Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
  • A61B17/88—Osteosynthesis instruments; Methods or means for implanting or extracting internal or external fixation devices
  • A61B17/8802—Equipment for handling bone cement or other fluid fillers
  • A61B17/8833—Osteosynthesis tools specially adapted for handling bone cement or fluid fillers; Means for supplying bone cement or fluid fillers to introducing tools, e.g. cartridge handling means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
  • B01F25/40—Static mixers
  • B01F25/45—Mixers in which the materials to be mixed are pressed together through orifices or interstitial spaces, e.g. between beads
  • B01F25/451—Mixers in which the materials to be mixed are pressed together through orifices or interstitial spaces, e.g. between beads characterised by means for moving the materials to be mixed or the mixture
  • B01F25/4512—Mixers in which the materials to be mixed are pressed together through orifices or interstitial spaces, e.g. between beads characterised by means for moving the materials to be mixed or the mixture with reciprocating pistons
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
  • B01F25/40—Static mixers
  • B01F25/45—Mixers in which the materials to be mixed are pressed together through orifices or interstitial spaces, e.g. between beads
  • B01F25/452—Mixers in which the materials to be mixed are pressed together through orifices or interstitial spaces, e.g. between beads characterised by elements provided with orifices or interstitial spaces
  • B01F25/4521—Mixers in which the materials to be mixed are pressed together through orifices or interstitial spaces, e.g. between beads characterised by elements provided with orifices or interstitial spaces the components being pressed through orifices in elements, e.g. flat plates or cylinders, which obstruct the whole diameter of the tube
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F31/00—Mixers with shaking, oscillating, or vibrating mechanisms
  • B01F31/65—Mixers with shaking, oscillating, or vibrating mechanisms the materials to be mixed being directly submitted to a pulsating movement, e.g. by means of an oscillating piston or air column
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
  • B01F35/71—Feed mechanisms
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
  • B01F35/71—Feed mechanisms
  • B01F35/712—Feed mechanisms for feeding fluids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
  • B01F35/71—Feed mechanisms
  • B01F35/716—Feed mechanisms characterised by the relative arrangement of the containers for feeding or mixing the components
  • B01F35/7161—Feed mechanisms characterised by the relative arrangement of the containers for feeding or mixing the components the containers being connected coaxially before contacting the contents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
  • B01F35/71—Feed mechanisms
  • B01F35/716—Feed mechanisms characterised by the relative arrangement of the containers for feeding or mixing the components
  • B01F35/7163—Feed mechanisms characterised by the relative arrangement of the containers for feeding or mixing the components the containers being connected in a mouth-to-mouth, end-to-end disposition, i.e. the openings are juxtaposed before contacting the contents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
  • B01F35/71—Feed mechanisms
  • B01F35/717—Feed mechanisms characterised by the means for feeding the components to the mixer
  • B01F35/7174—Feed mechanisms characterised by the means for feeding the components to the mixer using pistons, plungers or syringes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
  • B01F35/75—Discharge mechanisms
  • B01F35/754—Discharge mechanisms characterised by the means for discharging the components from the mixer
  • B01F35/75425—Discharge mechanisms characterised by the means for discharging the components from the mixer using pistons or plungers
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
  • A61B17/88—Osteosynthesis instruments; Methods or means for implanting or extracting internal or external fixation devices
  • A61B17/8802—Equipment for handling bone cement or other fluid fillers
  • A61B17/8805—Equipment for handling bone cement or other fluid fillers for introducing fluid filler into bone or extracting it
  • A61B17/8827—Equipment for handling bone cement or other fluid fillers for introducing fluid filler into bone or extracting it with filtering, degassing, venting or pressure relief means

Definitions

• the present invention relates to bone cement mixing devices, related systems, and methods of use thereof.
• Bone cements are used in orthopedic procedures for filling bone voids and repairing defects. They typically comprise a cement powder that is mixed with a liquid and manually applied to the defect site. The mixed cement may also be transferred into a delivery device and injected into the site.
• Current mixing and delivery systems rely on manual open mixing, such as a bowl and spatula, which can be messy and difficult to achieve uniformity. The open mixing and transfer steps also present contamination risk. Furthermore, the transfer step is messy and time consuming. Thus, there is a need for a better bone cement mixing and delivery system.
• the present invention features an enclosed bone cement mixing and delivery system.
• the present mixing and delivery system is based on syringe-to-syringe mixing, which eliminates the open mixing and transfer steps and reduces contamination risk and preparation time.
• the system also improves cement i ⁇ jectability and includes a packaging design that promotes powder filling and extends shelf life.
