The use of porous corundum ceramics in spinal surgery.

Between 1987 and 1991 the spine was stabilised in 205 patients using corundum ceramic implants. The radiological results were assessed with a follow up of from 6 to 24 months and were graded as good in 81%. Poor results were not due to the implanted material, but were usually caused by failure to obtain full correction of the deformity at operation. Porous ceramic implants produce better radiological results, with a decrease in operating time and a reduced risk of infection.

Content of metals in rabbit tissues.

The purpose of the experiments was the determination of lead, cadmium, iron, copper, zinc, manganese and magnesium in some internal organs and muscles of rabbits. The investigations were performed in 1990 with 360 white New Zealand and black-white rabbits which were slaughtered when they had 2.0 kg in weight. The experimental material (180 animals) came from a rabbit farm kept by Department of Genetics and Animal Breeding in the Agricultural Academy of Cracow. The control group constituted 180 rabbits from an area without the industry. With regard to the average lead content in 22% of kidneys and liver of experimental rabbit group an exceeding of the allowable limit and in average cadmium content in 18% of kidneys and liver was stated. The cadmium contents of values for the kidneys, liver, heart and muscles are several times higher compared with the highest values which were determined for the organs and muscles from the control area.

Porous and porous-compact ceramics in orthopedics.

A bioceramic material has been obtained by a group of researchers with the collaboration of bone surgeons and veterinary doctors. This material has the following properties: chemical composition, 97% Al2O3, 2.5% MgO, and 0.5% CaO; mineral composition, alpha-Al2O3 corundum, MgAl2O4 spinel; open porosity, 70-80%; pore diameter, more than 90% of pores between 100 and 800 microns; bending strength, approximately 15 MPa. Experiments performed on rats, rabbits, and sheep demonstrated good biocompatibility with the material implanted in their bone tissue. The outer and the inner pores were filled with the healthy bone tissue adherent to the ceramic material, and a strong biologic bond was created. The material penetrated by this mineralized bone tissue increased its mechanical strength by about 70%. These properties of the material may encourage its application to bone surgery. The porous ceramics were implanted in the bones of more than 200 patients. Observations revealed that the process of bone tissue ingrowth into the pores of material had been accomplished in two to three months. The application of the material included filling the bone cysts, postsurgical or trauma-related bone defects, destroyed vertebra caused by the removal of bone tumors, and in the alloplasty of the hip joint. A modification of the ceramic material described above has been developed: a porous-compact ceramic material that is integrally bonded and has mechanical strength several times greater than the porous one. It also enables the biologic connection with the bone. This type of material has been used for filling the dome of the acetabulum in the "coxa protrusa" and in the alloplasties of the hip joint.

[Morphologic studies of the reaction of the subcutaneous connective tissue in rats to implantation of porous ceramics]. / Badania morfologiczne reakcji tkanki lacznej podskórnej szczura na wszczep ceramiki porowatej.

In the authors carried out testing of the porous ceramics Al2O3 biocompatibility. Comminuted ceramics with an average graining 3.5 were inserted subcutaneously in suspension of physiological salt in rats. The animals were killed after 7, 15, 30, 60 and 180 days. Histologic testing of the skin together with the subcutis in the place of the ceramics' powder injection as well as testing of the internal organs was carried out. It was observed that already after 30 days the connective tissue reaction became stable and did not change until the end of the experiment. A connective tissular capsule 120-160 mu depth of collagenous fibre and some fibroblasts of the correct structure came into existence around the inserted ceramics' powder. In the course of the whole experiment neither macrophages nor great foreign bodies were observed. Accumulation of the ceramics' molecules and RES reactions were not observed in the internal organs. The tested ceramics in characterized by high tissular biocompatibility.

Application of porous bioceramic in experimental therapy of bone injuries. III. Dynamics of the callus development at the site of porous bioceramic implantation. Morphological, histochemical and histoenzymological studies.

In this work the biocompatibility of porous bioceramic implanted to the rabbit femoral bone was studied. The animals were killed 3, 6, 9, 14, 18 and 30 days after implantation and the callus with surrounding periosteum from the site of implant was taken for the studies. Morphological investigations of the callus were carried out up to the 30th day of healing of the bone tissue. Moreover, acid mucopolysaccharides level and activity of enzymes (acid and alkaline phosphatase, aminopeptidase, non-specific alpha-esterase, adenosine triphosphatase and succinate dehydrogenase) were studied up to the 18 day of the callus development. The results show that after bioceramic implantation, morphology of particular stages of the callus development, behaviour of acid mucopolysaccharides as well as localization and activity of enzymes are the same as in the normal healing process of the injured bone tissue. After 30 days total union of the mature bone tissue with bioceramic was established. We conclude that porous bioceramic satisfies the requirements for biomedical materials and may be safely used in the treatment of certain bone system diseases in humans.

Application of porous bioceramic in experimental therapy of bone injuries. II. Histoenzymological studies in the control animals.

In this work the activity of enzymes participating in the bone repair process was studied in rabbits on the 3rd, 6th, 9th, 14th and 18th day after mechanical injury of the bone tissue. The enzymes under study included acid and alkaline phosphatase, adenosine triphosphatase, non-specific alpha-esterase and succinate dehydrogenase.

Application of porous bioceramic in experimental therapy of bone injuries. I. Morphological and histochemical studies in the control animals.

The process of healing of the rabbits' bone tissue after mechanical injury was studied. The femoral bone was injured by means of oscillating saw. The animals were killed 3, 6, 9, 14, 18 and 30 days after operation and the callus with the surrounding periosteum was taken for morphological examination. Besides, acid mucopolysaccharides level and aminopeptidase activity in the callus (up to the 18th day of healing) were determined. The time of total bone union was established for 30 days.

The effect of gastric banding on body weight in experimental animals.

Recently a new method of gastroplasty has been used in operative treatment of extreme obesity in humans. It depends on putting on the stomach an inabsorbable band in order to form two reservoirs: one small upper, the other large lower, and a narrow passage connecting them, without the necessity to open the stomach. Before using this method on humans it has been experimentally examined on 19 pigs. Gastric banding has little effect on the decrease of body weight, it has some effect only in the first 3-6 weeks. Bands put on the stomach move inside it because of the excessive built-up of pressure in the upper reservoir. The reservoirs vanish. Animals quickly put up weight. The pathological mechanism of moving the band inside the stomach can be explained by the presence of two processes: one reperative, on the serose layer, the other destructive, into the stomach. These findings prove that in operative treatment of extreme obesity in humans it seems essential not to allow the pressure to build up excessively in the upper stomach reservoir.

Osteolytic lesion in chronic myelogenous leukaemia.

Destructive bone lesion of the femur was observed in one patient from a series of 103 patients with CML. Numerous myeloblasts were seen on touch preparations of the fresh surgical specimen obtained by open biopsy of the affected area. Bone marrow and peripheral blood differential count were compatible with chronic phase of CML at this time. 5 months later blastic crisis developed. Local radiotherapy produced effective palliation of pain but did not prevent blastic transformation of CML. The treatment of blastic crisis was unsuccessful and patient died 3 years after diagnosis of CML, 6 months after the first clinical evidence of bone infiltration.