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Biomedical subjects

V L Fornasier

Publications and source records attributed to V L Fornasier.

At least 19 recordsLinked to original sources
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↗
PubMed1990

The histological effects of the implantation of different sizes of polyethylene particles in the rabbit tibia.

This study examines the histological effects of different sizes of polyethylene particles implanted into the rabbit tibia. Seventeen mature New Zealand white female rabbits were allocated into three groups. Group 1 (5 rabbits) received polyethylene particles averaging approximately 16 microns in diameter, implanted into the right proximal tibia through a drill hole. Group 2 (5 animals) received particles averaging 26 microns, and Group 3 (7 rabbits) received particles averaging 67 microns. The left tibia was drilled but not implanted. Animals were sacrificed after 16 weeks. Histological analysis disclosed decreased hematopoietic activity within the left tibial drill hole. In all groups, the right tibia demonstrated positively birefringent polyethylene particles surrounded by, and within (smaller particles), histiocytes and giant cells in a fibrous tissue stroma. Statistical analysis disclosed more fibrocytes and less marrow cells at the interface of Group 3 (largest particles) compared to Group 1 and 2. Larger polyethylene particles, being less readily phagocytosed, appear to produce more fibrous encapsulation, compared to particles of a smaller size. The histological reaction stimulated by the different sizes of polyethylene particles resembled the membrane surrounding loose joint arthroplasties in humans.

Animals↗
PubMed1990

The effects of bulk versus particulate titanium and cobalt chrome alloy implanted into the rabbit tibia.

Twenty-eight mature New Zealand white female rabbits were allocated into 4 groups of 7 rabbits. Group 1 received a coiled wire of cobalt chrome alloy (Vitallium) (16 gauge x 1 cm). Group 2 received an equal weight of cobalt chrome particles averaging 15.4 microns in diameter. Group 3 received a coiled wire implant of commercially pure (C.P.) titanium (16 gauge x 1 cm). Group 4 received the same weight of C.P. titanium particles averaging 3.8 microns. The implants were placed through a drill hole in the proximal right tibia; the left tibia served as a prepared but nonimplanted control. The animals were killed after 16 weeks and quantitative histology was performed on undecalcified sections of the implant area. Bulk cobalt chrome and titanium implants were surrounded by a thin, incomplete, fibrous tissue layer with decreased numbers of cells. Trabeculae of bone were present within this connective tissue envelope. Fingerlike projections of bone enveloped the implant where it abutted endosteal bone. Clumped and loosely scattered cobalt chrome and titanium particles were surrounded by a minimal amount of fibrous connective tissue. Smaller particles were present within cells. Hematopoietic cells abutted the bulk or particulate implants directly. There was no evidence of acute or chronic inflammation or foreign body reaction. These results should be contrasted with those of Howie et al. in which intraarticular cobalt chrome particles stimulated a rapid proliferation of macrophages and synovial degeneration after 1 week. This may be due to a direct toxic effect of metals in an intra-articular environment, the smaller particle size used in that study, or to abrasive injury to the hyaline cartilage and subsequent synovitis. Our results underscore the general inert properties of these metals in the short term, when implanted into bone in the sizes and physical forms chosen.

Animals↗
PubMed1990

Spinal metastases: the obvious, the occult, and the impostors.

Spines from 832 deceased patients with a terminal diagnosis of malignant neoplasm were examined grossly, microscopically and radiographically for evidence of tumor. Gross tumor and bone destruction or sclerosis were reliable signs of obvious metastases. Occult lesions visualized on gross sagittal sections but not detectable radiographically occurred in 26% of spines with confirmed metastatic deposits. Vertebral collapse was not a reliable indicator of metastases. Collapse was not caused by neoplasm in 22% of cases. Overall, metastases were found in 36% of patients dying from neoplastic disease. Although most metastases are obvious, occult lesions not visible radiographically occur. Collapsed vertebra may be impostors simulating metastatic disease.

Diagnosis, Differential↗
PubMed1989

Non-neurogenic soft tissue tumours of the axilla: prospective review of 16 cases.

