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PubMed1996

[Abscess of the skull base--therapy and reconstruction after zygoma resection].

Abscesses of the base of skull, if not correctly managed, can lead to the intracranial spread of infection - a life-threatening complication. Infection can spread from the upper and lower molar teeth through the retromaxillary area or the parapharyngeal space to reach the temporal, infratemporal or pterygopalatine fossa. Our recommended treatment of abscesses in these fossae is wide abscess incision together with resection of the midsection of the zygomatic arch ("Partsch method"). Two case reports are included. The first report is of a patient with cerebral abscess caused by an oral infection. The second report is of a case in which zygomatic arch reconstruction was necessary after its partial resection for abscess treatment. A new alloplastic bone-substitute material made from coral was used in the reconstruction.

Actinomycosis↗
PubMed2002

Transverse process fusion with bovine anorganic bone.

A biodegradable collagen membrane and bovine anorganic bone were studied in a rabbit spine fusion model. The bovine, anorganic bone is a nonantigenic, acellular clinical product used as a bone substitute for dento-alveolar applications. We reasoned this product with a collagen membrane could be useful for spine fusions. Our hypothesis was that bovine, anorganic bone, and a collagen membrane would promote spine fusion equivalent to an autogenous bone graft. To test the hypothesis, the transverse processes of the fourth and fifth lumbar vertebrae were decorticated in 30 rabbits divided equally among five groups. In one group, following decortication, no treatment was administered, whereas in the remaining four groups, treatments consisted of either autograft, collagen membrane, anorganic bone, or anorganic bone plus collagen membrane. Rabbits were euthanized 6 weeks after surgery, and the lumbar vertebrae were removed, radiographed, and processed for histology. The radiographs and histological sections were subjected to quantitative morphometric analyses and post hoc statistical testing (p < or = 0.05). We determined anorganic bone without a collagen membrane migrated into the soft tissues contiguous to the transverse processes. However, with a collagen membrane, the anorganic bone remained at the implant site, causing an osseous fusion of the transverse processes. Although the autograft promoted the greatest amount of new bone formation, significant transverse process fusion was accomplished with the anorganic bone and collagen membrane. Additional longer term studies are contemplated to validate feasibility of this clinical option, including a biomechanical component.

Animals↗
PubMed2004

Revascularization of a total bulk acetabular allograft at 14 years.

This case report describes the long-term outcome of a total bulk acetabular allograft placed for bone substitution after resection of recurrent pigmented villonodular synovitis of the hip joint. After 14 years in situ, the graft had completely incorporated and showed viable bleeding bone surfaces in all areas of the acetabular implant interface. The possibility of a bulk corticocancellous allograft to undergo revascularization over a long period of time has not been previously documented.

Acetabulum↗
PubMed2006

[Fence grafting for acetabular reconstruction with a cementless cup].

Acetabular reconstruction is difficult after loss of bone stock and socket remodeling. Several techniques have been proposed ranging from a metal backing to allografting. We propose fence grafting. After explantation, the acetabulum is carefully cleaned of all interface tissue and precisely measured. If the vertical diameter is clearly greater than the anteroposterior diameter, a tricortical graft is harvested from the iliac crest and modeled to perfectly fit between the anterioinferior iliac spine and the residual posterior wall as well as the fundus medially. One or two oblique screws are inserted for stabilization. Any superior bone loss is filled by bone substitute (without mechanical value). The acetabulum is then reamed from the obturator foramen sparing the anterior and posterior columns. Residual bony defects are filled with cancellous bone. A hemispheric cup is then press fit and maintained with two or three screws. We performed this procedure in eight patients with SO.F.C.O.T. stage III acetabular loosening with segmentary bone loss and an oval acetabular cavity. Clinical follow-up was more than four years. The Postel-Merle-d'Aubigné score improved from 9.8 to 15.7 on average. Radiographically, there were no implant mobilization or migration and no circumferential lucent lines were observed. A nearly anatomic position was achieved in all cases except two (technical imperfection). At more than one-year follow-up, the grafts could not be distinguished from adjacent bone. For us, high-positioned or jumbo cups do not offer a satisfactory reconstruction option. There is a risk of compression with allografts from a head bank. We have not used the cemented metal-backed solution nor impacted grafts. The major drawback with fence grafting is the iliac harvesting (possible residual limping because of the extensive disinsertion of the gluteus medius. The reliable acetabular reconstruction is the major advantage. This technique is not simply an acetabular block widened laterally but it decreases the vertical dimension. This is a reliable but minute technique which allows true long-lasting reconstruction of the acetabulum.

