Biomedical subjects

V L Fornasier

Publications and source records attributed to V L Fornasier.

At least 19 recordsLinked to original sources

PubMed1999

Cartilaginous metaplasia in the capsule of a Dacron-backed silicone gel breast prosthesis.

Capsular metaplastic changes described as "synovial metaplasia" have been reported in association with silicone gel breast prostheses. Initially this finding was thought to be more common with textured implants. Recent studies have shown no relation between implant shell type (textured vs. smooth). The incidence of this metaplasia has been shown to decrease with the age of the implant, suggesting that it is a transitional finding in capsular maturation. The metaplastic cells in the synovial metaplasia may have secretory characteristics, but the exact etiology and function of the metaplasia are not yet fully understood. Experimentally, a similar connective tissue reaction has been induced by repeated injections of air to produce the so-called "air pouch." The current study describes cartilaginous metaplasia in the capsule surrounding a silicone-filled, Cronin-type, Dacron-backed breast prosthesis. At 26 years after bilateral breast augmentation, this patient presented with breast pain and firmness. During surgical removal the implants were intact but the capsules were densely hyalinized, irregularly calcified, and on one side there was cartilaginous metaplasia within the connective tissue of the capsule. This had occurred independently of calcification. This was believed to be an unusual tissue response. Review of the English literature failed to identify a comparable case.

Breast↗

PubMed1998

Radiation-induced tibial sarcoma in a treated case of hind foot angiomatosis.

Hemangiomatosis with osteolysis, osteosclerosis and loss of bony definition is an uncommon disease entity. Many forms of treatment have been used, varying almost from case to case. The use of radiation therapy has proved successful in the control of the disease process in reported cases. The current case of hind foot hemangiomatosis went on to develop sarcoma 17 years later in the uninvolved tibia at the margin of the radiation field, which proved to be fatal to the patient. Treatment by radiotherapy had permitted normal function for 15 years. This case highlights the difficulties of management of skeletal angiomatosis based on anatomic location and emphasizes the need for judicious planning and selection of the mode of delivery of radiotherapy.

Adult↗

PubMed1996

Histomorphological reaction of bone to different concentrations of phagocytosable particles of high-density polyethylene and Ti-6Al-4V alloy in vivo.

Wear debris has been implicated in the pathogenesis of loosening and osteolysis of total joint replacements by stimulating a foreign body and chronic inflammatory reaction capable of bone resorption. Whether increasing concentrations of wear particles have an adverse biological effect on bone has not been elucidated. We performed a histomorphological and semi-quantitative morphometric analysis of the reaction of bone to different concentrations of phagocytosable particles of high-density polyethylene (HDPE) and titanium 6-aluminium 4-vanadium alloy (Ti-6Al-4V) implanted in the rabbit tibia. The Ti-6Al-4V particles had a diameter of 4.0 +/- 4.4 microns (mean +/- SD); the HDPE particles averaged 4.7 +/- 2.1 microns. Suspensions of 10(6)-10(9) particles per ml were mixed in saline, sterilized, and introduced through a drill hole into the proximal tibia of 30 mature female rabbits. Controls included drilled, but non-implantable limbs. The animals were killed at 16 weeks and histological sections were made of the implant area. Histomorphological assessment was carried out using an interactive image analysis system. The parameters assessed included the presence of histiocytes, foreign body giant cells and inflammatory cells, the location and number of particles, the presence of haematopoeitic elements, fat or necrosis of the marrow, whether healing of the cortical window had taken place, and whether there was evidence of formation or resorption of bone by the periosteum, cortex and marrow. A semi-quantitative rating system was employed. Phagocytosable particles of Ti-6Al-4V and HDPE, in concentrations of 10(6)-10(9) particles per ml, evoked a histiocytic reaction without extensive fibrosis, necrosis or granuloma formation. This reaction occurred without disturbing the normal repair processes of bone formation and resorption to the surgical insult. A clear dose-response effect on the histological parameters assessed in this study was not noted. Using the present model, by 16 weeks, a similar "one time' particle load could be accommodated. The ongoing generation of particulate debris over a more extended period of time might be necessary before the remodelling processes of bone would be disturbed.

Alloys↗

PubMed1996

The prognostic significance of histomorphometry and immunohistochemistry in giant cell tumors of bone.

