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Biomedical subjects

R Kotz

Publications and source records attributed to R Kotz.

At least 55 records · Page 3Linked to original sources
PubMed1999

Local and systemic control after ablative and limb sparing surgery in patients with osteosarcoma.

Limb salvage surgery in patients with osteosarcoma is reported to cause a higher rate of local recurrences with a poorer chance of survival. It was the aim of the study to analyze differences between ablative and limb sparing surgery in patients with osteosarcoma who are treated with chemotherapy with respect to local and systemic tumor control and to determine independent prognostic factors. One hundred thirty consecutive patients younger than the age of 21 years who were operated on at the authors' institution for osteosarcoma of the extremities were reviewed. Histologic evaluations of surgical margins according to Enneking and coworkers revealed mostly wide (n = 109) and radical (n = 10) resection margins. The 5-year disease free survival rate was 60% for those patients treated by amputation and 71% for those treated by limb salvage. The overall local recurrence rate was 2.3%; 4.3% for ablation but only 1.2% for limb sparing surgeries. Multivariate analysis showed an independent effect of tumor volume, response to chemotherapy, and as expected, metastases at the time of diagnosis on overall survival. These data indicate that in patients where wide or radical tumor resection can be achieved, no difference in the outcome between ablative and limb sparing surgery occurred in local and systemic tumor control.

Adolescent↗
PubMed1998

[Bone lengthening and soft tissue correction using the Ilizarov technique].

From March 1989 to September 1995 at the Department of Orthopedic Surgery at the Vienna General Hospital 31 limb-lengthenings or corrections of the soft-tissue (contractions of joints, clubfeet) using the Ilizarov method were performed. 15 patients have already finished growth. All complications were analysed according to Paley's classification. The tibia-group (n=13) reached an average lengthening of 3.5 cm (2-5.7 cm) [16% (6-35%) of the initial length] with a healing index of 1.7 mo/cm and a complication rate of 42%. In the femur-group (n=8) a mean lengthening of 5.4 cm (2.5-9.4 cm) [21% (7-34%) of the initial length] could be achieved with a healing rate of 1.3 mo/cm and a complication rate of 40%. The ulna-group (n=3) reached an average lengthening of 2.6 cm (2.2-3.4 cm) [21% (17-24%) or the initial length] with a healing index of 1.4 mo/cm and a complication rate of 17%. The knee contracture group (n=2) was free of complications. The Ilizarov technique has been performed successfully in a high percentage although extensive elongations reported by Ilizarov could not be achieved neither by us nor by other authors. The above-mentioned method has been proved to be efficient and successful to correct deformities of the soft-tissue.

Adolescent↗
PubMed1998

[Primary malignant bone tumors. Clinical aspects and therapy. Vienna Bone Tumor Registry].

Diagnosis, concepts of therapy and prognosis of primary malignant bone tumors require intensive cooperation between orthopedic surgeons, radiologists and pathologists with special knowledge in oncology. The present paper demonstrates relevant topics of diagnosis, radiological appearance and therapy of the osteosarcoma, Ewing's sarcoma, chondrosarcoma and malignant fibrous histiocytoma based on the material of the Vienna Bone Tumor Registry and more than 35 years of cooperation between the Institute of Pathology and Anatomy and the Department of Orthopedics at the University of Vienna.

Bone Neoplasms↗
PubMed1998

[Surgical therapy of spinal metastases].

Bone metastases of the vertebral spine occur frequently after breast cancer, hypernephroma or thyroid carcinoma. Located commonly in the lumbar and thoracic spine, half of the lesions are found in the vertebral body, but in many cases lamina and pedicles are also involved. Pain resistant to conservative treatment, vertebral compression fracture and segmental instability, together with progredient neurologic deficits and para- or tetraplegia, all make operative intervention mandatory. In this article dorsal decompression and stabilization are compared to ventral decompression and compound osteosynthesis. Segmental stability and life-time prognosis of the patient are important factors to decide on the best surgical procedure. Dorsal decompression without stabilization should only be performed as a palliative procedure in patients with an inoperative tumor, poor prognosis, or if the estimated postoperative segmental stability seems to be sufficient. In cases of a solitary metastasis, after radical resection of the primary tumor and when the prognosis is good total vertebrectomy can be performed. In addition to surgical treatment, adjuvant chemotherapy and/or radiation therapy should be performed in a multidisciplinary setting.

