MXPA99008432A - Pressure flow system and method for treating a fluid permeable workpiece such as bone - Google Patents

Abstract

A pressure flow system and method for its use are provided for contacting the interior of a fluid permeable, e.g., porous, workpiece. The system includes a fluid pressure chamber having an inlet port and an opening formed in one of the chamber walls. An adjustable seal capable of providing a fluid-tight seal about the exterior of a workpiece having a non-uniform surface is positioned within the opening. Fluid under pressure is supplied to the pressure chamber to force fluid to flow through the internal matrix of the workpiece. In a preferred embodiment, the workpiece is a bone or a section thereof, and the fluid is forced to flow from the endosteal portion of bone to the periosteal portion of bone through the vasculature and porous structure of the bone to remove blood, bone marrow and/or other non-bone constituent(s) from the bone. Alternatively, the fluid can be chosen to decontaminate and/or demineralize the bone, to stain the bone to improve visualization of the bone microvasculature or to impregnate with pharmacological agents (antibiotics, bone growth factors, etc.) so that bone can act as a delivery system.

Description

"PRESSURE FLOW SYSTEM AND METHOD FOR TREATING A WORK PIECE PERMEABLE TO FLUID AS A BONE" BACKGROUND 1. TECHNICAL FIELD This invention relates to an apparatus and method for treating e.g. clean, the inside of a fluid-permeable work piece by establishing a fluid flow using pressure differentials. More specifically, the present invention provides a pressurized flow system to provide access to the internal porous matrix of the bone that is intended for implantation with one or more treatment fluids to variably clean, degrease, sterilize and inactivate virally, disinfect and / or demineralize the bone, to facilitate the visualization of its structure or to impregnate the bone with one or more antibiotic pharmacological agents, bone growth factors, etc. so that the bone can act as a drug delivery system. 2. BACKGROUND OF THE RELATED ART The bone tissue preparation for subsequent implantation involves one or more procedures - - aseptic clean-up that is intended to minimize the risk of transferring potentially harmful disease organisms to tissue receptors, and to reduce the antigenicity associated with transplantation. The known bone cleaning procedures are not always completely and / or consistently effective. Accordingly, there is a risk that by employing any of the known bone cleaning procedures, harmful microorganisms and / or antigenic material may continue to reside in the bone. U.S. Patent No. 5,333,626 discloses a method for preparing the bone for transplantation, wherein the bone is first contacted with a decontamination agent and subsequently brought into contact with the detergent under conditions of high pressure washing at elevated temperatures. . U.S. Patent Nos. 5,513,662 and 5,556,379 disclose the application of a pressure lower than ambient pressure, that is, a vacuum to facilitate the displacement of the removable material from the internal matrix of the bone, as a method to prepare the bone for transplantation. Even though the previously described methods have had some success, difficulties have been encountered in penetrating uniformly into the bone matrix where they can - - infectious agents and / or immunogenic macro-molecules are present. Accordingly, there is a need for an improved apparatus and process for cleaning and decontaminating a bone, which minimizes the exposure of a transplant recipient to potentially harmful diseases and antigenicity related to the transplant. The system disclosed further provides a method for treating bone with agents that can result in improved performance characteristics, to act as a means to deliver one or more bioactive agents to a body where the bone is implanted to allow for dyeing of the bone for diagnosis or research purposes or to study the characteristics of the fluid flow of the bone and its microvasculature.

COMPENDIUM- In accordance with the present disclosure, a pressurized flow system and method for treating a fluid-permeable work piece are provided. The system includes at least one fluid subsystem for supplying a treatment fluid to a fluid pressure chamber. The fluid pressure chamber is constructed having an inlet port and an opening formed in one of the walls of the chamber. An adjustable seal capable of providing a fluid-tight seal around the outside of a fluid-permeable workpiece having a non-uniform exterior surface is placed within the opening. The treatment fluid under pressure is supplied to the pressure chamber from the fluid subsystem to force the fluid to flow through the internal matrix of the workpiece in order to alter, modify or otherwise affect a certain aspect of the work piece. In a preferred embodiment, the fluid-permeable workpiece is a bone or a section thereof and the fluid is a cleaning fluid or disinfectant that is forced to flow through the vasculature and porous structure of the bone to effect the removal, from bone, blood, bone marrow and / or other constituent (s) other than bone and / or sterilize and virally inactivate the bone. Alternatively, the pressure flow system can be used to demineralize the bone, to dye the microvasculature of the bone in order to improve its visualization or to introduce bioactive agents. The expression "fluid-permeable workpiece" as used herein will be understood to include any article, device or the like that allows the passage of a fluid under pressure to - - through it. The term "fluid" includes all liquid and gaseous treatment substances and mixtures thereof, which are fluent under the operating conditions of the pressurized flow system.