Adult↗
PubMed2003

Application of nonlinear phenomena induced by focused ultrasound to bone imaging.

A tissue deformability image is obtained with the vibroacoustography imaging method using mechanical low-frequency (LF) excitation. This ultrasonic excitation is created locally by means of a focused annular array emitting two primary beams at two close frequencies, f(1) and f(2) (f(2) = f(1) + f(LF)). The LF acoustic emission resulting from the vibration of the medium is detected by a sensitive hydrophone and then used to form the image. This noninvasive imaging method was demonstrated in this study to be suitable for bone imaging, with x and y transverse resolutions less than 300 micro m. Two bone sites susceptible to demineralization were tested: the calcaneus and the neck of the femur. The vibroacoustic method provides valuable ultrasonic images regarding the structure and the elastic properties of bone tissue. Correlation was made between vibroacoustic bone images, performed in vitro, and images acquired by other imaging methods (i.e., bone ultrasound attenuation and x-ray computerized tomography (CT)). Moreover, the amplitudes of vibroacoustic signals radiating from phosphocalcic ceramic samples (bone substitute) of different porosity were evaluated. The good correlation between these results and the description of our images and the quality of vibroacoustic images indicate that bone decalcification could be detected using vibroacoustography.

Aged↗
PubMed1997

Fourier-transform infrared spectroscopy study of an organic-mineral composite for bone and dental substitute materials.

A new injectable biomaterial for bone and dental surgery is a composite consisting of a polymer as a matrix and bioactive calcium phosphate (CaP) ceramics as fillers. The stability of the polymer is essential in the production of a ready-to-use injectable sterilized biomaterial. The purpose of this study was to detect possible polymer degradation which may have been caused by the interaction with the fillers using Fourier transform infrared spectroscopy. Composites containing CaP fillers (biphasic calcium phosphate, hydroxyapatite and peroxidized hydroxyapatite) and polymer (hydroxypropyl methyl cellulose) were prepared. To investigate the properties of the polymer, the inorganic and organic phases of the composite were separated using several extraction methods. The difficulty in separating the organic (polymer) from the mineral (CaP fillers) phases in the composite investigated in this study suggested the presence of strong interactions between the two phases. Spectra of extracted polymers showed new absorption bands of low intensities and indications that some chemical modifications of the original polymers have occurred. Results also indicated that the filler composition has an effect on the integrity of the polymer.

Journal Article↗
PubMed1995

Formation and properties of a synthetic bone composite: hydroxyapatite-collagen.

Composites composed of microcrystalline calcium-deficient hydroxyapatite (HAp) and collagen were formed at 38 degrees C via an acid-base reaction between calcium phosphate precursors in the presence of a collagen matrix. Formation of composites having HAp:collagen weight ratios of 4.5:1, 11:1, and 22:1, along with that of pure mineral were investigated. Isothermal calorimetry and X-ray diffraction indicated complete reaction within 5 h resulting in hardened monoliths. The rate of HAp formation increased with an increase in the proportion of collagen present. Electron microscopy indicated that the acceleratory effect of collagen was associated with the provision of nucleation sites for HAp crystallization. Analysis of the solution chemistry also showed that collagen affected the calcium and phosphate concentrations and the pH. While collagen was shown to effect the kinetics of HAp formation, the rate limiting step, as shown by X-ray diffraction and solution chemistry, was the dissolution of the acidic calcium phosphate precursor, CaHPO4. Preliminary mechanical data indicated that the Young's modulus, yield strength, and work to fracture were at the lower end of the range of those values reported for bone. The porosities observed in these composites suggest that they might be osteoinductive while their compositions should allow their eventual resorption. Thus, microstructure, kinetics, and mechanical data suggest that these composites might be suitable as bone substitutes which form in vivo.

Biocompatible Materials↗
PubMed2003

Osteoblastic differentiation of cultured rat bone marrow cells on hydroxyapatite with different surface topography.

