S Assenmacher

University Hospital Essen, Essen, North Rhine-Westphalia, Germany

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Publications (21)24.02 Total impact

  • Materialwissenschaft und Werkstofftechnik 12/2001; 32(12):942-948. · 0.51 Impact Factor
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    ABSTRACT: Die immunologische Gewebereaktion auf Osteosyntheseplatten aus Reintitan, eingesetzt zur Versorgung von Frakturen langer Röhrenknochen, wurde histologisch untersucht. Dazu wurde periimplantäres Gewebe im Rahmen der Metallentfernung bei 10 konsekutiven Patienten entnommen und mittels Immunhistochemie auf immunkompetente Zellen untersucht. 7 Patienten wiesen eine makroskopische, alle Patienten eine mikroskopisch nachweisbare Metallose auf. Die gefundenen Titanpartikel befanden sich zum größten Teil in CD68-positiven Makrophagen, die zum Teil MHC-Klasse-II-Moleküle exprimierten. Darüber hinaus fanden sich in Partikelnähe CD45RO-positive T-Lymphozyten, die teilweise Cluster bildeten und in wenigen Fällen auch CD8 + zytotoxische T-Lymphozyten. B-Lymphozyten ließen sich nicht nachweisen. Die Anwesenheit von Titanpartikeln wurde mit Hilfe einer REM-EDX-Analyse bestätigt.Immuno-inflammatory response to titanium particles – Histological investigations in the tissue adjacent to the limited contact-dynamic compression plate (LC-DCP)The immuno-inflammatory response to titanium plates used for the internal fixation of long bones was studied histologically. The soft tissue adjacent to the surface of titanium plates was examined by means of immunohistochemical methods in ten patients. The tissue was discoloured black as a sign of metallosis in 7 patients. Titanium particles located in macrophages (CD68 +) were observed in all patients. Some of them expressed MHC class II molecules. T-lymphocytes (CD45RO +) were detected in the vicinity of titanium particles. CD8 positive cells were also observed, whereas B-lymphocytes (CD79α +) were absent. The presence of titanium was confirmed by energy-dispersive X-ray analysis.
    Materialwissenschaft und Werkstofftechnik 02/2001; 32(2):172 - 177. · 0.51 Impact Factor
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    ABSTRACT: We compared the motion-stable wire suture by Towfigh (MSWST) with a modified Kessler suture (MKS) by following up flexor tendon repairs (MSWST, n = 21/39 digits; MKS, n = 20/31 digits). For MSWST we found 31 (79.5%) "excellent", 3 (7.7%) "good", and 5 (12.8%) "fair" results, when using the scoring system of Buck-Gramcko. In 3 (14.3%) patients the MSWST had to be removed owing to local irritation. In a further 3 (14.3%) patients, this was done when secondary tenolysis was necessary. The latter was also performed in 4 (20.0%) patients in whom the MKS was used. Here we found 23 (74.2%) excellent, 7 (22.6%) good, and 1 (3.2%) fair result. The statistical evaluation of the data concerning the patients' age, sex, the involved zone, the side, and the functional outcome did not reveal a significant difference (P < 0.05) between both groups and the chosen type of repair. The results of MSWST and MKS are similar, but MSWST allows early motion therapy without a splint or rubber-band protection.