BRIEF DESCRIPTION OF THE DRAWINGS Various preferred embodiments are described herein with reference to the drawings, in which: Figure 1 is a schematic view of one embodiment of the pressurized flow system; Figure 2 is a side perspective view of the cleaning chamber of the pressure flow system shown in Figure 1; Figure 3 is a side perspective view with separate pieces of the cleaning chamber of the pressure flow system shown in Figure 2; Figure 4 is a cross-sectional view taken along line 4-4 of Figure 3; Figure 5 is a side partial cross-sectional view of one end of the cleaning chamber with the end plate removed and a fluid-permeable workpiece, specifically a section of bone, positioned within the opening of the chamber; - - Figure 6 is a side partial cross-sectional view of one end of the cleaning chamber with a section of bone secured therein; Figure 7 is a side partial cross-sectional view of the cleaning chamber with a section of bone secured therein and fluid under pressure being forced through the workpiece; Figure 8 is a photograph of a cross section of a portion of untreated bone; Figure 9 is a photograph of a cross section of a portion of the bone treated using the pressure flow system of this invention; Figure 10 is a photograph of a cross section of a portion of bone treated using the vacuum method; and Figure 11 is a photograph of a cross section of a portion of the bone treated using the high pressure spraying method.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The preferred embodiments of the pressurized flow system disclosed today will now be described in detail with reference to the drawings in which like reference numerals designate elements - - identical or corresponding in each of the several views. Figure 1 illustrates one embodiment of the pressurized flow system currently disclosed to be generally shown as 10. In short, the pressurized flow system 10 includes at least one pressure chamber 12 having an inlet 14 that is communicates with one end of a fluid supply manifold 16. The other end of the manifold 16 communicates with a water supply source 18 and a plurality of treatment fluid subsystems 20, 22 and 24. The subsystems 20, 22 and 24 which supply the treatment fluids to the pressure chamber 12 for treating a fluid-permeable workpiece partially mounted therein. Even when the system 10 is disclosed as having three fluid subsystems, a greater or lesser number of subsystems may be provided to adapt to the specific process being used. Water from the water supply source 18 is supplied through the water valve 7 to the manifold 16 via the pump 19. The flow controller 35 communicates with the pressure transducer 33 mounted in the pressure chamber 12 to control the speed of the pump 19 in order to maintain a constant pressure in the chamber 12. The flow transducer 32 is placed in the manifold 16 between the pump 19 and the subsystem 20 to measure the rate of water flow through the manifold 16 in upstream of subsystems 20, 22 and 24. Subsystems 20, 22 and 24 will be described in greater detail below. Referring now to Figures 2 to 4, the pressure chamber 12 includes a chamber body 59 having an opening 60 formed in one of the walls of the chamber and sized to receive a fluid-permeable workpiece 62. In the modality shown, the work piece is a bone or a section of a bone, the internal porous structure of which allows the flow of the fluid under pressure through it. Although illustrated as having a cylindrical shape, the chamber 12 can be rectangular, similar to a box of any other shape capable of supporting the bone 62 and receiving a pressurized fluid. The chamber 12 may also have multiple openings such that several of the work pieces can be accommodated in the same chamber. Preferably, the opening 60 is formed in the removable end cap 64 and secured at one end of the chamber 12, using easily removable fasteners known in the art. The end plate 64 is removable to have access to the interior of the chamber 12 to place the bone section 62 thereon and to clean the interior of the chamber 12. The band 65 can be used to secure the plate - End 64 on the body 59. An adjustable seal 66 capable of providing a fluid tight seal around the outside of the bone (which has a somewhat uneven cross section) surrounds the opening 60. The seal 66 can be any type of seal that satisfies the aforementioned requirements and advantageously is a pneumatically or hydraulically adjustable seal that can be selectively pressurized in order to sealingly engage the outer surface of the bone regardless of how uneven its cross section is. The seal 66 is held within the collar 68 positioned within the end plate 64 and the spacer member 70. A retainer plate 72 having a locking collar 74 is held in the rods 76 in front of the opening 60. The locking collar 74 is preferably aligned with the opening 60 to engage one end of the workpiece 62 to prevent that the workpiece travels within the opening 60 to result in a pressure differential across the seal 66. A signal member 78 which may be an elastomeric pad capable of deforming around the end of the workpiece 62, it can be adjusted in the locking collar 28 to provide a fluid-tight seal around one end of the workpiece 62. The retaining nuts 80 are movably secured in the - rods 76 to allow adjustment of the holding plate 72 with respect to the end plate 64. The rods 76 can also be used to secure the end plate 64, the collar 68 and the spacer member 70 in the chamber 12, although other fixing devices can also be used for this purpose. The chamber 12 is provided with a pressure gauge 82, a fluid inlet valve 84, an air vent valve 86 and a drain channel (not shown). The valves 84 and 86 may be electrically actuated valves controllable from the master controller 58 (see Figure 1). Referring now to Figures 5 to 7, the bone section 62 is secured within the chamber 12 by removing the end cap 64 from the body 59 of the chamber and by sliding the first end 88 of the bone section 6-2. through the opening 60 in the end cap 64 towards the holding plate 72. The first end 88 is placed inside the locking collar 74 in the retaining plate 72. Preferably, the position of the retaining plate 72 is adjusted on the rods 76 to place the largest portion of the length of the bone section 62 outside of the opening 60, with only a small portion of the bone being placed within the chamber 12. After the retainer plate 72 is properly adjusted, the end cap 64 can - - securing the body 59 of the chamber by moving the end cap in the direction indicated by the arrow A in Figure 5. Referring to Figure 6, the collar 68 includes a valve orifice 90 for pressing the adjustable seal 66. After the bone section 62 has been properly positioned in the pressure chamber 12 and the end cap 64 is secured in the body 59 of the chamber, the fluid pressure is supplied to the adjustable seal 66 to provide an airtight seal. fluid within the opening 60 around the bone. As illustrated in Figure 7, after the bone section 62 properly seals, the fluid at a predetermined pressure is supplied through the inlet 14 to the chamber 12. Due to the pressure differential through the adjustable seal 66, the pressurized fluid within the chamber 12 is forced into the chamber 12 through the porous internal matrix of the bone. Referring again to Figure 1, the pressurized flow system 10 is particularly suitable for treating bones, including cadaveric long bones, ileus, ribs, etc. intended for surgical implantation. In a preferred embodiment, the pressure flow system 10 for treating the bone, a fluid subsystem, e.g. a fluid subsystem 20 includes an agent - - surfactant of the anionic, cationic, amphoteric and / or non-ionic variety. Preferably, the surfactant is a suitable ethanoxy octylphenoxy nonionic ethanol 26 for removing protein and lipids from bone, such as Triton X-100 (Rohm and Haas Co.), Although other surfactants may also be used. The fluid pump 28 which is preferably a peristaltic pump even when other kinds of pumps can be used, supplies the surfactant to the manifold 16 through the electrically controlled valve 30. The flow controller 34 is operably connected to the flow transducer 32 in order to control the speed of the pump 28 and thereby control the concentration of the surfactant within the manifold 16. The cationic surfactants that may be employed include amino compounds quaternary or nitrogen; quaternary ammonium salts such as benzalkonium chloride, alkyltrimethylammonium salts and alkylpyridinium salts; mono-di and aliphatic polyamines, amines derived from rosin, amine oxides such as polyoxyethylene alkyl and alicyclic amines, N, N, N, N-tetrakis-substituted ethylene diamines, amine-bonded amines, preferably those prepared by the condensation of a carboxylic acid with a di- or poly-amine, and sodium tauro-24, 25-dihydrofusidate.