Eighty-two cases of giant cell tumor (GCT) were reviewed. Hematoxylin-eosin-and hematoxylin, phloxine, saffron, and alcian green-stained sections (82 cases) were examined for mitotic rate, the number of giant cells, and the pleomorphism of the stromal cells. In 29 cases, the tumor was stained for CD68, alpha 1-antichymotrypsin (AIACT), S100 protein, Muramidase, and von Willebrand factor (factor VIII). The staining properties of mononuclear and multinucleated giant cells were compared. Morphometric analysis was performed on 14 cases with a LECO 2001 computer-assisted image analyzer (LECO Instruments Ltd, Mississauga, Ontario, Canada) and included absolute cell count, nuclear area, perimeter, roughness, roundness, and aspect and nuclear versus cytoplasmic ratios, measured both in the stromal cells and giant cells. The cases were divided into four groups: (1) cases with metastasis, (2) cases with recurrence, (3) cases with both metastasis and recurrence, and (4) cases with neither metastasis nor recurrence. Immunohistochemistry revealed a stronger AIACT than muramidase positivity in general. The staining was stronger in stromal cells than in giant cells. Giant cells in all tumors were positive for CD68. Stromal cells showed weaker positivity for the same stain. The number of asymmetrical mitotic figures was significantly greater in group 3 than in group 4 (P < .05). Morphometric assessment has identified a statistically significant difference in the aspect ratio and the roundness of the nuclei between these two groups. The other parameters did not differ significantly. In this article, the significance of these findings in prognostication and the histogenesis of the giant cell tumor are discussed. Their clinical applicability is yet to be determined.

Adolescent↗

PubMed1996

Operative treatment of subcalcaneal pain.

Twenty of 21 consecutive patients (21 heels) with subcalcaneal pain retractory to conservative treatment managed by resection of the proximal attachment of the plantar fascia and the heel spur, if present, were reviewed retrospectively. The results, at a mean followup of 40 months (range, 12-102 months), using a 100 point scoring system, rated excellent in 8 patients, good in 10, fair in 1, and poor in 1 (90% satisfactory outcome). Time to maximal improvement often was prolonged, yet once reached was maintained over time. The only complication encountered was 1 superficial wound infection. Radiographically it was noted that, despite complete excision, subcalcaneal exostoses often reformed and the fascial transection never did precipitate collapse of the longitudinal arch of the foot. A combination of mucoid and fibrinoid degeneration of the plantar fascia, an acceleration of an age related process, was the principal histopathologic finding. It was concluded that the subcalcaneal pain unresponsive to conservative modalities can be treated effectively by the index procedure. The radiographic and histologic findings of this study suggest that changes within the fascia, rather than the spur, are primarily responsible for the pathogenesis of the syndrome.

Adult↗

PubMed1995

Homing of 51Cr-labeled human peripheral lymphocytes to Graves' thyroid tissue xenografted into SCID mice.

We have recently described a NUDE/SCID mouse model that has been useful for the study of human thyroid autoimmunity in in vivo conditions. The reappearance of lymphocytic infiltration in Graves' thyroid tissue and a humoral response in SCID mice (rexenografted with normalized thyroid tissues from NUDE mice) was detected only if autologous Graves' human peripheral lymphocytes (PBMC) were engrafted into the same animals. Therefore it was presumed that some autoreactive PBMC directed themselves to the thyroid. However, there was previously no direct evidence regarding the trafficking of the engrafted PBMC to the target tissue. To elucidate this point we have studied the migration of 51Cr-labeled PBMC in SCID mice. Human thyroid tissue from six Graves' disease (GD) patients and six patients with nontoxic nodular goiter were initially xenografted into NUDE mice for 8 weeks. The same tissues were retrieved and rexenografted into several "virgin" SCID mice, i.e., no previous xenografts. Autologous PBMC were isolated from blood of the same patients obtained at the time of the tissue rexenograftment and labeled with radioactive 51Cr. Twenty million labeled PBMC were engrafted into each SCID mouse. The distribution of labeled lymphocytes into mouse organs and trafficking into Graves' and normal xenografts was measured. A significant amount of radioactivity in Graves' xenografts was detected after 1 week with the peak of radioactivity at 2-3 weeks. This radioactivity was significantly higher than radioactivity in surrounding tissues (skin, muscle). In contrast, homing of autologous lymphocytes into normal paranodular thyroid tissue was very minimal; the radioactivity of GD thyroid xenografts with engrafted autologous lymphocytes was significantly higher than that of normal tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Local control of soft tissue sarcoma of the extremity: the experience of a multidisciplinary sarcoma group with definitive surgery and radiotherapy.