Bone Plates↗
PubMed1998

Teicoplanin in the prevention of infection in total hip replacement.

Perioperative antibiotic prophylaxis has been shown to be effective in reducing postoperative wound infections. The rising incidence of infections secondary to methicillin-resistant strains of Staphylococcus aureus. S. epidermidis and S. enterococcal prompted us to administer Teicoplanin to infection in elective total joint arthroplasty. In 111 patients Teicoplanin was given in a single intravenous dose of 10 mg/kg prior to surgery. In the postoperative period no deep infection of the prosthetic device was found in a 14-month follow-up. In two patients the following organisms were isolated from superficial infections of the wound: S. epidermidis (methicillin-sensitive), Pseudomonas aeruginosa, and Enterobacter sp. In no patient was revision surgery necessary. The serum concentration of Teicoplanin was within the therapeutic range during surgery, and tissue levels of Teicoplanin in cancellous (6.2 mg/kg, range 3.8-10.9 mg/kg) and cortical (7.1 mg/kg, range 2.6-12.1 mg/kg) bone during surgery in 16 patients exceeded the minimum inhibitory concentration of 90% (MIC90) of methicillin-resistant strains reported for methicillin-resistant strains. In our experience a single dose regimen of Teicoplanin is a safe and effective method of antibiotic prophylaxis in hip joint replacement, particularly when methicillin-resistant bacteria are present.

Acetabulum↗
PubMed1998

Evidence for the involvement of the hydroxyl radical in the pathogenesis of excessive connective tissue proliferation in patients with tumor-endoprostheses.

Extensive proliferation of connective tissue around Vitallium implants can be observed in young patients who had limb salvage for primary malignant bone tumors. The underlying mechanism of excess proliferation and collagen accumulation is not known. We were therefore interested to show whether the alloy of the implant induced proliferation of fibroblasts in vitro, acted by a cytotoxic mechanism or generated free radical cross linking of collagen with subsequent accumulation. In vitro tests for proliferation and cytotoxicity using the implant material which consists of a series of transition metals, ruled out a proliferation-inducing or cytotoxic effect of the implant. Determination of ortho-tyrosine (OT), a marker for hydroxyl radical attack on phenylalanine, in the proliferating tissues surrounding the implants revealed significantly higher aromatic hydroxylation in the vitallium surrounding tissue correlating with tissue collagen content (r = 0.86, p < 0.01). Based upon the findings of increased OT and the presence of higher molecular weight bands on SDS-PAGE, representing more cross linked collagen, we suggest that hydroxyl radical attack lead to free radical mediated cross linking of collagen with subsequent collagen accumulation, as collagen cross-linked to a higher degree is less susceptible to proteolytic degradation.The hydroxyl radical attack seems to having been generated by the many transitional metals of the vitallium-alloy.

Adolescent↗
PubMed1998

Heat shock protein 72 expression in osteosarcomas correlates with good response to neoadjuvant chemotherapy.

Although the therapeutic outcome of osteosarcoma patients has improved dramatically within the last 20 years because of combined neoadjuvant chemotherapy and surgery, the problem of drug resistance remains. Thus far, markers that can predict the response to chemotherapy at the time of biopsy are not available. Heat shock proteins (hsp) 60, 72, and 73 have been shown to play a role in tumor immunity, and our study investigated their expression in human osteosarcomas and nonmalignant bone tumors before neoadjuvant chemotherapy. Immunohistochemical evaluations of hsp expression was performed on paraffin-embedded sections of 45 patients (17 female, 28 male, aged 6.5 to 62 years; mean, 19.4 years) with high-grade osteosarcoma at the time of biopsy, before preoperative chemotherapy. These results were correlated to histological response to chemotherapy, tumor size, age, alkaline phosphatase serum levels, and duration of symptoms. Thirty-four patients (15 male, 19 female, mean age 27 years) with osteoblastoma, osteoid-osteoma, or fibrous dysplasia served as nonmalignant controls. Hsp60 was uniformly found in the cytoplasm of both benign and malignant bone tumors. Nuclear hsp73 expression quantitatively increased in osteosarcoma cells. Hsp72 was significantly overexpressed in osteosarcomas (17 of 45, 38%) compared with nonmalignant bone tumors (1 of 34, 2.9%; P < .001). Hsp72-positive osteosarcomas responded better to neoadjuvant chemotherapy than hsp72-negative cases (P < .001), co-express hsp60, and correlate with higher tumor size (P < .005) and location in the distal femur. No differences were observed relative to age, gender, duration of symptoms, alkaline phosphatase levels, or hsp73 expression between hsp72-positive and hsp72-negative tumors. Hsp72 expression seemed to be a predictive immunohistochemical marker for osteosarcoma, because it is the first marker to prospectively correlate to response to neoadjuvant chemotherapy. It therefore, may be of importance in preoperative therapy regimens for nonresponding high-risk patients.