UNLABELLED: Hydroxyapatite (HA) has been used in orthopedic, dental, and maxillofacial surgery as a bone substitute. OBJECTIVE: The aim of this investigation was to study the effect of surface topography produced by the presence of microporosity on the response of the rat bone marrow cells, evaluating: cell attachment, proliferation, total protein content, alkaline phosphatase (ALP) activity, and bone-like nodule formation. METHODS: Cells were cultured on HA discs manufactured by a combination of uniaxial powder pressing and different sintering conditions, with different percentage of microporosity (<5%-HA5, 15%-HA15, and 30%-HA30). For attachment evaluation, cells were cultured for 2 h. Proliferation was evaluated after 7 and 14 days. After 14 days, total protein content and ALP activity were measured. For bone-like nodule formation, cells were cultured for 21 days. Data were compared by ANOVA and Duncan's multiple range test when appropriate. RESULTS: Cell attachment was not affected by surface topography (p=0.37). Proliferation (p=0.001), total protein content (p=0.039), ALP activity (p=0.050), and bone-like nodule formation (p=0.00001) were all significantly decreased by the most irregular surface (HA30). SIGNIFICANCE. These results suggest that initial cell events were not affected by the surface topography of the HA. However, intermediary and final events such as proliferation, protein synthesis, ALP activity, and bone-like nodule formation favored surfaces with a more regular topography, such as that presents in HA with 15% or less of microporosity.

Alkaline Phosphatase↗
PubMed1991

Observer variability in measurements of carpal bone angles on lateral wrist radiographs.

Determinations of carpal bone angles are used in the clinical evaluation of carpal malalignment. Eleven frequently referred radiological measures in lateral projection of the wrists in 23 wrists were assessed using different definitions of axes. Interobserver- and intraobserver variations were calculated. The standard deviation of the interobserver variation ranged from 2.60 degrees to 18.15 degrees, and the intraobserver variation from 1.89 degrees to 4.66 degrees depending on the angles measured. The use of three angles for the least observer variability in assessment of carpal alignment is recommended. These angles were defined from the following carpal bone axes: radius, the line through the center of the medullary canal at 2 cm and 5 cm proximal to the radiocarpal joint; lunate, the line perpendicular to the tangent of the two distal poles; scaphoid, the tangent of the palmar proximal and distal margins, and capitate, the tangent of the dorsal margin of the diaphysis of the third metacarpal bone (substitute axis).

Adult↗
PubMed2005

Resorption of apatite-wollastonite containing glass-ceramic and beta-tricalcium phosphate in vivo.

Apatite-wollastonite containing glass ceramic is considered to be difficult to resorb, but we experienced the disappearance of the porous type of Apatite-wollastonite glass ceramic particles . In this study, the resorption of porous apatite-wollastonite glass-ceramic implanted in the femurs of rabbits was investigated, and the process was compared with beta-tricalcium phosphate, a resorbable ceramics. Porous apatite-wollastonite glass-ceramic (70, 80, and 90% porosity) and beta-tricalcium phosphate (75% porosity) were implanted in the femurs of Japanese white rabbits. Samples were harvested and examined 0, 4, 8, 12, 24 and 36 weeks after implantation. Quantitative analysis of the radiographic and histologic findings was performed with NIH Image software. Radiographic examination demonstrated that the radiopacity and size of the porous apatite-wollastonite glassceramic cylinders decreased gradually after implantation. Histologic examination revealed that the surface area of the apatite-wollastonite glass-ceramic cylinders decreased continuously, and approached 20% of the original area 36 weeks after implantation. However, the resorption rate of porous apatite-wollastonite glass-ceramic was slower than that of beta-tricalcium phosphate. Toluidine blue staining showed abundant new bone formation on the surface of the apatite-wollastonite glassceramic matrix. Considering its mechanical strength, gradual resorption characteristics, and good osteochonductive activity, porous apatite-wollastonite glass-ceramic appears to be a suitable artificial bone substitutes.

Absorption↗
PubMed2001

Periodontal regeneration of a class II furcation defect utilizing a bioabsorbable barrier in a human. A case study with histology.

This case report describes human histologic data of periodontal regeneration following guided tissue regeneration therapy (GTR) with a bioabsorbable barrier composed of polylactic acid. The tooth that was examined was part of a previously published study of the clinical effects of GTR therapy without the use of bone or bone substitutes on Class II furcation defects. Twenty-five months following the surgical procedure, the tooth was extracted for non-periodontal reasons. During this extraction, the bone within the furcation that was treated in the study was luxated with the tooth. At the completion of the study (month 12), the furcation's vertical probing depth had decreased by 2 mm with a 2 mm gain in clinical attachment. The horizontal furcation measurement decreased by 3 mm. Following extraction, the tooth was prepared for light microscopy and sectioned in the mesial-distal plane. Reference notches were not placed in the tooth at the time of surgery as there were no plans to perform histologic analysis in the study. However, using the buccal root prominences and what we interpreted to be root planing marks on the cementum, we were able to demonstrate that complete periodontal regeneration occurred on the root surface that was exposed to the pocket environment prior to surgery. New alveolar bone, cementum, and periodontal ligament were consistently observed throughout the furcation in the areas that demonstrated clinical attachment gain and a decrease in horizontal probing depth. This case report adds to the accumulating evidence of histologic periodontal regeneration following guided tissue regeneration with bioabsorbable polylactic acid barriers.