• the invention features a mixing and delivery system that includes first and second rigid tubes containing movable pistons, in which the tubes are joined end-to-end such that there is communication between the tubes that allows fluid to move between the tubes, and wherein at least one of the tubes includes a bone cement powder.
• the application of force to alternate pistons produces high shear during the mixing step.
• the tubes and pistons are provided as disposable syringes.
• the syringes have Luer tips.
• the pistons are capable of moving independent of one another.
• Bone cement powder is filled into one of the two tubes.
• the powder is a calcium phosphate composition.
• the calcium phosphate composition includes amorphous calcium phosphate, poorly crystalline calcium phosphate, hydroxyapatite, carbonated apatite (calcium-deficient hydroxyapatite), monocalcium phosphate, calcium metaphosphate, heptacalcium phosphate, dicalcium phosphate dihydrate, tetracalcium phosphate, octacalcium phosphate, calcium pyrophosphate, or tricalcium phosphate, or mixtures thereof.
• the calcium phosphate composition includes an amorphous calcium phosphate and a second calcium phosphate source, e.g., poorly crystalline calcium phosphate, hydroxyapatite, carbonated apatite (calcium-deficient hydroxyapatite), monocalcium phosphate, calcium metaphosphate, heptacalcium phosphate, dicalcium phosphate dihydrate, tetracalcium phosphate, octacalcium phosphate, calcium pyrophosphate, or tricalcium phosphate, or mixtures thereof.
• the calcium phosphate composition is a powder described in or prepared according to the methods disclosed in, e.g., U.S. Patent No. 5,650,176, U.S. Patent No. 5,783,217, U.S. PATENT
• the calcium phosphate composition has an average crystalline domain size of less than 100 nm (e.g., in the range of between about 1 nm to about 99 nm; preferably 50 nm or less; more preferably 10 nm or less).
• the calcium phosphate composition has a tap density of between about 0.5 g/cm 3 to about 1.5 g/cm 3 , preferably the calcium phosphate composition has a tap density of greater than about 0.7 g/cm 3 (e.g., about 1.0 g/cm 3 ).
• the calcium phosphate composition includes a supplemental material, e.g., a biocompatible cohesiveness agent or a biologically active agent (see, e.g., the biocompatible cohesiveness agents and biologically active agents as described and defined in U.S. Patent Application Publication No. 2007/0128245; incorporated hereby by reference).
• the biocompatible cohesiveness agent is present in the calcium phosphate composition in an amount in the range of about 0.5 wt % to about 20 wt % (e.g., less than about 20 wt%, preferably less than about 10 wt %, more preferably less than about 5 wt %, and most preferably less than about 1 wt %).
• the powder is compressed to a desired density to enhance the wetting characteristics, optimize mixing forces, and minimize the amount of air in the PATENT
• the powder has a density in the range of about 0.1 to about 1.2 g/cc, preferably, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, or 1.2 g/cc, and most preferably 1.0 g/cc.
• the tube with powder has an affixed porous cap to aid powder filling and compaction by venting air; the porous cap allows air to escape from the tube, but prevents escape of the powder.
• the porous cap has pores that are less than or equal to 1.0 mm in diameter, preferably less than or equal to 750, 500, 300, 250, 150, and 100 ⁇ m in diameter, and more preferably less than 75, 50, 25, 15, 10, and 5 ⁇ m in diameter, and most preferably less than or equal to 1, 0.5, 0.4, 0.3, 0.2, 0.1, and 0.05 ⁇ m in diameter.
• the cap also allows released moisture to exit the device, which extends shelf life and long term stability of the powder during storage by preventing degradation of the powder components.
• the cap is composed of a porous polymer, ceramic, or metal material.
• the second tube is filled with a liquid.
• the liquid is a physiologically-acceptable fluid including but are not limited to water, saline, and phosphate buffers.
• the fluid can be a biological fluid, e.g., any treated or untreated fluid (including a suspension) associated with living organisms, particularly blood, including whole blood, warm or cold blood, and stored or fresh blood; treated blood, such as blood diluted with at least one physiological solution, including but not limited to saline, nutrient, and/or anticoagulant solutions; blood components, such as platelet concentrate (PC), apheresed platelets, platelet-rich plasma (PRP), platelet-poor plasma (PPP), platelet-free plasma, plasma, serum, fresh frozen plasma (FFP), components obtained from plasma, packed red cells (PRC), buffy coat (BC); blood products derived from blood or a blood component or derived from bone marrow; PATENT
• the calcium phosphate composition once hydrated, forms a paste.