Adolescent↗
PubMed1998

Evaluation of HLA-DR expression and T-lymphocyte infiltration in osteosarcoma.

Although in recent years the outcome of patients with osteosarcoma has considerably been improved by combining neoadjuvant chemotherapy with radical surgery, there still remains the problem of nonresponse to chemotherapy. T-lymphocytes play a critical role in tumor immunology, and MHC molecules are of central importance in the regulation of the immune response. It is the aim of this study to investigate whether T-lymphocyte infiltration of osteosarcomas and HLA-DR expression on tumor cells and infiltrating immune cells are of predictive or diagnostic value. Expression of CD3, CD8 and HLA-II was evaluated immunohistochemically on paraffin-embedded sections of 35 patients with high-grade osteosarcoma at the time of biopsy before chemotherapy and correlated with histologic response to chemotherapy, tumor size, age, alkaline-phosphatase serum levels and duration of symptoms. Thirty-four patients with osteoblastoma (n = 7), osteoid osteoma (n = 7) or fibrous dysplasia (n = 20) served as controls. Osteosarcomas were infiltrated by CD3+ (33/35, 95%) and CD8+ T-lymphocytes (24/35, 68%), non malignant bone tumors by CD3+ in 91% (31/34) and CD8+ T-lymphocytes in 74% (25/34), respectively. T-lymphocytes were positive for HLA-DR expression in 29% (10/35) in osteosarcomas and in 11% (4/34) in non-malignant controls. Osteosarcoma cells were positive for HLA-DR in 11/35 (31%) and non-malignant tumor cells in only 9% (3/34). Therefore, HLA-DR is overexpressed in osteosarcoma (p < 0.05). HLA-DR expression on osteosarcoma cells showed a positive correlation with HLA-DR expression on lymphocytes (p < 0.001) as well as with duration of symptoms and age (p < 0.05). Response to preoperative chemotherapy, gender, tumor size and serum alkaline-phosphatase levels did not correlate with the expression of the molecules tested. Our results show that HLA-DR is overexpressed in osteosarcoma cells compared to non-malignant bone-tumors. This overexpression, however, fails to serve as a predictive marker for response to neoadjuvant chemotherapy. The same is also true for tumor-infiltrating lymphocytes expressing CD3, CD8 and HLA-DR. Increased HLA-DR expression in osteosarcoma is most likely due to the immune response against the tumor.

Adolescent↗
PubMed1998

Long-term results of the co-operative German-Austrian-Swiss osteosarcoma study group's protocol COSS-86 of intensive multidrug chemotherapy and surgery for osteosarcoma of the limbs.

BACKGROUND: In an effort to intensify osteosarcoma therapy, systemic ifosfamide was added pre- and postoperatively to an already aggressive three-drug regimen. In a subgroup of patients, loco-regional treatment intensification was attempted by using the intraarterial route to give cisplatin. PATIENTS AND METHODS: Patients < or = 40 years at diagnosis of a localised, de novo high-grade central extremity osteosarcoma were eligible for inclusion into study COSS-86 if registered within three weeks from biopsy. Doxorubicin, high-dose methotrexate, and cisplatin were given to all patients. Patients who fulfilled one or more of three defined high-risk criteria received early systemic treatment intensification by adding ifosfamide as the fourth agent. Preoperatively, these high-risk patients received cisplatin either intraarterially or intravenously. RESULTS: 171 eligible patients were entered, of which 128 were stratified into the high-risk group. When all 171 were analysed by intention-to-treat, actuarial overall and event-free survival rates at ten years were 72% and 66%, respectively. No benefit of intraarterial cisplatin application was detected. Cumulative treatment toxicity was considerable. CONCLUSIONS: In a multicenter setting, intensive treatment of osteosarcoma according to protocol COSS-86 led to long-term disease-free survival for two thirds of patients. We saw no benefit of using the intraarterial route to administer cisplatin.

