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R P Veth

Publications and source records attributed to R P Veth.

At least 55 records · Page 3Linked to original sources
PubMed1997

Monitoring during cryosurgery of bone tumors.

BACKGROUND: Cryosurgery is used in orthopaedic oncology as adjuvant treatment after intralesional excision of bone tumors to induce cell death at and beyond the surgical margin. Monitoring freeze/thaw cycles during cryosurgery is beneficial in controlling a cryosurgical procedure and in preventing an unwarranted local extent of the freeze. METHOD: We conducted a study of 15 cryosurgical procedures with the use of a protocolized temperature measuring system wit peroperative graphic visualization. RESULTS: Using a liquid nitrogen spray, intralesional temperatures of -150 degrees C were achieved, which are, according to the literature, associated with cell death. Extralesional temperature measurements showed no sub-zero temperatures of surrounding important tissues. CONCLUSIONS: Temperature recordings in and outside the lesion during cryosurgery in orthopaedic oncology are of importance to monitor the freeze/thaw cycles and are helpful in facilitating an effective cryosurgical procedure and in controlling the extent of the freeze, avoiding local complications.

Adolescent↗
PubMed1997

Isolation of osteosarcoma-associated amplified DNA sequences using representational difference analysis.

Comparative genomic hybridization analysis of a primary osteosarcoma and its metastasis revealed two regions of DNA amplification, one at 17p11.2-12 and one at 19q12-13. Subsequent representational difference analysis of the primary tumor resulted in the isolation of two distinct tumor-amplified DNA fragments originating from chromosome 19. A YAC clone corresponding to one of the two isolated DNA fragments was used for fluorescence in situ hybridization on normal human lymphocyte metaphases and tumor-derived nuclei. This resulted in the localization of this YAC to 19q12-13.1 and confirmed the amplification status of the isolated fragment in the tumors. The availability of such RDA-isolated sequences may be instrumental in the search for genes relevant for tumor development.

Adolescent↗
PubMed1997

Meniscal tissue regeneration in porous 50/50 copoly(L-lactide/epsilon-caprolactone) implants.

Porous materials of a high-molecular-weight 50/50 copolymer of L-lactide and epsilon-caprolactone with different compression moduli were used for meniscal repair. In contrast to the previously used 4,4'-diphenylmethane and 1,4-trans-cyclohexane diisocyanates containing polyurethanes, degradation products of the copolymer are non-toxic. Two series of porous materials with compression moduli of 40 and 100 kPa respectively were implanted in the knees of dogs using a new, less traumatizing suturing technique. A porous aliphatic polyurethane series with compression modulus of 150 kPa was implanted for comparison. Adhesion of the implant to meniscal tissue was found to be essential for healing of the longitudinal lesion. Copolymer implants showed better adhesion, probably due to the higher degradation rate of the copolymer. Fibrocartilage formation was found to be affected by the compression modulus of the implant. Implants with a modulus of 40 kPa did not show ingrowth of fibrocartilage, whereas implants with compression moduli of 100 and 150 kPa yielded 50-70 and 80-100% fibrocartilage respectively. During degradation the copolymer phase separated into a crystalline phase containing mainly L-lactide and an amorphous phase containing mainly epsilon-caprolactone. The copolymer degraded through bulk degradation.

Animals↗
PubMed1997

External and internal hemipelvectomy for sarcomas of the pelvic girdle: consequences of limb-salvage treatment.

The outcome of different limb-saving treatment modalities for pelvic girdle sarcoma is controversial. The oncological and functional results after 11 external and 10 internal hemipelvectomies and the consequences of limb-salvage treatment were studied in 21 consecutive patients with primary bone (19 patients) or soft tissue sarcoma (two patients) of the pelvic girdle. Following external hemipelvectomy, 10 patients (91%) died after a median follow-up of 1.6 years (range: 0.3-7.1). Isolated local recurrences occurred in three patients (27%), with concomitant distant failure in one (9%), while isolated distant failure occurred in six patients (55%). The rate of flap necrosis and wound infection following external hemipelvectomy were both 25%. Following internal hemipelvectomy, nine patients (90%) were alive without evidence of disease after a median follow-up of 6.6 years (range: 2.3-16.0). Concomitant local and distant failures were found in one patient (10%). Reconstruction-related complications necessitated revisional procedures in five of seven patients (72%), leading to external hemipelvectomy in one. Patients with a locally advanced pelvic girdle sarcoma who are unable to undergo an internal hemipelvectomy have a worse prognosis than patients who undergo an internal hemipelvectomy. An internal hemipelvectomy is not attended by an increased risk of local failure, but is by long-term local complications, requiring extensive surgical procedures.

Adolescent↗
PubMed1997

Aneurysmal bone cysts treated by curettage, cryotherapy and bone grafting.