    Archives of Orthopaedic and Trauma Surgery 02/2001; 121(4):212-8. · 1.36 Impact Factor
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    ABSTRACT: The aim of the present study was to investigate a systemic induction of bone formation in rats by immunosuppression with FK506 (1 mg/kg body weight intraperitoneally [ip]) in a model of osteoinduction of isogeneic and xenogeneic demineralized bone matrix (DBM) for a period of 28 days. In particular, alterations of in vitro cytokine synthesis and changes of lymphocyte subsets were studied. DBM was implanted intramuscularly in the abdominal wall of Lewis rats (seven per group). Blood was sampled on days -7, 0, 7, and 28 for determination of in vitro tumor necrosis factor a (TNF-alpha) synthesis and lymphocyte subsets by flow cytometry (CD3+, CD4+, CD8+, CD45+, ED9+, and Ia+ antibodies). Ossicles of de novo formed bone and the tibias were removed on day 28 after double tetracycline labeling for histomorphometric analysis. Immunosuppression with FK506 significantly decreased lipopolysaccharide (LPS)-stimulated in vitro cytokine synthesis after 7 days and 28 days (p < 0.05). Compared with control animals FK506 treatment significantly increased the volume of induced bone in isogeneic (2.1 +/- 0.3 mm3 vs. 10.8 +/- 0.9 mm3) and xenogeneic (O mm3 vs. 4.7 +/- 0.8 mm3) DBM. Bone histomorphometry of the tibias revealed that immunosuppression increased both bone formation and bone resorption, accompanied by a significant reduction in the relative trabecular area (Tb.Ar). FK506 caused a decrease in the counts of CD8+ T cells probably because of destruction or dislocation of these cells. This suggests that the amount of CD8+ cells and the degree of T cell activation in terms of mean fluorescence intensity (MFI) may be associated with bone metabolism. In support of this, statistical analysis revealed a significant positive correlation between parameters of bone formation as well as bone resorption and the CD4+/CD8+ ratio. There was a significant negative correlation between parameters of remodeling of the metaphysis of the tibia and induced bone volume (BV), respectively, and MFI values of CD3+/Ia+ cells. These findings suggest an important role of T lymphocytes in bone formation and bone resorption in vivo. FK506 caused a marked increase of bone formation in DBM. However, the conclusion that immunosuppression increases fracture healing warrants further investigation.
    Journal of Bone and Mineral Research 09/2000; 15(9):1825-34. · 6.13 Impact Factor
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    ABSTRACT: The aim of the following article is to summarize our experience in the treatment of osteiod osteomas, with special emphasis on diagnostic and therapeutic pitfalls. A consecutive series of 14 patients with osteoid osteomas was treated surgically between 1985 and 1996. All tumors but one were located in the lower limb. The main symptom was pain, being worse at night and being responsive to oral salicylates (10/14 patients). As reported in other studies, the duration of symptoms was unacceptably long (mean 24 months). The classical pathognomonic symptoms were misinterpreted in many cases, leading to frustrating conservative and even operative therapies. Open biopsy prior to surgical excision is not indicated because of the typical clinical and roentgenographic imaging of these lesions. Surgical excision of the nidus is the treatment of choice and gives immediate pain relief. If the characteristic morphology is not evident in plain roentgenograms, conventional tomograms, radionuclide scans and computerized tomography are reliable tools. All patients were free of disease at a mean of 6.6 years after operation. In symptomatic patients with osteoid osteomas the excision of the nidus is the established diagnostic/therapeutic modality. Minimally invasive procedures seem to be alternatives to classical surgery.
    Der Chirurg 04/2000; 71(3):319-25. · 0.52 Impact Factor
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    ABSTRACT: In the treatment of posttraumatic contracture of the elbow joint, arthrolysis is a proven procedure. We used a stepwise operative approach starting laterally and including an additional medial and dorsal incision if needed. A total of 91 patients with arthrolysis of the elbow could be followed-up on average 44 months (range 9-102 months) joint after operative (58, 63.7%) and non-operative (33, 36.3%) fracture treatment. The mean preoperative range of motion (ROM) in flexion/extension was 49 degrees (SD +/- 38 degrees), while in pronation/supination it was 89 degrees (SD +/- 66 degrees). Postoperatively, the ROM was on average 94 degrees (SD +/- 27 degrees) in flexion/extension and 129 degrees (SD +/- 52 degrees) in pronation/supination. Using our own grading system, it became evident that most patients had a functional benefit from the procedure, although the quality of the improvement differed. For example, postoperatively 59.3% of the patients were grade I (> or = 90 degrees) in flexion/extension compared with 16.5% preoperatively. Although the rest also showed improvements, their functional benefit was less. The earlier the release of the joints was performed, the better was the functional outcome (p < 0.05). The importance of an intensive early rehabilitation programme is emphasised while indications for this procedure should only be seen in compliant patients.