Adolescent↗
PubMed1998

[Results of interdisciplinary sacrum resection in sacral recurrence of rectal carcinoma].

The authors present a retrospective analysis of 12 consecutive patients surgically treated with curative intention for recurrent rectal cancer involving the sacrum. After radical partial sacral resection--extended resection in seven cases--the operative mortality rate was zero, postoperative long-term survival was reached in 17%, while effective palliation of pain was achieved in all cases. Nevertheless, 50% did not survive more than 1 year after the operation. The overall mean survival time was 22 months. Sacral recurrence can be resected safely and potentially curatively after careful patient selection.

Combined Modality Therapy↗
PubMed1997

The benefits of surgery in the treatment of pelvic metastases.

This retrospective study analyses the benefit of surgery to patients with pelvic metastases. Forty-three patients were operated on between 1980 and 1992, 37 having intralesional and 6 extralesional resections. Thirty-nine had perioperative adjuvant therapy. Survival time was calculated by the Kaplan-Meier method. Clinical evaluation used the Karnofsky performance status which showed improvement from 55% before operation to 74% at 3 months (p = 0.0001) and 77% after 6 months (p = 0.0001). Those having an intralesional resection had a median survival time of 13 months, a complication rate of 24% and a local recurrence rate of 19%. The comparable figures for those with extralesional resection were 16 months survival, complications in 3 out of 6, and no local recurrences. The quality of life was improved by operation and intralesional resection is preferable in most of these patients.

Adult↗
PubMed1997

One-stage revision surgery for infected megaprostheses.

We have reviewed the results of one-stage revision surgery in 18 patients for infection of megaprostheses implanted after the resection of malignant bone and soft-tissue tumours. At a mean follow-up of 52.0 +/- 35.0 months (18 to 135) infection was eliminated in 14 of the 18 patients. The infection-free patients showed no abnormal tests for inflammation and had a mean Enneking score of 20.6 +/- 5.0 points (maximum 30 points). We suggest that one-stage revision without exchange of the anchorage parts is justified in patients with megaprostheses infected by antibiotic-sensitive micro-organisms.

Adolescent↗
PubMed1997

Elevated serum cobalt with metal-on-metal articulating surfaces.

We determined serum cobalt levels in 55 patients by atomic absorption spectrophotometry before and after implantation of uncemented total hip arthroplasties. In a randomised, prospective trial 27 wrought Co-28Cr-6Mo-0.2C metal-on-metal articulations were compared with 28 ceramic-on-polyethylene hips which did not contain cobalt. Other sources of iatrogenic cobalt loading were excluded. The metal-on-metal group produced detectable serum cobalt levels (median 1.1 microg/l after one year) which were significantly different (p < 0.0001) from those of the ceramic-on-polyethylene control group (median below detection limit of 0.3 microg/l after one year). Our findings indicate that metal-on-metal bearings generate some systemic release of cobalt.

Adult↗
PubMed1997

Short term prophylaxis against heterotopic bone after cementless hip replacement.

The aim of the current study was to reveal whether 7 days of indomethacin treatment sufficiently prevents heterotopic ossification after cementless total hip arthroplasty. One group received indomethacin for 14 days (n = 102), and the second for 7 days (n = 99) after cementless total hip arthroplasty. At followup 1 year postoperatively, the average Harris Hip Score was 91 points in the 14-day treatment group and 89 points in the 7-day treatment group. The incidence of heterotopic ossification as outlined by Brooker was similar in both groups. Ninety-six patients in the 14-day treatment group had heterotopic ossification Grades 0 or 1, and 6 patients had Grade II heterotopic ossification; whereas in the 7-day treatment group, 95 patients had Grades 0 or 1 heterotopic ossification and 4 patients had Grade II ossification. None of the patients had Grades III or IV heterotopic ossification. In the 14-day treatment group, headache, dizziness, or gastritic disorders develop in 10 patients, and in the 7-day treatment group, 7 patients had these effects. This study shows that treatment with 100 mg indomethacin daily for 7 days is not significantly different than 14 days of treatment for the prevention of formation of severe heterotopic ossification after cementless hip arthroplasty.

Adult↗
PubMed1996

Vascular reconstruction for limb salvage in sarcoma of the lower extremity.