We treated 26 patients with 27 aneurysmal bone cysts by curettage and cryotherapy and evaluated local tumour control, complications and functional outcome. The mean follow-up time was 47 months (19 to 154). There was local recurrence in one patient. Two patients developed deep wound infections and one had a postoperative fracture. We compared our results with previous reports in which several different methods of treatment had been used and concluded that curettage with adjuvant cryotherapy had similar results to those of marginal resection, and that no major bony reconstruction was required. We recommend the use of cryotherapy as an adjuvant to the surgical treatment of aneurysmal bone cysts. It provides local tumour control. Combination with bone grafting achieved consolidation of the lesion in all our patients.

Adolescent↗
PubMed1997

Triple osteotomy of the pelvis for acetabular dysplasia: results at 8 to 15 years.

Reorientation of the acetabulum may be required in adolescents and young adults with developmental dysplasia of the hip. We have carried out a retrospective review of 51 hips after triple osteotomy with an average follow-up of ten years (8 to 15). Forty-eight hips (94%) were available for review and of these 39 (81%) were improved compared with before operation, 29 (60%) scoring good or excellent. Radiographic assessment showed improvement of the average centre-edge angle by 19 degrees, the acetabular index by 12 degrees and the anterior centre-edge angle by 26 degrees. The degree of osteoarthritis progressed by one grade in ten hips (21%) over a period of ten years. The satisfactory long-term clinical and radiographic results have encouraged us to continue this treatment for symptomatic acetabular dysplasia in these patients.

Acetabulum↗
PubMed1997

First clinical experience with a noninvasively extendable endoprosthesis: a limb-saving procedure in children suffering from a malignant bone tumor.

A modular endoprosthetic system that can be extended noninvasively has been applied for the first time in a growing child who underwent a tumor resection in his leg. The main goal of the study was to test the extendable mechanism that noninvasively corrects leg length differences caused by growth disturbances of the affected leg. The use of this endoprosthetic system resulted in good restoration of function. Six extensions were performed resulting in 19.5 mm of prosthetic growth. Unfortunately, an ingrown toenail caused infection of the endoprosthesis, and the infection necessitated extirpation of the prosthesis 15 months postoperatively. Two months later the patient died of acute leukemia. Analysis of the endoprosthesis revealed some manufacturing shortcomings, none of which impaired the function of the endoprosthesis.

Adolescent↗
PubMed1996

Meniscal replacement using a porous polymer prosthesis: a preliminary study in the dog.

A porous polyurethane prosthesis was used to replace the lateral meniscus in the dog. After an initial ingrowth of fibrous tissue, the prostheses became filled with tissue strongly resembling normal meniscal fibrocartilage. Although less severe than seen after total meniscectomy, cartilage degeneration was frequent, possibly because tissue ingrowth in the prostheses occurred too slowly. Porous polymers can be useful for replacement of the meniscus, provided that chemical and physical properties are optimized.

Animals↗
PubMed1996

Use of porous polyurethanes for meniscal reconstruction and meniscal prostheses.

In the past, porous materials made of an aromatic polyurethane (PU) were successfully used to meniscal reconstruction in dogs. Since aromatic PUs yield very toxic fragments upon degradation, a linear PU was synthesized by curing a poly(epsilon-caprolactone) and 1,4-trans-cyclohexane diisocyanate based prepolymer with cyclohexanedimethanol. Porous materials of this polymer were also implanted for meniscal reconstruction. The results were comparable with the most successful implant series so far. Additionally, a porous meniscal prosthesis was developed to replace a total meniscus. Due to the very high shear stresses to which the prosthesis would be exposed, the stress hysteresis phenomenon linear PUs are known to exhibit could be of great consequence. Therefore an aliphatic PU network, synthesized by cross-linking poly(epsilon-caprolactone) and 1,4-trans-cyclohexane diisocyanate with glycerol, was used. Dislocation caused by tearing out of the sutures was found to be a problem because the tear resistance of the material was relatively low. In this study the tearing problem has been partly circumvented by using a complex suturing technique. Meniscal prostheses turned out to induce fibrocartilage upon implantation, and degeneration of articular cartilage was less severe than after meniscectomy.

Animals↗
PubMed1996

Meniscal repair by fibrocartilage in the dog: characterization of the repair tissue and the role of vascularity.

Lesions in the avascular part of 20 canine menisci were repaired by implantation of a porous polyurethane. Seven menisci were not repaired and served as controls. The repair tissue was characterized by biochemical and immunological analysis. The role of vascularity in healing was studied by perfusion of menisci with Indian ink. Histologically, repair tissue inside the implants initially consisted of fibrous tissue containing type I collagen. After 2 months, fibrocartilaginous tissue developed inside the implants, whereas control defects only showed repair with fibrous tissue. Both type I and type II collagen, the two major collagen types of normal meniscal fibrocartilage, could be detected in this newly formed fibrocartilage. The implant guided vascular tissue from the periphery towards the lesion resulting in healing of the tear. After fibrocartilage had formed, vascularity decreased and was completely absent in mature fibrocartilage. Control defects remained filled with vascular connective tissue. Two-thirds of the longitudinal lesions were found to be healed partially or completely. It is concluded that implantation of a porous polymer does enhance vascularity sufficiently to result in healing of meniscal lesions extending into the avascular part. Healing takes place by repair tissue strongly resembling normal meniscal fibrocartilage.

