Biomedical subjects
F H Sim
Publications and source records attributed to F H Sim.
Hemangioendothelial sarcoma.
Explore the source record for details and available documents.
Dedifferentiated chondrosarcoma. A report of the clinicopathological features and treatment of seventy-eight cases.
Dedifferentiated chondrosarcoma is a highly malignant variant of chondrosarcoma. Approximately 11 per cent of chondrosarcomas can be expected to dedifferentiate into more anaplastic lesions. In this report, we analyze the clinicopathological features and treatment of seventy-eight lesions of this type. The ages of the patients ranged from nineteen to eighty-two years (average, 54.6 years). The cartilaginous precursor was central in most patients. Eleven of the lesions developed in the site of a previously resected low-grade chondrosarcoma. Dedifferentiation was from low-grade chondrosarcoma to osteosarcoma in forty-two patients, to fibrosarcoma in thirty-three, and to malignant (fibrous) histiocytoma in three. Perforation of the cortex and a soft-tissue mass were found in most of the patients. Widespread metastatic disease within two years after resection was a frequent finding. The over-all five-year-survival rate was 10.5 per cent. Any potential for a "cure" is related to early diagnosis and adequate surgical treatment by amputation or resection.
Magnetic resonance imaging of osteosarcomas. Comparison with computed tomography.
This study was done to describe the magnetic resonance imaging (MRI) characteristics of osteosarcomas and to determine the clinical usefulness of MRI in the evaluation of patients with these tumors. Ten patients with osteosarcomas were examined with a Picker MRI scanner (0.15 Tesla resistive magnet). All had computed tomograms available for comparison. For demonstrating tumor extent in marrow, MRI was superior to computed tomography (CT) in 60% and about equal to CT in 40%. For defining soft tissue mass, MRI was superior to CT in 40% and about equal to CT in 60%. Direct sagittal and coronal images on MRI and superior contrast differences between tumor and normal tissues with MRI were the reasons for the advantage of MRI in these instances. CT was superior in all cases for demonstrating calcifications. Overall, MRI is better than CT for defining local extent of osteosarcomas. It is of greatest value in the peripheral skeleton, in the medullary canal, and in soft tissues.
Osteosarcoma of the spine.
Primary osteosarcoma of bone has originated in the spine in only a few patients. This report concerns twenty-seven of thirty patients who had the original diagnosis made and surgical treatment, if any, performed at the Mayo Clinic. The patients' ages ranged from eleven to eighty years. Pain in the area of involvement was the first symptom in all patients. In addition, nineteen patients (70 per cent) had neurological symptoms and signs when they were first seen. All patients had a surgical biopsy of the lesion, often combined with decompressive laminectomy. Twenty-one of the twenty-seven patients received postoperative radiation therapy in various dosages. Only five patients received adjunctive chemotherapy. All but one patient died of the disease, with a median length of survival of ten months (range, one to thirty-eight months). Although rare, osteosarcoma of the spine can usually be suspected on roentgenograms, and then the most aggressive therapy is justified.
Giant-cell tumor of bone.
Our experience involving 221 consecutive patients with giant-cell tumor who were treated from 1960 to 1982 is reported. Of one group of 146 patients, twenty-seven who were initially treated by wide resection and 112 who had thorough curettage had a recurrence rate of 23 per cent after an average length of follow-up of seven years. All thirty-three recurrences were noted less than six years after operation, and twenty-seven were noted within the first three years postoperatively. Over-all, the type of surgical removal was the most significant factor in recurrence. The recurrence rate was 34 per cent in the patients who had curettage of the lesion and 7 per cent in those who had a wide resection. In a second group of seventy-five patients, initially treated by us for a recurrent tumor, there were fifteen subsequent recurrences, after an average length of follow-up of seven years. Curettage and bone-grafting, with preservation of function of the joint, is the preferred treatment for most patients.
Osteosarcoma: state of the art.
Explore the source record for details and available documents.
Secondary malignant giant-cell tumor of bone. Clinicopathological assessment of nineteen patients.
Twenty-six patients who had a malignant giant-cell tumor of bone--a sarcoma either juxtaposed to a zone of typical benign giant-cell tumor or occurring at the site of a previously documented benign giant-cell tumor--have been seen at the Mayo Clinic. Of the twenty-six tumors, nineteen were secondary to a previous attempt at local control of a benign giant-cell tumor. All but one of these nineteen patients with a secondary tumor had received therapeutic irradiation four to thirty-nine years earlier. The nature and duration of the symptoms and the sites of predilection of the malignant giant-cell tumors were the same as for benign giant-cell tumor. Fibrosarcoma occurred three times as frequently as osteosarcoma. The best results of treatment of the secondary sarcoma were obtained with early ablation.
Titanium fibermetal segmental replacement prostheses. A radiographic analysis and review of current status.