OBJECTIVES: To examine the patency and limb-salvage characteristics of vascular reconstruction in patients with sarcomas of the lower extremity who had been treated with limb-preserving resection and to examine patient survival during a long follow-up period. DESIGN: Retrospective cohort study. SETTING: University hospital, tertiary referral center. PATIENTS: From 1984 to 1992, 14 patients underwent limb-preserving resection of sarcomas in the proximal lower extremity, with 20 vascular reconstructions performed. OUTCOME MEASURES: Color Doppler scans documented patency of the vascular reconstructions. Clinical evaluation included functional results in terms of limb movement and quality of life. Local tumor control and systemic recurrence were examined by repeated radiologic examination. Overall survival as well as time and cause of death were assessed. RESULTS: A total of 13 patients had patent vascular grafts, while the venous graft became occluded in 1 patient. Limb function was rated as excellent or good in 9 patients, as fair in 3, as poor in 1, and could not be clinically estimated in 1. Postoperative thrombosis of the venous graft was detected in 3 patients and was effectively managed by thrombectomy in 2. Three patients underwent reoperation because of hematoma or complications caused by local infection. The tumor endoprosthesis had to be replaced in 3 patients. During follow-up periods that ranged from 15 to 132 months (mean, 55 months), 4 patients died. In all of these patients the cause of death was systemic recurrence in the lung. Two additional patients developed pulmonary metastases, but at the time of this report, they were still alive as long as 132 months after operative resection or chemotherapy. No local recurrence was found. CONCLUSION: Limb-preserving resection of sarcoma of the lower extremity can be performed with satisfactory function of the limb maintained, even if it becomes necessary to resect the femoral vessels. Autologous venous graft for vascular reconstruction is the treatment of choice. In spite of the high incidence of metastases, considerable long-term survival is possible.

Adolescent↗
PubMed1996

Latex rubber condoms: predicting and extending shelf life.

Condoms from five manufacturers were subjected to controlled exposures of heat, humidity, and air and to different natural environments in five countries. Under aerobic conditions (condoms in permeable packages or unpackaged), stress properties declined. The relationship between rate of decline as a function of temperature was quadratic. Under oxygen-restricted conditions (foil-wrapped packages) at average storage temperatures of 30 degrees C and lower, strain properties declined with little or no significant change in stress properties. The effect is to cause condoms to become stiffer; high-breakage rates in use have been correlated with product stiffening. A new rationale for accelerated-aging tests to predict condom shelf stability is suggested, including a test to control the trend of condoms to stiffen. Silicone lubricant, impermeable packaging, and inclusion of antioxidants in the condom formulation can prevent or minimize aerobic breakdown of latex condoms. Specifying low-modulus condoms can prevent excessive stiffening.

Air↗
PubMed1996

Prevention of chemotherapy-induced anemia by the use of erythropoietin in patients with primary malignant bone tumors (a double-blind, randomized, phase III study).

BACKGROUND: Patients undergoing chemotherapy for treatment of malignancy frequently experience clinically significant anemia. Myelosuppressive chemotherapy impairs erythropoiesis, which may not fully recover between treatment cycles. Recombinant human erythropoietin (rHuEPO) has been effectively introduced in anemic patients suffering from chronic renal failure. The present study was designed to assess, first, whether rHuEPO treatment decreases transfusion requirements in chemotherapy-induced anemia and, second, whether high-dose rHuEPO application is safe. STUDY DESIGN AND METHODS: Thirty consecutive anemic patients (hemoglobin <11 g/dl) receiving combination chemotherapy for primary malignant bone tumors were studied in a prospective, double-blind, randomized, Phase III trial. Patients received chemotherapy according to one of two German protocols, depending on histologic diagnosis. All subjects enrolled were randomly assigned either to receive 600 IU of rHuEPO per kg of body weight intravenously twice a week or to receive a placebo during chemotherapy. To obtain comparable data, an observation period of 20 weeks was chosen. Twenty-nine patients fulfilled the criteria and were eligible for statistical evaluation. RESULTS: Transfusion requirements were significantly decreased from Week 8 of therapy (p<0.05) in the treatment group. Therapeutic benefits were even more evident with continuation of therapy (Week 12, p = 0.03; Week 16, p = 0.016; Week 20, p = 0.002). The blood required was 2.1 units of red cells in the treatment group and 8.4 units of red cells in the placebo group. All patients tolerated rHuEPO with no serious side effects. CONCLUSION: These findings suggest that rHuEPO is an effective and well-tolerated therapeutic option for decreasing the transfusion requirements in chemotherapy-induced anemia.

Adolescent↗