Data gathered on 62 patients with soft tissue sarcoma of an extremity, treated in entirety by an experienced multidisciplinary sarcoma group, were analysed. With a philosophy of emphasising attainment of histologically negative margins at carefully planned limb sparing surgery, combined with either pre-operative or postoperative radiation therapy, a crude local control rate of 95% (59 of 62 patients) at a minimum of 24 months follow-up was obtained. Of 9 patients with microscopically positive margins after definitive surgery, 8 had undergone maximal resection compatible with preservation of function. One of these 9 failed locally, indicating that radiation therapy is effective in eradicating microscopic disease in this tumour. The excellent local control obtained with limb-sparing surgery in this series justifies early referral of patients with these uncommon cancers to an experienced multidisciplinary unit. 26 patients (42%) failed systemically at a minimum of 24 months follow-up, and 19 (30.6%) died of their disease, confirming the need for effective systemic therapy in soft tissue sarcoma. Tumours greater than 10 cm in diameter had a greater risk of systemic relapse.

Adolescent↗

PubMed1994

Wound-healing complications after soft-tissue sarcoma surgery.

One-hundred and eighty patients undergoing limb-salvage surgery for soft-tissue sarcoma from 1986 to 1991 were assessed retrospectively for risk factors associated with major wound-healing complications. Twenty-three of 137 patients (16 percent) treated with primary direct wound closure sustained complications. In univariate analysis, the cross-sectional area of tumor resection, the use of preoperative irradiation, the width of the skin excision, a history of smoking, and a history of diabetes and/or vascular disease were associated with wound failure. Multivariate analysis revealed that preoperative irradiation (p = 0.04) and resection diameter (p = 0.017) accounted for the risk of complications. Eighteen additional patients were treated empirically with distant vascularized tissue transfer following preoperative irradiation because of concerns regarding potential wound complications. The lower complication rate in this group suggested that vascularized tissue transfer may be beneficial in lowering wound complication rates.

Adolescent↗

PubMed1994

Fixation with biodegradable devices of acetabular components in a canine model.

Cementless total hip arthroplasty was performed in 13 dogs. The acetabular component was anchored with two biodegradable devices (polylactic acid) in seven dogs and with two titanium screws in six dogs. At 14 weeks, histomorphometric determinations of bony ingrowth into the porous coating of the acetabular weight bearing dome was 54.4% when fixed with the biodegradable devices and 58.9% when fixed with the titanium screws (no statistically significant difference; p = 0.556). At the sites of fixation, less bony ingrowth occurred with the biodegradable devices. The use of biodegradable devices in total hip arthroplasty should overcome the potential metal corrosion of titanium screws that can lead to polyethylene wear.

Animals↗

PubMed1993

Histological reaction to titanium alloy and hydroxyapatite particles in the rabbit tibia.

The interfacial membrane harvested from failed joint replacements contains particulate debris from the materials used for the implant. To define the tissue response to particulate titanium alloy and hydroxyapatite (HA) alone, 16 mature New Zealand white rabbits were divided into 2 groups of 8 rabbits. Using sterile technique, a drill hole was placed anteromedially in the tibia, 1 cm distal to the knee joint bilaterally. The marrow was scooped out and 0.25 mg of either titanium alloy particles or HA particles were inserted in the right tibia. The titanium alloy particles had a diameter averaging 4.0 +/- 4.4 microns (mean +/- standard deviation) and an aspect ratio (the ratio of the maximum length divided by the maximum width) of 1.84. The HA particles had a diameter of 4.4 +/- 3.3 microns and an aspect ratio of 1.76. The left leg was prepared in a similar fashion, but no biomaterial was implanted. The animals were killed after 16 wk. The harvested tibiae were processed with decalcification and the plastic-embedded sections were subjected to histomorphological analysis. Black titanium alloy particles were present within the bone marrow fat between haematopoietic cells, and within scattered macrophages. The surrounding bone appeared to be unaffected. Within the spongiosa, the HA particles were surrounded by small numbers of mononuclear histiocytes or encased within a shell of new appositional bone. Where HA deposits were exposed to the endosteal aspect of bone, there was scalloping of the surface of the HA in a pattern suggestive of resorption or dissolution of the HA particles.(ABSTRACT TRUNCATED AT 250 WORDS)

Alloys↗

PubMed1993

Radiological and histological study of aseptic loosening using a cemented tibial hemiarthroplasty in the rabbit knee.

