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Biomedical subjects

A Toni

Publications and source records attributed to A Toni.

At least 109 records · Page 6Linked to original sources
PubMed1993

A software simulation of tibial fracture reduction with external fixator.

In modern orthopaedic practice, circular external fixators are frequently preferred to plaster cast for various reasons. The realignment of the two fractured bone segments is usually performed under a continuous fluoroscopy checking which involves a long radiation exposure time for both patients and surgeon. In order to overcome this problem, a computer controlled external fixator is under development. One relevant problem which this project faced in its initial stage was the difficulty to define in geometrical terms the manual reduction trajectory normally adopted by the surgeon. Basically it was a typical problem of empirical knowledge transfer from the surgeon to the engineer. Thus, it was necessary to create a common ground where the two experts could carry out the necessary analyses in order to define an empirical algorithm capable of suggesting a correction trajectory. The problem was solved by developing a simulation program called S.E.R.F. (Simulation Environment of a Robotic Fixator) provided with an extremely powerful graphic output, able to visualize the whole reduction trajectory from any viewpoint in space. The authors suggest the use of this kind of tool every time the techno-clinical information exchange is a critical issue.

Algorithms↗
PubMed1993

The role of surgical therapy in patients with nonmetastatic Ewing's sarcoma of the limbs.

Of 131 patients with primary Ewing's sarcoma (ES) with extremity locations, treated between April 1972 and May 1987, 13 had amputation; 56 had a local resection with 31 (55%) requiring radiation therapy (RT) as an adjuvant to local therapy. Sixty-two of 131 patients (47%) had RT only. Local recurrences were reported in 5% of patients treated with surgery alone, 1% of the group treated with surgery and radiation therapy, 24% of patients treated with radiation therapy alone (46% for cesium-radiation therapy, and 12% with cobalt-radiation therapy).

Adolescent↗
PubMed1992

Microradiographic and histochemical evaluation of mineralization inhibition at the bone-alumina interface.

Microradiographic and histochemical tests were used to examine the behaviour of the bone tissue close to the alumina coating in cementless hip prostheses which were radiologically stable and explanted because of pain. The presence was detected of a decalcification stripe of the bone tissue with a thickness of about 300 microns, parallel to the prosthesis profile and in appearance not influenced by the roughness of the surface. This phenomenon was attributed to the presence of aluminium ions similarly to what happens in osteomalacic osteodystrophy in nephropathic dialysed patients. It was concluded that the phenomenon must be carefully considered because, in the long term, it could cause failure in the alumina coating.

Aluminum↗
PubMed1991

Cellular events in the mechanisms of prosthesis loosening.

The functional restoration of a joint damaged by trauma or disease is obtained by prosthetic surgery. In particular the implantation of hip prostheses is regarded as routine in orthopedic surgery and thorough research has been developed in this field. The prosthetic replacement of the knee and even more so the ankle and elbow occurs less frequently in clinical practice and has been studied less intensively. The results of artifical hip replacement are generally good, both in terms of pain relief and the restoration of satisfactory joint function. Nevertheless, as time passes, a high rate of failures have been recorded due to prosthesis infections, fracture and wearing of the prosthetic components and prosthesis loosening by various causes. The use of ultra-filtered air and laminar flow in operating theatres and antibiotic prophylaxis have dramatically reduced the incidence of infections in total hip arthroplasty. Thanks to the setting up of new stem configurations and the use of superalloys that are highly resistant to fatigue failure, the fracture of the femoral component has been virtually eliminated as a complication of total hip arthroplasty replacements. Loosening is thus the most frequent complication in total hip replacement.

Bone Cements↗
PubMed1990

Ewing's sarcoma of the pelvis.

Two hundred and thirty-nine patients with Ewing's sarcoma were treated at our institution between 1972 and 1987: 42 of these had lesions in the pelvis, 29 were in the wing of the ilium or involved the sacroiliac joint (type I), 5 were periacetabular (type II), and 8 were in the anterior pelvic arch (type III). Radiotherapy alone was used for the primary lesion in 11 cases, adjuvant chemotherapy in 20 and a neoadjuvant protocol in 22. The overall disease-free survival at a mean follow up of 34 months was 19%. There was no difference in survival related to age or the site in the pelvis, none in disease-free survival with adjuvant and neoadjuvant chemotherapy, or in the incidence of local recurrence and metastases in these two groups. Similarly, there was no difference in disease-free survival between operative treatment, with or without radiotherapy, and radiotherapy alone. There was a slight trend towards better local control of the disease in the former group compared to the latter, although this difference was not statistically significant. Our conclusion is that treatment needs to be planned for each individual patient.

Adolescent↗
PubMed1990

Combined therapy of localized Ewing's sarcoma of bone: analysis of results in 100 patients.