- - Anionic surfactants that may be employed include sulfates such as alkyl sulfates (e.g., sodium dodecylsulfate), sulphated oils and fats, sulfated oleic acid, sulfated alkanolamides, sulphated esters and alcohol sulfates, sulfonates such as alkylarylsulfonates, olefin sulfonates. , ethoxylated alcohol sulfates and ethoxylated alkylphenol sulfonates, fatty ester sulfates; sulphonates and sulfonates of alkylphenols; lignosulfonates; condensed sulfonates and naphthalenes, naphthalene sulfonates, dialkyl sulfosuccinates, preferably sodium derivatives, sodium derivatives of sulpho-succinates such as ethoxylated nonylphenol halide of disodium of sulfosuccinic acid; the half ester of the ethoxylated alcohol of disodium (10 to 11 carbon atoms) of sulfosuccinic acid, petroleum sulfonates such as alkali metal salts of petroleum sulfonates; for example, sodium petroleum sulfonate (Act 632); phosphate esters such as alkyl phosphate esters and a potassium salt of the phosphate ester (Triton H66); sulfonated alkyl esters (e.g., Triton GR 7); carboxylates such as those of the formula (RCOO) - (M) +, wherein R is an alkyl group having from 9 to 21 carbon atoms, and M is a metal or an amine; and the polymeric carboxylic acid sodium (Ta ol 731) and the like.