Fourteen mature New Zealand white female rabbits had a unilateral cemented, stemmed, titanium, condylar-type tibial hemiarthroplasty, using an anteromedial arthrotomy of the right knee. The articular cartilage and minimal bone were resected. There were two prosthetic groups of seven animals each: a well-fixed, non-loose group and a loose group. In the non-loose group, the implant was inserted into the cement bed and axially compressed until the PMMA had cured. In the loose group, the same volume of cement was allowed to cure on the implant ex vivo; the prosthesis was then implanted to ensure that it was loose fitting. Radiographs were performed at zero and 3 months and graded for new lucent lines. Histological analysis was performed using undecalcified coronal sections, surface stained with toluidine blue with the prosthesis in situ, and the cement mantle preserved. Back-scattered electron microscopy was also performed. The mean cumulative grading of new lucent lines was 0.3 +/- 0.1 for the non-loose group and 2.2 +/- 0.4 for the loose group (P < 0.005). Non-loose prostheses were surrounded by a thin fibrous membrane or bone. Loose prostheses were surrounded by a thicker, fibrous tissue layer, containing histiocytes and giant cells which were more prevalent around cement particles, especially near the prosthetic tip. These findings parallel the histology found at cemented prosthetic interfaces in humans. The results of this study suggest that the fibrohistiocytic membrane commonly found around loose cemented implants may be the result of, rather than the cause of, the loosening process.

Animals↗

PubMed1992

Osteoid osteoma of the elbow: a report of six cases.

We report six cases of osteoid osteoma of the elbow. Elbow pain was the presenting complaint in all of these young adult patients. A variety of diagnoses were entertained, and four patients underwent surgical procedures that were not helpful. Although an abnormality was identified on plain x-ray films, tomograms and a bone scan were helpful in isolating the lesion. A CT scan proved valuable in two cases. Complete en bloc excision relieved pain and improved function in each case.

Adolescent↗

PubMed1991

Wound healing complications in soft tissue sarcoma management: comparison of three treatment protocols.

A prospective, nonrandomized comparison of three treatment protocols was undertaken in 45 patients with soft tissue sarcoma designated preoperatively as being at high risk of wound healing complications. All patients underwent complete resection of the gross tumour mass (5 with positive and 40 with negative microscopic margins). Fourteen patients received postoperative adjuvant irradiation (group I), 16 preoperative irradiation (group II), and 15 preoperative irradiation and vascularized tissue transfer to the surgical bed after resection (group III). Major wound healing complications (defined as complications requiring at least 1 further surgical procedure) were lower in group III patients (chi-square = 5.57, P less than 0.03), as was the mean postoperative hospital stay (P less than 0.02, analysis of variance), and the mean number of secondary surgical procedures. Multivariate analysis showed that the only variable influencing length of stay was the use of tissue transfer. Careful intraoperative assessment of the adequacy of resection is essential prior to performing vascularized tissue transfer to ensure that tumour contamination of the donor site is avoided. Since this study is a nonrandomized clinical trial using sequential distribution of patients to the treatment groups, the data should be considered as preliminary, rather than definitive, evidence of the efficacy of vascularized tissue transfer.

Combined Modality Therapy↗

PubMed1991

Functional outcome in patients treated with surgery and irradiation for soft tissue tumours.

One hundred five consecutive patients underwent surgical resection and adjuvant irradiation in treatment of soft tissue sarcoma or aggressive fibromatosis. All patients were entered in a prospective study evaluating functional outcome and 88 patients were examined at 12 months following surgery. Outcome was characterized using the Enneking system as well as documenting employment/recreational status and limb edema. Sixty-eight of 88 patients had functional scores of 21 or better (out of a possible total of 35). Forty-four patients were serially evaluated at 12 and 24 months and there was no difference in their outcome at the 2 time points. Univariate analysis demonstrated that large tumour size, postoperative complications, and neural sacrifice were associated with poor functional outcome.

Adolescent↗

PubMed1991

Quantitative comparison of the histological effects of particulate polymethylmethacrylate versus polyethylene in the rabbit tibia.