• Varying amounts of a liquid may be added to the powder to produce a paste having one or more desired characteristics.
• 0.3-2.0 cc of liquid per gram of powder is used to prepare a paste that is formable, i.e., capable of being molded and retaining its shape.
• the paste is injectable, i.e., capable of passing through a 16- to 18-gauge needle.
• the paste can also be prepared for delivery through a catheter (e.g., a catheter having a 7-15 gauge needle, and more preferably a 7, 8, 9, 10, 1 1 , 12, 13, 14, or 15 gauge needle).
• the powder-containing tube and the liquid-containing tube can be joined end-to- end such that there is communication between the tubes that allows fluid to move between the tubes.
• the tubes are joined using a Luer connector, which provides a tight seal to prevent leakage and contamination.
• Mixing of the powder and liquid is initiated by pressing a piston in the liquid- containing tube, which forces the liquid through the connection into the powder present in the powder-containing tube.
• the liquid is allowed to soak into the powder.
• the liquid is allowed to soak into the powder for 1 , 2, 3, 4, 5, 10 seconds, preferably 30 seconds or 1 , 2, 3, 4, or 5 minutes, or more preferably 10, 15, 20, or 30 minutes.
• gas may be entrapped within the material.
• the gas is selected from carbon dioxide, air, nitrogen, helium, oxygen, and argon. The gas can be removed by disconnecting the two tubes and repositioning the pistons until all gas is expelled, keeping the solid and liquid content PATENT
• ATTORNEY DOCKET NO. 04712/063WO2 within the tubes. This venting step improves the mixing and mechanical properties of the material.
• the two tubes are reconnected after venting the gas.
• Mixing is resumed by alternately applying pressure to the pistons present in the tubes to transfer the hydrated and unhydrated material through the connector from one tube to the other.
• mixing continues until the material is substantially completely hydrated. If all material does not transfer, the material is alternately pressed back and forth between tubes until it all flows and is uniformly hydrated and mixed.
• the orifice formed from the joining of the two tubes is sized such that it breaks agglomerates and renders the cement more injectable.
• the orifice is 5.0, 4.0, 3.0, 2.0, or 1.0 mm in diameter, preferably the orifice is 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 mm in diameter.
• the hydrated material which is preferably in a paste form, is dispensed substantially completely into one of the two tubes for delivery.
• the second tube is disconnected from the first tube.
• one of the two tubes used for mixing is a delivery syringe, which is used to deliver the hydrated powder material once it is substantially mixed (e.g., to a site in a human patient requiring bone cement).
• a delivery tip such as a needle, can be attached to the end of the delivery syringe to deliver the material (e.g., using a Luer connector).
• the substantially completely mixed and hydrated material is sterile.
• the calcium phosphate material after hydration and hardening, has a porosity of about 5%, more preferably the material is about 10, 20, or 30% porous, PATENT
• the material is about 40, 50, or 60% porous.
• the calcium phosphate material is at least about 20% porous.
• the hydrated material has a Ca/P ratio of less than 1.67.
• the hydrated material is a paste that hardens to form a calcium phosphate having an overall Ca/P molar ratio in the range of 1.0-1.67, preferably 1.3- 1.65, more preferably 1.4-1.6, and most preferably close to that of naturally-occurring bone, that is in the range of 1.45 to 1.67.
• the hardened calcium phosphate composition has a Ca/P molar ratio of equal to or less than about 1.5.
• the hardened calcium phosphate composition exhibits a compressive strength of equal to or greater than about 1 or 2 MPa.
• the compressive strength is in the range of about 1 MPa to about 150 MPa (e.g., 20, 30, 40, 50, 60, 70, 80, 90, or 100 MPa).
• the compressive strength is 120 MPa or greater (e.g., 120 to 150 MPa).
• the compressive strength is in the range of about 20-30 MPa.
• a second aspect of the invention features a method of bone repair that includes administering the hydrated material prepared using the mixing system of the first aspect of the invention.
• the hydrated material is a formable, self-hardening, paste, which is moldable and cohesive when applied to an implant site in vivo, and hardens to form a calcium phosphate composition.
• the paste hardens to form a calcium phosphate composition (e.g., a poorly crystalline apatitic (PCA) calcium phosphate) having significant compressive strength.
• the hydrated material may be implanted in vivo in paste form or as a hardened calcium phosphate.
• the composition can be used to repair bone, e.g., damaged bone, or as a delivery vehicle for PATENT
• the term “substantial” or “substantially” means sufficiently to accomplish one or more of the goals, applications, functions and purposes described herein.
