[Verification of a surgical technique using a new biotitanium cage in degenerative diseases of the lumbar spine--experimental study]. / Overení operacní techniky pomocí nové biotitanové cage u degenerativního onemocnení bederní pátere--experimentální práce.

PURPOSE OF THE STUDY: Authors performed experimental PLIF operations on cadavers to verify appropriate shape and size of cage made from bioactive titan material. The approach for application into intervertebral space of the lumbar spine and appearance on X-ray and CT scans was also investigated. MATERIAL: In experiment on cadavers five implantations of interbody cages were performed, two of them in interbody space L3/L4 and three of them in L4/L5. Subtotal discectomy and end platec preparation was done before cage insertion. Our type of cage is made from bioactive titan material and fastened in the application instrument that we developed for this purpose. METHOD: To verify operational approach we used midline incision and opened spinal canal through laminectomy, partial hemilaminectomy or partial medial facetectomy. This phase was followed by discectomy and end plates preparation. Stability of inserted cages in intervertebral space is ensured by rotation and anchorage of cage wings in end plates. Operated motion segment was taken out and evaluated by X-rays and CT scans. RESULTS: The operational approach through partial hemilaminectomy and partial medial facetectomy was fully sufficient for cage application with respect to operated segment. All implantations were successful and position of cages satisfactory. Thanks to less robust gripping instrument the approach was more thrifty compared to glass-ceramic cage and comparable with commercially produced cages that we have experience with (Spine Tech, Stryker, Comesa). Due to cage radio opaque, proper position of cages is easy to control on X-ray and CT scans and allows good peroperative monitoring by X-ray magnifier. DISCUSSION: Usage of bioactive materials in spinal surgery started by introduction of glass ceramics. Based on our experience we determined suitable indications. To eliminate some of te disadvantages of glass ceramics (mainly mechanical properties), a cage made from bioactive material was developed. This type of cage does not require bone harvesting to fill the cage. This fact results in better comfort for patient in postoperative period and eliminates complications from bone graft harvesting. Bioactive surface of the cage with osseo conductive and osseo integrative features creates prerequisites for solid fusion without bone grafts. Titanium material guarantees mechanical strength and makes possible to produce a wide range of shapes and sizes. Strength of the material enables more advantageous gripping of cage in application instrument. The cage is well visible on X-ray and in MRI scans artifacts are considerably reduced. Operational approach and technique are similar to other commercially produced cages and the extent of destabilization is limited to minimum. CONCLUSION: Experimentally we repeatedly verified operational approach, suitable shape and applicability of bioactive titanium cage into intervertebral space. For clinical use bioactive titanium could be a possible way how to replace bone grafts. For spinal surgeons it represents a chemically and mechanically stable material capable of interaction in an environment where it is implanted. Even in difficult conditions the level of osseo integration is high.

Effect of plasma-sprayed hydroxyapatite coating on the osteoconductivity of commercially pure titanium implants.

Formation of a calcium phosphate layer was studied on the surfaces of plasma-sprayed hydroxyapatite (PSHA) and sandblasted commercially pure (cp) titanium in simulated body fluid with ion concentrations similar to those of human blood plasma. The PSHA surface induced the formation of calcium phosphate surface layers, while the precipitation of calcium phosphate on sandblasted cp titanium was not detected. Histologic evaluation of in vivo tests demonstrated that implants with a PSHA coating enabled the growth of bone tissue into gaps with a depth of up to 1 mm without significant formation of intermediate fibrous tissue. In comparison to sandblasted cp titanium, implants with PSHA coating exhibited greater tolerance to unfavorable conditions during healing, such as gaps at the interface or primary instability of the implant. In the case of good primary stability of the implant, filling of the gap with fibrous tissue was observed for sandblasted cp titanium implants over the greater part of the surface of gaps with a depth of 0.3 mm. Direct contact of cp titanium implants with bone was achieved only when the press-fit implantation model was used.

[Tricalcium Phosphate as a Bone Tissue Substitute (testing of biological properties in animal experiments.]. / Trikalcium fosfát jako substituce kostní tkáne (testování biologických vlastností v experimentu na zvíratech).

The authors present the results of implantations of tricalcium phosphate of LASAK Co. Prague into defects of the long bones of 12 experimental dogs after an exposure time of 2,4 and 8 months. Seven modifications of the mentioned material were used in the form of granules, prisms and powder in a total of 18 implantations. In all instances specimens after implantation were taken which did not have macroscopic or microscopic signs of inflammatory reaction. X-ray did not reveal any clear spots round the material, signalizing an inflammatory of fibrous reaction. Microscopic examination confirmed excellent tolerance of the surrounding live tissue and osteoblastic activity in the immediate vicinity of the implants. After 8 months tricalcium phosphate was still present and only a smaller size of the particles suggested its absorbability. In the discussion the authors mention some possibilities of the clinical use of this material and contemplate on the problem of absorption. Key words: bone defect, tricalcium phosphate, bioactive glass ceramics, osteoinduction, absorbability of material.

[Replacement of an intervertebral disc, using a ceramic prosthesis, in the treatment of degenerative diseases of the spine.]. / Náhrada meziobratlové ploténky pomocí keramické protézy pri lécbe degenerativních onemocnení pátere.

The authors tested in experimentally a suitable shape and approach to replacement of an intervertebral disc by means of an endoprosthesis made from glass-ceramic material of Lasak Co. In experiments on post-mortem material they succeded eventually in creating the optimal shape and finding a route of administration of the endoprosthesis into the intervertebral space. The endoprosthesis should create a spondylodesis and primary fixation of the affected portion of the lumbar spine. In some instances it thus will not be necessary, after insertion of the ceramic prosthesis into the intervertebral space, to make a supplementary instrumental fixation. Key words: ceramic endoprosthesis, replacement of degenerated lumbar intervertebral disc.