- - The nonionic surfactants that may be employed include, polyoexethylenes, ethoxylated alkylphenols, ethoxylated aliphatic alcohols, carboxylic acid esters such as glycerol esters, polyethylene glycol esters and polyoxyethylene fatty acid esters, anhydrosorbitol esters and ethoxylated anhydrosorbitol esters; glycol esters of fatty acids; natural fatty acids ethoxylates, oils and waxes; carboxylic amides such as diethanolamine condensates, and monoalkanolamine condensates; polyoxyethylene fatty acid amides, polyalkylene oxide block copolymers, preferably polyethylene oxide and polypropylene block copolymers; and polysiloxane-polyoxyalkylene copolymers; 1-dodecyl-cycloheptan-one polyethylene glycol monolaurate; and the SEPA nonionic surfactant from Macrochem. Preferred nonionic surfactants are the condensation products of ethylene oxide (polyoxyethylene) containing more than two, and preferably at least five ethylene oxide groups, with at least one end group thereof, ending by reaction with either an alcohol, aliphenol or a long chain fatty acid. A particularly preferred nonionic surfactant is a polyethoxyethanol surfactant of octylphenoxy, known as Triton X-100.

Amphoteric surfactants include N-coco-3-aminopropionic acid and its sodium salt; the disodium salts of M-bait-3-immunodipropionate and N-lauryl-3-iminodipropionate; N-carboxymethyl-N-cocoalkyl-N-dimethylammonium hydroxide; N-carboxylmethyl-N-dimethyl-N- (9-octadecenyl) ammonium hydroxide; (1-carboxyheptadecyl) trimethylammonium hydroxide; (1-carboxyundecyl) trimethylammonium hydroxide; sodium salts of N-cocoamidoethyl-N-hydroxyethylglycine and N-hydroxyethyl-N-steramide-glycine; sodium of the salts of N-hydroxyethyl-N-lauramido-B-alanine and N-cocoamide-N-hydroxyethyl-B-alanine; sodium salts of mixed alicyclic amines, ethoxylated and sulfated sodium salts or 2-alkyl-1-carboxymethyl-1-hydroxyethyl-2-imidazolinium hydroxide-free acids; the dissociation salt of 1,1-bis (carboxymethyl) -2-undecyl-2-imidazolinium hydroxide; and the sodium salt of a propoxylated and sulfated ethylenediamine-oleic acid condensate. Another fluid subsystem e.g. the fluid subsystem 22 may include an acid source 36 which is supplied to the manifold 16 via the inlet and outlet valves 38 and 40 by the pump 42. A pH controller 44 is operably associated with the pH transducer 46 mounted in the manifold 16 to control the speed of the acid pump 42 and maintain the treatment solution in the manifold 16 at a constant pH. From - Preferably, the pH controller 44 is also operably associated with the flow transducer 32 to maintain more precise control through the delivery of acid. Acids which may be employed in this operation include inorganic acids such as hydrochloric acid and organic acids such as peracetic acid. After treatment with acid, the bone is rinsed with sterile water for injection, stabilized with a stabilizing agent to a predetermined final pH, and then finally rinsed with water for injection to remove residual amounts of acid and the agent from stabilization. Another fluid subsystem e.g. the fluid subsystem 24 may include an ethanol source 48 which is supplied to the manifold 16 through the valves 50 and 52 electrically controlled by the pump 54. The controller 56 is operably connected to the pressure transducer 33 mounted in the chamber 12 to control the speed of the ethanol pump 54. The total sequence and synchronization of the operations of the subsystems 20, 22 and 24 are controlled with the input of the operator and a master controller 58 is operatively associated with the flow transducer 32 to coordinate the operation of each of these subsystems. Each subsystem can be operated alone or in - - combination with any of the other subsystems to treat the bone. Other fluids may also be provided in the system 10 in addition to, or in combination with, those already mentioned. For example, a preferred scouring / disinfecting solution is an aqueous solution of ethanol and a nonionic surfactant, with ethanol being an effective solvent for lipids and water being an effective hydrophilic carrier to allow the solution to penetrate deeper into the bone . The aqueous ethanol solution also disinfects bone by killing vegetative microorganisms and viruses. For example, the nonionic surfactant destroys lipid toga viruses such as HIV and HBV. Generally, at least about 10 percent to 40 percent water (ie, from about 60 percent to 90 percent of the degreasing agent such as an alcohol) should be present in the degreasing disinfection solution to produce optimal lipid removal and disinfection within the shortest period of time. The preferred concentration scale of the degreasing solution is from about 60 percent to 85 percent alcohol, and most preferably about 70 percent alcohol. The medically / surgically useful substances that can be delivered by the flow system a - - pressure in addition to those indicated above include, e.g., antiviricides, particularly those effective against HIV and hepatitis,; antimicrobials and / or antibiotics such as erythromycin, bacitracin, neomycin, penicillin, polymyxin B, tetracyclines, viomycin, chloromycetin and streptomycins, cefazolin, ampicillin, azactan, tobultacine, clindamycin