Absorbable Implants↗
PubMed1993

Induction of new bone by allogeneic demineralized bone matrix combined to bioactive glass composite in the rat.

Allogeneic diaphyseal demineralized bone matrix (DBM) cylinders containing bioactive glass rods were implanted for 4 and 8 weeks in the abdominal muscle wall of rats. DBM without glass served as control. The results suggest that new bone induction by DBM was accelerated by the presence of bioactive glass implants. However, the bone formation induced by DBM on the glass surface was relatively small. The biocompatibility of the glass was verified by the absence of adverse cellular reactions in the interface region between glass and bone. The method used provides a simple and fast means of exploring the characteristics of potential bone substitutes.

Animals↗
PubMed2003

Histological evaluation of the bone response to calcium phosphate cement implanted in cortical bone.

The aim of this study was to investigate the physicochemical and biological properties of a newly developed calcium phosphate cement (CaP cement) implanted in cortical bone. CaP cement was injected as a paste into tibia cortical bone defects in goats. Polymethylmethacrylate (PMMA) bone cement was used as a control. The animals were killed after 3 days, 2, 8, 16 and 24 weeks. X-ray diffraction and Fourier transform infrared spectroscopy performed at retrieved samples showed that the CaP cement had set as a carbonate apatite and remained stable over time. Light microscopic evaluation showed that after 2 weeks the cement was in tight contact with the bone without any inflammatory reaction or fibrous encapsulation. At later time points, the CaP cement implants were totally covered by a thin layer of bone and osteoclasts, present at the interface, which were clearly resorbing the cement. At locations where CaP cement was resorbed, new bone was deposited. Transmission electron microscopy revealed that indeed a seamless contact existed between CaP cement and bone, as characterized by the occurrence of an electron dense line of 50-60 nm thick that covered the CaP cement. Osteoblasts, in contact with the cement, were depositing new bone. Although the bulk of the material was still in situ after 24 weeks, the progressive osteoclast resorption of the cement followed by new bone formation suggests that all of the material may be replaced eventually. In contrast to the CaP cement, the PMMA reference cement was always surrounded by a thin fibrous capsule. The results indicate that the investigated CaP cement is biocompatible, osteoconductive as well as osteotransductive and is a candidate material for use as a bone substitute.

Animals↗
PubMed2005

[An experimental study on the influence of osteoporosis to bone repairing with bone matrix gelatin in ovariectomized rats].

OBJECTIVE: To study the influence of experimentally osteoporosis to osteogenic efficiency of bone matrix gelatin(BMG) implanted into the calvarial defects of rats. METHODS: Sixty-eight female SD rats of 12 +/- 1 weeks were randomly divided into two groups with 34 rats in each group. The ovaries were excised in the ovariectomized group (VG). The control group underwent sham surgery. Ninety days after ovariectomy, 10 rats from each group were examined to ensure the formation of postmenopausal osteoporosis by measuring bone density of the femur with single photon absorptiometric measurements. A critical-sized (8 mm in diameter) calvarial defect was created on the rest of 48 rats. Bone matrix gelatin was implanted to the defect. The rats were scarified at the 21st and 56th day after surgery respectively. The new bone forming capability of BMG was evaluated with undecalcified histological observation, tetracycline fluorescence marker, quantitative bone histomorphometry, At 90th day after ovariectomy, bone density of scanning electron microscopy and X-ray spectrometry. RESULTS: OVG showed very significant difference compared with the control group (0.315 +/-.015) g/cm2 vs [(0.347 +/- 0.017) g/cm2, P < 0.01 ]. At the 21st day following the implantation operation, new bone formed within the bone defects in both groups. The amount of new bone in OVG was lower than the control group. The tetracycline-labeled region in the bone defect was sparser in the OVG. At the 56th day, the bone defects healed mostly in the control group but fibrous tissue filled parts of bone defect in the OVG. The distance between two fluorescent lines of incorporated tetracycline and the mean mineralization deposition were significantly lower in the OVG than the control at the 21st day and 56th day. Mineralization of callus in OVG was inferior. Significant difference was found between the OVG and the control group in the calcium to phosphate ratio of callus in bone defects at the two time-points. CONCLUSIONS: Experimentally induced osteoporosis depressed osteogenic efficiency of BMG, suggesting that estrogen could play an important role in bone remodeling with bone substitute participating.

