penetration into human cancellous bone. METHODS: In a cadaver study 15 paired human cadaver femora were prepared using broaches of identical geometry but different surface characteristics. All left femora were prepared using chipped toothed broaches, all right femora using diamond shaped broaches. Cancellous bone was irrigated with 1 liter pulsed lavage. The specimens were imbedded in specially designed pots. Bone cement was applied in a retrograde manner and subjected to a standard pressure protocol with a constant force of 3000 N. Radiographs were taken and horizontal sections were obtained at predefined levels using a diamond saw. Microradiographs were taken and analyzed using image analysis to assess cement penetration into cancellous bone. RESULTS: Pressure curves recorded during cement pressurisation were comparable. The microradiographic evaluation revealed no significant morphometric differences in the different groups with regard to cement penetration into cancellous bone. These findings were similar in all sections obtained. CONCLUSIONS: A standardized model was developed allowing comparison of cement penetration into cancellous bone depending on bone preparation. In the presence of pulsed lavage there is no significant influence of broach surface characteristics on cement penetration into cancellous bone of the upper end of the femur.
[Significance of jet lavage for in vitro and in vivo cement penetration].
AIM: The purpose of this study was to determine the efficacy of pulsatile jet lavage and manual syringe lavage with regard to their cleansing capabilities as measured by cement penetration into cancellous bone both in vivo and in vitro. METHODS: Three separate experiments were performed. Study A: In a cadaver study 36 left human cadaver femora were used for implantation of cemented femoral components. Conventional broaches were used for femoral preparation. Bone lavage was carried out either using jet lavage or manual syringe lavage of equal volume. The allocation to two different lavage groups was randomised. In both groups high-pressurising cementing techniques were implemented with the use of a proximal seal and additional finger packing. Study B: To guarantee standardised cement pressurisation and equal bone quality, the influence of jet lavage (1000 ml) versus syringe lavage (1000 ml) was studied in 11 paired human cadaver femora in an additional study without prosthesis implantation. The specimens were imbedded in specially designed pots. Bone cement was applied in a retrograde manner and subjected to a standard pressure protocol with a constant force of 3000 N. Study C: To directly compare the effectiveness of both pulsatile jet and syringe lavage with regard to cement penetration in vivo, a new sheep model allowing for standardised bilateral, simultaneous cement pressurisation was used. After femoral neck osteotomies both femoral cavities of 10 sheep were prepared for retrograde cement application. After randomisation one side was lavaged with 250 ml irrigation using a bladder syringe, the contralateral femur with the identical volume but using a pulsatile lavage. A specially designed apparatus was used to allow for bilateral simultaneous cement pressurisation. ANALYSIS: In all studies horizontal sections were obtained from the femoral specimens at predefined levels using a diamond saw. Microradiographs were taken and analysed using image analysis to assess cement penetration into cancellous bone. RESULTS: Study A: Compared with syringe lavage the use of jet lavage significantly improved the penetration of cement into cancellous bone (p = 0.027). In the presence of strong, dense cancellous bone the findings were more pronounced. Study B: Our results show that in equal quality bone, the use of jet lavage yields significantly (p < 0.001) improved cement penetration compared to syringe lavage specimens. Study C: The results of the in vivo study confirmed the superiority of jet lavage bone surface preparation (p = 0.002). CONCLUSIONS: The use of jet lavage yields significantly improved interdigitation between cancellous bone and cement both in vitro and in vivo and should be regarded as mandatory in cemented total hip arthroplasty. High pressurising techniques are effective means to improve cement penetration, but should only be administered with jet lavage to reduce the risk of fat embolism.