and gentamicin, etc .; amino acids, magainins, peptides, vitamins, inorganic elements, co-factors for protein synthesis; hormones, endocrine tissues or fragments of tissue; synthesizers, enzymes such as collagenase, peptidases, oxidases, etc .; surface cell antigen scavengers, angiogenic drugs and polymeric carriers containing these drugs; collagen latex; biocompatible surfactants; antigenic agents; cytoskeletal agents; fragments of cartilage, living cells such as chondrocytes, bone marrow cells, mesenchymal stem cells, natural extracts, tissue transplants, bioadhesives, bone morphogenic proteins (BMPs), transformation growth factor (TGF-beta) -, growth factor insulin-like (IGF-1); growth hormones such as somatotropin, bone digesters; agents against tumors; fibronectin; cell attraction and fixation agents, immunosuppressants; permeation enhancers, e.g., esters - - of fatty acids such as monoesters of laureate, myristate and polyethylene glycol stearate, enamine derivatives, alpha-keto aldehydes, etc., nucleic acids, and, biodegradable polymers such as those disclosed in U.S. Patent Nos. 4,764,364 and 4,765,973 and the Application of European Patent Number 168,277. The amounts of these optionally added substances can vary widely with optimum levels being easily determined in a specific case by routine experiments. The following is an example of a preferred operating cycle of the pressurized flow system 10 for treating the bone: After the bone section 62 is secured in the pressure chamber 12, as illustrated in Figure 6, the pump 19 of water and the pump 28 are operated to supply a solution of known concentration to the pressure chamber 12. The specific solution selected will depend on the type of treatment process being carried out. The fluid can be supplied to more than one chamber 12 simultaneously, i.e., multiple pressure chambers can be provided to simultaneously treat a test of bone or bone sections. The duration of the flow may vary depending on the type of bone being cleaned. After a duration - specified, the pump 28 is disconnected, while the water pump 19 is operated to wash the system. After a specified duration of washing, the water pump 19 is switched off and the ethanol pump 54 is operated to wash the vasculature and the porous structure of the bone. In an alternative embodiment of the bone cleaning process, after the bone has been washed with an initial treatment solution, the medullary canal of the bone 62 can be sealed using the seal 78 (Figure 6). Then, the fluid that passes through the bone is forced to flow through the spongy tissue of the bone and subsequently exit the bone through the cortical tissue of the bone instead of through the medullary canal. The bone is composed of two types of tissue, cortical tissue and spongy tissue. The periosteal portion of the bone is formed of cortical tissue that has a porous structure with a large amount of solid matter. The endosteal portion of the bone is formed of porous tissue which has a sponge-like appearance, and which also includes a porous structure having small amounts of solid matter. The relative amount of each tissue class varies in different bones and within different parts of the same bone to meet the required strength requirements of the bone. The inside of the bones - long includes a central cavity called the medullary canal (see Figure 7). During bone treatment using the pressure flow system 10, fluid from within chamber 12 is forced to flow from the periosteal portion of bone 62 to the endosteal portion of bone 62 to a position beyond seal 66 within a portion of the bone 62 positioned outside of the chamber 12. The fluid is then forced to flow from the endosteal portion of the bone to the periosteal portion of the bone to exit the bone 62 out of chamber 12. It has been found that forcing the Treatment fluid that flows along the natural circulation path of the bone, ie from the endosteal portion of the bone to the periosteal portion of the bone, results in a more uniform and deeper fluid penetration into the matrix of the bone. bone, especially in the cortical bone tissue. The treatment solution can be caused to flow under a wide range of pressures. The low end of the pressure scale is limited only by the microvasculature of the bone. The pressure of the physiological impulse in the bone is approximately 10 millimeters of mercury and a pressure differential of this value or greater would be expected to provide a certain level - - of flow in this system. The upper end of the pressure scale is expected to be the pressure at which physical or biological damage occurs to the bone. The experiments have been carried out up to approximately a pressure of 3.52 kilograms per square centimeter without observed detrimental effects. The highest pressure would also be expected to be satisfactory. The following examples illustrate bone cleaning operations employing the pressurized flow system of this invention, and for comparison purposes the vacuum method described in U.S. Patent Nos. 5,513,662 and 5,563,379, the high pressure spraying method described in the patent. North American Number 5,333,626, and an untreated portion of the bone (Figure 8).

