Bone augmentation with hydroxyapatite: histological findings in 55 cases.

Bone augmentation was performed for 55 implant patients (21 male, 34 female) with hydroxyapatite granules. In 38 patients the hydroxyapatite was covered with lyophilized dura mater to avoid its loss during the healing phase. Sixty-seven punch biopsies were obtained between 14 days and 7 years. The undecalcified specimens were embedded in poly(methyl methacrylate), sectioned and stained to demonstrate bone formation. Increasing metaplastic formation of woven bone trabeculae was observed beginning with the earliest specimens. The hydroxyapatite was in intimate contact with the bone and later was partially included within its matrix. In some areas, the woven bone was resorbed by osteoclasts together with the hydroxyapatite, and mature lamellar bone was deposited by dense layers of osteoblasts. After 20 months, sufficient new bone formation occurred to permit implant insertion. In a whole mandible specimen obtained 5.6 years after implant placement, there was almost complete ossification of the hydroxyapatite. The inclusion of the titanium implants within the newly formed bone was evident, and the hydroxyapatite granules applied during second-stage surgery were firmly embedded within the newly formed trabecular bone. The bone augmentation technique described has been used successfully in over 600 cases and can be considered as safe. Bone formation in contact with hydroxyapatite was demonstrated histologically in a large number of human biopsies.

Primary leiomyosarcoma of bone: report of eight cases.

Eight primary leiomyosarcomas of bone were registered in the files of the Basel Bone Tumor Reference Center, Basel, Switzerland, for the period 1972 to 1990. The mean age of the patients (six males and two females) was 43.7 years (range, 11 to 87 years). The tumors were located in the long bones, the fingers, and the clavicle, and presented radiologically mainly as slightly to moderately aggressive lesions (grades IB to II according to Lodwick). They reacted immunohistochemically with antibodies against alpha-smooth muscle actin (alpha-SMA), and total muscle actins (eight of eight), vimentin (seven of eight), desmin (three of eight), keratin (four of eight), type IV collagen (six of eight), laminin (five of eight), and S-100 (one of eight). Seven patients underwent surgery (five, resection; two, amputation). Some of them had received preoperative or adjuvant chemotherapy or radiation therapy. One patient with a metastasized tumor had received chemotherapy only. Tumor recurrences were observed in two cases. Four patients developed metastases of whom two were treated with chemotherapy or tumor resection. During a follow-up period of 1 to 72 months (mean, 46.5 months) four of the eight patients survived for up to 72 months, among them the only patient with grade 3 tumor and treated metastases.

[Use of hydroxyapatite (Ceros-80) in dental implantology]. / Hidroxilapatit (Ceros-80) alkalmazása a fogorvosi implantológiában.

The use of lyodura prevents the loss of hydroxyapatite crystals from the operated area during the healing period. Its protective membrane effect prevents infection and other problems during healing. Histological studies have shown that the combined use of "Ceros 80" hydroxyapatite and lyodura within 20 months resulted in the development of new, osseointegrated considerable amount of bone. This bone-hydroxyapatite bond is the base for further implantological and prosthodontic procedures.

[Importance of reference registries in bone tumor diagnosis. Experiences with the Swiss Bone Tumor Register]. / Bedeutung von Referenz-Registern in der Knochentumor-Diagnostik. Erfahrungen im Schweizer Knochentumor-Register.

Bone tumors are extremely rare. It is for this reason that in numerous places reference registries have been set up, actually cover the whole area which within the German-speaking countries. They are intended to enable more precise diagnoses on the base of their larger numbers of cases. The bone tumor registry by the Swiss Society of Pathology at the Department of Pathology of the University of Basel has been started in 1972. Today it includes about 6500 numbers of patients. Of the 4500 numbers concerning tumors of the skeleton excluding the cranium, 3000 have been sent as reference cases from Switzerland and from abroad. The importance of this kind of registry is demonstrated by the fact that in 1100 of these cases the diagnosis had to be changed by the registry, 106 times from "malignant" to "benign", and 124 times from "benign" to "malignant". The complex of problems is displayed by examples from several groups of tumors. In conclusion, the importance of a close collaboration between clinician, radiologist, and pathologist for putting up a correct diagnosis is stressed because it is the crucial condition for an optimal therapy, in particular for malignant tumors.

[Is it possible to differentiate between odontoameloblastoma and fibro-odontoma? Critical position on basis of 18 cases in DOSAK list]. / Kann man zwischen Odonto-Ameloblastom und ameloblastischem Fibro-Odontom unterscheiden? Kritische Stellungnahme auf der Basis von 18 Fällen im DOSAK-Register.

An attempt was made to differentiate between odontoameloblastoma and ameloblastic fibro-odontoma by means of histological criteria based on 29 cases referred to the DOSAK-bone tumor register. After critical revision 18 appropriate cases have been selected for evaluation. We divided them into 4 odonto-ameloblastomas and 14 ameloblastic fibro-odontomas in accordance with the WHO classification. With respect to localisation, clinical symptoms, radiography, frequency of recurrencies and age no major difference was found between the two "entities". In our sample a decisive histological differentiation was not possible. This supports our hypothesis that there is only one entity.

[Pathological anatomy of femur head necrosis]. / Pathologische Anatomie der Femurkopfnekrose.