Animals↗
PubMed1995

[Chronic recurrent multifocal osteomyelitis].

In a 9-year-old girl chronic recurrent multifocal osteomyelitis was diagnosed, a rare disease mostly affecting children of which the aetiology remains obscure. It is usually diagnosed around the age of II years. The patient suffers from exacerbations and remissions for an average of 2.9 years. Awareness and recognition of the disease is of importance to avoid unnecessary diagnostic procedures and treatment. The prognosis is good.

Child↗
PubMed1995

Venous gas embolism during cryosurgery for bone tumors.

Cryosurgery using liquid nitrogen is a method for treating benign- and low-malignant skeletal tumors. The advantage of preserving the supportive function of bone should be compared to the risk for its complications; postoperative fracture is well known, but less so the occurrence of intraoperative venous gas embolism. This paper describes 17 patients: 2 patients who had serious hemodynamic complications during cryosurgery and a study of 15 patients in whom end-tidal N2 tension was measured in an attempt to investigate the clinical incidence of venous gas embolism during cryosurgery. In the 15 cases analyzed, we did not detect any exhaled N2 during cryosurgery.

Adolescent↗
PubMed1995

Ewing's sarcoma of bone: oncologic and functional results.

This paper describes 29 patients with Ewing's sarcoma of bone treated between 1975 and 1990 at the University of Nijmegen Hospital, Nijmegen, The Netherlands. Osteomyelitis was the primary diagnosis in 24%. Treatment consisted of chemotherapy in combination with surgery and/or radiotherapy. Nine patients received radiotherapy only; five of them died of disease. Five patients underwent an intralesional excision; four of them died of disease. Twelve patients underwent a wide excision; there is no evidence of disease in any of them. Three patients underwent a radical disarticulation; all died of disease. The disease-free survival at 1.5 years was 66%. This figure at 5 years was 55%. After wide excision and reconstruction in tumors of expendable, femoral or radial bones good functional results were obtained in all cases.

Adolescent↗
PubMed1995

Aneurysmal bone cyst. Long-term results and functional evaluation.

A study was performed on 13 patients with 16 primary aneurysmal bone cysts (ABC) to assess long-term results and functional outcome. The average age at diagnosis was 19.8 years. The anatomical sites were femur (4), tibia (5), humerus (2), fibula (2) and other (3). Four ABC's required no treatment. One patient underwent radiotherapy for an ABC of the spine. Eleven ABC's were treated surgically, mostly by intracapsular resection and bone grafting. Three patients had a total of 6 recurrences, which needed further treatment. At the time of follow-up (average period: 102 months), the average functional evaluation rate of 13 patients was 96%. These functional results were graded as excellent in 9 patients and good in 4.

Adolescent↗
PubMed1994

[Primary treatment of unstable pertrochanteric femoral fractures using a head-neck prosthesis in elderly patients].

OBJECTIVE: Evaluation of the treatment of unstable pertrochanteric femoral fractures with a femoral head prosthesis in older patients. DESIGN: Descriptive. SETTING: University Hospital Nijmegen, the Netherlands. METHOD: From January 1988 through December 1992, 15 patients with 15 unstable pertrochanteric femoral fractures were treated with a femoral head prosthesis and additional wiring of the trochanter. The group consisted of 11 women and 4 men with a mean age of 86 years. Two operations were secondary treatments after broken angled-plate fixation. The other 13 were primary treatments. RESULTS: A stable fixation allowing weight-bearing was achieved in all cases. The operations were accompanied by high morbidity and mortality rates: 4 patients died within 3 months after surgery. One dislocation of the prosthesis occurred. Twelve fractures consolidated, pseudarthrosis of the greater trochanter occurred twice. Five patients regained their preoperative walking ability. CONCLUSION: Femoral head prosthesis with additional wiring is an alternative with few mechanical complications in the treatment of unstable pertrochanteric femoral fractures.

Aged↗
PubMed1994

Tumor progression in a giant cell type malignant fibrous histiocytoma of bone: clinical, radiologic, histologic, and cytogenetic evidence.

A malignant fibrous histiocytoma (MFH) of bone arising in the fibula of a 21-year-old woman is described. Clinical, radiologic, and histologic findings demonstrated rapid tumor progression. Chromosomal analysis of the biopsy specimen showed great karyotypic heterogeneity, whereas the resection specimen four weeks later displayed a rather homogeneous karyotype. Both revealed a clonal t(14;22)(q11;p12). Several other clonal and non-clonal chromosomal aberrations were observed. Some of these were previously described in giant cell tumor of bone (GCTB) and may correlate with aggressive behavior, e.g., aberrations involving 8p11, 19q13, and 20q13. The change from karyotypic heterogeneity to relative homogeneity may be related to tumor progression. The chromosomal findings further suggest that the giant cell type of MFH of bone may be related to malignant GCTB.

Adult↗