Example 1 Pressure Flow System of This Invention A human right proximal tibia was defibrated of all soft tissue and periosteum. A cut was made with a hand saw in the area of the intermediate arrow. The proximal portion (approximately 18 centimeters in length) was fixed to the pressurized flow system with an inflatable seal so that the proximal head was inside the chamber and most of the arrow was left outside. The chamber was filled with 1 percent Triton - - X-100 ™ (at 40 ° C) and pressure was established. It was observed that the fluid flowed out of the open medullary canal. First, the fluid was red and quite cloudy. After a total of 3.75 liters of solution had flowed through the bone (in about 2 minutes), the solution was virtually clear and the flow stopped. These findings were "checked by analyzing the effluent with a spectrophotometer to determine the absorbance of the solution." The channel was now capped and the flow was again established with 1-percent hot Triton X-100. The solution was now observed to flow in a multitude of small jets from the surface of the cortical intermediate arrow.After about 1 liter of the solution speaks fluid through the bone (in about 3 minutes) the flow stopped and the fluid in the chamber was changed to water The key at 37 ° C. The flow again was established until approximately 1.3 liters of fluid flow through the bone in about 5 minutes The fluid in the chamber was now changed to an aqueous solution of methylene blue was established until approximately 1 liter of the had flowed through the bone in approximately 4 minutes.The flow stopped, the bone was removed from the apparatus and the piece in cross section was cut approximately 3 centimeters from the end of - 2 - open channel. See Figure 9. The external and internal surfaces and in cross section were observed to be stained blue. A thin slice of the cross section was further milled mounted on a slice and examined microscopically. Each Haversian and Volksmann channel was observed to contain colorant. Virtually all osteocytic lacunae were observed to be blue.

Example 2 - Vacuum Method of the US Patent Number 5,556,379 A human left tibia (from the same donor as in Example 1) of all soft tissue and periosteum was defibrated. A cut was made with a manual saw and the intermediate arrow area. The channel of the next portion (approximately 18 centimeters in length) was virtually cleaned of all the marrow using a curing agent and washed with water. The vacuum line was fixed to the open end of the bone using an inflatable seal to form an air-tight seal. The bone was then immersed in a 1 percent container of Triton X-100 ™ (at 45 ° C) and a vacuum was established, using the vacuum pump. The pump was adjusted to provide a constant flow of fluid through the bone and into a trap. They pulled - - approximately 3.5 liters through approximately 11 minutes when the vacuum stopped. Then the bone was placed in a container of hot tap water and the vacuum is again set to draw approximately 2 liters of water through the bone in about 5 minutes. The bone was then placed in a container of aqueous methylene blue dye in a solution and about 1.5 liters was pulled through it in about 4 minutes. The bone was removed from the apparatus and a piece in cross section was cut approximately 3 centimeters from the end of the open channel. See Figure 10. External and internal surfaces were observed as being stained blue, but only a thin ring near the outer and inner surface was observed to be blue on the cross-sectional surface. Most of the interior remained yellow to white. A thin slice of the cross section was milled, further mounted on a slice and examined microscopically. Less than 50 percent of the Haversian and Volksmann channels were observed as containing the dye and a few of the osteocytic pools were stained blue.

Example 3 - High Pressure Spraying System of the US Patent Number 5,333,626 - - A human right distant tibia (from the same donor as Examples 1 and 2) was defibrated from all soft tissue and periosteum. A cut was made with a manual saw in the area of the intermediate arrow. The canal of the proximal portion (approximately 18 centimeters in length) was virtually cleaned of all the marrow using a healing agent and washed with water. A high pressure spraying system and spray gun were operated under pressure of approximately 140.60 kilograms per square centimeter to provide the following solutions: (A) Ten liters of Triton X-100 at 45 ° C; (B) Ten liters of water; and (C) Four liters of methylene blue dye in an aqueous solution. Spraying was focused on an area in the area of the cortical intermediate arrow. Then, a piece was cut in cross section through a cortical middle arrow. (See Figure 11). The external and internal surfaces were observed to be stained blue with regular penetration of the internal surfaces directly below the focus point of spraying. Evidence of complete penetration was absent outside the focus point of the spraying.