Clinical application of bioactive glass-ceramic BAS-O for filling cyst cavities in stomatology.

A description is given of the bioactive glass-ceramic material, BAS-O, and of clinical tests of this material in stomatology. Granules of BAS-O bioactive glass-ceramic were used for implantation into cyst cavities in jaw bones. Radiological examination was carried out after 3, 6 and 12 months. A total of 37 radiographs of 23 patients were recorded and evaluated. Symptoms of ossification were found in 28 cases (75.7%), while five radiographs (13.5%) did not show visible bone apposition and loss of the BAS-O granules from the operation site was found in four cases (10.8%). The authors have demonstrated the excellent healing properties and tolerance for the BAS-O material, and no significant changes were observed in biochemical and haematological examinations.

[Clinical use of BAS-O, a bioactive glass ceramic, for filling cystic cavities in stomatology]. / Klinická aplikace bioaktivní sklokeramiky BAS-O pro výplne cystických dutin ve stomatologii.

The bioactive glass-ceramic material BAS-0 and results of clinical testing of this material in stomatology are described. The granules of bioactive glass-ceramic BAS-0 were chosen for implantation into cyst cavities in jaw-bones. Radiological evaluations were carried out after 3, 6 and 12 months. Altogether 37 radiographs of 23 patients were evaluated. The symptoms of ossification were proved in 28 cases (75.7%), 5 radiographs (13.5%) were without visible apposition of the bone and in 4 cases the loss of the BAS-0 granules from operation wound was observed (10.8%). The authors proved very good healing properties and tolerance of BAS-0 material, no significant changes in biochemical and haematology examinations were observed.

Role of the glass phase in bioactive glass-ceramics.

Glass-ceramics, or composites with a glass-ceramic matrix prepared by controlled crystallization, almost invariably contain a residual glass phase. A suitable composition for the residual glass phase of bioactive glass-ceramics can be found approximately and controlled on the basis of calculation of a structural parameter Y, which in the simplified concept of the glass structure corresponds to the mean number of bridging oxygens per polyhedron in the glass lattice.

[Surface bioactive ceramics (preliminary report)]. / Povrchove bioaktivní keramika (predbezná zpráva).

The Research and Development Institute of Industrial Glass in the town of Teplice (North Bohemia) has developed bioceramics (BAS-O) with presupposed surface activity manifested during its implantation in the macroorganism. The test was carried out by means of Macor inert ceramics produced by Corning Co. In total there were performed 8 implantations of surface active bioceramics and 7 implantations of inert ceramics in the tibiae and femurs of four dogs. After two months the experimental animals were sacrificed and the implants were examined. All eight prisms of BAS-O surface active ceramics were firmly connected with the bone and could be removed from bones only by force. On the contrary, the control inert ceramics could be removed from the bone by a pincette. The contact X-ray pictures showed an interface of surrounding tissue around inert ceramics and contrary to this, in case of surface bioceramics the bone trabeculea penetrated into the implants. The surrounding fibrous tissue around inert ceramics was proved in all cases by microscopic examination. In case of surface active bioceramics the fibrous intermedial layer was not proved even by electron microscopy.

[Effect of Sulfakombin SPOFA on the dynamics of the extent of coccidiosis in small rabbit breeding operations]. / Ucinnost Sulfakombinu SPOFA na dynamiku extenzity kokcidiózy v drobných chovech králíku.

We determined the yearly changes in coccidiosis extensity applying the results of an examination of 2707 rabbits performed in the years 1981-1984. A field trial was conducted to study the efficiency of the Czechoslovak anticoccidic drug Sulfakombin Spofa administered to control coccidiosis in small rabbit breedings. We made the calculations to find out the optimum time of administration of sulphonamide substances. We discuss certain factors that influence in a decisive way the changes in coccidiosis extensity in rabbit breedings.

[Numerical calculation of basic indicators of blood acid-base balance using an equilibration method]. / Numerický výpocet základních ukazatelu acidobazické rovnováhy krve pri ekvilibracní metode.

There is a description of an algorithm of the numerical calculation of the values of actual partial pressure of CO2, actual bicarbonates, standard bicarbonates, base excess (BE), concentration of buffer bases (BB) and hemoglobin when the equilibration method of determining the acid-base balances of blood after Astrup is used. We applied the equations of the simulating curve of Siggard-Anderson nomogram to the calculations of BB and BE.

[Experimental poisoning of pheasant chicks with nitrates and nitrites in drinking water]. / Experimentální intoxikace bazantích kurat nitráty a nitrity v napájecí vode.

The effect was studied of nitrates and nitrites in drinking water on the methemoglobin level in blood and pathomorphological changes in fourteen-day-old pheasant chickens. The concentrations of 500 ppm of NO3- and 15 ppm NO2- in the drinking water were not lethal, they caused only the increase in the methemoglobin in blood to 7.1% (NO3-) and 16.5% (NO2-). The pheasants exposed to NO3- suffered from hyperaemia of liver, kidneys and mucosa of the small intestine and from the multiplication of the eosinophilic granulocytes in the villus stroma. The exposition to NO2- resulted in the non-specific dystrophic changes in liver and kidneys and in the villus edema of the small intestine. Lethal levels of nitrates and nitrites in drinking water were estimated in relation to the age of pheasants.