Abstract: The invention relates to a cylinder head (1) for an internal combustion engine, with a prechamber (2) which is arranged in the cylinder head (1) and is defined by an inner wall surface (11) of a prechamber wall (5), wherein the prechamber (5) comprises a first chamber portion (3) and a second chamber portion (4), wherein the first chamber portion (3) has a greater maximum diameter (D) than the second chamber portion (4), wherein at least one ignition device (16) opens into the first chamber portion (3), and the second chamber portion (3) comprises at least one overflow channel (7) for the passage of flow into a combustion chamber (8) which adjoins a fire deck (6). Am improved dissipation of heat can be achieved if at least one inner wall surface (11) of the first chamber portion (3) comprises at least one first flattened portion (13).

Abstract: A weld cap is configured and dimensioned to interact with a resilient element, e.g., a spring, and a structural member, e.g., an end cap, so as to securely position the spring relative to the end cap. The weld cap functions to distance the welding process and associated welding energy from the spring, thereby avoiding and/or minimizing any potentially undesirable annealing effect associated with securing/welding the spring relative to the end cap. A first weld cap interacts with the spring at a first end region thereof, and a second weld cap interacts with the spring at a second end region thereof, thereby effectively securing the spring with respect to opposed end caps at either end of an elongated spinal stabilization device. Alignment grooves or channels may be provided for orienting or aligning the spring with respect to the end caps and weld caps.

Abstract: Spinal stabilization devices, systems and methods are provided that include a stabilization member including a first structural member that mounts to a pedicle screw, a second structural member adjacent the first structural member and that can move away therefrom, a resilient element mounted between the structural members and that elongates to accommodate relative movement therebetween, and a travel-limiting structure mounted between the structural members and that defines and imposes upon the stabilization member a maximum distance by which the first and second structural members may be separated. The travel-limiting structure can include an axially inextensible, laterally flexible elongate element, e.g., wire-rope cable, disposed between the structural members.

Abstract: Spinal stabilization devices, systems and methods are provided that include a spring junction wherein a structural member is mountable to a spine attachment fastener and a resilient element is affixed to the structural member along an attachment region of the resilient element. The attachment region is disposed physically separately with respect to an active region of the resilient element. The attachment region can include a weld region produced via an E-beam welding process involving temperatures of 1000° F. or greater, wherein a heat-affected zone adjacent the weld region is disposed physically separately with respect to the active region. The resilient element may be a coil spring including bend regions adjacent its outermost (i.e., last) coils wherein the material of the coil spring initially bends away from the last coil, then bends back toward the last coil before terminating near the last coil.

Abstract: Systems, assemblies and methods for assembling a sheath member with respect to a spinal stabilization device are provided. The disclosed sheath assembly includes at least one connector ring mounted with respect to a sheath member. The connector ring defines an inner wall that shields the sheath member from elements positioned therewithin, e.g., spring members, and generally includes a plurality of radially-spaced notches. The connector ring receives the sheath member within an internal cavity and is secured thereto by crimping, compression or swaging. The sheath assembly may be mounted with respect to a spinal stabilization device by crimping, compressing or swaging the connector ring to an underlying structure, e.g., an end cap or associated flange. The internal cavity of the connector ring is generally defined by an inner face, an outer wall and an intermediate apex region. Methods for assembly are also disclosed.

Abstract: Spine stabilization devices, systems and methods are provided in which torsion member extends between first and second stabilization devices that are oppositely positioned relative to the vertebrae. The torsion member includes a (i) a first segment that is substantially co-planar with and perpendicular to the axis of at least one of the stabilization devices; (ii) a second segment that extends from the first segment and that is angularly and upwardly oriented relative to the first segment; (iii) a third segment that extends from the second segment, is substantially perpendicular to at least one of the stabilization devices, and is oriented in a plane that is elevated with respect to, but substantially parallel to, the plane of at least one of the stabilization devices, (iv) a fourth segment that extends from the third segment and that is a substantial mirror image of the second segment; and (v) a fifth segment that extends from the fourth segment and that is a substantial mirror image of the first segment..

Abstract: Spine stabilization devices, systems and methods are provided in which a single resilient member or spring is disposed on an elongate element that spans two attachment members attached to different spinal vertebrae. The elongate element passes through at least one of the two attachment members, permitting relative motion therebetween, and terminates in a stop or abutment. A second resilient member is disposed on the elongate element on an opposite side of the sliding attachment member, e.g., in an overhanging orientation. The two resilient members are capable of applying mutually opposing urging forces, and a compressive preload can be applied to one or both of the resilient members.

