Search PubMed⌕ Search

Biomedical subjects

R Kotz

Publications and source records attributed to R Kotz.

At least 109 records · Page 6Linked to original sources
PubMed1987

The transtrochanteric anterior rotational osteotomy of Sugioka. Early and late results in idiopathic aseptic femoral head necrosis.

The early and late results of 39 transtrochanteric anterior rotational osteotomies of Sugioka, performed since 1975 in idiopathic aseptic necroses of the femoral head, are presented; 23 results are excellent and good. The rates of postoperative complications and reoperations are high, more than 40% each. Reoperations in smaller necrotic areas are far less frequent. There is no deterioration of the result when the hip joint is replaced by an endoprosthesis after Sugioka osteotomy. Insufficiency of the gluteus muscles is more frequent, but, on the other hand, range of motion of the hip joint increases after total hip replacement. Based on the results, we feel that there are fewer indications for this operation. The procedure is indicated for young patients with good function of the hip joint and sectors of necrosis up to 90 degrees, especially when there is not other way to remove the area of necrosis from the weight-bearing zone of the femoral head.

Adult↗
PubMed1987

[Treatment strategy of malignant bone tumors of the spine].

In patients with big, tumorous changes in the vertebral bodies, conservative measures like radiotherapy, medical therapy, and external support measures are often no longer applicable. As a result of the instability of the spinal column, most of the patients are bedridden and in great pain. Signs of root compression occur frequently, as do incipient or incomplete transverse lesions. On the one hand, these signs result from tumor growth and on the other from collapse of the vertebral bodies with kyphosis and fragment dislocation in the spinal canal. In these patients the procedure of choice is "ventral" tumor removal, decompression of the spinal cord and roots, followed by stabilization. By the "dorsal" operative method, it is not possible to overcome the major cause of the instability and pain. On the basis of the results obtained in 100 "ventral" resections of the vertebral bodies, the treatment strategy is presented, ranging from the preliminary examination to the postoperative period.

Combined Modality Therapy↗
PubMed1986

The angiographic response of osteosarcoma following pre-operative chemotherapy.

The prognosis of osteosarcoma has improved significantly with recent advances in chemotherapy. Evaluation of the effect of chemotherapy is important for optimal timing of surgery, for selecting an alternative drug regimen in instances of poor response to chemotherapy and for testing combinations of new drugs. The purpose of this paper is to define the value of plain radiographs and angiography in assessing tumor response to chemotherapy. Studies were obtained before and after chemotherapy. The radiographic results were correlated with histologic evaluation of the resected specimen. Patients with less than 10% residual viable tumor in the resected bone were designated "responders" and patients with more than 10% of remaining viable tumor were "nonresponders". Angiographic appearances correctly separated 15 patients with good response to chemotherapy from seven patients who were not responsive. Conversely, comparison of plain radiographs obtained before and after chemotherapy did not allow a reliable differentiation between patients with good, poor, or no response to chemotherapy. The current role of angiography in the management of patients with osteosarcoma is discussed. It is concluded that - in contrast to plain film radiography - angiography is an accurate method for assessing the response of osteosarcoma to chemotherapy.

Adolescent↗
PubMed1986

Fractures of the proximal femur in patients with total hip endoprostheses.

Between October 1982 and October 1983 three patients were admitted to the Orthopedic Clinic of the University of Vienna who had suffered complicated fractures of the proximal femur, with concomitant loosening of previously implanted total hip endoprostheses. To replace them we used the KMFTR Endoprosthesis. The Kotz Modular Femur and Tibia Reconstruction Endoprosthesis was originally developed for the surgical management of bone tumors. The implantation followed the principle of intramedullary splinting and transfer of force. Fragments of bone adhering to the surrounding muscles were positioned around the endoprosthesis and the periosteum was carefully reconstructed. After a follow-up period of 1 year on the average the patients were very content with the results and were essentially not restricted in their scope of activities. Walking capacity and mobility were satisfying at last checkup. Radiographically, a consolidation of the femur with solid bony incorporation and a firm fit of the prosthesis were observed.

Aged↗
PubMed1986

A modular femur-tibia reconstruction system.