Thirteen patients with titanium fibermetal segmental bone/joint prostheses at a minimum follow-up period of six months were reviewed. Detailed radiographic data were analyzed quantitatively in terms of stem/bone interface radiolucency and bone bridging over the segmental portion of the prosthesis at predefined zones. Although stem radiolucent lines were common in this series, only one case had clinical loosening and required reoperation. There were two cases of stem fracture; one achieved extracortical bone union without revision, and the other case required implant removal and revision. Analysis of the retrieved specimen revealed histologic evidence of bony ingrowth. The use of a long side plate for initial implant fixation might have been partially responsible for this complication because of inhibition of new bone formation over the porous-coated segment. Sequential study of radiograms at different follow-up time periods with the same zonal analysis criteria revealed that no progression of radiolucency occurred at the bone/prosthesis interface, and bone formation over the segmental portion either increased or stabilized with time. The patients' functional results and implant performance seemed to indicate that the porous-coated segmental prosthetic system was effective in bridging skeletal/joint defects. However, further improvements are needed in prosthetic design and implant quality control in order to minimize device-related complications.
Is the BANS concept for malignant melanoma valid?
In this study of 427 patients with stage I malignant melanoma seen at the Mayo Clinic between 1973 and 1981, only those patients with complete data with respect to thickness and level of penetration of lesion, morphologic type, and anatomic site were included. Although supporting the widely accepted concept of the prognostic importance of thickness of the lesion, the level of penetration was of much lesser significance in our series, and prophylactic node dissection could not be shown to be of significant benefit. Likewise, the BANS concept proposed by Day et al [1] was not corroborated. The reasons for these discrepancies are not fully apparent, although a preponderance of thin and intermediate thickness lesions in our patients may have had some influence on our results.
Synovial proliferative disorders: differential diagnosis.
The proper treatment of synovial proliferative disorders depends on an accurate diagnosis and a knowledge of the natural history of these afflictions. A simple classification of the major synovial disorders with a brief general description of each, highlighting the prominent clinical features, is helpful. A thorough history and physical examination should enable the clinician to categorize the nature of the synovial disorder. Further evaluation and consultation can then be directed within the appropriate category. Radiologic, laboratory, and microscopic studies aid in arriving at a definitive diagnosis. Once a diagnosis has been established, therapy or further evaluation can be instituted.
Synovial proliferative disorders: role of synovectomy.
Synovectomy is an effective procedure in many of the synovial proliferative diseases. It is the treatment of choice in pigmented villonodular synovitis and synovial chondromatosis. In addition, it may be a useful adjunct to treatment in carefully selected patients with rheumatoid arthritis and hemophilia. Synovectomy can now be accomplished effectively with arthroscopic techniques, and this has greatly diminished the previous morbidity and cost associated with open synovectomy. However, the indications for synovectomy remain the same, regardless of the technique.
Bone tumors: magnetic resonance imaging versus computed tomography.
The magnetic resonance (MR) imaging characteristics of bone tumors are described and the clinical utility of MR imaging in patient evaluation is reported. Fifty-two patients with skeletal lesions were examined with a Picker MR imager (0.15-T resistive magnet). Twenty-five patients had primary malignancies, seven had benign bone neoplasms, 15 had skeletal metastases, and five had neoplasm simulators. Forty-five patients had CT scans available for comparison. For demonstrating the extent of tumor in marrow, MR was superior to CT in 33% of cases, about equal to CT in 64%, and inferior to CT in 2%. For delineating the extent of tumor in soft tissue, MR was superior to CT in 38% of cases and about equal to CT in 62%. CT was superior in all cases for demonstrating calcific deposits and pathologic fractures. In four patients with metal prostheses or surgical clips, MR was superior to CT in documenting recurrent tumor because of artifactual degradation of the CT image. Direct sagittal and coronal images from MR permit accurate assessment of the relationship of tumor to adjacent normal structures, including the physis, joints, and neurovascular structures. MR is useful in the evaluation of bone tumors: it is of greatest value in evaluations of the peripheral skeleton, the medullary canal, soft tissues, and postoperative tumor recurrence. With a 0.15-T magnet, MR is less useful in the evaluation of the axial skeleton and cortical bone.
Limb salvage in primary malignant bone tumors.
Advances in adjuvant chemotherapy and improvements in techniques of oncologic reconstruction have stimulated renewed interest in limb saving operation for malignant bone tumors. Between 1970 and 1981, 160 patients underwent local resection for malignant osseous lesions at the Mayo Clinic. This included 102 patients with chondrosarcoma, 44 with osteosarcoma, and 14 with fibrosarcoma. Ninety-three of the lesions were stage I and 67 were stage II. The overall local recurrence rate was 11.8%. The reconstructive procedures were effective in providing adequate functional restoration. Limb sparing operation is a valid viable option in carefully selected patients with malignant bone tumors. A continued search for effective adjuvant treatment programs is necessary.
Modular prosthetic system for segmental bone and joint replacement after tumor resection.
The increased interest in limb saving resection for malignant bone tumors emphasizes the need for continued research and development to improve techniques of oncological reconstruction. The bioengineer plays an important role on the limb salvage team. At the present time, custom joint implants are opening up new horizons in rehabilitation of patients following resection of bone tumors. In the future, modular prosthetic systems such as the system described will eliminate the need for individual, customized manufacture of prostheses and will make these oncological reconstructive techniques more available.
Missile wounds of the extremities: a current concepts review.
Explore the source record for details and available documents.
Vascular lesions of bone.
Explore the source record for details and available documents.