On the biodegradability, mechanical behavior, and cytocompatibility of amorphous Mg72Zn23Ca5and crystalline Mg70Zn23Ca5Pd2alloys as temporary implant materials
TL;DR: Cytocompatibility studies reveal that neither Mg(72) Zn(23) Ca(5) nor Mg (70) ZN(23] Ca( 5) Pd(2) are cytotoxic, although preosteoblast cell adhesion is to some extent precluded, particularly onto the surface of Mg(-70) zn-free alloy, because of the relatively high hydrophobicity.
Abstract: The evolution of microstructure and mechanical properties of almost fully amorphous Mg72Zn23Ca5 and crystalline Mg70Zn23Ca5Pd2 alloys during immersion in Hank's balanced salt solution (HBSS), as well as their cytocompatibility, are investigated in order to assess the feasibility of both materials as biodegradable implants. Though the crystalline Mg70Zn23Ca5Pd2 sample shows lower wettability and more positive corrosion potential, this sample degrades much faster upon incubation in HBSS as a consequence of the formation of micro-galvanic couples between the nobler Pd-rich dendrites and the surrounding phases. After 22-h immersion, the concentration of Mg ions in the HBSS medium containing the Mg70Zn23Ca5Pd2 sample is six times larger than for Mg72Zn23Ca5. Due to the Zn enrichment and the incipient porosity, the mechanical properties of the Mg72Zn23Ca5 sample improve within the first stages of biodegradation (i.e., hardness increases while the Young's modulus decreases, thus rendering an enhanced wear resistance). Cytocompatibility studies reveal that neither Mg72Zn23Ca5 nor Mg70Zn23Ca5Pd2 are cytotoxic, although preosteoblast cell adhesion is to some extent precluded, particularly onto the surface of Mg70Zn23Ca5Pd2, because of the relatively high hydrophobicity. Because of their outstanding properties and their time-evolution, the use of the Pd-free alloy in temporary implants such as screws, stents, and sutures is envisioned.
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20 Sep 2016TL;DR: In this article, an E-beam firing bar is used to drive staples on each side of the cut in a surgical severing and stapling instrument, which is suitable for laparoscopic and endoscopic clinical procedures, clamps tissue within an end effector of an elongate channel pivotally opposed by an anvil.
Abstract: A surgical severing and stapling instrument, suitable for laparoscopic and endoscopic clinical procedures, clamps tissue within an end effector of an elongate channel pivotally opposed by an anvil. An E-beam firing bar moves distally through the clamped end effector to sever tissue and to drive staples on each side of the cut. The E-beam firing bar affirmatively spaces the anvil from the elongate channel to assure properly formed closed staples, especially when an amount of tissue is clamped that is inadequate to space the end effector. In particular, an upper pin of the firing bar longitudinally moves through an anvil slot and a channel slot is captured between a lower cap and a middle pin of the firing bar to assure a minimum spacing. Forming the E-beam from a thickened distal portion and a thinned proximal strip enhances manufacturability and facilitates use in such articulating surgical instruments.
1,384 citations
Patent•
28 Feb 2012TL;DR: In this article, an endoscopic or laparoscopic instrument is equipped with a handle connected to a proximate end of a conductive shaft, such that the shaft radiates signals as an antenna from the control unit to the sensor and receives radiated signals from the sensor.
Abstract: A surgical instrument, such as an endoscopic or laparoscopic instrument. The surgical instrument may comprise an end effector comprising at least one sensor. The surgical instrument may also comprise an electrically conductive shaft having a distal end connected to the end effector wherein the sensor is electrically insulated from the shaft. The surgical instrument may also comprise a handle connected to a proximate end of the shaft. The handle may comprise a control unit electrically coupled to the shaft such that the shaft radiates signals as an antenna from the control unit to the sensor and receives radiated signals from the sensor. Other components electrically coupled to the shaft may also radiate the signals.
953 citations
Patent•
24 May 2016TL;DR: In this paper, a surgical stapler having a staple cartridge, an anvil, a cutting member having a cutting surface, and a driver operably engaged with the cutting member to move the member relative to the anvil and the staple cartridge is presented.
Abstract: The present invention includes a surgical stapler having a staple cartridge, an anvil, a cutting member having a cutting surface, and a driver operably engaged with the cutting member to move the cutting member relative to the anvil and the staple cartridge. In at least one embodiment, one of the anvil and the staple cartridge defines a slot which is configured to receive at least a portion of the cutting member and guide the cutting member as it is moved relative to the anvil and the staple cartridge. In these embodiments, the slot can also be configured to receive a portion of the driver operably engaged with cutting member and support the driver when it moves the cutting member. In at least one embodiment, the slot is defined by at least one radius of curvature.
932 citations
Patent•
24 May 2012TL;DR: In this article, a surgical cutting and fastening instrument with a shaft coupled to a robotic system is described. But the tool mounting portion includes an electric, DC motor connected to a drive train in the shaft for powering the drive train.
Abstract: A surgical cutting and fastening instrument. The instrument comprises an end effector that has a shaft coupled thereto that is coupled to a robotic system. A tool mounting portion includes an electric, DC motor connected to a drive train in the shaft for powering the drive train. A power pack that comprises at least one charge-accumulating device connected to the DC motor for powering the DC motor is provided.
928 citations
Patent•
09 Feb 2012TL;DR: In this paper, the authors describe an end effector that has a moveable cutting implement and a main drive shaft assembly operably interfaces with the end-effector for transmitting an actuation motion to the movable cutting implements therein.
Abstract: A surgical instrument. Various embodiments of the surgical instrument include an end effector that has a moveable cutting implement. A main drive shaft assembly operably interfaces with the end effector for transmitting an actuation motion to the movable cutting implement therein. A gear drive train is connected to the main drive shaft assembly. The gear drive train is actuated by a motor that is configured to receive control signals from a robotic system. Various embodiments include a sensor arrangement that operably interfaces the end effector to communicate forces experienced by the end effector to the robotic system.
840 citations
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TL;DR: In this paper, the authors used a Berkovich indenter to determine hardness and elastic modulus from indentation load-displacement data, and showed that the curve of the curve is not linear, even in the initial stages of the unloading process.
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22,557 citations
TL;DR: A review of the properties, biological performance, challenges and future directions of magnesium-based biomaterials can be found in this paper, where the authors explore the properties and challenges of magnesium biomaterial.
3,757 citations
"On the biodegradability, mechanical..." refers background in this paper
...This means that mechanical integrity of the implant is spoiled before the tissue has sufficient time to heal the bone.(33)...
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TL;DR: In this article, the authors discuss the concept of nanocomposite coatings with high hardness and low elastic modulus, which can exhibit improved toughness, and are therefore better suited for optimising the wear resistance of real industrial substrate materials (i.e., steels and light alloys, with similarly low moduli).
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TL;DR: A group of degradable thermoplastic polymers that are able to change their shape after an increase in temperature enables bulky implants to be placed in the body through small incisions or to perform complex mechanical deformations automatically.
Abstract: The introduction of biodegradable implant materials as well as minimally invasive surgical procedures in medicine has substantially improved health care within the past few decades. This report describes a group of degradable thermoplastic polymers that are able to change their shape after an increase in temperature. Their shape-memory capability enables bulky implants to be placed in the body through small incisions or to perform complex mechanical deformations automatically. A smart degradable suture was created to illustrate the potential of these shape-memory thermoplastics in biomedical applications.
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TL;DR: Results of this study suggest, that the conclusions drawn from current ASTM standard in vitro corrosion tests cannot be used to predict in vivo corrosion rates of magnesium alloys.
1,237 citations