    Archives of Orthopaedic and Trauma Surgery 01/2000; 120(10):562-9. · 1.36 Impact Factor
  • Der Unfallchirurg 10/1999; 102(9):716-32. · 0.64 Impact Factor
  • Der Unfallchirurg 07/1999; 102(9):716-732. · 0.64 Impact Factor
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    ABSTRACT: To evaluate complications and the oncological and intermediate-term functional results in patients with bone and soft tissue tumors of the shoulder girdle who were managed with interscapulothoracic resection (Tikhoff-Linberg procedure). Case series of 19 consecutive patients during a 10-year period at a mean follow-up of 6.3 years (range, 1-11 years). University hospital; referral center for musculoskeletal tumor surgery. The initial diagnosis in this consecutive series of patients with shoulder girdle tumors requiring the Tikhoff-Linberg procedure was chondrosarcoma in 7 patients, Ewing sarcoma in 3 patients, malignant fibrous histiocytoma in 3 patients, solitary metastasis of thyroid carcinoma in 2 patients, osteosarcoma, synovial sarcoma, angiosarcoma, ancd neurofibrosarcoma in 1 patient each. According to the Musculoskeletal Tumor Society staging system, there were 6 in surgical stage IB, 10 in stage IIB, and 3 in stage III. Nine tumors involved the proximal humerus, 8 were located in the scapula or surrounding soft tissues, 1 in the lateral clavicle, and 1 in the acromioclavicular joint. For reconstruction of the proximal humerus after en bloc tumor resection an isoelastic cemented shoulder tumor prosthesis was inserted in every patient to restore arm length. Complications, and oncological and intermediate-term functional results. Twelve patients were alive with no evidence of disease. One of these patients died of nontumorous disease 2 years after surgery. One patient is alive with pulmonary metastases after 12 months. Six patients died of metastases at a mean (SD) interval of 18 months (range, 3-35 months) postoperatively. Two of these patients had additional local recurrence. A deep infection necessitated the explantation of the prosthesis in 1 patient. The mean functional score and SD according to the rating system of the Musculoskeletal Tumor Society was 72%+/-14% (range, 33%-87%) for the 12 surviving patients evaluated. Major complications (1 infection and 2 local recurrences) that may be attributed to the procedure occurred in 3 of the 19 patients. Despite an overall complication rate of 74% the Tikhoff-Linberg procedure proved to be a valuable surgical procedure for extended tumors of the shoulder girdle for functional and oncological outcome and is superior to forequarter amputation.
    Archives of Surgery 04/1999; 134(3):252-7. · 4.10 Impact Factor
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    ABSTRACT: Ninetten consecutive patients with bone and soft tissue tumors of the shoulder girdle were treated with interscapulothoracic resection (Tikhoff-Linberg procedure) over a 10-year period. Twelve patients were alive with no evidence of disease at a mean follow-up of 6.3 (1-11) years and one patient is alive with local recurrence and pulmonary metastases after 15 months. Six patients died due to pulmonary metastases. Despite these complications, the Tikhoff-Linberg procedure proved to be a valuable operation for extended tumors of the shoulder girdle in terms of functional and oncological outcome and is clearly superior to forequarter amputation.
    Langenbecks Archiv für Chirurgie. Supplement. Kongressband. Deutsche Gesellschaft für Chirurgie. Kongress 02/1998; 115:1414-6.
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    ABSTRACT: In 30 patients (12 male and 18 female) with extensive lesions of the cartilage of the upper and lower ankle joint, controlled partial-loading of the lower extremity was established by means of the load-relieving orthosis by Allgöwer and Wenzl. In these orthoses a hidden step-counter could be integrated. Average patient age was 46 (range 20 to 74) years. The load-relieving orthosis was used on average for 68 (range 22 to 98) days with a mean of 10,756 steps (range: 261 to 30,538); respectively 158 steps per day. Neither age, sex, diagnosis nor the duration of complete postoperative immobilisation correlated with the number-of-steps-per-diem compliance (r > +0.22).
    Unfallchirurgie 11/1997; 23(5):200-4.