A 26 piece modular system for the reconstruction of the bones of the lower extremity from the femoral head to the distal third of the tibia is described. This modular system can be implanted without cement and allows for the intraoperative determination of the amount of resection necessary. The implant material is the well-known cast, Co-Cr-Mo alloy Vitallium. From 1982 to the end of 1985, 52 patients were treated with this cementless tumor endoprosthesis of the Kotz Modular Femur-Tibia Reconstruction System (KMFTR) at the University of Vienna, Department of Orthopedics. The locations of the tumors were: proximal femur (28), distal femur (17), and proximal tibia (7). In two cases a total femur was implanted and in another patient a total knee. Indications for the resection of the bone segments and joints concerned included primary bone tumors, metastases, and loosening of conventional endoprostheses and tumor resection endoprostheses. Twenty-one patients with an average follow up of 20.4 months and a minimum follow up of 1 year were evaluated according to Enneking's criteria. Eight patients had proximal femoral replacement. The results were excellent in two, good in five, and fair in one. Eleven patients had undergone replacement surgery in the knee joint area. The overall rating showed five excellent results, four good and two fair. One patient with a total femoral replacement had multiple bone metastases with polytopic pain and was no longer available for regular assessment. Another patient with a total knee replacement suffered a rupture of the patellar ligament after 10 months and had to be revised. Radiologically we have observed excellent bone incorporation of the prosthesis in 15 of 25 evaluated patients. Ten cases showed no changes in radiologic features as compared to the initial findings. These were patients with short follow up periods. Although complications did occur in these major surgical interventions, the final results were very satisfactory and the patients were subjectively content with the operation.

Adolescent↗
PubMed1985

[Operative therapy of dysphagia caused by cervical spondylophytes].

This study reports two cases of anterior osteophytes that caused dysphagia leading to loss of weight and finally cachexia. The successful ablation of these osteophytes and clearance of the intravertebral spaces with ventral fusion of the cervical spine completely relieved these two patients of their swallowing difficulties.

Aged↗
PubMed1984

Neoadjuvant chemotherapy for osteogenic sarcoma: results of a Cooperative German/Austrian study.

From December 1979 to August 1982 158 patients were registered for an adjuvant chemotherapy (CT) study COSS -80. To compare the effect of cisplatin (CPL) to that of the drug combination bleomycin, cyclophosphamide, and dactinomycin (BCD), patients were randomized to receive either drug(s) within a course of sequential multidrug CT including doxorubicin and high-dose methotrexate (HDMTX). Definite surgery was done 10-18 weeks after the start of CT. Patients were randomized a second time to receive or not to receive fibroblast interferon in addition to CT beginning at week 16. At a median observation time of 19.5 months (range, 4-34 months), 116 (73%) of 158 patients were continuously disease-free (CDF). After exclusion of 42 patients because of some deviation in history and/or management, 86 (74%) of 116 patients actually were CDF with a 30-month calculated CDF-rate of 68%. There was no difference in CDF rates in the patients receiving BCD versus CPL or receiving interferon versus no interferon. Whereas, in comparison to the previous study COSS -77, the over-all increase in CDF rate does not reach statistical significance, it does, however, for the younger (less than or equal to 12 years) and for male patients, which is assumed to be the effect of increasing the methotrexate dose from 6 to 12 g/m2 in the COSS -80 study.

Adolescent↗
PubMed1983

Adjuvant chemotherapy in osteosarcoma - effects of cisplatinum, BCD, and fibroblast interferon in sequential combination with HD-MTX and adriamycin. Preliminary results of the COSS 80 study.