- - It is evident after looking at Figures 8 to 11 that the osteocytic gaps, which are the smallest recesses in the bone, can provide full access through the pressure flow system, while a smaller percentage can be achieved using the vacuum method. and the method of high-pressure spraying when the systems are operated under comparable parameters and conditions. As discussed in the foregoing, the pressure flow system 10 can be used to carry out treatment procedures, in addition to cleaning. For example, the pressurized flow system 10 can be used to effect the demineralization of the bone by forcing an acid or other demineralization agent through the bone. This can be achieved by activating the water pump 19 and the acid pump 42 to supply an acidic solution to the pressure chamber 12. After a specified duration, the acid pump 42 can be deactivated and the water pump 19 be operated alone to wash the acid from the bone. When the bone has a significant cross-sectional dimension, current demineralization methods (e.g. acid bath) result in demineralization proceeding by a solvent front process. This results in a bone that retains a certain amount of mineral matter that increases toward its center. In contrast, the pressure flow system described in the - - present provides a demineralized bone that has a more uniform demineralization profile than these current methods, essentially increasing the porosity by demineralizing the vascular channels through the bone. This system is intended to be used to develop allograft forms that can provide structural support, but which have improved ability to be remoulded in a host bone due to improved vascular access through the demineralized micropore structure of bone. This process will allow the development of allografts that carry an osteoinductive weight. It will be appreciated that various modifications may be made to the embodiments disclosed herein. For example, the flow system does not need to be used to clean or demineralize but instead can be used as a histology tool. Due to the pressure flow system described above, which has been shown to be effective in penetrating the mineralized tissue, the system can be used to inject a dye or any other suitable contrast agent e.g. a methylene blue dye in the smaller recesses of the bone, including the osteocytic gaps to improve the visualization of these tiny structures and to better allow the study of the microvasculature of the bone. The camera can also be used to study the mechanics of fluid flow through the microvasculature of bone. It can also be used to impregnate the bone with pharmacological agents (antibiotics), bone growth factors, etc. so that the bone can act as a delivery system. In addition, more than one pressure chamber may be used simultaneously to treat one or more workpieces. For example, an entire bone can be treated by securing one end of bone within a first pressure chamber and the other end of the bone within a second pressure chamber. In yet another example, a pressure chamber may include more than one opening having a seal placed in each opening to facilitate the simultaneous processing of several workpieces using a single chamber. Therefore, the foregoing description should not be construed as limiting, but simply as exemplifications of the preferred embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

Claims (29)

- - R E I V I N D I C A C I O N S

1. A pressurized flow system for treating the inside of a fluid-permeable workpiece with a fluid comprising: a) a fluid pressure chamber having a fluid inlet orifice and an aperture formed through a fluid wall; the dimensional chamber to allow the passage of at least a portion of the work piece therethrough; and b) a pressurizable seal placed around the opening conformable with the surface of the workpiece and capable of fluid-tight coupling therewith, wherein when the fluid pressure chamber is pressurized, fluid from the pressure chamber flows from the pressure chamber through the inside of the workpiece and out of the workpiece to the outside of the pressure chamber.

2. A pressurized flow system according to claim 1, wherein the pressurizable seal is pressurized with a gas or a liquid.

3. A pressurized flow system according to claim 1, further comprising a retainer to prevent movement of the workpiece.

4. A pressurized flow system according to claim 3, wherein the retainer includes a plate fixed adjustably to the exterior of the fluid pressure chamber.

5. A pressurized flow system according to claim 4, further comprising a sealing device supported by the retainer, the sealing device is positioned to couple and seal one end of the workpiece.

6. A pressurized flow system according to claim 1, further comprising at least first and second sources of fluid communicating with the fluid inlet orifice.