Abstract: A dynamic spine stabilization device is provided that includes at least one force imparting member, e.g., a spring. The force imparting member is adapted to deliver a force of between about 150 lb/inch and 450 lbs/inch, and restrict the relative travel distance between said first and second pedicles to a distance of between about 1.5 mm and 5 mm. The spinal stabilization devices also have a minimal impact on the location of the center of rotation for the spinal segment being treated. By providing resistance in the noted range and restricting the travel distance to the noted range, it has been found that the stabilization device provides a desired level of stabilization, as reflected by range of motion values that closely approximate pre-injury range of motion levels.

Abstract: Spinal stabilization devices, systems and methods are provided that include at least one pedicle screw and at least one mechanism that supports three degrees of rotational freedom relative to the pedicle screw. The mechanism may include a universal joint mechanism or a ball and socket mechanism. In the case of the ball and socket mechanism, at least one spherical element is mounted with respect to the at least one pedicle screw and a socket member cooperates with the spherical element. The spherical element and the socket member cooperate to define a dynamic junction that allows the socket member to move relative to the ball element while remaining engaged therewith. The dynamic junction is advantageously incorporated into a spinal stabilization system that includes additional pedicle screw(s), spherical element(s) and socket member(s). The spinal stabilization system may incorporate dynamic stabilizing member(s) to so as to provide clinically efficacious results.

Abstract: A pedicle screw assembly is provided that includes a pedicle screw and a preloaded set screw. The set screw is preloaded in a threaded, central aperture formed in the head region of the pedicle screw. An interference is advantageously formed on the set screw to prevent dislodgement of the set screw, e.g., during shipment and/or clinical placement of the pedicle screw. An upwardly extending collet is generally formed in the head region of the pedicle screw, the collet being sized to receive a spherical element therearound. Advancement of the set screw relative to the pedicle screw secures the spherical element relative to the pedicle screw. The spherical element typically includes a socket member that cooperates with a dynamic stabilizing member. The pedicle screw assembly and dynamic stabilizing member are advantageously used as part of a spinal stabilization system to provide clinically efficacious results.

Abstract: A surgical implant is provided that includes first and second abutment surfaces between which are positioned a force imparting mechanism. A sheath is positioned between the first and second abutment surfaces, and surrounds the force imparting mechanism. The sheath is fabricated from a material that accommodates relative movement of the abutment members, while exhibiting substantially inert behavior relative to surrounding anatomical structures. The sheath is generally fabricated from expanded polytetrafluoroethylene, ultra-high molecular weight polyethylene, a copolymer of polycarbonate and a urethane, or a blend of a polycarbonate and a urethane. The force imparting member may include one or more springs, e.g., a pair of nested springs. The surgical implant may be a dynamic spine stabilizing member that is advantageously incorporated into a spine stabilization system to offer clinically efficacious results.

Abstract: A pedicle screw is provided that includes an upwardly extending collet. The collet may include downwardly extending slots that define deflectable segments therebetween. When a spherical element or other structure, e.g., a non-dynamic stabilizing element, is positioned around the collet, introduction of a set screw causes outward deflection of the upstanding segments into engagement with the spherical element. A snap ring may be interposed between the collet and the spherical element to facilitate positioning therebetween. In an alternative embodiment, a non-slotted collet is employed. In such embodiment, the collet and the spherical element may be threadingly engaged and may include a snap ring therebetween. The pedicle screw subassemblies may be incorporated into a spinal stabilization system which may include a dynamic stabilizing member to provide clinically efficacious results.

Abstract: A system and method for effecting multi-level spine stabilization is provided. The system includes a plurality of pedicle screws which are joined relative to each other by elongated members, e.g., rods. At least one of the rods includes a dynamic stabilizing member. The pedicle screw junctions are dynamic, i.e., free relative movement of a socket member is permitted relative to a fixed spherical element. Placement of the spherical element may be facilitated using a guidewire system that includes a guidewire and a tapered guide member. A spine stabilization assembly is also provided that includes an attachment member that includes an opening. At least one spherical element that includes a rod-receiving channel is movably mounted within the opening with three degrees of rotational freedom. The spherical element generally defines an elliptical rod-receiving channel that is deformable to a circular opening to firmly engage a rod positioned therein.