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    ABSTRACT: Pulmonary gas exchange in correlation with condensed lung volume was prospectively studied in 10 patients with multiple injuries and blunt chest trauma. The purpose was to find nomograms that allow the estimation of the extent of pulmonary density from gas exchange parameters. The condensed lung volume was determined planimetrically from serial transverse sections of chest computed tomographic scans. There was no correlation between condensed lung volume and mean pulmonary artery pressure, pulmonary vascular resistance, systemic vascular resistance, or cardiac index and a week negative correlation to the oxygenation index (PaO2/FIO2) (r2 = 0.46) and to the total static lung compliance (r2 = 0.29). A strong correlation between pulmonary density and intrapulmonary shunt fraction (Qs/Qt) (r2 = 0.95) as well as alveoloarterial PO2 difference (P[A-a]O2) (r2 = 0.86) was evident. By using linear regression equations (linear regression line with 95% confidence interval), nomograms were calculated. The extent of pulmonary density can easily be obtained from these nomograms by measuring Qs/Qt or P(A-a)O2. The presented nomograms may be helpful in monitoring the effect of treatment in patients with blunt chest trauma.
    The Journal of trauma 08/1997; 43(1):8-12. · 2.35 Impact Factor
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    ABSTRACT: Bei 30 Patienten, die wegen eines erheblichen Knorpelschadens des oberen und/oder unteren Sprunggelenkes einseitig zur postoperativen Nachbehandlung mit einer dynamischen Teilbelastungsvorrichtung nach Allgöwer/Wenzl versorgt wurden, konnten verdeckte Schrittzähler in den Gehapparaten installiert werden. Das durchschnittliche Alter der Patienten betrug 46 (Spanne: 20 bis 74) Jahre. Die Teilbelastungsvorrichtungen wurden im Mittel 68 (Spanne: 33 bis 98) Tage genutzt. Dabei wurde eine mittlere Schrittzahl von 10756 (Spanne: 261 bis 30538) erreicht, das entspricht einer täglichen mittleren Nutzung von durchschnittlich 158 Schritten. Eine Vorhersage, welcher Patient seine Orthese nutzen wird, ist aufgrund des Alters, des Geschlechtes und der Diagnose der Patienten nicht möglich. Denn zu diesen Daten und auch zur Dauer der vollständigen postoperativen Entlastung ergab sich bei der statistischen Gegenüberstellung zur täglichen Schrittzahl keine Korrelation mit r > +0,22. In 30 patients (12 male and 18 female) with extensive lesions of the cartilage of the upper and lower ankle joint, controlled partial-loading of the lower extremity was established by means of the load-relieving orthosis by Allgöwer and Wenzl. In these orthoses a hidden step-counter could be integrated. Average patient age was 46 (range 20 to 74) years. The load-relieving orthosis was used on average for 68 (range 22 to 98) days with a mean of 10756 steps (range: 261 to 30538); respectively 158 steps per day. Neither age, sex, diagnosis nor the duration of complete postoperative immobilisation correlated with the number-of-steps-per-diem compliance (r > +0.22).
    European Journal of Trauma 01/1997; 23(5):200-204.
  • L Chen, W Klaes, S Assenmacher
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    ABSTRACT: To investigate and compare the osteogenesis of bone substitute materials. 52 Chbb: ch rabbits were divided into 5 groups. Five different porous biomaterials, including natural bovine hydroxyapatite (Bio-OSS, BK V/1), semi-synthetic coral hydroxyapatite interpore 500, synthetic tricalcium phosphate CEROS 82 and glass POROLITH, were implanted together with free periosteum into the muscle of rabbits for up to 3 and 6 weeks. Undecalcified sections were prepared for microradiography, light and UV microscopy, and morphometry. Bone ingrowth was present in all such implantats. Bone formation was limited to the periphery of the Ceros blocks, that are lack of pore interconnection, while the other 4 materials with an interconnected porous system were infiltrated by bone into the centrum. Planimetric analyses showed that the specimens were composed of 6.5%-19.0% new bone at the 3rd week and 14.2%-25% at the 6th week respectively. The difference of bone ingrowth was only significant between Bio-OSS and BK V/1 at the 3rd week. No statistically significant difference of bone volume was found within the 6 week groups. There was a positive correlation between the new bone volume and the porosity of the materials. For the bone ingrowth, the structure of the materials, specifically the pore and pore interconnections, is more impatant than the chemical composition.
    Zhonghua yi xue za zhi 08/1996; 76(7):527-30.