• “substantially mixed” means that one or more powder components used in conjunction with the mixing devices of the invention are mixed with one or more other components (one or more of which may be an aqueous fluid) to near homogeneity such that the mixture is relatively or nearly uniform in composition.
• the mixture forms a slurry, paste, or cement, and is injectable.
• Fig. 1 is a plan view of the packaged device with powder and porous cap.
• Fig. 2 is a disassembled view of the mixing and delivery system.
• Fig. 3 is a cross section of the mixing device assembly.
• Fig. 4 is a graph showing the average number of passes/strokes used to hydrate 6.0 grams of a calcium phosphate compressed to the indicated density with 3.0 cc of saline using the mixing device of the invention.
• powder 101 is filled into barrel 100 and compressed to occupy a desired density (e.g., between 0.1 g/cc and 1.1 g/cc) within barrel 100 and stopper 103.
• Luer connector 105 is attached to tip 104, and porous cap 112 is attached to Luer connector 105.
• This device may be packaged within a moisture barrier configuration along with desiccant as preservative (not shown).
• a desiccant is defined as any material with an affinity for moisture higher than that of the protected product; examples include but are not limited to clay, silica gel, or molecular sieve.
• barrel 100 contains powder 101 and a movable plunger
• a second barrel 106 can be filled with liquid 1 10 by retracting movable plunger 107. Rubber stoppers 103 and 108 prevent leakage of contents from the barrels.
• Barrels 100 and 106 have Luer fittings 104 which are connected using Luer connector 105, which provides a leak-tight seal.
• barrels 100 and 106 are of different capacities and can accommodate various powder and liquid volumes.
• one or both of the barrels of the mixing device into which the bone cement powder and liquid are added can be 1 , 2, 3, 4, 5, 6, 7, 8, 9, or 10 cc, preferably 15, 20, 25, 30, 35, 40, 45, or 50 cc, more preferably 60, 70, 80, 90, or 100 cc, and most preferably 150, 200, 250, 300, 350, 400, 450, or 500 or more cc in volume.
• the device can be manufactured so that the barrels of the device hold the same volume or different volumes, and the barrels can be filled with the same or different volumes of components (e.g., bone cement powder or liquid).
• the liquid PATENT e.g., the liquid PATENT
• (cc):powder (g) ratio is 0.1 , 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 , and 1.5: 1 , preferably 2, 3, 4, 5, 6, 7, 8, 9, or 10: 1 , more preferably 15, 20, 25, 30, 35, 40, 45, or 50: 1 or more.
• the mixing device includes barrel 100, which is filled with calcium phosphate powder 101 , and piston/plunger 102, which is inserted into barrel 100.
• Depressing piston/plunger 102 compresses the calcium phosphate powder to a desired density to reduce air content, facilitate wetting, and allow easy mixing.
• Barrel 100 also includes porous cap 1 12, which is attached at the distal end of barrel 100 to permit easy filling and compression. Porous cap 1 12 allows gas present in barrel 100 to vent when depressing piston/plunger 102 while retaining calcium phosphate powder 101 in barrel 100. Compression of the calcium phosphate powder in the device to 0.8 g/cc or less produces a poorly and ineffectively mixed paste following hydration. The same powder, when compressed to a density of 1.0 g/cc and hydrated, is effectively and uniformly wetted and mixed.
• the mixing device also includes barrel 106, which is adapted to accept a needle, e.g., a 16 gauge needle, which is attached at the distal end of barrel 106.
• a needle e.g., a 16 gauge needle
• Liquid 1 e.g., USP saline
• the needle is removed from the distal end of barrel 106 and barrel 106 is coupled to barrel 100 using Luer fittings 104 to form Luer connector 105.
• the saline is injected into calcium phosphate powder 101 by depressing piston/plunger 107, which injects the saline into barrel 100. After a brief delay to allow the liquid to wet the powder, air is vented by disconnecting barrel 100 PATENT
• Barrel 100 and barrel 106 can be composed of clear polycarbonate to allow easy visualization during the venting step. Barrel 100 is reconnected to barrel 107 and mixing is performed by alternately and rapidly depressing pistons/plungers 102 and 107 several times until a uniform mixture (e.g., a paste) is formed (approximately 3-20 times). In the event not all material passes between barrel 100 and barrel 106, a series of alternating passes of plungers 107 and 102 can be performed until all material transfers and a uniform mixture is achieved.
• a uniform mixture e.g., a paste
• the narrow orifice that connects barrel 100 to barrel 106 increases shear, reduces agglomerates, and improves homogeneity and injectability of the mixture.