7. A pressurized flow system according to claim 6, wherein the workpiece is a bone, the first fluid source is a surfactant and the second fluid source is ethanol

8. A pressurized flow system according to claim 7, wherein the surfactant is a polyethoxyethanol of octylphenoxy.

9. A pressurized flow system according to claim 6, further comprising a control means for automatically controlling the ratio of the first and second fluids supplied to the pressure chamber by the first and second fluid sources. - -

10. A method for treating the inner matrix of a fluid-permeable workpiece comprising: a) providing a fluid pressure chamber; b) placing at least a first portion of a fluid-permeable workpiece within the interior of the fluid pressure chamber, and at least a second portion of the workpiece to the exterior of the fluid pressure chamber; and c) supplying a fluid at a pressure greater than atmospheric pressure to the fluid pressure chamber to force the fluid to flow from inside the chamber through the interior matrix of the workpiece to a location outside the chamber of fluid pressure.

11. A method according to claim 10, further comprising the step of providing an adjustable seal around an opening in the fluid pressure chamber, the adjustable seal providing a fluid-tight seal around the permeable workpiece. to the fluid

12. A method according to claim 10, wherein the fluid-permeable workpiece includes a bone or a section thereof, and the fluid is selected from the group consisting of water, soaps, solvents, bioactive agents. , sterilization agents, antimicrobials, preservatives, colorants and demineralization agents

13. A method according to claim 10, wherein the step of supplying the fluid includes supplying at least a first and a second fluid. A method according to claim 12, wherein the fluid includes a soap and is supplied to clean and / or disinfect the internal matrix of the bone. 15. A method according to claim 14, wherein the soap is a surfactant which is selected from the group consisting of cationic surfactants, anionic surfactants, nonionic surfactants and amphoteric surfactants. 16. A method according to claim 12, wherein the fluid is a demineralization agent that includes an acid. 17. A method according to claim 12, wherein the fluid is a dye that stains the internal bone matrix. 18. A method according to claim 12, wherein the step of supplying a - fluid includes sequentially supplying a surfactant and ethanol. 19. A method according to claim 18, further comprising 1 step of automatically controlling the sequence and synchronization of the fluid supply. 20. A method according to claim 12, wherein the fluid is a bioactive agent that is selected from the group consisting of bone morphogenic proteins (BMPs), bone active agents, transforming growth factors (TGF-beta) , insulin-like growth factors (IGF) and other growth factors, including PDGF and FGF. 21. A method according to claim 10, wherein the fluid-permeable workpiece includes bone or a section thereof, and the fluid is selected from the group consisting of pharmacological agents, including antibiotics and hormones. 22. A method for treating the inner matrix of the bone that comprises forcing a treatment fluid to flow from the endosteal portion of the bone to the periosteal portion of the bone to force the bone out. 23. A method according to claim 22, wherein the treatment fluid is selected from the group consisting of water, soaps, - - solvents, bioactive agents, sterilization agents, antimicrobial preservatives, dyes and demineralization agents. 24. A method according to claim 23, wherein the treatment fluid includes a soap and is supplied to clean and / or disinfect the inner matrix of the bone. 25. A method according to claim 24, wherein the soap is a surfactant that is selected from the group consisting of cationic surfactants, anionic surfactants, nonionic surfactants and amphoteric surfactants. 26. A method according to claim 22, wherein the treatment fluid is a demineralization agent. 27. A method according to claim 22, wherein the treatment fluid is a colorant. 28. A method according to claim 22, wherein the fluid is a bioactive agent that is selected from the group consisting of bone morphogenic proteins (BMPs), bone active agents, transforming growth factors (TGF- - - beta), insulin-like growth factors (IGF) and other growth factors, including PDGF and FGF. 29. A method according to claim 22, wherein the treatment fluid is selected from the group consisting of pharmacological agents, including antibiotics and hormones. - SUMMARY OF THE INVENTION A pressurized flow system and method are provided for contacting the interior of a fluid permeable work piece, e.g., porous. The system includes a fluid pressure chamber having an inlet orifice and an opening formed in one of the walls of the chamber. An adjustable seal capable of providing a fluid-tight seal around the outside of a workpiece having a non-uniform surface is placed within the opening. Fluid under pressure is supplied to the pressure chamber to force the fluid to flow through the internal matrix of the workpiece. In a preferred embodiment, the workpiece is a bone or a section thereof and the fluid is forced to flow from the endosteal portion of the bone to the periosteal portion of the bone through the vasculature and the porous structure of the bone to remove from the bone. the bone and blood, the bone marrow and / or any other constituent (s) other than bone. Alternatively, the fluid can be selected to decontaminate and / or demineralize the bone, to dye the bone in order to improve the visualization of the bone microvasculature and to impregnate with pharmacological agents (antibiotics, growth factors of bone, etc.) so that the bone can act as a delivery system.