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    ABSTRACT: We have used total hip replacement combined with cemented intramedullary nailing to treat a selected group of nine patients with pathological fractures of the proximal femur and impending fractures of the shaft due to metastases. One patient died from cardiopulmonary failure on the third postoperative day, but the others were able to walk within the first week after operation. Complications included one recurrent dislocation of the THR and one fracture of an osteolytic lesion of the femoral shaft during nail insertion. Both were managed successfully. The hybrid osteosynthesis which we describe is an alternative to the use of tumour or long-stem prostheses; it has the advantage of preserving bone stock and muscle attachments.
    Journal of Bone and Joint Surgery - British Volume 06/1996; 78(3):400-3. · 2.69 Impact Factor
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    ABSTRACT: From 1981 to 1995, 22 patients received intercalary bone allografts for reconstruction of the extremity after en bloc tumor resection (16 malignant, six benign lesions). Solid union of the graft-host sites within 15 months occurred in 86%. The overall survival rate of patients with high-grade lesions was four of seven and with low-grade lesions eight of nine after 4.5 years. Despite the high complication rate of 42%, intercalary bone allografts provide a valuable solution for reconstruction of the extremity after tumor resection in long bones.
    Langenbecks Archiv für Chirurgie. Supplement. Kongressband. Deutsche Gesellschaft für Chirurgie. Kongress 02/1996; 113:921-4.
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    ABSTRACT: From 1981 to 1993, 21 patients received intercalary bone allografts for reconstruction of the extremity after en bloc tumor resection (15 malignant and 6 benign tumors). The allografts were collected from multiorgan donors and cryopreserved at -70 degrees C. The mean follow-up was 4.4 (range 1-13) years. The fate of the grafts was followed by conventional radiography, bone scintigraphy, and functional assessment. The overall survival rate of the 7 patients with high-grade malignancies was 86%. Solid union of the graft-host sites in less that 15 months occurred in 85%. An increased isotope uptake of the graft indicates that incorporation at the osteotomies as well as remodelling is still continuing at 9 years after operation. The overall complication rate was 43%; 3 patients had two or more complications. Complications were related to the allograft in 6 (infection or fatigue fracture in 1 and delayed healing in 4 cases) and to the osteosynthesis in 3 patients. The definitive results after treatment of complications show that satisfactory results have been obtained in all but 2 patients: 62% had excellent, 19% good, and 10% fair results. Intercalary allografts therefore provide a valuable solution for large skeletal defects after resection of bone tumors.
    Archives of Orthopaedic and Trauma Surgery 02/1995; 114(6):308-18. · 1.36 Impact Factor
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    ABSTRACT: From 1981 to 1993, 21 patients received intercalary bone allografts for reconstruction of the extremity after en bloc tumor resection (15 malignant and 6 benign tumors). The allografts were collected from multiorgan donors and cryopreserved at -70°C. The mean follow-up was 4.4 (range 1–13) years. The fate of the grafts was followed by conventional radiography, bone scintigraphy, and functional assessment. The overall survival rate of the 7 patients with high-grade malignancies was 86%. Solid union of the graft-host sites in less that 15 months occurred in 85%. An increased isotope uptake of the graft indicates that incorporation at the osteotomies as well as remodelling is still continuing at 9 years after operation. The overall complication rate was 43%; 3 patients had two or more complications. Complications were related to the allograft in 6 (infection or fatigue fracture in 1 and delayed healing in 4 cases) and to the osteosynthesis in 3 patients. The definitive results after treatment of complications show that satisfactory results have been obtained in all but 2 patients: 62% had excellent, 19% good, and 10% fair results. Intercalary allografts therefore provide a valuable solution for large skeletal defects after resection of bone tumors.
    Archives of Orthopaedic and Trauma Surgery 01/1995; 114(6):308-318. · 1.36 Impact Factor
  • K P Schmit-Neuerburg, J Hanke, S Assenmacher
    Der Chirurg 12/1989; 60(11):711-22. · 0.52 Impact Factor
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    01/1989;

Publication Stats

99 Citations
24.02 Total Impact Points

Institutions

  • 1989–2001
    • University Hospital Essen
      • Klinik für Unfallchirurgie
      Essen, North Rhine-Westphalia, Germany
  • 1996
    • Zhejiang Medical University
      • Department of Surgery
      Hang-hsien, Zhejiang Sheng, China