• the fully mixed paste is transferred into barrel 106, which is disconnected from barrel 100.
• a delivery needle or cannula (not shown) is attached to barrel 106 at Luer tip 104 and the cement can be fully extruded through the needle.
• the mixed material is injectable, i.e., capable of passing through a 7- to 18-gauge needle.
• the paste can also be prepared for delivery through a catheter (e.g., a catheter having a 7-15 gauge needle, and more preferably through a 7, 8, 9, 10, 1 1, 12, 13, 14, or 15 gauge needle).
• Barrel 100 and piston/plunger 102 combine to form the powder syringe, while barrel 106 and piston/plunger 107 combine to form the delivery syringe, both of which can be obtained from various industry suppliers.
• Barrel 100 and barrel 106 can be independently manufactured from glass or plastic (e.g., polypropylene, polyethylene, polycarbonate, polystyrene, and the like).
• Pistons/Plungers 102 and 107 include a plastic PATENT
• Barrel 100 is filled with calcium phosphate powder 110 (e.g,. any of the calcium phosphate powders described herein).
• Porous cap 1 12, which includes a porous polymer insert and a Luer connector, can be obtained from B.Braun (e.g,. SAFSITE® Capped Valve System; ULTRASITE® Capless Valve System).
• the mixing device can also include a standard hypodermic needle, which can be obtained from various industry suppliers.
• the powder syringe is placed into a moisture barrier tray along with a silica gel desiccant canister (e.g., a thermoformed tray inside a foil pouch may be used or a moisture barrier tray formed from a poly(ester) copolymer of terephthalic acid, ethylene glycol and cyclohexane dimethanol known as "PETG" can be used; see, e.g., U.S. Patent No. 4,284,671 ; incorporated herein by reference).
• a silica gel desiccant canister e.g., a thermoformed tray inside a foil pouch may be used or a moisture barrier tray formed from a poly(ester) copolymer of terephthalic acid, ethylene glycol and cyclohexane dimethanol known as "PETG” can be used; see, e.g., U.S. Patent No. 4,284,671 ; incorporated herein by reference).
• This moisture barrier configuration preserves the product (i.e., the calcium phosphate powder) by allowing moisture transmission through the porous cap so that it can be absorbed into the desiccant; the device design is particularly effective at elevated temperatures which would normally lead to cement degradation.
• the cement composition within the mixing device was degraded within 2 weeks at 50 0 C without desiccant, but was intact after 4 months with desiccant.
• Example 2 To demonstrate the ability of the present device and its method of use to simplify preparation and to enhance injectability of a conventional calcium phosphate cement
• CPC precursors Two CPC precursors; an amorphous calcium phosphate (ACP) (with Ca/P ⁇ l .5) and dicalcium phosphate dihydrate (DCPD) seeded with apatite (10-25% w/w) were prepared using a low temperature double decomposition technique.
• the two powders were mixed at a 1 : 1 ratio and milled in a high-energy ball mill for 3 hours.
• the resulting powder was filled into a syringe and connected to a second syringe filled with saline by means of a luer connector.
• the saline was injected into the powder at a liquid to powder PATENT
• Syringe mixing reduced preparation time from two minutes to one minute, and the cement was deliverable through a 16 gauge needle with less than 3kgf force. A 50% reduction in injection force relative to bowl mixed materials was observed. Syringe mixing also increased the percentage of CPC delivered. The delivered amount was less than 90% for bowl mixed cement but was 100% for syringe mixed cement. Syringe mixed cement could be stored for up to 6 minutes at room temperature and remixed while retaining full injectability. The mixing did not affect the hardening rate, compressive strength, or resistance to washout of the CPC, nor did it change the chemical composition. The injectable cement hardened in less than 5 minutes at 37°C, achieved a compressive strength of 30 MPa in 2 hours and could be injected directly into a water bath without loss of material.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Orthopedic Medicine & Surgery (AREA)
• Surgery (AREA)
• Dispersion Chemistry (AREA)
• Heart & Thoracic Surgery (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
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• Materials For Medical Uses (AREA)
• Mixers With Rotating Receptacles And Mixers With Vibration Mechanisms (AREA)
• Surgical Instruments (AREA)

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• 2008
  • 2008-08-28 KR KR1020107005678A patent/KR101634664B1/ko active Active
  • 2008-08-28 US US12/675,455 patent/US9427715B2/en not_active Expired - Fee Related
  • 2008-08-28 AU AU2008296990A patent/AU2008296990B2/en active Active
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