From 1979 to 1986, 182 patients with biopsy proven diagnosis of Ewing's sarcoma of bone were observed. One hundred of the 182 patients (72 males, 28 females, median age 15.8 years) with localized disease and no previous treatment were treated with chemotherapy (VCR, ADM, CTX, D-ACT) for 15-18 months. Local treatment was radiotherapy (42 patients), surgery (31 patients), or a combination of both (27 pts). Radiation doses ranged from 45 to 64 Gy given with conventional fractionation. Median follow-up was 51.2 months (24-106). Overall and disease-free survival were, respectively, 58.7 and 42.6%. Resected patients tended to have a better local control (Surgery 93.6%, Surgery + Radiation therapy 92.6%, Radiation therapy 69.1%). Disease-free survival was significantly related to the volume of the primary tumor (bulky: 33.2%, not-bulky: 57.7%), to site (extremities 54.6%, central sites 16.6%, other sites 40.9%), and to local treatment (Radiation therapy 30.3%, Surgery + Radiation therapy 47.9%, Surgery 59.1%). These results are, however, biased because resected patients tended to have smaller tumors in favorable sites.

Adolescent↗
PubMed1989

Neoadjuvant chemotherapy for localized Ewing's sarcoma of the extremities: preliminary results of a protocol which uses surgery (alone or followed by radiotherapy) for local control.

From June 1983 to December 1985, thirty-eight patients with localized Ewing's sarcoma of the extremities were treated with a protocol that consisted of an initial nine week period of polychemotherapy (vincristine, adriamycin and cyclophosphamide) followed by local therapy and additional chemotherapy (vincristine, adriamycin, cyclophosphamide and dactinomycin) for one year. As local treatment all patients were offered surgery; thirty-two accepted and six refused. These six patients were locally treated with radiotherapy alone (50 Gy). In the remaining patients an amputation was performed in one case and a resection in thirty-one. In resected patients when a wide margin was achieved (24 cases) no further local treatment was performed; when it was marginal (5 cases) or intralesional (2 cases) radiotherapy at lower doses (40 Gy) followed. At mean follow-up of thirty-seven months the percentage of continuously disease-free patients was 50% for those treated with radiotherapy, 76% with surgery, and 85% with surgery and radiotherapy. Eight patients developed metastatic disease and two patients had local recurrence and metastases. The local recurrences were seen in one patient locally treated with surgery and in one locally treated with radiotherapy. Nine major local complications were observed: three in patients treated with radiotherapy, five in patients treated with surgery, and one in a patient treated with surgery and radiotherapy. These results indicate that after induction chemotherapy conservative surgery is possible in almost all cases of Ewing's sarcoma of the extremities and that such treatment is better than radiotherapy alone as local therapy.

Adolescent↗
PubMed1989

Long-term results in 144 localized Ewing's sarcoma patients treated with combined therapy.

The results of 144 previously untreated cases of primary Ewing's sarcoma of bone are reported with a minimum follow-up of 5 years. This series was treated between 1972 and 1982 at Istituto Ortopedico Rizzoli with a combined therapy. The local control of the disease consisted of amputation (ten cases), resection followed by radiation therapy (35-45 Gy) (48 cases) and radiation therapy alone (40-60 Gy) (86 cases). Adjuvant chemotherapy, rigorously standardized, was performed according two different protocols: the first (85 cases treated in the period 1972-1978) consisted of vincristine (VCR) Adriamycin (doxorubicin) (ADM), and cyclophosphamide (EDX); the second (59 cases treated in the period 1979-1982) of VCR, ADM, EDX and dactinomycin (DACT). At a follow-up of 5 to 16 years (median, 9), 59 patients (41%) are continuously disease-free (CDF), 81 (56%) developed metastatic disease and/or local recurrence, and four (3%) had a second malignancy. Three factors seem to be correlated to prognosis: the site of the initial lesion (only 23% of the pelvic lesions are represented in the CDF group versus 46% of the other locations); the chemotherapy protocol (32% of the cases in the first protocol are CDF versus 54% in the second); the type of local treatment (60% of the patients treated with amputation or resection plus radiotherapy versus 28% of those treated with radiation therapy alone are CDF). A local recurrence was observed in 24% of the patients (8% in the group locally treated with surgery or surgery plus radiation therapy versus 36% in the group treated with radiation therapy alone). These data suggest that even though adjuvant chemotherapy can improve the long-term results in localized Ewing's sarcoma patients, this disease still represents, in a high percentage of cases, a lethal process whose final prognosis widely depends on the local control of the lesion. Due to the questionable effect of the radiation therapy alone in controlling the primary lesion and its important side effects, the role of surgery in treating Ewing's sarcoma of bone should be extended.

Adolescent↗
PubMed1989

Raman spectroscopy for the study of porous composite alumina coating.