Sixteen consecutive patients entered in a prospective study of non-neurogenic soft tissue tumours had lesions in the axilla. Delayed diagnosis and inappropriate biopsy prior to referral to a surgical oncologist were frequent findings. Sarcoma and fibromatosis were diagnosed in 14 cases, and the approaches used for these two diseases were fundamentally different. The functional outcome with limb salvage surgery in these patients is presented.

Adolescent↗
PubMed1989

The histology of a failed shelf procedure.

Clinical, radiographic and histologic findings are reported in a patient who underwent a hip shelf procedure 24 years previously. While the histologic observations confirm the presence of metaplasia of the surgically formed articular surface to fibrocartilage, there are superadded degenerative changes morphologically similar to those seen in degenerative arthritis.

Adult↗
PubMed1989

Complications and functional results after limb-salvage surgery and radiotherapy for difficult mesenchymal neoplasms: a prospective analysis.

Wide resection with adjuvant radiotherapy is generally accepted as the optimal treatment for patients with extremity soft-tissue sarcomas. However, there is a subset of patients with "difficult" tumours who sustain such marked loss of function from limb-salvage procedures that amputation might offer a superior functional alternative. To evaluate this issue, the authors prospectively designated 19 of 52 patients registered in Toronto's Princess Margaret Hospital Prospective Sarcoma Database in 1986 as "difficult" cases, on the basis of tumour size and anatomical location. Complications and functional results of wide resection and adjuvant radiotherapy were documented. The most frequent complication was related to wound healing (8 of 19 patients). Functional analysis at 1 year follow-up demonstrated that all 19 patients had results superior to those that would be expected with amputation.

Adult↗
PubMed1989

The surgical margin in soft-tissue sarcoma.

In a retrospective review of 231 patients who were referred to Princess Margaret Hospital because of a soft-tissue sarcoma in an extremity, 100 patients were identified who had no metastases when they were first seen and who had been treated by local resection and adjuvant radiation therapy. Complete data were collected for each patient for the following variables: age; sex; location of the tumor and its size, grade, depth, and compartmental status; chemotherapy; and dose of radiation. The surgical margins were characterized as positive or negative for histological evidence of disease on the basis of an independent review of the pathological and operative reports by a surgeon and a radiation oncologist who were experienced in the management of sarcoma. Cox multivariate analysis was used to determine which of these variables contributed to local recurrence and evidence of systemic disease. Adequacy of the margin of resection was the only variable that was associated with local relapse (p = 0.0004). The size of the tumor (p = 0.0008) was the major determinant of the risk of systemic disease.

Adolescent↗
PubMed1988

The effects of bulk versus particulate ultra-high-molecular-weight polyethylene on bone.

Fourteen mature New Zealand white female rabbits underwent implantation of a bulk pellet and of particulate (less than 1,000 micron) ultra-high-molecular-weight polyethylene (UHMWPE), through a drill hole in the proximal right tibia. The left tibia served as a drilled but nonimplanted control. The rabbits were killed after 16 weeks. Histologic examination of the bone-implant interface in the bulk UHMWPE group disclosed a fibrous tissue membrane with infrequent giant cell and histiocytic clusters at surface irregularities. The particulate group demonstrated positively birefringent UHMWPE fragments, rimmed by foreign body giant cells and histiocytes, embedded in a loose connective tissue. The histologic response to particulate UHMWPE is similar to that seen surrounding loose total joint arthroplasties in humans.

Animals↗
PubMed1988

The effects of bulk versus particulate polymethylmethacrylate on bone.

Twenty-one mature New Zealand white female rabbits were allocated into three groups of seven rabbits. Group I received a bolus of doughy Simplex polymethylmethacrylate (PMMA) cement injected into the proximal tibia through a drill hole. Group II received a preformed, cooled, bulk PMMA pellet. Group III had particulate PMMA powder implanted. The operated, but nonimplanted, left tibiae served as controls. Animals were killed after four months. Histologically, both Group I and Group II demonstrated a thin, fibrous tissue membrane at the implant interface. Particulate PMMA (Group III) stimulated a much thicker, florid, foreign body reaction composed of histiocytes and giant cells. The foreign body response to particulate acrylic cement was similar to that seen in failed cemented joint replacement arthroplasty in humans.

Animals↗