Aseptic necrosis of the femoral head appears to have a number of etiological factors. The last steps of the pathogenetic course of events, however, is unclear. Histologically, small foci of marrow necrosis form repeatedly, particularly in the upper and medial zone of charge, and then fuse secondarily to larger areas. Secondary reparation events with ingrowth of sprouts of granulation tissue and neoformation of bone predominantly in connection with necrotic trabeculi are followed by renewed waves of necrosis, resulting in a most variegated picture in which the different phases can no longer be clearly differentiated. After the articular cartilage has been sequestrated and torn away, the uncovered spongious bone is exposed to the transforming influence of direct charge, with subsequent secondary osteoarthrosis. From the histological picture follows the modern conception of its pathogenesis: an intraosseous increase in pressure primarily infringes on the venous outflow and secondarily on the arterial inflow. These cyclic circulatory disturbances provoke the focal appearance of necrosis. As a result of this, "core decompression" follows as a therapeutic intervention that is successful in many cases.

[Six generalized and local osteopathies]. / Sechs generalisierte und lokale Osteopathien.

The remodeling of bone continues throughout life. It takes place in circumscribed areas called BMU (bone multicellular units), which during the remodeling process becomes BRU (bone remodeling units). The time span of the total remodeling process, the number of BRU and the distance in time between the appearance of these BRU in a given localization are responsible for the maintenance, or the increase or decrease, of bone substance, in particular of the trabecular bone. In bone atrophy, or osteopenia, and its clinical manifestation as osteoporosis there is decoupling of the remodeling process, with diminished bone formation which ultimately leads to perforations of the bone plates in the spongious bone. In Paget's disease of bone precipitate remodeling of bone causes the characteristic deformations. Recently, virus-RNA sequences have been shown in the bone cells, which is circumstantial evidence for a slow virus infection. Hyperphosphatasia is characterized by the same morphological alterations and discussion is currently in progress as to whether it is a congenital, or juvenile, form of Paget's disease. In osteogenesis imperfecta four different types are now distinguished; children affected by the most frequent type survive into adult life. In this condition, increased bone remodeling with insufficient bone formation is observed. In contrast, osteopetrosis, or marble bone disease, is due to an osteoclastic insufficiency and thus inadequate bone resorption. In this osteopathy a decoupling of the remodeling process has to be assumed: it is thought that other, still unknown, factors maintain regular bone formation although there is little or no bone resorption. The osteoclastic insufficiency has now been proven.(ABSTRACT TRUNCATED AT 250 WORDS)

[Histology of the implant-bone interface in cemented and uncemented endoprostheses]. / Histologie der Implantat-Knochengrenze bei zementierten und nicht-zementierten Endoprothesen.

The introduction of bone cement into endoprosthetic surgery was a significant step forward from the 'pre-cement' era. Nonetheless, its disadvantages soon stimulated the search for better means of anchoring implants without cement. Interest focuses on the so-called interface zone, which is the area between bone and foreign body. On the basis of light-microscopical findings our understanding of the biological and biomechanical interactions has influenced the principles of prosthetic design and the implant materials selected for use. The present article gives a synopsis of the histomorphology of the interface, with special reference to stability, tissue reactions, wear products, and implant fixation at bone surfaces (concerning bony ingrowth, osseointegration, and bonding). In all, 127 histological specimens of total hip and knee revisions were reviewed, in addition to a total of 24 non-cemented polyethylene cups retrieved at autopsy.

[Metastatic skipping in the bone marrow (skip metastases) in osteosarcoma. Frequency and clinical implications?]. / L'échappement métastatique dans la moelle osseuse (skip métastase) de l'ostéosarcome. Fréquence et implications cliniques?

The existence of skip metastases in osteosarcoma, a particular type of spread of this tumor, has been questioned. We have reviewed 229 cases of osteosarcomas and found two instances of skip metastases. In both the histological appearance of the metastatic forms and the primary tumor were identical. Our experience suggests that skip metastases are less frequent than originally proposed by Enneking and we discuss the possible clinical implications of our findings.

Morphometry of bone. Are parameters from the iliac crest reliable indicators of renal-insufficiency osteopathy?

Bone samples from 25 autopsy cases with chronic renal insufficiency were analyzed stereologically. The findings in the iliac crest were found to be representative of those of the rib, femur condyle and lumbar vertebra for the following stereologic parameters: volume of osteoid seems related to total bone volume [VV(OID/BONE)], surface of osteoid seams related to total bone volume [SV(OID/BONE)] and surface of osteoid seams in relation to trabecular surface [SS(OID/TRAB)]. In addition, the value of various stereologic parameters for the classification of osteopathies was checked.

Contiguous development of idiopathic osteonecrosis and osteoarthrosis in ischemia of a femoral head (radiological and morphological study).

In a 67 year-old man, an aseptic necrosis of the right hip joint developed side by side with an early oteoarthrosis characterized by an extensive narrowing of the upper interlinear space. The histological study revealed a diffuse ischemia which had evolved differently in the various regions of the femoral head. A well-limited necrosis appeared in a part of the weight-bearing zone, and osteoarthrosis developed in another one. In contrast with classical osteoarthrosis secondary to malformation, the osteoarthrotic lesions of the weight-bearing zone were caused by the ischemic angio-fibrosis of the bone marrow. At the beginning there was a resorption by the subjacent fibro-vascular tissue of the end-plate and of the deep layer of the cartilage. The osteosclerosis of this zone, in particular the eburnated plate, was formed mostly of fibre bone which rapidly became necrotic. Outside the weight-bearing zone, the subchondral angio-fibrosis and the non-inflammatory vascular pannus modified the articular surface.