A new acetabular cup prosthesis made of alumina and bioactive glass was studied and evaluated using nondestructive and noninvasive Raman laser spectroscopy. The prosthesis consists of an alumina socket coated with a double layer of alumina beads bonded to the prosthesis with a layer of glass. Raman spectroscopy showed that both the socket and the beads are composed of alpha-Al2O3 (corundum), while the bioactive glass (alkaline and alkaline earth alumosilicate with a small quantity of zirconium oxide) showed this to have an intermediate structure between that of vitreous silica and that of the alkaline and alkaline earth disilicate glasses. The Raman spectra of the contact surfaces between the bioactive glass and the alumina of the assembled prosthesis and of an alumina disk coated with the same glass showed the presence of new bands which may be correlated with a chemical interaction between the components of the prosthesis.

Aluminum↗
PubMed1988

Serum lactate dehydrogenase (LDH) as a tumor marker in Ewing's sarcoma.

The pretreatment serum lactic acid dehydrogenase (LDH) level of 246 patients with Ewing's sarcoma of bone (47 metastatic and 199 localized at presentation) was examined to evaluate the use of LDH as a tumor marker. The percentage of patients with increased serum LDH levels was significantly higher in the metastatic group than in the group of patients with localized disease (83% vs 41%; p less than 0.01). In the latter group the relapse rate after treatment with combined therapy was significantly higher in patients with an elevated serum LDH at admission than in those with normal serum levels (68.2% vs 39.3%; p less than 0.01). After local treatment, in 73 out of 82 patients with an elevated serum LDH at admission the enzyme level normalized whereas in 9 it fell but never reached a normal value. The rate of relapse in these two groups was respectively 64% and 100%. The value of serum LDH at the time of recurrence, determined in 62 patients, was elevated in 50 (80.7%). These data demonstrate that in Ewing's sarcoma of bone pretreatment serum LDH levels have a definitive value in establishing the prognosis and could also be used in evaluating the response to therapy. A persistent elevated value of serum LDH, or an increasing value after a transient normalization, is usually followed by relapse.

Adolescent↗
PubMed1988

Radio-induced sarcomas in survivors of Ewing's sarcoma.

Of 255 cases of Ewing's sarcoma recorded at the Bone Tumor Center of the Rizzoli Orthopaedic Institute, 78 patients (irradiated and with a follow-up of longer than 3 years) were considered "at risk" for the development of a second radio-induced sarcoma (RIS). Three of the 78 patients developed an RIS in the irradiated field. Theoretical and statistical analyses were carried out considering different modalities of local treatment. Statistically, the only significant factor was related to the irradiation dose. Surgical resection seems to prevent RIS.

Adolescent↗
PubMed1988

Multilayered bead ceramic composite coating for hip prostheses: experimental studies and preliminary clinical results.

The clinical use of a new ceramic composite material made up of multilayered alumina beads and adhered to a ceramic surface with a high-temperature-melting bioglass is proposed. The result is a structure characterised by a 27% porosity and an average pore diameter of 400 microns. The actual structure of the parts as well as their interface interaction were determined by Raman laser. The mechanical resistance of the adherence of this coating for the ceramic substratum was good enough to resist the stress to which it was submitted when used for a new model of prosthetic acetabulum. Experiments with rabbits revealed the good biocompatibility of the composite. The osteoproductive activity of the tissue surrounding the implant led to the gradual filling of the porosity with trabecular structures. The preliminary results of the clinical experience which began in November 1985, confirm the good compatibility of the ceramic composite.

Aluminum Oxide↗
PubMed1987

[Therapy of non-metastatic Ewing's sarcoma (pelvis excluded). Results obtained in 48 cases combining local therapy (radiation and/or surgical) and adjuvant chemotherapy with vincristine, adriamycin, dactinomycin and cyclophosphamide].

Combined therapy was used on a consecutive series of 48 patients with extrapelvic Ewing's sarcoma at the Rizzoli Orthopaedic Institute. The adjuvant chemotherapy protocol (VCR, ADM, D-ACT, EDX) was identical in all patients whereas local treatment consisted of amputation, resection and radiation treatment or radiation alone. At a mean follow-up of 58 months (39-78) 30 patients (60%) were free of the disease. This is a significantly higher percentage than that obtained in the same period with adjuvant chemotherapy using only 3 drugs (VCR, ADM, EDX). As far as the type of local treatment is concerned, the percentage of local recurrences and metastases was lower when the primary lesion was treated with surgery or surgery combined with radiotherapy, rather than radiation treatment alone. These suggest that if associated with radiation treatment and chemotherapy, surgery can play an important role that should be considered in the treatment of extrapelvic Ewing's sarcoma.

Antineoplastic Combined Chemotherapy Protocols↗