In a cooperative adjuvant chemotherapy study of osteosarcoma (COSS-80), 192 patients were registered from December 1979 to March 1982. Forty-one patients have been excluded from study because of their nonadjuvant situation, therapy-limiting clinical conditions, or inadequate diagnosis. One hundred and fifty-one patients have been randomized to receive either the drug combination bleomycin + cyclophosphamide + dactinomycin (BCD) or cisplatinum (CPL) within a course of sequential multidrug chemotherapy including adriamycin (ADR) and high dose methotrexate (HDMTX). After exclusion of 51 patients with some deviation in history and/or management 100 selected patients were randomized once more to receive in addition or not fibroblast interferon after preoperative chemotherapy and surgical removal of the primary tumor. Patients were stratified for age and sex and for site and extension of tumor as well in both randomizations. Median follow up is now 12 (1-16) months. The expected 2-year disease free survival (DFS) rate of the total doubly randomized group is 78% and of the single randomized group 76%. No difference could be discerned between recombined groups receiving BCD vs CPL or interferon vs no interferon. The effect of preoperative chemotherapy on the tumor was evaluated clinically and by histopathologic grading; 66/85 (78%) patients were judged clinically as responders with pathohistologic verification of this finding in 71% of these cases. No adverse effect arose from delaying definite surgery for preoperative chemotherapy, but initial application of chemotherapy as well as planning, preparing, and performing of the surgical procedure have been facilitated. The majority of patients received some kind of limb-salvage treatment without local recurrences so far. A statistically insignificant but intriguing tendency for a slightly higher incidence of pulmonary metastases after resection as opposed to amputation could be detected. Similar to observations in the previous study COSS-77.

Adult↗
PubMed1983

Possibilities and limitations of limb-preserving therapy for bone tumors today.

To sum up, modern resection and extremity-preserving therapy is characterized by the following aspects: (1) The surgical procedure must be appropriate for the stage of the tumor. (2) From a functional point of view, the results of the resection treatment have so far been encouraging. (3) In spite of considerable technical progress, the implantation of bone-replacement endoprostheses as a treatment for primary osteosarcoma of the extremities must still be considered to be at the experimental stage.

Adolescent↗
PubMed1983

[Functionally satisfying reconstruction of a combined abdominal, chest wall and diaphragmatic defect with corium following sternum tumor resection].

In a patient, suffering from a chondrosarcoma in the lower sternum, and having undergone radical tumor resection, we had to reconstruct the thoracic wall, the abdominal wall, and the diaphragm. This was done with autologous corium. We report on the advantages of this material and at the same time refer to that of a complete physiologic reconstruction of the diaphragmatic dome seems impossible if accompanied by defects of the thorax and the abdominal wall. Fitting a corset appears necessary as an external support.

Abdominal Muscles↗
PubMed1982

[Surgical therapy of malignant bone tumors and results of the treatment].

The surgical management of bone metastases should relieve pain and improve function. Of the operative cases (170 in the last 10 years), 30% underwent resectional therapy with successful implantation of an endoprosthesis. Surgical management of primary malignant bone tumors should result in cure. Since 1976, in 44 of 54 cases of osteosarcoma a tumor resection was performed and in 40 cases the operation was adequate. A rotation plasty operation was performed in 15 of the 44, a tumor endoprosthesis was implanted in 22, and other methods were used in seven.

Bone Neoplasms↗
PubMed1982

[Interferon/Controlled study in 3-year survival of patients with osteosarcoma (author's transl)].

In eight patients with osteosarcoma we conducted a controlled tolerance study with human lymphoblast interferon. Interferon was applied for 12 months and the control period after stopping interferon has lasted 12-42 months up to now. 4 out of 8 patients who received interferon did not show any adverse reaction concerning clinical and laboratory tests during the course of a 1-year application and during the follow-up period, resp. Only reversible thrombopenias and an increase in the alpha 2-globulins fraction were observed in the interferon and in the control group, resp. All of the 8 patients have up to now survived tumor-free.

Adolescent↗
PubMed1982

Rotation-plasty for childhood osteosarcoma of the distal part of the femur.

A rotation-plasty procedure was used in four children with osteosarcoma of the distal part of the femur. The results showed that this procedure, combined with en bloc wide excision of the proximal part of the tibia and the distal part of the femur including the knee joint, appears to be an adequate surgical treatment for osteosarcoma of the distal part of the femur in children. None of our patients to date had either clinical or radiographic evidence of local recurrence during follow-up periods of between twenty-seven and fifty-eight months. One patient, however, died of widespread metastatic disease. Despite postoperative adjuvant chemotherapy with high doses of methotrexate, there have been no problems with wound-healing and early fitting of a prosthesis was possible. Because of the success in preventing local recurrence in these four patients, we now generally employ this method in the surgical management of osteosarcoma of the distal part of the femur in children.

Artificial Limbs↗