Animals↗
PubMed1994

[Substitution of soft tissue defects on the lower leg and foot in septic cases].

After the spontaneous epithelialisation of the defects of soft parts so called unstable scars remain which, because of ulceration, are sources of infection, endangering both soft parts and bones. Substitution with soft tissues of adequate blood supply enables the complete sanation of the septic foci and by this the rapid healing of the patient with full function. Beside this a better cosmetic result can be achieved. In septic environment, if possible, local muscle flaps and free flaps are used, depending on the extent and localization of the defect. Experiences, gained in these operations are described.

Adult↗
PubMed2004

Biological and biophysical principles in extracorporal bone tissue engineering. Part III.

Over the last decade extracorporal bone tissue engineering has moved from laboratory to clinical application. The restoration of maxillofacial bones from cell harvesting through product manufacture and end-use has benefited from innovations in the fields of biomechanical engineering, product marketing and transplant research. Cell/scaffold bone substitutes face a variety of unique clinical challenges which must be addressed. This overview summarises the recent state of the art and future anticipations in the transplantation of extracorporally fabricated bone tissues.

Animals↗
PubMed1998

Bone remodelling in the pores and around load bearing transchondral isoelastic porous-coated glassy carbon implants: experimental study in rabbits.

Cylinders of porous-coated glassy carbon were implanted into drill holes made through the articular surface of the medial condyle of both tibiae of ten rabbits for six and 12 weeks. Bone ingrowth and remodelling was examined by radiographic, histologic, oxytetracycline-fluorescence and microradiographic methods. Bone ingrowth into pores and load bearing implants was seen by all examination methods. Bone ingrowth occurred earlier when the pores were facing cancellous bone than cortical bone. Appositional bone formation occurred on the trabeculae a few millimetres from the interface during the early phase of remodelling at six weeks. At 12 weeks resorptive remodelling had occurred both in the surroundings and in those pores that face cancellous bone, whereas the amount of bone still increased in the pores facing cortical bone. In its porous-coated form glassy carbon functions well as a frame for ingrowing bone and it shows good osteoconductivity. Its mechanical properties are suitable for functioning as a structural bone substitute in places where the loads are mainly compressive. The difference between findings at six and 12 weeks indicated physiologic stress distribution and the adverse effects of stiff materials on bone remodelling were avoided by using this isoelastic material.

Journal Article↗
PubMed1989

[Materials for osteo-dural reconstruction in the cranium. An update].

Materials available for repair of a bony or dural defect at the cranial level are reviewed with particular attention stressed on their qualities and drawbacks for neurosurgical purposes. These materials include autologous or heterologous bone graft and biologically stable or biodegradable implants. No material can demonstrate ideal qualities of biocompatibility and biofunctionality. It should be either perfectly stable biologically and inert or perfectly biodegradable allowing simultaneous new bone reconstruction; moreover, it should be sterilizable, disposable, easy to handle and of low cost. Autologous grafts (iliac bone, split bone flap, pericranium...) have the best features but irradiated heterologous bone can be used instead; the latter needs a particular organization (bone graft bank) to fill the strict conditions of safety, especially regarding the risks of virus transmission. Implants have more recently been developed (acrylic, coral, B.O.P., ceramic, collagen-vicryl...) and present some drawbacks: generally high cost and not well established or insufficient biological properties. The experience of French neurosurgeons is reported from a questionnaire (102 answers) on the most frequently used materials. Autologous bone grafts, and acrylic as bone substitutes and pericranium for dural repair are preferentially used. Some materials, including coral, B.O.P. and collagen-vicryl, have a decreasing utilisation because of poor results especially with regards to bone incorporation and water tightness. Particular techniques (acrylic + teflon, acrylic with pre-op external casting and even non-repair of bone defects) are proposed by some neurosurgeons. New materials still under experimentation are finally presented (lyophilized bovine pericardium, collagen IV, polylactic acid).

Biocompatible Materials↗