Fourteen mature female New Zealand White rabbits underwent implantation of Simplex polymethylmethacrylate (PMMA) powder or particulate (average 67 microns) ultrahigh-molecular-weight polyethylene (UHMWPE) through a drill hole in the proximal right tibia. The left tibia functioned as a prepared but nonimplanted control. Animals were killed after 16 weeks. Histological examination of the bone-implant interface in the particulate PMMA group disclosed a florid foreign-body reaction with the presence of giant cells and histiocytes. The particulate UHMWPE group demonstrated positively birefringent UHMWPE fragments, rimmed by foreign-body giant cells and histiocytes, embedded in a loose connective tissue stroma. UHMWPE interfaces were thicker and contained more histiocytes and fibrocytes; PMMA interfaces contained more marrow cells and lymphocytes. This study underscores the importance of biomaterial debris in the process of aseptic loosening of cemented joint arthroplasties.

Animals↗

PubMed1991

Preoperative and postoperative irradiation of soft tissue sarcomas: effect of radiation field size.

For the treatment of soft tissue sarcomas it has frequently been staged but not quantitatively demonstrated, that the volume irradiated is smaller when irradiation is given preoperatively as compared to postoperatively. In this study the field size used for preoperative irradiation was compared with that necessary in the same patient had the radiation been given postoperatively. Twenty-six patients with soft tissue sarcomas of the extremity, groin, and shoulder girdle who had received preoperative irradiation were resimulated following surgery to determine the size of the postoperative field. The simulation was performed by a physician not involved in the preoperative treatment planning. Preoperatively a radial margin of 5 cm around the tumor was used for low and intermediate grade and 7 cm for high grade sarcomas. Postoperatively the same margins were used but around the surgical field. Twelve patients underwent a wide resection and 14 patients a resection followed by vascularized tissue transfer to the surgical bed. The median follow-up was 22 months (range 13-46). No local recurrences and two cases of distant metastasis were observed. Independently of surgical procedure and tumor grade, the size of the preoperative radiation field and number of joints included in the field were significantly smaller than that of postoperative radiation (p less than 0.001). In two patients preoperatively and four patients postoperatively, the radiation field involved the whole circumference of the limb. Provided that equivalent radiation time-dose-fraction parameters are used and that the complication rate is proportional to the radiation field size, late complications may be less after preoperative irradiation than after post-operative irradiation.

Adolescent↗

PubMed1991

Mechanical overload of a single compartment induces early degenerative changes in the rabbit knee: a preliminary study.

The purpose of this experiment was to determine whether mechanical overload of a single compartment of the knee in rabbits via proximal tibial osteotomy could produce early changes consistent with degenerative arthritis. Ten New Zealand white female rabbits were allocated into two groups. Group 1 (five animals) underwent a right 20 degrees valgus proximal tibial osteotomy to overload the lateral compartment of the knee. Group 2 (five animals) underwent a tibial osteotomy without malalignment (sham controls). The osteotomies were stabilized with a mini AO/ASIF plate and screws, allowing early mobilization. The left leg in each animal was left intact and served as a control. Animals were sacrificed after 3 months. Histological grading of the cartilage was performed according to Mankin et al. The mean histological gradings for the right minus the left knee were the same for the lateral and medial compartments in the 0 degrees sham osteotomy group. However, the mean histological grading of the "overloaded" lateral compartment was 2.4 times greater than the medial compartment in the 20 degrees valgus osteotomy group. These findings suggest that histological evidence of degenerative changes can be surgically induced in the rabbit knee by creating a biomechanical overload of one compartment.

Animals↗

PubMed1991

Response of the articular cartilage to weight-bearing: comparison of hemiarthroplasty with ceramic and cobalt-chromium head in dogs.

The advantages of the use of ceramic in prosthetics are well-known, especially the fact that the coefficient of friction is significantly lower at the bone-ceramic interface than at the bone-metal interface. For this reason, ceramic is used for the cephalic component of the hemiarthroplasty. The advantages of ceramic, however, are purely theoretical, and have never been scientifically proven. The aim of our study, conducted on 20 dogs, was to observe the long-term effects of femoral prosthesis with a ceramic or cobalt-chromium cephalic component upon the acetabular cartilage. Our research was conducted on homogeneous groups of dogs under similar conditions. At 8 months, the results showed evident cartilage damage that was equal in both groups. We therefore conclude that as far as everyday wear neither material is favored over the other.

Acetabulum↗